https://cpw.cvlcollections.org/files/original/ef4b1bda61f8d909a07939fd61df0438.pdf 0fe204f01803d23f1032246c7e4e7c94 PDF Text Text 1 (Supplemental State of JOB PROGRESS REPORT to report of 1 January - 31 December 1987) ~C=o~l~o~r~a~d='o~ _ Project: (SE-11-2) Period Covered: 1 January - 30 June, 1988 Personnel: : Peregrine Falcon Restoration G.R. Craig, Colorado Division of Wildlife Colorado College. Program and J.H. Enderson, The The previous Job Progress Report summarized activities conducted during the 1987 breeding season (generally that period from 1 April through 31 August). Since the reporting period has been amended from a calendar to a fiscal year, work accomplished during the breeding season would be split between two reporting periods in the future. Since it is ineffective to attempt to report on progress in the midst of the field wor k , the progress for each field season will be reported at its conclusion. Hence, this interim report merely states that investigations undertaken during this period will be compiled, summarized and reported in the next (1 July 1988 to 30 June, 1989) Job Progress Report. ��3 (Supplemental JOB PROGRESS REPORT to report of 1 January - 31 December State of Colorado Project: (W-151-R-1 ) Period Covered: 1987) Bald Eagle Nest Site Protection and Enhancement Program 1 July, 1987 - 30 June, 1988 Personnel: G.R. Craig, Colorado Division of Wildlife and R.L. Knight, Colorado State University. ABSTRACT Breeding bald eagles occupied 8 territories in Colorado in 1988. One new territory was located and a pair failed to return to another site. In all, 8 young were successfully fledged by 6 pairs. Artificial nests were constructed at 2 sites t~ replace nests lost to high winds, Samples of feather pulp and blood sera were obtained from 6 nestlings to determine genetic similarity of the Colorado population to adjacent populations. This Job Progress Report represents a preliminary analysis and is subject to change. For this reason, information presented herein MAY NOT BE PUBLISHED OR QUOTED without permission of the author. ��5 BALD EAGLE NEST SITE PROTECTION AND ENHANCEMENT PROGRAM Gerald R. Craig SEGMENT OBJECTIVES 1. Monitor nest site occupancy and reproductive 2. Document survival rates and mortality 3. Determine migration 4. Determine if philopatry 5. Determine nest site tenacity by individual breeding eagles. 6. Quantify document 7. Document pesticide contamination analysis of nonviable eggs. 8. Where necessary, occupancy. and wintering success. factors. areas. occurs in breeding eagles. nesting habitats and associated foraging areas in an effort to nest site parameters conducive to improved reproduction. implement through eggshell measurement actions to stabilize nests and chemical and maintain METHODS AND MATERIALS This work will be a coopeiative endeavor Knight of Colorado State University. between the Division and Or. Richard 1. Annually visit all documented breeding sites to determine the presence of bald eagles. Pairs at territories will be documented by DWMs and other field personnel. Previously unrecorded pairs will probably be revealed in the course of aerial eagle and waterfowl flights. DWMs will confirm actual inCUbation from ground visits. 2. Occupied territories will be visited by DWMs periodically throughout breeding season to determine hatch of young, nesting failures, etc. 3. In May and June, a Utility Worker will observe breeding eagles from a distance and endeavor to follow thei r movements to locate important foraging areas. Responses of eagles to various human activities and land u~es will be recorded. 4. In June, when the young are determined to be old enough to band, sites will be visited by Craig and Knight to place a federal band on one leg and a colored, alpha numeric marker on the other. The color markers will oermit identification if the young return in subsequent years. During the same nest visit the following will be recorded: Physical parameters such as tree species, height, DBH, condition, and dominance. Nest condition, size, and location. Vegetative community and land use practices. the �6 In addition, collect prey remains, nonviable eggs and eggshell fragments. 5. When necessary, remedial actions will be taken to stabilize nests that are threatened by wind throw. Should the tree be decadent and in danger of falling, an artificial nest base may be placed in a suitable, adjacent tree. Action will be taken only after it has been deemed desirable to encourage the eagles to nest at the same location. RESULTS AND DISCUSSION Territory Occupancy Said eagle nesting activities for Colorado are summarized in Table 1. In 1988, 8 territories (Adams, La Plata ~1, Moffat #1 and #2, Montezuma ~2 and #3, and Rio Blanco 1*1 and #3) were occupied. The territory at Moffat ~3 was not checked. A new pair was located in the vicinity of Cortez and the site was designated Montezuma #3. Montezuma #3 is similar to the Archuleta site in that it is upland and located in a grove of cottonwoods that are surrounded by irrigated pasture land. The Archuleta site was vacant in 1988 and it is possible that pair may have re located e 1 sewhe re in the vic inity since a detailed su rvey was not initiated. Land Status Ownership of the terr,tories have been reported previously (Craig 1987). The recently discovered pair (Montezuma #3) occupy private property. The landowners are very protective of the_site and discourage trespass. Reproduction Reproductive efforts of the 8 pairs are summarized 1n Table 2. In summary, 8 young were fledged in 8 nesting attempts (1.0 young per attempt) by 6 successful pairs (1.33 young per successful palr). The pair at the Adams County site failed when the entire tree blew Over while they were incubating. Egg remains could not be located since the tree was standing in 2 to 3 feet of water. In an effort to encourage renesting, an artificial nest was placed in an adjacent, live tree. Although the pair took over the nest and added sticks, they did not recycle. Failure to do so may be due in part to replacement of the original male with a new mate sometime in the interim that the first tree blew down and placement of the artificial nest. It is also possible that C~lorado ~ay be situated too far north for pairs to renest. Although the pair failed to recycle and produce a second clutch of eggs, they continued to frea~2n~ t~e site throughout the summer . .u.s previously reported (Craig 1987), the nest at Moffat Co. #2 blew out killed bo th young in 1987. By October of that same year, the pair reconst ructed a suc st ant i a 1 nest nearby. In 1988 the pa ir produced successfully fledged 2 young at the new nest. Moffat Co. #3 was not checked 1988. and had and in �7 When the nest at Montezuma Co. #3 was visited after severe winds, the nest was partially destroyed and in danger of disintegrating. One nestling was present and a sing1e, nonviable egg was discovered amidst the detritus on the ground, thus at 'least 2 eggs were produced. The nest was partially stabilized with cross bracing but despite the efforts, the it fell before the nestling fledged. Fortunately, the young was old enough to maintain its balance on the bare limbs and achieved independence. In September. an artificial structure was affixed in the fork where the previous nest was situated and the nest was rebuilt. The landowner had observed the ad~lts in the area as recently as 10 days previously so it is anticipated that the eagles will adopt the new nest. Reproductive success could not be confirmed at Rio Blanco Co. #3. Barry Dupire (OWM) observed the nest from a distance and confirmed 3 young earlier in the season, but the site could not be relocated from the ground on subsequent visits. It is poss i b 1e that the nest cou 1d have b 1cwn down, but that cou 1d not be confirmed despite extensive searching. Hence, it was assumed that the site failed. Culmen length and foot pad length measurements were obtained for 6 of the eaglets. The nestlings at Moffat Co. #2 were deemed too old to approach without danger of causing premature fledging, so no data were obtained. In addition to the measurements, feather pulp ana n Iood samples were procured from the 6 nestlings. The samples will be pooled with otheF samples collected throughout the U.S. and Canada for comparison to determine the affinity of Colorado's eagles with other subpopulations. Eggshell Condition One ncnv i ab 1e egg was co 11ected from Montezuma Co. #3. The egg '..•• as broken thereby invalidating pesticlde analysis, but the shell thickness measurements will be obtained. Nest Stabilization Efforts Actions to stabilize nests were reported above. Artificial nest platforms were placed at the Adams County site and the Montezuma Co. #3 site. The Adams County platform was constructed in an effort to maintain the pair on territory, induce production of a second clutch and shift the pair away from a grove of dead cottonwoods to a substantial, living tree. The effort was successful in all objectives save production of a second clutch of eggs. It is too early to ascertain results of the reconstruction of the Montezuma Co. #3 nest. Although it was ~revicusly suggested that Moffat Co. #2 be relocated (Craig 1987), the pa i r ret.urned in the fall of 1987 and constructed a new nest on a more substantial limb. Montezuma Co. #1 was also slated for stabilization, but the work was not accomplished this period. Work should be initiated to secure the present nest and build an artificial nest in a neighboring tree as an alternate should the first nest be destroyed. �8 LITERATURE CITED Craig, G.R. 1987. Bald Eagle nest site protection and enhancement Job Prog. Rep., Colo. Div. Wildl. Res. Rep., Jan., pp1-10. - Prepared by: C .~. ~ Gerald R. era:; Wildlife Researcher C program. �Table 1. Bald Eagle Nesting Efforts in Colorado ~- -. ---_. --- -- .. _- - - --_._. - Site 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 La Plata Co. #1 t-loffatCo. #1 La Plata Co. lt2 Grand Co. Montezuma Co. ttl Rio Blanco Co. #1 Rio Blanco Co. #3 Weld Co. Montezuma Co. #2 Moffat Co. #2 Moffat Co. #3 Adams Co. Archuleta Co. Montezuma Co. #3 1egg Total Young Total Pairs IA = Inactive -------- IA IA IA IA IA lyng 2yng 2yng 2yng 1yng -- 2yng 2yng 2yng·Oyng ---- Oy.ng Oyng -- ---- ------------ 0 1 1 2 4 4 2 2 -- --- --- -- ---- --- -- -- -- -- --------- -------- --------- 4 3 1 3 -- -- -- -- ? -IA IA A ----- -- ---- -0 1 eggs ? ? ? ? ? 2yng 2yng -- 2yng Oyng lyng IA IA IA IA IA IA IA IA IA IA IA IA A A IA IA IA A 1yng 1yng ? eggs Oyng 2yng -- 3yng 2yng 2yng 2yng Oyng ---- 2yng 2yng eggs --- -- -- 2yng 1yng ---- -- -- 1yng ---- --' -- 1egg --- -- -- -- eggs ----- -- eggs 2yng 2yng IA IA IA 2yng 1yng IA lyng Oyng IA 1egg 2yng -- -- -- -- -- -- -- 3 6 4 2 2 6 4 6 5 5 10 10 9 3 lyng 1yng IA IA IA 2yng A IA lyng 2yng ? eggs IA lyng 8 8 A = Active 1.0 �10 Table Bald Eagle Nesting 2. Colorado Age of 8 i rds t·1a 1e Female Slte Adult Adult Adult Adult :.1offat Co. ~1 Adult Adult ~1offat Co. ..•,,'-') Adult Adu l; 1-1ontezuma Co. #2 Adult Adult Adu 1t Adu It Adams Co. La Plata Co. #1 Montezuma Co. ;t3 Young Produced Young Fledged 0 0 ...• ~ ,.. least 2 L Rio Blanco Co. ,,~ Adult Adult .~? ,., ,:I, i1 2 eggs produced. .-' Aault v Nest tree blown down. .-..i,.. Adult o u Comments -, Co. j;1 Tetal - 1988 '- Rio Blanco ...~ Efforts u Not relocated. � https://cpw.cvlcollections.org/files/original/a6e96618e1103fe4aa74093f987848ae.pdf 4016036c44b36a9f7efca62a633314b8 PDF Text Text 1 JOB PROGRESS REPORT State of: Project : Colorado W-152-R Work Plan: _3_: Job Title: Job _ 13 Responses of Sage Grouse to Vegetation Fertilization Period Covered: Author: ---,A~v~i~a!..!.!n~R~e s::!..!e~a~r~cc!.!h 01 January through 31 December 1987 Orrin B. Myers Personnel: C. E. Braun, Colorado Division of Wildlife; O. B. Myers, G. C. White, Colorado State University; C. Cesar, L. Upham, U. S. Bureau of Land Management ABSTRACT The response of sagebrush (Artemisia tridentata) and,sage grouse (Centrocercus urophasianus) to nitrogen fertilization was studied in North Park, Jackson County, Colorado. Sagebrush plants responded to application of 112 kg-N/ha in Fall 1985 with increased growth, increased levels of foliar crude protein, and reduced levels of foliar coumarins. Sage grouse used fertilized study plots for feeding significantly more often than adjacent unfertilized plots. When presented with 8.1. wyomingensis (ATW) and fertilized ATW (FATW) in paired choice experiments, captive sage grouse consumed significantly more fertilized than unfertilized sagebrush (ATW). Captive grouse digested dry matter, crude protein, and energy in FATW and ATW at the same rates but the nitrogen balance of birds fed FATW was significantly improved over those fed ATW. Reproductive success was measured for radio-marked hens captured near fertilized plots and compared with those not associated with fertilized study areas. Apparent differences in reproductive success among grouse could not be distinguished from any pretreatment differences. ��3 RESPONSES OF SAGE GROUSE TO VEGETATION FERTILIZATION Orrin B. Myers P. N. OBJECTIVES The project is part of a two-phased study to on sage grouse winter distribution in mining ecology, and to 2) evaluate whether nitrogen grouse winter habitat, can be used as a tool available to sage grouse. The focus of this Phase 2. 1) collect baseline information areas and on grouse feeding fertilizer, when applied to sage to mitigate reduction in habitat portion of the project is on SEGMENT OBJECTIVES 1. Document chemical and growth response of sagebrush to nitrogen fertilizer, 2. Evaluate feeding preferences of sage grouse for fertilized and unfertilized sagebrush subspecies, 3. Estimate digestibility of fertilized and unfertilized sagebrush subspecies, and 4. Monitor reproductive parameters of radio-marked' sage grouse to learn if sage grouse fitness is affected by fertilizer treatment. DESCRIPTION OF STUDY AREA The study area is in North Park, Jackson County, Colorado. The Park is an intermountain basin at an elevation of about 2,500 m. It is drained to the northwest by the North Platte River, which is fed by many smaller streams. Topography is flat to rolling with numerous ridges and benches. Climate is cold and dry with an average annual frost-free period of 46 days. Sagebrushdominated grasslands cover upland sites in the Park, and grasses and sedges occur in native and irrigated meadows that border drainages. Artemisia tridentata is the dominant sagebrush species and includes 2 subspecies, 8· 1. wyomihgensis (ATW) and 8.1. vaseyana (ATV). Other species of sagebrush occurring with limited distribution in North Park are 8. longiloba, 8. cana, and 8. argillosa. METHODS In October-November 1985 ammonium nitrate fertilizer (33.5% N) was applied at a rate of 112 kg-N/ha to 330 ha of sagebrush rangeland (Fig. 1). Thirty-three 20-ha blocks were randomly-selected with 11 blocks distributed in each Area. The northern and southern 10 ha of each block were randomly assigned as fertilized or control and treated accordingly. In October 1987 fertilizer was applied to an additional 6 I-ha plots (Fig. 1). �4 A E3 8 B c Jackson County El 1987 1985 B2] • =er t i I ized D D Contiol El -.~ 1 km Fig.1. Colorado. Locations I of fertilized study plots in North Park, Jackson County, �5 Sagebrush foliage was collected each quarter from a ra~dom sample of the 33 experimental blocks. Four blocks from each of the maln study areas were sampled, and a total of 5 randomly-located plants of the 2 big sagebrush subspecies were clipped from the control and fertilized halves of each study block. In addition, individual plants of each subspecies were examined in control and fertilized study plots for evidence of browsing by sage grouse. Sage grouse were trapped at nocturnal roosts to attach radio packages and to provide birds for captive experiments. Fertilized study areas were scanned for radio-marked birds >3 times weekly prior to and during the breeding season. Radio-marked bTrds also were located periodically to assess any use of experimental blocks and to monitor reproductive success. Captive birds were placed into metabolic cages and fed fertilized and unfertilized sagebrush in single food digestibility trials and in paired choice experiments. Feeding trials were conducted during March-April 1987 to estimate feeding preferences for fertilized and unfertilized Wyoming big sagebrush, Artemisia tridentata wyomingensis (ATW). Similar amounts of control ATW and fertilized ATW (FATW) were placed on the left or right side of each cage prior to the morning feeding period. Positions of each treatment in the cages were determined randomly. Birds were allowed to feed for 60 minutes after which the sagebrush and spillage was removed and weighed. Digestion trials were accomplished by adding known amounts of fertilized or unfertilized sagebrush to cages at about sunrise. Additional measured amounts of sagebrush were added by about 1400 hours as needed. Sagebrush branches also were placed on top of cages in the morning and weighed at night to provide an estimate of water loss during the day. After the evening feeding period sagebrush was removed from the cages and weighed. Spilled sagebrush was removed from the bottom of the cage, weighed and discarded. Fecal droppings were collected and stored overnight in resea1able plastic bags. Fecal and caecal droppings were collected and placed into plastiC bags before additional sagebrush was added to cages the following morning and subsequently placed in frozen storage. A 8 c Twenty-meter transects in 5 m segments were used to sample sagebrush plants in fertilized and control study plots during early spring prior to the onset of growth TOTAL 2 (Apr-May). Transect segments were 3.20 3.11 3.53 PLANTS/m placed at random locations along lines walked through the plots. Fig. 2. Relative densities of sagebrush Plant subspecies, height, and line subspecies on each of 3 main fertilized intercept distance were recorded for study areas in North Park, Jackson all big sagebrush plants under the County, Colorado. line transect. Densities of sagebrush plants were similar on the 3 fertilized study areas, although the relative proportions of each subspecies were not the same for each area (Fig. 2). Each plant was examined for evidence of feeding by sage grouse and 3 growth leaders, including leaves, from 1986 were measured on each plant. Sagebrush plants clipped during early spring foliage collections also were examined for evidence of feeding activity by sage grouse. Q . �6 Numbers of male and female grouse attending leks were counted between about 0500 and 0730. From 01 April through the first 2 weeks of May. Ground searches were made for new or relocated leks during the period when known leks were active. Aerial searches for leks were conducted on 12-13 May. Sagebrush foliage samples were prepared for analyses by separating leaves from stems and pooling equal amounts of leaves from each plant into composite samples. Composite samples for each subspecies collected on the control and treatment halves of each study block were ground in a mortar and pestle by freezing with liquid nitrogen. Composite foliage samples collected during feeding trials were treated in the same manner. Grouse fecal and cecal droppings collected in the course of feeding trials were freeze-dried and then ground in a mortar and pestle. Coumarin content of winter-collected sagebrush leaves was indexed using the methods of Welch and McArthur (1986). In this method, percent transmittance values are produced which are assumed to be inversely related to the coumarin content of sagebrush leaves. Measurements of percent transmittance was made in triplicate on ATW and ATV plants. Dry matter content of foliage and grouse droppings was determined after drying overnight at 100 C. Samples were ashed overnight at 500 C to determine organic matter and ash content. Kjeldahl nitrogen (Horwitz 1980) was measured in addition to neutral detergent fiber, neutral detergent solubles, and acid detergent fiber (Van Soest 1963~, Q; Mould and Robbins 1981, Van Soest 1982). Soil samples were collected on 13 October from each of the 6 study plots to receive nitrogen fertilizer in Fall 1987. Adjacent control plots also were sampled. Each plot was subsampled at 6 random locations. Subsamples were placed into a plastic bucket and thoroughly mixed before removing about 750 cc for analyses. Analyses of soil samples were performed by the Soil Testing Laboratory at Colorado State University. AREA C -.~ I 33 34 4 3 1 km 10 On 05 August a wildfire burned' ·[Il BU"'n SIte ~ existIng approximately 75 ha of sagebrush in the southern half of S9 T8N R78W. The burn Fig. 3. Location of wildfire in destroyed approximately 80% of experimental block #16 in Area C (Fig. 3) relation to fertilized study blocks about 1.5 km west-southwest of the Perdiz in North Park, Jackson County, Lek. Colorado. PlOts RESULTS AND DISCUSSION The most obvious response by sagebrush to fertilization was increased growth (Table 1). New growth on nearly 400 plants was measured in March and April 1987, to determine the amount that growth of leaders was increased in �7 the first year of response. For this parameter the 2 dominant subspecies, ATV and ATW, responded similarly to the fertilizer treatment. New growth from fertilized plots was more than twice as long as that from unfertilized plots (Table 1). The size of individual leaves and the number of seed heads also appeared to have been increased by fertilization. Table 1. Length of annual growth increment (cm) of fertilized (F) and unfertilized (C) sagebrush plants. Subspecies Treatment n x SE C 118 96 68 101 3.0 7.1 2.9 7.3 0.1 0.2 0.2 0.3 8. 1· vaseyana F 8. 1· wyomingensis C F ANOVA. Source df MS .E value E. >.E Subspecies Treatment Subspecies x Treatment Error 1 1 1 379 0.21 1,665.04 1.18 4.30 .0.06 401. 41 0.27 0.80 0.0001 0.60 The secondary chemistry of sagebrush plants was influenced both by subspecies involved and fertil ization (Table 2). Coumarin level s measured by percent transmittance values were lower in ATW than in ATV, and coumarins were lower in fertilized plants than in unfertilized plants (Table 2). The reduction of coumarins in fertilized plants conforms to predictions by Bryant et al. (1983) that plant investments in chemical defenses are a function of the plant's carbon/nutrient balance. With increased nutrient availability, plants would be expected either to increase their investment in defensive substances or to increase growth without a proportional increase in defensive substances. If other defensive substances follow coumarin levels, then it appears that sagebrush plants adopt the strategy of maximizing growth rather than investing in defense compounds. The result of relatively lower levels of anti-herbivore defense chemistry in fertilized sagebrush could be that such plants contain higher levels of available nutrients. Levels of crude protein in winter sagebrush foliage were significantly influenced by fertilization (Table 3, Fig. 4). ATW samples contained more crude protein than ATV (E. = 0.0001) and each subspecies showed about the same proportional response to fertilization (E. > 0.9). There was considerable block-to-block variability in vegetation response. In Area B the terrain is more variable and contains more soil types than the other areas. If Area B was considered separately there was no increase in protein levels (E. > 0.05). �8 Table 2. Relative levels of coumarins in fertilized (F) and unfertilized (C) sagebrush plants as measured by percent transmittance. Subspecies Treatment 8· 1. vase~ana 8· 1. w~omingensis 4.4 4.2 2.5 3.5 32.4 44.3 38.4 61.8 15 15 15 15 C F C F SE X D. ANOVA Source df MS E value £ > Subspecies Treatment Subspecies x Treatment Error 1 1 1 56 2070.93 4,679.90 497.08 208.04 9.95 22.50 2.39 0.003 0.0001 0.13 E Table 3. ANOVA for effect of nitrogen fertilization on crude protein levels in winter sagebrush foliage. Source df Block Subspecies Treatment Subspecies x Treatment Error 11 1 1 1 33 MS 0.0003 0.0102 0.0023 0.0000 0.0001 E value £ 3.89 111.39 24.77 0.01 0.0012 0.0001 0.0001 0.9 > E Observations of feeding activities of free-ranging grouse and of captive birds indicated that grouse preferred fertilized sagebrush over unfertilized sagebrush. The number of transects in which feeding activity by grouse was found was greater on fertilized plots than on adjacent control plots (Fig. 5) (£ < 0.01). Twenty-eight percent of the transects on fertilized plots contained plants that had been fed upon by grouse compared to 3% on the unfertilized plots. Grouse did not appear to increase their use of ATV. Maintenance of captive birds was difficult. Birds did not consume enough sagebrush to maintain mass and did not acclimate behaviorally to captivity well enough to allow periodic weighings. Mealworms and a gamebird ration were added to cages in addition to sagebrush on days when digestive trials were not being conducted. Birds soon learned to feed upon mealworms contained in 500 ml beakers but did not consume any of the gamebird ration in the beakers. The �9 14~--------------------------' c=J Control 1:: :1 Fertilized 2 o ATV ATW Fig. 4. Crude protein levels in winter sagebrush foliage samples from fertilized study blocks in North Park, Jackson County, Colorado. combination of sagebrush and mealworms appeared to arrest declines in mass shown by the birds for a time, however some birds lost mass even with the meal worm supplement (Fig. 6). ~ m ~An "ATI E t ~ ao w ~ Captive bird studies began 7 February when a yearling female (Band # 5845) was confined. Additional birds were captured 5 and confined (Table 4). Several preliminary digestion and preference 0 r c r c trials were conducted prior to 1 April when 4 birds wer~ available for trials. us APi-HAY About 750 g of ATW and FATW were put into Fig. 5. Use of sagebrush plants by cages for the digestion trails. Larger grouse on fertilized (F) and amounts were added on days when trials unfertilized (C) study plots in were not conducted. North Park, Jackson County, Sage grouse selection for fertilized and Colorado. unfertilized ATW also was studied by allowing captive grouse to choose between FATW and ATW plants. Sage grouse consumed an average of 2.1 times more FATW than ATW (Table 5), and all birds in all trials consumed more FATW than ATW. Each treatment was intended to occur in the left and right cage positions with equal frequency but problems with birds and an incorrect treatment assignment prevented this arrangement. Unequal representation of treatments in the cage positions could have confounded feeding preference with a learned propensity to feed at a 15 10 �10 Table 4. Captive sage grouse used in feeding trials, 1987. Band Age Date captured 5845 Yrlg 5 Feb 4000 5848 5851 5852 5854 Ad Yrlg Yrlg Yrlg Yrlg 18 11 21 21 21 5858 Yrlg 31 Mar # Comments Released 2/22/87 with radio (151.089); radio recovered after raptor mortality on 3/11/87. Died in captivity 2/21/87. Died in captivity 3/27/87. Released 4/13/87. Released 4/13/87. Released 4/13/87 with radio (151.050); radio active as of 7/8/87. Released 4/13/87 with radio (150.989); radio signal last received 4/18/87. Feb Mar Mar Mar Mar particular cage position. An additional analysis was performed by partioning the data set and using observations such that treatments were distributed evenly among birds and cage positions, thereby removing any confounding of treatment and cage position. Analysis of this data set indicated that an average of 2.6 times more FATW than ATW was consumed by grouse (P < 0.005). Although birds consumed significantly more fertilized than unfertilized sagebrush in the choice experiments, the intake of dry matter by captive grouse was not affected by fertilization when a single food was offered (£ = 0.82). Daily consumption of dry matter averaged 51 g (range = 28 - 82 g) for ATW and 48 g (range = 27 - 68 g) for FATW. The daily intake of nitrogen was similar (.~AT\J = 0 -. 9 g, SEAT~ = 0.08; KFAT\J = 1.2 g, SEFAT\J = 0.08; £ =0.14) for the sagebrush treatments, Dut the amount of nitrogen retained by birds was significantly affected by fertilization (Table 6). This parameter also was affected by among bird differences (£ = 0.02). Three birds behaved Similarly and produced consistent results compared to a fourth bird, which had consumption rates that consistently were lower than the others. Table 5. Consumption (g) of fertilized and unfertilized Wyoming big sagebrush by captive sage grouse during one-hour preference trials in March - April 1987. Treatment n Unfert ilized Fertil ized 15 15 5.8 12.1 111 SE £ > 1.1 1.2 0.001 �11 1.5 • 1.4 , ,, , r=-; b1 ~ 1.3 • '-/ U) U) .<:C ::c >-< Q 1 .1 --. -, -, <, 1.0 0 iII ...._ 1.2 A 0.9 0.8 0 100 90 , .... E-< ::r:: H 8 6 ,, ~ Q 4 _ ......:1 12 14 16 18 10 12 14 16 18 ._ ..•.... 80 .•.. W ::;:: -< !:z:; 10 •,, •••........ <:» 2 -, 70 H Q H 60 B 0:: 0 50 0 2 4 6 8 DAYS IN CAPTIVITY Fig. 6. Absolute (A) and proportional sage grouse hens used in captive feeding (8) losses of body mass of 2 captive experiments. �1,2 Table 6. ANOVA for effects of experimental fertilization on nitrogen balance of captive sage grouse. Source df Bird Treatment Bird x treatment Laboratory rep. Error 3 1 3 1 31 MS .E value 0.686 1.072 0.122 0.013 0.185 3.71 5.81 0.66 0.07 £ > .E 0.02 0.02 0.6 0.8 True metabolizable energy values (TME) cannot be obtained from birds without estimates of excreted fecal metabolic energy and urinary endogenous energy. These estimates can be obtained by Sibbald's (1979) TME assay using fasted birds. Apparent metabolizable energy (AME) values can be obtained from the conditions of this study by comparing energy intake and energy retention and correcting energy retention to a zero nitrogen balance (Sibbald 1979). The slope of the line relating energy intake and the corrected energy retention provides a means for estimating AME. Analysis of covariance can be used to test for differences in slopes to estimate treatment effects. ATW and FATW treatments were retained by birds at the same rates (Fig. 7, Table 7) and treatments alone did not affect the amounts of energy retained (£ = 0.8). 300, • FATI 250 " - C' B :J< u 200 - •••• ,. ~ w aJ 150 f- .. 0 w :=: -c 100 I- •" JIll ~ ~ •• " An' • • .. 50 I- 0 0 100 200 300 "00 500 INTAt::E (KCtl I) Fig. 7. Apparent metabolizable energy adjusted to zero nitrogen balance of ATW and FATW fed to captive sage grouse hens. �! ._ _j 13 Table 7. Analysis of covariance for effects of fert il izat ion treatments amounts of energy retained from sagebrush. df Source Energy intake (kcal) Treatment Intake x treatment Error MS 54618.71 19.6 7.6 424.0 1 1 1 16 £ value £ > £ 133.07 0.05 0.02 0.0001 0.8 0.9 on The apparent digestibility of dry matter also did not differ with respect to fertilization (Fig. 8) (£ = 0.30). FATW had a mean dry matter digestibility of 52.5% compared to 48.9% for ATW, but all birds did not retain the same proportion of ingested dry matter (£ = 0.05). Sage grouse trapping began in the first quarter of 1987 and continued through mid-May. Initial trapping success was poor but success rates improved later in the season (Fig. 9). The first bird was captured on 6 February. A total of 41 female sage grouse was outfitted with radios by the conclusion of the trapping season (Table 8, Appendix A). Yearling birds comprised the bulk of the radio-marked sample (73%). 60 HALES FEl1ALES 50 ~ ~ p:: I=> CJ D 40 E-< p." <: u 30 U) ~ p:: H ~ 20 ZI 10 1 2 FEB Fig. 9. 3 4 5 6 7 B 9 HAR WEEK-LONG TRAPPING 10 11 12 13 14 15 16 APR PERIODS Numbers of sage grouse captured during Spring 1987. HAY �14 SO r- • •• ATW ,.. 40 IFATW r\ 0 30 I- w Z '" •• '" « I;j a: ..• ,.. • 0> u JIll!.. 20 • l- 6 ,.. 10 l- a 20 • • • '" • ",'" • 30 40 CM 70 60 SO I NTAKE 80 90 (g) Fig. 8. Retained dry matter in relation to intake by captive sage grouse fed fertilized (FATW) and unfertilized (ATW) sagebrush. Table 8. Numbers of adult and juvenile female sage grouse fitted with solirpowered radio transmitter packages in North Park, Colorado, 1987. 1- 2+ n Area Fertil ized Lake John Totals n % % Totals 1 4 33 20 14 16 66 80 21 20 11 27 30 73 41 Total body mass of birds and weights of radio packages were similar from fertilized and unfertilized study areas (Appendix B). Radio packages were < 2% of total body mass. �15 Nesting success was higher among birds captured near the fertilized study areas than those captured in the unfertilized area near Lake John (E = 0.04) (Table 9). However, it is not know to what extent if any the fertilizer treatment had in producing this effect. As birds were marked in Spring 1987, the fertilized study areas were intensively searched for radio-marked birds. Three birds (of 21 trapped in the area) were within 1 km of fertilized plots. One of these (freq. 151.191) used the plots on the McCallum Oil Field (Area A) before breeding and then disappearing after a failed nesting attempt. Two other birds were captured during the laying interval in the fertilized study area south of JC 12, along JC 23A. Both birds successfully hatched eggs in nests on about 1 June. One bird (freq. 150.065) nested about 10 m from the fertilized plot at the western end of what is now the Perdiz Burn (Area C). This bird moved to meadow areas northwest of the nest site and disappeared about 2 weeks post hatch. The other bird in Area C (freq. 151.111) nested in the first fertilized plot south of JC 12. This bird hatched 6 eggs and spent much of the summer and fall within about 400 m of the nest site. Table 9. Nesting success (n successful nests/n birds in sample) of radiomarked sage grouse in North Park, Colorado, 1987. The data includes several birds for which reproductive status was not determined because of failure to detect radio signals. Treatment Adults Fertilized Lake John 4/6 W4 6/13 4/15 10/19 (52.6%) 4/19 (21.0%) Overall 4/10 10/28 14/38 (36.8%) Yearlings Totals Clutch sizes could be determined accurately for 9 hens after chicks left nests (Appendix A) and ranged between 6 and 7 eggs/clutch. Clutch size was not correlated with distance to fertilized plots (Rz = 0.05, E = 0.54) (Fig 10). One bird was located while renesting with a clutch of 5 eggs. I was unable to reliably determine the nesting success or clutch sizes of several birds (Appendix A). Reasons for not locating birds include radio failures, mortality, and bird movements outside the range of ground-based radiotracking.' Subsequent observations indicate that several birds moved outside the study area into Wyoming. Therefore, several "missing" birds could have nested successfully. By including only those birds with complete histories through the nesting season, the proportion of successfully nesting hens was 9/17 for birds from the fertilized areas, 5/13 for birds from the unfertilized area (X = 0.62, E = 0.43), and about 47% overall. Therefore, it is unclear if fertilization improved the nesting success of marked or unmarked birds in the northeast portion of North Park. No new leks were identified near the fertilized study areas in 1987. One small lek (Ram) was inactive and another (Hawk) became active with a peak attendance of 8 males and 9 females. Other leks in the northeast portion of Jackson County most closely associated with the fertilized study areas �16 / ) ·-~"'r' 8 I U 5 .....J .A. 1- • 2+ 7 U Z in 8w 6 .A. zl .A. • .A. 5 o 10 20 o I STANCE 30 Renest 40 (km) Fig. 10. Clutch size of 2 age classes of radio-marked sage grouse hens in relation to distance from fertilized study plots. (Perdiz, Turkey, and Denmark) did not show increased numbers of males/lek (Fig 11) . Results of analyses on soils were received and summarized. The control and treatment plots did not differ prior to fertilization in any of the parameters measured (Appendix C). Two soil series were represented in the plots fertilized in Fall 1987. The Morset loam series is a dominant soil type in Area C and composes a substantial portion of Area B. This series contained higher levels of organic matter, potassium, and copper than Bosler loam (Appendix C). Bosler loam is a major soil series in the Area A study area. Bosler loam contained more zinc than Morset loam. Browse transects indicated that sage grouse used the fertilized plots for feeding more than they use adjacent control plots; a this finding supported by the captive grouse experiments. The hypothesis that nitrogen fertilization will improve grouse habitat to the extent that reproductive success or survival will be improved is based on work with red grouse (Lagopus lagopus scoticus) (e.g., Miller 1968, Miller et al. 1970). Red grouse are strongly territorial and monogamous, whereas sage grouse are not. Also, sage grouse do not carryover large energy reserves to the breeding season (Remington and Braun 1988), thus, exogenous nutrient sources are likely more important to egg and chick quality than endogenous sources. Because red grouse are more predictable in space and time than sage grouse, it may be possible to treat specific areas and measure responses. Moreover, red grouse are more likely to �l7 1985 1986 1987 -r;;.~,. /" ~ ....-'. .. ~~~~~~~~--~~-~~~-"~"~~_=- -~ .. Cc~~~~·_- ~ Fig. 11. Peak counts of male sage grouse on strutting grounds in North Park, Jackson County, Colorado. Leks most closely associated with fertilizer treatments are in the northeast portion of North Park. �18 remain in the treatment area (unless the treatment is deleterious or the bird disappears for other reasons that are independent of the treatment) so that any cumulative effects of the treatment on egg/chick quality or adult and chick survival can be realized. In this study, explicit sage grouse nesting areas could not be identified for fertilizer treatment and radio-marked hens apparently did not preferentially use fertilized areas. Thus, there was no discernable experimental manipulation of the radio-marked birds. An alternative approach to conducting the field portion of the fertilization project could have concentrated trapping at 3-4 leks having relatively large expanses of adjacent nesting habitat. In a pre-fertilization field season, intensive sampling of hens at treatment leks could be done and their nesting areas identified. Fertilizer could be applied the subsequent fall to the nesting areas identified. Birds with active radios could be monitored throughout the winter to document use of treatment areas prior to fertilizer response. In spring, intensive trapping could be repeated at treatment leks. In this way a sample of grouse using fertilized areas could be obtained. The effect of different soil types on fertilizer response could be studied by applying fertilizer to much smaller plots distributed among soil types. A revised trapping procedure also may have been useful to overcome negative bias for hens of the spotlighting technique (Giesen et al. 1982). For example, during 1979 and 1980 male grouse were captured at a rate of 1.98/hr compared to 0.86/hr for females (Giesen et al. 1982) from the North Park population, which is assumed to have about twice as many females as males (Braun 1986). Perhaps by using cannon nets or drop nets during hen attendance peaks, large numbers of hens may be captured at treatment leks with disturbance potentially limited to a single trapping event. This method also might offer some assurance that radio-marked birds would nest in the vicinity of treatment leks (Braun et al. 1977). LITERATURE CITED Braun, C. E. 1986. Responses of sage grouse to vegetation fertilization. Job Prog. Rep., Colorado Div. Wildl. Fed. Aid Proj. W-37-R-38. Pp. 115-141. , T. Britt, and R. o. Wallestad. 1977. Guidelines for maintenance of ------sage grouse habitats. Wildl. Soc. Bull. 5:99-106. Bryant, J. P., F. S. Chapin, III, and D. R. Klein. 1983. Carbon/nutrient balance of boreal plants in relation to vertebrate herbivory. Oikos 40:357-368. Giesen, K. M., T. J. Schoenberg, and C. E. Braun. 1982. Methods for trapping sage grouse in Colorado. Wildl. Soc. Bull. 10:224-231. Horwitz, W., ed. 1980. Official methods of analysis of the Association of Official Analytical Chemists. Assoc. Off. Anal. Chern., Washington, D. C. 1018pp. Miller, G. R. 1968. Evidence for selective feeding on fertilized plots by red grouse, hares, and rabbits. J. Wildl. Manage. 32:849-853. �19 _____ , A. Watson, and D. Jenkins. 1970. Response of red grouse populations to experimental improvement of their food. Pages 323-335 in A. Watson, ed. Animal populations in relation to their food resources. Brit. Ecol. Soc. Symp. 10. Blackwell Scientific Publ., Oxford and Edinburgh. Mould, E. D., and C. T. Robbins. 1981. Evaluation of detergent analysis in estimating nutritional value of browse. J. Wildl. Manage. 45:937947. Remington, T. E., and C. E. Braun. 1988. Carcass composition and energy reserves of sage grouse during winter. Condor 90:15-19. Sibbald, I. R. 1979. Metabolizable energy evaluation of poultry diets. Pages 35-49 in W. Haresign and D. Lewis, eds. Recent Advances in Animal Nutrition--1979. Butterworth's, London, U.K. Van Soest, P. J. 1963~. Use of detergents in the analysis of fibrous feeds. I. Preparation of fiber residues of low nitrogen content. J. Assoc. Off. Agric. Chern. 46:825-829. _____ . 1963h. Use of detergents in the analysis of fibrous 'feeds. II. A rapid method for the determination of fiber and lignin. J. Assoc. Off. Agric. Chern. 46:829-835. _____ . 1982. Nutritional ecology of the ruminant. 0 and B Books, Inc., Corvallis, Ore. 374pp. Welch, B. L., and E. D. McArthur. 1986. Wintering mule deer preference for 21 accessions of big sagebrush. Great Basin Nat. 46:281-286. Prepared by: Approved by: ~~ Orrin B. MYS Graduate Research Assistant ~2' ~ Clait E. Braun Wildlife Research Leader �20 Appendix A. Nesting success of female sage grouse fitted with radio transmitters during winter-spring 1987 and status of radio packages as of 30 June 1987. Band Treatment # Age Fertilized 5895 5894 5899 5893 5896 5727 5721 5722 5849 5857 5858 5728 5898 5720 5892 5846 5856 5887 5855 5719 5763 5900 5743 5742 5847 5854 5882 5724 5890 5886 5744 5897 5885 5725 5881 5891 5723 5883 5889 5761 5884 Yrlg Yrlg Ad Yrlg Yrlg Yrlg Yrlg Yrlg Ad Yrlg Yrlg Ad Ad Ad Ad Ad Ad Yrlg Yrlg Yrlg Yrlg Yrlg Yrlg Yrlg Ad Yrlg Ad Yrlg Yrlg Yrlg Yrlg Yrlg Yrlg Ad Yrlg Yrlg Yrlg Ad Yrlg Yrlg Yrlg Control S Nesting success Clutch size fail ed ? {fail ed)" ? successful successful 6 7 ? successful failed successful successful 4+ ? (5+)b 7 ? successful successful fail ed successful fail ed successful fail ed successful failed fail ed successful 6 7 6 6 ? (3+) 7 ? ? (failed) ? (failed) ? ? successful successful ? (failed) ? ? ? ? ? fail ed successful 7 ? fail ed fail ed renest ? (fail ed) ? Presumed failed. b Number of chicks observed with hen. 5 Radio frequency 150.024 150.084 150.096 150.104 150.124 150.145 150.165 150.185 150.874 150.983 150.989 151.028 151. 034 151.107 151.111 151.191 151.232 151. 266 151. 308 151.373 151. 432 150.045 150.225 150.671 150.936 151. 051 151. 073 151. 088 151. 099 151.142 151.173 151. 206 151.212 151.251 151. 283 151.313 151. 326 151.344 151. 404 151. 423 151.447 Radio status active active recovered active active recovered active missing active active missing active active recovered active missing active active active active active active missing active active active active active active active active missing active active active missing active active active active missing �21 Appendix B. Sage grouse body mass and weight of radio packages from fertilized and unfertilized (Lake John) study areas in North Park, Colorado, 1987. 111 Treatment n x SE Body mass (g) Unfertilized Fertil ized 20 21 1525 1546 26.3 17.2 0.5229 Radio weight (g) Unfert ilized Fertil ized 14 20 29.5 25.7 1.5 1.3 0.0691 Radio/body (%) Unfert ilized Fertil ized 13 19 1.95 1.68 1.01 0.86 £ > �N N Appendix C-l. Soil characteristics of experimental plots when treated with ammonium nitrate fertilizer in October 1987. Condo (mmhosLcm) 6 6.8 0.18 6 6.7 0.15 > > 0.5 > 0.4 n Control Treatment £ > 111 pH OM (%) N03-N P Zn K Fe Mn Cu (ggm) 3.1 0.6 4.2 231 0.8 2.9 0.7 3.6 205 0.8 0.5 > 0.5 > 0.4 > 0.5 > 0.6 23.9 3.0 2.2 2.1 24.0 2.9 > 0.8 > 0.8 > 0.8 Appendix C-2. Soil characteristics of experimental plots when treated with ammonium nitrate fertilizer in October 1987. Soil series Bosler loam Morset loam E > 111 Condo (mmhosLcm) 0.10 4 6.7 0.20 8 6.8 > 0.5 < 0.01 < n pH OM N~-N P K 2.1 3.4 0.01 0.5 0.7 0.08 Zn Fe Mn Cu (ggm) (%) 3.5 140 4.2 257 0.4 < 0.01 0.9 0.7 0.02 1.8 17.9 3.1 2.3 27.0 2.9 0.10 > 0.5 < 0.01 �23 JOB FINAL REPORT Colorado State of: Project: W-152-R (01-03-045) Avian Research 15 : Job --- Work Plan: 3 Job Title: Sage Grouse Resource Exploitation and Endogenous Reserves in Colorado Period Covered: Author: 1 January 1984 through 31 December 1987 Jerry W. Hupp Personnel: D. A. Hein, D. J. Nash, R. A. Ryder, Colorado State University; M. Blymeyer, J. Capodice , T. Reed, Bureau of Land Management: J. Barry, C. Molitoris, W. Shuster, W. Wallis, E. Zieroth, U.S. Forest Service; C. E. Braun, C. Coghill, T. Henry, J. Houston, P. Mason, T. Sherrill, Colorado Division of Wildlife ABSTRACT Winter habitat use and foraging ecology of sage grouse (Centrocercus urophasianus) were studied in the Gunnison Basin, Colorado between 1985 and 1986. Sage grouse foraging activity (N = 157 feeding sites) was not proportionally distrubted (p < 0.001) among topographic features. Topographic distribution of feeding activity was influenced by physiographic variation in shrub structure of mountain big sagebrush (Artemisia tridentata vaseyana) relative to snow depth. Most foraging (45-64% of feeding sites) occurred in drainages and on southwest slopes where sagebrush exposure above snow was maximized. Sage grouse rarely foraged (1-4% of feeding sites) on northeast aspects with slopes >50 because exposed sagebrush was not widely available. Distribution of foraging was not influenced by topographic variation in crude protein or monoterpene concentrations of mountain big sagebrush. Within feeding sites, sage grouse did not selectively forage on plants with high crude protein or low monoterpene concentrations. Sagebrush structural characteristics at 87 winter feeding sites were compared to 100 random locations. Sagebrush structural measures were not useful to identify winter habitat in the mesic terrains where sagebrush removal is most likely to occur. Spring lipid reserves of adult male sage grouse were determined from carcass analysis of 96 individuals collected from 2 Colorado populations between 1983 and 1985. Spring lipid reserves were affected by winter severity. Males depleted lipid reserves during the courtship season. Males in Jackson County mobilized 125-130 g of fat during courtship while males in Gunnison County used an average of 66 g. Strutting display rates of adult males were quantified in Jackson and Gunnison counties in 1986. Slower display rates, lack of evening display, greater variance in male attendance at leks suggest �24 reduced energetic investment in courtship among males in Gunnison County. However, behavioral differences could not be attributed to unequal size of endogenous reserves as lipid deposits (N = 10 adult males/population) during early courtship were similar between populations in 1986. Lipid catabolism likely provides <10% of adult male energetic needs during courtship. Lipids may primarily be mobilized during early courtship when male displays are most vigorous due to the presence of females on leks, and when male reproductive success is determined. �25 RECOMMENDATIONS Habitat Management Recommendations 1. Sagebrush in drainages throughout the Gunnison Basin should be maintained as winter habitat. Treatment of sagebrush in drainages would have a disproportionately severe affect on winter habitat availability. In harsh winters when snow depths may exceed 50 cm, exposed sagebrush is primarily available in drainage sites. Removal of sagebrush at those sites would restrict sage grouse to other terrains where sagebrush forage could be buried by snow; reduced survival due to greater exposure to winter weather and predators is possible. There should be no treatment of sagebrush in drainages to insure that exposed sagebrush is available during severe winters. 2. Sagebrush on >50 southwest terrains as well as 0-50 high sites should not be treated. Southwest slopes are frequently used as winter foraging sites by sage grouse and sagebrush on that terrain should be maintained. Sagebrush canopy cover is sparse «20%) on southwest slopes and 0-50 high sites. Due to the xeric soils on those sites, livestock forage response would be minimal following sagebrush removal and would likely not justify treatment. No treatment of sagebrush on sites with less than 15-20% canopy has been recommended by other authors (U.S. Dep. Agric. 1969, Braun et ale 1977). 3. Limited treatment of 0-50 low terrains and slopes with northeast aspects would likely have minimal impact on sage grouse winter habitat. Sagebrush removal on those sites should not be complete. Live sagebrush should be, interspersed with treated areas to insure some shrub availability for sage grouse and other sagebrush obligates. Herbicide treatments in strips 30-50 m wide are preferable. Treated strips should be alternated with untreated strips in a 1:1 ratio. Repeated herbicide applications should not occur until recovery of sagebrush in treated strips is complete and structure is similar to adjacent untreated strips. Prescribed burning should not be conducted on 0-50 low sites or northeast slopes if fire cannot be contained within those terrains, or if removal of>50% of sagebrush within the treated terrain is likely. No treatments of 0-50 low or northeast slopes should occur if breeding habitats will be affected. 4. There should be no treatment of sagebrush within 1 km of any active sage grouse strutting ground in the Gunnison Basin. Maintenance of sagebrush within 1 km of leks insures that diurnal habitats required by male sage grouse during spring courtship will be available. 5. Breeding activity is not widely distributed in the Gunnison Basin. Areas within 3 km of Ohio, Tomichi, Quartz, and Razor Creek drainages may be important breeding areas due to the availability of irrigated hay meadows as summer habitats. Breeding activity in areas south and west of Gunnison may be limited because mesic summer habitats are not widely available. To insure that nesting habitats are available in the Gunnison Basin, there should be no treatment of sagebrush within 3 km of any lek that is near «3 km) floodplain boundaries of the Ohio, Tomichi, Quartz, or Razor Creek drainages. Maintenance of undisturbed sagebrush within 3 km of leks is consistent with recommendations suggested by the Western States Sage Grouse �26 Committee (Braun et al. 1977, Autenrieth 1981), and will help insure adequate availability of nest sites. 6. There should be no sagebrush treatment within 3 km of other major sage grouse leks in the Gunnison Basin that are >3 km from the Ohio, Tomichi, Quartz, or Razor Creek drainages. Major leks are those at which >20 males were observed displaying during at least 1 year between 1984 and 1986. These leks include Sapinero 1, Sapinero 3, and Upper South Parlin strutting grounds. 7. There should be no sagebrush treatment within 200 m of riparian areas with permanent streams, boundaries of irrigated hay meadows, spring developments, or livestock ponds. During summer months sage grouse use sagebrush habitats adjacent to these moist soil sites. Maintenance of sagebrush cover near moist soil areas may be necessary to sustain summer use of those sites. 8. Summer habitats in areas south and west of Gunnison could be improved by increasing availability of moist soil sites. Maintaining water flow in stream drainages during summer months would be beneficial. Placement of gabion structures and check dams could improve surface water availability in intermittent streams, increase soil moisture, and improve herbaceous growth in riparian areas. Removal of sagebrush to stimulate herbaceous growth is not a valid technique to improve brood habitat if it impacts nesting or wintering habitats. INTERAGENCY CONSULTATION 1. The CDOW should be responsible for monitoring the sage grouse population in the Gunnison Basin. District Wildlife Managers should conduct annual surveys of male sage grouse lek attendance on known leks. Lek surveys should be conducted between 1 April and 15 May and should begin as quickly as access to strutting grounds is feasible. Ideally, each lek should be surveyed a minimum of 3 times during the display season to obtain a representative evaluation of male display activity. Multiple visits are especially important in the Gunnison Basin due to the high degree of day to day variation in numbers of males that attend leks (Hupp 1987). Lek counts may not provide a reliable measure of annual fluctuations in the Gunnison Basin sage grouse population. However they do give an indication of the distribution of breeding activity in the Gunnison Basin. Long term changes in numbers of males that attend a specific lek may indicate habitat related changes in breeding activity in local areas. Results of annual lek surveys should be summarized, recorded, and forwarded to local offices of the BLM, USFS, and SCS. 2. CDOW personnel should continue to search for undiscovered or newly formed leks throughout the Gunnison Basin. This study suggests that little breeding activity occurs in areas southwest of Gunnison and north of Blue Mesa Reservoir. Searches should continue to be conducted within those areas to confirm whether breeding activity is limited. Searches for leks would be most productive in early April because males remain on leks for longer periods during the early display season (J. W. Hupp, unpubl. data). Searches conducted in late April and May would be less likely to �27 locate leks because males display for shorter periods during morning hours. Lek locations should be confirmed during multiple visits in the year following discovery. Locations of discovered leks should be marked on 7.5-minute topographic maps upon confirmation. Copies of maps with discovered leks as well as numbers of observed males should be forwarded to local offices of the BLM, USFS, and SCS. 3. CDOW personnel should continue to monitor the sage grouse harvest in the Gunnison Basin through collection of wings from hunter-harvested birds. Wing barrels have proven to be an efficient technique of collecting large samples of wings. Placement of wing barrels prior to the opening of the sage grouse season should continue. Examination of wings provides information on age and sex structure of the fall population. While population trends cannot be evaluated from these data, age and sex ratios do provide information on reproductive success during the previous breeding season. Reproductive success can affect rates of population growth, and should be monitored. Collection of wings at wing barrels also provides information on distribution of hunting success in the Gunnison Basin as well as data regarding the timing of harvest. Reports of hunter harvest and sex and age structure of the sage grouse fall population should be reported to local offices of the BLM, USFS, and SCS. 4. Federal agencies should provide the CDOW with information regarding proposed sagebrush treatments. Information supplied to the CDOW should include (1) a 7.5-minute topograhic map with boundaries of the treatment area clearly defined, (2) information on the method and season of the proposed treatment, and (3) locations of previous sagebrush treatments that have been completed during the previous 10 years within 1 km of boundaries of the proposed project. The CDOW should be notified immediately when a treatment proposal is developed within a federal agency. Advanced notification should allow CDOW District Wildlife Managers and federal agency wildlife biologists adequate time to search for sage grouse leks within 3 km of boundaries of the proposed treatment during the breeding season (1 Apr to 15 May) prior to implementation of the project. Treatment boundaries should be adjusted or the treatment postponed for a year if any sage grouse display activity is observed within 3 km of the project boundaries. Numbers of males that attend discovered leks near proposed treatments should be assessed during mUltiple visits ~3) in the year following discovery. If the discovered lek is (1) within 3 km of the Ohio, Tomichi, Quarta, or Razor Creek floodplains, or (2) attended by large numbers (~20) of males, then the planned treatment should be cancelled, or the boundaries adjusted so that no treatment occurs within 3 km. If the numbers of males observed on leks in the year following discovery is small ~20) and the lek is not within 3 km of the Ohio, Tomichi, Quartz, or Razor Creek floodplains, then treatment to within 1 km may be permissible. 5. Definitions of potential climax plant communities on mountain loam and dry mountain loam sites should be re-evaluated to determine the validity of sagebrush removal to improve "range condition." Federal agencies should evaluate pre- and post-treatment vegetative composition at sagebrush treatment sites. Canopy cover or biomass of shrubs (by species), grass, and forbs should be estimated at sample sites within treatment areas. Sampling should be of sufficient intensity to construct adequate �28 confidence intervals on pre- and post-treatment vegetation composition, and to draw valid inference conclusions on treatment effects within the project area. Post-treatment sampling should occur periodically during 10-15 years to evaluate long-term effects of treatment and to evaluate recovery time of shrubs. Ideally, monitoring should occur concurrently on ~ nearby untreated control area. Reports of treatment effects on plant species composition should be provided to the CDOW. �29 ACKNOWLEDGMENTS This study was supported Additional Bureau technical and Colorado landowners encouragement develop was a constant Nash comments source Service, program, deal of assistance of information by the U. S. U. S. Forest access to ranchers to private for his support scientist on my graduate natural Groshek, cheerful lands and for challenging with my academic and expertise. and and and professional. committee during My deepest The support of Mike thanks management and Cliff Reynolds and friendship, A special resource to this project. assistance conditions. support were provided for providing my doctoral of Wildlife. me to Dr. Ronald program and Drs. Dale Hein and provided and many useful on my dissertation. contributed Barbara Division I am grateful to Dr. Clait Braun a great served Numerous Basin thanks Basin fully as a wildlife provided Donald State University. throughout more support Soil Conservation in the Gunnison My special Ryder and logistical of Land Management, Service, by the Colorado My sincere friendship, and for sharing management. The assistance his under for his unselfish insights and friendship difficult this study. acknowledged. assistance on wildlife and conservation of District and for his in suggesting is gratefully Griffin, competent, also to Joe Capodice and Terry Reed to Jim Houston to Robert of field research and for his initiative Blymeyer thanks in the Gunnison for their dedicated, long hours appreciation professionals Wildlife and Managers �30 Cliff Coghill, Tom Henry, Phil Mason, and Tom Sherrill appreciated. My thanks also to Jim Olterman and Rick Sherman for their support and interest. Wallis, Jim Barry, Carol Molitoris, stages of the study. allowed me to use Soil Conservation I am deeply grateful for sharing regarding sagebrush Rick Hooley, and Tom Washburn aspects of laboratory Chapman provided consultation Diane Hall provided I am especially Department excellent grateful secretarial their discussions Biology of biological assistance analyses. Jann Black and assistance. in the Biology for their friendship issues. and for Thanks also to Fishery and to make my doctoral experience. Finally, my deepest appreciation Hupp for their unconditional I have worked analyses. David Bowden and Phil faculty and staff for helping a rewarding laboratory t~ my fellow graduate students of Fishery and Wildlife and Thanks also to Joan also provided analysis. on statistical and Lynn Stevens chemical analysis, support. and Carol Ann We inland for conducting with various program Service snow mobiles. a great deal of laboratory Rick Bettinger, support Ken Lair and John Scott graciously to Don Dick, Tom Remington, their knowledge for providing Wildlife Bill Shuster, Bill and Elaine Zieroth of the U. S. Forest Service provided during various Demander is deeply to my parents, ~ayne and Betty love and support throughout towards my college degrees. the years that �31 TABLE OF CONTENTS ABSTRACT OF DISSERTATION iii ACKNOWLEDGMENTS -.......................... v LIST OF TABLES. .................................................... ix LIST OF FIGURES Chapter 1. xi SAGE GROUSE WINTER HABITAT USE AND FORAGING IN THE GUNNISON BASIN, COLORADO ECOLOGY Introduction. ................................................. 1 Study Area. ................................................... 3 Methods. ...................................................... 7 Topographic Distribution 7 Shrub Structure 10 Sagebrush 11 Chemical Analysis Results 14 Snow Depth Variation Topographic Sagebrush 14 Distribution Composition of Feeding Sites and Structure Chemical Variation Among Random Collection Sites 24 Foliage Chemical Differences Between Browsed Unbrowsed Sagebrush Plants Discussion 16 29 and 31 31 Sage Grouse Habitat Use 31 Sage Grouse Forage Selection 37 Management Implications 41 �32 Literature Chapter 2. Cited 43 ENDOGENOUS RESERVES AND COURTSHIP OF ADULT MALE SAGE GROUSE BEHAVIOR Introduction " Methods 48 49 Phase 1: Male Endogenous Reserves During Spring Courtship. ...................................... 49 Phase 2: Endogenous Reserves and Courtship Behavior ..... 52 Results 55 Phase 1: Male Endogenous Reserves During Spring Courtship.............................. Phase 2: Endogenous Reserves and Courtship ......... 55 Behavior ..... 58 Discussion 62 Sage Grouse Body Mass 62 Lipid Depostion 62 and Winter Severity Lipid Reserve Use During Courtship Male Display Rates a-q_dLipid Reserve The Adaptive Significance Literature Cited 76 Size of Male Lipid Reserves 65 67 69 �33 LIST OF TABLES 1.1. 1.2. 1.3. 1.4. 1.5. 1.6. 2.1. 2.2. 2.3. 2.4. Categories of slope and aspect used to classify terrain in randomly-selected sage grouse survey plots, Gunnison Basin, Colorado -....................... Gas chromatograph programming specifications used separate and quantify monoterpenes in Artemisia tridentata vaseyana and b. nova foliage from the Gunnison Basin, Colorado 8 to 14 Observed and expected distribution of sage grouse feeding sites among terrain categories in the Gunnison Basin, Colorado, 1985-86....................... 21 Big sagebrush structural characteristics at random and sage grouse feeding sites in the Gunnison Basin, Colorado, 1985-86....................................... 26 Chemical characteristics of big sagebru~h leaves collected at 32 random sites in 4 terrain categories (8 sites/category), Gunnison Basin, Colorado, March April 1986 -................................. 30 Chemical characteristics of leaves of browsed and unbrowsed big sagebrush plants at sage grouse winter feeding sites (N = 20), Gunnison Basin, Colorado, January -March 1986..................................... 32 Differences in sage grouse physical characteristics among years and between courtship periods (2-way ANOVA), Gunnison and Jackson counties, Colorado, 1983-85 . 56 Physical characteristics of adult male sage grouse during courtship in Gunnison and Jackson counties, Colorado, 1983- 85 . 57 Peak daily attendance of adult male sage grouse at 3 leks in Gunnison and Jackson counties, Colorado. Surveys were conducted during 5 mornings on each lek, April-May 1986 . 61 Winter (Nov-Mar) snowfall and mean temperature departure from 30-year average in Gunnison and Jackson counties, Colorado, 1983-86. Lipid reserves of adult male sage grouse during early courtship following winter . 63 �34 LIST OF FIGURES Figure 1.1. Gunnison 1.2. Mean winter (1 Jan - 15 Mar) snow depths within terrain categories in the Gunnison Basin, Colorado, 1985-1986............................................... 15 Distribution of l-km random survey plots in the Gunnison Basin, Colorado, 1985. Solid circles indicate survey plots with sage grouse feeding sites................................................... 17 Distribution of I-km random survey plots in the Gunnison Basin, Colorado, 1986. Solid circles indicate survey plots with sage grouse feeding sites................................................... 19 Observed and expected proportions of sage grouse winter feeding sites within terrain categories in the Gunnison Basin, Colorado, 1985-86. Confidence limits (95%) for observed use ·were calculated following Byers et al. (1984). Failure of an expected proportion to fall within a confidence limit indicates that feeding activity was different (E < 0.05) than expected.. ......................................... 22 Mean sagebrush height at feeding and random locations relative to snow depth within terrain categories in the Gunnison Basin, Colorado, 1985-86 34 2.1. Colorado 50 2.2. Strutting display rates (R ± SE.) of adult male sage grouse in Gunnison and Jackson counties, Colorado, April-May 1986.......................................... 1.3. 1.4. 1.5. 1.6. Basin, study Colorado................................ areas.................. .................. 4 59 �35 CHAPTER 1 SAGE GROUSE WINTER HABITAT USE AND FORAGING IN THE GUNNISON BASIN, COLORADO ECOLOGY INTRODUCTION Sage grouse dependence documented 1975). (Patterson Sagebrush wildlife To develop guidelines emphasized Previous measurement Beck 1977, Connelly Colorado assessments dependent on sagebrush of shrub structure (e.g., sagebrush 1982). More recently, in sagebrush have height, at use sites (Eng and Schladwieler 1982, Schoenberg for snow may limit shrub of sage grouse winter habitat based on taxonomic variation 1972, Remington in northern crude protein and content. Quantitative useful are of particular (1985) assessed winter feeding site selection monoterpene 1967, Higby for habitat maintenance, Winter habitats sage grouse are completely canopy cover, and density) and Braun to improve grass (Schneegas forage and cover during that season, and because availability. et al. have described biotic and abiotic characteristics of areas occupied by sage grouse. interest because 1972, Wallestad from attempts impact sage grouse habitat 1975). biologists for forage and cover is well 1952, Eng and Schladweiler removal resulting forage may severely 1969, Wallestad upon sagebrush descriptions in development of sagebrush of guidelines shrub structure for maintenance have been of winter habitat �36 (Braun et al. 1977, Autenrieth structure criteria vegetation applied in habitat evaluation sampling. to describe Other assessment species composition is available. topographic terrains. 1982). feeding physiographic distributed sagebrush structure, structural 1972, Beck in snow depth, or foliage chemistry. of sage grouse winter of southern Colorado between 1985 that sage grouse feeding sites were topographic or foliage chemistry of foraging activity. at winter variation among available physiographic was to evaluate whether structure topographic charact~ristics objective distribution in areas studies of sage grouse shrub structure, I tested the hypothesis proportionally (Winward and (Eng and Schladweiler However, previous sites in the Gunnison-Basin and 1986. features and Sage grouse use of sites with destinctive species composition, I evaluated structure of sage grouse winter habitat winter habitat have not quantified sagebrush criteria may be more easily Because sagebrush features has been observed 1977, Schoenberg intensive criteria could be useful to assess and distribution with heterogeneous use of shrub often requires are affected by physiographic 1977), topographic availability However, areas of sage grouse winter use and identify sites where winter habitat Tisdale et al. 1982). variation influenced I measured features. My in snow depth, topographic sagebrush shrub feeding and random sites to learn if distinctive characteristics of feeding areas existed. whether sage grouse selectively protein or low mono terpene concentrations I also evaluated foraged on sagebrush plants with high within feeding sites. �37 STUDY AREA The Gunnison (Fig. 1.1). Basin is an intermontane Elevation basin in southern Colorado in the study area is between 2,300 and 2,900 m. The Basin is semi-arid with a mean annual precipitation Gunnison. winter Approximately snowfall temperatures Oceanic 48% of the annual precipitation (Hunter and Spears 1975)-. Winters between -13 and 1 C from January and Atmospheric of 28 cm at Admin. 1986). occurs as are cold with mean through March (Natl. Snow cover typically persists through March. The Gunnison alluvial Basin is topographically diverse. flood plains are adjacent to major streams. plains occur at the mouths of tributary drainages. Steep-sloped are highly dissected by permanent irrigated and intermittent Shallow, eroded gulches are common on upland slopes. Soils and vegetation Alluvial Uplands are mesas with broad, flat tops occur in several areas of the Uplands streams. Level outwash to steeply rolling with slopes ranging from 5 to 300. moderately Basin. Broad (> 2 km) in the Gunnison Basin are also diverse. soils in flood plains are poorly drained and are used as grass hay meadows and pasture. well-drained soils derived from weathered (Hunter and Spears 1975). Upland sites are xeric with igneous and metamorphic Surface horizons rock of upland soils are fine grained or gravelly and stony loams. Mountain big sagebrush was the dominant upland vegetation. big sagebrush (~. ~. tridentata) wyomingensis) were not found in the Gunnison taxonomic classification classification and Wyoming big sagebrush Basin. follows Winward and Tisdale of big sagebrush herbarium Basin (~. ~. Big sagebrush (1977). Taxonomic specimens was confirmed by �38 0 C <t 0: 0 ...J 0 0 • ~ •••• rJ) .•. cr w •... ~ "'w -~-' NO o i g~ §~ S {J ~ ~. ~I\ ,0· Illl~ • I L ----- cr. _ �39 the U. S. Forest Service Shrub Science Laboratory pers. commun.). Growth forms of big sagebrush were highly variable and dependent on xeric south slopes was short cover < 20%), while sagebrush and vigorous (canopy cover> common on xeric ridgetops occurred were interspersed (Chrysothamnus dominated Quaking « 35 cm) and widely 30%). Black sagebrush and south slopes. and mountain with sagebrush viscidiflorus) snowberry occurred distributed bottlebrush above 2,900 m. Douglas (A. ~) bitterbrush oreophilus) rabbitbrush shrub that often had been removed. included western wheatgrass squirreltail (Pseudotseuga and Sandberg bluegrass (Eriogonum spp.), cinquefoil (Agropyron prairie in smithii), (Stipa comata), junegrass (Poa sandbergii). (Castilleja (Potentilla lupine (Lupinus argenteus), grasses needle and thread (Sitanion hystrix), forbs included paintbrush spp.). was (Symphoricarpos Common understory understory (Astragalus Antelope and Douglas-fir (Festuca arizonica), (Koeleria cristata), silvery tall (> 50 cm) (A. ~) was a common understory overstory (canopy on isolated mesic sites below 2,900 m, and were communities fescue spaced Silver sagebrush at some sites. Basin Big sagebrush on mesic sites was usually aspen (Populus tremuloidies) sagebrush Arizona on site conditions. sites where the sagebrush menziesii) widely in the Gunnison at a few mesic locations below 2,900 m. (Purshia tridentata) (E. D. McArthur, Common spp.), buckwheat spp.), Phlox spp., common fleabane (Erigeron Plant names follow Scott and Wasser spp.) and vetch (1980). �40 METHODS Topographic Distribution Ground searches between 3 January chosen throughout were established 7.5-minute winter for sage grouse feeding sites were conducted and 15 March in 1985 and 1986. Random points were the Gunnison plots around each point. topographic and searched rugged maps. (l-km diameter) of plots were drawn on Circular plots were visited features characteristics topography Boundaries on foot for feeding sites. the field by comparing terrain Basin and circular illustrated Plots were located in on topographic in the area to be surveyed. of the Gunnison once each Basin, boundaries maps with Because of the of survey sites were easily discerned. Terrain within each random survey plot was classified aspect (Table 1.1). level to verify categories Where necessary I used a compass slope aspect ~nd steepness. were drawn on topographic on foot for feeding sites. obtained at 5 points spaced at 50-m intervals category. detecting terrain Ideally, transects terrain Measures of snow depth were along transects However, of terrain categories, Therefore, of for each due to the high maintenance of straight Also, feeding sites in one topographic were often discovered type. assessed in each to do so were made using line (Burnham et al. 1982) in 1985. lines was not feasible. of terrain search effort and the likelihood Initial attempts degree of interspersion category Boundaries use sites would have been independently category. and an Abney maps and each terrain type was searched terrain by slope and when an observer was in a different it was not possible to measure search effort �41 Table 1.1 Categories of slope and aspect used to classify terrain in randomly selected sage grouse survey plots, Gunnison Basin, Colorado. Terrain 1. a - category Site description 50 slope, Areas of < 50 slope,broad low topography outwash plains adjacent topography,terraces 2. a - 50 slope, high topography Drainage to areas of higher on slopes. Areas of < 50 slope,broad ridge tops topographically surrounding 3. (> 100 m) flood or Narrow « (> 100 m) mesa or higher than terrain. 100 m) flood plains of permanent intermittent streams, shallow eroded gulches on slopes. 4. > 50 slope, Slopes> 50 with south or west aspectsa. Slopes> 50 with north or east aspectsb. southwest 5. > 50 slope, northeast aAspects with bearings of 136 to 3150. bAspects with bearings of 316 to 1350. and �42 independently searched for each terrain category. such that all terrain categories Feeding in snow. Track observation throughout flushed. Therefore, site terrain features were classified categories (Table 1.1). overlapped 2 terrain categories. On a few occasions, was assigned to the terrain take place. Because 1 foraging observations, terrain discovered feeding feeding large feeding sites « the observation activity appeared it was possible to To improve independence of site was not included in the analysis to of 200 m) to a previously site in the same plot. Discovery of adjacent sites rarely occurred. I used chi square analysis site distribution availability. field surveys pooled to 1 of 5 possible in which most foraging if it was close to At each sage grouse When that occurred, area within a plot. and then and it was possible feeding sites were discrete, a feeding distribution lande4 at a site, foraged, of most feeding areas. snow Track observations feeding sites were discrete the boundaries as well as tracks of use because each winter period. that sage grouse usually observe> were sampled. was a valid criterion indicated feeding each survey plot was sites were located from flock sightings cover was present identify Instead, among terrains Although was made between distribution Expected 7 terrain categories were identified categories 6-150 and> to during as either 6-150 or > 150), I in some terrain categories due to bias associated in some terrain that feeding in 1985 and 1986 was proportional (slopes were classified observations was necessary to test the hypothesis during analysis. with small numbers (Alldredge and Ratti 1986). This of observations No distinction 150 slopes during analysis and among 5 terrain categories use was based on a uniform (Table 1.1) was tested. distribution of feeding activity �43 across all terrain categories within survey plots where feeding activity was observed. not considered categories in calculation was estimated (95%) were calculated each terrain category. proportions differed Terrain categories in unused survey plots were of availability. from topographic Availability maps. Confidence for the observed proportions Confidence of terrain limits of total use within intervals were compared to expected to evaluate whether observed use of a terrain category from expected use (Byers et a1. 1984). Shrub Structure Shrub structure was measured sites. at a sample of sage grouse feeding Sites selected for measurement where approximate boundaries structure was not measured of the use area could be discerned. snow, or where feeding activity was not A 15-m tape was placed in a north-south center of the foraging area. transect was recorded direction Species of each shrub beneath and sagebrush was classified measurements shrubs beneath included axis of crown, (4) height the tape were measured. (1) length of transect (3) crown width perpendicular Canopy dimensions Individual intercept, shrub (2) longest to the longest axis, and Live sagebrush plants within 0.5 m of the 15-m transect were counted to obtain an estimate of density. crossed the from ground level to the tallest stem (excluding inflorescenses). dimensions over the as living or dead. Dead shrubs had living foliage on < 20% of stems. of individual Shrub at sites where sage grouse tracks were obscured by melted or windblown apparent. of shrub structure were those and density were measured Shrub along a 2nd, ls-m transect the center of the 1st line at a perpendicular angle. that �44 Shrub structure Gunnison Basin. was also measured Random sites were stratified in each of 5 terrain catagories within (Table 1.1). with 20 locations sage grouse winter distribution transects sites. were oriented Measurement followed of shrub structure the same procedures Summary statistics Summary values that was intercepted height of live big sagebrush (3) the standard proportion were selected assessment Connelly assumptions among variables plant height as a for height), (density). they have previously and These variables been used in (Eng and Schladweiler was examined. 1972, I used analysis of no shrub structure and between differences random and feeding sites. by Ko1omogorov-Smirnov of normality (mean 1982). to test hypotheses Sagebrush p1ants/m2 (2) the mean the transects of variation of sage grouse winter habitat were evaluated (canopy cover), of big sagebrush (coefficient for analysis because categories, at random sites for each use and random plot. plants beneath deviation 1982, Schoenberg variance at random used at sage grouse feeding sites. of live sagebrush Correlation Two, 15-m directions and density by transects of mean height (4) the number use. (1) the total length of live, big sagebrush canopy height), east-west were calculated included survey plots used to and habitat in north-south, sampled Sites were selected a random sample of the same 1-km diameter evaluate terrain at 100 random sites in the distribution of among All data tests to insure that were met (Conover 1980:357). Chemical Analysis Sagebrush for analysis foliage was collected of crude protein at 20 winter and monoterpene sites were located while searching feeding sites in 1986 content. l-km diameter Winter survey plots. feeding �45 Sagebrush foliage was collected their discovery. boundaries Sagebrush at winter feeding sites at the time of foliage was collected of the feeding area could be discerned. shrub structure measurements were obtained in the Gunnison an adequate Basin were often narrow sample of browsed plants Therefore, Sage grouse feeding sites S m) and linear. a perpendicular angle. shrub canopy dimensions The 2nd line crossed Snow cover beneath along the axis the birds the center of the 1st at transects was removed, and density were measured. each transect were examined for evidence woody material. leaves. from sagebrush browsed and unbrowsed these were not available sample was individually sealed in a plastic bag and frozen. samples were also obtained during March and April 1986. each of 4 terrain categories (0-50 low, 0-50 plant. plants that were totally covered by snow because Sagebrush if ~ 2 Leafy stems were collected from several areas of the crown of each browsed Samples were not obtained by the dark, exposed Plants were considered leaves had been clipped by sage grouse. plants and do not conswne Browsed plants were distinguished of clipped Sagebrush and of feeding activity. Sage grouse feed only on the leaves of sagebrush occurred To obtain (N ~ 10) at a feeding site, it was 1 transect was oriented traveled while feeding. mesophyll samples and to sample sagebrush plants along the path of feeding activity. beneath « Foliage along 2, lS-m transects located near the center of the feeding area. necessary only if approximate to sage grouse. at 32 randomly Sagebrush was collected located Each sites from 8 sites in where sage grouse foraging primarily high, drainage, > 50 southwest). Sites were located in the same l-km plots used to evaluate winter distribution habitat use. were obtained Sagebrush foliage and shrub measurements and �46 along 2, lS-m transects east-west). Foliage I obtained and unbrowsed feeding site. samples. site. bagged plants for each sagebrush Equal amounts of leaves (1 g minimum) and frozen. by grinding facilitate fragmentation Monoterpenes were extracted ether through apparatus. ether. prior to grinding to loss of monoterpenes. dripping in flasks and saved. was added and the volume' increased Approximately Liquid for 6 hours in a Soxhlet The extract was captured (0.625ug/ul) from each random from samples by continuously 5-g subsamples in pooled leaves in a mortar. immediately and to prevent a were picked from plants so that all plants were equally represented was added to the mortar standard (north-south, species within Pooled samples of leaves were also prepared nitrogen diethyl directions samples were individually Samples were homogenized diethy1 in cardinal a 15-30 g pooled sample of leaves from each group of browsed individual oriented 20-ml subsamples A carvone to 100 ml with of extract were retained for analysis. I used a Perkin-Elmer ionization Extract detector samples Individual to separate with a hydrogen and quantify monoterpenes (4 ul) were carried monoterpenes Identification gas chromatograph flame (Table 1.2). through a 30-m tubular column. were identified was made by comparison using mass spectrum to published analysis. spectral patterns (Epstein et al. 1976, Heller and Milne 1978). Approximately samples 5 g of homogenized for analysis unbrowsed plants. matter percentages microkjeldahl multiplied of crude protein leaves were retained in random site, browsed, Samples were freeze-dried were determined. procedures from pooled Nitrogen (Horowitz 1980). by 6.25 to obtain an estimate to remove moisture and and dry content was evaluated Nitrogen content was of crude protein. by �47 Table 1.2. Gas chromatograph programming specifications used to separate and quantify monoterpenes in Artemisia tridentata vaseyana ~. ~ foliage from the Gunnison Basin, Colorado. Carrier gas Helium Flow rate 1.5 ml/min Initial temperature 70 C Initial rate of temperature increase 130 C Final rate of temperature increase 20 C/min Post temperature The hypotheses 300 C of no differences and total monoterpene tests dependent crude protein, at feeding analysis in mean crude protein, pooled individual among random sites in different of variance upon normality. and total and individual not differ between plants contents were tested with analysis nonparametric (approximate) 2 C/min Final temperature categories and or Kruskal-Wallis The hypotheses monoterpene samples of browsed terrain that concentrations and unbrowsed did sagebrush sites were tested with ~ tests or Mann-Whitney dependent upon normality. RESULTS Snow Depth Variation In both years snow depths increased and decreased low sites, in March and> (Fig. 1.2). 50 northeast between January Snow was deepest aspects. and February, in drainages, Snow was shallow on > 50 0-50 �48 1985 - 40 o • 5 NORTI-£AST ~ ~ 30 :c ra... ~ 20 ~ o z 10 Cf) o • 5 °SOUTHWEST JAN FEB MAR 1986 50 -t5 40 :c ._ .._ ..-.._--_ .._-_ ..-..,.., /«0<""- ------- --; r- a... 30 :>:: -~:~_~::>'" UJ ....... , o ~ o z o • 5 NORn-EAST ~ 20 ",", 0-5°LOW ........... ". DRANAGE Cf) -. O-t HGH o • 5 SOUTHWEST o JAN FEB MAR Fig. 1.2. Mean winter (1 Jan - 15 Mar) snow depths within terrain categories in the Gunnison Basin, Colorado, 1985-86. �49 southwest January on 0-50 high sites. slopes while depths were intermediate - March precipitation averages for the Gunnison in 1985 and 1986 was similar Basin (Natl. Oceanic to 30-year and Atmospheric Admin. 1986). Topographic Distribution Ground searches of Feeding Sites for sage grouse feeding sites were conducted in 142 and 120, l-km diameter survey plots in 1985 (Fig. 1.3) and 1986 (Fig. 1.4), respectively. I observed 74 winter feeding sites within used survey plots in 1985 and 83 feeding sites within plots in 1986. Analysis of sage grouse distribution features was not accurate not provide combined if flock sightings similar estimates track and flock sightings There was no difference similar estimates observations Feeding often foraged respectively), although - for analysis Thus, each sighting of topographic in either winter in drainages (Fig. 1.5). track and flock was valid. (l < 0.001) distributed (Table 1.3). A high proportion on use was proportional sites) provided Sage grouse (23-33% of feeding sites in 1985 and 1986, sites also occurred of feeding of track and flock distribution even though that terrain category low sites was greater of analysis. criterion use, and combining did I the distributions distributions activity was not proportionally the survey plots feeding and track observations and compared in topographic of topographic among terrain categories among topographic among terrains with chi-square (0.25 > l > 0.10). sightings 52 used survey of use among terrain categories. 1985 and 1986 observations 51 comprised only 3-4% of (23-42%) of sage grouse > 50 southwest slopes in each year, to availability (Fig. 1.5). Use of 0-50 (37% of feeding sites) in 1985 than in 1986 (11% (Fig. 1.5). Feeding activity (11-16% of feeding �Vl o ~ A\ o 1 2 3 .• 5 KILOMETERS 0 • 0 I 0 0 0 0 0 • • • • 0 0 . • • • 0 0 - • • 0 Oorl'':.I."t o Fig. 1.3. Distribution of l-km random survey plots in the Gunnison Basin, Colorado, 1985. circles indicate survey plots with sage grouse feeding sites. Solid �.N' ~ 012345 KILOMETERS 0 ~-\\ ~ '\ o~ tr_ 0 I 0 • 0 • • =v-:» • • • • Parlin • 0 0 0 0 ~ 0 • o ~ 0 0 0 Dorle~1I e • o ~ Fig. 1.4. Distribution of l-km random survey plots in the Gunnison circles indicate survey plots with sage grouse feeding sites. Basin, Colorado, 1986. Solid \.Jl I-' �52 Table 1.3. Distribution of sage grouse feeding categories in the Gunnison Basin, 1985-86. sites among terrain 1986 1985 Terrain Observed Expected Observed Expected o - 50 low 27 17.2 9 15.9 o - 50 high 12 14.1 9 13.0 Drainage 17 3.0 27 3.9 > 50 southwest 17 16.1 35 25.6 > 50 northeast 1 23.6 3 24.7 Total X2 92.9 fa < 0.001 aprobability expected 74 that the observed distribution. 83 163.5 < 0.001 distribution is similar to the �53 0- 5°LOW 0.5 z 00.4 I- ex: ~96" t=~ 0.3 00.3 Q. o ex: 0.2 Lower 95" Q. coo1\dence .,.. 0.1 0.1 1985 o 1986 z o z 00.4 0.4 lCC 0.3 i= ~ 0.3 Q. 1 00.2 40.19 16 0.1 0. 1985 o. z )5 0.16 8: 0 23 0. O~f 0.33 0.1 ·00.05 00.04 1985 1986 1986 ° SOUTHWEST 1 0.3 0.2 0.2 0.5 ~ 0.4 g: q; 0.11 o Q. o 0.5 0 ex: 0 a. DRAINAGE 0.5 0.5 ex: a. Expected jX'oportion 0.42 )5 ° NORTHEAST Z 0.4 0 0.31 i= CC 0.3 0 Q. 0 . 0.22 00.32 00.30 0.2 CC a. 0.1 0.04 0.01+ 1985 1986 1985 1986 Fig. 1.5. Observed and expected proportions of sage grouse winter feeding sites within terrain categories in the Gunnison Basin, Colorado, 1985-86. Confidence limits (95%) for observed use were calculated following Byers et al. (1984). Failure of an expected proportion to fall within a confidence limit indicates that feeding activity was different (f < 0.05) than expected. �54 sites) on 0-50 high sites was proportional I observed aspects little (1-4%) feeding activity even though that terrain category survey plots Sagebrush sagebrush sites in different were apparent terrain categories. It was the dominant it was present. 50 southwest and northeast black sagebrush sagebrush (R - 35 cm, SE - 1.8). The closest variables provided of big sagebrush described provided stands. coefficient of variation in between with each other. canopy cover and (£ indicated weak correlations variable measured of overhead Mean plant height was a measure The coefficient structural < 0.2) different Canopy cover was a measure of sagebrush Of the 4 sagebrush was rarely present correlated in plant size relative an evaluation on some terrain categories. by big sagebrush. plant size. variation black (R - 20 cm, SE - 1.0) than big Black sagebrush Each structural of sagebrush concealment However, was also present were not strongly Other comparisons among variables. dominated On sites where both species (£ - 0.56) occurred association mean height. sites. was shorter the mesic 0-50 low and drainage Structural selected species at 9 of 13 0-50 high sagebrush Black sagebrush occurred, components Big sagebrush in (present at 13 of 20 random sites) on xeric 0-50 was abundant sites where 30-31% of the among randomly 50% of shrub canopy cover) most sites. high sites. xeric> comprised Among Terrain- Categories.--Differences species composition sagebrush on > 50 slopes with northeast and Structure Site Variation (comprised> (Fig. 1.5). (Fig. 1.5). Composition Random to availability of variation to the mean. for height Density dispersion. variables analyzed, for height was similar only the (f - 0.71) among random �55 sites in different differences terrains (Table 1.4). in canopy cover, mean height, random sites were rejected Big sagebrush 53 cm) than plants (R 32%) was greater and sagebrush in other terrain categories, 50 northeast than plants on 0-50 high sites and> canopy cover at 0-50 low sites to drainages. 50 southwest (R - southwest and 0-50 high sites sagebrush canopy cover in those catgegories respectively) relative Sagebrush density drainages and> Comparison did not occur. 50 southwest slopes. sites was sparse 29 and 31 cm, respectively). was sparse similar estimates Big (R - 16% and 12% to density Between Years.--Feeding at sites where foliage was collected line transect orientation measurements that different of shrub structure structure was calculated regardless of transect in sites. replicate sites indicated (R - on > 50 as well as at sites where collection Although feeding Big sagebrush was shortest of Feeding Site Shrub Structure 2 groups of samples, I measured but taller than on 0-50 high sites was high relative analysis, (R sites were shorter to canopy cover in other terrain categories. site shrub structure was measured for chemical Big (R - 29%) and similar to was vigorous Big sagebrush were taller and canopy cover in drainages, stands. Canopy cover on > SO northeast 22%) relative among other than 0-50 low. than in all categories 43 and 42, cm respectively) drainage density (f < 0.006, Table 1.4). plants on 0-50 low and> sagebrush of no topographic plants at random sites in drainages (R sagebrush Hypotheses differed between of structure 0.2). Feeding provided site shrub from all sites where shrubs were measured, orientation. shrub structure 1985 and 1986, respectively. at 37 and 50 winter Shrub structure feeding differences the at 9 winter transect orientations (f> of foliage sites in between �56 Table 1.4. Big sagebrush structural characteristics at random and sage grouse winter feeding sites in the Gunnison Basin, Colorado, 1985-86. 0-50 low 0-50 high Random 20 20 Feeding 25 10 Variable N > 50 SW > 50 NE 20 20 20 21 28 3 Drainage sites cmb Canopy, Random Feeding 1,078±55 367±54 959±83 478±66 965±94 1,127±62 1,007±76 < 0.001 Mean height, 636±82 9l5±107 < 0.001 0.11 e cm Random 43.3±2.9 3l. 6±2.l 52.8±1.9 28.8±2.5 41.5±3.5 Feeding 43. 9±l. 7 44.4±3.4 54.l±2.9 41.l±l.6 51.6±3.7 0.86 0.003 of variation Random 29.6±1.5 27.6±2.8 31. 2±1. 6 29.9±2.2 27.8±2.l Feeding 31. O±1. 0 34.5±2.3 31. O±1. 8 32.6±1.1 28.0±3.l 0.56 for height, % O.ll 0.94 0.23 0.71 plants/m2 Random 1. 3±0.1 2.0±0.2 1. 3±0.1 1.4±0.2 1.4±0.l Feeding 1. 8±0. 2 1.4±0 .1 f 1. 2±0.1 1.0±0.1 0.024 0.059 aprobability among terrain bMean canopy 0.001 < 0.001 0.72 Coefficient Density, 0.001 0.049 that mean values of structural variable are similar intercept. Percent categories. total length of big sagebrush cover - mean total length 0.006 = 30. canopy �57 Table 1.4. Cont. CMean ± 1 standard error. dprobability that mean values do not differ between feeding and random sites. eNo comparision northeast (R - site density differed between winters; 1.8±0.2) differed 1986 feeding site density density made in > 50 due to small sample of feeding sites. fFeeding density of feeding and random site structure (E - 0.56). 1985 feeding site from random site density (E - 0.006); (R - 1.3±0.1) was similar to random site �58 winters were evaluated observations drainage, within each terrain category were obtained in both winters > 50 southwest). Sagebrush terrain categories sites was higher exception feeding site shrub structure variation associated category (e.g., drainage Shrub structure data for comparison features, measured differed cm). random sites). to random Sagebrush Within the> height - 29 cm). density (R - 1.8 p1ants/m2) (R at 50 southwest Sagebrush big were canopy cover - 29%, category, R sage canopy cover (R - 33%) and (R - 41 cm) than occurred at random locations canopy cover (R - (R canopy 32%) and (R ~ 44 cm) at feeding sites in the 0-50 high category were also than at random locations Comparison sites. (R canopy cover - 12%, of feeding and random sites in the> terrain was not possible feeding the same terrain In the 0;50 low terrain category, at feeding than at random locations R at from 1985 feeding sites but was canopy cover (R - 36%) and density taller plants of shrub structure (Table 1.4). grouse used sites with greater big sagebrush greater With the with random sites. to random sites within to 1986 feeding sites. density - 1.1 plants/m2). height in drainage I pooled 1985 and 1986 at feeding sites in drainages 'was similar random sites in drainages cover - 16%, density feeding sites vs. drainage sites for 3 of 4 variables greater in drainages, with topographic sites was compared sagebrush Sagebrush (4 showed of Winter Feeding and Random Sites.--Because feeding similar between Only 1 of 16 comparisons in 1985 than in 1986 (f - 0.006). of density estimates Comparison differences structure variables) (f < 0.05) between winters. differences feeding X 4 sagebrush (0-50 low, 0-50 high, structure 1985 and 1986 feeding sites were minimal. for which due to the inadequate sample R height ~ 31 50 northeast (N - 3) of �59 I observed while black sagebrush it was present occurred, between Chemical of black sagebrush Within Among Random Foliage Collection Sites Big sagebrush plants were present 21 plants/site, SE 1.1). (R 20 plants/site, SE 2.6) and was also sampled. This reflected topographic vigor that was also observed differences there were no differences monoterpene was present at 7 sites Big sagebrush in other terrain variation in plant growth and at random sites where shrub structure was differences comprised in site conditions (Table and sagebrush 1.5). plants that grew in different There were also no topographically- (f > 0.05) in the 6 individual monoterpenes 80-90% of the total mono terpene content was no correlation (K - -0.21) or total monoterpene big sagebrush plants sampled at random sites. crude protein content each was found. differences (Table 1.5). There (R content (K = 0.26) in (R - 18.1%) and total monoterpene (R - 1.08%) were lower than protein monoterpene that (f > 0.05) between mean plant height and levels of crude protein Black sagebrush growth forms, (f > 0.05) in crude protein or total content among big sagebrush terrain categories content at each site (Table 1.4). Despite related Black sagebrush in drainages were taller than plants evaluated (f - 0.14) sagebrush plants at 8 r~ndom sites in each of 4 categories. categories. sites where it was similar (R plants feeding sites (R = 7%) and random sites (R = 13%). Variation I collected terrain at 31% of 100 random sites. canopy intercept feeding at only 8% of 87 winter (R 2.15%) of big sagebrush 21.3%) and total at the 7 sites where I did not attempt to evaluate black sagebrush among terrain categories due to small sample sizes. chemical �60 Table 1.5. Chemical characteiistics (% dry matter) of big sagebrush leaves collected at 32 random sites in 4 terrain categories (8 sites/category), Gunnison Basin, Colorado, Harch - April 1986. o - o - 5° 50 low R Category Crude protein Individual SE 19.7 Total monoterpenes high 1.0 2.08 R SE 22.2 1.5 > 50 Drainage R 21.6 SE 1.6 southwest :R 21.5 SE 0.9 0.54 0.2 1.86 0.3 2.23 0.2 2.06 0.1 0.62 monoterpenes Camphene 0.16 0.02 0.15 0.03 0.15 0.01 0.15 0.01 0.98 Artho1e 0.09 0.09 0.10 0.02 0.08 0.01 0.12 0.01 0.23 1,8 Cineole 0.46 0.06 0.40 0.06 0.48 0.03 0.48 0.04 0.62 Camphor 1.03 0.11 0.95 0.12 0.96 0.06 1.01 0.05 0.91 Borneol 0.10 0.02 0.08 0.01 0.10 0.01 0.10 0.01 0.58 28.0 minb 0.05 0.003 0.03 0.007 0.05 0.004 0.05 0.005 0.09 similar among terrains. aprobabi1ity bUnidentified retention time. that means were monoterpene, name designates gas chromatograph �61 Chemical Differences Sagebrush foliage samples were collected sites in 1986. sagebrush (R = Between Browsed and Unbrowsed Big sagebrush was present 15 plants/site, plants/site, SE = dominated = from 20 winter Plants feeding all feeding sites and black at only 1 feeding site. SE Sagebrush A total of 300 browsed 1.0), and 285 unbrowsed (R - 14.3 1.5) big sagebrush plants was collected from feeding sites. Crude protein content was similar 20.6%) and unbrowsed sites (Table 1.6). (£ - 0.80) between sites. monoterpenes Crude protein content of big sagebrush averaged Total monoterpene were also similar big sagebrush plants at at random foliage content and 6 individual (£ > 0.05) between browsed and unbrowsed plants at winter feeding sites (Table 1.6). Monoterpenes 2.0% of dry matter in each group of samples. monoterpene (R = (R - 20.3%) big sagebrush plants at winter feeding feeding sites was similar to values observed collection browsed content at feeding sites was similar Total to values observed at sites (Table 1.5). random foliage collection DISCUSSION Sage Grouse Habitat Use Topographic reflected variation physiographic in shrub structure differences plants were tall and vigorous 50 northeast height was intermediate relative conditions on 0-50 high and> short sagebrush in site conditions. in drainages Soils on 0-50 low and> at random locations Big sagebrush due to mesic conditions. were well drained and sagebrush to other terrain categories. 50 southwest plants with open canopies. sites resulted High sagebrush Xeric in stands of density on �62 Table 1. 6. Chemical characteristics (% dry matter) of leaves of browsed and unbrowsed big sagebrush plants at sage grouse winter feeding sites (N - 20), Gunnison Basin, Colorado, Janaury - March 1986. Browsed Category 2l Crude Protein 20.6 Total monoterpenes Unbrowsed SE 1.1 2l 20.2 SE fa 1.1 0.80 2.00 0.10 2.01 0.12 0.97 Camphene 0.14 0.01 0.15 0.01 0.64 Arthole 0.08 0.009 0.09 0.01 0.71 1,8 Cineole 0.41 0.02 0.41 0.03 0.94 Camphor 1.01 0.06 1.05 0.06 0.68 Borneol 0.10 0.01 0.10 0.01 0.61 28.0 minb 0.04 0.002 0.05 0.003 0.39 Individual monoterpenes aprobability that means were similar between browsed and unbrowsed plants. bUnidentified retention time. mono terpene , name designates gas chromatograph �63 0-50 high sites reflected the tendency of black sagebrush stands of small, closely-spaced plants. Sage grouse foraged at sites where sagebrush was maximized. Topographic distribution was greater than expected shrub growth, mid-winter drainages to snow depth. in both winters. availability of sagebrush than in other terrain categories plants provided were sheltered forage and concealment apparent differences important covers shorter Use of Due to vigorous was greater (Fig. 1.6). in Large sagebrush from avian predators. costs by foraging beneath in drainages especially above snow Drainages from wind and sage grouse may have reduced thermoregulatory structural exposure of sage grouse feeding sites was affected by sagebrush height relative drainages to occur in between random and feeding foraging Drainages may be sites in severe winters when deep snow Schoenberg plants on more arid terrains. that a high proportion winter use sites in Jackson Sagebrush sites were less than in more xeric sites. sagebrush (1982) also observed closed canopies. (32-46%) of sage grouse County, Colorado occurred in drainages even though that terrain comprised < 2% of his study area. A high proportion slopes, although southwest of feeding sites occurred use was not disproportional slopes was shallow relative Shrub structural differences .were apparent between and random sites. canopies more closed at foraging locations shallow small « at southwest snow cover Sagebrush southwest 1 ha) sites beneath Snow on slope plants were taller and shrub than at random sites. slope feeding sites was readily (Fig. 1.6) slopes above drainages. to availability. to other terrain categories. foraging Sagebrush on > 50 southwest Southwest slope foraging rock outcrops available above sites were often or snow cornices, These areas received more moisture and lower than �64 1::::::::::::::1 MEAN SAGEBRUSH HEIGHT AT FEEDING SITES (Z] MEAN SAGEBRUSH HEIGHT AT RANDOM SITES 1<::::::::1 1985 FEBRUARY MEAN SNOW DEPTH ~ 1986 FEBRUARY MEAN SNOW DEPTH 60 50 45 40 ~ o 30 20 10 o DRAINAGE 0_50 LOW 0_50 HIGH >5 o SW Fig. 1. 6. Mean sagebrush height at feeding and random locations relative to snow depth within terrain categories in the Gunnison Colorado, 1985-86. Basin, �65 surrounding sites and sagebrush with slopes> Southwest 12 observations) used in 1986 (15% of feeding sites). of steep southwest following terrain categories Most use (7 of slopes in 1986 occurred slopes became snow-free During the plants and made access to foliage difficult. plants on steep southwest Schladweiler sagebrush of more readily available (1972) observed more quickly of winter use sites on slopes> suggested because 60 in Jackson aspects. January County, Colorado only 13% and exposure Basin regularly slopes foliage readily available at mesic sites where shrub growth was vigorous. was due to differences in 1985 than in 1986. in snow depths between snow depth on 0-50 low sites was shallower than in 1986 (R - 32.9 cm). category rarely used Sage grouse likely f~raged on southwest Use of 0-50 low sites was greater probably Eng and (6-150) to steep (> 150) slopes with snow was shallow and sagebrush localized exploited Beck (1977) observed Sage grouse in the Gunnison areas of moderate southwest than that sage grouse rarely foraged on slopes to minimize to avian predation. occupied forage. that sage grouse in Montana stands on slopes during winter. in most Sagebrush in other areas and sage grouse may have temporarily these sites because during a 3- a severe winter storm in mid-February. storm, wet snow became lodged in crowns of sagebrush plants aspects 150 were rarely used in 1985 (1% of feeding sites) but were more heavily day period growth was vigorous. in 1985 occurred accumulations. This years. Mean in 1985 (R Many (48%) observations in January prior to heavier = 17.5 cm) in the 0-50 low mid-winter snow Use of 0-50 low sites was reduced when snow depths exceeded approximately winter. Sagebrush 30 em in February 1985 and throughout stands on 0-50 low sites consisted shorter plants than stands in drainages. the 1986 of slightly Snow was deeper than on �66 southwest of deep snow (> 30 em) foraging slopes. During periods were less available proportion on 0-50 low sites because of the sagebrush structure snow covered than in drainages Canopy cover and density were greater at winter to random feeding locations. However, and random locations. periods Uniform (Fig. 1.6). feeding sites relative soils and topography in sagebrush stands of tall sagebrush approximately of 0-50 low growth characteristics. that could be exploited of deep snow were not widely available snow depth exceeded a higher sagebrush height did not differ between sites did not promote heterogeneity Localized sites during on 0-50 low sites. When 30 cm, sage grouse were less likely to forage on 0-50 low sites and more likely to exploit other terrain categories reported where sagebrush was more available. greater winter use of flat « 50) Schladweiler 1972, Beck 1977). However, were shallow (3-25 cm) relative to Other researchers areas by sage grouse have (Eng and snow depths in those studies winter conditions in the Gunnison Basin during 1985 and 1986. Only 13% of feeding sites were observed ~ Average height canopies greater of big sagebrush than on southwest interspersed of its short height, by shallow aspects as winter habitat. were exposed on 0-50 high sites. completely Because even snow to wind may have made 0-50 high sites less Feeding sites on the 0-50 high category Because mesa and ridgetops snow tended to become drifted and vigorous was covered Small plant size, moderate in shallow depressions. to winds, and Snow depths were Black sagebrush black sagebrush was usually snow depths of 20-30 cm. occurred depressions (Fig. 1.6). with big sagebrush and greater exposure favorable usually plants at these sites was shorter were more open than in more mesic terrains. frequently depths, on 0-50 high sites. ;. sagebrush in shallow growth was favored. �67 I observed only 3 feeding sites on slopes with northeast even though that terrain category comprised of the Gunnison Basin. a large percentage Snow was deeper on northeast other terrain categories. aspects, Also, big sagebrush (30-32%) slopes than in most plants were smaller and canopies more open than in drainages. northeast slopes was covered as a result of deep snows (Fig. 1.6) and foraging sites were not available. Most sagebrush Northeast foliage on slopes may be used during mild winters with little snow. However, in normal winters when snow depths are> 30 cm on northeast slopes, little foraging is likely to occur in that terrain category. Sage Grouse Forage Selection Sage grouse foraged at sites where big sagebrush was the dominant shrub species. 8% of winter Black sagebrush was rarely consumed feeding sites. grouse in Idaho usually sagebrush resource was usually Dalke et a1. (1963) observed foraged on black sagebrush. snow covered and not readily in the Gunnison Basin. Black sagebrush ridges and mesas at sites where sagebrush to winds. Taxonomic concentrations subspecies Tisdale on subspecies concentrations in foliage protein has been observed 1979, 1981). is influenced 1977). that sage However, available primarily black as a forage occurred on fed on big sagebrush due content. variation (Welch and McArthur at only plants were short and exposed Sage grouse may have preferentially to its higher protein and occurred and monoterpene among subspecies Distribution by site conditions of big sagebrush and topography Sage grouse have been observed and Braun 1985). (Winward and to preferentially of big sagebrush with high protein (Remington of big sagebrush forage and low mono terpene Topographic distribution of �68 feeding activity physiographic distribution 1965, Remington subspecies Foliage in some sage grouse populations and Braun 1985). of big sagebrush crude protein big sagebrush distribution influenced plants in different variation Remington Selection big sagebrush Similarities plants in crude protein composition of 18 individual a site. 24% crude protein) of sagebrush sage grouse concentrations. (Hoffmann 1961. in the Gunnison concentrations composition were variable The magnitude These results was not necessarily and unbrowsed of sagebrush analysis plants collected and unbrowsed Basin. of browsed plants was for selection I evaluated did protein from 3 feeding sites. among plants that grew of variation within was similar to the total variation data). content 1970, Doerr et al. 1974, Hohf et al. in a preliminary concentrations within Hupp, unpubl. feeding sites feeding sites, and that opportunities However, together that within of big sagebrush, that chemical not exist. Crude protein Basin was primarily foliage chemistry. plants were not apparent within Physiographic in crude protein content of browsed could indicate uniform were similar among in other grouse species et al. 1970, Pulliainen Differences Basin. plants or plant parts with high protein observed (Gill foliage above snow and not by fed on plants with high crude protein has also been widely 1987). in the Gunnison in the Gunnison and Braun (1985) observed of individual subspecies terrain categories. in sagebrush the big sagebrush was the only concentrations of sagebrush of a single subspecies selectively Miller that occurred and monoterpene by availability big sagebrush Mountain of sage grouse foraging topographic comprised of preferred may reflect indicate among sites (J. W. that chemical uniform within sites (14- composition feeding sites and that �69 opportunities for sage grouse to selectively forage on higher protein plants within sites did exist. Protein levels of both browsed 20.2%) mountain relative big sagebrush to protein (R - 20.6%) and unbrowsed plants in the Gunnison concentrations in Wyoming (R - Basin were high 14.1%) and mountain (R ~ 10.8%) big sagebrush plants in northern Colorado Braun 1985). species Crude protein Miller relative nitrogen Herbivores lagopus scoticus), forage resources rich sites populations rich protein that forage in were greatest In the Gunnison leaves was higher exploited (Lagopus content between browsed at nitrogen-poor for high protein plants was weaker (Moss 1972, Lance 1983). forage resources that are low in In' red grouse in protein (Ca1luna vulgaris) of big sagebrush 1961, plants or plant parts than herbivores (Mattson 1980). the differences sites while selection (Hoffmann 1970, Moss 1972, Doerr et a1. 1974, Hohf concentrations heather and are also low (6-14% of Basin big sagebrush that exploit rich environments and unbrowsed content selection may be more likely to select individual with higher protein nitrogen protein to Gunnison et al. 1970, Pul1iainen et a1. 1987). (Remington levels of forages used by other grouse that have demonstrated dry matter) (R ~ than at nitrogen- Basin, protein protein levels of by other grouse species or sage grouse thus far studied. Gunnison Basin sage grouse exploited a forage and birds may have been less likely to selectively forage on higher protein plants within sites. Remington and Braun (1985) observed foraged on subspecies monoterpenes, of big sagebrush with low concentrat~ons and that within stands of mountain grouse selected Monoterpenes that sage grouse selectively big sagebrush, plants that were low in oxygenated have been observed of sage monoterpenes. to depress bacterial digestion in �70 ruminants (Nagy et al. 1964, Oh et al. 1968, Schwartz Remington and Braun monoterpenes could influence forage selection terpenes (1985) suggested bacteriostatic minimized has been observed al. 1980b, Farentinos Although avoidance vertebrates, browsed of monoterpenes Basin. Avoidance monoterpenes Individual (Schwartz et among herbivorous did not differ between plants at sage grouse feeding sites plant selection on the basis of content may be less likely to occur when concentrations monoterpenes are low. Remington and Braun for low mono terpene plants within sagebrush (mean mono terpene content - 1.4%) but did observe 2.6%). low stands of mountain Monoterpene (R - big sagebrush concentrations 2.0%) in the Gunnison study area. Although cautiously due to dissimilar equipment, monoterpene sagebrush stands of Wyoming big of mountain between big sagebrush to Remington studies gas chromatography concentrations effects procedures within Gunnison of monoterpenes known and need to be experimentally of sage grouse forage selection plants were and Braun's should be interpreted and Basin big may have been below levels at which selection The biological selection (mean mono terpene content - Basin relative differences of (1985) did not observe selection within of et al. 1987). has been observed big sagebrush of and that sage grouse in other species of herbivores total and individual in the Gunnison effects mono terpene consumption. et al. 1981, Personius and unbrowsed monoterpene avian cecal digestion et a1. 1980a). would occur. on sage grouse digestion determined before are not' the significance can be fully evaluated. �71 MANAGEMENT IMPLICATIONS Winter foraging activity not evenly distributed distribution topographic among physiographic variation in big sagebrush Instead, Physiographic exploited Sagebrush because vigorous cover availability. crude protein by or monoterpene sage grouse foraged at sites where sagebrush above snow was maximized. frequently features. Basin was of sage grouse feeding activity was not influenced concentrations. exposure of sage grouse in the Gunnison Southwest in drainages shrub growth insured forage and slopes were also frequently snow depth was shallow and sagebrush was foliage was available sites. Use of 0-50 low sites was variable depth. Less foraging and dependent used because at feeding upon snow occured on 0-50 low sites during periods of deep (> 30 cm) snow because sagebrush foliage was less available. Mesa and ridge tops were not heavily plants on exploited because these xeric sites were often covered by snow. foraged on northeast short sagebrush Sage grouse rarely slopes even though sagebrush plants on northeast slopes were taller and canopies more closed than stands in more xeric terrains. Deep snows typically limited shrub exposure on northeast slopes. Structural value measures in assessment Sagebrush structure of big sagebrush would be of relatively of sage grouse winter habitat relative would need to be considered for each topographic to distinguish drainages. depth. to topographic and separate category. random locations variation structural Structural variables Basin. in snow depth criteria established were not adequate from sage grouse feeding Use of 0-50 low sites was variable It would not be feasible in the Gunnison little sites in and dependent upon snow to define a range of structural �72 characteristics 50 low feeding measures that could be used to consistently sites among winters are potentially availability availability conditions whether severity. useful to identify winter on southwest is questionable of differing identify potential is necessary Structural feeding site slopes, and mesa and ridge tops. identification of winter on these terrains. of these sites, sagebrush 0- However, it feeding site Due to the xeric removal to improve grass forage is not likely to occur. Physiographic and distribution Basin. criteria of sage grouse winter Maintenance important appear to be useful to assess availability of sagebrush in drainages in drainages 10% of the sagebrush Higher percentages exposed vegetation and was available sagebrush During'the in the Gunnison to sage grouse (J. occurred 1985-86 winter~. in drainages. W. Hupp, unpubl. Drainages that was exposed are a small (3-4%) of the total land area in the Gunnison frequently the focus of sagebrush growth. Removal of sagebrush disproportionally severe effect on availability feeding habitat. Maintenance also be emphasized on that terrain. occupied due to the frequent has a of sage grouse winter on southwest observation These findings have implications by sage grouse in which terrain Basin, yet are due to the vigorous in drainages of sagebrush data). in the region were proportion sagebrush is available Basin was not snow- Sagebrush treatments Maintenance severe 1984 winter < (78-84%) of sagebrush vegetation during the milder in 1984 primarily in this area. assures that vigorous to sage grouse during severe winters. in the Gunnison is a particularly aspect of winter habitat management of sagebrush covered feeding habitat slopes should of foraging activity for other regions is heterogeneous, winter snows �73 typically exceed 30 cm on low flat areas, and where mountain sagebrush is the dominant shrub species. LITERATURE CITED Alldredge, J. R., and J. T. Ratti. statistical techniques Wildl. Manage. Autenrieth, Burnham, 1986. Comparison for analysis of resource from line transect Wildl. Monogr. Beck, T. D. I. 72. 1977. selection sampling availability J. Wildl. Manage. data. J. W. 1977. Estimation An ecological Ph.D. Thesis, Washington Practical and habitat Wild1. for Soc. Bull. 5:99-106. 1984. of utilization- 48:1050-1053. study of sage grouse in State Univ., Pullman. nonparametric statistics. 84pp. John Wiley and Sons, New York, N.Y. 49lpp. Dalke, P. D., D. B. Pyrah, D. C. Stanton, J. E. CrawforQ, Schlatterer. of populations. Guidelines for analysis J. Wildl. Manage. 1982. 1980. 42pp. 41:18-26. and P. R. Krausman. of a technique J. W., Jr. 1980. Sage grouse flock characteristics Byers, C. R., R. K. Steinhorst, Conover, Sage grouse management of biological of sage grouse habitats. Clarification J. 202pp. in winter. maintenance Idaho. 1982. and J. L. Laake. Braun, C. E., T. Britt, R. O. Wallestad. Connelly, selection. West. States Sage Grouse CQmm. Tech Bull. 1. K. P., D. R. Anderson, density of some 50:157-165 R., C. Braun, and W. Molini. practices. big 1963. sage grouse in Idaho. Ecology, productivity, and E. F. and management J. Wildl. Manage. 27:811-841. of �74 Doerr, P. H., L. B. Keith, D. H. Rusch, C. A. Fischer. Characteristics in Alberta. of winter feeding aggregations J. Wi1dl. Manage. Eng, R. L., and P. Sch1adweiler. and habitat 1974. of ruffed grouse 38:601-615. 1972. Sage grouse winter movements use in central Montana. J. Wildl. Manage. 36:141- 146. Epstein, W. M., L. R. McGee, C. D. Poulter, Mass spectral and L. L. Marsh. data for gas chromatograph identification 1976. - mass spectral of some irregular monoterpenes. J. Chern and Eng. Data 21:500-502. Farentinos, R. C., P. J. Capretta, 1981. Selective monoterpenes herbivory in ponderosa R. E. Kepner, in tassel-eared and V. M. Littlefield. squirrels: role of pines chosen as feeding trees. Science 213:1273-1275. Gill, R. B. 1965. Distribution and abundance grouse in North Park, Colorado. Univ., Heller, Fort Collins. data base. Higby, L. W. 1969. project. M. S. Thesis, Colorado sage State 187pp. S. R., and G. W. A. Milne. spectral of a population Editors. 1978. EPA/ErH mass U. S. Dep. Corom., Washington, D.C. 988pp. A summary of the Longs Creek sagebrush control Proc. Bien. West. States Sage Grouse Workshop 6:164- 168. Hoffmann, R. S. 1961. Wi1d1. Manage. Hohf, R. S., analysis Manage. The quality of winter food of blue grouse. 25:209-210. J. T. Ratti, and R. Croteau. of winter 51:159-167. 1987. Experim~nta1 food selection by spruce grouse. J. Wi1d1. J. �75 Horwitz, W. Editor. Anal. Hunter, Chern. A. N. D.C. Mattson, Miller, D.C. W. J., Jr. 1980. Pages populations 323-335 to their R. Ecol. Herbivory in A. Watson, (Lath.) Wildl. Brit. in relation 1970. in relation to plant 14:78-80. nitrogen Responses improvements Animal Ecol. Scand. 11:119-161. populations in relation 10. (Lagopus to chemical of red of their food. Soc. Symp. by red grouse Manage. Oceanic lagopus composition. J. Anim. Admin. 91:4-6. R. L. Denver, Administration. Nat1. and W. M. Longhurst. inhibition from relatively Microbio1. Effects on deer rumen microbial U. S. Dep. Comm., Oh, H. K., M. B. Jones, microbial 1964. of function. J. 28:785-790. and Atmospheric Colorado. isolated and G. M. Ward. oils of sagebrush data, Patterson, ed. Ornis 41:411-428. essential rumen Serv., sites by hen red grouse to experimental J. E., H. W. Steinhoff, National Off. of the Gunnison Soil Conserv. and D. Jenkins. Food selection scoticus) Soil survey during breeding. food resources. 1972. 1975. Rev. Eco1. and Syst. G. R., A. Watson, grouse Assoc. l018pp. of feeding scoticus Annu. of analysis. 89pp. Selection lagopus content. methods U. S. Dep. Agric., 1983. Lagopus Nagy, Washington, Colorado. Washington, Moss, Official W. R., and C. F. Spears. area, Lance, 1980. resulting unplalatable 1986. Oceanic 1968. and Atmospheric Comparison from various plant Climatological of essential oils species .. Appl. 16:39-44. 1952. Colo. The sage grouse 341pp. in Wyoming. Sage Books, Inc. �76 Personius, J. R. Stephens, and R. C. Kelsey. T. L., C. L. Wambolt, 1987. Crude terpenoid sagebrush. Pulliainen, E. influence on mule deer preference J. Range. Manage. 1970. capercaillie Composition for 40:84-88. and selection (Tetrao urogallus) of winter food by the in northeastern Finnish Lapland. Suomen Riista 22:67-73. Remington, T. E., and C. E. Braun. in winter, Schneegas, 1985. North Park, Colorado. E. R. 1967. Sage grouse food selection J. Wildl. Manage. 49:1055-1061. Sage grouse and sagebrush North Am. Wi1d1. and Nat. Resour. Conf. Schoenberg, T. J. 1982. Collins. Schwartz, and habitat M.S. Thesis, Colorado selection State Univ., Fort 86pp. C. C., J. G. Nagy, and W. L. Regeliri. yield, terpenoid deer. J. Wildl. Manage. concentration, _________ , W. L. Regelin juniper Trans. 32:270-274. Sage grouse movements in North Park, Colorado. control. 1980a. and antimicrobial Juniper oil effects on 44:107-113. , and J. G. Nagy. forage and volatile 1980b. Deer preference oil treated foods. J. Wildl. Manage. 44:114-120. Scott, T. G., and C. H. Wasser. plants for wildlife biologists. Washington, Wallestad, 1980. R. O. treatment. D.C. Checklist of North American The Wildlife Society, Inc., 58pp. 1975. Male sage grouse responses J. Wildl. Manage. ________ , J. G. Peterson, grouse in central Montana. to sagebrush 39:482-484. and R. L. Eng. 1975. Foods of adult sage J. Wildl. Manage. for 39:628-630. �77 Welch, B. L., and E. D. McArthur. crude protein uniform among Artemisia garden. 1981. subspecies in a uniform Winward, Variation complex Stn. Bull. 19. in Idaho. lSpp. subspecies of monoterpenoid of Artemisia J. Range Manage. A. H., and E. W. Tisdale. in winter levels grown of in a 32:467-469. and accessions garden. tridentata Variation tridentata J. Range Manage. _______ , and sagebrush 1979. 1977. content among tridentata grown 34:380-384. Taxonomy of the Artemisia Idaho For., Wildl., and Range Exp. �78 CHAPTER 2 ENDOGENOUS RESERVES AND COURTSHIP BEHAVIOR OF ADULT MALE SAGE GROUSE INTRODUCTION The energetic and nutritional many avian species. energetic (Korschgen mobilization defense demands associated 1977. Drobney of endogenous reserves has also been observed 1981; Brittas Hohman Females may use endogenous and nutritional incubation 1984; Alisauskas 1986). endogenous 1986). Female reserve Whether reserves to meet with follicle 1980. Ankney 1984). during courtship and Ankney reproductive growth and Male or territory 1979; Krapu 1985; Krapu et a1. 1985; success may be influenced size (Ankney and MacInnes by availability are high in (Ankney 1977. 1984; Raveling male reproductive also be mediated costs of r~production by 1978. Krapu 1981. Erikstad success or courtship of endogenous behavior reserves may is poorly understood. Species insights courtship displays of Tetraoninae regarding behavior. the relationships and reproductive and prolonged 1970) likely result use endogenous Opportunities that display periods to examine between to partially relationships male endogenous success. of courtship in high energetic reserves on leks may provide Elaborate among males: meet energetic between reserves. courtship in 1ek species demands useful (Hjorth Males may costs of courtship. endogenous reserves and �79 courtship exist in lek species because courtship be quantified Previous during concurrent studies of breeding Tetraoninae evaluation behavior of endogenous season endogenous reserves. reserves among male that display on leks have not been reported. the extent to which male energetic of males can Therefore, reserves are used during courtship is unknown I examined breeding season fat and protein sage grouse in 2 Colorado populations. reserves of adult male The study was divided into 2 phases. In the first phase, I tested the hypothesis mobilize lipid and protein reserves during the period on leks. I also compared differences years to evaluate deposition. that they display reserves among the effects of winter severity on lipid and protein In the second phase of the study I compared lipid reserves differences in endogenous that males and courtship behavior between populations in display behavior display occurred and determine whether in a population adult male to examine faster rates of with larger lipid reserves. METHODS Phase 1: Male Endogenous Reserves During Spring Courtship Adult male sage grouse were collected Gunnison counties, Colorado (Fig. 2.1). on leks in Jackson The study areas were (> 200 km) from each other. geographically separated high elevation (> 2000 m), sagebrush-dominated and Braun (1985). Both areas are intermontane Study areas have been described by Hunter and Spears (1977), and Remington and basins. (1975), Beck Males were collected in Jackson County during 2 discrete sampling periods courtship) from 1983 through 1985. In Gunnison annually (early and late County, collections �80 COLORADO JACKSON CO . • DENVER GRAND JUNCTION • ~GUNNISON co. Fig. 2.1. Colorado study areas. �81 during early and late courtship were obtained in 1984 and 1985. The early sampling period occurred during the first 2 weeks that males consistently displayed Early collections occurred prior to or during Severe winter weather populations; on leks and was usually between week of April. peak female attendance. in 1984 delayed courtship early courtship collection The late courtship 22 May in each year. collected 14 and during night-time Usually no more than 2- from a single lek within a sampling period. 8 and 10 adult males were collected during all years in both populations. in each sampling period Endogenous reserves of 96 adult male sage grouse were evaluated between Following in both sampling period was between trapping on or near leks (Giesen et al. 1982). Between initiation did not occur until the final Males were primarily 3 males were collected 1 and 15 April. collection, frozen in plastic bags. 1983 and 1985. (± 5 g) then sealed and males were weighed Prior to laboratory from a total analysis, carcasses were thawed and culmen, tarsus, and wing length from the carpals to the tip of the longest primary measured. distally from the carpals were removed and discarded. (~. pectoralis and~. excised and weighed. tibiotarsus) supracoracoideus) Leg muscles gizzard, intestines, Breast muscles on I side of the body were (all muscles attached were excised and weighed also removed and weighed. Muscles Feathers, head, tarsi, and wings in 1985. Gut contents to the femur or Internal organs were (ingesta in the esophagus, and caeca) were removed, weighed, and discarded. and internal organs were returned to the carcass. was refrozen homogenate then homogenized meat grinder. The was spread on aluminum foil and dried in a forced air oven at 80 C for 24 hours. carcasses 4-6x in a commercial The carcass Kerr et al. (1982) found that drying of Microtus at 120 C did not affect lipid reserves. The dried carcass �82 was further homogenized in a high speed Wiley Mill until it passed through Lipids were extracted a screen. 2-rnrn homogenate of with diethyl ether for 6 hours in a Soxhlet apparatus. Dobush et al. (1985) observed for carcass Repeated from lO-g subsamples analysis because extraction that diethyl ether was a suitable it did not extract of some samples for an additional remove more lipids from the homogenate. considered adequate for exhaustive structural Six hours was therefore extraction of lipids from sage Dobush et al. (1985) also observed ether exhaustively extracted determined carcasses lipids from homogenized within 6 hours. from subtraction lipids. 6 hours failed to grouse carcasses. caerulescens) solvent that diethyl snow goose (Chen Weight of lipids was of post-extraction mass from pre-extraction mass. Hypotheses lipid reserves, of no differences in live weights, or breast muscle weights periods were tested using 2-way analysis tarsus lengths, among years or courtship of variance for each population. Live weight was body weight at collection of ingesta. Lipid reserves were expressed Breast muscle weight supracoracoideus as percent (the combined weights of the reserves. In sage grouse, likely the major source of labile protein. mass would be indicative Phase 2: Endogenous I compared between Reserves the breast muscles Changes and Courtship are in breast muscle Behavior and courtship in 1986 to test the hypotheses rates differed between by 2) was used as of protein mobilization. adult male lipid reserves populations of live weight. tl. pectoralis and tl. from 1 side of the body multiplied an index to protein minus the weight populations behavior that male display and that male lipid reserves were �83 larger in a population collected with more rapid display. in each population during early courtship and lipid reserves were evaluated each population accessible for evaluation by vehicle as in Phase 1. behavior was observed between 9 April and 6 May. Evaluations in each population at leks. temperatures ranged between Evaluation adequate Numbers minutes nuptial behavior 1970) and strutting investment were made of 150-200 m. (about 0.75 hours before 20-minute for observation from yearlings plumage. intervals. of courtship Adult behavior. by their large size and Selected males were observed displays The strutting for 5 (Wiley 1973) observed display during is the predominant of male sage grouse on leks (Lumsden 1968, Hjorth rates were presumed in courtship. to be indicative Time that males were involved (chases, fighting, the 5 minutes 1.75-2.0 hours prior to Observations at approximately selected that period recorded. disputes arrived display began as soon as light was and number of strutting courtship when low of females and adult males on leks were recorded. Adults were distinguished distinctive were -8 and 2 C, winds were < 16 krnfhour, and males from females Lek counts were repeated males were randomly on each lek were during mornings Observers of courtship (17-27) of of display behavior scope from a distance to distinguish sunrise). Leks were during 5 mornings to record time of first display. through a spotting 3 leks in during the period of peak female All observations there was no precipitation. sunrise I selected and were attended by similar numbers Courtship attendance (1-15 Apr) in 1986 of courtship ?ehavior. males. initiated Ten adult males were of observation confronted displays was recorded. of energetic in territorial [Hjorth 1970]) during I also recorded time birds �84 spent in crouched positions and common ravens (Cor,~s corax). Female-male rates distance influences (Gibson and Bradbury male and the nearest 1985). Distance males continued maximum number Evaluation Number of males observed rates were corrected disputes or avian predator female distance (Norusis survey period. was calculated disturbance. between populations for each male. due to territorial Males, for which disruption that mean strutting categories of display rates Hotellings display did not differ between populations statistical Differences between 12 was used populations. procedure simultaneously for each lek- rates across lek- that tests across several variables in lipid reserves were evaluated with ~ tests. of faster display rates in a population male lipid reserves behavior selected the lek was recorded. category within a population. 1986:117). relationship period was on leks to facilitate for time of disruption 12 is a multivariate Observation selected 20 cm high) Mean display rates were calculated to test the hypothesis female distance « Small 2 minutes were not used for comparison populations. differences observation during the morning displays/minute Display Hotellings a randomly until the number of males on leks was < 25% of the of strutting time exceeded display of display rates of randomly Time at which 75% of males had abandoned between between female during the 5-minute estimation. avian predators sage grouse strutting stakes were placed at 10-m intervals distance between to potential as either < 10 m, 10-30 m, or > 30 m. recorded wooden in response would not necessarily indicate size of male energetic but would provide supportive a cause and effect reserves evidence with larger and courtship for the hypothesis that �85 courtship is affected by endogenous dissimilar display reserve size. Observ~tion of display rates when lipid reserves were equal, similar rates when reserves were unequal, population with larger energetic interpopulation relationship or slower display reserves would between indicate lipid reserve rates in a that an size am± courtship J behavior was not likely. RESULTS Phase I: Male Endogenous Reserves During Spring Courtship live weights "dLf'f er-ed Body Mass and Size. -- In each population, (r < 0.05) among years but not between courtship periods (~ble 2.1). Males collected in other years between in 1984 were lighter than individuals (Table 2.2). courtship Differences populations. from Jackson Gunnison periods County. 2.2). Couty weighed each population, among years and between among years. lipid reserves reserves early and late courtship Lipid reserves (Table 2.2). similar among years (Table 2.2). in all years (Table that indtcated reserves were not similar during early courtship than in other years of male during early there were also strong interactions between in early and lateccourtship In both study areas, lipid reserves However, 10%~shorter (Table 2.2). were larger than late courtship differences 25-30% less ethan males Tarsus lengths were approximately Reserves.--In sage grouse differed courtship in each population. in adult male body size were apparent between County males (Table 2.1). Tarsus lengths were similar among years and Males from Gunnison Endogenous co11etted Late courtship were lower in 1984 lipid rese~es were �86 Table 2.1. Differences in sage grouse physical characteristics among years and between courtship periods (2-way ANOVA) , Gunnison and Jackson counties, Colorado, 1983-85. ,_- ," County -- Year Variable Courtshin fa E neriod fb E Year x neriod fC E Jackson Lipidsd 24.4 < 0.001 2~8.l Live weighte 16.1 < 0.001 0.3 0.59 1.2 0.31 < 0.001 < 0.001 24.5 Breast musclef 3.0 0.06 0.7 0.42 3.1 0.05 Tarsus 1.6 0.21 1.7 0.20 3.1 0.06 8.5 0.006 Gunnison Lipids 14.5 0.001 < 0.001 70.7 "Live weight 5.8 0.02 2.8 0.10 1.0 0.76 Breast muscle 2.5 0.13 2.8 0.11 0.2 0.67 Tarsus 1.7 0.21 0.008 0.93 1.8 0.19 - _-s.. ...:... -"-- aprobability that means are similar among years. bprobability that means are similar between early and late courtship. cProbability that differences between early and late courtship means are similar among years. dLipids as percent of live weight - weight of digestive tract contents. eBody weight at time of collection - weight of digestive tract contents. fCombined weights of tl. nectoralis and tl. sunracoracoideus. �87 Table 2.2. Physical characteristics of adult male sage grouse during courtship in Gunnison and Jackson counties, Colorado, 1983-85. County Year Period Live weight {g)a SE H :R Li12ids {%)Q SE :R Li12ids {g) SE :R Breast muscle {g)£. Tarsus{mm) SE SE :R :R Jackson 1983 Early 9 2,863 32 5.4 0.38 155 10.8 654 8.4 74.1 0.58 10 2,799 45 1.1 0.20 30 5.3 612 13.2 72.6 0.85 Early 10 2,524 61 2.3 0.38 59 10.6 597 14.7 74.7 0.56 Late 10 2,598 41 0.8 0.10 20 3.1 614 11.4 72.9 0.94 Early 10 2,651 57 5.5 0.29 145 7.6 608 13.4 74.0 0.53 Late 10 2,699 37 0.5 0.10 13 2.3 607 10.8 75.1 0.45 10 1,897 20 2.2 0.44 42 8.2 437 11. 7 69.9 0.47 9 1,846 57 0.7 0.10 12 1.8 423 7.7 69.2 0.21 10 1,996 37 4.1 0.25 82 5.6 458 12.6 68.6 0.69 8 1,923 21 0.8 0.10 16 1.9 435 8.7 69.3 0.52 of digestive tract Late 1984 1985 Gunnison 1984 Early Late 1985 Early Late aBody weight at time of collection - weight contents. bLipids as percent of live weight - weight of digestive tract contents. cCombined weights of M. 12ectora1is and M. supracorecoideus. �88 In Jackson County, breast muscle mass differed years but did not vary between (Table 2.2). grouse in Gunnison periods. 1983 was high relative to Breast muscle mass of adult male sage County did not differ between Among Jackson among (Table 2.1). early and late courtship Breast muscle mass during early courtship other periods slightly years or courtship County males, leg muscle mass (~ - 123 g, SE 2.8) during early courtship was similar-(f - 0.14) to muscle mass during late courtship (f - 0.94) between differences (~ = early (~ - 102 g, SE - 3.0) and late County. Early courtship 1984. There were also no (~ -102 g, SE - 2.0) leg muscle mass among males from courtship Gunnison 130 g, SE - 3.3). (~- However lipid reserves were similar between populations in 1985, lipid reserves of Gunnison in County sage grouse 4.1%) were low (f < 0.01) relative to Jackson County males (~ - 5.5%). Phase II: Endogenous Reserves Male Display Rates.--A observations) grouse display and Courtship total of 23.6 hours was spent measuring in Gunnison and Jackson f - 0.023). Rates of strutting County males (Fig. 2.2). differences counties. with greater male-female well as among males> Other behavioral Leks in each population Differences populations in strutting (Hotellings r2 - 64.2, display were slower among Gunnison Strutting were most apparent (284 5 minute display rates of adult male sage rates were apparent between diminished Behavior rates in both populations distance. Interpopulation among males within 10 m of females as 30 m from females. differences were apparent between were visited populations. during evening hours approximately �89 G6.2.0.4 - JACKSON 6 GUNNISON 1J.J I- :::l G Z :E .... 5.2±0.1 <, en >- . ...•. ....•.... ......•. ...... "''G , ,, 4 -c .....J 4.2:t 0.2 a... " ,, ,.•. en 25 ,.•. ,.•. 2 .•. , .•. .•. ,, , '8 < 10 2.1±0.2 1.3±0.3 10- 30 DISTANCE TO FEMALE (m) Fig. 2.2. Strutting display rates (K ± S.E.) of adult male sage grouse in Gunnison and Jackson counties, Colorado, April-May 1986. �90 1-2 weeks after the peak of female attendance. not evaluated during evening periods although numbers males were recorded. displaying Male sage grouse in Jackson on each of 7 occasions when evening on S leks. Numbers were similar of males observed to numbers males were observed recorded leks where between grouse in Jackson courtship evaluation (12-4S) In Gunnison County, during morning. sagebrush Male sage County were rarely trapping. Males in Gunnison cover adjacent of strutting displays, to leks. sage grouse in Gunnison in adult male attendance However, populations (E - Gunnison than in the Jackson in Gunnison Variance in daily (Table differed between Peak numbers of adult male sage County leks were more variable County population Lipid Reserves.--Early did not differ between populations In 1986, early courtship weight in male attendance 9.43, f < 0.01). 1986 Early Courtship reserves during morning was similar among leks within populations variance grouse that attended mornings patterns were also apparent between populations. peak male attendance 2.3). 1.0-1.S sunrise. Differences courtship County Preceding County were heard flying to and landing on leks approximately hours before on roosted on leks at night during the males in Gunnison on leks during night-time morning courtship was recorded In each instance only 2 males were displaying However, in vigorous County were observed observed during morning. County typically roosted of displaying during evening display 36 and Sl males displayed season. rates were on only 2 of 9 occasions when evening displays were on S leks. observed Strutting among (Table 2.3). courtship in 1986 lipid (f - 0.27). lipid reserves were 4.1% (SE - 0.3) of live County male sage grouse. Early courtship lipid �91 Table 2.3. Peak daily attendance of adult male sage grouse at 3 leks in Gunnison and Jackson counties, Colorado. Surveys were conducted during 5 mornings on each lek, April-May 1986. County .§.2b Lek Range Jackson Railroad 27.0 0.5 26-28 Ridge Road 17.0 2.0 15-19 Deer Creek 19.6 4.3 16-21 ~.£c - 2.27 Gunnison Ohio Creek 17.8 20.7 11-23 Chance Gulch 20.6 29.8 12-26 South Parlin 19.8 13.7 14-24 ~.f. - 21.4 aMean daily peak attendance of adult males. bVariance in daily attendance of adult males on individual cVariance in daily attendance of adult males pooled across leks within a population. leks. �92 reserves were 3.6% (SE - 0.3) of live weight for adult male sage grouse collected in Jackson County. DISCUSSION Sage Grouse Body Mass Sage grouse body weights courtship within populations. observed that live weights courtship. probably The disparity attributable did not differ between Beck and Braun between their findings to differences in sage grouse body weights large samples (1978) previously of adult male sage grouse diminish results were based on a large sample within early and late and my results are in sample sizes. Beck and Braun's (N - 465) of adult males. during courtship due to variance during Changes may only be apparent within collection periods (Table 2.2). Lipid Deposition and Winter Severity Male sage grouse lipid reserves 1983). Reserve winter severity. size at the begining Early courtship County were highest reduced males in Gunnison winter. March following following increase during winter of courtship lipid reserves mild winters severe winter conditions (> 50 cm) persisted among males in Jackson in 1984. Lipid reserves the severe 1984 from December 1984 in each study area and temperatures averages is affected by in 1983 and 1985 but were County were also low following Deep snows (Remington 1983 through were below 30-year (Table 2.4). Reduced winter result of conditions due to increased endogenous reserves in avian species can be the that limit access to forage resources thermoregulation demands resulting or may be from low ambient of �93 Table 2.4. Winter (Nov-Mar) snowfall and mean temperature departure from 30-year averages in Gunnison and Jackson counties, Colorado, 19831986. Lipid reserves of adult male sage grouse during early courtship. Jackson 1984 1985 1983 Snowfall, cma Temperature departure, Lipids, %c Jackson 1986 l66b 186 97 90 1.2 -0.7 0.2 1~9 -3.1 1.7 2.3 5.4 2.3 5.5 3.6 2.2 4.1 4.2 Climatological bSnowfall Gunnison 1985 102 aData are from National Monthly 1984 163 124 C 1986 Oceanic and Atmospheric Data for Colorado, accumulations Administration 1983-86. in December 1985 are not available for County. cLipid reserves digestive expressed as percent of live weight - weight of tract contents. temperatures (Dugan et al. 1981, Mortensen 1984, Heitmeyer lipid reserves 1985). et a1. 1983, Whyte and Bolan Both factors likely contributed in male sage grouse in 1984. the sagebrush vegetation to reduced In Gunnison County, was covered by snow in 1984 (J. W. Hupp, unpub1. data) while in 1985 and 1986 only 16-22% of the sagebrush habitat was snow covered. both populations Access to sagebrush and in Jackson forced to forage on nutritionally (Remington and Braun 1985). costs during feeding. severe winters inferior subspecies Deep snows increase Distances forage was reduced in County, sage grouse may have been between of big sagebrush sage grouse locomotion exposed plants increased and, based on track observations sage grouse usually 93% of in Gunnison in County, sank 5-10 cm into soft snow while foraging. Low �94 temperatures reduced also increase thermoregulatory lipid deposition. Severe winter weather breast muscle and live weights Early courtship not initiate reduced display activities until late April. (R- 2,764 early April males captured gm). was delayed reserves Live weights in reduced in 1984 because males did It is unlikely in 1984 were an artifact of 20 adult male-s captured that of delayed in Jackson County in gm) were lower (f - 0.03) than live weights or collected It is doubtful resulted to in 1984. collection early courtship sampling. costs and may contribute in the final week of the month of 18 (R - 2,925 that male lipid reserves were larger in early April when body weights were lower. Early courtship lipid reserves County were also low in 1986. December resulted population. Heavy snow accumulations in November and in reduced lipid deposition 'among males in that Winter conditions severe and early courtship males collected of adult male sage in Jackson following in Gunnison County during 1986 were not lipid reserves were similar to reserves of the mild 1985 winter. Lipid Reserve Use During Courtship In both populations, during courtship. mobilized Following in response lipid reserves males in Jackson County County males used Sage grouse mobilization to the energetic of courtship demands of courtship. 66 g of of lipids was likely Energetic demands in male sage grouse are not known but are potentially Daily energetic urogallus) mild winters, 125-130 g of fat while Gunnison lipids during courtship. high. male sage grouse depleted requirements during courtship and are higher of male capercaillie (Tetrao are 2.1 times standard metabolic than winter existence requirements rate (SMR) (Linden 1984). �95 Invariant breast and leg muscle mass indicates were not used during courtship. During periods demand, birds are more likely to mobilize (Reinecke et al. 1982, Mortensen Heitmeyer 1985). investment differences the opportunity to correlate between conditions courtship in that in Gunnison 1986. Slower-display energetic investment County. Higher variance grouse in Gunnison similar between size and courtship County. in courtship in male 1ek attendance may have among some individuals investment courtship differences behavior and by male sage was not could not be attributed to in 1986, the display period with low lipid lipid reserves of males in Jackson were similar to reserves (4.1% of live weight). display was lower among males Due to severe early winter conditions Early courtship (3.6% of live weight) during early rates and lack of evening Although County entered size. similar mild winter of reduced energetic populations, reserve were observed between lek attendance County. lipid reserves. males in Jackson County that energetic lipid reserves provided reserve Despite in courtship behavior from inconsistant reserves. endogenous the 2 populations. could also be indicative unequal in early courtship were smaller among males in Gunnison populations resulted Siz~ in both study areas in 1985, lipid reserves Differences suggest lipids rather than protein could be affected by endogenous Interpopulation behavior of high energetic of lipids raised the possibility in courtship reserves et al. 1983, ~~yte and Bolan 1984, Male Display Rates and Lipid Reserve Male depletion that protein These results County of males in Gunnison fail to support the �96 hypothesis that slower display rates of males in Gunnison County were the result of lower lipid reserves. There are at least two explanations investment in courtship First, metabolizable energy of sagebrush in Jackson resources has been observed courtship in American Gunnison 1985). However, in crude protein County higher crude protein necessarily indicate that metabolizable in Gunnison County. Monoterpene in Gunnison County were higher sagebrush exploited Remington and Braun 1985). sagebrush in the Gunnison Dissimilar differences Gunnison Within a species, thermoregulatory investment by sage grouse in and content does not energy of forage was superior of big sagebrush than concentrations forage found in Wyoming big County (Chapter 1, of Basin may result in lower digestibility. investment in courtship. to interpopulation Male sage grouse in 25-30% less than males from Jackson County. costs are greater among small-bodied As a result of smaller body size, male County may have devoted a larger proportion to maintenance of body temperature. costs may have resulted in courtship than forage The higher mono terpene concentration (Peters 1983:71). their energy budget in (Chapter 1, Remington concentrations thermoregulatory sage grouse in Gunnison quality of food (Brodsky and body size may also have contributed in energetic County may investment content by sage grouse in Jackson County weighed individuals Energetic forage exploited by sage grouse in Jackson Braun 1985). County. to affect male energetic Sagebrush County. forage in Gunnison black ducks (Anas rubribes) County was higher exploited energetic among male sage grouse in Gunnison be lower than sagebrush Weatherhead for reduced among Gunnison some avian species have been observed Higher in reduced energetic County sage grouse. to moderate breeding Males of behavior of �97 dependent Higher upon thermoregulatory thermoregulatory explain why Gunnison remained costs resulting roost sites with overhead to higher and Bradbury from small body size may also cover at night. Males may have selected cover to reduce thermal conductance. in male attendance relative (Santee and Bakken 1987). County males did not roost on leks but instead in heavy sagebrush heterogeneity requirements in Gunnison thermoregulatory (1985) observed demands infrequent Greater County could be attributed in that population. attendance Gibson among male sage grouse during cold, windy weather when thermoregulatory costs were high. The Adaptive Significance of Male Lipid Reserves Among avian species, both the timing of lipid deposition size of reserves pressures accumulated are believed to be influenced (King 1972, Dawson and Marsh. 1986, Lima 1986). effect of lipid reserve size on courtship behavior the timing of male sage grouse lipid deposition courtship reserves lipid reserves immediately are likely adaptive. during winter and reserves prior to courtship. prior to periods is selectively deposition of endogenous 1983, Gauthier Vangilder to breeding demanding reach a winter-spring Accumulation of endogenous reserves prior to periods demanding (King 1972). activity. Avian of high energetic Male sage grouse accumulation fattening maximum reserves (West and Meng 1968, Mortensen is likely an adaptive an Male sage grouse accumulate et al. 1984, Krapu et al. 1985, Mainguy et al. 1986). Although and the size of early favored in bird species demand has been widely observed by selective was not apparent, of forage scarcity or energetically activities and the et al. and Thomas 1985, of lipids prior prior to an energetically �98 Size of avian endogenous selective pressures. positively resource Marsh 1986). population Traits and Thomas lipid reserves winters. Early courtship or forage expressed to stabilizing among individuals Intrapopulation suggest a stabilizing similarities selective were 4.1-4.2% influence and 1986. Early courtship among males within lipid reserves sampling Early courtship in Gunnison periods costs during the courtship county males obtained respectively metabolic season. Assuming (Ricklefs approximately from lipid metabolism rates for gallinaceous a caloric 1974), Jackson conversion of and Gunnison Standard birds can be estimated requirements were approximately demands from body mass body mass in 1986, SMR 143 and 118 kcal/day respectively. season energetic (Table 2.2). of the total energetic during courtship. Given the early courtship for display County males in 1985 1,170 kcal and 590 kcal of energy (Zar 1968). county males, while of male sage grouse were not large to meet a major proportion lipid metabolized in were not highly variable sufficiently 9.0 kcal/g mild of live weight in either population lipid reserves on early years following were 5.4-5.5% of live weight in a in early In each population, were similar between reserves with large County males after the mild 1983 and 1985 winters reserves to be 1985, Dawson and risks associated size in male sage grouse. courtship Gunnison size is believed demands that are subjected are similarly lipid reserves lipid reserve Jackson predation (Mayr 1970:175). courtship by stabilizing size may be limited by greater maintenance or increased pressures reserve energetic (Evans 1969, Mainguy (Lima 1986). selective may be affected endogenous with seasonal Maximum requirements reserves Minimum correlated scarcity reserves Using Linden's in capercaillie for Jackson and (1984) estimate (2.lx SMR), total �energetic demands during a 6-week display period were approximately 12,600 and 10,400 kcal/male counties, respectively. small proportion « Therefore, fat metabolism 10%) of the total energetic grouse during the courtship An adaptive for sage grouse in Jackson advantage depleted reserves to lipid deposition early courtship may be rapidly mobilized likely greatest. selectively attendance success to Lipid short period of in courtship is of lipids would be success during female of energetic demands of courtship. reserves that Size of early to meet energetic short period of female attendance is primarily If males demands when male determined. CITED R. T., and C. D. Ankney. energetics Ankney, accumulation reserves may only be adequate reproductive A1isauskas, investment was affected by the availability during the temporally LITERATURE . during the relatively if male reproductive could be used to meet energetic courtship to meet a large proportion short period. when male energetic Pre-breeding favored may exist even though reserves would be adequate demands during a temporally peak female attendance only a needs of male sage demands of sage grouse courthship. lipids rapidly, meet energetic could provide period. the size of lipid reserves was not adequate of the total energetic and Gunnison C. D. of reproduction 1985. in American 1977. The use of nutrient lesser snow geese Chen caerulescens 55:1984-1987. Nutrient coots. reserves reserves and the Auk 102:133-144. by breeding caerulescens. male Can. J. Zool. �100 1984. N~rient reserve dynamics and molting Auk 10k:361370. brant. 1978. '(:and C. D. MacInnes. _____ of breeding performance selection reserves and reproductive Auk 95:459-471. of female lesser snow geese. 1977. Beck, T. D. I. Nutrient Sage grouse flock characteristics in winter. 41:18-26. J. Wildl. Manage. _ __,.",--_,and C ."E.. :,Braun. 1978. Weights and habitat of Colorado sage grouse. Condor 80:2.41-243. Brittas, R. 1984. Seasonal and annual changes . lagopus. Swedish ". w~:llow grouse, Lagopus Br odsky, L. 11-,,! and.R .•J. Weatherhead. .const ra.Inrs 2n courtship 1985. in wintering in condition of the Finn. Game Res. 42: 5 -17. Time and energy American black ducks. Condor 87..:~3-36. Dawson, goldfinch Physiol. Dobush, 1986. W. R., and R. L. Marsh. and the possible G. R., C. D. Ankney, extraction 1980. R. D. role of temperature in the American in its regulation. and D. G. Krementz. time, and solvent 1985. The effect of type on lipid extractions Can. J. Zool. 63:1917-1920. of snow geese. Drobney, fattening 59:357-368. Zool. apparatus, Winter Reproductive bioenergetics of wood ducks. Auk 97:480-490. Dugan, P. J., Winter P. R. Evans, L. R. Goodyer, fat reserves in shorebirds: levels by severe weather Erikstad, K. E. 1986. and i~cubation and N. C. Davidson. disturbance conditions. Relationship rhythm in willow 1981. of regulated Ibis 123:359-363. between grouse. weather, Cinclus body condition, 9:7-12. �101 Evans, P. R. 1969. Winter fat deposition yellow buntings and overnight (Emberiza citrinella L.). survival of J. Anim. Ecol. 38:415- 423. Gauthier, G., J. Bedard, J. Huot, and Y. Bedard. accumulations 1984. Spring of fat by greater snow geese in two staging areas. Condor 86:192-199. Gibson, R. M., and J. W. Bradbury. sage grouse: phenotypic Ecol. and Sociobiol. 1985. correlates 1985. of male mating success. ~ and C. E. Braun. trapping sage grouse in Colorado. M. E. Hjorth, I. Wintering strategies Ph.D. Thesis, Univ. Missouri, 1970. reference Hohman, W. L. 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SPSS Inc., Chicago, 230pp. Peters, R. H. 1983. The ecological implications Cambridge Univ. Press, New York, N.Y. Raveling, Harvard Univ. 453pp. A., S. Unander, M. Kolstad, changes Norusis, Mass. species, and evolution. D. G. 1979. 329pp The annual cycle of body composition geese with special reference 96:234-252. of body size. to control of reproduction. of'Canada Auk �103 Reinecke, K. J., T. L. Stone, and R. B. Owen, Jr. 1982. carcass composition Maine. Condor 84:420-426. Remington, T. E. 1983. and energy balance Food selection, Seasonal of female black ducks in nutrition, and energy reserves of sage grouse during winter, North Park, Colorado. Colorado State Univ., Fort Collins. ________ , and C. E. Braun. 1985. North Park, Colorado. Ricklefs, R. E. 1974. M.S. Thesis, 89pp. Sage grouse food selection J. Wildl. Manage. Energetics 49:1055-1061. of reproduction 297 in R. A. Paynter, Jr., ed. in winter, in birds. Avian energetics. Pages 159- NuttallOrnith. Club Publ. 15. Santee, W. R., and G. S. Bakken. blackbirds costs. Vangilder, 1987. (Agelaius phoeniceus): Social displays sensitivity reserves of premigratory West, G. C., and M. S. Meng. fat and relation ptarmigan. Whyte, R. J., mallard Wiley, R. H. 1986. brant during spring. 1968. Seasonal Auk 103:237-241. changes of fatty acid composition Nutrient in body weight and to diet in the willow Wilson Bull. 80:426-441. and E. G. Bolen. body condition. 1973. pattern. birds. to thermoregulatory Auk 104:413-420. L. D., L. M. Smith, and R. K. Lawrence. Zar, J. H. in red-winged Impact of winter stress on Condor 86:477-482. The strut display of sage grouse: Behaviour 1968. 1984. a "fixed" action 47:129-152. Standard metabolism Condor 70:278. comparisons between orders of �104 Prepared by Approved by ~ W. ~ Jerry W. Hupp ~ ~-:;.t!a~~::.,:.-_____::C£=-.-I.~:.....e.....~_.:..:_ Clait E. Braun _ �JOB PROGRESS REPORT Colorado State of: Project: W-152-R Avian Research Work Plan: 3 Job Title: Response of Selected Avifauna to Prescribed Burning in the Big Sagebrush Type Period Covered: Author: Job 17 01 January through 31 December 1987 Ernesto J. Hernandez Personnel: E. J. Hernandez, Colorado State University and C. E. Braun, Colorado Division of Wildlife ABSTRACT Preparations for this study were initiated by C. E. Braun in July 1986. Consultations were held with personnel of the Bureau of Land Management and a delay in controlled burning in the Deer Creek area, North Park, Colorado was requested. Treatment (Deer Creek) and control (Railroad) leks were selected. Review of literature was initiated and study designs were discussed by C. E. Braun and D. C. Bowden with personnel of the Colorado Division of Wildlife and the Bureau of Land Management. Despite effects on study design, a portion of the treatment area east-southeast of the Deer Creek Lek was burned in September-October 1986. Male sage grouse (Centrocercus urophasianus) distribution during the 1987 breeding season was ascertained for 10 radio-marked birds at each the Deer Creek and Railroad leks. Distribution around leks was not random. Distance from lek, to feeding and loafing sites varied from the.immediate vicinity to 2.9 km , Vegetation at use sites averaged 6.1% grasses, 8·~6% forbs, and 31.4% shrubs. Shrubs were primarily Artemisia tridentata vaseyana with a mean height of 21.8 cm. Peak lek attendance of males occurred on 5 and 21 April with 23 and 31 birds at Deer Creek and Railroad leks, respectively. Surveys of passerine birds in these areas were inconclusive because of the large number of birds that were not identified. The planned Deer Creek Wildlife burn occurred in Fall 1987 and resulted in up to 70% vegetation removal. ��107 RESPONSE OF SELECTED AVIFAUNA TO PRESCRIBED BURNING IN THE BIG SAGEBRUSH TYPE Ernesto J. Hernandez P. N. OBJECTIVE The objectives of this study are to document the response of sagebrush-dependent avifauna to prescribed burning in the big sagebrush habitat type in North Park, Colorado. Specific objectives were to: 1. Assess the impact, if any, of prescribed burning on breeding season habitat selection by male sage grouse. 2. Estimate changes in relative abundance and diversity of passerine birds in response to prescribed burning. Hypothesis HOI: Male sage grouse use each habitat class in proportion to its occurrence in the total area. H02: Prescribed burning does not alter selection of habitat class by male sage grouse. H03: Relative abundance and diversity of selected passerine birds do not change following prescribed burning. SEGMENT NARRATIVES 1. Review available literature concerning sage grouse, composition of sagebrush, and techniques adaptable to studies of galliform birds. 2. Review available literature concerning burning of sagebrush rangelands. 3. Capture up to 30 sage grouse within the treated and untreated areas during March through May 1987 for attachment of tail clip or poncho-mounted radios. 4. Relocate radio-marked sage grouse from April into August for observation of patterns of habitat use. 5. Conduct up to 12 counts (6/lek) of males and females on the treated and untreated sites during April-May for observation of male strutting display rates and fluctuations in female numbers. 6. Locate nests of radio-marked female sage grouse within the treated area and those dispersing from the study site during May-June. Determine clutch size, nesting success, and nest site characteristics (i.e., vegetation composition, height, cover). �lOB 7. Periodically (3-5 days intervals) locate radio-marked hens after hatching to estimate brood survival from hatching until radio failure or 1 September, and to observe patterns of habitat use. B. Measure vegetation structure and composition on treated and untreated areas from June into August. 9. Establish at least 4 permanent line transects on the treated and untreated sites for estimation of breeding bird response to burning as to species composition, species richness, and relative abundance from April into June. 10. Use night lighting techniques to capture adult and yearling male sage grouse roosting on leks during March-May. Trap and band 200 males and at least 100 females within North Park from March through May. Obtain body weights from sage grouse at time of capture. 11. Collect population data through use of wing barrels and check stations during September-October. 12. Compile and analyze data and prepare progress reports. pertinent findings at appropriate scientific meetings. Present DESCRIPTION OF AREA The Deer Creek and Railroad leks are in T7N, R7BW, SW1/4 S31, and T7N, R80W, SWl/4 S2, Jackson County, Colorado. A physical description of the study site was presented in the Environmental Assessment prepared for the Deer Creek Wildlife Burn in August 1987 (Appendix A). METHODS Sage Grouse Capture and Instrumentation Male sage grouse were captured during April using spotlights and long-handled nets (Giesen et a1. 1982). Captured birds were fitted with tail-clip or poncho-mounted radio transmitters (Amstrup 1980). Radio-marked birds were located every other day beginning 9 May continuing through 1 June to evaluate seasonal habitat use. Shrub Structure and Vegetation Composition Measurements of vegetation at observed use sites were taken using Canfield's (1941) line-intercept method. Thirty 15-m transects were analyzed at the Deer Creek site. All sage grouse leks in North Park were counted during April and early May between 0.5 hour before and 2.0 hours after sunrise. Frequency of counts varied from once every other day to once every 10 days, with the study sites receiving the highest number of counts. Counting continued until 11 May when no birds were observed attending leks. Sage grouse were captured for banding in all areas of North Park. �109 Habitat Use Empirical data (i.e., telemetry locations) were compared to planimetric estimates of habitat classes within a 2-km radius of the Deer Creek Lek. Boundaries between different classes, arbitrarily designated A, B, C, D, and E, were delineated from aerial photographs of the area on the basis of vegetation density (Marcum 1980). A chi-square test of homogeneity (Mendenhall 1971) was used to test the hypothesis that male sage grouse use each habitat class in proportion to its occurrence. Breeding Bird Surveys Four 800-m transects were marked in the Deer Creek Lek area. Following 5 unsuccessful surveys, these were replaced in June with 7 fixed-count stations. The stations were 200 m apart along a north-south axis in observed sage grouse use areas. Three-minute counts were made at each station once every other day between 0530 and 0730 from 1 to 10 July. A l-minute rest period was allowed at each station prior to every count. This census method followed Reynolds et al. (1980) variable circular-plot method. One transect was marked in sage grouse feeding and loafing areas in the Railroad Lek area. Deer Creek Wildlife Burn A Burn Plan (Appendix B) and Environmental Assessment were prepared and .submitted for review. Metal stakes were placed at each of the 4 corners of the proposed burn site. The plot measured 1,221 x 303 m and encompassed an area of about 37 ha oriented along a NW-SE axis about 60 m east of the Deer Creek Lek. Sevent.y-five percent of the recorded telemetry locations for this area were contained within the plot. RESULTS AND DISCUSSION Twenty male sage grouse, 10/lek, were captured between 2 and 23 April. Sixteen solar-powered transmitters and 4 battery-powered tail-clip radios were divided equally between the 2 study areas to instrument the captured birds. Twenty-eight locations were recorded in the Deer Creek area between 9 May and 1 June. Locations were not systematically recorded prior to that date. Of these, 25 were within a 1,600 x 300 m strip immediately east of the 1ek. Two locations were 1.4 km south and a single location was 1.5 km southeast of the lek (Fig. 1). Six transmitters were recovered from birds marked at this 1ek (Table 1). Sixteen locations were recorded 2.9 km southeast of the Railroad Lek and an additional 7 were recorded 0.8 km east of the 1ek (Fig. 2). Two of the latter were immediately following morning 1ek dispersal and these sites possibly constituted staging areas prior to daily movements away from the lek. Two tail-clip radios were recovered in this area. The status of radio-marked grouse in both study areas is summarized in Table 1. No attempts were made to locate radio-marked birds during the last quarter of 1987. �llO . t-."" - c' -', tz: "<, e, ''''. 8405 I-------~--------~------+ -< ' \ ", '- , ,) 25 ,, 29 , ~ " "~ "'~3i'+_---',..... • ~~ : .•. ,. 36 ~ . .~~\)I ..•. .::::.:::;.:::.::::. ,. " " v I' ", 1/ " /: /: •• n , v n • '_ II \ .,.....1 6 , V' a "u \I If " e>- " ~, I' ,; " " 1/ 1/ \ -. ,-, \ ~~o ~ B:58;'\-_ - 4,,:- ;.../" "t""·,\... i Fig. 1. Male sage grouse use sites, Deer CreeK Lek, Jackson County, Colorado, spring 1987. �Table 1. 1987. Status of radio-marked male sage grouse in North Park, Jackson County, Colorado, 30 September Frequency Radio type ABe Band Capture site (lek) 150.811 150.836 150.862 150.925 150.951 150.966 150.979 150.999 151.039 151.236 151. 256 151.268 151.387 151.417 151.464 151.505 151. 525 151.545 151.564 151.825 Poncho Poncho Poncho Poncho Poncho Tail clip Tail clip Tail clip Tail clip Poncho Poncho Poncho Poncho Poncho Poncho Poncho Poncho Poncho Poncho Poncho 12+ 12+ 112+ 2+ 2+ 2+ 2+ 2+ 11112+ 12+ 2+ 215 119 214 120 213 121 117 116 792 115 123 186 188 187 212 131 759 122 135 171 Railroad Deer Creek Railroad Deer Creek Deer Creek Railroad Railroad Deer Creek Deer Creek Railroad Deer Creek Railroad Railroad Railroad Deer Creek Railroad Deer Creek Railroad Deer Creek Deer Creek Date of capture 23 05 23 05 22 06 04 03 03 02 18 16 21 21 22 13 15 06 14 15 Apr Apr Apr Apr Apr Apr Apr Apr Apr Apr Apr Apr Apr Apr Apr Apr Apr Apr Apr Apr Date of last observation 07 No 02 No No 07 No 25 24 27 12 19 25 27 02 26 02 26 17 17 Ju1 observations Ju1 observations observations Apr observations Apr May Hay May May May May Ju1 Aug Ju1 Aug Apr Apr Status Recovered, shot 13 Sep Recovered, 09 May Active Undetermined Recovered, 09 Maya Recovered, 28 Mayb Recovered, 18 Mayb Recovered, 18 Mayb Recovered, 26 Mayb Shot, 13 Sepc Undetermined Undetermined Undetermined Undetermined Active Active Active Active Recovered, 26 Maya Recovered, 12 Mayb aTransmitter attached to carcass. bTransmitter not attached to carcass, nor any evidence of carcass. cLocation of radio unknown. I-' I-' I-' �112 ., I ' eterson ;"i:~aru. , ~ ~:. __ ._..._--- =:.-: :: ~ / I .::::-::;;:::.=::=:::.::=:::... ' 36 I 31 I I f'.:: <_: __ T.;_;.;....:::8::;....:cN~.:._ +8°-._.,.....~;----------------- --1- ~5:.:.:-------"H,-ac-::kT:le:":'"Y.-5;;;:: I T. 7 ['" • J 1 ----.~~. =" •..• Ranch R.80W.! ~.79 w. : / ~ o I ------- 2 .,»: f 0.,"- a r- ; • eO RAILROAD LEK I 1 • • .0 ~. '. 1.,/ 6 ,, I c I I i " _ (,':'--- __________ , =".:7i-+· __j.,__ I +8 .•. .,50 _~=::;c.=.,...". - [>: i ~ " ~o , .0' ~ J:- /7 \,': .' 12 J , y' .. ':< - .- _ .. --- - - - ._-_ - - - - - i I •• e: ;' . 7 ! ,~ • i{;lOch ; - •• r- "Gr,,( . ( ':. ,..;. -- <, ) .;:/ , 11 .' t ( ~./.' - +b.d, ,.:, -'-"'---.,_...._tt_"D •..,--J • • \ \ ?1'" __ "'I . ',,_ c- Fig. 2. Male sage grouse use sites, Railroad Lek, Jackson County, Colorado, spring 1987. �113 Analysis of 30 vegetation transects in the Deer Creek area gave the following composition: Grasses 6.1% Forbs 8.6% Shrubs 31.4% range 1.5 - 13.3% range 0.8 - 16.8% range 17.8 - 54.7% Mean shrub height was 21.8 cm (range 11.7-35.3 cm) with an average of 19.5 plants per transect. Shrubs consisted of Artemisia tridentata vaseyana. Peak male attendance displaying; peak hen observed. Peak male birds observed. Hen at the Deer Creek Lek occurred on 5 April with 23 birds attendance was recorded on 21 April with 19 hens attendance at the Railroad Lek was on 25 April with 31 attendance reached a maximum of 48 on 7 April. Telemetry data indicated that male sage grouse did not use each habitat type in proportion to its occurrence within a 2-km radius of the Deer Creek Lek as all locations were within type B habitat. Planimetric proportions estimated for habitat types A-E were 0.1761, 0.3211, 0.3225, 0.1749, and 0.5400 respectively (Table 2). The calculated test statistic was 40.7 and the chi-square value (0.01 significance level, 4 df) was 13.2767. The hypothesis of homogeneity of habitat use (HOI) was rejected. A total of 84 passerines was recorded during the Railroad Lek surveys. Of these 69% were identified and classified by species and distance from observer. Distance estimates were also made for 26 birds that were not identified. Eighty-six observations were recorded in the Deer Creek Lek area of which 55 (64%) were identified and classified (Table 3). The proposed Deer Creek Wildlife Burn was conducted between 21 and 24 October. Sagebrush removal was estimated at 60-65% of the southern part of the area and <50% of the northern part of the area. Assisting with the burn were personnel from the Craig and Kremmling offices of the Bureau of Land Management and the Colorado Division of Wildlife. Most of the burning was accomplished by using drip torches. Subsequent attempts to increase the burn efficiency were made by repeatedly crossing the burn site with a propane torch. These took place over a 3-day period and were only partially successful. Total sagebrush removal following the use of both methods was <70%. CONCLUSIONS Telemetry data from the Deer Creek area suggested that male sage grouse distribution was not random and may be influenced by vegetation structure and composition. Proximity to the lek did not appear to be important as evidenced by comparing distances recorded from the treatment and control sites to feeding and loafing areas. Although the Deer Creek habitat use data suggested that the hypothesis of homogeneity (HOI) could be rejected, without more locations and extended (2-3 years) pre-treatment observations it was not possible to establish whether the observed feeding and loafing areas were consistently used during consecutive breeding seasons. Continued observations at Railroad Lek may provide information on this question and analysis of habitat preference for that area will become more important. The effects of the 1986 Deer Creek burn on habitat selection, if any, were unknown. �Table 2. Observed and expected values for planimetric estimates and radiotelemetry locations for male sage grouse, Deer Creek Lek, Jackson County, Colorado, 1987. Habitat class A Planimetric proportion Sage grouse locations Totals C B D E Obs. Exp. Obs. Exp. Obs. Exp. Obs. Exp. Obs. Exp. Totals 17.6 0.0 13.8 3.9 32.1 28.0 47.0 13.1 32.3 0.0 25.2 7.1 17 .5 0.0 13.7 3.8 0.5 0.0 0.4 0.1 100 28 17.6 60.1 32.3 17.5 0.5 128 I-' I-' .j::- �ll5 Table 3. Survey of passerine birds on the Deer Creek and Railroad breeding bird transects, Jackson County, Colorado, 30 June-lO July 1987. N Species observations Deer Creek Sage thrasher Vesper sparrow Western meadowlark Horned lark Brewer's sparrow Unidentified Subtotal 10 24 8 3 10 31 0-10 Distance (m) from observer 51-100 26-50 11-25 2 4 1 10 4 2 1 2 13 3 3 1 3 1 9 8 8 2 4 16 86 Railroad Sage thrasher Vesper sparrow Western meadowlark Horned lark Brewer's sparrow Other Killdeer Common raven Swainson's hawk Brewer's blackbird Unidentified Subtotal 21 12 7 7 7 1 1 1 1 26 21 6 7 4 5 1 6 10 1 1 1 10 84 Surveys of passerine birds were inconclusive. Observer inexperience was an important factor as it resulted in a large proportion of unidentified birds. The methods selected for the surveys were consistent and reliable; differences in rate of travel as well as distractions from noise made during travel were eliminated by making counts from fixed stations. LITERATURE CITED Amstrup, S. C. 214-217. 1980. A radio collar for game birds. J. Wildl. Manage. 44: Canfield, R. H. 1941. Applications of the line intercept method in sampling range vegetation. J. For. 39:388-394. Giesen, K. M., T. J. Schoenberg, and C. E. Braun. 1982. Methods for trapping sage grouse in Colorado. Wildl. Soc. Bull. 10:224-231. �116 Marcum, C. L. 1980. A non-mapping technique for studying habitat preference. J. Wildl. Manage. 44:963-968. Mendenhall, W. 1971. Introduction to probability and statistics. Duxbury Press, Belmont, Calif. 466pp. 3rd Ed. Reynolds, R. T., J. M. Scott, and R. A. Nussbaum. 1980. A variable circularplot method for estimating bird numbers. Condor 82:309-313. Prepared by §Jt,~ 9. ~CU\~ Ernesto J. Hernandez Graduate Research Assistant Approved by -=-~a..,.:.· -;~;---;';-~_ ..!...~ _ ___: Clait E. Braun Wildlife Research Leader _ �117 APPENDIX A PRESCRIBED p ~.~c. FIRE PLAN .... G..c..?~.k.... J".:L.),..:;:I.l:i,f. ..~ .....~.t"A.c.n. Burning 15.c.~n.Jn.JJ:i,.n.9 R.~.:?.9.l,lc..c,:::~ Ac.~.1?. Unit Resource .............. _._G.C1?:i,9 _ Area . District Pre par ed by: .... I.~c.r:X.... J"'.,_ ... H9.t..t..J ..~.:?. _..._. . . . . ..' Colorado State Forest Service Reviewed Reviewed by: ~ cu1i'<l(j Area I2~L .. Mal;'~;~;;'jlr. The approved Prescribed Fire Plan constitutes the authority to burn. No one has authority to burn without an approved plan or in a manner not in compliance with the approved Prescribed Fire Plan will be fully supported. Personnel will be held accountable-for actions taken which are not in compliance with elements of the approved plan regarding execution of the objectives in a safe and cost effective manner. This project is rated COMPLEX INTERMEDIATE _.~ .. NON-COMPLEX, pursuant to prescribed fire guidelines Estimated Approved Cost Per Acre: by, ~ f)~t: $.::? ,...QQ....1:: q ..._l'.4-_, ...:?'.Q. /%~ Distri~Manager �, ' ;-t,;. ",::118 ~ SERVICE Steamboat Springs District P,O, Box 713657 Steamboat Springs, Colorado 80471 October 12~ 1987 Deer Creek Wildlife Burn Narrative Depending on the wind direction'the day of the burn you should start on the leeward side of the block and in a corner and black line 15-20 feet in- from the beaten line. This should be done all along the leeward side or sides of the block. Paying close atteJil:tjonito~~\'lind direction 'you can take progressively wi der strip's with the firing crew working from the leeward side of the block toward the windward side. �119 Proj8ct: ~ P~oject * DEER CREEK WILDLIFE BURN Location T7N R78W ~ County: Sec. 30, 31 ~ 32 Jackson Purpose of the burn: To eliminate sagebrush from saqeqrouse This is a cooperative burn between DOW and BLM to evaluate the-impact of rescribe burnign on seasonal habitat on sagebrush. A. Haza~d Reductiorl G. Silviculture c. ~3it e F'~ep C'<T "'.t i on ~. __._1?.I~_!?.P_.1>~§:.LP.gI_=i_.I!!..~.t~.I .:.; "./ \,' \/ A~AnAA \; . _ .'./ _ ~. Insect/Disease F. Range tJ.. F:p ;::':C i ~~.J. i:1~).ni pLt 1 .:7.).1:.i I-:::;rl H. Oth2!"- C3P2Ci i:y. ) Fire Objectives: sagebrush throughout the burn area. The _ _ I) .. II. Evaluation lek COlltrol _ Management T2chniques Division _ . ._... . . .. . 1) Kill 90% or more of the (Give Description). of Wildlife will evaluate the burn using their or,·.Jncrii.:e,i~.:i. ;. " * Ill. .~. Burning Permit t:ol_lI-n~ ["4 __ ._- Fall ------------------_._-_._-------_._-------------_. --------------------------------------.. .... ...- ~..~ ) ' .' . �120 ~ A. Type Presc~ibed of Burn s~gebrush burn ·r 1,:::-.( l...._J.:.. Fuel (T I -5':) .__ )L~ ..__. (s) j·lode.l D. Fuel Loading (TA) E. Fuel Continui~y varIes F. Fuel ~;c",\ttC'r ·:?o Arrangement 1. Fuel o - 1/·4'1 with light vary understory grasses. :1. :20'1. :- I(:'! II '-:' DE: 1-;: P 'I::. h Cj -;: + or ranqe I) !.). { r'- ,';:tr-j q 'i~ F~' N/(~'I ["f'-;:;".n~:'i.gi"::.:'rnE'nt, conditions, trends, E:(j'C t orn S 1 op .;(-c) to 50% ":--., :1. bi 10% brush DistributiGn~ :l / .~.~ -.._ ~;" ._ G ~,: i ["'I C 1 Ltd (? 1- ":".n~J;2 present t i ort OJ Tor2qe production, e d.r'';'~·I.l\;i':; i·:::;. annU21 i r.-~: c:;r rn·:1 85!)(} .. ~) --~.3~.~ on Slop2 ;_:C)r·;_:;idl_::;I'·.:~.tj_Dn·;:; --------- N/A -------------------------------_. Due to fuel •• --.-.-------- _.__._.__ ?_b..Qy_~_?_y.~E.~e_::.~~rl_cl._.~p.~_~c!~_.:. continuity, :o. w i Ll. need • _ . _ -----------------------------------------------------------_ . ~ . . ." ..;~. �121 v. Durn Prescription T i en :.::: •..., .., •. , "J .{.: :_, ~::;. }' 3. uays Since Measurable . Moisture .-:.r:::: "::"','_' cc- •....' .. cl~ar du: ;:'::"i< PC:'Ct.E';(] r :i. nq to p2r~ly b uvn i. nf:j P(,·:,'j--'~ od ~ although cloudy! b) Fire Behavior flame It E.' lengths in .----_ .._----_. __ .__ .__ ._-_._._ ..._ .._-_ .. w i t h fronts w i nd s associated would be more desireable. FL, D€·::~:;i:-·E·'d 'iesd: f::;Ur-n h:c?·=:,:_:.i.·c.s Due to the time of the year, to burn the entire unit Hill be attempted. no fronts an attempt Narrative acceptable -_ _----_._ .. .. _ .._--._- ---._---_ .... __ .__ ._--- --,_--: , J, Ac' :._.- --_-_. __ ._---------_._ ..._--._ : ------_ ., 85 of .-, .LL i-ltJ. ITI i d i t. ~l .-:: 1''::; 15 c:: c· !..~ -j, II '. ; i !.._ .;_ -_._-----:------------- .-. i I I I I .. �122 : CI :"', -',' ., _--_ ._.-.-- _ _-'.-._ ..- _ .. : _-_, .._-----_ _ ....}_?2~_.__.::'-'-.,-~._-.. _?_~.~__. _ sage L...1 \.:C: 35% .l ()" ; , ;.•..} 1. .2t) ..:~ " 3. Stabil~ty ~2ctor '0:' ]. .... -;- ~:·;n]. 1. wind .... ";.... ; ,... . in i ].1 :..:.! j_ -::~t:,I~.:;~._:..;_:: The permittee C:i !<:;;.i n -:: / /~. Line ~Q -i ·,·.· .••1••••• \ J. '_I ::}j. t i::': (:"i r, t t"; ,:~ L '-~;;. .: : -'.-.\/ : - c;.:':'i.U concerning the use of water -f r: CJ en '!:,', h .::.:.~.:ur n to be contracted if';:i.]. E·:' will need l_. __ . : : " Construct •...._. .1- ,- . ',' ::"_._'; i,··1 C'Il ...!j. Prepar~tiGn i., .~":_';. _ J'. f._= _ i_,'. _ N!A _1... _....• '1_·· .: ;,. ,._"', . " ··1·_-:::' _ '_'. ':~' __ _...,'....~.• ,,-,·1 u _- _---------_._._- I·· C'" ••... __ j -- --_--- -.; 1,'.1 L'r- 1• _._----_-.- \/i:::' I" q ~.~:-..: , 1 • fii;::l'l: E't£5) • D !_:.c. ';;.-;~·s· T. I ---------------------- ------------------------------------------_._---------------------.--_ ....• ----_.-_.--_. 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Qurniny ~':3 • l-;(J 1. ,j i .r, '._I I ~ _ 1~ I~ {-l -1 1-:1 .. . _ ------------------------------------------------------------------------------------------------------------------------------------_i_~__9:~t_i~_iE~_t_~_~_: . ·,o ; : _: :,'.j i.:. common to al~ __ '--.': . .-, - •• !.... __ ,,_. .__. __ "C ,_ •••• • ::_~(~ H. _ . •••••••• 0 •• i ..:.t:.::.iI I ._.__ . . -------------_ ----------'.! v~hi~L~~. "\, -' �.. 124 1"', •.•,' ' •• ".- . :i .;. \/ s: ~::,:~ .1. • • '. j i ! -! cJ . i.._: C) n ,t..;) C t; COf:lP J. et {2d (initi.:"ls Jackson Ca. ~~ar 723-4404 i-" __ i_.,J...,J 2. Fire • Department ------------r-'! t., ,L.._! !.,.I ! -/ ~2.:~-_.,_','~.-'.- -------------- �125 " i···.ic.,j··· t ~'! .: .. i ~::t.:...., .... C'·: . i ·.••1 ~•• " :3 • C)t. h ('-2 ;, .. 'c.. West2~n Slope Fir2 Center 2~5-4088 Actual Obs2rv~d/Measur2d I~~ni [)C). )-.rs :: (:n _ ~GPY if avail.) t; i inc r::.' Forecasted W2athe~ (Burn Day) (Attach actual forec23t ~~il;I-I~_ ------------------_._------------------------------------------- ----------------------------------------------------7---------------------------------~---------------------------------------------------------------------------------------------------t,c: t. ;..:.·~;).l (F'CJll ~;.Jf:::' E." D •.... -!:L nq t roo, '7.~ 1""- ( 1::; u. r- n i",! i q j'-, 1: ./ I).~';\ .~/ ) f' c:' (- i, c} d ) __.,,_._ __.. _ _ ..~.. . ------------------------ ----------------------------------------------- . "r:./~ �126 .i. Holaing Plan 1 i nr:::s:. dU.r·· j. nq will be *Threat 'j 1_; .1. -:::1.,.... .- i t: and ~sed to patrol Contingency Fire '-~- '.-..\_, ~-.' :-...:. ,::, - linG 23 black line be fence Trigger F·: 1. i ....':":, i.':.p Plan and Property would t -::':.1 no life threatened, lines. Mechanisms and Confirmations Constant t~i:..tl"· 1'"1 the progress. of Life *Escaped . ,!":, in reserve Fire thrc2ten2d __ _,_ _!. ;_. }.i ESC~P2d ':.:,:j'L. ~ ! Narrative held operations f:.::·l"l radio contact should be '! "-'.'.1. -------------------------------------------------------------------;'·(1dditi.Cln.::ll E~:;c-3.pe :3uprwession F\f2~.GU;--·cCCj !:.iit:·, Loc,,:d:iGrl Lo bc::' C=."dl&~d for Fire �127 .' c:::· .•...·-.• ...1 ·; 1'.-,;;',11' " -,:.:..,. .. .~ :i .:;.~<:.; ,-.ill s: '•••• 'Il ,,. . , , '_1 n -----------------------------------------------------~-----------]_ J. ·1 -;~ J. -_'" .• !:.:;' .L ,_) '" �128 +', i.::) I ~Jn i 'i:. i t: n :~:~ f.:! q U. (-:~,r'i c: ~~:, .:~;. n (1 o \/;:.;:. t- I .;:;" '/-::;; ) ;-: i: J_ d j. r', g ~~., 1 .:;(;::_ c: :T1 C:;', r-;-;:: >1.:;;\ p ~:'. :,- . .. ", ',~ . ';._:.. ~~ :~ _ �129 \ \ ----~----~7_----+------ _ 8405 25 29 " ~ __:_~:·':8.'?6 I,.• " _-' . "T. 7N. ,, \ I I .. , ~~J6 • , \', ."0: I I '~:. ,• • ..• T. 6 N. I' I I . • • ..• •, c "" I / I , I' • I f , , , .. ·•, • I I • •• ,,I • • • ,, . 6 -~ 5 .." •· _. i,J... _--.~ ~ ~~-~ r toO - --'" ' .... S •••. 'lLW'Ay ~-', .:.S Raervoir ~OO~ " . ~.':'.... ",' •.. • •••• ##- •••• '-:-» .';541 • . ~ ' , .•• •• ,,",.- ' • J .•. t •• .' \' ~ L_ .. -",-~-,-, I .' I· ~ ,'b" \.. I .",,'" ~o •.... ." . '" I I ,- 't.. ~ . •• ~ '. \ ~ _.#( .- Appendix I - Location of the Deer Creek Wildlife Burn, North Park, Jackson County, Colorado, Fall 1987. (From USGS 7.5' series, Owl Ridge Quadrangle Jackson County, Colorado, 1955). ...•....•. ._ • �;' 130 APPENDIX B DEER CREEK WILDLIFE BURN Background This environmental assessment will analyze the impacts of using controlled fire to remove sagebrush structure on one site in North Park, Colorado. The objectives of this action is to evaluate the response of sage grouse to burning of habitats used during the breeding season. I. Purpose and Need The purpose of the proposed action is to remove all of the above-ground vegetative structure at observed sage grouse use sites. This is desired to evaluate the impact of prescribed burning on seasonal habitat use by male sage grouse. Accomplishment of this objective will provide information that will aid in developing a holistic management plan for sage grouse and big sagebrush habitats in Colorado. II. Alternatives A. Proposed Action A single unit of approximately 92 acres is proposed for burning in Fall 1987. The action would consist of constructing fire lines around the unit and strip firing into the wind. Firelines would be constructed using a rubber-wheeled vehicle pulling a rotary brush beater. Since it is desirable to have fire lines 24-30 feet wide, it will be necessary to make 3 passes with the brush beater. A brush rake will be used to clear the cut brush and pull it into the burning unit. Fire lines will be constructed around the entire unit. Firing techniques will consist of people on foot or in a vehicle lighting the fire using drip torches. The area would be burned by first firing the downwind edge of the unit to create a black line. The next strip would be fired 10-15 feet upwind of the first. Strip firing would continue in this manner until the entire unit was burned. Post-fire management of the area consists of resting the area from grazing by livestock for a minimum of 2 growing seasons to allow for establishment of grasses. No post-fire seeding is necessary, since the area currently has a good stand of perennial grasses to supply a seed source. A 60-100 m wide vegetation buffer zone is desired along the periphery of the treatment area to assure adequate snow deposition and moisture, and to help control wind erosion in the treatment area. A total of 92 acres is identified for burning as shown on the attached map (Appendix I). Within this burn site will be 3 circular plots of 20-m radius that will be used as controls for vegetation measurements. These unburned areas are estimated to comprise 1.0% ~f the total treatment area. �131 B. If the proposed action is not selected, removal of vegetation structure can be accomplished by brush beating and raking the proposed unit. This is expected to increase the cost of treatment, however, and the effects of fire, as a management tool, on sage grouse populations will continue to remain undocumented. Nutrient release associated with burning cannot be expected via this alternative. III. Affected Environment/Environmental Consequences A. Proposed Action Vegetation in the area of the proposed action consists of an overstory of mountain big sagebrush, with an understory of perennial grasses and annual and perennial forbs. Approximately 92 acres of this vegetation will be altered as a result of the action. It is expected that 99% of the sagebrush within the burn units will be killed, and will take many years to regenerate. The grass and forb community will be depleted temporarily, but within 2 years following the burn should respond to the release of competition with sagebrush by improving to a higher level of production and vigor than that found prior to the burn. The proposed project area provides habitat for a variety of wildlife dependent on the sagebrush ecosystem. The more important species in the area include sage grouse, pronghorn, ~ule deer and raptors. Several species of small birds and mammals also use the area. The proposed burn will eliminate sagebrush habitat until new sagebrush re-establishes. Feeding and loafing habitat for sage grouse will be eliminated until sagebrush is re-established. Understory vegetation in the burn units is expected to flourish and should provide highly nutritious spring forage for mule deer, elk, and pronghorn. The increase in understory should also provid~ livestock forage away from the riparian zone associated with Deer Creek. Soils in the treatment area are of the Cabin sandy loam series with medium runoff. The risk of water erosion is moderate and the hazard of wind erosion is severe. A map delineating the soils of concern is in Appendix II. Air quality in this area is excellent. During the burning process, quality will be affected adversely. This subject will be covered in greater detail in the Deer Creek Burn Plan, which will be prepared prior to burning and coordinated with all concerned agencies. Immediately after the burn, infiltration decreases due to the water repellency of burnt organic matter. When precipitation occurs on wet soil, infiltration reductions cause high runoff and a doubling in sediment loads. As grasses come in, infiltration will recover and runoff will be reduced. As most runoff occurs during spring melt, before grasses are established, the first year will see increases in sediment, phosphorous and possibly potassium. If �:' 132 grass cover occurs, the area will re-stabilize. (The intensity of the burn will greatly determine the extent of impact to soil and water). BLM public lands identified in the proposed action are within the North Park Extensive Recreation Management Area (RMA). The existing physical and social setting for recreational use are those described for a Roaded Natural Opportunity Class as defined in BLM Manual 8320. This area is characterized by a predominantly natural environment with moderate sights and sounds of man. Resource modification consists primarily of numerous access roads and trails, and range developments to benefit grazing. Springs, reservoirs, fences, and vegetative manipulation (a burn area to the east) are noticeable throughout the surounding area. These developments generally harmonize with the natural environment and indirectly benefit recreation resources by dispersing grazing activity and by protecting riparian habitat and water resources. The predomiant recreational activity is hunting for pronghorn, mule deer, and sage grouse. Associated with hunting is the use of Off Road Vehicles (ORV's) and camping. Use is moderate during these hunting seasons and indicental throughout the remainder of the year, with exception of years of heavy snow accumulation suited for use of snow machines. Concentration of tourists and sightseers may be high on the neighboring Colorado State Highway 125 during the winter ski season and summer vacation season. Travel on Jackson County Road 27 to the east may be moderate to high during the summer. The proposed action may create short-term impacts to recreation resources, but after establishment of perennial grasses and an overall vegetative cover, opportunities for hunting will be improved. By improving rangeland, dispersing grazing activity and enhancing wildlife habitat, the recreational setting and experience in a Roaded Natural Environment will be of a higher quality than before the burn. During the burn and in the time it takes to establish ground cover, scenic qualities will be significantly impacted and recreational opportunities, especially for hunting and sightseeing will be lost. The temporary loss of of public lands for recreational use during this period will not significantly affect opportunities provided on the majority of public lands in the North Park Extensive RMA. Public lands in T 7N, R 78W, Sections 30, 31, and 32, have been inventoried and classified as Visual Resource Management (VRM) Class IV. Resource modification in a VRM Class IV may create contrasts that attract attention and are a dominant feature of the landscape in terms of scale. Changes should repeat the basic elements of line, form, color, and texture inherent in the landscape. The entire area encompassed by the unit described in the proposed action consists of a flat sagebrush bench. VRM Class IV areas are of "moderate" sensitivity since these areas are seldom seen from major transportation condors. The entire area is at the low end of the Bcale for scenic quality. �133 Short-term impacts from the proposed action will be most signficiant in terms of visual resources. During and immediately following the burn, the landscape will shift to VRM Class V. This is an interim classification for landscapes in need of rehabilitation or where management practices have reduced landscape quality. The burn will create obvious contrasts in line, color, form, and texture. However, upon regrowth of vegetation and establishment of native grasses, the visual quality of the landscape will shift back to VRM Class IV approaching Class III. In the long term, visual resources could significantly benefit from the proposed action. The removal of overstory big sagebrush and regrowth of lush native grasses will change a rangeland landscape to a pastoral landscape which may be construed as more scenic compared to the surrounding sagebrush covered. In turn, diversity in vegetation contributes to visual quality. A Class III inventory has not been performed in the proposed burn area, however, there is an unsubstantiated report of a cultural site (AR 134) somewhere within the NE 1/4 NW 1/4 of Section 32, T 7N, R 78W. Prior to burning, a control test plot should be established in an area where cultural resources occur, so that the effects of burning can be evaluated on open lithic sites. Following the burn, the control test plot should be re-examined to assess the effects of the fire on lithic sites. Additionally, no burning should be planned in the vicinity of historic structures. Firelines should be given Class III inventory prior to construction due to surface disturbance caused by raking the brush into piles. B. No Action If the proposed action is not selected, brush beating will temporarily eliminate sagebrush habitat. Sage grouse feeding and loafing sites are expected to be eliminated until re-establishment of sagebrush. Understory vegetation is expected to flourish and should provide adequate spring forage for mule deer, elk, and pronghorn •. It should also benefit livestock provided the unit is kept free from livestock grazing for a minimum of 2 growing seasons. This alternative action will create slightly lesser impacts to recreation resources than treatment by fire, but the same consideration (i.e., resource inventory) should occur. The impacts from the increasing use of fire as a management tool, to sage grouse populations will remain undocumented. C. Critical Elements The following critical elements apply to both Alternatives A and B: 1. Wilderness - the area of the proposed action does not lie within existing wilderness or study areas. �134 2. ACEC - the area of the proposed action does not lie within an Area of Critical Environmental Concern. 3. Cultural Resources - see III.A. 4. Visual Resources - see III.A. 5. Threatened/Endangered Species - none is known to be in the area of the proposed action. 6. Prime or Unique Farmland - the area of the proposed action does not lie on this type of land. 7. Air/Water Quality - see III.A. 8. Flood Plains/Flood Hazard - the area of the proposed action does not lie in these areas. 9. Socio-Economic Impacts - no impacts. 10. IV. The proposed project is in conformance with the Kremmling Resource Management Plan. Mitigating Measures A. Proposed Action 1. The unburned buffer strip surrounding the unit should be at least 190 feet wide. 2. If sufficient natural seeding does not occur within a reasonable time period, artificial seeding should be done. 3. Rilling is not expected to occur. If excessive rilling occurs, watershed rehabilitation work will be considered. 4. Water sediment loads will be monitored by a hydrologist after the second year of the burn to assure stabilization is returning. 5. Following completion of the burn, re-evaluation of impacts to visual resources will be done. If it is determined that the burned area is highly visible to the user public, interpretive signs may be erected at suitable locations explaining the purpose and results of the action. 6. A Class III (100% pedestrian) cultural resource inventory shall be completed prior to construction by a qualified professional archaeologist along all constructed firelines. A report of the inventory will be submitted and approved by the BLM with stipulations as appropriate in order to comply with EO 11593 and Section 106 of the National Historic Preservation Act of 1966. �135 7. B. If, in its operation, the cnaw discovers any cultural remains, monuments or sites, or any object of antiquity subject to the Antiquity Act of June 8, 1906 (34 Stat. 225; 16 U.S.C. secs. 431-433), the Archaeological Resource Protection Act of 1979 (Public Law 96-95), and 43 CFR, Part 3, they shall immediately cease activity and report directly to the BLM Area Manager. The Bureau shall then take such action as required under the Acts and regulations thereunder. Brushbeating The above measures 5-7 apply. �136 c- •.•• ..~ R .75 'II. .:;:.~ 25 f L~~- I ....::. -'. " '" ~. 8438+ " c, \\ ~ ~ _ " ··~·8.•.• 1 'v"'" ,~' ,\ ) . , 'I " \\ \\ \\ \\ . ,/ 36 T. 70.1. " " II ", 1/ 1/ " '--" T G N. 1/ \, II '- , \ "" " " " ..,. •..'" •... Appendix I - Location of the Deer Creek Wildlife Burn, North Park, Jackson County, Colorado, Fall 1987. (From USGS 7.5' series, Owl Ridge Quadrangle Jackson County, Colorado, 1955). �137 , . 1 -\ \~\~ <, f Ca 25 Ca C Ca GeD C. Appendix II - Soils map of the proposed Deer Creek Wildlife Burn, North Park, Jackson County, Colorado, Fall 1987. �.; 138 SOIL SURVEY TABLE Map symbol Ab Ag B4 Bg BI< Bn Bo B. Bw Bx By C" Cd Cf CoD CoF Cr C. Ct CyF Do Du Eo EhE Fe Fh Fo GeD GkE Gn GoE I.-Acreage and proportionate extent of the soils Soil name Acres Aaberg-Barishrnan association _ Agneston gravelly coarse sandy loam, 5 to 40 percent slopes _ Badland _ Bangston fine sand, 1 to 10 percent slopes _ Blackwell loam _ Blevinton sandy loam, 8 to 20 percent slopes _ Boettcher-Bundyman association Bosler sandy loam _ Bowen gravelly sandy loam, 15 to 45 percent slopes _ Brinkert-Morset association _ Buffmeyer sandy loam, 4 to 18 percent slopes _ Cabin sandy loam _ Chedsey loam, 5 to 12 percent slopes _ Coalmont-Fluetsch complex _ Cowdrey loam, 4 to 10 percent slopes _ Cowdrey loam, 10 to 50 percent slopes _ Crespin-Carlstrom clays _ Crespin-Carlstrom stony clays _ Cryaquents _ Cryorthents, steep _ Dobrow loam _ Dune land _ Eachuston gravelly loam _ Ethelman sandy loam, 0 to 25 percent slopes _ Fleer loam _ Fluetsch- Tiagos association -----Forelle loam _ Gelkie sandy loam. 2 to 15 percent slopes _ Gelkie sandy loam. moderately deep variant, 0 to 25 percent slopes _ Girardot silty clay loam --------Gothic slopes loam, 0 to 20 percent _ Grafen-Rock outcrop complex ---Grimstone-Siebert association ---Handran extremely stony sandy loam, 20 to 40 percent slopes --Kather clay loam, 5 to 20 percent slopes _ Larand fine sandy loam, 3 to 25 percent slopes _ Larand fine sandy loam, 25 to 40 percent slopes _ 4,981 Percent II 0.7 Map symbol Le LuE 5,084 1,340 0.7 0.2 17,658 12,505 2.5 1.8 LyD Me MbF 10.821 5,703 22,880 1.5 0.8 3.2 Me 3,985 3,848 0.6 0.5 MrO MsO Mn Mo 2,577 23,326 0.4,1 MuE 3.3 NeE 1 2,817 16,661 2.31 NeF 10,924 1.51 Nr 6.012 8.348 1.889 23.567 39.198 9,585 1.202 4,775 1.340 3.608 94.226 11,234 0.4 I 10e 0.81 On 1.1 I P~F 0.31 3.3 PeE 5.51 1.3 I PeF 0.2 ! 0.71 Ph I Pr 0.2 Ra i 0.511 13.2 I 1.6 !I RhO Rk ,I Ro 14,360 962 7,661 2.0 I! RtE :j '0 0.1 :: Sr 1.1 ;1 SuE 7.970 9.275 9,482 1.1:iTe 1.3 :, Tn 1.3 ,i TeF 1,718 0.2 .! ~ITv !Wa 12,264 1.7:1 We 10,100 1.4i 2,508 !I YeF 0,4 :1 ;1 :i ! Appendix II (continued) - Explanation of symbols. _~_cres Soil name Leavitt loam Lulude cobbly loam, 10 to 25 percent slopes Lymanson cobbly loam, 4 to 10 percent slopes MacFarlane-Rock outcrop association Manburn gravelly coarse sandy loam, 10 to 40 percent slopes Mendenhall loam Mine pits and dumps :'Iirror-Rock outcrop complex Mord loam, 4 to 15 percent slopes Mcrset loam. 1 to 15 percent slopes Mugging slopes loam, 5 to 30 percent Nokhu loam. 0 to 25 percent slopes Nokhu loam, 25 to 50 percent slopes Norriston ~a •.•. elly sandy loam Owen Creek sandy loam Owen Creek-Norriston association Parkview very stony loam, 20 to 35 percent slopes Peeler sandy loam. 5 to 25 percent slopes Peeler sandy loam, 25 to 40 percent slopes Perceron-Hyannis association Pinkham-Rock outcrop associat.ion Randman sandy loam Rawah loam. 3 to 10 percent slopes Rock land _ 9,482 _ 4,741 _ 1,992 _ :"2,608 _ ., _ _ _ 1,992 3,348 800 7,386 5,394 _ 7,489 _ _ _ _ _ 2,061 1,615 4.947 4.500 _ 5,565 _ 2,-173 _ ~ 4,016 ; _ -. ~.501 ~ 3.S95 : 5.654 _ _ -:,092 ~.806 Rock outcrop ~------------Rouert g ravef ly sandy loam. 10 to 25 percent slopes _ Spicerton sandy loam _ Stumpp clay loam _ Sudduth loam, 5 to 15 percent slopes _ Tealson-Rock land association _ Tine sandy loam _ Troutville sandy loam. 15 to 45 percent slopes _ Troutville-Newcomb association __ 'Vaiden sandy loam _ Wichup loam _ Yochum gra velly sandy loam 35 to 65 percent slopes ..: _ ~ater _ Total-"!.. 859 _ _ s.sn ',417 .; :~.040 :,092 ::_':.711 : -.486 ~.943 '.057 ::.520 ~.516 :.905 :.928 : .1i9 7:'':.640 F ,::- �139 JOB PROGRESS REPORT State of: Colorado W-152-R Project: Avian Research 5 Job --- Work Plan: 8 Job Title: Population Inventory and Habitat Use by Lesser Prairie-chickens' in Southeast Colorado Period Covered: Author: 01 January through 31 December 1987 Kenneth M. Giesen Personnel: Clait Braun, Beth Dillon, Ken Giesen, Rick Hoffman, Gwen Kittel, Jennie Slater, Chuck Wagner, Bryant Will, Colorado Division of Wildlife ABSTRACT Lek surveys were conducted on a 4l.4-km2 study area and surrounding area of the Comanche National Grasslands. Both lek numbers and total numbers of lesser prairie-chickens (Tympanuchus pallidicinctus) counted increased from previous years. Analysis of the lek count data from the study area indicates a strong correlation between male breeding density and number of active leks (r = 0.91) but no relationship between male breeding density and average lek size (r = -0.014). Experimental roadside transect routes to measure observer efficiency in detecting active leks indicated 20.0-66.7% of known leks were missed under favorable weather conditions. Timing of transects and observer differences were found to affect the results. Experimental quadrat surveys resulted in 0.0-100% of active leks being located on individual quadrats with a higher proportion of leks (86.7%) being located during the peak of hen attendance than 2 weeks later (46.7%). A total of 27 prairie-chickens were captured and banded with 10 hens and 9 males being fitted with radio transmitters. Average home range documented was 347 ha. Hens dispersed 0.4 to 2.9 km from leks for nesting. Average clutch size was 10.8 eggs. Eightly random vegetation transects were measured to document residual vegetative structure and species composition. ��141 POPULATION INVENTORY AND HABITAT USE BY LESSER PRAIRIE-CHICKENS IN SOUTHEAST COLORADO Kenneth M. Giesen Both distribution and populations of lesser prairie-chickens in North America have decreased >90% from historic levels of the 1800's (Taylor and Guthery 1980). Although the exact historic distribution of lesser prairie-chickens is unknown, early reports (Bendire 1892, Judd 1905, Bent 1932, Baker 1953, Sands 1978) suggested they were abundant and widely distributed throughout their range. Although Aldrich (1963) indicated lesser prairie-chickens historically inhabited about 360,000 km2 in 5 states, recent e~timates suggest a current population of 50,000 birds existing on 125,000 km (Crawford 1980, Taylor and Guthery 1980, Johnsgard 1983). Although evidence suggests lesser prairie-chickens were historically peripheral in Colorado, they were thought to be common to abundant in 6 southeastern counties (Baca, Prowers, Bent, Kiowa, Lincoln, and Cheyenne), and peripheral in adjacent counties (Loeffler 1983). Recent surveys have documented breeding populations in Baca, Prowers, and Kiowa counties (Hoffman 1963, Loeffler 1983, Rash 1985). The lesser prairie-chicken is currently classified as a threatened species in Colorado. P. N. OBJECTIVES The objectives of this study are to evaluate 1ek surveys as indices to population trends, ascertain the accuracy of aerial and ground surveys in detecting leks, describe the seasonal floristic and structural characteristics of lesser prairie-chicken habitats in southeast Colorado, and contribute to preparation of a recovery plan for lesser prairie-chickens in Colorado. Segment Objectives 1. Review pertinent literature applicable to the objectives of this study. 2a. Locate all active leks within the 41.4 km2 primary study area and obtain at least 1 count/week (Mar-May) of all males and females on each lek. 2b. Survey all historic leks in Baca County and obtain at least 1 count of males on each active 1ek. 3. Select 4 20-km long roadside listening transects within the range of lesser prairie-chickens in Baca County and test the ability of naive observers to detect active lesser prairie-chicken leks within 1.6 km of the transects. 4. Select 2 or more quadrats, 40-50 km2 each, within the range of lesser prairie-chckens in Baca County, and test the ability of a naive observer to detect active lesser prairie-chicken leks from low-level aircraft flights. �\ 142 5. Trap and band lesser prairie-chickens on active leks within the primary study area. Up to 20 will be marked with miniature radio transmitters to facilitate their periodic location. 6. Locate lesser prairie-chicken nests by following radio-marked hens. Record clutch size, incubation period, and nest fate. 7. Locate radio-marked birds weekly for estimates of movement and home range. 8. Measure vegetative cover at grouse use and random sites. Height and canopy cover of shrubs, forbs, and grasses will be recorded. 9. Compile data, analyze results, and prepare annual progress report. METHODS Field surveys were conducted on the Comanche National Grasslands and adjacent areas in eastern Baca County from March through June using binoculars, a parabolic micrphone listening device, and a trained pointing dog to locate active lesser prairie-chicken leks. All leks known to be active in 1986 were surveyed as well as most known historic lek sites. Active leks were visited within 2 hours of sunrise to count grouse and classify them to sex. Four roadside transects were conducted by naive observers during the peak of lesser prairie-chicken breeding (14-15 Apr) and 2 weeks later. A 3-minute listening stop was taken approximately every 800 m to listen for displaying grouse. Distance and direction to detected leks were estimated and plotted on a map. Routes began 15 minutes prior to sunrise and were completed within 2 hours. Aerial quadrat searches for leks occurred during the peak of breeding activities (14-16 Apr) and 2 weeks later. Three quadrats, each approximately 40 to 48 km2 were plotted on topographic maps and boundaries flagged on the ground. A jet Bell Ranger helicoptor with a pilot and 1 observer/recorder flew north-south transects 400 m apart at approximately 50 m altitude. Grouse sightings were recorded on a portable cassette recorder and later plotted on a topographic map. Visual landmarks including topographic features, fencelines, windmills, and roads were recorded and used to verify lek locations. Because grouse were not detected unless flushed, a lek was defined as 2 or more grouse flushing from 1 site. Cannon-nets and funnel traps (Giesen et ale 1982) were used to capture grouse on leks. Each captured grouse was marked with a numbered aluminum band and a unique combination of colored plastic bandettes. Miniature solar- or battery-powered transmitters (weight 18-24 gms) were attached to all captured females and selected males using a poncho (Amstrup 1980). Radio-marked birds were located using a portable receiver and hand-held yagi antenna. Birds were approached on foot until they flushed. Vegetative structure and species composition were measured using line-intercept of canopy cover (Canfield 1941) and a range pole (Robel et ale 1970). Sand sage (Artemisia filifolia) density was measured on 0.001 ha circular plots. The minimum convex polygon method (Mohr 1947) was used to calculate home ranged. �143 RESULTS AND DISCUSSION Lek Surveys A total of 155 counts of 30 active leks was obtained in Baca County between 7 February and 21 May 1987 (Table 1). In addition, 11 historic lek sites were surveyed and found to be inactive. A minimum of 219 males, 22 females, and 281 total birds was counted for an average count of 9.4 birds/active lek. Summaries of lek count data since 1977 indicate the dynamic nature of lek sites with many becoming inactive and others becoming active (Table 2). Although there is an upward trend in numbers of males counted and numbers of leks active, the data should not be used to calculate absolute breeding population size because not all active leks are located and counted each year. Because numbers of grouse attending leks fluctuates during the breeding season and survey timing and intensity varied each year, the data (Tables 1 and 2) do not reflect actual variability. Analysis of lek surveys and lek count data on the 41.4-km2 study area (Table 3) indicates a strong positive correlation between male breeding density and number of active leks (r = 0.91) but not between male breeding density and average lek size (r = -0.014). If we assume the high count of males on leks is a constant proportion of the total population, then lek density is a better index to population changes than average lek size. These data support results of prairie grouse population surveys in other states (Cannon and Knopf 1981, Martin and Knopf 1981). Lek Transect Routes Results of experimental roadside transect routes (Table 4) indicated 20.0-66.7% of known active leks within 1.6 km were missed under good weather conditions (winds <10 km/hr, clear-partly cloudy skies, no precipitation). When winds exceeded 30 km/hr on 14 April, only 9.1% and 14.3% of active leks were detected on 2 transects. A higher proportion of leks was detected during the peak of hen attendance than 2 weeks later (62.5% vs. 53.8%) under similar weather conditions. Observer differences also occurred with 1 observer detecting 63.2% of the known leks and the 2nd observer detecting 46.7% of the leks under similar conditions. Although many state wildlife agencies use survey routes to monitor changes in numbers of prairie grouse the technique has not been evaluated for accuracy or preC1S10n. Weather conditions, observer efficiency, and timing of counts all appeared to influence results in Colorado in 1987. Other factors including lek size and topography might also be important but were not investigated. Additional testing should be conducted to document factors influencing lek detection before survey routes are implemented as a management strategy to monitor population trends. �144 Table l. Lesser Prairie-chicken lek count data, Baca County, 1987.a N Lek counts 2 3 4 5 6 7 12 14 17 18 25 28 31 33 35 36 37 38 39 40 42 44 86-1 86-2 86-3 87-1 87-2 87-3 87-4 87-5 10 6 6 20 Total Average 8 6 2 5 4 11 3 22 1 5 1 2 2 7 1 6 1 1 8 4 4 3 1 2 2 1 155 Count period 7 20 20 7 21 21 3 31 6 21 23 20 21 6 18 31 27 19 19 19 27 1 1 Feb-29 Mar-17 Mar-17 Feb- 9 Mar-17 Mar-17 Apr-21 Nar-16 Apr-23 Mar-24 Apr-21 Mar-II 18 Apr Mar- 9 18 Apr Apr-21 Apr-27 Mar-16 9 May Mar-16 18 Apr 16 May Mar- 7 Mar- 7 Mar- 5 Mar- 1 15 Apr May- 8 May- 8 13 May Apr May May May May May Apr Hay Apr Apr May May Apr May Apr May May May Apr Apr May May May Males 9 3 3 18 3 8 4 8 7 13 6 17 9 8 18 0 18 7 0 9 10 5 11 5 8 0 0 0 7 5 219 7.3 High count Females Totalsb 1 0 0 4 0 0 2 0 2 2 0 8 0 0 1 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 10 6 6 19 5 8 5 9 9 15 6 24 12 9 21 2 18 7 6 9 10 8 14 6 8 4 7 4 9 5 22 0.7 281 9.4 aLeks 8, 10, 13, 21, 23, 26, 27, 29, 32, 41 and 46 were surveyed with no birds 0 bserved. blnc1udes males, females, and birds not classified to sex. �145 Table 2. Lek 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 86-1 86-2 86-3 87-1 87-2 87-3 87-4 87-5 High counts of male ,lesserprairie-chickens,Baca County, 1977-87. 1977 4 18 8 9 24 22 15 1 0 0 7 0 7 17 17 16 2 3 3 5 __b 1978 1979 1980 1981 5 14 6 8 NC 15 11 NC NC NC NC 5 13 11 11 0 4 14 NC 0 4 13 16 6 NCa 10 2 7 12 15 11 0 0 0 NC 7 12 10 12 NC 3 NC NC 2 1 6 17 NC 0 1 17 12 15 14 11 0 0 0 0 17 8 9 9 0 0 9 0 0 0 4 19 0 3 9 7 7 0 6 15 7 16 14 6 0 0 0 0 20 8 8 0 0 0 9 0 0 0 3 30 0 6 4 4 7 4 18 14 6 8 6 aNo count. bLek not yet located. Year 1982 0 3 12 7 29 19 9 0 0 0 0 14 7 6 0 0 0 10 0 0 0 0 33 0 11 2 4 4 0 10 17 0 6 0 10 12 1983 1984 1985 1986 1987 0 12 11 9 26 14 8 0 0 0 0 16 5 12 0 0 0 9 0 0 0 0 23 0 3 2 3 4 0 0 13 0 0 0 16 7 12 7 10 4 0 9 7 7 23 17 7 0 0 0 0 18 0 11 0 0 2 5 0 0 0 0 21 0 2 3 0 0 0 6 11 0 0 0 21 0 10 8 18 5 3 14 0 7 7 0 18 6 5 0 0 0 0 0 0 11 0 0 5 9 0 0 0 0 16 0 0 0 4 10 2 2 7 5 0 0 13 0 12 3 9 7 7 7 7 3 4 4 NC 16 2 0 17 6 9 NC NC NC NC 5 0 10 NC NC 4 10 NC NC 0 NC 2 NC 2 0 0 12 0 0 2 0 0 0 10 0 12 2 11 8 3 0 5 0 0 1 15 6 7 NC 9 3 3 18 3 8 0 NC 0 NC 4 0 8 NC NC 7 13 NC NC 0 NC 0 NC 6 0 0 17 0 NC 9 0 8 NC 18 0 18 7 0 9 0 10 NC 5 NC 0 11 5 8 0 0 0 7 5 �146 Table 3. Lek count trends of lesser prairie-chickens on a 4l.4-km2 (16 2 mi ) study area, Baca County, Colorado, 1980-87. Year N leks N males 1980 1981 1982 1983 1984 1985 1986 1987 6 6 6 6 4 5 7 8 59 55 59 65 46 46 75 74 x Breeding density (males/km2) males/lek 9.8 9.2 9.8 10.8 11.5 9.2 10.7 9.2 1.42 1.33 1.42 1.57 1.11 1.11 1.81 1.79 Table 4. Leks detected during experimental roadside transects in Baca County, Colorado, 1987. Transect Length (km) 17.6 22.5 19.2 19.2 1 2 3 4 N leksa N detected 6 Survey 1 Survey 2r: 3 7 11 5 2 ld ld 3 1 3 6 4 aNumber of active leks within 1.6 km of transects. b14-l5 Apr. c30 Apr-l May. dWinds >30 km/hr. Aerial Surveys Aerial quadrat surveys were relatively effective in detecting active lesser prairie-chicken leks during the peak of mating activities but less effective 2 weeks later (86.7 vs. 46.7% of active leks detected, Table 5). Because the aircraft, pilot, observer, and procedures were identical for both survey periods, the causes of the discrepancy are unknown. Possibly hens are more likely than males to flush in response to low level aircraft flights. During experimental flights over 2 leks the observer failed to detect male lesser prairie-chckens on leks until the birds flushed despite knowing the approximate lek locations. Additional tests of factors affecting detection of lekking grouse from aircraft should be conducted to ascertain the relative importance of aircraft type (helicoptor or fixed-wing), altitude, flight speed, and presence or absence of hens on leks. The advantage of aerial �147 surveys of leks over ground surveys is the relative ease in which large parcels of rangeland can be surveyed to detect occupancy by lesser prairie-chickens. However, unless the survey is conducted during the peak of mating when hens are attending leks, the survey may underestimate lek density and relative population size. Table 5. Leks detected by experimental aerial surveys of lesser prairie-chicken occupied rangelands in Baca County, Colorado, 1987. Quadrat Quadrat size (km2) N leksa 1 2 3 47.9 46.0 40.1 3 3 9 N leks detected Flight 2c Flight 15 3 3 7 3 0 4 aNumber of active leks within quadrat boundaries. b14-l6 Apr. c28-30 Apr. Trapping and Banding A total of 27 lesser prairie-chickens (18 males, 9 females) was trapped on 5 of 8 active leks within the primary study area. All but 5 males were captured in funnel traps on leks. The remaining 5 males were captured using a cannon-net. Males quickly habituated to the presence of funnel traps and the chicken-wire drift fences and became difficult to capture. Few females were captured because they hesitated to enter the funnel opening after following the wire leads, perhaps because the funnels were too long and narrow. However, several hens escaped from traps when funnels were shortened. Apparently the small size of the traps «1.0 m diameter) allowed them to find the funnel opening and escape. All captured prairie-chickens were marked with a unique combination of colored bands to facilitate future identification. Ten males and all 9 hens were fitted with miniature radio transmitters to facilitate their periodic relocation. Although the transmitters were not thought to have a major affect on daily activity patterns or movement of birds, there is a possibility that radio-marked birds had higher than typical mortality from predation. This increased predation on radio-marked birds has been previously reported (Herzog 1979, Warner and Etter 1983, Hines and Zwickel 1985, Marks and Marks 1987). Most males captured (14 of 18, 77.8%) were 2 years of age or older suggesting that many yearling males may not regularly attend leks or that trapping methods were selective for more dominant and older males. There appeared to be no age bias for females captured (5 adults, 4 yearlings) although older hens were captured earlier in the season than yearlings. �148 Nesting The fates of 9 radio-marked hens were ascertained using radio-telemetry techniques. Four hens were killed by raptors prior to nest completion, 1 hen was not relocated after trapping, and 4 hens completed clutches. Two of these hens lost clutches prior to hatching and 2 hens successfully hatched their clutches. Average clutch size was 10.8 eggs (range 9-13) and average distance from ~ek of capture to nest site was 1.9 km (range 0.4-2.9 km). Home Range Home ranges were measured for 5 males and 5 females for which data were available (Table 6). Home range size varied among individuals (range 44-662 ha) but there was no significant difference between males and females (t = 17, p > 0.2) • Combined average home range size was 347 ha , Home range size of radio-marked lesser prairie-chickens in Baca Table 6. County, Colorado, 1987. Band Age Sex 335 340 2+ I- M F 343 344 345 349 351 354 355 356 I2+ 2+ 2+ 2+ 2+ 2+ 2+ F F F F M M M M Time interval Home range (ha) 3 Apr-14 Oct 6 Apr- 1 Sep 14 15 15 15 17 29 29 8 Apr-IO Apr-14 Apr-23 Apr-13 Apr- 1 Apr-13 Apr-14 May-14 236 181 May Oct Jun Oct Sep Aug Oct Oct 315 329· 459 226 468 44 662 550 Habitat Measurement A total of 80 random vegetation 1987 to complete the vegetative Analysis has not been completed sandsage density and height and complete analysis of vegetation final report. transects was measured sampling of the entire although there appears species composition of on the study area will on the study area in area begun in 1986. to be high variation in residual grasses. The be provided in the LITERATURE CITED Aldrich, J. W. 1963. Geographic orientation of American Tetraonidae. Wildl. Manage. 27:529-545. Amstrup, S. C. 214-217. 1980. A radio-collar for game birds. J. J. Wildl. Manage. 44: �149 Baker, M. F. 1953. Prairie chickens of Kansas. Misc. Publ. 5. 68pp. Univ. Kansas Mus. Nat. Hist. Bendire, C. E. 1892. Life histories of North American birds with special reference to their breeding habits and eggs. u.s. Natl. Mus. Spec. Bull. 1. 446pp. Bent, A. C. 1932. Life histories of North American gallinaceous birds. Natl. Mus. Bull. 162. 490pp. U.S. Canfield, R. H. 1941. Application of the line intercept method in sampling range vegetation. J. For. 39:388-394. Cannon, R. W., and F. L. Knopf. 1981. Lek numbers as a trend index to prairie grouse populations. J. Wildl. Manage. 45:776-778. Crawford, J. A. 1980. Status, problems, and research needs of the lesser prairie chicken. Pages 1-7 in P. A. Vohs and F. L. Knopf, eds. Proc. Prairie Grouse Symp. Oklahoma State Univ., Stillwater. Giesen, K. M., T. J. Schoenberg, and C. E. Braun. 1982. Methods for trapping sage grouse in Colorado. Wild1. Soc. Bull. 10:224-231. Herzog, P. W. 1979. Effects of radio-marking on behavior, movements, and survival of spruce grouse. J. Wildl. Manage. 43:316-323. Hines, J. E., and F. C. Zwicker. 1985. Influence of radio packages on young blue grouse. J. Wildl. Manage. 49:1050-1054. Hoffman, D. M. 1963. The lesser prairie chicken in Colorado. Manage. 27:726-732. Johnsgard, P. A. 1983. Lincoln. 4l3pp. The grouse of the world. J. Wildl. Univ. Nebraska Press, Judd, S. D. 1905. The grouse and wild turkeys of the United States and their economic values. U.S. Dep. Agric. BioI. Surv. Bull. 24. 55pp. Loeffler, C. 1983. The status and management of the lesser prairie chicken in Colorado. Unpubl. Rep., Colorado Div. Wi1dl., Colorado Springs. 9pp. Marks, J. S., and V. S. Marks. 1987. Influence of radio-collars on survival of sharp-tailed grouse. J. Wildl. Manage. 51:468-471. Martin, S. A., and F. L. Knopf. 1981. Aerial survey of greater prairie chicken leks. Wildl. Soc. Bull. 9:219-221. Mohr, C. o. 1947. Table of equivalent populations of North American small mammals. Am. MidI. Nat. 37:223-249. Rash, M. T. 1985. Survey of the lesser prairie-chicken in Colorado, 3 April25 May 1985. Unpubl. Rep., Colorado Div. Wildl., Colorado Springs. 22pp. �150 Robel, R. J., J. N. Briggs, J. J. Cebula, A. D. Dayton, and L. C. Hulbert. 1970. Relationships between visual obstruction measurements and weight of grassland vegetation. J. Range. Manage. 23:295-297. Sands, J. L. 1978. Game bird studies. Performance Rep., Proj. W-l04-R-19. New Mexico Dep. Game and Fish Proj. Albuquerque. 5pp. Taylor, M. A., and F. S. Guthery. 1980. Fall-winter movements, ranges and habitat use of lesser prairie chickens. J. Wildl. Manage. 44:521-524. Warner, R. E., and S. L. Etter. 1983. Reproduction and survival of radiomarked hen ring-necked pheasants in Illinois. J. Wildl. Manage. 47:369-375. Prepared by ==--..::..~~.;=::;:...:....:IJ1~...::.~=~. ::.:....:.. Kenneth M. Giesen Wildlife Researcher _ � https://cpw.cvlcollections.org/files/original/a5a6010f9e0e65933a7886aebe48fbee.pdf 58f0d8a1d0b519137b279d5b701ef96e PDF Text Text 151 JOB PROGRESS REPORT State of Colorado - project W-152-R Work Plan _9_ Job Title: Author: Personnel: Job _8_ Food Selection During Winter Period Covered: Avian Research 01 January and Nutritional through Ecology 31 December of Blue Grouse 1987 T.E. Remington R.W. Hoffman, T.E. Remington, Division of Wildlife M.L. Stevens, Colorado ABSTRACT Digestibility of neutral detergent fiber (NDF) of Douglas-fir (Pseudotsuga menziesii)., lodgepole pine (Pinus contorta), subalpine fir (Abies lasiocarpa), and Engelmann spruce (Picea engelmannii) by 4 captive blue grouse (Dendragapus obscurus) averaged 13.5, 14.3, 17.3, and 7.5%, respectively. Tannin activity was high for needles of all species but was not related to blue grouse preferences among needle groups. Polyvinylpyrrolidone (which binds tannin) added to spruce needles at 2 and 5% of the Dm did not reduce nitrogen excretions or affect intake (~ > 0.05). Nitrogen in fecal droppings was excreted primarily as ammonium salts (33 to 55%) and uric acid (9 to 21%) or bound to plant fiber (9 to 25%). Uric acid excretion was inversely related to intake and weight loss (~ <0.05) across all species and represented normal endogenous nitrogen losses as well as loss due to catabolism of protein during energy . shortages. Ammonium salt excretion was positively correlated with intake (P < 0.05) on all conifer species and highest when grouse fed on unpalatable species (4.5 mg/g unpalatable vs. 2.6 mg/g palatable). Ammonium salts may be a byproduct of metabolic detoxification of plant defense compounds, arising through deamination of amino acids to furnish substrates (glucuronic acid, methyl or sulfur groups) for conjugation with toxins. Defense compounds in conifer needles represent a metabolic cost in nitrogen and energy to detoxify or restrict intake rather than directly decreasing digestibility as originally hypothesized. ��153 FOOD SELECTION AND NUTRITIONAL ECOLOGY OF BLUE GROUSE DURING WINTER Thomas E. Remington Chemical analyses of samples and statistical analysis and interpretation of data generated from previous trials with captive blue grouse were continued. Another trial was conducted which assessed the role which tannins may play in reducing the metabolizable nitrogen (MN) and energy content of Engelmann spruce needles. The primary effect of ingested tannins is to bind to and precipitate protein (McLeod 1974). It was hypothesized that the poor palatability and low MN content of Engelmann spruce needles is caused in whole or in part by tannins. This was tested by treating spruce needles with polyvinylpropylene (PVP) , a inert polymer which binds to tannins and inhibits formation of tannin-protein complexes (Gray 1978, Asquith and Butler 1985). Palatability and MN of spruce needles should increase, if the hypothesis is correct, when tannin activity is decreased. In addition, needles were collected and processed and four blue grouse captured for trials to be conducted in January of 1988. P.N. OBJECTIVES The objectives of this study are to investigate (1) winter food habits, and (2) winter food preferences of blue grouse, and (3) measure the nutritional quality (protein, cell contents) and anti-quality components (terpenoids, phenolic resins, neutral detergent fiber [NDF], acid detergent fiber [ADF]) of blue grouse winter foods and their relationship to diet preferences. Specific objectives are to: 1. Identify winter foods of blue grouse. 2. Investigate blue grouse winter use of conifers for food by species, tree ages, and growth forms in relation to their' availability. 3. Quantify tree species composition characteristics of blue grouse winter and physical feeding sites. 4. Measure protein and NDF, ADF content of conifer needles trees fed upon by blue grouse and from randomly-located trees. 5. Measure tannin, phenolic resin, and mono-, di-, and sesquiterpene levels in conifer needles from trees fed upon by blue grouse and from randomly-located trees. from �154 6. Rank blue grouse preference for Douglas-fir, subalpine fir, lodgepole pine, limber pine, and Engelmann spruce as winter foods. 7. Measure protein, NDF, ADF, and DM digestibility by blue grouse of randomly-selected needles of Douglas-fir, lodgepole pine, limber pine, subalpine fir, and Engelmann spruce. 8. Investigate the deterrent effects of specific phenolic resins, and mono-, di-, and sesquiterpenes to browsing by blue grouse and to blue grouse digestibility of conifer needles. SEGMENT OBJECTIVES 1. Complete chemical analyses (DM, nitrogen, fiber, gross energy, uric acid, urea, ammonia, tannins) of feed and excreta generated during trials in previous segments. 2. Code and enter resulting files. data onto existing computer data 3. Collect needles from Douglas-fir and/or lodgepole pine feeding and random trees to determine distribution of nutrients/anti-nutrients and for trials with captive birds. 4. Capture 4 blue grouse for use in feeding trials. 5. Conduct trials to evaluate ME and MN (or DMD and nitrogen balance) of feeding and random trees of Douglas-fir and/or lodgepole pine. 6. Analyze and interpret data and prepare progress report. Present pertinent findings at appropriate scientific meetings. DESCRIPTION OF STUDY AREAS This study was conducted on Whitely Peak and adjacent Burnt Mountain, located approximately 30 km west of Kremmling in Grand County, Colorado. Characteristics of these areas have been described by Cade (1985). METHODS Conifer needles and fecal and cecal excreta samples were prepared and neutral detergent fiber, nitrogen, gross energy, and dry matter content measured using standard and previously described techniques (Remington 1987). Uric acid (Remington 1987) and ammonia levels in fecal samples were measured, ammonia by microkjeldahl distillation without prior sample digestion. Tannin activity in needle samples was estimated by measuring the amount �155 of bovine serum albumin (BSA) precipitated by methanol of plant material (Asquith and Butler 1985). extracts Trial birds were captured with telescoping noose poles (Zwickel and Bendell 1967) and acclimated to experimental conditions and diets for 1 week prior to data collection. Trial methodology followed Remington (1987). Treatments consisted of 3 levels of PVP added to needles of Engelmann spruce; 0 (control), 2%, and 5% of DM. PVP was dissolved in ethanol (2% = O.952g/10 ml, 5% = 2.380g/10 ml) and sprayed over 100g (wet wt.) of needles. Control needles were sprayed with alcohol only. The needles of all groups were placed in a fume hood overnight to allow the alcohol to evaporate. Variables measured were dry matter intake (palatability), dry matter digestibility (DMD), and nitrogen balance (nitrogen intake - nitrogen excreted). NDF digestibilities calculated from the conifer species trial conducted in 1986 did not agree closely with the preliminary data reported (Remington 1987) from the aborted 1985 trial, probably because of the extreme physiological stresses imposed on the birds by the 1985 experimental protocol. Revised estimates and discussion of the 1986 results are presented. RESULTS AND DISCUSSION NDF digestibility ranged from 7.5 to 17.3% among species and averaged 13.1% for all species (Table 1). These values are substantially below the 38% digestibility of cellulose and 44% digestibility of lignin in heather by red grouse (Lagopus lagopus scoticus) estimated by Moss (1977). The methods used by Moss to estimate fiber are likely responsible for his inflated digestibilities, although it is possible that red grouse digest fiber far better than blue grouse. NDF digestibility is a function of how much NDF is made available to cellulolytic fermentation (i.e. that enters the ceca), and the efficiency of digestion of NDF within the ceca. These parameters were evaluated to assess causes of low NDF digestibility. NDF digestibility was determined largely by how much NDF entered the caeca since essentially all (avg. = 96.8; range across species = 94.3 to 98.6%) NDF that entered the ceca was digested (Table 1). Most fiber was excluded from the ceca. NDF digestibility of Engelmann spruce needles was about half that of the other 3 species, primarily because of greater exclusion of NDF from the ceca (Table 1). The low NDF digestibility of spruce needles is exacerbated by their relatively high NDF content. �156 Table 1. Digestibility of NDF in conifer needles by blue grouse. NDF Digestibility speciesb Psme pico Abla Pien %DM 0.395 0.474 0.383 0.416 Total 13.48 14.31 17.31 7.48 (%) Available In ceca Amount (g) 98.5 98.6 94.3 95.8 4.7 5.1 3.5 2.0 aassuming no fermentation outside of ceca. bPsme = Douglas-fir, pico = lodgepole pine, Abla fir, Pien = Engelmann spruce. to cecaa ~ of total 0 13.68 14.51 18.22 7.69 = subalpine Tannin activity (protein precipitating ability) of extracts of conifer needles was measured to assess their relationship to preference, palatability, and metabolizable nitrogen. Tannin activity did not vary substantially across needle groups (Table 2) and was not consistently related to preference or palatability. For instance, lodgepole pine, a palatable and preferred species, had a tannin index about 20% higher than the unpalatable and non-preferred subalpine fir. Tannin indices tended to increase with needle age in old and young trees of Douglas-fir, consistent with preferences of blue grouse for these groups and with their nitrogen losses on them. All groups had relatively high tannin index levels. On average there was enough precipitation capacity to bind twice as much protein as was actually present in the plant sample (assuming plant protein has an affinity for tannins equal to BSA). Given this it is not surprising that the small amount of variation across needle groups is unimportant. The protein precipitation assay exhaustively extracts tannins under conditions of optimal tannin solubility which may not reflect solubility in the stomach or gut of herbivores. Perhaps much of the precipitating capacity of tannins and/or other polyphenols is not realized because of poor tannin solubility in the gut. To test this I extracted plant samples with HzO-HCL (pH = 2.0) instead of methanol-HCL and repeated the assay. Protein precipitation declined by about half for most groups (Table 2). While this was a significant decrease, there remained enough precipitation capacity to bind all the protein in these needles. Obviously most of this invitro capacity is not realized in-vivo. How grouse circumvent this potential loss of protein is not obvious. Robbins et ale (1987) found that reduction of protein digestibility in conifer forage fed to elk (Cervus elaphus) was only 12% of that estimated by in-vitro protein precipitation. Chickens and rats are known to secrete a proline~rich protein from their salivary glands in �157 response to dietary tannins (Mehanso et ale 1983). These proteins have a tremendous affinity for tannins and may represent a countermeasure to prevent tannins from binding dietary protein or from attacking the gut wall. This strategy should still lead to elevated protein loss unless the inactivated tannin-proline protein complex can be metabolized farther down the digestive tract. Table 2. Absorbancea (590 nm) of dyed BSA precipitated by 375 or 500 ul of methanol-HCL or HzO-HCL extracts of conifer needles. Needle group Douglas-fir Lodgepole pine Subalpine fir Engelmann spruce Douglas-fir (young) 1-2 year old needles 3-4 year old needles 5-7 year old needles Douglas-fir (old) 1-2 year old needles 3-4 year old needles 5-7 year old needles aAbsorbance is linearly precipitated. !izO-HCL 500 ul Methanol-HCL 500 ul 375 ul 1.29 1. 36 1.12 1.26 0.98 1.11 0.84 1. 02 0.72 0.80 0.78 1. 30 1.48 1.54 1. 01 1. 33 1. 43 0.63 0.75 0.75 1. 33 1. 38 1.36 0.98 1.16 1.14 related to the amount of BSA If PVP had mitigated the protein precipitating activity of tannins in spruce needles as hypothesized, then nitrogen excretion should have decreased, nitrogen balance should have increased, and intake potentially could have increased with addition of PVP. Addition of PVP to needles of Engelmann spruce had no effect on their palatability (defined as dry matter consumption; £ = 0.97), or the nitrogen balance of birds feeding on them (£ > 0.05, Table 3). Cecal nitrogen excretion remained constant over treatment levels (£ = 0.19, Table 3) as well. If tannin-protein complexes are diverted into the ceca, then a beneficial effect of PVP in preventing formation of tanninprotein complexes should have been demonstrated by a reduction in cecal nitrogen excretion. Tannins do not appear to be the cause of excessive nitrogen losses when birds feed on Engelmann spruce needles. �158 Table 3. Nitrogen balance and cecal nitrogen excretion (mg) by 4 blue grouse following feeding of Engelmann spruce needles untreated and treated with 2 levels of PVP. Average of 3 replicates/bird. PVP Oa 2 5 422 Cecal Bal. -399 -310 -189 aTreatment 168 194 181 level Bird 426 Bal. Cecal -455 -457 -359 183 191 216 427 Bal. Cecal -467 -568 -473 201 242 242 428 Bal. Cecal -677 -795 -1008 192 219 235 (%DM) . Endogenous nitrogen losses have been measured both to correct apparent metabolizable energy and to investigate sources of nitrogen losses on poor foods. The principle nitrogen excretion product of blue grouse is ammonium salts, followed by indigestible plant protein (NDF nitrogen), and uric acid (Table 4). Consumption of Engelmann spruce and subalpine fir (unpalatable species) resulted in elevated uric acid (Fig. 1) and ammonia (Fig. 2) excretions compared to an equivalent amount of Douglas-fir or lodgepole pine (palatable species). Uric acid is the primary endogenous nitrogen excretion product in most birds (Farner and King 1972:541). Uric acid seems to be largely a byproduct of protein catabolism in blue grouse since the amount of excreted uric acid is an inverse function of intake and a direct function of weight loss (Fig. 1). Moss and Hanssen (1980) found this to be true of red grouse as well. Table 4. Forms of nitrogen excretion (% of total) in blue grouse fecal droppings following feeding on 4 conifer species. species Douglas-fir Lodgepole pine Subalpine fir Engelmann spruce NH3 salts 46.5 32.8 39.0 55.4 Bound 15.2 25.0 9.0 10.1 Uric acid 9.0 9.7 20.7 15.4 ~ 0 70.7 67.6 68.8 80.9 Ammonia nitrogen is positively correlated with intake but the form of this relationship differs among species (Fig. 3). Ammonium salts are normally a minor component (~ 15%) of endogenous nitrogen excretion in birds (Farner and King �159 BIRD #422 """ C) 6 6 140 BIRD #424 0 6 90 - 120 E •.....• 75 - o Z 100 0 0 0 0 « 60 ~ 80 0 0 a:: :;) 60 ~ 45 ~ 0 0 40 I I I 40 50 60 INTAKE 0 * 0 0 I I 50 80 60 70 """ C) E t- t- 200 I- 0 t- 150 t- 0 « 125 t- 0 a:: 100 r- 75 r- 50 r- 25 I- (g) 0 400 0 350 Z 0 100 450 0 175 90 BIRD #397 0 225 80 INTAKE (g) BIRD #425 250 * * 0 /::, 30 ~ * * 70 * 0 300 250 0 0 200 :;) 6 06 150 * 6 0 I 30 I 50' 40 INTAKE I I 60 70 (g) I- 100 ~ 50 0 /::, I- S* * /::, ** I 80 I 40 50 60 70 INTAKE 80 (g) Fig. 1. Uric acid nitrogen excretion as a function of intake for 4 blue grouse feeding on Douglas-fir (*), lodgepole pine (0), subalpine fir (0), and Engelmann spruce (6). * /::, 90 �160 BIRD #422 BIRD #424 375 240 f- 220 f... 350 •...•. C) E ...., * £:::,. 325 * * * 275 - 4: 200 Z ~ ~ c: 300 - Z 0 c. 0 180 0 6 4: 0 * 0 * 250 225 - 0 0 160 200 f- 0 175 0 140 _l 1 1 1 40 50 60 _l 70 80 0 ,I I 1 60 50 70 c; 1 80 1 90 100 INTAKE (g) INTAKE (g) BIRD #397 BIRD #425 6 350 375 6 325 •...•. 300 - 350 6 C) E 275 ...., Z 0 250 4: Z 0 225 ~ ~ 4: 325 6 f- 300 I- 275 * 0 200 0 0 175 * ** 0 0 250 f- 225 I- 200 f- ** 6 0 0 150 125 0 0 1 30 40 50 60 70 80 feeding on Douglas-fir Engelmann spruce (6). excretion 50 60 70 INTAKE (g) INTAKE (g) Fig. 2. Ammonia nitrogen 40 as a function of intake for 4 blue grouse (*), lodgepole pine (0), subalpine fir (D), and 80 90 �161 1972:541). The level of ammonia nitrogen found in fecal droppings of blue grouse following ingestion of conifer needles was excessive (33-55% of excreted nitrogen). Ammonia nitrogen excretion may not represent a true endogenous loss, but may result from detoxification of plant defense compounds. This Three predictions can be nitrogen loss will be designated as Nd• advanced and tested with available data. 1) Nd excretion should increase as dry matter consumption of a particular food increases. Conversely, if ammonia nitrogen represents a endogenous loss resulting from protein catabolism then it should decrease as intake increases. 2) Nd excretion per gram of dry matter intake should be higher on unpalatable foods (presumably with more toxins) than on palatable foods. 3) Toxins, such as monoterpenes or benzoic acid, should elevate Nd excretion. These 3 predictions were tested and found true (£ < 0.05). Nd excretion was positively correlated with intake of Douglas-fir (Figs. 3 and 4), subalpine fir, and Engelmann spruce (Fig. 3) with 84, 44, and 91%, respectively, of the variance in ammonia excretion explained by dry matter consumption. Nd excretion was not strongly correlated (£ = 0.12) with intake of lodgepole pine (Fig. 3) needles but was negatively correlated with weight loss (£ < 0.05, r2 = 0.48). The unpalatable species, subalpine fir and Engelmann spruce, had substantially higher Nd excretions per gram of intake than the palatable species, Douglas-fir and lodgepole pine (4.1 and 4.9 vs. 2.7 and 2.6 mg/g DM, respectively) . Ammonia excretions per gram intake did not vary across tree and needle age groups where palatability also did not differ. Ammonia nitrogen excretion was positively correlated with intake (£ ~ 0.05; Fig. 4). Addition of benzoic acid at 0.33% DM to Douglas-fir needles elevated Nd excretion by 9%. Addition of monoterpenes at 2.5 and 5.0% of the DM to needles of Douglas-fir increased excretion of Nd by 5 and 39%, respectively. It seems clear that the excretion of nitrogen which can be recovered by micro-kjeldahl analysis is directly related to metabolic detoxification of toxins. Which class of toxins is primarily responsible for elevated nitrogen excretions is not certain, but an examination of toxicology literature and the data gathered so far can lend some insights. Xenobiotic compounds ingested in food present different problems to animals depending on whether they are lipophilic (hydrophobic) or hydrophilic. Lipophilic compounds (such as monoterpenes) are readily absorbed, have access to cell organelles, and are difficult to excrete. Their lack of solubility in water means they are not likely'to be leached from plant material. Absorption thus depends largely on the extent to which plant cells containing these compounds are physically disrupted by the animal's digestive apparatus. Hydrophilic compounds (such as phenolic acids) should be easily leached from plant material but will be absorbed readily only if they are relatively small compounds. �162 DOUGLAS FIR 300 .. Z ~ Z 0 ~ ~ ~ Y = -179.754 + 4.7773xR SUBALPINE FIR 350 = 0.92 280 260 240 Z ~ 0 • 220 ~ ~ ~ • 200 150 75 80 85 95 90 100 20 100 LODQEPOLE 70 100:-----.-----r----.-----r----~ 30 40 50 6C 70 80 PINE ENGELMANN 300 • Z ~ ~ ~ 140 z • 220 180 • • riA • 50 • SPRUCE Y = - 30.5648 + 5.3747xR = 0.96 350 Y = 89.2089 + 1.3423xR = 0.35 • 40 OM CONSUMPTION 400 260 30 60 OM CONSUMPTION Z • 250 • 180 70 0 • 300 Z 200 ~ Y = 58.0405 + 2.8833xR = 0.66 ~ • • • 300 Z 250 ~ ~ ~ 200 o 150 100+----.~--,-----~---r----r---~ 65 70 75 80 85 60 OM CONSUMPTION 90 OM CONSUMPTION Fig. 3. Relationship between ammonia nitrogen excretion and dry matter consumption when captive blue grouse fed on needles of 4 species of_conifers. �163 400 y = 34.104+ 3.3149xR"2 = 0.620 • • 300 • • <t Z 0 • • ::a: ::a: <t 200 - • • • • •• •• • I •• • • • 100~--~----~---r----r---~--~----~---' 50 60 70 40 80 .OM CONSUMPTION Fig. 4. Relationship between ammonia nitrogen excretion-(mg) and dry matter consumption (g) when captive blue grouse fed on 1-2, 3-4, and 5-6 year old needles of old and young Douglas-fir. �164 Once absorbed, xenobiotics undergo phase I and phase II biotransformation reactions (Fig. 5) mitigated by a complex host of enzymatic pathways (Klaassen et ale 1986). Phase I reactions expose or add functional groups which makes the compounds more hydrophilic (increasing their excretability) and makes them susceptible to phase II reactions. In phase II reactions the compound or a phase I derived metabolite is covalently linked to an endogenous molecule, producing a conjugate. These conjugates are more easily secreted than the parent compounds. Conjugating moieties utilized depend on the structure of the xenobiotic, but typically glucuronic acid, sulfates, or amino acids are employed. There are several important points to consider about detoxification. It is energetically expensive. There is an ATP requirement to drive the reaction and also to produce the substrates. Energy stored in the substrate used for conjugation is lost upon excretion. Glucuronic acid is synthesized from glucose via ascorbate (vitamin C), which means when a xenobiotic is conjugated to glucuronic acid a molar equivalent of glucose is lost and vitamin C requirements may rise as well. There is also a nitrogen cost in most cases. This is either because the molecule used for conjugation contains nitrogen (e.g. ornithine, glycine), or because the conjugate is derived from a nitrogen containing compound. For example, the sulfur group in the cofactor used for sulfotransferase reactions is donated from cysteine, and methionine donates methyl groups for similar methylation reactions. Most xenobiotics can enter several detoxification pathways. The route used at any given time depends on the concentration of the compound, the energy status of the animal and many other factors. For instance the sulfation pathway has a high affinity but low capacity for conjugation of phenols. The major alternative reactions, glucuronidation and amino acid conjugation, have low affinity but a much higher capacity. saturation of high affinity, low capacity pathways may have been indicated by the pattern of nitrogen excretion following ingestion of 3 levels of monoterpenes. Doubling monoterpene levels over levels already present in Douglas-fir needles increased nitrogen excretion only 5%. Doubling this level (4x baseline) increased nitrogen excretion by 39%. There is some information available on how specific defense compounds present in conifer needles are metabolized and excreted (summarized in Fig. 5). Chickens conjugate benzoic acid (found in spruce) primarily with ornithine and to a lesser extent with glycine and glucuronic acid (Baldwin et ale 1960, Nesheim and Garlich 1963, Bridges et ale 1970). More complex phenolic monomers, of which there are several in conifer needles, are oxidized to benzoic acid and then conjugated with ornithine (Crowdle and Sherwin 1923), or conjugated directly without transformation. Polyphenolic compounds such as tannic acid are hydrolysed in the gut to gallic acid, absorbed and methylated to 4-0-methyl gallic acid, or decarboxylated to pyrogallol (Potter and Fuller 1968, Kadirvel et ale 1969). Methionine and choline are the probable methyl group donors. Addition of methionine, �165 choline, cysteine and arginine to diets containing as much as 1% tannic acid alleviated the growth suppressing effects of tannic acid (Fuller et al. 1967, Rayudu et al. 1970). This implies that some conjugation of gallic acid (the hydrolysis product of tannic acid) with ornithine also occurs (the arginine serving as a source of ornithine) . The pathway of detoxification and excretion of monoterpenes has not been studied in birds. In mammals monoterpenes are conjugated with glucuronic acid and excreted (Dean et al. 1967, Eberhardt et al. 1975, Dash 1988). It is likely that this pathway or ornithine conjugation predominates in birds as well. The metabolism of diterpene resin acids, which make up from 1-3% of the DM of conifer needles, has also not been studied. Conjugation with glucuronic acid and/or amino acids following appropriate transformations seems probable. It is apparent that the major classes of plant defense compounds share simiiar detoxification pathways (Fig. 5) and that these pathways consume amino acids and elevate nitrogen excretion. The means by which this nitrogen is excreted as ammonia or ammonium ion is by no means clear. I propose 2 mechanisms which may account for elevated ammonia excretion following metabolism of toxins. 1) Amine groups cleaved off of amino acids (cysteine, methionine, choline) to generate carbon skeletons for methylation or sulfation of toxins are transported to the kidney and excreted as ammonium ion (NH4+). Low protein diets and weight loss/starvation, conditions prevalent on spruce and subalpine fir, increase NH4+ excretion in chickens relative to other urates (Skadhauge 1983). 2) Glucose needed to produce glucuronic acid for conjugation will likely result from metabolism of carbon skeletons produced by catabolism of protein reserves on toxic diets (i.e. spruce and fir). since low intakes and metabolizable energy contents are inadequate to meet daily energy needs dietary carbohydrates will not provide excess glucose for synthesis of glucuronic acid. Amine groups generated by this catabolic process could elevate ammonia excretion as above. Since retrograde transport of urine from the cloaca to the ceca has been demonstrated (Mortensen and Tindall 1981), it is possible this nitrogen would continually cycle until fixed by bacteria. This may be prevented by the strong tendency of ammonium ion to complex with and precipitate uric acid out of colloidal suspension (Skadhauge 1983), thereby preventing the whole complex from being washed back to the ceca. The conjugation of xenobiotics in conifer needles with glucuronic acid or amino acids may represent a potential bottleneck in detoxification, either because of enzyme kinetics or substrate limitation. Tannins, phenolic monomers, monoterpenes and diterpene resin acids together may comprise 5-10% of the DM of conifer needles and pose a formidable energy and nitrogen cost to detoxify (Fig. 5). If these compounds singly or in toto overwhelm detoxification pathways, grouse may respond by lowering intake to hold the detoxification load to a manageable level. �166 XENQBIQTIQ Monoterpenes Tannins -. PHASE 1 TRANSFORMATION Phenolics gut hydrolysis Resin acids / Add or remove functional groups to facilitate phase 2 reactions cysteine ~methionine PHASE 2 QQNJUGATIQN Glycine Ornithine sultate ~ fmethYI carbon skeleton plus NH 3 EXCRETED (Bile or urine) Hippuric acid Dibenzoyl ornithine Glucuronic acid conjugate Sulfate eOOH 4-0-methyl gallic acid eOOH ~9 o-~-o 8 ~ O-CH 3 ~ig. 5: Probable pathways of detoxification of xenobiotics In conlfer needles and structures of excreted conJ.ugt present a es. �167 This strategy exasperates low dietary nitrogen and energy contents, but may have been used by grouse eating spruce and subalpine fir (Remington 1987). Secondary compounds in conifer needles were originally hypothesized to have anti-digestibility effects on blue grouse. Trials with captive birds have indicated that these effects are minor. These compounds depress intake (anti-feedant) and incur sUbstantial metabolic costs of detoxification, particularly in nitrogen. Further experimental and analytical work will focus on elucidating which classes of compounds are primarily responsible for these costs. Analysis of detoxification products in excreta is a promising approach. LITERATURE CITED Asquith, T.N., and L.G. Butler. 1985. Use of dye-labelled protein as spectrophotometric assay for protein precipitants such as tannin. J. Chern. Ecol. 11:1535-1544. Baldwin, B.C., D. Robinson, and R.T. Williams. 1960. Studies in detoxification. The fate of benzoic acid in some domestic and other birds. Biochem. J. 76:595-600. Bridges, J.W., M.R. French, R.L. smith, and R.T. Williams. The fate of benzoic acid in various species. Biochem. 118:47-51. 19700 J. Cade, B.S. 1985. Winter habitat preferences and migration patterns of blue grouse in Middle Park, Colorado. M.S. Thesis, Colorado State Univ., Fort Collins. 101pp. Crowdle, J.H., and C.P. Sherwin. 1923. Synthesis of amino acids in-the animal organism. II. The synthesis of ornithine in the body of the fowl. J. BioI. Chern. 55:365. Dash, J.A. 1988. Effect of dietary terpenes on glucuronic acid excretion and ascorbic acid turnover in the brushtail possum (Trichosurus vulpecula). Compo Biochem. Physiol. 89B:221-226. Dean, F.M., A.W. Paice, A.P. Wade, and G.S. Wilkinson. Uroterpenol B-D-Glucuronide. J. Chern. Soc. London 19:1893-1896. 1967. (C) Eberhardt, I. H., J. McNamara, R.J. Pearse, and I. A. Southwell. 1975. Ingestion and excretion of Eucalyptus punctata D.C. and its essential oil by the koala, Phascolarctos cinereus (Goldfuss). Aust. J. Zool. 23:169-179. Farner, D.S., and J.R. King, eds. 1972. Avian biology. Vol. II. Academic Press, New York, N.Y. 612pp. �168 Fuller, H.L., S.I. Chang, and D.K. Potter. 1967. Detoxification of dietary tannic acid by chicks. Nutr. 91:477-481. J. Gray, M. 1978. Absorption of polyphenols by polyvinylpyrrolidone and polystyrene resins. Phytochemistry 17:495-497. Kadirvel, R., G.V.N. Rayudu, and P. Vohra. 1969. Excretion of metabolites of tannic acid by chickens with and without ceca. Poult. Sci. 48:1511-1513. Klaassen, C.D., Amdur, M.D., and J. Doull, eds. 1986. Casarett and Doull's Toxicology, 3rd ed. McMillan Publ. Co., New York, N.Y. 974pp. McLeod, M.N. quality. 1974. Plant tannins - Their role in forage Nutr. Abstr. and Rev. 44:803-815. Mehanso, H., A.E. Hagerman, S. Clements, L.G. Butler, J. Rogler, and D.M. Carlson. 1983. Modulation of proline rich protein biosynthesis in rat parotid glands by sorghums. Proc. Natl. Acad. Sci. 80:3948-3952. Mortensen, A., and A. Tindall. 1981. Cecal decomposition of uric acid in captive and free ranging willow ptarmigan (Lagopus lagopus lagopus). Acta Physiol. Scand. 111:129133. Moss, R. 1977. Digestion of heather spring. Condor 79:471-477. --- , and I. Hanssen. 1980. and Rev. B. 50:555-567. by red grouse Grouse nutrition. during the Nutr. Abstr. Nesheim; M.C., and J.D. Garlich. 1963. Studies on ornithine synthesis in relation to benzoic acid excretion in the .domestic fowl. J. Nutr. 79:311-317. Potter, D.K., and H.L. Fuller. dietary tannins in chicks. 1968. Metabolic fate of J. Nutr. 91:477-481. Rayudu, G.V.N., R. Kadirvel, P. Vohra, and F.H. Kratzer. 1970. Effect of various agents in alleviating the toxicity of tannic acid for chickens. Poultry Sci. 49:1323-1326. Remington, T.E. 1987. Food selection and nutritional ecology of blue grouse during winter. Job Prog. Rep., Colorado Div~ Wildl. Fed. Aid. Proj. 01-03-045 (W-37R). Apr. Pp. 177-198. Robbins, C.T., T.A. Hanley, A.E. Hagerman, O. Hjeljord, D.L. Baker, C.C. Schwartz, and W.W. Mautz. 1987. Role of tannins in defending plants against ruminants: reduction protein availability. Ecology 68:98-107. in �169 Skadhauge, E. 1983. Formation and composition of urine. Chpt. 6 in B.M. Freeman ed., Physiology and Biochemistry of the Domestic Fowl. Academic Press, New York, N.Y. Zwickel, F.C., and J.F. Bendell. 1967. A snare for capturing blue grouse. J. Wildl. Manage. 32:456-468. Prepared by Approved by ��171 JOB PROGRESS REPORT State of: Colorado Project: W-152-R Avian Research Work Plan: 12 Job Title: Chronology of Breeding and Nesting Activities of Wild Turkeys in Relation to Timing of the Spring Hunting Season Period Covered: Author: Job 15 --- 01 January through 31 December 1987 Richard W. Hoffman Personnel: C. E. Braun, R. W. Hoffman, R. L. Holder, and T. B. Lundt, Colorado Division of Wildlife ABSTRACT Efforts to trap wild turkeys (Meleagris gallopavo) in 1987 were unsuccessful. Few birds were located in the study area and those that were could not be attracted to bait sites. The decision was made to wait and attempt trapping on the study area in 1988 rather than to trap elsewhere in 1987. Hunter activity and harvest were monitored in 1987 through use of a permit system and wing collection program. Based on a 100% survey, 3,670 spring hunters harvested 575 turkeys (16% success) and 1,314 fall hunters harvested 278 turkeys (21% success). Las Animas County accounted for 25 and 29% of the spring and fall harvest, respectively. Public-land supported about 55% of the hunting pressure, but produced only 42 (spring) and 36% (fall) of the harvest. Hunter success was better on private (spring = 28%, fall = 40%) than public (spring = 12%, fall =·15%) land. The wing collection program sampled 66% of the spring harvest and 65% of the fall harvest. Merriam's dominated (>92%) in the·harvest samples. Bearded hens comprised 3% (N = 10) of the sample. Seventy-nine percent of the spring harvest of MerrIam's (males only) were adults compared to 59% for Rio G~andes. The fall harvest was comprised I}f 51% juveniles, 4% subadults, and 45% adults (excluding Rio Grandes due to inadequate sample). Sex ratios favored females in the fall harvest. ��173 CHRONOLOGY OF BREEDING AND NESTING ACTIVITIES OF WILD TURKEYS IN RELATION TO TIMING OF THE SPRING HUNTING SEASON Richard W. Hoffman P. N. OBJECTIVES 1. Document the timing of winter flock dispersal, onset of gobbling, peaks of gobbling, nest initiation, onset of incubation, and peak of hatch in relation to timing of the spring season. 2. Describe the gonadal cycle of females and compare the reproductive condition of females in relation to timing of the spring season. 3. Measure the abandonment rate of incubating females to varying levels of human disturbance around the nest. 4. ~bnitor hunter activity and harvest of wild turkeys on a statewide basis. SEGMENT OBJECTIVES 1. Review literature pertinent to the objectives of this study. 2. Trap and instrument 40 wild turkeys (6 males, 34 females) with tailor poncho-mounted radio trasmitters in December-February.- 3. Document timing of winter flock break-up. 4. Document onset of gobbling and peaks of gobbling activity. 5. Document onset of egg laying, incubation, and peak of hatch. 6. Measure effects of human disturbance on rate of nest abandonment. -7. Conduct a hunter questionnaire- wing collection program using a permit system and mail wing survey. 8. Compile data, analyze results, and prepare progress report. DESCRIPTION OF STUDY AREA The study area, located southwest of Trinidad, Colorado in Las Animas County, was previously described (Hoffman 1987). METHODS A detailed account of the methods used in this study were reported by Hoffman (1987). �174 RESULTS AND DISCUSSION Trapping Trapping operations were initiated in January 1987 and continued through mid-April 1987. Except for a flock of 20-30 birds in Sowbelly Canyon, no other turkeys or their sign were found in Longs Canyon or any of its tributary canyons. Efforts to trap the birds in Sowbelly Canyon were unsuccessful as they could not be attracted to bait sites. Instead, they preferred to feed on hillsides rather than in canyon bottoms where they could be trapped. Several different baits were offered to no avail. Cattle were also a problem as they consumed the oat hay and trampled the bait site, including the cannon nets and wire leads. The lack of use of bait sites was attributed to an abundant supply of pinon (Pinus edulis) nuts. Bait sites were placed at other known turkey use areas in Longs, Colorow, Saruche, Martinez, and Little Martinez canyons. No birds were observed at any of these sites. Flocks were found near Lake Dorothey and Spanish Peaks. However, because of access and landowner problems, it was not considered feasible to trap these flocks. In addition, the resulting data would not have been directly comparable with that collected in 1986. It was considered better to skip a year and try to trap at the same sites in 1988 than to trap at another location in 1987. Consequently, trapping operations were terminated on 15 April 1987. This was the latest date to trap and still meet the objectives of the study. Hunter Compliance - Permit System A total of 4,257 permits was issued for the spring season and 4,607 licenses were sold. Hunter compliance with the spring permit requirement was therefore 92%. Questionnaires were sent to all permit holders by 1 June 1987 of which 58% were returned. A followup questionnaire was mailed to the non-respondents 3 weeks later and 527 additional responses were received. The combined return rate for the first and second mailing was 70% (Table 1). There were more permits issued (1,630) for the fall season than there were licenses sold (892). The reason was that unsuccessful spring hunters who wanted to hunt the fall season were not required to purchase another license, but were required to obtain a fall permit. Consequently, total license sales and total permits issued were not directly comparable in evaluating hunter compliance. Instead, hunter compliance was measured as the proportion of new license buyers who also obtained a permit. The estimate was 87% (776 of. 897). Questionnaires were sent to the 1,630 fall permit holders plus the 121 license buyers who did not obtain a permit by 20 October. Fifty-nine percent were returned by 15 November 1987. On 20 November 1987, a followup questionnaire was sent to the 717 non-respondents and 217 replied. Seventy-two percent of the fall hunters responded to the questionnaire (Table 1). �175 Table 1. Response to the 1987 spring and fall turkey harvest survey. Surveys mailed Surveys returned Percent return Non-deliverable 1st Spring 2nd Totals 1st 4,257 2,472 58 83 1,785 527 30 38 4,257a 2,999 70 121 1,751 1,036 59 50 Fall 2nd Totals 717 217 30 6 1,75la 1,253 72 56 aTotal hunters sampled. Hunter Activity and Harvest - Questionnaire Projected estimates for the spring season indicated that 3,670 hunters harvested 575 turkeys for a success rate of 16% (Table 2). Total kill, including a reported crippling loss of 19%, was estimated at 713 birds. Spring hunters averaged 3.6 days afield over the course of the 30-day season from 18 April to 17 May. There were 64% fewer hunters that participated in the fall season (1,314 hunters) and 52% fewer birds (278) were harvested (Table 3). However, hunter success (21%) was higher and crippling loss (18%) was slightly lower. Hunters in fall spent 2.8 days afield or about one day less than hunters in spring, but hunters had only 16 days (19 Sep-4 Oct) of hunting which included just 3 weekends. The spring season lasted 14 days longer, allowing for 2 additional weekends of hunting opportunity. Most hunting pressure and harvest occurred on opening weekend during both seasons CTable 4). Pressure and harvest did not change substantially over the remainder of the fall season. There was an increase in pressure on weekends during the spring season, but this was not always associated with a corresponding increase in harvest. The Southeast Region accounted for over 77% of the spring and fall harvest (Tables 5 and 6). Las Animas County was the leading harvest area with 25 and 29% of the spring and fall harvest, respectively. Public land supported 55% of the spring hunting pressure and 54% of the fall pressure, but produced only 42 (spring) and 36% (fall) of the harvest CTable 7). Hunter success averaged 24% on the spring limited permit areas, exceeding the statewide success rate of 16% on all but 2 areas (Table 8). An eastern plains limited permit area (unit 96) supported the highest hunter success rate (33%). It was not advantageous in terms of success to hunt on a limited permit area during the ~all season as only 27 of 220 (12%) fall limited permit holders were successful (Table 8). However, hunter success on 2 of the 4 fall permit areas surpassed the statewide average. It was a definite advantage to hunt on private (spring = 28% success, fall = 40% success) vs. public land (spring = 12% success, fall = 15% success) in both seasons. �f-' Table 2. -...J 1987 spring turkey harvest and hunter activity. 0' Mailing Descriptive statistic N in sample N hunters % hunters N hunters observing turkeys % hunters observing turkeysb N successful hunt~rs (harvest) % successful huntersb N hunter dabs Days/hunter Crippling loss % crippling loss Total harvest 1st 2nd 2,472 2,151 87 1,441 67 394 18 7,720 3.6 79 17 473 527 450 85 274 61 53 12 1,647 3.6 22 29 75 aNon-respondents. bBased only on those license holders who actually hunted. L 2,999 2,601 87 1,715 66 447 17 9,367 3.6 101 18 548 Projected for Totals 1,258a 1,069 85 652 61 128 12 3,848 3.6 37 29 165 4,257 3,670 86 2,367 64 575 16 13,215 3.6 138 19 713 �Table 3. 1987 fall turkey harvest and hunter activity. Mailing DescriEtive statistic .!:! in sample N hunters % hunters N hunters observing turkeys % hunters observing turkeysb N successful hunters (harvest) % successful huntersb N hunter dabs Days/hunter Crippling loss % crippling loss Total harvest 1st 1,036 779 75 427 55 182 23 2,102 2.7 40 18 222 2nd 217 162 75 87 54 29 18 483 3.0 6 17 35 E 1,253 941 75 514 55 211 22 2,585 2.7 46 18 257 Projected for 498a 373 75 201 54 67 18 1,119 3.0 14 17 81 Totals 1,751 1,314 75 715 54 278 21 3,704 2.8 60 18 338 aNon-respondents. bBased only on those license holders who actually hunted. •..... -.....J -.....J �178 Table 4. Chronological distribution of hunting pressure and harvest during the 1987 spring and fall wild turkey seasons.a Date 1st 1st 2nd 2nd 3rd 3rd 4th 4th 5th weekend week weekend week weekend week weekend week weekend Totals Spring Hunter da~s N % Fall Harvest N % Hunter da~s % N Harvest N % 2,345 1,117 1,529 657 1,043 571 782 509 814 25 12 16 7 11 6 8 6 9 134 55 72 36 28 31 26 24 17 32 13 17 8 7 7 6 6 4 883 459 539 284 331 35 19 22 11 13 94 30 33 22 28 45 14 16 11 14 9,367 100 423 100 2,496 100 207 100 aBased on hunter days and harvest that could be assigned to specific time periods. Seventy-seven percent of the birds harvested during the spring season were taken before noon; 58% were harvested betwen 0500 and 0900 hours (Table 9). Only 29% were not associated with other birds at the time of harvest (Table 10). Most (50%) were taken from flocks comprise of 1-5 birds. The remaining 21% were taken from flocks with 6 or more birds. There was no indication that hunters encountered smaller flocks as the season progressed. Hens undoubtedly were present in the larger flocks, which suggests they were still receptive to males and not incubating. Wing Collection Program Limitations - The validity of any population indice calculated from harvest samples is dependent upon the assumption that the different age and sex classes are harvested in proportion to their occurrence in the population. Long-term population and harvest data are often necessary to test this assumption. Such data are not available for the Merriam's wild turkey in Colorado or elsewhere throughout its range. In addition, if wings are collected over a broad geographic area, they may not accurately reflect the characteristics of local populations. These limitations do not preclude the use of wing data as a useful tool in formulating management strategies. Biologists must be aware of them and use caution in interpreting the data. Compliance - Of the 447 successful spring hunters who responded to the questionnaire, 303 (70%) said they returned a wing. However, 377 wings were processed, meaning 74 successful hunters who did not respond to the questionnaire still returned a wing. The wing collection program sampled 66% (377/575) of the spring harvest. �179 Table 5. Wild turkey harvest by county, Game Management Unit, and Region, Spring 1987. County Las Animas Fremont Huerfano Custer Pueblo Dolores ] Montezuma Mesa E1 Paso Logan ] Washington Morgan Larimer Yuma ""1 Ki t Carson-! Archuleta Douglas Baca Teller Boulder Weld Park Chaffee Bent Jefferson Gilpin Costilla Delta Otero % GMU N % Region 25 li 10 SE SW 6 5 NW 31 26a 64 60 52 26 20 19 15 14 12 8 7 6 84 140 85 71 59 143 24 6 581 17 4 96 15 4 421 103 109 13 3 106 49 43 35 15 4 4 3 3 10 8 7 6 5 5 4 3 3 3 2 1 1 1 2 2 2 1 1 1 1 <1 <1 <1 <1 <1 <1 <1 511 20 2 2 8 8 8 8 2 851 19 51 136 7 2 58 6 1 137 39 125 46 52 83 135 130 30 Totals Unknown 425 22 100 314 74 37 31 9 7 6 25 18 4 425 100 2 2 86 95 40 li8 501 56 123 41 142 78 141 38 144 108. 146 Central % 4 69 77 NE N 2 2 2 5 1 5 5 5 5 1 1 1 1 4 1 4 1 1 4 3 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 425 22 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 100 22 aHarvest was pooled by area which included more than one county or GMU. �180 Table 6. Wild turkey harvest by county, Game Management Unit, and Region, Fall 1987. County N % GMU N % Region N % Las Animas 56 29 24 18 10 10 29 15 13 10 5 5 33 32 27 20 13 10 9 17 16 14 10 7 5 5 SE SW Central NW NE 170 10 8 6 2 87 5 4 3 1 Baca Douglas Mesa Kit Carson Teller Park Yuma El Paso Larimer Costilla 7 7 6 5 4 4 3 2 2 1 4 4 3 3 2 2 2 1 1 <1 84 85 140 143 59 77 58 103 108 109 8 4 Jefferson Chaffee 1 1 <1 <1 8 6 5 4 3 3 3 2 2 2 2 1 1 1 1 4 3 3 2 2 2 2 1 1 1 1 <1 <1 <1 <1 190 21 100 196 15 100 196 15 100 Erenont; Pueblo Huerfano Custer Archuleta Totals Unknowris Ja 69 51 421 123 851 86 46 144 511 501 19 136 40 56 38 .. aHarvest was pooled by area which included more than one county or GMU. Distribution of hunting pressure and harvest by land status during Table 7. the 1987 spring and fall wild turkey seasons. Spring Fall Harvest Hunters Land status Public Private Both Totals N % N % Hunters % N Harvest N % 1,395 794 370 55 31 14 164 224 42 58 491 336 84 54 37 9 74 134 36 64 2,559 100 388 100 911 100 208 100 �181 Hunter success on limited permit areas during the 1987 spring and Table 8. fall wild turkey seasons. Spring Permit areas Lake Dorothey Beaver-Skagway Units 103 and 109 Units 107, 108, 112, 113, 114, 115, 120, 121 Unit 96 Colorado Spgs SWA Spanish Peaks Fall Harvest Success (%) Permits issued Harvest Success (%) 75 20 40 16 4 11 21 20 27 75 30 25 7 7 8 9 23 32 20 70 5 __b 1 23 0 5 33 0 5 6 Permits issued __a __a __a 90 aClosed to fall hunting. bNo restrictions on numbers of hunters during the spring season. Distribution of harvest by time period during the 1987 spring and Table 9. fall wild turkey seasons. Spring Time period 0500 0600 0700 0800 0900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 - 0559 - 0659 - 0759 - 0859 - 0959 - 1059 - 1159 - 1259 - 1359 - 1459 - 1559 - 1659 - 1759 .- 1859 - 1959 Fall N % N % 5 100 63 49 31 19 19 6 7 9 11 10 27 11 5 1 27 17 13 8 5 5 2 2 3 3 3 7 3 1 10 31 33 29 12 9 3 3 1 10 11 14 10 6 17 18 16 7 5 2 2 1 6 6 8 6 aMountain Daylight Time. �182 Table 10. Size of flocks from which turkeys were harvested during the 1987 spring season. Flock size 1 Date of harvest 18-22 Apr 23-27 Apr 28 Apr - 2 fuy 3-7 May 8-12 May 13-17 May Totals 2-5 >10 6-10 N % R % N % N % 46 17 17 12 14 12 28 19 38 34 38 39 79 51 24 18 20 12 47 57 53 51 54 39 19 18 3 2 2 3 11 20 7 6 5 9 24 4 1 3 1 4 14 4 2 9 3 13 118 29 204 50 47 12 37 9 A total of 180 wings was collected from the fall wing survey representing 65% of the estimated fall harvest. Seventy-five percent (160) of the successful hunters responding to the fall questionnaire indicated they returned a wing and 20 successful hunters not responding also returned a wing. Subspecies Composition - The Merriam's wild turkey was the dominant subspecies identified from inspection of wings. It comprised 91 and 96% of the spring (Table 11) and fall (Table 12) samples, respectively, and was harvested in 24 of Colorado's 63 counties. Rio Grande's were taken in 7 counties. Fremont, El Paso, and Pueblo were counties where both subspecies were harvested. The 34 Rio Grande wings collected during the spring season originated from the following areas: 15 from Unit 96, 10 from Units 103/109, 4 from Unit 123, 2 from Unit 95, 2 from Unit 84, and 1 from Unit 69. Two of these areas (Units 95 and 96) were closed to hunting in the fall. The result was that only 8 Rio Grande wi~gs were identified in the fall sample of 180 wings: 7 from Unit 103/109 and 1 from Unit 59. Sex COmposition - Ten (3%) wings examined from the spring sample were from females (Table 11). All were Merriam's and all were assumed to be from legal hens; i.e., bearded hens. Three percent of the total spring harvest (N = 17) is probably a reasonable estimate of the legal harvest of hens. At thIs level of harvest, spring hunting should have minimal impact on the female segment of the population. Examination of wings (Merriam's only) originating from the fall season revealed the sex ratio of adults and subadults combined favored females (1.6 females: 1 male), while the sex ratio of juveniles was about equal (1.2 females: 1 male). The biological implications of these ratios are difficult to interpret without knowledge of the population structure. Hoffman (1962) reported winter counts of 1.6 females: 1 male along the Front Range in southeastern Colorado. The sex ratio of 171 turkeys harvested on the Uncompahgre Plateau during the fall seasons of 1961 and 1963-67 was 1.7 females: 1 male) (Myers 1973). Both ratios were based on combined samples of adults, subadults, and juveniles. A comparable ratio using the 1987 fall harvest data would be 1.4 females : 1 male. Myers' data by age class shows �183 that the sex ratio of adults and subadults (2.5 females : 1 male) and juveniles (1.5 females : 1 male) still favored females. Sex ratios should favor females in a promiscuous species such as the wild turkey where most hens breed but only a portion of the males do. Table 11. Sex, age, and subspecies composition of the spring 1987 wild turkey harvest based on wing analyses. Males Subspecies Merriam's Rio Grande Totals Subadult Adult Females Subadult Adult Totals 60 (18)a 14 (41) 269 (79) 20 (59) 2 (1) 0 8 (2) 0 339 34 74 (20) 289 (77) 2 (1) 8 (2) 373b apercent. bFour additional Merriam's wings were processed but could not be classified to age or sex bringing the total wings collected to 377. Age Composition - Seventy-nine percent of the spring harvest (males only) of Merriam's wild turkeys were adults compared to only 59% for Rio Grande's. Rio Grande populations in Colorado are the result of recent (since 1981) introductions. Available evidence suggest these populations are still increasing and expanding into unoccupied ranges, while populations of Merriam's wild turkeys have remained stable or declined. The age composition of the Rio Grande harvest reflects good production, survival, and recruitment of young birds, attributes indicative of an increasing population. Estimates of nesting success based on observations of radio-marked Rio Grande (58% success) (Schmutz 1988) and Merriam's (20% success) (Hoffman 1987) hens further suggest differences in reproductive output that should be reflected by harvest samples. Subadult males in the increasing Rio Grande populations may not be suppressed by mature males from participating in breeding activities. If so, then subadults should be equally, if not more vulnerable due to their inexperience, to the calling tactics of hunters. The following discussion regarding the age composition of the fall harvest pertains to the Merriam's wild turkey. Samples of Rio Grande wings from the fall season were inadequate for meaningful interpretation. Subadults comprised jus~ 4% of the fall harvest including juveniles and 8% excluding juveniles (Table 12). Biologically, this could be interpreted as poor production in 1986 and subsequent low recruitment into the 1987 population. However, another factor contributing to the low number of subadults is that associated with the onset of primary molt and whether the key feathers (primaries IX and X) for separating adults and subadults are still present at the time wings are collected. If these feathers have already molted, then subadults cannot be distinguished from adults. This was the case as 44% of the males and 24% of the females had completed their primary molt by the fall season. The problem of separating adults and subadults was �I--' Tables 12. Age, sex, and subspecies composition of the 1987 fall harvest based on wing analyses. Adults Females Males Subspecies Merriam's Rio Grandes co ~ Total Subadu1ts Females Males Total Juveniles Females Males N % N % N % N % N % N % N % N % 32 41 25 46 59 75 78 4 45 50 0 0 0 0 7 1 100 100 7 1 4 12 40 0 46 0 47 54 100 1 3 3 Total N 87 3 % Sample size 51 38 172 8 Pou1ts/ hen 1.6 1.0 �185 compounded for males because they start and finish their primary molt sooner than females. A similar problem was confronted in interpreting wing data derived from harvest samples of blue grouse (Dendragapus obscurus) (Hoffman 1985). Misidentification of subadults is not a problem in spring when birds are just beginning their primary molt. Percent juveniles in the harvest (51%) and the ratio (1.6:1) of juveniles adult and subadult females were used as indicies to productivity. The 2 indices suggested only fair production of young in 1986. LITERATURE CITED Hoffman, D. M. 1962. The wild turkey in eastern Colorado. Game and Fish. Tech. Publ. 2. 49pp. Hoffman, R. W. inferences. to 1985. Blue grouse wing analyses: methodology Colorado Div. Wildl. Spec. Rep. 60. 2lpp. Colorado Dep. and population 19B7. Chronology of breeding and nesting activities of wild turkeys in relation to timing of spring hunting seasons. Prog. Rep. Colorado Div. Wildl. Fed. Aid Proj. W-152-R. Apr. 1987. Pp. 199-232. Myers, G. T. 1973. The wild turkey on the Uncompahgre Plateau. Colorado Vivo Wildl. Fed. Aid Proj. W-37-R. l53pp. Final Rep. Schmutz, J. A. 1988. Reproductive performance and habitat use of Rio Grande wild turkeys. M.S. Thesis, Colorado State Univ., Fort Collins. 5lpp. ��187 JOB FINAL REPORT Colorado State of: Project: W-152-R (01-03-045) : Job Avian Research 16 Work Plan: 12 Job Title: Reproductive Performance and Habitat Use of Rio Grande \Vild ur eys ~eriod Covered: Author: 01 January 1986 through 31 July 1988 Joel-A. Schmutz Personnel: W. Andelt, M. Baker, J. Ratti, G. White, Colorado State University; C. Braun, J. Corey, T. Davis, M. Etl, D. Hall, R. Hoffman, W. Miles, J. Schmutz, S. Steinert, Colorado Division of Wildlife , ABSTRACT Reproductive performance, nest habitat use, and brood habitat use of Rio Grande wild turkeys (Meleagris gallopavo intermedia) were studied along the South Platte River in northeast Colorado in 1986-87. Data were collected from 13 and 18 radio-marked hens in 1986 and 1987, respectively. Yearlings dispersed farther (K = 35.5 km) than adults (K = 14.3 km) from winter flocks to nest sites. Thirty of 31 hens were known to attempt nesting. Eighteen hens hatched eggs. Adult hens nested earlier than yearlings. Earlier first nest.attempts tended to be more successful than later first attempts. Among first nest attempts by adults, earlier nests had. larger clutches. Adults laid larger eggs than yearlings but there .. :was no difference between age classes in clutch size or number of eggs hatched. Egg size was not related to clutch size or time of season. Thirty-three of 35 nests were in ungrazed riverbottom. Early nests were more likely to be in snowberry (Symphoricarpos sp.) clumps (vs , mixed forbs and grasses) than later nests. Forbs and grasses provided little cover early in the season but did not differ from snowberry later in the season. Nest plots had greater overstory canopy cover, more shrubs, fewer grasses, and greater understory cover and height than adjacent random plots. Nesting habitat did not differ between age classes or nest fates. Minimizing probabilities of nest depredation may be the proximate cause of chronological shifts in nest habitat use. Seventy-eight percent of 191 macrohabitat locations were in the riverbottom. Use of riverbottom, agricultural uplands, and the edge between these habitat types was dependent on time of day and may be related to the thermal environment. Brood use of grazed areas increased with brood age. Microhabitat �188 use of 14 broods was examined at 47 locations within the riverbottom. Among these locations, grasses were more abundant on brood-use plots than on random plots. Young broods used areas with more shrubs and grasses than older broods. RECOMMENDATIONS The results of this research suggest management strategies but do not test the effect of such strategies. Further research involving manipulations to test specific management options is required. 1. Do not allow cattle grazing on state wildlife areas unless within the context of a carefully designed experiment. 2. Burning of standing dead grass on state wildlife areas should only be done on areas outside the riverbottom. 3. Open riverbottom from Sterling to Crook to hunting. 4. Timing of the spring hunting season for Rio Grande wild turkeys alo~g the South Platte River should remain as it was set in 1986-88. 5. Expansion of this population will occur without transplant operations. If more rapid expansion is desired, transplanted turkeys should be moved >30 km from the closest winter flock. The most immediate need in further research is to develop a suitable method to estimate turkey densities. Such a method would allow the Division of Wildlife to assess the impact of hunting seasons and would be an integral part of any additional research including testing of density effects on reproductive parameters and habitat manipulations. Aerial surveys during winter when there is snow cover is likely the best approach. The actual sampling methodology and analysis requires investigation. �189 ACKNOWLEDGMENTS This project required the cooperation of the Colorado Division of Wildlife (CDOW), Colorado State University, and the landowners along the South Platte River. Funding was provided by the CDOW through Federal Aid in Wildlife Restoration Project W-lS2-R. For varied assistance in all aspects of this project, I am indebted to numerous CDOW employees including C. Braun, J. Corey, T. Davis, M. Etl, D. Hall, R. Hoffman, W. Miles, and S. Steinart. Clait Braun deserves special thanks for his encouragement, candid discussions, and concern for my development as a biologist. I thank Dr. Bill Andelt for serving as my major advisor. much from his friendship and thorough critiques. I learned I also thank Drs. Mike Baker and Rick Knight for serving on my graduate committee. perspectives helped open my mind to new ideas. Their I appreciate Dr. John Ratti for bringing me to CSU and serving as my initial advisor. I am grateful to Dr. Gary White for all he taught me in the classroom and at the bar. His forthright approach, constructive criticisms, professional conduct, and fervent enthusiasm were inspiring. My time in the field was greatly enriched by Tim Davis and the whole Etl clan - Mike, Paula, Cara, Jamie, and Sadie. support and friendship helped me immeasurably. for her dinners. Their logistical My stomach thanks Paula �190 Many thanks go to my second family - my fellow graduate students. Morning coffee, FAC's, volleyball, basketball, and skiing were all great. In particular, I want to thank Tanya and CA for opening up their house and their hearts to me. And finally, I thank my first family - mom, dad, and all the way down to Namu. Their unflagging love, interest, and s~pport for me through all my pursuits provides me with the strength to follow my dreams. �191 Table of Contents Page ABSTRACT OF THES IS ACKNOWL EDGMENTS iii v LIST OF TABLES ..................................•.................. ix LIST OF FIGURES ....................•................................ x Chapter 1. REPRODUCTIVE PERFORMANCE OF RIO GRANDE WILD TURKEYS 1 Study Area 2 Methods 3 Results 4 Discussion 14 Literature Cited 2a Chapter 2. NEST HABITAT USE OF RIO GRANDE WILD TURKEYS 23 Study Area ..............•....................................... 24 Methods 25 Habitat Measurements ...........•............................. 25 Statistical Analyses 27 Resul ts 27 Discussion 32 Literature Cited 38 Chapter 3. BROOD HABITAT USE OF RIO GRANDE WILD TURKEYS 41 Study Area 42 Methods 43 Resul ts 45 Macrohabi tat Use 45 �192 Table of Contents (cant/d) Page Microhabi tat Use 46 Di scuss i on .......•.............................................. 46 Literature 50 Cited �193 List of Tables 1.1 Initiation dates of first nest attempts by wild turkeys in northeast Colorado, 1986-87 8 1.2 Body weights (kg) of wild turkeys captured in February 1986-87 in northeast Colorado ~.17 2.1 Habitat variables at wild turkey nest and random plots in northeast Colorado, 1986-87 31 2.2 Habitat variables at wild turkey nests in snowberry and other vegetation in northeast Colorado, 1986-87 33 2.3 Numbers of successful and depredated wild turkey nests in snowberry and mixed forbs and grasses in early and late season in northeast Colorado, 1986-87 •............................... 34 3.1 Microhabitat variables at wild turkey brood-use « 22 days old) and random plots in early and late season in northeast Colorado, 1986-87 47 �194 List of Figures Figure Page 1.1 Winter flock and nest locations of wild turkeys in northeast Colorado, 1986-87. Shaded portion of state map represents study area .............................................•..... 7 1.2 Cumulative nest initiation for wild turkeys in northeast Colorado, 1986-87 _ 10 1.3 First nest initiation as a predictor of clutch size in adult wild turkeys in northeast Colorado, 1986-87 13 1.4 Winter body weight as a predictor of nest initiation date in yearling wild turkeys in northeast Colorado, 1986-87 16 2.1 Probability of wild turkeys nesting in snowberry as a function of nest initiation date in northeast Colorado, 1986-87. Regression predicted values ± SE from y = 0.0414! - 6.0542, where initiation date was the Julian date 30 �195 Chapter 1 REPRODUCTIVE PERFORMANCE OF RIO GRANDE WILD TURKEYS The Rio Grande wild turkey (Meleagris gallopavo intermedia) is endemic to northern Mexico, Texas, Oklahoma, and southern Kansas (Aldrich 1967). Transplanting programs have extended the range of this subspecies from California (Graves 1975) to North Dakota (Aldrich 1967). Although several studies of Rio Grande wild turkeys have been reported from Texas (e.g., Watts 1968, Beasom and Pattee 1980, Ransom et al. 1987), little is known about the reproductive ecology of newly established populations in other habitats. Information on reproductive performance of this subspecies is necessary to understand its population dynamics. Beasom and Pattee (1980), working in south Texas, reported productivity of wild turkeys was correlated with the amount of previous fall and current spring rainfall. Greater soil moisture resulting in more vigorous plant growth of higher nutritional value was the hypothesized mechanism affecting reproduction. On the Welder Wildlife Refuge in south Texas, Ransom et al. (1987) postulated that predation, primarily of nests, was the major limiting factor for Rio Grande wild turkeys. In more northerly habitats, winter severity has been suggested as a major factor limiting Eastern wild turkey populations (M. g. sylvestris) (Porter et al. 1983, Gray and Prince 1988). I studied the reproductive performance of an introduced population of Rio Grande wild turkeys in riparian habitats in northeast Colorado �196 in 1986-87. Nesting rates, hen success, and temporal patterns in nest initiation were investigated to better understand the population dynamics of Rio Grande wild turkeys in a non-native, more northerly habitat. STUDY AREA The study was conducted along the South Platte River in Logan, Morgan, and Washington counties in northeast Colorado. Elevation varied from 1,130 to 1,322 m in a gradual east-west gradient. Annual precipitation averaged 36 cm; mean January and July temperatures were -4.5 and 23.5 C, respectively (Natl. Oceanic and Atmos. Adm. 1986). The riverbottom community extended to 1.0 km in width and was dominated by an open-canopied plains cottonwood (Populus sargentii) forest. Discrete clumps of woody shrubs, primarily western snowberry (Symphoricarpos occidentalis), occurred in an understory dominated by cheatgrass brome (Bromus tectorum), prairie cordgrass (Spartina pectinata), inland saltgrass (Distichlis stricta), and a variety of forbs (plant names follow Scott and Wasser [1980]). Lindauer (1983). provided a complete vegetative description of this particular community. Private lands adjacent to the riverbottom were primarily used for production of alfalfa, corn, wheat, and other small grains and row crops. Cattle were grazed at varying intensities both in and adjacent to the riverbottom. The Colorado Division of Wildlife owned approximately one-third of the riverbottom in the study area. lands were not grazed and were used for both consumptive and nonconsumptive recreation. These �197 Sixty Rio Grande wild turkeys from Kansas and Texas were introduced to the study area during 1980-83. No wild turkeys had previously existed in northeast Colorado. METHODS Turkeys were trapped in February 1986-87 with drop-nets and clover traps. Captured birds were classified to age and sex, weighed, measured for carpal and primary feather lengths, and fitted with aluminum leg bands. Turkeys were classified as yearlings « 1 year of age) or adults (> 1 year of age) based on characteristics of P IX and X (Petrides 1942). Females were fitted with transmitters mounted on ponchos (Amstrup 1980) or attached to the central pair of retrices (Bray and Corner 1972). Poncho and tail clip transmitters weighed 29- 32 g and 26-29 g, respectively, and had expected battery lives of 6 months. Turkeys were relocated at least once every 4 days prior to winter flock breakup and dispersal. Once dispersal ceased and individual hens localized, they were relocated every 1-2 days to ascertain nest initiation. Hens that moved in response to my approach were assumed to have not yet initiated incubation. Hens that remained in vegetation clumps as I circled to within 25 m were assumed to be incubating. Locations of incubating hens were flagged so that nests could be found after hatching, depredation, or abandonment. Dispersal distance was measured from the approximate center of the flock winter range to a nest site. Distances were measured parallel to the river because no turkeys were observed> 0.5 km from the riparian area along the river. Differences between ages and years were tested with Mann-Whitney tests. Clutch size and number of hatched eggs were determined from egg shell characteristics. When egg shells were sufficiently intact, �198 lengths and widths were measured with calipers. Clutch and egg size comparisons used data from successful first nest attempts and those unsuccessful first nest attempts whose clutches were observed prior to nest destruction. Differences in clutch size, numbers of eggs hatched, and egg width between age classes were tested using analysis of variance (ANOVA) with age, year, and age-year interactions specified as main effects. Egg widths within a clutch were averaged and the mean value entered into the ANOVA. Nest initiation date as a predictor of clutch size and egg width was examined with linear regression. Hen success was defined as hatching ~ 1 egg during all nest attempts. Differences in hen success between years and age classes were tested with Fisher's exact test. Abandonment caused by observer disturbance and females not attempting to nest were not included in hen success analyses. Nest initiation dates were estimated by counting egg shells and assuming 1 egg laid/day and a 28-day incubation period (Bailey and Rinnell 1967). Initiation dates for unsuccessful nests were estimated by calculating the egg-laying period from the first date of suspected incubation ascertained from activity data. Differences between age classes in nest initiation dates and nest fates were tested with median tests. The power of nest initiation date as a predictor of hen age and nest fate was examined with logistic regression analysis. The relationship between winter body weight and subsequent date of first nest initiation was analyzed using linear regression. The Statistical Analysis System was used for all analyses (SAS Inst. Inc. 1987). RESULTS Five adult and 8 yearling females, and 6 adult and 12 yearling females were radiomarked, respectively, in 1986 and 1987. In 1987 a �199 nest of an unmarked adult was found and the data included in all but the dispersal analyses (age ascertained from egg dimensions). Dispersal distances did not differ between years and the data were pooled. Dispersal began in mid-March with peak movements occurring from the third week in March through the first week in April. Yearlings dispersed farther (n = 18, ~ = 35.5 km, SE = 4.1 km, £= 0.009) from winter flocks to nest sites than adults (n = 11, ~ = km, SE 4.9 km). Three yearling hens dispersed> 14.3 60 km. Within age classes, dispersal was not uniform across the study area (Fig. 1.1). All 12 adult and 19 of 20 yearling females were known to attempt nesting. Adults and yearlings did not differ in date of first nest initiation in 1986, but adults initiated nests earlier than yearlings in 1987 (Table 1.1). Nest initiation date was not a significant predictor of hen age (£ = 0.163). Most (67%) nest initiation occurred between mid-April and mid-May (Fig. 1.2). Fifty-eight percent of nesting hens successfully hatched eggs. Fifteen of 36 nests were destroyed by predators, mostly raccoons (Procyon lotor) and striped skunks (Mephitis mephitis), and 3 were abandoned, 2 of which may have been observer induced. Five hens were attacked while on nests with 1 known mortality, probably by a coyote (Canis latrans). renested twice. Three yearlings were known to renest and 1 adult Hen success was not dependent on age (£ = 0.158). In 1987, 6 of 7 adults hatched eggs compared to only 5 of 12 yearlings, but this difference was not significant (£ = 0.147). of successful first nest attempts (median = Initiation dates 21 Apr) tended to be earlier than unsuccessful first attempts (median = 5 May) (£ = 0.073). Date of nest initiation was a marginally significant predictor of nest fate (f = 0.077). The first nest initiated had a 74 ± 13% (SE) �N o o ( --- --- -..-- .. - ---------------------------------------------_ .. - -- CROOK [J o YAY~( A ~\e DENVER P'" '(\~ y_Yi,,=p,J COLORADO Y A-NEST OF ADULT Y -NEST OF YEARLING F-WINTER FLOCK LOCATION N t r- o FORT MORGAN o l 20 40 KILOMETERS Fig. 1.1. Winter flock and nest locations of wild turkeys in northeast Colorado, 1986-87. of state map represents study area. Shaded portion �201 Table 1.1. Initiation dates of first nest attempts by wild turkeys in northeast Colorado, 1986-87. Year Age Median Range Adult 27 Apr 11 Apr - 6 Jun Yearling 24 Apr 17 Apr - 14 May 16 Apr 10 Apr - 12 Jun 6 May 27 Apr - 2 Jul 20 Apr 10 Apr - 12 Jun 5 May 17 Apr - 2 Jul 1986 0.575 1987 Adult Yearling 0.032 1986-87 Adult Yearling 0.006 a Median test for age differences. • �0 6 W l<l: I- 6 0.8 6 Z - 6 (J) I(/) W 6 0.6 LL 6 0 z 0.4 6 0 6 l- 0 n, • • 6 Z a: 6 0.2 • 0 a: n, • 6 1.0 ! - • • • • • • • • • • • • --• 6 1986 • 1987 6- • 0 30 15 APR Fig. 1.2. 30 15 MAY 30 15 JUN Cumulative nest initiation for wild turkeys in northeast Colorado, 1986-87. N 0 N �203 probability for success whereas the probability for success for the last nest was only 6 ± 9%. Clutch size of adults was not dependent on nest initiation date when all 11 data points were examined (r2 = 0.265, latest nesting adults initiated nests> adult. E= 0.101). The 2 1 month after the next latest The localized behavior of these 2 hens indicated they may have initiated earlier nests that I did not find. With these 2 outliers excluded, nest initiation date was inversely related to both clutch size (r2 = 0.723, £ = 0.004) (Fig. 1.3) and number of eggs hatched (r2 = 0.763, £ = 0.010). Adult clutch sizes (n = 11, ~ = 11.3, SE = 0.68) were not Significantly larger than yearling clutch sizes (n = 10, ~ = 10.0, SE= 0.82, E= 0.233). Numbers of hatched eggs also did not differ between age classes (adults, n yearlings, n = 7, ~ = 8.6, SE = 0.57, = 8, ~ = 10.0, SE 1.0; £ = 0.255). Eggs of adults were wider (n = 12, ~ = 47.97 mm, SE = 0.51, £ = 0.022) than eggs of yearlings (n = 20, ~ = 46.54 mm, SE = 0.31), but there was no relationship between egg width and initiation date or clutch size 0.1, E > 0.10). (£2 < Year and age-year interactions were not significant in any ANOVA (E > 0.10). Poncho-marked birds were not different from tail-clip marked birds in date of first nest initiation, clutch size, number of eggs hatched, or nest success (£ > 0.25 for all tests). Body weight of hens captured in February was a Significant predictor of subsequent first nest initiation date for yearlings but not adults. Lighter weight yearlings nested earlier than heavier yearlings (r2 = 0.226, £ = 0.024). Omission of the 2 latest nesting yearlings appeared justified as these hens did not nest until late June when the effects of winter body condition on nest initiation date were probably inconsequential. Winter body weight accounted for 41% of the �N a p.. 15 I •• 14~ <. 13-j w N (f) I 0 n=9 r2=0.723 • P=0.004 •• 12--i 11 -1 • l- :J 10-, _J • <, 0 • 9--i 8-1 7, ,8 I , 12 I I I , 20 16 " I , 24 I I 28 APR Fig. 1.3. First nest initiation date as a predictor of clutch size in adult wild turkeys in northeast Colorado, 1986-87. �205 variance in nest initiation date for the truncated data set (E = 0.006) (Fig. 1.4). When this data set was examined by years, the relationship was evident in 1986 (n = 7, r2 = 0.525, 10, r2 = 0.041, E= 0.573). E= 0.065) but not in 1987 (n = Mean weight of each age and sex class was lower in 1986 than 1987, although this difference was significant only for adult females (E = 0.056) (Table 1.2). low power due to small sample sizes. Most statistical tests had Thus, small, but real, differences between groups may have gone undetected. DISCUSSION Population dynamics in many birds are affected by differences in reproductive performance between age classes. Compared to yearlings, adult females generally nest more frequently, earlier (Hannon et al. 1982) and with greater success, lay larger clutches (Wallestad and Pyrah 1974, Giesen et al. 1980), and lay bigger eggs that produce young of higher survivorship (Ankney 1980). In wild turkeys, these reproductive parameters are poorly understood. Adult clutch sizes have been reported to be larger (Porter 1978}, smaller (Glidden and Austin 1975, Reagan and Morgan 1980), and not different from yearling clutch sizes (Vangilder et al. 1987). Nest (hen) success was greater in adults in some studies (Vangilder et al. 1987, Vander Haegen et al. 1988) but not in others (Porter 1978, Everett et al. 1980). The high rate of yearling breeding in this study (95%) is consistent with that reported by some investigators (Glidden and Austin 1975, 100%; Porter 1978, 88%; Everett et al. 1980,85%; Vander Haegen et al. 1988, 81%), but in contrast to others (Reagan and Morgan 1980, 31%; Lutz and Crawford 1987, 31%; Wertz and Flake 1988, 0%). In blue grouse (Oendragapus obscurus), non-breeding among yearlings has been attributed to interfemale aggression in high density �N o 0' 30- • ::l 20 0=17 [2=0.410 10 [>=0.006 z J >- « •• 30 20· ~ 10 • • ~ 30 a: Q_ « 20 • 10- J J---T I~ 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 WEIGHT (kg) Fig. 1.4. Winter body weight as a predictor of nest initiation date in yearling wild turkeys in northeast Colorado, 1986-87. �207 Table 1.2. Body weights (kg) of wild turkeys captured in February 1986-87 in northeast Colorado. Inter-year Sex difference n Age X SE (%)a E_b 4.4 0.358 5.1 0.056 Females Adults 1986 5 3.96 0.11 1987 6 4.13 0.14 1986 11 3.42 0.07 1987 17 3.59 0.05 1986 1 8.00 1987 2 8.45 0.50 1986 8 5.51 0.20 1987 4 5.85 0.24 Yearlings Males Adults 5.6 Yearlings 6.1 0.336 a [(1987 mean weight/1986 mean weight) - 1)] x 100. b 1 test for differences in mean weights between years within age and sex classes. �208 populations (Zwickel 1980, Hannon et al. 1982). The interaction between population densities and reproductive performance, particularly the frequency of non-breeding by yearlings, merits further investigation. Delayed yearling breeding (within seasons) has not previously been addressed in the wild turkey literature, although it has been observed in several grouse species (e.g., sage grouse [Centrocercus urophasianus], Petersen 1980; blue grouse [Dendragapus obscurus], Zwickel 1977, Hannon et al. 1982). The long dispersal distances by yearlings observed in this study are consistent with the interfemale aggression hypothesis of delayed yearling breeding suggested by Hannon et al. (1982) for blue grouse, but data on social behavior are lacking. Also, whether these spring movements constitute dispersal vs. migration is not clear. Most temperate bird species are seasonally constrained to nesting when food is most abundant; specifically, the female must have enough body reserves and/or food available to endure the energetic drain of egg-laying and incubation (Perrins 1970). In Missouri, nest initiation dates of Eastern wild turkeys were correlated with spring temperatures over a 4-year period (Vangilder et al. 1987). In both years of my study, spring temperatures were similar and vegetative growth began in early to mid April, corresponding closely to the first observed nest attempts. Onset of wild turkey nesting is likely proximately controlled by spring vegetative growth or a correlate of this parameter, such as temperature. Winter conditions may affect timing of breeding (Murphy 1986) as well as over-winter survival (Haramis et al. 1986) in birds that rely on endogenous reserves. Although it is not clear to what extent wild �209 turkeys use endogenous reserves, one expects an inverse relationship between body condition (roughly indexed by body weight) and both survival and subsequent nest initiation date (Hannon et al. 1988). Porter et al. (1983) found that wild turkey hens in Minnesota that weighed < 4.3 kg were less likely to survive and less likely to breed than heavier hens. In my study, the low observed mortality (no birds died between 1 week after capture and early May in either year) and early nest initiation by lightweight hens suggests that winter conditions do not impact survival and timing of breeding in this population. Breeding too late may be proximally constrained by lower egg production, hen success, and chick survival. In this study, adults laid fewer eggs and experienced marginally higher rates of nest predation as the season progressed. Toft et al. (1984) suggested that ducks optimally apportion their reserves into either many small eggs or few large eggs, depending upon current probabilities of nest and duckling survivorship. They argued that decreasing survival of young in late season selectively favored large eggs that produced young of high survivorship. This inverse relationship between clutch and egg size, and the assumed optimal allocation of a limited energy supply, has been questioned by Rohwer (1988). He found little correlation between these 2 parameters for most waterfowl species examined. In this wild turkey population, the lack of a relationship between clutch and egg size suggests that egg production may not be limited by energetic constraints. Further, breeding early (Vangilder et al. 1987, Hannon et al. 1988) or laying fewer eggs in later nests would increase the time available to renest. Maximizing the opportunity to renest may be �210 important to these wild turkeys as 42% of all nests initiated were depredated. All 4 hens that were known to renest were eventually successful. Although population density and nest predation have been separately suggested as affecting yearling breeding and clutch and egg size and timing of breeding, interaction between these 2 parameters is probable. I suggest that variation in frequency of yearling breeding may impact wild turkey population dynamics as much as nest depredation. Further studies of reproductive performance in wild turkeys should address these parameters simultaneously. LITERATURE CITED Aldrich, J. W. 1967. Taxonomy, distribution, and present status. Pages 17-44 in O. H. Hewitt, ed. The wild turkey and its management. The Wildl. Soc., Washington, D.C. Amstrup, S. C. 1980. A radio-collar for game birds. Manage. 44:214-217. J. Wildl. Ankney, C. D. 1980. Egg weight, survival, and growth of lesser snow goose goslings. J. Wildl. Manage. 44:174-182. Bailey, R. W., and K. T. Rinnell. 1967. Events in the turkey year. Pages 73-92 in O. H. Hewitt, ed. The wild turkey and its management. The Wildl. Soc., Washington, D.C. Beasom, S. L., and o. H. Pattee. 1980. The effect of climatic variables on wild turkey productivity. Proc. Natl. Wild Turkey Symp. 4:127-135. Bray, o. E., and G. W. Corner. 1972. A tail clip for attaching transmitters to birds. J. Wildl. Manage. 36:640-642. Everett, D. D., D. W. Speake, and W. K. Maddox. 1980. Natality and mortality of a north Alabama wild turkey population. Proc. Natl. Wild Turkey Symp. 4:117-126. Giesen, K. M., C. E. Braun, and T. A. May. 1980. Reproduction and nest-site selection in white-tailed ptarmigan. Wilson Bull. 92:188-199. Glidden, J. W., and D. E. Austin. 1975. Natality and mortality of wild turkey poults in southwestern New York. Proc. Natl. Wild Turkey Symp. 3:48-54. �211 Graves, W. C. 1975. Wild turkey management in California. Proc. Natl. Wild Turkey Symp. 3:1-5. Gray, B. T., and H. H. Prince. 1988. Basal metabolism and energetic cost of thermoregulation in wild turkeys. J. Wildl. Manage. 52:133-137. Hannon, S. J., K. Martin, and J. O. Schieck. 1988. Timing of reproduction in two populations of ~illow ptarmigan in northern Canada. Auk 105:330-338. ______., L. G. Sopuck, and F. C. Zwickel. 1982. Spring movements of female blue grouse: evidence for socially induced delayed breeding in yearlings. Auk 99:687-694. Haramis, G. M., J. D. Nichols, K. H. Pollock, and J. E. Hines. 1986. The relationship between body mass and survival of wintering canvasbacks. Auk 103:506-514. Lindauer, I. E. 1983. A comparison of the plant communities of the South Platte and Arkansas river drainages in eastern Colorado. Southwest. Nat. 28:249-259. Lutz, R. S., and J. A. Crawford. 1987. Reproductive success and nesting habitat of Merriam's wild turkeys in Oregon. J. Wildl. Manage. 51:783-787. Murphy, M. T. 1986. Body size and condition, timing of breeding, and aspects of egg production in eastern kingbirds. Auk 103:465-476. National Oceanic and Atmospheric Administration. 1986. Climatological data, Colorado. U.S. Dep. Comm., Natl. Oceanic and Atmospheric Admin. 91(13):12. Perrins, C. M. 1970. The timing of birds' breeding seasons. 112:242-255. Ibis Petersen, B. E. 1980. Breeding and nesting ecology of female sage grouse in North Park, Colorado. M.S. Thesis, Colorado State Univ., Fort Collins. 86pp. Petrides, G. A. 1942. Age determination in American gallinaceous game birds. Trans. North Am. Wildl. Conf. 7:308-328. Porter, W. F. 1978. The ecology and behavior of the wild turkey (Meleagris gallopavo) in southeastern Minnesota. Ph.D. Thesis, Univ. Minnesota, Minneapolis. 121pp. , G. C. Nelson, and K. Mattson. 1983. Effects of winter -----conditions on reproduction in a northern wild turkey population. J. Wildl. Manage. 47:281-290. Ransom, D., Jr., O. R. Rongstad, and D. H. Rusch. 1987. Nesting ecology of Rio Grande turkeys. J. Wildl. Manage. 51:435-439. Reagan, J. M., and K. D. Morgan. 1980. Reproductive potential of Rio �212 Grande turkey hens in the Edwards Plateau of Texas. Wild Turkey Symp. 4:136-144. Proc. Natl. Rohwer, F. C. 1988. Inter- and intraspecific relationships between egg size and clutch size in waterfowl. Auk 105:161-176. SAS Institute, Inc. 1987. SAS/STAT guide for personal computers, version 6 edition. Cary, N.C. 1028pp. Scott, T. G., and C. H. Wasser. 1980. Checklist of North American plants for wildlife biologists. The Wildl. Soc., Washington, D.C. 58pp. Toft, C. A., D. L. Trauger, and H. W. Murdy. 1984. Seasonal decline in brood sizes of sympatric waterfowl (Anas and Aythya, Anatidae) and a proposed evolutionary explanation. J. Anim. Ecol. 53:75~92. Vander Haegen, W. M., W. E. Dodge, and M. W. Sayre. 1988. Factors affecting productivity in a northern wild turkey population. J. Wildl. Manage 52:127-133. Vangilder, L. D., E. W. Kurzejeski, V. L. Kimmel-Truitt, and J. B. Lewis. 1987. Reproductive parameters of wild turkey hens in north Missouri. J. Wildl. Manage. 51:535-540. Wallestad, R., and D. Pyrah. 1974. Movement and nesting of sage grouse hens in central Montana. J. Wildl. Manage. 38:630-633. Watts, C. R. 1968. Rio Grande turkeys in the mating season. Trans. North Am. Wildl. Conf. 33:205-210. Wertz, T. L., and L. D. Flake. 1988. Wild turkey nesting ecology in south central South Dakota. Prairie Nat. 20:29-37. Zwickel, F. C. 1977. Local variations in the time of breeding of female Blue Grouse. Condor 79:185-191. 1980. Surplus yearlings and the regulation of breeding density in blue grouse. Can. J. Zool. 58:896-905. �213 Chapter 2 NEST HABITAT USE OF RIO GRANDE WILD TURKEYS Avian nest habitat selection may be influenced by many factors including predation (Martin and Roper 1988), inter- and intraspecific competition (Orians 1980), and the thermal environment (Walsberg 1985). To understand habitat selection and the effect of such factors, patterns of nest habitat use must first be documented. For wild turkeys (Meleagris gallopavo), several investigators have recently reported quantitative data on nest habitat use (Lazarus and Porter 1985, Ransom et al. 1987, Wertz and Flake 1988). The variable habitats used for nesting and low sample sizes of these studies precluded elucidation of what criteria wild turkeys may use in choosing nest sites. Nest predation has been implicated by many investigators as a major limiting factor of wild turkey populations (Reagan and Morgan 1980, Speake 1980, Ransom et al. 1987), but the influence of predation on habitat choice is not clear. The objective of my study was to quantitatively document nest habitat use of an introduced population of Rio Grande wild turkeys (M. g. intermedia). I investigated nest site selection by (1) comparing nest sites to random sites at several levels, or scales, and (2) comparing the chronology and success of nests in different vegetative types. �214 STUDY AREA The study was conducted along the South Platte River in Logan, Morgan, and Washington counties in northeast Colorado. This riverbottom community extended to 1.0 km in width and was dominated by an open-canopied plains cottonwood (Populus sargentii) forest. Boxelder maple (Acer negundo), red ash (Fraxinus pennsylvanica), and Russian-olive (Eleagnus augustifolia) occurred in low but increasing frequencies. Common forbs included pepperweed or tall whitetop (Lepidium latifolium), poison hemlock (Conium maculatum), ragweed (Ambrosia spp.), sunflower (Helianthus spp.), and thistle (Cirsium spp.). Common grasses included cheatgrass brome (Bromus tectorum), prairie cordgrass (Spartina pectinata), inland saltgrass (Distichlis stricta), sand drop seed (Sporobolus cryptandrus), and wheatgrass (Agropyron spp.). Shrubs occurred in discrete patches and were predominately western snowberry (Symphoricarpos occidental is), although willows (Salix spp.) were common in mesic areas (plant names follow Scott and Wasser [1980]). Lindauer (1983) provided a complete vegetative description of this particular community. Private lands adjacent to the riverbottom were primarily used for production of alfalfa, corn, wheat, and other small grains and row crops. Cattle were grazed at varying intensities both in and adjacent to the riverbottom. The Colorado Division of Wildlife owned approximately one-third of the riverbottom in the study area. These lands were not grazed and were used for both consumptive and nonconsumptive recreation. Sixty Rio Grande wild turkeys from Kansas and Texas were introduced to the study area during 1980-83. previously existed in northeast Colorado. No wild turkeys had �215 METHODS Wild turkeys were trapped in February 1986-87 with drop-nets and clover traps. Captured birds were classified to age and sex and fitted with aluminum leg bands. Wild turkeys were classified as yearlings « 1 year of age) or adults (> 1 year of age) based on characteristics of P IX and X (Petrides 1942). Females were fitted with transmitters mounted on ponchos (Amstrup 1980) or attached to the central pair of retrices (Bray and Corner 1972). Poncho and tail-clip transmitters weighed 29-32 and 26-29 g, respectively, and had expected battery lives of 6 months. Habitat Measurements Hens were monitored daily, when possible, to ascertain nest initiation. Date of initiation was estimated by calculating the number of eggs laid and the incubation period (Chapter 1). Habitat variables were measured at both nest and random plots to document patterns of nest habitat use. Nest habitat variables were measured within 2 days after eggs hatched or were abandoned or depredated. Measurements of random habitat plots were distributed over the same periods as measurements of nest plots to minimize phenological bias. Eight nest plots and 31 associated random plots from 1986 were remeasured in April 1987 at the approximate time of nest initiation the previous year. All plots were 0.04-ha circles with 22.5-m diameters. Nest plots were centered on nest sites. Two types of random plots were established: adjacent random (AR) and study area random (SAR) plots. Up to 4 AR plots were associated with each nest. These plots were in random distances and directions from the nest with the constraint that they be within 79 m. Thus, in addition to the nest plot, an approximately 2-ha area was sampled around each nest. Study area �216 random plots were spaced at 2.5-km intervals throughout the linear study area. At each interval, SAR plots were established in the riverbottom at a random percentage of the riverbottom's width from the river at that interval. No SAR plots were within 300 m of a nest. Variables measured at nest and random plots were: canopy cover (overstory), understory cover, understory height, amount of shrubs, forbs, grasses, and bare ground, distance to nearest tree> 30 cm in diameter at breast height (DBH), and basal area of all trees and small « 25 cm DBH), medium (~ 25 and < 45 cm DBH), and large (~ 45 cm DBH) trees. Canopy cover was measured with a densiometer. A vegetation profile board (Nudds 1977) was used to estimate percent understory cover to 1 of 6 classes « and> 2.5, 2.5 - 25, 26 - 50, 51 - 75, 76 - 95, 95%) in each of 3 height categories « 0.5, 0.5 2.0 m). 1.0, and 1.1 The profile board was placed at the plot center and read from the plot perimeter in the 4 cardinal directions. Understory height was measured at these 4 perimeter locations and the plot center. Both understory height and basal area were measured in 5 cm classes. Meters of shrubs, forbs, grasses, and ground were estimated along 2 perpendicular, but randomly oriented, transects, each equal to the plot diameter of 22.5 m. In 1987, egg visibility was measured concurrent with habitat measurements at all 22 nests of radio-marked hens. Ten wild turkey eggs were placed in the nest bowl and number of visible eggs counted while standing above the nest, and while standing and crouching 2 and 5 m away in the 4 cardinal directions. were then averaged. The 4 directional measurements �217 Statistical Analyses Habitat measurements at AR plots for each nest site were averaged and these values then paired with associated nest plot data for analysis with Wilcoxon signed ranks tests. If < 2 AR plots were measured at a nest site, then the nest and associated AR plots were excluded from this analysis. Likewise, the 8 nests measured in April 1987 were paired with 1986 habitat data and analyzed with Wilcoxon signed ranks tests. Habitat differences between nest and SAR plots were tested with median tests because the distributional differences between these 2 groups prevented analysis with more powerful MannWhitney tests (Conover 1980). Habitat and egg visibility differences between nests of different age hens, fates (successful vs. unsuccessful), and vegetation types (snowberry vs. other) were tested with Mann-Whitney tests as were differences between AR and SAR plots. Nesting in snowberry vs. other vegetation as a function of nest initiation date was examined with logistic regression. Wilcoxon signed ranks tests were conducted using SPSS (Norusis 1986). The Statistical Analysis System was used for all other analyses (SAS Inst. Inc. 1987). RESULTS Thirty radio-marked hens initiated a known total of 35 nests. Thirty nests were in ungrazed"riverbottom, 3 nests were in riverbottom lightly grazed within the last year, and the 2 latest initiated nests (> 1 1/2 months after median nest initiation date [Chapter 1]) were approximately 200 m from the riverbottom edge in currently grazed pastures. Three hens were known to renest once and 1 hen twice. Excluding the hen that renested after laying a single egg, all 4 renests were in the opposite vegetation type (snowberry vs. other) from �218 the hens' previous attempts. Early nesting hens were more likely to nest in snowberry than late nesting hens (£ = 0.028) (Fig. 2.1). Nest plots measured at hatch (late May - Jun) had greater canopy and understory cover in all 3 height classes than the same nests measured at nest initiation (mid-Apr) the following year (£ < 0.05 for all tests). initiation Height of live grasses and forbs was much less at nest (X = 9, SE = 1) than at hatch (X = 56, SE = 3, £ < 0.001), but height of live shrubs did not vary between nest initiation 100, SE = 8) and hatch (X = 106, SE = 9, £ = 0.722). (X = Adjacent random plots also had greater canopy and understory (~ 1 m) cover at hatch than at nest initiation (£ < 0.05 for all tests). Thirty-one nests (includes 1 nest of an unmarked adult) were compared with their averaged AR plots. Nests were characterized by greater canopy cover, more shrubs, fewer grasses, and greater understory cover (~ 1 m) and height than AR plots (£ < 0.01 for all tests) (Table 2.1). Distance to large tree, basal area of trees, amount of forbs and bare ground, and understory cover> differ (£ > 0.05) between nest and AR plots. 1 m did not Comparing all 36 nests (including 1 nest of an unmarked adult) to SAR plots (n = 36), the same differences were found except that canopy cover and grass abundance did not differ. All significant differences were stronger than those between nest and AR plots. Additionally, AR plots had greater understory cover (> 0.5 and ~ 1.0 m) and height, more shrubs, and fewer large trees than SAR plots (£ < 0.05). Understory cover ~ 0.5 m also tended to be greater at AR plots (£ = 0.068). Other habitat variables did not differ between these 2 types of random plots (£ > 0.10). Nests in snowberry (n = 24) were characterized by significantly greater canopy cover, more large trees, being closer to a large tree, �>a: a: w co S 0 z (f) z CJ ._ z 0.9 0.80.7 -- - -, <, - -- .•...•. z LL 0 ._>- <, <, <, 0=36 P=0.028 <, <, <, <, •••.•...•..•.. <, <, <, <, <, <, <, <, <, ................ 0.6 <, 0.5 <, <, ~ CO 0 a: n, <, <, <, <, <, <, <, <, <, " <, -, 0.4 •..... <, 0.3 <, <, <, <, -, <, <, <, <, <, <, <, <, <, 0.2 _J co <, <, (f) w ...•.. 0.1 <, <, <, <, <, ....••. <, <, - .•...•. 0 1-----~------r-----r__--~----~------~----~----~~ 10 20 30 10 20 30 30 20 10 APR MAY JUN Fig. 2.1. Probability of wild turkeys nesting in snowberry as a function of nest initiation date in northeast Colorado, 1986-87. Regression predicted values ± SE from y = O.0414X - 6.0542, where initiation date was the Julian date. N f-' '0 �220 Table 2.1. Habitat variables at wild turkey nest and random plots in northeast Colorado, 1986-87. Nest Variable Canopy, % Shrubs, m Forbs, m Grasses, m Ground, m Understory cover, % < 0.5 m 0.5 - 1.0 m 1.1 - 2.0 m Understory height, cm Plot center Total plot Distance to large tree, m Basal area, m2/ha Small trees Medium trees Large trees Total trees Adjacent random (0._= 31) X SE Study area random (0._= 36) X SE 33.3 6.6 6.4 8.6 0.5 6.1 1.0 1.0 0.9 0.2 14.9 2.5 5.8 12.4 1.3 2.5* 0.5* 0.7 0.7* 0.3* 29.8 2.2 4.6 11.9 3.3 5.9 0.7+# 0.8 1.1 0.7+ 97 60 8 < 1 5 2 68 30 4* 4* 51 23 6+ 4+# - 6 1 11 2 94 70 6 4 57 54 4* 3* 36 41 5+# 3+# 24.7 7.6 0.7 2.8 6.3 9.9 0.3 0.9 1.9 2.1 27.5 6.9 0.3 1.8 3.5 5.6 0.1 0.5 0.6 0.8 25.1 5.7 0.8 2.1 0.5 3.7 1.3# 7.9 1.6 2.2 a Five additional nests included for statistical comparison to SAR plots. * £ < 0.05 for nest vs. AR plots. + £ < 0.05 for nest vs. SAR plots. # £ < 0.05 for AR vs. SAR plots. �221 more shrubs, and fewer forbs than nests in other vegetation (Table 2.2). Many snowberry clumps contained 1-5 large cottonwoods resulting in many of these differences. Nest failure due to predation was independent of habitat type (snowberry vs. other) when examined across entire seasons (~ test, ~ = 0.502, £ = 0.479). After splitting the data set into early (n =17) and late (n = 16) seasons and excluding 3 abandonments, early nests in snowberry tended to be more successful than late nests in snowberry, but this difference was not significant (Table 2.3). A greater proportion of nests in 1986 (11 of 13) were in snowberry than in 1987 (13 of 23). Nests in 1986 had greater understory cover (> 0.5 and ~ 1.0 m) than nests in 1987 (£ = 0.041) but did not differ for any other habitat variables. Nests of adult hens (n = 14) did not differ from those of yearlings (n = 22) nor did successful nests (n = 18) differ from unsuccessful nests (n = 16, 2 observer-induced abandonments excluded) for any of the measured nest habitat variables (£ > 0.05). Egg visibility from all angles did not differ between age classes, nest fates, or vegetation types. An average of 5.4 eggs was visible from above the nest, < 3 eggs were visible from 2 m, and < 1 egg was visible from 5 m. DISCUSSION Whereas floristic composition at nest sites varies greatly across the wild turkey's geographic range, most investigators have observed similar structural patterns in nest site vegetation. Nests are characterized by concealment in dense herbaceous or woody vegetation, both around and above the nest (Williams et al. 1968, Lazarus and Porter 1985, Wertz and Flake 1988). Similarly, I found that nests of Rio Grande wild turkeys were in denser and taller understory vegetation �222 Table 2.2. Habitat variables at wild turkey nests in snowberry and other vegetation in northeast Colorado, 1986-87. Snowberry ell = 24) SE X Variable Canopy, % Shrubs, m Forbs, m Grasses, m Ground, m Understory cover, % < 0.5 m 0.5 - 1.0 m 1.1 - 2.0 m Understory height, cm Plot center Total plot Distance to large tree, m Basal area, m2/ha Small trees Medium trees Large trees Total trees * £ < 0.05. Other 12) SE X (U = 40.2 9.3 4.4 7.9 0.4 7.2 1.0 0.9 1.2 0.2 14.1 0.5 10.6 10.6 0.5 7.2* 0.3* 1.8* 1.8 0.2 97 62 7 < 1 5 1 94 51 8 2 2 3 92 70 6 5 97 60 9 10 11.5 2.2 59.5 19.4* 0.9 3.3 8.6 12.8 0.4 1.1 2.3 2.5 0.1 0.8 0.5 1.3 0.1* 0.5 0.5* 1.0* �223 Table 2.3. Numbers of successful and depredated wild turkey nests in snowberry and mixed forbs and grasses in early and late season in northeast Colorado, 1986-87. Vegetation Season Fate Early Successful 9 1 Depredated 4 2 Successful 2 6 Depredated 6 3 Late Snowberry Forbs and grasses �224 than the surrounding environment. Low egg visibility and observation of incubating hens substantiated the concealing effect of these understory characteristics. Few nesting studies, however, have examined habitat use at multiple spatial and temporal scales. There is growing support that patterns and processes of habitat selection may differ among areal scales (Wiens 1985, Morris 1987, Martin and Roper 1988). In one wild turkey study that attempted to discern such dissimilarities across scales, Lazarus and Porter (1985) observed no habitat differences between nest sites and surrounding O.5-ha areas. These areas were, however, different from random plots sampled throughout the study area. They suggested that hens may be cuing on O.5-ha locales and then choosing a suitable nest site within this area. In my study area, hens may use a hierarchial nest selection process similar to that discussed by Wiens (1985). At the broadest scale, these hens exhibited a strong preference for riverbottom habitat (94% of all nests) vs. adjoining agricultural uplands. The comparatively sparse vegetation at nest initiation and the high disturbance levels in these agricultural areas were obvious disadvantages of nesting in this habitat type. On a more restricted spatial scale, differences in understory characteristics between AR and SAR plots suggest that perhaps hens were cuing on areas ~ 2 ha before making specific nest site choices. All nests in the riverbottom were surrounded by ~ 2 ha of currently ungrazed, relatively undisturbed land. Use of ungrazed areas may be related to grazing impacts on vegetation. Using unreplicated plots, Crouch (1978) found that cover and height of shrubs, forbs, and grasses were significantly greater on ungrazed than grazed plots in this riverbottom community. �225 Once within a 2-ha area, nest site selection on an even finer scale is suggested by habitat differences between nest and AR plots. Because differences between SAR and AR plots, and AR and nest plots were similar, such differential scalar selection processes should perhaps be envisioned as occurring on a gradient rather than at discrete levels. Alternatively, selection at the 2-ha level may not occur at all, and differences between SAR and AR plots may simply be due to specific nest site selection (i.e., SAR - nest plot differe~ces) and a correlation between AR and nest sites due to their proximity. Implied in this discussion is that hens cue on vegetative structure in the habitat selection process. Confounding influences such as population density, philopatry, and interspecific competition were not addressed in this study. Density effects on habitat selection similar to the Fretwell - Lucas (1969) model do not seem likely. This model requires a threshold density before suboptimal habitats fill and intraspecific nest site competition in optimal habitat occurs. The density of wild turkeys in this study area (-250-300 birds along -140 km of riverbottom in Jan 1987, T. Davis pers. commun.) was much lower than population estimates from other areas (Porter and Ludwig 1980, Hayden 1985, Kimmel and Kurzejeski 1985) and likely below a threshold density. Additionally, what a hen perceives as optimal habitat may change during a season. In mid April, when hens were first initiating nests, the amount of cover provided by snowberry was much greater than that provided by herbaceous vegetation, and thus, was probably more effective at deterring nest predators (Bowman and Harris 1980). As the season progressed, the cover value of forbs and grasses came closer to that of snowberry, and correspondingly, their use as nesting cover increased. �226 If indeed snowberry is more predator safe than mixed forbs and grasses in early season and less so in late season, as suggested by this study, then differential nesting success across seasons and between vegetation types would be expected. Direct interspecific competition with other ground nesting species is likely unimportant as the large body size of wild turkeys would be a great advantage in any aggressive encounter. However, parasitism of wild turkey nests by ring-necked pheasants (Phasianus colchicus) has been observed in this study area (Schmutz 1988). Indirect competition may occur through its effect on nest predation levels. Woody shrubs, primarily snowberry, were less abundant than mixed forbs and grasses, the other major vegetative type used for nesting by wild turkeys. Other species commonly nesting in snowberry were ring-necked pheasants, mallards (Anas platyrhynchos), red-winged blackbirds (Agelaius phoeniceus), and brown thrashers (Toxostoma rufum) (pers. observ.). If a greater density of birds' nests occurred in snowberry than the mixed forbs and grasses, then generalist nest predators would be expected to search these habitats with greater intensity. Additionally, if mixed forbs and grasses offered adequate cover, their greater abundances than shrubs would result in lower probabilities of nest predation in these habitats due to the increased amount of area (potential nest sites) a predator would need to search (Martin and Roper 1988). Therefore, hens may nest in snowberry early in the season because of the substantially greater cover offered by these woody shrubs. Later in the season when mixed forbs and grasses offer equivalent cover, hens may prefer this habitat type because of reduced predation. The observation that all renests after nest depredation occurred in the opposite vegetation type is further support that probability of �227 nest predation influences habitat selection in these wild turkeys. Changing habitat use in response to nest predation has also been observed in other ground nesting species (Storaas and Wegge 1987). Tall, dense understory vegetation, because of its moderation of nest predation, may be the primary cue by which wild turkeys select nesting habitat. LITERATURE CITED Amstrup, S. C. 1980. A radio-collar for game birds. Manage. 44:214-217. J. Wildl. Bowman, G. B., and L. D. Harris. 1980. Effect of spatial heterogeneity on ground-nest depredation. J. Wildl. Manage. 44:806-813. Bray, O. E., and G. W. Corner. 1972. A tail clip for attaching transmitters to birds. J. Wildl. Manage. 36:640-642. Conover, W. J. 1980. Practical nonparametric statistics. John Wiley & Sons, New York, N.Y. 493pp. Second ed. Crouch, G. L. 1978. Effect of protection from livestock on bottomland wildlife habitat in northeastern Colorado. Pages 118-125 in W. D. Graul and S. J. Bissell, tech. coords. Lowland river and stream habitat in Colorado: a symposium. Colorado Chap. The Wildl. Soc. and Colorado Audubon Counc., Greeley. Fretwell, S. D., and H. L. Lucas. 1969. On territorial behavior and' other factors influencing habitat distribution in birds. I. theoretical development. Acta Biotheor. 19:16-36. Hayden, A. H. 1985. Summer baiting as an indicator of wild turkey population trends and harvest. Proc. Natl. Wild Turkey Symp. 5:245-252. Kimmel, V. L., and E. W. Kurzejeski. 1985. Illegal hen kill - a major turkey mortality factor. Proc. Natl. Wild Turkey Symp. 5:55-65. Lazarus, J. E., and W. F. Porter. 1985. Nest habitat selection by wild turkeys in Minnesota. Proc. Natl. Wild Turkey Symp. 5:67-81. Lindauer, I. E. 1983. A comparison of the plant communities of the South Platte and Arkansas River drainages in eastern Colorado. Southwest. Nat. 28:249-259. Martin, T. E., and J. J. Roper. 1988. Nest predation and nest-site selection of a western population of the hermit thrush. Condor 90:51-57. �228 Morris, D. W. 1987. Ecological scale and habitat use. Ecology 68:362-369. Norusis, M. J. 1986. SPSS/PC+ for the IBM PC/XT/AT. Chicago, Ill. 643pp. SPSS Inc., Nudds, T. D. 1977. Quantifying the vegetative structure of wildlife cover. Wildl. Soc. Bull. 5:113-117. Orians, G. H. 1980. Some adaptations of marsh nesting blackbirds. Princeton Univ. Press, Princeton, N.J. Petrides, G. A. 1942. Age determination in American gallinaceous game birds. Trans. North Am. Wildl. Conf. 7:308-328. Porter, W. F., and J. R. Ludwig. 1980. Use of gobbling counts to monitor the distribution and abundance of wild turkeys. Proc. Natl. Wild Turkey Symp. 4:61-68. Ransom, D., Jr., O. J. Rongstad, and D. H. Rusch. 1987. Nesting ecology of Rio Grande turkeys. J. Wildl. Manage. 51:435-439. Reagan, J. M., and K. D. Morgan. 1980. Reproductive potential of Rio Grande turkey hens in the Edwards Plateau of Texas. Proc. Natl. Wild Turkey Symp. 4:136-144. SAS Institute Inc. 1987. SAS/STAT guide for personal computers, version 6 edition. Cary, N.C. 1028pp. Schmutz, J. A. 1988. Ring-necked pheasant parasitism of wild turkey nests. Wilson Bull. 100:In Press. Scott, T. G., and C. H. Wasser. 1980. Checklist of North American plants for wildlife biologists. The Wildl. Soc., Washington, D.C. 58pp. Speake, D. W. 1980. Predation on wild turkeys in Alabama. Natl. Wild Turkey Symp. 4:86-101. Proc. Storaas, T., and P. Wegge. 1987. Nesting habitats and nest predation in sympatric populations of capercaillie and black grouse. J. Wildl. Manage. 51:167-172. Walsberg, G. E. 1985. Physiological consequences of microhabitat selection. Pages 389-413 in M. L. Cody, ed. Habitat selection in birds. Academic Press, Inc. Orlando, Fla. Wertz, T. L., and L. D. Flake. 1988. Wild turkey nesting ecology in south central South Dakota. Prairie Nat. 20:29-37. Wiens, J. A. 1985. Habitat selection in variable environments: shrub-steppe birds. Pages 227-251 in M. L. Cody, ed. Habitat selection in birds. Academic Press, Inc. Orlando, Fla. Williams, L. L, Jr., D. H. Austin, N. F. Eicholz, T. E. Peoples, and R. W. Phillips. 1968. A study of nesting turkeys in southern Florida. Proc. Southeast. Assoc. Game and Fish Comm. 22:16-30. �229 Chapter 3 BROOD HABITAT USE OF RIO GRANDE WILD TURKEYS Many investigators have observed high use of clearings by wild turkey (Meleagris gallopavo) broods. These clearings included agricultural fields (Porter 1980), pastures (Everett et al. 1980), and old fields (Metzler and Speake 1985). Others have reported high use of woodlands and forests by broods (McCabe and Flake 1985, Mackey 1986). In particular, the importance of agricultural habitats is not clear. Whereas McCabe and Flake (1985) found little or no use of grasslands and nearby agricultural areas, Porter (1980) found that wild turkeys in Minnesota spent 45% of their diurnal activity in agricultural fields, particularly corn and alfalfa. Understanding brood habitat needs is vital for effective wild turkey management. The quality of brood habitat may affect brood survival (Metzler and Speake 1985), which can be quite low, and may affect wild turkey population dynamics (Everett et al. 1980, Speake et al. 1985). Habitat data on Rio Grande wild turkey broods (M. g. intermedia) are scant compared to other subspecies of wild turkeys. Although work has recently been conducted on Rio Grande wild turkeys in south Texas, poor nesting success limited data on brood habitat use (Ransom et al. 1987). I documented patterns of brood habitat use in an introduced population of Rio Grande wild turkeys in a Colorado riverbottom community bounded by intensive agriculture. �230 STUDY AREA The study was conducted along the South Platte River in Logan, Morgan, and Washington counties in northeast Colorado. This riverbottom community extended to 1.0 km in width and was dominated by an open-canopied plains cottonwood (Populus sargentii) forest. Boxelder maple (Acer negundo), red ash (Fraxinus pennsvlvanica), and Russian-olive (Eleagnus augustifolia) occurred in low but increasing frequencies. Common forbs included pepperweed or tall whitetop (Lepidium latifolium), poison hemlock (Conium maculatum), ragweed (Ambrosia spp.), sunflower (Helianthus spp.), and thistle (Cirsium spp.). Common grasses included cheatgrass brome (Bromus tectorum), prairie cordgrass (Spartina pectinata), inland saltgrass (Distichlis stricta), sand dropseed (Sporobolus cryptandrus), and wheatgrass (Agropyron spp.). Shrubs occurred in discrete patches and were predominately western snowberry (Symphoricarpos occidentalis), although willows (Salix spp.) were common in mesic areas (plant names follow Scott and Wasser [1980]). Lindauer (1983) provided a complete vegetative description of this particular community. Private lands adjacent to the riverbottom were primarily used for production of alfalfa, corn, wheat, and other small grains and row crops. Cattle were grazed at-varying intensities both in and adjacent to the riverbottom. The Colorado Division of Wildlife owned approximately one-third of the riverbottom in the study area. These lands were not grazed and were used for both consumptive and nonconsumptive recreation. Sixty Rio Grande wild turkeys from Kansas and Texas were introduced to the study area during 1980-83. previously existed in northeast Colorado. No wild turkeys had �231 METHODS Wild turkeys were trapped in February 1986-87 with drop-nets and clover traps. Captured birds were classified to age and sex and fitted with aluminum leg bands. Wild turkeys were classified as yearlings « 1 year of age) or adults (> 1 year of age) based on characteristics of P IX and X (Petrides 1942). Females were fitted with transmitters mounted on ponchos (Amstrup 1980) or attached to the central pair of retrices (Bray and Corner 1972). Poncho and tail-clip transmitters weighed 29-32 and 26-29 g, respectively, and had expected battery lives of 6 months. Wild turkey nests were located with biotelemetry and monitored daily, when possible, to ascertain hatching date. A hand-held Vagi antenna and receiver were used to locate broods to 1 of 3 precision levels: (1) visual location, (2) approaching brood hens to within 100 m, but without flushing, to estimate location coordinates, or (3) approaching only close enough to determine if the brood hen was in the riverbottom, adjacent agricultural areas, or the edge between these habitats. Macrohabitat use was examined by comparing frequencies of all locations across all habitat types, i.e., riverbottom, agricultural uplands, and edge. Edge was defined as being within 30 m of the discrete treeline that bounded the riverbottom. was also noted. Occurrence of grazing Individual broods were not located more than once per day with locations rotated among 3 diurnal periods of equal duration and starting 1/2 hour after sunrise and ending 1/2 hour before sunset. Multiple radio-marked hens in brood aggregations were counted as single data points except for measurement of nest to brood location distances. �232 Macrohabitat frequency data were analyzed with likelihood ratio tests (~ tests) (Sokal and Rohlf 1981:695-697). Microhabitat use was examined at 0.04-ha plots centered on visual locations in the riverbottom. Habitat variables measured at these plots were compared to 0.04-ha plots located randomly within the riverbottom but spaced systematically at 2.5 km intervals across the study area. Visual locations were not used for microhabitat analyses if location bias resulting from observer induced brood movement wa~ suspected. Collection of microhabitat data ceased when broods were 6 weeks old as location bias markedly increased at this age. Individual broods were not flushed more than once every 3 days. Variables measured at microhabitat plots were: canopy cover, understory cover, understory height, frequency of shrubs, forbs, grasses, and bare ground, distance to nearest tree> 30 cm in diameter at breast height (DBH), and basal area of all trees and small « 25 cm DBH), medium (~ 25 and < 45 cm DBH), and large (~ 45 cm DBH) trees. Canopy cover was measured with a densiometer. A vegetation profile board (Nudds 1977) was used to estimate percent cover to 1 of 6 classes « 2.5, 2.5 - 25, 26 - 50, 51 - 75, 76 - 95, and> 95%) in each of 3 height categories « 0.5, 0.5 - 1.0, and 1.1 - 2.0 m). The profile board was placed at the plot center and read from the plot perimeter in the 4 cardinal directions. Understory height was measured at these 4 perimeter locations and the plot center. Both understory height and basal area were measured in 5 cm classes. Meters of shrubs, forbs, grasses, and ground were estimated along 2 perpendicular, but randomly oriented, transects, each equal to the plot diameter of 22.5 m. Differential brood microhabitat use by brood age (young, < 22 days of age; old, ~ 22 days of age) was tested with I-way analysis of �233 variance of the ranked data with time of season blocked (Friedman test, Conover 1981:299). Locations prior to 1 July were classified as early season and all others as late season. Differential brood microhabitat use by time of season with brood age blocked was also tested as was young brood habitat vs. random habitat with time of season blocked. The Statistical Analysis System was used for all analyses (SAS Inst. Inc. 1987). RESULTS Macrohabitat Use Six broods in 1986 and 8 broods in 1987 were located 191 times. Seventy-eight percent of these 191 locations were in the riverbottom, 11% in agricultural uplands, and 11% on the edge between these 2 habitats. This distribution of locations was not constant throughout the day = 11.23, (§ £ = 0.024). Edge habitat was used more than expected in the evening, and agricultural uplands were used less then expected in the afternoon but more than expected in the morning. The contribution of each of these 3 use patterns to the overall § statistic was> 1.70. Use of the 3 habitat types was independent of brood age (£ = 0.228) but was mildly dependent on time of season (£ = 0.077). Agricultural habitats were used less than expected in early season but more than expected in late season. 1057 and her brood. This result was largely due to hen Eggs of this hen hatched on 21 July, approximately 1 1/2 months after the median hatch date (Chapter 1). of this brood's locations were in an alfalfa field. broods located> Eighty percent Of the 7 other 10 times, the next highest use of agricultural habitats was 15%, primarily pastures and old fields. Twenty-seven percent of all locations were on lands that were currently grazed or had visible signs of recent grazing. Grazing �234 intensity was not evaluated, but approximately 30-60% of the riverbottom was grazed. Within the riverbottom, broods used grazed areas more late in the season (£ < 0.001) and when they were older (£ < 0.001). Time of season and brood age were undoubtedly correlated. All 17 broods that hatched in the riverbottom were from nests in thickly vegetated, ungrazed land (Chapter 2). Hens with young broods stayed (X = within 1/2 km of their nest 451 m, SE = 106 m). At about 3 weeks of age many broods made movements to or across grazed areas. Ten brood hens each located> 10 times moved an average of 1,024 m (SE = 366 m) from their nest site to the geometric center of their older brood range. Microhabitat Use Forty-seven locations were obtained from 14 broods, each located 1-9 times. Young broods used habitat with fewer large trees (£ = 0.047) but more shrubs (£ = 0.030) and grasses (£ = 0.040) than older broods, irrespective of time of season. habitats with more shrubs (£ = 0.054) than late season broods. Early season broods used 0.021) and closer to large trees (£ = The limitations of ranked data analysis prohibited examination of a brood age - time of season interaction. Grasses were more abundant on young brood-use (n = 28) than random plots (n = 36, £= 0.035), but all other habitat variables did not differ between plots (£ > 0.10) (Table 3.1). DISCUSSION Daily activity patterns have not been quantitatively documented for wild turkey broods except with human-imprinted poults (e.g., Healy et al. 1975). In the wild turkey population I studied, brood habitat use varied with time of day. The low use of agricultural habitats in the afternoon may have been associated with high temperatures (daily �235 Table 3.1. Microhabitat variables at wild turkey brood-use « 22 days old) and random plots in early and late season in northeast Colorado, 1986-87. Random Brood Early (n = 25) SE X Variable Canopy, % Shrubs, m Forbs, m Grasses, m Ground, m Understory cover, < 0.5 m 0.5 - 1.0 m 1.1 - 2.0 m Understory height, cm Distance to large tree, m Basal area, m2/ha Small trees Medium trees Large trees Total trees * £ < 0.05. Late (n = 3) SE X Early (n_= 29) SE X Late 7) SE X tn = 22.2 0.8 4.0 14.5* 2.8 5.8 0.3 0.7 1.1 0.8 35.2 18.8 0.0 1.8 1.2 16.8 1.3 3.3 0.2 27.6 2.7 4.8 11.2 3.3 6.4 0.9 0.9 1.2 0.8 38.6 15.2 0.1 0.1 4.0 1.3 14.7 2.2 3.1 1.6 54 15 6 5 3 1 60 15 9 13 6 7 48 22 12 6 5 3 65 24 6 12 10 3 43 4 45 13 40 4 44 7 % 40.1 11.4 0.4 2.0 3.3 5.8 0.2 0.6 1.3 1.7 8.3 2.2 0.5 1.2 6.4 8.1 0.5 1.2 3.2 2.3 22.3 5.4 1.6 2.1 4.2 7.9 0.8 0.6 1.5 2.0 35.9 19.3 4.3 2.0 1.4 7.7 2.4 1.3 1.4 2.2 �236 maximum in Jul averaged 33 C). Assuming similarity to willow ptarmigan (Lagopus lagopus), young poults (~ 1 1/2 weeks of age) are not endothermic and thus highly susceptible to heat stress (Pedersen and Steen 1979). Because of their small size, relative to yearling and adult hens, even older poults may have difficulty maintaining thermoneutrality. Goldstein (1984) found that Gambel's quail (Callipepla gambelii) could only stay within the thermoneutral zone by staying inactive under shade from 1000 to 1600 hours. Also, warm temperatures may increase brood susceptibility to predation in open habitats. Red-tailed hawks (Buteo jamaicensis), abundant in the study area, soar and forage most often at temperatures between 28 and 35 C (Ballam 1984). Wild turkey poults switch from an invertebrate to primarily a vegetative diet at 2-4 weeks of age (Blackburn et al. 1975, Healy et al. 1975, Hurst and Stringer 1975). Changes in habitat use at this age have been attributed to this dietary switch (Williams et al. 1973, McCabe and Flake 1985). Healy (1985) reported that invertebrate abundance, poult feeding rate, and vegetation density were highly correlated. He suggested that life form, percent cover, and understory height could be used to predict adequate brood range. In this study, however, understory cover and-height did not differ between young and old brood-use sites. These lack of differences may have occurred because poults had not yet switched to a vegetative diet. Healy et al. (1975) did not observe this switch in human-imprinted poults until 5 weeks of age. Only 15% of the brood plots in my study were measured after this age. Vegetative life form differed between brood ages. Greater amounts of shrubs at young brood plots may have been associated with enhanced �237 protection from predators. Young poults are most susceptible to predation (Speake et al. 1985). Metzler and Speake (1985) observed differential survival of poults in relation to habitat. Additionally, structural complexity of vegetation has been shown to decrease avian predator efficiency (Temple 1987), particularly for snowberry (Sugden and Beyersbergen 1987), the most abundant woody shrub in the study area. Crouch (1978) studied the effects of grazing on vegetation in the South Platte riverbottom community. He found large differences in understory cover and height for shrubs, forbs, and grasses between an unreplicated grazed and ungrazed area. If grazed areas contain more preferred plant material then ungrazed areas, then increased used of grazed areas by older broods would be expected. Blackburn et al. (1975) found that pastures produced more inflorescences throughout the summer than 5 other habitat types sampled for poult forage availability in Alabama. Also, inflorescences in ungrazed areas may be too far off the ground for poults to obtain easily. Both dietary shift and reduced need for predator avoidance may result in higher use of grazed areas. Further research investigating proximate cues used by brood hens in selecting habitat is warranted. Heterogenous habitat use among individuals must be considered. Although numbers of locations were small, 1 brood hen (1057) exhibited distinctly different habitat use patterns than all other brood hens. Given such heterogeneity, habitat management for "average" habitat may not represent habitat used by any broods. Until fitness differences can be attributed to differential brood habitat use, management for single habitat types is not justified. �238 LITERATURE CITED Amstrup, S. C. 1980. A radio-collar for game birds. Manage. 44:214-217. J. Wildl. Ballam, J. M. 1984. The use of soaring by the red-tailed hawk (Buteo iamaicensis). Auk 101:519-524. Blackburn, W. E., J. P. Kirk, and J. E. Kennamer. 1975. Availability and utilization of summer foods by eastern wild turkey broods in Lee county, Alabama. Proc. Natl. Wild Turkey Symp. 3:86-96. Bray, O. E., and G. W. Corner. 1972. A tail clip for attaching transmitters to birds. J. Wildl. Manage. 36:640-642. Conover, W. J. 1980. Practical nonparametric statistics. John Wiley & Sons, New York, N.Y. 493pp. Second ed. Crouch, G. L. 1978. Effect of protection from livestock on bottomland wildlife habitat in northeastern Colorado. Pages 118-125 in W. D. Graul and S. J. Bissell, tech. coords. Lowland river and stream habitat in Colorado: a symposium. Colorado Chap. The Wildl. Soc. and Colorado Audubon Counc., Greeley. Everett, D. D., D. W. Speake, and W. K. Maddox. 1980. Natality and mortality of a north Alabama wild turkey population. Proc. Natl. Wild Turkey Symp. 4:117-126. Goldstein, D. L. 1984. The thermal environment and its constraint on activity of desert quail in summer. Auk 101:542-550. Healy, W. M. 1985. Turkey poult feeding activity, invertebrate abundance, and vegetation structure. J. Wildl. Manage. 49:466472. ______, R. O. Kimmel, and E. J. Goetz. 1975. Behavior of humanimprinted and hen-reared wild turkey poults. Proc. Natl. Wild Turkey Symp. 3:97-107. Hurst, G. A., and B. D. Stringer, Jr. 1975. Food habits of wild turkey poults in Mississippi. Proc. Natl. Wild Turkey Symp. 3:7685. Lindauer, I. E. 1983. A comparison of the plant communities of the South Platte and Arkansas River drainages in eastern Colorado. Southwest. Nat. 28:249-259. Mackey, D. L. 1986. Brood habitat of Merriam',s turkeys in southcentral Washington. Northwest Sci. 60:108-111. McCabe, K. F., and L. D. Flake. 1985. Brood rearing habitat use by wild turkey hens in southcentral South Dakota. Proc. Natl. Wild Turkey Symp. 5:121-131. Metzler, R., and D. W. Speake. 1985. Wild turkey poult mortality �239 rates and their relationship to brood habitat structure in northeast Alabama. Proc. Natl. Wild Turkey Symp. 5:103-111. Nudds, T. D. 1977. Quantifying the vegetative cover. Wildl. Soc. Bull. 5:113-117. structure of wildlife Pedersen, H. C., and J. B. Steen. 1979. Behavioral thermoregulation in willow ptarmigan chicks Lagopus lagopus. Ornis Scand. 10:1721. Petrides, G. A. 1942. Age determination in American gallinaceous birds. Trans. North Am. Wildl. Conf. 7:308-328. game Porter, W. F. 1980. An evaluation of wild turkey brood habitat in southeastern Minnesota. Proc Natl. Wild Turkey Symp. 4:203-212. Ransom, D., Jr., O. J. Rongst~d, and D. H. Rusch. 1987. Nesting ecology of Rio Grande turkeys. J. Wildl. Manage. 51:435-439. SAS Institute, Inc. 1987. SAS/STAT guide for personal computers, version 6 edition. Cary, N.C. 1028pp. Sakal, R. R., and F. J. Rohlf. 1981. Biometry. Freeman and Co., New York, N.Y. 859pp. Second ed. W. H. Scott, T. G., and C. H. Wasser. 1980. Checklist of North American plants for wildlife biologists. The Wildl. Soc., Washington, D.C. 58pp. Speake, D. W., R. Metzler, and J. McGlincy. 1985. Mortality of wild turkey poults in northern Alabama. J. Wildl. Manage. 49:472-474. Sugden, L. G., and G. W. Beyersbergen. 1987. Effect of nesting cover density on American crow predation of simulated duck nests. J. Wildl. Manage. 51:481-485. Temple, S. A. 1987. Do predators always capture substandard individuals disproportionately from prey populations. Ecology 68:669-674. Williams, L. E., Jr., D. H. Austin, T. E. Peoples, and R. W. Phillips. 1973. Observations on movement, behavior, and development of turkey broods. Pages 79-99 in G. C. Sanderson and H. C. Schultz, eds. Wild turkey management: current problems and programs. Univ. Missouri Press, Columbia. �240 Prepared by J"~ II .sG~;1"~ Joel A. Schmutz Approved by f!I~ f. ~ Clait E. Braun �241 JOB PROGRESS REPORT Colorado State of: Project: W-152-R Avian Research Job 9 Work Plan: 13 Job Title: Seasonal Habitat Use by Plains Sharp-tailed Grouse in Douglas County, COlorado Period Covered: Author: 01 January through 31 December 1987 Anthony Hoag Personnel: C. E. Braun, K. Demarest, J. Sarason, Colorado Division of wildlife; T. Hoag, E. Redente, Colorado State University ABSTRACT Plains sharp-tailed grouse (Tympanuchus phasianellus jamesii) movements and habitat were studied in Douglas County, Colorado during Harch-November 1987. Three leks were identified for trapping and radiomarking sharptails. Cherokee Lek had the highest peak count of sharptails visiting the lek with 13 while Dakin Lek had the highest peak count of hens (4) at one time. Sixteen sharptails were captured in walk-in traps and fitted with solar-powered radios. Spring movement data indicated the sharptails moved 2 km from Gambel oak (Quercus gambelii), and true mountainmahogany (Cercocarpus montanus) dominated areas to leks. Summer was the time of least movement with sharptails not moving outside a 2 km2 area. In fall sharptails moved into mountain mahogany and .o akbrush habitats. Home range was, on average, 15 km2 for the year. Habita_tmeasurements identified structural and vegetative components of sharp-tailed grouse use areaS. Canopy cover was highest at nests. Distance to clumps varied with nesting and non-nesting sharptails. The highest distance to cover, on average was 3.2 m,' Clump height, length, and width were highest at roosting sites in spring. ��243 SEASONAL HABITAT USE BY PLAINS SHARP-TAILED GROUSE IN DOUGLAS COUNTY, COLORADO Anthony Hoag INTRODUCTION Plains sharp-tailed grouse occupy suitable habitats from northeastern Colorado and western Nebraska into southern Canada (Aldrich 1963, Bailey and Niedrach 1965). The range of this subspecies has been greatly reduced along its southern periphery largely because former habitats have been altered by agricultural practices (Aldrich 1963, Miller and Graul 1980). Livestock grazing is a dominant land use in the remaining habitat of plains sharp-tailed grouse. Range management favoririg livestock has altered the mixture of grasses, forbs, and shrubs that sharptai1s use for cover (Sisson 1976). In Colorado, plains sharp-tailed grouse historically occupied suitable habitats east of the Front Range of the Rocky Mountains from Larimer County (Cooke 1897, Sc1ater 1912) south into E1 Paso County (Aiken and Warren 1914) and east to Kit Carson, Lincoln, and Yuma counties (Cooke 1897, Sc1ater 1912). Within this area, specimens are available in the Denver Huseum of Natural History from Arapahoe, Douglas, Elbert, and Yuma counties (Bailey and Niedrach 1965). This race of sharptai1s historically was apparently most abundant along the foothills in Larimer (Cooke 1897, Sclater 1912), Boulder (Henderson 1909), Douglas (Bailey and Niedrach 1965), and E1 Paso counties (Aiken and Warren 1914). llothCooke (1897) and Sc1ater (1912) reported that sharp-tailed grouse were not common in Colorado. Apparently, the species became uncommon between 1877 and 1887 (Cooke 1897). The plains race of sharptai1s (!. £. jamesii) was described from Colorado by Lincoln (1917) and this name was applied to all sharp-tailed grouse in eastern Colorado by Snyder (1939). Throughout the greater part of its range, sharp-tailed grouse are inhabitants of the ecotone between forest and prairie with woody vegetation in the form of shrubs and trees considered an essential component of its habitat (Grange 1948). Sclater (1912), Baumgartner (1939), Bailey and Niedrach (1965), Hillman and Jackson (1973), and Moyles (1981) reported sharptails used grassland and grassland-shrub transition zones throughout the year. In spring, courtship occurs on ridges and hills with short sparse vegetation (Baumgartner 1939, Douglas 1942, Kobriger 1965, Sisson 1976) at the center of the lek and escape cover within 200 m (Pepper 1972). When not on leks, hens and cocks feed or rest in ecotone edges (Baumgartner 1939). Schiller (1973) reported nests of sharptails in grassland, brush1and, and cropland. Artmann (1970) found extensive use of brush1and cover by nesting sharptails and Pepper (1972) found nests in native grass-shrub mixtures. Sharptail hens with broods usually select sites with some overhead cover nearby (Amman 1957) and in grassland interspersed with shrubs (Hamerstrom 1963, Bernhoft 1969, Pepper 1972, Schiller 1973, Sisson 1976, Kohn et al. 1982). Habitats used by sharptails during summer are dominated- by grass and shrubs (Aldous 1943, Hamerstrom and Hamerstrom 1951, Buss and Dziedzic 1955). �244 Moyles (1981) reported that sharptails use grassland or grassland-shrub communities during fall. These communities offer both food (insects and fruits) and roosting cover. In winters with snow, sharptails roost singly or singly in small flocks in snow beneath scattered trees (Baumgartner 1939, Hamerstrom and Hamerstrom 1951, Kirsch et ale 1973). In mild weather, flocks disperse and travel distances up to approximately 2 km (Hamerstrom and Hamerstrom 1951). Previous work on plains sharp-tailed grouse has provided valuable data for the subspecies in major areas of its range. However, data on the relict plains sharp-tailed grouse population in Colorado are limited (Stearns 1968). If this population is to be maintained in perpetuity, knowledge on how it presently survives in the remaining habitats is essential. The objectives of this study are to quantify seasonal habitat use and movements of plains sharp-tailed grouse in Douglas County, Colorado. Hypotheses HOI: H02: being tested are: No changes occur sites. changes among sharptail use Ha: Use site plant composition Hb: Vegetation at escape, nesting, brooding, feeding and loafing, and roosting sites has proportionately more shrubs than at random sites. seasonally. Plant physiognomy (canopy cover, plant height, clump distance, height, clump width, and clump length) does not differ between points or between use sites. Ha: H03: in plant species composition Nest, brood, feeding and loafing, and escape cover have greater canopy cover, plant height, clump height, clump width, clump length, and less distance to clumps than at random points or between use sites. Movements activity. Ha: clump random do not differ by age class, sex, season or biological Movements are greatest in spring and fall. P. N. OBJECTIVES The objectives of this study are to quantify seasonal habitat use and movements of plains sharp~tailed grouse in Douglas County, Colorado. �245 SEGMENT OBJECTIVES 1. Review literature relating to grouse, plains sharptails, habitat selection, movement, capture and marking techniques, and methods analyzing vegetation. trap, and radio mark 20 plains sharp-tailed for 2. Locate, 3. Quantify and compare use site vegetation with random point vegetation classified by season, activity, and sex and age of sharp-tailed grouse. 4. Quantify 5. Map the vegetation of the study site and identify used by plains sharp-tailed grouse. 6. Compile and analyze data and prepare aNnual report. daily and seasonal grouse on 4 leks. movement's of sharp-tailed grouse. the habitat components STUDY AREA The study area is in the foothills and tablelands of Douglas County, Colorado (Fig. 1). Elevation ranges from approximately 1,850 to 2,200 m. The climate is of the high inland continental type as modified by the Rocky Mountains and the Palmer Divide (U.S. Dep. Agric. 1974). General climatic characteristics include low precipitation, low humidity, variable winds, and a wide temperature range. The average annual precipitation is 37-44 cm. May is the wetest month receiving 16-20% of the annual moisture (U.S. Dep. Agric. 1974). Winter (Dec-Feb) is the driest period receiving only 8-9% of the annual moisture (U.S. Dep. Agric. 1974). Temperature ranges from -30 to 38 C with a mean annual temperature of 19 C (U.S. Dep. Agric. 1974). Upland areas are moderately rolling to broken tablelands dissected by tributaries of Plum and Cherry creeks. Soil parent materials vary widely. The primary parent materials are calcareous and arkosic fans and pedisediments; red arkose, sedimentary, and red sedimentary bedrock; and Eolian deposits. Soils are loam to clay in the western section and sandy to gravelly in the eastern section of the study site (U.S. Dep. Agric. 1974). Gambel's oak and true mountainmahogany are the dominant shrubs in upland areas. Fragrant sumac (Rhus aromatica) and rabbitbrush (Chrysothamnus spp.) are common understory shrubs. Understory forbs include Astragalus, Melilotus, uescurainia, and Yucca. Dominant grasses in upland areas include Bromus, Poa, Koeleria, and Agropyron. The primary land use is ranching, housing developments, and agriculture. METHODS Plains sharp-tailed grouse at 3 active leks were chosen for study in 1987. Walk-in traps with chicken wire leads connecting traps to direct sharptails into them were placed in the middle or at the periphery of the lek. Captured sharptails were fitted with solar-powered poncho-mounted radiQs (150-152 Mhz) (Amstrup 1980), serially-numbered aluminum leg bands, and plastic bandettes �N ..,.. 0'1 T6s NORTH I 7 8 • • KNOWN 9 ACTIVE LEKS DOCUMENTED BIRD PRESENCE 10 ~ 70 R71W Fig 1. 69 Plains sharp-tailed 68 67 grouse distribution 66 in Douglas 65 County, Colorado. STATUS UNKNOWN �247 color coded to designate lek of capture, sex, and age. Captured birds were classified to sex and age, and measurements were taken of weight, carpal length, and length of primary feathers I-X. In spring 1987, 12 males and 3 females were captured in walk-in traps (7 males and 1 female at Cherokee Lek, 2 males and 2 females at Dakin Lek, 3 males at Lincoln Mountain Lek). One male was captured using a spotlight and a long-handled net (Giesen et ale 1982) while roosting near the Dakin Lek. Radiolocations were obtained at leks, feeding and loafing, escape, roost, nest, and brood sites (activity sites) using a portable receiver and a 3-element Yagi antenna. Locations were determined by triangulation or by flushing the birds and plotted on 7.5-minute U.S. Geologic Survey topographic maps by season and activity. Size of study sites was delineated after movement data from the first year were available. Weather conditions, physiognomic features, general vegetation, and flock size were recorded at each site where birds were encountered. Vegetation measurements were taken separately for each biological activity and season. A polygon was drawn around concentrations (>2) of observations and the resulting areas were designated as use sites. A transect, started from a random point produced by a random number generator, was placed in each use polygon with vegetation measurements taken at 25-m intervals. If the edge of the transect was met before an adequate sample (Sokol and Rohlf 1981) was obtained, a second random transect was started. Each vegetation sample included canopy cover, highest plant height within 1 m of the random point, distance to clump cover (defined as any live or residual vegetation that could supply a sharp tail with at least 50% cover taken at one direction on a spherical densiometer), and height, width, and length of clump cover. Vegetation at random points and in clumps was identified following Harrington (1954). All measurements were taken once in each of the 4 cardinal directions from--the random point. Data analysis was by comparing means. RESULTS Trapping The most successful method used to trap plains sharp-tailed grouse was the walk-in trap. Twenty-five of 26 captured birds were caught in walk-in traps, while one was caught using a long-handled net and spotlight (9 of 26 captures were recaptures). The most effective set-up to direct sharptails into traps was 3 separate lines of traps placed in the center of the lek. Thirteen of 16 individuals captured were adult males with an average weight of 933 grams. Carpal length varied from 225 to 240 mm for males (x = 233 for adults, 225 for yearlings) and 210 to 222 mm for females. Average primary feather lengths ranged from III (PI, yearling males) to 168 mm (p VII & VIII, adult males) (Table 1). �248 Table 1. Measurements of plains sharp-tailed grouse in Douglas County, Colorado, 1987. Males Category Ad Yrlg Females Sample size Carpal length, mm Weight, <:>a Primary length, mm X IX VIII VII VI V IV III II I 11 233.2 933.2 3 225.0 886.7 3 217.0 775.0 128.8 154.8 168.0 168.0 166.0 161.0 137.0 126.0 120.0 113.0 124.0 145.0 162.0 162.0 159.0 147.0 131.0 123.0 113.0 111.0 122.0 147.0 160.0 162.0 163.0 155.0 135.0 123.0 117.0 112.0 The numbers of sharptails at each lek varied from a high of 11 males and 2 females at Cherokee to a low of 7 males and 0 females at Lincoln Mountain. The Dakin Lek had the most females on the lek at one time with 4 present for a 2-day period (2 were captured and fitted with radios). One possible reason more hens did not appear on the Cherokee Lek is that they were bypassing it for the Woodhouse Lek to the northwest. One radio-marked hen captured on the Cherokee Lek was found predated 2.4 km north of the Woodhouse Lek. Movements Radiotracking was used to identify the daily and seasonal movements and habitats of plains sharptails. The birds at Cherokee and Lincoln Mountain were initially found feeding, loafing, roosting, and escaping to tall dense oakbrush clumps (Tables 2, 3). Lek activity occurred in areas virtually devoid of vegetation. As the breeding period advanced, males stayed closer to leks selecting mountainmahogany for feeding, loafing, and escape cover. Roosting occurred on ridges with residual forb and grass cover that were near leks. Males spent most of the day on or near leks as the breeding period peaked, often displaying during 2-3 periods/day on the Cherokee Lek. When breeding ended, non-nesting sharptails moved to areas dominated by cool season grasses. Often birds were flushed from small dense clumps of cheatgrass (Bromus spp.) and flew to draws with mountainmahogany and oakbrush. Sharptails remained in habitats dominated by grasses throughout the summer and into the beginning of fall. As grasses senesced and began to lodge, sharptails moved into mountainmahogany and oakbrush habitats where they spent the fall (Tables 2, 3). �249 Table 2. Dominant plant species at sharp-tailed grouse use sites, 1987. Cherokee Lek Species % Spring (Mar-Hay) N = 38 Quercus gambelii Grasses Poa fendleriana KOeleria cristata Descurainia sophia Yucca glauca 0.440 0.237 0.158 0.078 0.0526 0.0263 Bromus spp. Poa fendleriana Symphoricarpos albus Cercocarpus montanus 0.788 0.091 0.091 0.031 Summer (Jun-Aug) N = 68 0.553 0.106 0.082 0.071 0.059 0.047 0.029 0.029 0.012 0.011 Fall (Sep-Nov) N = 36 Quercus gambelii Cercocarpus montanus Rhus aroma tica Poa fendleriana BrOmus spp , Yucca glauca % Spring (Mar-May) N = 33 Summer (Jun-Aug) N = 170 Bromus spp. Koeleria cristata Cercocarpus montanus Poa fendleriana YUCca glauca Quercus gambelii Stipa comata Helianthus spp. Astragalus drummondii Agropyron smithii Dakin Lek Species Poa fendleriana ChTysothamnus spp. Koeleria cristata Bromus spp. Forbs Cirsium spp. Quercus gambelii 0.309 0.206 0.191 0.118 0.103 0.044 0.029 Fall (Sep-Nov) N = 22 0.600 0.200 0.066 0.066 0.033 0.033 Bromus Stipa comata Lupinus spp. 0.550 0.275 0.131 �250 Table 3. Clump species at sharp-tailed grouse use sites, 1987. Cherokee Lek Species % Spring (Mar-May) N = 38 Quercus gambelii Yucca glauca Symphoricarpos albus Forbs 0.526 0.368 0.079 0.0263 Yucca glauca Cercocarpus montanus Symphoricarpos albus Forbs 0.510 0.358 0.091 0.062 Summer (Jun-Aug) N = 59 0.414 0.279 0.129 0.085 0.057 Chrysothamnus spp. Yucca glauca Cirsium spp. Forbs Lupinus spp. 0.356 0.288 0.186 0.119 0.033 Fall (Sep-Nov) N = 22 Fall (Sep-Nov) N = 36 Quercus gambelii Cercocarpus montanus Rhus aroma tica Yi.'iCCa glauca % Spring (Mar-May) N = 22 Summer (Jun-Aug) N = 140 Bromus spp. Yucca glauca Cercocarpus montanus Quercus gambelii Rhus aromatica Dakin Lek Species 0.600 0.300 0.066 0.033 Bromus spp. Stipa comata Lupinus spp. 0.550 0.275 0.181 Sharptail home ranges were calculated for m1n1mum convex and concave polygons and harmonic means transformation contours were drawn for each bird (Stuwe and Blohowisk 1985). Contours were calculated for 10, 25, 50, 75, 95, and 100% (Appendix). Home ranges at the Cherokee and Dakin sites increased significantly as the number of observations increased. Birds that survived the breeding season moved to summer habitats not included in spring locations leading to the increased size of the home range (Table 4). Home ranges of males were larger and more continuous than those of females. Hens moved considerable distances from leks to nest, and remained near the nesting site with their brood throughout the summer. Male sharp-tailed grouse remained within 1 km of the lek throughout summer and fall. �251 Table 4. Home range size estimates (ha) for plains sharp-tailed grouse in Douglas County, Colorado, 1987. Age Sex N· Convex polygon Concave polygon M M M M M M M 23 26 36 47 63 30 21 102.04 82.20 105.76 162.99 207.20 144.14 149.77 33.87 43.90 49.77 114.90 79.58 85.04 62.21 M M F F 18 26 13 47 46.20 50.25 132.60 179.96 18.00 34.63 1.90 10.58 Cherokee Ad Ad Ad Ad Ad Ad Yrlg Dakin Ad Yrlg Ad Ad During the breeding season male sharptails were not observed farther than 2 km from the lek. From June through September sharptails were sedentary, rarely moving outside a 2 km2 area. During October through November sharptails moved from grass/forb habitats used in summer into mountainmahogany and oakbrush habitats. Weekly radiolocations indicated sharptails moved through different oakbrush-dominated draws near the Cherokee Lek. Young produced near Dakin Lek separated from the hen in late August, but remained in the same valley as the hen throughout fall. HABITAT Habitat data showed wide variation in variables between activity sites, seasons, and general lek sites. The data from Cherokee Lek were based on 7 males in spring, 3 males in summer, and 2 males in fall. Data from Dakin were based on 3 males and 2 females in spring, and from 1 hen and 7 chicks in summer and fall. The 3 radio-marked males from Lincoln Mountain were predated before sufficient data had been collected. Seasonal Habitat Canopy cover was highest in areas used by the hen with chicks during summer. Cover at use sites in spring and fall for Dakin and Cherok~e leks was between 21 and 25%. Plant height was lowest for sharptai1s on leks and also at Cherokee Lek in summer where birds moved into habitats dominated by grasses (Bromus, Poa, Koeleria, and Agropyron). The spring and fall clump data reflected the dominance of mountain mahogany at Dakin Lek and oakbrush at Cherokee Lek. Clump distance was lowest for the hen and chicks near Dakin Lek during summer. All other clump distances were roughly equal for birds marked �252 at both leks for all seasons. Differences between clump width, length, and height were greatest between seasons with all 3 variables decreasing between spring and summer and increasing in fall (Table 5). Table 5. Seasonal habitat measurements at plains sharp-tailed grouse use sites, 1987. Spring Canopy cover, % Plant height, m Clump distance, m Clump width, m Clump length, m Clump height, m Summer Cherokee N_ = 110 Dakin N_ = 45 Cherokee N = 170 Dakin N_ = 60 25.2 0.816 2.55 4.15 3.99 1.19 25.0 0.722 3.66 '4.54 4.77 0.954 21.7 0.554 2.86 1.705 1.625 0.805 45.0 0.812 1.36 3.207 3.24 0.886 Activity Site Habitats Canopy cover was highest at feeding, loafing, and flushing sites (23%) and lowest for roosting sites at Cherokee Lek. Nesting canopy cover was highest near Dakin Lek (79%). Canopy cover at flush sites was lower than would have been predicted, but measurements were averaged over all flush areas including samples taken from shortgrass areas between clumps (Table 6). Plant height was highest for roosting sites at Cherokee Lek and feeding and loafing sites at Dakin Lek. Plant height averages were equal for all other activities (Table 6). Average distance to clumps was generally opposite for the Cherokee and Dakin leks. Distances were lowest for roosting at Cherokee Lek and highest at Dakin Lek. The highest distance to clump cover at Cherokee Lek was at flush sites. This was the second lowest distance at Dakin Lek (nesting was lowest distance to cover). For other activities, the furthest average distance to clump cover was 3.2 m (Table 6). Clump width, length, and height decreased from roosting sites to feeding and loafing sites, and to flush sites at both leks. A typical sharptail roosting site had greater plant height, clump height, width, and length, and less distance to clump cover than feeding, loafing, and flush sites. The average canopy cover (or plant density) at roosting sites was less than at all other activity sites except lek sites (Table 6). �253 Table 6. Characteristics of activity site habitat variables for plains sharp-tailed grouse, 1987. Characteristic Canopy cover Cherokee Dakin Roosting x N 19.44 28.6 33 34 Feeding and loafing x N 23.26 47.9 152 41 Flush x 23.1 40.1 Brood N 46 27 x 42.3 Nest N 50 x 71.5 Plant height Cherokee Dakin 0.829 0.694 0.590 0.767 0.597 0.7204 1.52 0.82 Clump distance Cherokee Dakin 1.303 3.2 2.95 1.28 2.87 0.903 1.54 0.00 Clump width Cherokee Dakin 4.44 4.27 1.85 2.98 1.50 2.71 2.85 15.25 Clump length Cherokee Dakin 4.37 4.56 1.66 2.86 1.64 2.23 3.04 12.29 Clump height Cherokee Dakin 1.33 0.91 0.86 0.814 0.79 0.856 0.825 0.82 N 2 �254 LITERATURE CITED Aiken, L. E. H., and E. R. Warren. 1914. The birds of El Paso County, Colorado. Colorado ColI. Sci. Series 12:455-603. Aldous, S. E. 1943. Sharp-tailed grouse in the sand dune country of north central North Dakota. J. Wildl. Manage. 7:23-31. Aldrich, J. W. 1963. Geographic orientation of American Tetraonidae. Wildl. Manage. 27:529-545. Amman, G. A. 1957. The prairie grouse of Michigan. Tech. Bull. 200pp. Amstrup, S. C. 215-216. 1980. A radio collar for game birds. J. Michigan Dep. Conserve J. Wildl. Manage. 44: Artmann, J. W. 1970. Spring and summer ecology of the sharptail grouse. Ph.D. Thesis, Univ. Minnesota, Minneapolis. l52pp. Bailey, A. M., and R. J. Niedrach. Mus. Nat. Hist., Denver, Colo. 1965. Birds of Colorado. 454pp. Vol. 1. Denver Baumgartner, F. M. 1939. Studies on the distribution and habits of the sharptail grouse in Michigan. Trans. Am. Wildl. Conf. 4:485-490. Bernhoft, L. S. 1969. Reproductive ecology of female sharp-tailed grouse (Pedioecetes phasianellus jamesii) and food habits of broods in southwestern North Dakota. M.S. Thesis, Univ. North Dakota, Grand Forks. 96 pp. Buss, I. 0., and E. S. Dziedzic. 1955. Relation of cultivation to the disappearance of the Columbian sharp-tailed grouse from south-eastern Washington. Condor 57:185-187. Cooke, W. W. l44pp. 1897. The birds of Colorado. Colorado Agric. ColI. Bull. 37. Douglas, D. W. 1942. A pralrle chicken booming grounds survey in central Michigan. Wilson Bull. 54:171-172. Giesen, K. M., T. J. Schoenberg, and C. E. Braun. 1982. Methods for trapping sage grouse in Colorado. Wildl. Soc. Bull. 10:224-231. Grange, W. B. 1948. Wisconsin grouse problems. Wisconsin Conserve Dep. Fed. Aid Wildl. Rest. Proj. 5R, Publ. 328. 3l8pp. Hamerstrom, F. N., Jr. 1963. Sharptail brood habitat in Wisconsin's northern pine barrens. J. Wildl. Manage. 27:792-802. _____ , and F. Hamerstrom. 1951. Mobility of the sharp-tailed grouse in relation to its ecology and distribution. Am. MidI. Nat. 46:174-226. �255 Harrington, H. D. Denver, Colo. 1954. Manual of the plants of Colorado. 666pp. Sage Books, Henderson, J. 1909. An annotated list of birds of Boulder County, Colorado. Univ. Colorado Studies 6:219-242. Hillman, C. N., and W. W. Jackson. 1973. The sharp-tailed grouse in South Dakota. South Dakota Dep. Game, Fish and Parks Tech. Bull. 3. 64pp. Kirsch, L. M., A. T. Klett, and H. W. Miller. 1973. grouse population relationships in North Dakota. 37:449-453. Land use and pralrle J. Wildl. Mange. Kobriger, G. D. 1965. Status, movements, habits, and foods of prairie grouse on a sandhills refuge. J. Wildl. Manage. 29:788-800. Kohn, S. C., R. L. Linder, and G. D. Kobriger. 1982. Sharp-tailed grouse nesting habitat in south-western North Dakota. Pages 166-164 in J. N. Peek and P. D. Dalke, eds., Proc. Wildlife-Livestock Relationships Symp. Univ. Idaho For., Wildl. and Range Expt. Stn., Moscow. Lincoln, F. C. 1917. A review of the genus Pedioecetes in Colorado. BioI. Soc. Washington 30:83-86. Proc. Miller, G. C., and W. D. Graul. 1980. Status of sharp-tailed grouse in North America. Pages 18-28 in P. A. Vohs, Jr., and F. L. Knopf, eds. Proc. Prairie Grouse Symp. Oklahoma State Univ., Stillwater. Moyles, D. L. J. 1981. Seasonal and daily use of plant communities by sharp-tailed grouse (Pedioecetes phasianellus) in the parklands of Alberta. Can. Field-Nat. 95:287-291. Pepper, G. W. 1972. The ecology of sharp-tailed grouse during spring and summer in the aspen parklands of Saskatchewan. Saskatchewan Dep. Nat. Resour. Wildl. Rep. 1. 56pp. Schiller, R. J. 1973. Reproductive ecology of female sharp-tailed grouse (Pedioecetes phasianellus) and its relationship to early plant succession in north-west Minnesota. Ph.D. Thesis, Univ. Minnesota, Minneapolis. l86pp. Sclater, W. H. 1912. A history of the birds of Colorado. London, U.K. 576pp. Sisson, L. 1976. The sharp-tailed grouse in Nebraska: Nebraska Game and Parks Comm., Lincoln. 88pp. Snyder, L. L. 1939. 56:184-185. Witherby and Co., a research study. Great plains races of sharp-tailed grouse. Sokal, R. R., and F. J. Rohlf. 1981. San Francisco, Calif. 859pp. Biometry. Auk W. H. Freeman and Co., �256 Stearns, F. D. 1968. Sharp-tailed grouse density in east-central Colorado related to selected habitat factors. M.S. Thesis, Colorado State Univ., Fort Collins. l33pp. Stuwe, M., and C. E. Blohowisk. 1985. Micro-computer analysis for animal locations. Conserve Res. Center, Natl. Zool. Park, Smithsonian lnst., Washington, D.C. 2lpp. u.S. Department of Agriculture. 1974. Soil Survey of Castle Rock area, Colorado. u.S. Dep. Agric., Soil Conserve Serv., Washington, D.C. ~~ Prepared by ~~~~~~~~~~~. - ~~~~~~/_. Anth~ ~ Graduate Research Assistant Approved by Clait E. Braun Wildlife Research Leader _ �257 APPENDIX �i r.---". ='~ I I··--~ 1 i ; '1 --J; 2 ) .-.-. ",'. ".'.I,. •• ' •••• I J •••• e-.'.'' ISI' !\ \ r ..- I I' 1 Ii ", e.; ..,....\ -G • .".J ~_ _~- l r= ~-=:,tl I . -eo •••. i .....' 258 .p' -c- // ~.~ J i' J! /', ~.:=: II i'~.. ¥. ;;;! .-__ I I.... ~ 1•• _. "1 , ~~I\i.. ~ ~J c: o ...~•. 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" w , 267 �r;:; ......,_.;. ,'::'"'1 ,-::.-- .'>.. :£ C:! 1,.:;''1 <..:;...c c: I"i"'; ;;:.. o ._ .:= o :..£ ~ ~ :::!::: 268 .• .: ----..:.~- .-----------~------..-.-~ �269 JOB PROGRESS REPORT State of: Project: Colorado Avian Research W-152-R Work Plan: 14 Job Title: Seasonal Movement and Habitat Use by Greater Prairie-Chickens Period Covered: Author: Job 3 ----- 01 January through 31 December 1987 Michael A. Schroeder Personnel: M. A. Schroeder and G. C. White, Colorado State University; C. E. Braun, J. F. Corey, F. Pusateri, and L. A. Robb, Colorado Division of Wildlife ABSTRACT Investigations were continued to examine seasonal movements and habitat use of greater prairie-chickens (Tympanuchus cupido) in northeastern Colorado. Preliminary results suggest that during the breeding season female prairie-chickens move throughout home ranges that often encompass 2 or more leks. Females nested an average of 2.86 km from the lek at which they were captured. Females also tended to have larger home ranges than males during most seasons. Although most males seemed to have site fidelity to a particular lek, some moved between 2 or more leks.· Habitat-use was variable within each season, and differences between observed and available habitat sites were generally unclear. Behavior (such as loafing, nesting, feeding) appeared to be more important than either sex or season for interpreting habitat use. ��271 SEASONAL MOVEMENT AND HABITAT USE BY GREATER PRAIRIE-CHICKENS Michael A. Schroeder P. N. OBJECTIVES 1. Quantify seasonal habitat use, movements, and lek attendance of greater prairie-chickens in northeastern Colorado. SEGMENT OBJECTIVES 1. Trap and mark as many greater prairie-chickens as possible in an area containing 8 to 10 leks. 2. Radiomark up to 50 (32 female and 18 male) greater prairie-chickens. 3. Relocate all radio-marked greater prairie-chickens at least 20 times per season (40 times during the late spring season, 1 Apr-15 May). 4. Analyze movement of greater prairie-chickens in relation to cover types as mapped on the entire study area. 5. Describe vegetation at all greater prairie-chicken relocation sites. Analyze habitat use for each season and sex. 6. Document reproductive parameters, movements, and survival for all radio-marked greater prairie-chickens. 7. Analyze the dispersion of female greater prairie-chickens during the breeding and nesting seasons to test hypotheses about lek evolution and territoriality. 8. Compile and analyze data, and prepare progress report. METHODS An area centered 20 km northwest of Wray, Colorado was chosen for research on greater prairie-chickens. A study area of approximately 200 km2 was monitored to determine lek density and male lek attendance. Trapping efforts were concentrated on a smaller core area of 75 km2• Birds were trapped at winter feeding sites using walk-in traps (baited with corn) and on leks using walk-in traps and cannon nets. All captured birds were banded with a numbered aluminum band and a unique combination of 3 colored plastic bands. In addition, the lengths of primary I to X, the diameter of primary IX (at the base, immediately below the barbs), the length of the pinnae, and weight were measured. Age was ascertained by examining patterns of feather wear (Ammann 1944). Bird ages were: yearlings, 5 to 17 months of age (1 Nov of 1st year to 31 Oct of 2nd year) and adults, older than 17 months of age (after 31 Oct of 2nd year). Battery- and solar-powered radio transmitters were attached to poncho-type markers (Amstrup 1980) and placed on greater prairJe-chickens in both 1986 and 1987 (Table 1). Radio weights ranged between 1.8 and 2.3% of each bird's body weight. �272 Table 1. Number of greater prairie-chickens banded and fitted with radio transmitters, and their fates, in northeastern Colorado during 1986 ad 1987. Capture data RadiosD Mortalities Fates of radio-marked birdsa Removed~ Losttl Predation Alive Cate~ory Bands Males Adults Yearlings 106 60 46 32 19 13 4 2e 2f 6 4 2 4 2 2 13 6 7 9 7 2 Females Adults Yearlings 126 62 64 81 36 4S 3 2f If 14 7 7 17 3 14 29 11 18 21 IS 6 Totals 232 113 7 20 21 42 30 aFates as of 31 Dec 1987. bBirds given radio transmitters were also banded. CAt least 14 radios were recovered after they fell off birds. dBirds potentially were lost because of several reasons including 1) long untrackable movements by radio-marked birds; 2) broken radios on the live birds; and 3) broken radios on dead birds. eTwo birds in a single trap died of heat stress. fRaptors killed S birds in traps in a 3-day period. Seasonal collection periods were defined as winter (1 Nov-14 Feb), early spring (IS Feb-3l Mar), late spring (1 Apr-IS May), early summer (16 May-30 Jun), late summer (1 Jul-IS Aug), and fall (16 Aug-3l Oct); designation of seasons was based on aspects of breeding behavior and movement (Robel et al. 1970). Radio-marked prairie-chickens were tracked using a portable receiver and a 3-element yagi antenna. Each bird was visually observed once every 21-28 days and numerous additional observations were obtained by triangulation; azimuths were obtained within 1.0 km of the target transmitters and at angles-of-incidence greater than 3So and less than l4So• Initial estimates of accuracy suggested that locations derived by triangulation had a 9S% probability of being within 200 m of the actual location. All locations were recorded using Universal Transverse Mercator cordinates (nearest 10-m interval). Home range size was estimated as the area within a 7S% probability contour generated with harmonic means for each radio-tracked bird for each season (Dixon and Chapman 1980). Habitat was examined at both observed and 'available' sites. Available sites were chosen relative to observed sites (modification of a stratified sampling method) and were randomly selected within a O.S-km circle (O.S km was representative of a typical prairie-chicken flight distance) centered over the observed site. One available site was recorded for each observed site. To eliminate problems associated with measuring habitat variables in a changing environment (e.g., snow cover, plant growth, grazing pressure), both sites were examined on the same day. Two l8-m perpendicular transects were established in the center of the site, orientation of the initial transect was randomly determined. Ten point-intercept locations, 2 m apart, were located �273 along each transect (total of 20 points). All plant species intercepted at each point were identified and recorded. A height-density-index (HOI) was recorded from a height of 1 m and at a distance of 4 m to one side of the transect for all 20 points. The HDI was recorded as the height of vegetation obstructed on a Robel Pole (to the nearest 5 cm). Heights of sand sagebrush (Artemisia filifolia), grasses, and forbs were recorded to the nearest 5 cm. A single 25-m2 circle was also centered on each site (2.82 m diameter) and all plant species within the circle were identified and recorded. Location, slope, and aspect were also recorded at each site. Bradbury's (1981) female preference hypothesis will also be tested. The female preference hypothesis predicts that most females should have home ranges that incorporate only 1 lek, and that each female should visit only the lek(s) within her home range. Two null hypotheses will be tested with X2 tests: 1) the probability of a female visiting 2 or more leks during aparticular breeding seasn is 50% (50% is a conservative interpretation of 'most'); and 2) the probability of a femal~ nesting closer to a lek that is different than the lek where she was captured is equal to 50%. RESULTS Three different trapping methods were used to capture 232 greater prairie-chickens during 1986 and 1987 (Table 1). Walk-in traps were particularly effective for capturing birds on both winter feeding areas and on leks (Table 2). Males were larger than females for all feather measurements and weights (P <0.01). In addition, adults were generally larger than yearlings for-each sex (Table 3). The results also indicated that certain measurements may be particularly effective for differentiating between adults and yearlings. Among those, the lengths of primaries I, II, and IX and the diameter of primary IX appeared to be best for discrimination. Although body weights also differed by age and sex, seasonal variations in weights were detected (Table 4). For example, females weighed more during the breeding season than in winter (~< 0.05); males did not differ. Table 2. Numbers of greater prairie-chickens captured by different techniques in 1986-87 in northeastern Colorado (including recaptures). Cannon nets at lek sites Total 61 42 19 21 14 7 141 81 60 41 25 16 101 49 52 6 2 4 148 76 72 100 162 27 289 Category Walk-in traps at winter feeding sites Males Adults Yearlings 59 25 34 Females Adults Yearlings Totals Walk-in traps at lek sites �N '-J Table 3. Measurements of greater prairie-chickens captured in northeastern Colorado in 1986 and 1987. Fema1esa Ma1esa Adults x SD 11.69 12.02 12.63 13.96 16.40 17.12 17.28 17.10 16.22 13.06 0.39 0.35 0.41 0.48 0.57 0.60 0.47 0.83 0.57 0.96 32 31 30 32 31 33 31 43 43 44 Primary IX diameter (mm) 39 3.41 0.11 Pinnae length (cm) 49 0.47 Measurement N Primary length (cm) I 54 II 54 III 54 IV 52 V 51 VI 54 VII 54 VIII 63 IX 62 X 65 7.93 +-- Yearlings x Adults SD pb N. 11.21 11.75 12.43 13.65 16.23 17.09 17.31 16.83 15.69 13.25 0.34 0.28 0.31 0.44 0.50 0.60 0.45 0.97 0.40 0.95 *** *** * ** 57 57 57 57 56 57 55 68 68 68 40 3.21 0.10 *** 26 7.72 0.53 N *** X SD 11.34 11.71 12.29 13.45 16.66 16.37 16.50 16.18 15.39 12.55 0.44 0.64 0.72 0.64 0.57 0.54 0.61 1.11 0.70 0.90 55 55 55 55 54 53 53 63 63 64 N Year1in~s x SD pb 10.85 11.32 11.96 13.05 15.32 16.18 16.45 16.19 14.97 12.52 0.31 0.31 0.38 0.39 0.49 0.46 0.41 0.63 0.53 0.58 *** *** ** *** ** *** 47 3.27- 0.11 46 3.14 0.12 49 3.78 0.50 50 3.62 0.52 *** Weight (g) 78 1030.7 59.4 57 1005.6 42.2 ** 76 901.9 59.5 69 877.7 54.6 aThe differences between measurements for males and females within each age category were all significant at p < 0.01 (t test). - bThe probability for differences in measurements (!test) between adults and yearlings within each category of sex were: * = R. < 0.05; ** = R. < 0.01; and *** = p < 0.001. * �275 Table 4. Comparison of weights (!test) for greater prairie-chickens captured during the breeding season (15 Feb-3l May) and winter (1 Nov-14 Feb). N Winter x SD N Breeding season SD x P Males Adults Yearlings 26 32 1033.7 1007.8 73.2 42.6 52 25 1029.2 1002.8 51.9 42.5 0.784 0.661 Females Adults Yearlings 26 16 879.6 845.0 56.9 47.3 50 53 913.5 887.5 58.0 53.1 0.018 0.005 Density Thirty-eight active leks were documented on the study area during both 1986 and 1987 (Table 5). Twenty-one percent (8 of 38) of the leks that were active in 1986 were not active in 1987 (8 new leks were found in 1987). The density of leks on the study area was approximately 0.19 leks/km2 (0.49 leks/miles2) in both 1986 and 1987. The mean lek attendance was 6.69 males/lek in 1986 and 6.95 males/lek in 1987. Density of displaying males was approximately 1.27 males/km2 (3.25 males/mile2) in 1986 and 1.32 males/km2 (3.38 males/mile2) in 1987. Male attendance at leks appeared to be fairly constant from early March to early June, whereas female attendance (as represented by trapping success) showed a dramatic peak during the first 3 weeks of April (Table 6). Survival Radio-marked greater prairie-chickens were monitored as long as possible past the date of capture (Table 1). Forty-two birds died; examination of kill characteristics suggested that at least 22 were taken by coyotes (Canus latrans), 12 by avian predators (at least 1 Swainson's hawk [Buteo swainsoni], 1 ferruginous hawk [Buteo rega1is], and 1 great-horned owl [Bubo virginianus], and 8 by unknown predators. Other predators were also observed at fresh kills of greater prairie-chickens, including golden eagles (Aquila chrysaetos), red-tailed hawks (Buteo jamaicensis), and a northern harrier (Circus c aneus). Birds were also killed in collisions with vehicles and power lines and or fences (1 such kill was carried to a farm house by a domestic cat). Twenty-one radio-marked birds were 'lost' because of broken radios, or because the birds moved too far from the study area to be found. If broken radios were a problem, then 'lost' birds should have been distributed equally among the age and sex-categories (Table 1). However, yearling females 'disappeared' more frequently than adults and males (X2 = 8.071; P <0.05), suggesting that they may be more likely to make long movements away-from the study area. �276 Table 5. Location of active greater prairie-chicken leks on the study area in northeastern Colorado and the median number of males attending the 1ek during the breeding season (a plus sign symbolizes an active 1ek without an accurate count of males). Universal Transverse Mercators (Zone 12) Meters North Meters East 714880 715830 716370 716610 716670 717050 717100 717150 717250 718350 718130 718690 718860 719340 719630 719920 720060 720620 720980 721900 722100 722440 722850 723020 723300 723450 724110 724270 724420 724830 724960 725280 725870 726290 726410 726520 726700 727280 727450 728280 728630 728730 730390 731000 732420 733080 4453420 4448010 4453120 4456480 4453840 4455600 4457710 4448870 4454290 4449920 4450100 4453530 4457680 4451710 4453920 4449630 4448250 4455520 4458240 4455230 4453700 4453940 4456700 4456460 4458750 4455900 4453510 4459920 4449180 4448130 4447950 4450980 4445950 4447050 4449940 4455730 4450140 4444810 4454630 4447390 4448610 4445330 4446390 4447120 4445100 4446330 TownshiE 3N 2N 3N 3N 3N 3N 3N 2N 3N 2N 2N 3N 3N 3N 3N 2N 2N 3N 3N 3N 3N 3N 3N 3N 3N 3N 3N 3N 2N 2N 2N 3N 2N 2N 2N 3N 2N 2N 3N 2N 2N 2N 2N 2N 2N 2N Legal location Section Ran~e 46W 46W 46W 46W 46W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 44w 44w 44W 44W 44W 44w 44W 44W 44W 44W 44w 25 12 25 13 24 18 7 7 19 6 6 29 8 32 28 5 8 16 9 22 27 22 15 15 2 14 26 2 2 11 12 36 13 13 1 18 6 19 19 17 8 20 16 16 22 14 Quarter NW NW NE NE SE SW SW NW SW NE NE NW SW NE SW SE NE SW NE NW NW SE NE NE SW SW NE NE SE SE SW SW SE NE SE SW NW SE SE NW NW NW S.W NE SE SW Attendance 1986 1987 + + 3 5 6 3 6 7 13 8 0 5 0 3 0 14 0 0 5 15 11 0 5 3 4 0 2 5 9 11 7 7 2 2 0 11 9 8 + 3 8 9 7 8 6 4 3 9 0 9 9 2 4 15 12 8 2 0 2 0 2 17 2 2 6 8 12 4 4 5 0 2 0 5 8 6 7 8 5 0 2 7 8 9 11 0 7 10 18 10 4 0 �277 Table 6. Trapping success rate (percent captures per trap per day) of greater prairie-chickens in northeastern Colorado. Trapping week 4-10 11-17 18-24 25-31 1- 7 8-14 15-21 22-28 Mar Mar Mar Mar Apr Apr Apr Apr Trap days Males Females Totals 62 59 167 348 386 274 223 91 3.2 1.7 3.0 0.9 5.7 7.3 4.0 4.4 0.0 0.0 1.2 2.6 8.8 13.5 9.0 1.1 3.2 1.7 4.2 3.4 14.5 20.8 13.0 5.5 Reproductive Success In 1986, 20 nests had a mean date of hatch of 10 June (som~hatch dates were predicted based on the known onset of incubation). First nests had a mean hatch date of 1 June (N = 10), while probable, or known ~enesters (based on the presence of a brood patch on a female visiting a lek or the known failure of a female's first nest), had a mean hatch date of 19 June (!= 10). In 1987, the mean date of hatch was 4 June. First nests had a mean hatch date of 4 June (N = 23) and renests had a mean hatch date of 15 June (N = 2). Six nests (4-renests and 2 first nests) successfully hatched an av;rage of 4.8 chicks (33.3% hatching success) in 1986 and 11 nests (all first nests) successfully hatched an average of 6.7 chicks (40.7% hatching success) in 1987. Movement Home range size of greater prairie-chickens was estimated by sex and age class for each season (Table 7). Yearling males tended to have larger home ranges than adult males for all seasons. Anecdotal observations of lek visitation by males indicated that most males were observed attending the same lek where they were captured. Of 5 exceptions, 4 were yearlings. One yearling male visited at least 5 different leks in 1 breeding season. When age categories were combined within each sex and the sexes were compared with t tests, males were found to have smaller home ranges than females during the late spring (P = 0.003), early summer (p = 0.006), and fall (p =0.026). Results for the other seasons were not significant (p >0.05), however, the trends were all in the same direction. Comparisons of male home range size by season showed that male home range size was relatively stable throughout the year. Conversely, females had larger (p <0.05) home ranges during the early summer and small home ranges during the-late summer and early spring. The early summer increase in female movement was particularly noticeable since females made movements up to 48 km following predation loss of their nests. Behavior also appeared to affect the size of female home ranges during late summer and fall. Females with broods tended to have larger home ranges than females without (Table 8). �278 Table 7. Home range size (area within 75% probability contours generated with harmonic means, ha) of greater prairie-chickens in northeastern Colorado during 1986 and 1987 (years combined). Category Adults Males Yearlings Totals Adults Females Yearlings Totals Totals Early spring N Median x \. SD 5 38.8 45.1 44.4 1 133.4 133.4 6 39.3 59.8 53.6 3 256.2 308.4 175.4 2 90.1 90.1 89.7 5 165.0 221.1 178.0 11 120.9 133.1 145.6 14 79.4 92.0 35.4 5 158.7 394.0 597.8 19 92.9 171.4 213.5 25 315.9 370.1 319.4 31 252.5 453.5 520.2 56 260.5 416.3 430.6 75 212.8 354.3 375.6 9 144.0 172.3 99.3 4 357.2 435.5 247.9 13 198.3 253.3 167.9 16 240.3 1142.5 1418.7 16 167.2 519.5 990.0 32 196.4 831.0 1056.8 45 197.2 664.1 774.1 7 108.1 134.3 121.1 4 195.1 179.8 89.5 11 126.9 150.8 108.3 14 137.0 180.6 147.5 15 121.4 168.6 120.9 29 126.9 174.4 132.1 40 125.9 167.9 125.1 4 225.7 189.0 96.4 4 213.2 214.7 90.7 8 225.7 201.9 87.7 7 406.8 575.3 397.0 10 272.8 291.9 227.5 17 397.0 408.6 330.0 25 289.6 432.5 290.7 9 208.2 226.4 105.6 4 260.1 242.5 126.9 13 221.1 231.4 107.3 16 244.1 448.5 538.3 7 236.4 261.5 144.8 23 239.4 391.5 459.4 36 237.9 333.7 377 .8 Late spring N Median x SD Early summer N Median ~ SD Late' summer N Median x SD Fall N Median x SD Winter N Median K SD �27~ Table 8. Home range size (area within 75% probability contours generated with harmonic means, ha) of female greater prairie-chickens with and without broods in northeastern Colorado during the brood season (late summer and fall) of 1986-87 (years combined). Category Late summer N Median x SD Fall N Median x SD With broods Without broods Totals 12 229.9 225.3 152.5 17 120.0 138.5 105.9 29 126.9 174.4 132.1 6 442.3 592.0 391.6 11 284.7 308.6 257.6 17 397.0 408.6 330.0 Habitat Habitat variables were compared between the observed locations of radio-marked greater prairie-chickens and available sites for winter (Table 9), early spring (Table 10), late spring (Table 11), early summer (Table 12), late summer (Table 13), and fall (Table 14). No differences were found for any of the seasons, except late spring. One possible explanation for the lack of habitat differences was the large amount of variability in habitat use; greater prairie-chickens were frequently feeding in fields of corn stubble and loafing and/or roosting in residual grass and sand sagebrush cover. In late spring, birds were generally observed in areas with shorter cover (grasses and forbs), sparser grass cover, and more corn and bare ground (Table 11). As well, greater prairie-chickens often fed in fields of corn stubble during late spring and males were frequently on booming grounds (characterized by short and sparse vegetation). Observed and available habitat (all seasons combined) was examined for males (Table 15) and females (Table 16). Males were observed in areas with less corn cover than expected. Females were observed in areas with shorter grasses and forbs and with denser sand sagebrush. Examination of 35 leks indicated a considerable difference between observed and available habitat (Table 17). Leks were usually on hill or ridge-crests (relatively flat on top) with sparse, short cover. Nesting habitat also appeared to be relatively distinct (Table 18). Generally, nests were in areas with thicker and taller vegetation. Loafing (and/or roosting) habitat was similar to nesting habitat in that sand sagebrush cover was thicker and taller at observed sites than it was at available sites (Table 19). In addition, forb cover was greater and species richness was higher. Feeding sites covered a broad spectrum of habitat types, and hence, few differences between available and observed sites were detected (Table 20). Most qotable was the choice of areas with short grass cover. Sites of brood locations were characterized by greater warm season grass and forb cover (Table 21). �280 Table 9. Habitat at observed and available locations of greater prairie-chickens in northeastern Colorado during winter (1 Nov-14 Feb) 1986-87 and 1987-88. P-va1uea t Fma;l:l; Observed (26) x SD Available (26) SD )C 8.15 4.23 10.08 6.93 0.017 0.233 Height (cm) Sand sagebrushb Grasses Forbs Barec 35.38 77 .69 40.77 20.96 37.39 33.05 37.94 20.40 42.12 88.46 54.23 18.46 35.13 37.52 38.72 11.02 0.758 0.531 0.920 0.003 0.507 0.277 0.211 0.586 Cover (%) Bare Sand sagebrush Grasses Cool season grasses Need1e-and-threadd Sex weeks fescuee Warm season grasses Blue gramag Sand dropseedh Prairie sandreedi Corn Forbs 54.42 6.54 38.85 4.04 4.04 0.00 35.77 6.35 5.58 7.31 11.73 5.00 29.74 8.34 26.88 7.75 7.75 0.00 25.21 14.32 8.04 13.21 15.81 9.38 59.04 3.46 35.38 6.15 5.38 0.19 30.58 4.42 6.73 4.42 5.77 4.23 29.93 4.64 28.91 13.36 13.34 0.98 26.01 12.36 8.48 10.33 13.17 7.03 0.975 0.005 0.719 0.008 0.009 __f 0.876 0.466 0.793 0.226 0.367 0.156 0.580 0.108 0.657 0.489 0.659 0.327 0.468 0.607 0.617 0.385 0.146 0.739 Species richness (N) 8.19 6.40 9.38 5.84 0.650 0.486 Slope (degrees) 2.58 2.04 3.23 5.24 0.000 0.558 Habitat variable Height-density-index (cm) arf !max was significant, a! test for unequal variances was used. bSand sagebrush = Artemisia filifolia. CHeight of bare ground includes soil mounds, man-made objects, and snow. dNeed1e-and-thread = Stipa comata. eSix weeks fescue = Vu1pia octof10ra. fAt least one of the variances was undefined; hence the variances were assumed to be different. gB1ue grama = Boute10ua gracilis. ~Sand dropseed = Sporobo1us cryptandrus. 1Prairie sandreed = Ca1amovilfa longifo1ia. �281 Table 10. Habitat at observed and available locations of greater prairie-chickens in northeastern Colorado during early spring (15 Feb-31 Mar) 1987. Observed (5) x SD Habitat variable Available (5) x SD P-va1uea Lnax t 5.38 4.59 2.04 0.56 0.001 0.180 60.00 100.00 55.00 6.00 21.79 23.45 11.73 2.24 31.00 85.00 47.00 9.00 23.29 25.50 38.01 5.48 0.901 0.875 0.043 0.111 0.077 0.361 0.673 0.290 Cover (%) Bare Sand sagebrush Grasses Cool season grasses Need1e-and-thread Six weeks fescue Warm season grasses Blue grama Sand dropseed Prairie sandreed Corn Forbs 15.00 13.00 79.00 28.00 28.00 0.00 62.00 19.00 19.00 26.00 0.00 1.00 10.00 9.08 12.94 19.24 19.24 0.00 13.51 7.42 6.52 17.10 0.00 2.24 28.00 4.00 64.00 10.00 8.00 1.00 55.00 10.00 10.00 15.00 11.00 7.00 12.04 4.18 15.97 10.00 9.08 2.24 20.00 7.91 16.96 11.18 24.60 6.71 0.728 0.162 0.694 0.233 0.175 __c 0.056 0.100 0.079 0.141 0.101 0.069 0.374 0.535 0.101 0.300 0.263 0.374 0.094 Species richness (N) 12.80 3.27 12.00 6.81 0.178 0.821 3.20 1.64 2.40 1.14 0.496 0.397 Height-density-index (cm) Height (cm) Sand sagebrush Grasses Forbs Bareb Slope (degrees) 0.466 0.904 0.091 0.431 __ c alf !max was significant, a ! test for unequal variances was used. bHeight of bare ground includes soil mounds, man-made objects, and snow. CAt least one of the variances was undefined; hence the variances were assumed to be different. �282 Table 11. Habitat at observed and available locations of greater prairie-chickens in northeastern Colorado during late spring (1 Apr-15 May) 1987. Observed (38) SD x Habitat variable Available (38) SD x P-va1uea £nax t 3.12 2.43 3.26 2.53 0.805 0.800 Height (cm) Sand sagebrush Grasses Forbs Bareb 51.05 73.03 44.34 8.82 43.00 34.46 42.08 4.10 66.71 98.16 71.05 6.45 30.43 20.01 35.42 2.58 0.039 0.001 0.299 0.006 0.071 0.000 0.004 0.004 Cover (%) Bare Sand sagebrush Grasses Cool season grasses Need1e-and-thread Six weeks fescue Warm season grasses Blue grama Sand dropseed Prairie sandreed Corn Forbs 28.95 8.42 60.92 24.08 16.18 5.13 41.58 15.13 6.58 6.32 4.08 9.21 22.37 11.03 21.21 18.56 16.08 8.26 19.11 17.38 6.89 7.68 9.85 17.18 19.34 6.05 71.05 30.79 21.71 9.47 46.58 12.37 14.34 9.74 0.13 9.08 11.28 8.63 17.71 20.62 20.58 11.50 15.77 14.92 15.99 10.65 0.81 9.36 0.000 0.140 0.278 0.526 0.139 0.048 0.248 0.358 0.000 0.050 0.000 0.000 0.022 0.301 0.027 0.140 0.196 0.063 0.217 0.459 0.008 0.113 0.019 0.967 Species richness (N) 12.89 8.07 16.18 5.84 0.054 0.045 1.95 1.66 3.00 3.08 0.003 0.069 Height-density-index Slope (degrees) (cm) alf !max was significant, a ! test for unequal variances was used. bHeight of bare ground includes soil mounds, man-made objects, and snow. �283 Table 12. Habitat at observed and available locations of greater prairie-chickens in northeastern Colorado during early summer (16 May-30 Jun) 1987. Observed (33) Habitat variable x SD Available (33) x SD P-va1uea max t 3.46 2.77 3.38 1.92 0.041 0.894 Height (cm) Sand sagebrush Grasses Forbs Bareb 67.88 99.09 66.52 6.82 33.50 27.37 29.65 2.74 61.97 97.58 78.03 6.67 37.25 38.10 44.19 3.23 0.552 0.066 0.027 0.363 0.500 0.853 0.219 0.838 Cover (%) Bare Sand sagebrush Grasses Cool season grasses Need1e-and-thread Sex weeks fescue Warm season grasses Blue grama Sand dropseed Prairie sandreed Corn Forbs 18.64 6.06 71.36 32.12 16.21 10.76 48.64 14.24 8.48 8.03 1.06 13.03 15.53 7.04 16.92 20.95 15.46 10.01 16.02 14.31 9.72 9.60 4.29 12.74 19.09 6.21 70.00 33.79 22.12 8.48 46.97 13.33 7.42 12.58 1.67 10.91 20.78 7.61 24.65 26.34 20.69 12.90 20.08 16.04 9.36 14.37 5.40 11.95 0.104 0.667 0.037 0.201 0.104 0.157 0.207 0.523 0.834 0.025 0.197 0.720 0.920 0.933 0.794 0.777 0.194 0.427 0.711 0.809 0.653 0.136 0.615 0.488 Species richness (N) 21.06 7.57 19.15 7.95 0.786 0.322 1.79 1.47 2.27 2.14 0.039 0.288 Height-density-index Slope (degrees) (cm) alf !max was significant, a t test for unequal variances was used. bHeight of bare ground includes soil mounds, man-made objects, and snow. �284 Habitat at observed and available locations of greater Table 13. prairie-chickens in northeastern Colorado during late summer (1 Jul-15 Aug) 1986-87. Observed (69) SD x Habitat variable Available (69) SD x P-va1uea t lmax 4.78 3.60 3.88 2.73 0.024 0.100 61.67 102.83 68.26 4~35 32.10 22.86 30.96 3.92 50.94 100.65 64.64 5.14 32.22 23.07 31.72 10.98 0.975 0.939 0.843 0.000 0.052 0.579 0.498 0.572 Cover (%) Bare Sand sagebrush Grasses Cool season grasses Need1e-and-thread Six weeks fescue Warm season grasses Blue grama Sand dropseed Praire sandreed Corn Forbs 14.35 10.29 73.33 30.00 22.10 8.04 52.25 12.61 10.29 13.12 1.16 13.70 8.66 10.00 15.16 17.88 16.50 9.97 15.11 10.10 10.50 10.33 3.94 11.87 17.03 8.62 72.75 32.90 24.06 7.32 48.91 16.30 9.71 11.59 0.43 10.87 11.70 10.21 17.25 18.20 17.20 8.32 16.93 15.09 10.77 10.13 1.66 10.88 0.134 0.859 0.291 0.886 0.735 0.155 0.351 0.001 0.831 0.871 0.000 0.474 0.129 0.334 0.834 0.347 0.497 0.645 0.225 0.094 0.749 0.384 0.163 0.147 Species richness (N) 20.29 5.65 18.96 5.38 0.686 0.158 2.26 2.20 2.57 2.65 0.129 0.464 Height-density-index (cm) Height (cm) Sand sagebrush Grasses Forbs Bareb Slope (degrees) alf !max was significant, a ! test for unequal variances was used. bHeight of bare ground includes soil mounds, man-made objects, and snow. �285 Table 14. Habitat at observed and available locations of greater prairie-chickens in northeastern Colorado during fall (16 Aug-31 Oct) 1986-87. Observed (51) x Habitat variable SD Available (51) x SD P-va1uea Lnax t 6.74 12.00 12.17 21.68 0.000 0.122 Height (cm) Sand sagebrush Grasses Forbs Bareb 45.88 93.53 54.80 5.98 31.32 35.86 33.36 4.24 33.14 111.18 60.69 7.35 31.80 49.93 34.35 4.40 0.915 0.021 0.837 0.802 0.044 0.043 0.382 0.112 Cover (%) Bare Sand sagebrush Grasses Cool season grasses Need1e-and-thread Six weeks fescue Warm season grasses Blue grama Sand dropseed Prairie sandreed Corn Forbs 17.16 8.43 72.25 21.86 11.96 4.71 58.92 12.25 14.02 10.59 6.67 13.14 13.39 10.22 18.01 18.97 14.77 7.17 15.92 15.31 14.70 13.33 19.38 15.30 19.90 4.71 72.25 15.69 12.75 2.65 62.55 15.39 12.45 9.12 10.98 11.08 12.02 6.59 15.98 16~-76 16.01 4.93 17.56 18.86 14.26 13.85 23.47 11.85 0.449 0.002 0.401 0.384 0.570 0.009 0.489 0.143 0.832 0.789 0.179 0.074 0.279 0.031 1.000 0.085 0.798 0.094 0.277 0.359 0.586 0.586 0.314 0.449 Species richness (N) 16.47 6.72 14.98 7.36 0.522 0.288 2.51 3.26 2.49 2.96 0.503 0.975 Height-density-index Slope, degrees (cm) arf !max was significant, a t test for unequal variances was used. bHeight of bare ground includes soil mounds, man-made objects, and snow. �286 Table 15. Habitat at observed and available locations for male greater prairie-chickens in northeastern Colorado during 1986-87. Observed (92) x Habitat variable SD Available (92) x SD P-valuea .F-max t 5.82 9.68 8.40 16.61 0.000 0.199 Height (cm) Sand sagebrush Grasses Forbs Bareb 50.71 92.12 53.70 7.77 35.70 36.95 38.18 7.12 53.21 102.66 60.16 8.53 35.82 42.53 38.88 7.43 0.974 0.182 0.862 0.687 0.636 0.074 0.257 0.479 Cover (%) Bare Sand sagebrush Grasses Cool season grasses Needle-and-thread Sex weeks fescue Warm season grasses Blue grama Sand dropseed Prairie sandreed Corn Forbs 24.08 7.50 67.55 23.37 15.98 5.05 50.98 15.27 8.75 10.11 3.91 8.53 20.86 8.60 20.96 18.78 15.54 7.90 17.78 14.94 11.06 11.24 10.94 10.81 25.65 6.09 66.36 23.04 18.10 4.46 49.67 13.53 8.48 10.38 5.92 8.97 22.63 8.15 23.17 21.90 18.94 9.12 20.83 15.54 9.80 12.00 16.98 11.30 0.438 0.610 0.340 0.145 0.060 0.171 0.132 0.709 0.250 0.533 0.000 0.669 0.624 0.254 0.714 0.914 0.408 0.635 0.648 0.440 0.860 0.874 0.034 0.790 Species richness (N) 15.18 7.72 14.33 7.31 0.610 0.440 1.86 2.01 2.41 2.39 0.102 0.090 Height-density-index Slope (degrees) (cm) alf !max was significant, a ! test for unequal variances was used. bHeight of bare ground includes soil mounds, man-made objects, and snow. �287 Table 16. Habitat at observed and available locations for female greater prairie-chickens in northeastern Colorado during 1986-87. Observed (130) SD x Habitat variable P-va1uea Kma~ t 4.70 2.93 4.80 4.83 0.000 0.837 Height (cm) Sand sagebrush Grasses Forbs Bareb 56.38 91.96 59.85 7.88 35.86 28.15 33.09 10.49 47.23 98.81 68.77 7.19 33.81 28.64 34.17 9.38 0.505 0.846 0.716 0.206 0.035 0.053 0.033 0.575 Cover (%) Bare Sand sagebrush Grasses Cool season grasses Need1e-and-thread Six weeks fescue Warm season grasses Blue grama Sand dropseed Prairie sand reed Corn Forbs 21.96 9.27 66.19 25.04 15.85 6.77 48.81 10.73 10.69 10.31 4.27 13.42 21.11 10.38 22.25 20.19 16.59 9.44 19.81 13.02 11.06 11.84 13.12 15.28 22.08 6.31 68.08 26.50 18.31 6.77 49.12 13.38 11.85 9.88 2.38 10.31 19.40 8.43 22.89 21.-20 18.48 9.13 20.60 16.43 14.03 12.06 10.02 10.28 0.321 0.019 0.748 0.579 0.221 0.702 0.660 0.009 0.007 0.833 0.002 0.000 0.964 0.012 0.501 0.570 0.260 1.000 0.902 0.150 0.462 0.776 0.194 0.055 Species richness (N) 17.73 7.87 17.73 6.64 0.054 1.000 2.53 2.45 2.82 3.52 0.000 0.438 Height-density-index .Slope (degrees) (cm) Available (130) SD x alf !max was significant, a ! test for unequal variances was used. bHeight of bare ground includes soil mounds, man-made objects, and snow. �288 Table 17. Habitat at observed and available 1ek locations of greater prairie-chickens in northeastern Colorado during 1986-87. Observed (35) Habitat variable Height-density-index Y x SD l:-va1uea ¥max t 1.12 0.76 3.63 2.57 0.000 0.000 Height (cm) Sand sagebrush Grasses Forbs Bareb 32.29 60.00 39.43 6.86 16.99 28.18 38.40 2.99 52.71 95.00 50.57 7.29 32.21 31.67 35.70 2.80 0.000 0.500 0.673 0.706 0.002 0.000 0.213 0.538 Cover (%) Bare Sand sagebrush Grasses Cool season grasses Need1e-and-thread Six weeks fescue Warm season grasses Blue grama Sand dropseed Prairie sandreed Corn Forbs 28.00 3.57 68.86 26.57 17.00 8.29 47.43 25.43 5.71 8.43 0.00 2.43 9.64 4.13 10.51 13.33 12.44 11.56 15.16 18.29 7.49 7.93 0.00 6.23 19.14 4.86 75.29 32.00 25.14 8.71 51.00 14.14 17.57 11.14 0.57 6.43 14.53 7.12 14.09 21.67 19.83 13.47 16.66 14.01 15.55 12.31 3.38 7.33 0.019 0.002 0.092 0.006 0.008 0.379 0.586 0.125 0.000 0.012 0.345 0.004 0.359 0.034 0.212 0.044 0.887 0.352 0.005 0.000 0.277 0.324 0.017 Species richness (N) 11.69 5.95 13.97 4.99 0.308 0.086 0.54 0.56 2.40 2.34 0.000 0.000 Slope (degrees) (cm) SD Available (35) __c alf !max was significant, a ! test for unequal variances was used. bHeight of bare ground includes soil mounds, man-made objects, and snow. CAt least one of the variances was undefined; hence the variances were assumed to be different. �289 Table 18. Habitat at observed and available nest site locations for greater prairie-chickens in northeastern Colorado during 1986-87. Observed (53) x SD Habitat variable Available (53) x SD P-va1uea 1max .t. 5.16 2.12 2.79 2.00 0.689 0.000 74.34 108.77 67.08 3.49 30.60 19.34 34.38 3.19 59.91 98.11 61.60 5.47 32.59 26.77 34.13 15.07 0.652 0.021 0.959 0.000 0.021 0.021 0.413 0.353 Cover (%) Bare Sand sagebrush Grasses Cool season grasses Need1e-and-thread Six weeks fescue Warm season grasses Blue grama Sand dropseed Prairie sandreed Corn Forbs 11.79 11.98 74.72 38.02 28.21 10.75 43.77 10.85 11.79 11.51 0.28 13.96 7.08 8.28 15.20 21.54 19.59 12.95 17.97 11.21 11.14 9.18 1.52 11.28 21.32 6.89 67.92 31.23 21.32 10.85 43.30 10.94 8.02 10.00 0.28 11.13 18.22 7.29 20.20 19.71 18.99 12.08 18.00 11.69 10.89 11.05 1.52 10.27 0.000 0.359 0.043 0.525 0.824 0.618 0.991 0.766 0.870 0.184 1.000 0.500 0.001 0.001 0.053 0.093 0.069 0.969 0.893 0.966 0.081 0.446 1.000 0.180 Species richness (N) 21.13 5.86 19.98 6.06 0.811 0.323 1.85 1.73 2.94 3.40 0.000 0.040 Height-density-index (cm) Height (cm) Sand sagebrush Grasses Forbs Bareb Slope (degrees) alf !max was significant, a t test for unequal variances was used. bHeight of bare ground includes soil mounds, man-made objects, and snow. �290 Table 19. Habitat at observed and available loafing (and/or roosting) sites for greater prairie-chickens in northeastern Colorado during 1986-87. Observed (75) Habitat variable Height-density-index x (cm) SD Available (75) x SD P-va1uea Lnax t 5.94 7.53 5.93 11.14 0.001 0.994 64.60 103.80 65.13 6.53 33.35 28.19 33.35 5.00 47.20 99.67 68.40 7.00 34.78 36.72 37.75 5.58 0.718 0.024 0.288 0.350 0.002 0.441 0.575 0.590 Cover (%) Bare Sand sagebrush Grasses Cool season grasses Need1e-and-thread Six weeks fescue Warm season grasses Blue grama Sand dropseed Prairie sandreed Corn Forbs 19.67 10.80 67.53 25.73 15.60 6.20 49.73 11.80 11.13 10.47 2.27 13.00 18.42 10.37 20.49 18.32 15.77 8.09 19.10 12.72 10.70 11.28 9.60 13.00 22.47 5.40 68.00 25.60 19.80 4.93 49.13 10.73 9.87 10.60 3.73 9.07 19.55 7.06 22.63 22.60 19.84 7.60 20.11 14.13 10.23 11.91 12.97 10.80 0.612 0.001 0.395 0.073 0.050 0.593 0.659 0.368 0.700 0.639 0.010 0.114 0.368 0.000 0.895 0.968 0.153 0.325 0.852 0.628 0.460 0.944 0.433 0.046 Species richness (~) 18.81 6.86 15.63 7.26 0.630 0.006 2.83 2.91 2.88 3.76 0.028 0.923 Height (cm) Sand sagebrush Grasses Forbs Bareb Slope (degrees) alf !max was significant, a ! test for unequal variances was used. bHeight of bare ground includes soil mounds, man-made objects, and snow. �291 Table 20. Habitat at observed and available feeding sites for greater prairie-chickens in northeastern Colorado during 1986-87. Observed (112) Habitat variable Height-density-index x (cm) SD Available (112) X SD Lnax t 5.49 6.71 7.36 13.10 0.000 0.181 Height (cm) Sand sagebrush Grasses Forbs Bareb 49.64 87.77 56.25 9.11 38.01 33.02 36.14 12.08 47.59 100.71 64.87 8.57 35.07 36.77 36.03 11.08 0.397 0.259 0.974 0.361 0.675 0.006 0.075 0.730 Cover (%) Bare Sand sagebrush Grasses Cool season grasses Need1e-and-thread Six weeks fescue Warm season grasses Blue grama Sand dropseed Prairie sand reed Corn Forbs 25.49 7.90 64.11 22.72 14.87 5.49 48.17 8.97 8.97 9.73 6.34 12.10 23.91 9.53 23.77 21.50 16.61 8.85 20.19 11.55 11.45 12.34 14.78 15.06 25.67 6.29 65.36 22.46 15.22 5.22 40.24 13.17 11.43 9.20 4.11 10.76 23.33 8.10 24.92 19;85 17.01 8.42 21.77 15.51 14.66 11.52 14.37 10.83 0.798 0.089 0.619 0.403 0.802 0.599 0.429 0.002 0.010 0.471 0.765 0.001 0.955 0.175 0.701 0.923 0.874 0.817 0.703 0.023 0.164 0.737 0.253 0.446 Species richness (N) 16.13 8.71 16.79 7.16 0.040 0.536 2.29 1.91 2.54 2.79 0.000 0.451 Slope (degrees) alf !max was significant, a t test for unequal variances was used. bHeight of bare ground includes soil mounds, man-made objects, and snow. �292 Table 21. Habitat at observed and available brood locations for greater prairie-chickens in northeastern Colorado during 1986-87. Observed (37) SD x Habitat variable Height-density-index (cm) Available (37) SD x P-va1uea E.roa:Q; t 4.82 2.84 4.55 3.03 0.699 0.703 67.16 104.19 74.32 5.41 27.25 23.02 25.09 3.98 57.03 110.68 73.92 4.46 31.15 18.42 35.96 3.49 0.426 0.185 0.048 0.441 0.141 0.185 0.955 0.281 Cover (%) Bare Sand sagebrush Grasses Cool season grasses Need1e-and-thread Six weeks fescue Warm season grasses Blue grama Sand dropseed Prairie sandreed Corn Forbs 13.78 9.46 74.86 29.59 19.19 7.43 55.41 11.89 13.92 11.08 1.08 17.03 7.76 9.26 13.56 19.66 16.39 9.25 15.29 12.93 12.26 9.36 4.43 12.61 18.65 10.81 68.65 31.49 22.43 6.76 45.14 12.30 12.84 7.70 0.27 11.49 10.71 11. 70 16.31 18.33 15.62 8.84 17.26 16.36 13.31 8.13 1.15 9.12 0.057 0.166 0.273 0.675 0.733 0.785 0.471 0.163 0.623 0.401 0.000 0.056 0.028 0.583 0.079 0.670 0.387 0.749 0.008 0.906 0.717 0.102 0.288 0.034 Species richness (N) 22.54 5.45 21.38 5.40 0.950 0.360 2.59 2.02 3.19 3.65 0.001 0.389 Height (cm) Sand sagebrush Grasses Forbs Bareb Slope (degrees) alf !max was significant, a! test for unequal variances was used. bHeight of bare ground includes soil mounds, man-made objects, and snow. �293 Female Preference Hypothesis Overall, females moved a mean distance of 2.86 km (1.78 miles) between leks where they were captured and their nests (Table 22). Forty-one of 52 (78.8%) females nested closer to a different lek than the one at which they were captured (Fig. 1). When compared with the null hypothesis value of 50% (as predicted by Bradbury 1981), the actual result was higher (X2 = 9.439; P 0.003). Table 22. Distances (km) between nests and leks where females were captured and the lek nearest to their nest in 1986 (N = 21) and 1987 (N = 31) in northeastern Colorado. Category Capture lek Median x- SD Nearest lek Median X SD 1986 1987 Combined 2.09 2.65 2.11 1.77 3.01 4.33 1.91 2.86 3.43 0.83 0.91 0.55 0.96 1.07 0.72 0.92 1.01 0.65 Lek visitation by females was greater than predicted by Bradbury's (1981) female preference hypothesis (Table 23). Thirty-two of 38 (84.2%) females that visited at least 1 lek after being captured, visited more than 1 lek. When compared with the null hypothesis value of 50%, the actual result was higher (X2 = 10.074; P = 0.001). Table 23. Minimum number of leks visited during a breeding season by radio-marked female greater prairie-chickens in northeastern Colorado in 1986-87. N leks visited N % 1 2 3 4 26 18 11 3 44.8 31.0 19.0 5.1 All females Females observed on at least 1 lek after being captured % N 6 18 11 3 15.8 47.4 29.0 7.9 �294 1986 o o o o N o o Lek * o o o Nest o 0 o o 1987 0 0 0 0 0 0 0 00 0 0 0°1** 0 0 0 0 0 0 0 0 0 5km Fig. 1. Greater prairie-chicken nests in relation to respective leks of capture in northeastern Colorado in 1986 (~= 21) and 1987 (~= 31). �295 DISCUSSION Few data have been gathered on mortality, reproduction, lek attendance, movement, and habitat use by greater prairie-chickens in Colorado. Some sample sizes in this study are still too small to infer clear conclusions, however certain trends are apparent. Males apparently have site fidelity to a particular lek and can be found on the same lek every day. However, little is known about the proportion of males remaining faithful to a particular lek and those that move between leks. Reproductive success improved from 1986 to 1987. However, certain difficulties exist with interpretation of these data as the biases associated with trapping are not clearly understood. Trapping intensity was greater during the latter half of spring 1986, and consequently numerous females were caught that had already failed with their first nesting attempts. The bias toward late trapping success might partially explain why the estimated hatching success rate was only 30% (previous research suggests that 2nd nests are less successful than first nests, Robel and Ballard 1974). Likewise, late trapping success in 1986 may also explain the relatively large number of renests. Although numerous hypotheses have been proposed to explain the evolution of lek behavior from a dispersed mating system, most of these hypotheses have been rejected (Davies 1978, Wittenberger 1978, Bradbury 1981, Bradbury and Gibson 1984, Payne 1984). Two hypotheses are still debated: 1) female preference for clustered males (Bradbury 1981); and settlement of males on 'hotspots' of female traffic (Bradbury et al. 1986). Both predict a positive correlation between female home range size and spacing of male clusters (leks). The first hypothesis ('female preference' hypothesis), which suggests that each lek should have its own population of females, is not supported by the preliminary findings of this study which suggests that most· females visit more than 1 lek. Likewise, long female movements to nest sites indicate that most females are not restricted to the area around a single lek. The 2nd hypothesis ('hotspot' hypothesis) will be tested later in this study. Movement of females in relation to leks is also a significant aspect of greater prairie-chicken management. The fact that females nested an average of 2.86 km from the lek at which they were captured, suggests that nest locations may be more important than leks as indications of local habitat quality. Examination of habitat has been limited to a stratified sampling method that limits examination ·of available habitat to areas relatively close to the 'observed' habitat. Several differences were detected between observed and available habitat, especially for nesting, lekking, feeding, loafing, and brooding sites. Behavior appeared to be more important than sex and season for explaining differences in habitat use. In general, the habitat differences associated with sex and season were trivial. One possible reason for the lack of significant differences may be that greater prairie-chickens use a wide variety of habitats that are dependent on their behavior. �296 LITERATURE CITED Ammann, G. A. 1944. Determining the age of pinnated and sharp-tailed grouses. J. Wildl. Manage. 8:170-171. Amstrup, S. C. 214-217. 1980. A radio-collar for game birds. J. Wildl. Manage. 44: Bradbury, J. W. 1981. The evolution of leks. Pp. 138-169 in R. D. Alexander and D. W. Tinkle, ed., Natural selection and social behavior: recent research and new theory. Chiron Press, New York, N.Y. , and R. M. Gibson. 1984. --- Bateson, ed., Mate choice. Leks and mate choice. , and I. M. Tsai. 1986. ---Behav. Anim. 34:1694-1709. Pp. 109-138 in P. Hotspots and the disperson of leks. Davies, N. B. 1978. Ecological questions about territorial behavior. 317-350 in J. R. Krebs and N. B. Davies, ed., Behavioral ecology: evolutionary approach. Sinauer Associates, Sunderland, Mass. Pp. an Dixon, K. R., and J. A. Chapman. 1980. Harmonic mean measure of animal activity areas. Ecology 61:1040-1044. Payne, R. B. 1984. Sexual selection, lek and arena behavior, and sexual size dimorphism in birds. Ornith. Monogr. 33. 52pp. Robel, R. J., and W. B. Ballard, Jr. 1974. Lek social organization and reproductive success in the greater prairie chicken. Am. 2001. 14:121-128. ____ , J. N. Briggs, J. J. Cebula, N. J. Si1vy, C. E. Viers, and P. G. Watt. 1970. Greater prairie chicken ranges, movements, and habitat usage in Kansas. J. Wi1d1. Manage. 34:286-306. Wittenberger, J. F. 80:126-137. 1978. The evolution of mating systems in grouse. Prepared by .,.....,..,../.t...:,-:.7ldJ~..:......:..;...--lo~'---'.:...._:Jh~LI.Oc.::.~.!::..::>J2"-.c _ Michael A. Schroeder Graduate Research Assistant Approved by -=-,a~~_~-:, =-·--::-"-?_'---l..8..<..;7."",,~~ Clait E. Braun Wildlife Research Leader _ Condor �297 JOB PROGRESS REPORT State of: Project: Colorado W-152-R Avian Research Work Plan: 17 Job Title: Population Period Covered: Authors: Personnel: Job 7 --- Dynamics of White-tailed 01 January through 31 December Ptarmigan 1987 Clait E. Braun and Kenneth M. Giesen Shannon Lord and Kathy Martin, University of Alberta; Clait E. Braun and Kenneth M. Giesen, Colorado Division of \vildlife ABSTRACT Long-term studies of populations of white-tailed ptarmigan (Lagopus leucurus) were continued at hunted (Mt. Evans) and unhunted (Rocky Mountain Na~ional Park) areas in Colorado through 1987. Densities of b reed Lng ptarmigan decreased slightly at Mt. Evans but increased at Rocky Mountain National Park. Nesting success at both sites was good to excellent but brood size at Mt. Evans was poor (2.0 chicks/hen). There was no known harvest at Mt. Evans Ln 1987 because the highway was closed due to road construction. Apparently, no hunters walked the 3+ km into areas where ptarmigan were known to occur. ��299 POPULATION DYNAMICS OF WHITE-TAILED Clait E. Braun and Kenneth PTARMIGAN M. Giesen Long-term studies of trends in population size and investigation of reasons for fluctuations in size of tetraonid populations are lacking. Studies on the population dynamics of unhunted and hunted populations of white-tailed ptarmigan were init.iat.ed in Colorado in 1966 and have continued essentially unint.errupt.ed at. 2 sit.es. St.udies of t.he unhunted population (Rocky Mountain National Park) identified possible short-term cycles of 7-8 years with an amplit.ude of 25-30% bet.ween high and low breeding densities. Conversely, studies of t.he manipulat.ed populat.ion (hunt.ed) at Ht. Evans have no t indicated any cyclic pattern and it. would appear t.hat.controlled hunt.ing may mask any long-t.erm trend t.hat.may occur. ·This study is designed to examine the quest.ion whet.her whit.e-t.ailed ptarmigan are t.ruly cyclic and whether hunting affects the apparent oscillations. P. N. OBJECTIVES The goals of this investigation are t.o be able to predict the length and amplitude of cycles in whit.e-tailed ptarmigan in Colorado, to examine the impact. of hunting on cycles, and to clarify underlying causes of the apparent cycles. SEGMENT OBJECTIVES 1. Conduct breeding (May-Jun) and brood (Aug-Sep) censuses ptarmigan using tape-recorded calls of males (breeding) (broods). 2. Censuses will be conducted on previously established, defined study areas at Mt. Evans (hunted) and at Rocky Mountain National Park (unhunted). 3. Capture (noose poles) and band (aluminum and plastic color-coded bands) all umarked white-tailed ptarmigan encount.ered on study areas at Mt. Evans and at Rocky Mountain National Park. 4. Individually identify all ptarmigan observed on study areas at Mt. Evans and Rocky t·lountainNational Park through use of binoculars. 5. Make hunting season and bag limit recommendations for Mt. Evans and collect hunting data through use of volunteer wing barrels and hunter field checks. 6. Compile data, analyze results, and prepare progress of white-tailed and chicks reports. STUDY AREA AND METHODS Areas investigated were Mt. Goliath-Mt. Evans in Clear Creek County and at Tombstone Ridge-Sundance Mountain to Fall River Pass in Rocky Nountain National Park in Larimer County. The physiography, geology, location, and �300 vegetation of these study areas have been previously 1971; Braun and Rogers 1971; Giesen 1977). described (Braun 1969, Ptarmigan were located through use of tape-recorded calls (Braun et ale 1973), captured through use of telescoping noose poles (Zwickel and Bendell 1967) as described by Braun and Rogers (1971), and classified to age and sex and banded following Braun and Rogers (1971). Age of chicks was estimated following Giesen and Braun (1979). Numbered plastic bandettes were not used as in earlier years (Braun and Rogers 1971) as a color-code system using up to 4 different colored plastic bandettes was instituted in 1977-78. A check station was scheduled to be operated on the Mt. Evans highway during the opening weekend of the ptarmigan season in that area. A volunteer wing collection station was available to hunters in the area when the check station was not in operation until the season closed. A sample of hens was radio marked at Mt. Evans as part of another study (K. Martin, pers. commun.). RESULTS AND DISCUSSION Breeding Densities Mt. Evans.--Timing of breeding events in the Mt. Evans area was about 1 week later in 1987 than in 1986, probably because of a major storm on 3-5 May. During the May-early June interval, 9 pairs and 2 single males were identified. Thus, breeding densities decreased from levels documented in 1985786 (Table 1). This decrease was primarily the result of territories on lower Mt. Goliath and west Mt. Goliath being unoccupied. During the breeding season, 5 of 11 males identified were yearlings while 6 of 9 hens were yearlings. While recruitment of yearlings was good in 1987, overwinter survival of yearlings and adults identified in 1986 was poor. Kocky Mountain National Park.--Surveys of ptarmigan present on breeding territories along Trail Ridge Road in R~mP in May and June indicated the minimum breeding population was 33 birds, which was comprised of 13 pairs and 7 single males. This represents a 16 percent increase over the 28 birds (12 pairs and 4 single males) identified in 1986 (Table 1). The increased breeding densities reflect a return to average survival of adults and recruitment of yearlings. Survival of banded adults from 1986 was 63.6% (38 of 52 males, 11 of 25 females). Recruitment of chicks banded in 1986 was only 13.8% (4 of 29) although yearlings comprised 16.5% of all adult ptarmigan identified in 1987. Nesting Success and Brood Size Mt. Evans.--Eight hens were located during mid July-early September 1987 on or immediately adjacent to the study area. Five hens (62.5%) were with broods while 3 were apparently unsuccessful nesters (without chicks). Of 11 known first nests in the Mt. Evans area, 6 were successful (K. Martin, pers. commun.). The 1 known renest was also successful, thus 7 of 11 (63.6%) hens whose nests were found were successful. Average brood size to 1 September was poor (2.0 chicks/hen). Data from 10 chicks that were banded indicated hatch dates from 30 June to 23 July with most (60.0%) hatching from 8 to 19 July. Data from 7 successful known nests indicated hatching dates from 24 June to 18 July (renest) with 4 of 7 (57.1%) hatching on 5-7 july. �3Jl Table 1. 1966-87. White-tailed ptarmigan breeding densities (birds/km2), Colorado Study area Year 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1971) 1979 191)0 1981 191)2 1983 1984 1985 1986 1987 Rocky Mountain National Park (5.5 km2) 11.3 9.8 U.S 12.0 9.6 9.1 8.7 7.8 8.0 11.1 13.5 12.9 10.7 8.7 8.4 8.2 7.8 6.7 5.8 6.0 4.5 6.0 Mt Evans (4.0 km2) 3.0 2.7 2.7 2.2 2.0 4.2 7.5 6.2 6.2 6.2 6.7 >6.0 7.5 10.3 9.5 9.0 6.5 6.5 8.0 8.0 6.5 5.0 Rocky Mountain National Park.--Nest success was estimated at >90% (11 of 12 hens observed in Ju1-Aug were with broods) which is the highest since the study was initiated in 1966. Hatch dates were calculated from primary molt and growth for 44 chicks captured for banding. Hatch dates ranged from 16 June to 21 July (Median = 2 Ju1) and were among the earliest recorded. Survival of chicks to 1 September was higher than average with an average August brood size of 4.4 chicks. Harvest Mt. Evans.--The hunting season at Mt. Evans in 1987 opened on 19 September and closed on 4 October (16 days) with a bag and possession limit of 3 and 6. Thus, the season was delayed 1 week from the statewide opening as it was in 1981 and 1986. The season opening was delayed 2 weeks from 1978 to 1980 and 1982 to 1985. Prior to 1978, experimental seasons were in effect (1970-1976) or the season opened with the statewide grouse seasons (dates from 17 Aug to 14 Sep). While the season was open in 1987, the Ht. Evans road was closed (gate) to all vehicular traffic because of road rebuilding in the Lincoln Lake area. Thus, no check station was operated on opening weekend but a volunteer wing collection station was in place on the highway throughout the season. No �302 wings were received from ptarmigan, no birds were known to have been harvested, and no bands were reported. LITERATURE CITED Braun, C. E. 1969. Population dynamics, habitat, and movements of whitetailed ptarmigan in Colorado. Ph.D. Thesis, Colorado State Univ., Fort Collins. l89pp. _____ 1971. Habitat requirements of Colorado white-tailed ptarmigan. West. Assoc. State Game and Fish Comm. 51:284-292. , and G. E. Rogers. 1971. ----Colorado Div. Game, Fish and Proc. The white-tailed ptarmigan in Colorado. Parks Tech. Publ. 27. 80pp. _____ , R. K. Schmidt., Jr., and G. E. Roger~. 1973. Census of Colorado whitetailed ptarmigan with tape recorded calls. J. Wildl. Manage. 37:90-93. Giesen, K. M. 1977. Mortality and dispersal of juvenile white-tailed ptarmigan. M.S. Thesis, Colorado State Univ., Fort Collins. 55pp. , and C. E. ----white-tailed Braun. 1979. A technique for age determination of juvenile ptarmigan. J. Wildl. Manage. 43:508-511. Zwickel, F. C., and J. F. Bendell. J. Wildl. Manage. 31:202-204. Prepared by -=-=--,:&::;_",W:::--'~z_. --'~~ 1967. Clait·E. Braun Wildlife Research Leader Kenneth M. Giesen Wildlife Researcher B A snare for capturing blue grouse. _ � https://cpw.cvlcollections.org/files/original/ef585dbb03f427ad1f28eee4f55a5fa8.pdf dd74b22c36a0f839aff20687271a6f02 PDF Text Text JUJ JOB FINAL REPORT Colorado State of: Project: W-152-R (W-37-R) 23 Work Plan: 1 Job Title: Evaluation of No-till Wheat Farming Period Covered: Author: : Job Avian Research 01 January through 31 December 1987 Warren D. Snyder Personnel: W. Snyder, Colorado Division of Wildlife ABSTRACT The quantity, quality, and security of wheat stubble as nesting cover for ring-necked pheasants (Phasianus colchicus), mourning doves (Zenaida macroura), and other ground-nesting wildlife were documented under different cropping systems on a Colorado Division of Wildlife Property (1984-85) and private lands (1986-87) in eastern Colorado. Biennial wheat-fallow cropping rotations using conventional tillage methods for summer fallow continued to dominate the agricultural landscape in eastern Colorado but provided low security for nesting wildlife due to the timing of initial summer fallow tillage. A 3-year cropping rotation (wheat-row crop-fallow), termed ecofallow, is gaining rapid acceptance but comprises <5% of the cropland in most eastern Colorado localities. Its security for nesting wildlife is considered slightly better than that of conventional wheat-fallow rotations. A biennial wheat-fallow rotation using no-till fallowing has not yet gained significant acceptance among eastern Colorado farmers but has the potential of dramatically increasing both the quantity and security of nesting cover. However, recent trends toward increased use of semi-dwarf wheat varieties (2%"':19ia- to almost 60%;_1987) have progressively reduced the height-density index (HDI) of wheat stubble for nesting wildlife. Impacts have primarily affected fall to spring survival of pheasants and the nesting quality of wheat stubble under biennial no-till wheat-fallow cropping. Comparisons of wheat stubble quality with that of green wheat, native unmanaged and unpastured grass, unharvested alfalfa, cool-season tame grasses, and switchgrass (Panicum virgatum) revealed that the latter retained the highest HDI in early spring prior to vegetation growth. Green wheat and alfalfa possessed similar growth patterns. Native grass usually had a lower HPI than wheat stubble through early spring. Recommendations concerning use and management of winter wheat on Colorado Division of Wildlife properties are presented. �304 RECOMMENDATIONS 1. Biennial no-till cropping of winter wheat is recommended because it retains 100% of the wheatland in secure nesting cover for ground nesting wildlife and retains standing stubble for wildlife use from fall to spring. 2. The most practical and economical farming approaches available will be used on private lands and their impacts on wildlife usually are a minor consideration. However, farmers should be informed as to the impacts or benefits of different wheat farming approaches on wildlife including the potential values of biennial no-till cropping of winter wheat. 3. Fields of biennially-cropped winter wheat are recommended for use on Colorado Division of Wildlife (CDOW) properties in eastern Colorado when managing for pheasants and mourning doves because wheat fields provide combinations of covers for nesting, brood rearing, night-roosting, feeding, and escape. 4. Tall wheat varieties and a minimum stubble height (12 in. or 3 dm) should be required and included in CDaW sharecropping contracts. 5. Since minimal manpower is needed for no-till fallowing, the CDaw should consider eliminating sharecropping when possible and using proper equipment and property technicians to apply herbicides. Planting, fertilizing, and harvesting can be custom contracted allowing the CDaW greater control over wheat stubble quality. 6. Ecofallow and annual cropping of small grains should not be permitted on CDaW properties. �305 EVALUATION OF NO-TILL WHEAT FARMING Warren D. Snyder Wheat stubble and green wheat comprise the vast majority of cover available to ground nesting wildlife in eastern Colorado. However, the insecurity of these covers, especially wheat stubble, under conventional summer fallow has previously been documented (Snyder 1984). New reduced-till or no-till farming methods (Table 1) have been receiving increased use in eastern Colorado in efforts to increase crop production and to conserve soil, soil moisture, reduce tillage operations, and reduce labor and fuel costs. The approach that appeared to be of greatest potential benefit for wildlife was a biennial no-till winter wheat-fallow crop system where herbicides completely replace tillage in weed control management. Based on interest expressed by Division management biologists, a study to evaluate this approach on a Division of Wildlife property was implemented. However, several problems were encountered in trying to conduct this evaluation. Lack of essential equipment was a major factor. Therefore, the study and its primary objective were modified slightly and transferred to private farmland scattered over eastern (primarily northeastern) Colorado. This report presents the findings from both the 1st (1984-85) and 2nd (1986-87) phases of this study. Table 1. The amount of small grains, corn, and grain sorghum planted under no-till cropping systems in 1983 and 1986 in relation to the total amount planted in Colorado in 1986. Crop Small grains - Fall Spring Total Corn Grain Sorghum Ha planted under no-till 1983 1986 6,742 1,9l2a 1,264a 25,934 7,368 33,302 9,570a 7,056a Total ha 1986 1,434,506 329,406 1,763,914 404,836 193,126 % of Total 1.81 2.24 1.89 2.36 3.65 aThe majority of no-till corn and grain sorghum was assumed to be in wheat stubble under the ecofallow or wheat-row crop-fallow rotation. (Data extracted from Conservation Tillage Information Center 1983 and 1986 Colorado County Summaries, James E. Lake, Person. Commun.). P. N. OBJECTIVE Test biennial, annual, and ecofallow wheat and wheat-row crop no-till, and reduced tillage crop systems for increasing the quality, quantity, and security of nesting cover for ground nesting birds in eastern Colorado. The initial objective was to test a no-till wheat fallow biennial-cropping system on Colorado Division of Wildlife (CDOW) properties within eastern Colorado. A 2nd objective was to compare the quality of wheat stubble with other available or established covers for ground-nesting wildlife. �306 METHODS AND MATERIALS Background information concerning new farming methods, equipment, herbicides, wheat varieties, and soil moisture measurement techniques were obtained from the literature, personal contacts, and field demonstrations. Dr. D. Smika, Agronomist, U.S. Department of Agriculture, Agriculture Research Service (Akron, Colo.) who had worked extensively in developing no-till wheat farming systems, was a primary contact. Selection of study sites and fields during the initial phases was coordinated with CDOW management biologists. Precipitation data were obtained from U.S. Department of Commerce, National Climatic Data Center, Climatological Data Summaries for stations in eastern Colorado. These data were averaged to obtain mean monthly and mean annual totals. Precipitation accumulated over 16 months (Jan-Dec, Jan-Apr) combined with the departure of the mean April temperature from the long-term mean provided a precipitation - temperature index that was correlated with wheat growth and stubble height (Snyder 1984). Usually, all biennial no-till, annual no-till, and switchgrass fields that could be located were sampled. Other covers were randomly sampled after making an initial effort to stratify sampling among several locations and farmers within several northeastern Colorado counties. Sampling was extended into southeastern Colorado in 1986 to obtain an adequate sample of no-till treated fields (Fig. 1). §ampling was restricted to northeastern Colorado in 1987. Height-density indices (HDI) of residual and green vegetation were obtained following Robel et ale (1970) as modified by L. M. Kirsch (Unpubl. Rep., U.S. Fish and Wildl. Serv., Jamestown, N.D., 1977). Wheat stubble was sampled in early spring prior to major growth of volunteer wheat and forbs. Other covers were sampled at progressive intervals through spring to establish the pattern of growth. The starting point and direction of sampling were randomized along an accessible side of tracts or fields. A 2nd HDI was obtained within ecofallow fields within 2 weeks after they had been planted to a row crop. Progression of spring tillage of wheat stubble fields under conventional summer fallow was monitored along a route from Holyoke to near Fleming in 1986 and 1987 (Fig. 2). Monitoring was begun 1 April and continued at 2-week intervals until >95% of all fields had been cultivated. Progression of slot-planting of row crops or drilling of millet within ecofallow stubble fields was monitored at 7-10 day intervals along a route in northwestern Phillips County during 1986-87 (Fig. 2). Monitoring began in late April and continued into June. Definitions Annual Winter Wheat Cropping System.--The system by which winter wheat is harvested in mid-summer and planted in the subsequent early fallon an annual basis. Conventional tillage is used to reduce the residual stubble prior to planting or a herbicide is applied to kill forbs and volunteer wheat prior to drilling directly into the standing stubble (annual no-till). �307 .. ' -'--------,----B- E R T 34 C R B L 0 l -, Fig. 1. Height-density sampling locations in eastern Colorado, Spring 1986-87. Sampling was not conducted at sites 8 and 9 in 1987. �308 I -IJ ,..c: e H 0 c ''''; T I I Q) '-" ::l -IJ 0 H Q) e-, :> ::l H :3 (JJ 0 r-i r-i o til 4-< 0 Q) til c -'"0 I I' • '-" Q) ::l -IJ :>, 0 H Q) :> H ::l (JJ Q) . r-- 0 '"0 ~ r-i I \.0 00 0\ bDOO til ,...., r-i .,..; -IJ Q) 0 ,_.co r-i -IJ Q) co -IJ (JJ Q) ,_.e 0 U r-i ,.0 ,.0 :l UJ N · · eo ''''; ••• �309 Biennial No-till Winter Wheat - Fallow Cropping Rotation.--A system wherein herbicides are substituted in summer after harvest and/or during the subsequent spring as a replacement for tillage forb control within summer fallow. Conventional Winter Wheat - Fallow Cropping Rotation.--A system wherein discs, chisels, sweeps, or plows and other tillage implements are used to cultivate fallow ground to control forbs, loosen the soil, and prepare a seedbed during the summer fallow cycle. Tillage begins after harvest or is delayed until the following spring and is then continued as needed until wheat planting in fall. Ecofallow.--A crop system using a persistent herbicide, usually applied following wheat harvest, where corn or grain sorghum is slot planted directly into the standing stubble during the following spring (millet may be substituted for row crops). Conventional summer fallowing is usually conducted during the 3rd year prior to wheat planting in fall. Thus, 2 crops are harvested during a 3-year rotation. RESULTS AND DISCUSSION Quantity of Wheat Stubble for Nesting Wheat stubble represented about 75% of the available early spring pheasant nesting cover (assuming pastureland [20.4%] could be included as nesting cover) when approximately 1,000 mi2 was inventoried in extreme northeastern Colorado Tablelands in the mid-1960's (Snyder 1970). If short-grass pastures 'which usually offer extremely marginal nesting cover) were excluded, wheat stubble represented about 95% of the available nesting cover prior to onset of major green wheat growth. Starting in mid to late April, winter wheat rapidly becomes a co-dominant in importance for nesting with wheat stubble or replaces it since stubble is being lost to summer fallow tillage. By mid to late May green wheat becomes the dominant nesting cover. Wheat stubble and green wheat in combination represented about 90% of the available nesting cover for pheasants during a 1979-81 study in southeastern Sedgwick County (Snyder 1984). The amount of wheat stubble available in spring may be markedly altered by federal farm programs administered by the U.S. Department of Agriculture's Agricultural Stabilization and Conservation Service (ASCS) and by other factors. For many years wheat acreages have been reduced by annual "set-aside" programs. In 1986 and 1987 further reductions occurred because of the Conservation Reserve Program (CRP). Over 14% of eastern Colorado farmland had been committed to this 10-year retirement program by February 1987 and sign-ups will continue for several more years in most counties. The majority of these lands were previously farmed to winter wheat on a biennial cropping rotation. About 40% of stubble fields were tilled after wheat harvest in 1986 due to weed problems or other factors. Thus, the amount of standing stubble available in early spring 1987 was greatly reduced. This amount of late-summer tillage had not been noted in previous years in northeastern Colorado. However, the proportion of post-harvest tillage usually progressively increases from north to south across eastern Colorado. �310 In spite of these variables, wheat stubble remains the most abundant early spring nesting cover for pheasants in northeastern Colorado until green wheat attains adequate growth. Conventional summer fallow using tillage remains the major treatment of wheat stubble and represents over 90% of the area. Ecofallow has been rapidly gaining increased acceptance but its use in 1987 was restricted to <5% of the total area. Only about 1.9% of the fields in eastern Colorado were committed to the biennial no-till (wheat-fallow-wheat) cropping rotation in 1986 (Table 1) but the number of fields appeared to double in 1987. Some of this increase was possibly due to the cost share incentive payments farmers received under the ASCS administered Agricultural Conservation Program (ACP). A few farmers used annual no-till winter wheat farming in 1986 but area involved declined in 1987. Annual cropping conflicted with crop area restrictions which were mandatory if farmers were to receive payments for retiring cropland under ASCS administered federal farm programs. Quality of Wheat Stubble as Nesting Cover Weather-wheat Growth-Stubble Relationships.--Spring growth and quality of wheat is a product of soil moisture accumulated during the year of fallowing and the late winter and spring months when major growth occurs, and to a lesser degree, is a product of the departure of spring temperatures from long-term averages (Snyder 1984). wnen the mean April temperature (F) departure from the long-term mean was added to the l6-month accu~ulated· precipitation (in.), a direct positive relationship with 10 May wheat height (HDI) was ohtained. Inadequate samples were obtained in 1984, however, 1985-87 data provide continued evidence of this weather-wheat growth relationship (Fig. 3). The 1979-81 Sand Draw study (Snyder 1984) provided limited evidence that wheat stubble height was partially a product of wheat growth as influenced by weather. The precipitation-temperature index when compared with the 1984 and 1985 (South Republican) stubble heights closely fit this relationship (Fig. 4). However, subsequent 1986-87 stubble HDI samples, obtained from scattered locations in eastern Colorado (Fig. 1), showed deviation from data obtained in previous years (Fig. 4). Average HDI's for 1986-87 were lower than most preceding years (Fig. 5) even though the precipitation-temperature index was average or above. One possible explanation for the discrepancy between 1986-87 samples and previous data lies in changes in wheat varieties planted. Standard tall wheat varieties were planted in both the 1979-81 and 1984-85 study areas. However, a rapid shift to semi-dwarf varieties in east central and northeastern Colorado has occurred in recent years. Only 2% of wheat planted in 1978 was semi-dwarf varieties, this percentage increased to 50 in 1986 and 60% in 1987. Semi-dwarf varieties averaged <80 em taIlor about 33% shorter than standard wheat varieties (J. Echols, pers. commun.). These new, shorter varieties would be expected to yield shorter residual stubble (Figs. 4 and 5). Other Variables Determining Stubble Quality.--Most wheat fields appear uniform in height, however, farmers report many wheat heads are on shorter stalks forcing harvesters to cut lower leaving shorter stubble. The extent that this varies among farmers, wheat fields, wheat varieties, and years is unknown. Strong winds and light to moderate hail, produced by pre-harvest thunderstorms, �311 75 .1981 ~ :E ..- 0 60 Z 0 E o ._ I .1966· .1963 45 CJ .1966· 1980 W I ~1985-87 ~ w I 3: 30 Z W W a: CJ .1965 .1979 15 20 16 MONTH 30 25 PRECIPITATION + APRIL 35 TEMPERATURE Fig. 3. The relationship between whea t height on 10 Hay and an index combining precipitation (in.) over a l6-month (JanApr) interval plus departure of mean April temperatures from the long-term average, northeastern Colorado. Data include individual samples from 1963-64, 1979-81, 1985-87, and 2 samples for 1965-66 and 1968. �312 2.5 .1981 E -c 2.0 X W 0 ~ >ICi5 1.5 Z . W .1978 0 l- *1985 I CJ iIi :::r: 1.0 *1984 W -' • CD CD 1980 (HAIL) ::> I- *1986 en ~ 0.5 * w I 5:: 1987 .1979 o ~ 15 ~~ 20 ~ ~ 25 30 ~ 35 16 MONTH PRECIPITATION + APRIL TEMPERATURE DEPARTURE Fig. 4. The relationship between the whea t stubble heightdensity index and an index combining precipitation (in.) over a l6-month (Jan-Apr) interval plus departure of mean April temperatures from the long-term average, northeastern Colorado, 1979-87. �2.5 ............, EXCELLENT 2.0 ,-.... "d S '-" :>< ~(/) 1.5 z ~ GOOD r;-;-; A I E-< ~ ::r: ~~ ............ 1.0 ::r: FAIR r:-;-;-: ~ j:Q j:Q ~ (/) r.:: 0.5 E-< n ~ POOR .. <I; ~ ~ o 1979 1980 1981 1982 1984 1985 1986 1987 Fig. 5. Average height-density (dm) of wheat stubble within the Sand Draw (1979-82), South Republican (1984-85), and eastern Colorado (1986-87) study areas in relation to an arbitrary quality rating. w •..... w �314 may also lodge wheat forcing harvesters to cut lower. Wide variation among localities and years also occurs. Occasionally, wheat fields are intentionally harvested close to the ground so that straw can be baled for livestock or other commercial uses. Commercial fertilizers, used by most but not all wheat farmers, also impacts wheat growth and stubble quality as does soil type and quality. Eight of 21 stubble fields sampled in 1986 and 11 of 35 fields sampled in 1987 were farmed using no-till "herbicide" fallow methods during the respective years they were sampled. Few, if any, had been no-till fallowed previously so differences in stubble HDI resulting from past fallow treatment were not expected. Comparisons would need to be made between fields continuously subjected to no-till vs. conventional tillage farming before determinations as to the impact of farming method on stubble quality could be discerned. I assumed there were no significant HDI quality differences in stubble among treatments. Therefore, all stubble fields were combined and treated as samples from a single population. Wheat Stubble Quality-Wildlife Use Relationships.--The change to semi-dwarf wheat varieties has progressed rapidly and is expected to continue resulting in shorter wheat stubble than in the past. As a consequence, wheat stubble will become less attractive as early spring nesting cover for pheasants and some species of waterfowl (Anatidae). Under conventional summer fallow, tillage of stubble fields, which usually occurs during the s'prLng nesting season, will have less negative impact because fewer pheasant nests will have been started there. However, if the security of wheat stubble is enhanced using no-till methods, then shorter stubble means lower quality and reduced use by pheasants and other ground nesting wildlife. Nests placed in shorter stubble would also be less secure from predation. An arbitrary quality rating for pheasant nesting is provided (Fig. 5). Stubble HDI in 1986-87 was in the poor to fair range although stubble quality in most preceding years, when standard wheat varieties were used, had averaged from fair to good. The exception was in 1980 because of drought conditions in 1979 that severely impacted wheat growth. Wheat stubble has been used extensively by pheasants throughout much of the year for night-roosting, feeding, escape, protection from avian predators, and during blizzards and periods of deep snow. However, reduced stubble height, which may be more common in the future, will make cover conditions more marginal. Thus, pheasant survival will potentially be lowered and fewer hens will be present for nesting. The HDI quality ratings (Fig. 5) do not pertain to all wildlife species, most notably mourning doves. Personal observations, primarily during the 1979-81 Sand Draw Study, indicated that mourning doves used wheat stubble extensively for placement of first nests, especially in fields close to tree plantings. Dove nests typically were placed adjacent to a vertical clump of stubble usually in open or sparse stubble or stubble that had been undercut with a sweep plow. Soutiere and Bolen (1972) noted that most ground nests of doves had vertical cover on at least 1 side but overhead cover was not important within a burned Texas rangeland site. Doves were apparently attracted to the burn for nesting because of reduced litter and vegetation. Based on these observations and others in eastern Colorado rangelands, mourning doves would usually select against dense wheat stubble that retained minimal between-row �315 openings. Thus, the HDI rating at most dove nest sites would probably be low. Therefore, semi-dwarf wheat stubble fields which retain shorter more open stubble may be more attractive to nesting doves. These fields also provide open feeding sites for doves and other small avifauna. Little information is available in the literature to support the hypothesis that doves select against dense cover for nesting. Olson (1980) apparently conducted mourning dove nest searches in eastern Colorado after wheat stubble had been converted to fallow ground. Dove nesting there and in green wheat was reported as insignificant. Downing (1959) reported only 2 dove nests in 104 ha of wheat stubble searched soon after wheat harvest in northwestern Oklahoma; ground nest densities there were much lower than in nearby rangelands. Almost no dove nesting was noted in Illinois stubble fields (Hanson and Kossack 1963). It is assumed that wheat stubble there would be taller and more dense than in eastern Colorado. It also seems probable that dove use of stubble fields in eastern Colorado is highly variable based in part on stubble quality but also on the availability of other proximal life requirements. Quality of Nesting Cover in Annual No-till Fields.--Several northeastern Colorado fields were found that received an annual no-till winter wheat cropping treatment in spring 1986. Following wheat harvest in July 1985, these fields had been treated with a herbicide and fertilized or the latter was applied at the time of planting in September. Within the 5 sampled fields, height-density quality of wheat stubble and g~een wheat were listed separately and combined during i April sampling. Sites where wheat stubble was the dominant obstruction averaged 0.27 dm, those for wheat were 0.12 dm yielding a combined average of 0.18 dm. Thus, planted no-till wheat fields under annual cropping provided extremely poor nesting cover for pheasants but their value for first nests of mourning doves might be much better than in conventionally fallowed wheat fields. Growth of green wheat in these annually cropped fields was the same in 1986 as that in biennially cropped fields. Thus, their nesting quality tended to improve in the same time frame. Fall drilling into wheat stubble knocked nearly all of the stubble over or flattened it. However, the residual straw, both standing and flattened may have made annual no-till fields more attractive for nesting by pheasants, doves, horned larks (Eremophila alpestris), and other wildlife, whereas soil surface in conventionally fallowed wheat fields was nearly void of residual straw. Quality of Nesting Cover Under Ecofallow.--Slot planting of corn or grain sorghum within wheat stubble under the ecofallow (wheat-row crop-fallow) 3-year cropping system greatly reduced the quality of the remaining stubble as nesting cover. In both 1986 and 1987 mean indices averaged among fields were below 0.2 dm or they provided almost no standing concealment cover. Such fields would be of little value to nesting pheasants but might receive considerable use from mourning doves and other species with reduced cover requirements. Observations indicated post-plant HDI's were usually in direct relation to pre-plant stubble quality. The highest post-plant HDI obtained in 1986 was 0.26 dm from a field with a pre-plant HDI of 0.63 dm. In 1987 the highest post-plant HDI was 0.33 dm in a field where the pre-plant index was 1.1 dm. Observations indicatd a few fields existed containing considerably higher �316 pre- and post-plant HDI's. Where stubble fields contain much higher quality cover in bordering states to the east (where annual precipitation is greater), post-plant nesting quality would be expected to be much higher. Security of Wheat Stubble as Nesting Cover The primary reason wildlife managers have expressed an interest in new cropping systems involving winter wheat is because of their potential increased security ,for nesting. The insecurity of wheat stubble for pheasant nesting under conventional summer fallow has been documented (Snyder 1984). Eggs in only 1 of 18 nests hatched prior to tillage and the majority (11) were destroyed by tillage. Numerous other nests in the laying stage were suspected but could not be located and documented before they were destroyed. Stubble tillage progressed slowly from late April to early June along the tillage transect line during the 1979-81 Sand Draw study. As a consequence of this late tillage, 12 of 16 pheasant nests had advanced into incubation before being lost. Stubble tillage in 1986-87 progressed more rapidly (Fig. 6) and was comparable in timing to averages obtained from studies conducted in the 1960's and 70's within northeastern Colorado. Possibly fewer nests had advanced into incubation as a consequence but in 1987 numerous fields remained untilled into late May and early June. Surveys conducted in spring 1987 revealed that approximately 40% of the stubble fields had been disked or,undercut the previous year sometime after wheat harvest. Among fields tilled in spring, most were disked, however, individual farmers used different tillage implements including plows, chisels, and sweeps. In nearly all cases the majority Qf the standing cover was lost and the opportunity for a nest to survive intact was slight or nonexistent. The ecofallow cropping system, wherein a row-crop was slot planted directly into standing wheat stubble, appeared to be slightly more secure than conventional summer fallow tillage for ground nesting wildlife. Corn was planted beginning in late April or early May and most had been planted prior to when most pheasants would start incubation of clutches (Fig. 7). However, grain sorghum was usually planted from mid to late May which would be during the peak interval for pheasant incubation. Because of area restrictions for corn, grain sorghums, and wheat, millet planting has increased in recent years within eastern Colorado. Whereas, a nest had a limited opportunity of not being destroyed during slot planting of row-crops (probability <50%) millet was usually drilled in early to mid June (Fig. 7) yielding little chance that nests would not be destroyed. Most nests would be in incubation stages when lost. Some farmers apply fertilizer after their row crop has emerged which would cause further disturbance. A few also cultivate the crop to loosen the soil and to give the grain stalks additional support. Use of these practices does not appear extensive in northeastern Colorado. Since planting occurs directly into stubble in early fall, no disturbance occurs during the spring nesting seasn within annual no-till wheat. However, the quality of the cover over winter and prior to major wheat growth in late April is poor. �317 100 1986 80 ....... .. .. 60 ••• 1979-81 ...../ .. ... .... 40 20 ...• . ... o· o .....' o o 20 24 8 29 22 15 APR 5 HAY PROGRESSION OF 12 JUN STUBBLE TILLAGE Fig. 6. Progression of spring cultivation of wheat stubble fields during spring 1986 and 1987 compared with averages from previous intervals, northeastern Colorado. _,,' 100 r: 1987 " 80 o "-l e~ 60 c, :t: " ," CORN " MILLET GRAIN SORGHUM I" o u I I I I I e:z: "-l 40 u '""-lc, I I 20 I I ,J o 5 10 15 20 25 30 4 9 MAY PROGRESSION OF ROI,r-CROP PLANTIXG 14 19 24 JUN IN ECOFALLOI,r STUBBLE Fig. 7. Progression of row-crop planting stubble during 1986 and 1987, northeastern into ecofallow Colorado. wheat �318 The security of the biennial no-till wheat-fallow cropping rotation appears to be high and comparable to that of unfarmed covers. The only disturbance during the nesting season may be a late spring herbicide treatment. Since sprayers have wide booms, usually <10% of the ground will be contacted by machinery. Some nest abandonment might occur during spraying operations but its extent remains unknown. Most herbicides being used during spring applications have relatively low toxicity to wildlife or their eggs and little direct negative impact has been documented to date (Duebbert and Kantrud 1987). The Quality of Other Covers in Relation to Wheat Stubble Green Wheat.--The growth curve of semi-dwarf varieties of wheat may not be as steep as that for other wheat varieties, however, its value as nesting cover should not be markedly altered. Taller wheat varieties usually attain a HDI of 8-10 dm when headed. HDI values >3 or 4 dm are probably of little additional value for pheasants, the primary nesters in green wheat. Green wheat usually begins major growth in mid to late April and rapidly surpasses the HDI of wheat stubble in late April or early May (Fig. 8). Because of its uniform density and growth pattern, and lack of residual ground cover under conventional farming methods it receives little use by mourning doves or small passerine birds. Wheat planted directly into no-till stubble may be more attractive in early spring for doves and other species but this advantage is probably lost after growth >2.5 dm is attained. Wheat is a relatively secure nesting cover except when harvest occ~rs, normally during the first part of July in northeastern Colorado. Pheasants are the primary species affected because many hens are still incubating clutches placed there after previously being forced out of wheat stubble by tillage or predption (Snyder 1984). Native Grass.--Northeastern Colorado contains numerous small areas of unfarmed, ungrazed native vegetation within draws, odd corners, caliche knolls, right-of-ways, and other sites not suited for cultivation. These usually represent <5% of the available nesting cover but are moderately to highly secure from human disturbance. Dominant native grasses include blue grama (Boutelous gracillis), western wheatgrass (Agropyron smithii), sand dropseed (Sporobolus cryptandrus), and needle-and-thread (Stipa comata). Introduced annual bromes (Bromus spp.) often dominate in spring. The HDI quality of these tracts usually is low (Fig. 9) and if they surpass that of wheat stubble it isn't until late May when most stubble is already destroyed by tillage. Therefore, they are considered marginal in quality for pheasants. Short, high density vegetation within these tracts is not usually attractive to nesting mourning doves. However, these sites are considered essential to horned larks, western meadowlarks (Sturnel1a neglecta), grasshopper sparrows (Ammodramus savannarum), and lark buntings (Calamospiza melanocorys). A1falfa.--Numerous tracts in northeastern Colorado, planted to grass-alfalfa mixtures on CDOW leases and properties in the late 1970's and early 1980's, became strongly dominated by alfalfa. Sampling in 1986-87 revealed that alfalfa grew rapidly following a growth curve similar to that of wheat (Fig. 10) assuming average or better precipitation was received. Height was less than that of wheat but was adequate for nesting pheasants and the areas �319 5 ~~ ~6 I I I 4 I I e -e I 3 >- E-< >-< GREEN WHEAT (/) :z: c..J c I 2 E-< u >-< c..J = I·/HEAT STUBBLE 3 15 27 JUN HAY APR Fig. 8. He ight-densi t y (dm) progress ion of green whea t in relation to that of wheat stubble in 1986 and 1987, north- . eastern Colorado. 3 ..•..•. e "'" >•..... 2 E-< (/) :z: c..J c I t: G •....• c..J 87 0 J 15 APR L7 21 ':i MAY 2 14 JUN Fig. 9. Height-density (dm) pror,ression of native grass in relation to that of wheat stubble in 1986 nnd 1987, northeastern Colorado. �320 .,-,- . 8'3 , , ,, , .,~ "to >E-' H CIl :z: t<l ~~ 86 ~~ 2 ""E-'I == (.!) H t<l == WHEAT STUBBLE 0 3 IS APR 27 9 21 MAY 2 14 JUN Fig. 10. Height-density (drn) progression of alfalfa in relation to that of wheat stubble in 1986 and 1987, northeastern Colorado. �321 contained excellent dense foliage. Since a litter base was present along with considerable early spring diversity of height, its nesting value for pheasants was considered to be good. Past observations have shown that alfalfa usually tended to begin lodging by early summer and often lost most or all of its leaves during hot dry conditions. Late summer rains often stimulated regrowth. It also served as a food source for cottontails (Sylvilagus sp.) and plains deer (Odocoileus spp.), and provided brood habitat for pheasants. Loss of foliage and matting under winter snows has been a primary detractant to the value of alfalfa for wildlife, especially over winter. Old stands, >10-15 years of age, often become thin and codominated by annual bromes with reduced value for wildlife. Cool-Season Tame Grasses.--Tracts of unfarmed, ungrazed cool-season tame grasses were not abundant in northeastern Colorado during 1986-87. Nearly all that were located during the study were within CDOW leases or properties. Primary species included crested wheatgrass (Agropyron cristatum), intermediate wheatgrass (A. intermedium), and smooth brome (Bromus inermis). On the average, their early spring HDI quality ranked below that of wheat stubble, primarily because of over-winter lodging (Fig. 11). They slowly surpassed the HDI of stubble in mid to late April to attain moderate nesting cover value for pheasants by mid-May. Crested wheatgrass stands were open and sterile in appearance and of marginal value for most wildlife species. One tract containing smooth brome was within a grassed waterway "hich received above average moisture with resultant above average HDI. Past observations indicate this species routinely becomes sodded, nitrogen deficient, and offers marginal sterile cover on dryland sites in eastern Colorado within a few years after establishment. One bias within the sample was that most samples were >10 years of age and therefore of lower HDI quality and vigor than would be typified by younger stands. On the average, grass stands were older than alfalfa stands and some bias in HDI quality would be expected. Young stands of cool-season tame grasses «5 years of age) within CRP tracts would be expected to sustain higher HDI vigor approaching that of alfalfa but with a slower spring growth curve. Switchgrass.--The HDI quality of standing residual switchgrass, and in some tracts, other tall, warm season grasses, was much greater than that of wheat stubble or other sampled covers through early spring (Figs. 11, 12). Major new growth contributing to increased HDI was not attained until mid to late May. Average HDI indices/tract ranged from 1.1 to 3.2 dm within 5 tracts sampled in 1986 and from 0.5 to 4.1 dm within 8 tracts sampled in 1987. This illustrates the high variability among tracts. Younger plantings «10 years old) retained much higher HDI's and were potentially of high value for pheasant nesting, winter night roosting, and survival cover. Older stands retained considerable height diversity within individual tracts possibly increasing their attractiveness to passerine species. Prescribed burning or burning-tillage combinations could be used to restore HDI quality within the older stands, however, most were on private land. �322 3 STUBBLE 1) j LU ..! i JUN MAY APR Fig. 11. Height-density (dm) progression of switchgrass and tame grasses in relation to that of wheat stubble in 1986 and 1987, northeastern Colorado. . .... 5 o GREE:-I WHEAT :: e - . , ., ::," o 4 "'" 00 :, :, ., 3 .,; ALFALFA :, >- eCJl z W Q I 2 SIHTrHr.p·IC:C: e- = (.;) w ::: o j 15 APR 9 21 ~!AY 2 14 JUN Fig. 12. Height-density (dm) progression of major nesting covers averaged between 1986 and 1987, northeastern Colorado. �323 MANAGEMENT OPTIONS Wildlife managers have been urged to use winter wheat on CDOW properties in eastern Colorado when managing for pheasants and mourning doves (Rutherford and Snyder 1983). This is because it provides combinations of covers for nesting, brood rearing, night-roosting, and escape along with an excellent food source for pheasants, doves, and other wildlife. Wheat fields allow ease of movement by pheasants and create interspersions and diversity among perennial covers. Wheat fields provide both food and nesting cover whereas row crops provide only food. Wheat stubble stands well over-winter whereas many perennials lodge under snow. If winter wheat is to be of maximum benefit to wildlife, biennial no-till cropping should be used. However, farming practices including application of correct amounts of fertilizers and correct timing of herbicide application are essential to retain vigorous stands of both wheat and stubble. Tall wheat varieties and a minimum stubble height (12 in. or 3 dm) should be included in sharecropping contracts •• Sampling in 1986-87 revealed that wheat and stubble HDI was lower on some CDOW properties than on most adjacent private lands. Use of biennial no-till eliminates the existence of large bare fields over winter reducing snow drift and potentially increasing wintering wildlife survival. In spring and summer 100% of the land is in secure nesting cover and the vast amount of nesting cover available further increases nest security from predators. Division of Wildlife property technicians could readily farm biennially cropped no-till winter wheat on CDOW properties if they possessed necessary equipment and knowledge concerning the correct use and application of herbicides. Minimal manpower would be needed for herbicide application and planting. Fertilizer application and harvesting could be contracted to custom applicators and custom harvesters. Under this approach wheat stubble to 2 ft. tall (~6 dm) could be retained for yearlong use by wildlife. An alternate option for managing winter wheat on CDOW properties would be to require the sharecropper to apply short persistent herbicides in spring as a replacement for summer fallow tillage. The first tillage could then be delayed until mid-July or later, after the primary nesting season. Using this method, conventional rather than costly no-till drills could be used. Supplemental pre-plant fertilization would be essential to replace the nitrogen being used by decaying straw. Ecofallow or annual cropping of winter wheat should not be permitted on CDOW properties. Conventional summer fallowing should be discouraged along with stipulations as to wheat varieties used, stubble height retained, and fertilizer application. If conventional tillage is permitted, the field should be disced to reduce standing stubble, preferrably prior to 20 April or 1 May at the latest. Post harvest or spring sweep tillage should not be allowed. These stipulations should be written into sharecropping contracts. Little can be done to alter trends on private lands and a trend toward shorter, higher yielding wheat varieties is evident. Ecofallow is the primary new farming practice gaining acceptance in eastern Colorado. Biennial no-till or reduced tillage may result because of increased problems with annual bromes, jointed goatgrass (Adgilops cylindrica), and mustards (Brassicaceae) in wheat. �324 If crop surpluses and area restrictions ever become history, then a rapid trend toward an annual no-till winter wheat crop system may evolve in extreme eastern Colorado. At present there is no incentive in that direction. CONCLUSIONS There is evidence that wheat stubble HDI quality is deteriorating because of the rapid transition to semi-dwarf wheat varieties in eastern Colorado. This is not a concern for pheasant nesting under conventional summer fallow methods because nearly all nests placed there are subsequently lost to tillage or predation anyway. If it is less attractive for nesting, it may be better to prompt hens to place first nests elsewhere. The primary impact of shorter stubble is toward reduced fall to early spring survival of wildlife, primarily pheasants, because of greater exposure to blizzards and severe weather, and to increased exposure to avian predation. Reduced stubble HDI is primarily a concern for pheasant nesting under the bien;ial no-till winter wheat cropping system wherein stubble is not subject to tillage and therefore retains high security. Shorter stubble will retain lower HDI's and therefore be less attractive to nesting pheasants and nests placed there will be less secure from predation. In contrast, shorter, more open stubble may facilitate increased nesting use by mourning doves and some passerines. Reduced stubble HDI is of lesser importance for pheasant nesting under ecofallow but is a deterrent to winter survival of pheasants. Under annual cropping of winter wheat, reduced stubble HDI is of little significance since no undisturbed standing stubble is retained after fall planting. LITERATURE CITED Downing, R. L. 1959. Significance of ground nesting by mourning doves in northwestern Oklahoma. J. Wildl. Manage. 23:117-118. Duebbert, H. F., and H. A. Kantrud. 1987. Use of no-till winter wheat by nesting ducks in North Dakota. J. Soil and Water Conserv. 42:50-53. Hanson, H. C. and C. W. Kossack. 1963. The mourning dove in Illinois. Illinois Dep. Conserv. Tech. Bull. 2. Olson, T. E. 1980. Mourning doves and land use changes in Eastern Colorado. M.S. Thesis, Colorado State Univ., Fort Collins. 119pp. Robel, R. J., J. N. Briggs, A. D. Dayton, and L. C. Hulbert. 1970. Relationship between visual obstruction measurements and weight of grassland vegetation. J. Range Manage. 23:295-297. Rutherford, W. H., and W. D. Snyder. 1983. Guidelines for habitat modification to benefit wildlife. Colorado. Div. Wildl. Spec. Publ. 194pp. �325 Snyder, W. D. 1970. Pheasant hen harvest investigation •. Colorado Div. Game, Fish and Parks. Game Res. Rep" Apr il:3-81. 1984. Ring-necked pheasant nesting ecology and wheat farming on the -----High Plains. J. Wildl. Manage. 48:878-888. Soutiere, E. C., and E. G. Bolen. 1972. Role of fire in mourning dove nesting ecology. Proc. Tall Timbers Fire Ecology Conf. 12:277-288. Prepared by ~ a-UW ~ WarrenIf. snyaer Wildlife Researcher C ��31./ JOB FINAL REPORT Colorado State of: Project: 01-03-045 (W-37-R) 2 Work Plan: 21 Job Title: Dynamics of Cottonwood Regeneration Period Covered: Author: : Job Avian Research 01 January through 31 December 1987 Warren D. Snyder Personnel: C. E. Braun and W. D. Snyder, Colorado Division of Wildlife ABSTRACT Aerial photo interpretive methods were used by personnel of the Colorado State Forest Service (under contract) to obtain status and trends of cottonwoods (Populus spp.), shrubs, and other cover types along the lower portions of the Arkansas, South Platte, Colorado, and Rio Grande rivers in Colorado. A small segment of the South Fork of the Republican River was also inventoried. Aerial photos from earliest and most recent intervals yielded mean time lapse intervals of 25-37 years. Sampling intensity ranged from 15 to 27% using stratified random sampling procedures. Area occupied by cottonwoods declined >30% (P < 0.05) along the lower Arkansas River or at a rate of approximately l%/year, much greater than the 9% decline (p <0.10) along the South Platte and the 17.5% decline (P <0.10) along the Colorado River. In contrast, a slight increase (P>O.lO) In cottonwoods was recorded along the Rio Grande River. The South Platte retained a much greater area o;f cottonwoods per sample unit than any other river sampled. A marked trend toward more open stands of trees was noted along all rivers except the Rio Grande. The Colorado River had the youngest age structure among the rivers but it, like the other rivers, had a shift from younger to older trees over time. Thus, reproduction was not adequate to sustain existing stands of cottonwoods and most were in a decadent and declining status. Cottonwoods were nearly nonexistent along the sampled segment of the South Republican River in the 1930's but increased dramatically in recent decades. However, recent inventories indicate little natural regeneration of cottonwoods along this river. Tamarisk (Tamarix spp.) was replacing cottonwoods and willows (Salix spp.) along the Arkansas River whereas shrubs were declining along the South Platte and Rio Grande rivers but were apparently stable along the Colorado River. Declines in quantity of hay meadow occurred along all rivers from early to recent inventories, whereas dramatic increases were noted in quantities of agriculture and developed land. River channel declined dramatically along the lower Arkansas and Rio Grande rivers (p < 0.05), remained stable along the Colorado, and increased along the South-Platte. �328 Extensive snowpacks in the Colorado Rockies in 1982-83 and 1983-84 caused increased stream flows in 1983 and 1984 on most Colorado drainages. Flow volume along the South Platte and Colorado rivers was the highest recorded in recent history and caused flooding resulting in natural regeneration of cottonwoods, willows, and other species. Monitoring of intensive seedling transects along the lower South Platte revealed that extensive regeneration occurred but natural mortality, primarily because of desiccation, severely reduced seedling populations. However, some seedlings survived in most samples and rate of survival improved over time so that widely distributed natural regeneration of cottonwoods was evident into fall1987. In addition, flooding stimulated considerable reproduction of other woody species including green ash (Fraxinus pennsy1vanica) which showed evidence of gradually replacing cottonwoods along the lower South Platte. Little recent natural reproduction of cottonwoods was observed along the Rio Grande and Arkansas rivers. Altered stream flows, natural successional change, and other factors influencing reproduction of cottonwoods and willows were reviewed. Experiments with stem cutting planting of cottonwoods, willows, and other woody species into sites containing high groundwater tables yielded poor survival along the South Platte, South Republican, and Arkansas rivers. Several factors contributed to poor survival, but fluctuating groundwater levels were the primary deterrent. Poor survival and planting difficulties made stem cutting a questionable management tool in most sites. Alternate methods of stimulating reproduction or replacing trees, shrubs, and v-ines are summarized. Recommendations were provided concerning future inventory and monitoring of riparian habitats and wildlife populations in combination to fully assess impacts of changing environments. �329 RECOMMENDATIONS 1. Inventories of riparian habitats along the San Juan, Dolores, Gunnison, North Fork of the Gunnison, White, Yampa, and other rivers should be conducted in the near future on a priority basis. Limited monitoring should be extended to lower portions of tributary streams in eastern Colorado including the Purgatoire, Big Thompson, Cache la Poudre, and North Fork of the Republican River. Where habitat deterioration appears greatest, as along the Arkansas River, monitoring should be more frequent and sites where threatened or endangered wildlife occur should be closely monitored. Sample size should be increased in future surveys of the Arkansas River and monitoring should be extended to and potentially beyond Pueblo Reservoir. Inventories of status and trends along the Rio Grande, Colorado, and South Platte rivers should be conducted again in the 1990's. Colorado Division of Wildlife personnel should work closely with Colorado State Forest Service personnel to ensure that the oldest and most recent aerial photos available are used in sampling. 2. Photo interpretive monitoring of previously established 1.61 km sample units as to status and trends of key vegetation types, as used in this study, should be continued at intervals of 10-15 years. These data should .be supplemented with permanent transects within each sample unit. Standardized sampling procedures that yield indices of vertical and horizontal diversity (Anderson et ale 1978), composition of woody species, and composition of herbaceous vegetation (percentages of annual, biennial, and perennial forbs, and annual and perennial grasses) should be used. 3. Census of key stenotopic wildlife species (Svoboda and Graul 1980, Miller 1985) (density/sample units) should be periodically conducted (3-5 yrs) following Fitzgerald (1978), and Sedgwick and Knopf (1986, 1987). Replicates over time demonstrate trends and impacts of habitat changes along major rivers. 4. Inventories of the quantity and quality of riparian habitats in important tributary drainages are needed, especially in grazed low elevation locations. 5. Pothole blasting (Hopper 1978), use of heavy equipment, of other methods of creating small basins or- ditches within the flood plain could be used to promote establishment of cottonwoods, willows, and other phreatophytes where high «1.5 m) groundwater tables exist. Irrigation, either by ditching and flooding or sprinkling could be used but would need to be sustained to retain moist soil at or near the soil surface throughout the growing season for at least 2-3 years and probably longer. Relative availability of water, equipment, and manpower may dictate which, if any, approach is feasible in a specific location. 6. Use of stem cuttings of phreatophytes should not be completely discounted even though only poor survival was attained during this study as it has been used economically and successfully in many locations. However, monitoring of groundwater stability, and soil quality and structure is recommended for a year in advance of planting. �7. The groundwater level in riparian zones along small stable streams (e.g., below Bonny Reservoir) could be raised by using small metal check dams placed at frequent intervals along the stream. This approach combined with soil disturbance may be sufficient to enhance natural regeneration of phreatophytes in many locations. 8. Seepage areas often occur in locations between irrigation canals and the river and some have relatively stable water conditions. Some sites may have considerable value for establishing cottonwoods, willows, or other phreatophytes using either stem cuttings or rooted seedlings. 9. Planting of rooted seedlings of selected tree, shrub, and vine species obtained from nursery stock appears more practical than use of stem cuttings. However, neither method could be used over extensive areas. Individual seedlings could be planted in desired patterns to enhance vertical and horizontal diversity using polypropylene mulch placed 1-2 m around individual plants to reduce weed competition and retain soil moisture. Plastic tree protectors to reduce browsing by deer, rabbits and other wildlife is essential. 10. Livestock grazing of riparian sites, especially when intensive and/or during the grow~ng season is highly negative to both cottonwood and willow reproduction, and to the herbaceous understory. Grazing should be excluded when possible and, if permitted, should be restricted to light , intensity during the late winter dormant season. 11. Plowing and discing of disturbance tillage strips should be used, especially in ecotones between shrubs and/or trees and perennial herbaceous cover, to enhance the food base for wildlife and to increase horizontal diversity. These strips should be tilled early each spring or in alternate years' to retain seed producing annuals. Fireguards, surrounding grass-dominated meadows can serve as additional disturbance tillage strips. 12. Guidelines for conducting controlled burns within riverbottoms are: Burns should be limited to small tracts « 2 ha) in higher elevation sites dominated by grasses'. Efforts should be made to protect trees, and shrubs, especially those that have high quality as winter r'estLng sites for wildlife <, DiiiCing of fireguards, backfiring; use of wetting agents, and other methods should be used to reduce fire intensity.' . 13. Beaver (Castor castor) are <?- natural part of riparian ecosystems and should not be eliminated. However, trapping is suggested when needed to prevent overpopulation and extensive damage to streamside cottonwoods. �331 DYNAMICS OF COTTONWOOD REGENERATION Warren D. Snyder INTRODUCTION The cottonwood-willow riparian habitat is the most important ecosystem for wildlife in Colorado based on diversity (species richness) and density (Beidleman 1978, Crouch 1961, Fitzgerald 1978, Graul 1977, Hoover and Wills 1984, Schrupp 1978). Statewide, the cottonwood riparian ecosystem is used by 283 species of vertebrate wildlife, by far the highest number of any ecosystem. Most of these species are present because of food-cover associations, not because of associated aquatic environments. Fitzgerald (1978) listed 129 species of birds, 28 mammals, and 20 herpetofauna as occurring in the South Platte cottonwood riparian zone based on data from his field work and that of Beidleman (1954) and Crouch (1961) in northeastern Colorado. The cottonwood-willow riparian ecosystem is especially important because it comprises such a small portLon of Colorado, especially within the High Plains of eastern Colorado. There it is estimated to occupy <0.5% of the total land area. Statewide, cottonwoods occupy <0.2% of the total land area (Bottorff 1974). Riparian habitats have also been centers of man's act~vities since Colorado was first settled and before. Highways, railroads, towns and cities, reservoirs and irrigation diversions, stream channeling, diking, gravel mining, and farming are among the impacts that usually degrade this habitat for wildlife. In addition, intensive livestock grazing is a major impact especially along nearly all of the smaller streams or intermittant washes. Along with these problems man has introduced invader species including tamarisk (Tamarix spp.), Russian-olive (Elaeagnus angustifolia), and Canada thistle (Cirsium arvense). This study was initiated in the early 1980's within the Division's Nongame Research group which was later incorporated into the Avian Research group. The primary basis for the study was concern that cottonwoods were not being sustained by natural reproduction and were deteriorating. This concern has not been restricted to Colorado, but is widespread especially in western United States. Numerous studies, conferences, and symposia (Johnson and Jones 1977, Swanson 1979, Nelson and Peek 1981, Simons et ale 1981, Schmidt 1983, Hoar and Erwin 1985, Johnson et ale 1985) attest to this concern. P. N. OBJECTIVES 1. Quantify changes in stand density and changes in area of riparian cover types over a recent time span approximating 30 years within the South Platte, Arkansas, and South Republican (below Bonny Reservoir) rivers in eastern Colorado, the Rio Grande River in the San Luis Valley, and the lower Colorado River in western Colorado. Analyses and evaluations will be based on aerial photo interpretation by the Colorado State Forest Service (under contract). �332 2. Document conditions conductive to natural regeneration and survival of plains cottonwoods (Populus sargentii) and willows, including site characteristics and frequency of occurrence, in streamside riparian habitats of the lower South Platte River in northeastern Colorado following high water conditions in 1983 (potentially also in 1984). 3. Test methods for establishing woody vegetation within streamside riparian zones where natural propagation cannot be expected. These include: (a) using stem cuttings of dormant specimens and planting them so their bases extend into the groundwater as a method for propagation of selected tree, shrub, and vine species for use where natural propagation no longer occurs, (b) create exposed bare ground sites using tillage or scarification for natural establishment of plains cottonwoods, peachleaf willow, or other woody vegetation present near the site. ACKNOWLEDGMENTS Preliminary study planning and design were conducted by G. C. Miller, former Wildlife Researcher, under the supervision of W. D. Graul, former project leader' within the Nongame Research group. They coordinated contract agreements with T. Owens and D. Teska, of the Colorado State Forest Service; the latter personnel did the actua~ photo interpretive inventory. In 1983 the study was transferred to the Avian Research Section of the Colorado Division of Wildlife under the direction of C. E. Braun, Project Leader. D. C. Bowden, consulting statistician, assisted. in preliminary design as well as conducting major analysis of findings. Personnel assisting in field data collection included J. F. Corey, M. Stanley, J. Palic, and A. Palic. METHODS Pertinent literature was reviewed concerning facets of riparian ecology including past inventory methods for cottonwoods, stem cutting techniques, and ecology of natural cottonwood - willow regeneration. Inventory A stratified random sampling method was developed in consultation with D. C. Bowden, contract statistician, to inventory downstream portions of several major rivers in Colorado. River mile (1.61 km) sampling units were located with an electronic planimeter in mid channel. Strata were selected and river mile sample units were randomly selected for inventory. Sampled rivers included the South Platte, Rio Grande, Colorado and Arkansas (Fig. 1). In addition a non-random segment of the South Fork of the Republican River was selected. Personnel skilled in aerial photography interpretive methods for inventorying stands of trees within the mapping section of the Colorado State Forest Service (CSFS) were contracted to conduct inventories. They obtained aerial photos from the earliest and most recent intervals they could find for use in assessment of changes among cover types and stands of trees. A 25-year separation between the earliest and latest photography was the minimum interval used. A vegetation classification system (Table 1) was developed in discussions between cnow and CSFS personnel. Characteristics of inventoried segments, sampling intensity, and other criteria varied among rivers (Table 2). �r: -------------- _ -1 GRANO JUNCTION ~-,~ I I I , ,,I I I • I J • •• •/ LAKE PUEBLO CITY I --- I COLORADO ........ I ~---------------------Fig. 1. Distribution of cottonwoods (Map courtesy of C. C. lJiller) --------...:.---- PLAINS RIO COTTONWOOD GRANDE NARROWLEAF -- COTTONWOOD COTTONWOOD J I ---------- by species along major river drainages in Colorado. w w w �334 Table 1. Classification system and codes used by the Colorado State Forest Service during inventory of vegetation types along rivers in Colorado. Cover or vegetation type Symbol Hay meadow/emergents Grassland Shrubs communities (upland, mesic, & wetland) Conifers Agricultural Developed River Unvegetated/sandbar = River Channel Lakes, ponds, reservoirs Cottonwoods (plus other tree species) Size-age classes <1.5 dm - dbh «6") 1.5 - 3.8 dm - dbh (6-15") 4.1 - 7.6 dm - dbh (16-30") >7.6 dm - dbh (>30") Crown density classes (canopy cover) 10-34% 35-55% >55% H GR S J AG D R NV R C I" 2 3 4 A B C aMinimum polygon size for all types was 1 ha. Table 2. Sampling intervals (X years), linear river distance (km), sampling intensity (ha, %), number of sampling strata, upper and lower elevations (m), and upper and lower K daily stream flows (m3s) along segments of 4 rivers in Colorado. Variable Arkansas ~ sampling intervala Distance sampledb Area sampled % sampled Strata Elevations - upper lower Stream flows - upper lower 31.2 241.3 3,433 15 3 1,372 1,036 26.6 3.2 River South Platte Colorado 36.4 263.7 5,443 18 4 1,372 1,066 21.8 15.1 25.0 167.3 1,826 20 4 1,829 1,372 100.5 175.5 Rio Grande 36.8 117.4 3,263 27 3 2,438 2,286 25.3 7.0 aAerial photos were primarily from 1940's (early) and 1978-80 (late) except along the Colorado River where early photos were from 1951-57. bLinear study area distance was measured at the center of the river channel. �335 Field trips by CSFS personnel were used to verify deliniation accuracy on all rivers. It was not possible to distinguish between tamarisk and willow species from available photography. Therefore, areas and points within them were selected from aerial photos and among strata for field sampling. Shrubs within 43 0.004-ha (1/100 ac) circular plots were identified as to species, and the percentage of shrubs by species was calculated. Analysis of variance and paired t tests were used in preliminary analyses of changes within cover type and trees stands over time and among strata. D. C. Bowden, consulting statistician, was contracted to conduct a more detailed analysis of cottonwood age class and canopy cover changes among strata. Natural Reproduction Conditions conducive to natural regeneration and survival of plains cottonwoods along the South Platte River were documented using 2 primary approaches. The locations of new cottonwood seedlings were marked along several accessible areas of the lower South Platte including both grazed and ungrazed sites following 1983~84 high stream flows. Two dozen individual intensive transects, up to 25-m in length were randomly selected among these locations. The transect ends were marked with steel posts and, during sampling, a tape marked at l-m intervals was placed between the posts. Within high density seedling stands, seedlings were counted within a 0.09-m2 sampling frame at l-m intervals along 1 side of the tape during early fall intervals from 1984 through 1987. Within low density seedling stands, the tape bisected a l-m wid~ continuous sample strip sampled at l-m intervals. As seedling stands evolved from high to low density status, the procedure was adjusted from 0.09-m2 to l-m2 samples. Stands were monitored to document the primary factors (desiccation, grazing, etc.) responsible for cottonwood attrition. The relationship between seedling survival and water table level, and water level fluctuations was assessed. Site characteristic information recorded at each transect included: (1) location (edge of gravel bar, side channel, main channel, etc.), (2) overstory, (3) competition from other vegetation, and (4) livestock grazing season of use and intensity. Frequency of cottonwood seedling occurrence was sampled at 30 random transects along the lower South Platte River in northeastern Colorado. Odometer readings were used to randomly select starting points along accessible sides of the river; random selection among compass bearings toward the river was used to determine direction. Locations where the distance from the river channel to the edge of the flood plain was <100 m were excluded. A l-m2 plot was used as the sampling unit and seedlings of cottonwoods and other tree species were counted as present or absent at 5-pace intervals along the transect. Sampling was conducted in early fall each year from 1984 through 1987. Year of seedling establishment was recorded if it could be determined. The dominant cover type present in all sample frames was recorded where tree seedlings were absent. Categories included sand bar, bare ground, litter, low shrubs, tall shrubs, vines, annual grass, perennial grass, annual forbs, and perennial forbs. �336 Woody Cover Propagation Procedures One or more locations within several sites were selected to receive stem cutting treatments. These included the South Platte Wildlife Management Area (SPWMA) (Tamarack), Duck Creek, and Sedgwick Bar properties along the South Platte River, The South Republican Wildlife Area (SRWA) below Bonny Reservoir along the South Fork of the Republican, and the Rocky Ford, Escalante, Purgatoire, and John Martin properties along the lower Arkansas River. After preliminary extensive trials, more intensive procedures were concentrated at SPWMA and SRWA. Groundwater levels and fluctuations were monitored at stem cutting locations using perforated 3.B-cm diameter plastic pipe inserted into the water table. Monitoring of water levels and fluctuations occurred primarily during successive growing seasons. Stem cuttings of cottonwoods, several species of willows, and other selected trees, shrubs, and vines were primarily obtained from wild stock within CDOW properties. Most stem cuttings were treated with a root stimulator (indole 3 - butyric acid). Preparation of planting stock, pruning, treatment, and placement generally followed procedures described by McCluskey et al~ (1984) and Swenson and Mullins (1985). Holes were dug for placement using a tractor-mounted power augers approximately 1.0 and 2.5 dm in diameter to depths approximating 1-1.2 m. Hand augers were used to penetrate to greater depths and, in some instances, a rod or pipe was driven into the soil to facilitate placement of cuttings. Methods used in 1986 included inserting a l-dm diameter plastic pipe into a hole dug with a power auger. The pipe was repeatedly pushed down as sand was extracted with a hand-operated ·sand auger permitting stem cutting placement to greater depths into the water table. Within some 1986 test sites, competing vegetation was removed by tillage and, after stem cutting placement, the site was overlaid with 4 mil. black plastic sheeting and wood chips. Stream Profile Sampling A map of the South Republican River in Yuma County was gridded at 400-m intervals to bbtain stream profile data. Random selection among intervals permitted selection of 12 points respectively below and above Bonny Reservoir. A 30-m tape marked at l-m intervals was placed level across the stream and vertical distances from the tape to the stream were obtained at l-m intervals. A transit and rod were used to obtain stream profile samples along the Arkansas River. Samples were obtained at accessible lbcations within previously selected inventory random units. Twelve locations above and 12 locations below John Martin Reservoir were sampled. A line was placed across the channel facilitating sampling at I or 2-m intervals. Channel width and vertical distance from river level to cottonwood tree bases were also obtained. Evaluation of Controlled Burns Evaluation of controlled burning within the South Platte riverbottom included late May and early September post-burn inventory of survival and regrowth status of trees and shrubs within burns conducted by CDOW management personnel �337 in early spring 1985 and 1986. Visual obstruction sampling (Robel et ale 1970) of herbaceous vegetation during pre and post-treatment late winter intervals was conducted along random transects within the 1986 burns and proximal controls. Herbaceous Vegetation Sampling within Disturbance Tillage Sampling of dominant herbaceous vegetation within fireguards and other disturbance tillage strips was conducted during September 1986 and 1987 within CDOW properties along the South Platte River. Locations of starting points for transects were randomly selected. The dominant vegetation within 1-2 m2 samples was recorded at 5 or 10 step intervals. Scientific names of plants follow Harrington (1954), Scott and Wasser (1980), and McGregor (1986). RESULTS AND DISCUSSION Inventory Results of the inventory conducted by personnel of the Colorado State Forest Service were reported earlier (Snyder 1984, 1986a, b; 1987). These data were further examined in attempts to understand probable-reasons for changes in quantity, density, and ages of stands of cottonwoods and their potential impacts on wildlife. Arkansas River.--Historically, the Arkansas Riyer Valley through much of western Kansas and eastern Colorado was treeless based on accounts by early explorers (Lindauer 1970, Nadler 1978, Athearn 1985). One large open stand of mature cottonwoods, called Big Timbers, existed near the present town of Lamar extending upstream for 6.4 to 48 km (reports conflict). No underbrush was present. Trees also reportedly lined the riverbanks in the vicinity of Pueblo, but many other stretches along the river were treeless. Several small canals diverting irrigation water from the Arkansas were constructed along the valley in the 1870's and 1880's and priorities of 8 ditches were adjudicated by 1884 along the lower Arkansas (Nadler 1978). The Sante Fe Railroad was completed in 1873 which set the stage for development of towns along the valley. During the 1880's and 1890's larger and longer canals were constructed, funded by eastern investors, and by 1895 20 major diversions had been developed. Development of irrigation and intensified farming along the valley continued in the early 1900's including construction of several off-stream reservoirs and use of natural basins for water storage. The amount of land under irrigation in those early years is unknown but Nadler (1978) documented that irrigated lands along the valley declined from 220,725 ha in 1936 to 197,600 ha in 1969. John Martin Reservoir, a large main-stream impoundment, was constructed in the late 1940's and began storage of water in 1949. However, due to downstream irrigation demands the reservoir remained dry through much of its existence. Pueblo Reservoir, constructed above the city of Pueblo, began storage of water in 1974 (Fig. 2). Ten diversions of West Slope waters occurred between 1880 and 1972 (Nadler 1978) with the most recent diverting a considerable amount of water from the Frying Pan River. �SOUTHEASTERN COLORADO N en ct: en z -c ~ ------.--------------- J NEW MEXICO , OKLAHOMA ~ C') r" Fig 2. stratas Arkansas (I). River drainage showing major reservoirs, portion inventoried (__ ), and �339 The Arkansas River drains about 15,534 km2 of mountainous area and is fed by numerous tributaries draining an additional 50,227 km2 between Pueblo and the Kansas-Colorado border (Fig. 2). The semi-arid shortgrass plains of southeastern Colorado are dominated by shallow soils and marginal vegetation. Thus, runoff from infrequent but occasionally heavy rains can cause flooding. Major floods have been infrequent, occurring in 1909, 1921, and 1965. Lesser floods or high run-offs occurred in 1903, 1914, 1915, 1942, 1947, and 1956. Mean annual discharge peaked in the early 1920's, early 1940's, to a lesser extent in the mid 1960's (Nadler 1978), and increased flows were again noted in the 1980's. Nadler (1978) provided data showing the bankfull width of the Arkansas River in the LaJunta-Las Animas area (Fig. 2) averaged about 175 m in 1870 increasing to 215 m in 1892-1926. By 1952 the channel averaged 46 m in width and only 32 m by 1977 or about 15% of the 1892-1926 mean width. An average width of 87 m was obtained for 12 sites in 1986 between Pueblo and Las Animas. In western to central Prowers County the river was historically wider averaging 215 m (1870), 355 m (1892), but only 145 m by 1926. Mean width in 1952 was 54 m and shrinkage continued as the river was impacted by John Martin Reservoir. Stream widths downstream from the reservoir in 1986 averaged 35 m, about 10% of that in the late 1800's. The Arkansas River was originally much wider (375 m in 1870, 335 m in 1892) in eastern Prowers County but had declined to 137 m by 1952. Dramatic shrinkage has continued because widths ranged from 24 to 50 m in that vicinity in 1986. Apparently the river flowed intermittantly prior to being impacted b~ man, drying completely in late summer and fall. Continuous flows began in the early 1900's because of return flows and seepage from irrigation. Nadler (1978) reported that the river originally was nearly straight with numerous small shallow channels and islands. With dewatering and altered stream flows, the river has become more meandering and confined to a single channel. Arkansas River flow (K m3/s) (U.S. Geol. Survey \~ater-Data Reports) averaged annually since 1914 show flows have fluctuated considerably among decades (Table 3). At Nepesta, east of Pueblo, recent average flow rates were less than in earlier decades with no interval of clear decline evident. At Lamar, reduction in flow in recent decades is more evident. Stream flow rates along the Arkansas diminish rapidly due to irrigation diversions along the river. At Avondale, east of Pueblo mean daily flows averaged over 14 years from 1965 to 1984 were 26.6 m3/s. Downstream near Las Animas, flows averaged 6.0 m3/s. Flows from John Martin Reservoir were slightly higher at 7.3 m3/s due to supplemental water from the Purgatorie River. At Lamar, daily flows averaged 3.2 m3/s compared to 5.7 m3/s near the Kansas-Colorado Border. Photo interpretive inventory sampled 3,433 ha within 36.7 km of a 250-km segment of the lower Arkansas River beginning about 36.7 km east of Pueblo and continuing to the Kansas-Colorado Border (Fig. 2). John Martin Reservoir (25 km) was excluded from sampling. The 1st of 3 strata contained 50 km, the 2nd and 3rd, 100 km each above and below John Martin Reservoir respectively (Fig. 2). Average sampling intensity was 14.7%. Original year aerial photos ranged from 1940 to 1955 and all recent photos were from 1980 yielding average time intervals of 25.7, 29.1, and 38.6 years, respectively for the upper, middle and lower strata. The overall mean interval was 31.2 years. �340 Table 3. Mean stream flow rates (m3/s) at 10-year intervals at measuring stations along the Arkansas, South Platte, Colorado, and Rio Grande rivers, Colorado. Arkansas Period Nepesta 1891-1900 1901-10 1911-20 1921-30 1931-40 1941-50 1951-60 1961-70 1971-80 1981-86 22.8 21.0 14.1 23.6 17.4 17.9 17.9 28.0 South Platte Lamar Kersey 7.1 11. 7 2.9 8.7 1.6 3.1 1.4 4.2 19.0 21.3 25.5 13.2 23.0 16.0 21.3 30.5 36.6 Julesburg 14.8 15.4 14.3 7.6 15.1 9.2 12.3 17.9 28.2 Colorado Glenwood Springs Cameo 84.4 74.5 92.5 65.9 63.6 58.0 Rio Grande Del Norte Alamosa 23.5 26.9 31.1 31.1 21.1 28.6 19.9 23.0 22.7 24.1 108.6 118.6 105.6 101.7 116.7 146.6 12.9 11.3 3.9 7.7 3.1 4.6 5.9 Overall changes in vegetation types and comparati·ve changes among strata were variable (Tables 4, 5). Hay meadow and grassland both declined at modest rates from early to recent sampling. The majority of the decline in hay meadows occurred within the middle stratum whereas grassland declined markedly in the lower stratum apparently giving way to cropland (Table 5). Agriculture or cropland increased dramatically (p < 0.005), especially in the lower stratum: Developed land, while comprising only 1-2% of the total, nearly doubled in quantity (p < 0.005). Table 4. Proportions and changes (ha/l.6l km) in vegetation types over a 3l.2-year interval along the Arkansas River, southeastern Colorado (1940-80). Vegetation Cottonwood Shrub Hay meadow Grassland Agriculture Developed River channel Standing water *p < 0.05. haiL 61 km Early Recent 29.42 39.07 34.17 24.98 1.54 1.66 25.12 0.10 20.41 47.32 29.40 22.52 19.38 3.30 12.62 1.05 Change ha % .t. -9.01 8.25 -4.77 -2.46 17.84 1.64 -12.50 0.95 -30.6 21.1 -14.0 -9.8 1,155.2 98.8 -49.8 950.0 2.90* 1.78 0.87 0.66 3.00* 3.00* 5.45 1.10 �341 Table 5. Average change of vegetation types (ha/l.6l km) among strata from early to recent intervals along the Arkansas River, southeastern Colorado. Vegetation Upper Stratum Middle Cottonwood Shrub Hay meadow Grassland Agriculture Developed River channel -9.00 4.39 -2.17 4.85 7.37 0.93 -9.77 -7.30 9.94 -9.89 -1.28 11. 77 3.39 -6.86 Lower F value -11.20 9.37 0.41 -10.23 34.60 0 -22.10 0.17 0.12 0.29 1.28 1. 73 0.87 6.41* *p < 0.05. River and vegetated (sandbars and mudflats) were combined for analysis since differing water levels between photo periods could bias results.· There was a 50% decline in river channel (p < 0.05) with the greatest decline occurring in the lower stratum below John Martin Reservoir (P<0.05) (Tables 4,5). These dramatic declines in channel width supports Nadler's (1978) findings and are readily discernable from inspection of aerial photos. Tamarisk has invaded much of the former channel within the lower stratum. A channel width averaging 35 m in the lower stratum differed (P <0.05) markedly from the 87 m mean width upstream from John Martin Reservoir~ Another concern was whether the river channel had deepened appreciably below John Martin Reservoir in relation to upstream areas. However, dense tamarisk stands along the river made it extremely difficult to obtain stream profile samples comparing upstream and downstream sites based on a standard 100-m width because transit-level sightings could not be conducted through the dense growth. Stream profile samples that varied in length, but averaged 98.2 m wide, were conducted on 12 upstream samples. In comparison, 9 downstream sites averaged 97.2 m wide. The average of the 8 deepest profile measurements from upstream samples was 17.8 dm whereas the average downstream profile was 23.1 dm (t = 2.93, 19 df, P < 0.05). Thus, there was evidence that the downstream channel had deepened. Personnel of the U.S. Corp of Engineers at John Martin Reservoir provided historic degradation data from 13 sample points lying between the Reservoir and Lamar. Graphic presentations of those data showed that at several points within a few km of the Reservoir, a narrow channel had deepened about 0.61 to 1.2 m beyond the original channel depth. However, further downstream near Lamar deposition had occurred filling much of the original channel leaving a narrow channel at about the same elevation as that present in 1943-44 when monitoring was initiated. Nadler (1978) presented data showing the same type of deposition had occurred further downstream. A major flood occurred immediately below John Martin Reservoir and downstream in 1965 when the spillway was opened and Muddy Creek, Clay Creek, Butte Creek, and other streams rampaged and undoubtedly deposited considerable sediment in sites containing tamarisk and other vegetation. �342 The vertical distance from river water level to the base of nearby cottonwoods was measured within sampling sites at several locations upstream and below John Martin Reservoir. Trees were not present for sampling at several downstream locations so sample size was reduced. The average vertical distance from water to tree base among upstream samples was 13.6 dm contrasted to an average of 20.4 dm among downstream samples (~< 0.05). Occupancy by cottonwood stands decreased 31% in the inventoried areas or approximately l%/year with a mean loss of 9.0 ha/l.6l km during the interval (p = 0.002, Table 4). The decrease was greatest in the lower stratum (p = 0:029, Table 5). Initially, cottonwoods occupied 18.9% of the inventoried riverbottom but declined to 13.1% occurrence during the recent sample. Occurrence of trees was strongly skewed toward the upper stratum (Table 6, Fig. 2) where they declined from 52.3 to 43.3 ha/l.6l km during the sample interval. Within the 2nd stratum, trees initially occupied only about one-half (24.1 ha/l.6l km) the area of occurrence as in the upper stratum, and declined at a much greater rate to 16.8 ha/l.6l km. In the lower stratum below John Martin Reservoir, trees initially occupied only about one-third of the area and by the recent inventory had declined to 5.4 ha/l.6l km (Table 6). It is probable that cottonwoods were not highly abundant within the lower stratum because of the rapid invasion of tamarisk in the early 1900's. Table 6. Area occupied by cottonwoods (X ha/l.6l km) from early to recent sampling intervals among strata and rivers, Colorado. Stratum 1 2 3 4 Arkansas Early Recent South Platte Early Recent 52.3 24.1 16.6 63.7 47.2 68.2 72.3 43.3 16.8 5.4 50.6 56.9 55.0 72.5 Colorado Early Recent 3.6 38.6 12.6 14.9 0.3 31.6 11.9 13.1 Rio Grande Early Recent 23.7 48.1 8.0 29.6 51.8 6.9 aStratum 1 is the stratum located furthest upstream on all rivers. Decreases in occupancy were noted in all size-age classes of cottonwoods from early to recent inventories, but were most significant in the 4.1-7.7 (-58%, P = 0.05) and >7.6 (-15%, P = 0.0004) classes (Table 7, Fig. 3). Size-age class distributions of the cottonwood-dominated stands were similar during the 2 inventories with a preponderance in the 1.5-3.8 and 4.1-7.6 size-age classes (Fig. 3). Open stands of cottonwoods dominated the forested areas in both inventories (Fig. 3) and did not change substantially in occupied area (-3%, ~ = 0.36). However, stands of intermediate canopy closure decreased by 59% in area (p = 0.003) and closed stands declined by 51% (~ = 0.50). �343 AGE CLASS (DM -DBHI 14 12 ~ > 7.6 (LZ;] 4.1-7.6 ~ 1.5-3.8 10 ••• . to < 1.5 8 6 4 2 o EARLY RECENT 10-34' EARLY RECENT 36-55 EARLY RECENT <55 CANOPY COVER Fig. 3,~ Early to recent changes/sample (X ha/1.6l classes (dm-dbh) and canopy cover (%) of cottonwood lower Arkansas River, southeastern Colorado. km) by size-age stands along the �344 Table 7. Changes by age-class and canopy cover (~ ha/l.6l km) of cottonwood stands over a 3l.2-year intervala along the Arkansas River, southeastern Colorado, 1940-80. Age-class (dm-dbh) <1.5 Canopy cover (%) 10-34 35-55 >55 Subtotal 1.5-3.8 10-34 35-55 >55 Subtotal 4.1-7.6 10-34 35-55 >55 Subtotal > 7.6 10-34 35-55 >55 Subtotal All ages Total 10-34 35-55 >55 Recent Earl~ ha 0.76 0.51 0.61 1.87 4.32 5.04 1.18 10.55 8.60 4.71 1.76 15.08 0.70 1.15 0.09 1.93 14.38 11.41 3.64 29.43 % ha 6.4 1.73 0 0.08 1.81 35.9 5.23 2.21 0.74 8.18 51.2 6.71 2.35 0.78 9.84 6.6 0.23 0.18 0.17 0.58 48.8 38.8 12.4 13.90 4.74 1.77 20.41 % Change %!age ha class 8.9 0.97 -0.51 -0.53 -0.06 0.7 40.1 0.91 -2.83 -0.44 -2.37 -26.3 48.2 -1.89 -2.36 -0.98 -5.24 -58.2 2.9 -0.47 -0.97 0.08 -1.35 -14.9 -0.48 -6.67 -1.87 -9.02 -3.3 -58.5 -51.4 30.6 68.1 23.2 8.7 aThe time interval ranged from 25 to 40 years with a mean of 31.18 years. Thus, there is a pronounced trend toward fewer hectares of trees and those remaining are becoming more open. The size-age structure of the stands has not changed markedly over time except that large trees (>7.6 dm dbh) have declined dramatically. Trees in the intermediate age classes comprised between 85 and 90% of the total composition during both inventories (Table 7). Lindauer (1970) listed peachleaf willow (Salix amygdaloides) and Russian-olive as additional species within cottonwood communities along the Arkansas River. Cottonwoods averaged 64 trees/ha compared with 7.4 peachleaf willow and 12.4 Russian olive/ha. He noted the latter species was most prevelant in upstream samples. R. J. Niedrach reported observing tamarisk (salt cedar) near Lamar in 1913 and noted its subsequent expansion in 1921 and 1923 (Lindauer 1970). Lindauer's interviews with ranchers indicated floods in 1921 and 1937 promoted its �345 expansion. It has continued to move upstream and Bittenger and Stringham (1963) noted increased phreatophyte growth between Las Animas and La Junta between 1940 and 1961, to which they attributed diminished stream flows. Shrubs primarily tamarisk, were the most abundant vegetation type present during both sampling intervals and increased 21% over the 31.2 years (p < 0.10). Lindauer (1970) reported that tamarisk stands within the lower-stratum were older and the species was progressively spreading upstream. Their continued spread was evident during this study as greatest increases were noted in the middle stratum (Table 5). Colorado State Forest Service personnel could not distinguish tamarisk from other shrubs along the Arkansas using photo interpretation methods. However, .their 1985 sampling indicated that tamarisk dominated most sites containing shrubs and represented over 75% of the shrubs and small trees present. Sandbar willow (Salix interior) and coyote willow (S. exigua), not readily discernable as separate species, were the second most important shrubs with low densities of indigo bush amorpha (Amorpha fruticosa) and a few other species. Young Russian-olive may have been inventoried as shrubs. It is obvious that the quantity and quality of riparian habitats for wildlife along the lower Arkansas River have diminished rapidly in recent decades. The data point to 2 major causes: (1) dewatering and flood control, and (2) the invasion of tamarisk •. Either by itself would be devastating, but the 2 in combination provide little hope that highly struct~red wildlife habitats can be retained or economically restored. Lindauer (1970, 1983) documented the spread of tamarisk upstream along the Arkansas River since the early 1900's and noted its apparent capacity to raise the levels of soluable salts in the topsoil. As a consequence, only salt tolerant herbaceous species such as inland saltgrass (Distichlis stricta) and fireweed summer cypress (Kochia scoparia) grow in association with tamarisk. Diverse associations of food producing annuals were not present. Assuming tamarisk was not dominant along the Arkansas, it is probable there would be limited opportunity for cottonwoods and willows to become established. This is because several tributaries drain extensive areas of southeastern Colorado (Fig. 2) and infrequent heavy rains, like those in 1965, can still cause flooding. Flooding and high stream flows would probably not be sustained for long enough intervals to assure survival of new stands of seedlings. Pueblo Reservoir, John Martin Reservoir, and major irrigation diversions in combination make the potential of flooding from snowmelt a rarity. Flooding was not significant along the Arkansas in 1983 when major flooding was noted along other Colorado rivers. Flooding from snowmelt is usually sustained over longer intervals, a situation that is more conducive to cottonwood regeneration. Elimination of flooding and stabilization of reduced stream flows along the lower Arkansas has dramatically reduced opportunities for cottonwoods and willows to sustain themselves. Elimination of cottonwoods removes the upper portions of vertical structure essential to numerous passerines, raptors, fox squirrels (Sciurus niger), and other wildlife. Without trees, there is a reduction in both species richness and density or abundance. Elimination of �346 flooding results in plant growth on sandbars and mud flats and the elimination of edge, weed strips, and diversity essential to wildlife. As areas become established in continuous stands of perennial grasses, the weed-seed food base is eliminated which a majority of wildlife need to survive. This is especially critical in bottomland areas bordering semi-arid rangelands. Although tamarisk may provide nesting and protective cover for many wildlife species, densities will be severely restricted if a food base is lacking. An illustration of declining habitat quality on wildlife abundance is reflected by the apparent impact of John Martin Reservoir, and river dewatering, on downstream northern bobwhites (Colinus virginianus). Censuses of a downstream route in 1971~76 indicated on average of 1.0 calling males/station whereas above John Martin, the number of calling males/station during the same interval was 3.4 (Snyder 1978). The Arkansas still retains much more of a resemblance of a river in upstream areas. However, Pueblo Reservoir and its stream stabilizing impact will gradually degrade wildlife habitats downstream to John Martin Reservoir. The most recent aerial photos of the Arkansas River reviewed were taken in 1980. Field activities and observations from 1984 to 1987 indicated degradation of cottonwoods and the riverbottom continued, possibly at an accelerated rate. Cutting of old trees for firewood was frequently observed and has increased in recent years because of higher costs for natural gas, petroleum products, and electricity accompanied by a depressed farm economy. Loss of these large trees severely impacts several species of woodpeckers, fox squirrels, raptors, passerines, and other wildlife. Frequent fires in the bottomlands were apparent. In spring 1986, a large fire escaped in high winds to burn several kilometers of riverbottom west of Las' Animas killing hundreds of cottonwoods. Livestock grazing has long been a common use along the Arkansas and will continue into the future. South Platte River.--Reviews of historical records (Nadler 1978, Williams 1978, Crouch 1979, Smith 1980) indicate that cottonwoods were rare along the South Platte River on the plains of northeastern Colorado and western Nebraska during the 1800's. One grove of trees near the present town of Orchard was prominant and several lone trees in the Iliff-Proctor area were noted in early reports. Historically, the river was relatively straight, shallow, and broad with many small channels and islands. Mean widths from Greeley to Brush (Fig. 4) averaged over 400 m in 1867 (Nadler 1978) and Williams (1978) showed channel widths over 600 m in the Sedgwick-Julesburg vicinity. By 1952, Nadler noted that the mean width had decreased 86% to about 60 m. By 1977 the channel had widened to 90 m and observations following high water in 1983-84 indicated substantial width increases in downstream locations. Settlement of the valley, beginning in the 1860's brought ditch irrigation and diversion of river water. The senior adjudicated water right was dated 1859 (Nadler 1978). The Union Pacific railroad was completed in 1867 and stimulated establishment of numerous towns along the valley. By 1882 and elaborate network of canals had been completed along the valley and by 1885 residents were reportedly beginning to notice return flows to the river. In 1899, 287,226 ha were reportedly irrigated and irrigated land peaked at �WYOMING ---1---------- NEBRASKA I ------ .. _ ••• --~BURGI -------------- II lOr.. ' I I z m N CD :n » (/) A » ~~ ~A AIVt tI I NORTHEASTERN COLORADO I I I~ Z ('-1> i~ I(/) «'«'r w .p.. --.J Fig. 4. South Platte drainage in nortlleastern Colorado, inventoried portion (--), and strata (I). �348 500,372 ha in 1930 along with construction of numerous off-stream storage reservoirs (Smith 1980). Historians report that the South Platte became dry in late summer and fall prior to development of irrigation; the latter subsequently stimulated seepage and year-long flows. Intermittant flows may have been a factor in the lack of cottonwoods but it is more probable that browsing by buffalo (Bison bison) and periodic range fires were the primary deterrents to cottonwoods. Removal of buffalo, elimination of wildfires, and reduction of peak spring stream flows due to irrigation apparently allowed establishment of plains cottonwoods and peachleaf willows within areas that formerly were river channel. Major increases in numbers of plains cottonwoods apparently began after 1900 and the species peaked in density in the 1940's and 1950's (Sedgwick and Knopf 1987~). In more recent years, major diversion projects including the Colorado-Big Thompson (Adams tunnel - 1947) and 14 other diversions (Nadler 1978) brought water into the South Platte drainage to provide supplemental water for irrigation and urban development. Currently, Chatfield Reservoir, just south of Denver (Fig. 4), is the only major flood control storage reservoir on the South Platte after it leaves the mountains. The proposed Two Forks Reservoir, a few miles upstream from Chatfield Reservoir, may be constructed to provide additional water to the Denver metropolitan area in the near future. Other reservoirs occur along the South Platte in upstream mountainous areas and along a few of its tributaries. The South Platte drains about 59,910 km2 in central and northe?stern Colorado. The Narrows Reservoir, long proposed for construction on the South Platte a few miles west of Fort Horgan, has been only marginally funded and its future remains uncertain. If constructed it would potentially curtail high water and flood threats from the Cache la Poudre, Big Thompson, and Saint Vrain rivers and Crow Creek (Fig. 4). The intermittant Kiowa/Bijou Creek drainage would be the only major tributaries as Beaver Creek near Brush and Pawnee Creek near Sterling seldom flow significant water. A proposed diversion of South Platte excess flow, primarily winter flows, into the Frenchman Creek drainage is currently undergoing feasibility studies. Mean flow rates averaged among 83 years shows the rate of flow at Julesburg (Fig. 4) was 15.1 m3/s or 69% of the 21.8 m3/s rate upstream at Kersey. This reduction in flow was much less than that along the Arkansas River. However, considerable water is diverted from the South Platte and its tributaries before it gets to Kersey. Stream flows averaged among decades show no marked reduction from 1903 to the present with some increase in the last decade. Much of this flow retention has been attributed to seepage and return flows from irrigation and urban areas. An inventory of 5,445 ha of riverbottom within 36.4 km (17.7%) of 263.7 km was completed using stratified random sampling of linear mile (1.61 km) segments. Early year aerial photos were mostly from 1941 (a few from 1948-49) and recent photos were from 1979 (2 from 1978) yielding an average time span of 36.4 years. The 29 samples were distributed within 4 strata (Fig. 4). Hay meadow was the most abundant cover type (39.4%) along the South Platte during the early inventory (Table 8). However, it declined by 45% (p < 0.05). In contrast, grassland and cropland increased from early to recent intervals �349 (p < 0.05, Table 8). Developed land and standing water, representing small p;rcentages of the total, increased from early to recent inventories. River channel (river + unvegetated) also increased markedly (~<0.05) in contrast to dramatic declines along the Arkansas (Table 9). Grassland and river channel showed considerable variance among strata (p < 0.05) whereas most other vegetation types were fairly uniform among strata (Table 10). Table 8. Changes (ha/l.6l km) in vegetation types over a 36-year interval (1940's - late 1970's) along the South Platte River, northeastern Colorado. Vegetation Cottonwood Shrub Hay meadow Grassland Agriculture Developed River channel Standing water hall. 61 km Recent Earll 62.29 16.92 73.83 4.43 16.99 1.09 11.85 0.19 56.51 13.41 40.59 13.55 36.84 3.59 20.52 2.79 Change ha -5.78 -3.51 -33.24 9.12 19.85 2.50 8.67 2.60 % -9.3 -20.7 -45.0 205.9 116.8 229.4 73.2 1368.4 t 1.76* 1.67 5.33** 3.23** 3.87** 1.88* 5.45** 2.47** *p < 0.10 **p < 0.05 Hectares of shrub cover declined slightly (p > 0.10) along the South Platte. Ground inspections of the aerial photo classifications revealed some interpretive overlap between shrub and hay meadow classifications. However, both types declined from early to recent intervals (Table 8). Primary shrub species along the South Platte River include sandbar and coyote willow, a few diamond willow (Salix lutea), and large patches of western snowberry (Symphorocarpos occidentalis). Indigo bush, woods rose (Rosa woodsii), poison ivy (Toxicodendron radicans), and currant (Ribes aureum) were present in lower densities. Only a few scattered Tamarisk occur along the South Platte. Stands of plains cottonwoods containing peachleaf willow and occasionally a few other tree species occupied 33% of the inventoried bottomland during the early interval and 30% during the recent interval at which time they were the dominant cover (Table 8). The decline of 9.3% (p = 0.046) was not distributed among all strata as the 2nd from upper stratum showed an increase in area occupied over time whereas the 1st and 3rd strata showed considerable decline (P < 0.005, Table 10). However, hectares of cottonwoods were comparable among all strata (Table 6). Young trees «1.5 dm-dbh) showed an early to recent decline of 33.6% (p = 0.087) in occupied area but initially comprised only 10% of the composition (Table 11). Trees in the 1.5-3.8 and 4.1-7.6 dm age classes in combination comprised 88 to 90% of the composition during both inventories and showed more modest declines in occupied area (Table 11, Fig. 5). Large trees (>7.6 dm) occupied only 2-3% of the area and may have increased slightly (P > 0.10). �w V1 o Table 9. Early to recent changes/sample (ha/l.6 km) of vegetation types or land use occurring along Colorado's low-elevation riparian zones.a Vegetation/use Cottonwood stands Shrubs Hay meadow Grassland Agriculture/development River channel Arkansas Early Recent 29.4 39.1 34.2 25.0 3.2 25.1 20.4 47.3 29.4 22.5 22.7 12.6 River South Platte Early Recent 62.3 16.9 73.8 4.4 18.1 11.9 as tanding water and other minor covers were excluded. 56.6 13.4 40.6 13.5 40.4 20.5 Colorado Early Recent 18.0 15.3 23.6 5.0 9.8 15.0 14.9 16.3 18.0 . 6.5 13.3 14.2 Rio Grande Early Recent 28.0 10.6 110.4 1.4 1.3 9.9 30.6 8.0 87.7 5.0 23.4 6.2 �351 Table 10. Average change of vegetation types (ha/l.61 km) among strata from early to recent intervals along the South Platte River, northeastern Colorado. Stratum Vegetation 1 2 3 4 F value Cottonwood Shrub Hay meadow Grassland Agriculture Developed River channel Standing water -13.1 +0.5 -29.0 +11.0 +12.6 +3.5 +12.9 +3.3 +9.7 -6.9 -38.9 +9.7 +15.4 +4.9 +0.3 +5.3 -13.2 -2.6 -34.1 +1.9 +37.9 +0.1 +8.5 +0.8 +0.2 -8.6 -31.1 +20.3 +3.2 +1.5 +14.2 +0.4 3.92* 0.84 0.11 3.36 1.09 0.57 5.01* 0.85 *p < 0.05 Table 11. Changes (ha/l.61 km) by age class and canopy cover of cottonwood stands over a 36-year interval (1940's to late 1970's along the South Platte River, northeastern Colorado. Age-class (dm-dbh) <1.5 Canopy cover (%) 10-34 35-55 >55 Subtotal 1.5-3.8 10-34 35-55 >55 Subtotal 4.1-7.6 10-34 35-55 >55 Subtotal >7.6 10-34 35-55 >55 Subtotal All ages Total 10-34 35-55 > 55 Earl:t:Interval % ha 2.60 1. 74 1.89 6.23 13.79 8.45 3.93 26.17 17.28 6.02 5.26 28.56 0.67 0.27 0.38 1.32 34.34 16.48 11.46 62.28 Recent Interval % ha 10.0 2.15 1.23 0.76 4.14 42.0 10.17 8.34 4.52 23.03 45.9 15.05 9.12 3.47 27.64 2.1 1.04 0.41 0.24 1.69 55.1 26.5 18.4 28.41 19.10 8.99 56.50 Change %!age ha class 7.3 -0.45 -0.51 -1.13 -2.09 -33.6 40.8 -3.62 -0.11 +0.59 -3.14 -12.0 48.9 -2.23 +3.10 -1. 79 -0.92 -3.2 3.0 +0.37 +0.14 -0.14 +0.37 +28.2 -5.93 +2.62 -2.47 -5.78 -17.3 +15.9 -21.6 -9.3 50.3 33.8 15.9 �352 AGE CLASS (DM -DBHI 35- c1.5 30 25 ~ 1.5-3.8 0 4.1-7.6 ~ .7.6 ~ .•.. U) .•... ';a J: 20 15 - Z « w ~ 10 5 o EARLY RECENT EARLY REceIT EARLY. REcafT 10-34 35-55 >55 CANOPY COVER Fig. 5. Early to recent changes/ sample (E ha/1. 61 km) by s i ze+age clas~es (dm-dbh) and canopy cover (%) of cottonwood stands along the lower South Platte River, northeastern Colorado. �353 Open stands (10-34% canopy cover) of cottonwoods that initially comprised 55% of the total declined 17% (P = 0.02), whereas those of intermediate (35-55%) density increased by 16% (P-= 0.016) to occupy 34% of the area (Table 11, Fig. 5). Trees in dense stands-(>55%) initially comprised 18% of the area occupied by trees but declined 22% (~ = 0.42, Fig. 5). Based on these data there was a modest overall decline in cottonwoods along the South Platte but the decline was not distributed uniformly among strata (Table 10). However, stands of trees continued to be the dominant cover type within the inventoried bottomlands and averaged over 56 ha/l.6l km. The proportion of young replacement trees declined during the 36-year interval providing evidence of insufficient natural reproduction and survival needed to sustain former densities. Few large trees were present during either inventory. Open stands dominated during both inventories but there was no pronounced trend toward opening of stands. Within open stands of trees along the South Platte River, Lindauer (1983) found that peachleaf willow comprised 40% of the 95 trees/ha density. In closed stands, peachleaf willow comprised 25% of the composition which averaged 120 trees/ha. Data from Christy (1973) indicated cottonwoods averaged about 85 trees/ha and other minor species, green ash, American elm (Ulmus americana), and boxelder (Acer negundo) averaged about 7-8 trees/ha within sites classified as cottonwood communities. Thus, cottonwoods comprised over 90% of the tree composition. In comparison within mixed communities, plains cottonwoods averaged 78% and peachleaf willow represented 22% of the composition with respective densities of'about 85 and 24 trees/ha or a combined tree density of 109/ha. Sedgwick and Knopf (1986) recorded much iower cottonwood densities averaging 23.9 trees/ha during their recent studies on the South Platte Wildlife Management Area. Crouch (1979) reported 94.6 and 117.9 trees/ha respectively on grazed and ungrazed study areas in the same vicinity in 1961. By 1978 densities had declined to 43.5 and 79.1 trees/ha yielding declines of 53% on the grazed site and 33% on the ungrazed site during the l7-year interval. This rate of decline was dramatically greater than recorded over the 36-year extensive photo interpretive evaluation. Sedgwick and Knopf (1987b) considered the cottonwoods within their study to be in a decadent age class representative of declining tree stands. They noted that 43% of the trees were 35-55 years old. The South Platte riverbottom with respect to status and trends of cottonwoods and wildlife is in relatively good condition when contrasted with that of the Arkansas River. Cottonwoods occupy between 2 and 3 times greater area/l.6l km along the South Platte (Table 9) and its 0.75 to 1.0-km wide flood plain is markedly wider than that of the Arkansas or any other Colorado River. Opportunity for occasional to frequent flooding still occurs along the lower South Platte and tamarisk, although present in small numbers, does not appear to be a major threat. Observations following the severe winter of 1983-84 indicated extreme cold weather may be a major deterent to tamarisk in northeastern Colorado. Extensive winter kill of top growth was noted along both the Arkansas and South Platte. Although root sprouting and regrowth has been observed, tamarisk along the South Platte remains in poor vigor. Sedgwick and Knopf (1987b) reported that the last phase·of significant overstory development in-their South Platte study area occurred between 1929 �354 and 1949. After that cottonwood reproduction fell below levels necessary to sustain an equilibrium population. Data from Crouch (1978) and the extensive inventory provide additional evidence of decline although the latter data indicate the decline has been moderate (O.3%/year) rather than rapid. A few young trees were established following 1965 and 1973 floods but regeneration was not enough to offset reductions in stands of trees, their aging or the progression toward reduced canopy cover. Flooding and sustained high stream flows in 1983-84 markedly stimulated natural reproduction of cottonwoods, other trees, shrubs, and grape vines. Cottonwood establishment was widely distributed and subsequent survival through 1987 was relatively good providing hope that stands of cottonwoods along the lower South Platte received a substantial boost in the form of replacement trees. It is doubtful that these new seedlings will reverse long-term declines of cottonwoods along the South Platte but should slow the rate of decline. In some locations, e.g.,·the Dodd Bridge Wildlife Area, the river channel seems to have deepened too much in relation to the adjacent flood plain and little natural regeneration has occurred. In other locations, spring to early fall livestock grazing has eliminated all seedlings from both recent and previous decades so that cottonwood stands are decadent and deteriorating along with their understory shrubs. Data from Crouch (1978) indicates stands of cottonwoods deteriorated more rapidly within a grazed site than within an ungrazed site along the South Platte. Historically, the South Platte River was several times wider and straighter than it is today and was nearly treeless (Nadler 1978, Williams 1978). Devel.opment;of extensive LrrLgat.Lon along the Front Range and downstream apparently reduced peak stream flows and altered flows so that the river flowed yearlong. As a consequence, willows and cottonwoods invaded former river channel, possibly during drought years (Nadler 1978), so that the river channel was further restricted. Sites containing willows, cottonwoods, and herbaceous vegetation became collectors of sediments during subsequent floods so that these sites, over time gradually became more elevated from repeated flood deposits (Nadler 1978, u.S. Dep. Inter. 1981). Continued elevation increases first made these sites too mesic for willows to establish, and as elevations continued to increase they became too high for cottonwoods to become established upon. Some of these sites still contain gradually opening stands of mature to overmature cottonwoods, whereas other locations have given way to areas dominated by perennial grasses. This process along the South Platte in northeastern Colorado appears to be slow because the river still retains numerous usually dry side channels, and occasional floods, as in 1983-84, scour new locations and create new sites suitable for willow and cottonwood germination. Cottonwoods establish in narrow linear bands as evident from inspection of aerial photos. Although some regeneration of willows and cottonwoods continues, Sedgwick and Knopf (1988) suggest it is probably not at a rate sufficient to sustain these species over time. As the flood plain became too elevated to sustain cottonwood regeneration along the Platte River in Nebraska, other more shade tolerant mesic trees invade (U.S. Dep. Inter. 1981). These include eastern red cedar (Juniperus virginiana), box elder, mulberry (Morus spp.), and green ash. Sedgwick and Knopf (1988) presented data supporting the hypothesis that green ash would be the most probable mesophytic tree to achieve overstory dominance following decline of cottonwoods along the So'ut h Platte. As documented in this study, green ash shows evidence of rapid expansion apparently promoted in flooding �355 in 1983-84. Russian-olive also has shown evidence of limited invasion. However, flooding in 1983 killed some seedlings and it is anticipated natural expansion will primarily occur along flood plain edges and adjacent meadows. Green ash appears tolerant of poor soils which have high alkalinity and soluable salts and are low in nutrients, it is shade tolerant invading under overstory cottonwoods, it is not readily killed by flooding, and it is not highly succeptable to livestock browsing. Green ash along the South Platte are relatively young trees and few if any old trees exist within the flood plain. Personnel of the CDOW and DSFS have and are continuing to attempt to establish other tree species including oak (Quercus spp.), and walnuts (Juglans spp.) with no success to date. Poor soil conditions are believed a major hinderance to survival of these species. Colorado River.--The Colorado River and its numerous tributaries drain an area of about 46,196 km2 of primarily mountainous terrain. Tributaries including the San Juan, Delores, White, and Yampa, which join the Colorado River further downstream, also drain extensive areas of Western Colorado. The Colorado River and its tributaries are confined within mountain valleys through most of their passage in Colorado and frequently are subjected to steep gradients. Narrow valleys severely limit the extent of riparian habitat along the streams. Not until the Colorado River joins with the Gunnison River at Grand Junction does it enter into a relatively broad valley and with reduced stream gradient. Like the rivers in Eastern Colorado, the Colorado River valley was the the major focal point of early travel and settlement. Thus, the narrow riparian zone along the stream was severely impacted by railroads, highways, and settlements which crowded the riverbanks in many locations. In intermediate to higher elevations livestock grazing, mining, and lumbering were early developments impacting the river and its tributaries. Numerous small diversions, flood-irrigated hay meadows, and livestock have impacted bottom lands along the narrow valleys, through the decades. At lower elevations fruit orchards, alfalfa, and other crops are grown but opportunities for irrigation are much less in Western Colorado than in the eastern part of the state. Therefore, river flows, which were much greater than those for East Slope rivers, were not severely reduced by early settlement and development of local irrigation. Alteration and reduction of stream flows and water quality along the Colorado have primarily occurred within the last 50 years with the development of high mountain water diversions to the East Slope and the construction of numerous reservoirs to retain snowmelt for delayed release during peak irrigation downstream. However, most of the water entering the Colorado drainage exits the state to be impounded and used for urban areas and irrigation in the arid Southwest. Narrowleaf cottonwood (Populus angustifolia) is the dominant species along the Colorado River and its tributaries (Fig. 1), generally occurring between 1,524 and 2,438 m elevation. A less abundant species, lanceleaf cottonwood (P. acuminata), occurs within a slightly broader elevational range (Harrington 1954). The Rio Grande cottonwood (P. wis1izeni), the same as the plains cottonwood in general appearance, is confined to lower elevations in western Colorado. �356 Just when tamarisk was introduced to the lower Colorado River valley is unknown but it has spread extensively within the lower Colorado and Gunnison valleys. Russian-olive is also abundant in many locations along these West Slope rivers at lower elevations. No pre-settlement data were found in the literature but it is assumed that cottonwoods and willows were present all along the Colorado River probably to a greater extent than they are today. Photos taken within the Grand Valley in 1882-1904 show scattered cottonwoods along the Colorado. Flooding along the Colorado River is primarily a consequence of snow melt and above normal spring temperatures. Major reservoirs on the Gunnison River have severely restricted peak flows in recent years. Major peak flows or flooding were recorded frequently in the early 1900's along the Colorado River (1909, 1912, 1914, 1917, 1918, 1921, 1928, 1935, and 1938). Peak flows in more recent decades were recorded in 1957, 1983, and 1984. The Colorado River was sampled along 167.3 km from Glenwood Springs to the Utah-Colorado Border (Fig. 6). Within that distance it dropped about 457 m in elevation from 1,829 to 1,372 m. In recent years stream flows at the upper part of the sampled area averaged 3-4 times those of other inventoried rivers and, because of its confluence with the Gunnison River at Grand Junction, it left the state with a flow approximately 75% greater than at the upper end of the sampled area (Tables 2, 3). Inventory of 1,826 ha of riverbottom within 33.8 km (20.2% sample) was accomplished within 4 strata (Fig. 6). Original year aerial photos were from 1951-57 and recent photos were from 1978-80 yielding an average time- span of 25.1 years, considerably less than that along other sampled rivers. Hay meadow, the most abundant vegetation classified, declined by 23.7% (p < 0.10) during the sampled interval (Table 12) with the primary decrease occurring in the lower 4th stratum (Table 13). Grassland represented only 5.7% of the sampled area during early sampling but increased 31% in all but the 2nd stratum. Agriculture or cropland represented about 10% of the sampled area and changed little over the 25 years. The amount of developed land and standing water were insignificant in early year samples but increased to represent 10% of the area during the recent inventory (Table 12). Overall, the river channel changed little but variance among strata was evident with channel widening in the 2 upstream strata but apparently narrowing downstream (Table 13). Shrubs occupied about 17-18% of the sampled riverbotton and showed evidence of increasing slightly, primarily in the 2nd stratum. Only about 3-4 ha/l.6l km of shrubs were present/sample within the upper stratum. However, shrubs occupied over 20 ha/l.6l km within the 2nd and 3rd strata and about 15 ha/l.6l km within the lower stratum. Tamarisk was the dominant shrub, especially at lower elevations where dense stands similar to those along the Arkansas River were common. Field inspection revealed that Russian-olive was common in some locations and may be increasing. Willows were common especially within the upper 3 strata. �,------------- I ---------------- NORTHWESTERN -- WYOMING ---- _-- - ----- _----- _---- COLORADO N ~.t.- <;, I -c I::J V-l VI -.j Colorado River drainage in Western Colorado with i~entoried Fig. 6. portion (--I and strata (II. �358 Table 12. Changes (ha/l.6l km) in vegetation types over a 25-year interval along the Colorado River, western Colorado (1955-80). Vegetation Cottonwood Shrub Hay meadow Grassland Juniper Agriculture Developed River channel Standing water ha/l. 61 km Early Recent 17.98 15.28 23.58 4.99 0.14 8.78 1.06 14.93 0.21 Change % t -17.5 +6.5 -23.7 +30.9 -35.7 -7.4 +388.7 -5.2 +1661. 9 1.74* 0.93 1.94* 0.71 ha 14.84 16.28 18.00 6.53 0.09 8.13 5.18 14.15 3.70 -3.14 +1.00 -5.58 +1.54 -0.05 -0.65 +4.12 -0.78 +3.49 0.55 3.38** 0.87 3.00** *p < 0.10. **P<0.05. Table 13. Average change of vegetation types (ha/l.6l km) among strata from early to recent intervals (1950's-1980) along the Colorado River, western Colorado. Stratum Vegetation Cottonwood Shrub Hay meadow Grassland Agriculture Developed River channel Standing water 1 -3.4 -0.9 -6.0 +3.8 0 +4.9 +1.2 -0.1 2 -7.0 +3.1 -3.1 -7.2 -0.3 +5.0 +3.0 +0.9 3 -0.7 +0.2 +2.4 +3.1 -0.9 +0.5 -3.6 0 4 F value -1.9 +1.1 -14.8 +5.1 -1.1 +5.5 -2.7 +8.6 0.52 0.48 2.72 1.90 0 0.93 4.73* 5.75* *p < 0.05. Stands of cottonwoods occupied about 21% of the sampled Colorado River bottomlands during the early inventory and about 17.5% during the recent sampling (Table 12). The average rate of decline was 3.04 ha/l.6l km (p = 0.08). Within the upper stratum, extending about 30 km downstream fromGlenwood Springs (Fig. 6), stands of trees were especially sparse averaging only 3.6 ha/l.6l km during the early inventory. However, they declined over 90% to average only 0.26 km/l.6l km during the recent sample (p = 0.02). The greatest decline/sample unit was 7 ha within the 2nd stratum. -However, trees occupied 38.6 and 31.6 ha/l.6l km respectively in early and recent �359 inventories. Hectares/sample unit were much higher than within other downstream strata where cottonwoods averaged about 12-15 ha/l.6l km and declined at more modest rates. The age structure of cottonwoods along the Colorado appeared to be that of a healthy stand with 58% of the trees occupying the 2 younger age classes with a fair proportion of large trees (Table 14, Fig. 7). The percentage of young trees «1.5 dm-dbh) declined almost 50% during the 25-year interval but still remained nearly twice that within East Slope samples. Numbers of large old trees (>7.6 dm) also declined dramatically. Table 14. Changes by age-class and canopy cover (ha/l.6l km) of cottonwood stands over a 25-year interval (1950's to 1980) along the Colorado River, western Colorado. Age-class (dm-dbh) <1.5 Canopy cover CO 10-34 35-55 >55 Subtotal 1.5-3.8 10-34 35-55 >55 Subtotal 4.1-7.6 10-34 35-55 >55 Subtotal >7.6 10-34 35-55 >55 Subtotal All ages Total 10-34 35-55 >55 Recent Earll ha 1.89 1.34 1.49 4.72 2.10 1.94 1. 71 5.75 2.78 1.86 1.67 6.31 0.06 0.57 0.58 1.21 6.83 5.71 5.45 17.99 % ha 26.3 1.26 0.54 0.63 2.43 32.0 3.32 1.65 1.36 6.33 35.0 2.95 1.00 1.93 5.88 6.7 0.07 0.09 0.04 0.20 38.0 31. 7 30.3 7.60 3.28 3.96 14.84 % Change %!age ha class 16.4 -0.63 -0.80 -0.86 -2.29 -48.5 42.7 +1.22 -0.29 -0.35 +0.58 +10.1 39.6 +0.17 -0.86 +0.26 -0.43 -6.8 1.3 +0.01 -0.48 -0.54 -1.01 -83.4 +0.77 -2.43 -1.49 -3.15 -17.5 51.2 22.1 26.7 Changes in stand densities were more discouraging than changes in age structure. Within the early inventory samples, stands were well distributed among all canopy cover classes. However, by the recent interval open stands had increased 11% whereas intermediate stands (35-55% canopy cover) had declined 42% and dense stands had decreased 27%. Thus, the same general pattern as observed on the Arkansas and South Platte rivers was evident. �360 AGE CLASS (OM -OBH] 8 tsSJ >7.6 7 E ~ ••••• to ••••• <, m ~ 4.1-7.6 ~ 1.5-3.8 <1.5 6 5 4 ..c: Z 3 :E 2 « .. w 1 0 EARLY RECENT 10-34 EARLY RECENT 35-55 EARLY RECENT >55 CANOPY COVER Fig. 7'. Early to recent changes/sample (25: ha/l.6l km) by size-age class (dm-dbh) and canopy cover (%) of cottonwood stands along the lower Colorado River, western Colorado. �361 Extensive flooding occurred along the Colorado River in 1983-84 and extreme stream flows were recorded. Scouring of previously deposited sediments was noted in some locations widening the river channel and promoting a rocky streambed. However, natural regeneration of cottonwoods was noted in numerous locations along the river. Subsequent observations indicated loss of numerous trees to beaver (Castor canadensis). Since the riparian zone is narrow in many locations, the problem of loss to beaver is enhanced. Wildlife use of the riverbottom is severaly restricted in most areas by the relative narrow valley and restricted quantity and quality of phreatophytes. A heavily traveled interstate highway and railroad crowd the riverbank in many locations and numerous developments have been completed in recent decades. Rio Grande River.--The Rio Grande River drains approximately 19,194 km2 of which 7,612 km2 lies within a closed basin. River water is nearly exclusively from snow melt primarily from the San Juan Range with lesser amounts from the Sangre de Cristo Range to the east. The river enters into the western part of the S~n Luis Valley, a high elevation (2,286-2,438 m) relatively flat plateau and travels through a farming area for approximately 100 km before entering a canyon and exiting into New Mexico (Fig. 8). Drainages in the northern part of the San Luis Valley do not extend to the Rio Grande but enter the ground to subirrigate parts of the valley. Subirrigation, irrigation water from the Rio Grande and its tributaries, and artesian wells prompted rapid settlement and development of irrigation in this high, cold desert basin. Spanish immigrants explored and attempted to settle the area in prior centuries but their first permanent settlement of San Luis was established in 1851 - the earliest known settlement in Colorado. The first recorded water rights date from 1852 known as the San Luis People's Ditch at San Luis on Culebra Creek (Athearn 1985). Several more Spanish settlements which used irrigation water for farming developed along the Rio Grande and its tributaries in subsequent years. Several large diversion canals were constricted between 1880 and 1890 and 99% of the irrigation canals in the valley had been constructed by 1890 (Tipton 1939). Without reservoir storage to regulate water flow, farmers attempted to increase storage of water in the ground resulting in creation of numerous seeps and alkaline flats and the loss of farmground. LaJara Reservoir construction began in 1910 and by 1938, 235,000 ac. ft. of reservoir storage existed within the upper Rio Grande Drainage (E. Dumpf, Pers. Commun.). Additional major regulation of stream flow from high mountain reservoirs was initiated in 1949 and later when the San Luis Valley Project was implemented by the u.S. Bureau of Reclamation. More recently, development of center pivot irrigation has prompted rapid conversion to sprinkler irrigation from wells causing major declines in groundwater levels. However, due to 3 years of above normal stream flows, groundwater levels along the Rio Grande are above 1977 levels (E. Dumpf, Pers. Commun.). Rio Grande stream flows based on 10-year averages since 1890 have not shown major evidence of declining in recent decades at Del Norte in the west-central portion of the San Luis Valley (Fig. 8). There, mean daily flows have averaged about 25.3 m3/s. Partial regulation of flows following construction of upstream reservoirs in recent decades has undoubtedly altered flow patterns with increased volumes into late summer for irrigation. �w oN SAN LUIS VALLEY, DEL COLORADO NORTE N ---- -- -- ---- ------ -- -- -- -- -- ------ -- --- -- ----- ----NEW MEXICO Fig. 8. e I) . Rio Grande River drainaBe in southern Colorado witll inventoried portion (--) and strata �363 Further downstream at Alamosa, mea~ daily flows average only about 30% of those at Del Norte. Mean flow rates averaged over 11.2 m3/s between 1913 and 1930 at Alamosa, but declined to less than one-half that volume since 1930. Flooding or excessive flows along the Rio Grande were evident in 1907, 1911, 1917, 1921, 1927, 1941, 1977, 1979, 1981, and 1983 to 1987. Information concerning status of cottonwoods along the River in the 1800's and early 1900's could not be found. The Rio Grande River was sampled along 177.4 km from South Fork downstream to below Alamosa (Fig. 8). Sampling intensity averaged 27.4% including 20 1.6l-km units distributed among 3 strata containing 3,263 ha of riverbottom. Initial aerial photos were mostly from 1941 (1 from 1944) and recent photo data ranged from 1973 to 1983 yielding an average time span of 36.8 years. Hay meadow-dominated vegetation types (Table 15) and comprised 68 and 54% of the sampled area respectively during early and recent samples. The decline of 20.6% (p <0.05) occurred primarily within the 2 upper strata (Table 16). Grassland was a minor vegetation type initially ~ut increased substantially (P <0.10), primarily within the 2 upper strata. During the early sampling interval only 2 of 20 samples contained cropland but this number increased to 9 of 20 within the recent inventory and the percentage changed from 0.1 to 13.4% (p < 0.05). Developed l?nd and standing water were minor components in both sample intervals. River channel showed a 36.7% decrease in occupied area (p < 0.05) that was distributed among all strata (Table 15). Shrub cover declined by 25% from early to recent intervals (p < 0.10). Willows were the primary shrub component within the riverbottom and comprised only a minor percentage of the inventoried area during both sampling periods (Table 15). Table 15. Changes (ha/l.6l km) in vegetation types over a 36.8 year interval (1941 to 1973-83) along the Rio Grande River, San Luis Valley, Colorado. hall. 61 km Vegetation Cottonwood Shrub Hay meadow Grassland Agriculture Developed River channel Standing water *p < 0.10. **P < 0.05. Change Early Recent ha % t 27.99 10.54 110.43 1.40 0.18 1.12 9.91 1.63 30.56 7.93 87.68 5.00 21.75 1.63 6.27 1.87 +2.57 -2.61 -22.75 +3.60 +21.57 +0.51 -3.64 +0.24 9.2 24.8 20.6 257.1 1.46 2.31* 2.79** 2.42* 3.05** 1.43 6.86** 0.56 'V 45.5 36.7 14.7 �364 Table 16. Average change of vegetation types (ha/l.6l km) among strata from early to recent intervals along the Rio Grande River, San Luis Valley, Colorado. Vegetation 1 Stratum 2 4 F value Cottonwood Shrub Hay meadow Grassland Agriculture Developed River channel Standing water +5.9 -2.8 -44.4 +12.6 +30.6 -0.3 -2.1 +0.5 +3.6 -4.1 -30.4 +1.2 +32.5 +1.6 -5.3 +0.9 -1.0 -0.8 +1.4 0 +2.7 -0.2 -2.9 -0.7 0.85 0.53 3.18 2.89 3.31 2.92 4.48* 1.22 *P<0.05. Cottonwoods were moderately abundant within the upper stratum of the Rio Grande increasing from 23.7 to 29.6 ha/l.6l km (Table 6) a~d were more common within the middle stratum where they increased from 48.1 to 51.8 ha/l.61 km. However, within the lower stratum in areas downstream from Alamosa they were completely absent along several sample units. The average occurrence in the lower stratum was only 8.0 and 6.9 ha/l.61 km respectively from early to recent inventories (Table 6). The overall increase was modest, 9.2% (P = 0.12). Initially cottonwoods occupied 17.1% of the sampled area and this percentage increased to 18.8% by the 2nd interval. Young trees «1.5 dm) comprised 10.4% of the composition during both sampling intervals and increased 9.3% in occupied area (Table 17). Trees of intermediate size (1.5-3.8 dm) declined over the interval (P = 0.13) glvlng way to the next larger (4.1-7.6 dm) age class that increased 27.2% (p = 0.16) (Fig. 9). This latter group dominated among age classes during both-intervals (Table 17). Older trees (>7.6 dm) represented only about 3% of the total composition during both intervals but showed limited evidence of increasing in occupied area (p = 0.56). Open stands (10-34% canopy cover) initially occupied only 31% of the timbered area and declined to 25% by the 2nd inventory (P = 0.25). In contrast, stands of intermediate density increased from 33 to 40% occurrence (31%, P = 0.015). Dense stands increased more modestly (9%, P = 0.49) representing 35% of the total composition during both sampling intervals. Based on all 3 variables, area occupied, age structure, and stand density, cottonwoods along the Rio Grande River were by far the most healthy among the 4 inventoried rivers. However, Colorado Division of Wildlife personnel in the San Luis Valley report almost no recent reproduction of narrowleaf cottonwoods along the Rio Grande or along its tributaries (Alamosa, La Jara, and Conejos rivers) in the 1980's (E. Dumpf, pers. commun.). Floods along the Rio Grande in recent years have been short term and apparently not adequate to sustain survival of seedlings. Beaver were also reported to be causing considerable loss of cottonwoods within the Rio Grande drainage. �365 Changes (ha/l.6l km) of cottonwood stands by age class and canopy Table 17. cover over a 36.8-year interval (1941 to 1973-83) along the Rio Grande River, San Luis Valley, Colorado. Age-class (dm-dbh) <1.5 Canopy cover (%) 10-34 35-55 >55 Subtotal 1.5-3.8 10-34 35-55 >55 Subtotal 4.1-7.6 10-34 35-55 >55 Subtotal > 7.6 10-34 35-55 >55 Subtotal All ages Total 10-34 35-55 > 55 Early ha 1.16 0.71 1.04 2.91 3.53 3.67 2.50 9.70 3.93 4.83 5.81 14.57 0.17 0.15 0.50 0.82 8.79 9.36 9.85 28.00 Recent % ha 10.4 1.79 0.86 0.53 3.18 34.7 3.54 2.54 1.83 7.91 52.0 2.16 8.62 7.76 18.54 2.9 0.11 0.21 0.64 0.96 31.4 33.4 35.2 7.60 12.23 10.76 30.59 % Change %/age ha class 10.4 +0.63 +0.15 -0.51 +0.27 25.8 +0.01 -1.13 -0.67 -1. 79· -18.5 60.7 -1.77 +3.79 +1.95 +3.97 +27.3 3.1 -0.06 +0.06 +0.14 +0.14 +17.1 -1.19 +2.87 +0.91 +2.59 -14 +31 +9 +9.3 24.8 40.0 35.2 +9.3 Narrowleaf cottonwoods were by far the dominant species present although a few other species may occur. No Russian-olive were noted during 1985 inspections but the species may be present in certain locations. Narrowleaf cottonwoods were the primary trees planted at rural and urban residences in the San Luis Valley indicating the species was well adapted to the climate if supplemental water was available. South Fork of the Republican River.--The South Fork of the Republican River is a relatively small stream that drains about 4,725 km2 of east-central Colorado extending approximately 115 km west from Kansas (Fig. 10). It flows water for about 48 km through northern Kit Carson and southern Yuma counties before passing into Kansas and Nebraska where it joins with the Arikaree, North Fork of the Republican, and Frenchman Creek. Above where it flows in Colorado, a few intermittant seeps and springs can be found. A small recreation reservoir which fluctuates depending on intermittant flows from upstream rains, is on the Republican near Flagler and is managed by the Colorado Division of Wildlife. �366 AGE CLASS 10M -OBHI 12 lS.:Sl >7.6 rza 4.1-7.6 11 ~ 13' 10 9 ~ . to 1.5-3.8 <1.5 8 7 6 5 4 3 2 1 o EARLY RECENT EARLY RECENT 10-34 35-55 EARLY RECENT >55 ' CANOPY COVER Fig. 9. Early to recent changes/sample (~ ha/l.6l km) by size-age class (dm-dbh) and canopy cover (%) of cottonwood stands along the lower Rio Grande River, San Luis Valley, southern Colorado. �367 z m CD :::0 » (J') " » EAST-CENTRAL COLORADO N o IDALIA BONNY ". » z (J') » (J') o Fig. 10. Reservoir BURLINGTON Republican River drainage in eastern Colorado showing and the inventoried 'portion (--) of the South Fork. Bonny �368 Bonny Dam was constructed by the U.S. Department of Interior, Bureau of Reclamation in the late 1940's and early 1950's on the South Republican about 10 km west of Kansas (Fig. 10). The reservoir backs water about 5 km and is used primarily for flood control and recreation. Only limited irrigation is permitted. Therefore, water levels within the reservoir are stable except during infrequent floods. Downstream flows have been regulated by Bonny Reservoir since July 1950. The average discharge over 34 years (1952-85) was 0.55 m3/s near Hale below Bonny Reservoir. The maximum flow was 4.03 m3/s in a sample of 14 recent years (1965-84). In contrast, 2 major floods occurred prior to construction of Bonny Reservoir. In 1935 the greatest flood known occurred with a maximum discharge of 2,884 m3/s at a site a few km above Hale. A discharge of 106.1 m3/s was recorded in May 1947 while the dam was under construction. A continuous small flow is released from Bonny Reservoir whereas in previous years the stream often became dry in late summer and fall. The Colorado Division of Wildlife (CDOW) owns or leases most of the bottomland from Bonny Reservoir downstream to Kansas. Management of CDOW properties has not been intensive and spring-summer livestock grazing was permitted under a 25-year contract that terminated in 1987 on the property containing the Hale Ponds. Most private lands along the stream have been intensively grazed in recent years. Personnel of the Colorado State Forest Service were requested to inventory approximately 4.8 km of riparian habitat west from Kansas. Early photos were from 1961 while recent photos were from 1975. Subsequent contact with the East-Yuma County, U.S. Department of Agriculture Soil Conservation Service District office located aerial photos from 1938. Therefore, changes from 1938 to 1961 and 1975 were examined (Tables 18, 19). These data represent a specific area of the South Republican a few km below Bonny Reservoir and do not represent a random sample of the stream. Table 18. Changes (~ ha/l.6l km) of vegetation types among intervals from 1938, 1961, and 1975 in the Hale Ponds vicinity, South Republican River, Colorado. .Vegetation 1938 1961 1975 Cottonwood Shrub Hay meadow Grassland Agriculture Developed River channel 6.6 45.8 8.5 68.9 20.4 0.3 25.0 42.8 7.3 0.3 96.2 20.1 0 8.8 62.8 12.4 2.3 56~0 37.7 0 4.3 Grassland was the dominant vegetation type in 1938 and 1961 but decreased in the 1975 sample (Table 18). Hay meadow has been minor in occurrence and cropland has recently increased. Inspection of aerial photos clearly revealed �Table 19. Changes (ha/1.61 km) by age class and canopy cover within cottonwood stands in the vicinity of Hale Ponds, South Fork of the Republican River, Colorado among 1938, 1961, and 1975 sample intervals. Age class (dm-dbh) <1.5 Canopy cover (%) 10-34 35-55 >55 Subtotal 1.5-3.8 10-34 35-55 >55 Subtotal 4.1-7.6 10-34 35-55 >55 Subtotal >7.6 10-34 35-55 >55 Subtotal All ages Total 10-34 35-55 >55 1938 ha 1961 % ha 1975 % ha 5.8 0 0 0 0 1938-61 1961-75 1938-75 0 +0.65 -2.49 -1.84 33.7 14.07 7.16 0.69 21.92 34.9 +12.15 +7.51 +19.66 58.5 8.19 13.67 15.48 37.34 59.4 +23.86 +12.28 +36.14 5.7 -0.45 +2.73 +2.28 35.4 37.5 27.1 +13.19 +15.02 +8.00 +4.15 +8.01 +7.87 +17.34 +23.03 +15.87 27.9 1.88 0.62 0 2.49 34.2 7.41 5.80 1.20 14.41 18.2 8.40 8.68 7.98 25.06 0.88 0 0.42 1.30 19.7 0.42 0.42 0 0.85 2.0 0 2.70 0.88 3.58 4.92 0.50 1.18 74.5 7.6 17.9 18.11 15.52 9.18 42.3 36.3 21.4 22.26 23.53 17.05 1.34 0.50 0 1.84 2.26 0 0 2.26 0.44 0 0.76 .1,.20 6.60 42.81 % 62.84 LV 0\ \.0 �370 a marked decrease in river channel (Table 18). The 1938 photos depict a broad shallow sandy stream with extensive unvegetated sandbars. The 1935 flood may have been partially responsible for the broad channel. The Arikaree to the north where u.s. Highway 385 crosses at present typifies the appearance of the South Republican at the sampled location in 1938. No reservoirs occur on the Arikaree River. The impact of Bonny Reservoir and controlled water releases during the last 37 years have greatly altered the channel appearance downstream. Both perennial grasses and trees occupy what formerly was river channel and there is evidence that the narrow stable stream has deepened. Thirty-meter wide stream cross-section profiles obtained below and above Bonny Reservoir in Yuma County indicated the average depth was 6.6 dm below Bonny and 4.5 dm upstream (P <0.01). The 7 deepest measurements/sample averaged 7.7 dm upstream and 13.6 dm downstream (p <0.001) providing additional evidence of downstream channel deepening. Stream width averaged 15.4 m upstream from Bonny Reservoir vs. 5.4 m in downstream locations (P <0.001). Livestock grazing, which tends to erode streambanks and flatten channels was present in all upstream and downstream locations. Shrubs declined extensively from 1938 to 1961 and increased slightly from 1961 to 1975 (Table 18). Field inspections within recent years indicated shrubs (mostly Salix sp.) were a minor vegetation type restricted primarily to a narrow band along the stream channel and were moderately to severely impacted by'livestock. A few tamarisk were scattered at the lower end the CDOW Hale Ponds Property but were not healthy and apparently were not. increasing in number. A few indigo bush were also present. Russian-01ive, while still a minor species, has apparently increased. This species was common above Bonny Reservoir. In contrast to shrubs, the area occupied by plains cottonwoods increased dramatically since 1938 when few trees were present. Based on age class data for 1961 (Table 19), most of this increase apparently occurred prior to completion of Bonny Reservoir in 1950 although some production of young trees has occurred since the dam was built. Floods in 1935 and 1947 may have been responsible for establishment of some stands but the exact ages of the trees is unknown. Several factors could have induced additional cottonwood establishment since completion of Bonny Reservoir in 1950. Bonny Creek, which drains into the inventoried section of the river may have flooded. An irrigation ditch which extended from Bonny Reservoir to Bonny Creek. (Fig. 10) was completed along with the reservoir and irrigation drainage may have stimulated cottonwood establishment. It is also possible that spillway releases from the reservoir may have occurred in the 1950's promoting temporary high water or flooding. Age class comparisons (Table 19) indicated that production of young cottonwoods apparently declined to nearly zero in recent years with a trend toward older trees. Changes in canopy cover did not markedly change from 1961 to 1975. Plains cottonwood was by far the dominant species although a few peachleaf willows, primarily old trees, were present. Livestock grazing along the stream has been conducted primarily during growing seasons for many years and has severely impacted tree and shrub reproduction, and growth of shrubs and herbaceus vegetation. Most sites have poor horizontal and vertical diversity because only 2 covers, trees and grazed grass, are present. �371 Establishment and Survival of Cottonwoods Under Natural Conditions Intensive Transects.--The inventory suggested that cottonwoods and willows along riverbottoms in Colorado have not been reproducing in recent years due either to lack of seed germination, lack of seedling survival, or both. Therefore, seedling survival and the factors influencing it were examined. Flood conditions in 1983 and 1984 along the South Platte River (Fig. 11) caused by melting of extensive snow accumulations in high mountain headwater areas provided ,conditions suited for documenting natural reproduction and monitoring seedling survival. Cottonwoods and willows are both early successional, pioneering plant groups which are intolerant of shade have shallow root systems, normally must grow at sites close to the water table, and which have narrow requirements for natural reproduction including exposed (bare with little competition), wet soil (Christy 1973, Baker and Broadfoot 1977, Fitzgerald 1978, Snyder and Bovee 1983) short-lived seeds are released in conjunction with late spring-early summer peak streamflows. When streams overflow their banks, sediments picked up and carried, or scoured out of the channel are deposited in slow-moving backwaters where alluvial deposits (primarily silt and clay) accumulate (U.S. Dep. Inter. 1981). Persistent high water may kill, stunt, or cover existing vegetation leaving an exposed site for seed g~rmination. Slow declines in water levels along streambanks and side channels may leave an alluvial deposit containing seeds from which narrow, linear stands of new seedling germinate. Based on data from Sedgwick and Knopf (1988) and U.S. Geological Survey Water-Data Reports for Colorado, average South Platte river flows in 1983 and 1984 were the highest recorded in 80 years. River flow in 1983 was especially conducive to establishment and survival of cottonwood and willow seedlings because the river reached and maintained a low flood stage through May and June lowering slowly in July (Fig. 11). This prolonged inundation of perennial herbaceous vegetation retarded its growth and covered many perennials with silt deposits resulting in extensive mudflats. At the same time, seed production of cottonwoods and willows was retarded by below average temperatures through April, May, and June. Their seed disseminated slowly from late June into July as river levels slowly decreased. The result was extensive seedling germination, often in vast dense mats. The South Platte remained higher than normal through the 1983-84 fall-winter interval and increased to low flood stage again in May (Fig. 11) •. Many seedlings established in 1983 were inundated and lost. Flows decreased rapidly in late June 1984 and many seedlings on higher sites were desiccated by dry, late-summer conditions. As a consequence, within 11 preliminary transects established in late summer 1983, seedling survival to early fall 1984 was only 2.2% and 100% mortality occurred within 6 of 11 transects. Seedlings germinating in 1984 were primarily in linear bands along main stream and side channel locations at lower elevations than those established in 1983. Some were probably lost during sporatic flows in fall-winter 1984. Seedlings of peachleaf, coyote, and sandbar willows were generally less abundant than those of cottonwoods but were common following 1983-84 high stream flows. Seedlings of frost grape, green ash, and Russian-olive were less common and primarily were observed following high water in 1983. �372 400 ~ . t\ •• I •\ I \ • .\ . ,;.\ ,·v I' "'" 300 , .II -- \ !._" \ •• \ I \ I J 1 ,. , • • •• • · 1 , r ,. ~, ··· I tI'] <, rt'\ ~ ...•• 200 , • :3 ~• 0 • ~ FLOOD STAGE - ~ ~ tI'] 100 50 ., 11 MAY 21 . 1 11 JUN 21 1 11 JUL 21 1 AUG Fig. 11. Stream flow (m3/s) averaged over 5-day intervals at Julesburg during years within recent decades when the South Platte River flooded. �Table 20. Site Cottonwood seedling density along transects from fall 1984 through 1987, South Platte River, Colorado. Transect II Status Samp1es/ transect Grazed Ungrazed Ungrazed Ungrazed Grazed Grazed Grazed Grazed Grazed Ungrazed Ungrazed Ungrazed Ungrazed Ungrazed Ungrazed Ungrazed 25 9 25 25 25 20 7 17 25 25 16 25 25 25 25 25 1984 Total seedlings 1985 1986 1987 1984 5 14 1 0 8 0 5 90 66 2 65 34 0 47 15 179 2.76 9.11 1.12 0.12 2.16 1.35 5.00 10.12 7.96 0.52 5.75 2.04 10.72 2.68 21.33 Mean density/m 1985 1986 1987 Seedlings established in 1983 Sedgwick Bar Haxtun R&G Tamarack Bravo Tamarack Brush X density 4 2 4 2\07 4W1 4W2 4W3 6W1 6H2 21W 22W 24w 1 2 9Wa 1 69 82 28 3 54 27 35 172 199 13 92 51 268 67 48 29 24 4 1 26 3 24 129 119 8 81 44 0 54 27 226 26 14 1 0 13 0 12 99 85 4 75 37 0 54 33 184 3.31 1.16 2.67 0.16 0.04 1.04 0.15 3.43 7.59 4.76 0.32 5.06 1.76 0 2.16 12.00 9.04 3.21 1.04 1.55 0.04 0 0.52 0 1. 71 5.82 3.40 0.16 4.69 1.48 0 2.16 14.67 7.36 2.79 0.20 1.55 0.04 0 0.32 0 0.71 5.29 2.64 0.08 4.06 1.36 0 1.88 6.72 7.16 2.00 14.40 3.36 8.78 41. 78 86.67 31.33 96.00 148.44 47.11 53.10 0.08 0.04 2.83 0.44 42.22 5.89 31.11 16.44 27.56 14.07 0 0 2.17 0 42.22 4.56 (>.67 4.89 19.11 8.85 0 0 1.83 0 44.00 3.92 1.25 0.92 9.84 6.86 Seedlings established in 1984 Tamarack Bravo Sedgwick Bar Haxtun R&G Tamarack Jones X density 13W1 13W2 3 5a 3a 2Ea 6\073 a 6w4a 3a Grazed Grazed Ungrazed Grazed Ungrazed Ungrazed Grazed Grazed Ungrazed 25 25 18 25 25 17 20 25 25 360 84 158 94 195 48 216 334 106 2 1 51 1 95 9 56 37 62 0 0 39 0 95 7 12 11 43 aSamples obtained with a 0.09-m2 frame and corrected to m2 density. 0 0 33 0 99 6 2 2 22 w ---.J w �374 Plains cottonwood seedling survival within 24 randomly selected intensive transects established in 1984-85 and monitored through 1987 was variable (Table 20). Sixteen of the transects were dominated by 1983 seedlings and 9 by 1984 seedlings. Livestock grazed within 11 of the transects sometime during the year. Once transect had total mortality in 1985 when a sand dam was constructed upstream diverting stream flows to the main channel on the other side of the riverbottom. All cottonwoods died within 4 other transects in 1986 but 80% of the transects sustained at least some survival throughout the 4-year moni~oring interval (Table 20). Table 21. Mean survival rates (%) of cottonwoods seedlings within intensive transects, South Platte River, northeastern Colorado, 1984-87. Year of establishment 1983 1984 Survival rate, Sep to Sep 1984-85 1985-86 1986-87 47.4 19.7 79.1 65.9 77.7 79.4 3-yr survival rate 29.1 10.3 Seedlings established in 1983 within transects sampled in late summer 1984 had already survived through the last half of 1983 and most of 1934. Thus, major attrition had already occurred (2.2% survival). Sedgwick and Knopf (1988) reported <25% survival over the same interval among 300 tagged seedlings within their SP\~ study area. First-year survival among seedlings established in 1984 to early fall 1985 was 19.7%. Subsequent survival among successive years remained much higher, ranging from 47.4 to 79.1% (Table 21). The 3-year survival rate for 1983 seedlings were 29.1% compared to 10.3% for 1984 seedlings. Mean density Cm2) varied greatly among transects and among years (Table 20). Among 1983 seedlings, density declined to 2.0 seedlings/m2 by fall 1987; seedling density in 1987 on 1984 transects was 6.9/m2 (Table 20). Attrition and thinning through browsing, competition for space, and other factors was expected. It was more important that at least a few seedlings/transect survived for several years because chances of survival to maturity increased with each successive year and that seedlings were well distributed along the riverbottom. By fall 1987, surviving 1983 seedlings had obtained considerable growth, however height varied widely among transects apparently because of varying soil quality. In better sites seedlings averaged 2-3 m tall with some to 4 m. In poorer sites heights ranged from 0.5 to 2 m. Most mortality was attributed to desiccation during the first 2 growing seasons. Among 1983 seedlings extensive desiccation occurred in July-August 1984 as stream flows declined. Additional mortality attributed to desiccation was noted in late summer 1985. Broadfoot (1973) reported that soil moisture �375 must be available within 30-46 cm of the soil surface for the first year of seedling growth. Thus, the water table must be close to the soil surface with moist soil extending above it. Finer soils containing silt and clay appeared to retain moisture much better than coarse sands and gravels. This may be a major factor in the apparent better seedling survival and growth in sites containing better soils. Sedgwick and Knopf (1988) found soil moisture at sites containing germinated seedlings was greater than for random sites where no seedlings were present. The alluvial flood plains where cottonwoods and willows occur show little or no soil profile development and contain alternating bands or lenses of sand, silt, clay, and gravel with little humus (Lindauer 1970, Christy 1973). Extensive soil monitoring along the South Platte River showed most soils contained a high proportion of sand, a high pH (8.0), and moderate to high soluable salt content (Christy 1973). Sedgwick and Knopf (1988) found no relationship between cottonwood seedling establishment and 13 edaphic characteristics including soil pH, organic matter, and several soil nutrients (nitrogen, phosphorus, potassium, zinc, etc.). These findings imply that soil type and quality are usually not important considerations in seedling establishment. Moisture, not soil is the key factor in germination and survival. Crouch (1979) cited references stating that cottonwood seed required bare·, moist, mineral soil for germination. Sedgwick and Knopf (1988) found that germination in 1984 occurred under a widely varied conditions including areas where plant cover «1.0 m high) exceeded 95% and litter cover was >75% •. However, their data showed germination was more successful in areas where plant and litter cover was low. Likewise, seedling survival was lower in sites with increased litter, increased tall plant cover, and increased short plant cover. Survival was positively correlated with increased bare ground. They listed several factors including competition as responsible for a negative relationship between cottonwood seedlings and herbaceous cover. Numerous seedlings germinating in 1983 survived to 1987 in relatively thin stands distributed over ungrazed meadows on the SPw~ that contained dense herbaceous vegetation. Herbaceous cover had not been silted over or subjected to prolonged inundation during the 1983 flood. Many seedlings in these sites were subsequently lost to noxious weed control. This illustrates that moist soil is the primary requisite for cotton,mod seedling establishment. Several small sites within a proposed late winter 1986 controlled burn on the Brush Wildlife Area contained cottonwood seedlings established in 1983. One 25-m transect was established and monitored prior to and subsequent to burning. First-year post-burn survival was about 81% indicating that, although most seedlings had been burned to the ground, regrowth of seedlings was common. Favorable survival (97%) was recorded in 1987 (Table 20). Livestock also impacted cottonwood seedling survival on the transects. Seven transects were exposed to moderate winter cattle use in 1983 and 1984. Dormant seedlings were not noticeably browsed but some trampling of seedlings probably occurred. Sedgwick and Knopf (1988) observed first year (1983-84) fall to fall seedling survival at 2.6-18.5% within these and other moderately grazed winter plots whereas seedlings within ungrazed plots survived slightly better (3.2-27.4%). �376 Two transects containing 1984 seedlings were subjected to more intensive winter livestock use. Trampling and desiccation were the primary causes of 100% mortality on both transects. One other transect received summer livestock use in 1985 when low stream flow permitted cattle to cross the river. Extensive browsing was noted on the seedlings and mortality in 1985 approximated 80%. Surviving seedlings remained alive from basal regrowth in 1986 but were severely stunted. Observations indicate cottonwood seedlings are readily consumed by livestock when the plants are leafed out. In addition they are readily browsed by cottontails (Sylvilagus spp.), deer (Odocoileus spp.), and beaver. Based on these data, it evident that cottonwood seedlings may survive under light winter grazing when the seedlings are dormant. However, with spring through early fall livestock use, there is little chance for survival. Extensive Transects.--Preliminary sampling of cottonwood seedling occurrence over extensive areas was conducted within several walking transects on Division of Wildlife Properties along the South Platte in early fall 1983. Seedlings were found within 14.8% of 1,055 m2 samples. Thirty extensive random transects, distributed from the Nebraska-Colorado boundary upstream to Atwood were established in 1984 and were sampled in early fall from 1984 to 1987. New cottonwood seedlings were recruited into the samples during all 4 years and ages of older seedlings became progressively more difficult to determine. However, seedlings established from 1985 ·through 1987 occurred in low areas subject to frequent inundation and their chances of long-term survival were minimal. Attrition of older seedlings was noted and, whereas they represented 1.9% occurrence in 1984 they probably represented less than 1% occurrence in 1987 (Table 22). The number of transects containing cottonwood seedlings also declined over time. J Table 22. Number, age, and frequency of occurrence (%) of cottonwood and green ash seedlings within 30 random transects along the South Platte River, northeastern Colorado, 1984-87. Year 1984 1985 1986 1987 Co ttonwoo d Year established 1983 1984 1985 Total 22 5 10 12 l7a 17 9 21 8 32 26 38 2Sa % occurrence Transect m2 1.9 1.5 1.9 1.3 56.7 43.3 53.3 30.0 Green ash % occurrence Total m2 Transect 4 9 12 34 0.24 0.51 0.60 1.74 10.0 16.7 23.3 40.0 aAges of seedlings could not be accurately determined in 1986 and 1987. b1985 or later. In contrast to the decline of cottonwood seedlings, those of green ash, considered more mesic in adaptation, increased with time within the transects CTable 22). This species was represented by few, if any, old trees along the river but a few young to medium age trees were present. Green ash were found within 12 of 30 transects in 1987. Sedgwick and Knopf (1988) summarized reasons why this species (referred to as red ash) seemed to the most probable �377 species for future overstory dominance along the South Platte. Personal observations strongly support their hypothesis. Observations in Nebraska indicate green ash usually form dense closed canopies so that little understory vegetation exists, however, old trees contain numerous cavities. Russian-olive seedlings were found twice in 1987 transects and were observed spreading into the floodplain from the SPWMA meadows. Previously, mortalities of 2-3 year old seedlings had been noted as a consequence of prolonged inundation in 1983. Subsequent floods may restrict this species to the outer edges or higher elevations within the South Platte floodplain. Common hackberry (Celtis occidentalis) and silver buffalo berry (Shepherdia argentea) were planted within the Sedwick Bar Property along the South Platte floodplain in western Sedgwick County in the early 1950's. Little or no natural regeneration and spreading of these species has been observed in adjacent or downstream locations. A few other exotics occur along the South Platte including silver poplar (Populus alba) but none has shown evidence of becoming a major invader. One Juniperus species was recently reported growing wild within the SPWMA (M. Gardner, Pers. Commun.). Supplementing Natural Reproduction Cottonwoods, willows, and several other woody species including grape vines can be propagated by use of hardwood cuttings (Doran 1957, u.S. Dep. Agric. 1965). This technique has been used successfully in the southwestern United States (U.S. Dep. Agric. 1983, Swenson and Hullins 1985, York 1985). Therefore, evaluations of this technique were conducted to ascertain if stem cutting propagation could be used effectively to supplement natural reproduction along Colorado's rivers. trials were begun on the SPWMA in late winter 1984, primarily using cuttings from the previous year's growth. Stem cutting survival to mid summer appeared good but survival to early fall varied widely among species and was poor (Table 23). Stem cutting efforts were expanded to several additional locations along the lower South Platte, South Republican, and Arkansas rivers in 1985. Good survival occurred to early summer but survival was poor to early fall (Table 23)~ Plant vigor and growth among survivors also was poor and few survived until spring 1986. Reasons for poor survival were uncertain but 3 primary factors were suspected. First was competition with herbaceous vegetation present at most locations. Second was unstable ground water levels that rose to near the soil surface in late spring and decreased rapidly in mid summer when irrigation demands reduced stream flows. Within the Arkansas Valley, the water table rose to drown most of the 1985 cuttings placed there. The 3rd suspected reason for poor survival was that cuttings had not been placed deep enough and groundwater levels in mid to late summer fell below the average depth at which cuttings were placed (Fig. 12). Planting methods were modified in 1986, primarily on the SP~lliA,to identify which of the 3 variables impacted stem cutting survival. Preliminary �378 Table 23. Survival of stem cutting plantings from late winter to early fall within the South Platte, South Republican, and Arkansas River planting sites, 1984-86. Species Populus sargentii Salix amygdaloides S. interior!exigua lutea S. vitellina Amorpha fruiticosa Vitis vulpina Parthenocissus quinquefolia s. Annual total/average Planted 1984 Survival Planted 1985 Survival Planted 1986 Survival 31 6 12 35 39 15 12 4 0.35 0 1.00 0.43 0.59 0.13 0 0 80 40 53 70 15 55 40 20 0.11 0.05 0.26 0.04 0.87 0.27 0.12 0.05 34 24 5 33 5 30 13 0.41 0.29 1.00 0.52 0.60 0.50 0.31 154 0.41 373 0.17 144 0.45 Average planting depths of 10 dm in 1985 were increased in 1986 to range from 17.1 to 19.5 dm whereas lowest groundwater levels were in the 12-15 dm range (Fig. 12). In addition, two-thirds of the 1986 cuttings were placed within sites overlaid with a plastic-organic mulch (Snyder 1983) to eliminate competition with herbaceous vegetation. Groundwater levels were monitored more frequently to detect variations. Among the tree, shrub, and vine species tested all but one, golden willow tSalix vitellina), were native species which previously had shown promise of being able to survive as stem cuttings. Several other species, including New Mexico elderberry (Sambucus neomexicana), cotoneaster (Cotoneaster sp.), and Russian-olive, which had shown little evidence of survival, were not included in 1986 evaluations. Survival to fall among 97 plantings where herbaceous vegetation competition had been eliminated with mulch was 52%, whereas survival of 47 unmulched cuttings was 32% (P < 0.10). This provided evidence that competition was at least a partial factor reducing stem cutting survival. Survival among unmulched cuttings was 34% in 1986 compared to 22% in 1985 among the same combined species within the same locations. This provided little evidence that increased 1986 planting depth markedly enhanced survival. Attrition continued among the 1986 cut,tings over winter and by late summer 1987, only 33% of those surviving to fall 1986 were still alive. Other factors including browsing of new leaves by deer and/or cottontails in 1986 were possibly important. However, the evidence indicates that fluctuating groundwater was the primary variable contributing to low survival of stem cuttings. New roots forming in moist soil above the water table might be repeatedly inundated and desiccated and therefore severely weakened or killed, and the new cuttings had only limited energy reserves. Swenson and Mullins (1985) noted reduced survival among cuttings placed in fluctuating water tables in their New Mexico trials. Another factor making stem cutting planting questionable was the difficulty encountered in placement of cuttings into the water table. When planting was �o CHECK STATION 2 - TAMARACK MEADOW 11-E 4 en a: w I- w 6 ~ I (.) w o ...., J: Ia. w o a: 8 \ I \ I \ I \ , \ 10 w , ,, I I- « :r: ,•... .. , ', ,, ,, , ,, , ,, ,, ,, ,, " ,, ,, 12 ,I I ' ,,, • ,, , I I I " I , . ,,, , " ,, , , ,, '' • . ," ,, ,,, , I I , , \ \ \, " ," , I ,, , ,, ,, , ,'", I I , , , I , ,,, ,,, ,, , , I " ,, , , , , I I I . '--' I , ,, ," , ,, I ••I , 14 , " ,I , I I I I I \ I " , ,, , , ', • ,, ,, , ,' , ',, ,, ,, ,, , ,, , , ,, ,, " , ,,, , I , \'•' I I , ' ,_' , ,, I ,, ,, , .•. , I , I If • " 16 J F M A M J J A SON D J F M A M J 1984 Fig. 12. Groundwater fluctuations within stern cutting lower South Platte River, northeastern Colorado. J A SON D J F M A M J J A SON 1986 1985 planting D sites from 1984 through 1986 along the LV --..J \.0 �380 done in March, water tables were moderately high so that it was essential to place the cuttings several dm deeper to be positioned below the lowest late summer water levels (Fig. 12). However, when digging holes for the cuttings the sands would collapse preventing further penetration as soon as the water table was reached. A retaining sleeve (casing) had to be inserted and repeatedly forced down as the sand was extracted with a hand auger and the stem cutting had to be inserted before the sleeve was removed. This procedure was labor intensive and too costly to be practical on an extensive scale. Svoboda and Graul (1980) recommended scouring 15 x 30 m strips about 2-dm deep with a D-8 dozer blade in late fall or early spring to remove competitive vegetation permitting the natural establishment of cottonwoods. A dozer blade was not available for use during this study but a small tractor and rototiller were used to remove competitive herbaceous vegetation from 18 randomly selected sites within 6 locations on the SPWMA in 1984. Three additional disturbed sites along a pipeline installed in October 1984 were included in the test. In early summer 1985, cottonwood seedlings were observed on 3 of the sites but all other locations were too far above the water table to sustain moist soil conditions essential for seed germination. Decreased mid-summer river flows caused desiccation of all seedlings within the 3 sites. Sites were maintained weed free into the 1986 growing season but low groundwater levels, due to reduced river flows, again prevented seedling germination. Increasing problems with control of noxious weeds forced abandonment of this experiment. Most of the tilled sites were proximal to cottonwood seedlings that had established in 1983 indicating that if high sustained stream flows had occurred, the results would have been dramatically different. Understory Vegetation Along the South Platte River Natural Occurrence.--A frequency of occurrence index showing the relative abundance and importance of different vegetation and ground cover types was derived from the 30 extensive transects along the South Platte River from 1984 to 1987 (Table 24). Perennial grass was the dominant cover during all years with annual and biennial forbs ranking 2nd in 1984 and 1985, and perennial forbs ranking 2nd in 1986-87 (Table 24). Annual grasses, primarily Bromus spp., like annual forbs, showed declining trends through the 4 years. Low shrubs, primarily snowberry and poison ivy, and tall shrubs, primarily sandbar and coyote willow, were nearly equal in occurrence. In combination they comprised 20-25% of the dominant cover. Grape vines frequently were encountered and often were associated with patches of low shrubs whereas Virginia creeper (Parthenocissus quinquefolia) was infrequently encountered. During sampling within the SP~1A in 1972-73 (Snyder 1978), grasses represented 40% occurrence compared with 24% forbs, 20% brush and vines, 5% litter, and 11% sandbars or bare ground. These data (Table 24) show that vegetation along the lower South Platte was not only diverse in growth form, but was also interrupted by sand bars and bare ground increasing edge and interspersion (horizontal diversity). Overstory trees provided additional vertical diversity enhancing the quality of the riverbottom for wildlife. �381 Table 24. Frquency of occurrence (%) of major cover types within random transects along the South Platte River, northeastern Colorado, 1984-87. Year 1984 1985 1986 1987 Forbs 24.8 14.9 11.6 5.0 Grasses 12.0 8.0 13.7 19.1 9.1 8.4 4.4 5.3 25.0 32.9 37.1 37.7 Shrubs Low Tall 9.7 12.7 11.4 12.2 10.9 11.4 11.2 12.8 Vines Litter 2.0 2.3 1.9 2.1 5.8 7.6 Sand bar 0.7 1.9 1.6 1.2 7.1 4.8 aAnnual forbs include some biennials. bperennial grasses including common reed (Phragmites communis). CLitter includes downed timber and sand bar includes bare ground. As a consequence, of 1983 flooding, mud flats and sand bars were numerous. Limited fall 1983 sampling indicated about 15% of the area was bare. Stream flows were neither as high nor as prolonged in 1984 allowing initial recovery of herbaceous vegetation. The transition from annual and biennial forbs, and from total annuals (forbs + grass) toward perennial forbs and grasses through the 1984-87 interval was highly evident (P < 0.1, Table 25). Occurrence of annuals and perennials was nearly equal in 1984, each representing about 1/3 of the total composition. However, by 1987 perennials dominated 57% of the samples whereas annuals represented only 10%. Although pre-flood vegetation occurrence data were lacking it seems apparent that 1983 flooding promoted major regression of vegetation toward early seral stages. Host perennials were stunted rather than killed allowing for their rapid recovery. Table 25. Frequency of occurrence (%) of dominant annual and perennial herbaceous vegetation in m2 samples within extensive transects along the South Platte River, northeastern Colorado 1984-87. Year Forbs 1984 1985 1986 1987 24.8 14.9 11.6 5.0 Annuals and biennials Forbs + grasses 33.9 23.3 16.0 10.3 Perennials Forbs + grasses 37.0 40.9 50.8 56.8 These data illustrate that 1983 flooding by its scouring, silting, inundation, and general disturbance of bottomlands dramatically promoted production of annual herbaceous vegetation in addition to cottonwood reproduction. Food habits studies (l1artinet a1. 1951) have demonstrated that seeds of annuals are the primary food of a majority of wildlife species, especially upland game �382 and passerines. In riverbottoms, where flooding has been eliminated, e.g., below reservoirs, conversion to perennial grass monocultures occurs rapidly so that much of the food base essential for wildlife species richness (numerous species) is lost before the vertical and horizontal diversity, promoted and sustained by flooding, is lost. Disturbance Tillage.--Along the lower Sout.hPlatte River where flooding still occurs, numerous grass-dominated areas, usually elevated above the normal flood plain, occur which are seldom flooded. Disturbance tillage of narrow linear strips within these areas has been recommended to promote food producing wild annuals for northern bobwhite and other game and nongame wildlife (Rutherford and Snyder 1983). Personnel responsible for managing several CDOW properties along the lower South Platte have implemented limited disturbance tillage. Fireguards plowed out of grass sod and then disced to create mineral soil fire barriers also provided additional disturbance tillage strips. Frequency of occurrence sampling within 7 disturbed strips in fall 1986 and 1987 revealed major enhancement of annuals (Table 26). Annuals were not promoted as dominants in 1986 within one disturbance tillage site where snowberry and poison ivy dominated prior to plowing. These species resprouted profusely to retain dominance and suppress growth of annuals. Annuals dominated among samples in 4 of 5 other sites in 1936 and were common in all. Averaged among sites, annuals dominated 48.2% of the 1986 samples whereas .biennials dominated 25.3% and perennials 26.5%. Table 26. Frequency of occurrence (%) of annuals (A), biennials (B), and perennial (p) herbaceous vegetation within disturbance tillage strips, South Platte River, Northeastern Colorado 1986-87. 1987 1986 Location Brush Wildlife Area 1-86 2-86 1-85 2-85 Elliott West East Tamarack Interior Exterior P N A 17.7 39.7 23.1 19.4 12.7 9.5 18.4 49.3 70a 68a 50b 50b 31.4 30.9 36.0 54.0 55.3 42.6 2.1 40 75 100.0 100.0 30.9 14.6 25.0 54.4 75.0 40a N A 79 63 65a 67a 69.6 50.8 58.5 31.3 47 55 16 0 B 10.0 P B 27.2 10.3 12.0 8.0 41.4 58.8 52.0 38.0 0 0 0 0 40.0 50.0 aSampling was conducted 2 growing seasons after disturbance tillage. bSampling was conducted 3 growing seasons after disturbance tillage. �383 Among the annuals sunflower (Helianthus sp.) was the most frequent dominant often averaging 1.9 m tall and provided food as well as cover. Annual ragweed (Ambrosia trifida) and lambsquarter and orache (Chenopodium spp.) were less abundant but provided excellent food-tall cover combinations where present. The majority of 13 annuals, rated as dominants in one or more samples we~e considered good seed sources for wildlife whereas only western ragweed (Ambrosia psilostachya) of 12 perennials was considered important (Martin et al. 1951). A rapid transition to dominance by perennials was noted in 1987 within the Brush and Tamarack sites as disturbance tillage was not repeated and successional progression occurred (Table 26). Among 4 sites within the Brush Wildlife Area, annuals averaged 1.3 m in 1986 and 1.2 m in 1987. Biennials were 1.0 m tall both years and perennials averaged 0.7 m in 1986 and 0.5 m in 1987. In addition to being an excellent food source, annuals usually have improved height, they·remain erect, and usually retain an open understory making them an excellent food-cover combination for wintering wildlife. Prescribed Burning Within Riverbottom Prescribed burns were conducted by CDOW management personnel on several bottomland meadow sites along the South Platte River in early spring 1985 and 1986. Their primary objectives of removing dense matted residual cover and stimulating new growth of perennial grasses were achieved. Within the burned sites, average height-density indices (HDI) (Robel et al. 1970) increased from 0.57 to 1.25 dm respectively from late winter pre~ to postburn intervals. ~·lithinproximal unburned controls, HD Lncreaaed at a slower rate (0.35 to 0.61 dm, P< 0.05). Burned sites remained dominated by perennial grasses but first-year enhancement by fire of sunflowers, sweet clover (Melilotus spp.), and other forbs was noted. Although fire opened the herbaceous cover allowing increased use by wildlife in spring and summer, grass stands in fall and winter appeared generally as dense and difficult for small wildlife to penetrate as they were prior to burning. Early fall observations indicated most wildlife were concentrated along the forb-dominated firguards. A few plains cottonwoods, peachleaf willow, sandbar willow, indigobush, and other woody species were present in areas burned in 1985 and 1986. In 1985 most trees and shrubs were subjected to a rather intense headfire whereas in 1986 suppressed backfires were set around most mature trees. Among 34 primarily mature plains cottonwoods subjected to fire in 1985, 53% were not markedly impacted whereas 32% were moderately impacted (considerable basal scorching and branches killed to above 2 m) and 15% were severely impacted or killed. Six of 11 peachleaf willow, which were smaller trees than the cottonwoods, were severely impacted. The peachleaf willows root sprouted and sent up new growth to 2 m whereas no basal sprouting among mature cottonwoods was noted. Young cottonwood seedlings that had germinated in 1983 were burned off in both 1985 and 1986 fires but most resprouted to resume growing. Three of 4 young Russian-olive trees were entirely scorched by the 1985 fire. Resprouting was noted from basal interior areas but regrowth was not vigorous. Among shrubs, indigobush amorpha, and snowberry both showed rapid regrowth during the first growing season. In contrast sandbar willows appeared more severely impacted by fire and their regrowth was marginal. Regrowth of Virginia creeper was noted following 1986 burns. �384 Wildfires occur infrequently along the South Platte river bottom and their extent intensity, and the time of year determine their impact on cottonwoods and other vegetation. Postburn surveys of 3 wildfires in recent years show generally moderate damage to cottonwoods. Although the tops of many trees may live, branches close to the ground which provide screening and protection for many wildlife species are lost. Wildfires are more frequent along the Arkansas River and their impacts are much more severe. Many are set intentionally to open stands of tamarisk. However, tamarisk resprouts profusely and rapidly regrows. Observations indicate the burning tamarisk produces intense heat as well as flames that reach several m into the air killing any overstory cottonwoods. As a consequence, the transition from cottonwoods to pure stands of tamarisk is enhanced. Riverbottom Habitat-Wildlife Relationships The direct .impacts of cottonwood riparian habitat quantity and quality on wildlife species richness and density is apparent, but were not studied. However, before changes in quantity and quality of riverbottom habitat can really be meaningful their impacts on wildlife must be known. Past studies (Beidleman 1954, 1978; Crouch 1961; Bottorff 1974; Fitzgerald 1978; Rucks 1978; Ports 1980; Tubbs 1980; Hoover and Wills 1984; Knopf 1985, 1986; Knopf and Sedgwick 1987; Sedgwick and Knopf 1986, 1987, 1988) provide a base of general knowledge conc&rning wildlife species diversity and the importance of the cottonwood riparian ecosystem in relation to other habitats in Colorado and the Great Plains. Much of this knowledge is restricted to the South Platte River in northeastern Colorado and little data are available for wildlife along other Colorado rivers. Several of these references also provide information on densities of certain wildlife species within specific study sites and Fitzgerald (1978) associated densities with plant communities within his South Platte study areas. Apparently, little \wrk has been done in Colorado to relate densities of specific wildlife species to cottonwood riparian habitat quantity-quality indices over extensive areas. Such relationships would provide a basis for identifying the relative importance of specific food-cover associations, importance of vegetation structure, relative importance of plant communities, and the minimum requirements for specific wildlife species. Monitoring among seasons and over time would reveal habitat trends and their impacts on wildlife. Beidleman (1978) and Fitzgerald (1978) stressed the lack of wildlife data for cottonwood riparian habitats and emphasized the importance of broad based studies such as those conducted in Arizona (Anderson et ale 1978, Anderson and Ohmart 1980, 1985). Svoboda and Graul (1980) discussed application of a species-ecosystem approach to managing cottonwood riparian habitats for wildlife. Using this approach management would be directed toward wildlife species which were most sensitive to habitat changes or had the most narrow range of ecological requirements (stenotopic). The goal of species-ecosystem management would be to maintain cottonwood riparian habitats so no species was lost as a functional element of the ecosystem (Graul et ale 1976). However, in reviewing wildlife species present along the South Platte, Svoboda and Graul (1980) found few truly stenotopic species and recommended adding several species with widely separate ecological requirements to the list of stenotopic species so that management goals could be more comprehensive. Lack of stenotopic species along the South Platte was attributed to nearly all wildlife being invaders since development �385 of the cottonwood ecosystem. Knopf (1986) stated that 90% of the contemporary avifauna along the lower South Platte River was not present at the turn of the century. Whereas the general objective in riverbottom habitat may be to sustain or enhance habitats for all existing wildlife, more specific objectives directed toward a single species or group of species may be included under the species-ecosystem approach. However, this assumes no wildlife species will be eliminated by management directed toward another. Miller (1985) summarized initial attempts to implement ecosystem management within 2 CDOW properties along the South Platte River applying the process described in Hoover and Wills (1984). However, to date, little progress has been made toward this type of management within the cottonwood riparian habitats of Colorado. Currently, the northern bobwhite is the only eastern Colorado riparian species which is censused routinely, and for which general density information can be obtained among differing locations and years. Livestock Grazing Impacts on Wildlife Livestock grazing can impact natural regeneration of cottonwoods and willows, especially when conducted during the growing season. Most livestock impacts on wildlife are indirect through their effects on vegetation. Studies have generally shown negative impacts of grazing on wildlife. Crouch (1981) noted dramatically greater numbers of birds and mammals during 15 inven~ories of the ungrazed SPWMA in comparison to a proximal intensively grazed riverbottom. Taylor (1986) found that counts of birds were 5-7 times higher on an area ungrazed since 1940 than on 2 areas grazed annually until 1980, and 11-13 times higher than on a transect severely disturbed by extensive grazing and dredging activities. Total numbers of birds and mammals decreased with increased grazing pressure along streams in western Colorado (Rucks 1978). Numerous other studies have reported similar findings. However, the intensity, duration, and period of grazing influences the impact of grazing on wildlife. Light to moderate grazing during winter, when plants are dormant, does not destroy all cottonwood seedlings and its general impact on riverbottoms is less severe than summer grazing. Sedgwick and Knopf (1988) found that grazing at a moderate rate when vegetation was dormant on a SPWMA study site had no apparent negative effect on 6 migratory birds species that were predominantly insectivorous but foraged and/or nested within the grass-herb-shrub layer of the riverbottom. Their study did not include impacts on more numerous birds using riverbottoms that were primarily weed seed eaters. The first foods generally consumed by livestock are seed heads of herbaceous annuals, if available. Thus, livestock are in direct food competition with numerous wildlife species. Livestock also reduce cover quality and quantity needed by many wildlife species. Fall movements of northern bobwhite coveys from grazed to ungrazed sites for winter survival were noted during population dynamics studies within the SPWMA (Snyder 1978). In Colorado the problem of intensive livestock degradation of riparian habitat is not confined to riverbottoms. Hundreds of intermittant tributaries and small streams could support vast increases in wildlife habitat if livestock were excluded, especially during the growing season. �386 CONCLUSIONS Persons working with wildlife in Colorado should be concerned because stands of cottonwoods, willows, and wildlife habitat are deteriorating along all inventoried rivers. The same trend is probably occurring along other lower elevation streams, although the rate of habitat deterioration varies widely among streams. Among the inventoried rivers, wildlife habitats along the Arkansas River are deteriorating most rapidly and opportunities for curtailing the decline appear dim. Although habitat deterioration along the South Platte and Colorado rivers was evident, declines were at more moderate rates and recent flooding has stimulated regeneration of cottonwoods and willows. Habitat conditions along the Rio Grande River appear more stable. However, resident wildlife managers indicate little new natural reproduction was occurring. The Rio Grande River may be in the early stages of a general habitat decline. Construction of mainstream flood control reservoirs (e.g., John Martin Reservoir) has a devastating impact on downstream riparian habitats. Such reservoirs, by eliminating flooding, and reducing and stabilizing streamflows, curtail nearly all opportunity for natural regeneration of cottonwoods and willows, as well as allowing perennial grasses to increase eliminating food and horizontal diversity needed by wildlife. The river channel narrows and deepens so that its capacity to sustain high stream flows, if they ever occur, is greatly diminished. Construction of the Narrows Reservoir on the South Platte would be especially devastating to dOWF_stream wildlife habitats because few tributaries occur below the proposed dam site and opportunity for downstream flooding would be low. Construction of water storage reservoirs off the main channel would be much less environmentally damaging. Willows and cottonwoods represent seral stages of succession that have expanded along Colorado rivers in past decades, apparently because of man's reduction of peak seasonal stream flows, alteration of stream flows toward stability, disturbance of soils within riparian habitats, and possibly because of elimination of buffalo and wildfires. Willows and cottonwoods are intolerant of shade and are usually perpetuated by disturbance (flooding, soil scarification, etc.) in combination with high groundwater and moist soil conditions. Once willows and cottonwoods become established within a flood plain, flood water flows are slowed and sediments are deposited so that, over several to many successive floods, the ground level gradually becomes elevated above the streambed and the groundwater level. This in turn, reduces opportunity for natural regeneration as willows and cottonwoods tend to not readily perpetuate themselves in the same location. Assuming soil quality and soil moisture are satisfactory, seed sources are available, and livestock grazing permits, shade tolerant mesic tree and shrub species (eastern red cedar, green ash, etc.) invade under cottonwoods to replace them. If these criteria are not met, the site will progress toward perennial herbaceous vegetation. The streamside soil building successional process has probably occurred along most low elevation streams in Colorado and is partially responsible for the current degeneration of cottonwood stands. However, construction of �387 reservoirs to eliminate or reduce flooding, river dewatering for irrigation, invasions of tamarisk, and intensive livestock grazing especially from spring to fall have all severely impacted natural reproduction of willows and cottonwoods along Colorado streams. Natural succession is the primary process along the South Platte supplemented by localized grazing impacts. In contrast, all factors and especially flood control, tamarisk, and wildfires are impacting the Arkansas River floodplain. Cutting of old trees for firewood has also increased dramatically in recent years. The South Platte riverbottom is the only riparian location in Colorado where another overstory species may successionally replace cottonwoods in the near future. Green ash is anticipated as the primary replacement species along the South Platte and in many locations will occur in dense stands. Succession in most other locations will be either toward tamarisk or perennial herbaceous vegetation. Russian-olive may continue to spread along rivers in Colorado as an intermediate rather than overstory species (Knopf and Olson 1984). The probability of this species forming dense monoculture stands remains uncertain. Although Russian-olive, green ash, and other trees may compete with existing cottonwoods for space and water, their reproductive requirements are different than those of cottonwoods. Therefore, direct competition during reproduction and establishment is not considered important. Where dense stands of tamarisk have invaded floodplains, as along the lower Arkansas "aridColorado river drainages, soil deposition during flooding may be dramatically more rapid than in open cottonwood habitats. When soil building is rapid, opportunities for natural establishment of any woody species are reduced. If tamarisk is not perpetuated from root sprouts, such sites will gradually revert to perennial herbaceous vegetation. Available evidence indicates tamarisk is not tolerant of extremely cold temperatures, and therefore, will probably not be a major invasion threat in northeastern Colorado or in high elevation mountainous areas. Tamarisk is directly competitive with willows and cottonwoods during reproductive phases. Once established, there currently is no known economical method of eradicating tamarisk (Kerpez and Smith 1987). The CDOW does not have control over much of the riparian habitat along stream and riverbottoms in Colorado, nor does it have control over stream flows. Therefore, opportunities for management of riverbottom habitats are limited. If demands for outdoor recreation continue to increase while livestock and cropland values remain suppressed, demand should dictate enhancement of bottomlands for harvestable wildlife. The CDOW can assist private landowners in sustaining wildlife oriented habitat. Many hunting clubs already own or lease extensive areas along the South Platte and Arkansas rivers and, with suppressed land prices, conversion of these lands to recreational areas may continue. Fluctuating groundwater levels are the major cause of poor survival of cottonwood-willow stem cuttings. Therefore, stem cutting planting is not an economical method of supplementing natural reproduction. A second deterrent is that below groundwater level in most locations, sands collapse into holes so that stem cuttings can not be readily inserted. Hodified procedures have �388 been described wherein cuttings were inserted behind a high pressure water jet system (Schultze and Wilcox 1985). However, large, expensive equipment would be needed and the approach still is not practical if survival of cuttings can not be increased. Elimination of flooding not only curtails reproduction of woody species but also allows herbaceous perennials to become dominant as seed producing annuals decline. Thus, flooding is of value for the disturbance it promotes which retains seral stages of vegetation succession as well as for its stimulation of natural tree-shrub regeneration. LITERATURE CITED Anderson, B. W. 1985. Managing riparian vegetation and wildlife along the Colorado River: synthesis of data, predictive models, and management. Pages 123-127 in R. R. Johnson, C. D. Ziebell, D. R. Patton, P. F. Ffolliott, and~. H. Hamre, Tech. Coords. Riparian ecosystems and their management. First North American Riparian Conf. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. ~~-120. , R. D. Ohmart and J. Disano. ----~ floodplain for wildlife. Pages 1978. Revegetating the riparian 318-331 in R. R. Johnson, and J. F. McCormick, Tech. Coords. Strategies for-Protection and management of floodplain wetlands and other riparian ecosystems. U.S. Dep. Agr.ic., For. Servo Gen: Tech. Rep. W-0-12. ----- , and R. D. Ohmart. 1980. Designing and developing a predictive model and testing a revegetated riparian community for southwestern birds. Pages 434-449 in R. M. DeGraff, Tech Coord. Management of western forests and grasslands~or nongame birds. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. INT-86. Athearn, F. J. 1985. Land of contrast - A history of southeast Colorado. U.S. Dep. Inter., Bur. Land Manage. Cultural Resource Sera 17. 26lpp. Baker, J. B., and W. M. Broadfoot. 1977. A practical field method of site evaluation for eight important southern hardwoods. U.S. Dep. Agric., Servo Gen. Tech. Rep. SO-14. 3lpp. Beidleman, R. G. 1954. The cottonwood riverbottom community as a vertebrate habitat. Ph.D. Thesis, Univ. Colorado, Boulder. 4l5pp. 1978. The cottonwood-willow riparian ecosystem as a vertebrate habitat with particular reference to birds. Pages 192-195 in W. D. Graul and S. J. Bissell, Tech. Coords. Lowland river and stream habitat in Colorado: a symposium. Colorado Chap., The Wildl. Soc. and Colorado Audubon Counc. Bittinger, M. W., and G. E. Stringham. 1963. A survey of phreatophyte growth in the lower Arkansas River valley of Colorado. Civil Eng. Sect. Colo. Exp. Stn., Colorado State Univ., Fort Collins. 3lpp. �389 Bottorff, R. L. 28: 975-979. 1974. Cottonwood habitat for birds in Colorado. Am. Birds Broadfoot, W. M. 1973. Water table depth and growth of young cottonwood. U.S. Dep. Agric., For Servo Res. Note SO-167. 4pp. Christy, S. 1973. An analysis of the woody vegetation on the South Platte River flood plain in northeastern Colorado. M.S. Thesis, Univ. Northern Colorado, Greeley. 82pp. Crouch, G. L. 1961. Inventory and analysis of wildlife populations and habitat, South Platte River valley. Job Compl. Rep. Colorado Game and Fish Dep. Fed. Aid Proj. W-l04-R-1-2. 68pp. 1978. Effects of protection from livestock grazing on a bottomland wildlife habitat in northeastern Colorado. Pages 118-125 in W. D. Graul and S. J. Bissell, Tech Coords. Lowland river and stream habitat in Colorado: a symposium. Colorado Chap., The Wildl. Soc. and Colorado Audubon Counc , 1979. Long-term changes in cottonwoods on a grazed and an ungrazed plains bottomland in northeastern Colorado. u.S. Dep. Agric., For. Servo Res. Note RM-370. 4pp. 1981. Wildlife on ungrazed and grazed bottomlands on the South Platte River, northeastern Colorado. Pages 186-197 in L. Nelson, Jr. and J. M. Peek. Proc. Wildlife-Livestock Relationships Symp. Univ. Idaho For. Wildl. and Range Exp. Stn. Moscow. Doran, W. L. 1957. Propagation of woody plants by cuttings. Massachusetts Agric. Exp. Stn. Bull. 491. 99pp. Univ. Fitzgerald, J. P. 1978. Vertebrate associations in plant communities along the South Platte River in northeastern Colorado. Pages 73-88 in W. D. Graul and S. J. Bissell, Tech. Coords. 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Wills, Eds. 1984. Managing forested lands for wildlife. Colorado Div. Wildl. and U.S. Dep. Agric., For. Serv., Rocky Mountain Region, Denver, Colo. 459pp. Hopper, R. M. Colorado. 1978. Evaluation of pothole blasting for waterfowl in Colorado Div. Wildl. Spec. Rep. 44. 2lpp. Johnson, R. R., and D. A. Jones, Tech. Coords. 1977. Importance, preservation and management of riparian habitat: a symposium. Agric., For. Servo Gen. Tech. Rep. RN-43. 2l8pp. U.S. Dep. , C. D. Ziebell, D. R. Patton, P. F. Ffolliott, and R. H. Hamre. 1985. reconciling conflicting uses. F~rst North American Riparian Conf. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. RN-120. 523pp. ---,.".Riparian ecosystems and their management: Kerpez, T. ~., and N. S. Smith. 1987. Saltcedar control for wildlife habitat improvement in the southwestern United States. U.S. Dep. Inter., Fish and Wildl. Servo Resour. Publ. 169. l6pp. Knopf, F. L. 1985. Significance of riparian vegetation to breeding birds across an altitudinal cline. Pages 105-116 in R. R. Johnson,C. D. Ziebell, D. R. Patton, P. F. Ffolliott, and H. Hamre, Tech. Coords. Riparian ecosystems and their management: reconciling conflicting uses. First North American Riparian Conf. U.S. Dep. Agric., Servo Gen. Tech. Rep. RM-120. R: 1986. Changing landscapes and the cosmopolitism of the eastern Colorado avifauna. Wildl. Soc. Bull. 14:132-142. ____ , and T. E. Olson. 1984. Naturalization of Russian olive: to Rocky Mountain wildlife. Wildl. Soc. Bull. 12:289-298. J. A. Sedgwick. 1987. Latent population responses ----to, and a catastrophic, climatic event. Condor 89:869-873. implications of summer birds Lindauer, I. E. 1970. The vegetation of the flood plain of the Arkansas River in southeastern Colorado. Ph.D. Thesis, Colorado State Univ., Fort Collins. 99pp. 1983. A comparison of the plant communities of the South Platte and Arkansas River drainages in eastern Colorado. Southwest. Nat. 28:249-259. Nartin, A. C., J. S. Zim, and A. L. Nelson. 1951. American wildlife and plants: a guide to wildlife food habits. Dover Publ. Inc., New York, N.Y. 500pp. �391 McCluskey, D. C., J. Brown, D. Bornholdt, D. A. Duff, and A. H. Winward. 1983 (1984). Willow planting for riparian habitat improvement. U.S. Dep. Inter., Bur. Land Hanage. Tech. Note 363. 2lpp. HcGregor, R. L., Coord. Lawrence. 1,392pp. 1986. Flora of the Great Plains. Hiller, G. C. 1985. Ecosystem management. Wildl. Proj. 86-039-01-1-1. 28pp. Job Final Rep. Univ. Kansas Press, Colorado Div. Nadler, Jr., C. T. 1978. River metamorphosis of the South Platte and Arkansas rivers, Colorado. M.S. Thesis, Colorado State Univ., Fort Collins. l5lpp. Nelson, Jr., L., and J. M. Peek. 1981. Proc. Wildlife-Livestock Relationships Symp. Univ. Idaho For. Wildl., and Range Exp. Stn. Moscow. 6l4pp. Ports, M. A. 1980. Avian density and diversity in four habitat types in Morton County, Kansas. Kansas Ornithol. Soc. Bull. 31(2):17-21. Robel, R. J., J. N. Briggs, A. D. Dayton, and L. C. Hulbert. 1970. Relationships between visual obstruction measurements and weight of grassland vegetation. J. Range Hanage. 23:295-297. Rucks, J. A. 1978. Comparisons of riparian communities· influenced by grazing. Pages 100-113 in W. D. Graul and S. J. Bissell, Tech. Coords. Lowland river and stream habitat in Colorado: a symposium. Colorado Chap., The Wildl. Soc. and Colorado Audubon Counc. Rutherford, W. H., and W. D. Snyder. 1983. Guidelines for habitat modification to benefit wildlife. Colorado Div. Wildl. Rep. 194pp. Schmidt, Sr., R. A. 1983. Management of cottonwood-willow riparian associations in Colorado. Colorado Chapt., The Wildl. Soc., Denver. 53pp. Schrupp, D. L. 1978. The wildlife values of lowland river and stream habitat as related to other habitats in Colorado Pages 42-51 in W. D. Graul and S. J. Bissell, Tech. Coords. Lowland river and stream habitat in Colorado: a symposium. Color~do Chapt., The Wildl. Soc. and Colorado Audubon Counc. Schultze, R. F., and G. I. Wilcox. 1985. Emergency measures for streambank stabilization: an evaluation. Pages 59-61 in R. R. Johnson, C. D. Ziebell, D. R. Patton, P. F. Ffolliott, R. H-.-Hamre, Tech. Coords. Riparian ecosystems and their management: reconciling conflicting uses. First North American Riparian Conf. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. RH-120. Scott, T. G., and C. H. Wasser. 1980. Checklist of North American plants for wildlife biologists. The Wildl. Soc ,, \-lashington,D.C. 58pp. Sedgwick, J. A., and F. L. Knopf. 1986. Cavity-nesting birds and the cavitytree resource in plains cottonwood bottomlands. J. Wildl. Hanage. 50:247-252. �392 , and ---cottonwood --a~ 1987. Breeding bird responses to cattle grazing of a bottomland. J. Wildl. Manage. 51:230-237. , and 1988. Demography, regeneration, and future projections for in R. R. Sharitz bottomland cottonwood community, Pages Wildlife Symp. Savannah and J. W. Gibbons, eds. Freshwater Wetland and River Ecol. Lab. Symp. (In Press). Simons, D. B., R. M. Li, P. Lagasse, and R. T. Milhous. 1980 (1981). Proc: Workshop on downstream river channel changes resulting from diversions or reservoir construction. U.S. Dep. Inter., FWS/OBS 81-48. 348pp. Smith, B. 1980. The South Platte. Colorado Outdoors 29(5):26-31. Snyder, B., and K. Bovee. 1983. Water supply for riparian vegetation. Pages 27-31 in R. A. Schmidt, ed. Management of cottonwood-willow riparian associations in Colorado. Colorado Chap., The Wildl. Soc., Denver. Snyder, W. D. 1978. The bobwhite in eastern Colorado. Tech. Publ. 32. 88pp. Colorado Div. Wildl. 1983. Shrub thicket .establishment in Colorado's High Plains. 'Colorado Div. Wildl. Game Inf. Leaf. 108. 4pp. 1984. Lowland riparian cottonwood studies. Job Pr?g. Rep. Div. Wildl. Fed. Aid Proj. N-4-'R-2. Jan: 295-370. Colorado 1986~ and~. 'Dynamics of cottonwood regeneration. Job Prog. Rep. Colorado Div. Wildl. Fed. Aid Proj. 01-03-045. Apr: 435-454 and 455-473. 1987. Dynamics of cottonwood regeneration. Job Prog. Rep. Div. Wildl. Fed. Aid Proj. 01-03-045 (In Press). Colorado Svoboda, P. L., and W. D. Graul. 1980. Application of the species-ecosystem approach to the lowland riparian zone within the Tamarack Ranch Wildlife Area, northeastern Colorado. Unpubl. Res. Rep. Colorado Div. \.Jildl. 39pp. Swanson, G. A. 1979. The mitigation symposium: a national workshop on ,mitigating losses of Fish and Wildlife habitats. u.S. Dep. Agric., For. Servo Gen. Tech. Rep. fu~-65. 684pp. Swenson, E. A., and C. L. Mullins. 1985. Revegetating riparian trees in southwestern floodplains. Pages 135-138 in R. R. Johnson, C. D. Ziebell, D. R. Patton, P. F. Ffolliott, R. H. Hamre, Tech. Coords. Riparian Ecosystems and their management: reconciling conflicting uses. First North American Riparian Conf. U.S. Dep. Agric., Servo Gen. Tech. Rep. RM-120. Taylor, D. M. 1986. Effects of cattle grazing on passerine birds nesting in riparian habitat. J. Range Manage. 39:254-258. Tipton, R. J. 1939. Conserv. Board. San Luis Valley Project. Unpubl. Rep. Colorado \vater �393 Tubbs, A. A. 1980. Riparian bird communities of the Great Plains. Pages 419-433 in R. M. DeGraff, Tech. Coord. Management of western Forests and grasslands for nongame birds. u.s. Dep. Agric., For. Servo Gen. Tech. Rep. INT-86. u.s. Department of Agriculture. 1965. Silvics of forest trees of the United States. u.s. Dep. Agric., For. Servo Handb. 271. 762pp. u.s. Department of Agriculture. 1983. Pormant stock planting for channel stabilization. U.S. Dep. Agric., Soil Conserve Servo Tech. Notes: Biol. Note 22, Arizona. 4pp. u.s. Department of Interior. 1981. The Platte River ecology study. u.s. Dep. Inter., Fish and Wildl. Serv., Spec. Res. Rep., Northern Prairie Wildl. Res. Cent., Jamestown, N.D. l87pp. Williams, G. P. 1978. Historical perspective of the Platte Rivers in Nebraska and Colorado. Pages 11-41 in \0/. D. Graul and S. J. Bissell, Tech. Coords. Lowland river and stream habitat in Colorado: a symposium. Colorado Chap., The Wildl. Soc. and Colorado Audobon Counc. York, J. C. 1985. Dormant stub planting techniques. Pages 513-514 in R. R. Johnson, C. D. Ziebell, D. R. Patton, P. F. Ffolliott, and R. H. Hamre, Tech. Coords. Riparian ecosystems and their management: reconciling conflicting uses. First North American Riparian Conf. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. RM-120. Prepared bYw1t1~~ Wildlife Researcher C ��JOB PROGRESS REPORT State of: Project: Colorado W-152-R Avian Research 3 Job ----- Work Plan: 21 Job Title: Sandsage - Bluestem Prairie Renovation Period Covered: Author: 01 January through 31 December 1987 Warren D. Snyder Personnel: Warren D. Snyder, Colorado Division of Wildlife ABSTRACT Above average precipitation and warm spring conditions combined. to promote excellent vegetation growth in 1987 within the Tamarack Prairie. However, the potential impact of these conditions for enhancing the quality of the height-density index (HDI) of vegetation will not be known until sampling is completed in early spring 1988. Grass-forb and sandsag~ (Artemisia filifolia) HDI's had not fully recovered by early spring 1987 from controlled burns conducted on sites 1-84 and 3-84. In contrast, grass-forb cover recovered dramatically and fully within 2 years following the 1985 burns (P <0.05) based on spring 1987 HDI sampling. The 1987 HDI of grass-forb vegetation was reduced significantly from 1986 pre-treatment sampling within only 1 of the 3 burns conducted in 1986. These data provide considerable evidence that post-burn precipitation received during the growing season was a major factor influencing grass response to fire within the Tamarack Prairie. Crown cover sampling in August 1987 within the 1984 burns could not detect major vegetation changes other than the reduction of sandsage. Little change among species ~ad occurred since the last (1985) sampling was conducte4.. The amount of dead vegetation and litter remained below pre-treatment levels. Sampling indicated the revegetation strips, seeded primarily to sWitchgrass (Panicum virgatum) in spring 1985, had attained HDI's approaching 2 dm by early spring 1987 within 2 growing seasons. This HDI was >4 times that of grass-forb vegetation within undisturbed prairie. These tracts continued to improve in quality during the 1987 growing season. AnalYSis also documented that tillage-herbicide renovation of sites previously interseeded to tall, warm-season grasses dramatically enhanced these interseeded grasses (p < 0.05). Sampling within a site sprayed with a contact herbicide in June 1985 to reduce the density of sandsage showed that standing dead sandsage still contributed substantially to overall HDI. Perennial forbs continued to increase in frequency after most were killed by the herbicide treatment. Major HDI quality reduction was noted within a tract burned in 1986 within the sandsage spray site. ��397 SANDSAGE-BLUESTEM PRAIRIE RENOVATION Warren D. Snyder _ P. N. OBJECTIVES Test renovation and revegetation techniques for increasing standing residual height-density of grasses, increasing the proportion of tall, warm-season grasses within the composition, and for reducing the quantity of sand sagebrush to <30% canopy cover in an ungrazed sandsage-bluestem prairie on the South Tamarack, South Platte Wildlife Area in northeastern Colorado. SEGMENT OBJECTIVES Monitoring of environmental and vegetation conditions and changes continued as follows: 1. Precipitation was monitored throughout the year supplementing electronic rain gauge data with information from nearby weather stations through the winter months. 2. Soil moisture accumulations, plant phenology, and weather were monitored primarily in spring and especially at time of controlled burns. 3. Visual obstruction (height-density) measurements were obtained on treatments and controls where applicable in late winter and/or early spring prior to green-up. 4. Crown cover, species composition, and frequency of occurrence measurements were obtained from mid-summer to early fall. 5. Photos of treatments and controls were taken in October. Data compilation and writing the annual job progress report was conducted during fall and winter 1987-88. METHODS Approaches used within this study were previously summarized (Snyder 1986a, 1986b, 1987) and are outlined in the Segment Objectives. Segment objective #4 was conducted only within the 1984 burn sites and their controls after being omitted there the previous year. pampling within the 1985 and 1986 burns and their controls will be resumed in 1988. RESULTS AND DISCUSSION Environmental Conditions Precipitation.--The 4 automatic precipitation recorders, placed on the Tamarack Prairie in February 1987, provided meaningful data from April through �398 October. Data for the winter months were obtained from nearby U.S. Weather Service Stations. Two of the recorders malfunctioned (mouse damage, loose wires) for brief intervals during the summer and the collector on 1 site was destroyed and another damaged by deer in fall. Rainfall amounts varied among recorders (distributed within the Prairie), especially from June through September, thus data were averaged to provide monthly totals (Fig. 1). April 1987 was especially dry, however, subsequent rains from May through August were average or above making total 1987 precipitation almost 25% above average and the highest recorded since study initiation (Fig. 1). Except for an extremely hot-dry interval during the last one-half of July 1987, rainfall and weather conditions were favorable for vegetation growth. Precipitation received in October 1986 and February 1987 (Fig. 1) enhanced soil moisture conditions going into the 1987 growing season. April through early July 1987 soil probe sampling revealed good soil moisture conditions throughout the spring - early summer interval (Table 1). Most probe indices averaged over 1 m in depth throughout the interval. Since sandy soils retain about 2.5-3.8 cm of moisture/0.3 m (1-1.5 in./ft.) (D. Smika, pers. commun.), the Tamarack Prairie soils contained >5 cm 2-5 in. of moisture through spring 1987. Table 1. Average soil moisture accumulations based on soil probe samples (m) during spring-early summer 1987, Tamarack Prairie, CoLorado, Location 1 Apr West Tamarack Prairie W. rain gauge Tr. 2-21 Central Tamarack Prairie M. rain gauge Burn 3-84 4-4 3-5 3-85 14-59 2-85 17-54 10-48 3-86 29 Apr 0.7'9- 2 Jun 1.18 0.95 2 Ju1 0.74 1.31 1.26 1.29 1.06 1.17 1.14 0.97 1.35 1.49 1.21 1.24 0.69 0.79 0.57 East Tamarack Prairie E. rain gauge 3-86 24-65 3E-630 Spray Reveg. 112 113 1.29 1.12 1.14 1.00 1.08 Mean 1.21 0.91 ax of 4 samples/site. 6 May 0.86 1.12 0.72 1.01 1.29 1.10 0.74 �399 20 D N s 0 .•...•. .s• 15 0 z S 0 D N 0 H 8 -c ~ ~ 10 u J ~ A J J J J s J A J J A S A ~ a. ~ A S D J M M M A A J 5 M M A A M o F F J Long-term ~ M A M J 1984 1985 1986 1987 Fig. 1. Monthly and accumulated annual precipitation (in.) from 1984 through 1987 in relation to the long-term average, Tamarack Prairie, Colorado. �400 Temperature and Phenology.--March 1987 was slightly colder than normal, however, April was exceptionally warm and dry (Fig 2). May-June temperatures also were above normal promoting phenologically early growth of Tamarack Prairie vegetation. Comparisons of phenological data in 1987 (Table 2) with data from previous years of study show growth was well ahead of that in 1984, when April was colder than normal but slightly behind that of 1985 and 1986 which were both phenologically advanced (Fig. 2). The graphic data (Fig. 2) are believed to closely depict the relative phenological growth of prairie vegetation among years. Controlled burns, planned by management personnel for portions of the Tamarack Prairie in 1987 were cancelled due to equipment problems and dry, warm weather in April that promoted early green-up. These burns have been rescheduled for spring 1988. Their postponement has not impacted this study as no vegetation sampling was planned. Vegetation Sampling and Evaluation on Burned Sites Height-Density Sampling.--The controlled burns conducted in 1984 reduced the visual obstruction (height-density-index = HDI) quality of both grass-forb and sandsage vegetation in subsequent years (Table 3, Fig. 3). Vegetation had not fully recovered on either burn 1-84 or 3-84 by early spring 1987 although the recovery within burn 1-84, dominated by grass, appeared better than that within burn 3-84 where sandsage was much more abundant. Sandsage remained more severely impacted by fire than grass on both sites. Grass-forb, sandsage, and combined vegetation in 1987 remained markedly below pre-treatment (1984) levels (p <0.05) within burn 3-84 (Table 3). Pre-treatment to 1987 differences were not detected within the 1-84 burn. If post-treatment (1985 and 1986) transect means were difference from those in 1987 on the 2 sites, sampling could not detect those differences (Table 3). Within the 3 spring 1985 burns, fire severely reduced the HDI quality of grass-forb vegetation during the first post-treatment (1986) sampling. However, by early spring 1987 grass-forb vegetation had recovered dramatically to exceed pre-treatment levels (Table 4, Fig. 4). The 1987 grass-forb HDI was markedly above 1986 levels (p < 0.05) when tested among transect means and site means using analysis of covariance, and among site means using a paired t test (Table 4.). In contrast, significant (!>0.05) recovery of sandsage from 1986 to 1987 was not detected and as a consequence combined vegetation likewise did not make a significant recovery either among transects or among sites. However, the dominance of grass-forb cover within samples is illustrated by comparable trends of grass-forb and combined cover (Fig. 4). Controlled burns conducted on 3 sites in spring 1986 did not reveal strong evidence that the height-density quality of grass-forb vegetation was markedly reduced following the first post-bur~ (1986) growing season (Table 5, Fig. 5). Some height-density reduction apparently occurred but a difference (p< 0.05) was detected only within the 1986-87 comparison among transects. In contrast, the height-density quality of sandsage was reduced both among transects and among sites (p< 0.05, Table 5). Combined vegetation, dominated by grass-forb cover, was reduced based on analysis among transects, but the reduction could not be detected when comparing changes among site means. �401 TIME BURNED 80 ~ · JUN JUN 70 · JUN JUN MAY 60 - ~ MAY ~ JUN ~ MAY MAY 50 APR · APR MAY ~ APR APR 40 APR MAR MAR MAR MAR MAR 30 Long-term 1984 1985 1986 1987 x Fig. 2. Accumulating monthly average temperatures (F) from March through June, 1984-87 in relation to that of the long-term X, as an index to vegetation phenology, Sterling, Colorado. - �~ o Table 2. N Phenological conditions of selected vegetation during spring 1987, Tamarack Prairie, Colorado. Species 15 Allium textile Artemisia filifolia A. ludoviciana Abronia fragrens Astragalus sp. Cymopteris montanus Evolvulus nuttalianus Lathyrus polymorphus Leucocrinum montanum Mentzelia nuda Opuntia humifusa Penstemon angustifolius Phlox andicola Physalis subglabrata Psoralea lanceolata P. tenuiflora Sphaera1cea coccinea Tradescantia occidenta1is Tragopogan sp. 5-7.6a Basal leafed Agropyron smithii Boutelua gracilis Calmovi1fa longifo1ia Muhlenbergia pungens Panicum virgatum Paspa1um stramineum Sporobu1us cryptandrus Stipa comata Cyperus sp. aVegetation height, cm. bE = early; F = full; L Apr 23 May 29 Jun 18 6 ---2 Headed 0.5 leafed 2.5-5 Headed 0.5 leafed Bloom Fully leafed Bloom 5 5 5-7.6 Fully blooming Bloom 15.2 L.b bloom E.b bloom Bloom 5 2.5 Budded 2.5-5 L. bud L. bloom Emerging E. bloom F.b bloom 7.6-10.1 Bloom Seed Bloom 2.5-5 H.b bloom L. bloom L. bloom 10.1-15 Budding E. bloom 2.5-5 5.1 Leafed 7.6-10.2 Dormant Dormant Emerging Dormant 5-7.6 2.5-5 late; M 12.7-15.2 7.6-10.2 2.5-5 2.5-5 2.5-5 Dormant Dormant Emerging 10.2-12.7 F. bloom medium. F. bloom 5-7.6 7.6-10 E. bloom L. bloom 30 E. bloom Bud L. bloom 5.1 20-25 7.6 20-30 F. bloom 12.7-15 5-7.6 10-12.7 15-20 5-10 10-15 30 10-12.7 10-15 15-20 30-50 10 15 E. head 5 5-7.6 15 10 15-25 25-38 Near bloom L. bloom Bloom 38-50 F. bloom F. bloom Seed 30-38 38-60 50-60 15-20 F. head �403 Table 3. Height-density (dm) means within 1984 burns and their controls during early spring 1984-87 intervals and! values from analysis of covariance testing among years, Tamarack Prairie, Colorado. Vegetation 1984 Year Burned 1985 1986 1987 1984 Control 1985 1986 1987 0.253 0.814 0.334 0.295 0.687 0.355 0.301 0.643 0.368 0.224 0.847 0.309 0.183 0.935 0.531 0.191 0.797 0.503 0.200 1.044 0.629 0.216 0.688 0.424 BURN 1-84 Grass/forb Sandsage Combined 0.256 0.856 0.372 0.134 0.313 0.162 0.232 0.358 0.256 0.208 0.526 0.258 BURN 3-84 Grass/forb Sandsage Combined 0.222 0.827 0.493 F-Va1ue comEarisons 0.021 0.121 0.047 0.106 0.356 0.201 0.077 0.286 0.157 Pre-burn to Eost-burn 84-87 84-85 84-86 Post-burn to post-burn 85-87 86-87 85-86 BURN 1-84 Grass/forb Sandsage Combined 47.5a 40.1a 66.1a 4.24 14.98a 10.51a 0.52 1.28 2.05 8.19a 8.06a 0.02 0.64 0.41 1.48 0.04 1.40 0.01 2.32 0.91 0.14 2.77 4.45 0.00 4.34 4.68 1.46 BURN 3-84 Grass/forb Sandsage Combined ap <0.05. 22.5a 114.1a 187.0a 5.96 35.31a 53.18a 6.62a 13.55a 9.22a �404 0.7 'C.~o\. •••••• ••• co'(\ eA.·· ,'" 0.6 ••••••• 0.5 ••••••••••••• _ 0.4 •• •• •• .... • ..•• •• •• •• • • ....• 1-84 Control ---------- , '-, ...•....•. ...•. 0.3 0.2 0.1 o 1984 1985 1986 1987 Fig. 3. Height-density (dm) of combined residual vegetation in early spring pre- (1984) and post-treatment intervals within the 1-84 and 3-84 burns, Tamarack Prairie, Colorado. �Table 4. Height-density (dm) means within 1985 burns and their controls during early spring 1985-87 intervals with statistical values of relationships.a Site 1985 Treatment 1986 1987 1985 Control 1986 Statistical values 1985-86 1985-87 1986-87 1987 GRASS-FORB 1 2 3 0.507 0.381 0.180 0.138 0.119 0.053 0.419 0.472 0.244 0.374 0.346 0.158 0.325 0.280 0.180 0.322 0.376 0.156 £1,31 Il,3 t 96.62b 49.82b 4.35b 1.59 0.70 -0.91 21.60b 9.92b -12.55b -_-- --- 95.85b 14.39b 0.38 1.04 2.71 2.71 -2.06 115.25b 33.3b 2.64 0.18 0.01 0.81 2.02 0.87 1.25 SANDSAGE 1 2 3 1.008 0.679 0.642 0.417 0.342 0.438 0.523 0.591 0.769 0.872 0.615 0.537 0.828 0.745 0.767 0.925 0.560 0.648 Il,31 £1,3 t - COl-IBINED 1 2 3 0.565 0.407 0.302 0.142 0.130 0.088 0.425 0.476 0.330 0.444 0.369 0.323 0.391 0.335 0.465 0.383 0.393 ·0.411 £1,31 £1,3 t - all,31 represents an analysis of covariance comparing trends among the 17 treatment and 17 control transects ignoring sites. £1,3 is an analysis among sites. t tests at 2 d.f. represent paired tests of year to year differences among sites. bCP<0.05). "'" 0 V1 �406 0.5 0.4 0.3 ••..... .§ ..... )04 ~ {/) 0.2 z til 0 I ~ H til :z: 0.1 o 1985 1986 1987 Fig. 4. Height-density (dm) of grass-forb and combined residual vegetation in early spring pre- (1985) and posttreatment (1986-87) within the 1985 burned and control sites, Tamarack Prairie, Colorado. �Height-density (dm) means within 1986 burns and their controls during early spring 1985-87 Table 5. intervals with statistical values of re1ationships.a . Site 1985 Treatment 1986 1987 1985 Control 1986 1987 1985-87 1986-87 GRASS-FORB 1 2 3 0.326 0.314 0.259 0.304 0.337 0.256 0.120 0.437 0.202 0.294 0.316 0.233 0.277 0.312 0.213 0.234 0.404 0.269 £.1,35 fl.,3 0.885 0.833 0.671 £.1,35 fI,3 t t 3.13 0.27 1.27 5.26b 0.88 1. 78 28.22b 38.96b 3.80 26.42b 51. 22b 4.79b 8.40b 0.91 1.47 8.71b 0.70 1.43 SANDSAGE 1 2 3 0.621 0.375 0.395 0.838 0.500 0.650 0.169 0.250 0.250 0.829 0.417 0.618 0.756 0.300 0.690 - COMBINED 1 2 3 0.421 0.315 0.272 0.470 0.339 0.281 0.127 0.434 0.204 0.345 0.317 0.298 0.342 0.331 0.323 0.325 0.413 0.357 £.1,35 fI,3 t - a1985 and 1986 were both pre-treatment years. !:.l,35represents analysis among the 19 treatment and 19 control transects ignoring sites. !:.I,3is an analysis among sites. t tests at 2 d.f. represent paired tests of year to year differences among sites. bp<0.05. .j:'- 0 "'-l �408 0.4 .••. _hi.r\ed 'leg. COl'''"' ••• _ surn • •• ~ - - __ •.•• ~........ -•••Co~ed -•••••••••••••••••••••••• 0.3 -~ ..... V g e· - ••••• cont. - ------~-------------;;:~~~ Grass-Forb - Burn ---_ Grass-Forb - Control - ~ ~ Ul i5 0.2 Q I !i: ~ H ~ 0.1 o 1985 1986 1987 Fig. 5. Height-density (dm) of grass-forb and combined residual vegetation in early spring pre- (1985-86) and post-treatment (1987) intervals within the 1986 burned and control sites, Tamarack Prairie, Colorado. �409 It is evident that grass-forb vegetation within the 1985 burns recovered faster and to a greater extent after fire than that within the 1984 burns. In addition, the HDI of grass-forb cover was not reduced as much during the first year following the 1986 burns when compared with previous burns. The reasons why are not conclusively evident at this time but several factors are suspect. Precipitation was considered a primary factor influencing vegetation recovery. Rainfall remained below normal from May through August 1984, and although accurate measurements were not obtained, it appeared more deficient in burn 3-84 than in burn 1-84. Precipitation in 1985 remained slightly below average (Fig. 1), especially during the growing season, but strong biases in amounts received among sites were not detected. In 1986, above average precipitation was received but biases in distribution were noted. The eastern and central portions of the Tamarack Prairie received greater amounts than the west portion in April and July (Snyder 1987). Thus, the 1985 and 1986 burns would have received more during the growing season than burn 1-84 where vegetative growth was observably suppressed in 1986. This is believed to be a major factor in the slow recovery of vegetation within burn 1-84. Burn 3-84 in the south-central part of·the Tamarack Prairie, received more rainfall than burn 1-84 in 1986 but a marked recovery in HDI was not noted, possibly due to more sandy soils and grass-forb suppression by sandsage. That grass-forb vegetation did not show as drastic a reduction 1 year following 1986 controlled burning, as previous sites had shown, is additional evidence that increas~d precipitation promoted rapid recovery. Phenologically, the 1984 burns were conducted much earlier than those in 1985 and 1986 (Fig. 2). Sandsage had begun only minor leafing in 1984 when it was burned and it resprouted and grew rapidly. Subsequent phenologically later burns in 1985 and 1986 appeared to severely suppress sandsage and sprouting and regrowth were much slower. Thus, sandsage in 1984 was much more competitive with grass-forb vegetation after the burns, especially in burn 3-84 where it was the dominant species (Table 6). Grasshopper defoliation of grass-forb vegetation was also severe following the fire in burn 3-84. Total annual precipitation was plotted in relation to grass-forb and combined vegetation among controls for the several burns in an attempt to see if a precipitation - HDI relationship existed. No relationship is evident. Snow compaction (lodging) of vegetation over winter is probably of equal or greater influence on the residual cover and resulting HDI. Additional data collection may provide insight into the influences of timing of burns and subsequent precipitation amounts on grass-forb height-density quality.· Until then, the effectiveness of controlled burning as a method for enhancing height-density quality of grass-forb cover in the Tamarack Prairie remains uncertain. Crown Cover, Composition, and Frequency of Occurrence.--The 1984 burns and their controls, which had not been sampled in 1986, were replicated in August 1987 using the metric belt transect system previously used. Sampling was not conducted within the 1985 and 1986 burns on their controls in 1987. Crown cover, composition, and frequency of occurrence for burns 1-84 and 3-84 differed (Tables 7, 8). Mean crown cover through all sampling intervals for the 2 burns and their controls also differed (Table 9). A review of primary species based on these analyses follows. �410 Table 6. Percent total height-density samples obstructed by sandsage at the 1984, 1985, and 1986 burn sites from 1984 through 1987, Tamarack Prairie, Colorado. Year burned 1984 1 3 1985 1 2 3 1986 1984 Treatment 1985 1986 1987 1984 Control 1986 1985 1987 19.4a 44.7a 13.3 26.2 12.7 38.1 15.8 38.3 16.7 46.3 15.9 51.5 12.9 50.8 13.6 44.0 x l1.6a 8.7a 26.3a 13.8a 1.4 4.8 9.1 4.8 5.5 3.4 16.3 7.1 13.9 8.7 42.5 18.6 13.2 11.8 48.6 21.3 10.0 9.1 51.7 20.1 X 32.1 0.9 8.4 15.5 30.9a 1.2a 7.5a 15.2a 13.2 1.3 3.1 6.4 9.6 1.3 17.0 11.0 13.7 3.1 23.3 15.7 13.9 1.9 21.9 14.7 Site 1 2 3 aDenotes burn treatment occurred. Blue Grama (Bouteloua graci1is).--Data within burn 1-84 (Table 9) showed a trend similar to that from the 1985 and 1986 burns (Snyder 1987) indicating that controlled burns potentially enhanced this species. However, from Summer 1984 through 1987 sampling treatment and control transects have shown nearly identical trends. Since blue grama is a short species, and often in partial understory to other vegetation, removal of overs tory residual by fire may have exposed more blue grama to visual contact increasing sampling tallies during the first growing season. Blue grama within burn 3-84 comprised a much smaller percentage of the total composition, which combined with a small number of transects, provides less confidence in findings which conflict with those during first-year intervals within other burns. Needle-and-Thread (Stipas Comata).--Findings from both burn 1-84 and 3-84 show trends similar to data obtained from the 1985 and 1986 burns (Snyder 1987) indicating this species was set back during the first growing season after fire. The first-year set back is understandable as this cool-season species had made growth to 15.2 cm in 1984 when burned, and to 35-40 cm (was beginning to head) in 1985 when burned. In 1986 needle-and-thread height was 15-25 cm when burned. Within all burned sites the species made a dramatic recovery during the 2nd growing season including greatly enhanced seed production. Changes from 1985 to 1987 within burn 1-84 were similar between burned and control transects, whereas within burn 3-84, control transect means increased over those in the burn (!<0.05, Table 9). No conclusions can be derived from these conflicting findings. Prairie Sanddropseed (Sporobolus cryptandris).--Transect data within burns 1-84 and 3-84 showed conflicting first-year trends (Table 9). These and other conflicting data leave uncertainty as to potential fire impacts on this species. Following additional sampling, a more detailed evaluation will be attempted. �411 Table 7. Crown cover (0.01-m2), species composition (%), and frequency of occurrence of vegetation within treatment and control transects on Tamarack Prairie burn 1-84 during August 1987. Treatment Vegetation Bare ground Dead vegetation Boute1oua gracilis Stipa comata Sporobo1us cryptandrus Ca1amovi1fa longifo1ia Andropogon ha11ii Agropyron smithii Aristida sp. Paspa1um stramineum Muh1enbergia sp. Ko1eria cristata Panicum virga tum Festuca octof1ora Cyperus & Carex spp. Artemisia fi1ifo1ia Opuntia sp. Mammi1aria & Echinocereus Ambrosia psi10stachya Artemisia 1udoviciana Tradescantia occidenta1is Phlox andico1a Evo1vu1us nutta1ianus Lathyrus po1ymorphus Penstomen angustifo1uis The1esperma megapotimicum Liatris punctata Mentze1ia nuda Lygodesmia juncea Psora1ea tenuif10ra Physalis subg1abrata Erigeron sp. Astragalus sp. Chenopodium album Plantago purshii Eriogonum annum Pepidium densif10rum Cryptantha sp. Croton texensis Euphorbia sp. Conyza canadensis He1ianthus sp. Crown cover Compo Control Freq.! occur. 1,217.0 1,873.0 726.5 598.5 248.0 485.5 149.5 2.0 2.0 26.32 21.69 8.99 17.59 5.42 0.07 0.07 97.78 100.00 95.56 95.56 55.56 6.67 4.44 1.0 3.0 56.0 -20.0 359.0 9.0 0.04 0.11 2.03 0.73 13.01 0.33 4.44 2.22 62.22 13.33 80.00 22.22 2.0 0.07 4.44 40.0 4.0 8.0 10.5 1.45 0.15 0.29 0.38 40.00 11.11 17.77 11.11 4.0 0.15 11.11 1.5 0.5 1.5 0.05 0.02 0.05 2.22 2.22 6.67 1.5 7.0 0.5 1.5 1.0 2.5 13.0 1.0 0.05 0.25 0.02 0.05 0.04 0.09 0.47 0.04 6.67 24.44 2.22 4.44 4.44 13.33 13.33 2.22 Crown cover Compo Freq.! occur. 929.0 2,236.0 638.0 707.5 163.5 578.5 117.5 7.5 5.0 6.0 23.76 26.35 6.09 21.55 4.38 0.28 0.19 0.22 100.00 100.00 91.11 100.00 48.89 8.89 4.44 4.44 49.5 18.0 150.0 12.5 0.5 19.5 10.5 76.0 5.5 6.0 1.84 0.67 5.59 0.47 0.02 0.73 0.39 2.83 0.21 0.22 33.33 28.89 77 .80 28.89 2.22 17.78 6.67 55.56 8.89 8.89 4.0 17.0 0.5 1.0 1.0 4.0 0.15 0.63 0.02 0.04 0.04 0.15 8.89 20.00 2.22 2.22 2.22 4.44 9.5 0.5 1.5 4.0 10.0 0.35 0.02 0.06 0.15 0.37 13.33 2.22 6.67 11.11 11.11 1.5 20.0 10.5 28.0 0.5 0.06 0.75 0.39 1.04 0.02 6.67 31.11 8.89 28.89 2.22 �412 Table 8. Crown cover (0.01-m2), species composition (%), and frequency of occurrence of vegetation within treatment and control transects on Tamarack Prairie burn 3-84 during August 1987. Treatment Vegetation Bare ground Dead vegetation Boute1ua gracilis StiEa comata Sporobo1us crYEtandrus Ca1amovi1fa longifo1ia Andropogon ha11ii Agropyron smithii Panicum virgatum Paspa1um stramineum Muh1enbergia sp. Ko1eria cristata Festuca octof1ora Cyperus & Carex spp. Artemisia fi1ifo1ia 0Euntia sp. Mammi1aria & Echinocereus Ambrosia psi10stachya Artemisia 1udoviciana Tradescantia occidenta1is Phlox andico1a Evo1vu1us nutta1ianus Lathyrus po1ymorphus Penstomen angustifo1uis The1esperma megaEotimicum HaE10pappus spinu10sus Mentze1ia nuda Asclepias sp. Erigeron sp. IEomoea 1eptoEhy11a Argemone intermedia Cirsium sp. Physalis subg1abrata Chenpodium album Plantago purshii Croton texensis Euphorbia sp. CrYEtantha sp. Conyza canadensis Amaranthus sp. Crown cover Compo Control Freq.! occur. 748.0 572.0 140.0 175.0 160.0 192.0 31.5 7.0 ·9.5 30.0 0.5 1.0 6.0 16.0 320.5 15.5 0.5 0.5 2.5 19.5 4.0 16.0 10.5 10.94 13.67 12.50 15.00 2.46 0.55 0.74 2.34 0.04 0.08 0.47 1.25 25.04 1.21 0.04 0.04 0.20 1.52 0.31 1.25 0.82 0.90 1.00 1.00 1.00 0.45 0.20 0.20 0.50 0.05 0.05 0.30 0.65 0.95 0.40 0.05 0.05 0.05 0.40 0.25 0.40 0.10 0.5 1.0 7.0 3.5 21.5 21.0 0.04 0.08 0.55 0.27 1.68 1.64 0.05 0.05 0.15 0.10 0.60 0.20 0.5 2.0 3.0 12.5 38.0 2.0 0.04 0.16 0.23 0.98 2.97 0.16 0.05 0.15 0.20 0.35 0.80 0.15 9.5 0.74 0.15 Crown cover ComE· Freq.! occur. 552.5 665.5 128.5 286.5 227.0 131.5 37.0 0.5 5.5 15.5 4.0 9.30 20.73 16.43 9.52 2.68 0.04 0.40 1.12 0.29 0.75 1.00 1.00 0.90 0.45 0.05 0.05 0.50 0.15 24.0 401. 5 16.5 1.74 29.05 1.19 0~85 1.00 0.30 2.5 17.5 0.18 1.27 0.10 0.45 4.0 7.0 1.0 0.29 0.51 0.07 0.15 0.15 0.05 15.0 1.09 0.30 19.0 11.0 0.5 1.0 1.37 0.80 0.04 0.07 0.50 0.05 0.05 0.05 1.5 3.5 11.5 8.5 0.11 0.25 0.83 0.62 0.05 0.30 0.35 0.30 0.5 0.04 0.05 �Mean crown cover (0.01-m2) and analysis of covariance Table 9. samples during pre-treatment (1984) alld post-treatment (1984-87) Vegetation Pre-tr 1984 Burned transects Jul Aug 1984 1985 Aug 1987 relationships for selected species, species groups, and covers within burn and control intervals, burn 1-84 and burn 3-84, Tamarack Prairie, Colorado. Pre-tr 1984 Control transects Aug Jul 1984 1985 F-value Pre treatment 1984 to Aug 84 Aug 87 AUIl 84 . Ju1 85 to 85 Aug 84 to 87 1985 to 87 136.3 151. 2 34.9 123.6 25.1 150.0 32.1 33.0 16.2 198.5 477.8 21. 6a 38.7s 3.6 0.3 1.5 1.1 17.3a 8.1a 9.8a 132.7a 211. o- 14.89a 19.26a 9.82a 5.72a 1. 54 3.16 0.0 0.11 17.22a 166.6a 87.05a 61.8 1)7.7 109.2 63.2 17.8 91.1 193.0 37.3 12.7 265.6 320.0 2.3 6.8a 0.4 0.3 0.1 0.4 23.9a 2.6 0.7 280.2a 90.0 0.43 0.95 0.71 4.15 0.40 3.18 0.07 0.24 18.00a 94.49a 31. 81 Aug 1987 BURN 1-84 Bouteloua Ilraci1is Stipa ~ Sporobo1us sp. Calamovilfa sp , Andropollon hal1ii Comb. warm season Artemisia fl1ifo1ia Perennial forbs Annual forbs Bare ground Dead vegetation 362.4 257.7 44.9 185.7 28.7 213.7 102.9 16.3 3.1 117.3 124.8 310.2 86.5 75.4 197.3 47.7 245.8 75.8 40.8 4.1 386.6 7.5 116.5 103.3 58.5 73.3 16.5 89.9 84.0 12.5 15.9 458.5 301. 9 155.2 127.9 53.0 103.7 31.9 136.3 76.7 15.4 6.0 260.1 400.2 510.3 187.0 34.4 194.8 21.8 216.9 63.5 27.6 1.6 104.4 91.7 325.1 183.2 36.9 191. 5 29.2 221. 7 67.2 28.8 50.6 91.3 233.9 92.6 125.7 18.4 95.6 9.7 105.8 49.5 15.9 2.4 231. 4 6Q1.4 16.42a 22.36a 2.50 1. 32 0.02 0.64 1.30 2.01 4.04 10.75a 11.16a 4.24 3.37 15.56a 7.ns 0.02 5.55a 14.lOa 5.99a 7.92a 0.82 1.54 2.72 5.17~ 0.16 2.56 1.95 2.08 13.00a 10.19a 2.33 4.37 0.37 0.03 0.05 1. 09 0.43 0.74 0.94 3.75 6.36° 5.928 6.86° 11.18a 1.39 2.42 9.00a 3.72 0.49 4.43 0.23 0.03 2.23 4.99 1.05 3.23 1.53 0.30 3.55 0.07 1.95 12 .10a 0.02 16.78 1.18 0.00 0.36 0.88 5.79 9.45a 0.32 7.89a 14.04 0.04 2.40 0.39 1.15 3.16 7.08a 10.42a 0.04 0.0 0.08 0.47 0.08 0.46 0.08 0.52 BURN 3-84 Boute10ua Ilraci1is Stipa comata Sporobo1us sp. Calamovilfa sp , Andropogon hallii Comb. warm season Artemisia fi1ifolia Perennial forbs Annual forbs Bare ground Dead vegetation ap ~ 0.05. bTncludes Ca1amovi1fa 166.4 132.7 110.0 97.6 17.7 128.0 242.4 102.1 2.6 202.9 121. 6 87.5 23.7 69.4 68.2 9.'1 89.4 116.6 85.5 14.3 706.2 31. 4 longifo1ia, 35.1 59.4 53.1 86.1 4.6 95.0 196.4 50.2 63.0 520.2 153.1 Andropogon 67.3 84.1 76.9 92.3 15.2 126.4 154.1 52.0 32.3 359.6 275.0 ha11ii, 1)1.2 169.9 130.4 120.7 15.6 155.7 224.4 61.4 1.6 201. 2 141. 9 93.6 87.1 71.0 72.0 9.4 90.6 293.4 43.4 9.9 189.2 337.0 Panicum virgatum, 25.7' 51. 7 41.8 61.8 5.5 70.0 250.3 27.1 17.8 273.8 460.8 snd Paspalum stramineum. .pI-' lJJ �414 Prairie Sandreed (Calamovilfa longifolia).--Controlled burns in 1984 occurred ahead of greenup of this species and no major stimulus by fire was noted (Table 9). Enhancement of sandreed within 1984 burns was not noted in subsequent years. These findings conflict with results from the 1985 and 1986 burns where later burns and improved post-burn rainfall potentially stimulated increased growth within burned sites (Snyder 1987). Although this species does not stand well over winter, its abundance and quality is a major determinant of the height-density quality of grass-forb vegetation within the Tamarack Prairie. Sand Bluestem (Andropogon hallii).--This less abundant species appeared to be enhanced by fire within burn 1-84 during the first growing season and increased seed head production was noted. However, no evidence of enhancement beyond the first year was noted in burn 1-84 and no evidence of any enhancement from fire was noted within burn 3-84. Burn 1-84 findings were supported by data from the 1985 and 1986 burns (Snyder 1987). Sandsage.--Fire, by removing the growth of preceding y~ars reduced the crown cover especially after the first growing season. Within the 1984 burns rapid regrowth was noted for the first 2 years following fire but by the end of the 4th growing season (1987), crown cover on both sites was less than in July 1985 (Table 9). Crown cover within control transects on both 1984 burn sites continued to decrease from August 1984. General observations support these data indicating sandsage within t~is range possibly cannot compete favorably with ungrazed grasses and is gradually deteriorating. More years of data are needed to substantiate this finding. Review of height-density indices could not discern evidence of deterioration within controls. However, HD1 samples were obtained when the plants were dormant and would not detect deterioration rapidly since most dead branches remain standing for several years. General observations indicate that fires conducted when sandsage is dormant or just beginning to leaf out may stimulate new growth, whereas later spring burns stress but seldom kill the species. Additional data indicate still later burning of sandsage can inflict greater stress and some mortality. As reported earlier (Snyder 1987) 2 fires burned north from Interstate 1-76 on 5 July 1986. Late August 1986 sampling of sandsage survival at 2 locations showed only 14 of 50 plants (28%) resprouted at the upper site and 42 of 50 (84%) resprouted at the lower site. These sandsage plants were resampled on 19 May 1987. On the upper site, 30 of 50 (60%) showed new growth and 86% of the lower 50 were alive. This indicates mid-summer burning can induce mortality and those surviving are extremely stressed and slow to recover. However, burns at that time of year also severely stress many grass species~ Perennial Forbs.--Although perennial forbs seemed to be enhanced during the first growing season after fire within burn 1-84, burn 3-84 data did not support this conclusion. Perennial forbs declined more within burn transects than within controls during the 1985-87 growing seasons. Frequency of occurrence comparisons show no marked declines of perennials either by species or by occurrence within the 1984 sites. More detailed analysis and evaluation is needed. Annual Forbs.--Annual forbs have been highly variable as to species and occurrence within the 1984 burns and their controls during the 3-intervals of �415 post-burn sampling. Pre-treatment 1984 sampling was not considered highly accurate due to over-winter deterioration of most annuals. Fires in 1984 apparently reduced or eliminated some species such as lambsquarter (Chenopodium album) but no marked changes over several growing seasons have been noted. Precipitation patterns and amounts along with temperatures are considered primary factors in establishment of annuals within the Tamarack Prairie. Canada horseweed (Conyza canadensis) was a typical example. Climatic conditions in spring 1987 apparently were involved in its dramatically increased occurrence throughout unburned sections of the Prairie. Bare Ground and Dead Vegetation.--The amount of dead vegetation and/or litter made considerable recovery from 1985 through 1987 within both 1984 burn sites along with marked declines in the amount of bare ground. These trends would be expected. However, it should be noted that complete recovery to pre-treatment levels has not been attained within either burn site. Revegetation Treatments Ti1lage~Reseeding.--The 19 revegetation strips established in 1985 continued to improve in quality. The average HDI in early spring 1987 among 12 random transects was 1.83 dm (range 0.98 to 3.07) with the lowest sample averaging twice the HDI of unmanaged vegetation on the Tamarack Prairie. Four of the transects had been previously sampled in late September 1986 when they yielded a mean HDI of 2.60 dm whereas 4 randomly selected nearby transects domi~ated· by need1e-and-thread and prairie sandreed averaged 1.04 dm. By spring the HDI o~ revegetation transects dominated by switchgrass had declined 19% to 2.11 dm whereas the HDI of native prairie transects had declined 65.7% to 0.36 dm. This illustrates the observably greater over-winter residual value of switchgrass compared to most other grasses native to the Tamarack Prairie. A comparison of crown cover changes within the revegetation strips from 1985 through 1987 revealed differences (Table 10) and illustrates the marked increase in crown cover of switchgrass and b1uestems (p <0.05). Switchgrass and bluestems comprised 77.2% of the composition of revegetation samples in 1987. It is anticipated that as switchgrass crown cover continues to increase within the revegetation strips in future years, grass height will decrease resulting in a gradual decrease in HDI. However, use of fire, and if necessary, tillage, should help sustain the HDI of these revegetation strips at levels much greater than surrounding vegetation. Annual precipitation was above average in 1986 and 1987 promoting excellent growth, whereas the impact of drought remains unknown. Tillage Renovation of Interseeded Tracts.--Efforts to evaluate vegetation changes within a tract that previously had been interseeded (1981-82) and partially renovated (disced, harrowed, treated with atrazine herbicide) in spring 1986 (Snyder 1987) continued in 1987. A portion of this tract had been included within the 1-84 burn and pre- and post-treatment crown cover sampling had indicated interseeded switchgrass and b1uestems responded more favorably than other grasses to fire (l <0.05, Snyder 1986). Subsequent evaluation of the tillage-herbicide renovation was not biased by the previous burn because the burned and unburned portions and their respective crown cover transects were bisected by the renovation and control tracts in spring 1986. �416 Table 10. Crown cover among 1985-87 sampling intervals from 12 random transects within the 1985 revegetation strips, Tamarack Prairie, Colorado. Vegetation or cover Bare ground Dead vegetation 1985 Subtotal N 804 212 1986 Subtotal N 812 156 1,016 Bouteloua gracilis Stipa comata Ca1amovilfa longifo1ia Sporobo1us cryptandrus 25 968 4 17 5 5 2 5 1 475 o o o o o o o o 3 5 1 6 1 1 1 8 10 1 1 2 8 3 833 5 3 7 1 21 61 772 3 2 22 Croton texensis Conzya canadensis Other annuals 2 37 6 Psoralea tenuiflora Sphaeralcea coccinea Physalis subglabrata Ipomoea leptophylla Oenothera sp. Cichorium intybus Evo1vu1us notta1ianus Liatris sp. Mentze1ia nuda o 75 400 8 303 183 17 10 311 Artemisia filifo1ia Opuntia sp. 45 99 226 79 Andropogon sp. Panicum virgatum o 57 128 64 11 650 39 1 217 Agropyron smithii Panicum capillare Cyperus & Carex Paspalum stramineum 278 372 40 66 126 1987 Subtotal N 12 76 2 5 18 76 o 8 31 �417 Pre-treatment and first-year post-treatment HDI varied (Table 11). Grass-forb HDI declined from spring 1986 to 1987 on both the tillage-herbicide and control sites, possibly because of deficient localized rainfall during the 1986 growing season. The tillage-herbicide treatment completely removed all standing residual in early spring 1986 so the recovery through the 1986 growing season would have to be dramatic to equal the HDI on the control by the following spring. Sandsage was more severely impacted by tillage (Table 11) and subsequently also influenced comparisons of combined vegetation. Table 11. Height-density (dm) means of grass-forb, sandsage, and combined cover from pre-treatment (1986) to post-treatment (1987) intervals between a tillage-herbicide and untreated control within a previously interseeded location, Tamarack Prairie, Colorado. Year Tillage-herbicide Control Grass-Forb 1986 1987 0.382 0.314 0.393 0.271 Sandsage 1986 1987 1.234 0.227 0.696 0.608 Combined 1986 1987 0.579 0.306 0.544 0.375 Crown cover sampling in August 1987 revealed that interseeded bluestems and switchgrass increased at a greater rate within the renovated transects than within controls from 1986 to 1987 (p <0.10, Table 12). Averages were much greater than those obtained during the 1985 pre-treatment sampling showing that the interseeded grasses were markedly enhanced by tillage-herbicide renovation. In contrast, sandreed, another deep-rooted native showed only modest increase from 1985 to 1987 (Table 12). Other native grasses with more shallow root systems were reduced by the treatment and showed little recovery from 1986 to 1987. The occupancy by perennial forbs was little affected by the tillage-herbicide treatment. �418 Table 12. Average crown cover/transect of selected species and species groups from pre-treatment (1985) to post-treatment (1986-87) intervals within tillage-herbicide renovation of an inter seeded site and its control, Tamarack Prairie, Colorado. Species/sEecies group Andropogon - Panicum Calimovilfa longifolia Bouteloua, Stipa, Sporobolus, etc. Perennial forbs Tillage-herbicide 1985 1986 1987 1985 Control 1986 1987 13.7 11.3 17.6 24.2 12.4 5.4 36.3 13.8 6.4 16.4 10.7 17.1 16.6 10.6 16.8 22.1 10.2 19.8 1.5 0.6 1.2 2.2 1.7 3.4 85-86 F Values 85-87 86-87 34.68a 61.94a 1.04 2.76 62.11a 66.70a 1.76 2.92 3.62b 1.78 2.87 1.56 ap < 0.05. bp<O.lO. Early spring 1987 height density sampling was conducted on 4 randomly selected tracts of the 30 renovated interseeded tracts treated in spring 1986 •. Their HDI's averaged 0.23, 0.26, 0.42, and 0.73. The highest index was obtained on the most easterly tract that had received greater precipitation during the 1986 growing season. Bluestem seed was harvested in fall 1987 from that tract leaving a tall stubble. Observations indicated all renovation tracts made considerable additional recovery during the 1987 growing season that potentially will be revealed in 1988 HDI sampling. Management personnel used tillage-herbicide renovation on 4 additional interseeded tracts within the northeastern part of the Tamarack Prairie in April 1987. Two large tracts adjacent to the property boundary were reseeded and subsequent rains promoted dense switchgrass stands while diluting the atrazine allowing dense stands of annual forbs to establish. One tract was mowed by management personnel in early summer to curtail weed growth. Strip Spraying of Sandsage Pre-treatment (May 1985) sampling of crown cover was completed within the large tract sprayed in June 1985 with herbicide to partially kill sandsage, however, pre-treatment HDI sampling was not conducted. Height-density sampling on 2 of the transects was conducted in early spring 1986 and on 11 transects in 1987. No marked HDI change had occurred within the 2 transects from 1986 to 1987 and sandsage, while dead, remained standing to contribute considerably to the visual obstruction during early spring intervals (Table 13). A smaller tract within the spray site was burned in spring 1986 and 4 transects were sampled for HDI during pre-burn (1986) and 1987 early-spring intervals. Analysis indicated major reduction of grass, sandsage, and combined vegetation following the treatment (_!: < 0.05, Table 13). �Table 13. Height-density (dm) means within the 1985 sandsage spray site during 1986 and 1987 post-spray intervals and pre-burn (1986) to post-burn (1987) intervals within a portion of the spray site burned in 1986, Tamarack Prairie, Colorado. Year Transects Grass-forb Sandsage Combined vegetation 1985 SANDSAGE SPRAY 1986 1987 0.-246 0.272 2 11 0.879 0.800 0.468 0.469 1985 SANDSAGE SPRAY - 1986 BURN 1986 1987 0.279 0.122 4 4 t 4.9 with 3 df 0.713 0_.333 0.404 0.129 t = 8.68 with 3 df Crown cover sampling within the sandsage spray site from May 1985 (pre-treatment) through 1986 and 1987 intervals revealed differences (Table 14). All major grasses except sandreed have shown crown cover increases following herbicide treatment. Live sandsage was almost totally eliminated although the attempt was for a partial reduction through strip spraying (Snyder 1986b). Perennial forbs were nearly eliminated in summer 1985 following the herbicide treatment. However, by spring 1986 considerable recovery was noted and this recovery continued into 1987 (Table 14). Perennial sweet pea (Lathyrus po1ymorphus) has been the primary species to recover and has dominated all sampling intervals. The number of species counted remained much reduced from pre-treatment sampling (Table 14). �420 Table 14. Crown cover (point frame) of vegetation and ground cover within 11 random transects during pre- (1985) and post-treatment (1986-87) May intervals within the June 1985 herbicide treated sandsage spray tract, Tamarack Prairie, Colorado. Vegetation/cover Bare ground Dead vegetation Perennial grass Boute1oua gracilis Stipa comata Sporobo1us cryptandrus Ca1amovilfa longifolia Andropogon ha11ii Muhlenbergia pungens Ko1eria cristata Aristida sp. Agropyron smithii Carex sp. Annual grass Bromus tectorum Festuca sp. Pre-treatment 1985 Post-treatment 1987 1986 402 1,425 529 1,324 536 1,083 142 194 34 51 148 510 46 65 2 3 9 1 312 425 106 53 2 3 6 3 1 3 5 70 117 4 116 7 Artemisia fi1ifo1ia (alive) A. fi1ifo1ia (dead) 436 112 1 259 287 Opuntia & Echinocereus spp. 44 50 62 5 18 114 55 4 1 9 77 Perennia forbs Ambrosia & Artemisia spp. Tradescantia occidentalis Lathyrus polymorphus Psoralea tenuif10ra Phlox andico1a Evo1vu1us nutta1ianus Abronia fragrans Cymopteris montanus Allium textile Mentzelia nuda Leucocrinum montanum Penstemon angustifo1ius The1esperma megapotimicum Annual forbs Croton texensis Chenopodium album Pepidium & Lesquerella sp. Cryptanthia sp. Tragopogan sp. Plantag purshii Salsola kali Unid. forbs 6 2 2 ° 22 123 1 6 1 1 6 1 1 1 4 1 12 1 2 2 3 24 3 2 1 2 1 1 1 �421 LITERATURE CITED Snyder, W. D. 1986a. Sandsage-bluestem prairie renovation. Job Progress Rep., Colorado Div. Wildl. Wildl. Res. Rep., Fed. Aid Proj. 01-03-045 (W-37-R). Apr.:475-498. 1986b. Sandsage-bluestem pralrle renovation. Job Progress Rep., Colorado Div. Wildl. Wildl. Res. Rep., Fed. Aid Proj. 01-03-045 (W-37-R). Apr.:499-525. 1987. Sandsage-bluestem prairie renovation. Job Progress Rep., Colorado Div. Wildl. Wildl. Res. Rep., Fed. Aid Proj. W-152-R. In Press. Prepared by W~ Warren D. Snyder Wildlife Researcher C JyM ��423 JOB PROGRESS REPORT Co'Lo'rado State of: Project: W-152-R Avian Research 21 Job Title: Response of Selected Wildlife Species to Aspen Silvicultural Practices Period Covered: Author: Job 4 --- Work Plan: 01 January through 31 December 1987 Suzanne M. Joy Personnel: C. E. Braun and R. W. Hoffman, Colorado Division of Wildlife (CDOW); R. T. Reynolds, u.S. Forest Service (USFS); R. L. Knight and S. M. Joy, Colorado State University (CSU) ABSTRACT In August 1987, the CDOW, USFS, and CSU entered into a cooperative study to investigate nest site characteristics and foraging behavior of sharp-shinned hawks (Accipiter striatus) and other accipiter hawks fn mature aspen and conifer habitats. A literature review was initiated in preparation for writing a study plan. A study plan was prepared, peer reviewed, and approved by the cooperating agencies. The study plan is presented as part of this report. ��425 RESPONSES OF SELECTED WILDLIFE SPECIES TO ASPEN SILVICULTURAL PRACTICES Suzanne M. Joy P. N. OBJECTIVES 1. Examine and evaluate existing literature on aspen-wildlife relationships to identify information needs pertinent to the development of a detailed study plan. 2. Interview selected personnel of the CDOW, USFS, BLM, and Louisiana Pacific Corporation concerning research needs within the aspen type. 3. Prioritize research needs and identify funding sources. 4. Prepare a detailed study plan on an approved research topic dealing with aspen-wildlife relationships. SEGMENT OBJECTIVES 1. Review literature on aspen ecology, aspen silvicultural practices, aspen-wildlife relationships, effe~ts of aspen manipulation on wildlife populations, and chemical and nutritional characteristics of aspen. 2. Prepare a detailed study plan on an approved research topic. 3. Prepare annual progress report. ��427 PROGRAM NARRATIVE (Research) State: Colorado Project Title: Study Title: Project Number: Avian Research Work Plan: W-152-R 21 Job: 4 Accipiter Nest Site Selection and Foraging Behavior of Sharp-shinned Hawks in Mature Aspen and Conifer Habitats A. NEED: Quaking aspen (Populus tremuloides) dominated forests are widely distributed throughout the Central Rocky Mountains. Pure aspen and mixed conifer-aspen stands are extensive and provide nesting and foraging habitat for numerous avian species. that occur in aspen forest types. DeByle (1985) listd 135 bird species In Colorado, the largest pure stands of aspen are on the western slope, where they often occur in close association with Engelmann spruce (Picea engelmannii)-fir (Abies spp.) forests (Flack 1976, Johnston and Hendzel 1985, Mueggler 1985). Aspen stands in Colorado comprise over 60% (1.15 of 1.78 million ha) of the commercial aspen area (i.e., trees suitable for industrial wood products) in the western United States and over 25% (1.15 of 4.58 million ha) of Colorado's commercial timberland (Green and Van Hooser 1983). Aspen is harvested for a variety of wood products including pulp, paper, particle board, f1akeboard, and matches (Wengert et ale 1985). Little is known about habitat requirements of avian species in aspen. Scott et ale (1980) listed 18 species of both primary and secondary cavity-nesting birds that nested in aspen trees. Crouch (1983:1), found that removal of mature aspen overstory "adversely affected cavity-nesters and other species requiring mature forest". He also �428 suggested that clearcutting "should benefit (wildlife) species needing sparsely vegetated areas and forest edges". Presently, over 70% (1,484 of 2,004 stands surveyed) of aspen stands in Colorado are in mature (70-120 years) and overmature (120+ years) age classes (W. Shepperd, pers. commun.). Management practices, such as clearcutting and removal of invading conifers, have been prescribed to encourage sucker regeneration and growth of younger stands (Jones et al. 1985). Before the effects of regenerative harvests on aspen avifauna can be fully evaluated, pre-harvest data on bird species and their habitat associations in aspen must be collected. Flack (1976) suggested that abundance of avian species in aspen is regulated by features of the vegetation and that, although some species use apsen habitat opportunistically, for others aspen may be critical. Salt (1957) illustrated the value of aspen when he found 3 times the bird biomass in aspen compared to 5 other vegetation types inventoried. North American accipiters exist sympatrically throughout much of the western United States (Reynolds et al. 1982, Moore and Renny 1983, Fischer and Murphy 1987). atricapillus), The northern goshawk (Accipiter gentilis Cooper's hawk (A. coperii), and sharp-shinned hawk (A. striatus) coexist during the nesting season by exploiting different habitats for nesting (Reynolds et al. 1982, Moore and Renny 1983) and by foraging for birds and mammals of different sizes and taxa (Storer 1966, Reynolds and Meslow 1984). Accipiter nest-site characteristics have been quantified in conifer-dominated forests (Reynolds et al. 1982, Moore and Renny 1983). Fischer and Murphy (1987) provided some nesting data on accipiters in predominantly deciduous forests, but they compared the relative use of 6 �429 habitat types (including aspen) available to the species. To date, no studies have focused on nesting habitat of accipiters exclusively using aspen forests. Proposed aspen management by clearcutting and removal of invading conifers emphasizes the need for these data. Habitats used for foraging by accipiters must contain a sufficient number of available prey, vegetative cover for protection and concealment while hunting, and trees of suitable densities and sizes to permit uninhibited flight. Accipiters forage in structurally diverse habitats, with considerable interspecific and intersexual variation in preference (Fischer and Murphy 1987). forests opportunistically Because accipiters appear to use available (given that they are sufficiently open to allow flight), Reynolds (1988) suggested that differences in habitats used for foraging are more closely linked to prey availability than tree species composition or habitat structure. Alterations in habitat structure and/or composition affect bird and mammal populations, which may in turn affect the reproductive performance and abundance of one or more accipiter (Reynolds 1988). Few data exist on use of space in aspen forest types by foraging accipiters. Therefore, to better predict the effects of aspen harvest, analysis of accipiter foraging behavior relative to prey availability in this forest type is needed. Distribution The latitudinal range of North American accipiters includes Alaska and the Northwest Territories, Canada south to Costa Rica, with interspecific variations in breadth and seasonality of distribution. Sharp-shinned hawks are the most migratory accipiter, breeding as far north as the Arctic Circle and wintering north of the equator (Guatemala and Costa Rica) (Mueller and Berger 1967a). Cooper's hawks occur �430 throughout temperate zones of North America, breeding from southern Canada south to the Gulf of Mexico and into Columbia, South America (Brown and Amadon 1968, Wattel 1973); winter range includes Costa Rica north to New England and British Columbia (Bull and Farrand 1983). northern goshawk is circumboreal. The In the nearctic, goshawks occur throughout much of Canada and Alaska south to New England, Maryland, Michigan, New Mexico, Arizona, and northern Mexico (Mueller and Berger 1967£, Brown and Amadon 1968, Wattel 1973, Scott 1987). Accipiters are classified as uncommon residents of Colorado (Bailey and Niedrach 1965:193, 199, 203) and references on their distribution are few. Sightings occur predominantly in western and northern areas of the state (Bailey and Niedrach 1965, Shuster 1976). Seasonal Activities and Movements Sharp-shinned hawks migrate from breeding to wintering ranges presumably in response to prey availability (Newton 1979). The exact timing varies annually, but appears to be initiated by southward movements in their avian prey (Clarke 1984). Sharp-shinned hawks in Colorado begin migration during late August and early September (R. Reynolds, pers. commun.). Mueller and Berger (1967~) reported that immatures migrate approximately 1 month before adults, supposedly to reduce competition with adults for declining prey resources. Goshawks are the least migratory of North American accipiters; migrations occur primarily in response to declining prey populations (Mueller and Berger 1967b). Little information exists on timing of migration by Cooper's hawks; however, Brown and Amadon (1968) noted they are often seen migrating with other hawks. �431 Northward migration for all accipiters begins in early spring. pairs reach breeding sites by March or April. Most Sharp-shinned hawks at high elevations may not arrive at nests until late May (Reynolds 1988). Onset of reproductive behavior is signaled by courtship flights in all 3 species (Bent 1937, Brown and Amadon 1968). Aerial displays and occasional calling serve to attract the female or male (Bent 1937, Brown and Amadon 1968). In all species, one or both sexes construct the nest. When both sexes participate, Brown and Amadon (1968) reported male Cooper's hawks contributed most to the nest, whereas Clarke (1984) found that female sharp-shinned hawks provided the majority of nest material. Sharp-shinned hawks commonly return to the same nest site each year, but build new nests (Bent 1937, Reynolds 1983). Goshawks show high nest fidelity, occupying the same nest for several years (Brown and Amadon 1968, Reynolds 1983). Cooper's hawks return annually to nest in the same section of forest, but generally build nests on new sites (Brown and Amadon 1968). All species are determinate layers. Eggs are primarily incubated by the female and the male delivers prey to her (Brown and Amadon 1968). Prey items are exchanged and plucked at distinct "plucking posts". Sharp-shinned hawks have the shortest incubation period (30-34 days), followed by Cooper's hawks (35-36 days) and goshawks (35-38 days) (Newton 1979). However, Reynolds and Wight (1978) found no difference among incubation periods of accipiters in Oregon (30-32 days). Fledging of sharp-shinned hawks occurs 21-27 days post-hatch, compared to 27-34 days for Cooper's hawks, and 33-43 days for goshawks (Reynolds and lvight (1978, Newton 1979, Clarke 1984). Variations in fledging within a species result from differences in the maturation rate of female and male �432 nest1ings--ma1es are smaller, develop more quickly, and leave the nest earlier than females (Reynolds and Wight 1978, Newton 1979), and uneven growth rates associated with infrequent prey deliveries and poor attentiveness by the female (Newton 1978). Females seldom leave the nest during the nestling period except to defend the brood (Gromme 1935, Fitch et ale 1946, Brown and Amadon 1968, Clarke 1984). Approximately 3 weeks post-hatch, females leave the nest to hunt or perch nearby (Brown and Amadon 1968). Sharp-shinned hawk families separate and individuals disperse from the nest site 3-4 weeks after fledging (Clarke 1984). Platt (1973) noted that dispersal occurred after the flight feathers of young were fully developed. Southward migration begins not long after families disperse. Although post-fledging periods are somewhat longer, the other accipiters exhibit similar behavior. Nest Site Characteristics Nest site is defined as the "area (immediately) surrounding the tree •••used by a nesting pair during an entire nesting season, exclusive of foraging areas" (Reynolds et ale 1982:126). Sharp-shinned hawks tend to nest closer to the ground than their congeners (Moore and Henny 1983, Fischer and Murphy 1987). sharp-shinned Canopy cover at nest sites is high for both (82-98%) and Cooper's hawks (83-95%), whereas, canopy cover is somewhat lower at goshawk nests (68-88%) (Moore and Henny 1983, Fischer and Murphy 1987). Because sharp-shinned and Cooper's hawks typically place nests within the lower portion of the nest tree crown, as opposed to below the canopy as goshawks frequently do (Shuster 1980, Moore and Henny 1983), these percentages may reflect the level of nest concealment each prefers. Topographic features associated with accipiter �433 nest sites include gentle to moderate slopes (0-30%) with northerly (continental United States) or southerly (Alaska) aspects; a source of water occurs either within the nest stand or adjacent to it (Reynolds 1988). Goshawk nests are flat, untidy structures that may exceed 1.5 m diameter (Farley 1923, Brown and Amadon 1968). twigs, small branches, and bark chips. bark and conifer sprigs. Nest materials include The nest bowl is layered with Cooper's hawks nests are built with small twigs and lined with dry deciduous leaves, s~rips of bark, and conifer needles and sprigs (Fitch et ale 1946, Brown and Amadon 1968). Sharp-shinned hawk nests are broad platforms (0.5-m diameter) constructed with freshly cut twigs and lined with flakes of wood or bark (Bent 1937, Clarke 1984). Breeding Success Sharp-shinned hawks lay a mean of 4.4 eggs/clutch (range = 3-6), Cooper's hawks, 4.1 eggs (range = 3-5), and goshawks, 3.2 eggs (range 2-4) (Platt 1976, Reynolds and Wight 1978, Clarke 1984). Hatching success is lowest for sharp-shinned hawks (64.4%), followed by Cooper's hawks (74.0%), and goshawks (81.2%) (Reynolds and Wight 1978). Productivity or nesting success is defined as the number of young fledged per nest attempt. Based on a review of 8 studies, Reynolds (1988) reported that sharp-shinned hawks produce a mean of 3.0 (range = 2-4) fledglings per nest attempt, while Cooper's hawks fledge 2.3 young (range = 2-3), and northern goshawks fledge 1.9 young (range = 1-3). Foraging Behavior, Home Range, and Daily Activity Rhythms Descriptions of accipiter hunting behavior range from "sit and wait" strategies (where the hawks passively wait for prey to pass within range before attacking) to more aggressive "short-stay perched-hunting" �434 strategies (where they actively search their surroundings for potential prey items while perched briefly between flying bouts) (reviewed by Fischer and Murphy 1986). Distance traveled while searching for prey partly determines home range size. Reynolds (1983, 1988) summarized estimates of home ranges for all accipiter species. Nesting sharp-shinned hawks traversed areas of approximately 380, 706, 460, and 100-1,248 ha in Alaska, Ontario, Oregon, and Wyoming, respectively. Cooper's hawks traveled over larger areas during nesting (range = 173 ha in Wyoming to 1,830 ha in New York), while home range estimates for nesting goshawks were even greater (up to 2,463 ha). In a comparative study of daily activity rhythms of accipiters, Fischer and Murphy (1986) found sharp-shinned hawks were most active in the early morning (0500-0900 MDT) and evening (1700-2100). Peak activity of Cooper's hawks occurred during late morning (0900-1300) and remained fairly high throughout the day. A single male goshawk exhibited activity peaks in the late morning (ca. 1100) and late evening (ca. 2000). Equating "activity" with locomotion and, later, foraging, Fischer and Murphy (1986) found that hawk activity patterns corresponded to activity periods in their prey species. Fischer and Murphy (1986) also investigated duration of flights and perching bouts in accipiters. Sharp-shinned hawks exhibited shorter flights (10-20 sec) and perching bouts (2-3 min) than congeners, which ranged from 15-20 sec, and 2-6 min, respectively, for goshawks and Cooper's hawks combined. Nesting and Foraging Habitat in Western Montane Forests Sharp-shinned hawks nest in dense, young, even-aged conifer stands (Hennessy 1978, Reynolds et a1. 1982, Moore and Henny 19~3, Clarke 1984), but occasionally use dense, young stands in deciduous forests (Platt �435 1973, Reynolds et ale 1982, Fischer and Murphy 1987). Nest concealment is important to sharp-shinned hawks because they are ineffective in defending against predators such as owls and others hawks (Reynolds 1988). Nesting sharp-shinned hawks were only found in mature aspen stands when islands of conifers (Picea or Abies spp.) occurred within the stand (Reynolds, pers. commun.). Layered foliage associated with the deep, conical crowns of conifers provide the necessary cover not provided by the narrow, high crowns of mature aspen trees (Reynolds 1988). Consequently, mature aspen stands devoid of conifers are prob~bly unsuitable for nesting sharp-shinned hawks. Small birds (10-30 g) associated with the forest canopy comprise over 95% of sharp-shinned hawks' diet (Craighead and Craighead 1956, Storer 1966, Clarke 1984, Reynolds and Meslow 1984). Flack (1976) demonstrated that aspen canopies in Arizona, New Mexico, Colorado, Utah, California, and Wyoming contained 41.4% (818 of 1,975 individuals) of all breeding birds occurring in the 4 nesting guilds he defined (canopy, shrub, hole, and ground). Birds occurring in the upper-most stratum of mature Colorado aspen forests were more abundant (52.7%; 178 of 338 individuals) than in all other nesting guilds compared. Thus, the upper canopy of mature aspen forests contains ample food for the smaller sharp-shinned hawk, making this forest type ideal foraging habitat. Northern goshawks nest in mature or old-growth coniferous or deciduous forests (Shuster 1980, Reynolds et ale 1982). They require large trees that can support their heavy nests and stands with sufficient space to allow unimpaired flight. Reynolds and Meslow (1984) reported that goshawks take vertebrate prey (x = 307 ± 364 g SD, ~ = 218) from lower portions of the vegetative �436 column. Goshawk foraging success is a function of their ability to detect, pursue and seize prey--a function of the amount of obstructing vegetation and cover available to the prey. Many mature aspen forests in the Rocky Mountains support numerous undergrowth plants (forbs, grasses, and shrubs) (Mueggler 1985) that form a dense, tall (1-3 m) understory that may eliminate foraging by goshawks in this vegetative zone. Cooper's hawks nest in dense stands of young to mature deciduous and coniferous forests (Reynolds et al. 1982, Moore and Henny 1983, Fischer and Murphy 1987). Although Cooper's hawks are less vulnerable to nest predation than sharp-shinned hawks, nest concealment provided by high vegetation density is still an important habitat feature for this species. Cooper's hawks take some prey from the lower vegetative column, bu~ are less restricted to this zone than goshawks (Reynolds and Meslow 1984). Thus, dense understories in mature aspen may limit Cooper's hawks to foraging in the mid-zones in this habitat type. Mature aspen forests appear to provide suitable nesting habitat, but inferior foraging habitat for goshawks, poor nesting and marginal foraging habitat for Cooper's hawks, and poor nesting (when conifers are absent) and good foraging habitat for sharp-shinned hawks. Preliminary field surveys for nests of accipiters (1986-1987) in Colorado (R. Reynolds, pers. commun.) appear to confirm these hypotheses (additional data are needed to support or refute initial observations). Consequently, harvest of aspen (particularly stands that are succeeding to conifers) could reduce sharp-shinned hawk foraging and nesting habitat. Aspen harvests may also reduce the amount of foraging habitat available to other accipiters by decreasing the abundance of conifer or mixed aspen-conifer stands. �437 Research efforts will concentrate on sharp-shinned hawks, because· this species appears to be more abundant and sensitive to apsen cutting, forages closer to its nest, and initiates nesting at a later date than congeners thus allowing post-winter travel conditions to improve on the study area. However, foraging behaviors and nest site characteristics of goshawks and Cooper's hawks will be measured when practical. Study Area Portions of Gunnison, Grand Mesa, and Uncompahgre National forests in Gunnison, Delta, Mesa, Montrose, and Ouray counties, Colorado were selected for study. Climax aspen stands and conifer communities exist in these forests between 2,750 and 3,200 m, allowing comparative studies between mature aspen and conifer habitats. Both large (>500 ha) and small (100-200 ha) stands of mature aspen and mature spruce-fir occur in this area. At lower elevations, the forests are broken by large (100-500 ha) clearings with low shrub, herb, and grass cover. are dominated by Gambel's oak (Quercus gambelii). South-facing slopes Active nests will determine individual study areas within these regions. Morgan (1969) listed several species of plants occurring in aspen understories of Gunnison County. Dominant forbs include meadow rue (Thalictrum fendleri), butterweed groundsel (Senecio serra), Porter lovage (Ligusticum porteri), white geranium (Geranium richardsonii), Barbey larkspur (Delphinium barbevi), sweet cicely (Osmorhiza obtusa), American vetch (Vicia americana), and white-flowered peavine (Lathyrus leucanthus). Prominent low growing plants include elk sedge (Carex geyeri), wild strawberry (Fragaria ovalis), yellow prairie violet (Viola nuttallii), and fringed brome (Bromus ciliatus). The shrub component consists primarily of snowberry (Symphoricarpos spp.) mixed with �438 red-berried elder (Sambucus racemosa) and chokecherry (Prunus virginiana) (R. Reynolds, pers. commun.). In Gunnison, Grand 11esa, and Uncompahgre National forests, Johnston and Hendzel (1985) reported plant associations between Engelmann spruce/elk sedge, Douglas-fir/kinnikinnik Arctostaphylos (Pseudotsuga menziesii/ uvaursi), and subalpine fir (Abies lasiocarpa)/elk sedge where aspen is seral to conifers. Common plant names were obtained from Weber (1976). B. OBJECTIVES AND HYPOTHESES: The objectives of 'the study are to (1) measure sharp-shinned hawk daily activity budgets in mature aspen and conifer overstory types, (2) compare sizes and taxa of prey delivered to sharp-shinned hawk nests in each overs tory type through the breeding season, (3) measure time between prey deliveries to nests in relation to breeding phenology and prey abundance in the 2 overs tory types, and (4) describe nest site characteristics of sharp-shinned hawks, Cooper's hawks, and goshawks found in each overstory type. Null hypotheses to be tested are: Ha: Perch and flight times, and periods of peak activity do not differ between aspen and conifer cover types and/or among incubation, nestling, and fledgling stages of breeding phenology. Hb: Mean time between deliveries, and composition (size and taxon) of prey delivered to nests do not differ between aspen and conifer cover types. Hc: Mean time between deliveries, and composition of food delivered to nests do not differ among incubation, nestling, and early fledgling stages of food provisioning. �439 C. EXPECTED RESULTS AND BENEFITS Knowledge of sharp-shinned hawk foraging behavior and nesting accipiters in mature aspen and conifer forests will allow wildlife managers to better predict effects of logging practices and other perturbations on accipiter population numbers. New guidelines for aspen management practices may be developed based on sharp-shinned hawk foraging efficiency and/or accipiter nest site selection in forest type. In addition, this study may identify factors limiting accipiter distribution in these habitats. Reynolds (1988) called for increased work on foraging habitat of Accipiter spp. to better identify the habitat association of these forest hawks. Data concerning foraging rates and activity budgets of sharp-shinned hawks should contribute to a better understanding of accipiter foraging behavior in different habitats and may stimulate new hypotheses for research. D. APPROACH 1. Review of relevant scientific literature. 2a. Field work will begin in May when sharp-shinned hawks arrive from wintering areas and begin breeding. Aspen and conifer stands containing structural characteristics typical of accipiter nest sites in western montane forests will be searched for active nests. If few or no active nests are located, presumed "unsuitable" stands will be searched. Active nest sites will be distinguished from inactive sites by the presence of a breeding pair, nest, plucking posts with recent prey remains, and/or feces. Active sites will determine individual study areas. 2b. known. Locations of 4 previously occupied sharp-shinned hawk nests are Attempts will be made to locate additional nesting pairs for �440 radiomarking in pure stands of aspen and conifer (target = 4 nests/cover type/year). Nests" in designated forest cover types ~2 km from another cover type will be used for radiomarking since foraging sharp-shinned hawks generally do not travel >1.5 km from the nest (Reynolds 1983). Visual observations (% per cover type) will be used to confirm that radiomarked hawks are foraging predominantly (~90%) in the designated cover type. 3. The following nest site variables will be measured: 1) elevation (topographic map), 2) slope (clinometer), 3) aspect at the nest tree (compass), 4) nest height (clinometer) and directional exposure (compass), 5) nest tree species, height (clinometer), diameter breast height (dbh) (metric tape), and crown depth (clinometer), 6) canopy cover at the nest in the 4 cardinal compass directions (densiometer), 7) distance of nest tree to water and nearest other cover type (metric tape), 8) forest cover type (predominant overstory species), 9) 2-3 dominant species of understory vegetation, and 10) tree density (trees/ha) (Reynolds et ale 1982, Moore and Henny 1983, Fischer and Murphy 1987). 4. Aerial photographs (1:24,000) of nest sites and proximate cover types will be used to plot nest locations with respect to surrounding cover types and aid in locating nests on subsequent visits. 5. Trapping of hawks will occur near nest sites with mist nests or dho-gaza traps made from mist nets following Bloom (1987). Data collected on captured birds will include sex (ascertained by tail length, wing chord, and weight measurements) (Mueller et ale 1976), stage of molt (Mueller et ale 1979, Clarke 1984), and age (categorized as hatching or 2nd-year juvenile, or adult) (Mueller et ale 1979). be banded with butt-end aluminum bands. Captured birds will �441 6. Because molt in accipiters overlaps with nesting, sharp-shinned hawks will be fitted with back-pack mounted (Dunstan 1972~, 1972~, Kenward 1985), lithium-powered transmitters made by Biotrack (Dorset, England). Transmitter packages weigh 4 g and 7 g which are approximately 4% of male and female body weights, respectively. expectancy is 10-12 weeks. Battery life Pulse rates will be regulated by mercury tilt-switches that change with activity (flight vs. perch). A maximum transmitting range of 2-3 km is expected depending on vegetation density and topography. 7. Two 3-element Yagi or whip antennas will be positioned at and near each nest site. Antennas will be elevated at least 3 m above the ground and will be used simultaneously or alternately to monitor hawk activity. At the end of an activity sampling period the antennas will be disassembled and reassembled at the next nest site. 8. telemetry: The following measures of activity will be obtained using 1) mean duration of perching bouts, 2) mean flight duration, 3) percent time spent in flight, and 4) periods of peak activity. 9a. Radio-monitoring of male sharp-shinned hawk activity will begin soon after marking and continue until the young fledge. Females will be radiomarked and monitored when they begin to assist the male with prey provisioning, generally 3-4 weeks post-hatch. 9b. Nest sampling frequency will depend partly on the number of nesting pairs radiomarked (goal = 4 nests visited/week). Sexes will be monitored for an equal number of systematically chosen days. Sampling will occur between 0500 and 2100 MDT, and consist of 3 systematically chosen 10-minute periods of continuous monitoring each hour (focal-animal sampling) (Altmann 1974). �442 9c. Fischer and Murphy (1986) visually monitored sharp-shinned hawks fitted with back-pack mounts and determined that fast-pulse signals of ~5 seconds between pulses corresponded to prey handling or preening behavior [defined as stationary activity bouts (SAB)], and signals of >5 seconds corresponded to flight in this species. length should correspond to perching. designations will be tested. A slow pulse of any Duration of said activity The mean value obtained for periods of stationary activity will distinguish SAB from flight. 9d. Analysis of activity patterns will be conducted using multivariate analysis of variance (MANOVA). Differences among cover types, sex, breeding phenology (days from nest initiation), time of day, nests within a cover type, and all interactions will be evaluated for dependent variable (1) mean duration of perching bouts, (2) mean duration of flying bouts, and (3) percent time in flight. The number of data points needed at each level to achieve a specified MANOVA power, given desired differences among means and significance levels, cannot be calculated ~ priori because data similar to the above were not found in the published literature. However, approximately 288 lO-minute sampling periods should be achieved for each nest by the end of the 1st field season. 10. Diurnal periods not used for radio-monitoring will be spent collecting and identifying prey remains and casts, collapsing and reassembling antennas, and traveling between sites. lla. A nest site observer will record frequency of prey deliveries and prey species. Prey consumed between nest visits will be reconstructed, identified, and counted by matching uneaten remains (remiges, retrices, and bills of birds, and skull fragments, fur, and �443 feet of mammals) (Reynolds and Meslow 1984). To avoid overestimating species abundance in the diet, regurgitated pellets (casts) and pluckings will be collected from plucking areas and nests at the beginning and end of each visit. In addition, prey items delivered to nestlings in each cover type will be simultaneously recorded by time-lapse cameras (2 cameras per cover type) that will run from dawn to dusk for 3 consecutive days each week. frame/min. Cameras will be mounted at nest-height and film 1 These data will confirm observed prey deliveries and augment delivery data for nests not observed. Mean weights for prey species will be obtained from the literature. lIb. Mean time between deliveries, and grams of prey delivered per minute (dependent variables) will be calculated for sex, cover type, stage of breeding, time of day, brood size, and nests within a cover type (independent variables). Differences among the independent variables will be evaluated for the dependent variables using a MANOVA model, the power of which cannot be calculated ~ priori because similar data are unavailable from the literature. Two-tailed student's t tests will be used to test for differences among mean size of prey delivered to nests in the 2 cover types (Zar 1984). Differences among mean prey size within cover type will be evaluated using chi-square contingency tables (Zar 1984). Each nest site will be observed for approximately 6 16-hour periods during the 1st field season. 12. The U.S. Forest Service will provide extensive data on abundance and distribution of bird and small mammal populations in the study areas. Systematic sampling using variable circular plot (Reynolds et ale 1980) and mark-recapture methods will provide quantitative estimates of avian and small mammal species composition and abundance in �444 aspen, conifer, and mixed aspen-conifer cover types, respectively, during the breeding seasons of 1988 to 1989. Twelve study plots have been selected in the 2 overs tory types (9 in aspen, and 3 in conifer). Bird sampling will occur from June to mid-July followed by small mammal sampling between mid-July and September. 13. Compile data, analyze results, and prepare progress and final reports. E. TIME SCHEDULE: Approach Date 1 September 1987 - December 1989 2a, 2b, 3, 4, 7, 10, lla May 5, 6 May - July 1988, 1989 8, 9a, 9b, 9c June - August 1988, 1989 9d, lIb, 12 September - April 1988, September - August 1988, 1989 December 1989 13 F. September - December 1987, 1988, 1989 PERSONNEL ASSIGNMENTS: Person Days 1987-88 Suzanne M. Joy Graduate Research Assistant Richard W. Hoffman Wildlife Researcher 220 11 1988-89 Suzanne H. Joy Graduate Research Assistant Richard W. Hoffman Wildlife Researcher 220 11 1989-90 Suzanne M. Joy Graduate Research Assistant Richard W. Hoffman Wildlife Researcher 132 11 �445 G. H. ESTIMATED COSTS: 1987-88 $14,084.00 1988-89 $14,598.00 1989-90 $ 8,000.00 SUPERVISION AND COOPERATION: Project Leader: Richard W. Hoffman, Wildlife Researcher, CDOW Principal Investigator: Academic Supervision: Collaborator: Cooperation: I. Suzanne M. Joy, Graduate Research Assistant, CSU Richard L. Knight, Assistant Professor, CSU Richard T. Reynolds, Research Wildlife Biologist, USFS USDA Forest Service LOCATION OF WORK: Study Headquarters: Department of Fishery and Wildlife Biology, Colorado State University, Fort Collins, Colorado 80523 Field Investigation: Forests. Gunnison, Grand Mesa, and Uncompahgre National Living quarters at West Muddy Guard Station, Gunnison National forest. Location of accipiter breeding pairs will determine individual study areas. J. RELATED FEDERAL AID PROJECTS: None LITERATURE CITED: Altmann, J. 1974. Observational study of behavior: sampling methods. Behaviour 49:227-267. Bailey, A. M., and R. J. Niedrach. 1965. Denver Mus. Nat. Hist., Denver, CO. Bent, A. C. 1937. Birds of Colorado. Vol. 1. 454 pp. Life histories of North American birds of prey. U.S. Natl. Mus. Bull. 167. 409 pp. Part 1. �446 Bloom, P. H. 1987. Capturing and handling raptors. Pages 99-123 in B. A. G. Pendleton, B. A. Millsap, K. W. Cline, and D. M. Bird, eds. management techniques manual. Raptor Natl. Wildl. Fed., Washington, D.C. 420 pp. Brown, L., and D. Amadon. Vols. 1 and 2. 1968. McGraw-Hill Book Co., New York, NY. Bull, J., and J. Farrand, Jr. North American birds. Clarke, R. G. Eagles, hawks and falcons of the world. 1984. 1983. 944 pp. The Audubon Society field guide to Alfred A. Knopf, Inc., New York, NY. 784 pp. The sharp-shinned hawk (Accipiter striatus vieillot) in interior Alaska. M.S. thesis, Univ. Alaska, Fairbanks. Craighead, J. J., and F. C. Craighead, Jr. 1956. 130 pp. Hawks, owls and wildlife. Stackpole Co., and Wildl. Manage. Inst., Harrisburg, PA and Washington, D.C. 443 pp. Crouch, G. L. 1983. Effects of commercial clearcutting of aspen on understory and wildlife habitat values in southwestern Colorado. For. Servo Res. Paper. DeByle, N. V. 1985. Winokur, eds. States. Dunstan, T. C. RM-246. Wildlife. Aspen: U.S. Dep. Agric., 8 pp. Pages 135-152 in N. V. DeByle and R. P. ecology and management in the western United U.S. Dep. Agric., For. Servo Gen. Tech. Rep. RM-119. 1972a. A harness for radio-tagging raptorial birds. Inl. Bird Band. News 44:4-8. 1972b. Radio-tagging falconiform and strigiform birds. Raptor Res. 6:93-102. Farley, J. A. 1923. Breeding of the goshawk in Massachusetts. Auk 40:532- 533. Fischer, D. L., and J. R. Murphy. 1986. Daily activity patterns and habitat use of coexisting Accipiter hawks in Utah. Unpubl. ms. 28 pp. �447 ----- , and 1987. Utah. Unpubl. ms. Foraging and nesting habitat of Accipiter hawks in 33 pp. Fitch, H. S., B. Glading, and V. House. nesting and predation. Flack, J. A. 1976. America. 1946. Observations on Cooper hawk Calif. Fish and Game 32:144-154. Bird populations of aspen forests in western North Ornithol. Monogr. 19. Green, A. W., and D. D. Van Hooser. Mountain states. 97 pp. 1983. Forest resources of the Rocky U.S. Dep. Agric., For. Servo Resour. Bull. INT-33. 127 pp. Gromme, o. J. 1935. Wisconsin. Hennessy, S. P. The goshawk (Astur atricapillus atricapillus) nesting in auk 52:15-20. 1978. Ecological relationships of accipiters in northern Utah--with special emphasis on the effects of human disturbance. thesis. Utah State Univ., Logan. Johnston, B. C., and L. Hendzel. M.S. 66 pp. 1985. Examples of aspen treatment, succession, and management in western Colorado. Serv., Rocky Mtn. Reg., Lakewood, CO. U.S. Dep. Agric., For. 164 pp. Jones, R. J., R. P. Winokur, and W. D. Shepperd. 1985. Management overview. Pages 193-195 in N. V. DeByle and R. P. Winokur, eds. and management in the western United States. Aspen: ecology U.S. Dep. Agric., For. Servo Gen. Tech. Rep. RM-119. Kenward, R. E. 1985. Raptor radiotracking and telemetry. I. Newton and R. D. Chancellor, eds. Pages 409-420 in Conservation studies on raptors. Paston Press, Norwich, England. Moore, K. R., and C. J. Henny. 1983. Nest site characteristics of three coexisting accipiter hawks in northeastern Oregon. Morgan, M. D. 1969. Nat. 82:204-228. Raptor Res. 17:65-76. Ecology of aspen in Gunnison County, Colorado. Am. MidI. �448 Muegg1er, W. F. 1985. Vegetation associations. and R. P. Winokur, eds. United States. Aspen: ----- , and ecology and management in the western U.S. Dep. Agric., For. Servo Gen. Tech. Rep. RM-119. Mueller, H. C., and D. D. Berger. hawk. Pages 45-55 in N. V. DeByle 1967a. Fall migration of the sharp-shinned Wilson Bull. 79:397-415. 1967b. ----- Some observations and comments on the periodic invasion of goshawks. Auk 84:183-191. and G. Al1ez. goshawks. Age and sex variations in the sizes of Bird Band. 47:310-318. _____ , and 1979. shinned hawks. Newton, I. 1976. 1978. nestlings. 1979. Age and sex differences in size of sharp- Bird Band. 50:34-44. Feeding and development of sparrowhawk Accipiter nisus J. Zool., Lond. 184:465-487. Population ecology of raptors. Buteo Books. Vermillion, SD. 399 pp. Platt, J. B. 1973. Habitat and time utilization of a pair of nesting sharp- shinned hawks (Accipiter striatus velox). Univ., Provo, UT. 1976. M.S. thesis, Brigham Young 41 pp. Sharp-shinned hawk nesting and nest site selection in Utah. Condor 78:102-103. Reynolds, R. T. 1983. Management of western coniferous forest habitat for nesting accipiter hawks. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. RM-I07. 1988. States. eds. The status of Accipiter populations in the western United Pages 000-000 in B. Pendleton, K. Steenhof, and M. N. Kockert, Proc. Western raptor management symposium and workshop. Wildl. Fed., Washington, D.C. (in press). Nat1. �44~ ----- , and E. C. Mes1ow. 1984. Partitioning of food and niche characteristics of coexisting Accipiter during breeding. ----- , and H. M. Wight. 1978. Distribution, density, and productivity of accipiter hawks breeding in Oregon. ----- , E. C. Mes1ow, and H. M. Wight. Accipiter in Oregon. ----- , for estimating bird numbers. 1957. 1987. 1980. A variable circular plot method Condor 59:373-393. Field guide to the birds of North America. J. A. Whelan, and P. L. Svoboda. management. Nesting habitat of coexisting Condor 82:309-313. Geograph. Soc., Washington, D.C. ----- , 1982. An analysis of avifaunas in the Teton Mountains and Jackson Hole, Wyoming. Scott, S. L. Wilson Bull. 90:182-196. J. Wi1d1. Manage. 46:124-138. J. M. Scott, and R. A. Nussbaum. Salt, G. W. Auk 101:761-779. Nat1. 464 pp. 1980. Cavity nesting birds and forest Pages 311-324 in R. M. DeGraff and N. G. Tilghman, eds. Management of western forests and grasslands for nongame birds. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. INT-86. Shuster, W. C. 1976. Northern goshawk nesting densities in montane Colorado. West. Birds 7:108-110. 1980. Rockies. Storer, R. W. Northern goshawk nest site requirements in the Colorado West. Birds 11:89-96. 1966. accipiters. Watte1, J. Sexual dimorphism and food habits in three North American Auk 83:423-436. 1973. Geograpic differentiation in the genus Accipiter. Ornitho1. Club, Bull. 13, Cambridge, MA. Weber, W. A. CO. 1976. 479 pp. Rocky mountain flora. Nuttall 231 pp. Colo. Assoc. Univ. Press, Boulder, �450 Wengert, E. M., D. M. Donnelly, D. C. Markstrom, and H. E. Worth. utilization. Aspen: 1985. Wood Pages 169-180 in N. V. DeByle and R. P. Winokur, eds. ecology and management in the western United States. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. RM-119. Zar, J. H. 1984. Cliffs, NJ. Prepared by Biostatistical analysis. 718 pp. __ ~=-=-()..,-:.(J..l._-:-:--'-'V--1~-L..&_'..;_. Q~~~ tTu Su~ H. Joy Graduate Research Assistant Wildlife Researcher Prentice-Hall, Inc., Englewood �JOB PROGRESS REPORT Colorado State of: Project: 01-03-045 : Job Avian Research 5 Work Plan: 21 Job Title: Evaluation of Habitat Quality on Conservation Reserve Lands in Eastern Colorado Period Covered: Author: 01 July through 31 December 1987 Warren D. Snyder Personnel: L. Benson, D. Bowden, C. Braun, L. Groshans, and W. Snyder, Colorado Division of Wildlife ABSTRACT The general distribution of Conservation Reserve (CR) i~ eastern Colorado through the first 4 signups was obtained and a·map was prepared. Field inspections revealed that the vast majority of the CR acreages were planted to temporary cover crops in 1987 and seeding began on these in November 1987 and will continue through April 1988. Among fields in southeastern Colorado seeded in fall to spring 1986-87, poor to fair grass stands were evident in fall 1987 and annual forbs dominated providing fair to good brood and winter cover on most. Planning and design for field sampling continued in cooperation with personnel of the National Ecology Center of the USDI Fish and Wildlife Service. ��453 EVALUATION OF HABITAT QUALITY ON CONSERVATION RESERVE LANDS IN EASTERN COLORADO Warren D. Snyder P. N. OBJECTIVES To determine the distribution and quantity of Conservation Reserve land in eastern Colorado in relation to the distribution of selected wildlife species; to evaluate the quality of the vegetation on these lands for selected wildlife species; to measure the response of selected wildlife species "to Conservation Reserve using existing annual surveys, and to evaluate the impact of the Colorado Division of Wildlife's cost share program on cover quality. SEGMENT NARRATIVES 1. Obtain the"legal description or plotted map location of all tracts signed into the Conservation Reserve Program through February 1987 in all eastern Colorado counties. Names of landowners, acreages, CR practice applied, seeding schedule, and other pertinent information will be obtained. 2. Design sampling scheme. for enacting stratified random sampling based on the intensity of commitment to CRP per county, the quality of the cropland, and the grasses seeded into the tract. 3. Evaluate habitat quality within selected CRP tracts (potentially using Natural Resource Inventory tracts as a basis for sampling) as Colorado's portion of a national monitoring program using appropriate habitat suitability index models for selected wildlife species. 4. Measure the response of selected wildlife species to conservation reserve using existing annual population surveys. 5. Monitor the height-density and general composition qualities of vegetation within a stratified random sample of CRP tracts in relation to randomly selected proximal controls. 6. Monitor the quality of tracts cost-shared by the CDOW (for enhancement of cover quality) with proximal tracts not cost-shared. 7. Show relationship of CRP distribution to that of selected wildlife species using computer mapping facilities. 8. Compile and analyze data, and prepare progress reports. RESULTS AND DISCUSSION District offices of the USDA Soil Conservation Service (SCS) within 23 eastern Colorado counties were contacted in spring and early summer 1987 to obtain information on the distribution of Colorado Reserve (CR) lands in eastern �454 Colorado. Some SCS personnel already had the distribution tallied by location or plotted on county maps whereas it was necessary to extract the essential data from individual files at some offices. The data were compiled per township and plotted on a map of eastern Colorado (Fig. la and lb) based on CRP as a percent of the total land per township. As the Figures illustrate, the majority of the CR lands were located within the southeastern quarter of Colorado in locations traditionally considered marginal for dryland farming and for farm game wildlife. The data summarize findings from the first 4 CRP sign-up intervals. Seven counties, located in southeastern Colorado (Fig. 2) had reached their respective quotas of eligible CRP acreage by the fourth sign-up. Two additional sign-up intervals have occurred since then but data are not yet available as to CR increases within counties that had previously not reached their quotas. A comparison of CR land in relation to total cropland/township would provide meaningful data but a source for cropland/township could not be found. Following discussion of study design and sample size with D. C. Bowden, consulting statistician, eastern Colorado was stratified into 7 units (Fig. 3). A random list of CR fields was obtained within each stratum for use in monitoring vegetation quality. The location and conditions within some of these tracts in extreme southeastern and northeastern parts of Colorado were obtained in fall 1987. A new random list of sample fields was provided to the Colorado Division of Wildlife by personnel of the National Ecology Center (NEC) of the USDI Fish and Wildlife Service. This list includes a minimum of 68 contracts and probably >100 fields so probably will preempt most of the previously obtained random sample. It is part of a coordinated effort to evaluate the Conservation Reserve for wildlife on a regional and national basis. Field data collection procedures, developed for the Southern Great Plains Region which includes Colorado, will be supplemented where deemed necessary to obtain data deemed pertinent to Colorado. Key indicator wildlife species for which sampling will be directed include the ring-necked pheasant (Phasianus colchicus), western meadowlark CSturnella neglecta), and cottontail (Sylvilagus spp.). Field inspections in fall 1987 indicated that the majority of the CR fields had been planted to a sorghum cover crop in summer 1987 and would be seeded to perennial grasses from November 1987 through April 1988. Sorghum cover was primarily of sterile varieties that varied by field and locality in height, density, and standability. Some fields provided good over-winter cover to pheasants and other wildlife but most would be classed as fair to marginal in protective quality. Up to a third or more of the CR tracts in the southeastern corner of Colorado had been seeded to permanent (perennial) cover. Side-oats (Bouteloua curtipendula) appeared to be one of the primary species being seeded. Seeded grass stand establishment ranged from poor to fair in most inspected fields and as would be expected, had not attained significant growth of cover value during their first growing season. Wild annuals dominated in all fields and varied widely in species, height, and density primarily among fields. Some provided excellent brood and winter habitat for pheasants, whereas others were sparse and/or short. Some had been mowed so provided little over-winter cover. Precipitation in southeastern Colorado had been generally favorable for grass stand establishment and for growth of annual weeds in 1987. �455 o '"0 ~ ~ o U o rl c (l) 1..; ~ til (l) rU ;C ~ l.; o c C 'rl ~ ~ (l) til (l) 0:: C o rU +l -rl til (!J :> ~ o C u c ~ o :s o -rl ~ til ~ ~ ~ o -rl �~ V1 (J"\ SYMBOL 0 • • - PERCENT CRP < N 1.0 1.0 - 2.4 2.5 - 4.9 5.0 - 9.9 10.0 - 14.9 15.0 - 19.9 20.0 - 24.9 25.0 & > Fig. 1bo Distribution of Conservation Reserve in southeastern Colorado through February 1987. �457 Fig. 2 Reserve Percent of eligible cropland Program by county in eastern committed Colorado, to the spring Conservation 1987. �458 WELD l F~g. 3 Strata deliniated for selection Conservation Reserve. tracts in eastern of random Colorado, samples 1987. of �459 Many of the CR tracts within southeastern Colorado were surrounded on one or more sides by shortgrass rangeland. During cover crop and early stand stages when they are dominated by annuals they will retain diversity. However, in future years when they revert to perennial grasses interspersion of covers will decline. Most of these fields are extremely marginal for farming so as they are reverted to perennial cover, wind erosion should also decline markedly. Monitoring of pheasant densities using crowing count indices was conducted, primarily by management personnel in spring, 1987 and census data were compiled for future use. Compilation of historic pheasant crow-count data also was initiated. However, few crowing censuses have been conducted in recent years so 1987 data will be the primary pre-CR data available. Maps of the breeding bird survey (BBS) and mourning dove (Zenaida macroura) census routes in eastern Colorado were acquired and historic BBS data were provided by Sam Droege (USDI Fish and Wildlife Service) and Clait Braun. Prepared by "UJ~ ~ warren D. Snyder Wildlife Researcher C ��JOB PROGRESS REPORT State of: Colorado Project: W-152-R Avian Research Work Plan: 22 Job Title: Avian Research Publications Period Covered: Author: Job 1 01 January through 31 December 1987 Clait E. Braun Personnel: C. E. Braun, K. M. Giesen, M. A. Graham, E. J. Hernandez, J. W. Hupp, N. J. Kitzmiller, O. B. Myers, T. E. Remington, M. Schroeder, Colorado Division of Wildlife ABSTRACT Publications accomplished under this job in 1987 are: Braun, C. E. 1987. Current issues in sage grouse management. Assoc. Fish and Wildl. Agencies 67:134-144. 1987. Are sage grouse cyclic? Worksho p 15:18. Proc. West. Trans. Bien. West. States Sage Grouse Giesen, K. M. 1987. Evaluation of aerial and ground transects to inventory lesser prairie-chickens in southeast Colorado. Proc. Annu. Conf. Central Mountains and Plains Sect., The Wildl. Soc. 32:Abstract. 1987. Evaluation of aerial and ground trasects to inventory lesser prairie-chickens in southeast Colorado. Proc. Prairie Grouse Tech. Conf. l7:Abstract. 1987. Habitat use and preference by Columbian sharp-tailed grouse in northwest Colorado. Trans. West. States Sage Grouse Workshop 15:20. 1987. Colorado. Hovement and habitat use by Columbian sharp-tailed grouse in Proc. Prairie Grouse Tech. Conf. l7:Abstract. Graham, M. A., and C. E. Braun. 1987. Changes in territory size of whitetailed ptarmigan. J. Colorado-I-lyomingAcad. Sci. 19(1):20. Hernandez, E. J. sage grouse. 1987. Fire in the big sagebrush type: potential impacts on Trans. Bien. West. States Sage Grouse l-lorkshop15:14. �Hupp, J. W. 1987. A test of the relationship between sage grouse lipid reserves and courtship behavior. Trans. Bien. West. States Sage Grouse Workshop 15:19. 1987. Winter distribution, foraging ecology, and habitat use of sage grouse in the Gunnison Basin, Colorado. Trans. Bien. West. States Sage Grouse Workshop 15:10. Kitzmiller, N. J., and C. E. Braun. 1904-1985. J. Parasit. 73:679. 1987. In memoriam, Robert M. Stabler, Myers, O. B. 1987. Sagebru~h fertilization: will sage grouse respond? Trans. Bien. '\~est.States Sage Grouse Workshop 15:11. Remington, T. E., and C. E. Braun. 1987. Carcass composition and energy reserves of sage grouse during winter. Condor 90:15-19. Schroeder, M. 1987. to 1ek location. Prepared by Movement of female greater prairie-chickens in relation Proc. Prairie Grouse Tech. Conf. 17:Abstract. t/dz ~ ~C~l-a~i~t~E~.~B~r-a-u-n--~~~~~~-----Wildlife Research Leader �JOB FINAL REPORT Colorado State of: Project: W-152-R (01-03-045) Avian Research Work Plan: 24 Job Title: Roost Site Selection of Whooping Cranes at Fall Migration Stopover Sites Period Covered: Author: : Job 1 01 January 1986 through 31 August 1988 Tanya M. Shenk Personnel: R. J. Behnke, D. A. Hein, B. Van Horne, Colorado State University; C. E. Braun, J. K. Ringelman, Tanya N. Shenk, Colorado Division of Wildlife ABSTRA.CT Roost site selection by whooping cranes (Grus americana) was investigated during the 1986 and 1987 fall migration periods at traditional stop~ver sites (TSS) and non-traditional stopover sites (NTSS) in Colorado. Common characteristics among 35 TSS roosting wetlands in the San Luis Valley (SLV) included areas of water depth <30 cm, extensive horizontal visibility, and close proximity to feeding sites, loafing areas, and similar wetlands. Other characteristics that showed no consistency among TSS roosting wetlands included wetland size, emergent vegetation composition and density, specific conductivity of water, and distances to power lines, fences, and potential disturbances such as roads and residences. Three roost sites were used by 2 Grays Lake whooping cranes at NTSS in eastern Colorado. One NTSS was used during fall 1985,.a second NTSS was used by the same whoping crane during fall 1985 and 1986 •. Characteristics common among 3 NTSS roosting wetlands included areas of water depth <30 cm, isolation from disturbance, and close proximity «2 km) to feeding sites, loafing areas, and similar wetlands. There was no consistency among the lITSS wetlands for percent of horizontal visibility or vegetation composition and density. Mean length of stay for 16 whooping cranes in the SLV was 37.3 days (SD = 8.6). Males and females stayed in the region for the same length of time, however, variance of stopover duration was greater for males than females (F = 16.63, ~ = 0.003), primarily due to the broader range of departure dates for males. Sexes did not differ in the distances flown from one activity site to the next. Distances flown from the roost sites to feeding sites were greater than distances flown from feeding sites to loafing areas. Greatest site fidelity was exhibited for roosting complexes. Site fidelity did not differ among feeding sites, loafing areas, and roost sites within a roosting complex. Most (65%) loafing areas were within roosting complexes. The �non-roost complex loafing sites, located nearer feeding sites than roost complexes, were used when greater distances were flown from roost site to feeding site (~ = 0.04). Behavior of a female subadult whooping crane was described at a NTSS (eastern Colorado) and a TSS (SLV) during the 1986 fall migration. Time budget data were collected on this crane during all diurnal activity periods at the NTSS, and during feeding periods at the TSS. The frequency of alert behavior increased and foraging time decreased when feeding alone at the NTSS compared to behavior when feeding with a flock at the TSS. Daily activity patterns at the NTSS were consistent with those of the whooping cranes of the Grays Lake flock using TSS. �465 ACKNOWLEDGMENTS This project was supported by the Colorado Division of Wildlife (CDOW) and Colorado State University. Funding was provided by the CDOW through Federal Aid in Wildlife Restoration Project 01-03-045, 16700. Special thanks are extended to Dr. J. K. Ringelman, CDOW, for the assistance, counsel, and encouragement given me throughout all aspects of the project. I am especially grateful for his patience and the instructive criticisms received during preparation of this thesis. Appreciation is expressed to Dr. D. A. Hein, Professor of Wildlife Biology, his thoughtful suggestions and comments concerning professional ethics will serve as guidelines in future decisions. I also thank my graduate committee members Dr. B. Van Horne, Assistant Professor of Biology, for her assistance in study design and thesis preparation and Dr. R. J. Behnke, Professor of Fishery Biology, for his unique, insightful comments on this study and ecology as a whole. Dr. C. E. Braun, CDOW, was instrumental in supporting and funding this project through to completion. I am grateful to Or. R. C. Drewien and W. M. Brown for sharing their extensive field knowledge of crane behavior, particularly whooping cranes of the Grays Lake flock. I will remember the 1986-88 graduate student cohort and faculty with a fond smile and sense of kinship. To share with them the experience of the satisfaction of accomplishments and the inevitable �466 disappointments of field work, course work, thesis preparation, and personal growth was one of the most rewarding facets of my degree. May we continue to play hard and work hard as biologists and as individuals. My parents, sisters, brother, nieces, and nephews unconditionally supported me with their love and faith. reach my goals. thank them for helping me �467 Table of Contents ABSTRACT OF THESIS ...........•....•.•.•....•.•..•••••.•......••.•... Pace iii ACKNOWLEDGMENTS ........•.•..••.••.•..••.......•..•..•....•••••••...... v Chapter 1. ROOST SITE SELECTION OF WHOOPING CRANES IN THE SAN LUIS ----VALLEy, COLORADO....••.•..••......•.•.•..••..............• 1 Summary .................•....................•..........•........ 1 Study 5 Area Methods ...................•...................................... 6 Resul ts ...........•......•.•.•.................•..•.. Discussion Literature 2. .................•.......................•...........• 38 A .•...••.....•••••....••..........••.•....••..•.••..... 41 WHOOPING CRANE BEHAVIOR AT TRADITIONAL AND NON-TRADITIONAL FALL MIGRATION STOPOVER SIT£S Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Study 9 27 Cited ..........•....•.........••................•...• Appendix Chapter " Area .•..........•........................................ 48 . 48 50 Methods ........•............................................... 51 Resul ts ..................•..................................... 53 Discussion 60 Literature ..................•.............•.................... Cited ••......•.........................•.....•...... 65 Append i x B...............................•.........•........... 68 Appendix 89 C..............................................•...... �468 Table of Contents (cont/d) Paae Chapter 3. ROOST SITE SELECTION OF WHOOPING CRANES AT NON-TRADITIONAL FALL MIGRATION STOPOVER SITES IN EASTERN COLORADO 95 Summary 95 Study Area 97 Methods '.' Resul ts 97 98 Discussion 103 Literature Cited 108 Appendix D Chapter 4. ; 110 MANAGEMENT IMPLICATIONS 114 �4b~ CHAPTER 1 ROOST SITE SELECTION OF WHOOPING CRANES IN THE SAN LUIS VALLEY, COLORADO SUMMARY Roost site selection invesfigated Luis Valley and loafing cranes (Grus americana) during the 1986 and 1987 fall migtation (SLV), Colorado. for roosting wetlands. Habitat characteristics Juxtaposition period. of individual Common characteristics included wetland conductivity and potential cranes during horizontal that showed no consistency size, emergent vegetation of water, disturbances of stay for 16 whooping sites, was investigated each visibility, to feeding sites, loafing areas, and similar Other characteristics specific feeding among 35 roost sites included areas of water depth < 30 cm, extensive close proximity in the San were evaluated of roost sites, whooping was periods areas as a factor in roost site selection using daily locations activity by whoo~~~g wetlands. among roost sites composition and distances and and density, to power lines, such as roads and residences. fences, I~ean length in the SLY was 37.3 days (SO = 8.6). cranes Males and females stayed in the region for the same length of time, however, of stopover females departure variance (£ = 16.63, £ = 0.003), dates for males. from one activity duration was greater for males than primarily due to the broader range of Sexes did not differ in the distances site to the next. Distances flown flown from roost sites �470 to feeding sites were greater to loafing areas. complexes. Greatest Site fidelity than distances site fidelity was exhibited sites, located roosting complexes. complex. sites for roosting did not differ among feeding areas, and roost sites within a roosting areas were within flown from feeding sites, loafing Most (65%) loafing The non-roost complex loafing nearer feeding sites than roost areas, were used when greater distances site (£ = were flown from roost site to feeding 0.04). Suitable roosting, stopover feeding, to complete rivers, migration a combination in good condition. roosting and feeding A primary delineate migration objective remaining (Whooping information (Whooping considerable about their ecolDgical studies Aransas-Wood as critical migration Team 1980). migration the potential periods crane recovery (Lingle plan is to stopover sites for Before additional habitat is needed on the characteristics Crane Recovery Despite suitable Crane Recovery areas can be designated specific thereby eliminating of the whooping cranes wetlands, throughout sites for cranes during stopover and protect this species corridor, of for whooping Unfortunately, and streams have been altered or destroyed cranes' Several which includes and loafing sites, is necessary whooping 1987). habitat, however, more of stopover sites Team 1980). research on whooping cranes, little is known requirements during migration (Howe 1987). have been conducted on the migration ecology Buffalo (AWB) population (Allen 1952; Johnson 1980; Lingle et al. 1984, 1988; Howe 1987; Ward and Anderson These studies were limited by too few observations of the and Temple 1987). each season, the �471 isolation of stopover sites (Johnson that was biased by the distribution 1981), or a scarcity of marked 1987). studies No intensive requirements migration marked respects ecology. have been conducted cross-fostered activity population through Colorado and Bizeau sandhill Wildlife and Derrickson cranes Refuge, NWR, New Mexico 1981). these cranes usually site for several and comparison of daily stay, and (2) cranes and the Rocky Mountain (Grus canadensis 1974, 1978, Kauffeld tabida) migrate grounds Idaho to their wintering (Drewien and Bizeau The San Luis Valley spring and fall migration spending of duration. use the SLV from mid-February November, and (3) effects stopover flock of whooping near Bosque del Apache is the major traditional (1) of each bird to each fall in route from their breeding Grays Lake National on sites and loafing and among birds over an extended of stopover of greater crane flock. exist to document: Additionally, (1) observation within The cross-fostered whooping (2) site fidelity behavior. located allowing: patterns documentation Erickson cranes; on individual weeks thereby (Howe on the migration feeding a season and over years; remain at a centrally (Ellis et al. since all birds of this flock are from the roost to specific areas used by individual disturbance data this flock better lends itself to studies For example, roost sites within locational within the population (Melvin et al. 1983) the opportunities flight distance 198Q), of trained observers individuals of the experimental Yet in several and Temple grounds 1974, (SLV) of Colorado stop for these cranes 1981, Brown et al. 1987). (Drewien Both species to early May and from late August more time in the Valley near to mid- than in either their summer �472 or winter ranges (Drewien and Bizeau 1974, Kauffeld 1981, Brown et al. 1987). Cross-fostered occasionally whooping Prog. Rep. Whooping Similar associations behavior larger wetlands migrate Crane Egg Transplant occur at roost sites in the SLV. may be needed to accommodate cranes as individuals and Derrickson 1981). or in pairs, families, reared flock have also been observed of sandhill cranes, pairs, families, 1981, Johnson whooping species. whooping and Temple 1980). cranes migrating sightings, Investigation and roosting with flocks and less frequently as and Derrickson et al. (1976) reported cranes in 14% of their requirements may be similar for the 2 of roost site selection provide of both naturally-reared may cranes and normally (Allen 1952, Erickson Archibald cranes could therefore Specifically, cranes within the naturally- migrating with sandhill hence migration requirements Such gregarious or small flocks (Erickson most often as individuals and larger groups 1-20). Naturally-reared than sandhill However, whooping (R. a flock, and isolation with added flock vigilance. are less gregarious or cranes Experiment may effect their roost site selection. be less important whooping as individuals, in groups of 2 or 3, within a flock of sandhill C. Drewien, roosting cranes usually migrate by the cross-fostered information on the ecological and cross;fostered whooping crane flocks. The objectives and biological whooping characteristics cranes juxtaposition of this study were to: (1) quantify the physical of roost sites used by cross-fostered in the SLV, and (2) relate roost site selection of habitats during the fall stopover used by individual period. to the cranes of this flock �473 STUDY AREA The study was conducted in and around the Monte Vista-Alamosa within the SLV of Colorado. of Colorado's The SLV is the largest 4 intermountain parks. the west by the San Juan Mountains Cristo Mountains, (Ryder 1951). and southern-most The Valley, which is bordered on and on the east by the Sangre de is 161 km long and 81 km across at its widest point The Rio Grande, flowing through the central parts of the valley in a southeasterly Alamosa and Conejos rivers, relatively NWR direction, is joined here by the its main tributaries. flat surface that rises gradually the north, east, and west. Elevations and southern The basin has a toward steep mountains to range from 2100 m at the south end of the Valley to about 2400 m at the base of the mountains (Hopper 1968). The high elevation produces a climate and rain shadow effect of the San Juan Mountains classified annual precipitation as "cold desert" (Anderson ranges from < 18 em in the central 1965). Mean part of the valley to 25 cm around the edges of the valley floor (Ryder 1951). Despite the arid climate, table and numerous (Anderson 1965). impervious artesian wetlands Most important sub-strata that are valuable are also associated The principle husbandry. Alfalfa oats predominate; industry and marshes, but oxbow ponds with the SLV river systems. is irrigated and irrigated to waterfowl are large tracts of flooded hay and pasture lands, as well as drain ditches and sloughs create a high water farming and cattle and sheep pasture grasses, other crops such as lettuce, potatoes, cabbage, peas, and spring wheat are grown in lesser amounts. barley and cauliflower, The alkaline and �474 saline conditions caused by the high water table restrict to only the most alkaline-tolerant The Monte Vista National shrubs and grasses. Wildlife south of Monte Vista in the western production habitat plant growth Refuge (MVNWR), located 3.8 km portion of the SLV, is managed area for waterfowl. The 5758-ha refuge also provides for cranes, waterfowl, and other birds during migration, winter habitat for waterfowl leucocephalus). Artesian control water and pump wells located throughout The Alamosa Alamosa. This 4520-ha wetlands and is bordered and and bald eagles (Haliaeetus levels and maintai~ and waterfowl. as a roosting the refuge and loafing areas for cranes NWR (ANWR) is located 1.9 km southeast refuge is composed of natural of riverbottom on the west by the Rio Grande River. METHODS Criteria information cranes for habitat evaluations concerning habitat requirements (Allen 1952; Johnson Howe 1987; Ward and Anderson measure were based on published 1987). Variables (1) distances as fences and power lines and to potential optical measured maps were consulted. with a portable from aerial profiles and farm buildings. and techniques to potential disturbance photographs derived each wetland. perpendicular 2) Specific conductivity meter. and/or topographic from transects established Water depth was measured distance to shoreline used to hazards such sites including If these objects were < 180 m, an range finder was used to measure distance, topographic whooping and Temple 1980; Lingle et al. 1984, 1988; them were as follows: roads, houses, of migrating otherwise conductivity 3) Wetland maps. of water size measured 4) Water depth at 10-m intervals along each transect; was recorded across then for water depths of �475 10, 20, 30, and 40 cm. Contour lines at these 4 water depths were drawn to create a water profile for each wetland. visibility divided measured with a 3-m high vegetation 5} Horizontal profile board that was into O.S-m sections, with the first 0.5 m section sub-divided into 0.2S-m intervals increments (Nudds 1977). Viewing points were set at 10-m along the 20-cm water depth contour of the wetland. viewing point, a 90-m transect was established shoreline perpendicular or stand of dense emergent vegetation, was measured. Habitat evaluations From the to the and percent visibility were conducted on 35 roost sites over 2 years. Whooping November cranes were observed in the SLV from 28 October through 8 1986 and from 23 September arrival, departure, and daily activities , recorded only during 1987. cranes during roosting, periods were obtained binoculars. through 21 November of individual Daily locations morning feeding, 1987. Dates of birds were of individual whooping loafing, and evening feeding from a vehicle with a 30x spotting Average length of stay was calculated males and compared with a t-test; variances scope and 7xSO for females and were compared with an F- test. Individual cranes were initially site, then the direction noted. at the morning roost of flight to the morning feeding site was Birds were located on feeding sites either by searching them from roads or by following habitat type to another. an individual loafing site. an individual for bird as it flew from one The location of feeding sites was recorded quarter section of the field. watching identified by Loafing areas were best located by bird fly from the morning feeding site to the Evening roost sites were located either by following an �476 individual driving bird from the evening feeding site to the roost or by into a roost area near sunset when birds were first flying in to roost, then observing The sequence which birds flew into that site. of diurnal habitat use by cranes (Ellis et al. 1981, Kauffeld approximately one-half is well documented 1981): (1) cranes fly from the roost site hour before sunrise to the morning where they remain until late morning; (2) thereafter they fly to a loafing area where they remain until late afternoon; fly to feeding sites (often the same location where they remain until approximately feeding site, (3) cranes then used in the morning) one-half hour after sunset; (4) after which they return to the roost site where they remain through the night. Inter-site distances which an individual distances site to morning area (AMFSLA), evening averaged Location site (AMRSFS), morning activity periods were measured over individuals. Distance AMRSFS, sexes and between Site fidelity different AMFSLA, site (PMLAFS), Distances consecutive activity was calculated roost on topographic measurements and flown between maps and to and from feeding field quarter section. PMLAFS, and PMFSRS were compared sites used expressed observations periods: feeding site to loafing loafing area to evening feeding site to roost site (PMFSRS). periods by mean activity sites were taken from the center of the recorded Distances diurnal cycles in data were also grouped flown between consecutive feeding feeding consecutive for complete bird was located during all 5 activity , within the same day. individual were measured between periods. for each bird as the number of as a percentage of the total number of for that bird durjng a given activity period (e.g. 22 �477 different feeding observations). fidelity. sites used by bird 76-7 for 55 feeding period Low values for this quotient Comparisons roost complexes, categorized feeding sites, and loafing areas. complex (RCLA), and (2) complex (NRCLA). Wilcoxon a roosting were used on a given day, averaged Because of small sample sizes rank-sum tests were used for all distance comparisons. in this study was set at ~ a roosting PMLAFS, and PMFSRS distances crane and compared. data and site fidelity Loafing areas were loafing areas located outside by loafing area catagories and non-normality, of roost sites, (1) loafing areas located within AMRSFS, AMFSLA, for each whooping high site were made among site fidelities by location: then separated indicated = Level of statistical significance 0.05. RESULTS One juvenile and 21 subadult and adult whooping cranes were observed using 18 roost sites in the SLV during the 1986 fall stopover period. In 1987, one juvenile cranes were observed and 17 subadult and adult whooping using 27 roosting wetlands. located in 1987 had also been used in 1986. Ten of the 27 roosts Of 8 roost sites used in 1986 but not used in 1987, 6 were dry during fall 1987. roost sites were located during the 2 stopover Locations the MVNWR, within of the 35 roosts included 9 wetlands A total of 35 periods. 1 site on the ANWR, 10 sites on located within 1 km of the Rio Grande River, 11 1-2 km of the river, and 1 roost site within river. The 3 remaining MVNWR. All roost sites were located within 1.1), which were defined roosting wetlands 2-3 km of the were within 0.5 km of the 10 roosting as a group of wetlands within complexes (Fig. 2 km of each �478 7S Roost Sites 11S I--------...J:..:.J:,L_- ___; 12S 1------_;___--__;__-;._JO,........_- __ --i ~ --i --Io::..I--l- 0 Feecmq Sites Loafing Sites r--r-; 16 Km Hwy 15 1E 2E 3E 4E 5E 6E 101 102 103 104 105 106 107 Fig 1.1. Distributicns of roost complexes, roost sites, feeding sites. ana loafing areas usea by whooping cranes in the San Luis Valley auring fail 1987. �479 other used as roost sites by whooping Whooping cranes used 1-10 wetlands Whooping in each complex. cranes used wetlands with a broad range of characteristics (Appendix A). ha, SO cranes and sandhill cranes. Size of wetlands ranged from 0.04 to 31.6 ha (~ = 7.2 9.6 ha). ~istance to potential (a roost adjacent to a road) to 1.9 km. = roads, and buildings were 982 m (SO 733 m (SO = 494 m) respectively. Mean distances wetlands Fences frequently (cells). 505 m), and ranged from 460 Two specific conductivities or were adjacent to ~istance from 0 m to 2220 m, with a mean distance first category = SO = 2293 mmhos/cm). dissected (~ = 84.4 m; SO = 123.9 m). Three catagories to houses, Specific conductivity sewage ponds from a starch factory registered >10,000 mmhos/cm. ranged from 0.0 km 535 m), 533 m (SO = (~ = 1162 mmhos/cm, to >10,000 mmhos/cm disturbance to power lines ranged of 471 m (SO = 431 m). of wetlands were used as roosts in the SLV. included 11 artificially created refuge wetlands Cells were flooded with well or ditch water, which collected in shallow uplands and in 2-m wide barrow pits behind dikes. depth at the barrow pit was> flooded area was controlled sites. (Eleocharis Greasewood spp.) were the dominant (Sarcobatus vermiculatus) these wetlands dominant especially generally flooded vegetation, visibility Size of the was only obstructed <0.5 m high (Fig. 1.2). into each sedges (Carex spp.), and the upland areas surrounding Horizontal < 20 cm. by the amount of water directed Baltic rush (Juncus balticus), spikerushes Water 40 cm, whereas water depth in the flooded uplands was < 30 cm with a large percentage cell. The plants on most of these was frequently present on and in some cases was the in recently flooded cells. by surrounding Five of these wetlands vegetation had dense �480 Refuge roosti1g wetlands (cells) 2.5-3.0 2.0-2.5 -E ._ 1.5-2.0 1.0-1.5 W I J i I I l .25-.50 / ""1 .> 0.5-1.0 (f) Z ....• j .i.> / 0-0.25 2 W 0 40 20 100 80 60 120 0: 0 Z Rio Grande River roosting oxbows 2.5-3.0 ..; \ I 0 0: 2.0-2.5 « 1.5-2.0 rn 1:0-1.5 0 \ J I j ./ .1 I / 0.5-1.0 W ...J u::: 0 a: a.. / .25-.50 ._ 0 <{ l- ui CJ W > / / /' 0-0.25 0 20 Flooded pasnre Z I 2.5-3.0 -I i 2.0-2.5 -J 40 80 100 80 120 and stock pond roosting wetlands I I 1.5-2.0 1.0-1.5 0.5-1.0 I J i I , I ,/ .~ / ! .25-.50 0-0.25 / i i / ! 0 / 20 40 60 80 100 120 PERCENT VISIBILITY Fig.l.2. Mean (± SO) horizontal visibility of 3 catagories of roosting wetlands from 90 m distance. �4bl cattail (IYQh£ latifolia) visibility and bulrush (Scirpus spp.) that obstructed up to 3.0 m high. Rio Grande oxbows made up the second category wetlands. Characteristic water depth profiles of roosting for oxbows deeply cut outer edge with a gently sloping inner bank. in the shallow water «30 cm) extending visibility obstructed by trees present along the river bank. vegetation was sparse probably obstructed at the 11 wetlands in this category of roosting wetlands consisted df low-growing stock ponds had no emergent Horizontal only obstructing and only was flooded pastures or submergent Water depths were always < 20 cm and generally types. was highly Understory as a result of grazing, Pasture vegetation grasses whereas Cranes roosted visibility. The third category stock ponds. a from the inner bank. Horizontal partially included visibility and meadow vegetation. < 10 cm in both wetland was high at all 13 sites, with vegetation view in the lowest 0.25 m (higher visual obstruction was a result of topography). Feeding sites were primarily and harvested potato fields. quarter section. geese. (roosting areas were located within roosting feeding intermittently Field size ranged from one-eighth to one- These fields were also used by feeding ducks and Loafing near distant cut, disced, or plowed barley fields sites (NRCLA). flooded greasewood complexes RCLA on the MVNWR were areas adjacent to roosting area A, on the MVNWR was grazed during fall 1987). river bottomland were flooded hay meadows NRCLA were irrigation within a feeding ditches adjacent (RCLA) or and cattle-grazed to a feeding site, and nearby greasewood areas. wetlands RCLA in pastures. site, flooded areas �482 Mean stopover duration for 16 whooping cranes using the SLV during the fall 1987 was 37.3 days (SO = 8.6 days; whooping eliminated from the mean calculation November; Pat 14 was also eliminated crane remained because it was found dead on 3 because I was informed that this in the SLV beyond the time of my last observation). (£ > 0.05) between the mean stopover duration There was no difference n of males (~ = 36.4, However, the variance = 9) and females (~ = 38.4, of stopover duration greater than for females dates for all whooping (s2 = 1.1; E n = 7, Fig. 1.3). for males (s2 = 16.63, £ = 0.003). cranes ranged from 23 September with 50% of the birds arriving October. crane 87-5 was 3.8) was Arrival to 12 October, in the 4-day period 29 September to 2 All females and 56% of the males departed within the 9-aay period 3-11 November. Fifteen individuals 1987 stopover period the 18 whooping observed were observed (Table 1.1). cranes present on roost sites. on roosts 174 times during the Three (Pat 7, Pat 10, and Pat 15) of in the SLV during fall 1987 were not I abandoned efforts to locate whooping cranes. Pat 7 and Pat 15 using areas near Hooper, Colorado because of the distance from the concentrated use area. only 17 days and was never observed Cranes exhibited individual = 0.002, £ Pat 10 remained in the SLV at a roost site. greater site fideli~y to a roost complex then to roost sites, feeding sites, or loafing areas (Table 1.2; 0.002, £ = 0.028 respectively). P Site fidelity did not differ among feeding sites, loafing areas, and roost sites within a roosting complex. hunting Roost complex fidelity was frequently (Table 1.3). hunting closure This effect was observed following between the first and second duck season. disturbed by the 12-day Opening day �483 16 15 14 (f) 0 0: rn LL 0 0: iu §2j FEMALES: 13 12 MALES 11 10 ;j m 6 ~5 =>4 Z 3 2 18 23 28 SEP 3 8 13 18 23 28 OCT 2 7 12 17 22 NOV Hunting Season DATE Fig. 1.3. Number of whooping cranes in the San Luis Valley on given dates during the 1987 stopover period. 27 �484 Table 1.1. Roost site locations of whooping cranes in the SLV during the 1987 fall stopover period. Bird Sex Date Roost Complex (Site) Use 76-7 M 23 SEP C(4) Hunted 25 SEP C(I) Hunted 26 SEP C(1) Hunted 27 SEP B(2) Non-hunted 29 SEP C( 1) Hunted 3 OCT o ( 1) Non-hunted 10 OCT O(l} Non-hunted 16 OCT C(2) Hunted 22 OCT 0(1) Non-hunted 23 OCT 0(2) Non-hunted 26 OCT H(1) Hunted 28 OCT 1(6) Hunted 30 OCT O(l) Non-hunted 1 NOV O(l) Non-hunted 4 NOV 78-10 M Last date observed 8 OCT 1(2) Hunted 14 OCT F(I) Hunted 18 OCT F(3) Hunted 21 OCT F(3) Hunted 27 OCT F(1) Hunted 30 OCT F(1) Hunted 4 NOV H(l) Hunted �485 Table 1.1 (cont.). Roost site locations of whooping cranes in the SLV during the 1987 stopover period. Bird Sex 78-10 M 79-7 83-8 M M Date Roost Complex (Site) Use 5 NOV H (1) Hunted 6 NOV H{l) Hunted 8 NOV H(1) Hunted 9 NOV 0(2) Non-hunted 10 NOV 0(2) Non-hunted 11 NOV 0(2) Non-hunted 12 NOV 0(2) Non-hunted 13 NOV Last date observed 30 SEP 1(2) Hunted 8 OCT I(2) Hunted 29 OCT I{S) Hunted 31 OCT I(5) Hunted 1 NOV I(2) Hunted 2 NOV I(9) Hunted 4 NOV Last date observed 16 OCT C(2) Hunted 22 OCT 0(2) Non-hunted 30 OCT 0(1) Non-hunted 31 OCT 0(1) Non-hunted 1 NOV 0(2) Non-hunted 6 NOV 0(1) Non-hunted 7 NOV 0(1) Non-hunted �486 Table 1.1 (cont.). Roost site locations of whooping cranes in the SLV during the 1987 stopover period. Bird Sex Date 83-8 M 10 NOV Pat 4 M 2 OCT Pat 6 M Roost Complex (Site) Use Last date observed I(unknown) Hunted 11 OCT F(2) Hunted 12 OCT F(I) Hunted 13 OCT F(2) Hunted 17 OCT F(2) Hunted 18 OCT F(3.) Hunted 19 OCT F(l) Hunted 20 OCT F(2) Hunted 27 OCT F(l) Hunted 29 OCT F(I) Hunted 30 OCT F(l) Hunted 1 NOV 0(1) Non-hunted 8 NOV O(l) Non-hunted 8 NOV Last date observed 19 OCT I(l) Hunted 20 OCT 1(1) Hunted 26 OCT I(1) Hunted 27 OCT I(2) Hunted 28 OCT 1(1) Hunted 5 NOV 0(2) Non-hunted 7 NOV 0(1) Non-hunted �487 Table 1.1 (cont.). Roost site locations of whooping cranes in the SLV during the 1987 stopover period. Bird Pat 6 Pat 9 Pat 16 Sex M M M Use Date Roost Complex (Site) 8 NOV 0(2) 8 NOV Last date observed Non-hunted 29 SEP C(1) Hunted 2 OCT A( 1) Non-hunted 3 OCT A( 1) Non-hunted 4 OCT A(2) Non-hunted 5 OCT A(1) Non-hunted 10 OCT . 0(2) Non-hunted 13 OCT 0(2) Non-hunted 18 OCT 8(1) Non-hunted 21 OCT A(1) Non-hunted 22 OCT A( 1) Non-hunted 25 OCT C( 4) Hunted 26 OCT 0(1) Non-hunted 27 OCT A(2) Non-hunted 30 OCT Last date observed 23 SEP C( 1) Hunted 25 SEP C( 1) Hunted 27 SEP 0(3) Non-hunted 5 OCT A(3) Non-hunted 8 OCT A(1) Non-hunted 9 OCT A(3) Non-hunted �488 Table 1.1 (cont.). Roost site locations of whooping cranes in the SLY during the 1987 fall stopover period. Bird Pat 16 Sex Oate Roost Complex (Site) Use M 13 OCT 0(1) Non-hunted 18 OCT B(l) Non-hunted 21 OCT A( 1) Non-hunted 31 OCT A(l) Non-hunted 1 NOV A(3} Non-hunted 3 NOV 0(1) Non-hunted 5 NOV O(l) Non-hunted 6 NOV 0(2} Non-hunted 10 NOV 0(2) Non-hunted 11 NOV 0(2) Non-hunted 12 NOV 0(2) Non-hunted 13 NOV O(2} Non-hunted 14 NOV 8(1) Non-hunted 15 NOV A(2) Non-hunted 16 NOV A(3) Non-hunted 16 NOV A(3) Non-hunted 17 NOV A(3) Non-hunted 18 NOV A(3) Non-hunted 19 NOV A(4) Non-hunted 20 NOV A(4) Non-hunted 21 NOV Last date observed �489 Table 1.1 (cont.). Roost site locations of whooping cranes in the SLV during the 1987 fall stopover period. Bird Sex Date Roost Complex (Site) Use 83-19 F 25 SEP C(2) Hunted 25 SEP C(4) Hunted 27 SEP C(4) Hunted 28 SEP C(2) Hunted 30 SEP C(2) Hunted 1 OCT C(2) Hunted 2 OCT C(1) Hunted 3 OCT C(2) Hunted 3 OCT 0(1) Non-hunted 4 OCT 0(2) Non-hunted 5 OCT C(2) Hunted 7 OCT C(2) Hunted 9 OCT 0(1) Non-hunted 13 OCT 0(2) Non-hunted 26 OCT H(I) Hunted 27 OCT 1(2) Hunted 28 OCT H(l) Hunted 3 NOV 86-15 F Last date observed 11 OCT F(1) Hunted 22 OCT 0(1) Non-hunted 29 OCT 0(2) Non-hunted 30 OCT 0(2) Non-hunted �490 Table 1.1 (cont.). Roost site locations of whooping cranes in the SLV during the 1987 fall stopover period. Bird Sex Date Roost Complex (Site) 86-15 F 5 NOV o (1) Non-hunted 6 NOV .0(2) Non-hunted 7 NOV 0(2) Non-hunted 10 NOV 0(2) Non-hunted 11 NOV Last date observed 87-5 Pat 3 F F Use 6 OCT O(l) Non-hunted 22 OCT O(l) Non-hunted 23 OCT 0(2) Non-hunted 30 OCT C( 4) Hunted 31 OCT 0(1) Non-hunted 1 NOV C( 4) Hunted 3 NOV Found dead by refuge personnel 9 OCT l(unknown) Hunted 10 OCT 0(1/2 ) Non-hunted 19 OCT 1(4) Hunted 20 OCT I(4) Hunted 28 OCT I(4) Hunted 29 OCT 1(9) Hunted 31 OCT 1(9) Hunted 1 NOV 1(6) Hunted 2 NOV 1(2) Hunted 8 NOV 1(6) Hunted �491 Table 1.1 (cont.). Roost site observations of whooping cranes in the SLV during the 1987 fall stopover period. Bird Pat 3 Pat 12 Pat 14 Pat 17 Sex Date Roost Complex (Site) Use F 9 NOV 1(2) Hunted 11 NOV 0.(2) Non-hunted 11 NOV Last date observed F F F 9 OCT 0(2) Non-hunted 21 OCT 0(2) Non-hunted 22 OCT 0(2) Non-hunted 5 NOV 0(1) Non-hunted 6 NOV 0(1) Non-hunted 7 NOV 0(1) Non-hunted 8 NOV Last date observed 11 OCT H(I) 11 OCT Last date observed Hunted 4 OCT 0(2) Non-hunted 6 OCT o ( 1) Non-hunted 9 OCT 0(1) Non-hunted 22 OCT 0(2) Non-hunted 25 OCT 0(2) Non-hunted 28 OCT 0(2) Non-hunted 30 OCT 0(2) Non-hunted 1 NOV 0(2) Non-hunted 4 NOV Last date observed �492 Table 1.2. Site fidelity for roosting complexes, roost sites within a roost complex, feeding sites, and loafing areas. Bird Roost Complexes Roost Sites Loafing Areas Feeding Sites Sites(Obs.) % Sites(Obs.) % Sites(Obs.) % Sites(Obs.) % 76-7 6(13) 46 8(13) 62 2(10) 20 22(55) 40 78-10 4(14) 29 5(14) 36 5(22) 27 22(56) 39 79-7 1(5) 20 3(5) 60 3(8) 38 10(27) 37 83-8 2(7) 29 3(7) 43 4(10) 40 12(29) 41 83-19 4 (15) 27 6(15) 40 9(22) 41 18(61) 30 86-15 2(9) 22 3(9) 33 8(9) 89 19(38) 50 Pat3 2(10) 20 ··5(10) 50 4(11) 36 15(51) 29 Pat4 2(12) 17 4(12) 33 5(13) ·38 14(40) 35 Pat6 3(8) 38 4(8) 50 3(17) 12 11(45) 24 Pat7 Pat9 3(3) 4(13) 31 7(13) 54 PatIO 100 3(15} 20 14(39) 36 2(2) 100 9(12} 75 16(22) 73 Patl2 1(5) 20 2(5} 40 6(9} 67 Pat14 1(1) 100 1(1) 100 2(2) 100 3(3) 100 2(2) 100 4(4) 100 Patl5 Patl6 4(25) 16 9(25) 36 10(25) Patl7 1(7) 14 2(7) 29 2(2) Totals 37(144) Means 62(144) 30 44 30(68) 44 100 18(33) 55 70(179) 48 240(586) 54 53 �493 Table 1.3. Hunted and non-hunted roost complexes used before and after opening day of hunting season. Roost Complexes Used1 Before hunting During hunting Bird Hunted Non-hunted 76-7 C H I B 0 78-10 F H 79-7 I I 83-8 C Pat4 Hunted Non-hunted Last Date Observed 0 4 Nov 0 13 Nov 4 Nov 0 10 Nov F I 0 8 Nov Pat6 I 0 8 Nov Pat9 C A 0 B Pat16 C A B D 83-19 C I 0 86-15 F 0 0 11 Nov Pat3 I D 0 11 Nov 0 D 8 Nov Pat12 Pat14 Patl7 0 30 Oct A B D 21 Nov 3 Nov H 11 Oct D D 4 Nov 1 Letters correspond to lettered roost complexes in figure 1. �494 of goose season and the second duck season occurred cranes using hunted roosting non-hunted roost complexes complexes on 31 October. before opening after opening day. Six day used only The 5 whooping cranes (83-8, Pat 16, 86-15, Pat 12, and Pat 17) using non-hunted roost complexes prior to opening day were unaffected by opening immediately day and remained continued in the non-hunted roosting complexes. to use hunted roost complexes Hunting pressure was not measured have been sufficiently H and I during opening hunting season. at these complexes, however, light that birds roosted undisturbed. 79-7 used roost sites II and 15 respectively, Following Three birds Pat 6 and prior to opening day. day these birds did not change roosting did change roost sites within a complex. and may Roost ~ites complexes but II and 15 were located at the outer edges of the complex and were also under different ownership than all other roost sites within this complex. pressure may have been greater on these 2 sites, thereby abandonment by roosting within 4 days following Sandhill All whooping Five whooping cranes causing left the SLV opening day. and whooping changed roosting 02. cranes. Hunting cranes remaining complexes and congregated cranes observed in the SLV after 9 November primarily on roosts 01 and from 9-13 November (78-10, Pat 3, Pat 6, and Pat 16) used these roosts even if they had not previously been observed crane at these sites. Pat 16 was the only remaining in the SLV along with several hundred sandhill November. bird roosted From 15 November in complex cranes until its departure A, also a non-hunted whooping after 13 on 21 November, area. this Roost sites 02 and A4 were kept open by pumped wells after other wetlands froze. �495 Eight whooping activity cranes periods within (22 observations) a day (Table 1.4). 24-hr cycle was 11,753 m (SE = 1142 m). between females and males same activity periods. and males for all distance feeding and evening distance 1.5). Sixty-five between percent flown between between areas and feeding roost and than morning sites f = were located When compared flown on days of RCLA use, AMRSFS distances NRCLA were used (Table 1.6; (Table All NRCLA were located of the MVNWR. 0.04). the were pooled over females Distances on NRCLA. the Rio Grande River, outside distances distance and evening were greater loafing all 5 flown in a of the loafing area observations on RCLA, with the remainder distances Mean distance distances comparisons. sites in both the morning during There was no difference in the inter-site Therefore, were located AMFSLA, south of with were greater PMLAFS, when and PMFSRS did not differ with NRCLA use. DISCUSSION Roost site selection investigated on 3 levels and biological another. cranes of the Grays Lake flock was (Fig. 1.4). characteristics level was site selection of suitable by whooping Level one examined of the roosting wetland. for a roosting roosting wetlands complex, the physical The second an area where occur within close proximity Level three was a landscape sites, loafing areas, and additional to one approach encompassing and second levels as well as the juxtaposition of suitable a number the first feeding roosting complexes. Roosting wetlands Habitat evaluations within the parameters Temple of the roosting of characteristics wetlands in the SLV fit well summarized by Johnson (1980) for roost sites used by the AWB population and of whooping �496 Table 1.4. Distances flown during complete diurnal cycles. Distance Flown (m) Bird Sex 78-10 M Date AMRSFS AMFSLA PMLAFS PMFSRS TOTAL 6 NOV 11 NOV 12 NOV 1545 7364 7455 1182 7727 636 1091 7515 636 1273 7455 7455 5091 30061 16182 X SE 17111 7223 79-7 M 2 NOV 7424 5030 7515 1394 21363 83-8 M 6 NOV 7333 364 4182 2848 14727 Pat 4 M 12 OCT 20 OCT 2182 2455 2303 2303 2303 2303 2455 2182 9243 9243 9243 0 10030 4981 Pat 6 M Pat 16 M 83-19 Pat 3 F F Combined 20 27 . 28 8 OCT OCT OCT NOV 2182 1333 2515 5697 485 485 485 6424 1303 485 1121 6424 1333 2515 909 6424 5303 4818 5030 24969 12 13 17 19 20 NOV NOV NOV NOV NOV 4667 8788 1697 1697 2030 4242 3606 152 2030 2121 4242 2333 152 2030 2121 4667 5242 1697 2030 2030 17818 19969 3698 7787 8302 11515 3134 3 OCT 4 OCT 28 OCT 3545 5333 2545 1879 2000 2485 1636 697 2515 3848 4424 1273 10908 12454 8818 10727 1054 29 OCT 2 NOV 9 NOV 939 5182 5273 1152 2970 6212 939 1909 2030 1364 4667 3030 4394 14728 16545 11889 3784 11753 1142 �497 Table 1.5. Comparisons of mean distances flown between consecutively used activity sites. Distance Mean Measured n (m) SE Ar~RSFS 13 4843 417 AMFSLA 16 2584 301 PMLAFS 14 2309 224 PMFSRS 15 4065 330 test of 'hypothesis that AMRSFS = AMFSLA 2 test of hypothesis that AMFSLA = PMLAFS 3 test of hypothesis that pr~LAFS= PMFSRS 4 test of hypothesis that PMFSRS = AMRSFS 0.00021 0.27062 0.00043 0.18164 �498 Table 1.6. Comparisons of distances between consecutive activity sites for days in which RCLA were used versus days in which NRCLA were used. Mean distance(SE) Inter-site distance Mean distance(SE) when RCLA were used n (m) when NRCLA were used n (m) ANRSFS 11 4080(538) 9 6255(853) 0.041 Ar~FSLA 15 2928(318) 13 2590(489) 0.252 pr~LAFS 13 2367(219) 11 2439(534) 0.973 PMFSRS 11 3064(458) 10 4745(731) 0.094 1 test of hypothesis that AMRSFS'for RCLA days = AMRSFS for NRCLA days 2 test of hypothesis that AMFSLA for RCLA days = AMFSLA for NRCLA days 3 test of hypothesis that PMLAFS for RCLA days PMLAFS for NRCLA days 4 test of hypothesis that PMFSRS for RCLA days = PMFSRS for NRCLA days �499 _---------aJ __ / ------/a2 LEVEL 3 I' LEVEL 1 , -, ~ Feeding site Roost site RCLA NRCLA Fig. 1.4. Three level approach of roost site selection. Levell is selection for a suitable roost site, level 2 selection for a roost complex, and level 3 is for selection based on juxtaposition of all required habitats. Distances al and a2 are flown by birds using RCLA, distances bl and b2 are flown by birds using NRCLA. �500 cranes. Shallow water and extensive horizontal visibility appear to be the most consistent characteristics among wetlands used by roosting cranes. Two variables measured in the SLV which were not consistent with site evaluations in the Central Flyway included distance from roost site to potential hazards and distance to disturbance . .Power line strikes account for 39% of all known losses of fledged birds in the cross-fostered whooping cranes (unpubl. data, Id. Coop Wildl. Res. Unit). In the SLV, agricultural fields are primarily irrigated by center pivot overhead sprinklers. transmission Recently, large power and distribution lines have been constructed to service the expansion of these systems (Brown et al. 1987). Many power lines cross traditional crane concentration areas. Roost sites are frequently closer to such hazards than sites used by AWB whooping cranes, but cranes in the SLV are not selecting against areas where these hazards exist. This may be a result of unavailability of areas free from these hazards or a lack of recognition of such threats by the birds. Whooping cranes are by nature wary and prefer to avoid human activity (Allen 1952). developments Roost sites are usually away from human such as roads, houses, and buildings. This isolation distance may vary in relation to level of activity associated with the development and visual isolation of the roost from the development. Whooping cranes of the Rocky Mountain population have become more habituated to human disturbance than the AWB population because of greater accessability of breeding, stopover, and wintering grounds (J. C. Lewis, pers. commun.). This is consistent with my observation that distance to potential disturbances were less in the SLV when compared �501 to AWB crane 'roost sites. Three roosting adjacent to roads. adjacent to roads, were visible from roads. explanation for the decreased difference stopover The majority complexes in familiarity of the remaining isolation appear as a potential of SLV roost sites may be the allowing birds to roost at whooping cranes were not from roads or houses and were more consistent described for the AWB flock (see chapter isolation of roost sites might result from additional overriding the necessity Naturally-reared and sometimes Howe 1987). 3). whooping cranes generally behavior additional flock that isolation migrate vigilance from disturbance site was greater than alert behavior and Derrickson whooping 1981, cranes sandhill crane Alert crane at a non-traditional documented flock in the SLV (see chapter for the same 2). Complexes Selection for roost sites in close proximity wetlands for cranes Temple as pairs, families, may not be as critical. stopover roosting disturbance. by a surrounding of a cross-fostered bird among a sandhill whooping decreased flock vigilance of Rocky Mountain behavior Roosting Alternativ~ly, small groups (Allen 1952, Erickson enough with roost sites to avoid areas of potential The gregarious may provide What may Roost sites used at 2 non-traditional sites by solitary cross-fostered visible The SLV is a traditional such as a road or house, may have proven over the years not to be a threat, stopover possible cranes each spring and fall. disturbance, these sites undisturbed. sites, although not Another with roost areas. site, used by migrating in the Valley were was observed were described (1983), in the SLV. to other suitable Similar roosting complexes by Lovvorn and Kirkpatrick and Littlefield (1986). Such complexes (1982), Melvin and potentially �502 provide several advantages over single roost sites. For example, cranes fly to roost approximately one half hour after sunset, allowing limited time to select a roost. If a bird approaches a roost site that appears disturbed, an alternate roost can be quickly selected. On several occasions I observed that the presence of humans at a roosting wetland caused birds to fly over the site and select a nearby undisturbed roost. Roosting complexes also provide an efficient escape if birds are disturbed off a roost after landing. Birds flushed from roosts flew to nearby roost sites within the same roosting complex. Disturbance by hunters affected the distribution of whooping cranes in the SLV and may have accelerated their migration chronology. The effect of hunting was documented by observing changes in roost complex use before and after opening of hunting season. Cranes usually abandoned hunted roost sites, switching to non-hunted roost complexes or low-pressure hunted complexes. Abandonment of hunted roost areas following opening of hunting season has been well documented for sandhill cranes (Lovvorn and Kirkpatrick 1981, Melvin and Temple 1983, Littlefield 1986). During fall 1987, roost area use before hunting consisted of 9 roosting complexes (five hunted complexes, and 4 nonhunted complexes). During hunting season only 2 hunted roost complexes were used by whooping cranes. Hunting pressure was not measured at hunted areas, so it is possible that the 2 hunted roost complexes used following opening day had minimal hunting pressure. A smaller scale response was observed in 2 whooping cranes abandoning roost sites within a hunted complex and switching to other non-hunted roosts within the same complex. The roost sites used prior to hunting were located at the outer edges of the complex and were also under different �503 ownership than all other roost sites within this complex. pressure may have varied sufficiently portion of the area was unsuitable responded to hunting by leaving wintering grounds. migration (Stahlecker Landscape scale Juxtaposition foraging (Caccamise describes Other factors, however, also affect the chronology of required habitats, also influences cranes. center (Weatherhead and Morrison 1986). insight components sites, communal by 3 (2) two- which hypothesis best sites are related for a particular important in roost selection. among roost sites, feeding sites, cranes in the SLY using inter-site Roost sites, and frequently to all daily activities been explained Understanding spatial relationships of the roosting between (Ward and Zahavi 1973), into factors and loafing areas for whooping distances. Relationships feeding 1983), and (3) patch-sitting how roosts and foraging I described of crane of roost sites, have most frequently (1) information species provides such as the third level of selection areas by whooping principal-strategies on opening 1986). and roosting hypotheses: on to the 9 days, and after the 11th day all females and food abundance and loafing Cranes may also have the SLY and continuing and 71% of the males were gone. investigation, for roosting. that only a Nine of 14 (64%) whooping cranes present day left the Valley within weather within the complex Hunting complexes. loafing areas, were considered Roosting complexes when time at roost and loafing were central areas were combined. Caccamise and Morrison (1988) describe these central locations for communal starlings (Sturnus vulaaris) as diurnal centers. A second type of habitat used by starlings activity was described as �504 supplemental feeding areas; patches of readily accessible.high energy food located outside the diurnal activity center. Caccamise and Morrison (1988) hypothesized that roosts form near locally superabundant food patches (patch-sitting). By estimating habitat type fidelity (diurnal activity center-based birds versus roost-based birds) and measuring distances flown between the diurnal activity center, roosts, and supplemental feeding areas, they were able to support this hypothesis. I applied this methodology to whooping cranes in the SLY and found evidence that cranes are roost-based birds. Roost site selection is then influenced by the fact that the roost is the center of operation of all daily activities at the stopover site. Factors such as minimal disturbance and distance to supplemental feeding areas should therefore affect suitability of the roosting wetland. The first criteria for establishing cranes as roost-based birds is that greater site fidelity is exhibited for roosting complexes than any other activity sites. Two factors affected site fidelity: and the numbers of cranes in the Valley. hunting, Cranes remaining in the SLV after 9 November congregated at 2 non-hunted roost complexes. Inter-site distances also supported the roost-based hypothesis. The primary activities of the cranes during roosting and loafing are alert and comfort behaviors (R. C. Drewien, Prog. Rep. Whooping Crane Egg Transplant Experiment 1-20). Although whooping cranes feed on a variety of invertebrates and aquatic plants at wetland sites while roosting and loafing, agricultural lands, primarily fields containing small grains, comprise over 70% of the sites where feeding is the primary activity (Johnson and Temple 1980). These agricultural sites, used during morning and evening feeding periods, are supplemental �505 feeding areas as described generally returned and evening feeding in the inter-site are used for minimizing feeding and Morrison to the same or adjacent for both the morning Patterns by Caccamise distance and Benham 1976, Reinecke data suggest to a nearby supplemental to loaf (Fig. 1.4). to select 1986). for whooping and Kirkpatrick The first strategy of cranes cranes (Lewis 1982, Krapu et is for cranes to fly feeding area then return to the roost complex With this strategy it is advantageous loafing habitat. The second strategy loafing areas by cranes feeding at distant allowing a bird to use a distant feeding used by whooping that 2 strategies The close proximity roost sites within roost complexes in returning feeding area 1981) and for sandhill and Krapu 1979, Lovvorn Cranes periods. daily movements. 1969, Kauffeld al. 1984, Littlefield energy supplemental sites to roost sites has been documented (Shields (1988). for cranes that also provide suitable involves use of non-roost feeding complex sites, thereby site but not expend extra / to the roost complex to loaf. Both strategies cranes using the same roost complex. apparently do not select a roost site in preference but rather select a site that affords the opportunity were Thus, cranes of one strategy, to employ either strategy. The use of NRCLA was only observed may have resulted areas. converted south of the river area. from the effects of different In the vicinity of the Rio Grande agricultural nearby feeding areas. land use in the 2 River more land has been to grain fields, thereby providing fewer loafing This more feeding sites but The area south of the river is also primarily but is interspersed with non-agriculturai land. sites are not limited south of the river, the Although �506 availability of suitable loafing habitat outside the roost complexes provides cranes with the opportunity to exploit distant feeding sites at no increased cost. Roost site selection by whooping cranes of the cross-fostered appears dependent characteristics flock not only on the physical and biological of a roosting wetland but also on the juxtaposition of other suitable roost sites, feeding sites, and loafing areas. Further studies should be conducted which relate the role of suitable loafing habitat aut-s-ideof roost complexes to the use of feeding sites. The influence of suitable loafing habitat adjacent to roost sites should also be investigated as a factor in roost site selection. L-ITERATURE CITED Allen, R. P. 1952. 3. 246pp. The whooping crane. Natl. Audubon Soc., Res. Rep. Anderson, D. R. 1965. Effects of water manipulation on waterfowl production and habitat. M. S. Thesis, Colo. State Univ., Fort Collins. 60 pp. Archibald, G. W., J. Baldwin, and P. Konrad. 1976. Is sandhill hunting a threat to whooping cranes? Pages 207-222 in J. C. Lewis, ed. Proc. Int. Crane Workshop. Okla. State Univ. Publ. and Print., Stillwater. Brown, W. M., R. C. Drewien, and E. G. Bizeau. 1987. Mortality of cranes and waterfowl from power line collisions in the San Luis Valley, Colorado. Pages 128-136 in J. C. Lewis, ed. Proc. 1985 Crane Workshop. Natl. Audubon Soc. Tavernier, Fl. Caccamise, D. F. and D. W. Morrison. 1986. Avian communal roosting: implications of diurnal activity centers. Am. Nat. 128:191-198. __ , and _ . 1988. Avi an communal roost ing: a test of the "patch-sitting" hypothesis. Condor 90:453-458. Drewien, R. C. 1973. Ecology of Rocky Mountain greater sandhill cranes. PhD. dissertation, Univ. Idaho, Moscow. 152 pp. , and E. G. Bizeau. 1974. Status and distribution of greater --sandhi 11 cranes in the Rocky Mountains. J. Wi 1dl. 11anage. 38: 720742. �507 , and 1978. Cross-fostering whooping cranes to sandhill crane foster parents. Pages 201-222 in S. A. Temple, ed. Endangered birds: management techniques for preserving threatened species. Univ. Wisconsin Press, Madison. Ellis, S. L., T. G. Shoemaker, H. Wen Shen, and W. Wang. Niobrara River whooping crane habitat study. Prepared Environmental Research and Technology, Inc. for Water Resour. Serv., U. S. Dep. Interior, Denver, Colorado. 1981. by and Power 356pp. Erickson, R. C. and S. R. Derrickson. 1981. The whooping crane. Pages 104-118 in J. C. Lewis, ed., Cr-ane research around the worl d, Int. Crane Foundation. Int. Counc. for bird preservation. Baraboo, WI. Hopper, R. M. 1968. Publ. 22. 88pp. Wetlands of Colorado. Colo. Div. Wildl. Tech. Howe, M. 1987. Habitat use by migrating whooping cranes in the Aransas -Wood Buffalo corri dor. Pages 303 -311 in J. C. l.ewis , ed., Proc. 1985 Crane WorkshQP. Natl. Audubon Soc., Tavernier, Fl. Johnson, K. A. and S. A. Temple. 1980. The migratory ecology of the whooping crane. Unpublished report, contract 14-16~009-78-034, U. S. Fish and Wildl. Serv., Washington, D. C. 120pp. Kauffeld, J. D. 1981. Management of migratory crane habitat on Alamosa and Monte Vista National Wildlife Refuges. Pages 117-121 in J. C. Lewis, ed. Proc. 1981 Crane Workshop. Natl. Audubon Soc., Tavernier, Fl. Krapu, G. L., D. E. Facey, E. K. Fritzell, and D. H. Johnson. 1984. Habitat use by migrant sandhill cranes in Nebraska. J. Wildl. Manage. 48:407-417. Lewis, J. C. 1976. Roost habitat and roosting behavior of sandhill cranes. Pages 93-104 in J. C. Lewis, ed. Proc. Int. Crane Workshop. Okla. State Univ. Publ. and Print, Stillwater. Lingle, G. R., P. J. Currier, and K. L. Lingle. 1984. Physical characteristics of a whooping crane roost site on the Platte River, Hall County, Nebraska. Prairie Nat. 16:39-44. Lingle, G. R. 1987. Status of whooping crane migration habitat within the Great Plains of North America. Pages 331-340 in J. C. Lewis, ed. Proc. 1985 Crane Workshop. Natl. Audubon Soc., Tavernier, Fl. Lingle, G. R., G. A. Wingfield, and J. W. Ziewitz. 1988. The migration ecology of whooping cranes in Nebraska, U. S. A .. Proc. Int. Crane Workshop (in press). Littlefield, C. D. 1986. Autumn sandhill crane habitat use in southeast Oregon. Wilson Bull. 98:131-137. �508 Lovvorn, J. R., and C. M. Kirkpatrick. 1981. Roosting behavior and habitat of migrant greater sandhill cranes. J. Wildl. Manage. 45:842-857. , and 1982. Field use by staging eastern greater sandhill --cranes.-J-.-Wildl. 11anage. 46:99-108. Melvin, S. M., and S. A. Temple. 1982. Migration ecology of sandhill cranes: a review. Pages 73-87 in J. C. Lewis, ed., Proc. 1981 Crane Workshop. , and 1983. Fall migration and mortality of Interlake, ---~Manitoba sandhill cranes in North Dakota. J. Wildl. Manage. 47:805-817. Melvin, S. M., R. C. Drewien, S. A. Temple, and E. G. Bizeau. 1983. Leg-band attachment of radio transmitters for large birds. Wildl. Soc. Bull. 11:282-285. Nudds, T. D. 1977. Quantifying the vegetative structure of wildlife cover. Wildl. Soc. Bull. 5:113-117 Reinecke, K. J., and G. L. Krapu. 1979. Spring food habits of sandhill cranes in Nebraska. Pages 13-19 in J. C. Lewis, ed. Proc. 1978 Crane Workshop. Colo. State Univ., Fort Collins. Ryder, R. A. 1951. Waterfowl production in the San Luis Valley, Colorado. 11. S. Thesis, Colo. A & M Col1., Fort Collins, 166pp. Shields, R. H., and E. L. Benham. 1969. Farm crops as food supplements for whooping cranes. J. Wild1. Manage. 33:811-817. Stahlecker, D. W. 1986. The 1985 fall crane migration in the Rio Grande Valley, New Mexico. Unpub1. Rep., New Mexico Audubon Soc., Albuquerque. 22pp. Ward, J. P. and S. H. Anderson. 1987. Roost site use versus preference by two migrating whooping cranes. Pages 283-288 in J. C. Lewis, ed., Proc. 1985 Crane Workshop. Ward, P. and A. Zahavi. 1973. The importance of certain assemblages of birds as "information centers" for food finding. Ibis 115:517534. Weatherhead, P. J. 1983. Two principal strategies in avian communal roosts. Am. Nat. 121:237-243. Whooping Crane Recovery Team. 1980. Whooping crane recovery plan. U. S. Dep. Inter., Fish and Wi1d1. Serv., Nebr. Game and Parks Comm., Texas Parks and Wildl. Dep.; Natl. Audubon Soc. 206pp. �Table AI. Habitat evaluations Luis Valley, Colorado. Hoosl [liH!!!!re Complex Size (S ite) (ha) --.. _._- ._------_ .... !!Q!!~g for 35 roosting wetlands located during fall 1986 and 1987 in the San tQ_IJQtlli.!U!!LiU~lllrbance llQM! fillllsLim (III) . _-_._-_. Specific Couduc t iv i t.y of Water Oist~nce to HQlenlliLh!!I!!rd (mmhos/cm) ._-_ .. __ . _ .._. _ .. __ - ._---_ POI'JerLine Fence (m) .. _.-- --------- A (1) 1.5 1470 72 092 1300 50 50 A(2) 1.5 944 208 922 600 192 192 -u -u A(3) 5.3 862 244 862 750 236 236 I-< ::t:> rn :z: 0 >< A(4) 8.4 504 226 468 600 222 222 13 ( I ) ]2.3 1424 15 1394 1600 485 485 [3(2) 11.0 909 970 423 975 0 970 C (1) 0.4 1273 394 1273 500 394 394 C(2) 0.2 136,1 333 1333 700 242 333 C(3) 0.6 1515 606 1405 600 0 606 C(4) 78. ] 1152 000 ))52 950 194 800 o(]) 58.2 1181 1)21 ]10) 950 0 1121 0(2) 73.4 939 800 939 460 34 800 0(3) 60.9 1333 24 1303 950 0 24 ::t:> I.Jl 0 1.0 �Table Al (cont.). Habitat evaluations San Luis Valley, Colorado. for 35 roosting wetlands located during fall 1986 and 1987 in the ---------- Roost Qistilnce tQ_Qote!lJial disturbance Complex Size (Site) (ha) l!Q!!~~ BQ_Q1 ~!!U1Ins of Hater Distance to potential hazard EOI'/erLi ne Fence (mmhos/crn) (III ) -_. Specific Conductivity (m) __ ------ E (1) 19.5 970 1121 606 > 10000 0 56 E(2) 27.4 940 112 j SIS > 10000 24 303 .[(3) - 1879 175n 1303 750 152 1091 r( ] } 2.7 121 174 56 950 44 174 F(2) 0.9 78 0 64 580 3 9 F(3} - 264 9 254 600 0 0 ]1.2 592 624 532 2600 2 624 G(2} 1.4 1126 2613 242 2000 90 268 G(3) 3.3 1350 42 188 II( 1) 9.6 456 574 420 560 3 828 11(2) 0.6 610 588 578 800 152 588 I(1) 1.6 1148 1000 848 680 ·0 658 1(2 ) 3.5 1242 455 727 500 273 697 G(l) W81 284 Vl I-' 0 �Table Al (cont.). Habitat evaluations San Luis Valley, Colorado. for 35 roosting wetlands located during fall 1986 and 1987 in the --------- Roost --- ni~ti)!1~g_tQ.__nQt~nttel ~U~1.!1rhanc~ Specific Conductivity Complex Size (Site) (ha) !hl!J~g fll2.i!.d fluiJging ([II) of I-I a tel' Oii1~nce tQ_p.ote!1tial_b~~Ar~ Fence Power Line (01) (1IIIIII1os/elll) --1(3) 0.2 758 788 697 3500 4 333 1(4 ) 9.3 424 455 424 . 650 71 424 1(5) 1.2 424 242 242 2200 0 242 1(6 ) 1.2 1485 152 333 600 0 394 1(7) 2.5 1758 182 576 480 0 576 I(8) 0.1 814 8GO 830 600 0 504 I(9) 5.3 333 2 303 5000 0 0 1(10) 0.04 212 182 70 2400 27 68 8.6 2515 2212 2303 800 16 2212 Alamosa _._------_. l.r1 I-' I-' ��513 CHAPTER 2 WHOOPING CRANE BEHAVIOR AT TRADITIONAL AND NON-TRADITIONAL FALL MIGRATION STOPOVER SITES SUMMARY Behavior described at a non-traditional stopover -located of a female subadult whooping stopover crane (Grus americana) site (NTSS) and a traditional site (TSS) during the 1986 fall migration. in eastern Colorado using a TSS on the Alamosa Luis Valley alert behavior Wildl~fe Daily activity Refuge and foraging to behavior patterns (NWR) in the San eastern Colorado. feeding periods increased at the NTSS compared at the TSS. time decreased Time budget activity periods The frequency of when feeding alone when feeding with a flock at the TSS. at the NTSS were consistent with those of the cranes of the Grays Lake flock using TSS. One result experiment National path of The same bird was observed on this crane during all diurnal at the NTSS, and during whooping crane flock. 6 days after it departured data were collected The NTSS was 170 km east of the u$ual migration the Grays Lake heterospecific was of the whooping is the communal during migration. Sandhill their large migration crane transplant behavior cranes and foster parent of Grays Lake whooping cranes (Grus canadensis) flocks and communal along the Platte and North Platte Rivers behavior are well known for at staging (Krapu 1979, Johnson areas and �514 Temple 1980, U.S. Fish and Wildlife Service 1981, Melvin and Temple 1982, Krapu et al. 1984, Currier and Ziewitz 1987, Lingle et al. 1988). Whooping cranes of the natural Aransas-Wood Buffalo population, however, migrate as individuals or in family units (Allen 1952, Erickson and Derrickson 1981, Howe 1987). The use of 2 non-traditional migration stopover sites (NTSS) during fall 1985 by solitary subadult whooping cranes of the Grays Lake flock, and the repeated use of a site near Hudson, Colorado (spring 1986, fall 1986), shows that fosterreared whooping cranes have the ability to survive as solitary birds despite rearing by gregarious foster parents. The opportunity to observe the behavior of the same bird while alone at the NTSS and as a member of a sandhill flock at the traditional stopover site (TSS) in the San Luis Valley (SLV) could provide insight into any behavioral changes accompanying the presence or absence of a surrounding ftock. The effect of flock size on vigilant behavior of individual birds within the flock has been investigated in numerous studies (Powell 1974, Abramson 1979, Barnard 1980, Bertram 1980, Weatherhead primary assumption 1983). A of these studies is that vigilance while feeding enhances the probability of detecting predators. Waite (1987), however, found evidence supporting the hypotheses that vigilance is predator- and conspecific-directed and is influenced both by the tendency to be social and by an individual's dominance status within the social group. Subordinate social foragers have the additional constraint on their foraging time of keeping higher-ranking under surveillance. flock mates Knight and Knight (1986) also provided evidence that vigilance behavior of birds that feed in social groups has the additional function of conspecific surveillance. �515 Biologists studying whooping cranes of the Grays Lake flock have noted a low level of alert behavior during daily activities compared to sandhill cranes of the same flock (R. C. Drewien, pers. commun.). Drewien hypothesized that this may result from a possible learning deficiency as a consequence of rearing by the foster greater sandhill parents. He felt that the whooping cranes were displaying behavior. chick-like This behavior could increase the possibility of predation because of decreased vigilance for predator protection (Tacha 1981). An alt~rrative hypothesis is that the whooping cranes are displaying dominant behavior within the flock and, as suggested by Waite (1987), exhibit decreased vigilance because of social status. Data were collected on an individual whooping crane with and without a surrounding sandhill flock to address these hypotheses.' STUDY AREA The NTSS was located 2 km south of Hudson, Colorado in southern Weld County. m. Topography is broadly rolling with an elevation of 1512 Irrigated farmland in the area supports the main crops of corn, alfalfa, wheat, and sugar beets. grown in lesser amounts. Malting barley and vegetables are Feeding sites used by subadult, female whooping crane #8422 were nearby fields of volunteer barley, corn, wheat, hay, and grazed pasture. as (system) palustrine, (class) emergent wetland, and (modifier) saturated/semi-permanent/seasonal 1979). The roosting wetlands were classified wetlands (PEMY; Cowardin et al. Both roost sites were located in grazed cattle pastures. Loafing areas were adjacent to the roosting wetlands. The TSS was located on the Alamosa NWR 1.9 km southeast of Alamosa, Colorado. The 4520-ha refuge is composed of natural riverbottom �516 wetland and ;s bordered on the west by the Rio Grande River. The feeding site used by #8422 was a cut barley field on the northwest corner of the refuge. greasewood Loafing areas were river bottomland and a (Sarcobatus vermiculatis) area of the refuge. The roosting wetland was a flooded slough maintained by an artesian well. METHODS Activities of bird #8422 were recorded at IS-second intervals following the protocol of focal-animal sampling (Altmann 1974). Bird #8422 was identified by a combination of colored leg bands (red band left leg, white band right leg) and a radio attached to the left leg band (R. C. Drewien, pers. commun.). Behaviors were classified 'according to the codes developed for sandhill and whooping cranes of the Grays Lake flock (R. C. Drewien, pers. commun.), coded numerically, (see Table 2.I) then recorded on data sheets. Observations were performed with a 30x spotting scope between dawn and dusk. observations were not made because the primary nocturnal activity of cranes is sleeping (R. C. Drewien, pers. commun.). corresponds Night-time This methodology to that used by W. M. Brown and R. C. Drewien for cranes of the Grays Lake flock. Time budget data were summarized by days and grouped into 9 general catagories of behavior: (1) feeding, (2) drinking, (3) alert, (4) resting, (S) comfort, (6) locomotion, and (9) out of sight. (7) agonistic, (8) vocalization, Each day of observation was divided into 5 activity periods: (1) a.m. roost, (2) a.m. feeding, (3) loafing, (4) p.m. feeding, and (5) p.m. roost. The number of behavioral codes recorded for each activity was divided by the total number of recordings during that activity period �517 Table 2.1. Code 01-09 01 02 03 lQ 11 12 13 14 15 16 17 18 19 Coded behaviors used in time budget data collection. Activity stop observation out of sight out of sight in standing Foraging corn alfalfa milo barley wetland natural upland plowed/disced field picking up gravel other Code 60 66 67 66 68 69 69 70 70 71 72 72 73 74 20 Drinkina 75 30 Defecation 76 77 40 'Standing (Alert) standing alert (tall alert) standing 1 leg (head horizontal) head down-looking/hunting standing upright, wings outstretched 41 42 43 44 50 51 52 53 54 55 60 61 62 62 62 63 64 65 ("'- 00 78 80 81 82 83 84 85 Restina/Sleepina/Loafina head tuck position standing on 1 leg (head down) bill tucked under wing laying/sitting down other 86 Comfort Movements oil i ng head rubbing head shake (neck/head fl i ck) head stretch (neck and head) scratching bathing wing flapping stretching-leg extended 92 87 88 90 91 93 94 95 96 97 Activity Comfort Movements stretching-wings over back, head and neck extended shaking-body preening preening radio thermoregulation (bill gape) yawning Locomotion hunting (head down) walking running running with wings outspread flight intention flyi ng 1 andi ng jumping/dancing aerial pursuit (chasing sandhills) butterfly Agonistic Behavior (Initiates, recipient=circle #) threat posture aggressive strut (stick walk) attacking (charging) pecks other bird is being pecked submissive behavior (avoidance=retreat, runs or backs away, head tuck) fighting - jumps in air other Call s nervous call (Kepler) guard/ alarm call unison call whistle-click (contact, distress, contentment) threat call precopulatory other �518 to obtain percentage of time spent per activity per period. small sample sizes (non-traditional site N=9, traditional Because of site N=4), Wilcoxon tests were used to detect differences in behavior between TSS and NTSS. RESULTS The daily activity pattern of #8422 at both the NTSS and TSS (Table 2.2) was similar to that observed in other whooping cranes of the Grays Lake flock during fall stopover periods at TSS in the SLV (Drewien 1982, Drewien and Brown 1983, 1984). This general daily activity pattern is to fly from the roost just prior to sunrise to the morning feeding site, where they remain until late morning or early afternoon, after which they fly to a loafing area. Cranes remain in the loafing area until late afternoon then fly to a feeding site (usually the same location used in the morning)· until just prior to sunset when they return to the roost where they remain through the night. The location category "other" includes observations of flight and at sites visited for a brief time between activity periods or following a flush. Whooping crane #8422 was first observed near Hudson, Colorado on 17 October. Daily behavioral observations began on 18 October and continued through 26 October, when I observed the bird spiral and leave the area. During the 9-day stopover period near Hudson, 45.7 hr of time budget data were collected: 1.5 hr at the a.m. roost site, 22.6 hr at the a.m. feeding site, 9.5 hr at the loafing site, 6.3 hr at the p.m. feeding site, 5.2 hr at the p.m. roost site and, 0.6 hr at other sites (Table 2.3). Daily summaries of time spent in diurnal activities are presented in Appendix B. �519 Table 2.2. Locations and activities of whooping crane #8422 during the 1986 fall stopover period in Colorado. Date Time Location1 17 Oct 1200 RS1, FS1 18 Oct 1205 1205-1841 FS1 RSl, FSI 19 Oct 20 Oct 21 Oct 22 Oct 23 Oct 24 Oct 700 715 RS1 RS1 1100 1309 1300 FS2 FS2 FSI 1552 1751 FS2 RSI 700 730 1049 RS1 FS2 FSI 1448 1539 1138 708 735 1110 1200 1526 1620 1812 1840 RS1 FS1 FS2 RS1 FS2 FS1 RS1 RSI FS2 FS2 RS1 1923 1943 1603 1617 1656 1703 RS1 FS2 FS2 WI WI W2 801 815 1225 1323 1425 FS7 FS7 FS1 FSI Activity #8422 first observed by landowner L. Long, reported to CDOW begin observation loafed and foraged in the area surrounding the roost site, fed in an adjacent hay field and volunteer wheat field begin observation flew from the roost in heavy fog, I was unable to locate for 4 hrs foraged in volunteer barley flew from the area foraged in volunteer wheat near wetland edge, loafed flew to feeding site flew to roost site, stop observation begin observation flew to feeding site flew to volunteer wheat, loafed and foraged in water stop observation foraging begin observation flew to feeding site flew to volunteer wheat field in water and surrounding area flew, not located for 45 min. located at feeding site flew to RSl, stop observation begin observation, too foggy to collect time budget data flew to feeding site located at feeding site hazed from the area by a dog located at Spayds' pond flew to SW end of Longs' pond 1 located on N side of Longs' pond 1, stop observation begin observation, seen flying from direction of Longs' pond 2 located in grazed pasture flew to RS1 located in volunteer wheat hazed by 2 dogs, flew to Longs' pond 2 �520 Table 2.2 (cont.). Locations and activities of whooping crane #8422 during the 1986 fall stopover period in Colorado. Date Time 24 Oct 25 Oct 26 Oct 1521 RS2 1842 1843 721 740 1038 1406 1619 RS2 RS2 RS2 FS2 FS2 RS1, FS1 RS2, FS7 1843 919 1140 RS2 FS2 FS2 2 Nov 3 Nov 4 Nov 5 Nov 6 Nov 1 Location FS 753 1306 1622 1650 1857 842 925 1040 1501 1713 1930 1046 1519 1716 837 916 1508 1716 FS FS FS FS FS LS LS FS FS FS FS FS FS FS FS FS FS FS Activity in and near edge of the water, foraged in grazed pasture stop observation begin observation flew towards feeding site located at feeding site f1ew towards RS1 located bird foragins in water and adjacent pasture stop observation begin observation observed spiralling and leaving Hudson area, stop observation first observed by Alamosa NWR personnel foraging in a barley field with a group of sandhill cranes and 1 adult whooping crane begin observation flushed from FS begin observation Flew to roost begin observation flew to adjacent greasewood area flew back to FS flew from feeding area begin observation flew to roost bird arrived at FS flew in SW direction begin observation flew to roost begin observation all birds flushed from area begin observation flew to roost RS1-roost site on Wilhelm property, used in previous stopovers FSl-volunteer wheat field adjacent to RSI FS2-volunteer barley field NE of RS1 WI-pond located SE of RSI on Spayd property W2-pond located SE of RS1 on Long property RS2-roost site located on Long property SE of RS1 FS7-grazed pasture adjacent to RS2 FS-barley field on Alamosa NWR LS-greasewood field adjacent to feeding site �Table 2.3. Average percent time spent in various diurnal activities by whooping crane #8422 from 18-26 October 1986 near Hudson, Colorado. Activities were recorded at IS-second intervals. Locatioll Ac tivity A.M~QQ~t ~ (SD) _._------_---_-------- --- Feeding 4.0 (7.4) Drillking 0.0 (-) Alert Comfort I OCOIIIO 0.0 10.7 t ion - x (SO) 8.3 (8.5) 0.0 (-) 0.) (0.1) 47.6 (7.3) (-) 0.0 (-) (13.3) 1.0 (1.2) - ) 62.0 (18.0) 0.1 IS.7 (5.3) 0.0 Vocal i z at ion 0.0 (- 0.0 1.1 (1.2) 0.7 of Sight ~ (9.1) 26.7 (12.2) 32.0 Agonistic Out (SO) £_J'L __f g e <1iu s Loafing - x (SO) --------- 54.6 (IS.8) Re s t i119 8_,_!L_I eed j us 0.0 (0.3) 16.1 (12.6) 12.8 (9.4) 0.0 (- (0.6) ) - ) tJ_L_BQQ~t - (SO) x QttJer ~ (SO) TolQl - -- ---------- 33.2 (21.8) 0.0 ( - ) 39.9 (2. I) ------ 1.7 (1.6) 1.4 0.5 (1.0) 0.7 (24.9) 40.4 (1.7) 0.0 63.8 1.3 (SO) X 25.7 (10.9) 0.0 (0.1) 49.9 (7.0) - 0.2 (0.4) 11.6 - 6.1 (4.8) 45.9 - 17.0 - 0.0 (-) 5.2 (9.2) 20.0 (9.5) 9.8 (9.2) 0.0 {- 0.0 (- 0.0 - 0.0 (- 0.0 - 0.0 0.0 - 1.0 21.5 (16.1) 0.0 (- 0.0 (- 0.0 0.6 (0.8) 1.8 (2_9) 1.4 (2.5) (5.8) (- ) (0.9) Vl N f-' �522 Alert behavior accounted for the majority of the bird's activity during 8 of the 9 days of observation. On the day that did not follow this pattern, the percent time spent in alert behavior tied with feeding as the primary activity. When days were divided into the 5 100% of the loafing observations, 50% of the p.m. feeding site observations and, 100% of the p.m. roost site observations. Feeding accounted for the second highest percent of diurnal activity, locomotion followed feeding, and comfort behaviors ranked fourth for total daily activities. The majority of comfort behaviors occurred at roost sites and loafing areas. Whooping crane #8422 was observed in the SLY from 2-8 November, and daily behavioral observations November. on this crane were conducted from 3-6 During the SLY stopover period, I observed this bird a total of 16.8 hr: feeding site. 10.4 hr at the a.m. feeding site and 6.4 hr at the p.m. Daily summaries of time spent in diurnal activities during the San Luis Valley stopover period are presented in Appendix C; average percent time spent in these activities are presented in Table 2.4. Time budget data were collected only during the a.m. and p.m. feeding periods, since approaching the birds to collect behavioral data at the roost site and loafing area might have caused the birds to flush. For 87% of all observations, the primary activity during the a.m. and p.m. foraging periods was feeding, followed by alert behavior, then locomotion. This time allocation is consistent with that observed in other whooping cranes of the Grays Lake flock during a traditional stopover period in the SLY (Drewien 1982, Drewien and Brown 1983, 1984). Behavioral data recorded by W. Brown and R. Drewien on other �523 Table 2.4. Average percent time spent in various diurnal activities by whooping crane #8422 from 3-6 November 1986 in the San Luis Valley, Colorado. Activities were recorded at IS-second intervals. Activity A. M. Feeding P. M. Feeding SD SD SD (%) (%) (%) Total Feeding 74.6 9.5 78.7 1.0 72.8 3.7 Drinking 0.0 0.0 0.0 0.0 0.0 0.0 17.0 2.5 11.1 1.4 15.2 3.2 Resting 0.0 0.0 0.0 0.0 0.0 0.0 Comfort 2.5 2.8 0.2 0.5 1.6 1.7 Locomotion 9.9 1.6 10.0 2.4 10.3 0 ..7 Agonistic 0.0 0.0 0.0 0.0 0.0 0.0 Alert , Vocalization 0.0 0.0 0.0 0.0 0.0 0.0 Out of Sight 0.3 0.2 0.0 0.0 0.2 0.1 �524 whooping cranes in the San Luis Valley were not available for statistical comparison. The behavior of whooping crane #8422 during both feeding activity periods at the Hudson stopover site differed (E < 0.05) from the behavior exhibited by the same bird in the corresponding activity periods at the TSS in the SLY (Table 2.5). During the a.m. feeding activity period, time spent feeding (~ = 32%, SO = 9.1) at the Hudson site was less than time spent feeding (~ (E 0.01). 74.6%, SO = 9.5) in the SLY = For the same activity period, time spent in alert behavior (~ = 47.6%, SO = 7.3) at Hudson differed (E = 0.01) from the time spent in alert behavior (~ = 17.0%, SO = 2.5) at the SLY site. Locomotor activity at the Hudson site (~ = 18.7%, SO = 5.3) was more frequent (E = 0.03, Wilcoxon test) than at the SLY (~ = 9.9%, SO = 1.6). Compafisons made among the 3 primary behaviors (feeding, alert, and locomotion) during the p.m. feeding period yielded no significant differences. than (E = Feeding time at Hudson (~ = 33.2%, SO = 21.8) was less 0.03) time spent feeding in the SLY (~ = 78.7%, SO = 1.0). At Hudson, time spent in alert behavior (~ = 39.9%, SO = 2.1) was greater than (E = 0.03) time spent alert in the SLY (~ 1.4). Locomotion activity averaged 20.0% (SO and 10.0~~ (SO significant = = 11.1%, SO 9.5) at the Hudson site 2.4) at the SLY site, however the difference was not (E = 0.06). DISCUSSION Communal avian behavior has most frequently been explained by 4 hypotheses: (1) the predation avoidance hypothesis, which proposes that the risk of predation for an individual is reduced by increased vigilance and dilution of prey (Lack 1968), (2) the information center �525 Table 2.5. Comparisons of 3 primary behaviors during the a.m. feeding and p.m. feeding activity periods at the traditional and non-traditional stopover sites. Activity Period Activity Non-Traditional X (%) SO Traditional X (%) SO A.M. Feeding Alert 47.6 7.3 17.0 2.5 0.0069 Feeding 32.0 9.1 74.6 9.5 0.0069 Locomotion 18.7 5.3 9.9 1.6 0.0253 Alert 39.9 2.1 11.1 1.4 0.0304 Feeding 33.2 21.8 78.7 . 1.0 0.0304 Locomotion 20.0 9.5 10.0 2.4 0.0606 P.M. Feeding pl denotes ~robability level for Wilcoxon test of no difference in percent of time spent in each behavior between stopover sites. �526 hypothesis, in which individuals find out about the location of good feeding sites by following others (Ward and Zahavi 1973), (3) the patch-sitting hypothesis, super-abundant which suggests that roosts form near locally food patches (Caccamise and Morrison 1986), and (4) the two-principal-strategies hypothesis (Weatherhead 1983), in which superior foragers roost communally because their status allows them access to central roosting positions that are buffered from predation by the surrounding subordinate individuals. Subordinate individuals pay the price of higher predation risk because of the foraging advantage they realize by following dominant individuals feeding locations (Weatherhead to superior 1983). Considering the "abundant forage available to sandhill and whooping cranes in the SLY, it seems unlikely that the information hypothesis or the patch-sitting communal behavior exhibited hypothesis would be the basis for in this location. Rather, time budget data on whooping crane #8422 support the predation avoidance principal strategies hypotheses. bird spent significantly center and two- During the period at the NTSS, the more time in alert behavior then when foraging at the TSS while surrounded by the sandhill flock. As a result of decreased alert behavior at the TSS the percent time spent in foraging significantly increased, increased vigilance as predicted by Krebs and Davies (1987). in the absence of a flock indicates the bird compensated for the loss of the flock vigilance by increasing alert behavior. Conversely, its own the decrease in alert behavior when it returned to the SLY indicates a recognition of decreased behavior. This need for alert A number of species allocate time to these behaviors in a manner dependent on flock size, as predicted by the hypothesis (Lazarus �527 1979, Caraco 1979, Barnard 1980, Bertram 1980). assumed that the percent time spent in alert behavior at the Hudson site was due to the absence of a surrounding flock and not influenced by unfamiliarity the area. of felt this assumption was justified because although it was a non-traditional site it was the third migration stopover period that #8422 had used the area. Decreased alert behavior in foster-reared whooping cranes compared to sandhill cranes of the same flock (R. C. Drewien, pers. commun.) may be the result of social status within the flock rather than a learnir.g deficiency. If whooping cranes were truly expressing chick-like behavior, assuming the necessity of alert behavior had not been learned, the percent time spent in vigilance would not have significantly increased when feeding alone. Thus, time budget data collected on #8422 as a solitary bird supports the concept of dominance position as a more probable explanation of decreased alert behavior by whooping cranes when foraging with a sandhill crane flock. Social dominance within a flock is known to influence the amount of alert behavior exhibited by individual birds within a flock. Waite (1987) found that subordinate social foragers exhibit increased vigilance when compared to dominant foragers within the same flock. He suggested that this increased vigilance is a result of subordinates keeping higherranking flock mates under surveillance. Caraco (1979) found subordinate yellow-eyed juncos (Junco phaeonotus) spent an increased amount of time watching over other flock members after being displaced by dominants. Incidents of dominance of whooping cranes over greater sandhill cranes has been observed within the Grays Lake flock (R. C. Drewien, pers. commun.). �528 Social interactions other than dominance vigilance also influence the unequal observed in individuals within a flock. Higher levels of alert behavior have been reported in males compared with females of several bird species. (Anas penelope) are more alert than females. found in ostriches guarding, Mayhew (1987) found that male European wigeons A similar result was (Struthis camelus) by Bertram (1980). Mate- territorial defense, increased predator risk for conspicuous males, and potential mate searching are hypotheses that have been tested to explain different vigilance patterns between sexes. All whooping cranes in the Grays Lake flock are currently non-breeders and could thus be classified as subadults, eliminating the need for increased vigilance by any individuals Bishop and Blankenship based on these social dynamics. (1982) investigated the dynamics of subadult flocks of whooping cranes at Aransas NWR, Texas. Subadults are the only age class that exhibit gregarious Chicks remain with behavior. their parents throughout their first winter and breeding pairs establish territories. and aggression Food abundance at Aransas NWR was not limiting among the subadults was minimal, thereby decreaSing need for conspecific surveillance. the Thus decreased alert behavior of the Grays Lake whooping cranes compared to sandhill cranes of the same flock may be an artifact of their non-breeding sandhill cranes in a breeding population as a result of conspecific surveillance avoidance exhibiting behavior. The foster-reared status. In contrast, may exhibit greater vigilance and not increased predator whooping cranes may be sufficient predator surveillance but not increased alert behavior associated with the social dynamics of a breeding population. �529 It is likely that the whooping vigilance and early warning situation was described (Vanellus vanellus), headed gulls Barnard vigilance and golden warning. Whooping feeding higher interactions apricaria), in mixed rate of responsiveness. plovers flocks and black- (Thompson and the greatest Gulls provided the benefit of added vigilance the and early cranes of the Grays Lake flock may also be in which of this study can only sugg~st which could begin to address Further investigation among sandhill better understand one species possible the social of individual cranes and whooping the possible avenues of dynamics behavior cranes of this and social is needed to effects of this cross-fostering exoeriment. Comparisons associations and interactions between and within the information needed to ascertain could provide A parallel rates of responsiveness. The results unique flock. flock. to alarm of lapwings (Pluvialis from a mixed species association investigation from the added Of the 3 species, gulls exhibited lapwings exhibits for the responsiveness golden plovers and highest benefiting benefit in the heterospecific (Larus ridibundus) 1983). cranes of time budget data and analysis of the 2 crane species the social structure of this flock. LITERATURE CITED Abramson, M. 1979. Vigilance as a factor influencing among curlews Numenius arquata. Ibis 121:213-216. flock formation Allen, R. P. 1952. 3. 246pp. Soc., Res. Rep. The whooping Altmann, J. 1974. Observational Behavior 49:227-267. crane. Natl. Audubon study of behavior: Sampling methods. Barnard, C. J. 1980. Flock feeding and time budgets in the house sparrow (Passer domesticus L.). Behaviour 74:113-127. �530 Bertram, B. C. R. 1980. Behav. 28:278-286. Vigilance and group size in ostriches. Anim. Bishoo, M. A. and D. R. Blankenship. 1982. Dynamics of subadult flocks of whooping cranes on the Aransas National Wildlife Refuge, Texas.. Pages 180-189 in J. C. Lewis, ed. Proc. 1981 Crane Workshop. Natl. Audubon Soc., Tavernier, Fl. Caccamise, D. F. and D. W. Morrison. 1986. Avian communal roosting: implications of diurnal activity centers. Am. Nat. 128:191-198. Caraco, T. 1979. Time budget ing and group size: Ecology 60:618-627. a test of theory. Cowardin, L. M., V. Carter, F. C. Golet, and E. T. LaRoe. 1979. Classification of wetlands and deepwater habitats of the United States. U. S. Dep. Inter., Fish and Wildl. Serv., Biol. Servo Prog., nJSjOBS-79j31. 103pp. Currier, P. J. and J. W. Ziewitz. crane model to the management Pages 315-325 in J. C. Lewis, Natl. Audubon Soc., Tavernier, 1987. Application of a sandhill of habitat along the Platte River. ed., Proc. 1985 Crane Workshop. Fl. Drewien, R. C. 1982. Whooping crane transplant experiment. Rep., Idaho Coop. Wi 1dl. Research Uni t. Job Prog. , and W. M. Brown. 1983. Whooping crane transplant experiment. -----Job Prog. Rep., Idaho Coop. Wildl. Research Unit. , . 1984. Whooping crane transplant experiment. ------JobProg. Rep., Idaho Coop. Wildl. Research Unit. Erickson, R. C. and S. R. Derrickson. 1981. The whooping crane. Pages 104-118 in J. C. Lewis. ed., Crane research around the world, Tntl. Counc. for bird preservation. Intl. Crane Foundation. Baraboo, \H. Howe, M. 1987. Habitat use by migrating whooping cranes in the Aransas-Wood Buffalo corridor. Pages 303-311 in J. C. Lewis, ed. Proc. 1985 Crane Workshop. Natl. Audubon Soc., Tavernier, Fl. Johnson, K. A. and S. A. Temple. 1980. The migratory ecology of the whooping crane. Unpublished report, contract 14-16-0009-78-034, U. S. Fish and Wildl. Serv., Washington, D. C. 120pp. Knight, S. K. and R. L. Knight. 1986. Vigilance patterns of bald eagles feeding in groups. Auk 103:263-272. Krapu, G. L. 1979. Sandhill crane use of staging areas in Nebraska. Pages 1-5 in J. C. Lewis, ed., Proc. 1978 Crane Workshop. Natl. Audubon Soc., Fort Collins, CO. �531 Krapu, G. L., D. E. Facey, E. K. Fritzell, and D. H. Johnson. 1984. Habitat use by migrant sandhill cranes in Nebraska. J. Wildl. Manage. 48:407-417. Krebs, J. R. and N. B. Davies. 1987. An introduction to behavioral ecology. Blackwell Scientific Publ., Oxford, England. 291pp. Lack, D. 1968. Ecological adaptations for breeding in birds. Methuen, London. Lazarus, J. 1979. The early warning function of flocking in birds: an experimental study with captive Ouelea. Anim. Behav. 17:855~ 865. Lingle, G. R., G. A. Wingfield, and J. W. Ziewitz. 1988. The migration ecology of whooping cranes in Nebraska, U. S. A .. Proc. Int. Crane Workshop (in press) Mayhew, P. W. 1987. Vigilance levels in European wigeon - sexual differences. Wildfowl 38:77-81. Melvin S. M. and S. A. Temple. 1982. Migration ecology of sandhill cranes: a review. Pages 73-87 in J. C. Lewis, ed. Proc. 1981" Crane Workshop. Natl. Audubon Soc., New York, N. Y. Powell, G. V. N. 1974. Experimental analysis of the social value of flocking by starlings (Sturnus vuloaris) in relation to predation and foraging. Anim. Behav. 22:501-505. Tacha, T. C. 1981. Behavior and taxonomy of sandhill cranes from midcontinental North America. Ph.D. Thesis, Oklahoma State Un;v., Stillwater. 112pp. Thompson, D. B. A. and C. J. Barnard. 1983. Antipredator responses in mixed -species associations of lapwings, golden plovers, and blackheaded gulls. Anim. Behav. 31:585-593. U.S. Fish and Wildlife Service. 1981. The Platte River ecology study. Spec. Res. Rep., Northern Prairie Wildl. Res. Ctr. Jamestown, N.D. 187pp. Waite, T. A. 1987. Vigilance in the white-breasted nuthatch: of dominance and sociality. Auk 104:429-434. effects Ward, P. and A. Zahavi. 1973. The importance of certain assemblages of birds as "information centers" for food finding. Ibis 115:517534. Weatherhead, P. J. 1983. Two principal strategies in avian communal roosts. Am. Nat. 121:237-243. ��Table Bl. Time spent in diurnal activities by whooping crane #8422 on 18 October 1986 near Hudson, Colorado. Activities were recorded at 15-second intervals. Act iv i ty it J:L__[g~Ji!)g 8..._l!:._ UQ!!~l n % n - - 42 26.6 II a 0.0 87 55. I 0 - 0 - Feeding Orinking Alert - LQafing P. M. reedj!.!~ P. ~1. Roo s t l_Qta 1 % n % 11. 1 304 50.0 3 2.9 360 37.2 0 0.0 0 0.0 2 2.0 2 0.2 54 54.5 223 36.7 45 44. I 409 42.3 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0.0 28 28.3 7 1.1 30 29.4 65 6.7 29 18.3 6 6.1 68 11.2 22 21.6 125 12.9 a 0.0 0 0.0 0 0.0 0 0.0 a 0.0 a 0.0 0 0.0 0 0.0 0 0.0 0 0.0 a 0.0 a 0.0 6 1.0 a 0.0 6 0.6 99 100.0 608 100.0 102 100.0 967 100.0 n % n % n % ):::0 "U \J Hesting rn Z 0 I-< Cotuf ur l Locomotion Agonistic Vocal izat ion - Gut of Sight - - . - - - - Total data __ "_ 158 >< CP .. 100.0 points Minutes of 39.516.3 24.8 10.2 212.0 62.9 25.5 10.6 241.8 100.0 observat ion (%) _.----- . __ __ ._ .. .. -._ -- --- ----- --_ ...... _._---_.- .- t/l w w �VI LV .&:- Table B2. Time spent in diurnal activities by whooping crane #8422 on 19 October 1986 near Hudson, Colorado. Activities were recorded at 15-second intervals. Activity 8.:.-.l:L_nQQ~! lL_M. Feedjng IQ1~1 43.9 0 0.0 397 30.2 ·0 0.0 0 0.0 1 O. 1 51.0 188 4 1.0 60 100.0 600 45.7 2 0.7 0 0.0 0 0.0 2 0.2 0.4 92 31.3 3 0.7 0 0.0 97 7.4 104 20.8 39 13.3 65 14.2 0 0.0 208 15.8 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 n Feeding - - 192 Drinking - Alert - Resting - Comfort - locomotion - Agonistic n Ll'L_Boo ~ t % % - f..:_l!Jgg!J in9 n n - loafing n % 38.3 4 1.4 201 0 0.0 1 0.3 202 40.3 150 0 0.0 2 % % n % Vocalization - 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 Ollt of Sight - I 0.2 6 2.0 1 0.2 0 0.0 8 0.6 294 100.0 458 100.0 60 100.0 1313 100.0 .--- .. ~~.--- Total data - SOl - 125.3 38.2 100.0 point.s Minlltes of observation -_._----_. (%) 73.5 22.4 114.5 3·1.9 15.0 4.6 328.3100.0 �Table 83. Time spent in diurnal activities by whooping crane #8422 on 20 October 1986 near Hudson, Colorado. Activities were recorded at I5-second intervals. - -- - .._--_--- -_-_ - -- --_ .. -- -_- _- .__---_ _--- -----_._- ------_- .. Activity .... 1l.:_lL_fl!2 0 s t L!:L_f£~gin9 n % % n _._--------------- loaiil}9 n .. IQL!l L11,_£f~ging r.!._lL_noo~l % n % n % n % - 370 28.4 - 0 0.0 544 41.8 0 0.0 59 4.5 ------ - feeding I 0.9 218 44.7 151 21.4 - Drinking 0 0.0 0 0.0 0 0.0 - 62 57.4 174 35.7 308 43.6 - - - Resting 0 0.0 0 0.0 0 0.0 - - - Comfort 6 5.6 1 0.2 52 7.4 - 37 34.3 92 194 27.4 323 24.8 A~Joll i s L ie 0 0.0 0 0.0 0 0.0 0 0.0 Vocal i za t ion 0 0.0 0 0.0 0 0.0 0 0.0 Gilt of Sight 2 1.8 3 0.6 1 0.3 6 0.5 488 ]00.0 706 ]00.0 ]302 100.0 Alert I ucomo t ion Total data ]08 ]00 10.0 - - - points Minlltes of 27.0 8.3 122.0 37.4 176.8 325.8 100.0 54.3 observa lion (%) ._. o__ _"_ _______ _ _ VI W VI �Table B4. Time spent in diurnal activities by whooping crane #8422 on 21 October 1986 near Hudson, Colorado. Activities were recorded at 15-second intervals. A. ,.1. Roost Activity n % A. M. Feeding % n Loafing n % P. M. Feeding % n -- P. ,.1. Roost II % Total n % - feeding 69 46.0 69 46.0 Orinking o 0.0 o 0.0 69 4G.0 9 46.0 o 0.0 o 0.0 J\lel'l Resting Comfort 0.7 0.7 Locomotion 9 6.0 9 6.0 Agonistic o 0.0 o 0.0 Vocal izalion o 0.0 o 0.0 2 1.3 2 1.3 Ollt of Sight ---- Tolal dala ---------- 150 100.0 150 100.0 points Minutes of 37.5 100.0 observation ------_ .. (%) _-- -----_. 37.5 100.0 Vl W o- �Table 8S. Time spent in diurnal activities by whooping crane #8422 on 22 October 1986 near Hudson, Colorado. Activities were recorded at IS-second intervals. Ac t i v ity tL_f:L_H(H1H 8.!_!L_[~Quing n L!~i![iOg n f_,__!:1!_£~~Ui!lg E,-_ !:L_nQQ~t n % n - - 389 19.3 - 0 0.0 - 1152 57.3 0 0.0 55 2.7 - 408 20.3 - - 0 0.0 0.0 - - 0 0.0 0 0.0 - - 7 0.4 295 100.0 2011 ]00.0 n n % Feeding 15 15.0 197 29.1 67 7.1 110 37.3 Drinking 0 0.0 0 0.0 0 0.0 0 0.0 43 43.0 299 44. 1 690 73.6 120 40.7 - Resting 0 0.0 0 0.0 0 0.0 0 0.0 - COlilfort 4 4.0 4 0.6 47 5.0 0 0.0 37 37.0 173 25.5 133 14.2 65 22.0 - Agonistic 0 0.0 0 0.0 0 0.0 0 0.0 Vocalization 0 0.0 0 0.0 0 0.0 0 Out of Sight ] 1.0 5 0.7 ] O. ] 100 100.0 678 100.0 938 100.0 Alert locomotion Total data % % I111i!1 % % points Minutes of observation 25.0 5.0 169.5 33.7 234.5 46.6 73.8 14.7 502.8 100.0 (%) VI VJ --.J �\Jl VJ Table 86. Time spent in diurnal activities by whooping crane #8422 on 23 October Hudson, Colorado. Activities were recorded at IS-second intervals. 1986 near ----- Activity A. M~Qll A. ~1. n % Feeding 0 0.0 449 Drinking 0 0.0 16 Resting LtL BQQ~t n % n % n 26.4 - - - - 0 0.0 - - - 80.0 812 47.8 - - - 0 0.0 0 0.0 - - - Comfort 2 10.0 64 3.8 - - - locolllotion 2 10.0 ·361 21.2 AC]onistic 0 0.0 0 0.0 - - - - Vocal ization 0 0.0 0 0.0 - - - - Out of Sight 0 0.0 14 0.8 - - - Alert. Total data 20 n feeding Loafing ~_lL_feeding % 100.0 1700 100.0 IQtd mb~r n % - 2 1.4 451 24.2 - - 1 0.7 1 0.1 - - 59 40.4 887 47.5 - 0 0.0 0 0.0 17 11.6 83 4.5 • 67 45.9 430 23.0 - 0 0.0 0 0.0 - 0 0.0 0 0.0 0 0.0 14 0.7 146 100.0 1866 100.0 - - % n % points Millllles of observation 5.0 (%) 1.1 425.0 91.1 36.5 7.8. 466.5 100.0 co �Table B7. Time spent in diurnal activities by whooping crane #8422 on 24 October 1986 near Hudson, Colorado. Activities were recorded at 15-second intervals: --- I\ct iv i ty LtL B!'!QH LtL_£~~~jj!!g Loafing n % n feeding - - 173 Orinking - - Alert - Resting __ --'---------- - L!L_£f_l1~U !EJ --- - - - e e.; - - -------------------- IQi!!l tL__BQQH n % n % n % n 30.6 I 0.4 - - 25 3.3 199 12.7 0 0.0 0 0.0 - - 0 0.0 0 0.0 - 269 47.6 217 87.5 - - 444 59.1 930 59.5 - - 0 0.0 0 0.0 - - II 1.5 II 0.7 Comfort - - 2 0.4 21 8.5 - - 144 19.2 167 10.7 Locomotion - - 115 20.3 8 3.2 - 11.8 212 13.5 I\gonistic - 0 0.0 0 0.0 - 0 0.0 0 0.0 Vocal izat ion - 0 0.0 0 0.0 - 0 0.0 0 0.0 Out of Sight - 6 1.1 I 0.4 - 38 5. I 45 2.9 Total data - 565 100.0 248 100.0 - 751 100.0 1564 100.0 15.9 - - - % 89 - - % . points Minutes of observation - 141. 3 36.1 62.0 107.8 48.0 391.0 100.0 (%) V1 w \0 �VI Table B8. Time spent in diurnal activities by whooping crane #8422 on 25 October 1986 near Hudson, Colorado. Activities were recorded at I5-second intervals. -------------------------------------- Activity A. 11. Roost n % A.I·1. Feeding n Loafing n % % P. t·1. Feeding n --------- P. H. Roost n % --------- -- --- -- % Iotal n % ._--- Feeding 0 0.0 182 26.6 2 1. 4 2 0.6 186 14.2 Drinking 0 0_0 a 0.0 o 0.0 0 0.0 o 0.0 52 30.0 365 53.3 61 41.2 177 52. I 655 50.0 Resting 0 0.0 o 0.0 o 0.0 12 3.5 12 0.9 Comfort 46 33.6 8 1.2 28 18.9 )27 37.3 209 16.0 Locomotion 35 25.5 117 17 . I 48 32.4 20 5.9 220 16.8 Agonistic 0 0.0 o 0.0 o 0.0 0 0.0 o 0.0 Vocal i za l i on a 0.0 o 0.0 o 0.0 0 0.0 a 0.0 Out of Sight 4 2.9 13 1.9 9 6. I 2 0.6 28 2. 1 100.0 1310 100.0 Alert --_---------_. ------- Total data ]37 100.0 685 100.0 )48 100.0 340 points Minutes of observation 34.3 ]0.5 171.3 52.3 37.0 11.3 (%) ------------ __ .. -- -- --_._. -_ .. ------------------------- ..--_ .. 85.0 25.9 327.5 ]00.0 ~ o �Table 89. Time spent in diurnal activities by whooping crane #8422 on 26 October Hudson,Colorado. Activities were recorded at 15-second intervals. Activity 8J:L_ BQ~!~i n Feeding % - Drinking A.M. feeding ---------.~ !.Q2f in9 £_,!:L__£QgJ in<J % n % n 98 19.4 - - - 0 0.0 n % 1986 near £ JL_BQQ~ t n % n - 98 19.4 0 0.0 - 297 58.7 - 0 0.0 9 1.8 - 102 20.2 - 0 0.0 - 0 0.0 - 0 0.0 - - JQL.!!l % Alerl - 297 Restillg - 0 0.0 Comfort - 9 1.8 102 20.2 - 0 0.0 - - 0 0.0 - - 0 0.0 - 506 100.0 150 100.0 126.5 100.0 126.5 100.0 I.ocolllotion Agonistic - Vocalization - Out of Sight - Tota 1 - 5£3.7 . - - - data points ~1inlltes of observation (%) VI .j::-- •..... �V1 po. N Time spent in diurnal activities by whooping crane N8422 from 18-26 October 1986 near Table BID. Hudson,Colorado. Activities were recorded at IS-second intervals. --------" -_._- ----- .. -.--.---.-~----_ Activity BJL_E!'!Q~! BJ:L_Fegg ina n n % % --_ LQa finn n % ~_,_lleding n % ~-~ r.J:L_.BQQ~l n IQli!l Q!J!~[ % n % n % 2.9 ---------- Feeding 16 4.4 J620 29.8 234 Drinking 0 0.0 0 0.0 I 173 47.4 2574 47.4 Alert 617 40.9 30 2.4 2 1.4 519 O. I 0 0.0 1 O. I 1 0.7 4 1419 62. I 592 39.2 726 57.9 59 40.4 5543 50.4 10.2 o. I Resting 0 0.0 0 0.0 2 0.1 0 0.0 23 1.8 0 0.0 25 0.2 Comfort 58 15.9 91 1.7 240 10.5 38 2.5 301 24.0 17 11.6 745 6.8 III 30.4 1102 20.3 380 16.6 246 16.3 131 10.6 67 45.9 2037 18.5 Agonistic 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 Vocalization 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 Out of Sight 7 1.9 44 0.8 9 0.4 16 1.1 40 3.2 0 0.0 116 1.1 365 100.0 5431 100.0 2285 100.0 1509 100.0 1253 100.0 146 100.0 10989 100.0 locomotion Total data points MillllLes of observation 90.3 3.3 (%) 1356.8 49.4 570.3 20.8 376.3 13.7 312.3 11.4 36.5 7.8 2746.3 100.0 �543 APPENDIX C Table CI. Time spent in diurnal activities by whooping crane #8422 on 3 November 1986 in the San Luis Valley, Colorado. Activities were recorded at IS-second intervals. Activity A. M. Feeding n Feeding % P. M. Feeding n % n % 718 67.0 87 79.1 805 68.2 0 0.0 0 0.0 0 0.0 218 20.4 14 12.7 232 19.6 Resting 0 0.0 0 0.0 0 0.0 Comfort 8 0.7 1 0.9 9 0.8 126 11.8 8 7.3 134 11.3 Agonistic 0 0.0 0 0.0 0 0.0 Vocalization 0 0.0 0 0.0 0 0.0 Out of Sight 1 0.1 0 0.0 1 0.1 1071 100.0 110 100.0 1181 100.0 Drinking Alert Locomotion Total data points Minutes of observation 317.8 (%) 90.7 27.5 9.3 355.3 100.0 �544 Table C2. Time spent in diurnal activities by whooping crane #8422 on 4 November 1986 in the San Luis Valley, Colorado. Activities were recorded at IS-second intervals. Activity A. M. Feeding n Feeding % P. M. Feeding n % n % 553 67.2 431 79.7 984 72.2 a 0.0 0 0.0 a 0.0 132 16.1 55 10.2 187 13.7 Resting a 0.0 0 0.0 a 0.0 Comfort 53 6.4 0 0.0 53 3.9 Locomotion 80 9.7 55 10.1 135 9.9 Agonistic a 0.0 0 0.0 a 0.0 Vocalization a 0.0 0 0.0 a 0.0 Out of Sight 4 0.5 0 0.0 4 0.3 822 100.0 541 100.0 1363 100.0 Drinking Alert Total data points Minutes of observation 205.5 (%) 60.3 135.3 39.7 340.8 100.0 �545 Table C3. Time spent in diurnal activities by whooping crane #8422 on 5 November 1986 in the San Luis Valley, Colorado. Activities were recorded at IS-second intervals. Activity A. t~. Feeding n Feeding % Total P. M. Feeding n % n % 353 77 .2 282 77 .3 635 77 .3 0 0.0 0 0.0 0 0.0 66 14.4 35 9.6 101 12.3 Resting 0 0.0 0 0.0 0 0.0 Comfort 1 0.2 0 0.0 1 0.1 36 7.9 48 13.1 84 10.2 Agonistic 0 0.0 0 0.0 0 0.0 Vocalization 0 0.0 0 0.0 0 0.0 Out of Sight 1 0.2 0 0.0 1 0.1 457 100.0 365 100.0 Drinking Alert Locomotion Total data 822 100.0 points Minutes of observation 114.3 (%) 55.6 91.3 114.4 205.5 100.0 �546 Table C4. Time spent in diurnal activities by whooping crane #8422 on 6 November 1986 in the San Luis Valley, Colorado. Activities were recorded at IS-second intervals. A. r~. Feed i ng Activity n Feeding % P. M. Feeding n % n % 134 87.0 400 78.0 534 80.1 0 0.0 0 0.0 0 0.0 12 7.8 76 14.8 88 13.2 Resting 0 0.0 0 0.0 0 0.0 Comfort 0 0.0 1 0.2 1 0.1 Locomotion 8 5.2 36 7.0 44 6.6 Agonistic 0 0.0 0 0.0 0 0.0 Vocalization 0 0.0 0 0.0 0 0.0 Out of Sight 0 0.0 0 0.0 0 0.0 154 100.0 513 100.0 667 100.0 Drinking Alert Total data points t~inutes of observation 38.5 (%) 23.1 188.3 76.9 226.8 100.0 �547 Table C5. Time spent in diurnal activities by whooping crane #8422 from 3-6 November 1986 in the San Luis Valley, Colorado. Activities were recorded at IS-second intervals. Activity A. M. Feedina n Feeding % P. M. Feedina % n n % 1758 70.2 1200 78.5 2958 73.3 0 0.0 0 0.0 0 0.0 428 17.1 180 11.8 608 15.1 Resting 0 0.0 0 0.0 0 0.0 Comfort 62 2.5 2 0.1 64 1.6 250 10.0 147 9.6 397 9.8 Agonistic 0 0.0 0 0.0 a 0.0 Vocalization 0 0.0 a 0.0 a 0.0 Out of Sight 6 0.2 0 0.0 6 0.2 2504 100.0 1529 100.0 4033 100.0 Drinking Alert Locomotion Total data points Minutes of observation 626.0 (%) 62.1 382.3 37.9 1008.3 100.0 ��549 CHAPTER 3 ROOST SITE SELECTION OF WHOOPING CP~ES AT NON-TRADITIONAL FALL MIGRATION STOPOVER SITES IN EASTERN COLORADO SUMMARY Roost site selection investigated by whooping at 2 non-traditional in eastern Colorado. cranes (Grus americana) fall migration stopover NTSS were used by 2 whooping fostered flock during fall 1985. One whooping cranes was sites (NTSS) of the cross- crane returned" to the same NTSS it used in fall 1985 during spring and fall migration stopovers of 1986. Two roosting near Hudson, Colorado Severence NTSS. wetlands were used at the NTSS located and 1 wetland was used for roosting Characteristics common among roosting included areas of water depth < 30 cm, isolation close proximity wetlands. conductivity « and distances There was no consistency horizontal Whooping from disturbance, Both Hudson roost sites were similar in size, However, these characteristics site. wetlands 2 km) to feeding sites, loafing areas, of water, visibility at the and similar specific to power lines and fences. were not shared by the Severence among the 3 wetlands or vegetation and composition migration greater sandhill crane (Grus canadensis of and density. cranes of the Grays Lake experimental exhibit the gregarious for percent roost flock usually behavior common to their tabida) parents. foster These cross- �550 fostered whooping cranes migrate as individuals, or occasionally in groups of 2 or 3, within the sandhill crane flock (R. C. Drewien, Prog. Rep. Whooping Crane Egg Transplant winters near Bosque-del-Apache Experiment 1-20). This crane flock National Wildlife Refuge (NWR), New Mexico and summers at Grays Lake NWR, Idaho (Stahlecker 1986). Normally they concentrate in the traditional spring and fall stopover sites in the San Luis Valley of southcentral Colorado. fall migration During the 1985 however, 2 subadult whooping cranes from the Grays Lake flock (Pat 4 and #8422) used 2 separate non-traditional (NTSS) in eastern Colorado (Dennis 1985). stopover sites Whooping crane #8422 returned to its previously used eastern Colorado NTSS during the 1986 spring and fall migration. Evaluating information cranes. habitat on these NTSS will add to the limited available on 'habitat requirements of migrating whooping Comparing roost site selection at NTSS with roost sites used at TSS could provide insights into habitat use changes associated with the presence or absence of a surrounding the use of non-traditional management flock. Information concerning stopover sites could also be applied to of whooping cranes during any occurrence outside of the normal range. The objectives biological and of this study were to: and physical characteristics (2) develop standardized methodology of non-traditional comprehensive sites. (1) measure selected of NTSS in eastern Colorado, for future habitat evaluation stopover sites to facilitate consistent, data collection for any future use of non-traditional �551 STUDY AREA The 2 NTSS were located in southern Weld County of eastern Colorado. The NTSS used by whooping crane Pat 4 during fall 1985 was located 1 km east of Severence, Colorado. was used at this site. One roosting wetland (S[l]) Two roosting wetlands (H[1], H[2]) were used at the NTSS used by #8422 during fall 1985 and spring and fall 1986. site was located 2 km south of Hudson, Colorado. This Topography is broadly rolling with an elevation of 1512 m at the Hudson site and 1477 m at the Severence site. Irrigated farmland in the area supports the main crops of corn, alfalfa, wheat, and sugar beets. vegetables are grown in lesser amounts. Malting barley and The 3 roosting wetlands were classified as (system) palustrine, (class) emergent wetland, and (modifier) saturated/semi-permanent/seasonal wetlands (PEMY; Cowardin et al. 1979). The Severence roosting wetland used by whooping crane Pat 4 was an irrigation reservoir surrounded by dense cattails (IYQh£ latifolia). The feeding site used at this NTSS was an open corn stubble field 0.1 km east of the roost site. Feeding sites used by whooping crane #8422 at the Hudson NTSS were fields of volunteer barley, corn, wheat, and hay, all located < 1.5 km from the roost sites. Both roost sites used at the Hudson NTSS were stock ponds located in grazed cattle pastures. Loafing areas were adjacent to the roosting wetlands at both NTSS. METHODS Habitat evaluations were conducted on the 3 NTSS roosting wetlands. Criteria for habitat evaluations were based on published literature concerning habitat requirements of migrating cranes (Allen 1952; Johnson and Temple 1980; Lingle et al. 1984, 1988; Howe 1987; �552 Ward and Anderson 1987}. Variables and techniques used for measurement were described in chapter 1. A standardized field form was developed by combining the U. S. Fish and Wildlife Service and Colorado Division of Wildlife whooping crane sighting report forms. Additional questions were prompted by current literature and field observations (Appendix D). RESULTS Whooping crane Pat 4 used the Severence NTSS from 23 September to 29 October 1985. S(I}, a 21.0-ha irrigation reservoir, was located only 6 m from a road and 75 m and 78 m from the nearest building and house respectively (Table 3.1). Visual isolation from these potential disturbances was proyide by dense cattails (Typha latifolia) surrounding the northern end of the wetland. These cattails were> 3 m high and resulted in only 10% horizontal visibility from the 20-cm water depth contour (Fig. 3.1). Pat 4 roosted in the shallow northern end of the wetland (Fig. 3.2), but the specific location of the roost was unknown. The greatest distance from shoreline to the 20-cm water depth contour was 84.0 m. Distance to feeding site was 0.1 km. Whooping crane #8422 used the Hudson NTSS from 11 September to 29 October 1985, 15-29 April 1986, and 17-26 October 1986. The same roosting wetland (H[l]) was used during all 3 stopover periods and an additional roosting wetland (H[2]) was used 2 nights during fall 1986. H(l), a l.l-ha stock pond, was characterized by extensive horizontal visibility (Fig. 3.1) and isolation from potential disturbance and hazards (Table 3.1). The wetland was surrounded by grazed pasture with sedges (Carex spp.) at waters edge. Horizontal visibility was extensive in all directions and visual obstruction by �Table 3.1. Habitat evaluations for the 3 roosting wetlands located at HISS in eastern Colorado. -- Roost Dis tance to 12Q1en tiAl__Qli!J!rbance Specific Conductivity location Size (Site) (ha) !IO!!5e Roag {luilging of IJater Oi~t~nce to potential Fence (nuuho sZcm) (Ill ) hazard Power line (m) --._._- S (1) 21.0 78 6 75 2600 0 45 II( 1) 1.1 660 630 600 4400 16 360 1I(2} 1.3 600 700 600 3700 0 700 VI VI W �554 Fig. 3.1. Mean (± SO) horizontal visibility wetlands in eastern Colorado. of 3 NTSS roosting �555 { .: ! .•. / " " " i ; water depth '\ , I I Wetland edge 10 cm contour 20 cm contour 30 cm contour 40 cm contour / (' j ,/" / / ./ I 20 m Fig. 3.2. Water depth profile of wetland S(l). �556 west end of the wetland. The roost location was in the area of most vegetation occurred only in the lower 0.2S-m section of the profile board. Other obstructions resulted from topography and a dike on the gradual slope and greatest distance (6 m) from shoreline to the 20-cm water depth contour (Fig. 3.3). The second roost site used at the Hudson NTSS was similar to H(l) in distance from potential disturbances and hazards, wetland size, and specific conductivity. Horizontal visibility was obstructed at the eastern end of H(2) by cattails and on the west end by a dike. The cattails had been beaten down by a hail storm and only obstructed view below 1.5 m (Fig 3.1). roosting. Whooping crane #8422 used 2 specific sites for Both roost sites occurred away from the cattails in are~s where sedges and spikerushes emergent vegetation. (Eleocharis spp.) were the dominant Water depth was < 40 cm throughout the wetland (Fig. 3.4). Four feeding sites were used by #8422 at the Hudson NTSS, all located within a 1.S-km radius of H(I). H(2) was 1.5 km. The distance between H(I) and When using roost H(2), ~8422 used the same feeding sites as when roosting at H(I). DISCUSSION Whooping cranes are evidently tolerant of a broad range of natural and human-modified habitats during migration (Johnson and Temple 1980, Erickson and Derrickson 1981, Lingle et al. 1984, Howe 1987, Ward and Anderson 1987). Despite evidence that migrating whooping cranes are habitat generalists certain patterns of habitat selection are apparent. Johnson and Temple (1980) summarized wetland characteristics for roost sites used by whooping cranes of the Aransas-Wood Buffalo flock. These �557 ... ,-.;- .................. ---------=----=-------:----::- I I \ ~.;.~7:_::..~:.:_:.:::::::-:.:-~:.:::-:.:-.--::-~:..~.~.~ _-=-_ -.~.~:.:::-;::::: . ::-::-:. _ . ~ - ... , . ,;; ':. " " /? . ;(- .' , '\ \, ". . . \ ' " " , .. ' , : : , , . , . : " ' \ 40 cm > ".. '-. , ':.:: \ . water depth . ,, ,:' /p ".' 7 \._, , " , " " '. " " " " " \. , ., ., '," " ""''''' " '. \. ," ,.". ,':, ' .' . \ \ \ /'/;/ I ~~.~:' f r ,,' ',,' " ./' : .' :.: . ...... - r , , r ', " .'/ , \ . ,, , ' ·· ., ·, , . ,' ,. ', . ' , ,, . . ' , , ,, '' , ' " " " " ' " ., " " ; j ,, , , , , : ,: ," , , , . Wetland edge 10 em contour 20 em contour 30 em contour 40 em contour " " ' ; ! " ., '' , .' , ' ,, ' ,, '. , , ,, , , ' , " ·· ,' : : I , , , . ~ , :: . ,,, , 5m , \ :~ \: \ I. ".: '. \ " \" , . ,: ....•• ' ••••--:-+-1 __ - Roost location •• Fig. 3.3. Water depth profile of wetland H(l). �558 ........................................... - ._- .... ---.--------. .................. ........................... -._------ ) .----------- ------------ ----------_------ ~ \ J '\::.',: '.\ .... . <.; ;~~.~ \ x.'. , ~ <, ~ ........ ••••.•••• Roost location , , , , '~': \ ' ~:, I ... : I ~: ; , '. " <, , : , , ; : ' .. : : , , < ' : ' : , : , : , : , .: ', : , : , \. 40 em water depth : \ \, [ 1 , .' / i :, I ' I' I: I: i\ \ I / '. , / / ' \ ',' i t / / Wetland edge 10 em contour 20 em contour 30 cm contour 40 em contour l- I 10 m Fig. 3.4. Water depth profile of wetland H(2). �559 included shallow water, extensive horizontal visibility, either sparse or short emergent vegetation, close proximity to feeding sites, and isolation from potential hazards and disturbance. characteristics The roost site of the 2 eastern Colorado NTSS used by foster-reared whooping cranes fit well within the parameters described by Johnson and Temple (1980). When compared with the TSS in the SLV used by cranes of the Grays Lake flock however, several characteristics inconsistent, particularly, were distances to potential disturbance and hazards. In the SLV, roost sites are frequently located near roads and power lines. The close pr~ximity of roost sites to power lines in this region is a result of extensive use of center pivot sprinklers for irrigation. Several possible explanations for the lack of isolation from disturbance in the SLV include: (1) the familiarity of the site as a result of traditional use, (2) the gregarious behavior of the Grays Lake whooping cranes provides additional flock vigilance, and (3) a habituation to human disturbance resulting from the greater accessability of breeding, stopover, and wintering grounds (see chapter 1). The roost sites used by Grays Lake whooping cranes at the NTSS were isolated from disturbance. Alert behavior of whooping crane #8422 increased at the NTSS when compared with behavior at the TSS due to the loss of a surrounding flock (see chapter 2). The greater isolation of the NTSS roosting wetlands might also be a response to loss of flock vigilance and unfamiliarity with the sight. Hudson NTSS were isolated by distance. The 2 roost sites at the The Severence NTSS roosting wetland was visually isolated from disturbances stand surrounding by a dense cattail the used portion of the wetland. Although whooping �560 cranes are thought to avoid areas of dense vegetation, emergent aquatic plants such as cattails and bulrush (Scirous spp.) might be an exception (W. M. Brown, pers. commun.). Suitable roosts usually consist of open water that enables whooping cranes to detect, either visually or audibly (splashing water), the approach of a predator (Ward and Anderson 1987). It would be difficult for a predator to approach a roosting crane through a stand of cattails or bulrush without detection because they are dense emergent aquatic plants. Whooping crane #8422 used a complex of 2 roost sites, 4 feeding sites, and 2 loafing areas at the Hudson NTSS. The bird also landed at 2 other wetlands for brief periods following hazing by dogs at a feeding site and a loafing area. Although Pat 4 used only 1 roost site and adjacent loafing area and 1 primary feeding site, it also infrequently used 2 surrounding pastures and 1 wetland while loafing and feeding. This pattern of using a complex of required activity sites (roost, feeding, and loafing areas) is similar to that observed in whooping cranes at the TSS in the SLY (see chapter 1). Use of such a complex provides cranes with sufficient habitat in the event disturbance occurs at anyone of the used sites. When flushed from an activity site or when humans were present at the site as cranes attempted to fly in, whooping cranes in the SLY flew to other nearby suitable activity sites (chapter 1). Whooping cfane #8422 flew to H(2) after being flushed from the loafing area adjacent to H(l). The bird remained to loaf at the new site and later returned there to roost after its evening feeding period. This use of complexes should be considered in management of future NTSS. Disturbance should be minimized at several suitable roosts, feeding sites, and loafing areas �561 to provide the whooping crane sufficient habitat in the event disturbance occurs on any of the used activity sites. Habitat use and behavior of whooping cranes at future NTSS in Colorado should be documented in a consistent manner. A standardized field form (Appendix 1) should be used for habitat evaluations to facilitate comparisons with other whooping crane stopover sites and to add to the limited information available on requirements of this species during migration. LITERATURE CITED Allen, R. P. 3.246pp. 1952. The whooping crane. Natl. Audubon Soc., Res. Rep. Cowardin, L. r1., V. Carter, F. C. Golet, and E. T.· LaRoe. 1979. Classification of wetlands and deepwater habitats of the United States. U. S. Dep. Inter., Fish and Wildl. S.erv., Biol. Servo Prog., FWS/OBS-79/31. 103pp. Dennis, J. A. 1985. Whooping cranes in eastern Colorado. Field Ornith. J. 19:77-78. Colorado Erickson, R. C. and S. R. Derrickson. 1981. The whooping crane. Pages 104-118 in J. C. Lewis, ed. Crane research around the world, Int. Counc. for bird preservation. Int. Crane Foundation. Baraboo, WI. Howe, M. 1987. Habitat use by migrating whooping cranes in the Aransas-Wood Buffalo corridor. Pages 303-311 in J. C. Lewis, ed. Proc. 1985 Crane Workshop. Natl. Audubon Soc., Tavernier, Fl. Johnson, K. A., and S. A. Temple. 1980. The migratory ecology of the whooping crane. Unpublished report, contract 14-16-0009-78-034, U. S. Fish and Wildl. Serv., Washington, D. C. 120pp. Lingel, G. R., P. J. Currier, and K. L. Lingle. 1984. Physical characteristics of a whooping crane roost site on the Platte River, Hall County, Nebraska. Prairie Nat. 16:39-44. Lingel, G. R., G. A. Wingfield, and J. W. Ziewitz. 1988. The migration ecology of whooping cranes in Nebraska, U. S. A .. Proc. Int. Crane Workshop (in press). Stahlecker, D. W. 1986. The 1985 fall crane migration in the Rio Grande Valley, New Mexico. Unpubl. Rep., New Mexico Audubon Soc., Albuquerque. 22pp. �562 Ward, J. P., and S. H. Anderson. 1987. Roost site use versus preference by two migrating whooping cranes. Pages 283-288 C. Lewis, ed. Proc. 1985 Crane Workshop in J. �563 APPENDIX D WHOOPING CRANE MIGRATION STOPOVER SITE FIELD FORM Date: Recorder: Name -------------------- Telephone Agency/Organization Number of birds at the site: _ Adul ts _ Young _ Accompanying sandhill cranes Color-markings observed (include order of colored bands and left/right 1eg) : Time and duration of sightings: Location (direction and distance from nearest town, and legal description of site; township, range, and section location) Roosting wetland: _ Feeding site: Loafing area: I. Roost Site Description 'n'etlandsize: Wetland classification (Cowardin et al. 1976): Distance to nearest: Potential disturbance: Potent ia1 hazard: 1 ) house 1 ) power 1ine road 2) fence 3) building 3) other 2) 4) other �564 Water depth profiles: Derive from transects established wetland. at 10-m intervals across the Measure water depth along each transect, then record perpendicular distance to shoreline for water depths of 10, 20, 30, and 40 cm. Distance from shore to water depth (m) Transect 10 cm 20 cm 30 cm 40 cm A B C etc. Horizontal visib,lity: Measured with a 3-m high vegetation profile board divided into 0.5- m sections, with the first 0.5 m section sub-divided into 0.25-m increments. Viewing points are set at 10-m intervals along the 20- cm water depth contour of the wetland. 90-m transect is established From the viewing point, a perpendicular to the shoreline and percent visibility is measured. Percent visibilitv Transect A B C etc. at profile board increments (m) 0-0.25 .25-.50 .50-1.0 1.0-1.5 1.5-2.0 2.0-2.5 2.5-3.0 �565 Describe surrounding upland habitat types, land use: II. Feeding Site Description land use (agricultural etc.): Available grain: Distance from roosting wetland: III. Loafing Area Descriotion Land use: Distance from rODsting wetland: Comments: ��567 CHAPTER 4 MANAGEMENT IMPLICATIONS The following management recommendations are based on data collected during fall 1986 and 1987 in the San Luis Valley and at 2 non-traditional stopover sites in eastern Colorado. Due to small sample sizes and local conditions, such as agricultural these recommendations geographic areas. practices, might require alteration to accommodate other Management of roost site habitat for migrating whooping cranes (Grus americana) in the San Luis Valley should include maintenance of a complex of suitable roost sites (> 2), feeding sites, and loafing areas located within an area of 5 km. characteristics The physical of the roosting wetlands should include: (1) sufficient area of shallow water « 30 cm) to allow cranes to roost away from the waters edge, and (2) extensive horizontal visibility within a 90-m radius of the roost site. Juxtaposition of required habitats (roost, feeding, and loafing areas) could be used to manipulate areas of use. Provision of loafing areas near distant feeding sites ( > 4 km from the roost complex) might improve use rates. to be considered If distant feeding sites are part of the complex, loafing areas should be located within 3 km of the feeding site. This strategy could be used to support a higher density of birds or to compensate feeding sites near the roost. for the loss of To prevent abandonment, hunting and �568 other potential disturbances minimized, especially should be prohibited or at least at the roost complex. Development migration stopover sites should incorporate the landscape of suitable approach of a complex of suitable roosting wetlands, feeding sites, and loafing areas. A complex should not be developed where power lines divide adjacent required habitats. Non-traditional stopover sites (NTSS) may require g~eater isolation to compensate for loss of familiarity and surrounding flock vigilance. Throughout the stopover duration, disturbance should be minimized at several suitable roosts, feeding sites, and loafing areas to provide the whooping crane alternate undisturbed sites. non-traditional Habitat evaluations stopover sites should· be standardized to ensure the compatibility of (see chapter 3) of information collected over years. Behavior and daily activity patterns of whooping cranes at NTSS should be documented for comparisqn naturally-reared with whooping cranes in the SLV as well as whooping cranes during migration. These data could provide information on the social status of the cross-fostered cranes within the Rocky Mountain greater sandhill crane (Grus canadensis tabida) flock. Approved by ~ X es K. Ringe Go~ a whooping � https://cpw.cvlcollections.org/files/original/3fdb05925ec8868447a51a6307e7fb68.pdf 886ac70fd31f450337144245c1d476c1 PDF Text Text ~U~ULciUU u~v~s~on or W1iQi1re Wildlife Research Report July 1988 1 JOB PROGRESS REPORT State of Colorado Project No. W-153-R-2 Mammals Research ------------------------ Work Plan No. 1 --~~---------------- Multispecies Investigations Job No. 7 Period Covered: July 1, 1987 - June 30, 1988 Authors: Personnel: Terrestrial Research Publication, Editing and Library Service M. W. Hershcopf, L. H. Carpenter R. B. Gill, N. McEwen, L. Lovett, K. Chociej, R. Harrison, and all Mammals Researchers ABSTRACT During the 1987-88 Segment, 11 books were purchased for permanent reference by DOW personnel. Sixty additional publications were located, ordered, and obtained free of charge for use. Twenty-five theses were purchased, obtained on Interlibrary Loan, or given to the library. An additional 890 individual references requested by Mammals Researchers were located by library staff and made available for use. About 25 of these requests were not available locally and were obtained through interlibrary loans. Seven manuscripts were published in various journals. ��3 MAMMALS PUBLICATION EDITING AND LIBRARY SERVICES Marian W. Hershcopf and Len H. Carpenter P. N. OBJECTIVE To provide a centralized support program for manuscript editing and library services to facilitate publishing results of research conducted in projects 01-03-047 - 11700 and 01-03-048 - 11700, 11400, 16700. SEGMENT OBJECTIVES 1. To provide coordinated and efficient editing and library services and publish findings for all Colorado Mammals Research programs. 2. To provide for the centralized support program for Mammals Research editing, library, and publishing services so that Mammals Research scientists can be most efficient in publishing results of their research. SUMMARY OF SERVICES Publications purchased with Mammals Research funds and placed in the Research Center Library Chicago manual of style. 13th ed., revised and expanded. Chicago Press. Chicago. 738pp. Endler, J. A. 1986. Natural selection in the wild. Press, Princeton, N.J. 336pp. University of Princeton University Inglis, J. M., B. A. Brown, C. A. McMahan, and R. E. Hood. 1986. Deer-brush relationships on the Rio Grande plain, Texas. Kleberg studies in Natural Resources. Texas A&M University, Texas Agricultural Experiment Station, College Station. 80pp. Hason, C. F., and S. M. MacDonald. 1986. Cambridge University P~ess, New York. Otters; ecology and conservation. 236pp. Metcalf, F. compo 1987. The Penguin dictionary of modern humorous quotations. Penguin Books, New York. 3l9pp. Miles, H. 1984. 160pp. The track of the wild otter. St. Martin's Press, New York. National Research Council, National Academy of Sciences. 1984. Developing strategies for rangeland management. Westview Press, Boulder, CO. 2022pp. Weber, W. A. 1987. Colorado flora: Western slope. University Press, Boulder, CO. 530pp. Colorado Associated �4 Wemmer, C. M., ed. 1987. Biology and management of the Cervidae (Research Symposia of the National Zoological Park, Front Royal, VA, 1982). Smithsonian Institution Press, Washington, DC. 577pp. Workman, G. W. 1985. Western elk management; a symposium. University, Logan. 213pp. Utah State Wrigley, R. E., and R. W. Nero. 1982. Manitoba's big cat: the story of the cougar in Manitoba. Manitoba Museum of Man and Nature, Winnipeg, Canada. 68pp. Publications obtained free or at low cost In addition to books purchased with Federal Aid Funds, about 60 free reports and short publications from state or federal agencies or from private sources were located, ordered, and obtained for use by Mammals Research personnel. Theses purchased, obtained on Interlibrary Loan or as gifts for use by Reserachers Banks, T. 1985. Nonconsumptive wildlife-associated recreation in Wyoming. M.S. Thesis, University of Wyoming, Laramie. 161pp. Bateman, M. C. 1972. Winter shelter: some effects on the behavior and physiology of penned white-tailed deer. M.S. Thesis, University of Maine, Orono. 108pp. Boyce, M. S. 1974. Beaver population ecology in interior Alaska. Thesis, University of Alaska, Fairbanks. 161pp. Bradley, P. V. 1986. Ecology of river otters in Nevada. University of Nevada, Reno. 112pp. M.S. M.S. Thesis, Busher, P. E. 1975. Movements and activities of beavers, Castor canadensis, on Sagehen Creek, California. M.A. Thesis, San Francisco State University, San Francisco. 86pp. 1980. The population dynamics and behavior of beavers in the Sierra Nevada. Ph.D. Thesis, University of Nevada, Reno. 147pp. Christensen, K. M. 1984. Habitat selection, food habits, movements, and activity patterns of reintroduced river otters in central Arizona. M.S. Thesis, Northern Arizona University. 72pp. Cooley, L. S. 1983. Winter food habits and factors influencing the winter diet of river otter in north Florida. M.S. Thesis, University of Florida, Gainesville. Davison, R. P. 1975. The efficiency of food utilization and energy requirements of captive female fishers. M.S. Thesis, University of New Hampshire, Durham. 1980. The effect of exploitation on some parameters of coyote population. Ph.D~ Thesis, Utah State University, Logan. 153pp. �5 Gerlach, T. P. 1987. Ecology of mule deer on the Pinon Canyon Maneuver Site, Colorado. M.S. Thesis, Virginia Polytechnic Institute and State University, Blacksburg. 6lpp. Graf, W. 1943. Natural history of the Roosevelt elk. State University, Corvallis. 222pp. Ph.D. Thesis, Oregon Horner, M. A. 1986. Internal structure of home ranges of black bears and analyses of home range overlap. M. S. Thesis, North Carolina State University, Raleigh. 54pp. Kopf, V. E. 1983. The relationship between food intake and thyroid hormone concentrations in white-tailed deer. Ph.D. Thesis, Virginia Polytechnic Institute and State University, Blacksburg. l44pp. Lauhachinda, V. 1978. Life history of the river otter in Alabama with emphasis on food habits. Thesis, Auburn University, Auburn, AL. l85pp. McAda, C. W. 1977. Aspects of the life history of three catostomids native to the upper Colorado River Basin. M.S. Thesis, Utah State University, Logan. l04pp. Marcum, C. L. 1975. Summer-fall habitat selection and use by a western Montana elk herd. Ph.D. Thesis, University of Montana, Missoula. l88pp. Pedevillano, C. 1986. Mountain goat behavior at the Walton Lick and Highway 2 underpasses in Glacier National Park. M.S. Thesis, University of Idaho, Moscow. 110pp. Reid, D. G. 1984. Ecological interactions of river otters and beavers in a boreal ecosystem. M.S. Thesis, University of Calgary, Alberta. 2l0pp. Renecker, L. A. 1987. Bioenergetics and behavior of moose (Alces alces) in the aspen-dominated boreal forest. Ph.D. Thesis, University of Alberta, Edmonton, Canada. 265pp. Sandell, M. 1985. Ecology and behaviour of the stoat Mustela erminea and a theory on delayed implantation. Ph.D. Thesis, University of Lund, Lund, Sweden. l15pp. Sayre, R. 1987. Effect of shrub stems on microhistological estimates of ruminant diets. M.S. Thesis, Colorado State University, Fort Collins. 52pp. Stenson, G. B. 1985. The reproductive cycle of the river otter, Lutra canadensis, in the marine environment of southwestern British Columbia. Ph.D. Thesis, University of British Columbia, Vancouver. Whitman, J. S. 1981. Ecology of the mink (Mustela vison) in west central Idaho. M.S. Thesis, University of Idaho, Moscow. lOlpp. Zackheim, H. S. 1982. Ecology and population status of the river otter in south-western Montana. M.S. Thesis, University of Montana, Missoula. l03pp. �6 Reference document location and delivery The Research Center Library staff also located and delivered about 890 individual articles on request for Mammals Researchers during this segment; about 25 were not available locally and were obtained through Interlibrary Loan procedures. Manuscripts published Job Progress Reports; Federal Aid. Carpenter, L. H. 5(3):25-28. 1988. All Studies. The big herds: Colorado's White River elk. Hobbs, N. T. 1987. Elk survival during winter: conservation. Bugle 5(1):60-64. 1988. Springtime in the Rockies: Bugle 5(2):25-26. Bugle a question of energy a critical period for elk. 1988. The legacy of the Elkhorn Ranch: country. Bugle 5(3);31-32, 34. research on elk in cattle ____ ~, and D. M. Swift. 1988. Grazing in herds: when are nutritional benefits realized? Amer. Nat. 131(5):760-764. Miller, H. W., and N. T. Uobbs. 1988. Ivermectin for treating lungworms in mountain sheep: an appropriate technology with a specific utility. Wildl. Soc. Bull. 16:236-238. Robbins, C. T., T. A. Hanley, A. E. Hagerman, O. Hjeljord, D. L. Baker, C. C. Schwartz, and W. W. Mautz. 1987. Role of tannins in defending plants against ruminants: reduction in protein availability. Ecology 68(1):98-107 • Prepared by .Mc-n'CJ\_ tJ . ~ ~,n;lco~~ Marian W. Hershcopf Librarian Len H. Carpenter Wildlife Research Leader �7 Wildlife Research Report July 1988 JOB PROGRESS REPORT State of Colorado Project No. W-153-R-2 -----------------------No. 1 --~------------------ Mammals Research Work Plan Multispecies Investigations Job No. 9 Period Covered: July 1, 1987 - June 30, 1988 Author: Mammals 1 Research Administration Len H. Carpenter ABSTRACT Research superv~s~on for 5, full-time employees involved in various aspects of deer and elk research was provided during the 1987-88 segment. Considerable effort was spent in an attempt to bring research planning, budgeting, documentation, and evaluation in line with proposed Division-wide planning systems. Assignment of planning and evaluation responsibilities for state-wide deer and elk programs significantly impacted time available for research administration. ��9 MAMMALS I RESEARCH ADMINISTRATION Len H. Carpenter P. N. OBJECTIVE To supervise and administer research on deer and elk in the Mammals Project. SEGNENT OBJECTIVE To supervise and administer research on deer and elk in the Mammals Project. METHODS The position of Research Leader is established to supervise and administer all research conducted for the wildlife species of concern. In January, 1988, this position was broadened to also include responsibilities of planning and evaluation for statewide species programs. RESULTS AND DISCUSSION Considerable time was spent during the latter part of the segment evaluating the last 2 big game seasons in preparation for recommendations to be made concerning a new 3-year season structure framework for 1989-91. Effort was expended throughout the segment working to bring research planning, budgeting, documenting, and evaluating into compatible formats with overall Division planning systems. By the end of the segment, all Mammals 1 research personnel except one were finally equipped with personal computers. Prepared by /1. (c../~~~ ~I 1! Len H. Carpen r Wildlife Research Leader ��Wildlife Research Report July 1988 11 JOB PROGRESS REPORT State of Colorado Project No. W-153-R-2 ------------------------No. 2 ----------------------- Mammals Research Work Plan Deer Investigations Job No. 7 Period Covered: July 1, 1987 - June 30, 1988 Author: Development of Census Methods for Deer in Plains Riverbottom Habitats R. C. Kufeld Personnel: D. Bowden, D. North. ABSTRACT Seventy-four mule and white-tailed deer were trapped in Clover traps and a drop net in the South Platte riverbottom between Gilcrest and Sedgwick during January 6-February 11, 1988. Twenty-four adults (11 mule deer and 13 whitetails) were radio-collared and eartagged. Remaining deer, mostly fawns, were eartagged. These instrumented deer plus 25 others, radio-collared in January and February, 1987, were located by aerial telemetry at 2-week intervals to determine movements and home range size. A summary of first-year movements of each deer instrumented in January and February, 1987, through March 4, 1988, and reports received about locations of eartagged (only) deer is presented. Movements of up to 145 and 82 airline km, respectively, were recorded for whitetails and mule deer. More locations are needed for calculation of home range size. ��13 DEVELOPMENT OF CENSUS METHODS FOR DEER IN PLAINS RIVERBOTTOM HABITATS Roland C. Kufeld P. N. OBJECTIVES 1. To determine seasonal movements and home range size of mule and whitetailed deer in plains riverbottom habitats. 2. To develop and test methods for estimating size of deer populations in plains riverbottom habitats. SEGMENT OBJECTIVE To determine seasonal movements and home range size of mule and white-tailed deer in plains riverbottom habitats. ACKNOWLEDGMENTS David North and numerous personnel from Colorado Division of Wildlife Northeast Region and Game Research Section were instrumental in capturing deer. STUDY AREA The study area is the South Platte River basin extending from Greeley, Colorado, to Nebraska. Riparian vegetation in the floodplain is dominated primarily by cottonwood (Populus sargentii), and willow (Salix spp.). The riverbottom is bordered along much of its length by agricultural lands, mainly cornfields. Other stretches are bordered by rangelands dominated by mixed prairie or sand sagebrush (Artemisia fililolia) (Costello 1954). Land status includes both private lands and state-owned wildlife areas. Results from the South Platte should apply to most other plains riverbottom habitats such as those found along the Arkansas River. METHODS AND MATERIALS Mule and white-tailed deer were trapped and marked in the South Platte riverbottom between Gilcrest and Sedgwick, Colorado, during the period January 6February 11, 1988. Most adult does and each adult buck received a radiocollar and 2 orange, numbered eartags. Deer were captured in Clover traps (Clover 1956) and a drop net. Each trap was baited with alfalfa hay and eared corn. The drop net was baited with hay, corn, and apple pulp. Adult white-tailed and mule deer, radio-collared during January and February, 1987 (Kufeld 1987), were located at approximately 2-week intervals throughout the segment. Those deer instrumented in Jqnuary and February, 1988, were located at about 2-week intervals beginning February 2, 1988. �14 RESULTS AND DISCUSSION Seventy-four deer were captured and marked in 1988, of which 24 adults (11 mule deer and 13 whitetails) were radio-collared (Tables 1 and 2). The following is a summary of first-year movements of 12 adult radio-collared whitetails, 13 adult radio-collared mule deer, and reports received about 43 other deer with only eargags from date of capture in January-February, 1987, along the South Platte River in eastern Colorado, through March 4, 1988. As of March 4, 1988, reports have been received on 11 of the 43 eartagged (only) deer. Five were reported shot by hunters, 2 were found dead, and 4 were observed alive. Of 6 adult radio-collared bucks, 1 mule deer and 2 whitetails were legally killed by hunters, and 1 mule deer was poached. The other 2 (1 mule deer and 1 whitetail) were still alive on March 4, 1988. Ten adult mule deer does and 9 adult white-tail does were radio-collared. One adult doe of each species was killed by an automobile. None were shot by hunters or died of other causes. During the first year, some individual bucks and does of both species made relatively long movements from their trapsites, while others stayed fairly close to their point of capture. Movements of up to 145 and 82 airline km, respectively, were recorded for whitetails and mule deer. RADIO-COll.ARED DEER White-tail Bucks (all tagged as adults) Eartag No. 28. Frequency 149.660. Caught 1-22-87 1.6 km west of Hardin Bridge. This deer stayed in or near the riverbottom and ranged from 9.7 river km ups t ream to 6.4 river km downstream of its trapsite through 3-4-88. Eartag No. 39. Frequency 149.770. Caught 2-3-87 1.6 km east of Merino Bridge. This deer stayed in or near the riverbottom and ranged from 4.8 river km upstream to 17.7 river km downstream of its trapsite. It was legally shot 12-3-87 6.1 km downstream of its trapsite. When shot, its antlers had 4 points on each side. Eartag No. 42. Frequency 149.780. Caught 2-3-87 5.6 km east of Hardin Bridge. Between 2-3-87 and mid-June, 1987, the deer stayed in the riverbottom in an area from 5.6 river km upstream to 2.4 river km downstream of its trapsite. In mid-June, 1987, it moved to an area centered about 9.7 airline km NW of Jackson Reservoir. It stayed within 1.6 km of that spot until mid-September. That area was treeless country with grassland, wheatfields, and some sorghum fields. The approximate center of this area was 27.4 airline km from its trapsite and 16.9 km from the Platte River. It stayed within about 1.6 km of the approximate center of the area until mid-September. Then it returned to the trapsite vicinity and occupied the same segment of riverbottom it used from 2-3-87 to mid-June of 1987. It was legally shot by a hunter on 12-13-87 within 0.6 km of the river and 2.4 km west of its trapsite. When shot, its antlers had 5 x 6 points. White-tail Does (all tagged as adults) Eartag No.8. Frequency 149.511. Caught 1-19-87 1.6 km west of Weldona Bridge. In late February, 1987, the deer moved 23.3 river km upstream to a site about 4.0 river km upstream from Orchard Bridge. It occupied a very �15 small area in the riverbottom there (about 1.9 km) until about 9-1-87. On 9-12-87 it was located at Goodrich, on 9-25 at Sterling, and on 10-13 it was in the riverbottom at the east end of the Bravo State Wildlife Area east of Sterling. This represented a movement of 121 river km downstream between 9-1 and 10-13. Between late October and 3-4-88, it stayed in the riverbottom between Dune Ridge Wildlife Area and Sterling. Eartag No. 16. Frequency 149.538. Caught 1-20-87 6.4 km east of Atwood Bridge. The deer stayed near the riverbottom and ranged from 2.4 river km upstream to 2.4 river km downstream of its trapsite until 7-10-87, when it was hit by a car and killed. Eartag No. 35. Frequency 149.731. Caught 2-3-87 4.0 km east of Merino Bridge. Between 2-3-87 and late August, 1987, the deer stayed in the riverbottom and ranged from the trapsite to 5.6 river km upstream. In late August, 1987, it became entangled in a barbed wire fence and slipped off its collar. Thus, it could no longer be radio tracked, but it is assumed its eartags remain intact. Eartag No. 36. Frequency 149.741. Caught 2-3-87 1.6 km east of Merino Bridge. This deer stayed in the riverbottom from 2-3-87 through 3-4-88. Except for 1 location on 4-18-87, which was 10.3 river km upstream from its trapsite, it remained in an area between 3.2 river km upstream and 1.6 river kID downstream of its trapsite. Eartag No. 43. Frequency 149.791. Caught 2-3-87 5.6 miles east of Hardin Bridge. From 2-3-87 until 4-17-87 the deer stayed in the riverbottom from 6.4 river km'upstream to 1.6 river km downstream of its trapsite. Sometime between 4-17 and 5-4 it left that area and spent the summer at an unknown location, which was apparently far from its trapsite. In addition to scanning its frequency on all regular flights to locate radio-collared deer, we made a special flight just to locate this deer. The flight route was down the South Platte River from Greeley to Julesburg, 48 km north of the river back to Greeley, 48 km south of the river to south of Brush, up Bijou Creek to Colorado Springs, then to Denver, Greeley, and Fort Collins. No signal was received during the flight. Sometime between August 27 and September 12 the deer returned to the trapsite vicinity. Between 9-12-87 and 3-4-88 it stayed in the riverbottom from 2.4 river km upstream to 4.0 river km downstream of its trapsite, except on 10-27-87 when it was located 22.5 river km downstream from its trapsite near the town of Orchard. Eartag No. 44. Frequency 149.800. Caught 2-4-87 1.6 km east of Merino Bridge. Between 2-4-87 and 5-4-87 the deer stayed in the riverbottom in an area from 0.8 river km upstream to 2.4 river km downstream of its trapsite. On 5-15 it was located at the southwest end of Prewitt Reservoir (11.3 airline km from its trapsite), and on 6-4 it was located about 6.4 km south and 1.6 km east of Woodrow, which is about 60 km from its trapsite and about 39 airline km south of the Platte River. The site was far out on the plains in an area of wheatfields and pastureland. A small creek (Beaver Creek) lined with willows, making a riparian zone only about 3 to 6 m wide, traversed the area. The deer stayed within 2.4 km of this site through 3-4-88 �16 Eartag No. 46. Frequency 149.809. Caught 2-4-87 5.6 km east of Hardin Bridge. Between 2-4-87 and 5-15-87 the deer stayed in the riverbottom from 2.4 river km upstream to 1.6 river km downstream of its trapsite. On 6-4-87 it was located near Banner Lakes Wildlife Area, 33.8 airline km from its trapsite. This is also 33.8 km from the Platte River. It stayed in that area until early August, when it returned to the vicinity of its trapsite. Between 8-18-87 and 3-4-88 it stayed in the Platte riverbottom from the trapsite to 3.2 river km downstream, except that on October 27 it was located 12.9 river km downstream from its trapsite. Eartag No. 62. Frequency 149.921. Caught 2-13-87 3.2 km east of Fort Morgan Bridge. This deer stayed in or within 0.4 km of the riverbottom and from 9.7 river km upstream to 2.4 river km downstream from its trapsite from 2-13-87 through 3-4-B8. Eartag No. 64. Frequency 149.951. Caught 2-17-87 4.0 km east of Masters Bridge. This deer stayed in the riverbottom from 0.8 river km upstream to 0.8 river km downstream of its trapsite between 2-17-87 and 5-15-87. On 5-30 it was located at the south end of Empire Reservoir, 7.2 airline km from its trapsite and 7.2 airline km from the river. It stayed in that area until the first week in August, when it returned to the vicinity of its trapsite. Between 8-18-87 and 3-4-88 it stayed in the riverbottom in an area 0.8 river km above to 0.8 river km below its trapsite. Mule Deer Bucks (all tagged as adults) Eartag No. 25. Frequency 149.641. Caught 1-21-87 at Hardin Bridge. Between 1-21-87 and 3-4-88 this deer remained in or near the riverbottom and ranged from 6.4 river km upstream to 0.8 river km downstream of its trapsite. During the fall of 1987, its antlers had 4 points on each side. Eartag No. 26. Frequency 149.651. Caught 1-21-87 at Hardin Bridge. Between 1-21-87 and 5-30-87 it ranged within 1.6 km of the riverbottom and from its trapsite to 4.0 river km downstream of its trapsite. On 5-30-87 it was located about 20.1 airline km south of Kersey and about 20.9 airline km from the Platte River. It stayed in that general area until last located on 10-28-87 12.9 km south and 3.7 km east of Kersey. It was killed illegally between 10-28, after 2:28 PM, and 11-9; and the collar was thrown in a pond 8.4 km south and 0.6 km east of La Salle. When last seen, its antlers had 4 points on each side. Eartag No. 33. Frequency 149.701. Caught 2-2-87 1.6 km east of Weldona Bridge. Between 2-2-87 and 10-24-87 this deer stayed within about 1.6 airline km of the riverbottom and ranged from 0.8 river km upstream to 2.0 river km downstream of its trapsite, except for 2 trips of short duration outside that area. On 3-6-87 it was located in the riverbottom 8.9 river km downstream from its trapsite, and on 5-15-87 it was located in Bijou Creek 7.2 airline km from its trapsite and 7.2 airline km from the South Platte River. It was shot by a hunter on 10-24-87. It was a very large buck, and when killed, its antlers had 7 x 6 points. Mule Deer Does (all tagged as adults) Eartag No. 12. Frequency 149.521. Caught 1-9-87 at Hardin Bridge. Between 1-19-87 and 3-4-88 this deer stayed in the riverbottom and ranged from its trapsite to 5.6 river km upstream from its trapsite. �17 Eartag No. 13. Frequency 149.531. Caught 1-19-87 at Hardin Bridge. Between 1-19-87 and 3-4-88 this deer stayed in the riverbottom and ranged from 4.8 river km upstream to 4.8 river km downstream from its trapsite. Eartag No. 22. Frequency 149.551. Caught 1-20-87 at Hardin Bridge. Between 1-20-87 and 3-4-88 this deer stayed within 3.2 km of the riverbottom and ranged from 1.6 river km upstream to 3.2 river km downstream of its trapsite. Eartag No. 23. Frequency 149.631. Caught 1-20-87 at Hardin Bridge. Between 1-20-87 and 5-20-87 this deer stayed in the riverbottom and ranged from 3.6 river km upstream to 4.5 river km downstream of its trapsite. On 5-30-87 it was located at Lord Reservoir, 3.2 km south and 5.6 km east of Keenesburg. This was 30.9 airline km from its trapsite and 27.4 airline km from the Platte River. It stayed within 1.6 km of Lord Reservoir during the summer and was still there on 10-13-87. On 10-27-87 it was located back in the Platte River near its trapsite. Between 10-27-87 and 3-4-88 it stayed in the riverbottom and ranged from 4.5 river km to 1.3 river km upstream of its trapsite. Eartag No. 29. Frequency 149.671. Caught 1-22-87 at Hardin Bridge. Between 1-22-87 and 3-4-88 this deer stayed in the riverbottom and ranged from 4.2 river km upstream to 1.6 river km downstream of its trapsite. Eartag No. 48. Frequency 149.859. Caught 2-9-87 3.2 km east of Orchard Bridge. On 2-9-87 and 3-6-87 it was located in the Platte riverbottom 2.9 river km upstream from its trapsite. On 3-18-87 it was located 3.2 airline km west of Jackson Reservoir and about 5.6 airline km from the Platte River. It stayed away from the river and lived on the western and southern sides of Jackson Reservoir until 3-4-88 except for 1 location on 12-7-87 when it was found at its trapsite in the riverbottom. Eartag No. 50. Frequency 149.839. Caught 2-12-87 1.6 km west of Hardin Bridge. Between 2-12-87 and 3-4-88 this deer stayed within 1.6 km of the river and ranged from 1.6 to 7.7 river km upstream of its trapsite. Eartag No. 57. Frequency 149.869. Caught 3.2 km east of Orchard Bridge. This deer was trapped in the riverbottom but soon left. On 2-23-87 it was located at the northwest corner of Jackson Reservoir. This was 7.7 airline km from its trapsite and 7.7 airline km from the river itself. From the time it left shortly after being caught through 3-4-88, it never returned to the river. It stayed in an area extending about 6.4 km to the west and north of the northwest corner of Jackson Reservoir. Eartag No. 61. Frequency 149.889. Caught 2-12-87, 1.6 km west of Hardin Bridge. Between 2-12-87 and 3-4-88 this deer stayed within 1.6 km of the river and ranged from its trapsite to 6.1 river km upstream. Eartag No. 67. Frequency 149.970. Caught 2-17-87 at Hardin Bridge. Between 2-12-87 and 6-30-87 the deer stayed in the riverbottom and ranged from 6.0 to 0.8 river km upstream from its trapsite. On 7-16-87 it was located in a cornfield about 1.6 km southwest of its trapsite and about 1.6 km from the river. It stayed in cornfields in that area until it was killed by an automobile on US 34 4.8 airline km from its trapsite and 3.2 airline km from the river about 8-1-87. �18 EARTAGGED (ONLY) DEER White-tail Bucks (all tagged as fawns) Eartag No.3. Caught 1-19-87 1.6 km east of Cooper Bridge (Hillrose). This deer was shot by a hunter on 10-1-87 4.8 km east of Meridan, Wyoming. This was about 145 airline km from its trapsite. Eartag No. 45. Caught 2-4-87 5.6 km east of Hardin Bridge. This deer was shot by a hunter on 12-5-87 in the Platte riverbottom about 3.9 river km downstream from Masters Bridge and 16.1 river km downstream from its trapsite. Eartag No. 63. Caught 2-13-87 3.2 km east of Fort Morgan Bridge. This deer was found dead in a roadside ditch on 10-16-87. It had been dead about a month. The spot was 6.4 km miles southeast of Gill, which is 82 river km upstream from its trapsite and 2.8 airline km north of the Platte River. White-tail Does (all tagged as fawns) Eartag No. 15. Caught 1-20-87 6.4 km east of Atwood Bridge. It was observed on 3-18-87 1.6 km east of Merino Bridge. This is 16.1 river km upstream from its trapsite. Eartag No. 31. Caught 2-2-87 1.6 km east of Merino Bridge. This deer was shot by a hunter on 12-1-87 near its trapsite 1.6 km east of Merino Bridge. Eartag No. 41. Caught 2-3-82 3.2 km east of Fort Morgan Bridge. observed 12-15-87 1.6 km east of its trapsite. It was Eartag No. 60. Caught 2-11-87 at Hardin Bridge. It was found dead in a field 0.8 km east of Jackson Reservoir on 12-4-87. It had been dead for several weeks. The site where found was about 33.8 airline km east of the trapsite and 4.8 airline km north of the South Platte River. Mule Deer Bucks (all tagged as fawns) Eartag No. 51. Caught 2-10-87 1.6 km east of Weldona Bridge. On 7-8-87 this deer was observed 4.0 km east of Nunn. This is approximately 82 airline km northwest of its trapsite and about 37 airline km north of the South Platte River. Eartag No. 65. Caught 2-13-87 3.2 km east of Orchard Bridge. This deer was observed on 4-25-87 1.6 km southwest of Jackson Reservoir and about 4.8 airline km northwest of its trapsite. On 10-18-87 it was killed by a hunter about 4.8 km west of Grover, which was about 59.5 airline km north of its trapsite and 59.5 airline km north of the South Platte River. Mule Deer Does (all tagged as fawns) Eartag No. 53. Caught 2-10-87 at Hardin Bridge. On 12-6-87 this deer was observed 6.4 km north of Black Hollow Reservoir. This is approximately 49.9 airline km northwest of its trapsite and about 37 airline km northwest of the South Platte River. �19 Eartag No. 55. Caught 2-10-87 at Hardin Bridge. On 12-3-87 this deer was shot by a hunter 4.2 km east and 5.6 km north of Galeton. This is approximately 26.6 airline km north-northwest of its trapsite and about 17.7 airline km north of the South Platte River. LITERATURE CITED Clover, M. R. 1956. Single-gate deer trap. Calif. Fish and Game 42:199-201. Kufeld, R. C. 1987. Development of census methods for deer in plains riverbottom habitats. Colo. Div. Wildl., Wildl. Res. Rep. July (1):13-19. Prepared by ~f-;-~_';--:'- ~~-:;(--::C:--:;--,-_;t&_·.,_t~_/ _;_._' __ Roland C. Kufeld Wildlife Researcher C �20 Table 1. Mule and white-tailed deer trapped and marked in the South Platte riverbottom between Gilcrest and Sterling, Colorado, during 1-6-88 through 2-11-88. -----------------------------------------------------------------------------.Species Sex Age Radio collared and eartagged Eartagged only Total ------------------------------------------------------------------------------ Mule deer Whi tetai 1 buck adul t fawn 4 0 0 9 4 9 doe adul t fawn 7 4 9 11 0 adult fawn 5 0 0 5 13 13 adul t fawn 8 0 24 5 10 13 10 74 buck doe TOTAL 50 9 �21 Table 2. Deer tagged along South Platte River between Platteville through 2-11-88. and Julesburg, Colorado, 1-6-88 -------------------------------------------------------------------------------------------------------Eartag Age when number Species Sex captured Date captured Capture 1ocati on Radioco11ar attached 1 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge 2.S mi. E. of Merino Bridge 2.5 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge 1 mi. W. of Proctor Bridge 1 mi. W. of Proctor Bridge 1 mi. W. of Proctor Bridge 1 mi. W. of Red Lion Bridge 2 mi. E. of Red Lion Bridge 2 m1. E. of Red Lion Bridge 2 mi. E. of Atwood Bridge 2.S mi. E. of Merino Bridge 2.5 mi. E. of Merino Bridge 2.5 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge 1 mi. W. of Red Lion Bridge 1 mi. E. of Merino Bridge 2 mi. E. of Red Lion Bridge 2 mi. E. of Red Lion Bridge 2 mi. E. of Red Lion Bridge 1 mi. W. of Proctor Bridge 2 m1. E. of Red Lion Bridge 2 mi. E. of Red Lion Bridge 1 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge 1 mi. Eo of Heri no Bri dge 2 mi. E. of Atwood Bridge 1 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge 1 mi. W. of Proctor Bridge 2.5 mi. E. of Merino Bridge 1 mi. W. of Proctor Bridge 1 mi. E. of Merino Bridge 1 mi. w. of Proctor Bridge 1 mi. w. of Proctor Bridge 1 mi. W. of Proctor Bridge 1 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge 1 mi. E. of Merino Bridge Hardin Bridge 1 mi. W. of Hardin Bridge 1 mi. W. of Hardin Bridge Hardin Bridge 2.5 mi. E. of Masters Bridge 3.5 mi. W. of Evans Bridge Hardin Bridge 1. 5 mi. E. of Greeley Airport 2.5 mi. E. of Masters 8ridge 2.5 mi. E. of r~asters Bri dge 2.5 mi. E. of Masters Bridge Masters Bridge 2.5 mi. E. of Mas ters Bridge Masters Bridge 2.5 mi. E. of Masters Bridge Masters Bridge Masters Bridge 2.5 mi. E. of Masters Bridge Hardin Bridge 3.5 mi. W. of Evans Bridge 2.5 mi. E. of Masters Bridge 2.5 mi. E. of Masters Bridge Masters Bridge 2.5 mi. E. of Masters Bridge 2.5 mi. E. of Masters Bridge 3.5 mi. W. of Evans Bridge 149.361 149.262 -------------------------------------------------------------------------------------------------------70 whitetail buck adult 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 90 91 92 93 94 95 96 97 98 99 100 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 151 152 153 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 whitetail whi teta il whitetail whitetail whitetail whitetail mule deer mule deer mule deer whi teta il mule deer mule deer whi te te i1 whitetail whitetail whitetail whitetail whitetail whi teta il whitetail mule deer mule deer mule deer mule deer mule deer whi tetai 1 whi tetail whitetail whi tetail whitetai 1 whi tetail whteitail whi tetail whitetail mule deer whi tetail mule deer whitetail mule deer mule deer mule deer whi tetai 1 whi teta il whitetail whi tetail whitetail whi tetail mule deer mule deer mule deer mule deer whi tetai1 mule deer mule deer mule deer mule deer whitetai 1 mule deer whitetail whitetai 1 whi teta il mule deer whitetail mule deer mule deer mule deer mule deer whi tetai 1 whitetail mule deer mule deer mule deer mule deer doe doe buck doe doe buck buck doe doe doe doe doe buck doe buck doe doe doe buck doe doe doe doe buck doe doe buck buck doe doe doe doe buck doe buck doe buck buck doe doe doe buck doe buck doe buck doe buck buck doe buck buck buck buck buck doe doe doe doe buck buck buck buck doe doe doe buck doe buck doe doe doe buck adult fawn fawn adult fawn adult adult adult fawn adult adult adult fawn adult fawn fawn adult adult fawn adult fawn adult adult fawn fawn fawn fawn fawn fawn adult fawn fawn fawn fawn fawn adult fawn fawn fawn fawn adult fawn adult adu1 t fawn adult fawn fawn fawn adult fawn fawn adult fawn adult adult adult adult adult fawn adult fawn fawn fawn adult adult fawn adu1 t fawn fawn fawn adult adult 1-18-88 1-18-88 1-18-88 1-18-88 1-18-88 1-18-88 2- 3-88 1-18-88 1-18-88 1-18-88 1-18-88 1-18-88 1-18-88 1-20-88 1-20-88 1-20-88 1-20-88 2- 5-88 1-20-88 1-20-88 1-21-88 1-21-88 1-21-88 1-21-88 1-22-88 1-22-88 1-22-88 1-20-88 1-26-88 1-27-88 1-28-88 1-18-88 1-29-88 1-29-88 1-29-88 1-29-88 1-18-88 2- 3-88 2- 5-88 2- 5-88 2- 5-88 2- 5-88 2-11-88 1-27-88 1-18-88 2-11-88 2-11-88 2-11-88 1-11-88 1-11-88 1-12-88 1- 9-88 1- 9-88 1-11-88 1-11-88 1-11-88 1- 7-88 1- 7-88 1- 7-88 1- 7-88 1- 7-88 1- 6-88 1- 6-88 1- 7-88 1- 6-88 1- 6-88 1- 8-88 1- 8-88 1- 8-88 1- 8-88 1- 8-88 1- 8-88 1- 8-88 1-13-88 149.252 149.370 149.382 149.291 149.282 149.538 149.651 149.971 149.271 149.351 149.390 149.731 149.431 149.452 149.332 149.301 149.341 149.311 149.411 149.321 149.780 149.461 -------------------------------------------------------------------------------------------------------- ��Colorado Division of Wildlife Wildlife Research Report July 1988 23 JOB FINAL REPORT State of Colorado Project No. W-153-R-2 -----------------------No. 2 ---------------------- Work Plan Job No. 10 Period Covered: Author: Mammals Research Deer Investigations Compensatory Mortality in Mule Deer Populations July 1, 1987 - June 30, 1988 R. M. Bartmann Personnel: T. A. Abbott, L. H. Carpenter, B. T. Helmich, J. S. Osborn, L. Renner, T. D. Schnurr, W. F. Tysinger, D. L. Weybright, E. Weber, and G. C. White ABSTRACT Three pastures at the Little Hills Wildlife Area were stocked with mule deer to simulate removal rates of 0, 33, and 66%. Forty-five to 47 radio-collared fawns were placed in each pasture along with enough adults to achieve target densities. No fawns in the high density pasture survived. Eleven and 15% of the fawns in the low and medium density pastures, respectively, survived. Snow cover that persisted into late March may be partly responsible for the similarity in survival rates in these pastures. ��25 COMPENSATORY MORTALITY IN MULE DEER POPULATIONS Richard M. Bartmann P. N. OBJECTIVES To estimate the degree of compensatory winter mortality forces operating within the mule deer fawn age class in Piceance Basin. SEGMENT OBJECTIVES 1. Stock 50 radio-collared fawns plus enough uncollared adults in each of three pastures at the Little Hills Wildlife Area to achieve three different deer densities. 2. Monitor radio-collared fawns for mortality 5-7 days per week throughout winter and identify cause of death for each mortality. The study is divided into two parts: a field experiment and a pasture experiment. The field experiment is the primary responsibility of cooperators at Colorado State University, and the pasture experiment is the primary responsibility of the Division of Wildlife. Therefore, only the pasture experiment is reported here. METHODS AND MATERIALS Three pastures at the Little Hills Wildlife Area were stocked in late November and early December with deer trapped in the immediate area. Target densities for pasture stocking were 44, 89, and 133 deer/km2 which simulated removal rates of 67, 33, 0%, respectively. Fifty fawns were put fawn was weighed and adults were added to were neither weighed in each pasture for estimation of survival rates. Each radio collared before being placed in a pasture. Enough each pasture to attain the target densities, but they nor marked in any way. Fawn radio collars contained a motion-sensor set with a 4-hour delay to enable detecting mortalities. Radio signals were monitored 5-7 days per week during winter and all mortalities checked for cause of death as soon as possible. In the spring when deer started to migrate, gates in all pastures were opened and the deer allowed to leave voluntarily. Monitoring for suvival continued at 2-week intervals until June 15, 1988. RESULTS Pasture stocking occurred from November 9 through December 5, 1988. Several early deaths in each pasture reduced the number of fawns available for survival rate estimates (Table 1). ��27 Table 1. Stocking summary for 3 pastures at the Little Hills Wildlife Area during winter 1987-88. . ------------------------------------------------------------------------------Stocking densi tya Low t~ediurn High Number of deer Fawns Adults M F M F 23 20 24 27 23 22 2 8 5 27 36 36 Fawn:adu1t ratio 162:100 109:100 112:100 Pasture size Hectares Acres 170 101 66 aStocking densities simulate removal rates as follows: Medium = 33%, and High = 0%. Deer/area km2 mi 2 419 249 45 91 116 237 162 132 344 Low = 67%, Table 2. Fate of mule deer fawns stocked at 3 removal rates in patures at the Little Hills Wildlife Area during winter 1987-88. Percentages are in parentheses. Removal rate (%) 67 33 o Starvati on 47 47 45 40 (85) 39 (83) 43 (96) Mortal ity Unknown 2 (4) 1 (2) 2 (4) Total 42 40 45 (89) (85) (100) Survived 5 (11) 7 (15) (0) o ��Colorado Division of Wildlife Wildlife Research Report July 1988 29 JOB PROGRESS REPORT State of Colorado Project No. W-153-R-2 -----------------------No. 2 --~--------------- Work Plan Job No. 11 Period Covered: Author: Mammals Research Deer Investigations Testing of Mule Deer Census Methodology July 1, 1987 - June 30, 1988 R. M. Bartmann Personnel: L. H. Carpenter, D. L. Weybright, and G. C. White ABSTRACT Three line transect surveys were completed in the pastures during November and December, 1987. A paper entitled, "Estimating l1ule Deer Densities in PinyonJuniper Woodland Using Aerial Line Transects" was submitted to The Journal of Wildlife Management. ��31 TESTING OF MULE DEER CENSUS METHODOLOGY Richard M. Bartmann P. N. OBJECTIVES 1. Conduct three areial line transect surveys during the stocking process at the Little Hills Wildlife Area to estimate deer numbers at three density levels. 2. Compare true deer densities with estimated densities generated by five line transect estimators to determine which is most efficient. 3. Analyze data and publish results in The Journal of Wildlife Management. SEGMENT OBJECTIVES Same as P. N. Objectives. RESULTS Three line transect surveys were completed in the pastures during November and December, 1987 •. A paper entitled, "Estimating Mule Deer Densities in PinyonJuniper Woodland Using Aerial Line Transects" was submitted to The Journal of Wildlife Management. -: Prepared by / ~ "M--- /~/{~ ~hard M. Bartmann Wildlife Researcher C - ��33 Wildlife Research Report July 1988 JOB PROGRESS REPORT State of Colorado Project No. W-153-R-2 -----------------------No. 3 ---------------------- Work Plan Mammals Research Elk Investigations Job No. 2 Period Covered: July 1, 1987 - June 30, 1988 Author: Trapping, Transporting, and Maintenance of Elk at Livestock-Elk Grazing Study G. D. Bear Personnel: D. Baker, T. Hobbs, M. Miller, D. Haskins, T. Lines, C. Reichert, J. .Nad Lson , J. Papez, B. Dupire, C. Woodward, J. Haskins, M. Bauman, K. Navo ABSTRACT A total of 154 elk was trapped at locations near Meeker, Craig, and Maybell to stock the experimental pastures on the Little Snake River Wildlife Area north of Maybell, Colorado. Pastures were stocked with 54 adult females in December and January; the elk were removed from the pastures in mid-April. Snow accumulations persisted in the pastures throughout the winter making it difficult for the elk to forage. Eleven elk died of malnutrition (10 in "high-use pastures" and 1 in a "low-use pasture") and had to be replaced. Average weights of 51 elk calves at the Meeker, Craig, and 11es Grove trapsites were: 253, 255, and 238 lbs, respectively. ��35 TRAPPING, TRANSPORTING, AND MAINTENANCE OF ELK AT LIVESTOCK-ELK GRAZING STUDY G. D. Bear P. N. OBJECTIVE To provide assistance to the Livestock-Elk Grazing Study near Maybell, Colorado, by capturing and maintaining an experimental elk herd. SEGMENT OBJECTIVE 1. To trap, mark, stock, and maintain 54 adult female elk in the livestockelk grazing pasture complex during the period December 15 to April 20. 2. To determine seasonal movements of radio-collared elk after they are released from the pastures. METHODS AND RESULTS Capturing and Handling of Elk Trapsites were established at the following sites: (1) northeast of Craig (5 mi east of Ralph White Reservoir near the Don Cook Ranch; (2) southwest of Hamilton (1 mi south of lIes Grove in Axial Basin); (3) 4 mi southeast of Meeker near the Environmental Plant Center; (4) south of Lay at the junction of ~organ Gulch and Moffat Co. Road 17; (5) 15 mi north of Maybell at Godiva Rim; and (6) southwest of Hayden. Portable group-traps baited with alfalfa hay and salt were used to capture elk. Details for handling elk at the trapsites and in the corral at the livestock-elk grazing pasture complex are presented in the previous Federal Aid Report. A total of 144 elk were captured from December 9, 1987, through January 14, 1988, to meet the stocking quota (54 adult female elk) for the experimental pastures (Table 1). An additional 10 adult female elk were trapped in late January through mid-February and maintained at the pasture corrals for substituting in experimental pastures as needed (Table 3). Calf elk were weighed at the trapsites before they were released. A platform scale was used to obtain the weights. Average weight of calves at the Meeker, Craig, and lIes Grove sites were: 253, 255, and 238 lbs, respectively (Table 2). Average weight of the lIes Grove site was slightly lower than average weights for calves at the other sites, however, this difference was not significant (P = .05). Elk in the Pastures Stocking experimental pastures with elk at the Little Snake Study Area proceeded on schedule during December and January, 1987-88. Average stocking date was January 4, 1988. All animals released into pastures tested negative for serologic evidence of exposure to brucellosis and to 5 serovars of leptospirosis. �36 Weather conditions during the 1987-88 winter were very difficult for elk in the pastures. This was in marked contrast to 1986-87, which had very light snow accumulations. There was very little snow in early December, then a series of storms in late December and January resulted in 4-6 ft snow drifts in the low areas of the pastures and 6-12 in of snow on the ridgetops. Air temperatures ranged from -15 to -400F at night and only a maximum of l5-250F during the daylight hours in January through February. Due to these low temperatures, there was not a noticeable decrease in the snow accumulations during those months. The elk were forced to paw for food, even on the ridgetops. After February 20 thre was a week of sunny weather with daytime temperatures at 38-400F, which opened holes in the snow cover. By February 26 there was an estimated 30-50% bare ground (mostly on the ridge- tops). On March 10-11 a storm with extremely strong winds left 6-12 in of snow drifted across the pastures. Only 10% of the pastures (ridges) were free of snow cover. Another severe storm was in the area on March 16; again making it very difficult for the elk to secure food. The snow cover was 90% melted by March 22. In late March new growth on Poa was approximately 1 in tall; Stipa, Agropyron, and Festuca were showing green shoots at the base. Severe weather conditions in January and February, then again in mid-March, severely stressed the elk. Nine elk died of malnutrition from January 25 to February 27; then an additional elk died on April 1 and April 12. The elk that died April 1 was in a "low-use pasture" while the remaining 10 were in the "high-use pastures" (3 cows in #2, 5 cows in #5, 2 cows in #9, and 1 cow in #11). All were replaced with animals held in the corrals. Animals crossed the electric fences at an accelerated rate last winter. Ten elk moved through the fences and were returned to their pastures. It is speculated that snow insulated the animals, thus reducing the electrical shock they received when attempting to push between the wires. Deer readily crossed fences (exceeding 20 crossings) and made it difficult to keep them cleared from the pastures. Only 1 antelope crossed the fence into the pastures during the 1987-88 winter. Elk were removed from the experimental pastures during the week of April 15 to April 21. Thirty of them were transported to Little Hills Experiment Station, near Meeker, Colorado; while the remaining ones were released at the site. Elk at Little Hills are to be maintained in a 360-acre pasture until next winter, when they will again be taken back to the Little Snake River Experimental Pastures. Elk Movements Minimal effort was conducted on this aspect of the study. Over half of the elk were moved to the Little Hills pasture and many of the elk released at the study site were in poor condition. It was thought that the added stress of collaring the elk would be detrimental, so they were released uncollared. Two cows radio collared the previous year returned to the Godiva winter range in January and left during the first week in April. '- 0) Prepared by ~~~~ ~~LJ~~~~ Geo~Wildlife Researcher _ �37 Table 1. Summary of elk trapped during the period December 9,1987, January 14, 1988.* Cows Yearlings Ferna1e r~a1e Calves Female Nale through Bull s Total ------------------------------------------------------------------------------Meeker NE Craig 11es Grove Morgan Gulch Total 14 8 22 15 59 1 3 3 1 8 2 0 4 1 3 20 1 4 6 29 13 9 19 0 41 0 1 0 0 1 34 22 67 144 ------------------------------------------------------------------------------*E1k trapped January 28 and February 18 are not included in this summary because adult cows were sorted and all other elk released without sexing or aging. ELK TRAPPING - MOFFAT COUNTY December 9, 1987 - January 14, 1988 Location of Traps Portable-group traps were set at the following locations: (1) northeast of Craig (5 miles east of Ralph White Reservoir near Don Cook Ranch; (2) southwest of Hamilton (1 mile south of Iles Grove in Axial Basin); (3) south of Lay (Morgan Gulch and Moffat Co. Rd. 17), and (4) southeast of Meeker (near Envir. Plant Center). Additional sites were tried south of Hayden and north of Maybell without success. f~arki n9 of E1 k Elk were marked with metal, yellow colored eartags stamped with the DOW Grand Junction Office address and an identification number (86 - prefix). Trapping Crew George Bear Dale Haskins Hi ke Nil 1 er Dan Baker Tom Hobbs Division of Wildlife Tom Lines Chuck Reichert Jeff Madison Joe Papez Barry Dupi re Other Contributors Tim Dole Ramsy Buffham Chip ~lcIntire Don Cook Kris Maneotis Dana McIntire Chuck Wood\'iard Jim Haskins I~ike Bauman Kirk Navo �w co Table 2. Weights of elk calves trapped during the 1987-88 winter. Male Female Both sexes r·1a 1 e Female Both sexes Male Female Both sexes -----------------------------------------------------------------------------------------------------------t-iean Std. dev. Range Number 251 32 187-286 7 258 14 246-274 4 253 26 187-286 11 255 32 208-289 8 250 - - 1 255 30 208-289 9 245 46 153-302 16 229 31 159-268 15 238 40 153-302 31 �39 Table 3. Elk trapped in Moffat and Rio Blanco Counties during Oecember, 19B7, to February 1988. --------------------------------------------------------------------------------------------------Eartag no. Date Sex Age location Remarks --------------------------------------------------------------------------------------------------1 12/9 2 M F 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 12/9 12/9 12/9 12/9 12/9 12/9 12/9 12/9 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/31 12/31 12/31 12/31 12/31 12/31 12/31 12/31 12/31 12/31 12/31 12/31 12/31 12/31 12/31 12/31 12/31 12/31 12/31 12/31 12/31 1/7 57 58 59 60 61 62 63 64 65 1/7 1/7 1/7 1/7 1/7 1/7 1/7 1/7 1/7 M F F M M 66 67 68 69 70 71 72 73 74 75 1/7 1/7 1/7 1/7 1/7 1/7 1/7 1/7 1/8 1/9 F F F M F F F 76 77 78 1/9 1/9 1/9 F 3 4 5 6 7 8 9 10 11 M F F M M F M M M M F F M F M M F F F F F M F M F F F M F F M F F F M F F F M M M F F M F M F ~1 M F M F M F F M F F F F F M F calf adult calf adult adul t calf calf adult yearling yearling calf calf adult adul t calf calf calf calf adult adult adult adult adult calf adult calf calf calf adult calf calf yearling calf adult adult adult calf adult adult calf .calf calf cal f yearling yearling calf adult calf adult adult calf yearling calf calf adult Meeker Meeker Meeker Meeker Meeker ~leker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker Meeker NE Craig NE Crai g NE Craig NE Craig NE Craig NE Craig NE Crai g NE Craig IJE Craig IlE Cra ig NE Crai g NE Craig NE Craig NE Craig NE Craig NE Craig NE Craig NE Craig NE Craig NE Craig NE Craig Iles Grove calf yearling calf calf calf calf yearling adult calf Iles Iles lIes Ll es lIes lIes Iles IIes lIes adult calf adult calf calf calf calf adult adult adult lIes Grove Iles Grove Iles Grove lIes Grove Iles Grove Iles Grove Iles Grove lIes Grove NE Craig lIes Grove yearling calf adult Iles Grove Iles Grove Iles Grove adul t Grove Grove Grove Grove Grove Grove Grove Grove Grove trans. Marvine trans. elk pens trans. Marvine trans. elk pens trans. elk pens trans. Marvine trans. Marvine trans. elk pens released released trans. Marvine - 272 1bs. trans. Marvine - 282 1bs. trans. elk pens trans. elk pens trans. Marvine - 260 1bs. trans. Marvine - 266 lbs. trans. Marvine - 244 1bs. trans. Marvine - 247 1bs. trans. elk pens - RC trans. elk pens - RC trans. elk pens - RC trans. elk pens trans. elk pens trans. Marvine - 255 lbs. trans. e1 k pens trans. Marvine - 276 lbs. trans. Marvine - 247 lbs. trans. Marvine - 246 lbs. trans. elk pens trans. Marvine - 286 lbs. trans. Marvine - 274 lbs. released trans. Marvine - 187 1bs. trans. elk pens trans. elk pens - RC-17l31 trans. elk pens - RC-16740 released - 289 lbs. trans. elk pens - RC-16737 trans. elk pens - RC-17l38 released - 250 lbs. released - 208 lbs. released - 212 lbs. released - 290 1bs. trans. elk pens released - broken incisors released - 244 1bs. trans. elk pens released - 272 1bs trans. elk pens released - 4x4 - 2-yr. old released trans. elk pens released - 276 1bs. trans. elk pens released - 250 lbs. trans. elk pens - RC-3334 died 1/11/88 released - 153 lbs. released released - 208 lbs. released - 254 1bs. released - 178 lbs. released - 241 lbs. released trans. elk pens released - inside of leg injured trans. elk pens - very old released - 232 lbs. trans. elk pens released - 233 lbs. released - 216 lbs. released - 218 lbs. released - 195 1bs. trans. elk pens trans. elk pens - RC-17l48 trans. elk pens - RC-25253 very thin trans. elk pens - RC-23944 released - 275 lbs. trans. elk pens �40 Table 3. - continued --------------------------------------------------------------------------------------------------Eartag no. Sex Date Age Location Remarks --------------------------------------------------------------------------------------------------79 F 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 1/9 1/9 1/9 1/11 1/11 1111 1111 1/11 1/11 1/11 1/11 1/11 1111 1/11 1/11 1/11 1/11 1/11 1/11 1/11 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 1/11 1111 1/11 1/11 1/11 1111 1/11 1/11 1/11 1/11 1/11 1/11 1/11 1/11 1/11 1/11 1111 1/11 1111 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 None None None None None None None None None 1/13 1/13 1/13 1/13 1/13 1/13 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/14 1/28 1/28 1/29 2/18 2/18 2/18 2/18 2/18 2/18 F F F F F F F F F M F F F F F F M M F F M M M M M F M M F F M M M M F F M F F F F M F F F F F F F F F F F F F F F F F F F F M F F F F F F F F F F f calf adult cal f calf adult adult calf adult adult yearling calf calf calf calf calf adult adult yearling calf adult Iles Iles Iles 11es Iles 11es I1es 11es 11es Iles Iles Iles Iles Iles Iles Iles Iles Iles Iles Iles Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove calf calf calf calf calf calf adult calf calf calf adult calf calf yearling calf adult calf calf adul t Iles Iles Iles Iles Iles Iles Iles Iles Iles Iles Iles 11es Iles Iles Iles Iles Iles Iles Iles Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove Grove calf calf adult calf adult adult adult adul t yearl ing adult adult adult adult adul t adult adult calf adult calf adult adult calf calf adult yearl ing adult adult adult adult adul t adult adult adult adult adult adult Iles Grove Iles Grove Iles Grove 11es Grove Iles Grove Iles Grove t10rgan Gul ch Morgan Gulch tiorgan Gul ch Morgan Gulch Morgan Gulch Morgan GulCh Morgan Gulch Morgan GulCh Morgan Gulch Morgan Gulch Morgan Gulch Morgan GulCh t~organ Gul ch Morgan GulCh Morgan Gulch Morgan Gulch Morgan Gul ch Morgan Gulch Morgan Gulch Morgan Gulch Morgan Gulch Morgan GulCh Morgan GulCh Morgan Gul ch Godiva Rim Godiva Rim Godiva Rim Godiva Rim Godiva Rim Godiva Rim released - 260 1bs. trans. elk pens released - 260 lbs. released - 213 lbs. trans. elk pens trans. elk pen s released - 268 lbs. trans. elk pens trans. elk pens trans. elk pens released released released released released trans. elk pens trans. elk pens released released - 286 lbs. trans. elk pens - white eartag '4 released - 271 lbs. released - 290 lbs. released - 251 lbs. released released - 301 lbs. released - 212 lbs. trans. elk pens released - 283 lbs. released - 225 lbs. released - 159 lbs. released - very poor condo released released - 178 lbs. released released - 259 lbs. trans. elk pens - RC-17l49 released - 252 lbs. released - 246 lbs. trans. elk pens - RC-25245 purple eartag '55 released - 214 lbs. released - 230 lbs. trans. elk pens released - 302 lbs. trans. elk pens trans. elk pens trans. elk pens trans. elk pens - RC-171S0 released trans. elk pens trans. elk pens trans. elk pens trans. elk pens trans. elk pens - very old trans. elk pens trans. elk pens released trans. elk pens released trans. elk pens - very old trans. elk pens released released trans. elk pens - very old released trans. elk pens trans. elk pens trans. elk pens trans. elk pens trans. elk pens trans. elk pens trans. elk pens trans. elk pens trans. elk pens trans. elk pens trans. elk pens --------------------------------------------------------------------------------------------------- �co~orado Division of Wildlife Wildlife Research Report July 1988 41 JOB PROGRESS REPORT State of Colorado Project No. W-153-R-2 -----------------------No. 3 ---------------------- Mammals Research Work Plan Multispecies Investigations Job No. 5 Period Covered: July 1, 1987 - June 30, 1988 Author: Impact of Elk Winter Grazing on Livestock Production D. L. Baker Personnel: G. Bear, M. Miller, L. Carpenter, B. Gill, K. Navo, C. Woodward, B. Seely, H. Seely, L. Lovett ABSTRACT All research results for this segment are summarized in the Mammals 2, WP9A,Jl Report. ��Co~orado Division ot Wildlife Wildlife Research Report July 1988 43 JOB PROGRESS REPORT State of Colorado Project No. W-153-R-2 ~~~------------------ Work Plan No. __.....:...3 _ Mammals Research Elk Investigations Job No. 6 Period Covered: July 1, 1987 - June 30, 1988 Author: Effect of Elk Harvest Systems on Elk Breeding Biology D. J. Freddy Personnel: Dr. M. Miller, DVM, D. Hopper, C. Wetherill, M. Cousins, and G. Byrne - Colorado Division of Wildlife; L. Wyman and Wyman Ranch personnel; E. Ryland and Forbes-Trinchera Ranch personnel ABSTRACT Rectal palpation and rectal ultrasound similarly assessed the pregnancy status of elk. Ultrasound, by providing images of fetuses, allowed detection of different sized fetuses and likely different conception dates. Heifercheck blood assays did"not perform well and may have been complicated by low progesterone levels of pregnant elk. Serum progesterone RIAs were more reliable in detecting pregnancy provided threshold values approaching 1 ng/ml for pregnant elk were considered. Reproductive tracts from elk and mule deer were collected on the ForbesTrinchera Ranch. Pregnancy rates for elk were 0% for yearling and 90% for mature cows, and fetal rates were 0.90/mature cow. Fetal sex ratio was 12M:24F which differed from the 17M:6F ratio observed in 1986. Conceptions occurred in the 62-day interval 18 September to 18 November 1987 with 97% of . the concept.Lous occurring in the 33-day interval 18 September to 20 October. Concept.Ions peaked 23 September to 2 Oc t obe r , which .was similar to 1~86. Pregnahcy rates for deer were 0% for yearling and 100% for mature .does, and fetal rates were 1.79 fawns/doe. FetCil sex ratio was 13M: 21F, which differed from 20M:13F ratio observed in 1986. Conceptions occurred in the 19-day interval from 30 November to 18 December 1987 and peaked 6-11 December, 'which was similar to 1986. Most does were in poor body condition when collected in late March, 1988, having kidney fat indexes of 16% and Kistner body condition indexes of 35. -. Reproductive tracts were collected from elk in GMU 33, a portion of the White River elk population. Pregnancy rates were 0% for yearling and 97% for mature cows, and the fetal sex ratio was 20M:15F. Conceptions occurred in the 40-day interval 4 September to 12 October and peaked 18-27 September 1987. ��45 EFFECT OF ELK HARVEST SYSTEMS ON ELK BREEDING BIOLOGY David J. Freddy P. N. OBJECTIVE To evaluate effects of harvest systems on breeding biology of elk. SEGMENT OBJECTIVE Pregnancy test cow elk from the White River (DAU-E6) and Forbes-Trinchera Ranch to compare conception rates in herds with low and high bu11:cow ratios. METHODS AND MATERIALS Large scale pregnancy testing of wild elk in the White River DAU could not be accomplished because of unfavorable trapping conditions. Collections of reproductive tracts from hunter harvests in December, 1987, and January, 1988, provided limited information on pregnancy and fetal rates and conception dates for elk in GMU 33, a portion of the White River DAU. Evaluation of rectal palpation (Greer and Hawkins 1967, Follis 1972), rectal ultrasound (White et a1. 1985), and serum progesterone assays (Weber et a1. 1982, Wood et a1. 1986) to determine pregnancy status continued using captive domesticated elk at the Wyman Elk Ranch near Craig, Colorado, and wild elk on the Forbes-Trinchera Ranch in southern Colorado. Reproductive tracts from both elk and deer were obtained on the ForbesTrinchera Ranch to provide baseline data on pregnancy and fetal rates and estimated conception dates from herds having chronically high bu11:cow and buck:doe ratios. Postseason ratios on the Forbes-Trinchera Ranch in December, 1987, were 34 bu11s:100 cows:56 calves and 46 bucks:lOO does:70 fawns. Comparative ratios for elk in the White River DAU after 3 years of antler-point restrictions were 21 bu11s:100 cows:55 calves. RESULTS AND DISCUSSION Pregnancy Testing Rectal Palpation and Ultrasound On 5 December 1987, 20 female elk on the tvyman Ranch were pregnancy tested. Elk were held in a cattle squeeze-chute, blindfolded, and pregnancy status was determined by rectal palpation and rectal ultrasound. Elk did not generally resist the pregnancy testing. Pregnancy rates were 65% and 67% based on palpation and ultrasound, respectively. The two techniques provided the same results on those elk where both techniques were used (Table 1). One yearling cow and one mature cow that were palpated did not receive an ultrasound scan. The yearling was deemed too small (palpation was difficult), and the mature cow became excited after being palpated. �46 Fetal size was variable, but all fetuses were located within the upper pelvic region of the cow where the ultrasound probe could detect their presence. Fetuses varied in size from about 20 mm in total body length to fetuses having heads 35 mm in length. The differences in fetal size suggested conception dates differed by at least 1 estrus cycle and that ultrasound could be used to judge relative conception dates. The use of ultrasound to judge conception dates appears feasible if conducted in early December as opposed to late January when fetal development and subsequent movement into the abdominal cavity of the cow precludes using ultrasound to judge fetal size (Freddy 1987a). However, even in early December, 4 of 12 fetuses had progressed in their development to the point that they were moving into the abdominal region of the cow where detection by the ultrasound probe would likely have become difficult in a few weeks. Further testing of ultrasound with cows bred on known dates is needed to adequately judge the use of ultrasound to estimate conception dates. Blood Assays The commercial blood progesterone pregnancy testing kit "Heifercheck" (American Diagnostic Sales, Inc., Westport,CT) was evaluated for accuracy using blood obtained from elk at the Wyman Ranch and on the Forbes-Trinchera Ranch. Blood was obtained via the jugular vein of Wyman elk during pregnancy testing. Antlerless elk were harvested by licensed hunters on the Forbes Ranch 12-21 December 1987. Hunters were given blood viles and instructed to collect blood from the chest cavity of their elk shortly after its death and to keep viles copl by placing them in snow, if possible. Blood viles were collected at check stations alQng with the reproductive organs of the elk so pregnancy status was known. Blood collected from Wyman elk was kept cool and centrifuged within 12 hrs and serum was then frozen. Blood from Forbes elk was kept cool and centrifuged within 24 hrs of the animal's death, and serum was then frozen. Heifercheck tests and radioimmunoassays (RIAs) were completed 16 and 18 March 1988, respectively. Four observers simultaneously and independently judged the pregnancy status of Wyman elk using Heifercheck. There were no differences among observers in judging the pregnancy status of elk (X2 [3] ~0.40, ! > 0.50). Observers correctly identified >92% of the 13 pregnant elk but only 43-71% of the 7 nonpregnant elk (Table 2). Five observers similarly judged the pregnancy status of Forbes elk, and there were also no differences among observers (X2 [4] <4.5, P > 0.30). Observers correctly judged 40-77% of the 35 pregnant adult elk, 78-89% of the 9 nonpregnant adult elk, and 40-50% of the 10 nonpregnant' calves (Table 2). These results were discouraging compared to similar, but not true blind tests conducted in 1987 (Freddy 1987a). In 1987 pregnancy status was correctly determined in 100% of 27 Wyman elk, but blood was collected from these elk in late January, 1987, and thus, later in gestation. Pregnancy status was correctly determined in 91% of 23 Forbes elk collected in early December 1986. Most errors were associated with progesterone levels of 1-2 ng/ml, which corresponds to the lower threshold of sensitivity for Heifercheck. The most common error among Wyman elk was judging nonpregnant elk as pregnant (Table 2). All observers incorrectly judged 3 yearlings, and various observers were incorrect on 3 additional elk. RIAs of these 6 females averaged 0.95 + 0.08 �47 (SE) ng/ml (range 0.67-1.23). For Forbes elk, the most common error was judging pregnant elk as nonpregnant (Table 2). RlAs for 11 elk on which nearly all observers erred averaged 2.11 + 0.36 (SE) ng/ml (range 0.75-4.34). Four of the 10 calves were incorrectly judged as pregnant by all 5 observers, and RlAs of these calves averaged 1.85 + 0.56 (SE) ng/ml while RlAs of the 5 calves correctly judged as nonpregnant by all observers averaged 0.76 + 0.46 (SE) ng/ml. Two of the calves on which all observers erred had serum cortisol levels >19 ng/ml suggesting that some calves may have had elevated progesterone levels because of stress from the hunting season (Plotka et ale 1983). Threshold levels of serum progesterone for pregnant wild ungulates have been reported as 2.0 ng/ml for mule deer (Wood et ale 1986), >2 but <3 ng/ml for mountain sheep (Ramsay and Sadleier 1979), and 3.7 ng/ml for elk (Weber et ale 1982). In particular, levels reported by Weber et ale (1982) may have been strongly influenced and elevated by the stress of trapping and drugging their elk with succinylcholine chloride (Wesson et ale 1979). Our data indicate that elk can be pregnant with serum progesterone levels <3 ng/ml. Serum progesterone averaged <3.53 ng/ml for all groups of pregnant adult elk and <O.35ng/ml for all nonpregnant adult elk. Overall ranges of serum progesterone were 0.75-14.86 ng/ml for pregnant and 0.05-1.23 ng/ml for nonpregnant elk (Table 3). Using thresholds of 3, 2, and 1 ng/ml for pregnant adult elk would have resulted in error rates of 43%, 16% and 6% (n = 69); respectively. A threshold of 1 ng/ml would have caused an 9% error rate for nonpregnant adult elk. A threshold value for pregnant elk of 1 ng/ml may therefore be more appropriate than the 3.7 ng/ml proposed by Weber et ale (1982). Summary Rectal palpation and rectal ultrasound both correctly determined pregnancy status of elk. Ultrasound, by providing images of fetuses, allowed detection of different sized fetuses and likely different conception dates. Further testing of ultrasound on pregnant elk with known breeding dates is warranted. Heifercheck blood assays did not perform well and may have been complicted by low progesterone levels of pregnant elk. Serum progesterone RlAs were more reliable in detecting pregnancy provided threshold values approaching 1 ng/ml for pregnant elk were considered. Fetal Collections Forbes Elk Reproductive tracts from 52 female elk were collected by hunters on the Forbes-Trinchera Ranch from 12-14 and 19-21 December 1987. Instructions explaining how to collect the intact uterus and ovaries along with a blood sample and a median incisor were sent via mail prior to the season to all 100 antlerless elk permittees. Reproductive tracts from 3 calves, 7 yearlings, and 42 >2-year females were obtained at check stations by study personnel, usually-within a few hours after elk were harvested. Average age of collected female elk was 4.7 + 0.5 (SE) years with a range of 0.5-16 years (Appendix A). Pregnancy was determined from the presence of fetuses, and rates were 0% for calves, 0% for yearlings, and 90% for cows >2 years old. Unlike 1986, no uteri were judged to be infected and not capable of supporting an embryo �48 (Dr. M. Miller, DVM, pers. comm.). One yearling female may have been reabsorbing an embryo while a 16-year-old female was possibly in the early stages of pregnancy, but both were considered to be nonpregnant. An extremely small embryo was found in a 15-year-old female. There were 38 fetuses observed in reproductive tracts from 49 cows >1 year old. Unlike 1986, no twins were observed. Fetal rates were 0 fetuses/yearling cow and 0.90 fetuses/cow >2 years old. Fetal rates have been lowest for cows aged as yearlings or >13 years and relatively constant for cows 2-12 years old (Table 4). Fetal sex ratios were 12M(33%):24F with 2 of unknown sex. Collecting fetuses approximately 2 wks later in 1987 compared to 1986 aided greatly in determining fetal sex as most fetuses had developed genitalia. Mid-December should be the standard period to collect this data on the Forbes-Trinchera Ranch. Fetal sex ratios differed from unity in both 1986 and 1987 (X2 (1] > 4.00, P < 0.04), differed between years (X2 (1] = 9.2, P = 0.002), but did not differ from unity when pooled among years (X2 (1] = 0.02, P = 0.60)(Table 5). The shift towards female fetuses in 1987 was primarily due to female fetuses accounting for 78% of the fetuses produced by cows 3-6 years old. Conception dates were estimated from fetal crown-rump measurements (Morrison et ale 1959). A median collection date was not used as fetuses were collected in 2, 3-day intervals 1 wk apart so fetuses were aged from the date of collection. Conceptions occurred in the 62-day interval 18 September to 18 November with 97% of the conceptions occurring in the 33-day interval 18 September to 20 October. Con~eptions peaked (59%) 23 September to 2 October (Fig. 1). In 1986, conceptions peaked (54%)·23 September to 2 October and occurred during the 35-day interval 19 September to 23 October (Fig. 1). Conception dates for elk in the San Juan Basin in southwestern Colorado in 1965 and 1966 peaked 2 October (Boyd and Ryland 1971). There was no relationship between estimated fetal age and age of cow (r = -0.075) suggesting that conception date was not influenced by age of cow. However, the ages of the 10 cows bred after 13 October during both years were 1 yearling, 3 2-year olds, and 3 >8 years old suggesting that first-time breeders or old cows can conceive later in the rut. Limited data suggest that elk on the Forbes-Trinchera Ranch and from a portion of the White River elk population are breeding at similar rates and over similar time intervals. Fetuses were collected from 37 cow elk harvested during a late-season hunt in GMU 33, which represents part of the White River elk population (Freddy 1987b)(data courtesy of G. Byrne, Biologist, Cnow). The fetal sex ratio was 20M (57%):15F, which did not differ from unity (X2 [1] = 0.7, P = 0.40). Pregnancy rates were 0% for yearlings (n = 2) and 97% for cows ~ 2 years old. Twin fetuses were not observed. Conception dates peaked (58%) 18-27 September and conceptions occurred during the 40-day interval 4 September to 12 October (Fig. 1). Male fetuses were substantially larg~r than female fetuses in body weight, crown-rump length, and hind foot length (P < 0.002, Table 6). These results contrasted with 1986 when there were no differences in measurements of male and female fetuses (p > 0.50, Freddy 1987a). Fetuses of both sexes were larger in 1987 than 1986 probably reflecting a collection date about 14 days later in 1987 (~~ 0.01, Table 6). Male fetuses were estimated to have been �7/88 49 conceived about 8 days earlier than female fetuses (P = 0.002). Eviscerated body weights of cows having male and female fetuses were not different (P > 0.30), and male fetuses came from all age classes of cows suggesting that differences in fetal size were not due to overall condition or age of cow at breeding. Fetuses collected throughout December from GMU 33, White River, were larger than fetuses from the Forbes-Trinchera, but this may primarily reflect the time of collection and not inherent differences between populations (Table 6). For the Forbes fetuses, regressions between hind foot length and crown-rump length (linear) and crown-rump length and body weight (curvilinear) were highly correlated (r2 > 0.90). Regressions may allow detecting yearly differences in fetal growth rates. Forbes Deer Nineteen adult (> 1 yr old) female mule deer were selectively shot Forbes-Trinchera-Ranch 29 March-l April 1988 to obtain reproductive indices of body condition. Reproductive tracts were obtained from and 18, >2-year-old females. Average age of these females was 5.4 years (Appendix B). on the tracts and 1 yearling + 0.8 (SE) All females> 2 years old were pregnant, but the yearling doe was not pregnant. The 34 fetuses produced fetal rates of 1.79 fawns/doe, 0 fawns/yearling doe, and 1.89 fawns/doe >2 years old. Fawns occurred as 3 singletons, 14 twins, and 1 set of triplets. The triplets occurred in a doe 8 yrs old. Fetal rates have been lowest for does aged as yearlings or >10 years and nearly constant for does aged 2-9 (Table 7). Fetal rates of Forbes-Trinchera deer have been exceeded only by fetal rates of deer in Middle Park for herds in Colorado where such data is available (Table 8). Fetal rates by age class of doe have been similar for Forbes-Trinchera and Middle Park (Table 7). Frequencies of twinning and triplets in ForbesTrinchera deer met or exceeded rates in Middle Park, the Poudre River, and the Piceance Basin. Quadruplets have been measured only in Middle Park, and triplets have not been observed in the Piceance Basin (Table 9). Fetal sex ratios in 1988 were l3M(38%):2l F overall and lM:2F for singletons, IlM:17F for twins, and lM:2F for triplets. Fetal sex ratios did not differ from unity in 1987 or 1988 (X2 [1] = 3.35 P = 0.06) but sex ratios were dif2 ferent between years (X [1] = 3.35, P = 0.06) (Table 8). Doe deer 2-4 yrs 2 old tended to produce more female fetuses in 1988 than 1987 (X [1] = 3.25, P = 0.07) while fetal sex ratios were not different between years for does 5+ years old (P > 0.54). Fetal sex ratios did not vary from unity in the Piceance, Poudre River, and Forbes-Trinchera populations when all years of data were pooled within each herd (X2 [1] = 0.0, P > 0.40) but ratios favored 2 males in 11iddle Park (X [1] = 11.3, ! = 0.001) (Table 8). The significant yearly shifts in fetal sex ratios for Forbes-Trinchera and Middle Park populations may reflect yearly differences in weather and nutrition (Gill 1972b). Conception dates were estimated from fetal crown-rump measurements (Hudson and Browman 1959) using a median collection date of 30 March 1988. Conceptions peaked (50%) between 6 and 11 December 1987 (Fig. 2). All conceptions were estimated to have occurred in the 19-day interval from 30 November-18 December. In 1986, conceptions peaked (67%) 3-8 December and occurred during the 12-day interval from 29 November-lO December (Fig. 2). There was no relationship between estimated fetal age and age of doe (r = 0.19, n = 36) suggesting that conception date was not influenced by age of doe. �so Average conception dates for Forbes-Trinchera deer were similar to estimated dates for other deer herds in Colorado (Table 10). Estimated conception intervals for Forbes-Trinchera deer were the shortest measured of any population in Colorado. This short interval cannot be attributed to high numbers of bucks available for breeding as buck:doe ratios in Middle Park and the Poudre River were also high, but breeding itervals were longer in Middle Park and the Poudre River (Table 10). There were no differences (p > 0.50) in body weight, crown-rump length, and hind foot length between male and female fetuses, although females tended to be lighter in weight (Table 11). Comparisons between male and female fetuses produced similar results in 1987 (Freddy 1987a). Fetuses were larger in 1988, probably because they were collected at a later median date of 30 March as opposed to 18 March 1987. Linear relationships occurred between crown-rump length and body weight and between hind foot length and crown-rump length (r2 > 0.93). These relationships could be used to compare fetal growth among years but only if there is a standard collection date. Mid-March is the preferred time to collect deer from the Forbes-Trinchera. Fetuses from the Forbes-Trinchera have been comparable in size to fetuses collected in Middle Park, the Poudre River, and the Piceance Basin during March of various years (Table 1). Average fetal size in the different populations was influenced by the year of collection and the days in March when collections occurred. The Forbes-Trinchera Ranch consists of 2 major areas referred to as the Blanca and Trinchera. Deer populations in these 2 large areas may function independently as observations have suggested that deer, for the most part, utilize different winter and summer ranges. Nutritional qualities of seasonal ranges are hypothesized to be different, and such differences could be reflected in sizes of fetuses. In 1988, fetuses from does collected in the Blanca were larger in weight, crown-rump length, and hind foot length (p < 0.01) and were estimated to have an earlier conception date (p = 0.003) than-fetuses from the Trinchera (Table 12). These differences were due to Trinchera female fetuses being smaller than Blanca female fetuses for all measurements (p < 0.02) as there were no differences in male fetuses between portions of the-Ranch (P > 0.10). In 1987, comparisons between areas of the Ranch were hindered by few collections from the Trinchera, but Trinchera fetuses were larger in weight, crown-rump length, and hind foot length (P < 0.05) and were estimated to have an earlier conception date (p = 0.03)(Table-12). These differences were due to Trinchera male fetuses being larger than Blanca male fetuses for all measurements (P < 0.01). This alternating in fetal size between areas may represent random noise or differences in annual production between areas of the Ranch. Further collections in forthcoming years may clarify differences in fetal size between areas of the Ranch. Body condition of adult does was variable ranging from emaciated to fair. Kistner body condition indexes averaged 35 ~ 3 (SE), which was lower than 1987 (X2 [2], P = 0.02) and placed most does in the poor condition category (Kistner et ale 1980; Table 13). Percent kidney fat (Anderson and Medin 1965a) was 16+ 2.3 (SE) for both kidneys, which was lower for both kidneys than 1987 (P < 0.04). Percent marrow fat (dry weight basis) was 92 + 0.03, which was hIgher than 1987 (p < O.OOl)(Table 13). Frequencies of marrow texture and color ratings were not different between years (X2 [2] <2.6, P > 0.26), which suggested possible problems with fat analytical procedures �51 in 1987. The generally lower indexes in 1988 compared to 1987 likely reflect the later median collection date in 1988 and not necessarily poorer nutrition in 1988. Eviscerated body weight, percents right and left kidney fat, and percent marrow fat did not differ (p> 0.08 for body weight, > 0.17 for % fat) between adult females collected in the Blanca and Trinchera portions of the Ranch in 1987 and 1988, although Trinchera does were slightly heavier and fatter both years. Body condition indexes suggest that Trinchera and Blanca females overwinter similarly while fetal size data suggest summer and fall forage may change yearly between areas of the Ranch. Body condition indexes suggest that adult female deer on the Forbes-Trinchera are performing physiologically as well or better than deer in Middle Park, the Poudre River, and Piceance Basin, Colorado (Table 13). Caution should be used when interpreting this comparative population data as collections occurred in different years and significant changes in winter conditions have been thought to affect animal performance in Middle Park and Piceance Basin (Gill 1972b, Bartmann 1986). Litter size appears related to body condition of adult females. Adult female eviscerated body weight, percent fat right kidney, and Kistner condition index increased with increasing litter size during both 1987 and 1988 (Table 14). This data is suggestive that deer reach threshold body weights to conceive multiple births and, therefore, nutritional condition prior to breeding could influence fetal rates (Julander et al. 1961). Forbes-Trinchera Hunter Harvests Elk Hunters paying a fee harvested 72 and 93 bull elk during fall 1986 and 1987, respectively. Average age of bull harvested was 4.8 + 0.1 (SE) years with no difference in average age between years (p > 0.50). Numbers of bulls harvested by age class also did not differ between years (X2 [6 ] = 1.9, P = 0.41; Fig. 3). Antler score and weight increased with age of bull with the-highest scoring and heaviest antlers coming from bulls ~8 years old (Fig. 3). Hunters having access to Forbes-Trinchera under the Ranching for Wildlife Program harvested 36 and 71 antler1ess elk during December, 1986 and 1987, respectively (includes bull calves). Average age of female elk harvested, including female calves, was 4.7 + 0.4 (SE) years with no difference in average age between years (p = 0.27). Numbers of females harvested by age 2 class also did not differ between years (X [5] 7.2, f = 0.21; Fig. 4). Eviscerated body weights of 37 adult female and 13 calf elk harvested in 1988 were 143.4 + 3.1 and 64.5 + 2.5 (SE) kgs, respectively (Fig. 4). Whole body weights for-calves were about 87 kg, assuming eviscerated body weight equaled 75% of whole body weight (Blood and Lovass 1966). Whole body weights of male and female calves from elk herds in North Park, Durango, and Creede, Colorado, in January or February, 1986, averaged 116, 105, and 91 kgs, respectively (CDOW unpubl. data), suggesting Forbes-Trinchera calves may be undersized. �52 Deer Hunters paying a fee harvested 87 and 110 bucks during fall 1986 and 1987, respectively. Average age of buck harvested for both years was 6.1 + 0.13 (SE) years, but average age differed between years (p < 0.001) with ages being 5.6 + 0.20 and 6.6 + 0.17 (SE) in 1986 and 1987, respectively. Numbers of bucks harvested by age class also differed between years (X2 [6] = 18.0, P = 0.006) primarily due to more bucks >8 years old being harvested in 1987 (Fig. 5). Antler score and weight increased with age with maximum scores and weights occurring at ages 3 and 7, respectively (Fig. 5). Hunters having access to Forbes-Trinchera under the Ranching for Wildlife Program harvested 65 and 139 antlerless deer (including buck fawns) in 1986 and 1987, respectively. Average age of female deer harvested, including female fawns, was 3.1+ 0.17 (SE) years with no difference between years (p > 0.50). Numbers of females harvested by age class also did not differ between years (X 2 [7] = 5.7, ~ = 0.58; Fig. 6). Eviscerated body weights of 108 adult female and 21 fawn deer harvested in 1988 averaged 40.8 + 0.6 and 23 + 1.1 (SE) kgs, respectively (Fig. 6). Whole body weight of fawns was about 31 kg, assuming eviscerated body weight equaled 75% of whole body weight (Anderson et ale 1974). Whole body weights of fawns collected in December in the Piceance Basin averaged 33 kg (Trobit et ale 1988) where starvation over winter has accounted for > 50% of the fawn mortality (White et ale 1987). This weight data suggests that Forbes-Trinchera fawns may be undersized and subject to low survival rates. Summary Morphological measurements of harvested deer and elk, determining age structures of harvested animals, fetal collections, and scientific collections of female deer should be continued to allow monitoring changes in the populations potentially caused by the harvest systems used on the ForbesTrinchera Ranch. Body sizes of fawns and calves harvested in December suggested these age classes may be undersized and subject to low winter survival rates. Pregnancy rates and fetal rates of both elk and deer indicated that any problems in recruitment are likely associated with survival and not production of young. Nutritional factors may be influencing both elk and deer as significant yearly shifts in fetal sex ratios have occurred although body condition of adult female deer in late winter has been satisfactory. Assigning Ages to Elk and Deer ~~ny antlered and antlerless elk and deer were assigned an age based on both dental cementum and replacement-wear techniques during 1986 and 1987. Many serious discrepancies occurred (Freddy, D. J., unpubl. rep.). There appear to be significant problems in aging male elk and deer. Ages based on dental cementum were consistently younger than those based on replacement-wear. Which technique was correct is unknown, but corroborative antler score data suggest that replacement-wear provided a more reasonable estimate for both male elk and deer. Dental cementum provided accurate estimates for known-aged antlerless elk and generally agreed with replacement-wear estimates of age for mature cows. Dental cementum did not accurately age fawn and yearling antlerless deer but generally agreed with replacement-wear estimates of age �53 for female deer >2 years old. Because of these problems, ages of animals harvested in 1986 and 1987 at Forbes-Trinchera were estimated as follows: 1) ages of male elk and deer were estimated from replacement-wear, 2) ages of antlerless elk were estimated from dental cementum, and 3) ages of antlerless deer were estimated from replacement-wear for fawns and yearlings and from dental cementum for females >2 years old. LITERATURE CITED Anderson, A. E., and D. E. Medin. 1964. Cache la Poudre deer herd, Colorado. Res. Rep. January(1):238-268. An ecological investigation of the Colo. Game, Fish, and Parks Game , and -----deer herd 1965a. Two conditions indices of the Cache la Poudre mule and their application to management. Colo. Div. Game Info. Leaflet 23. 3pp. _____ , and 1965b. An ecological investigation of the Cache la Podure deer herd, Colorado. Colo. Game, Fish, and Parks Game Res. Rep. January (1):165-195. , and -----deer herd, 1965c. An ecological investigation of the Cache la Poudre Colorado. Colo. Game, Fish, and Parks Game Res. Rep. January (4):531-552. , and -----deer herd, 1966. An ecological investigation of the Cache la Poudre Colorado. Colo. Game, Fish, and Parks Game Res. Rep. January (2):275-290. , -----mule , and D. C. Bowden. 1972. Indices of carcass fat in a Colorado deer population. J. Wildl. Manage. 36:579-594. , , and -----selected bones, 1974. Growth and morphometry of the carcass, organs, and glands of mule deer. Wildl. Monogr. 39. 122pp. Armstrong, R. A. 1950. Fetal development of northern white-tailed deer. Amer. Mid. Nat. 43:650-666. Bartmann, R. M. 1972. Piceance deer study - productivity and mortality. Colo. Div. Wildl. Game Res. Rep. July(3):345-350. 1973. Piceance deer study - productivity and mortality. Wildl. Game Res. Rep. July(2):255-261. Colo. Div. 1986. Growth rates of mule deer fetuses under different winter conditions. Great Basin Nat. 46:245-248. Blood, D. A., and A. L. Lovass. 1966. Measurements and weight relationships in Manitoba elk. J. Wildl. Manage. 30:135-140. �54 Boyd, R. J., and E. E. Ryland. 1971. estimated by fetal growth curves. Info. Leaflet 88. 2pp. Breeding dates of Colorado elk as Colo. Div. Game, Fish, and Parks Game Follis, T. B. 1972. Reproduction and hematology of the Cache elk herd. Div. Wildl. Resouces Publ. 72-8. 133pp. Utah Freddy, D. J. 1987a. Effect of elk harvest systems on elk breeding biology. Colo. Div. of Wildl. Game Res. Rep. July:lOl-120. 1987b. The White River elk herd: Div. Wildl. Tech. Bull. 37. 64pp. a perspective 1960-1985. Gill, R. B. 1969. ~liddle park deer study-productivity Game, Fish, Parks Game Res. Rep. July(1):123-l40. Colo. and mortality. Colo. 1970. Middle Park deer study - productivity and mortality. Game,Fish, Parks Game Res. Rep. July (3):337-354. Colo. 1971. Middle Park deer study - productivity and mortality. Game, Fish, Parks Game Res. Rep. July(2):189-207. Colo. 1972a. Middle Park deer study - productivity and mortality. Div. Wildl. Game Res. Rep. July(2):179-198. Colo. 1972b. Productivity studies of mule deer in Middle Park, Colorado. Proc. Second. Mule Deer Workshop. Greer, K. R., and W. W. Hawkins. 1967. Determining pregnancy in elk by rectal palpation. J. Wildl. Manage. 31:145-149. Hudson, P., and L. G. Browman. 1959. Embryonic and fetal development of the mule deer. J. Wildl. Manage. 23:295-304. Julander, D., W. L. Robinette, and D. A. Jones. 1961. Relation of summer range condition to mule deer herd productivity. J. Wildl. Manage. 25:54-60. Kistner, T. P., C. E. Trainer, and N. A. Hartmann. 1980. A field technique for evaluating physical condition of deer. Wildl. Soc. Bull. 8:11-16. Morrison, J. A., C. E. Trainer, and P. L. Wright. 1959. Breeding seasons in elk as determined from known-age embryos. J. Wildl. Manage. 23:27-34. Plotka, E. D., U. S. Seal, L. J. Verme, and J. J Dsoga. 1983. The adrenal gland in white-tailed deer: a significant source of progesterone. J. Wildl. Manage. 47:38-44. Ramsay, M. A., and R. M. F. S. SadLeI r , 1979. Detection of pregnancy in living bighorn sheep by progestin determination. J. Wildl. Manage. 43:970-973. Roper, L. A. 1972. Middle Park deer study-physical characteristics and food habits. Colo. Div. Wildl. Game Res. Rep. July(2):199-209. �55 Torbit, S. C., L. H. Carpenter, R. M. Bartmann, A. W. Alldredge, and G. C. White. Calibration of carcass fat indices in wintering mule deer. J. Wildl. Manage. (In press). Weber, B. J., M. L. Wolfe, and G. C. White. 1982. Use of serum progesterone levels to detect pregnancy in elk. J. Wildl. Manage. 46:835-837. Wesson, J. A., III, P. F. Scanlon, R. L. Kirkpatrick, and H. S. Mosby. 1977. Influence of chemical immobilization and physical restraint on steroid hormone levels in blood of white-tailed deer. Can. J. 2001. 57:768-776. White, I. R., A. J. F. Webster, I. A. Wright, and T. K. Whyte. 1985. Realtime ultrasonic scanning in the diagnosis of pregnancy and estimation of gestational age in cattle. The Vet. Record 117:5-8. White, G. C., R. A. Garrott, R. M. Bartmann, L. H. Carpenter, and A. W. Alldredge. 1987. Survival of mule deer in northwest Colorado. J. Wildl. Manage. 51:852-859. Wood, A. K., R. E. Short, A. Darling, G. L. Dusek, R. G. Sasser, and C. A. Ruder. 1986. Serum assays for detecting pregnancy in mule and white-tailed deer. J. Wildl. Manage. 50:684-687. Prepared by -:L:~.,/~.t'L.~~~~~C"";;;~f-;-~"'=;'(;-7;("-(_' David' J,. Pr eddy.>" Wildlife Researcher _ �56 Tabl e 1. Pregnancy status of CON elk on the Ny.an Elk Ranch as determined by rectal palpation, rectal ultrasound, and blood assays, 5 Decelllber 1987. Age Elk No.- (years) Pregnanc~ Status Palpation Ultrasound Bloodb RIA Seruac Progesterone ng/.l BL OR OR GR 6R YE YE 1.5 2.5-3.5 2.5 1.5 1.5 1.5 2.5 no no no no no no no no no no unknown no no no yes yes no yes yes no yes 1.08 0.67 0.12 0.99 0.80 0.26 1.23 105 YE 121 YE 138 YE 142 YE 143 YE 145 YE 153 YE 164 YE 174 YE 175 YE 177 YE 180 YE no tag 2.5-3.5 3.5-4.5 2.5-3.5 3.5 4.5 3.5 3.5 yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes unknown yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes 2.65 4.35 0.91 2.04 2.76 2.38 4.71 3.80 3.55 3.62 3.07 5. 14 3.99 4 11 37 45 50 173 200 10 r: ..J • ..J 3.5 2.5-3.5 4.5 4.5 2.5-3.5 -Elk eartag nUlber and color: BL=blue, OR=orange, 6R=green, YE=yellow bMHeifercheckM co~~ercial blood test, done 16 Harch 1988, result is Most frequent score of 4 independent observers; observers agreed 1004 except on salllpies 11 OR, 138 YE, 200 YEo cRadioi.munoassays done 18 ~arch 1988. �57 Table 2. Frequencies of correct and incorrect judg.ents of pregnancy status of elk by oblervers using Heifercheck pregnancy assay. Herd Pregnancy Status Observer Score O~server C A kno",n R F '" Wyun Forbes (Adults) Forbes (Calves> Pregnant Pregnant Non-Preg. Non-Preg. Pregnant Pregnant Non-Preg. Non-Preg. Non-Preg. Non-Pr-eg. Correct Incorrect Correct Incorrect 13 Totals Correct Incorrect Correct Incorrect Table 3. 1987. 20 20 20 22 13 14 21 25 10 27 8 1 8 8 7 2 44 44 4 4 6 5 5 5 5 4 6 10 10 10 10 10 20 3S 9 Total s 44 Correct Incorrect 10 Seru. progesterone 20 12 1 7 Totals 13 0 2 3 13 0 2 5 13 0 2 5 10 4 5 8 1 4-4 level! lIeasured in different 44 Pregnancy Status Age Class n NYllan Jan 1987 Pregnant Non-Preg. Adult Adult 21 6 3.35 0.31 0.29 0.01 1. 15 0.05 6.14 0.59 WYlllan Dec 1987 Pregnant Non-Preg. Adult Adult 13 7 3.31 0.74 0.32 0.16 0.91 0.26 5.14 1.23 Forbes Dec 1987 Pregnant Non-Preg. Non-Preg. Adult Adult Calf 35 10 3.53 0.35 1.24 0.41 0.08 0.38 0.75 0.06 O. 11 14.86 0.80 2.92 -Tille when blood collected. 44 6 groups of elk in Herdl Year- 9 23 12 8 1 RIA Serull Progeterone nglill SE ' I'Iean l'Iax "in �58 Table 4. Fetal rates and sex ratios for age classes of fe.ale elk collected on the Forbes-Trinchera Ranch in Deceaber 1986-87. Feule Age (yrs) Number Collected Feul es Fetuses 0 4 1 13 2 3-4 5-6 7-8 9-10 11-12 13-16 11 21 13 9 4 3 8 0 2 11 21 12 8 5 3 5 Fetusesl Feule Fetal Sex F:Unk ": 0.00 0.15 1.00 1.00 0.92 0: 0:0 1: Osl 4: 4:3 7:12:2 5: 7:0 5: 2: 1 1: 3: 1 2: 1:0 4: 1:0 Q.89 1.25 1.00 0.63 Table 5. Fetal sex ratios from adult female elk collected on the Forbes-Trinchera Ranch in December 1986 and 1987. Fetal Sex Unknown No. Year Fetal Sex Fellate "ale No. (% ) No. (7.) 1986 1987 17(74) 12(33) 6(26) 24 (76) 6 2 29(49) 30 (51) 8 Totals �59 Table 6. l1easure.ents of elk fetuses from the Forbes-Trinchera in 1986-87 and fro. G"U 33, 1987, White River, Colorado. Herdl Year Body Weight (g) t1ale Feule Cro"n-Ru.p length (•• ) "ale Feule Ranch Hind Foot length (u) "ale Fuale ForbesTrinchera 29 Nov-5 Dec 1986 "ean SD .in lIa)( n 27.6 13.8 12.2 58.5 17.0 20.9 7.0 11.9 29.0 6.0 90.2 16.7 63.S 115.5 17.0 86.0 9.5 72.0 94.0 5.0 20.5 4.8 13.5 28.5 17.0 19.8 2.7 16.5 23.0 5.0 118.7 54.7 66.0 242.0 12.0 60.4 33.2 12.0 135.0 24.0 141. 4 21.1 113.0 180.0 12.0 115.4 23.3 66.0 151. 0 24.0 42.3 10.9 31.0 68.0 12.0 30.3 8.8 14.0 46.0 24.0 239.2 139.0 140.0 510.0 6.0 184.8 42.0 105.0 230.0 14.0 188.3 33.7 165.0 255.0 6.0 56.6 16.3 25.0 75.0 14.0 59.8 12.3 47.0 80.0 5.0 12-14 &: 19-21 Dec 1987 tiean SD lIin lDax n GMU 33 White River 1-30 Dec 1987 Mean SD lIin fftax n 257.9 123.6 49.0 415.0 14.0 �60 Table 7. Fetal rates for age classes of adult female .ule deer Forbes-Trinchera Ranch in 1987-88 and in Middle Park 1969-72. Age of Doe (yrs) Number Does Forbes-Trinchera 1 2-3 4-5 6-7 8-9 L 10 Middle 1 2 3-7 L8 Collected Fetuses Fetuses/ Doe 1987-88 4 4 13 6 6 4 25 12 13 8 4 5 1.00 1.92 2.00 2.17 2.00 1.25 Park 1969-72 26 18 88 40 33 38 163 69 1.27 2. II 1. 85 1.72 on the �61 Tabl e 8. Pregnancy and fetal rates for Forbes-Trinchera lule deer populations in Colorado. Herd Year ForbesTrinchera 1987 1988 Totals or Ave. Middle Parka 1969 1970 1971 1972 Totals or Ave. Piceanceb Basin 1971 1972 1973 . Totals or Ave. Poudrec River 19611965 No. Deer Collected Yearl. L_2yrs No. Fetuses Fetal Rate Fetal Sex Ratio P1:F 3 1 15 18 100 0 100 100 33 34 1.83 1.79 20:13 13:21 4 33 75 100 67 1.81 33:34 2 7 11 6 39 35 40 33 79 69 81 73 1.93 1.64 1.59 1.87 43:25 47:23 43:32 29:27 26 147 302 1.75 162: 107 5 5 19 12 15 46 100 100 79 100 93 89 28 29 94 1.65 1.45 1.45 13:15 16:13 45:47 29 73 86 92 151 1.48 74:75 86 1.72 36135 --50-- a Gill 1969, 1970, 1971, 1972 Sarhann 1972, 1973 c Anderson 1966 It Percent Deer Pregnant Yearl. L_2yrs and other �62 Table 9. Frequencies lule deer populations of litter sizes for Forbes-Trinchera in Colorado. and other Frequency of Litter Size Herd Year 0 1 2 3 4 ForbesTrinchera 1987 1988 0 1 4 13 3 14 1 1 0 0 1 3 7 19 27 73 2 0 5 0 0 5 1 0 10 7 19 5 25 28 31 34 5 2 0 0 0 0 0 6 3 41 24 118 68 7 1 4 1 0 1 9 6 0 0 18 11 10 38 0 0 0 10 10 33 59 32 58 0 0 0 0 0 15 34 0 30 68 Totals Percent I'tiddleParka 1969 1970 1971 1972 Totals Percent Piceance Basin" 1971 1972 1973 Totals Percent Poudre Riverc 1961- 9 1 0 0 1965 Percent a Gill 1972 " Bart.ann 1972, 1973 c Anderson 1966 2 0 �63 Table 10. Esti.ated conception dates for the Forbes-Trinchera other .ule deer populations in Colorado. and Conception Interval (days) Breeding Buck: Doe Ratios (":100F) Herd Fetal Collect Year Average or Peak Date(s) Of Conception Range in Conception Dates ForbesTrinchera 1987 1988 6 Dec 1986 9 Dec 1987 29 Nov-tO Dec 30 Nov-18 Dec 12 2t 52 46 Middle Park- 1969 1970 1971 1972 28 Nov 1968 1 Dec 1969 28 Nov 1970 24 Nov 1971 11 16 11 11 Nov-2 Dec Nov-15 Jan Nov-15 Dec Nov-5 Dec 40 61 35 25 53 4S 45 55 Piceanceb Basin 1971 1972 1973 4 Dec 1970 24 Nov-29 Dec 14 Nov-3 Dec 12 Nov-9 Jan 36 28 Nov 1971 4 Dec 1972 59 28 19611965 25 Nov-8 Dec 11 Nov-10 Feb 92 37-49 Poudre Riverc - Sill 1972a Bart.ann 1972,1973 c Anderson 1966 b 20 �b4 Table 11. Heasure.ents of fetal size for Forbes-Trinchera aule deer populations in Colorado. Herd/ Year Body Weight (g) Hale Feule CroMn-Ru.p length (fIR!) Hale Feule and other Hind Foot length (II1II) Hale Feule ForbesTrinchera March 1987 Mean SO lIin e ax n 243.9 54.8 164.0 382.0 20.0 234.2 68.7 156.0 388.0 13.0 188.1 11.2 175.0 213.0 20.0 188.4 13.9 171. 0 215.0 13.0 66.8 5.6 60.0 81.0 20.0 67.1 7.8 56.0 82.0 13.0 436.8 138.0 226.0 704.0 13.0 422.9 98.2 242.0 6(17.0 21.0 228.B 22.1 IBB.O 269.0 13.0 231. 4 18.4 192.0 263.0 21.0 87.2 11.9 65.0 107.0 13.0 88.3 10.0 70.0 106.0 21.0 389.2 171. 4 112.0 742.0 43.0 342.8 160.8 104.0 742.0 32.0 225.1 34.8 154.0 284.0 43.0 213.5 34.6 156.0 288.0 32.0 85.1 18.0 50.0 117.0 43.0 79.5 17. 1 48.0 116.0 32.0 217.4 30.7 158.0 280.0 14.0 227.6 33.5 155.0 283.0 20.0 226.6 21.7 200.0 251.0 5.0 212.1 33.8 146.0 March 1988 Mean SO min lIIax n Middle Parka Harch 1969-72 Mean SO sin max n Piceance Basinb March 1971-73 !'lean SD min IIi)( n Poudre Riverc March 1961-65 Mean SD .in lIlax n 398.4 121. 3 289.0 589.0 5.0 389.0 154.2 98.0 S74.0 9.0 a 6i 11, R. B., unpubl i shed data b Bart.ann, R. H., unpublished data c Anderson 1964, 1965a, 1965b, 1966 247.0 7.0 84.6 10.8 75.0 98.0 5.0 84.0 18.4 43.0 102.0 9.0 �65 Table 12. Sizes of .ule deer fetuses fro. the Trinchera Ranch in 1987-88. portions of the Forbes-Trinchera CrotolnAreal Year Trinchera 1987 Stat. Fetal "eight Ru.p (I}) length .. Hind Foot ( ) Length and Blanca < •• ) Fetal Age (days) Mean SD n 287.4 87.4 8.0 195.2 15.6 8.0 71.5 9.6 105.3 4.3 B.O B.O 1988 !'lean SD n 381. 7 128.5 17.0 221.6 22.3 17.0 83.2 11.5 17.0 111.5 S.2 17.0 Blanca 1987 Mean SD n 225.0 39.5 25.0 185.9 10.0 25.0 65.4 4.3 25.0 102.6 2.5 25.0 1988 Mean 474.7 73.0 17.0 239.1 11.6 17.0 92.6 7.2 17.0 116.0 2.8 17.0 SD n �66 Table 13. Indexes of body condition for adult fe.ale .ule deer for the Forbes-Trinchera and other deer populations in Colorado. Herdl Year Whole Body wt. (kg) Evis.Body Wt. (kg) Kidney Fat (X) Ri ght left l'IarroN Fat ('X) Kistner Fat Index Forbes-Trinchera "arch 1987 Mean SD lIin III ax n 57.4 7.0 45.0 71.0 18.0 40.0 5.0 30.0 2.0 18.0 26.0 18.0 7.0 62.0 18.0 28.0 22.0 7.0 83.0 18.0 21.1 20.1 4.0 87.0 18.0 53.0 18.0 25.0 85.0 18.0 57.3 7.7 40..0 73.0 19.0 38.3 5.4 28.0 50.0 19.0 16. 1 10. 1 6.0 45.0 19.0 16.4 10.0 5.0 41.0 19.0 92.1 12.3 42.0 98.0 19.0 35.0 13.6 10.0 55.0 19.0 21.0 12.3 17.0 28.5 17.7 10.2 15.8 23.0 88.9 69.6 83.4 81.9 58.7 42.2 18.2 69.1 34.6 16.3 93.4 87.9 43.3 "arch 1988 Mean SD lBin lIay. n Middle Park" March n = 8/yr Mean-1969 l1ean-1970 "ean-1971 l1ean-1972 60.6 Piceance Basine 1982-1983 n = 6/.on Decellber February April 63.7 67.3 59.4 Poudre Riverct Winter n=25 !'lean1961-1965 40.8 ---29.4--- 90.0 • Eviscerated weight was whole "eight less internal organs and fluids . •• Roper 1972 Torbit et ala 1988 ct Anderson et al. 1972 C �67 Table 14. Li tter size in relation to body condition indexes of adult fe~ale .ule deer on the Forbes-Trinchera Ranch, 1987-88. No. Fetuses Eviscerated Bod~ tit.(kg) SE "ean Right Kidne~ Fat % SE "ean Kistner Index SE "ean Year n 1987 1988 0 1 28 1987 1988 4 3 34.5 37.3 2. 1 1.2 11 9.7 2. 1 1.9 35 26.7 4.6 8.8 2 1987 1988 13 14 40.5 38.4 1.4 1.2 27.9 17.5 4.7 3.0 56.9 37.9 4.3 3.4 3 1987 1988 1 0 1 45 50 15 15 60 17 80 40 �68 CONCEPTION DATES FOR ELK 1~86, 1~81 40 35 P E R 38 2$ 20 ~ T ~ 15 to ? J 5 • I 9/8 v v V V Iv J7l ~ VII Sl18 Sl28 1118 10/18 11121 MONTHANDDAY(Begin 5-dav intenals) .1986 n=26 fli}ISl1 n=31 1'1 un U/17 CONCEPTION DATES FOR ELK, GHU 33, 1987 50r------------------------------------, 45 4. P 35 R 38 F 25 20 ~ 15 E 10 5 o 9/8 9/t8 9128 1011 10118 18/28 MONTHANDDAY(Begin 5-d~\I intena1s) .1987 n=36 lin 11117 Fig. 1. Estimated conception dates for elk on the Forbes-Trinchera Ranch in 1986 and 1987 (TOP) and in GMU ..,....,. ..;,..;> , White River, Colorado, 1987 (BOTTOM). �69 CONCEPTION DRTES FOR DEER 1986. 1987 40r-------------~~--------------------~ 35 P E R E N T 25 20 15 10 5 I Nov 27 Nov 30 Dec 3 Dec 5 Dec S Dec 12 Dec 15 Dec II MONTHANDDAY(Begin 3-d." intenals) glS15 n=11 E'lJ1S11 n=11 Fig. 2. Estimated conception dates for mule deer on the Forbes-Trinchera Ranch in 1986 and 1987. �70 AGES OF BULLS HARVESTED 1986, 1987 n=165 ~ E Q U E N C Y 50 45 40 35 30 25 28 IS 10 5 0 0 2 I 3 4 , 5 7 8 9 BULL AGE <YEARS) GROSS ANTLER SCORES 1987, n=85 BULLS 350 A 300 T l E R 250 S C 0 R E 150 N 200 lOa 50 0 0 1 2 3 4 5 6 7 8-9 7 1-9 BULL ACE (YEARS) • AVE. / CLASS WEIGHTS OF BULL ANTLERS 1987, n=85 20 W iC H T 18 16 14 12 10 8 l B S s 4 2 0 0 1 2 3 4 5 6 BULL AGE (YEARS) _AVE. / CLASS Fig. 3. Ages (TOP), gross Boone and Crockett antler scores (MIDDLE), and weights of antlers (BOTTOM) from bull elk harvested on the ForbesTrinchera Ranch in 1986 and 1987. �71 AGES OF FEMALE ELK HARVESTED 1986, 1987 n-96 16 14 F R E Q 12 18 N •, Y 4 U E C 2 0 1 0 2 3 6 4 5 FEf1AlE AGE (YEARS) 7 1 !-28 WEIGHTS OF ANTLERLESS ELK HARVESTED 1987 n=50 W E I G H T K G S 160 140 120 100 80 60 40 20 0 0 1 2-3 ANTlERlESS 4-5 6-1 '-20 ACE (YEARS) Fig. 4. Ages of female elk harvested (TOP) and eviscerated body weights of antlerless elk harvested in December (BOTTOM) on the Forbes-Trinchera Ranch in 1986 and 1987. �72 RGES OF BUCKS HRRVESTED 1986, 1987, n=87, 109 F R E Q U E N C Y 1 2 3 4 5 , 7 8 !-18 BUCK ACE (YEARS) .1986 mas81 GROSS ANTLER SCORES 1987, n=102 BUCKS A N T L E R S C o R E 180...-----160 140 120 100 80 60 40 20 e..L...-,-~- o 345 BUCK AGE (YEARS) IIAVE.! CLASS WEIGHTS OF BUCK ANTLERS 1987, n=102 w i H T 7~--------------6 5 4 3 hS 2 I O..L...-,---..- o 1 345 BUCK AGE (YEARS) • AVE. / CLASS Fig. 5. Ages (TOP), gross Boone and Crockett antler scores (MIDDLE), and weights of antlers (BOTTOM) from buck mule deer harvested on the ForbesTrinchera Ranch in 1986 and 1987. �73 RGES OF FEMRLE DEER HRRVESTED 1986, 1981, 0=188 40 35 F 30 E II U 25 20 N 15 Y 10 R E C 5 0 0 1 2 3 4 FEMALE AGE (YEARS) 5 6 1-1' WEIGHTS OF RNTLERLESS DEER HRRVESTED 1981, n=129 Fig. 6. Ages of female mule deer harvested (TOP) and eviscerated .body weights of antlerless deer harvested (BOTTOM) on the Forbes-Trinchera Ranch in December 1986 and 1987. �74 Appendix A. Reproductive leasureaents frol felale elk collected and 19-21 Decelber 1987 on the Forbes-Trinchera Ranch. Elk ID No. ElkAge 30087 30187 30387 30887 31287 31487 31587 31887 31987 32087 32187 32287 32387 32487 32687 32787 32887 32987 33087 33287 33587 33987 34087 34187 34287 34387 34687 34787 34887 37887 37987 38087 38187 38587 42087 42287 46187 33387 a 3 2 4 9 3 3 3 3 3 2 13 4 4 3 6 2 4 3 8 6 3 3 2 6 5 6 8 5 2 10 5 7 6 6 3 16 9 Sex F F F F F F F " F F 11 F'" " I't 11 -M F F 11 Body Weight Fetal "easure.ents" CrownHind (g) RUlp (•• ) Foot (l1li) 12-14 Hind Leg (II) Agee Days 26 52 135 58 50 67 38 75 67 21 93 111 34 85 66 144 161 59 62 242 124 91 110 151 118 110 127 100 123 127 84 133 139 107 131 113 161 162 114 122 180 145 20 30 46 30 28 34 26 34 32 19 39 41 24 37 31 49 50 31 32 68 42 29 45 69 49 43 50 43 52 51 32 61 66 40 58 50 78 77 52 54 95 68 69 75 86 77 75 80 72 79 80 67 82 83 74 81 78 89 89 76 79 93 84 99 69 77 13 98 182 104 33 72 145 121 132 70 136 165 141 104 124 91 148 135 118 122 66 12 43 32 37 14 39 52 41 24 32 22 43 36 32 29 14 65 53 57 23 84 79 81 62 82 90 83 73 79 69 85 82 77 79 60 33 '" F I't F F F '" F F 'F" 26 F F F F F 114 92 62 50 12 0.5 64 81 64 41 52 37 70 60 52 48 21 3 - Age in years for fe.ales L7 years based on dental ceeentul and for felales ~1 year old based on dental celentul or replacelent and wear . •• See Ar~strong 1950 for description of leasurelents. e Age based on ,",orrison et al. 1959. �75 Appendix B. Reproductive .easure.ents froM fe.ale aule deer collected 29 Harch-l April 198B on the Forbes-Trinchera Ranch. Deer ID No. IBB 188 18B 288 2BB 38B 388 488 488 588 5BB 6B8 68B 788 788 888 988 988 1088 1188 1188 1288 1388 1388 1488 1588 1588 1688 1688 1788 1788 1888 1888 19B8 1988 • b c DeerAge 8 B 8 7 7 3 3 2 2 6 6 3 Sex 11 F F F 11 11 F H F 1'1 F F 3 M 7 7 12 2 2 10 10 10 1 2 2 8 3 3 3 3 5 5 9 9 2 2 F 11 F F 11 F F F F 11 11 F F M 11 F F 11 F F F Body Weight Fetal Heasure.entsb CrownHind (g) Ruap (•• ) Foot 240 349 406 301 291 431 404 477 432 476 491 362 361 607 704 40B 272 226 242 493 518 198 221 226 206 204 225 227 239 233 245 244 225 226 263 269 226 203 188 192 245 250 473 490 446 409 390 456 442 533 507 638 585 341 359 244 237 230 225 222 226 235 252 250 252 257 224 224 (u) Hind Leg (•• ) Agee Days 110 110 110 .107 90 83 82 105 107 90 71 65 70 93 96 97 105 114 105 94 112 110 liB 118 119 121 109 111 138 137 117 92 88 94 129 135 94 92 88 87 87 91 89 106 93 105 106 81 81 124 121 120 113 114 123 116 124 116 136 142 107 110 116 116 114 112 112 114 114 119 119 120 120 112 112 72 eo 85 79 74 87 8a 90 89 92 Age in years for does L 2 yrs based on dental ce.entu. ~ 1 yr old based on replace.ent and wear. See Armstrong 1950 for description of .easureMents. Age based on Hudson ~nd Brow_an 1959. and for dOe! 107 113 113 115 115 117 117 113 113 122 122 113 105 105 104 118 118 ��July 1988 JOB PROGRESS REPORT State of Colorado Project No. Mammals Research W-153-R-2 ------------------------ Work Plan No. 3 --~------------------ Elk Investigations Job No. 7 Period Covered: July 1, 1987 - June 30, 1988 Author: Elk Census Methodology D. J. Freddy Personnel: R. Firth, B. Thompson, G. White, R. Bartmann ABSTRACT Number of elk in a portion of GMU 18, Middle Park, Colorado, was estimated by flying line transects with a helicopter. Estimated density of elk was 14.5 + l2.4/mi2, and the projected population was 1,276 + 1,091. The minimal number of elk in the sampled area was known to be 744. The high variance about the mean estimate was caused by the small number of groups seen (33) and the large range in group size (1-83). The small number of groups seen precluded assessing the utility of line transects to estimate numbers of elk. Next year, transects will be replicated 4 times to increase the number of observed groups to 130+, which should allow for better analyses of line transect data. ��7/88-3,7 79 ELK CENSUS METHODOLOGY David J. Freddy P. N. OBJECTIVE Evaluate methods to estimate numbers of elk during winter. SEGMENT OBJECTIVES 1. Determine the distribution and group sizes of elk in a selected herd during early and late winter using concentrated aerial surveys. 2. Use computer simulation techniques to test the effectiveness of various sampling systems to estimate numbers of elk from the known distribution of elk. METHODS AND MATERIALS A portion of Game Management Unit (GMU) 18 within Middle Park, Colorado, was selected to estimate numbers of elk. The area between Highway 125 and Troublesome Creek, about 88 mi2, was surveyed with 24 line transects (Burnham et ale 1980) spaced at 3,280 ft (1,000 m) intervals. Transects were 3 to 9 mi in length and vegetation included sagebrush, aspen, aspen-mixed conifer, and heavy conifer. Line transects were flown with a Bell-Soloy helicopter on 15 and 22 January because inclement weather precluded all transects being flown in one day. Bright sunshine, minimal wind, and excellent snow background occurred on both days. Air speed was about 50 mph, flight elevation was about 200 ft above ground, and 4 hrs were needed to fly the 137 mi of transects. Two observers and the pilot searched for elk, although the primary responsibility of the observer seated in the middle of the aircraft was to navigate. Numbers of elk in each group on both the right and left sides of the aircraft were counted. Efforts to count elk on the left side were less intense than efforts to count elk on the right side of the transect. The observer seated on the right counted and estimated perpendicular distances to those groups of elk located from the transect center line to the right. The middle observer counted and estimated perpendicular distances to those elk to the left of the transect center line. Markers placed at known distances from a transect line were used by observers to practice estimating perpendicular distances prior to flying each day. Total number of elk in the sampled area was estimated using PROGRAM TRANSECT (Laake et ale 1979). Groups of elk observed to both the left and right side of the aircraft were included in analyses (G. White, pers. comm.). RESULTS AND DISCUSSION Estimated density of elk was 14.5 + 12.4/mi2 (95% CI). The projected elk population was 1,276 ~ 1,091. The-minimal number of elk in the sampled area was 744 based on a sex-and-age classification flight flown 23 January 1988. �80 The high variance about the mean estimate was caused by the small number of groups seen (33) and the range in group size (1-83)(Table 1). Average number of elk/group was 12.788. The best sighting functions were the exponential polynomial and the negative exponential (Table 2). These sighting functions also provided the best fit for distribution of deer groups on line transects in the Piceance Basin (G. White, pers. comm.). The data suggested that elk were moving off the center line of the transect prior to being detected by observers. Flying transects, estimating sighting distances to elk, and counting elk went reasonably well for this first attempt. However, the low numbers of groups seen precluded any meaningful conclusions about the utility of using line transects to estimate numbers of elk. Next year, transects will be flown in at least 4 replicates to expand the number of groups seen to 130+, which should allow for more meaningful analyses of the line transect data (G. White, pers. comm.). LITERATURE CITED Burnham, K. P., D. R. Anderson, and J. L. Laake. 1980. Estimation of density from line transect sampling of biological populations. Wildl. Mono. 72. 202pp. Laake, J. L., K. P. Burnham, and D. R. Anderson. 1979. User's manual for program transect. Utah State Univ. Press, Logan. 26pp. �81 Table 1. Groups of elk observed on 24 line transects flown 15 and 22 January, 1988, Middle Park, Colorado. Transect no. No. elk in group Perpendicular distance (yds) Transect side 7 83 12 10 175 350 0 330 right left right right 6 43 8 5 1 1 17 3 130 430 30 75 65 50 50 50 50 right right right left left right right left right 4 5 1 60 170 140 right right left 6 6 33 5 1 13 3 4 27 5 3 420 120 60 80 50 550 60 0 120 150 250 225 right right right left left left right right right right right right 13 450 left 6 52 325 325 1eft left 19 9 500 125 left right 1 2 2 2 3 4 5 5 6 6 6 6 6 6 7 8 9 9 9 8 10 11 12 13 13 14 14 14 14 15 15 15 16 17 18 19 20 20 21 22 23 24 3 �82 Table 2. Estimated densities and variances for numbers of elk groups based upon 5 mathematical models used for analyzing line transect data. Data was grouped and the initial cut-point was 55 yards. ------------------------------------------------------------------------------ Model and no. parameters Fourier Series Expo. Polynomial Expo. Power Series Neg. Exponential Half-normal 2 2 2 1 1 Density estimate Stand. error % Coef. variation 95% CI 0.8401 1. 1340 1.0690 1.0000 0.6366 0.2320 0.4264 0.8352 0.2934 0.1673 27.61 37.60 78.15 29.34 26.28 0.3601-1. 320 0.2519-2.016 -0.6593-2.797 0.3931-1.607 0.2905-0.9828 � https://cpw.cvlcollections.org/files/original/aeef9a070b35561f0bb9fe3005c6cbd4.pdf efea667834b35784aff5647fb5fd1d37 PDF Text Text Colorado Division of Wildlife Wildlife Research Report July 1988 83 JOB PROGRESS REPORT State of Colorado Project No. . Mammals W-153-R-2 ~~~~--------------- Research Work Plan No. 1A Multispecies Job No. 1 Animal and Pen Support Facilities for.Big Game Research Period Covered: July 1, 1987 - June 30, 1988 Author: Investigations P. H. Neil ABSTRACT Thus far this fiscal year, 8 pronghorn antelope fawns and 7 bighorn sheep lambs have been successfully reared and are being trained for food habits and other nutritional studies. Seasonal intake investigations with pronghorn antelope continued throughout the year as well as investigations of various stress levels in bighorn sheep. The entire east side of the Foothills Facility was rebuilt to include a new alleyway, weighing platform, and new fencing. One elk suffered rattlesnake bite during mid-June but has recovered. All animals at the facility are presently healthy with the exception of 4 bighorn lambs that are being treated for pneumonia-related problems. _" ��85 ANIMAL AND PEN SUPPORT FACILITIES FOR BIG GAME RESEARCH Paul H. Neil P. N. OBJECTIVES To provide and maintain populations of captive animals and pen facilities support Mammal and Avian Research programs. to SEGMENT OBJECTIVES 1. Maintain animal research facilities. 2. Coordinate all rearing, training, maintenance, under one support facility manager. 3. Integrate all animal and physical plant support facility manpower and monetary requirements under a single budget. 4. Maintain 11 elk, 1 Rocky Mountain goat, up to 30 pronghorn antelope, up to 30 mountain sheep, and 11 domestic cows in suitable health and responsiveness to perform required research experiments. and research activities METHODS AND MATERIALS Routine neonate rearing procedures were used to han~rear 8 pronghorn antelope .. this fiscal year. Eight bighorn sheep lambs were born at the facility and ieft on the ewes to raise. One died from pneumonia. Daily contact is made with the animals to enhance tameness and, in most cases, seems to be a satisfactory procedure for our needs. Animals are hand-reared on undiluted, canned, evaporated milk. Seven pronghorn antelope were born at the facility, two of which were stillborn. One pronghorn orphan was received at the facility, and two fawns were captured from the wild in northeastern Colorado. The entire alleyway complex on the east side of the facility was torn down and rebuilt due to aging and weather damage. Several other repair projects and maintenance -eontlnued during the year. RESULTS AND DISCUSSION Two pronghorn antelope were captured from the wild in northeastern Colorado and incorporated into the captive research herd this fiscal year. One orphan was received from eastern Colorado, and seven fawns were born at the facility from captive does. Two of the fawns born at the facility were stillborn. The eight remaining fawns are being hand-reared on canned, evaporated milk and trained for forage selection studies. Details and approaches to this study are discussed under Work Plan lA, Job 4 (Bruce Gill, Principal Investigator). �86 RESULTS AND DISCUSSION Two pronghorn antelope were captured from the wild in northeastern Colorado and incorporated into the captive research herd this fiscal year. One orphan was received from eastern Colorado and seven fawns were born at the facility from captive does. Two of the fawns born at the facility were stillborn. The eight remaining fawns are being hand-reared on canned, evaporated milk and trained for forage selection studies. Details and approaches to this study are discussed under Work Plan lA, Job 4 (Bruce Gill, Principal Investigator). Seasonal intake measurements were taken on adult pronghorn antelope. Daily intake and weekly animal weights were recorded throughout the year. Progress and results are reported under Work Plan lA, Job 4 (Bruce Gill, Principal Investigator). Research being conducted on the various levels of stress in bighorn sheep continued and has incorporated several approaches and designs. Progress of this study is explained under Work Plan 2A, Job 4 (Mike Miller and Tom Hobbs, Principal Investigators). The entire alleyway complex on the east side of the facility was torn down and rebuilt due to aging and weather damage. All animal shelters were also rebuilt and new fencing installed. In addition, a weighing platform was installed into the alleyway to simplify the weighing procedure for pronghorn antelope. Rebuilding of many of the shelters and parts of the alleyway on the west side of the facility has begun and will continue throughout the next fiscal year. All animals at the facility are presently healthy with·-the exception of four bighorn lambs, which are being treated for pneumonia-related problems. One elk suffered a rattlesnake bite during mid-June but recovered in a short period of time. The big game research herd presently consists of 11 elk, 23 bighorn sheep, 23 pronghorn antelope, 1 Rocky Mountain goat, and 11 domestic cows. Other activities at the Foothills Wildlife Research Station consisted of educational tours for wildlife personnel from various federal and state agencies, Colorado State University personnel, local Boy/Girl Scout troops, and Wildlife Commissioners. Prepare by """"I1";"':"C?..;;..,r-","~~~O.,aw.....a....;;...- ..=".";t,__]I.00::'....e-,=-'...::l£_' __ p~Nerr Wildlife Technician III ,~ �Colorado Division of Wildlife Wildlife Research Report July 1988 87 JOB PROGRESS REPORT State of Colorado Project No. W-153-R-2 ----------------------- Work Plan No. Job No. LA --~~--------------. 3 Period Covered: Author: Mammals Research Multispecies Investications Mammals Research 2 Administration July 1, 1987 - June 30, 1988 R. B. Gill Personnel: L. E. Lovett ABSTRACT All 7 objectives listed in the Segment Narrative for Mammals Research 2 for FY 1987-88 were met. ��89 MAMMALS RESEARCH 2 ADMINISTRATION R. Bruce Gill P. N. OBJECTIVE Administer research within the Mammals Research 2 Unit for the highest productivity at the lowest cost. SEGMENT OBJECTIVES 1. Require candidate research projects to go through the Division's research project selection process before they are considered for funding. 2. Require all research study plans to be peer reviewed, reviewed and approved by the Research Leader before research is initiated. 3. Require quarterly progress reports and annual progress reports of each research study. 4. Subject all research projects to periodic review according to the Division's formal administrative review process. 5. Allocate fiscal resources and track expenditures assure fiscal responsibility and accountability. 6. Maintain a manual on current standard administrative and distribute to each Wildlife Researcher. 7. Develop, implement, and maintain an effective information transfer process that assures research results are disseminated to appropriate information users in a form that maximizes the probability that the information will be used. of each research study to operating procedures RESULTS AND DISCUSSION Nine new projects were proposed for consideration in the Division's planning and resource allocation process. All would have required additional funding to initiate in FY 1988-89. None received funding, so further pl~in8 was . discontinued. These proposed studies were: a. Replication of the pronghorn-w1nter wheat damage study in the Craig area to test how general the results of the New Raymer study are. b. Develop a market demand study for pronghorn hunting which would measure demand for pronghorn hunting on private lands and estimate how much hunters would be willing to pay for that privilege. c. Study the impacts of pesticide control of Russian wheat aphid on pronghorn survival and reproduction. �90 d. Study the response of selected mountain sheep populations to controlled, nonlethal removals (for translocations) to simulate hunting removals. e. Develop a market demand study for mountain sheep hunting which would characterize demand by category of animal (any sheep, trophy rams, ewes, etc.) and estimate demand by animal category. f. Test a catch-per-unit-effort population size. g. Devise and conduct a management experiment to test the feasibility of managing urban beaver populations using nonlethal control strategies such as vasectomization, translocation, and habitat management. h. Devise and conduct a management experiment in urban wildlife habitat development and test real wildlife responses against predicted responses. i. Devise and conduct a management experiment in backyard wildlife landscaping using Division office complex properties as the sites for the experiment. Test real wildlife responses against predicted responses. j. Develop a cooperative project with Watchable Wildlife, Information and Education, and Research which would target research specifically for its commercial value as a salable video production. The idea would be to conduct research on a species of high public appeal, use the research project results as the basis for a script and for video footage, and produce a made-for-television video to be sold for profit which would then offset both production and research costs. approach to estimating mountain lion -. Objective 2. Draft Program Narratives were prepared for two research studies (MarkRecapture Estimates of Mountain Sheep Numbers and Development of River Otter Reintroduction Procedures) and processed through the peer review process. Both projects are now in the active research phase. Objective 3. Quarterly reports were received and reviewed for each Mammals Research'2 study active during FY 1987-88. Annual Reports were received and are submitted to the Federal Aid Planner in time to meet the Division's reporting obligations to the Fish and Wildlife Service. Objective 4. Every research study except the mountain lion research study was reviewed in the field at least once during FY 1987-88. �91 Objective 5. Following the Division's formal resource allocation process, final budget allocations were prepared and submitted to each Wildlife Researcher as their target spending limit for FY 1988-89. These budget allocations are prepared in standard Federal Aid Segment Narrative formats. During FY 1987-88, expenditures for each research study were monitored via the Mammals Research Section's DBASE budget tracking data base. Wildlife Researchers received quarterly statements of budget status until the beginning of the fourth quarter, whereafter they received monthly reports until the close of the fiscal year. By July 14, 1988, the FY 1987-88 resource allocation for Mammals Research 2 Project of $576,604.00 had been 99% expended. Objective 6. Each member of the Mammals Research Staff (both Mammals Research 1 and 2) have been issued a manual briefly describing Division administration standard operating procedures. These have been prepared in notebook form to facilitate continual updating. All manuals are current. Objective 7. During FY 1987-88 the Mammals 2 Research staff utilized a variety of methods to communicate information to Division users. Scientific and technical information was conveyed via publication in professional journals. Implications of scientific and technical information to Division management programs was conveyed through training schools, one-on-one contacts, advisory input to ongoing Division management programs (e.g. habitat management initiatives), regulation formulation and review, long range plan and operation plans, standard operating procedures, simulation models, and biologist cordination meetings. In addition, responsibilities of all Terres'tria1 Wildlife Research Leaders were expanded to include not only research planning and evaluation, but management planning and evaluation as well. ��Colorado Division of Wildlife Wildlife Research Report July 1988 93 JOB PROGRESS REPORT State of Colorado Project No. W-153-R-2 ----------------------No. LA --------------------- Work Plan Mammals Research Multispecies Investigations Job No. 4 Period Covered: July 1, 1987 - June 30, 1988 Author: Wild Ruminant Forage Selection Dynamics R. B. Gill and B. J. Maynard Personnel: M. W. Miller, M. A. Wild-Bowser, P. N. Lehner, and P. H. Neil ABSTRACT Birth weights, weekly weight gains, and milk intake are compared for pronghorn fawns raised in summer 1987 vs. summer lS2~, Birth weights were nearly identical for the two years. Fawns rear e.. :;': 1987 consumed slightly more milk per day but gained weight slightly less r~p~'ily than fawns reared in 1988. Rearing and training protocol is described and research agenda is outlined. ��95 WILD RUMINANT FORAGE SELECTION DYNAMICS R. B. Gill and B. J. Maynard P. N. OBJECTIVE To evaluate the role of color vision in diet selection foraging ruminant--the pronghorn. of a small, selectively SEGMENT OBJECTIVES 1. Rear and train up to six female fawns. 2. Develop procedures, technology, and sample size requirements to test the response of pronghorn diet selection to experimental manipulation of light wavelengths. METHODS Pronghorn rearing procedures were similar to those described by Neil et al. 1979. Pronghorn fawns were removed from the dam as soon after initial nursing as possible, usually within 12-18 hours to assure imprinting on the handler. Two handlers reared all fawns, and after approximately one month of age, a single handler fed all supplemental food. Hand-rearing protocol closely followed the protocol outlined by Brinkley 1987. Particularly, newborns were isolated for ~he first three weeks after removal from the dam to facilitate imprinting on the handler. A variety of food rewards was tested for use in operant conditioning training. Initially, all fawns w.ere trained to wear training masks to accustom them to headgear. The origInal experimental procedure was to have been to study nutritional quality of native forage diets while fawns were subjected to a number of experimental treatments denying them access to specific wavelengths of light. Light wavelength treatments were to be experimentally manipulated by fitting headgear with camera cutoff filters that filtered light of specific wavelengths. Training of pronghorn for this experimental approach was discontinued when my duties were expanded, and I could no longer afford to invest the required amounts of time necessary to train the animals. Prior to fawning in spring 1988, a contract was drawn between Division to assume this study. Eight new fawns were acquired. and training proceeded as follows: esu and the Fawn rearing Fawn Rearing Five female and three male pronghorn fawns were bottle-raised at the Foothills Wildlife Research Station. One male and four females were born at the station between June 9 and June 23, 1988. The remaining two males and one female were caught from the wild between June 6 and June 22, 1988. Captive-born fawns were removed from their mothers approximately 24 hours after birth, allowing time for sufficient colostrum intake. Wild fawns were caught when they were between two and seven days of age. �96 Upon arrival, fawns were weighed, vaccinated with a seven-way vaccine against Enterotoxemia and other clostridial diseases, and placed in individual isopens. Raising fawns in isolation discouraged imprinting on other fawns and encouraged imprinting on the handler. Fawns were fed canned, evaporated milk ad libitum from 24Q-ml baby bottles with standard baby bottle nipples. Holes in the nipples were enlarged for greater milk flow. Milk diets were supplemented once daily with 1 ml liquid baby vitamins without iron. Captive-born fawns also received a daily supplement of 1 ml CUS04 solution (100 mg/ml) in order to prevent copper deficiencies encountered in the previous year's captive-born and hand-reared fawns. A schedule of five feedings per day was maintained until all fawns were at least one week old. Four feedings per day were given for the next three weeks. Fawns currently are receiving three feedings pe~ day. In addition to milk, fawns have ad libitum access to alfalfa hay, calf-manna, and water. RESULTS AND DISCUSSION Fawn Rearing Fawns generally maintained good health. Problems that were encountered were successfully treated. Two captive-born fawns initially had low blood protein levels when they were removed from their dams. These two received supplemental bovine colostrum for their first six feedings, followed by a 50/50 mixture of colostrum and milk for the next two feedings, and then 75 milk/25 colostrum for one feeding. One of these two siblings also developed lameness in her right front leg as a result of an umbilical infection. She was placed on a schedule of 0.3 cc penicillin administered subcutaneously, twice dialy for one week. She has subsequently recovered. At three weeks of age, one wild-caught buck fawn developed severe diarrhea. His milk was replaced with Revive electrolyte solution containing a dissolved antibiotic (240 mg Sulfamethoxazole/Trimetoprim) administered twice daily for four consecutive days. Bismuth Subsalicylate (lO-ml doses) was administered periodically until feces began to solidify. After two-and-one-half days on Revive, the diarrhea subsided and the fawn was taken off the Revive treatment and fed evaporated milk again. Other fawns which developed occasional bouts of diarrhea improved after a few feedings, and less severe cases recovered untreated. Birth weights averaged 3.23 1987 and 2.77 1987 and 2.95 of kg kg kg captive-born fawns were similar for 1987 and 1988. Males in 1987 and 3.65 kg in 1988. Females averaged 2.88 kg in in 1988. Average overall birth weights were: 2.96 kg in in 1988 (Iable 1). Fawns gained weight more rapidly in 1988 than in 1987 (0.84 vs. 0.78 kg/wk). This occurred despite slightly greater milk intake in 1987 than in 1988 (570 vs. 564 ml/day)(Iable 2). The eight fawns reared in 1988 are to be used in an investigation of the role of pronghorn color vision in diet selection. Electroretinograms will be used �97 to measure retinal reception of varying wavelengths of light throughout the "visible" light spectrum and continuing into the near infrared light spectrum (700-750 nm). Perception of light wavelengths in this range will be tested in discrimination trials in which an animal will have to choose a correct wavelength stimulus in order to obtain a food reward. In preparation for discrimination trials, a Y-maze apparatus has been constructed in the fawn rearing pen. At each feeding the fawns are led through the maze and fed at the end of either branch. In an attempt to find a sufficiently attractive food stimulus, fawns have been offered rolled oats, raisins, strawberries, blueberries, apples, and milk-soaked Grape Nuts. Only rolled oats and raisins have been eaten by any of the fawns thus far. Licorice, marshmallows, and granola are among the food rewards still to be tested. LITERATURE CITED Brinkley, K. 1987. 14(8):225-237. Pronghorn hand-rearing protocol. Anim. Keepers' Forum Neil, P. H., T. N. Woodard, and D. L. Baker. 1979. Procedures for rearing wild ruminants in captivity. Colo. Div. Wildl. Game Info. Leaflet No. 106. 4pp. Prepared Wildlife Research Leader �98 Table 1. Mean birth weights of pronghorn fawns born at Foothills Facility. II of fawns 1987 Mean weight {kg} II of {SO} fawns 1988 Mean weight (kg) (SO) -----------------------------------------------------------------.-------------Male Female Overall mean 2 7 3.23 2.88 (0.10) (0.280) 1 4 3.65 2.77 (0) (0.436) 9 2.96 (0.482) 5 2.95 (O.546) Table 2. Mean intakes and weights of pronghorn fawns raised at Foothills Facil ity. ------------------------------------------------------------------------------1988 1987 Weight (kg) (SO) Intake (ml) (SO) Weight (kg) (SO) Intake (ml) (SO) ------------------------------------------------------------------------------Week Week Week Week Week 1 2 3 4 5 4.0 4.9 6.0 6.9 4.9 (O.61 ) (O.71) (0.76 ) (1.5) (1.8) 390 560 630 620 650 (91) (110) (90) (180) (120) 4.1 4.9 6.0 7.1 8.3 (O.59) (0.78) (0.75) (0.79) (0.86) 340 520 600 620 740 (52) (110) (74) (120) (120) ..--------------------------------------------------------------------.-~-~---,---.- �Colorado Division of Wildlife Wildlife Research Report July 1988 99 JOB PROGRESS REPORT State of Colorado Project No. Work Plan W-153-R-2 Mammals Research -----------------------No. 2A ---------------------- Mountain Sheep Investigations Job No. 4 Period Covered: July 1, 1987 - June 30, 1988 Author: Experiments to Identify and Manage Stress in Mountain Sheep S. A. Gottlieb, K. A. Trust ABSTRACT We used simple water extraction to measure fecal cortisol concentrations. Water extraction yielded about 1.3X more cortisol than ether/water extraction. Assay variation was also reduced using water extraction (cv = 4%). Extraction efficiency for the water method was about 33%. We demonstrated parallelism of radioimmunoassays (RIAs) for cortisol in plasma, urine, and feces from bighorn sheep; mean slopes of logit-transformed binding data for cortisol assays from each of these media did not differ (P > 0.05) from mean slope of a standard assay curve. Repositol adrenocorticotropic hormone elevated (P < 0.05) plasma cortisol concentrations (PCCs) in treated bighorns within 2 hrs posttreatment, and urine cortisol:creatinine ratios (UCCRs) showed similar trends 4-8 hrs after treatment. Correlation between PCC and UCCR was strongest (r2 = 0.72, P < 0.001) when corrected for lag time in urine cortisol excretion. Cortlsol:creatinine ratios from urine- stained snow (SCCR) provided repeatable (cv = 9.2%) estimates of UCCRs measured directly from voided urine (r2 = 0.87, P < 0.001), supporting use of urine cortisol measurements in monitoring wild bighorns. We were unable to cause weight loss or e£fect an increase in cortisol excretion in bighorns using a relatively severe malnutrition treatment (intake restricted to 35% of calculated metabolizable energy requirement) during summer. ��101 PLANE OF NUTRITION AND BIGHORN SHEEP POPULATION PERFORMANCE M. W. Miller N. T. Hobbs P. N. OBJECTIVE To treat bighorn sheep to control disease where necessary. SEGMENT OBJECTIVES 1. Estimate the effects of animal density and plane of nutrition on endocrine responses and immune competence in mountain sheep within + 10% of the true responses with 90% confidence. - 2. Assess the utility of urine and fecal samples to indicate environmental stress in mountain sheep populations. 3. Publish results in peer-reviewed, scientific journals. REFINING FECAL CORTISOL EXTRACTION TECHNIQUES Our previous attempts to quantify cortisol in feces of bighorns were plagued by excessive inter- and intra-assay variation with average cvs two to three times greater than those for urine or serum cortisol assays. After improving both feces preparation and radioimmunoassay (RIA) performance with little overall reduction in this variability, the extraction technique itself appeared the most likely source of error. In particular, volumes of solvent used in the original protocol seemed excessive and may have rendered the extraction procedure relatively inefficient. Because evolution of the accepted extraction protocol is unclear (and apparently undocumented), we designed two experiments to examine alternatives for recovering cortisol from feces. EXTRACTION METHODS FOR FECAL CORTISOL DETERMINATION Methods and Materials We compared three recovery methods using £our~ecal pools from a single tame bighorn (A82) before (12.1, 12.2) and after (14.1, 14.2) imposing alternateday adrenocorticotropic hormone (ACTH) administration. Each pool sample had previously been lyophilized and ground in a Wil~y mill then mixed thoroughly. Nine 0.5-gm subsamples of each pool were placed in glass test tubes. For each pool, we randomly assigned three aliquots to each of three treatments (n - 12 samples/treatment): -5.0 ml deionized water was added to 0.5 gm feces. Samples were agitated for 1.0 hr, then centrifuged at 3000 RPM for 15 mins. All supernatant (x - 2.8 ml) was collected and fro~en until submitted for RIA. �102 -Samples were treated as above with diethyl ether substituted for deionized water. Ether supernatant was dried under nitrogen and residue rehydrated at 2.0 ml PBS gel, then frozen until assayed. -0.5 gm feces was rehydrated with 5.0 ml deionized water. After adding 5.0 ml diethyl ether, samples were agitated for 1.0 hr, then frozen (-200C) for 1 hr. Ether extracts were poured into clean glass tubes, and the process was repeated with an additional 5.0 ml diethyl ether. Combined extracts from each aliquot were dried under nitrogen, and residues rehydrated in 2.0 ml PBS gel, then frozen until assayed. Cortisol concentrations were determined by RIA (extracted "bench" method, previously described). We converted results from ng/ml to ng/gDM feces; coversion factors were about 10.0 for water and 4.0 for ether and combined methods. Results and Discussion Extractions using ether alone recovered virtually no cortisol (pg quantities instead of ng), and data were not analyzed further. The other two methods produced comparable results (Table 1). Water alone consistently recovered more cortisol than the combined extraction; estimated fecal cortisol concentrations from water extracts averaged about 1.3X estimates from ether/water extracts. Variation among replicates was substantially lower for water extraction (cv - 4% for water vs. cv -18% for ether/water). Both methods showed similar trends in cortisol excretion, with fecal cortisol concentrations rising more than two-fold in response to ACTH injection (sample 14.2). The magnitude of change in fecal cortisol concentration was less than was reflected by urine cortisol:creatinine ratios (Table 1) from samples collected during the same periods. Differences in urine and fecal responses may be an artifact of sampling periods used or may indicate greater integration of plasma cortisol changes in fecal cortisol excretion. Our results suggest that simple water extraction provides repeatable but possibly biased estimates of fecal cortisol concentrations. EFFICIENCY OF FECAL CORTISOL EXTRACTION METHODS Methods and Materials Based on results of previously described protocol comparisons, we used radioisotope techniques to estimate extraction efficiencies of water and ether/water protocols for fecal cortisol determinations. Ten 0.5-gm aliquots were t... __ en from each of four lyophilized and ground fecal pools; these were randomly ~~Bigned to one of two extraction protocols (five replicates per pool X protocol). We rehydrated all aliquots with 2.0 m1 deionized water containing 20 ~l 3H-cortisol colution (about 152 CPM/~l) and uncubated them overnight at 4oC. The next day we added 3.0 ml deionized water to each aliquot. We performed respective extraction methods as described previously, except that ether/water residues were rehydrated with 3.0 ml deionized water. We placed 1.0 ml of aqueous extract from each aliquot into 10.0 ml Toluene-Triton X (TTX) scintillation liquid, agitated vials, and allowed these mixtures to extract overnight. In addition to extracted samples, we included two total count controls (20 ~ 3H-cortisol in 10.0 ml TTX) and two color quench �103 controls for the water extractions (20 ~l 3H-cortisol and 1.0 supernatant in 10.0 m1 TTX). The following day we ran 10-min extracts using a liquid scintillation counter. We calculated extraction efficiencies (%) using scintillation data corected and background. m1 fecal counts of TTX average for quenching Results and Discussion Virtually no 3H-cortisol was recovered from feces using ether/water extraction; counts from ether/water extracts did not differ from background (about 35 CPM). Counts from water extracts were slightly higher (x - 50.05 CPM). However, supernatants from water extraction contained pigmented that caused heavy color quenching (about 91.8%) in quenched controls. After correcting for quenching effects, efficiency of water extraction was about 33.25%. Estimated precision of water extract results (based on cvs from replicates) was similar to previous observations (cv - 4.8%). These data, combined with results previously described, suggest that simple water extraction is preferable to ether/water for recovering cortisol from feces. Water extraction should provide a precise, although somewhat biased, estimate of fecal cortisol concentrations in bighorns. VALIDATION OF RIA FOR MEASURING CORTISOL IN EXCRETA Two approaches are commonly used to validate RIA methods: parallelism is one indicator of assay specificity, quantitiativ~ recovery is a measure of assay sensitivity. We began by comparing average slope of standard assay curves with those of plasma, urine, and fecal cortisol assays from bighorns. A valid RIA for these experimental media should produce slopes that do not differ from slope of the standard curve (Le. the sample and standard curves are parallel). Quantitative recovery demonstrates the assay's ability to measure additions of cortisol to experimental media; these determinations are in progress. PARALLELISM OF PLASMA, URINE, AND FECAL CORTISOL RIAs IN BIGHORNS Methods and Materials We examined para1le~ism between standard curves for cortisol RIA and curves generated by diluti~g pl~sma, urine, and fecal supernatants (water extraction previously described) from bighorns. A standard curve was created using 100 ~ of stock cortisol solution (100 ng/ml) in an 8-step, 2.5-fold dilution series; four replicate series were constructed. For plasma, urine, and fecal supernatants we created similar curves using 200 ~ of samples in 5-step, 2-fold dilution series; three replicate series were constructed for each sample medium, using a different sample for each replicate. Aliquots from standard, urine, plasma, and fecal series were extracted and assayed using standard "bench" cortisol RIA procedures. In addition, unextracted fecal supernatants were assayed. �104 We plotted logit transformations of percent buffer control bound (y-axis) against natural log of sample amount assayed. Regressional analyses generated "average" standard and sample assay curves. We compared slopes of sample curves to slope of the standard curve using a small-sample t-test for parallelism. Results and Discussion Average slopes from logit-transformed cortisol assays of bighorn plasma (Sp - -0.938)(Fig. 1), urine (Bu - -0.870)(Fig. 2), and extracted (Be -0.8l7)(Fig. 3) or unextracted (Bf - -O.763)(Fig. 4) fecal supernatant did not differ (p > 0.05) from average slope of the standard curve (Bs - -0.848). Performance of urine and extracted fecal supernatant assays most closely approximated the standard curve. These data support use of any of these assays in determining cortisol concentrations, and allow comparison of results derived from these methods. Some confoundment still exists in interpreting results from fecal cortisol assays. Cortisol concentrations from unextracted aqueous supernatant are about 2.5 times greater than from extracts of aqueous samples; moreover, cvs for unextracted assays are invariably smaller. We suspect that water-soluble cortisol metabolites are being detected in the unextracted (i.e. aqueous) assay, contrary to more restrictive antibody specificity claims for this RIA. Alternatively, cortisol may have greater solubility in aqueous solutions than has been previously recognized. In either case, all results to date suggest that unextracted assays of aqueous fecal supernatants recover more cortisol than extracted assays, and provide more precise estimates of fecal cortisol concentrations. CORRELATION OF CIRCULATING AND EXCRETED CORTISOL LEVELS IN BIGHORNS Methods and Materials Experiments to date have demonstrated that urine and fecal cortisol levels can be used to detect adrenal responses to exogenous ACTH and mild stressors in bighorns under laboratory conditions. However, these techniques must be adaptable to field conditions and their inherent sampling limitations if they are to be used as management tools. Here, we conducted an experiment to define temporal relationships between plasma, urine, and fecal cortisol concentrations and further ~~amine utility of urine and feces for remote sampling. Eight bighorns were randomly assigned to one of four ACTH treatments: 0 (control), 0.25, 0.50, or 1.0 U/kgj we used repositol ACTH to provide a sustained cortisol response. Sheep were housed in digestion cages (5 m2) for about 24 brs prior to injection. We collected blood, urine, and feces at 0, 2, 4, 8, 12, and 24 hrs after ACTH administration. Urine-stained fecal pellets were discarded. Blood was drawn with little or no restraint, usually in less thanl min « 2.0 mins in all cases), and we assume plasma corticoid levels to be at or near baseline in controls and at time O. We rotated bleeding order to equalize cortisol responses attributable to anticipation of bleeding, and bleeding of all animals was completed in 15-20 mins. We �105 centrifuged blood samples within 30 mins of collection and harvested plasma. Urine and feces from each collection were weighed, and urine samples were filtered. All samples were stored at -20oC between processing steps. Feces were prepared as previously described and extracted using 5.0 ml of water. We measured cortisol using RIA; urine creatinine was measured by a colorimetric method. We used analysis of variance to assess treatment effects and dose-dependence, as well as regressional analyses to examine relationships between circulating and excreted cortisol levels. For the latter, we also adjusted data to account for lag times in cortisol excretion, and again compared these to circulated levels. Results and Discussion Plasma cortisol concentrations elevated (P < 0.025) within 2 hrs after repositol ACTH treatment and remained elevated for at least 8 hrs (Fig. 5). A similar trend was seen in urine cortisol excretion, although peak response was delayed 2-6 hrs (Fig. 6). Fecal cortisol analyses are in progress. Urine cortisol:creatinine ratios (UCCR) from samples collected in the same period as plasma loosely correlated with plasma cortisol concentrations (PCC) (r2 - 0.46, P < O.Ol)(Fig. 7). We observed a better relationship (r2 0.72, P < 0.001) between UCCR and PCC by comparing PCCs with UCCRs from the succeeding sampling period (i.e. 0 hr PCCs with 2-hr UCCRs) (Fig. 8). Our results are consistent with other observations on the integrative nature of urine cortisol excretion as compared to more dynamic and instantaneous plasma cortisol levels. These data underscore the utility of urine cortisol as a potential estimator of chronic adrenal responses to environmental stressors. UTILITY OF URINE-STAINED SNOW FOR ESTIMATING URINE CORTISOL:CREATININE RATIOS Methods and Materials Urine-stained snow offers the most viable approach to field sampling of urine cortisol. To examine reliability of cortisol:creatinine ratios from snow to estimate CCRs from urine, we conducted a snow recovery experiment. We collected urine from ACTH-treated bighorns in conjunction with the previous experiment. Aliquots (about 65 ml) from each collection were warmed to about 380C in a water bath. After removing a 4-ml subsample, aliquots were poured into 17 em of fresh, lightly packed snow. In ~epositing urine into snow, we tried to si;ulate urination patterns of ~dult bighorn ewes. Urine-stained snow was coilected using empty l2-cc syringe casings pushed downward into the snow. Snow packed into the flared opening of the casing, and a relatively consistent amount was recovered with each sampling. We did not collect snow randomly from urine deposits, but instead attempted to collect from areas of heaviest deposition, as would be done in field sampling. Snow samples were thawed for 10-15 mins, mixed thoroughly, and 4-m1 sub samples retained for assay. In most cases, melting yielded 5-10 ml of liquid, but volumes ranged from about 2.5 to about 15 ml. To determine variability of this sampling method, each of 10 l80-ml aliquots were divided evenly among 5 deposit sites and sampled as described above. �106 We measured cortisol in urine and snow using an extracted RIA. Creatinine was determined by a colorimetric method using aliquots of snow diluted 1:20 and 1:5, respectively. We expressed results as cortisol:creatinine ratios (ng:mg), and compared urine and snow CCRs using regressional analyses. Results and Discussion Snow CCRs provided relatively consistent estimates of UCCRs from voided samples, although we detected a tendency for underestimation of UCCRs by SCCRs (r2 - 0.87, f < O.OOl)(Fig. 9). Our sampling procedure and cortisol assay produced minimal variability (cv - 9.2%) among replicate SCCR estimates. From these results, we conclude that urine cortisol excretion can be estimated using CCRs obtained from urine-stained snow. It follows that our techniques should be readily applied to field situations where adrenal responses of bighorns are being measured. ADRENAL RESPONSE TO CHRONIC MALNUTRITON IN BIGHORNS Methods and Materials During June-August, 1987, we attempted an experiment evaluating adrenal responses of bighorn to chronic malnutrition. We used 5 pairs of sheep and imposed treatment using a low quality ration; controls received calculated maintenance allotments of "high energy" wafers, and treatment animals were provided the same amount (by weight) of a "low energy" wafer with 70% DE of the high quality diet. We weighed bighorns weekly and collected urine and feces for 24 hrs each week immediately prior to weighing. After 2 wks of treatment, no weight loss had occurred in the treatment group. We halved the amount of low quality feed provided to treatment sheep (effectively providing -35% of calculated maintenance requirements), and continued for another week. With no weight loss measured after 1 wk of what we judged to be a severe malnutrition treatment, we decided to abandon the experiment. Results and Discussion We were unable to cause weight loss in captive bighorns using the malnutrition treatment described. Cortisol determinations on two pairs of bighorn showed no differences between control and "malnourished" bighorns; in fact, cortisol was undectable in a majority of the samples run. Failure to impose a treatment effect could be attributed to several factors. Water consumption may have increased as feed supply diminished and would account for unchanging weights; excessive urine volumes, as compared to winter collections, support this explanation. High solubility and subsequent digestibility of the low energy pellet may have reduced severity of treatment. In addition, it may be that bighorns are as efficient as their domestic counterparts in extracting energy from whatever foodstuffs are available, particularly during warmer months when energetic costs are low in nonlactating individuals. From our results, it appears difficult to nutritionally stress nonlactating bighorns during the summer, at least under our experimental conditions. This �107 leads to some question about the relative importance of malnutrition in contributing to autumn outbreaks of pneumonia in wild bighorns as compared to other unidentified factors. Table 1. Comparison of two extraction methods for estimating fecal cortisol concentrations (ng/gDM) and corresponding urine cortiso1:creatinine ratios (ng:mg). ------------------------------------------------------------------------------Water Ether/Water Urine cortiso1:creatinine (ng:mg) tv (%) x (5E) cv (%) -------------------------------------------------------------------------------- x Sample 12. 1 12.2 14.1 14.2 Prepared (5E) 11.25 (O.05 ) 12.57 (0.40) 15.58 (0.55) 36.63 (1. 07) by: 1.0 5.0 6.0 5.0 10.13 (0.92) 8.40 (1.27) 13.33 (0.67) 24.67 (2.75) ~~a~~~, ~/J~%~/~~' j~,:~,,>__ ~hael w. Mi'1ler . ~?~. 16.0 27.0 9.0 19.0 Research Associate N. Thompson Hobbs Wildlife Researcher 14.0 17.0 2.0 93.0 �108 PLASMA 4 • 3 ..J 0 -,'. ". ~"'. ~",'.-,~'" "" ....• ". -,<::::::::-. 2 ~ 0 0 1 H: 0 s => r:c -1 LL 0 1= -2 o 9 -3 -4 -2 -1 1 0 2 3 4 5 6 LOG OF uL ADDED Figure 1. Parallelism of cortisol assay for bighorn plasma. Open and closed dots represent individual observations for sample and standard curves, respectively. URINE 4 ..J 3 ~ 2 8 1 o t=> 0 r:c -1 LL o I:: -2 o 9-3 -4~ __~ __~ __~ __~ __+-__~~ -2 -1 0 1 2 3 4 __~_ 5 6 LOG OF uL ADDED Figure 2. Parallelism of cortisol assay for bighorn urine. Open and closed dots represent individual observations for sample and standard curves, respectively. �109 EXTRACTED FECES 4 o 3 ~ 2 8 1 ...J >,.:".,...,.....".. <,<, •..•••• ~........ <:::~.... •...:.•... ,: .• , ·..·········'O···::·.·.··&···-,Q .•....., -, •..~... ••.... ~ 0 :J - ..•..•.• 0···... 0..-., rc -1 - .:::::: L1. o t:: -2 (!) 9 -3 -, .,<., .... ' 0·<. . .. 0 -, ". -: -4~ __~ __~ __~ __~ __~ __~ __~ __~ -2 -1 0 1 2 3 4 5 6 LOG OF uL ADDED Figure 3. Parallelism of extracted cortisol assay for bighorn feces. Open and closed dots represent individual observations for sample and standard curves, respectively. UNEXTRACTED FECES 4 ...J 0 ~ t .... - 3 ' ..-, ,.... •. ...•.•. .... 2 8 :J "<, -, .. 6'..' 1 0 rc -1 L1. 0 t:: -2 9-3 -4 -2 -1 0 1 2 3 4 5 6 LOG OF uL ADDED Figure 4. Parallelism of unextracted cortisol assay for bighorn feces. Open and closed dots represent individual observations for sample and standard curves, respectively. �110 PLASMA 90 ~, I , I I I I ~ .•••.••• .••• .•..• \ , fr· \ Ii <, \ .\\ A.. \\ f' iQ-EI " Ii: \. It Lj Ii \ \ I} \ \\ \~ \ \ '. \ \ di 'tt \ •.._ \ -....__ -_ •.•. ". -,-,~ O~r- ,- o 10 ·tI EJ ~ 20 ~ 30 HOURS POSTIREATMENT ACTli DOSE (units/kg) e-e-e 0.00 •.•..• 0.25 •...••.•••1.00 0'0'0 0.50 Figure 5. Changes in plasma cortisol concentrations in bighorns responding to repositol ACTH administration. URINE 400 'Si .€ 9 1\ 1 \ ~300 / \\ W Z Z ell ,i\ ~200 a: o " /: I: • I I I y..... t111.i» ..J ~100 8 1 I I I I \ \ \ \ \ \ ~ ,;"', t:!., "" " "'~'" '. II I II I I. \ ".\A , \ " \.\ ~~e~ --~" ~ __.ij\ _-" ,,~ J' =~ O~r---------~--------~--------~10 20 30 o HOURS POSITREATMENT ACTli DOSE (unitsIkg) ~ ._ 0.00 0.50 .,.0-0 _ 0.25 1.00 Figure 6. Changes in urine cortisol:creatinine ratios in bighorns responding to repositol ACTH administration. Note lag time of peak responses (compare to Fig. 5). �111 o ... .. o o o ~200 § ~ 100 § CO o o (>._/.-/ -»/ ...... .r: _ r:? •• CJ·· ..... »>" ••••••• _. 0 .., , , ~.- .. »>: ••_ O.,/~······~~.,···~··o 00' ..".. 0 o o o 10 20 30 40 50 60 70 80 90 100 110 PLAMSA CORTlSOL CONCENTRATION (nglmQ Figure 7. Correlation of pees with UeeRs from samples collected during the same sampling period. (r2 - 0.46, p < 0.01). HOURS + 500 o o ..' o ._. __ ., '3-//-0 - •. ... o· o 10 20 30 40 SO 60 70 80 90 100 110 PLASMA CORTISOL CONCENTRATION Figure 8. collected 0.72, P < secretion (nglmQ Correlation of pees with UeeRs from sam~les during the succeeding sampling period (r 0.001). Correcting for lag in urine cortisol improved correlation (compare to Fig. 7). �112 400 I -300 w I.. a: U200 5 en E 8100 ~ z en 0 0 100 200 300 URINE CORTlSOL : CREATlNINE 400 SOO (nWmg) Figure 9. Correlation of CCRs estimated from urinestained snow with UCCRs from voided samples. (r2 - 0.87, P < 0.001). �Colorado Division of Wildlife Wildlife Research Report July 1988 113 JOB PROGRESS REPORT State of Colorado Project No. W-153-R-2 ------------------------ Work Plan No. __.....;;;2;;,;;A _ Mammals Research Mountain Sheep Investigations Job No. 5 Period Covered: July 1, 1987 - June 30, 1988 Author: Tests of the Mark-Recapture Method to Estimate Mountain Sheep Numbers D. F. Reed ABSTRACT Trickle Mountain located in the Southwest Region was selected as the study area. Baiting was initiated in December, 1987, and the first drop was made at the site northwest of the Dabney Ranch 7 January 1988. All yearling and adult females in this drop were allocated to the SE Region for translocation, hence no telemetry collars were placed on sheep during this occasion. The second dropnet site was then baited, and a drop was made on 1 February 1988 where 19 yearling or adult females were trapped and radio collared. Two of these were subsequently lost to possible latent capture myopathy. Thereafter sheep response to bait was tentative, and plans were made for alternative capture methods. Three helicopter flights were made combining netgun and capture gun/chemical immobilization methods. During these flights, 11 additional sheep were captured and radio collared bringing the total of radio-collared sheep to 28. Additional simulations were run, and it was decided by the coprincipal investigators and graduate research assistant that number of helicopter flights would be increased to 15 versus capturing the additional 12 animals and possibly influencing their behavior and/or distribution. ��115 TESTS OF THE MARK-RECAPTURE METHOD TO ESTIMATE MOUNTAIN SHEEP NUMBERS Dale F. Reed P. N. OBJECTIVE Test the fundamental assumptions mountain sheep numbers. of a mark-recapture procedure in estimating SEGMENT OBJECTIVES 1. Select study area. 2. Quantify the extent to which mark-recapture in mountain sheep population estimates. 3. Test the robustness data. of those assumptions model assumptions via simulations are violated with actual field ACKNOWLEDGMENTS I thank co-principal investigators R. B. Gill and G. C. White, graduate assistant A. K. Neal, J. H. Olterman, J. Cuttingham, J. H. Gould, and B. J. Poole for their continued concern and/or efforts to capture and radio collar sheep. Division personnel G. C. Wetherill, M. Cousins, E. Dumph, G. A. Hinshaw, J. Johnson, D. W. Kenvin, Jr., J. T. Rauch, R. L. Weldon; USFS personnel S. Sylva, J. Jaminet; and volunteers D. Payne, J. Colman, P. White, L. Schmidt, W. Nye, A. Nye, K. Nye, and L. Nye assisted during trapping with the dropnet. M. W. Miller did the capture gun/chemical immobiliztion work, and R. Dick piloted the Soloy helicopter. DESCRIPTION OF AREA The Trickle Mountain study area is located in south-central Colorado approximately 20 km west of Saguache. The study area includes the Trickle Mountain sheep winter range as reported by Shepherd (1975:4). Areas adjacent to this winter r%nge may be included if radio-collared sheep are located in such areas during c.he 1989 winter season wten replicate helicopter counts are planned. Most of the lands within the winter range are administered by the BLM. BLM lands are characterized by mesas topped by rolling hills and steeply dissected by drainages. Volcanic rock outcrops are associated with mesa edges as "rimrock" cliffs and ledges and with some ridge tops. Open grassy slopes are common on the mesa tops and lower slopes and hilltops. The creek bottoms are mostly narrow with flat floodplains bordered by talus slopes climbing steeply to mesa rimrocks. Surface rocks of the study area are predominantly Tertiary volcanic rocks overlying Precambrian crystalline and sedimentary rocks (Shepherd 1975). Vegetation of the winter, intermediate, and lambing ranges has been described (Shepherd 1975:20, 36, and 54, respectively). �METHODS AND MATERIALS Three methods were used to capture mountain sheep: dropnet, netgun (Coda Enterprises, Inc., 1038 E. Norwood, Mesa, AZ 85203), and capture gun using darts containing carfentanil. The dropnet used at the two Trickle Mountain sites was approximately 27 m2• These sites were baited daily to habituate the sheep to the site, vehicle, and personnel and, eventually, to the dropnet, which was typically put in place after the sheep were "hooked" on the fermented apple pulp. Once 20-30+ sheep regularly came "under the dropnet, plans were made to assemble a similar or greater number of personnel on a given day when the net would be dropped. On that day, every effort was made to keep conditions the same as before so that the sheep coming under the net would not be affected. Once the net was dropped, personnel untangled and stabilized animals in the net as soon as possible. The animals were treated for lungworm, radio collared, and released. The netgun and capture gun/chemical immobilization techniques were utilized during helicopter flights. The netgun was used only during the first helicopter flight, whereas use of both net and chemical immobilization was incorporated into the subsequent flights. First, a search was conducted with the helicopter to locate sheep, then preferably to haze a small group or individual into the open and shoot the net over one selected animal (usually at a full run). If instead of running the sheep sought cover and "held" under pinyon (Pinus edulis) - juniper (Juniperus spp.), the capture gun option was chosen; and 1-2 animals were darted from either 1) the hovering helicopter, or 2) the ground while the helicopter hovered overhead keeping the sheep in cover and "holding." In the former case, the helicopter was landed as soon as possible, and the netted animal collared and released quickly (occasionally within 3-4 mins). In the latter case, the helicopter was "backed off" and the darted animal observed until the drug had affected immobilization (usually 4-6 mins), then the helicopter was landed. The animal was then collared, given the chemical releaser, and released as mobility was regained. In addition to trapping and radio collaring sheep, 3 fixed-wing flights were conducted to check on mortality and location of the animals in relation to the study area. RESULTS AND DISCUSSION Trickle Mountain was selected as the study area. Trapping operations included capturing sheep for a transplant that had been planned by the SW Region. Baiting was in"'.;;'iated in December, 1987, and the first drop was made at the site northwest of the Dabney Ranch 7 January 1988 (Table 1). All yearl':'ngand adult females in this drop were needed for the transplant, hence no te~ewetLy collars were placed on sheep during this occasion. The second dropnet site located northeast of the Dabney Ranch was then baited, and an attempt was made on 28 January 1988 to drop the net. However, an insufficient number of sheep came under the net (some appearing tentative and leaving before others arrived), and the drop was planned for the following week on 1 February 1988. On 1 February 1988 the drop was made, and 19 yearling and adult females were trapped and radio collared (Table 1). Subsequently, two of these sheep, Black M (Channel 10, 173.237 MHz) and Black NI (Channel 11, 173.262 MHz), died. It was estimated, based on the position of the carcass in one and condition of the striated muscle tissue in the other, that these deaths resulted from capture myopathy. �117 Baiting was continued throughout February and into early March with sheep response being both tentative and sporadic. Alternative capturing methods were planned using the netgun during the first of 3 helicopter flights and either the netgun or capture gun/chemical immobilization during the second and third helicopter flights. During these flights on 17 March, 23 March, and 3 April, 4 sheep were captured with the netgun and during the flights on 23 March and 3 April, 7 sheep were captured with the capture gun, bringing the total number of radio-collared sheep to 28 (Table 1). Although sample sizes of captured animals were small, the comparison of dropnet and netgun results appear to be consistent with those reported (Koch et ale 1983). Nineteen of the 28 telemetry collars had mortality sensors (Telonics, 932 E. Impala Ave., Mesa, AZ 85204-6699) hence, the mortality status of each animal was readily determined. For the remaining 9 collars without mortality sensors, changes in location were used in estimating no deaths by the end of the segment. In addition to the 3 helicopter flights, 3 fixed-wing flights were made with SW Region Biologist Jim Olterman on 5 May, 7 June, and 22 Jun 1988. No mortality signals were received, and all but Red 5 (Channel 15, 172.637 MHz) (Table 2) had been located by the last flight (Table 3). Preliminary information on distribution was determined during these flights (Figs. 1 and 2). Movements of individual animals will be analyzed after additional data points are collected. The principal program narrative for Work Plan 2A, Job 5 was reported previously (Reed 1987:317-321). The program narrative for Work Plan 2A, Job 5 (supplement) by graduate research assistant A. K. Neal titled, "Computer simulations to statistically evaluate the mark-recapture method with mountain sheep" is included as Appendix A. LITERATURE CITED Kock, M. D., D. A. Jessup, R. K. Clark, C. E. Franti, and R. A. Weaver. 1987. Capture methods in five subspecies of free-ranging bighorn sheep: an evaluation of drop-net, drive-net, chemical immobilization and the net-gun. J. Wildl. Diseases 23:634-640. Reed, D. F. 1987. Improve matching harvest regulations with available mountain goat and sheep populations and improve methods for obtaining better popula~ion estimates. Colo. Div. of Wildl. Game Res. Rep. July Part 2:291-321. Shepherd, H. R. 1975. Vegetation of two dissimilar bighorn sheep ranges in Colorado. Colo. Div. of Wildlife, Div. Rep. No.4. 223pp. c=------t_J to Ii Prepared by Da e F. Reed Wildlife Researcher �I-' I-' 00 Table 1. Mountain sheep trapping results at Trickle Mountain during 1988. Number Capture date 7 1 17 23 Location NW NE N N Jan Feb Mar Mar 3 Apr Dabney Dabney Dabney Dabney Ranch Ranch Ranch Ranch N Dabney Ranch and N Guard Station --1 Method Dropnet Dropnet Netgun3 Netgun Capture (n-3) Netgun Capture (n-4) ~s collared for study Mortality 201 0 0 0 19 2 Unk 22 0 0 17 19 4 0 4 0 23 5 0 5 0 ------------ 28 Trapped -35 45+ 2 Transplanted Collars active (n-l)/ gun4 (n-l)/ gun ----------------------------------- Included 10 yearling and adult females. 2B1ack M (Channel 10, 173.237 MHz) and black NI (Channel 11, 173.262 MHz) deaths estimated due to latent capture myopathy. 3 Netgun was used from helicopter (n-4). 4Capture gun was used from helicopter (n-4) or from ground with helicopter hovering overhead (n-3); chemical immobilizer was carfentanil used with naloxone releaser. �119 Table 2. Number assigned to animal, collar description, channel, frequency, pulse, activation date, and status for telemetered mountain sheep in the Trickle Mountain area. ---------------------------------------------Activation Pulse per Animal Collar Frequency no. description Channel (MHz) min. (ppm) Status date I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 -- Blue white Blue orange Blue square Black A Black E Black F Black H Black J Black K Black M Black NI Black P Black R Black S Black T Black V Black ~ Black X Black Y Black Z Black NIl Black triangle Red dot Red 1 Red 2 Red 3 Red 4 Red 5 Red 6 Red 7 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 00 11 09c 10 11 12 13 14 15 16 17 172.787 172.812 172.862 172.912 172.962 173.012 173.062 173.112 173.162 173.237 173.262 172.837 172.887 172.937 172.987 173.037 173.087 173.137 173.187 173.212 173.237 172.487 172.512 172.537 172 .562 172.587 172.612 172.637 172.662 172.687 60-110b 60-110 60-110 60-110 60-110 60-110 60-110 60-110 60-110 60-110 60-110 60-110 60-110 60-110 60-110 60-110 60-110 60-110 60-110 60-110 60-110 60 60 60 60 60 60 60 60 60 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 17 3 17 23 23 23 23 '3 3 3 3 Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Mar Apr Mar Mar Mar Mar Mar Apr Apr Apr Apr 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 2A 3A 3A 4A 3A 3A 2A 3A 4A 3D 4D 6-12A 6A 4A 5A 2A 4A 4A 3A 4A 6A 2A 3A 5A 3A 2A 6A IV lA 4A aNo. - estimated age, A - active (collar transmitting), D - animal died, and U - unknown. bMortality sensors: 60 ~pm a alive, 110 ppm - dead (no movement for period of 4 hrs). Sheep 22730 ~~ not have mortality sensors. c Second series of numbers is for a second Te10nics TR 1 receiver. �120 Table 3. Flight date, aircraft type, number of mountain sheep observed, number of mountain sheep with transmitters observed, and number of transmitters located and not located during 1988. -------------------------------Number mountain .: Flight date 17 23 3 5 Mar Mar Apr May 7 Jun 22 Jun Aircraft type Soloy helicopter Soloy helicopter Soloy helicopter Cessna 185 Cessna 185 Cessna 185 Observed Observed wI transmitters 39 41 46 5 20-30 39 --------.---- sheep Transmitters located Transmitters not located 14 12 13 1 1 5 4 16 27 24 12 1 �4235~----------------------------------------~ SpanIsh Creek Rd . 4231 ~ !s 1:: J 3l·< .., ~ North ' • Pass ". 4227 ,.._,-. o i :u a. ~.•. '?-Pass Buffalo ~ Campground Ben ny ~ TrlckJe <::l 4223 Guard station -----. ~~ 421 9 I , . 358 I I I I iii 362 r 366 i r i r 370 iii '.\ Mountain A. ....._ .•. .. iiiii;;;,;__._./ 771 iii 374 i J r 378 I I Houghland t:::, , 382 I i I •.•.•••• HiD i I I 386 i I I 390 UTM east/west km . Fig. 1. Location of 16 radiocollared mountain sheep (+) the 7 June 1988 fixed-wing flight (Map by A. K. Neal). as determined from •... N •... �I-' N N 4235,.-----------------------------------------~ Spanish Creek Rd . ~ 3 ..~r .. 4231 l .. I North , ••,. Pass +- \ ,,:t;. .:lJ Q, .. ...•..•. ""'- ~ ~ ~ f Q <- 4227 Buffalo Pass ~ Campground Benny 8 ~Z(_/.' .,..'..a.. .. ~ Trickle <:) ~CKnltaln 4223 ~ + + . I ',--r--r . . 4219 358 362 i I I ..::-;-...,.. / IifJhwp' -._. ••~ •.•...._•• -..._ I I + qjl I I I I 366 I iii 370 i I 374 I I I 111 i 378 I HOlJghland ."" •• I ~Hill i 382 f iii i 386 UTM east/west km . Fig. 2. Location of 27 radiocollared mountain sheep (+) the 22 June 1988 fixed-wing flight (Map by A. K. Neal). ..4 +0+ \ ..•.. ...-\ • • + ., ... •••. • as determined from , I I 390 I �123 APPENDIX A PROGRAM NARRATIVE State: Colorado Project No.: W-125-R-2 Mammals Research Work Plan No.: _..2::..:.A.:._ Job No.: _ Mountain Sheep Investigations 5 (supplement) Computer Simulations to Statistically Evaluate the Mark-Recapture Method with Mountain Sheep A. NEED One method to estimate population numbers of mountain sheep (Ovis canadensis canadensis) is mark-resighting, based on mark-recapture (Caughley 1978) with a lincoln-Petersen estimate (Petersen 1896, lincoln 1930). This method involves first capturing and marking the animals, and subsequently recapturing or resighting them. Identifying and counting marked and unmarked individuals then provide estimates of population size. Quantitatively, the basic eitimator of population size (N) with one marking occasion and one recapture occasion is (nO (n2) (equation 1) N - where n1 - the number of animals initially caught and marked, n2 s the number of animals caught in the second occasion, and m2 - the number of marked animals caught iim the second occaston.. ',"' However, this estimator becomes more biased as sample size decreases (White et al. 1982) and may be corrected for (n1 + n2) > N by modifying equation 1 as follows (Chapman 1951, Seber 1982:60): N c (n1 + 1)(n2 + 1) ---------------(m2 +'.1) 1. (equation 2) �124 The associated estimated sampling variance is (n1 + 1){n2 + 1){n1 - m2)(n2 - m2) var (N) • ---------------------------------{m2 + 1)2 (m2 + 2) (equation 3) (Seber 1982:60). When using this method, several critical assumptions must be satisfied to accurately estimate abundance. The first assumption states that the population is closed demographically and geographically. No individual may enter through birth or immigration, or leave through death or emigration; given only one marking occasion the proportion of marked individuals must remain constant. This assumption is rarely met in a natural population, but its effects can be minimized (e.g. by shortening the time period between marking and recapturing). Some models have been developed incorporating deaths and migration (Seber 1982, Seber 1986). Kufeld et ale (1987), using radio-collars on mule deer, determined which proportion of marked animals were in the study area at any given . occasion and thus maintained a "closed" population. A second assumption of the mark-recapture method states that all animals (marked and unmarked) have an equal and constant probability of being captured and of being recaptured or resighted on subsequent occasions. Animals that are captured on a given occasion should not be more or less susceptible to being recaptured or resighted than others. In a study where animals are recaptured, if heterogeneity in capture probability occurs, the estimates can be significantly biased (Otis et ale 1978:11,25,30,34). In a study where animals were not marked but were sighted twice, Pollock and Kendall (1987) reported heterogeneity i~ sighting probability led to negative bias in the estimates. In a study where animals were live-captured and marked and then "recaptured" by resighting from the air, White and Garrott (1987:220) reported that capture heterogeneity was avoided because one method of capture and a different method of -recapture" were~ used, and that individual sighting heterogeneity did not bias estimates of population size but did underestimate the ~ariance. One explanation for this heterogeneity in probabilities may be disproportionate marking so that marks are not randomly diitributed among the animals but on2 segment of the population receives a greater proportion of marks (Rice and Harder 1977). Alternatively, the researcher may not be able to regulate heterogeneity of probabilities because trapping probabilities and reactions vary per individual animal. . 2 �125 A third assumption states that samples be random. Two possibilities exist to minimize this problem: randomize the capture effort, or randomize the recapture effort. This assumption is violated if one animal's probability of being sighted is not independent of another's (i.e. animals form more or less stable social associations). If marked animals are not randomly dispersed throughout the population and are accumulated in higher densities around the initial trapping areas, traditional variance calculations are not valid (Kufe1d et a1. 1987). The variance of the estimate increases with clumping (Rice and Harder 1977). Researchers have little control over this aspect if the animals being studied characteristically band together, but if groups tend to be randomly distributed, then groups can be counted and mean group size (number of animals per group) calculated separately to reduce the bias and still get an estimate of abundance (Bergerud and Manuel 1969, Eberhardt et a1. 1979, Seber 1986). A fourth assumption states that animals do not lose their marks. If they do, a greater proportion of unmarked individuals will be counted in the population than is actually present. A final assumption states that marked and unmarked animals be correctly identified, counted, and recorded. The observing and recording must be precise and unbiased. Violations of these assumptions result in biased estimates, and in reality, violations often occur: population demographics change; capture and sighting probabilities differ per individual; animals group together; animals lose their marks; and recording errors are made. An open population with recruitment and mortality results in an estimate that is too high (Otis et a1. 1978:10, White et a1. 1982:3). Carothers (1973) noted an underestimation of the population when probabilities of capture differ. Eberhardt (1969) reviewed several studies, noted the bias involved with unequal capture probabilities, and suggested revision of trapping methods (i.e. randomization of trap locations and shifting of traps) and modification of the Lincoln Index ~ ( i.e. N - (n1 + n2)(nl + n2 - m2) /2m2 where variables are defined as previously). In contrast, Magnusson et al. (1978) feel that violations of the equal capture probability assumption w!:l not bias the estimate if the probability of being marked and recaDtured are independent and based on beta distributlons. However this condition will only apply to populations where capture methods differ from recapture methods. In regard to sighting probabilities, Strandgaard (1967) observed that variations in behavior of individual roe deer affected the animal's likelihood of being sighted, and ·consequently the estimate was depressed. Little research has been done with regard to clumping, however Quinn (1980), using schooling populations of fish, provided a mark-recapture estimate accounting for clumping given specific marking schemes or population characteristics • ._ 3 �126 Interactions of one or more of these violations of assumptions result in an estimate that is biased, imprecise, or both. Another variable affecting the mark-recapture estimator includes the number of animals marked. For example, given a single marking session, Bartmann et ale (1987) advised that at least 45% of a mule deer population be marked to achieve a reliable estimate for small populations. In a study where roe deer were marked as they were caught, Strandgaard (1967) concluded at least 66% of the population must be marked to obtain estimates that were acceptably precise and unbiased. The number of recaptures or resightings can also affect the estimator. Improved estimates are achieved through multiple recaptures or resightings. Schnabel (1938) and Darroch (1958) described this method of mark-recapture with multiple recaptures. At each recapture, the proportion of marked animals was recorded, unmarked animals were marked, and all were then returned to the population. The proportion of marked animals over all recapture occasions was then used to estimate the population size and variance. Rice and Harder (1977) used a similar multiple recapture method with white-tailed deer but did not mark after the initial marking because resightings were done via helicopter surveys. These researchers emphasized the importance of multiple resightings to strengthen the population estimate by increasing precision. When all animals caught in a single capture occasion are marked and recaptures result from multiple resightings, separate Lincoln-Petersen estimates result from each resighting. These individual estimates must be combined to get an overall population estimate. This estimate is effected best by using a joint maximum likelihood estimate with a hypergeometric distribution, or JOMLEHD (Chapman 1951, Seber 1982:59, Seber 1986, Bartmann et ale 1987). Bartmann et ale (1987) and White and Garrott (1987:216) explained the values of this estimate over the mean or the median: minimum variance and narrower confidence interval width. Using JOMLEHD reduces bias and increases precision of the estimate (for definitions see White et ale 1982:18-19). Specifically, White and Garrott (1987) define the MLE as the value of N where the following is maximized: . k+l nl m'1 N - nl ni - mi ------------ (equation 4) N 1 • 2 n'1 and the terms are defined for all i • 2 to .k+l number of sightings. This can be found iteratively with computer. 4 �127 Aerial mark-resighting methods have been used to estimate numbers of free-ranging mountain sheep (McQuivey 1978, Leslie, Jr. and Douglas 1979, 1986). By using two different methods for capture and resighting, confounding factors (time differences, animal affinity or aversion to traps, and individual variability in these reactions) are eliminated (Otis et al. 1978:11). In comparison with fixed-wing aircraft, a helicopter also allows greater maneuverability in the air and optimum airspeed and height above the ground (Seber 1986). However, questions about the effectiveness and accuracy of helicopter mark-resighting methods exist (Furlow et al. 1981, DeYoung 1986). When using the hypergeometric model (sampling without replacement), animals, both marked and unmarked, cannot be counted more than once (Rice and Harder 1977). Visibility bias can lead to erroneous population estimates (Pollock and Kendall 1987). If the collars or marks make the animals more conspicuous to the observer, the population would be underestimated because unmarked individuals would not be noticed as readily. Alternatively, Bear et al. (1987) overestimated an elk population when marked animals were misclassified. Packard et al. (1985) noted that habitat, weather conditions, and observer experience can all lead to an underestimation of population abundance. Floyd et al. (1979) in studies of deer and Samuel et al. (1987) in studies of elk examined the effects of observer bias and evaluated the effects on counts of observers, changing ground and weather conditions,and different cover types. With moose, LeResche and Rausch (1974) noted the inaccuracy of the counts given observer experience, number of observers, snow conditions, habitat and terrain, and time of day. Finally, Caughley (1974) listed several factors that can affect the observer and the probability that an animal will be seen: thickness of cover, background, lighting, animal's color, animal's movement, animal's size, observer's eye sight, level of fatigue, speed of travel, altitude, and strip width. Because this method of mark-resighting,·with one marking period and multiple aerial resightings, is used fairly extensively, the estimator of population size should be precise and unbiased. To date, few studies have mathematically assessed the extent of problems inherent in this method. To improve estimates, this mark-resighting method needs to be evaluated quantitatively with simulations, using realistic data. With a known population size, the effectiveness of JOMLEHD estimator and its robustness to each individual asswdption need to be simulated and tested. Similarly, violations of the assumptions need to be simulated and tested with populations of known size. 5 �128 B. OBJECTIVES 1. Document the performance (precisi~n and bias) of JOMLEHD with varying capture probabilities (proportions of population marked) and varying number of sighting occasions (flights), given that all assumptions are met. HI: JOMLEHD performs acceptably despite variabilities in capture probabilities and number of resighting occasions. 2. Simulate a continuous range of heterogeneities in the sighting probabilities of individuals to evaluate the performance of the estimator. H2: JOMLEHD performs acceptably despite heterogeneous sighting probabilities of individual animals. 3. Simulate discrete probabilities· of sighting (e.g. habituation to the helicopter might cause the proportion of marked animals seen to increase or decrease sequentially per flight) to evaluate the performance of the estimator. H3: JOMLEHD performs acceptably despite changes in sighting probabilities across resighting occasions. 4. Simulate a range of aggregations among marked animals (degrees of independence of sighting probabilities) to evaluate the performance of the estimator .. H4: JOMLEHD performs acceptably despite nonrandom associations (aggregations) among individuals. .. 5. . Develop guidelines on the design and methods of captureresighting studies to improve precision and reduce the bias of the estimates. 6 �129 C. EXPECTED RESULTS OR BENEFITS Colorado requires a reliable estimator of mountain sheep numbers before intensive management systems can be devised, tested, and implemented. If mark-resighting estimates prove to be precise, unbiased, and robust to violations of model assumptions, mark-resighting estimation could be used as the standard procedure for tracking mountain sheep numbers through time. If estimates prove to be imprecise, biased, or nonrobust, suggestions will be made to improve the estimator. D. APPROACH Field Studies Several variables related to mountain sheep mark-resighti~g methods need to be determined from field studies. Reed (1987) proposes to study 28 radio-collared ewes to estimate capture probabilities, sighting probabilities across multiple resighting occasions, probability distributions for these sightings, average group size, and frequency of aggregation. Up to fifteen surveys per year will be flown to determine population estimates and to conduct these studies. This information will then be used to develop a set of realistic conditions for the simulations. Simulations The Statistical Analysis System (SAS) will be used with all MonteCarlo simulations to derive JOMLEHDs and their respective variances and confidence intervals. Four population sizes (50, 100, 200, and 500) will be used in all simulation sets. Objective 1 - Document the performance of JOMLEHD with varying capture probabilities and varying number of sig~ting occasions, given that all assumptions are met. The first objective evaluates the overall estimator performance given that all assumptions (equal and constant capture and sighting probabilities, and randomly distributed animals with no clumping) are 7 �130 met. The null hypothesis to be tested is that neither capture probabilities (proportion of population marked) nor number of sighting occasions affect the JOMLEHD. Capture probabilities are assumed uniform for the whole population and will be 0.1, 0.3, and 0.5. The number of sightings occasions (flights flown) wilf be 5, 10, 15, and 20. For this set of simulations, sighting probabilities will be 0.1, 0.3, 0.5, and 0.7 and constant. Objective 2 - Simulate a continuous range of heterogeneities in the sighting probabilities of individuals to document the performance of the estimator. The second objective consists of testing heterogeneity of sighting individuals. The null hypothesis to be tested is that heterogeneity of sighting individuals does not affect the JOMLEHD. Population sizes, capture probabilities, and number of sighting occasions used in the initial simulation will be used here. However, to simulate heterogeneity of individuals, the mean probability of sightings will tentatively be set at 0.1, 0.3, 0.5, and 0.7, and each probability of sighting will be based on a beta distribution. For each probability of sighting, three beta distributions are used (symmetrical distribution [1], skewed left distribution [2], and distribution with greater proportions in the extremes [3]). [3 ] o 0.2 0.4 0.6 0.8 SfQtrtjng Probabimty Fig. 1. Beta distributions that will-be simulated for the sighting probabilities (figure from Burnham et ale 1987) 8 1 �131 From the specified beta distribution, SAS will randomly pick a value of probability of sighting for each animal on all sj~hting occasions. This will be repeated for all animals marked with the result that each marked animal was "seen" a proportion of the total counts. All of these values will then be used to calculate an estimate of the population for that simulation, and the JOMLEHD will be calculated. Objective 3 - Simulate discrete probabilities the performance of the estimator. of sighting to document For objective '3, to detect effects on the estimator if sighting probability is variable (e.g. habituation to the helicopters), as compared to the continuous distribution, the mean sighting probability will be set at 0.5 but three discrete values (PO - 0.7, PI - 0.5, P2 0.3) for a decreasing step-wise distribution to be incorporated. The simulations will then be repeated. An increasing step-wise distribution will also be simulated to demostrate the opposite effects. The null hypothesis to be tested is that variations among flights in sighting probabilities will not affect the JOMLEHD. Objective 4 - Simulate a range of aggregations among marked animals to document the performance of the estimator. To meet the fourth objective to determine effects of aggregations of animals, average group size (mean with its variance) and fidelity to the group (percent of time together) will be incorporated into the simulations instead of a random distribution of independent animals. Sighting probability will be 0.1, 0.3, 0.5, and 0.7 with uniform distributions. The average group size and fidelity of the group will be determined from the field studies, and are expected to follow uniform rather than beta distributions.· The null hypothesis to be tested is that clumping of animals does not affect the JOMLEHD. 9 �132 In summary, the following values will be used for simulations for each objective: Objective 1.:. L a, ~ Designated population size (n) 50 100 200 500 50 100 200 500 50 100 200 500 50 100 200 500 Capture probability (c) 0.1 0.3 0.5 0.1 0.3 0.5 0.1 0.3 0.5 0.1 0.3 0.5 Number of sighting occasions (f) 5 10 15 20 5 10 15 20 5 10 15 20 5· 10 15 20 Mean sighting probabil ity (s) 0.1 0.3 0.5 0.7 0.1 0.3 0.5 0.7 0.5 0.1 0.3 0.5 0.7 Distribution of sighting probability uniform 1,2,3 Average group size (g) 1 1 1 (field data) Variance of group size (varg) 0 0 0 % of time together (%) 0 0 0 (field data) ""(field data) discrete uniform One set of simulations is composed on one value for each of t~e variables (i.e., one set for objective 1 is n=50, c=O.I, fa5, s=O.1 with constant distribution of sighting probability, g=l, varg=O, and %=0). Given the variables and their possible values, at least 624 sets are possible. For each set, one-thousand replications will be simulated. Results of the field studies will be used to determine a realistic base to indicate which values of the simulations can be expected. 10 �133 For the final analysis, for each set of simulations, the JOMLEHD will be determined, and means and variances with confidence intervals and coefficients of variation will be calculated. Also, percent relative bias (PRB), variance, and mean squared error of the bias estimate between the JOMLEHD and the true population size will be calculated. The 95% coverage of the estimator will be determined. The PRB of each method can be plotted with a given parameter to note differences between methods. Finally, goodness-of-fit tests with the estimates and the actual values will be performed. The above data will be used to check the overall performances of the estimators given different combinations of capture probabilities and numbers of sighting occasions, and violations of assumptions of constant sighting probabilities or random animal distribution. Schedule Activity Period Design study Capture and collar sheep, and conduct resighting samples Helicopter counts Conduct population estimation simulations Completion date August - December 1987 January - May 1988 November 1988 - February 1989 May 1988 - 1989 May 1989 Personnel Andrea K. Neal R. Bruce Gill Dale F. Reed Gary C. White Graduate Research Assistant Co-Principal Investigator Co-Principal Investigator Co-Principal Investigator Estimated Annual Cost ETE Requirements Expenditure CategorY Costs Contract (01) Personal Services: Contract $13,000.00 -; 11 �134 E. LOCATION The study will be located on Trickle Mountain, 3S009'N l06020'W, Saguache County, Colorado. The simulations will take place in the Fishery and Wildlife Biology Department at Colorado State University, Fort Collins, Colorado. F. RELATED FEDERAL PROJECTS This is a companion study to Colorado FA Project W-lS3-R-2 Work Plan 2A Job 5. Job 5 will provide real estimates of simulated values to define real-world ranges to be expected among simulated values. Job 5 (supplement) will simulate responses of the JOMLEHD both to preselected values and to real-world values. 12 �135 literature Cited Bartmann, R.M., G.C. White, l.H. Carpenter, _and R.A. Garrott. 1987. Aerial mark-recapture estimates of confined mule deer in pinyon-juniper woodland. J. Wildl. Manage. 51(1):41-46. - Bear, G., G.C. White, l.H. Carpenter, and R.C. Garrott. 1987. Observability bias in mark-resighting estimates of elk populations. J. Wildl. Manage. (submitted) Bergerud, A.T. and F. Manuel. 1969. Aerial census of moose in central Newfoundland. J. Wildl. Manage. 33(4):910-916. Burnham, K.P., D.R. Anderson, G.C. White, C.Brownie, and K.H. Pollock. 1987. Design and analysis methods for fish survival experiments based on release-recapture. Am. Fish. Soc. Monogr. 5. Bethesda, Maryland. 437pp. Carothers, A.D. 1973. Capture-recapture methods applied to a population with known parameters. J. Anim. Ecol. 42(1):125-146. Caughley, G. 1974. Bias in aerial survey., J. Wildl. Manage. 38(4):921-933. Caughley, G. 1978. Analysis of vertebrate populations. John Wiley and Sons. New York, New York. 234pp. Chapman, D.G. 1951. Some properties of the hypergeometric distribution with applications to zoological sample censuses. Univ. Calif. Publ. Stat. 1:131-160. Darroch, J.N. 1958. The multiple-recapture census. I. Estimation of a closed population. Biometrika 45(3/4):343-359. DeYoung, C.A. 1986. Accuracy of helicopter surveys of deer in south Texas. Wildl. Soc. Bull. 13:146-149. Eberhardt, l.l. 1969. Population estimates from recapture frequencies. J. Wildl. Manage. 33:28-39. Eberhardt, l.l., D.C. Chapman, and J.R. Gilbert. 1979. A review of marine mammal census methods. Wildl. Monogr. 63:1-46. Floyd, T.J., l.D. Mech, and M.E. Nelson. 1979. An improved method of censusing deer in deciduous-coniferous forests. J. Wildl. Manage. 4391):258-261. Furlow, R.C., M. Haderlie, and R. VandenBerge. 1981. Estimating a bighorn sheep population by mark-recapture. Desert Bighorn Council, Trans. 1981:31-33. 13 �136 Kufeld, R.C., D.C. Bowden, and D. L. Schrupp. 1987. Estimating mule deer density by combining mark-recapture and telemetry data. J. Mamm. 68(4):818-825. . LeResche, R.E. and R.A. Rausch. 1974. Accuracy and precision of aerial moose censusing. J. Wildl. Manage. 38:175-182. - Leslie, Jr., D.M. and C.L. Douglas. 1979. Desert bighorn sheep of the River Mountains, Nevada. Wildl. Monogr. 66:1-56. Leslie, Jr., D.M. and C.L. Douglas. 1986. Modeling demographics of bighorn sheep: current abilities and missing links. N. Amer. Wildl. natur. Res. Conf. Transc. 51:62-73. Lincoln, F.C. 1930. Calculating waterfowl abundances on the basis of banding returns. U.S. Dept. Agric. Circ. 118. 4pp. Magnusson, W.E., Caughley, G.J., and G.C. Grigg. 1978. A double-survey estimate of population size from incomplete counts. J. Wildl. Manage. 4291):174-176. McQuivey, R.P. 1978. The desert bighorn sheep of Nevada. Nevada Fish, Game Biol. Bull. No.6 81pp. Otis, D.L., K.P. Burnham, G.C. White, and D.R. Anderson. 1978. Statistical inference from capture data on closed animal populations. Wildl. Monogr. 62:1-135. Packard, J.M., R.C. Summers, and L.B. Barnes. 1985. Variation of visibility bias during aerial surveys of manatees. J.Wildl. Manage. 49(2):347-351. Petersen, C.G.J. 1896. The yearly immigration of young plaice into Limfjord from the German sea. Rept. Danish Biol. Stn. Pollock, K.H. and W~L. Kendall. 1987. Visibility bias in aerial surveys: a review of estimation procedures. J. Wildl. Manage. 51(2):502-510. Quinn, T.J. II. 1980. Sampling for the abundance of schooling population ,with line-transect, mark-recapture, and catch-effort methods. _ Ph.D. dissertation. University of Washington. Rice, W.R. and J.D. Harder. 1977~ Application of multiple aerial sampling to a mark-recapture census of white-tailed deer. J. Wildl. Manage. 41:197-206. Samuel, M.D., E.O. Garton, M.W. Schlegel, and R.G. Carson. 1987. Visibility bias during aerial surveys of elk in northcentral Idaho. J~ Wildl. Manage. 51(3):622-630. Schnabel, Z.E. 1938. The estimation of the total fish population of a lake. Amer. Math. Mon. 45(6):348-352. 14 �137 Seber, G.A.F. 1982. The estimation of animal abundance and related parameters (2nd edition). Macmillan Publ. Co., Inc. New York, New York. 654pp. Seber, G.A.F. 1986. A review for estimating animal abundance. Biometrics 42:267-292. Strandgaard, H. 1967. Reliability of the Petersen method tested on a roedeer population. J. Wildl. Manage. 31:643-651. White, G.C., D.R. Anderson, K.P. Burnham, and D.l. Otis. 1982. Capturerecapture and removal methods for sampling closed populations. los Alamos National laboratory. lA-8787-NREP. los Alamos, N.M. White, G.e. and R.A. Garrott. 1987. Analysis of biotelemetry data - a primer. (in prep) 15 ��Colorado Division of Wildlife Wildlife Research Report July 1988 139 JOB FINAL REPORT State of Colorado Project No. W-153-R-2 -----------------------No. 3A ---------------------- Mammals Research Work Plan Pronghorn Investigations Job No. 1 Period Covered: July 1, 1987 - June 30, 1988 Author: Pronghorn Population Dynamics Study T. M. Pojar ABSTRACT The final phase of the pronghorn census study was completed. The objective was to quantify the biases due to pronghorn movement during the quadrat search. Two helicopters were used; one with the usual crew of pilot, primary observer, and navigator/observer flew the quadrat in the standard fashion (i.e. at 15-20 m altitude and 65-100 km/hr). The other helicopter with 2 experienced observers was flown at a higher altitude (100-200 m) to broaden the visual perspective and permit the observers to track movements of pronghorns observed. The density estimate based on data from the upper crew was 4.85% less than the estimate from the lower flight. Observations from the upper helicopter indicated that 4 groups (18 animals total) were missed, and 1 group (6 animals) was erroneously included in the sample of the lower helicopter crew. These corrections resulted in a population density estimate 2.10% greater than the uncorrected estimate. Data analysis and manuscript preparation is progressing. One manuscript has been completed and submitted to The Journal of Wildlife Management.. Appendix A is a draft copy. The remainder of the project findings will initi8.l:iybe included in a single manuscript, the outline of which is Appendix B. ��141 PRONGHORN POPULATION DYNAMICS STUDY Thomas M. Pojar P. N. OBJECTIVE Develop standard operating composition inventories. procedures for pronghorn density and sex/age SEGMENT OBJECTIVES 1. Quantify the responses 2. Evaluate of pronghorns to helicopter the effects of flight responses overflights. on quadrat census bias. ACKNOWLEDGMENTS Special recognition is given to M. Bauman of the Colorado Division of Wildlife for his interest, participation, and contributions to this research effort since its inception. V. Graham, also of the CDOW, has been a consistent and valuable contributor throughout the duration of this project. D. Bowden of the Statistics Department (Colorado State University) provided statistical consultation and creative suggestions. D. Bartmann of the CDOW served as an observer during this final phase of the project, and his participation is gratefully acknowledged. PRONGHORNS' RESPONSE TO HELICOPTER QUADRAT SEARCH Justification Comparison of density estimates using random strip transects and random quadrat sampling systems has resulted in similar precision levels but a large (ca 2X) and consistent difference in estimated density (Fig. 1). The line transect method was applied to a portion of the study area for 2 consecutive years with highly inconsistent results. However, the line transect data does strongly indicate that the observability of animals decreases sharply with increasing distance from the flight-line (Fig. 2). It may be assumed, then, that the strip transect method results in an underestimation basis. The current data set does not provide any information on what biases, if any, are affecting the random quadrat density estimation. Pollock and Kendall (1987) reviewed some methods of estimating bias in aerial surveys and suggest that the best method is to have a total enumeration of a subsample of the population. Experiments censusing pastures with known numbers of mule deer (Odocoileus hemionus) resulted in an approximate underestimation bias of 33% (Bartmann et ale 1986). These experiments were conducted in pinyon (Pinus edulis)-juniper (Juniperus osteosperma) habitat type in the Piceance Basin, Colorado. Experienced observers flown over moose (Alces alces) enclosures in birch (Betula papyrifera)-spruce (Picea glauca) cover underestimated the known numbers of moose by 32% (LeResche and Rausch 1974). �142 Pronghorn (Antilocapra americana) inhabit open rolling terrain with shortgrass or sagebrush steppe vegetative types. Having evolved in this habitat type, their principal defense mechanism to disturbance is high-speed flight. The low level helicopter flights over quadrats is relatively intense and initiates the flight reaction in pronghorn. During the search of a quadrat, it is assumed that each group of animals observed either is driven from the quadrat or that it is possible for the observers to keep track of the groups (visually or by group size and composition) so they will not be counted more than once. Because of the amount of relief in the terrain, it is not possible to keep all areas of the quadrat in sight at all times. Pronghorns are notorious for their speed and endurance (Hoover et al. 1959). Sprints of 60 miles per hour are possible, and longer runs at 30 miles per hour are not uncommon (Carr 1927). It takes at least 4 mins to fly the perimeter of a quadrat, during which time a pronghorn could travel about 2 mi. This mobility, which is not encountered in other species censused with quadrats, may lead to biases in the estimates. Biases due to object mobility during quadrat censusing may be caused by one or more of the following: a. b. c. d. Group departs the quadrat before detection. Group enters the quadrat before detection. Detected group joins another group while out of sight of observers. After detection, a group may split into 2 or more groups, leading the observers to count them as new groups. It is critical to have some measure of accuracy by which to judge (and adjust, if necessary) the results of a census technique. The quadrat sampling unit lends itself to this sort of evaluation because it is a relatively small area compared to strip and line transect areas. In mule deer, pinyon-juniper habitat, it was possible to fence sample areas and stock them with known numbers of animals. This approach was considered but dismissed for pronghorns because of the expense of fencing and because fences would obviously alter the pronghorns' natural movements in response to the search aircraft. The latter is the more crucial objection since results based on experimentation that alters the pronghorns' natural flight response would not be applicable in natural situations. METHODS AND MATERIALS Approximately one-third of the Great Divide study area was desi~ted as the test area. On the study area map, it is Block 3, which is 442 mi2 in size. There are 40 randomly selected (and marked) quadrats in this area from previous years' quadrat surveys. Given certain assumptions about the variance of pronghorn density on sample quadrats, a sample of 40 quadrats was calculated to be sufficient to detect a 15% error at the 90% confidence level. The quadrat corners were marked with 2' x 3' flags of nylon reinforced, plastic tarp attached to the existing marker posts. This marking was in addition to the l' x 2' plastic panels that were in place. The intent was to make the quadrat corners visible to observers in a helicopter flying at 100200 m altitude. �143 These 40 quadrats were searched with exactly the same procedure used for the entire quadrat census during the past 4 yrs. We used a Bell-Soloy helicopter with the same observer (myself) and the same observer/navigator (Mike Bauman) as in past years. The search consisted of flying the perimeter at 65-100 km/hr, 15-20 m altitude, and transecting the interior to accomplish a thorough search. Groups of pronghorns seen on the quadrat were pursued and classified as has been done in past censuses. A second helicopter, with a pilot and 2 observers, followed the primary helicopter at an altitude of approximately 100-200 m giving a broader perspective of the primary search. There was no communication between the 2 aircraft to ensure independent observations. The observers in the upper aircraft recorded location, movement, and group sizes of all groups detected. Movement of each group was detailed throughout the search verbally on tape recorder and on a map of each quadrat. Movements of groups across quadrat boundaries and mixing and splitting of groups were recorded. RESULTS All 40 quadrats were searched in the prescribed manner on 18 August 1987. The flag markers were only partially successful in delineating the quadrat corners for the upper crew, so it was necessary for them to key on the turns of the lower helicopter to estimate the location of the actual corners. The pronghorn density estimate based on data from the upper crew was 4.85% less than the estimate from the lower flight. Observations from the upper helicopter indicated that 18 animals (4 groups of 8, 7, 1, and 2) were missed by the lower crew. It was also determined that the lower crew erroneously included 1 group of 6 animals. This group was bedded on the exterior of the quadrat and was disturbed during the perimeter flight. The lower crew was intent on watching to the interior of the quadrat and did not see the group while it was bedded. After being disturbed, the group ran onto the quadrat where the lower crew first observed them. After the above corrections were incorporated into the data set, the density estimate was increased by only 2.10%. There was no significant (p - .348) difference in the number of animals seen by quadrat between the upper and lower crews as determined by a paired t-test (t - .954, 39 df). The evidence seems strong that prongho~~ groups, upon being disturbed, do not manuever or regroup leading to their being counted more than once by the primary search team. LITERATURE CITED Bartmann, R. M., L. H. Carpenter, R. A. Garrott, and D. C. Bowden. 1986. Accuracy of helicopter counts of mule deer in Pinyon-Juniper woodland. Wildl. Soc. Bull. 14(4):356-363. . Carr, C. 1927. The speed of pronghorn antelope. J. Mammal. 8(3):249-250. �144 Hoover, R. L., C. E. Till, and S. Ogilvie. 1959. The antelope of Colorado. 1l0pp. Colo. Dept. Game and Fish. Tech Bull. No.4. LeResche, R. E., and R. A. Rausch. 1974. Accuracy and precision of aerial moose censusing. J. Wildl. Manage. 38:175-182. Pollock, K. H., and W. L. Kendall. 1987. Visibility bias in aerial surveys: A review of estimation procedures. J. Wildl. Manage. 51:502-509. Prepared bY~fZr OJif~ Wildlife Reseracher �145 GREAT DIVIDE 20 - 18 0 0 0 .•... 16 ~ w 14 le{ ~ ~ 12 C/) w l- 10 e{ a: 0 8 e{ y= ::> 0 -269.99 + 2.15x R2 6 = .991 O~ 0 5 6 7 8 TRANSECT ESTIMATE (x 1000) Figure j. 1 :,':. __ Comparison of strip vs. quadrat population size estimates. Great Divide pronghorn DAU. :r----------------------....._---------..., 1 10 CRAIG 1986 Strip Tr~In:;"gt Di:;tong" E;timot,,:; ~ o o Z £(l :;Q 10 o ~~~~~~~~--~~~~~~~~~~-ee 100 1$0 ~OO .25Q ~OO seo .oKlO 4$Q ~~~--~~~~~.---~~~ 60Xl sso £(00 65(l 700 ~, eoo Di:5tonl:le(meter:;) from f1i~ht-line Figure 2. ~umber of groups detected by estimated distance from the flight-line. Great Divide strip transects, 1986. • �146 Figure 3. Test area (Block 3) is 442 m2 and has 40 marked quadrats. �147 APPENDIX A Estimation of Proportions and Ratios from Line Transect Data Tom Drummer Assistant Professor of Mathematics Department of Mathematical Sciences Michigan Technological University Houghton, Michigan 49931 Tom Pojar Researcher, Colorado Division of Wildlife Fort Collins, Colorado 80526 Lyman L. McDonald Professor of Statistics and Zoology University of Wyoming Laramie, Wyoming 82071 �148 ABSTRACT If the population of interest in a line transect survey consists of distinct sub-populations, or classes, line transect data can be used to estimate the proportion of the population in each class, or the ratio of the number of individuals in one class to another class. However, if the various classes have unequal overall detect ability then the observed ratio or proportion is biased and should be adjusted. Procedures for examining the equal detectability hypotheses are discussed, and estimators for the desired proportions and ratios proposed and studied. The problem is further complicated when the population consists of groups of individuals, and the size of the group influences its detectability. In this case, a post stratified ratio estimator of the desired ratio is proposed. An application of this procedure to data from a pronghorn antelope survey is given, although in this illustration, the impact of the post-stratification is minimal. KEYWORDS: line transect, proportions, ratios �149 Tom Drummer Assistant Professor of Mathematics Department of Mathematical Sciences Michigan Technological University Houghton, Michigan 49931 Introduction Line transect data are traditionally used to estimate the total number of individuals in a study area. However, line transect data can also be used to estimate attributes of a population in addition to its total number. Specifically, if the population consists of several sub-populations, or classes, the estimator may desire an estimate of the proportion of the population in each class, or of the ratio of the number of items in one class to the number of items in another class. For example, if a manager is using line transect sampling to estimate the size of a game population, he or she may also need an estimate of the ratio of the number of male animals to female animals. The observed male to female ratio may be biased if, say, female animals choose habitat which makes them more likely to be detected (sampled) than males. Due to the over-representation of females in the data, the observed male to female ratio would tend to underestimate the true ratio. When using line transect data in this manner, it is important to consider the possibility that the various classes of objects may be sampled with unequal probability. Clearly, individuals at varying distance from the transect are sampled with varying probability. The concern here is that the average probabilities of detection for the various classes may differ substantially. In this instance, given sufficient data, \Ierecommend the use of the estimated sub-population sizes (densities) to estimate the desired ratios (proportions), rather than simply using the observed number of individuals in the sub-populations to obtain these estimates. In the grouped population case, it is possible that both the group's size and composition could influence its detectability. If group size alone �150 Drummer influences detectability, then, given sufficient data, we recommend estimating sub-population densities by post-stratifying on group size, and using these estimates to obtain estimates of the desired ratios (proportions). where composition influences detectability is unresolved. The case We suspect, however, that in many cases, group size and group composition are related, so adjusting for group size influence is sufficient. �151 Drummer Estimators The reader is referred to Burnham, Anderson, and Laake (1980) for a comprehensive discussion of line transect assumptions and estimation procedures. For our purposes, we assume that the population of unknown size N consists of k classes with N.~ items in the ith class (i = 1,2, •..k). The probability of detecting an individual in the ith class at perpendicular distance x from the transect is given by the detection function g.~ (x), 0< g.(x) ~ 1.0. ~ Let c. ~ =J co g.(x) dx, with 0 ~ 2Lc. i A denoting the average probability of detection for items in the ith class, = --~ n (1) where A is the size of the study area and L is the total length of transects randomly located therein. The n umb er 0f't ~ ems d e tecte d' ~n the ~.th c l'ass ~s n., w h'~ch we assume t 0 ~ have a binomial distribution with·E(n.) ~ = = N.n. (l-n.) ~~ ~ N.n. and Var(n.) ~~ ~ The n. are assumed to be independent of one another. (Seber, 1982). ~ k The total number of items detected is n = ~ ni. i=l An estimate of the number of items in the ith class is given by A -1 n.A c.~ ~ N. = n . t«, = 2L ~ ~ ~ (Seber, 1982), wit~ estimated variance given by '" Var(Ni) A A = '" () (A/2L)2 {('" ci_1)2 Var ni (Burnham and Anderson, 1976). A A Var (n.) ~ = A A (2) + ()2 ni Var ci-I)} A Under the binomial assumption, A n.(l-n.) (Quinn and Gallucci, 1980) with n.~ » I ~ (3) ('" = '" n./N. ~ ~ = '" 2L c./A. ~ �152 Drummer If the size of the study area, A, is unknown, then the population density, Di = Ni/A, is estimated. Also, Var (ni) can be estimated via " replication or, using a Poisson assumption, Var(n i)'= ni. We employ the binomial formula throughout. Let r1.) .. = N./N. denote the ratio of the number of items in class i to 1.) the number of items in class j. An·obvious estimate of rij is given by the observed ratio, r .. 1.) = n./n. . (4) 1.) If, overall, the two classes are equally detectable, then the observed ratio is approximately unbiased. Assuming that ni = nj = n, and pooling data across both classes to estimate n, an estimate of the approximate variance is given by " V~r(; ..) 1.J = (; .. 1.) 1\ + (l-n)} )2 {(l-n) n. n. 1. (5) ) If the two classes are not equally detectable, then the relative bias in r.. 1.) is approximately proportional to the ratio n. /n ., which can lead to 1. substantial bias. J Adjusting the observed ratio by estimates of ni and nj yields the adjusted estimator 1\ " r .. * 1.) 1. with estimated variance given by " " " " "2 far(N.) Var(r ..*) = (r..*) ,,~ 1.J 1\ N./N. 1.) ". (N.) 1. (6) ) ,., ,., Var (N.) } + A ~ • (7) (N .) ) The adjusted estimator is only feasible if there is sufficient uata to obtain reliable line transect population estimates for each of the classes involved. Although the adjusted estimator is approximately unbiased, its variance is large compared to the observed ratio. A simple formula expressing the relationship between the variances is not possible for the general case. study the unbiasedness for precision trade-off via a limited Monte Carlo We �153 Drummer computer Let class. simulation. Pi - N./N denote the proportion of ite~ 1. The observed p. - n./n, proportion, 1. classes have equal detectability. the bias depends in the population is approximately unbiased If this is not the case, then the extent of in the n. and the size upon the disparity Assuming equal detectability all data to obtain n, if all k 1. (N.) of each of the 1. classes. in the ith an estimate (n 1 - 1. n2 - - nk - n), and pooling of the approximate variance of p. is given 1. by Var(p.) c 1. (~.)2{(1-;) _ (1-;)} . n. n (8 ) 1. 1. The "adjusted adjusts each of the n. by n., proportion" 1. yielding 1. A A p. n. In. * k 1. l: i=l k l: where N A = N. --:-_1. __ 1._ IN ( 9) 1. n. In . 1. l. k N., Var(N) c 1. i=l l: Var (N.) 1. i=l The experimenter needs sufficient data to obtain a reliable density estimate in each of the individual et al. (1980) discuss the estimation classes. simulation variance methods of the adjusted '" * ) Var (p. 1. A - Again, the adjusted exceeds assume that N - (p. 1. proportion We note also that Burnham of total population data across classes with varying detectability. N .• line transect size when pooling The variance An estimate formula and of the approximate 1. is given by * 2 (10) ) proportion is approximately that of the observed proportion. unbiased but its variance �154· Drummer Simulation Procedure A limited computer simulation was performed in order to determine under A A what detectability conditions the "adjusted" estimators, rij* and Pi*' are A A preferrable to the "observed" estimators r .. and P., respectively. ~J .•. The simulation was limited in that we simulated line transect sampling from only two detection curves, the half-normal model (Quinn, 1977), and negative exponential model (Gates, Marshall and Olson, 1968). These curves represent the extremes in terms of shape, with the half-normal possessing a broad shoulder and the negative exponential having a sharp spike near the origin. " The shape of the curve near the origin influences Var(N). All simulation results are based on R=500 replications. For each estimator, we estimated the percent.relative bias (% BIAS), variance, coefficient of variation (CV), mean squared error (MSE), and confidence interval coverage (% COV) as detailed below. A Let 8 9 denote the parameter of interest, with from the ith replicate. 9. 1 denoting the estimate of Then: R A E(9) ::::9" A = ~ e./R i=1 1 A % BIAS :::: (9;8) x 100% ; A R " Var (9) :::: 1: i=1 cv (9) :::: I Var ~9) E A (9.-8. \ 2 -1 R x 100% ; (9) A MSE (9) For each replication, an approximate 95% confidence interval was computed as 9.~± 2 . I V~r (9.~ ) . The percent coverage is the percentage of these �155 Drummer intervals that captured the true value of e. " to the theoretical variance and also to the mean We also compared Var(9) of the variance estimates generated by the replicates. For all four estimators these quantities were in close agreement, indicating that the variance formulae provide approximately unbiased estimators of the true sampling variance. Estimation of Ratios Two populations, each of size N.~ = 1000, were randomly generated, with the parameter of interest being r12 = rij = 1.00. In other simulation runs, the ratio N1/N2 was varied, but this had no appreciable effect on the simulation results. Procedures for simulating line transect sampling are discussed by Gates (1969). A similar procedure was employed here. While each population was sampled with the same type of detection function, either half-normal or negative exponential, the parameter values of the two curves, 1, O2) were varied in order to simulate varying overall (0 probabilities of detection, with a total of 30 pairs 1, O2) examined. We chose 5 values of 01, which generated 5 different overall detection rates for population one, ranging from n1 = 0.03 to nl = 0.09. sample sizes ranging from E(n1) - 30 to E(nl) - 90. (0 This results in expected The bias in r" .. (when ~J n .) is primarily a function of the ratio n. In .. For each value of J ~ . 1 we chose 0 2 to obtain the ratios n1/n2 = 0.50; 0.60; 0.70; 0.80; 0.90; The case n1/n2 = 1.00 is the equal detectability case. 6 values of 1.00. J n._ ~ O Results In general, results for the negative exponential model paralleled those of the half-normal, so only the latter will.be examined in detail. Results �156 Drummer for the simulation are summarized in Table 1 and Figures lA-lC. The horizontal axis in the figures represents the ratio nl/n2. From Table 1 and Figures 1A and 1B, lt is clear that both % BIAS and A % COV for the observed ratio (r.. 1.) c A n./n.) are proportional to n1/n2• 1.) A The A % COV for the adjusted ratio (rij* = Ni/Nj) is consistently close to the target value of 95%, while r1.) ..* exhibits a slight positive bias that A diminishes with sample size. Perhaps most importantly, the reader should A note that the bias in the observed ratio r1.) .. does not diminish with increased sample size. A Column (6) of Table 1 A displays the ratio of Var (r..*)/Var (r..). For 1.) 1.) the equal detectability case (n1/n2 = 1.0), this ratio is in the neighborhood of 1.55. This implies that if the two classes are equally detectable and the experimenter unnecessarily uses the adjusted ratio, he will unnecessarily increase the standard error of the estimate by a factor of approximately 11.55 , or roughly 25%. Also, this ratio tends to increase sharply as n1/n2 A declines. However, MSE A (r..*) /MSE (r..) is < 1.) sample size considerations. 1.) 1. 0 for n1/n2 ~ 0.80, subject to As the disparity between detactability increases, A the bias component of MSE (r..) becomes large, while the bias component of 1.) A MSE (r..*) is consistenly close to zero. 1.) A A A .., as CV(r ..*) As expected, r 1.) ..* is relatively less precise than r1.) 1.) A exceeds CV (r..), typically by 3-8%. 1.) The disparity decreases as sample sizes increase. A Using mean squared error as the criteria, it appears that r 1.) ..* is A preferrable to rij if n1/n2 < 0.80. Of course, the experimenter does not know A A the value of n1/n2, but can obtain nl/n2 and use its value as a rough gauge. Given the potential for severe bias, and poor confidence interval coverage, A the relatively small loss in relative precision makes r1.) ..* an attractive �157 Drummer alternative if there is sufficient data available. Estimation of p, - N,/N -------~1.--1.- For this populations. study we simulated The expected line transect value sampling of the observed from three " proportion, p, - n,/n, 1. k approximate " of N,w,/ L N,w. 1. 1. • 1 J J J= value has 1. If W1 - W2 - ... - wk' then Pi is ,., approximately unbiased. When this is not the case, the bias in p. is a 1. function N . k in the Wi and of the population of the disparity We have summarized the simulation results N , N , 1 2 sizes, in terms ..., of the ratio k N.n./n-BAR, where w-BAR L - 1. 1. know any of the values them. Note k that ,.,,, statistic ] = in this n./(n/k) Of course J J ratio, such an estimate N.n. / ( L N.n./k 1. 1. . 1 J J J= this N.w,/k j=l = but given simplifies kn./n. 1. the experimenter sufficient data does not can estimate to The experimenter can use the value of 1. to judge whether or not it is advisable to use the estimator p.* - N./N or p. - n./n. 1. 1. 1. We present with expected population simulation sample two, results and found exponential comparable model The results (a , a , a ), 1 2 3 O.is to 1.50. sizes results for a situation ranging from 30 to 180. with P2 - 1000/3000 We also examined equal 1. N 1 - N in which Results - N3 - 1000, 2 We arbitrarily - 1/3, as the npopulation for situations results. where chose of interestn. the population for the half-normal sizes were not and negative were similar. presented of parameter here are from a simulation values. Only the half-normal These generated model results involving values 60 triplets, of W /W-BAR 2 are presented here. from �15~ Drummer Results We have displayed horizontal axis the most represents important maintains proportion, the targeted proportional ~ is essentially of confidence. The bias 1.0 implies that than in at least one other are less likely value = 95% at the equal interval, CV 2C, using is preferred the adjusted (p.*) > CV y! var(~.*)/var(~.) ~ ~ As previously ~ chosen in class class, than items equal case, a mean to decide over p.* ~ The squared error in P2 - n /n 2 is preferred. likely of to be detected < 1.0 implies that they one other class. A ~ rapidly elsewhere. the observed For values Although sample For the equal is N2 - N , a value 3 criteria, ~ 1.05. and The % COV for p. reaches detectability. and declines unbaised outside of this not displayed, sizes, detectability indicating a very case, ~ 1.26. stated, which • precision. a ratio in at least if .95 ~ n /n-BAR 2 proportion c 2 are more while ~ loss in relative kn./n since Nl (P.) by only 2-3% for comparable ~ small 1.0 implies detectability From Figure proportion items to be detected of n /n-BAR 2 ~ In this case, n /n-BAR> 2 items 2A-2C. ~ P.* - N./N, ~ level to n /n-BAR. 2 in Figures the ratio n /n-BAR. 2 ~ The adjusted results the experimenter estimator to use. can use the value of the statistic If kn./n ~ 1.00, then p. would ~ ~ be �159 Drummer TABLE 1 SUMMARY OF SIMULATION RESULTS FOR ESTIMATiON OF RATIOS (1) 111/112 .5 .5 .5 .5 .5 .6 .6 .6 .6 .6 .7 .7 .7 .7 .7 .8 .8 .8 .8 .8 .9 .9 .9 .9 .9 1 1 1 1 1 NOTE: -----------------------------------------------------(6) (5) (4) (7) RATIO OF VAR'S RATIO OF HSE'S 6.09 5.71 7.34 6.64 5.76 4.66 4.04 4.48 4.11 4.45 2.84 3.15 3.14 3.34 3.16 2.31 2.59 2.43 2.51 2.35 1.99 2.07 2.14 1.90 2.13 .1.55 1.46 1.59 1.61 1.49 0.32 0.19 0.18 0.12 0.09 0.53 0.35 0.23 0.19 0.17 0.77 0.60 0.41 0.39 0.31 1.50 1.05 0.79 0.68 0.56 1.88 1.58 1.49 1.47 1.45 1.57 1.46 1.60 1.61 1.50 (2) (3) EXPECTED SAMPLE SIZES n1 n2 ~ BIAS ------30 45 60 75 90 30 45 60 75 90 30 45 60 75 90 30 45 60 75 90 30 45 60 75 90 30 45 60 75 90 60 90 120 150 180 50 15 100 125 150 43 64 86 107 129 38 56 75 94 113 33 50 67 84 100 30 45 60 75 90 r" .. ~J "r ..* ~J ------------ -48.2 -49.4 -49.5 -49.8 -50.0 -38.7 -38.4 -39.7 -40.0 -39.4 -28.6 -28.5 -29.7 -29.0 -29.2 -16.4 -19.4 -19.1 -19.8 -20.2 -7.0 -9.6 -9.9 -8.4 -8.8 4.3 2.7 1.9 1.4 1.8 3.9 1.8 2.5 0.1 -0.2 3.5 3.5 0.1 0.8 1.2 0.7 2.6 0.7 2.2 1.6 5.9 2.1 1.2 0.6 0.7 5.8 1.5 1.0 2.8 2.4 6.6 2.9 3.2 1.3 2.5 r" .. ~J r" ..* ~J r" .. ~J r" ..* ~J ---------- ---------- 5.6 0.8 0.2 0.0 0.0 26.6 15.4 5.0 2.0 1.0 53.6 41.0 30.4 25.4 18.8 77 .8 68.8 66.0 56.2 50.2 88.6 88.0 86.6 85.4 84.8 93.2 93.6 94.4 95.6 96.4 21.7 17.9 15.6 13.4 12.8 22.5 19.1 15.2 13.5 13.0 24.4 19.2 16.3 14.8 13.5 25.7 19.7 16.3 15.0 14.2 25.3 19.0 16.6 16.1 13.7 28.7 21.6 18.6 15.0 14.5 COLUMN (5) IS VAR(r" ..*)/VAR(r" ..) ~J CV ~ COV .~J A ..*)/MSE(r ..) COLUMN (7) IS MSE(r"~J ~J 94.8 95.2 93.4 93.8 94.4 94.0 96.0 94.2 93.0 94.4 93.8 94.6 95.8 94.0 95.0 93.0 93.4 96.0 95.0 94.8 95.4 95.0 94.0 95.6 94.6 93.2 94.2 95.6 94.6 96.4 26.7 21.2 20.8 17.3 15.4 28.8 22.8 19.4 17.5 16.4 29.2 23.1 20.1 18.8 16.7 30.8 25.1 20.3 19.0 17.2 31.4 24.4 21.6 19.8 17.8 35.0 26.1 23.2 19.0 17.6 �160 Drummer ESTIMATION OF RATIOS FIGURE 1A - PERCENT BIAS 10 % BIAS e 'StRVED • 0 t i UTIO -30 - + -40 - A.DJUSTED RATIO i ~ ; * -10 -20 - + ~ I + * + -50 -60 0.5 0.6 0.7 O.B nl/Tr2 0.9 1 FIGURE 18 - CONFIDENCE INTERVAL COVERAGE 100 % COV e ISE:RVEO 8 ~ t UTIO e , ADJUSTED ! + 80 - + + 60 + 40 - :t + + 20 0 + + + + + .1 0.5 0.6 0.7 O.B nl/n2 FIGURE 1C - COMPARISON 2.25 + 0.9 1 OF MSE ,",SE(AOJ)!WSE(OBS) 21.751.50 1.25 10.75 0.50 0.25 0 , • •I •• •• 0.5 0.6 • • • I • I • • • 0.7 0.8 nl/Tr2 0.9 • •• • RATIO ¢ �1hl Drummer ESTIMATION OF PROPORTIONS fiGURE 2A - PERCENT BIAS 60 50 40 30 20 10 0 - A~J. PROP. Q "" + _.. .•. .•. -10 -20 -30 1- OBS. P~OP. % BIAS - ••• ••• •• Q •• "''''' 1 •• ~ ..:I .•••• "" , 0.7 O.B ! .2 1.3 n2/TT- ~ A'~ 0.9 1.1 1.4 1.5 FIGURE 28 - CONFIDENCE INTERVA:... COVERAGE I # 0 80 + 60 - !. t:t + *'8- T- + + t + + + + + + + + + * 0.7 O.B + + + + , 0.9 : .2 1.1 • .;- + , I n2/TT- '~H 1.3 ,l. 1.4 + "'SE(AO~)NS£(OeSI 1 • 75- ,! 1 • 501.25 - • • 10.75 - 0.50 - 0.25 - -• •• -•• • 0 0.7 O.B :).9 - I •• • .- , -is 1.1 n2/TT- 1.2 I 1.3 (lAIt.. 1.4 I I 1.5 FIGURE 2C - COMPARISON OF MSE 2 ¢ .;- + + ADJ. °ROP. + + + + 20 0 ~ + 40 - -t CBS. P~~P. % COV 100 • 1.5 I �162 Drummer Detecting Unequal Sampling Probabilities From previous discussion, it is important to determine which, if any, of the classes differ regarding their respective overall probabilities of detection. We desire to test the hypothesis HO : ft1 c ft2 = •.• = k• ft If it can be assumed that all k detection functions are of the same parametric form, then the above hypothesis can be tested by testing HO : c1 = c2 = ... ck ' which can be accomplished by, say, a likelihood ratio test, or other procedures, depending upon the postulated detection function. For example, if one assumes that all detection functions are of the negative exponential type, the hypothesis tests the equivalence of k exponential distribution parameters. At the minimum, the analyst should compare the estimated probabilities of detection for the classes. A number of procedures can be used to test for the equivalence of the distance distributions for the classes, although this is not equivalent to testing the hypothesis of equal detectability. The observed distance distributions are affected by both the overall detect ability and shape of the detection curve. homogeneity. One such test procedure is the chi-square test of The procedure is particularly useful because it can be extended to examine the influence of several factors on detectability through the use of log-linear analysis (Bishop, Fienberg and Holland, 1975). Let g(x,y) represent the probability of detection of an item at perpendicular distanc~ x and possessing attribute Y which may influence detectability. For example, Y might represent an activity level (say a bedded animal vs. a standing animal) or group size if the population of interest consists of groups of individuals. If the attribute Y does influence detect ability, then under fairly general conditions, this attribute and the distance data will exhibit some sort of relationship. If the attribute Y does �163 Drummer not influence detectability, then it is easily shown that X and Y will be independent. This argument extends easily to the case where several attributes, say Y1, Y2, ••• , may be influencing detectability. Thus, an attribute exhibiting a relationship with the distance data may be influencing detectability. The general conditions previously referred to require that the detection function g(x,y) is not factorable. That is, if distance and Y independently influence detect ability so that g(x,y) remain independent. = g1 (x) . g2(y), then X and Y will This may occur at small distances from the transect. For example, if Y represents group size, it may not exhibit much of an influence at small distances. However, at greater distances, it is likely that this influence increases, so that X and Y interact, and g(x,y) is most likely not factorable. �164 Drummer The Clustered Population Problem We assume that the population consists of N identifiable groups, or clusters of items, and that each group may consist of items from more than one of k classes. n umb er 'tems 0f ~ Let the random variable T,~ (i = 1, 2, .•. N) denote the total 'th e ~,th custer, 1 ~n the jth class (j = 1,2, and 1et Yij denote the numb~r of items of ••. k) in the ith cluster, with T, = I: y, '. It is ~ j=l ~J desired to estimate the ratio of the number of items in, say, class A to the number of items in class B, = YA/YB (12 ). ' where YA and YB denote the mean number of items in class A and B, respectively, per group. For example, small groups of large game mammals may consist of animals in various age-sex classes, and it may be desired to estimate the ratio of young to adult female animals. The group size problem in line transect data has been addressed by Quinn (1979), Pollock, (1985), Rao and Portier (1981), and Drummer and McDonald (1987). It is assumed that the probability of detecting a group is a function of the number of individuals in the group and also the perpendicular distance from the transect to the geometric center of the group. In order to estimate the total number of individuals in the population, an estimate of the mean group size, E(T), is required. Since the probability of detection of a group is a function of its size, the observed group size distribution is distorted, �165 Drummer and hence the observed mean group size is a biased estimator of E(T). Quinn (1979) proposes post-stratification by group size as a means to alleviate the group size influence and to obtain an unbiased estimate of the mean group size. The other approaches involve the use of bivariate detection functions which incorporate both the distance and the group size variables. k For the ith detected group of size ti 1: y, , , let ~) E j=1 y., = ~ (yil' Yi2' ..., Yik) denote the group mix, or composition. It is possible that the probability of detecting a group is a function of its mix, as well as its size and distance from the transect. For example, in the previous discussion, the chance of detection could vary with the proportion of young animals in the herd. Let g(') represent the probability of detecting a group from the transect. We consider three cases for the form of the detection function g(') . In each instance, the observed group composition and group size distributions are examined in order to determine an appropriate estimator. The relevant distributions are derived in Appendix A. Case I: g(') = g(x) ; the probability of detection of a group is a function only of its perpendicular from the transect, x, and is independent of both group size and group mix. In this case, both the observed group composition and group size distributions are equivalent to the respective true distributions. Thus, the observed ratio n r" AB = 1: YiA i=1 -..-........n~= YA/YB 1: i=l is the recommended estimator. Y'B ~ The variance of "rAB can be estimated by the usual variance estimate of a ratio estimator. .. " �166 Drummer Case II: g(.) = g(x, t) ; the probability of detecting a gr01lpis a function of its distance from the transect and its total size, but is independent of group composition. In Appendix A, it is shown that both the size and composition distributions are distorted by the detection function. However, the conditional distribution of group composition given group size is not distorted. This suggests that post-stratification by group size will sufficiently adjust for the group size influence. Let m denote the number of group size classes formed by poststratification, with corresponding overall probability of detection 2L th nr = cr (r = 1, 2, ... m). In the r class, nr groups are detected, and x- YrA and YrB are the mean number of items in class A and B per group in the rth group size class. An estimate of the ratio rAE is given by m I: r=l " rAE * = m I: r=l nr YrA " -1 cr " " = NA/N B " -1 nr YrB (oH) cr Quinn (1979) notes that m I: r=l m I: n r . YrA nr . c"r -1 " -1 cr r=l " * is an unbiased estimator of YA (conditional on c"r-1). Thus rAE is the ratio - of two approximately unbiased estimators. An estimator of the approximate variance of r" AB* is given in the Appendix. Case III: g(.) = g(x, X, t) ; detect ability is influenced by both a group's size and its composition. It is shown in the Appendix that unless ~g(x, X, t)dx can be postulated, then the relevant distributions cannot be determined. research. Thus, this case is unresolved and remains a problem for future �167 Drummer An Illustration The study area is in NW Colorado characterized by the sagebrush steppe habitat type. The small community of Great Divide, located roughly in the center of the area has the highest elevation of 2,240 m. The elevation generally decreases in all directions from Great Divide and there are numerous dry and intermittent drainages radiating in all directions. The lowest point of the area is at the village of Maybell with an elevation of 1,804 m. The area is generally semi-arid with cattle and sheep grazing as the predominant land use. The topography is moderately rolling, and, where the terrain permits, winter wheat is grown in very irregular shaped fields. These data are from a modified strip transect survey of pronghorns (Antilocapra americana) conducted by the Colorado Division of Wildlife, during August 1985. A Bell-Soloy helicopter flown 30 m above the ground and at 60 knots served as the observation platform. The area was arbitrarily divided into 3 roughly equal strata to ensure distributive sampling. Within each stratum, transects 1.6-km wide were randomly selected with the constraint that one 1.6-km wide transect must separate any two adjacent selected transects. This was to maintain the independence of the observations on each transect. Approximately one-third of the total area was sampled. The center-line of the transect was the line-of-flight and 0.8-km on each side of the helicopter was searched. The crew consisted of the pilot, an observer/navigator, and the primary observer. When a group of pronghorns was located, the primary observer estimated its distance from the flight-line in 100-m increments and recorded the activity (bedded, standing, or running) of the group when it was first spotted. Unlike the strict line transect methodology, we diverted from the flight-line and pursued the group to within close range to obtain an accurate �168 Drummer count and classification of the group members. Any groups observed while returning to the flight-line were recorded but not included in the sample. Thus, the data could be treated as a line transect data set. The information, by group, was recorded on a portable tape recorder and later transcribed. Flights were begun at sun-up and continued through the day. A total of 237 herds, ranging in size from 1 to 24 animals, were detected during the sampling process. either bucks, does, or fawns. fawns to does were desired. The individuals in the herds were classified as Estimates of the ratio of bucks to does and A large number of herds (64) could not be accurately classified as to activity. Since it was possible that this phenomenon did not occur at random, these herds were included in the detectability analysis. The first phase of the analysis consisted of a log-linear analysis of four variables to determine which of these factors influenced detectability. The four variables examined were herd size, distance, herd activity, and herd composition. herd. Herd composition was defined as the proportion of bucks in the For the purposes of the log-linear analysis, cut-points were established for the distance, herd size, and herd composition variables. Numerous sets of cut-points were tried in order to examine their influence on the analysis. Also, three-dimensional analyses were performed to guard against spurious results due to sparse data. However, the results of the hypothesis tests were not influenced by the choice of cut-points nor sparse data. Based on the tests of simultaneous interaction and marginal and partial association (Brown, 1976), statistically significant relationships were found between the distance and herd size variables, and also between the herd size and herd composition variables. A two-dimensional analysis revealed that larger herds tended to be detected at greater distances from the transect �169 Drummer than did smaller herds, indicating that the probability of detection was an increasing function of group size. Also, the large herds tended, on average, to be comprised primarily of does and fawns, while, smaller herds tended to consist of bucks. Herd activity exhibited no relationship with the distance variable, and exhibited a weak relationship with the group size variable. The three way relationship between herd size, herd composition, and distance was insignificant, indicating that, conditional on herd size, distance and herd composition were independent. It was concluded that post-stratification by herd size could be used to obtain an overall density estimate and estimates of the sex-age ratios. Table II contains the summary statistics for the herd data. Assuming equal detect ability for groups of all sizes, the buck to doe ratio can be estimated by ~ rBD with a standard error of 0.05435. YB/YD = = 0.43 The fawn to doe estimate, unadjusted for group size influence, is ~ rFD = YF/YD = 0.86 with a standard error of 0.0555. Since the does and fawns tended to exist in large groups and therefore were more likely to be detected, one would suspect that the observed buck to doe ratio is low. Table III contains the summary statistics for the post- stratified ratio estimators. (m = Four herd-size categories were defined as 4), and the Fourier Series estimator (Crain et al., 1978) was used to estimate D r , the herd density for the rth herd size class (r = 1, 2, 3, 4). A The program Transect (Laake et al., 1978) was used to obtain Dr and its variance estimate. We note from column (3) of Table III that the estimated overall probability of detection of herds tends to increase with herd size, as �170 Drummer expected, although herds of size 3-4 had the highest estimated probability of detection. A A A In Table III, the symbols DB ' DO ' and OF denote the estimates of the ~A~~ buck, doe and;:~sity, respectively. The post-stratifcation ratio estimates are A A DB/Do = 0.48 (SE = 0.0663) and A * A A rFD = OF/Do = 0.87 (SE = 0.0505) As expected, the post-stratified estimate of the buck to doe ratio is greater than the observed ratio, although the difference here is very small. The disparity between the estimators depends upon the variability in herd sizes, the extent of the herd size's influence on detectability, the degree that members of the different classes associate with one another, and the level of pooling required in order to obtain reliable density estimates. The observed fawn to doe ratio and post-stratified estimates are nearly identical. Recall that fawns and does tended to associate with one another, and thus were sampled with approximately equal probability. The large correlation (0.726) between the number of fawns and does per herd is evidence of this association. The standard errors of the post-stratified estimates are comparable to those of the observed ratios. This comes about because even-though the post- stratified estimators require additional parameters, the post-stratification tends to reduce the variance in the mean herd size variable. is needed regarding properties of this estimator. Further research �171 Drummer Table II SUmmary Statistics for Sex-Age Ratio Estimators Statistic Does - Fawns ~ mean per group 2.26 1.95 0.975 std. dev , 2.58 2.25 1.484 Bucks ~ Fawns 1.000 -.105 -.162 1.000 .726 Correlation Xatrix per herd) (!I Bucks Does Fawns 1.000 Table III Summary Statistics (1) Herd Size for Post-Stratified (2) (3) " of Herds Estimated PR(Detection) Sex-Age Ratio Estimators (4) (5) Estimated Herd Density(SE) 0 Xean 2er He rd Bucks Does YrB r Fawns YrO :rF 1-2 74 0.0834 0.2797 (0.03695) 0.7432 0.3514 0.2703 3-4 68 0.1509 0.1420 (0.02267) 0.5588 1.3529 1.3382 5-7 40 0.0906 0.1392 (0.02463) 1.2750 2.3500 2.3250 8-24 55 0.1309 0.1324 (0.02555) 1.5816 5.8727 4.6727 4 Os = ) D • v r=l r . rB - 0.6742 (SE ; 0.0847) - 1.3951 (SE :II: 1.2079 CSt •• 0.1499) 4 ~ oD K ~ L r=l D'v r 4 ~ D F '\ - . 0 • v ;.. r - rF K 0.1756) r=l ~ * rFD ·rD = ~ OF/DO - 0.87 (SE ••0.0505) • �172 Drummer APPENDIX A Derivation'of Distribution Results for the Clustered Population Problem Let variable Y. h(t) T. denote the probability density function for the group size and let We note that g(y) g(y) can also be represented through the use of a contagious distribution. g(Y) where fey: t) E denote the density function for the group mix That is. ff(ylt)h(t)dt (1) • 1s the density function of the group mix conditioned upon group size. Let (x , w(x. y. denote the joint observed, or weighted distribution of t) Y, t), .,ith corresponding marginal distributions Case I: g(o) = (y. t) , w2(~) • and g(x) From the theory of .,eighted distributions w(x, y. t) '10'1 (~ahfoud and Patil. 1982); = g(x)f(y't)h(t) :: ..':5(X)f(y t)h(t)dxd..:::. dt = g(x)f(y:t)h(t) (2 ) c where c = :g(x)dx. The joint observed distribution of (.:::_. t) is given by (3) which yields 'W (v) 2 ~ = g(y) - and w (t) 3 z h(t) . Thus, i~ this case, the group size and group mix distributions are not distorted by the sampling procedure. Thus YA and YB are unbiased estimators of YA and YB, respectively. �173 Drummer Case II: g(.) ·g(x,t) We aga~n consider the observed distributions. From the previous discussion, w( x -r- t) • -:-::-_-=-g_(-:-x_, _t)~f_(1.~1 t_)_h_( t_) _ ff ... fg(x,t)f(v'" it)h(t)dxdv dt _ = = where ~(t) == g(x,t)f(v't)h(t) "-:. f(y·t)h(t)Ht)d~ dt g(x,t)f(;lt)h(t) fg(x,t)dx and (4) e e = :f(~:t)h(t) ·:'(t)d~ dt. JO ••• This yields the following marginal distributions: wI (r, t) = f (.:::_: :)h(t) ~(t) _- e .·:(':::_!t)h(t) ~(t)dt ( 6) e and w (t) = :f(Z.:t)h(t)~(t)dv 3 = h(t)~(t) e e It is evident that both the group mix and group size distributions torted by the sampling procedure. distri~ution ( 7) are dis- Consider, however, the observed group mix conditioned on group size. w 4 (v:t) = f(v't)h(t)!(t)!8 .•.... h(t):;'(t)/e From (5) and (7). = f(~.t) ( 8) Thus, the conditional distribution of sroup composition given group size is not distorted ~y the sampling procedure. ratio esti~ator. This suggests the post-stratified �174 l.)rummer Case III: g(.) - g(x.y,t) Let 'f(l..t)- fg(x,z,t)dx, and let y - :: ••• fg(x,Z,t)f(Z!t)h(t)dx d_y. Then w(x,y,t) - g(x,Z,t)f(ylt)h(t) y wl(y,t) - '-¥(v,t)f(y't)h(t) y w2(z) • :f(Z,t)f(y!t)h(t)dt y w 3 (t) = h (t): ~(y.t)f (: 't) d::::. and y This yields w 4 (vit) ._, = -ev,t)fev '~(l' Thus, unless the f cr-a of distributions t) . ~C.;:_, t )f(Z-t....• )~d-.;:_ t) = :g(x, y. t)dx is known, the desired cannot be determined. APPE:\DIX B Variance Estimation for Post- Stratified Ratio Estimators Let m n herds in the with r denote the number r th of post-stratification class (r = herd size classes, m). 1, 2, ... v - rA Let and ? S- rA denote the sample mean and variance of the nu~ber of class A items per herd in the r th herd size class. Let D r denote the estimated density of ~ o. herds in the rth herd size class, with of the overall density of class A items. independent, and that observations independent, then D = A r=l D r . Assuming that .'rA , the estir.tace D r and YrA in different herd size classes are are �175 ". Drummer m m Var(DA) • Var( I D·y )r rA r-l I r-l Var(D r .y rA) (1) + Var(D ).Var(Y ) } , r rA where Var(yrA) • S;A/nr. The desired ratio estimator is with approximate variance estimated by ~* Var(rAB ) ~* = ( rAn ) 2 { Var ~ (D.;) ~ . + ? (D )A - 2 Cov( DA, DB) ( 2) CDA • DB) m !!l ; \' - D . D·v : Cov(YiA, YjB) = 0 for r=l By assumption, (i, j) E Cov(Di, D ) j { 1, 2, ... m } c r V • _ - r A.' r= 1 • Taking expectations (and cancellation) yields m + I r=l Var(D ) • E(YrA) • E(YrB) r r - rB i * j , where �176 Drummer Substituting the observed sample moments yields m cOv(DA' DB) · r-l I [C~v(yrA' m + I Var(D ) r rzl ~ ~ YrB) . { Var(D ) + r } . YrA . YrB (3) ~ ~ Var(D ), Var(D ) , and CQV(D , DB) A B A the desired estimate. Substitution of (Dr ) 2 into (2) yields �177 Drummer Literature Cited Bishop, Y. M. M., S. E. Fienberg, and P. W. Holland (1975). Discrete Multivariate Analysis. MIT Press, Cambridge, MA. 557 pp. Brown, M. B. (1976). Screening effects in multi-dimensional contingency tables. Applied Statistics (25), 37-46. Burnham, K. P. and D. R. Anderson (1976). Mathematical models for nonparametric inferences from line transect data. Biometrics 32: 325-336. Burnham, K. P., D. R. Anderson and j. L. Laake (1980). Estimation of density from line transect sampling of biological populations. Wildlife Monograph No. 72. 202 pp. Crain, B. R., K. P. Burnham, D. R. Anderson and J. L. Laake (1978). A Fourier Series Estimator of Population Density for Line Transect Sampling. Utah State University Press, Logan, Utah. 23 pp. Drummer, T. D. and L. L. McDonald (1987). Size-bias in line transect sampling. Biometrics 43(1): 13-21. Gates, C. E., W. H. Marshall, and D. P. Olson (1968). Line transect method of estimating grouse population densities. Biometrics 24(1): 135-145. Gates, C. E. (1969). Simulation study of estimators for the line transect sampling method. Biometrics 25(2): 317-328. Laake, J. L., K. P. Burnham and D. R. Anderson (1979). User's manual for program transect. Utah State University Press, Logan, Utah. 26 pp. Mahfoud, M. and G. P. Patil (1982). On Weighted Distributions. In Statistics and Probability: Essays in Honor of ~ ~ Rao, Kallianpur, ~, P. R. Krishniah and J. K. Ghosh (eds.). North-Holland Publishing Company, New York. pp. 479-492. Pollock, K. H. (1985). Unpublished manuscript; 12 pp. Quinn, T. J. II (1977). The effects of aggregation on line transect estimators of population abundance with application to marine mammal populations. Thesis. University of Washington, Seattle, Washington, USA. Quinn, T. J. II (1979). The effects of school structure on line transect estimators of abundance. In Contemporary Quantitative Ecology and Related Ecometrics, Patil, G. P. and M. L. Rozenweig (eds.). Internatt. Co-op. Publ. House, Fairland, MD. pp. 473-491. �178 Drummer Quinn, T. J. II and V. F. Gallucci (1980). Parametric models for line transect estimators of abundance. Ecology 61: 293-302. Rao, P. v., K. M. Portier, and J. A. Ondrasik (1981). Density estimation using line transect sampling. In Estimating Number of Terrestial Birds, Ralph, C. J. and J. M. Scott (eds.). Studies in Avian Biology No.6: 441-444. Cooper Ornithological Society, Allen Press, Lawrence, Kansas. Seber, G. A. F. (1982). The Estimation of Animal Abundance, MacMillan Publishing Company, New York, New York, 654 pp. �179 APPENDIX B EVALUATION OF CENSUS TECHNIQUES Thomas M. Pojar, David C. Bowden, FOR F'RONGH2RNS and Bruce Gill OUTLIN~ I. Introduction ~. Status and need. B. Crecits II. Description of study arE~S A. Shortgrass pralrie B. Sagebrush steppe III. Methods A. Transect strip width B. Sampling systems and intensities 1. Strip transects anj line transe=ts 2. Random quadrats C. Searc~ techniques a,d data recording 1. Strip transects 2. Random quadrats 3. Line transects D. Test fer accuracy in quadra~ SE~rch IV. Results A. Transect strip width 1. 800m width vs. 1600m width 2. Comparison with data from line tr~ns2cts shortgrass prairie. B. Strip transect vs. random quadrat 1. Population size and preCision estimates 2. Herd structure and precision estim~te5 3. Differences in results from two habitat types C. Quadrat search accuracy V. Conclusions and recommendations VI. Literature Cited in ��Colorado Division ot W11d11ie Wildlife Research Report July 1988 181 JOB PROGRESS REPORT State of Colorado Project No. W-153-R-2 -----------------------No. 3A ---------------------- Mammals Research Work Plan Pronghorn Investigations Habitat Selection and Population Performance of a Pioneering Pronghorn Population Job No. 2 Period Covered: July 1, 1987 - June 30, 1988 Author: T. M. Pojar ABSTRACT Except for rate sightings of 1 or 2 pronghorns (Antilocapra americana), Middle Park Colorado has been devoid of this species since the 1920s. Beginning in the early 1970s, pronghorn sightings were reported with increasing frequency, and by 1979 pronghorns were reported seasonally throughout the year. The largest number sighted since the report of 7 pronghorns in the 1920s was on 21 August 1979, when a group of 13 was seen 10 mi north of Kremmling in the area of Antelope Pass. The population expanded through reproduction, which indicates that this is likely a bona fide pioneering popultion. As of December, 1986, the herd totaled 80 animals with a structure of 36Bucks:lOODoes:77Fawns (determined from trapped animal). A portion of the herd was trapped using a corral trap, and 9 radio collars were put on yearling and adult females, the remainder of the adult does were collared with numbered, yellow, plastic collars and numbered eartags. Five of the 8 yearling/adult males captured were neck collared and eartagged; the remaining 3 males and all fawns were eartagged only. .In total, 47 animals were trapped and marked. The radioed animals have been.located bi-weekly beginning in January, 1981' (ca 40 locations. .on each animal). One radioed doe was killed in an automobile collisibIi·0014 July·19B7 ab~ut,l mi east of KremUu.ing•. AIiother radio ceased to function in April, 1988. In .October, 1987, a sample of 63 pronghorns were classified from the ground; the ratios were 54B:lOOD:7lF. A ground count of the total popul.atIon on 14 December 1987 was 122, which was verified by aerial photography frow a helicopter within 2 hrs of the ground count. ��183 HABITAT SELECTION AND POPULATION PERFORMANCE OF A PIONEERING PRONGHORN POPULATION Thomas M. Po jar P. N. OBJECTIVE Describe population dynamics and habitat use of a pioneering, expanding pronghorn population. SEGMENT OBJECTIVES 1. Describe seasonal and annual distribution of the Middle Park pronghorn population. 2. Determine sample sizes of radio-collared animals and observations necessary to describe habitat preferences. 3. Monitor population dynamics of Middle Park pronghorns with: a. Ground counts to describe changes in population size. b. Ground counts to quantify population sex-and-age composition. ACKNOWLEDGMENTS The trapping operation was facilitated through the efforts of S. Steinert, J. Gerrans and Area 9 personnel, R. Spowart, J. Claassen, R. Firth, A. Chappell, B. Thompson, B. Sigler, M. Middleton, J. Hicks, and J. Frank. C. Cesar and other personnel from the Kremmling Bureau of Land Management District provided able assistance during trapping. J. Hill permitted the trapping operation on his property. J. Ritchie, B. Adrian, and M. Miller assisted in collection and handling of pronghorn blood samples. J. Ellenberger and the CDOW NW Region contributed in the form of helicopter time and 5 radio transmitters. STUDY AREA Middle Park is a·high mountain park that is bordered on the west by the Gore Range, on the north by the Rabbit Ears Range, and on the east and southeast by the Continental Divide (Tiedeman et ale 197). Kremmling (2,361 m) is more or less centrally located and is the major municipality in the Park. The lower elevation of the Park is predominantly big sagebrush (Artemisia tridentata)/western wheatgrass (Agropyron smithii) plant community and ranges in elevation from 2,200-2,750 m with slopes from 0-20%. Aspen (Populus tremuloides) and conifer communities are found above 2,750 m (Tiedeman et ale 1987) • �184 Precipitation averages 35-40 cm annually and is evenly distributed throughout the year. Mean annual temperature is 4.60C (Tiedeman et ale 1987). Severe winter conditions occur periodically in Middle Park with deep snow and long perods of extremely cold temperatures. These conditions result in population mortality of 50% or greater on other ungulate species in the park (Carpenter et al. ND). METHODS AND MATERIALS The pronghorns were trapped using a coral trap following the trapping and handling procedures sanctioned by the Pronghorn Antelope Workshop (Anonymous 1984). Tracking was done either from the ground or from an airplane. In either case, animal location was recorded on a 15 min topographic map to the nearest quarter mile. Herd structure estimates were made from the ground during late summer and early autumn using 8 x 44 binoculars and a 20-40X spotting scope. Attempts were made to classify at least 50% of the population. Total population size was estimated from the ground in winter when it was assumed that all Middle Park pronghorns were on the wintering area. RESULTS Trapping and Marking The trapping operation was conducted 16 December 1986, and 47 animals were captured. Radio transmitters (Telonics) were put on 9 yearling/adult does. Light-weight, yellow, plastic collars with numbers were put on all remaining yearling/adult does. This same type of collar was put on 5 of the 8 yearling/ adult bucks captured, and the remaining bucks and all fawns were eartagged with numbered yellow tags (Appendix A). All 47 animals were marked in some fashion. There were no trap mortalities or injuries, and all of the neck-collared animals were verified to have survived at least through September, 1987. All of the radioed does were alive as of 30 June 1988 with the exception of radio frequency 149.370. This animal was killed by an autmobile on a county road about 1 mi northeast of Kremmling on 14 July 1987. The doe with radio frequency 149.290 has been verified as being alive, but the radio ceased functioning during April, 1988. Observations of Marked Animals Pronghorns with yellow eartags were observed in the Grandby area, which is approximtely 30 air mi east of the trap site. In early May, 1987, Bob Thompson (DWM Kremmling) reported seeing 4 animals, 3 with eartags, North of Grandby; and Mac and Mrs. Rienhoff reported 4 pronghorns, 3 does, and 1 buck (horns about the length of the ears), all with eartags. In early June, 1988, Ron Scott (USFS) saw "about" 12 pronghorns near Grandby. He did not notice any eartags or collars, but he only observed them as he drove past in a vehicle. An unmarked buck was apparently killed by a vehicle on Highway 9 near Green Mountain Reservoir in late August, 1987) (J. Liewer, pers. comm.). The location of the kill (TlS,R80W,Sec 2) is about 12 air mi from the trap site. �185 A doe with ear tag number 23 was observed near Coalmont (T7N,R8lW,Sec 24) (S. Steinert, pers. comm.), which is in North Park, about 35 air mi north northeast of the trap site. This is the first evidence of interchange between Middle and North Park, although it is presumed that the original Middle Park pronghorns immigrated from North Park. Locations of Radioed Animals All of the radioed does remained within 10 mi of where they were trapped, most much closer. Based on about 40 location points for each animal, the movements were mostly to the north (Figs. 1 and 2). The legal description of each location will be converted to points on a Universal Transverse Mercator grid (U.S. Army 1973). The task of converting to the UTM grid is completed for locations through November, 1987. When the conversion process is completed, this series of points will be used in the program McPAAL (Stuwe NO) to delineate the seasonal and annual area of habitation for each animal based on the minimum convex polygon. An example of the results of this procedure is shown in Figure 1, which includes location points for the doe with radio frequency 148.390 from January through November 1987. The winter (Jan-Mar) area of habitation for this animal was 7.5 kmi (2.9 mi2) and the yearlong (Jan-Nov) area was 66.2 km2 (25.6 mi2). The distribution of radioed animals on 16 June 1987 is shown in Figure 2. All of them, except 2, are within 3 mi of the trap site. Typical winter distribution was within 3 mi of the trap site for all of the animals (Fig. 3). Population Size and Structure Prior to the trapping operation, the presumed total population in Middle Park was 80 animals based on counts of the major group inhabiting the wintering area. The sex-and-age ratios of the 47 trapped animal was 36B:lOOD:77F; if it is assumed this is representative of the population, then there were 14 bucks, 37 does, and 29 fawns in December, 1986. The winter population for 1987-88, based on several ground counts and aerial photography (14 January 1988), was estimated to be 122 (Fig. 3). The herd structure obtained from classification (ground) of 63 animals on 14 October 1987 was 54B:lOOD:7lF. Applying these ratios to the population of 122 gives 29 bucks, 55 does, and 38 fawns. Of the 55 does, 40 would be of reproducing age, which gives a fawn:lOO mothers ratio of 95:100. During the winter of 1987-88, several attempts were made to get a total count of yearling and mature bucks. The highest count of 25 was obtained on-14 January 1988. Assuming that this count is more accuratp. than extrapolating from the 14 October buck:doe ratio estimate, then the total number of does and fawns would be 97 (122-25-97). This could be apportioned into 40 fawns (20 males and 20 females) and 57 does using the 14 October classification of 7lF:lOOD. This restructuring of the population results in ratios of 44B:lOOD:70F. Using these ratios and assuming no natural mortality (which is not realistic), the population size and structure of the fall 1988 population can be projected. In June of 1988, yearlings and 57 tribute 95 fawns by fall of 1988, the female side of the population would be composed of 20 reproducing-aged animals. If reproducing-aged females conper 100 does, then 54 fawns will be added to the population and the total will be 176 animals composed of: �186 Bucks Does 25 Mat. 20 Yr1. 57 Mat. 20 Yrl. 54 45 77 54 Fawns Total 176 If it is assumed that the count of 80 pronghorns in December of 1986 was, in fact, the total population in Middle Park and that there was no immigration or emigration, then the annual rate of increase between 1986 and 1987 was 55%. LITERATURE CITED: Anonymous. 1984. Management guidelines: Trapping and translocation. of Pronghorn Antelope Wkshp. 11:237-251. Proc. Carpenter, L. H., R. B. Gill, D. L. Baker, and N. T. Hobbs. ND. Colorado's big game supplemental winter feeding program, 1983-84. Colo. Div. Wi1d1. Xerox, Appendix. 92pp. Stuwe, M. ND. McPAAL micro-computer programs for the analysis of animal locations. Program Documentation. Cons. and Res. Cntr., Nat1. Zool. Park, Smithsonian Inst., Front Royal, VA. Printout. lapp. Tiedeman, J. A., R. E. Francis, C. Terwilliger, Jr., and L. H. Carpenter. 1987. Shrub-steppe habitat types of Middle Park, Colorado. USDA For. Serv., Res. Paper RM 273. 20pp. U.S. Army. 1973. Technical manual: Universal transverse mercator grid. H.Q., Dept. of Army, Washington, DC. No. 5-241-8. 64pp. ™ Prepared bY'ib&, e~~ Thomas M. P jar Wildlife Researcher z �187 Figure 1. Winter (Jan-Mar, solid line) and year-long (1987, dashed line) home range of mature pronghorn doe with radio 148.39~. Minimun convex pqlygon (Program McPAAL, Stuwe ND) is 2.9 miles 2 (7.5 km2) for winter and 25.6 miles2 (66.2 kmf for year-long area of habitation. �188 KRE""'LI~;C QUADRANGLE ':~:"jP":"J-C~"'''': .::- _~ 0j)2 ".--~ .. 11fS.~ ... ",1-': - . ..r-~_:-' =>:..•. Figure 2. Location of the radioed pronghorns on 16 June 1987. This distribution represents typical summer dispersal. The numbers are radio frequencies. �189 'J ~~., D,-"-' /"',,: ... 13:':1 '" '-'j "'. .,...-tI .'..;; r\ ~ 18/ a"", .•..•••.• 'I'~ ......._ I .~. -.. __-------...::,_,-~jl . -.;;<'- II ;,---) [1"'\ I .7656. ~ - •.~ ''-, ..-. -, iI .~ '-:'[;.' " \,""J"! :_;,....!~,~. ':> i -: ;-;;-;.:-,:--UT/2 .•.• _u 124 I' \ ,: 1ci ,/ J " P, •.~•.• \.c·'""t' ,_:...- . .' - ..,., - .,'" ---- :-'- --.ii:i,i;::L--1:;,:_;" ~'I .~:n =]. --~- - ~- : !"r-'==r-=-~ , Kremmling • ,/ , /~ j,;c. _ L Figure 3. Dates and total counts of the wintering group of pronghorns during January, February, and March 1988. All radioed animals were in this group. ��APPENDIX A 191 BANDING AND TAGGING RECORD Species: Pronghorn (Antilocapra americana) Date: 16 Dec 1986 Trap site Name:~M~i~d~d~l~e~P~a~r~k~ _ Trap site Location:~C~u~r~ry~~R~a~n~c~h~ _ Legal Description: R80W,T2N,Sec 36 (SW 1/4) Nearest Town:~K~r~e~mm==1~1~'n~g~ ~ capture Method: Wing Trap wI curtains Purpose: Define Tag Number Neck Ear seasonal and annual home range Sex Age Comments 1 2 3 4 radio radio none radio F F M F A A F A Blood yes yes yes yes 5 7 1 3 radio M F F A A A yes yes yes 8 9 2 radio M F Y A yes yes 10 radio F A yes 11 none F A no 12 radio F A no 13 14 15 16 17 18 19 20 radio 4 5 11 6 7 8 radio F F F F F Y A A A A Y A A yes yes yes no 21 22 23 24 25 9 10 none 12 13 Y A F A Y yes no no no no 6 M M F F M F F F _ Freq. 148.420 Freq. 148.390 Obs. Freq. 148.400 12/17/86 - ok Observed 12/17/86 - ok Freq. 148.440 12/17/86 - ok Obs. Obs. Freq. 148.430 12/17/86 - ok Obs. Freq. 149.210 12/17/86 - ok Weak when released - shock and/or exhaustion. Obs. Freq. 149.250 12/17/86 - ok Freq. 149.370 ye'F yes yes yes Freq. 149.290 12/17/86 - ok Obs. �192 Tag Number Ear Neck 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 14 none none none none none none 15 none none none none none 16 17 none none none none none none none Sex F F F A F F M A F F F M M F F Comments Age A Y F M M Y M F F F F M F M F F F F F F A A F F F F F F F Blood no no no no no no no no no no no Void tag number no no Tag in left ear. no no no no no no no no no SUMMARY OF CAPTURE Fawns 6 MALES Yearlings 3 Mature 5 = 14 FEMALES Fawns Yearlings Mature 11 4 18 = 33 Total pronghorns trapped = 47 RATIOS OF CAPTURED PRONGHORNS BUCK:I00DOE = 36.4 FAWN:I00DOE = 77.3 �Colorado Division of Wildlife Wildlife Research Report July 1988 193 JOB PROGRESS REPORT State of Colorado Project No. W-153-R-2 -----------------------No. 6A ---------------------- Mammals Research Work Plan Mountain Lion Investigations Job No. 1 Period Covered: July 1, 1987 - June 30, 1988 Author: Mountain Lion Population Dynamics A. E. Anderson Personnel: See Acknowledgments ABSTRACT Five puma (Felis concolor) were captured for the first time, and 5 radiocollared puma died. Seven, mature radio-collared males were recaptured for blood, tissue, and semen sampling, and a mature female was recaptured and recollared. Since 1981, 57 puma have been handled, and 29 have died. The major causes of death were sport hunting outside the study area (7) and capture (9). The mean + SD number of days from capture to death for 11 male and 9 female puma were 307.0 + 221.2 and 458.2 + 358.6, respectively. Young «24 months) puma comprised 61.4% of the total sample. Sex ratios for individual and combined age classes did not differ (P < 0.05) from equality for samples of either living or dead puma. ��195 MOUNTAIN LION POPULATION DYNAMICS Allen E. Anderson P. N. OBJECTIVE To assess the effects of sport hunting on mountain lion populations. SEGMENT OBJECTIVES 1. Capture and mark up to 12 mountain lions. 2. Monitor mountain lion movements. ACKNOWLEDGMENTS I thank G. Bock, D. Bowden, G. Byrne, G. Cheney, D. Coven, T. Davis, J. Ellenberger, V. Giba1di, J. Gray, L. Gray, L. Green, G. Hanson, M. Hargis, C. Heacock, R. Henkle, M. Herschcopf, J. Humphrey, J. Kane, D. Kattner, D. Masden, D. McCauley, K. Miller, J. 01terman, S. Parker, B. Poehnert, M. Potter, M. Roelke, D. Rowley, P. Shearwood, M. Stevens, N. Ting, A. Wacker, and J. Wolfe for their assistance. I am also grateful to D. Miller, VicePresident, Research and Education Department, National Wildlife Federation for facilitating financial assistance from the N.W.F. D. Kattner, Project Puma Hunter, deserves recognition for his exemplary efforts as does M. Roelke and staff of the "Collaborative Wild Cougar Project." METHODS AND MATERIALS Methods were described in Anderson (1983a). Eighty-six days were spent hunting from November 18, 1987, to April 29, 1988. Puma were located with aerial telemetry at approximate weekly intervals. Only those locations subjectively judged, on the basis of signal quality, as being within 1.5 km of the actual location are presented in this report. Locations were plotted (+ km) as Universal Transverse Mercator coordinates on USGS county (1:50,000 scale) topographic maps. In an assessment of location accuracy, the arithmetic mean, SD, median, and range of 25 map distances (+ 0.1 km) between estimated and actual point locations were 0.55, 0.88, 0.20, and 0.0 - 4.5 km, respectively, on 5 livi~g and 8 dead radio-collared puma. Capture effort was allocated proportion~l to surface area among 4 pre¥!~usly established strata (Fig. 1 and Table 1). The intent was to ensure that each resident puma might have a similar probability of capture. RESULTS AND DISCUSSION Allocation of Capture Effort As in previous years, we did not achieve the desired proportional allocation of capture effort (Table 1). Variation in hunting conditions and accessibility among strata was largely responsible. �196 Puma Capture, 1987-88 We captured, radio collared, and released 5 puma for the first age, 14 days were required to radio collar 1 puma using hounds Details on their capture and body measurements plus those of 3 handled are in Table 3. In addition, 7 mature radio-collared, recaptured for sampling blood, skin, and semen by personnel of "Collaborative Wild Cougar Project." Puma Telemetry, time. On aver(Table 2). additional puma male puma were the 1987-88 Twenty-six puma were radio tracked during this fiscal year (Table 4). However, only 14 of these were tracked yearlong; the usual locations of 6 were outside the study area, and by 7-14-88, 5 had died. A mature male (#42) was recaptured and released in GMU 25 about 112 km from its capture site in Cottonwood Canyon by P. Shearwood, a volunteer houndsman, D.W.M. L. Green, and others on 1-21-88. Subsequently, Wildlife Biologist G. Byrne obtained 8 aerial locations of #42 from 2-18-88 to 7-12-88 while radio tracking elk in GMU 25 and vicinity. Individual aerial locations for each of the 26 puma are listed in Appendix. Puma Telemetry, 1981-88 Fifty-seven puma have been handled since the study began. They include 25 puma who were (as of 7-14-88) either alive or fate unknown (Table 5) and 29 dead puma plus 3 puma whose deaths were suspected but never verified (Table 6). Only 1 of 9 puma caught in leghold traps, ostensibly set for bobcat or coyote by recreational trappers, was large enough (> 27.4 kg body weight) to radio collar. Hence, marking those animals was generally limited to ear tattoo numbers. The 2 young puma killed by our hounds during pursuit were not marked. They are identified by their dates of death. Puma Mortality, 1981-88 Twenty-nine or 50.9% of 57 puma handled since 1981 have died (Table 7). Among 8 generalized sources of puma mortality (capture-related, legal kill, and unknown causes), accounted for 9, 7, and 6 or 75.9% of confirmed deaths, respectively. Shaw (1977) reported that 11 of 16 puma (68.8%) died and that capture-related causes and sport hunting accounted for 4 and 7 deaths, respectively. His study conditions were similar to ours; that is, the study area was closed to legal hunting, but radio-collared puma were vigorously hunted outside the study area. There were no differences- (p > 0.05) in the equality of the sex ratios of each age class or for both age classes combined. Thus, it is unlikely that the tabulated mortality factors were sex specific. Age-and-Sex Classes, 1981-88 Age-and-sex classes of annual captures include all puma handled (Table radio-collared puma (Table 9), and the survivors radio tracked in 1988 10). Annual sample sizes were highly variable and generally too small analysis of sex ratios within individual or combined age classes. The quencies presented are likely influenced by our deliberate and largely 8), (Table for fre- �197 successful selection of puma weighing at least 27.4 kg for pursuit with hounds. For example, the different age class frequencies of female puma between Tables 8 and 9 are largely due to the exclusion in Table 9 of trapped puma whose body weight was generally >27.4 kg. In Table 8, 35 (61.4%) were <24 months of age and 22 (38.6%) >24 months whereas in Table 9, 27 (55.1%) were <24 months of age and 22 (44.9%) at >24 months. As in our sample of 29 dead puma (Table 7), there were no differences (P < 0.05) either in the equality of the sex ratios of each age class or for combined age classes (Tables 8 and 9). Logan et ale (1986:651) tabulated sex-and-age classes of 58 puma estimated from about 46 captures using hounds. They reported 29 (50.0%) >24 months and 29 (50%) >24 months of age in contrast with our data (Table 7) of 35 (61.4%) and 22 (38.6%) puma, respectively. However, a test for independence of the Logan et al. and our data was not" significant (X2 - 1.95, df - 1, P > 0.05). Logan et al. (1986:650) stated: "The high proportion of young lions on the study area suggested a high reproductive rate, rapid population turnover and frequent immigration of young transients." Whether such an interpretation is valid for puma is unknown. It is instructive to observe that even with more <24-month-old puma captured, this age class comprised only 9.5% of the total known survivors (Table 10). Estimates of Survival Telemetry data can be used to estimate survival (Trent and Rongstad 1974, White 1983, Sievert and Keith 1985). Some of the essential vital statistics for such an effort are listed in Table 11. Mean age and number of days monitored are described statistically for 20 male and 21 female puma captured in GMU 62 (Table 12). The mean number of days from capture to death was 307.0 for 11 males and 458.2 for 9 females. About 21 male and 23 female puma are available for estimates of survival to be presented in future publications. Home Range A manuscript on the dynamics of home range of 2 male and 5 female resident puma through March, 1986, was submitted to the Canadian Journal of Zoology on March 29, 1988. Other than an acknowledgment card dated April 6, 1988, nothing has been learned from the Editor as of July 30, 1988. The strongest data for future analysis of resident puma home range characteristics are identified in Table 13. Cervids Killed by Puma Eight mule deer killed by puma included 1 whose sex could not be determin~d and another whose" sex and age were not determined (Table 14). Of unusual interest is the l6-l7-month-old female found 11-28-87. A st~dy of tracks and the use of radiotelemetry by D. Kattner indicated a small puma had actually killed the deer and ate the heart, lungs, liver, and some ribs. That night, however, the much larger #52 ate much of the remainder. Four days later, only a portion of hide and lower legs remained. Only the smaller puma track was found in the vicinity. Also on 3-3-88, #56, a 35.4 kg female puma, killed a large, mature female mule deer but fed little on the carcass. On 3-4-88 some viscera had been eaten, and 4 days later only the skeleton and hide remained. Tracks in the vicinity indicated that only one puma (#56) had probably fed on the carcass. �198 Since 1981, 68 mule deer and 3 elk carcasses have been recorded as puma victims within GMU 62 (Table 15). Both sex and age could be identified for 48 deer carcasses. Sex ratios differed (P - 0.95) from equality for deer <17 months of age (40:100), 18+ months of age (17.4:100), and for the total sample (26.3:100). "Collaborative Wild Cougar Project" The goal of this Florida-Washington, D.C., based study is to examine genetic diversity among subspecies of Felis concolor and how the endangered Florida form compares to other presumably heterogeneic species. The project is staffed by M. Roelke, D.V.M. - Florida Panther Project Veterinarian, Florida Game and Fresh Water Commission, Gainesville, Florida; S. J. O'Brien, Ph.D. - Laboratory of Viral Carcinogenetics, National Cancer Institute, Frederick, Maryland; and D. E. Wildt, Ph.D.; E. Jacobson, D.V.M., Ph.D.; and J. G. Howard, D.V.M. - Department of Animal Health, National Zoological Park, Washington, D.C. M. Roelke, assisted by S. Parker, and V. Gibaldi, D.V.M., spent 12 days with us from April 17, 1988, to April 29, 1988. D. Kattner and myself (assisted by Roelke, Parker, and Gibaldi) captured 7 mature, male, radio-collared puma, and they processed the puma for blood samples, skin biopsies, and semen samples. In addition, Dr. Roelke performed a field postmortem and obtained clotted blood and tissue and fecal samples from #50 who had died from unknown cause(s) during March, 1988. I expect to receive copies of pertinent data during the next fiscal year from M. Roelke. Because of health and person reasons, I plan to retire July 1, 1989. I will spend the next year analyzing data and preparing publications on relevant information gained during this study. LITERATURE CITED Anderson, A. E. 1983a. Program Narrative Proj. 45-01-503-15050, Work Plan 6, Job 1, Mountain lion population dynamics. 7pp + 3 tables and Appendix A. Colo. Div. Wildl., Fort Collins. 1983b. A critical review of literature on puma (Felis concolor). Colo. Div. Wildl. Spec. Rep. 54. 9lpp. Ashman, D. et al. 1983. The mountain lion in Nevada. Nev. Fish and Game Dept., Fed. Aid Wildl. Restor., Final Rep., Proj. W-48-l5. 75pp. Logan, K. A., L. L. Irwin, and R~ L. Skinner. 1986. Characteristics hunted mountain livn population. J. Wildl. Manage. 50:648-654. of a Sievert, P. R., and L. B. Keith. 1985. Survival of snowshoe hares at a geographic range boundary. J. Wildl. Manage. 49:854-866. Shaw, H. G. 1977. Impact of mountain lion on mule deer and cattle in northwestern Arizona. Pages 17-32 in R. L. Phillips and C. 'Jonkel, eds. Proc. 1975 predator symposium, Mont-.-For. and Cons. Exp. Stn., Univ. Montana, Missoula. �199 Trent, T. T., and o. J. Rongstad. 1974. Home range and survival of cottontail rabbits in southwestern Wisconsin. J. Wildl. Manage. 38:459-472. White, G. C. 1983. Numerical estimation of survival rates from band-recovery and biotelemetry data. J. Wildl. Manage. 47:716-728. Prepared by C. 4-n~ ~ Allen E. Anderson . Wildlife Researcher �200 rab1e 1. ChroDOlogyof p.-a huntil18 effort by .trata, DIlcoapabgrePlateau (QfU 62), represents 1 day of hunting effort. Underlined dates are explained in footDOtes 1987-88. Iach date Strata and date. Month 2 1 o o Hov 1 27 2,8,9,10,11, 4 3 10 12,15,29,30, :n .r Other GMt] Grand total r 4 o o 21 18,24,25 3 28,.!! 2 16,17,18, 19,22,23, 26 7 3,13,20,21 6 o 2,4,8,11,12, 13,14,26 8 18 1 25 1 o 10 Feb 17,18,24 3 4,5,8,11,12, 13,15,16,29 9 10,23 2 o o o 14 Mar 2 1 3,4,8,11,14, 23,29,30 8 24,25,31 3 o o o 12 Aprc 4,6,7,11,12, 28,29 7 5,13,26,15, 16 - 17,18,19, ! ! 23 1 86 rota1 11 ~capture and recollared b Capture and kill .2 4 41 20 21,22,23 27 13 112 on 12-11, 12-87. .heep killer 129 on 1-18 and iudvertent treeing of $52 on 1-25 and 11-29. cRecapture and assist in obtaining ti.sue, blood, and se.en samples fro. 7 aature, aale, radio collared puu in cooperation with M. &oelke, D.V.M., ·Collaborative Wild Couaar Project. 147 recaptured and reco1lared on GMU 40 on 4-27-88.· rab1e 2. iate of radiocollaring GMt] 62£ 4-9-81 to 4-15-88. To No. radiocollared No. days hunted 4-29-81 2-21-82 5 -6-83 5-17~ 6-28-85 5-17-85 5- 7-87 4-15-88 1 3 7 5 7 5 14 5 16 32 91 Period 'roll 4- 9-81 12-14-81 1- 2-83 11-19-83 11-19-84 11-18-85 11-17-86 11-18-87 puaa using hounds, Uuco~re 47 III 77 136 97 70b 630b Plateau, ladio collaring rateS 16.0 10.7 13.0 22.2 11.0 27.2 6.9 !hl 13.4 aNo. day. to radio collar 1 puaaj does DOt include replacing or refitting radio collar. or puaa captured by ilethad. other than pursuit by hound. and drua ~blll&atlon. . . bDoeaDOt1nc.lude 4 day•• pent 1114dvertently pur.uing radio-collared puaa or 12 days recapturing 7 rad1o-collared .ale puaa for the ·Collaborative Wild Oouaar Project·; 4-17-88 to 4-29-88. �201 Table 3. Details on the capture and body measurements Plateau (GMU 62). of 8 puma handled during FY 1987-88, Uncompahgre Ear tattoo nuaber Sex Date of capture Est. age (80nths) Legal descr., capture site 1/4,S T R. U.T.M., capture site Elevation (m) capture site Radio collar aerial no. Transmitter freq. (MHz) Drug (Ketamine:rompun, 180: 90 mg/ml) Dosage (cc injected) Induction time (ains) Body we (kg) Measurements (em) Total body length Tail length Head-body length Chest girth Neck circumference Height of shoulder Head length Zygomatic breadth Ear length Hind foot Hind paw length Heel pad, max. dia. Left front, 1engt:h width Left rear, length width Right rear, length width ~captured bProbab1e 53 54 F F 12-19-87 48 1-11-88 14 NEB 48N llW 753-4257 1,981 6571-01 148.7285 NW27 50N 14W 724-4273 1,861 3955-01 148.0600 55 M a 56 57 47 F F M F F 4-15-88 26 4-27-88 24 1-18-88 27 12-12-87 117 NE23 SON 13W 736-4274 1,920 3956-01 148.0700 SW24 103W 135 685-4309 2,316 3964-01 148.1500 SW34 50N 11W 753-4271 1,800 SE3S 15 13 734-4286 1,768 12903-01 149.9000 2-5-88 30 .3-3-88 14 NW2 49N 13W 736-4269 2,073 12902-01 149.8890 SE36 51N 14W 728-4280 1,859 3966-01 148.1810 12 3.0 4.0 3.0 5.0 shot 49.0 3.8 60.0 36.3 61.7 35.4 45.4 51.8 38.0 4.0 4.0 42.7 211 81 130 76 42 74 18.7 13.5 9.2 27.3 9.5 204 80 124 71 38 70 19.8 13.0 8.1 26.0 8.5 212 77 135 81 49 76 23.3 15.6 8.3 28.3 10.1 195 66 129 63 36 67 20.1 12.5 7.7 26.0 9.7 214 77 137 81 40 75 20.6 14.6 8.8 28.6 9.2 207 72 135 75 41 71 21.9 15.1 9.0 26.9 190 79 111 66 39 64 20.2 14.0 8.4 26.0 7.5 195 73 123 73 38 69 20.2 14.6 7.8 27.9 9.5 4.9 5.7 4.1 5.7 4.8 5.9 4.2 5.2 4.6 6.5 4.8 5.7 4.3 5.8 4.9 3.8 4.8 6.5 4.2 5.8 4.5 and radio collar replaced in conjunction with ~Co1laborative 4.2 6.2 4.1 5.2 4.5b 6.0 8.6d 6.3 9.2 5.7 3.5 5.2 3.3 4.0 d Wild Cougar Project.~ healed fracture of left tibia. cRight front paw missing. Ear-tattooed only at 5.9 kg body weight after release from 1egho1d trap on 12-17-85. Animal pursued with bounds and shot at site of sheep killing. ~ght foot, left foot injured. �202 Table 4. Number of aerial telemetric locations of 26 puma radio tracked 7-19-87 to 7-14-88; 22 were being tracked at end of the fiscal year. Ear tatoo no. 4 5 6 7 12 20 21 22 32 34 36 37 38 40 42 44 45 46 47 50 52 53 54 55 56 57 Total Capture date 1-21-82 2- 7-83 2-10-83 3- 4-83 3-25-83 11-26-84 12- 7-84 1- 5-85 1- 8-86 2-13-86 2-13-86 12- 9-86 12-12-86 1- 3-87 1-10-87 1-17-87 1-20-87 1-22-87 1-29-87 2-17-87 4-30-87 12-19-87 1-11-88 2- 5-88 3- 3-88 4-15-88 Sex F M F F F M F M F F F F Est. age (months) on 6-8aa 101 125 94 111 124 44 53 56 53 27 M M M M F F M M M F F M F F 50 30 54 48 26 43 54 19 34 17 28 GMU 10cations No. locations 1987-88 31 51 50 49 51 45 51 49 51 51 7 48 1 50 8 47 48 4 36 27 51 30 27 20 16 13 ---------Majority Minor 62 62 62 62 62 62 62 65 62 62 65 62 62 62 25 62 62 62 40 62 62 62 411 62 62 62 62,64 40,61 62,UtahC 62 912 ---------------------------------------------------------------------------aDash indicates mortality during fiscal year except for #37 who died 7-3-88. bDistribution of aerial telemetric locations, 2-18-18 - 7-12-88; 3 in Eagle and 5 in Garfield counties. Reported by Wildlife Biologist Gene Byrne. cAll Utah locations in Little Dolores drainage. �203 Table 5. 7-14-88. Twenty-five puma captured on the Uncompahgre Capture No. Fate 4 5 Body wt. Est. age Capture method" (kg) (months)b Hounds 1-21-82 4-14-84 11-17-86 42.5 24 51 82 x 2- 7-83 5-17-85 s- 9-87 4-20-88 64.0 68.1 61 85 109 121 X X X X 34.0 12 42 X X 48 74 97 X X X X X X Sex F date M 6 F 2-10-83 8-24-85 7 F 3- 4-83 5-14-85 4-25-87 12 F Plateau (GMU 62) who were alive or fate unknown as of 46.0 3-25-83 4-30-85 12-12-87 44.0 42.7 60 85 117 Trapped Comments 9 males. 16 females listed herein X X 20 M 11-26-84 1-12-87 4-25-87 44.5 62.7 57.7 10 36 51 X X X 21 F 12- 7-84 5-12-87 36.8 49.9 12 41 X X M 1- 5-85 1- 7-87 4-22-88 56.0 69.8 69.7 15 39 54 X X X Too exhausted and hot to weigh Possibly pregnant Too exhausted and hot to weigh Capture site too steep to weigh Missing 2 1/2 toes. left front paw 25 Unk F 1-24-85 14.0 4 X Not radio collared. too small 30 Unk F 12-17-85 5- 3-86 6.4 21.8 2 6 X X Not radio collared. too small Not radio collared. too small Possibly lactating 32 F 1- 8-86 40.0 30 x 34 F 2-12-86 28.1 7 x 40 M 1- 3-87 4-22-88 70.8 70.3 32 47 X X 42 M 1-10-87 49.8 12 X 44 M 1-17-87 59.9 36 X 45 F 1-20-87 46.3 30 X M 1-29-87 4-27-88 39.0 51.8a 9 24 X X Since 1-21-88 in GMU 25 X Severe trap injury. left leg Severe trap injury, left leg 48 Unk F 2- 4-87 17.2 5 X Litter made of 49, not radio collared 49 Unk F 2- 4-87 19.5 5 X Not radio collared 52 M 4-30-87 56.3 30 X 53 F 12-19-87 49.0 48 X 54 F 1-11-88 36.3 14 X 55 M 2- 5-88 4-26-88 62.6 54.9 30 32 X X 56 F 3- 3-88 35.4 14 X F 4-15-88 45.4 26 X 57 a'22 recaptured and recollared Possibly pregnant in GMU 65 and #47 in GMU 40. bGross approximations based on dental characteristics measurements (Anderson 1983) at time(s) of capture(s). cPursuit with hounds and drug immobilization commercial trappers. (Ashman et al. 1983) and body wt. and or caught in leghold traps set for bobcat or coyotes by �204 Table 6. Thirty-two puma captured on the Uncompahgre ausl2ected as of 7-14-88. Ear Body vt. tattoo Sex Date 1 2 3 8 10 13 F F F M M M 33.1 43.5 38.5 25.9 26.3 36.3 52.0 14 15 16 17 18 19 23 24 M F M M M F M M 4-16-81 1- 5-82 1- 8-82 2-20-83 3-23-83 4-13-83 10-11-83 12-12-83 12-15-83 1-15-84 4-14-84 4-16-84 7-18-84 1- 9-85 1-23-85 26 M 3-20-85 27 28 None 29 31 33 35 36 37 38 39 None 41 43 F 46 50 51 F M no. Plateau (GMU 62) whose deatha were confirmed or P P F P P M P P M M M M F M (~) Body Eat. age Cal2ture methodb (IIOnths)a Hounds vt. Tral2l2ed (kS) 12 40 26 6 6 10 16 84 60 30 8 36 7 12 18 X X X X X X X X X X X X 44.0 10 X 4-24-85 11-20-85 12-14-85 12-17-85 12-30-85 2- 4-86 2-13-86 2-13-86 12- 9-86 12-12-86 12-19-86 4- 3-86 1- 8-87 1-16-87 36.3 43.1 14.5 5.9 12.9 23.6 30.9 25.4 27.8 X X X 32.2 33.1 53.5 39.9 14 24 3 2 4 6 6 6 6 36 7 8 14 24 X X X X X X X X 61.3 33.1 53.5 39.9 1-22-87 2-17-87 3-16-87 46.3 51.8 29.1 60 13 7 X X X 29.1 48.0 55.0 36.2 64.3 28.0 44.0 32.2 X X X X X X aGross approximations based on dental charscteristics measurements (Anderson 1983b) at time of capture. bpursuit with hounds and drug immobilization coyotes by commercial trappers. 14.5 38.0 40.0 Date Cause(s) Unconfirmed 1-10-82 Illegal kill Unconfirmed 8- 4-83 Capture trauma 5-29-8JC UnkDovn Unconfir.ed Area GMU 62 GMU 62 GMU 62 6-l6-8JC Possible predacide GMU 62 3-26-86c Prob. capture trauma GMU 62 c GMU 62 3-27-84 Puma GMU 42 1-11-85 Legal kill GMU 65 3-18-86 Legal kill Sbot as aheep killer GMU 70 1-15-86 Legal kill GMU 40 12-12-85 GMU 62 Prob. capture 1-23-85 trauma - puma attack injuries 2-18-87 Legal kill w. of Ibnticello, Utah 12- 9-85 Legal kill GMU 61 11-22-86 Legal kill GMU 40 12-14-85 Hounds GMU 62 1-18-88 Sbot as sheep killer GMU 62 1- 7-86 Trsp injuries GMU 62 11-6-86 Illegal kill GMU 65 Unknovn Unknovn GMU 40 8- 7-8r Unknovn GMU 62 7- 3-88 Sbot as sheep killer GMU 62 c 5-l8-87 Unknovn GMU 62 12-22-87 Legal kill GMU 40 4- 3-86 Hounds GMU 62 1- 8-87 Fall from tree GMU 62 1-16-87 Probably captureGMU 62 related 8- i-sz'' Unknovn GMU 62 c 2-l9-87 Unknovn GMU 62 3-16-87 Hounds GMU 62 (Ashman et al. 1983) and body ¥t. and (Ho) or caught in legbold traps set for bobcst or cOate of death judged as ~ 3 days of the actual; all other dates are actual dates of death. �205 Table 7. 1981-88. Mortality among puma captured on the Uncompahgre Ages estimated at the time of death. Less than 24 months Male Female Plateau, GMU 62, 24 months and older Male Female Total Radiocollared Unconfirmed Illegal kill Legal killa Unknown causes Suspected predacide Intraspecific strife Predator managementb Capture-related o o 1 1 o 3 2 1 1 o o 2 2 1 1 o o o 1 1 o 1 3 1 1 1 2 7 6 1 1 1 2 2 6 28 o o 4 o Subtotal 9 5 7 7 Not radio collared Capture-related Predator managementb 1 2 Subtotal Total o o o o o 1 o 3 1 1 2 o 1 4 10 7 7 8 32 a3 puma killed in GMU 40, 1 in GMU 42, 1 in GMU 61, and 1 in GMU 65, and 1 west of Monticello, Utah. bpuma shot after killing domestic sheep; 2 shot in GMU 62 and 1 in GMU 70. �206 Table 8. Age and sex classes of 57 puma at first capture on the Uncompahgre Plateau, GMU 62, 1981-88. Includes all puma handled. Year 1981-82 1982-83 1983-84 1984-85 1985-86 1986-87 1987-88 Less than 24 months of a~e 24 months and older Male Male 0 3 1 5 2 6 0 Female 1 1 0 4 7 3 2 Total 17 18 --------------------------------- Female Total 0 1 3 0 0 4 1 3 2 1 0 2 3 2 4 7 5 9 11 16 5 9 13 57 Table 9. Age and sex classes of 49 puma radioco11ared at first capture, Uncompahgre Plateau, GMU 62, 1981-88. Excludes 8 puma handled but not radiocollared. Less than 24 months of age Year Male 1981-82 1982-83 1983-84 1984-85 1985-86 1986-87 1987-88 Total Female 24 months and older Male Female o 1 o 3 3 1 1 2 1 Total 4 7 1 o 5 1 3 3 o 2 6 5 o 2 2 4 3 1 2 14 5 15 12 9 13 49 3 o o 5 8 Table 10. Age and sex classes of 21 puma alive and being radio tracked as of 7-14-88. Includes 1 male (#42) radio tracked by Wildlife Biologist G. Byrne in GMU 25. Less than 24 months of age Year 1987-88 Male o Female 2 24 months and older Male 9 Female 10 Total 21 �207 Table 11. Some vital statistics of 21 male and 23 female puma captured on the VncomEahgre Plateau (GMU ~2), 1981-88. Datesa Ear Est. age tattoo no. (months) Capture Death 61 6 6 9 84 30 7 36 10 15 12 10 36 7 32 12 36 9 13 30 30 2- 7-83 2-20-83 3-23-83 4-13-83 12-12-83 1-15-84 4-14-84 4-16-84 11-26-84 1- 5-85 1- 9-85 3-20-85 12-12-86 12-19-86 1- 3-87 1-10-87 1-17-87 1-29-87 2-17-87 4-30-87 2- 5-88 A 8- 4-83 5-29-83 Uc 6-16-84 3-28-84 1-11-85 3-18-86 A A 12-12-85 2-18-87 5-18-87 12-22-87 A A A A 2-18-88 A A Dal:s monitored MALE 5 8 lOb 13 14b 16b 17 18 20 22 23 26 38b 39 40 42 44 47 50 52 55 1,983 165 66 186 72 262 701 1,326 1,292 335 699 157 368 558 549 538 526 366 441 160 FEMALE 1 12 4-16-81 U 1-10-82 1- 5-82 2 40 3 26 U 1- 8-82 A 1-21-82 4 24 6 12 2-10-83 A 3- 4-83 A 48 7 12 A 61 3-25-83 15b 12-15-83 3-23-86 60 1-15-85 7-18-84 19 7 21 12 A 12- 7-84 12- 9-85 4-24-85 27 14 28 24 11-20-85 11-22-86 1-18-88 12-17-85 29 2 32 30 1- 8-86 A 11- 6-86 2- 4-86 7 33 34 6 2-12-86 A 36b 2-13-86 8- 7-87 6 7- 3-88 12- 9-86 37 6 45 A 30 1-20-87 A 12-19-87 48 53 54 A 14 1-11-88 A 3- 3-88 56 14 57 26 A 4-15-88 --------------------------------------------------a"A" indicates puma alive at last telemetric signal during July, bPuma whose date of death approximated i3 5 2,371 1,980 1,957 1,936 1,193 181 1,315 229 367 762 918 275 883 540 572 541 208 155 127 91 1988. days from the actual date. c"U" indicates death of puma was unconfirmed; numbers, 1, 3, 13. d Dates of death for pumas #35 and #46 are unknown. �208 Table 12. Temporal factors in radio tracking puma captured on Uncompahgre Plateau (GMU 62), 1981-88. Statistic Sex and variable SD Min. Max. 24.1 537.5 20.4 487.0 6 66 84 1,983 11 307.0a 221.2 66 701 21 21 23.4 790.8 18.4 729.5 2 5 61 2,371 458.2a 358.6 5 1,193 N X 20 20 MALE Est. age (months) No. days monitored No. days from capture to death FEMALE Est. age (months) No. days monitored No. days from capture to death 9 ------------------------------------------------------------------------------aMeans did not differ (p < 0.05) from each other. Table 13. Number of resident puma on Uncompahgre Plateau related to days monitored as of 7-14-88. Male 365 730 731 - 1,096 1,097 - 1,462 4 0 2a 2 1 2 6 1 4 1 - 4 5 7 9 ----- 1,463+ ---------------------aApproximate1y nonresident. Female Total Days monitored 1,000 days monitored as a resident, 200-300 days as a 16 �209 Table 14. Eisht .ule deer killed bl ~umal Unco.E!hgre Plateau Date (GMU62)1 1987-88. Lesal deecri2tion Eat. ase (.os. ) 1/4 Habitat Co_nU piDe~alt red on by 2 pu.a, DDt covered Part1ally covered Covered, ld11ed by pu.a found Sex 11-28-87a F 16 SE 16 46N 9W 12-12-87 3- 3-88· F F aature aature SE SW 35 36 15S 5lN 98W 14W 4- .5-88 4- 8-88 4-18-88 4-25-88 F SE NW SW SW 11 19 22 21 49N l3W 48N 11W 47N 8W 49N 11W P-J P-J P-J P-J, 4-26-88 F SE 18 49 P-J S I. T P-J, .parae P-J, roadside # 156 aSee 10 10 10 F H 12W Not covered Only hair aDd drag aarlt found Covered ria text. Table 15. Age claaaee (GMU62) 1981-88.a and aell: 0 f cervids 13-17 .os ~12 .os Fiscal lear SE!!e1es Unco-.pah&re Plateau 1t1l1ed by p~, 18+ .oa H F H F H F Sex unit Age unit Sell: and ale unit Total 1980-81 .ue ellt deer 0 0 1 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 3 0 1981-82 .w.e deer elk 1 0 0 0 0 0 0 0 2 0 6 0 0 0 0 0 0 0 9 0 1982-83 .w.e deer ellt 0 0 1 0 1 0 2 0 0 0 5 0 0 0 0 0 0 0 9 0 -1983-84 lIUle deer ellt 3 0 4 0 0 0 1 1 0 0 2 1 1 0 1 0 0 0 12 2 1984-85 .w.e deer ellt 1 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 4 0 7 0 1985-86 .w.e deer ellt 0 0 1 0 0 0 1 0 1 0 2 0 4 1 0 0 0 0 9 1 1986-87 .w.e deer aU 0 0 0 1 0 0 0 0 0 0 3 0 6 0 0 0 2 0 11 1 1987-88 .w.e deer alit 0 0 2 0 0 0 1 0 0 0 3 0 1 0 0 0 1 0 8 0 Total .w.e deer S 10 1 S 4 23 12 1 7 68 Total ellt 0 1 0 1 0 1 1 0 0 aThe aajority of 1t1l1a found fro. late No_her to early Hay while purau1D& paa with bounds. bOne ellt (1986-87) fro. GMU6S (Billy CIt) probably 1t1l1ed by pu.a 122. 4b �21ID o 10 20 I I I KM Figure 1. Puma study area GMU 62, Uncompahgre Plateau, showing subunits. �211 APPENDIX �212 AERIAL TELEMETRY LOCATIONS OF 26 PUMA Legal description Date 1/4 S T U.T.M. R X Y Appro~. elev (m) Distance (IuD) between locstions Rating Major drainase S1snal Location ADULT FEMALE PUMA 14 7-1H7 7-24-87 8- 5-87 8- 9-87 8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 10-16-87 10-23-87 10-29-87 11- 6-87 11-13-87 11-20-87 11-28-87 12- 4-87 12-11-87 12-21-87 12-29-87 1- 8-88 1-15-88 1-22-88 1-29-88 2- 4-88 2-12-88 2-19-88 2-26-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-16-88 4-22-88 4-29-88 5- 7-88 5-20-88 5-27-88 6- 4-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 8-88 7-14-88 7-20-88 ININ IN SW SW HE SE HE IN IN IN SW IN SE HE IN HE SE IN SW SE HE SE HE SW IN SW IN SW HE SW No No No No No No No No IN No No No No No No No No No No No -- 9 47 13 47 29 47 47 13 34 48 33 48 7 47 33 48 8 47 33 48 33 48 8 47 17 47 32 48 8 47 7 47 18 47 17 47 47 8 4 47 4 47 22 48 32 48 48 21 32 48 28 48 23 47 28 48 47 8 - 33 48 34 48 location location location location location location location signal 14 50 location location signal location signal location location location location location location - 10 239 4248 2,286 1.0 Spring G G 758 4246 11 2,499 4.9 Spring G G 4242 10 762 2,408 4.7 E Fk Spring G G 4245 11 758 2,621 4.0 Spring G F 10 241 4250 2,073 8.2 G G Spring 10 240 4251 2,134 0.9 Spring G F 10 761 4247 2,377 4.8 Spring G F 10 240 4251 2,134 -G 4.9 G Spring 10 762 4247 2,347 4.3 G G Spring 10 240 4251 2,164 4.3 Spring G G 10 4251 239 2,196 G 0.7 Devinny G 10 762 4247 2,377 4.4 G Spring G 10 762 4246 2,316 1.5 G G Spring 10 762 4250 2,256 4.2 G Devinny G 10 4248 762 2,316 G 2.1 Spring G 10 761 4247 2,377 2.0 G Spring G 10 761 4246 2,438 1.4 G Spring G 10 239 4245 2,438 2.2 G Spring G 10 762 4247 2,286 2.6 G Spring G 10 239 4248 2,134 1.4 Spring G G 10 4248 240 2,256 1.0 G G Spring 4254 10 242 1,890 6.4 G Spring G 10 762 4250 2,286 5.6 Spring G G 10 240 4254 4.7 2,012 Lindsay G G 762 4251 10 2,256 4.5 Devinny G G 4252 10 239 2,103 2.7 Lindsay F G 243 4244 10 2,316 9.4 Happy G F 4252 239 1,829 9.5 10 Lindsay G F 761 4247 10 2,377 5.8 Spring G G 4250 10 240 2,073 4.5 Spring G G 4250 10 241 2,164 0.9 Spring G G Fair momentary signal over Potter and Criswell Drainages Faint momentsry signals from Upper Little Dominguez to Spring Ck Fsint momentary signal Escalante to Spring Ck Good intermittent signal over southcentral Dry Mesa Good intermittent signal over IN portion Dry Mesa Mostly poor signals IN Jct Big Dom-Guonison R, Sawmill Mesa, Monitor and 7 N Mesa No signals over same route as 4-15-88 4775 Roubideau 12 745 G Strong signal over Granite Can (GMU 40) and a less strong signal over Dry Mesa Signals of varying quality from Montrose north to Big Dominguez Signals good quality, momentary, P just HE Blake Field, Delta Signals of varying quality from Dry Ck Basin to Upper Escalante Poor signals in Horsefly Ck vicinity Good momentary signal heard over Ladder Can, GMU 40 Fair signal over Spring Ck Basin Fair momentary signal IN of Delta; rim Grand Mesa Fair momentary signal Log Hill Mesa ADULT MALE PUMA 85 7-19-87 7-24-87 8- 5-87 8- 9-87 8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 10-16-87 10-23-87 10-29-87 11- 6-87 11-13-87 11-20-87 11-28-87 12- 4-87 12-11-87 12-21-87 12-29-87 1-10-88 1-15-88 1-22-88 1-29-88 2- 5-88 IN NW HE HE HE SW SW IN IN SE IN SW SW IN IN SW SE IN SE HE HE HE HE HE HE SE SW HE 25 10 9 8 6 4 21 17 29 36 27 29 26 1 30 31 31 23 8 31 8 9 35 7 10 1 33 33 49 49 48 49 48 49 49 49 49 50 50 49 49 49 50 50 50 50 48 49 49 49 49 49 49 49 49 49 13 13 13 12 12 13 13 12 12 14 13 12 13 13 12 13 12 13 12 12 12 13 13 11 12 12 11 11 738 734 735 741 741 732 732 740 740 728 734 741 736 738 738 739 739 736 743 739 741 733 737 749 744 748 752 753 4262 4267 4257 4267 4260 4268 4263 4206 4263 4269 4272 4262 4261 4269 4272 4270 4270 4274 4256 4261 4268 4267 4261 4268 4268 4269 4260 4261 2,316 2,256 2,682 2,042 2,347 2,377 2,408 ~,O42 2,377 2,103 2,225 2,256 2,499 2,256 2,042 2,134 2,103 2,073 2,499 2,408 1,981 2,316 2,438 1,981 1,951 1,951 2,103 2,134 1.9 6.3 10.7 12.2 7.9 8.9 5.0 8.3 3.2 13.2 5.9 13.5 5.0 7.4 3.5 2.3 0.3 5.3 19.2 6.2 7.1 8.7 7.3 14.7 5.3 3.6 9.0 1.1 Criswell Little Monitor Criswell Criswell Traver Cottonwood Monitor Criswell Traver Dry Fk Escalante Cottonwood Traver Criswell Monitor Monitor Potter Potter Cottonwood Bull Traver Criswell Cottonwood Criswell Big Sandy Wash Roub1deau Roatcap Gulch Piney Piney G G G G G G G G G G G G G G G G G G G G G G G G G G G G G F F F F F F G G F G F G G F G G G G G G G G F G F G G �213 Legal description Date 1/4 S T R U.T.H. X Y Approx. dev (m) Distance (km) between locations Rating Major drainase Sisna1 Location Adult Male Puma IS - continued 2-12-88 2-19-88 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 4-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 8-88 7-14-88 SE SW NW SW SE SE SE SE SW NW SW SE SE SW SE NE SE SW SW SW SE SW NE 1 1 12 24 18 15 16 21 36 7 1 10 9 11 31 16 15 27 24 34 23 20 12 48 48 48 48 48 49 49 49 50 48 48 48 48 49 49 48 49 49 49 49 49 49 48 11 11 11 11 10 11 11 11 12 11 12 12 12 13 12 13 13 13 13 13 13 12 13 759 759 758 759 761 754 753 752 747 750 749 747 744 737 739 735 735 734 738 734 738 741 740 4259 4258 4257 4253 4255 4266 4265 4264 4270 4257 4259 4256 4256 4266 4260 4255 4264 4262 4263 4260 4263 4263 4257 1,951 2,012 2,073 2,256 2,103 1,951 1,981 1,981 2,012 2,316 2,286 2,377 2,469 2,225 2,408 2,775 2,347 2,408 2,347 2,621 2,377 2,256 2,591 6.6 0.8 0.7 4.3 2.8 13.0 1.1 1.6 8.1 13.3 2.3 2.8 2.2 13.2 7.0 7.0 9.9 3.3 3.8 4.4 4.4 4.0 6.3 Coal Coal Coal Spring Coal Cushman Cushman Cushman Roatcap Piney Cushman Roubideau Roubideau Monitor Traver Moore Potter Potter Criswell Potter Criswell Roubideau Wright G G G G G G G G G G G G G G G G G G G G G G G G G G Criswell Moore Criswell Criswell Criswell Moore Criswell Criswell Potter Criswell Criswell Roubideau Terrible Traver Moore Traver Traver Criswell Criswell Criswell Moore Criswell Traver Potter Potter Criswell Potter Potter Criswell Criswell Potter Potter Potter Potter Potter Potter Potter Criswell Traver Traver Bull Criswell Criswell Terrible Wright Terrible Criswell Roubideau Roubideau Roubideau G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G F F G F F F F G G F G G G G F G F G G G F ADULT FEMALE PUMA #6 7-19-87 7-24-87 8- 5-87 8- 9-87 8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 10-16-87 10-23-87 10-29-87 11- 6-87 11-13-87 11-20-87 11-28-87 12- 4-87 12-11-87 12-21-87 12-29-87 1- 8-88 1-15-88 1-22-88 1-29-88 2- 5-88 2-12-88 2-19-88 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 3-88 6-17-88 6-23-88 6-30-88 7- 8-88 7-14-88 SW NW NW SW SE HE SW NW SE SW SE NW SW NW SE SE SE SW SE SW SW SW SW NW SW SW SW SE SW NE NE NW HE SE SW NW NW NW NW SE HE SW SE NW NW NW HE HE NW NW 25 30 25 24 35 36 25 36 22 25 18 27 6 32 19 29 30 19 35 19 30 30 29 14 12 13 32 1 27 33 28 16 31 31 7 14 5 9 31 2 17 30 4 7 6 7 35 9 16 15 49 49 49 49 49 49 49 49 49 49 49 49 48 49 49 49 49 49 49 49 49 49 49 49 49 49 50 49 50 50 50 50 50 50 49 49 49 49 49 48 48 49 48 48 48 48 49 48 48 48 13 12 13 13 13 13 13 13 13 13 12 12 12 12 12 12 12 12 13 12 12 12 12 13 13 13 12 13 12 12 12 12 12 12 12 13 12 12 12 13 12 12 13 12 12 12 13 12 12 12 738 739 738 738 737 738 738 738 734 738 740 ·744 741 740 741 741 740 739 738 739 740 739 740 736 739 739 741 738 743 742 743 742 739 739 739 735 741 742 739 738 743 739 735 741 741 740 737 746 744 745 4262 4262 4263 4264 4260 4261 4262 4261 4263 4261 4265 4263 4258 4261 4263 4262 4267 4263 4260 4263 4261 4262 4262 4266 4266 4265 4270 4268 4272 4271 4272 4276 4270 4270 4267 4266 4269 4268 4261 4258 4255 4262 4258 4257 4259 4257 4261 4257 4255 4255 2,347 2,347 2,377 2,377 2,469 2,499 2,408 2,438 2,377 2.377 2,073 1.951 2.469 2,316 2.286 2.256 2.438 2.256 2.469 2.256 2.347 2,347 2.408 2.286 2.134 2.256 2.042 2.256 1.981 2.103 2,042 2.012 2,103 2.134 2,225 2,316 2.164 2.103 2,438 2,560 2,499 2,347 2,012 2,469 2,408 2,560 2,469 2,347 2,530 2,134 1.2 2.1 1.4 1.3 3.3 1.6 1.6 0.6 3.5 3.5 4.1 4.7 4.8 2.4 2.3 1.8 1.2 1.8 3.9 3.6 1.8 0.5 1.7 6.1 1.9 1.7 6.0 3.9 6.6 1.1 1.3 3.5 5.5 0.7 3.1 3.9 6.3 1.8 7.3 3.2 5.3 7.6 5.7 5.2 2.0 2.5 5.4 8.8 2.5 1.4 G F F G F G G G F G F G F G G G G G G G F G F G G F G G G F F G F G F G G G G G G G F G G F F G G �214 Legal deacription Date 1/4 S T D.T.M. R X Distance Y Appro>:. elev (m) (kill) between locations Rating Major drainase Sisnal Location ADULT FEMALE PUMA 17 7-19-87 7-24-87 8- 5-87 8- 9-87 8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 10-16-87 10-23-87 10-29-87 ll- 6-87 11-13-87 11-20-87 11-28-87 12-11-87 12-21-87 12-29-87 1- 8-88 1-15-88 1-22-88 1-29-88 2- 5-88 2-12-88 2-19-88 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 3-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 8-88 7-14-88 NW NW SE SW NW NW SE HE NW HE HE NW SW SE HE SW NW HE SE SW SW SW SE SE HE NW HE SE HE HE HE HE NW SE NW SE HE NW SE SW No SE NW NW NW NW NW NW NW HE 20 16 10 12 70 15 17 5 4 24 7 23 32 10 16 35 3 10 19 4 3 33 14 32 21 22 27 6 . 14 6 17 4 20 19 29 30 34 25 13 35 signal 36 17 34 36 23 7 11 6 6 49 49 49 49 49 49 49 49 49 49 49 49 50 49 49 50 49 49 50 49 49 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 49 50 14 14 14 14 14 14 14 13 13 14 13 14 13 14 14 14 14 14 13 13 14 13 13 13 13 13 13 12 13 12 13 13 13 13 13 13 14 14 14 14 721 723 725 727 725 724 722 731 732 729 730 726 731 725 724 726 724 725 730 732 724 732 736 732 732 733 734 739 736 739 732 733 730 730 730 730 725 ·727 729 726 4264 4265 4266 4266 4267 4265 4264 4269 4268 4264 4267 4264 4269 4266 4265 4269 4269 4267 4273 4268 4268 4270 4275 4269 4274 4274 4272 4278 4275 4279 4275 4279 4274 4273 4272 4271 4270 4272 4265 4269 2,499 2,256 2,438 2,316 2,377 2,469 2,316 2,316 2,256 2,499 2,408 2,499 2,377 2,560 2,438 2,196 2,377 2,408 2,164 2,103 2,316 2,347 2,073 2,316 2,134 2,225 2,073 1,951 2,073 1,859 2,073 1,981 2,164 2,196 2,225 2,225 2,225 2,377 2,499 2,103 6.2 2.1 2.8 2.0 2.5 2.7 2.1 8.0 0.6 6.3 4.0 5.0 8.0 2.6 1.6 4.6 1.9 1.6 8.0 5.2 8.0 8.5 6.9 7.3 4.3 1.2 1.7 7.2 4.0 5.2 8.5 3.7 5.7 0.6 1.4 0.5 5.8 3.3 7.0 5.0 E Fk Escalante E Fk Escalante E Fk Escalante Dry Fk Escalante Middle Pk Escalante E Pk Escalante E Fk Escalante Cottonwood Cottonwood Cottonwood Cottonwood Dry Fk Escalante Cottonwood E Pk Escalante E Fk Eacalante E Pk Eaca1ante E Pk Eacalante E Fk Escalante Dry Fk Escalante Cottonwood E Fk Escalante Cottonwood Cottonwood Cottonwood Dry Fk Escalante Grade G Cottonwood Cottonwood Cottonwood Cottonwood Dry Fk Escalante Dry Fk Escalante Dry Fk Escalante Dry Fk Escalante Dry Fk Escalante Dry Fk Escalante E Fk Escalante E Fk Escalante Cottonwood E Fk Escalante G G G G 50 49 50 50 49 49 49 49 49 14 13 14 14 14 13 14 13 13 728 729 724 727 726 729 726 729 730 4269 4265 4271 4270 4264 4267 4267 4269 4269 2,103 2,469 2,347 2,377 2,499 2,438 2,499 2,408 2,408 3.1 4.2 6.5 2.7 6.3 4.6 3.5 4.0 0.5 Dry Fk Escalante Cottonwood Middle Fk Escalante E Fk Escalante Dry Fk Escalante Dry Fk Escalante E Fk Escalante Dry Fk Escalante Dry Fk Escalante G G G G KiddIe Middle Kelso Middle KiddIe Middle Middle G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G F F P F G F .F G G F G G G F G G G G G G P G P G G P F G G F F F P F P F G G F G P G F G G F G F G ADULT FEMALE PUMA #12 7-19-87 7-24-87 8- 5-87 8- 9-87 8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 10-16-87 10-23-87 10-29-87 11- 6-87 11-13-87 11-20-87 11-28-87 12- 4-87 12-11-87 12-21-87 12-29-87 1- 8-88 1-15-88 1-22-88 1-29-88 SW SE NW SW NW HE SW SE SE SW SW HE HE NW SW HE SW SE SE SE SE SW SE SE HE SE NE 30 29 19 30 31 79 30 36 31 36 17 19 29 13 10 25 22 1 26 12 35 22 6 33 1 29 4 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 51 50 15 51 50 51 50 51 50 14 14 14 14 ·14 14 14 15 14 15 14 14 14 14 14 15 14 14 14 14 13 13 13 13 14 13 13 719 722 719 719 719 722 719 718 720 118 720 720 721 727 724 118 724 728 726 728 734 734 729 733 728 131 133 4271 4271 4273 4270 4270 4271 4271 4269 4270 4269 4274 4273 4271 4275 4275 4271 4273 4278 4281 4276 4286 4283 4278 4280 4278 4281 4279 2,560 2,103 2,134 2,499 2,469 2,377 2,560 2,316 2,256 2,347 2,225 2,134 2,377 2,256 2,256 2,560 2,196 2,164 2,134 2,286 1,768 1,951 2,196 2,042 2,134 1,981 1,951 2.4 2.6 4.5 2.7 0.4 3.2 3.0 1.7 2.0 2.2 5.3 0.8 2.2 6.8 3.0 7.3 6.1 2.2 4.3 5.3 12.0 3.6 6.6 4.2 4.8 3.7 2.8 ~.!::!;!ls Fk Escalante Fk Escalante Fk Fk Fk Fk Escalante Escalante Escalante Escalante rll Escalante Middle Fk Escalante KiddIe Fk Escalante Kelso Kelso Middle Fk Escalante Escalante Kelso Kelso KiddIe Fk Escalante Escalante Escalante Escalante Escalante Escalante Tatum D Dry Fk Escalante Escalante Escalante Dry Fk Escalante G G G G G G G G G G G G G F G F F G F G G G F F G F G G G F G G G G G G G G G G G G F G G G G G F G �215 Legal description Date 1/4 S T U.l.M. R X Y Approx. dev (m) Distance (km) between locations Rating Major drainalle Sillnal Location Adult female 2um8 112 - continued 2- 5-88 2-12-88 2-19-88 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 4-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 8-88 7-14-88 NW NE NE SE HE NW NW NW SE SW NW NW NW h'W NW SE SW HE HE SE SW SE SW NW 4 28 10 28 14 4 34 15 29 10 20 30 15 33 2 3 28 29 6 18 14 10 34 21 SO 51 SO 51 SO 50 51 50 51 50 50 50 50 50 49 49 SO SO 49 SO 50 50 SO 50 13 13 14 13 14 13 13 13 13 14 14 14 14 15 15 15 15 15 15 14 14 14 15 14 732 732 724 733 727 732 734 733 731 724 721 719 724 713 716 715 713 713 712 720 725 725 715 722 4278 4282 4276 4281 4275 4279 4280 4275 4281 4276 4273 4271 4275 4278 4268 4268 4271 4271 4268 4274 4274 4276 4269 4273 2,164 2,073 1,981 2,073 2,225 2,042 2,042 2,073 1,981 2,164 2,256 2,499 2,286 2,714 2,347 2,377 2,408 2,408 2,560 2,256 2,134 2,134 2,621 2,377 1.2 6.9 9.2 9.5 9.0 7.0 2.2 4.7 6.7 8.8 4.0 2.5 5.8 11.7 3.2 0.7 4.4 0.4 3.2 10.9 5.2 1.8 12.2 8.7 Dry Fk Escalante Eecalante Kelso Tatwa D Escalante Dry Fk Escalante Dry Fk Escalante Dry Fk Escalante Eecalante Kelso Ke1ao Kdso Eac:alante Kdso Middle Fk Escalante Middle Fk Escalante Ke1ao Kelso Ke1ao Kelso E Fk Escalante Escalante Middle Fk Escalante Kelso G G G G G G G G G G G G G G G G G G G G G G G G 1,829 2,316 2,316 2,256 2,377 2,377 1,951 2,042 2,073 1,981 2,286 1,981 2,042 2,469 2,408 2,347 2,196 1,890 2,073 1,981 2,042 2,286 2,134 1,920 2,073 1,981 1,981 1,920 1,920 1,981 6.1 18.1 1.0 5.8 1.6 7.7 15.4 6.7 8.3 3.3 3.5 13.1 12.8 3.5 0.8 6.2 13.7 15.2 12.7 11.6 7.9 21.1 18.0 13.6 16.5 0.9 0.2 17.1 12.5 3.6 Criswell 'IIFk Dry 'IIFk Dry Coa1bank Roubideau 'IIFk Dry Roubideau Criswell Roubideau Roubideau Roubideau Roubideau Roubideau Roubideau Roubideau 'IIFk Dry Moore Dry Ck Roubideau 'IIFk Dry Roubideau Spring Piney Roubideau E Fk Dry Dry Ck E Fk Dry Roubideau Dry Dry G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G 1,859 2,134 2,012 2,103 2,103 1,981 2,286 2,316 2,286 2,073 2,164 2,286 2,377 2,408 2,408 5.4 7.7 28.0 3.4 7.4 6.8 5.3 4.3 2.8 4.4 5.2 9.5 12.3 2.8 6.5 Cushman 'IIFk Dry Ck Roubideau Roubideau Coa1bank Roubideau Roubideau Big Sandy IJash Roubideau Roubideau Roubideau E Fk Dry Ck Long Roubideau Traver G G G G G G G G G G G G G G G Dry Fk Escalante E Fk Escalante Cottonwood Escalante C F G G G G G G G G F G G F F F G G F F G G G F G F F F F G MALE PUMA #20 7-19-87 8- 5-87 8- 9-87 8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 10-16-87 10-23-87 10-29-87 11-13-87 11-28-87 12- 4-87 12-11-87 12-21-87 12-29-87 1- 8-88 1-15-88 1-22-88 2-12-88 2-19-88 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 3-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 8-88 7-14-88 34 NW 50 12 48 NW 19 11 SE 48 11 18 48 NW 2 12 SE 49 3 12 48 11 NW 17 49 NW 2 12 HE 49 18 12 HE 4 48 12 SE 49 28 12 NW 3 48 12 HE 26 50 12 HE 4 48 12 48 SE 9 12 48 HE 9 12 SE 48 18 11 SW 49 17 12 11 NW 48 3 49 12 SW 28 48 HE 8 11 48 12 SW 3 47 10 NE 17 49 SW 33 11 SW 34 50 12 48 11 HE 9 SE 4 48 11 48 11 SE 4 SW 26 50 12 NW 49 11 23 11 49 SW 35 No signal - Extensive NW 15 48 11 48 SE 5 11 49 12 HE 9 NW 21 49 ::.2 SE 49 11 19 49 SE 28 12 48 SE 12 3 49 12 SW 26 48 12 NW 3 49 12 HE 28 48 12 SW 3 48 11 SW 21 48 12 NW 8 48 12 HE 9 49 13 SE 31 743 4271 750 4254 751 4255 747 4259 745 4260 752 4256 745 4269 741 4265 745 4259 743 4262 746 4259 746 4272 745 4260 744 4256 745 4257 751 4256 741 4265 755 4259 742 4262 753 4257 745 4258 4246 238 752 4260 744 4270 4257 755 755 4259 4258 755 745 4272 754 4264 755 4261 search 4266 753 753 4258 742 4268 4264 7;';' 749 4264 743 4262 746 4258 745 4261 746 4259 743 4262 745 4258 754 4253 742 4257 745 4257 740 4260 Ck Ck Ck Ck Ck Ck Ck F F F G F F F F F F F G G G G G G F G F F G G G G G G G G F F G F G F F F F F F G G G G G ADULT FEl-1ALEPUMA 121 7-19-87 7-24-87 8- 5-87 8- 9-87 NW SW NW HE 10 3 6 22 49 49 49 50 14 14 13 14 724 124 729 725 4267 4268 4268 4273 2,286 2,347 2,408 2,196 0.7 1.5 5.0 6.5 F F �216 Legal description Date Adult 1/4 female S T U.I.M. R X y Approx. elev (m) Distance (Itm) between locations Rating Major drainal:le S11:lnal Location 2um8 121 - continued 8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 10-16-87 10-23-87 10-29-87 11-6-87 11-13-87 11-20-87 11-28-87 12- 4-87 12-11-87 12-21-87 12-29-87 1- 8-88 1-15-88 1-22-88 1-29-88 2- 5-88 2-12-88 2-19-88 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 3-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 8-88 7-14-88 29 7 7 34 HE 1 HE 33 NW 12 HE 36 NW 2 SE 9 SE 36 SE 3 SE 6 SW 27 HE 8 SW 19 NW 7 SE 1 SW 34 SE 32 HE 8 HE 16 NW 4 HE 5 ME 9 SE 16 SW 20 NW 8 NW - 3 NW 16 SE 20 SW 16 SE 24 SW 25 SW 6 SE 32 NW 5 SW 1 SE 6 NW 17 ME 34 SW 30 SE 28 SW 30 NW 21 HE 16 SE 1 50 49 49 50 49 50 49 50 49 49 50 49 50 51 7-19-87 7-24-87 8- 5-87 8- 9-87 8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 10-16-87 10-23-87 10-29-87 11- 6-87 11-13-87 11-20-87 11-28-87 12- 4-87 12-11-87 12-21-87 12-29-87 1-10-88 1-15-88 1-22-88 1-29-88 2- 5-88 2-12-88 2-19-88 SE 46 46 48 48 48 46 48 50 48 48 48 49 48 50 50 50 47 50 47 48 50 48 50 46 48 50 50 50 49 50 ME SW SE SE SO SO 50 50 51 51 50 50 50 50 50 50 50 50 50 50 SO 50 50 50 50 51 49 49 49 49 50 50 50 50 49 49 49 14 14 14 15 15 14 15 15 15 15 15 15 13 13 13 13 13 14 13 13 13 13 13 13 13 13 13 13 13 13 13 13 14 14 13 13 14 15 14 14 14 14 14 14 15 15 15 722 719 720 715 719 724 718 718 716 715 718 715 729 734 731 729 729 728 733 731 731 733 732 731 733 733 732 730 734 732 731 732 728 727 729 731 721 718 720 721 725 719 723 719 716 714 719 4272 4266 4266 4269 4269 4270 4266 4270 4268 4268 4269 4267 4277 4281 4277 4272 4277 4277 4280 4279 4277 4275 4279 4278 4277 4274 4274 4277 4278 4275 4273 4274 4272 4271 4278 4279 4269 4267 4267 4265 4270 4271 4271 4271 4268 4265 4267 259 258 263 261 261 257 260 258 261 261 262 266 261 260 261 261 262 264 262 262 258 263 261 264 261 255 252 252 263 259 4232 4235 4252 4253 4253 4236 4254 4271 4254 4254 4254 4260 4256 4270 4276 4270 4245 4275 4243 4253 4271 4257 4270 4238 4254 4274 4274 4277 4269 4271 2,377 2,469 2,560 2,621 2,316 2,316 2,255 2,530 2,469 2,377 2,438 2,560 2,196 2,073 2,164 2,256 2,225 2,196 2,012 2,073 2,103 2,073 2,073 2,134 2,012 2,134 2,164 2,256 2,012 1,920 2,134 1,859 2,377 2,286 2,256 2,164 2,408 2,408 2,377 2,499 2,256 2,530 2,225 2,591 2,499 2,621 2,196 3.1 6.8 0.9 5.4 4.4 5.2 7.3 3.7 2.6 1.2 3.3 3.7 12.5 5.4 4.4 5.1 4.4 1.2 6.5 2.1 2.3 2.6 3.8 1.0 2.2 3.4 0.9 3.7 4.0 3.7 2.1 1.5 4.3 1.5 6.5 2.3 15.0 3.0 1.8 2.3 6.0 6.0 6.1 4.4 4.2 3.8 5.4 Middle Fk Escalante Middle Fir.Escalante Middle Fk Escalante Middle Fk Escalante Middle Fk Escalante Middle Fir.Escalante Middle Fk Escalante Middle Fir.Escalante Middle Fk Escalante Middle Fk Escalante Middle Fk Escalante Middle Fir.Escalante TatUII IatUII Dry Fk Escalante Dry Fk Escalante Tatum D ESCalante Dry Fk Escalante Tatum D Dry Fk Escalante Dry Fk Escalante Dry Fk Escalante Dry Fk Escalante Dry Fir.Escalante Dry Fir.Escalante Dry Fk Escalante Dry Fk Escalante Dry Fk Escalante Dry Fk Escalante Dry Fk Escalante Dry Fk Escalante Dry Fk Escalante East Fk Escalante Escalante Tatum D Middle Fk Escalante Middle Fk Escalante Middle Fk Escalante East Fir.Escalante East Fk Escalante Middle Fk Escalante Middle Fk Escalante Kelso Middle Fk Escalante Middle Fk Escalante Middle Fk Escalante G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G F F F G G G G Uncompahgre Uncompahgre Beaton Dry Cedar CIt Dry Cedar Ck Fisher Dry Cedar Cir. Gunnison R Dry Cedar Ck Dry Cedar Ck Dry Cedar Cit. Cedar Cir. Dry Cedar Ck Red Rock Can Gunnison Cedar Ck Billy Gunnison Onion Dry Cedar Red Rock Can Dry Cedar Red Rock Can Burro Dry Cedar Loutsenhizer Loutsenhizer Gunnison Cedar Ck Red Rock Can G G G G G G G G G G G G G G G G G F G F F F G F F G G G G G G G G G G F F G F F G G G G G G F G G F F G G G F F G G F F F G F F F ADULT MALE PUMA 122 HE HE SW NW SW SW SW SW SE SW ME SE SE NE HE SW SE SE NW SE SW SE SE NW ME NE SE SE ME 28 20 26 22 22 17 15 28 15 15 14 32 10 34 15 35 23 13 22 23 28 1 35 1 22 19 23 11 1 34 8 8 8 8 8 8 8 8 ·8 8 8 7 8 8 8 8 8 8 8 8 8 8 8 8 8 8 9 9 8 8 2,196 2,196 2,438 2,286 2,256 2,073 2,073 2,196 2,164 2,134 2,408 2,316 2,286 2,196 2,377 2,377 2,347 2,438 2,408 2,286 2,256 2,438 2,256 2,377 2,164 2,225 1,981 1,768 2,499 2,316 8.9 3.2 18.0 2.1 0.3 18.0 19.5 17.2 18.0 0.4 1.5 6.9 6.9 15.0 5.6 5.3 28.0 40.0 32.0 8.0 18.8 15.9 13.0 32.3 16.0 21.3 2.8 2.7 13.6 4.5 G G G G G G G G G G G G G G G G G F G G G G G G G G G F G G F F F G G �217 Legal description Date 1/4 S T U.T.M. R X Y Approx. e1ev (m) Distance (0) between locations Rating Major drainalle Sillo&l Location Adult male I!UDIa'22 - continued 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 3-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 8-88 7-14-88 7-20-88 SE 14 50 9 251 4275 2,042 NW 26 48 262 8 4252 2,499 NW 49 262 1 8 4269 2,347 SE 48 22 8 261 4253 2,286 SE 45 5 8 258 4229 2,256 Scanner aalfunction - Could DOt traclt SE 46 18 256 8 4235 2,225 SE 27 50 8 260 4272 2,347 SW 46 29 8 258 4232 2,256 NW 46 33 8 259 4231 2,225 HE 49 1 8 263 4269 2,377 SW 17 46 8 257 4235 2,164 SW 46 18 8 255 4235 2,286 SE 18 46 8 256 4235 2,225 SW 35 47 8 261 4239 2,164 SW 8 46 257 8 4237 2,134 SW 30 46 265 8 4231 2,256 SE 46 28 259 8 4232 2,134 SW 46 10 8 260 4237 2,196 No location - Fair mollentary signal SW Montrose No location - Fair momentary signal SW Montrose NW 4 46 8 258 4239 2,164 8.8 26.5 17.4 16.5 24.2 Loutsenhizer Dry Cedar Cedar Dry Cedar Dallas G G G G G F G F G G 6.6 37.8 40.5 1.8 39.0 35.0 1.8 1.3 6.6 9.0 5.5 5.0 Fisher Gunnison Uncompahgre Uncompahgre Jones D Fisher Fisher Fisher Chaffee Uncollpahgre Cow Uncompahgre Cow G G G G G G G G G G G G G F G G G G G G F G F G G G 3.2 Uncompahgre G F G G G G G G F G F G F G s.o, ADULT FEMALE PUMA 132 7-19-87 7-24-87 8- 5-87 8- 9-87 8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 10-16-87 10-23-87 10-29-87 11- 6-87 11-13-87 11-20-87 11-28-87 12- 4-87 12-11-87 12-21-87 12-29-87 1-10-88 1-15-88 1-22-88 1-29-88 2- 5-88 2-12-88 2-19-88 2-26-88 SE NW HE SW HE SE NE SW SW SW NE SW NW SE SE SE SE SE NE SW SE SE SW SW NW SW SE SW SW NW SW 28 26 ·23 24 18 24 24 24 24 24 24 17 18 5 17 17 20 20 31 20 30 30 8 17 17 18 18 18 23 19 19 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 46 8 9 9 9 8 9 9 9 9 9 9 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 9 8 8 259 252 252 253 256 254 254 254 254 254 254 257 256 258 258 258 258 257 256 257 256 256 257 257 257 255 256 255 252 255 255 4232 4233 4233 4233 4236 4234 4234 4234 4234 4234 4234 4235 4236 4238 4234 4235 4234 4233 4231 4233 4232 4233 4237 4235 4236 4235 4235 4235 4233 4234 4233 2,103 2,438 2,438 2,377 2,196 2,316 2,316 2,377 2,347 2,347 2,377 2,073 2,196 2,134 2,073 2,196 2,134 2,225 2,377 2,256 2,316 2,286 2,164 2,196 2,134 2,256 2,225 2,286 2,377 2,316 2,377 5.8 7.7 0.6 1.8 3.8 3.3 0.4 0.8 0.1 0.0 0.5 3.5 0.9 2.6 2.5 0.4 1.2 0.6 2.8 2.4 1.3 1.0 5.2 1.8 1.0 2.7 1.3 1.2 4.2 3.2 1.2 Uncompahgre Fisher McKenzie Fisher Fisher Fisher Fisher Fisher Fisher Fisher Fisher Fisher Fisher Uncompahgre Fisher Uncompahgre Uncompahgre Uncompahgre Uncompahgre Uncompahgre Uncompahgre Uncompahgre Uncompahgre Fisher Uncompahgre Fisher Fisher Fisher McKenzie Fisher Fisher 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 3-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 8-88 7-14-88 NW HE HE 28 30 18 30 13 13 8 18 19 30 18 13 32 7 21 27 28 1 35 13 46 46 46 46 46 46 46 46 46 46 46 46 47 46 46 46 46 45 46 46 8 8 8 8 9 9 8 8 8 8 8 9 8 8 8 9 8 9 9 9 258 256 256 256 254 254 257 256 255 256 256 254 257 256 258 251 259 253 252 254 4233 4233 4236 4233 4235 4235 4236 4235 4235 4232 4236 4235 4240 4237 4234 4233 4231 4229 4231 4235 2,164 2,316 2,196 2,3J6 2,286 2,286 2,164 2,225 2,316 2,347 2,225 2,286 2,196 2,377 2,196 2,469 2,225 2,438 2,377 2,286 3.6 2.3 3.8 2.8 3.2 0.4 3.4 1.9 0.4 2.6 4.0 2.1 5.4 3.0 4.5 7.3 8.3 6.6 2.8 4.5 Uncompahgre R Fisher Fisher Fisher McKenzie McKenzie Uncompahgre Fisher Fisher Uncompahgre Fisher McKenzie Uncompahgre McKenzie Uncompahgre Fisher Uncompahgre Pleasant Valley Cit Fisher McKenzie !'!E HE SE SW SW NW SE HE SE SW NW SW NE SE SW HE SE R R R R R R R R R R G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G F F G G G G F G G F G G Visual G also G G G ··F G G G G G G G G G G G G G G G G G G G F G G G G G F G G G G G G G G G F �218 Legal description Date 1/4 S NW SW SE SE NE SW '19 19 22 22 27 5 8 4 27 7 7 19 4 8 8 12 13 12 31 24 35 24 14 19 18 12 30 26 13 . 12 18 12 6 13 7 13 33 12 13 7 35 18 6 5 36 5 35 20 31 34 6 T U.T.K. R X Approx. elev (m) Y Distaoce (0) between locations Ratiog Major drainase Sisnal Location SUBADULT FEMALE PUMA 134 7-19-87 7-24-87 8- 5-87 8- 9-87 8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 10-16-87 10-23-87 10-29-87 ll-6-87 ll-13-87 ll-20-87 ll-28-87 12- 4-87 12-ll-87 12-21-87 12-29-87 1- 8-88 1-15-88 1-22-88 1-29-88 2- 5-88 2-12-88 2-19-88 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 3-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 8-88 7-14-88 liE NW liE NW SW SE SW liE liE SE NE SE SW HE NW HE SE SW NW SE SW NE NW SE NW SE NW HE NW NW SW SE NW SW NE NE SE SE HE HE HE SW SE NW SE 47 47 47 47 47 46 46 46 47 46 46 46 46 46 46 47 48 47 48 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 47 46 46 47 46 47 48 47 46 46 9 9 10 10 10 9 9 9 9 9 9 9 9 9 9 10 10 10 9 10 10 10 10 9 9 10 9 10 10 10 9 10 9 10 9 10 9 10 10 9 10 9 9 9 10 9 10 9 9 9 10 245 245 242 242 241 247 248 249 251 246 246 246 249 248 248 245 245 245 246 244 242 244 243 246 245 245 245 243 244 245 245 245 246 244 246 244 249 245 244 245 243 247 246 248 245 248 243 247 246 250 246 4245 4244 4244 4244 4243 4238 4238 4239 4243 4238 4237 4234 4239 4238 4237 4247 4246 4247 4250 4244 4241 4244 4245 4244 4246 4247 4242 4243 4246 4246 4246 4247 4249 4246 4248 4246 4239 4247 4245 4247 4241 4245 4238 4238 4241 4239 4241 4253 4240 4241 4238 2,256 2,256 2,377 2,408 2,438 2,438 2,377 2,377 2,103 2,469 2,499 2,621 2,316 2,408 2,438 2,225 2,196 2,134 2,012 2,286 2,469 2,196 2,256 2,256 2,134 2,103 2,316 2,316 2,164 2,134 2,134 2,196 2,042 2,225 2,134 2,196 2,256 2,134 2,256 2,134 2,469 2,164 2,408 2,377 2,347 2,347 2,438 1,890 2,408 2,164 2,438 4.1 1.0 3.6 0.4 1.1 7.0 1.5 1.4 4.1 7.9 0.6 3.7 5.5 1.2 0.5 9.8 0.7 0.4 3.6 5.0 4.3 4.1 1.5 2.8 2.3 1.5 5.0 2.0 3.5 1.0 0.4 0.7 2.7 3.5 2.3 2.7 7.9 8.0 2.5 1.5 6.0 5.5 6.8 2.0 4.4 3.3 4.7 12.1 5.0 4.1 5.1 Dolores DoloreB Happy Happy Happy W FIt Horsefly E FItHor8efly E Fk HorBefly HorBefly W FItHorsefly W FItHorsefly E FIt Horsefly E FItHorsefly E FIt Horsefly E FIt Horsefly Happy Happy Happy Happy Happy Happy Happy Happy DoloreB Happy Happy Dolnres Happy Happy Happy Happy Happy Happy Happy Dolores Happy Horsefly Happy Happy Happy Dolores Dolores W Fk Horsefly Cottoowood Dolores W Fk Horsefly Dolores Happy Wildcat Horsefly W FIt Horsefly G G G G G G G G F F G G G G F G a a a a a a a a a a a a a a G G G G G a a a a a a G a G a G a a a F F a a a a a a a a F a a a a F F a G a a a a G G G G G a G a a a G G a a G a G a a F G F a G G F G F a a S UBADULT FE.'!ALEPUMA 136 47 23 7-19-87 SE 8 14 47 7-24-87 SE 8 48 8- 5-87 NW 25 8 48 22 8- 9-87 NW 8 48 22 8-16-87 SW 8 48 21 8-28-87 SE S 48 21 9- 4-87 SE 8 22 48 SW 8 9- 5-87 Cause of death DOt established: 4243 262 2,286 1.6 Ooioo Ck 4244 262 2,347 1.5 Onioo Ck 4251 2,499 263 7.0 Beatoo 4254 261 2,225 3.5 Dry Cedar 4253 260 2,256 0.7 Dry Cedar 260 4253 2,134 0.4 Dry Cedar 4253 2,134 260 0.0 Dry Cedar 4253 261 2,256 0.0 A sharp booe (aviao 7) about 12" 100g va. found io a G G Ck Ck Ck Ck a a G ~brtality Fouod Dead stomach. F F F F F F SlgUoi SUBADULT FEMALE PUMA 137 7-19-87 7-24-87 8- 5-87 8- 9-87 8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 SE SE NE HE NW SW SE SE NE SW SE SE 13 23 II 11 24 24 35 11 24 35 13 26 48 48 48 48 48 48 48 48 48 48 48 48 12 12 12 12 12 12 12 12 12 12 12 12 750 748 748 747 749 749 748 748 749 748 749 748 4255 4253 4257 4257 4254 4253 4250 4256 4254 4250 4254 4253 2,469 2,560 2,408 2,377 2,438 2,256 2,621 2,499 2,408 2,591 2,469 2,560 0.7 1.5 3.9 0.4 4.2 0.6 3.1 6.4 3.1 6.6 4.8 1.7 West Fk Dry Ck Piney Cushman Cushman West FItDry Ck West FItDry Ck arsys Ck Cushmsn W Fk Dry Ck W Fk Dry Ck W FItDry Ck Pi~ey a G G a G G G a a a a a F F F G G F G G G a F G �219 Legal description Date Subadult 1/4 S T U.T.M. R X Y Appro:.:. elev (m) Distance (u) between locations RatiDg Major draioase Sisnal Location female ~uma 137 - continued 10-16-87 10-23-87 10-29-87 11-6-87 11-13-87 11-20-87 11-28-87 12-11-87 12-21-87 12-29-87 1- 8-88 1-15-88 1-22-88 1-29-88 2- 5-88 2-12-88 2-19-88 2-26-88 .3- 4-88 .3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 3-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 3-88 NW NW SE HE HE 5W sw 7-19-87 7-24-87 8- 5-87 8- 9-87 8-16-87 8-28-87 8-30-87 SE NE NE SE SE NE NE 24 48 12 36 48 12 23 48 12 24 48 12 48 26 12 24 48 12 19 48 11 NW 24 48 12 5E 24 48 12 5w 19 48 11 SE 48 18 11 SW 8 48 11 NW 17 48 11 HE 18 48 11 NW 48 17 11 NW 22 48 11 NW 9 48 11 5W 48 16 11 5W 48 22 11 HE 24 48 11 5E 7 48 11 5W 48 12 1 5W 48 12 1 5W 48 12 13 48 5E 12 35 5W 48 25 12 48 HE 22 12 5E 2 47 12 48 SE 12 35 5W 48 36 12 SW 36 48 12 48 SE 13 12 NW 24 48 12 SE 48 12 35 NW 47 12 12 SW 47 12 1 Shot as sheeplt111er 748 749 748 749 748 749 750 750 749 750 751 752 752 751 752 755 754 753 755 750 751 749 749 749 748 749 747 748 748 749 748 749 749 748 749 749 4254 4251 4253 4254 4252 4253 4253 4254 4253 4253 4255 4256 4255 4255 4256 4254 4257 4255 4254 4254 4256 4258 4258 4255 4250 4251 4254 4248 4250 4250 4250 4254 4254 4249 4248 4248 2,530 2,499 2,560 2,469 2,560 2,530 2,469 2,469 2,377 2,377 2,286 2,196 2,256 2,256 2,042 2,134 2,012 2,196 2,196 2,408 2,256 2,347 2,347 2,438 2,621 2,499 2,499 2,714 2,621 2,591 2,652 2,530 2,499 2,652 2,591 2,621 0.6 2.6 1.8 1.8 2.7 1.6 1.4 1.2 0.7 1.2 1.4 2.7 0.7 0.8 1.4 3.3 3.1 2.0 2.6 6.0 2.8 3.4 0.2 3.1 4.6 1.6 3.7 5.2 1.4 1.1 0.2 4.7 0.3 4.3 1.3 0.9 w FIt Dry Cit W Fit Dry Cit Piney w FIt Dry Cit Piney w FIt Dry Cit w FIt Dry Cit w FIt Dry Cit w FIt Dry Cit w FIt Dry Cit w FIt Dry Cit W FIt Dry Cit W FIt Dry Cit w FIt Dry Cit W FIt Dry cit E FIt Dry CIt E FIt Dry Cit E FIt Dry CIt E FIt Dry CIt w FIt Dry Cit W FIt Dry Cit Cushman Cushman Piney Gray's Cit W FIt Dry Cit Cushman W FIt Dry Cit Gray's Cit W Fit Dry Cit I< FIt Dry Cit Piney Piney W fit Dry Cit I< FIt Dry CIt I< Fit Dry Cit I< FIt Dry Cit G G G G G G G G G G G G G G G G G G G G G G G E E E E E E E G G G G F G G F G G F F G G F G G G G F G F G G G G G G G G G G G G G G G G G G G G G G G G G G G F G G G F F G ADULT MALE PUMA 138 34 3 3 34 34 3 3 Probably 48 47 47 48 48 48 48 11 11 11 11 11 11 11 756 756 756 756 756 756 756 4250 4249 4250 4250 4250 4250 4250 2,438 2,438 2,408 2,560 2,560 2,560 2,469 died between 5-15 and 5-22-87; 0.4 0.8 0.6 0.3 0.0 0.0 FIt Dry FIt Dry FIt Dry FIt Dry FIt Dry fk Dry fit Dry Ck Cit Cit Cit Ck Ck Ck F G C G G Mortality Signal Nonfunctional cause of deatb unknown ADULT MALE PUMA 140 7-19-87 7-24-87 8- 5-87 8- 9-87 8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 10-16-87 10-23-87 10-29-87 11- 6-87 11-13-87 11-20-87 11-28-87 12- 4-87 12-11-87 12-21-87 12-29-87 1-10-88 1-15-88 1-22-88 NW NW NE NE 51< NW SW SI< NW 5E NW NW NE NE NW NW NE NW sw NW NW NE HE NE 5W SE 9 17 1 28 23 7 28 22 8 18 8 27 8 5 27 20 10 8 5 32 17 17 2 5 21 20 45 45 45 46 46 45 46 46 45 46 46 46 45 45 46 46 45 45 46 46 45 46 45 45 46 46 9 9 10 9 9 98 9 9 8 8 9 9 8 9 8 9 9 8 8 9 9 9 8 8 8 248 247 244 250 252 245 259 250 246 257 257 250 248 258 250 257 250 247 257 255 247 248 252 257 258 258 4228 4227 4229 4233 4233 4228 4232 4233 4228 4235 4238 4233 4228 4229 4233 4234 4228 4228 4238 4239 4227 4236 4229 4229 4233 4233 2,714 2,438 2,836 2,530 2,408 2,928 2,134 2,499 2,745 2,225 2,225 2,530 2,621 2,347 2,499 2,103 2,499 2,652 2,134 2,377 2,438 2,438 2,499 2,438 2,196 2,164 7.9 1.8 3.7 6.4 2.1 8.7 14.4 9.1 6.3 11.9 2.5 8.1 5.4 10.3 8.2 6.9 9.5 3.7 15.0 7.3 9.5 9.9 8.5 4.8 4.6 0.5 Pleasant V Pleasant V McKenzie McKenzie McKenzie Pleasant V Uncompahgre McKenzie Pleasant V Fisher McKenzie McKenzie Pleasant V Dallas McKenzie Uncompahgre Pleasant V Pleasant V Uncompahgre Uncompahgre Pleasant V E fk IIorsefly Dallas Dallas Uncompahgre Uncompahgre G G G G G G G G G G G G G G G G G G G G G G G G G G F F G F F G G G G G G G G G G G G G G F G G G C r G �220 Legal description Date 1/4 S T U.I.M. R X Di8t8nce Appro>:. e1ev (m) y (lcm) between Rating locations Major drainase 4.1 3.2 8.7 11.8 8.5 7.0 13.0 13.5 0.6 3.7 4.3 0.4 6.2 7.7 0.2 0.3 1.0 10.7 13.0 3.1 6.4 9.1 0.8 1.0 Uncompahgre Fisher W FIt Horsefly Pleasant V Dallas Pleasant V Horsefly Pleasant V Pleasant V Dallas Uncompahgre Uncompahgre McJ(e=ie E FIt Horsefly E FIt Horaefly E FIt Horsefly Busted Boller D Pleasant V Cit Uncompahgre Fisher Dallas E FIt Horsefly E FIt Horsefly Busted Boller Sisna1 location Adult male 2WD8 140 - ~ont1nued 1-29-88 2- 5-88 2-12-88 2-19-88 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-22-88 4-29-88 s- 7-88 5-14-88 5-20-88 5-27-88 6- 3-88 6-10-88 6-17-88 6-30-88 7- 8-88 7-14-88 HE SE NW HE ME HE NW HE NW SW NW SW HE NW NW HE HE SE HE SW HE NW SW HE 8 18 4 9 5 10 34 10 11 6 33 28 7 16 16 6 16 18 32 17 1 16 16 16 46 46 46 45 45 45 46 45 47 45 46 46 46 46 46 46 46 45 46 46 45 46 46 46 8 8 9 9 8 9 9 9 9 8 8 8 8 9 9 9 9 9 8 8 9 9 9 9 258 256 248 249 258 251 250 251 251 255 259 259 256 249 249 749 249 246 259 257 254 249 249 249 4238 4235 4240 4228 4229 4228 4241 4228 4228 4229 4231 4032 4238 4236 4236 4236 4236 4225 4231 4235 4329 4236 4236 4236 2,103 2,225 2,316 2,560 2,316 2,591 2,164 2,530 2,499 2,316 2,256 2,225 2,256 2,408 2,438 2,438 2,438 2,714 2,286 2,164 2,408 2,377 2,438 2,377 G G G G G G G G G G G G G G G G G G G G G G G G G F G G G F G G G G G G G F G G F G G F G G G F SUBADULT MALE PUMA #42 1-21-88 1-22-88 2-18-88 3-17-88 4-20-88 5-10-88 5-25-88 6-10-88 6-29-88 7-12-88 SE HE NW SE ME HE SW NW SW NW aAl1 locations 31 29 33 1 10 27 36 20 10 23 3 3 2 3 2 4 4 4 5 5 by Wildlife 86a 86 86 88 86 87 87 87 87 87 318 318 323 310 328 314 319 311 '311 315 4401 4403 4410 4410 4418 4389 4391 4381 4386 4370 124.0 3.0 8.0 14.0 19.0 27.0 4.0 10.0 10.0 2.0 Sweetwater Horse E FIt Red Cit Sweetwater Derby Deep Colorado R Deep Tie Gulch Jaclt Cit Recapture Recapture Biologist G. Byrne ADULT MALE PUMA #44 7-19-87 7-24-87 8- 5-87 8- 9-87 8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 10-16-87 10-23-87 10-29-87 11- 6-87 11-13-87 11-20-87 11-28-87 12- 4-87 12-11-87 12-21-87 12-29-87 1- 8-88 1-15-88 1-22-88 1-29-88 2- 5-88 2-12-88 2-19-88 2-26-88 3- 4-88 3-18-88 3-25-88 4- 2-88 4-15-88 4-22-88 SE SE SW NW SW NW NW SW ME SE SW SW HE HE SW SE SE SW SE HE HE SE SE ME SW SE NW NW NW NE NE NE SW NW ME NW SW 34 24 17 16 7 29 30 17 9 34 31 25 10 17 17 18 15 30 21 4 33 21 19 17 21 8 10 36 16 25 16 19 27 10 2 29 18 15 15 51 15 51 15 15 15 15 15 15 15 15 15 15 15 51 15 15 50 14 15 15 15 15 15 15 14 15 15 15 15 14 51 15 51 51 101 101 15 101 15 100 100 100 101 101 100 101 100 100 101 100 17 100 100 17 100 15 99 100 100 99 100 100 99 100 99 99 100 15 99 15 14 703 706 712 701 709 708 706 708 702 702 707 705 712 709 699 707 696 707 711 694 711 711 717 709 710 719 712 715 720 715 720 718 711 714 724 715 719 4285 4289 4284 4291 4285 4288 4288 4291 4293 4285 4285 4285 4293 4291 4290 4291 4283 4287 4289 4277 4296 4289 4289 4292 4289 4292 4293 4297 4292 4288 4292 4290 4298 4285 4295 4281 4284 2,530 2,560 2,438 2,591 2,560 2,408 2,377 2,286 2,530 2,560 2,499 2,499 2,225 2,377 2,652 2,438 2,682 2,560 2,286 2,256 2,286 2,316 2,408 2,286 2,377 2,286 2,286 2,134 2,286 2,469 2,196 2,408 2,286 2,377 2,073 2,408 2,164 1.5 5.0 2.7 13.2 11.0 3.6 1.0 2.6 8.5 7.7 5.2 2.5 9.2 3.7 10.0 8.5 13.9 12.2 1.8 20.0 25.2 6.9 6.3 8.8 3.2 10.2 7.5 4.7 0.6 5.4 6.1 3.2 9.9 12.9 13.7 18.7 8.1 Lafair Big Dominguez Keith N ern Cit Keith Cit Big Dominguez Big Dominguez Big Dominguez West Beaver Big Dominguez Smith GUbler Big Dominguez Gill Big Dominguez Cow Cit Big Dominguez Big Dominguez Indian Gibb1er Big Dominguez Wlldhorse D Roclty Pitch Gulch Big Dominguez Dry FIt Big Dominguez Gibb1er GUbler Little Dominguez Wlldhorse D Little Dominguez Little Dominguez Farmer's Little Dominguez Dry Fit Big Dominguez Keith Cit Rose Cit G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G F F F F G G G G G F G G G G G G G G G F F G G F F F F F F G F F G F F G F �221 Legal description Date ---------1/4 S T R U.T.M. X Y Approx. e1ev (m) Distance (km) between locations Rating Major drainalle Si~a1 Location Adult male Euma 144 - continued 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 3-88 6-17-88 6-23-88 6-30-88 7- 8-88 SW SE SW SW HE HE SE NW HE SW 16 4 35 30 35 17 4 2 31 22 51 50 51 51 15 50 15 15 15 15 15 15 15 15 101 15 99 101 100 100 713 714 715 710 705 712 720 703 708 711 4283 4277 4279 4280 4285 4275 4294 4294 4286 4289 2,408 2,682 2,621 2,499 2,469 2,560 2,134 2,408 2,499 2,225 6.4 5.9 2.6 5.8 8.0 13.5 20.8 17.2 9.1 5.0 Keith CIt Corral G Corral G Keith Smith H fit Escalante Big Dominguez West Big Dominguez Big Dominguez G G G G G G G G G G F G F F G F F F G G Traver Criswell Monitor Potter Terrible Moore Traver Criswell Traver Coa1bank Roubideau Cushman Criswell Criswell Wright Roubideau Criswell Moore Roubideau Potter Moore Criswell Potter Criswell Roubideau Potter Criswell Criswell Roubideau Criswell Roubideau Potter Roubideau Criswell G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G F F F F F G G G G G G G F G G G G G F G G G G G G G F F G Roubideau Roubideau Roubideau Roubideau Roubideau Roubideau Roubideau Roubideau Moore Roubideau Traver Roubideau Wright Traver G G G G G G G G G G G G G G F F F F F G F F F F F G G F G F G F F ADULT FEMALE PUMA 145 7-19-87 7-24-87 8- 5-87 8- 9-87 8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 10-16-87 10-23-87 10-29-87 11- 6-87 11-13-87 11-20-87 11-2li-87 12- 4-87 12-11-87 12-21-87 12-29-87 1- 8-88 1-15-88 1-22-88 1-29-88 2- 5-88 2-12-88 2-19-88 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 3-88 6-10-88 6-23-88 6-30-88 7- 8-88 7-14-88 SE SW 29 49 12 741 4262 2,196 2.9 23 50 12 745 4273 12.2 1,859 15 49 13 734 4265 2,438 13.3 SE 22 49 13 734 4263 2,377 2.2 NW 5 48 12 742 4259 2,377 8.4 SE 9 49 12 742 4266 1,951 7.2 NW 29 49 12 740 4262 2,408 4.5 NW 24 49 13 737 4264 2,316 3.2 NW 29 49 12 740 4263 2,377 3.1 SE 9 49 11 752 4267 1,890 12.6 SW 10 50 12 744 4276 1,890 11.9 SE 29 49 11 751 4262 2,164 15.7 NE 5 49 12 741 4269 2,103 11.7 SW 19 49 12 740 4263 2,286 6.4 NW 33 49 12 742 4261 2,164 3.1 SE 4 49 12 743 4268 1,951 7.4 SW 4 49 12 742 4269 1,951 1.1 sO' 20 49 12 740 4263 2,256 5.3 NI,' 16 49 742 12 4266 2,012 3.1 SW 31 50 12 740 4270 1,981 4.8 NE 17 49 12 742 4266 2,164 4.4 NW 4 49 12 742 4269 1,920 4.0 NE 32 50 12 741 4271 2,012 1.6 NW 4 49 12 742 4269 1,890 1.9 HE 35 50 12 745 4271 1,890 5.1 SW 31 12 50 739 4270 2,103 6.4 SW 27 50 12 743 4272 1,920 4.6 NW 9 49 12 742 4267 2,103 4.7 SW 34 50 12 743 4270 1,981 2.9 SE 33 50 12 743 4270 1,859 1.0 NE 3 49 12 744 4269 1,798 2.1 SE 21 50 12 742 4273 1,951 4.3 SE 4 49 12 743 4268 1,829 4.7 HE 33 50 12 743 4271 1,829 2.5 No location - Poor signal over Criswell, Moore, and Roubideau No signal - Extensive search HE 3 49 744 12 4269 1,768 2.0 SE 4 49 12 743 4268 1,951 1.6 SE 4 49 12 743 4269 1,951 0.2 NW 3 49 12 743 4270 2,316 1.2 SW 744 3 49 12 4269 1,829 1.0 NW 21 49 12 742 4265 2,164 4.4 SE 49 9 12 743 4266 1,859 2.0 NE 16 49 12 743 4266 1,920 0.2 SW ·16 49 742 4265 12 2,073 5.5 HE 16 49 4266 12 743 1,920 1.2 SE 49 29 12 742 4261 2,196 4.5 SE 21 49 12 743 4264 1,951 2.7 NW 33 49 12 742 4261 2,042 2.7 SW 28 49 12 742 4262 1,981 0.7 NW F F F G G ADULT FEMALE PUMA 146 7-19-87 SE 32 51 15 711 4279 2,438 ll.6 Red Ck 7-24-87 SE 16 51 15 714 4284 2,316 5.4 Keith Ck 8- 5-87 HE 28 51 714 15 4281 2,316 2.4 Red Ck 8- 9-87 SI:: 32 51 702 16 4279 2,682 11.5 Big Dominguez Found dead during first week in August by C. Black - Cause of death unknown G G G Black had removed collar and took same to his summer camp just south of Coldwater Ranger Station where I aerially located it on 8-9-87. G. Bock picked up skull from carcaas in mid-August. The approximate location was SE 1/4, 517, T51N, Rl5W 712-4283 7,900' on N Fk of Keitb Ck by Stockpond. �222 Legal description Date 1/4 S T R U.I.M. X Y Appro",. e1ev (m) Distance (kID) between locations Rating Major drainal!e Sis:!!al Location SUBADULI MALE PUMA #47 7-19-87 7-24-87 8- 5-87 8- 9-87 8-16-87 8-28-87 9- 4-87 12- 4-87 12-11-87 12-21-87 12-29-87 1-10-88 1-15-88 1-22-88 1-29-88 2- 5-88 2-12-88 2-19-88 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 8-88 SW SW 29 36 12 8 7 24 21 29 35 32 22 1 26 11 15 7 3 31 32 23 27 32 5 6 34 33 25 3 33 30 23 3 14 3 29 35 13 13 14 13 13 13 13 13 13 13 13 14 12 12 12 12 12 11 11 11 11 20 21 21 12 12 13 14 13 13 13 13 13 13 13 11 103 679 104 676 103 685 102 688 102 688 103 685 102 690 103 679 104 675 103 679 104 673 103 686 103 684 103 684 103 684 103 677 103 682 102 686 102 688 103 684 103- 681 26 667 26 667 26 665 102 691 102 691 101 685 104 672 102 691 101 697 102 694 104 673 102 243 102 692 101 685 103 _684 4306 4304 4303 4312 4312 4309 4308 4306 4305 4306 4309 4304 4317 4322 4320 4322 4323 4324 4325 4328 4327 4321 4319 4319 4315 4315 4207 4304 4306 4308 4309 4312 4310 4314 4207 4325 7.0 3.9 10.1 11.0 - 0.6 4.3 1.0 11.8 4.2 4.4 6.7 14.0 15.0 4.7 1.4 5.9 4.7 5.0 1.5 5.0 2.5 15.0 1.6 2.3 25.2 0.9 9.2 13.2 18.3 6.6 3.0 21.3 20.6 3.6 8.9 17.8 Briar Can KcXetl%ie Sheep Clark Wash Clark Wash Dierich Ck Little Dolores Briar McKenzie Briar Hill T Dodson Can Trail Can Sieber Can - Sieber Can Little Dolores R Seiber Can Seiber Can 28-Hole Wash Kee Knowles Jones Little Dolores Little Dolores Clark Wash Payne Wash Dierich Granite Little Dolores Ladder Clark Wash Coates Clark Wash Clark Wash Dierich 28-Hole Wash G G G G G G G G G G G 7-19-87 SE 10 47 11 756 4247 2,438 1.7 E Fk Dry Ck 7-24-87 SW 21 48 11 754 4253 2,316 0.7 E Fk Dry Ck 8- 5-87 HE 11 47 11 758 4249 2,469 6.8 E Fk Dry Ck 8- 9-87 SW 2 47 11 4248 757 2,438 1.9 E Fk Dry Ck 8-16-87 HE 4 47 11 755 4249 2,438 2.8 E Fk Dry Ck 8-28-87 SW 27 48 11 755 4252 2,286 3.3 E Fk Dry Ck 9- 4-87 SE 10 47 11 756 4246 2,560 4.5 E Fk Dry Ck 9-13-87 34 11 SW 48 755 4250 2,408 3.4 E Fk Dry Ck 9-18-87 HW 27 48 11 756 4252 2,164 2.4 E Fk Dry Ck 9-26-87 SE 34 48 11 756 4250 2,438 2.0 E Fk Dry Ck 10- 2-87 HE 47 11 753 5 4249 2,560 3.2 E Fk Dry Ck 10- 9-87 NW 4244 20 47 11 752 2,806 4.6 E Fk Dry Ck 10-16-87 SW 33 48 11 754 4250 2,530 5.7 E Fk Dry Ck 10-23-87 HE 4245 19 47 11 752 2,682 4.6 E Fk Dry Ck 10-29-87 SW 11 755 4250 34 48 2,408 6.2 E Fk Dry Ck 11-6-87 4251 HE 34 48 11 756 2,316 1.2 EFkDzyCk 11-13-87 11 4247 SE 10 47 756 2,499 3.8 E Fk Dry Ck 11-20-87 4244 HW 19 47 10 760 2,438 5.3 KiddIe Fk Spring 11-28-87 4254 HE 21 48 11 754 2,103 11.8 E Fk Dry Ck ;., 11 12- 4-87 4241 SW 759 36 2,682 5.6 KiddIe Fk Spring 12-21-87 4240 SW 241 34 47 10 2,530 7.6 Happy 12-29-87 SW 4240 32 47 10 762 2,682 4.1 E Fk Spring 1- 8-88 HW 4251 35 48 11 757 2,377 11.5 W Coal Ck 1-15-88 HE 29 4243 47 238 2,499 10 6.1 E Fk Spring 1-22-88 No location - Poor signal vicinity of 1-15-88 location; 1/2-hr search 1-29-88 SW 4250 31 48 10 760 2,286 8.0 Lindsay Can 2-12-88 HE 4240 5 46 9 248 2,286 16.5 W Fk Horsefly 2-19-88 HW 4237 9 46 249 2,347 9 2.4 E Fk Horsefly 2-26-88 HE 4239 5 46 8 248 2,347 2.2 W Fk Horsefly Found dead from unknown causes 2-27-88; skull and radioco11ar recovered G G G G G G HW HW HE HW SW SW SE HW HE HE HW HW HE HW HW SW HW SW HW HW HW SW SW HE HW HW HW HW NE SE SW SW HW HW 2,438· 2,560 2,682 2,134 2,164 2,225 2,316 2,438 2,499 2,377 2,316 2,560 2,012 1,920 1,951 1,890 1,890 1,981 1,981 1,829 1,829 1,646 1,707 1,586 2,073 2,073 2,408 2,499 2,377 2,652 2,377 2,196 2,347 2,196 2,408 1,890 G G G G G G G G G G G G G G G G G G G G G G G G G F F F F G F G F F F F G F F F G G G F F G F F G F F G G G F F G G G G G SUBADULI MALE PUMA #50 G G G G F F F G G G G G G G G G G F F G G G G G G G G G G G G G G G Mortality Mortality G G G G G G G F G G F G F G �223 Legal description U.T.M. Approx. e1ev (m) 1/4 5 r R 7-19-87 7-24-87 8- 5-87 8- 9-87 .8-16-87 8-28-87 9- 4-87 9-13-87 9-18-87 9-26-87 10- 2-87 10- 9-87 10-16-87 10-23-87 10-29-87 11- 6-87 11-13-87 11-20-87 11-28-87 12- 4-87 12-11-87 12-21-87 12-29-87 1- 8-88 1-15-88 1-22-88 1-29-88 2- 5-88 2-12-88 2-19-88 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 3-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 8-88 7-14-88 SE HE SE SW HE SW HE SW HE HE SW HE NW NW SE NW NW SW NW NW SW SE SE SW SE NW NW SE NW NW NW HE SE NE SW NW NW NE SW HE HE SW SW HE NW SE SE HE HE SW SE 5 8 33 4 8 4 35 26 22 18 28 7 16 30 7 9 34 5 4 34 30 19 9 28 18 4 7 5 34 21 18 27 18 21 32 29 4 22 33 1 24 19 24 5 8 9 5 16 24 9 8 46 46 47 46 46 46 47 47 47 47 47 46 46 47 46 47 47 46 46 47 47 47 46 47 47 46 47 46 47 47 47 47 47 47 47 47 46 47 47 46 47 47 47 46 46 46 46 46 46 46 47 9 9 9 9 9 9 10 10 9 9 9 9 9 9 8 9 9 9 9 9 9 9 9 9 9 9 9 9 10 9 9 9 9 9 8 9 9 9 9 10 10 9 10 9 9 9 8 9 10 9 9 248 248 249 249 248 249 243 242 252 247 249 246 249 245 256 249 251 247 249 250 246 246 249 249 246 249 245 248 250 249 245 251 747 250 256 247 249 251 249 245 244 245 244 248 247 249 258 249 245 249 247 4239 4238 4240 4239 4238 4238 4241 4242 4244 4246 4242 4238 4236 4243 4237 4247 4241 4239 4239 4240 4242 4244 4236 4241 4245 4239 4247 4238 4241 4244 4246 4243 4245 4244 4240 4243 4239 4244 4240 4239 4244 4244 4243 4240 4237 4237 4238 4236 4234 4237 4245 2,377 2,377 2,347 2,316 2,408 2,377 2,438 2,438 2,042 2,225 2,225 2,438 2,408 2,316 2,225 2,012 2,134 2,408 2,316 2,164 2,347 2,347 2,347 2,256 2,134 2,256 2,134 2,408 2,164 2,225 2,134 2,103 2,256 2,134 2,196 2,286 2,256 2,073 2,316 2,438 2,256 2,256 2,256 2,377 2,438 2,408 2,164 2,408 2,621 2,438 2,196 12-19-87 12-21-87 12-29-87 1- 8-88 1-15-88 1-22-88 1-29-88 2- 5-'88 2-12-88 2-19-88 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 .4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 3-88 6-10-88 &-17-88 6-23-88 6-30-88 7- 8-88 7-14-88 HE SW SW SE 8 19 27 9 16 27 9 4 9 9 36 16 22 16 27 28 28 27 9 16 17 8 21 16 17 9 22 21 18 20 20 48 48 48 48 48 48 48 48 48 48 49 48 48 48 48 48 48 48 48 48 48 48 48 48 48 48 48 48 48 48 48 11 11 11 11 11 11 11 :11 11 11 11 753 751 756 754 754 756 755 754 754 755 756 755 756 754 755 754 755 755 753 753 752 753 754 754 753 754 755 754 751 753 753 4257 4253 4252 4257 4255 4251 4258 4258 4258 4257 4260 4255 4254 4255 4253 4253 4252 4252 4256 4256 4256 4257 4254 4255 4256 4257 4253 4253 4255 4253 4254 1,981 2,397 2,408 1,951 2,012 2,347 2,103 1,981 2,073 2,073 2,073 2,134 2,225 2,134 2,256 2,286 2,286 2,408 2,134 2,164 2,012 2,073 2,256 2,134 2,164 1,920 2,256 2,256 2,196 2,286 2,256 Date X Y Distance (Iaa) between locations Rating Major draInase SIsna1 Locatio) ADULT MALE PUMA 152 1.6 0.9 2.1 1.3 1.1 0.6 5.7 1.4 9.8 5.1 5.7 3.6 3.6 8.3 12.4 13.0 ~.6 4.4 2.5 2.8 4.7 1.5 7.0 4.2 4.3 6.4 9.0 9.5 3.6 3.6 4.0 6.5 4.8 3.1 7.7 9.7 4.1 5.5 4.2 3.9 4.7 1.1 1.2 2.3 2.3 2.3 8.2 8.5 5.1 4.5 8.5 Horsefly Horsefly Horsefly Horsefly Horsefly E Fit Horsefly Dolores Happy Horsefly Dolores Wildcat W FIt Horsefly E FIt Horsefly Dolores McKenzie Dolores Horsefly W FIt Horsefly E FIt Horsefly Horsefly Dolores Dolores E FIt Horsefly Wildcst Can Dolores Horsefly Happy E FIt Horsefly Horsefly Horsefly Happy Horsefly Dolores Wildcst Uncompshgre Horsefly E FIt Horsefly Horsefly Horsefly Dolores Happy Happy Happy W FIt Horsefly E FIt Horsefly E Fk Horsefly Uncompahgre Busted Boiler D Cottonwood E FIt Horsefly Dolores G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G F F F P F G G G G F G G G G F G G G G G G G F G G F F G F G G G F G F G G G F G G G G F F G G F G G FEMALE PUMA #53 sw SE HE SW NW HE SW SW NW SW HE NE NE SW SW NW NW HE NW SW HE NW SW SW HE SE HE II 11 II 11 II 11 II 11 II 11 II 11 11 11 II 11 II 11 II 11 Capture 5.2 5.3 5.3 1.5 4.2 6.1 1.1 0.3 1.2 3.8 5.9 1.4 2.0 2.2 0.9 0.7 0.6 4.5 0.7 1.2 1.5 3.6 1.2 1.0 1.7 4.2 0.9 3.2 2.7 1.0 W FIt Dry w FIt Dry E FIt Dry E FIt Dry E FIt Dry E FIt Dry E Fit Dry Dry Cit W FIt Dry E FIt Dry Dry Cit E FIt Dry E Fit Dry E FIt Dry E FIt Dry E FIt Dry E FIt Dry E FIt Dry E FIt Dry E Fit Dry W Fit Dry W Fit Dry E Fit Dry E Fit Dry E Fit Dry E Fit Dry E FIt Dry E FIt Dry W Fit Dry E Fit Dry E FIt Dry Cit CIt CIt CIt CIt CIt cit CIt Cit CIt Cit Cit Cit Cit Cit Cit Cit Cit Cit Cit Ck Cit CIt Cit Cit CIt Cit Cit Cit G G G G G G G G G G G G G G c .,; G G G G G G G G G G G G G G G G G G G G G G F G F F G F G G G F F G F G G G G F G G G G �224 Legal d~scription Date 1/4 S T U.T.M. R X Y Appro". ~lev (m) Distanc~ (0) between locations Rating Major drainalle Si!l!!!!l Location FEMALE PUMA 154 1-11-88 1-15-88 1-22-88 1-29-88 2- 5-88 2-12-88 2-19-88 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 4-22-88 4-29-88 s- 7-88 5-14-88 5-20-88 5-27-88 6- 4-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 8-88 7-14-88 NIl NIl NIl SW HE HE NIl NIl SW SE HE SE SE SE NIl SW SE HE SE HE SE SE NIl SE NIl SE SE NIl 27 27 26 12 25 30 26 26 12 12 8 4 34 4 36 4 5 31 36 34 13 33 19 23 19 19 24 19 50 50 50 50 15 14 14 14 14 14 14 14 14 14 13 14 14 13 13 13 13 12 12 12 12 12 12 12 14 14 14 14 98 3 98 98 97 97 97 96 96 96 96 97 96 96 97 96 96 95 94 95 95 95 96 95 724 724 726 727 735 735 732 732 743 744 747 749 750 749 753 748 748 746 744 751 754 759 244 243 755 755 754 754 4272 4272 4272 4276 4289 4296 4298 4298 4303 4303 4304 4304 4305 4305 4307 4303 4304 4306 4306 4307 4311 4216 4320 4320 4320 4320 4319 4320 1,861 1,859 2,012 2,225 1,737 1,556 1,951 1,646 1,890 2,012 2,134 2,347 2,316 2,225 2,134 2,256 2,256 2,621 2,438 2,377 2,316 2,438 2,591 2,682 3,111 3,050 3,111 3,172 Capture 0.2 1.7 4.4 11.6 7.2 3.2 0.2 12.8 1.0 3.3 1.7 2.3 1.6 4.3 5.6 0.3 3.0 1.6 6.6 5.0 7.2 6.5 1.7 7.4 1.0 1.4 1.0 Middle FIt Esca1ant~ Middle FIt Escalant~ E FIt Escalante Esca1ant~ Escalant~ Gunnison Gunnison Gunnison Point Cit Point CIt Gunnison Dry Gulch Negro Dry Gulch Beebe Gulch Gunnison Gunnison Alkali Point W FItDoughspoon Oalt Sand Kiser Ward Dirty George Dirty George Dirty George Dirty George G G G G G G G G G G G G G G G G G G G G G G G G F G G F F G F G G G F G G G F F F F G F G F G F F F F F G G MALE PUMA 155 2- 5-88 2-12-88 2-19-88 2-26-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 4-88 6-10-88 6-17-88 6-30-88 7- 8-88 7-14-88 NIl SW SW SW NIl 2 49 13 736 4269 34 51 13 734 4280 3 50 13 734 4278 7 50 12 738 4277 30 12 50 4272 738 110 location - Momentary wealt signal NIl 23 50 13 4274 735 SE 19 50 12 740 4273 NIl 29 50 13 731 4272 SE 31 50 12 739 4270 NE 2 50 13 736 4269 SE 49 11 13 736 4267 NE 30 50 13 4272 730 SW 23 49 13 735 4263 SE 11 49 13 736 4266 NE 10 49 14 725 4267 SE 5 49 13 732 4268 33 NE 49 13 4261 733 SW 15 49 13 734 4264 NIl 27 49 4263 13 734 NE 11 49 14 727 4267 NIl 20 49 12 741 4264 2,073 Capture Little Monitor 2,073 10.8 Dry FIt Escalante 1,829 2.2 Dry FIt Escalante 1,951 4.5 Cottonwood 2,042 4.8 Monitor over Monitor and Potter drainages 2,164 3.6 Cottonwood 2,103 4.4 Potter 2,196 9.0 Dry FIt Escalante 2,134 8.8 Potter 2,225 2.8 Monitor 2,438 2.5 Monitor 2,073 8.5 Dry FItEscalante 2,377 10.9 Potter 2,286 3.6 Potter 2,377 11.5 E FIt Escalante 2,256 7.0 Cottonwood 2,499 7.2 Potter 2,499 4.0 Monitor 2,438 1.8 Potter 2,377 9.0 Dry FItEscalante 2,256 14.0 Moor~ G G G G G G G G G G F G F G G G G G G G G G F G F G G F G G G G F G G G G G G G FEMALE PUMA 156 3- 3-88 3- 4-88 3-12-88 3-18-88 3-25-88 4- 2-88 4- 8-88 4-15-88 5-14-88 5-20-88 5-27-88 6- 4-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 8-88 SE SW NIl NE NE SW NIl SE NE SW SE SW NE NIl SE NIl NIl 36 31 36 14 16 9 24 34 22 30 26 7 6 36 23 21 28 51 51 15 51 51 51 50 50 50 51 51 50 50 51 51 51 51 14 13 99 14 14 15 14 14 15 15 16 15 15 16 15 15 15 728 729 725 726 723 712 727 725 715 710 707 710 711 708 713 713 713 4280 4279 4287 4285 4284 4285 4274 4270 4274 4280 4280 4276 4279 4288 4282 4282 4281 1,859 2,103 2,134 2,134 2,316 2,530 2,196 2,196 2,530 2,530 2,621 2,682 2,560 2,714 2,377 2,347 2,134 Capture 1.5 8.4 2.5 6.6 10.2 18.5 9.1 10.5 9.0 2.6 5.5 3.0 3.4 11.4 4.8 2.3 Escalante Escalante Little Doalnguez Palmer Little Dominguez Keith Escalante E FIt Escalante Kelso Keith Big Dominguez N Fk Escalante Red Ck Keith Red Ck Keith Red Ck G G G G G F F F F F G F F G G F G G G G G G G G G G G F G G G F �225 Legal description Date -------1/4 T R S U.T.M. X Y Approx. elev (m) Distance (Itm) between locations Rating Major drainage Signal Locat Ior, FEMALE PUMA 157 4-15-88 4-22-88 4-29-88 5- 7-88 5-14-88 5-20-88 5-27-88 6- 4-88 6-10-88 6-17-88 6-23-88 6-30-88 7- 8-88 7-14-88 HE I,E I;W HE SW NW HE SW NW NW SE SW SW SW 23 20 14 14 30 26 26 26 7 7 28 5 20 28 50 50 50 50 SO 50 50 15 50 48 49 48 49 51 13 12 13 13 12 13 13 99 12 12 12 12 12 13 736 741 735 736 738 735 736 723 739 740 743 742 740 732 4274 4274 4275 4276 4272 4272 4272 4288 4278 4257 4262 4257 4263 4281 1,920 2,012 2,164 2,042 2,073 1,890 2,196 2,012 1,920 2,560 1,951 2,316 2,256 2,134 Capture 4.8 6.3 1.3 4.6 3.0 1.2 20.0 18.5 20.9 6.0 4.8 6.1 19.4 Cottonwood Potter Grade Gulch Cottonwood Monitor Cottonwood Cottonwood Little Doainguez Cottonwood Terrible Traver Long Moore Escalante G G G G G G G G G G G G G F G G F F F G F F G F G F ��227 Wildlife Research Report July 1988 JOB PROGRESS REPORT State of Colorado Project No. W-153-R-2 -----------------------No. 8A ---------------------- Work Plan Mammals Research Small Carnivorous Mammal Investigations Job No. 1 Period Covered: July 1, 1987 - June 30, 1988 Author: Development of River Otter Reintroduction Procedures T. D. I. Beck Personnel: S. Boyle, C. Haynes ABSTRACT Agreement was reached to trade for river otters with Oregon Department of Fish and Wildlife. Formal agreements between Colorado Division of Wildlife and BLM were completed. Fish surveys provided data on fish species distribution in the Dolores River but were inadequate to estimate fish biomass. Crawfish were widespread in distribution throughout the study area. River otter prey appears to be adequate for reintroduction. A detailed study plan was prepared, peer reviewed, and approved. ��229 DEVELOPMENT OF RIVER OTTER REINTRODUCTION PROCEDURES Thomas D. I. Beck P. N. OBJECTIVE Develop procedures for river otter reintroductions in Colorado and establish a self-sustaining population of river otters from which to collect river otters for future translocations. SEGMENT OBJECTIVES 1. Introduce up to 20 river otters into the Dolores River drainage. 2. Monitor all river otter release sites in Colorado to evaluate success of past reintroductions. 3. Develop techniques to monitor survival, reproduction, dispersal of river otters after reintroduction. dispersion, and METHODS AND MATERIALS Surveys of fish distribution were conducted unevenly along the 98-mi study stretch of the Dolores River. Hoop, seine, and gill nets were used to sample various habitats. Passive capture nets were set in late afternoon and pulled 12-16 hrs later. All captured fish were measured (cm) and weighed (gms) and some collected for reference collections. Crawfish were also collected and preserved in formalin. Nearly all sampling was canoe-based as road access is limited to a 10-mi stretch below Dove Creek Pump Station and 4 road crossings. Substantial time was devoted to revising the study plan and coaxing the Environmental Analysis Report (EAR) through the BLM channels. RESULTS AND DISCUSSION An approved study plan was completed in May, 1988 (Appendix A). The EAR was approved by the Colorado Division of Wildlife and the Colorado State Office of BLM in June, 1988. River otters were to be received fro~ the Oregon Department of Fish and Wildlife in late summer 1988. Procedures (surgeons, anesthesia, operating room) were completed for the surgical implantation of radio transmitters into the river otters. Crawfish samples (n ~ 15) were sent to Dr. Horton H. Hobbs, Jr. at the Smithsonian Institute for identification. The samples from the Dolores River were identified as "probably" Orconectes causeyi (H. H. Hobbs, Jr., pers. comm.). The 3 species of the Virilis Group (Q. nais, Q. causeyi, Q. virilis) of the subgenus Gremicambarus are nearly indistinguishable from morphological characters (Fitzpatrick 1987). It is unknown if crawfish were native to the �230 Dolores River, but it is known that the Colorado Division of Wildlife released crawfish (species and origin unknown) into the drainage in 1954 (Klein 1955). Pending more detailed studies of the Virilis Group, the crawfish of the Dolores River will be considered as o. causeyi. Crawfish were collected throughout the 98-mi study stretch of the Dolores River. Twenty-two nights of gill netting resulted in the capture of 172 round tail chubs (Gila robusta), 99 flannelmouth suckers (Catostomus latipinnis), 41 rainbow trout (Salmo gairdneri), 15 brown trout (Salmo trutta), 14 bluehead suckers (Catostomus discobolus), 13 channel catfish (Ictalurus punctatus), 3 green sunfish (Lepomis cyanellus), 1 carp (Cyprinus carpio), 1 mottled sculpin (Cottus bairdi), and 1 Snake River cutthroat (Salmo clarki). Gill netting was the most effective technique tried. The abundance of boulder-dominated river bottoms made all netting attempts relative inefficient. The deep, slow pools of Slickrock Canyon (RM 103-70) were poorly sampled, so samples of carp, channel catfish, and bullheads (Ictalurus spp.) were small. Flannelmouth suckers, bluehead suckers, and roundtail chubs were common throughout the study stretch (RM 166-69). Channel catfish and carp were found from RM 144.5 downstream to RM 69. Green sunfish were collected in a short stretch, RM 146-135. Crawfish were relatively abundant from RM 166 down to RM 129 and were present in apparently lower numbers down to RM 69. Rainbow trout were common from RM 167 to 148 with a few specimens down to RM 137.5. Brown trout were common throughout RM 167 to 135.6, with a single specimen caught down at R}l 112. All species caught appeared to be in good body condition. Ponderal indexes (KTL) (Carlander 1969) were calculated for each fish. Values for rainbow trout compared favorably to those of fish taken in the Dolores River immediately downstream of McPhee Dam [K = 1.15 (n = 37) study area vs. K = 1.12 (n = 47) catch and release area]. Comparisons of nongame species between rivers is limited by the lack of published data on suckers and roundtail chubs in the West. Reference collections of fish scales and selected bones were developed and a key to separate the Dolores River fishes using scales only was developed. Review of the literature on fish biomass estimation and our experience on the Dolores River in 1987 leads to the conclusion that reliable estimates of river otter prey base are unobtainable. We must resign ourselves to making general observations about the prey base which do not convey much information; e.g. there are at least 10 species of fish in the Dolores River which can attain a size of >10 cm and be considered potential river otter prey. Two river otters killed in beaver traps were collected during the year, a, female on the N. Fk. Gunnison and a male on the Fraser River (proximate'to Rocky MOuntain National Park release site). Based on studies of chese carcasses, an external radio transmitter package was developed. Utility of the new design will be tested on 2 river otters maintained in a large holding pen (2.5 x 5 m) for 30 days prior to release in the wild. The holding pens for 2 river otters and 12 transport cages were built. The transport cages measure 40 x 40 x 76 cm and are made of 5 x 5 cm framing covered with 0.6 cm thick pegboard (for ventilation) lined with 0.6 cm2 hardware cloth. The cages have waterproof bottoms of epoxy coating, a vertically sliding door, and a movable rear panel to force the animals out of the cage. The cages exceed the minimum requirements for live animal transport �231 as described in the lATA Live Animals Regulations issue date May, 1987). (Section 4, pages 29-30, A survey for river otter sign was conducted on the Gunnison River in January, 1988. Unusually cold weather had maintained a constant snow cover along the banks for over a month, extending to the confluence with the Colorado River. The survey began at the confluence of the Gunnison and N. Fk. Gunnison Rivers (RM 72.8) and ended at RM 36.5. Surveys were done from canoes and were ended when slush ice completely filled the river channel. Ambient temperature at sunrise varied from -26oC to -16oC. River otter sign (scat, tracks, fish remains) were seen regularly between RM 72.8 and RM 64.0. No river otter sign was observed between RM 64.0 and RM 36.5. Because of land use practices, the Gunnison River between RM 64.0 and 51.0 has little bank cover, and adequate cover for river otters appears to be lacking. LITERATURE CITED Carlander, K. D. 1969. Handbook of freshwater fishery biology. State Univ. Press, Ames. 752pp. Vol. I. Iowa Fitzpatrick, J. F., Jr. 1987. The Subgenera of the crawfish genus Orconectes (Decapoda: Cambaridae). Proc. BioI. Soc. Wash. 100(1):44-74. Klein, W. D. 1955. Rep. 1123. 4pp. Prepared by Crayfish Introductions. L ,PrJ4J.. Colo. Div. Wild1. Spec. Purpose ~T~h~o~m~a-s~D~.~I~.~B-e-c~k-------------Wildlife Researcher ��Colorado Division of Wildlife Wildlife Research Report July 1988 233 JOB PROGRESS REPORT State of Colorado Project No. W-l53-R-2 ------------------------- Work Plan No. Mammals Research 9A --~~----------------- Job No. 1 Elk Investigations Impact of Elk Winter Grazing on Livestock Production and Work Plan No. 3 ----------------------- Job No. 5 Period Covered: July 1, 1987 - June 30, 1988 Author: N. T. Hobbs, D. L. Baker Personnel: G. Bear, M. Miller, L. Carpenter, B. Gill, K. Navo, C. Woodward, B. Seely, H. Seely, L. Lovett ABSTRACT Elk grazing during winter influenced forage production and cattle performance on sagebrush-grassland range during spring. The magnitude of that influence depended on year for cattle responses, but was largely independent of year for vegetation responses. Elk grazing caused linear declines in daily gains and weights of heifers at the end of the spring grazing season during the first year of treatment. During year 2, we observed similar, proportional effects of treatment on rates of gain and weights of cows in late spring. During year 2, birth dates of calves whose mothers were in the high density elk treatment during year 1 averaged 6 days later than,calves whose mothers were in controls the previous year. During both years we observed linear declines in the standing crop of live and dead, perennial grass in relation to elk density. Utilization of dead perennial irass Lnceased in propor t Ion to treatment and approached 80% in the high density treatment during year 2. Utilization of live perennfa.l grass reached an asymptote at about 20% for the moderate and high density treatments during both years. Although we occasionally observed a weak stimulation of primary production of grasses and forbs by elk grazing, the overall influence on production was negligible. Large differences in precipitation between year land 2 caused marked reductions in forage production. The magnitude of these reductions did not depend on elk density. ��235 IMPACTS OF WINTER GRAZING BY ELK ON CATTLE PRODUCTION P. N. OBJECTIVES 1. To test the hypothesis that elk grazing during winter influences the productivity and botanical composition of herbage on sagebrush grassland ranges during spring. 2. To test the hypothesis that elk grazing during winter influences the body weights and rates of gain of cows and calves using sagebrush grassland ranges during spring. METHODS AND MATERIALS Study Area We conducted experiments on the Little Snake Wildlife Management Area in northwestern Colorado (township 9 north, range 95 west, sections 9, 10). The area is about 35 km (19 mi) north of Maybell, Colorado on County Road 19. Although this area does not typically contain high concentrations of elk during winter, it is representative of areas that do have those high densities. Topography of the area includes level ridge tops, rolling hills, and deep gullies, ranging in elevation from 1,800 to 2,000 m (5,900 to 6,600 ft). Aspects are southern and southwesterly with an average slope of 15 degrees. Soils are generally sandy and sandy loam. Climate of the area is dry and cold. The growing season averages only 81 days. Annual mean temperature is 6.06 C (42.9 F). Annual precipitation averages 27.5 cm (12.5 in). Vegetation is dominated by big sagebrush (Artemisia tridentata) with an understory predominated by needle and thread (Stipa comata), western wheatgrass (Agropyron smithii), Indian ricegrass (Oryzopis hymenoides), Junegrass (Koleria cristata), and cheatgrass (Bromus tectorum). Important forbs include wallflower (Erysimum asperum), peppergrass (Lepidium perfoliatum), silver lupine (Lupinus argenteus), and scarlet globe mallow (Sphaeralcea coccinea). Experimental Design We observed effects of elk grazing on forage and cattle response in a randomized complete block design with four levels of elk density (0 elk/km2, 8 elk/km2, 15 elk/km2, and 30 elk/km2) and three replications per level. There were three blocks, each consisting of four pastures. Each pasture within a block was stocked with one level of elk density such that each block contained all levels. During year 1, the twelve available pastures were blocked by pretreatmet biomass of perennial grasses with the four lowest grass biomass pastures forming one block, and the four highest grass biomass pastures forming a second block, and the remaining four pastures serving as the third block. The four levels of elk density were randomly assigned to pastures within each block during year 1. �236 Procedures We stocked pastures with elk in December and January 1987-88. Average date of release into pastures was January 3. All elk were removed from pastures during April 18-21. Overwinter mortality approached 30% in the high density pastures, but was nil in the medium and low density ones. Replacement animals were substituted for those that died to maintain a consistent stocking rate across replications. We introduced 7 cow-calf pairs and one dry heifer into each pasture on May 9. With the exception of the heifers and few replacements required by death losses, etc., cows during year 2 were the same animals we observed during year 1 and were assigned to the same pastures they were in previously. Cows and calves were weighed to the nearest 0.5 kg when they were introduced to pastures and were reweighed 6 weeks later when they were removed. Animals were allowed free access to feed and water before weighing. We also observed the birth dates of all calves and weighed them to the nearest 0.5 kg immediately after birth. We estimated canopy cover of herbs shrubs immediately after removing cattle from pastures. Cover was estimated from the summed length of interception by each plant along 30, l2-m transects randomly placed in each pasture during year 1. We estimated standing crop, productivity, and utilization of forbs, perennial grass, and annual grasses by harvesting samples from 40 pairs of 1/4 m2 plots in each pasture on each of three sample dates. Pastures were sampled immediately after the elk were removed (April 27-29), at the midpoint of the spring grazing season (May 30-June 1), and at its end (June 30-July 2). Samples were dried at 600C for 48 hrs, separated by hand into live and dead, and weighed to the nearest 0.01 g. RESULTS All results described in this report are preliminary and are subject to revision as analyses are checked for accuracy. Here, we report our findings to provide a timely summary of progress, but we are obliged to thoroughly revisit them later. This is particularly the case for data on forage production, which are based on pooled estimates from composites of material harvested from individual plots. We have not yet been able to check and summarize data for individual plots from year 2. This process will probably modify our results. . Effects of Elk on Cattle Performance Elk grazing during winter influenced the performance of cattle during spring, and the magnitude of that influence depended on year (Table 1). Weights of adult cows (defined as animals 2 yrs or older with calves) at the end of the grazing season during year 2 declined in direct proportion to elk density (Fig. 1 linear effect P=0.03, Table 1). This decline in weights resulted from the effects of treatment on cow rates of gain (Fig. 2, linear effect p=0.045). We observed no such effects during the first year (linear effect P > 0.28). �237 Average weights of cows at the end of the grazing season were lower during the second year than the first (Fig 1. P-O.OOl), and the difference between years was greatest in the high density pastures (Year x level P=O.OOl). The effect of year on average daily gain of cows only approached significance (P=0.09). The coefficient of variation (CV) for cow weights into pastures was 3.1%, for weights out of pastures was 3.4%, and for average daily gain was 27%. Because CV's on weights were small, the large variability in average daily gain resulted in large part from variability induced by treatment. Although we saw linear declines in weights out of pastures and rates of gain of heifers (defined as 1 year old cows without calves) in response to elk density during the first year (Fig 3., Fig. 4, Table 1, linear effect P < 0.05), we were unable to detect any effect of treatment during year 2 (p > 0.48). Heifers weighed more at the end of the grazing season during year 2 than year 1 (Fig. 3, P=O.06) as a result of more rapid rates of gain (Fig. 4, P=0.05). Using analysis of covariance to remove the effect of heifer weights at the beginning of the grazing season did not change effects of treatment or year. Calves during year 2 whose mothers were in the high density treatment during year 1 were born an average of 6 days later than calves whose mothers were in the control (P=O.07, Table 1), and birth dates were generally delayed in proportion to elk density (linear effect P=O.lO). During both years, birth weights of calves tended to decline relative to elk density. However, this tendency resulted at least in part from a spurious effect of the initial randomization. On average, larger calves were assigned to the control and low density pastures than to the medium and high ones (Fig. 5) These assignments resulted purely by chance. That is, there was no opportunity for treatment to affect birth weights of calves during year 1. The effect of these assignments persisted when calves were weighed into and out of pastures (Figs. 6, 7, 8). When we removed the effect of birth weight from later weights using analysis of covariance, treatment effects on weights out of pasture and average daily gain were not significant during either year (p > 0.23). MOreover, we saw no significant (P=O.13) linear trend in weights out the pastures or daily gain (P=O.23) during year 2 even when the effects of birth weights were included in the analysis. Effects of Elk on Vegetation Elk grazing reduced the standing crop of live (Fig. 9, P-0.13) and dead perennial grass at the beginning of the grazing season (Fig. 10, P=0.03) during both years (Table 2). The effect of treatment did not depend on y.ear for either response (p > '0.45). Effects of treatment on live and dead forbs and dead annual grass were also consistent between years (Figs. 11, 12, 1.3, treatment x year interaction P >0.67). Elk grazing at the highest density tended to reduce the standing crop of dead forbs available to cattle during year 2 (Fig. 11, control v~3l elk/km2 P=0.13). Otherwise, we observed no effects on live or dead forbs. We consistently observed a significant quadratic effect on the standing crop of dead annual grass (Fig. 13, quadratic P=O.04, year x quadratic P=0.63), but could detect no treatment effects on the standing crop of live annual grass (Fig. 14, P > 0.29). Standing crops of all forage classes except dead forbs were lower during year 2 than during the previous year. �238 Effects of elk grazing on standing crops of perennial live and dead perennial grasses resulted from differences in rates of utilization during winter. During both years we observed highly significant linear relationships between elk density and utilization of standing dead perennial grass (Fig. 15, linear effect P=O.OOOl, year x linear effect P=0.35). Although rates of utilization during year 2 appeared to be less intense those during year one, this appearance was influenced by negative utilization values in the control. Negative values are artifacts of field methods. If values are adjusted such that the control utilization rates = 0.0 for both years, utilization for year 2 exceeds that for year 1 by about 15 percentage points. During both years, utilization of live perennial grass increased between controls and the medium elk density (Fig. 16, linear effect P~ 0.07, year x linear effect P=0.98). We observed no difference in utilization of live perennial grass between the medium and high densities during either year (P>O.78). Values for primary production of all forage classes during year 2 exceeded values for year 1 (Figs. 17, 18, 19, Year effect P < 0.005). In general, we could not detect any effect of treatment on primary production of perennial grass, annual grass, or forbs before May 1 (Figs. 17,18, 19, Table 2). However, during year two, forb production before May 1 in the 15 elk /km2 treatment tended to exceed control values (P=0.08, Fig. 19, Table 2) and this led to a quadratic effect that approached significance (P=0.15). During May I-May 30 of year 1, forb production in the 8 elk/km2 treatment tended to exceed control values (Fig. 20, P=0.15, Table 2), and we also observed a weak stimulation production of perennial grass by moderate and light elk grazing (Fig. 21, quadratic effect P=0.09, Table 2). Otherwise, we could detect no effect of treatment on primary production during May 1-30 (Figs. 20, 21, 22, Table 2). DISCUSSION Differences in weather contributed to year effects. Winter weather during year 2 was far more severe than during the first year. Crusted snow covered most of the herbaceous forage during January to March and this coverage probably reduced the level of utilization of grasses and forbs by elk that we would have observed in the absence of snow accumulation. Although snowfall was heavier during year 2, precipitation during the growing season was substantially reduced. Rainfall during year 2 was half that of year 1, and this difference was reflected in rates of primary production. A confounding influence emerged in our measurements of cattle performance. Our cooperator decided to breed his cows to both Hereford and Angus bullsdu~ing year 2. This resulted in a mixture of Herefords and Angus/Hereford crosses within pastures. Fortunately, this mixture was balanced across treatments with the exception of the 15 elk/km2 level, which tended to have more crossbred calves. In the future we will do our best to assure that the experiment is balanced for breed. At the end of two years of study we have observed significant effects of elk density on cow weights, but not on weights of calves. This is not unexpected because the performance of calves is buffered from environmental influences by the milk they receive from their mothers. However, we did observe that increasing elk density delayed birth dates of calves. If this delay increases �239 during succeeding years, then we anticipate that elk density will eventually compel reductions in calf weights in and out of pastures as a consequence of differences in calf age. Prepared WCWt £8k Dan L. Baker Wildlife Researcher C N. Thompson Hobbs Wildlife Researcher C �240 Table 1. Contrasts testing for differences between the control and treatment levels for cattle responses to elk density. Response/contrast OF Contrast SS Mean Square F Value Pr F Cow Weight Into Pasture (kg) Year 1 control vs others control vs 8 elk/km2 control vs 15 e1k/km2 control vs 31 e1k/km2 1inear effects quadratic effects 1 1 1 1 1 1 53.413091 0.010280 26.601413 159.842136 201.075503 6.029824 53.413091 0.010280 26.601413 159:.842136 20L075503 6.029824 0.17 0.00 0.08 0.50 0.63 0.02 0.6970 0.9957 0.7828 0.5062 0.4581 0.8953 Year 2 control vs others control vs 8 elk/km2 control vs15elk/km2 control vs 31 elk/km2 linear effects quadratic effects 1 1 1 1 1 1 184.227639 97.854023 125.174601 148.030479 118.333249 60.476155 184.227639 97.854023 125.174601 148.030479 118.333249 60.476155 1.16 0.61 0.79 0.93 0.74 0.38 0.3236 0.4631 0.4096 0.3724 0.4219 0.5605 Cow Weight Out of Pasture (kg) Year 1 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 linear effects quadratic effects 1 1 1 1 1 1 7.113415 268.050598 95.255095 0.006296 50.729412 1.930841 7.113415 268.050598 95.255095 0.006296 50.729412 1.930841 0.02 0.92 0.33 0.00 0.17 0.01 0.8809 0.3742 0.5880 0.9964 0.6908 0.9377 Year 2 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 1inear effects quadratic effects 1 1 1 1 1 1 1799.89964 774.22459 828.12000 2239.01067 1968.06072 142.97798 1799.89964 774.22459 828.12000 2239.01067 1968.06072 142.97798 7.23 3.11 3.33 9.00 7.91 0.57 0.0361 0.1282 0.1179 0 •.0240 0.0307 0.4771 0.00065118 0.01259802 0.10833942 0.02383994 0.00748295 0.11349828 0.00065118 0.01259802 0.10833942 0.02383994 0.00748295 0.11349828 0.00 0.08 0.67 0.15 0.05 0.70 0.9514 0.7893 0.4438 0.7139 0.8366 0.4337 Cow Gain in Pasture (k9/d) Year 1 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 1inear effects quadratic effects 1 1 1 1 1 1 �241 Tab 1e 1. Cont. Response/contrast OF Contrast SS Mean Square F Value Pr 0.47190932 0.18230404 0.17538005 0.70046568 0.63561598 0.00990830 0.47190932 0.18230404 0.17538005 0.70046568 0.63561598 0.00990830 4.70 1.82 1.75 6.98 6.33 0.10 0.0733 0.2265 0.2345 0.0385 0.0455 0.7641 F Cow Gain in Pasture (k~/d) Year 2 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 linear effects quadratic effects 1 1 1 1 1 1 Heifer Weight Into Pasture (kg) Year 1 control vs others control vs 8 elk/km2 control vs 15 elk /km2 control vs 31 elk/km2 1inear effects quadratic effects 1 1 1 1 1 1 10.163503 224.906289 134.514711 92.691145 299.063614 0.009916 10.163503 224.906289 134.514711 92.691145 299.063614 0.009916 0.03 0.61 0.36 0.25 0.81 0.00 0.8750 0.4713 0.5732 0.6383 0.4103 0.9961 Year 2 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 e1k/km2 linear effects quadratic effects 1 1 1 1 1 1 233.417170 99.958351 766.495899 271.526096 628.596732 180.883030 233.417170 99.958351 766.495899 271.526096 628.596732 180.883030 0.28 0.12 0.92 0.33 0.76 0.22 0.6190 0.7430 0.3812 0.5925 0.4244 0.6606 Heifer Weight Out of Pasture (kg) Year 1 control vs others control vs 8 e1k/km2 control vs 15 e1k/km2 control vs 31 e1k/km2 1inear effects quadratic effects Year 2 control vs others control vs 8 e1k/km2 control vs 15 elk/km2 control vs 31 elk/km2 linear effects quadratic effects 1 1 1 1 1 1 477.173149 652.814414 552.890342 19.744859 2.468597 933.421845 477.173149 652.814414 552.890342 19.744859 2.468597 933.421845 0.58 0.79 0.67 0.02 0.00 1.13 0.4761 0.4083 0.4446 0.8822 0.9582 0.3288 1 1 1 14.283029 6.718737 0.137117 131.769513 177.470636 54.535202 14.283029 6.718737 0.137117 131.769513 177.470636 54.535202 0.01 0.01 0.00 0.11 0.15 0.05 0.9149 0.9416 0.9916 0.7466 0.7081 0.8349 1 1 1 �242 Table 1. Cont. Response/contrast Contrast SS Mean Square F Value 1 1 1 1 1 1 0.10939538 0.07322377 0.03029204 0.13017558 0.09882086 0.00798611 0.10939538 0.07322377 0.03029204 0.13017558 0.09882086 0.00798611 6.56 4.39 1.82 7.81 5.93 0.48 0.0505 0.0902 0.2355 0.0382 0.0590 0.5197 1 1 1 1 1 1 0.01803490 0.03109231 0.11718076 0.01416643 0.05661465 0.03524869 0.01803490 0.03109231 0.11718076 0.01416643 0.05661465 0.03524869 0.18 0.31 1.16 0.14 0.56 0.35 0.6897 0.6024 0.3300 0.7230 0.4871 0.5798 1 1 1 1 1 1 0.1111111 8.1666667 1.5000000 6.0000000 14.4857143 2.5021645 0.1111111 8.1666667 1.5000000 6.0000000 14.4857143 2.5021645 0.02 1.14 0.21 0.83 2.01 0.35 0.9051 0.3275 0.6639 0.3962 0.2056 0.5768 1 1 1 1 .1 1 53.5452255 23.9048564 40.5352419 44.4629630 38.2010582 17.9242424 53.5452255 23.9048564 40.5352419 44.4629630 38.2010582 17.9242424 5.37 2.40 4.07 4.46 3.83 1.80 0.0597 0.1725 0.0904 0.0792 0.0980 0.2285 1 1 1 1 1 1 9.3578780 4.0265907 1.8530518 17.0176295 15.0600917 0.0379540 9.3578780 4.0265907 1.8530518 17.0176295 15.0600917 0.0379540 2.30 0.99 0.45 4.18 3.70 0.01 0.1804 0.3585 0.5251 0.0869 0.1028 0.9262 OF Pr F Heifer Gain in Pasture (kg/d) Year 1 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 e1k/km2 1inear effects quadratic effects Year 2 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 1inear effects quadratic effects Cal f Birth Date Year 1 control vs others control vs 8 elk/km2 control vs 15 elk /km2 control vs 31 elk/km2 1inear effects quadratic effects Year 2 control vs others control vs 8 elk/km2 control vs 15 e1k/km2 control vs 31 elk/km2 linear effects quadratic effects Calf Birth Weight (kg) Year 1 control vs others control vs 8 elk/km2 control vs 15 e1k/km2 control vs 31 elk/km2 linear effects quadratic effects �243 Tab1e 1. Cont. Response/contrast OF Contrast SS Mean Square F Value 1 1 1 1 1 1 3.23735720 0.11659716 1.40784233 8.29033618 9.71352236 0.16260247 3.23735720 0.11659716 1.40784233 8.29033618 9.11352236 0.16260247 1.60 0.06 0.69 4.09 4.79 0.08 0.2534 0.8185 0.4368 0.0897 0.0713 0.7866 Pr F Calf Birth Weight Year 2 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 linear effects quadratic effects Calf Weight Into Pasture (kg) Year 1 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 linear effects quadratic effects 1 1 1 1 1 1 11.3499362 0.7163668 23.9430206 17.6860045 29.2917260 2.8187408 11.3499362 0.7163668 23.9430206 17.6860045 29.2917260 2.8187408 1.11 0.07 2.35 1.73 2.87 0.28 0.3320 0.7998 0.1763 0.2359 0.1410 0.6179 Year 2 control vs others control vs 8 e1k/km2 control vs 15 elk /km2 control vs 31 elk/km2 1inear effects quadratic effects 1 1 1 1 1 1 39.4916543 9.6612743 18.4466873 63.8394316 63.8986943 0.6081260 39.4916543 9.6612743 18.4466873 63.8394316 .63.8986943 0.6081260 3.83 0.94 1.79 6.20 6.20 0.06 0.0980 0.3703 0.2294 0.0472 0.0472 0.8162 1 1 1 1 1 1 63.285596 . 1.454672 54.690238 118.480129 147.873890 1.187521 63.285596 1.454672 54.690238 118.480129 147.873890 1.187521 2.13 0.05 1.84 3.98 4.97 0.04 0.1950 0.8323 0.2240 0.0930 0.0673 0.8483 1 1 1 1 100.916318 64.652102 21.261620 142.926366 110.844169 1.117207 100.916318 64.652102 21.261620 142.926366 110.844169 1.117207 2.82 1.81 0.59 4.00 3.10 0.03 0.1439 0.2272 0.4698 0.0925 0.1287 0.8655 Calf Weight Out of Pasture (kg) Year 1 control vs others control vs 8 elk/km2 control vs 15 elk /km~ control vs 31 elk/km~ 1inear effects quadratic effects Year 2 control vs others control vs 8 elk/km2 control vs15e1k/km2 control vs 31 elk/km2 linear effects quadratic effects 1 1 �244 Tab1e 1. Cont. Response/contrast OF Contrast SS Mean Square F Value Pr F 1 1 1 1 1 1 0.00518067 0.00110539 0.01122251 0.00137811 0.00165435 0.00820535 0.00518067 0.00110539 0.01122251 0.00137811 0.1)0165435 0.00820535 0.77 0.16 1.66 0.20 0.24 1.21 0.4150 0.7000 0.2450 0.6675 0.6384 0.3128 1 1 1 1 1 1 0.00403162 0.01097058 0.00211109 0.00002346 0.00072119 0.00754712 0.00403162 0.01097058 0.002111 09 0.00002346 0.00072119 0.00754712 0.40 1.08 0.21 0.00 0.07 0.74 0.5516 0.3384 0.6643 0.9632 0.7987 0.4215 1 1 1 1 1 1 0.00793583 0.00045334 0.00105839 0.02702202 0.02995751 0.00294858 0.00793583 0.00045334 0.00105839 0.02702202 0.02995751 0.00294858 1.11 0.06 0.15 3.78 4.19 0.41 0.3327 0.8096 0.7137 0.0999 0.0866 0.5445 1 1 1 1 1 1 0.01231732 0.01072953 0.00165587 0.01627587 0.01101600 0.00013509 0.01231732 0.01072953 0.00165587 0.01627587 0.01101600 0.00013509 2.01 1.75 0.27 2.65 0.2063 0.2342 0•.6220 0.1545 0.2288 0.8869 Calf Gain: Birth-May (kg/d) Year 1 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 linear effects quadratic effects Year 2 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 linear effects quadratic effects Calf Gain in Pastures (kg/d) Year 1 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 1inear effects quadratic effects Year 2 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 1inear effects quadratic effects 1.80 0.02 �245 Table 2. Contrasts testing for differences between control and treatment levels for vegetation responses. Response/Contrast OF Contrast SS Mean Square F Value Standing Cro~, Dead Annual Grass, May 1 (g/m2) Year 1 control vs others 1 0.47129494 0.47129494 control vs 8 elk/km2 1 0.30943434 0.30943434 control vs 15 elk/km2 0.58847048 0.58847048 1 control vs 31 elk/km2 0.12831499 0.12831499 1 linear effects 1 0.07703806 0.07703806 quadratic effects 1 0.56074783 0.56074783 3.54 2.32 4.42 0.96 0.58 4.21 0.1091 0.1784 0.0803 0.3644 0.4759 0.0861 2.98 2.45 4.78 0.23 0.04 5.93 0.1353 0.1688 0.0714 0.6516 0.8396 0.0508 0.72 0.21 0.70 0.61 0.60 0.28 0.4297 0.6645 0.4348 0.4644 0.4667 0.6181 Pr F Year 2 control vs others control vs 8 elk/km2 control v s 15 elk /km2 control vs 31 elk/km2 linear effects quadratic effects 1 1 1 1 1 1 0.16496547 0.13565296 0.26496534 0.01250473 0.00247503 0.32885805 0.16496547 0.13565296 0.26496534 0.01250473 0.00247503 0.32885805 Standing Cro~, Live Annual Grass, May 1 (g/m2) Year 1 control vs others 0.32469754 0.32469754 1 control vs 8 elK/km2 1 0.09412864 0.09412864 control vs 15 elk /km2 0.31714935 0.31714935 1 control vs 31 e1k/km2 0.27647616 0.27647616 1 0.27344231 1inear effects 1 0.27344231 quadratic effects 0.12508288 0.12508288 1 Year 2 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 1inear effects quadratic effects 0.00033478 0.00080655 0.00001969 0.00043498 0.00013739 0.00000890 0.00033478 0.00080655 0.00001969 0.00043498 0.00013739 0.00000890 0.56 1.35 0.03 0.73 0.23 0.01 0.4832 0.2902 0.8622 0.4271 0.6491 0.9070 Standing Cro~, Dead Forbs, May 1 (g/m2) Year 1 control vs others 0.00164312 1 0.01543621 control vs 8 e1k/km2 1 0.00014597 control vs 15 elk /km2 1 0.00286577 control vs 31 elk/km2 1 1 0.01109843 1inear effects quadratic effects 1 0.01069027 0.04787047 control vs others 1 0.00164312 0.01543621 0.00014597 0.00286577 0.01109843 0.01 069027 0.04787047 0.06 0.61 0.01 0.11 0.44 0.42 1.17 0.8096 0.4715 0.9426 0.7509 0.5383 0.5456 0.3295 1 1 1 1 1 1 �246 Table 2. Cont. Response/Contrast DF Contrast SS Mean Square F Value 0.03899230 0.00070888 0.12196144 0.08104926 0.01331676 0.95 0.02 2.97 1.97 0.32 0.3745 0.9006 0.1454 0.2190 0.5936 Pr F Standing CroE, Dead Forbs, May 1 <g/m2) Year 2 control vs 8 e1k/km2 control vs 15 elk /km2 control vs 31 e1k/km2 1 i near effects quadratic effects 1 1 1 1 1 0.03899230 0.00070888 0.12196144 0.08104926 0.01331676 Standing CroE, Dead Perennial Grass, Mall <9/m2) Year 1 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 1inear effects quadratic effects control vs others 1 1 1 1 1 1 1 66.630425 1.984317 47.229185 137.207396 166.839643 0.054346 39.0738233 66.630425 1.984317 47.229185 137.207396 166.839643 0.054346 39.0738233 3.01 0.09 2.13 6.19 7.53 0.00 1.90 0.1336 0.7748 0.1946 0.0473 0.0336 0.9621 0.2174 1 1 1 1 1 12.1342352 5.1821243 91.2345670 86.4497340 3.1659021 12.1342352 5.1821243 91.2345670 86.4497340 3.1659021 0.59 0.25 4.43 4.20 0.15 0.4717 0.6337 0.0799 0.0863 0.7084 Year 2 control vs 8 e1k/km2 control vs 15 elk/km2 control vs 31 e1k/km2 1inear effects quadratic effects Standing CroE, Live Perennial Grass, May 1 <g/m2) Year 1 control vs others control vs 8 elk/km2 . control ys15elk/km 2 control vs 31 e1k/km2 linear effects quadratic effects 1 1 1 1 1 1 11.6388369 4.5603544 4.4460805 16.9130156 15.2895613 0.3052176 11.6388369 4.5603544 4.4460805 16.9130156 15.2895613 0.3052176 3.66 1.43 1.40 5.32 4.81 0.10 0.1042 0.2761 0.2816 0.0605 0.0708 0.7671 1 1 1 1 1 1 1.45132601 0.61690690 0.35887224 2.45370589 2.17558971 0.00013527 1.45132601 0.61690690 0.35887224 2.45370589 2.17558971 0.00013527 0.53 0.23 0.13 0.90 0.80 0.00 0.4931 0.6511 0.7292 0.3794 0.4061 0.9946 Year2 control vs others control vs 8 e1k/km2 control vs 15 e1k/km2 control vs 31 e1k/km2 linear effects quadratic effects �247 Table 2. Cont. Response/Contrast OF Utilization by Elk, Dead Year 1 control vs others control vs 8 e1k/km2 control vs 15elk/km2 control vs 31 elk/km2 linear effects quadratic effects Year 2 control vs others control vs 8 e1k/km2 control vs 15e1k/km2 control vs 31 elk/km2 1inear effects quadratic effects Contrast SS Mean Square F Value Pr F Annual Grass (%) 1 1 1 1 1 1 17681.2165 19327.4114 7702.0705 9786.3438 4496.4282 7571.6199 17681.2165 19327.4114 7702.0705 9786.3438 4496.4282 7571.6199 3.25 3.55 1.42 1.80 0.83 1.39 0.1214 0.1084 0.2790 0.2283 0.3983 0.2827 1 1 1 1 1 1 111283.252 1881.937 65687.808 267755.739 326844.691 1714.683 111283.252 1881.937 65687.808 267755.739 326844.691 1714.683 0.80 0.01 0.47 1.92 2.34 0.01 0.4067 0.9114 0.5187 0.2157 0.1771 0.9154 Utilization by Elk, Live Annual Grass (%) Year 1 control vs others control vs 8 elk/km2 control vs 15e1k/km2 control vs 31 elk/km2 1inear effects quadratic effects 1 1 1 1 1 1 594.70031 1305.19823 123.58818 946.90596 271.10804 70.02368 594.70031 1305. 19823 123.58818 946.90596 271.10804 70.02368 0.33 0.72 0.07 0.53 0.15 0.04 0.5904 0.4334 0.8038 0.5009 0.7140 0.8514 Year 2 control vs others control vs 8 elk/km2 control vs 15elk/km2 control vs 31 elk/km2 linear effects quadratic effects 1 1 1 1 1 1 2998.81464 918.75391 1787.84014 3663.91965 3183.25371 374.56788 2998.81464 918.75391 1787.84014 3663.91965 3183.25371 374.56788 1.06 0.32 0.63 1.29 1.12 0.13 0.3511 0.5940 0.4634 0.3074 0.3380 0.7312 45.50647 1494.09141 8606.41961 2080.30270 376.27049 7312.36452 0.01 0.26 1.48 0.36 0.06 1.25 0.9339 0.6394 0.2912 0.5825 0.8120 0.3255 Utilization b~ Elk, Dead Year 1 control vs others control vs 8 elk/km2 control vs 15elk/km2 control vs 31 elk/km2 1inear effects quadratic effects Forbs (%) 1 1 1 1 1 1 45.50647 1494.09141 8606.41961 2080.30270 376.27049 7312.36452 �248 Table 2. Cont. Response/Contrast OF Contrast SS Mean Square F Value Pr F 1744.8801 4670l.4050 4706.9936 3898.5673 26949.6347 4047.1604 0.15 3.91 0.39 0.33 2.26 0.34 0.7217 0.1191 0.5641 0.5982 0.2074 0.5916 Utilization bl Elk, Dead Forbs (tt) Year 2 control vs others control vs 8 e1k/km2 control vs 15e1k/km2 control vs 31 e1k/km2 linear effects quadratic effects 1 1 1 1 1 1 1744.8801 46701.4050 4706.9936 3898.5673 26949.6347 4047.1604 Utilization by Elk, Live Forbs (tt) Year 1 control vs others control vs 8 elk/km2 control vs 15e1k/km2 control vs 31 e1k/km2 1inear effects quadratic effects 1 1 1 1 1 1 1604.21647 3414.11249 4.49406 2008.33744 723.57430 1.00352 1604.21647 3414.11249 4.49406 2008.33744 723.57430 1.00352 3.06 6.52 0.01 3.84 l.38 0.00 0.1404 0.0510 0.9298 0.1075 0.2926 0.9668 Year 2 control vs others control vs 8 elk/km2 control vs 15e1k/km2 control vs 31 e1k/km2 1inear effects quadratic effects 1 1 1 1 1 1 751.85970 100.03421 1397.63184 250.76455 344.60546 953.32716 751.85970 100.03421 1397.63184 250.76455 344.60546 953.32716 0.72 0.10 l.34 0.24 0.33 0.91 0.4348 0.7694 0.2995 0.6448 0.5905 0.3832 Utilization by Elk, Dead Perennial Grass (tt) Year 1 control vs others control vs 8 elk/km2 control vs 1Se1k/km2 control vs 31 elk/Km2 1inear effects quadratic effects 1 1 1 1 1 1 703.303989 169.003609 627.390022 724.270722 744.309184 180.283581 703.303989 169.003609 627.390022 724.270722 744.309184 180.283581 5.05 1.21 4.51 5.20 5.35 1.29 0.0657 0.3128 0.0780 0.0627 0.0601 0.2986 1 1 1 1 1 1 3250.78443 1072.52751 595.27664 6808.14667 6389.01475 96.88756 3250.78443 1072.52751 595.27664 6808.14667 6389.01475 96.88756 10.99 3.63 2.01 23.02 21.60 0.33 0.0161 0.1055 0.2058 0.0030 0.0035 0.5879 Year 2 control vs others control vs 8 e1k/km2 control vs 15e1k/km2 control vs 31 e1k/km2 1inear effects quadratic effects �249 Table 2. Cont. Response/Contrast DF Contrast SS Mean Square F Value Pr F Utilization by Elk, Live Perennial Grass (~) Year 1 control vs others control vs 8 e1k/km2 control vs 15e1k/km2 control vs 31 elk/km2 linear effects quadratic effects 1 1 1 1 1 1 703.303989 169.003609 627.390022 724.270722 744.309184 180.283581 703.303989 169.003609 627.390022 724.270722 744.309184 180.283581 5.05 1.21 4.51 5.20 5.35 1.29 0.0657 0.3128 0.0780 0.0627 0.0601 0.2986 Year 2 control vs others control vs 8 e1k/km2 control vs 15e1k/km2 control vs 31 e1k/km2 linear effects quadratic effects 1 1 1 1 1 1 675.906321 113.824158 706.497634 698.727628 772.063497 196.954482 675.906321 113.824158 706.497634 698.727628 772.063497 196.954482 1.79 0.30 1.87 1.85 2.04 0.52 0.2299 0.6032 0.2208 0.2231 0.2031 0.4978 Primary Production Before May 1, Annual Grass (~/m2) Year 1 control vs others control vs 8 e1k/km2 control vs 15 elk/km2 control vs 31 elk/km2 1inear effects quadratic effects 1 1 1 1 1 1 1.63474990 0.79878348 1.85937607 0.76477842 0.61345324 1.32772458 1.63474990 0.79878348 1.85937607 0.76477842 0.61345324 1.32772458 1.27 0.62 1.44 0.59 0.48 1.03 0.3029 0.4609 0.2748 0.4702 0.5159 0.3491 Year 2 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 1inear effects quadratic effects 1 1 1 1 1 1 0.00813918 0.00710854 0.00332782 0.00623897 0.00379828 0.00211770 0.00813918 0.00710854 0.00332782 0.00623897 0.00379828 0.00211770 1.62 1.42 0.66 1.24 0.76 0.42 0.2498 0.2788 0.4465 0.3074 0.4177 0.5399 0.82229708 0.57647929 0.06021183 1.48003922 1.13582494 0.01522518 0.46 0.33 0.03 0.83 0.64 0.01 0.5213 0.5893 0.8599 0.3962 0.4541 0.9292 Primarl Production Before May 1, Forbs (9/m2) Year 1 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 1inear effects quadratic effects 1 1 1 1 1 1 0.82229708 0.57647929 0.06021183 1.48003922 1.13582494 0.01522518 �250 Table 2. Cont. Response/Contrast OF Contrast SS Mean Square F Value Pr F Primar~ Production Before May 1, Forbs (9/m2) Year 2 control vs others 1 0.99457260 0.99457260 control vs 8 e1k/km2 0.00868384 0.00868384 1 control vs 15 e1k/km2 4.57474795 4.57474795 1 control vs 31 elk/km2 0.15773177 0.15773177 1 linear effects 0.51305536 1 0.51305536 quadratic effects 2."82640924 2.82640924 1 0.94 0.01 4.34 0.15 0.49 2.68 0.3687 0.9306 0.0823 0.7121 0.5114 0.1525 Primary Production Before May 1, Perennial Grass (9/m2) Year 1 control vs others 1.00640940 1.00640940 1 control vs 8 e1k/km2 1 1.47080961 1.47080961 control vs 15 e1k/km2 1.49935759 1.49935759 1 control vs 31 elk/km2 1 6.09615984 6.09615984 4.30457156 4.30457156 1inear effects 1 quadratic effects 1 3.88238390 3.88238390 0.13 0.19 0.19 0.79 0.56 0.50 0.7307 0.6781 0.6752 0.4089 0.4839 0.5053 Year2 control vs others control vs 8 e1k/km2 control vs 15 elk/km2 control vs 31 elk/km2 1inear effects quadratic effects 0.00201849 0.20890438 0.49781410 0.12855703 0.01889927 0.40857930 0.00 0.14 0.34 0.09 0.01 0.28 0.9716 0.7188 0.5813 0.7771 0.9133 0.6165 Primary Production Ma~ 1-30 (9/m2), Annual Grass Year 1 control vs others 1 0.22959601 0.22959601 control vs 8 elk/km2 1 0.18318803 0.18318803 control vs 15 e1k/km2 0.52763668 0.52763668 1 control vs 31 elk/km2 0.76618604 0.76618604 1 1.39683114 1.39683114 1 linear effects 1 0.00100032 0.00100032 quadratic effects 0.01 0.01 0.03 0.04 0.08 0.00 0.9148 0.9239 0.8713 0.8453 0.7925 0.9944 Year 2 control vs others control vs 8 e1k/km2 control vs 15 elk/km2 control vs 31 elk/km2 1inear effects quadratic effects 0.68 0.68 0.21 0.55 0.31 0.13 0.4412 0.4416 0.6664 0.4856 0.5971 0.7274 1 1 1 1 1 1 1 1 1 1 1 1 0.00201849 0.20890438 0.49781410 0.12855703 0.01889927 0.40857930 0.85931557 0.85766560 0.25951166 0.69744880 0.39334837 0.16869738 0.85931557 0.85766560 0.25951166 0.69744880 0.39334837 0.16869738 �251 Table 2. Cont. Response/Contrast OF Contrast SS Mean Square F Value Pr F Primary Production Mal 1-30, Forbs (9/m2) Year 1 control vs others control vs 8 e1k/km2 control vs 15 e1k/km2 control vs 31 elk/km2 1inear effects quadratic effects 1 1 1 1 1 1 6.7629642 24.0068970 0.2103269 1.0236826 0.3766138 4.3059728 6.7629642 24.0068970 0.2103269 1.0236826 0.3766138 4.3059728 0.91 3.24 0.03 0.14 0.05 0.58 0.3764 0.1220 0.8718 0.7229 0.8291 0.4748 1 1 1 1 1 1 1.45569471 0.01005750 3.15690296 1.16274811 1.78582235 1.10490316 1.45569471 0.01005750 3.15690296 1.16274811 1.78582235 1.10490316 0.14 0.00 0.30 0.11 0.17 0.11 0.7212 0.9762 0.6016 0.7495 0.6930 0.7556 Year 2 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 1inear effects quadratic effects Primary Production May 1-30, Perennial Grass (9/m2) Year 1 control vs others control vs 8 elk/km2 control vs 15 e1 k/km2 control vs 31 elk/km2 1inear effects quadratic effects 1 1 1 1 1 1 0.0410311 1.0721369 5.2584121 14.6285968 17.7366068 22.4860639 0.0410311 1.0721369 5.2584121 14.6285968 17.7366068 22.4860639 0.01 0.19 0.94 2.62 3.18 4.03 0.9345 0.6765 0.3692 0.1566 0.1249 0.0915 1 1 1 1 1 1 2.39128109 1.27640911 0.70339062 3.31009767 2.72990111 0.05901847 2.39128109 1.27640911 0.70339062 3.31009767 2.72990111 0.05901847 0.54 0.29 0.16 0.75 0.62 0.01 0.4887 0.6094 0.7030 0.4189 0.4607 0.9115 Year 2 control vs others control vs 8 elk/km2 control vs 15 elk/km2 control vs 31 elk/km2 1inear effects quadratic effects �252 Cow Wt. Out of Pastures 500 490 480 'S e 470 •.. s: .2l 460 ~ f450 440 430 420 0 10 20 30 40 Elk Density (animals/km2) Year-1 --- 2 Figure 1. Effects of elk grazing during winter on weight~ of adult cows at the end of the spring grazing season. Vertical bars c + Z standard errors of the ~ean. Cow Gain In Pastures 1.90 1.80 1.70 ~1.60 e1.50 .j 1.40 Cl 1.30 >'a 1.20 c CD 1.10 1.00 ~0.90 0.80 0.70 0.60 ff 0 10 20 30 40 Elk Density (animalslkm2) Year-1 --- 2 Figure Z. Effects of elk grazing during winter on average daily gain of adult cows during the spring grazing season. Vertical bars - !Z standard errors of the ~ean. �253 Heifer Wt. Out of Pastures 310 300 290 280 ~270 1:260 .~ 250 :: 240 !230 220 210 200 190 10 0 20 30 40 Elk Density (animals/km2) Year -1 --- 2 Figure 3. Effects of elk grazing during winter on weights of heifers at the end of the spring grazing season. Vertical bars ± Z standard errors of the ~ean. Vertical bars = ± standard errors of the ~ean. Heifer Gain in Pastures 2.30 2.20 2.10 '6'2.00 ~1.90 .:s.1.80 c ~ 1.70 ~ 1.60 'iiI 1.50 C 1.40 CD ~1.3O --------.__ ! 1.20 < 1.10 1 1.00 0.90 0.80 '--T-----r-----,-----.------,-o 10 30 40 Elk Density (animalslkm2) Year -1 Figure 4. Effeci5 of elk grazing gain of heifer5 during the spring f Z standard errors of the ~ean. -- 2 during winter on average grazing season. Vertical daily bars; �254 Calf Birth Wt. 38 sr - 36 01 - C 35 s: 01 .~ 34 :: t '_ 33 32 " ..••....... -~ " 31 30 0 10 20 30 40 Elk Density (anlmals/km2) Year -1 --- 2 Figure 5. Effects of elk grazing during winter on birth welghts of calves. During year 1, there was no opportunity for treatMent to influence calf weights. Vertlcal bars· • Z standard errors of the Mean. Calf Wt Into Pastures 59 57 -g_ 55 s: 01 51 :: 49 .~ t "" <, 53 -, ""- ------ 47 45 1 43 41 0 10 20 30 40 Elk Density (anlmals/km2) Year -1 -2 Figure 6. Effects .of elk grazing du'ring winter on weights of calves at the ~'" ~ '''':';of the spring grazing season. During year 1, there was no opportunity for treatMent to influence calf weights. Vertical bars· + Z standard errors of the Mean. �255 Calf Wt. Out of Pastures 100 90 ---_ ---_ -_ - _ ... 70 6O~r-------~------~------~------~o 10 20 30 40 Elk Density (animals/km2) Year -1 --- 2 Figure 7. Effects of elk grazing during winter on weights of calves at the end of the spring crazing season. Vertical bars Z standard errors of the ~ean. f Calf Gain in Pastures 0.99 0.94 ---- '00.89 ~0.84 .j 0.79 -_-_ -_ ___ (!) ~0.74 ~069 CD' i C) 0.64 <0.59 0.54 0.49 '----T-----.-----.-----,...;------r- o 10 20 30 40 Elk Density (anlmalslkm2) Year -1 --- 2 Figure 8. Effect5 of elk grazing during winter on average daily gain of calves during the spring grazing ~eason. Vertical bars = ~ Z standard errors of the ~ean. �256 ForageClass - Perennial Grasses Age- Standing Uve 12 11 ~10 ••... •.. 9 18 ci S7 ~6 c ~ 5 1 J: r-----+----+-------~-l 2~r_------_r--------,_------_.--------._ o 20 10 30 40 Elk Density (animaJSl1<m2) Year -1 --- 2 Figure 9. Effects of elk grazing during winter on th~ standing crop of live perennial grass at the beginning of the spring grazing season. Vertical bars = Z 5tandard errors of the ~ean. Forage Class - Perennial Grasses Age- Standing Dead 30 ci e o f 10 1 }----- t- ---+-----'--------1 O~r_------_r--------r-------_r--------r_ o 20 10 30 40 Elk Density (animalslkm2) Year -1 --2 FiQure 10. Effects of elk grazing during winter on the standing crop of dead perennial cra5S at the beginning of the 5pring grazing season. Vertical bars = Z standard error5 of the ~ean. �257 Forage Class - Forbs Age - Standing Dead 1.3 12 ~ 1.1 S1.0 iO~ N~~ ~O.6 '§ 0.5 - f-- __ --! <, <, <, •......•.•......••.••....•••.. ~ 0.4 1 0.3 (!J 02 0.1 0.0'--r----r-----r------.-------r-o 10 20 30 40 Elk Density (animal~) Year-1 --- 2 FiQure 1,. Effects of elk grazing during winter on the standing crop of dead forbs at the beginninQ of the spring grazing season. Vertical bars l standard errors of the Mean. E Forage Class - Forbs Age - Standing Live 8 O~r-------_r--------~------_,--------~o 10 20 30 40 8k Density (animalslkm2) Year-1 --- 2 Figure 12. Effect~ of elk grazing during winter on the standing crop of live forbs at the beginning of the spring grazing season. Vertical bars = 2 standard errors of the Mean. �258 Forage CIass- Annual Grasses Age- Standing Uve 3 •... o .,_---- __,_ o ---- 10 -s 30 20 40 Bk Density (animaiS/krn2) Year-1 --- 2 Figure 13. Effects of elk grazing during winter on the stall.'ng crop of live annual grass at the beginning of the spring grazing season. Vertical barz = Z ztandard errors of the Mean. Forage Class - Annual Grasses Age - Standing Dead 1.6 1.5 •••..1.4 t•... 1.3 -1.2 >- 1.1 ~ 1.0 ~0.9 o 0.8 2'0.7 'g 0.6 ~ 0.5 i 0.4 ~ 0.3 e 0.2 •• "- "- "- "- 0.1 0.0 0 10 20 30 40 Elk Density (animalsJkm2) Year-1 --2 Figure 14. Effects of elk grazing during winter on the standing crop of live ennual grass at the beginning of the 5pring grazing 5eason. Vertical bar5 c Z standard errors of the Mean. �259 Forage Class - Perennial Grasses Age - Standing Live 2~r--------r--------~------~--------'-o 10 20 30 40 Elk Density (animalsJkm2) Year -1 --- 2 Figure 15. Effects of elk density on utilization of standing dead grass. Vertical bars c Z standard errors of the ~ean. Forage Class - Perennial Grasses Age-Standing Live 50 40 30 l ~ W ~ e ~ .§ 20 10 0 ~ -10 -20 -30 -40 0 10 20 30 40 Elk Density (animals/km2) Year -1 Figure graS5. -2 16. Effects of elk density on utilization of standing Vertical bars = Z standard error5 of the ~ean. live �260 Forage Class - Perennial Grasses Age - Standing Dead 70 60 50 l .¥ W 40 / / // 30 / / ..t' 20 c:: 0 = 10 ~ 5 0 / r/ I -10 -20 / / / / ---t ' / / / / / / / -30 o 30 20 10 40 Elk Density (anirnaJs/km2) Year -1 --- 2 Figure 17. Effects or elk grazing during winter o~ pri~ary production of perennial grass before May 1. Vertical bars standard errors of the Mean. Forage Class - Annual Grasses = Age - Standing Uve 5 •... o 1I--------1- o ------ 10 J 20 30 40 Elk Density (anirnaJ&'km2) Year -1 -2 Figure 18. Effects of elk grazing during winter on priMary production of annual grass before May 1. Vertical bBrs Z standard errors of the Mean. c 2 �261 Forage Class - Forbs Age - Standing Uve 7 is .....•.. Is i4 I· (2 it 1~---------r--------~-------.---------ro 20 10 30 40 Bk Density (animalslkm2) Year --- 1 --- 2 Figure 19. Ef Fe c t s of e lk grazing production of forbs before May I. errors of the !'lean. Forage Class - Forbs during winter on pri!'lary Vertical bars Z standard 2 Age - Standing Uve 14 13 -. 12 -- ~ 11 Z; 10 ..-I 9 ::::I t! 7 t ~ l~ ~ a. "I: 8 8 5 4 3 2 1 0 -1 0 20 10 30 40 Elk Density (animals/km2) Year -1 --- 2 Figure 20. Effects of elk grazing during winter on pri!'lary production of forbs during May 1-30. Vertical bars = Z standard errors of the ~ean. �262 Forage CW-Perennial GRsses Age-Standing Live }-------t-+-----]- , 8 7~~------_r--------r_------~--------~ o 10 20 30 40 Elk Density (animalSl1an2) Year-1 --- 2 Flgure 21. Effects of elk grazing during winter on pri~ary production of perennial grass during May 1-30. Vertical bars standard error5 of the ~ean. Forage Class-Annual Grasses Age-Standing Uve 18 17 _16 ~ 15 :914 C; 13 I 12 .•.. 11 ~10 C 9 8 :l 7 ,g Ie jI:05 ~ 4 "C 3 a. 2 1 r-------t------t--------------1 O~r- o ~--------~-------'--------~ 10 20 30 40 Elk Density (animaJs/km2) Year-1 --- 2 Figure ZZ. Effects of elk graz'ing during winter on pri~ary production of annual grass during Hay 1-30. Vertical bar5 ~ 2 standard errors of the ~ean. 2 � https://cpw.cvlcollections.org/files/original/e4a71e5f401e12ce56e1447ce0b09d0b.pdf 54fcf7e5120b532221feb3ed7845e73c PDF Text Text 257 Wildlife Research Report July 1988 JOB PROGRESS REPORT State of Colorado Project No. Mammals Research Work Plan Hultispecies Investigations W-153-R-2 ------------------------No. LA ----------------------- Consulting Services for Mark-Recapture Analysis Job No. 5 Period Covered: July 1, 1987 - June 30, 1988 Author: G. C. White Personnel: L. H. Carpenter, R. B. Gill, R. M. Bartmann, G. D. Bear ABSTRACT Progress towards the objectives of this job include: 1. The last six years of survival data from the Piceance mule deer study have been summarized to provide survival estimates from radio-collared animals. 2. A manuscript has been completed on an evaluation of line transect methods for estimating mule deer density. The manuscript is currently under peer review. 3. A manuscript has been completed on an evaluation of capture resighting methods for estimating population size of elk. The manuscript has been submitted for publication to The Journal of Wildlife Management. 4. A variety of consultations were held with CDOW personnel on the application of microcomputer technology to wildlife analysis problems. 5. Simulations of mark-recapture estimates of mountain sheep populations have been developed. 6. An analysis of elk and deer age structure estimates from populations have been developed. 7. An alternative method to compute variances and confidence limits for age-and-sex ratios was investigated. ��259 CONSULTING SERVICES FOR MARK-RECAPTURE ANALYSES Gary C. White P. N. OBJECTIVE Model and simulate population estimates of deer, elk, mountain sheep, and mountain goats with mark-recapture data. SEGMENT OBJECTIVES 1. Evaluate line transect methodology for estimation of mule deer population size. 2. Evaluate capture-resighting methodology for estimation of elk population size. RESULTS MiD DISCUSSION Line transect methodology for estimating mule deer (Odocoileus hemionus hemionus) densities with helicopter surveys was evaluated in pinyon pine (Pinus edulis)-Utah juniper (Juniperus osteosperma) woodland in Piceance Basin, northwestern Colorado. Eight sighting distance models were applied to eight line transect trials flown in enclosures of 194-482 ha where density (21-76 deer/km2) was known. Based on a standardized analysis, the exponential polynomial estimator performed best. It had small bias (-10%, P = 0.261) and deviated least from nominal 95% confidence interval coverage with 6 of 8 (P = 0.057) intervals covering true density. The negative exponential estimator was unbiased (p = 0.821), and the exponential power series estimator was biased (p = 0.033). Both had only 5 of 8 (P = 0.0006) confidence intervals that covered true density. The Fourier serIes estimator underestimated the true population in all 8 cases (P = 0.004), although adding one term beyond the stopping rule proposed by Burnham et ale (1980) lowered, but did not eliminate, this bias (P = 0.024). Confidence interval coverage for the Fourier series (5 of 8, P ~ 0.006) did not change with one additional term. The half-normal estimator-had the greatest bias (-25%, P = 0.006) and only 3 of 8 (P < 0.001) confidence interval covering true density. The hazard function a~d Hermite polynomial estimators had large bias (both -20%, P < 0.02) with 5 of 8 (P = 0.006) and 4 of 8 (P = 0.001) confidence intervals, respectively, covering true density. Deer density estimates from line 2 transect surveys on Piceance Basin winter range, were higher than from a helicopter quadrat census. To obtain the same precision with line transects as with quadrat counts at a density of at least 25 deer/km2, less than half the helicopter time was needed. Density estimates from line transect estimators were biased as much as 25% low, probably because deer on the centerline were not always seen, but this bias is less than for quadrat surveys. A manuscript (included as Appendix A) has been written for submission to The Journal of Wildlife Management. Mark-resighting techniques were evaluated for estimating elk population size. Misc1assifying marked animals as unmarked caused overestimates of population size. Coefficients of variation (4.410.0%) gave precise but biased estimates. Yellow neck collars were found to �260 be more visible during aerial surveys than orange neck collars. Costs for the procedure were high due to the expense of trapping and mUltiple helicopter surveys, but mark-resighting appears to be more reliable than total counts or trend counts in estimating elk populations. A manuscript (included as Appendix B) has been written and submitted for publiction to The Journal of Wildlife Management. An in-depth analysis of age structure data from deer and elk harvests was concluded. The objective of this analysis was to test for differences between seasons (first, second and third) in estimates of age structure from dental cementum data. We hypothesized that data would be biased because of differential vulnerability of young vs. older animals during the first season with that bias getting progressively smaller through the second and third seasons. A memo (included as Appendix C) was prepared and distributed for review and comments. As a result of discussions with Carpenter, Freddy, Bartmann, and Gill, an analysis was undertaken of the Bowden et ale (1984) methodology for estimating variances and computing confidence ratios about sample values of age-and-sex ratios for deer and elk populations. A memo (included as Appendix D) was prepared and distributed for review and comments. Consultations were held with a variety of CDOW personnel on the application of microcomputer technology to specific wildlife analysis problems. Among those consulted were: L. H. Carpenter, R. M. Bartmann, R. B. Gill, G. D. Bear, D. J. Freddy, D. F. Reed, T. D. I. Beck, and N. T. Hobbs. �261 ,. APPENDIX May 20, 1988 Gary C. White Department of Fishery and Wildlife Colorado State University Fort Collins, CO 80523 303-491-6678 RH: Aerial AERIAL Deer Line Transects' LINE TRANSECT IN PINYON-JUNIPER GARY C. WHITE, RICHARD LEN H. CARPENTER, (Burnham et al. 1980, Buckland best. from nominal intervals Laboratory, for estimating Colorado. 317 Center, 317 West Colorado State analysis, (Juniperus St. Paul, MN 55108. osteosperma) Eight sighting (-10%, f = distance in woodland to 8 line transect polynomial 0.261) trials was known. estimator and deviated least with 6 of 8 (f = 0.057) The negative exponential estimator of Fisheries and Wildlife, coverage in models (21-76 deer/km2) the exponential interval Department mule deer (Odocoileus surveys was evaluated 1985) were applied true density. address: Center, 80525 juniper It had small bias covering Research Research of 194-482 ha where density 95% confidence Ipresent Minnesota, CO Ecology with helicopter Basin, northwestern performed State 80526 of Wildlife Resource Piceance Based on a standardized Colorado CO 80526 (Pinus edulis)-Utah flown in enclosures of Wildlife CO methodology densities Biology, 80523 Division Fort Collins, hemionus) and Wildlife Division Natural Line transect pine CO Fort Collins, Fort Collins, University, pinyon Colorado Colorado ROBERT A. GARROTT,l hemionus of Fishery Fort Collins, West Prospect, Abstract: OF MULE DEER DENSITIES WOODLAND M. BARTMANN, Prospect, Biology White et al. ESTIMATION Department University, A was University of �262 White (£ unbiased = (£ = 0.033). covered Both had only 5 of 8 (£ true density. stopping rule proposed eliminate, 0.004), although = 0.024). estimator and Hermite Confidence intervals polynomial estimators respectively, true density. covering surveys on Piceance quadrat census. as with quadrat the helicopter coverage (-25%, £ the true the for the = true density. The hazard (both -20%, £ < 0.001) confidence Deer density estimates Basin winter range were higher To obtain the same precision term. 0.006) and only = had large bias 0.006) and 4 of 8 (£ transects interval covering 0.02) with 5 of 8 (£ helicopter underestimated that adding 1 term beyond had the greatest bias 3 of 8 (f < 0.001) confidence transect intervals (5 of 8, f - 0.006) did not change with 1 additional The half-normal function 0.006) confidence was biased by Burnham et al. (1980) lowered, but did not (£ this bias series = power series estimator The Fourier series estimator in all 8 cases (£ population Fourier 0.821) and the exponential intervals, from 2 line than from a with line counts at a density of at least 25 deer/km2, time was needed. Density estimates <1/2 from line transect estimators were biased as much as 25% low probably because deer on the centerline were not always seen, but this bias is less than for quadrat surveys. ~ Key Words: Aerial census, estimator, exponential estimator, negative function hemionus. estimator, Colorado, line transect, power series estimator, exponential Hermite WILDL. MANAGE. estimator, polynomial Fourier exponential half-normal estimator, OO{O):OOO-OOO series polynomial estimator, Odocoileus hazard hemionus �263 APPENDIX B August 12, 1987 George Bear Colorado Division of Wildlife P.O. Box 39 Maybell, CO 81640 (303)272-3247 RH: Bear et al. -- Observability bias OBSERVABILITY BIAS IN MARK-RESIGHTING ESTIMATES OF ELK POPULATIONS George D. Bear, Colorado Division of Wildlife, 317 W. Prospect Street, Fort Collins, CO 80526 Gary C. White, Department of Fishery and Wildlife Biology, Colorado State University, Fort Collins, CO 80523 Len H. Carpenter, Colorado Division of Wildlife, 317 W. Prospect Street, Fort Collins, CO 80526 R. Bruce Gill, Colorado Division of Wildlife, 317 W. Prospect Street, Fort C9llins, CO 80526 David Essex, Rocky Mountain National Park, Estes Park, CO 80517 J. WILDL. MANAGE. 00(0):000-000 Abstract: Mark-resighting techniques were evaluated for estimating elk population size. Misclassifying marked animals as unmarked caused over estimates of population size. Coefficients of variation (4.4-10.0%) gave precise but biased estimates. Yellow neck collars were found to be more visible during aerial surveys than orange neck collars. Costs for the procedure were high due to the expense of trapping and multiple helicopter surveys, but mark-resighting appears to be more reliable than total counts or trend counts in estimating elk populations. Key words: Biotelemetry, mark-resighting, capture-recapture, captureresighting, Cervus elaphus, elk, hypergeometric, mark-recapture, population estimation. ��265 APPENDIX C M E M 0 RAN DUM June 19, 1988 To: Distribution From: Gary C. White Q._cJ. Re: Analysis of Elk and Deer Age Structure from Tooth Collections Introduction An ongoing debate has existed concerning the validity of age structure estimates made from harvested animals. The population age structure is estimated from ages determined by sectioning incisors collected from animals harvested by sport hunters. Several potential problems exist. First, ages determined from tooth sectioning may have questionable accuracy. Second, the sample of animals collected by sport hunters may not reflect the population age structure because of either (or both) selection by hunters or by differences in vulnerability of animals by age. This memo addresses the second question. For any reasonable population, the true age structure is not known. Thus, no means for testing the sample against the truth is available. However, if a representative (random) sample of the population is taken by sport hunters, there should not be differences between 2 consecutive samples from the same population. That is, the 2 age structure estimates from 2 different samples should be the same. The season structure of deer and elk seasons in Colorado allows for testing this hypothesis because males are harvested in 3 separate seasons, whereas females are harvested in 2 separate seasons. In addition, some later seasons are occasionally allowed, providing more data for testing the hypothesis. Methods A total of 500 deer and 793 elk teeth were sectioned and aged for 1986, and 163 deer and 949 elk for 1987. The breakdown of the sample by DAU, GMU, year, sex, and season are provided in pages 1-34 of the accompanying SAS listing. Because few older age animals occur in the sample, pooling of age classes was necessary for chi-square tests. The distribution of ages across all areas are shown on pages 35-38. For deer, pooling of ages 5 and greater was used. For elk, ages 5-8 were pooled, and 9 and greater. The sample was not collected uniformly across seasons within areas, so that most comparisons of seasons were not cleanly delineated to specific areas. Further, most potential comparisons lacked adequate sample size to provide reasonable statistical power. Thirty tests were performed across �266 Elk and Deer Age Structure from Tooth Collections -- June 19, 1988 Page 2 samples taken on a OAU basis, but most were based on too small of a sample. Further, some of the samples were from different GMU's within the same OAU between seasons, i.e., the samples from 2 seasons may not have been from the same population. Thus, interpretation of the results must be made with care. To determine if the samples for the seasons came from the same areas, refer to the output on pages 1-21, where the harvest by GMU is presented. Several statistics are output from SAS to determine if the null hypothesis of equal age distributions is rejected. The familiar Pearson chi-square is provided, plus the slightly more powerful likelihood ratio chi-square. I have used the likelihood ratio statistic for testing the null hypothesis. Neither of these statistics are valid for small samples, so the Fisher exact test has also been computed for small samples. This statistic is not totally valid for this situation because the marginals of the tables are random variables. However, for the many tables with small samples, this statistic is useful to help interpret the likelihood ratio test. Results Several of the tests for males were significant (£ < 0.05). Generally, this result is not particularly interesting because many more yearling males were harvested in the third season, when antler point restrictions were removed for some OAU's. The best example of this phenomena is for the 1986 E-43 data (page 78). Another test that rejected the null hypothesis is for 1986 0-7 (page 50). However, the distribution of the harvest across GMU's was not uniform within the OAU for each season, so this test probably represents differences due to sampling effort. The best test of the null hypothesis was provided by the data from DAU E-6, White River. Over 400 females were aged in 1987. In 1986, both males and females rejected the null hypothesis (pages 82-84), suggesting strong differences between the 2 seasons for females and 3 seasons for males. In 1987, a late hunt was conducted in E-6 (GMU 33), labeled as season 4 in the output. When the late hunt is included in the analysis, the null hypothesis is rejected for females (pages 85-86), but not males (page 87). However, if the late hunt is not included, the null hypothesis is no longer rejected (£ = 0.250) for females (pages 40-41). The rejection for females may be because of differences in age structure of GMU 33 from the rest of the unit, and not necessarily that the late season produced a different age structure. Data were pooled for the entire state to test the null hypothesis, with several of these tests significant (pages 88-105). However, because of differences in sampling areas and intensities between seasons, I doubt that these tests contribute much information concerning the question being addressed here. Conclusions �267 Elk and Deer Age Structure from Tooth Collections -- June 19, 1988 Page 3 The 1986 E-6 data suggest strongly that differences in age structure estimates between seasons occur. Not rejecting the null hypothesis does not contribute evidence that it is true, particularly for the small sample sizes (and hence low power) in the data available. Thus, the many tests that were not significant contribute little information relative to the bias. Rejection of the null hypothesis for data where areas and seasons are not confounded does contribute evidence that a biased sample of age structure is obtained from hunter harvest. Such is the case for 1986 E-6. Not rejecting the null hypothesis in 1987 for E-6, where the largest sample sizes occur, suggests that not every year has major differences between seasons. Suggestions for Future Work The tooth collection should be limited to a few GMU's, so that adequate sample sizes are obtained within a small area for all seasons. Much of the tooth sectioning effort is wasted when teeth from across the state are aged, but adequate samples are not available from multiple seasons in a single GMU. Confounding of seasons and areas severely limits the interpretation of the test results. The coming year presents some excellent opportunities for testing the hypothesis with deer, because the number of female permits is greatly increased. I suggest that several key GMU's be selected, and teeth solicited from only these units. In particular, I would suggest that GMU's 22 (0-7), 10 (0-6), and 33 (0-42) be selected to complement existing and planned research. Elk teeth should continue to be collected from E-6, particularly if several GMU's could be emphasized instead of pooling data from the entire OAU to achieve large sample sizes. I will incorporate dBase programs into the database I am currently developing to include the tooth age data in the data base. Then, standardized recording and reporting procedures will be available. Instead of recording the season as 1-4, the season codes used by Harlan Riffel should be incorporated in the tooth database. I will attempt to do this with the existing data, but probably will not be able to separate limited hunt males from over-the-counter hunt males. A final observation is worth presenting. Collection of teeth is only feasible when the management biologists are interested in the project, and understand the significance. I believe a journal paper could be developed from such data, particularly if they were collected to minimize all the problems discovered in the current data. This is the type of project that could be used to motivate several of the area/district biologists, and further improve the cooperation between the research section and management biologists. Oistribution: Len Carpenter ~ce Gill Jim Lipscomb �268 Comparison of Age Distribution Across Seasons Number of Animals by GMU Analysis DAU D-1 Variable GMU 2 : AGE YEAR SEX SEASON 1986 F M D-10 20 30 42 521 D-13 43 D-11 D-12 1986 1986 1987 1987 1986 F M M M F F M D-15 48 56 1987 M 1986 F M 1987 F M D-16 49 1986 F 57 1987 F 1986 F M 58 1987 F 2 M 1 2 3 3 3 3 3 1 3 3 3 1 2 1986 F M 1986 F M 1987 F M 46 1987 M D-19 51 62 1987 M 1986 M D-2 3 1986 1987 1986 1986 4 D-20 53 2 M M D-17 2 2 2 3 2 3 2 2 2 2 2 2 1 2 3 2 3 1 2 3 3 3 2 2 3 1987 F 581 11:05 SUnday, June 19, 1988 M M M M 2 1 3 2 3 3 3 N Obs 1 1 2 1 2 6 1 1 1 1 1 6 5 2 1 9 1 2 10 1 1 1 2 1 2 1 2 1 2 2 10 4 14 4 2 25 4 2 2 5 1 1 3 6 1 1 4 Minimum 0 3 1 1 2 2 5 5 4 4 5 1 2 2 4 3 2 4 2 Maximum 0 3 1 1 2 3 5 5 4 4 5 6 5 3 4 10 2 5 8 2 2 4 4 2 2 2 3 3 2 2 8 2 3 1 1 1 1 2 1 2 2 1 2 2 4 2 1 3 4 1 3 3 8 2 3 8 3 6 4 2 8 8 3 6 7 13 2 5 2 4 3 2 3 4 4 �269 Comparison of Age Distribution Across Seasons Ntnnber of Animals by GMU Analysis D.AU Variable: GMU AGE YEAR SEX SEASON Ir21 54 Ir22 55 1986 M 1987 M 1986 M Ir24 551 70 1986 M 1986 F 71 1986 F 66 1987 M 1986 M 67 1986 M M M Ir25 Ir26 68 Ir27 Ir29 Ir3 681 38 73 16 161 1987 1986 1987 1987 1987 1987 1986 1987 1986 M M M M M M M M M 17 1986 F 171 1986 M 83 1986 F M Ir31 11:05 SUnday, June 19, 1988 M 1987 M D-32 112 85 1986 M 1986 M 851 D-33 143 D-34 84 1987 1986 1987 1986 F M M F M 1 2 1 2 3 2 2 3 3 3 3 2 1 2 1 2 3 2 3 2 2 2 2 1 3 1 2 3 3 3 1 2 3 3 1 2 3 2 3 3 2 3 3 N Obs Min:ilnum Maximum 1 1 3 2 2 1 2 1 2 3 1 3 1 2 1 3 5 5 2 1 1 3 3 5 2 2 2 2 3 2 2 2 3 0 2 1 1 3 0 5 1 1 2 1 2 3 2 2 8 3 1 2 3 5 3 3 4 2 4 5 5 2 4 7 3 3 5 2 2 2 2 3 4 2 5 3 10 6 9 10 3 0 5 7 1 9 2 2 2 1 2 2 3 1 7 2 1 2 2 22 1 2 6 2 3 1 1 1 5 4 2 1 1 1 2 1 1 1 3 3 3 1 61 21 35 34 1 1 1 2 1 3 1 2 1 2 5 5 5 3 2 2 3 2 2 �270 Corrparison of Age Distribution Across Seasons Number of Animals by GMU Analysis I:llill D-34 Variable GMU 86 : AGE 1987 F M F M D-35 80 81 1986 F M 1987 M 1986 M 1987 F M D-36 76 79 1986 1986 M M D-37 D-39 82 63 1987 1987 1986 D-4 19 1986 M M F M F M 1987 191 1986 8 1987 1987 9 D-40 D-42 D-43 64 33 25 D-43 26 34 34 11:05 SUnday, June 19, 1988 YEAR SEX SEASONN Obs 1986 1986 1987 1987 1987 1987 1986 1986 1986 1987 F M F M M M M M M F F M M F M F M 5 2 2 2 3 1 2 3 2 2 3 2 3 2 3 2 1 3 2 2 3 2 1 2 2 2 3 1 2 3 3 3 3 3 1 1 2 1 3 2 2 2 2 2 2 2 2 2 5 2 3 3 1 3 4 1 9 7 5 2 5 5 2 1 3 2 1 12 4 1 3 11 2 1 2 3 2 2 1 1 43 2 3 2 2 1 1 1 1 1 1 1 1 1 2 Minimum Maximum 0 4 2 0 4 2 1 1 1 1 2 1 1 1 2 4 1 1 1 1 2 9 1 1 0 3 1 1 2 2 2 0 1 3 2 2 2 2 2 4 3 3 2 3 4 11 2 4 4 6 1 4 6 4 2 3 8 6 4 2 3 1 8 6 9 5 5 0 3 1 2 4 2 2 0 8 4 3 4 3 2 2 4 3 3 2 2 2 2 2 2 2 4 2 �271 Corrparison of Age Distribution Across Seasons Nlnnber of Animals by GMU Analysis I:l.AU 0-44 0-46 0-49 Variable GMU 881 114 105 : AGE M M F M 0-5 0-7 0-8 1986 F 22 23 1986 1986 1987 1986 1986 M M M M M M 24 15 1987 1986 1986 87 11 12 M M F M 0-8 35 35 36 1987 1986 1987 1986 F M F F M 1987 0-9 18 181 1987 1986 F M M F M 27 1986 F M 28 1987 37 1986 1987 F M M F M 371 1986 F M E- E-1 109 114 143 89 1 11:05 SUnday, June 19, 1988 YEAR SEX SEASON NObs 1986 1986 1987 1987 1986 1986 1987 1987 1986 1987 F M F M M F M F M 7 3 2 2 2 2 2 2 3 3 3 1 2 3 2 1 2 1 2 3 2 2 2 2 2 2 3 2 2 2 2 2 3 3 2 2 2 2 2 3 2 2 2 3 3 2 2 2 1 1 2 2 1 1 2 1 1 1 15 2 3 1 5 1 1 3 1 1 2 1 2 3 3 1 2 1 2 2 2 1 1 1 1 1 1 1 1 2 1 4 2 2 1 1 1 Minllnum 4 4 2 2 2 1 1 1 2 2 1 2 1 2 2 0 1 3 3 1 3 0 2 3 2 2 0 2 2 2 4 6 5 5 3 5 6 2 4 1 1 2 3 3 1 1 5 Max:irnum 4 4 3 6 2 1 1 1 2 2 3 3 2 2 3 0 1 3 3 1 7 0 2 7 3 2 1 2 2 4 6 6 5 5 3 5 6 2 4 1 1 4 3 5 1 1 5 �272 Corcparison of Age Distribution Across Ntnnber of Animals by GMU Analysis Variable: 11: 05 SUnday, June 19, 1988 AGE GMU YEAR SEX SEASON NObs 201 1987 E-I0 22 1987 E-12 30 31 32 36 1986 1987 1987 1986 1987 E-13 28 1986 1987 D.AU F M F M M F F F F M F F M E-13 E-14 E-15 E-16 E-17 37 1987 371 371 42 1986 1987 1987 421 1987 521 43 471 44 444 45 1987 1987 1987 1987 1986 1986 1987 481 1986 56 1986 F M M F F M F M F F F M M F F M F M F M E-18 E-18 50 50 500 1987 1986 1986 M F M 1987 F M M 1986 Seasons 2 2 2 3 3 3 3 2 2 2 2 2 2 3 2 3 3 3 2 3 2 2 2 1 3 3 3 3 2 1 2 2 3 2 2 2 2 3 1 3 2 3 1 3 2 2 3 1 1 1 1 1 1 1 1 1 1 2 4 1 4 1 6 1 3 1 1 1 1 2 1 1 1 1 1 1 1 1 11 1 3 1 1 1 2 3 5 1 2 2 3 1 1 1 Minllnum 2 2 1 16 0 5 3 6 5 3 3 2 1 0 1 0 0 0 1 2 9 1 3 2 1 3 4 0 1 3 0 1 4 0 4 1 3 4 1 1 2 1 1 1 2 4 1 Maximum 2 2 1 16 0 5 3 6 5 3 3 5 1 1 1 3 0 0 1 2 9 1 3 2 1 3 4 0 1 3 0 11 4 3 4 1 3 18 5 4 2 1 1 2 2 4 1 �273 Comparison Analysis ]),AU E-2 Variable GMU of Age Distribution Across Number of Animals by GMU : AGE SEX SEASON N Cbs 1987 F M F F F M 1986 1986 1986 441 5 1987 1986 61 1986 F F M F 62 1987 1986 M M E-22 49 1987 1986 M F E-22 49 1986 1987 M F E-20 M M 57 1986 F 1987 M F M 58 11: 05 SUnday YEAR 14 3 4 1986 F M 1987 F M E-23 E-23 581 581 1986 1986 E-24 70 1987 1986 F F M F F 1987 F Seasons 2 2 2 2 3 2 3 3 3 3 2 2 2 2 3 2 2 3 2 2 3 1 2 3 2 3 2 2 3 2 3 2 3 2 3 2 3 1 2 3 2 3 3 2 2 3 2 3 1 2 2 4 1 1 1 1 1 1 1 2 4 1 1 11 6 1 19 2 6 8 1 11 12 2 26 2 3 1 13 5 7 7 11 5 2 6 4 2 1 5 1 28 15 2 I Mininn.nn 2 2 0 5 1 2 2 1 3 6 2 3 2 2 2 4 0 0 5 0 1 1 1 3 0 1 1 0 3 0 1 0 0 1 1 0 3 2 0 1 0 8 1 1 0 0 6 June 19 I 1988 MaxiIm.nn 4 2 1 8 10 2 2 1 3 6 2 3 3 3 2 4 16 13 5 11 6 9 11 3 9 11 3 10 7 3 1 10 11 3 4 10 8 3 2 2 1 8 4 1 10 13 8 �274 Comparison of Age Distribution Across Seasons Number of .Anilnal.s by GMU Analysis Di\U E-25 Variable: YEAR SEX SEASON N Obs 71 1986 F 66 1987 1986 F F M F 67 1986 1987 68 1986 1987 M F M F F M F M M F M 681 681 1986 1987 E-27 86 1986 E-28 E-3 69 16 1987 1986 1986 F M M F F 161 1986 M F 17 1986 M F E-26 M 171 1987 1986 F F M 6 1986 F E-31 78 1986 E-32 80 1986 F M F M E-3 11: 05 SUnday, June 19, 1988 GMU 1987 E-26 AGE 2 3 2 2 2 2 3 2 3 3 2 3 2 2 2 2 3 2 2 3 3 1 3 3 2 3 3 2 3 3 2 3 1 2 3 3 2 3 2 3 2 3 2 2 3 2 3 13 24 1 3 2 12 5 2 4 2 14 6 3 1 5 1 1 2 1 1 1 1 1 3 11 7 1 7 7 3 3 3 1 1 4 1 9 7 1 3 1 6 4 5 5 3 1 Mi.niJnum Maximum 0 0 16 2 2 1 3 2 2 1 0 0 0 1 1 5 2 1 4 1 0 3 4 3 0 0 2 0 0 1 3 1 4 2 1 5 0 0 2 2 1 0 2 2 0 2 1 16 12 16 6 4 17 10 2 6 2 6 7 3 1 5 5 2 12 4 1 0 3 4 17 9 5 2 9 6 2 7 4 4 2 1 5 4 5 2 4 1 3 10 3 7 3 1 �275 Comparison of Age Distribution Across Seasons Number of Animals by GMU Analysis IWJ Variable GMU 11:05 SUnday, Jrme 19, 1988 : AGE YEAR SEX SEASON N Obs Minimum Maxi.mLnn --------1987 81 1986 F M F M 1987 F M E-33 83 1986 F M E-33 83 85 1987 1987 1986 851 1986 M M F M F M E-34 76 1986 F M 1987 79 1986 1987 F M F M F M F F M E-38 29 38 1987 1987 E-39 39 1986 F 1987 F M 46 1987 F 2 2 2 3 1 2 3 2 1 2 3 3 1 2 3 1 3 2 2 2 3 1 2 3 2 3 2 3 2 3 3 3 3 2 2 3 2 1 2 2 3 2 3 1 2 3 2 4 9 2 5 6 4 8 13 3 4 1 35 30 27 4 1 1 2 2 3 6 9 12 7 6 7 9 3 1 2 1 8 12 8 3 1 3 1 1 4 8 14 1 2 6 3 13 2 0 1 1 2 1 1 0 2 1 2 0 2 2 2 3 0 6 3 3 2 3 3 1 2 1 1 1 6 0 1 0 1 0 2 6 3 3 2 0 0 0 5 3 0 2 0 5 4 2 9 3 2 3 15 3 2 2 15 7 7 4 3 0 7 3 12 10 8 7 7 14 17 6 3 6 3 1 18 2 9 4 6 6 3 2 9 9 14 5 5 3 12 6 �276 Corrparison Analysis Dt\U E-4 Variable GMU 19 YEAR 1986 1987 of Age Distribution Across Number of Anilnals by GMU : AGE M F M F M 8 1986 1987 M F E-41 9 54 1987 1986 E-41 54 1986 1987 F F M M F E-42 E-43 53 55 1986 1986 M M F M 1987 F M 551 1986 F M 1987 F M E-6 12 1986 F E-6 12 1986 1987 M F M 13 11:05 SUnday, June 19, 1988 SEX SEASON N Obs 1986 F 1987 M F 3 2 2 2 2 3 1 3 2 2 3 2 2 1 3 2 3 2 3 2 3 1 2 3 2 3 2 3 2 1 3 2 3 2 3 2 3 2 2 3 1 3 2 3 3 2 3 Seasons 5 5 6 1 11 5 1 2 1 13 6 1 1 1 5 15 18 1 1 2 17 4 7 13 16 10 4 1 1 5 2 20 4 1 5 12 10 1 62 18 1 1 11 23 1 40 20 Mi.ni1num Maximum --------- 2 2 0 3 0 2 2 0 2 0 0 5 3 3 1 0 0 0 4 0 0 2 2 1 0 0 0 1 1 1 1 0 1 0 0 0 1 1 0 0 0 0 0 0 2 0 0 8 5 7 3 11 5 2 1 2 13 7 5 3 3 2 14 7 0 4 5 10 5 4 3 14 10 3 1 1 5 1 16 5 0 1 5 13 1 20 17 0 0 7 13 2 16 15 �277 Comparison of Age Distribution Across seasons Number of Animals by GMU Analysis Di\U Variable: GMU YEAR SEX SEASONN Obs M 131 E-6 1986 F 1987 M F M F M 23 1986 23 1987 1987 F F M 24 1986 F M 1987 F 1986 M F 1987 F 25 M 26 1986 1987 E-6 33 1986 33 1987 F M F M F M F M 34 E-7 15 1986 11:05 SUnday, June 19, 1988 AGE 1987 F M F 1986 M M 2 3 2 3 2 2 3 2 2 1 2 3 2 3 2 3 2 1 2 3 2 3 3 2 3 2 3 2 3 2 2 2 3 3 2 3 2 3 4 2 4 2 2 2 3 2 1 1 1 9 13 2 41 10 2 3 7 8 3 63 28 1 2 1 18 8 1 34 5 1 2 5 16 11 1 2 4 2 1 4 1 3 7 33 9 54 2 1 4 1 13 1 3 1 Minimum 1 0 0 0 1 0 1 0 0 2 2 2 0 0 0 0 1 2 1 2 0 1 2 0 1 0 1 0 0 0 2 0 0 0 0 1 0 1 0 0 0 0 3 2 2 0 4 MaxiJ.nurn 1 0 9 9 2 14 8 0 1 2 2 3 14 16 0 0 1 3 2 2 16 9 2 3 3 19 15 0 2 6 4 0 3 0 6 12 10 17 17 0 0 5 3 7 2 3 4 �278 Conparison Analysis Illill E-8 E-9 0-1 Variable GMU YEAR 27 18 1987 1986 1987 181 1986 20 1986 1986 0-10 1986 0-11 0-12 1986 1987 0-13 1986 0-15 1986 1987 of Age Distribution Across Seasons Number of AniInals by GMU : AGE SEX M M F M F M F F M F M M F M F M F M F M 0-16 1986 M 0-16 1986 1987 M F M 0-17 1987 M 0-19 1986 M 0-2 1986 M 1987 1986 1986 1987 1986 M M M M M 0-20 0-21 0-22 11: 05 SUnday, June 19, 1988 SEASON 3 1 3 3 2 2 3 2 2 2 3 2 3 2 2 2 2 2 1 2 3 2 3 1 2 3 2 3 1 2 3 2 3 1 2 3 1 2 1 3 2 3 3 3 1 2 1 N Obs Minimum 1 1 1 2 6 1 2 1 1 2 1 2 6 1 1 1 1 6 5 2 1 9 1 2 11 1 1 7 2 2 37 4 8 1 2 16 2 6 1 3 6 1 1 4 1 2 2 1 1 2 1 0 4 3 0 3 1 1 2 2 5 5 4 4 1 2 2 4 3 2 4 2 2 3 1 2 3 1 2 1 8 2 1 1 2 4 2 1 4 3 1 1 1 3 Maximum ------1 1 2 6 7 4 3 0 3 1 1 2 3 5 5 4 4 6 5 3 4 10 2 5 8 2 3 8 3 8 6 3 7 8 3 13 2 5 4 3 2 4 3 4 1 2 3 �279 Comparison of Age Distribution Across Seasons Number of Animals by GMU Analysis DMJ Variable GMU YEAR SEX SEASON N Cbs 0-24 1986 F 0-25 1987 1986 M M M 0-27 0-29 0-3 1987 1986 1987 1987 1987 1986 M M M M M F M 1987 1986 M 0-31 0-26 F M 1987 M 0-32 1986 M 0-33 0-34 1987 1987 1986 F M F M 1987 F M 0-35 1986 F M 1987 F M 0-36 11:05 SUnday, June : AGE 1986 M 1987 M 2 3 2 3 3 2 1 2 3 2 3 2 2 2 3 1 2 3 3 3 1 2 3 2 3 2 3 3 2 2 2 3 2 3 1 2 3 2 2 3 2 1 2 3 2 3 2 10 1 2 3 24 1 4 9 1 1 1 9 2 1 1 6 4 5 1 61 21 35 34 1 1 3 2 3 2 6 2 2 3 3 1 3 4 1 14 12 2 1 5 5 3 12 4 Minimum 1 2 2 1 1 3 1 2 5 5 2 1 3 3 3 2 2 2 2 0 2 1 1 3 0 1 1 2 2 0 4 2 2 0 4 2 1 1 1 1 2 4 2 1 1 1 2 19, 1988 Maximum 8 2 3 3 5 3 3 4 5 5 2 7 3 3 3 5 5 4 2 10 6 9 10 3 0 7 5 9 5 5 4 3 11 2 4 4 6 1 4 8 6 4 4 2 3 8 6 �280 Comparison of Age Distribution Across Seasons Number of Animals by GMU Analysis [l?ill Variable GMU : AGE YEAR SEX SEASON N Obs D-37 D-39 1987 1986 D-4 1986 M F M F D-4 1986 M 1987 F M 1987 1987 1986 M F F M F M M M F M F M M D-40 D-42 D-43 1987 D-44 D-46 D-49 1986 1986 1987 D-5 1986 D-7 1986 D-7 D-8 1987 1987 1986 M M F M 1987 F D-9 11:05 SUrrlay, June 19, 1988 1986 1987 M F M F M 1 2 2 2 3 1 2 3 3 1 2 3 2 2 2 2 2 2 3 2 2 2 2 2 1 2 3 2 3 2 1 2 2 3 2 2 2 2 3 2 3 E- 1986 1987 E-l 1986 F M M F M 2 2 2 3 3 2 1 3 11 2 2 4 3 45 2 5 2 2 1 1 1 2 2 3 1 1 2 2 1 1 20 4 5 1 1 2 1 6 5 1 3 5 5 3 2 1 2 1 2 4 2 2 1 Mi.niJm.nn 9 1 1 0 0 1 1 1 2 2 2 2 2 4 2 2 2 2 4 4 2 2 2 1 1 1 1 2 2 0 1 1 3 3 2 0 2 3 4 5 2 1 1 2 3 3 1 Maximum 9 5 5 0 3 3 2 8 2 4 4 2 2 4 2 2 3 4 4 4 3 6 2 1 3 3 2 2 2 0 1 3 7 3 3 6 5 6 6 5 5 1 1 4 3 5 1 �281 Comparison of Age Distribution Across Number of Anilnals by GMU Analysis Di\U E-10 E-10 Variable GMU YEAR SEX SEASON NObs F M 1986 1987 1987 M F F M E-12 1986 1987 E-13 1986 F F M F M 1987 F M E-14 1987 F M E-15 E-16 1987 1986 F F M 1987 F M E-17 E-17 1986 1986 F F M E-18 1987 1986 M F M 1987 F M E-2 1986 F M E-20 1987 1986 F F M E-22 11:05 SUnday, June : AGE 1987 1987 1986 M F 2 2 3 2 3 3 2 2 2 2 2 2 3 2 3 2 3 1 2 3 3 2 1 2 3 2 2 3 1 2 3 2 3 1 3 2 2 2 3 2 3 3 2 2 3 2 2 Seasons 2 2 1 2 2 1 1 1 2 4 1 1 6 1 9 3 1 1 1 1 2 1 1 11 1 4 2 2 3 1 5 1 2 2 4 4 2 4 5 1 2 1 1 5 1 3 35 Minimum 1 2 5 1 3 0 5 3 3 2 1 1 0 1 0 3 3 2 1 1 0 0 3 1 4 0 3 4 1 1 1 2 1 1 1 2 2 0 1 2 2 1 2 2 2 2 0 19, 1988 Maxinrum 2 5 5 6 16 0 5 3 3 5 1 1 2 1 3 9 3 2 1 1 4 0 3 11 4 3 4 18 5 1 4 2 1 1 2 4 4 8 10 2 6 1 2 3 2 4 16 �282 Con'prrison of Age Distribution Across Seasons Nmnber of Anilnals by GMU Analysis IlMJ Variable GMU : AGE YEAR SEX SEASONN Cbs M E-22 11:05 SUnday, Jl.ll1e 19, 1988 1987 F M E-23 1986 F E-24 1987 1986 M F F E-25 1987 1986 F F M 1987 F E-26 1986 M F M E-26 1987 1987 F M E-27 1986 E-28 E-3 1987 1986 1986 F M M F F M E-31 1987 1986 E-32 1986 F F M F M 1987 F M 3 2 3 2 3 1 2 3 2 3 3 2 2 3 2 2 3 2 3 2 3 2 2 2 3 2 2 3 3 1 3 3 2 3 1 2 3 3 2 2 2 3 1 2 3 2 1 23 10 7 56 9 8 17 6 2 1 5 1 41 39 3 3 4 2 2 26 11 2 3 1 1 7 2 1 1 1 1 3 31 30 1 2 11 1 4 5 2 10 6 7 9 17 3 Minimum 0 1 1 0 1 1 0 1 0 8 1 1 0 0 6 2 2 2 1 0 0 2 0 1 2 1 4 1 0 3 4 3 0 0 4 2 1 5 2 2 1 0 2 1 1 0 2 Maximt.nn 13 5 4 11 8 9 11 3 1 8 4 1 16 13 16 6 6 4 2 17 10 2 3 1 2 12 5 1 0 3 4 17 9 6 4 2 4 5 10 3 2 9 3 3 3 15 3 �283 Comparison of Age Distribution Across Nlnnber of AniInals by GMU Analysis J:li\U E-33 Variable GMU : AGE F M E-34 1987 M 1986 F M 1987 F M E-38 1987 F M E-39 1986 F 1987 F E-39 1987 M E-4 1986 F M F 1987 M E-41 E-42 E-43 11:05 SUnday, June YEAR SEX SEASON N Cbs 1986 1986 F M 1987 F 1986 1986 M M F M Seasons 2 3 2 3 1 2 3 1 3 2 3 2 3 2 3 2 3 2 3 1 2 2 3 2 3 1 2 3 2 2 2 3 1 3 2 1 2 3 2 3 2 3 2 3 1 2 3 Minimum 13 1 5 41 39 41 11 1 1 6 15 9 15 9 2 3 1 3 1 1 1 4 8 27 6 2 11 3 6 2 25 11 1 2 1 1 5 5 15 18 1 1 3 17 9 7 15 0 2 3 0 2 2 1 3 0 2 0 1 1 0 0 2 1 3 6 3 2 0 0 0 2 3 0 2 0 2 0 0 2 0 3 3 1 1 0 0 0 4 0 0 1 2 1 19, 1988 Maximum 4 2 12 15 8 7 7 3 0 14 18 6 3 9 3 4 1 6 6 3 2 9 9 14 8 5 5 12 7 3 13 7 2 1 3 3 3 2 14 7 0 4 5 10 5 4 3 �284 Corrparison Analysis I::lt\U E-43 Variable GMU of Age Distribution Across Number of .Animals by GMU : AGE F F M E-6 1986 F M 1987 F M E-7 E-8 1986 1987 1986 M M F M 1987 F M E-9 11:05 SUnday, June YEAR SEX SEASON N Obs 1987 1987 1986 F Seasons 2 3 2 3 2 3 1 2 3 2 3 4 1 2 3 4 1 3 2 2 3 3 3 36 14 5 6 49 51 25 22 12 303 106 54 1 10 8 1 2 1 6 1 1 2 2 Minimum 0 0 0 0 0 0 2 1 1 0 0 0 0 0 0 0 1 1 0 4 2 1 3 19, 1988 Maxilnurn 16 10 3 1 9 13 3 4 12 20 17 17 0 3 2 0 4 1 7 4 2 6 3 �285 Comparison of Age Distribution Across Seasons Distribution of AniInals by Age 11:05 SUnday, June 19, 1988 SPECIFS=Deer YFAR=1987 AGE 0 1 2 3 4 5 6 7 8 9 10 ------- Frequency Percent 21 89 149 90 60 47 26 5 9 2 2 4.2 17.8 29.8 18.0 12.0 9.4 5.2 1.0 1.8 0.4 0.4 CUmulative Frequency 21 110 259 349 409 456 482 487 496 498 500 CUmulative Percent 4.2 22.0 51.8 69.8 81.8 91.2 96.4 97.4 99.2 99.6 100.0 SPECIFS=Deer YFAR=1987 AGE 0 1 2 3 4 5 6 7 8 9 10 11 13 Frequency Percent 2 11 54 41 19 14 9 4 4 2 1 1 1 1.2 6.7 33.1 25.2 11.7 8.6 5.5 2.5 2.5 1.2 0.6 0.6 0.6 CUmulative Frequency 2 13 67 108 127 141 150 154 158 160 161 162 163 CUmulative Percent 1.2 8.0 41.1 66.3 77.9 86.5 92.0 94.5 96.9 98.2 98.8 99.4 100.0 �286 comparison of Age Distribution Across Seasons Distribution of Animals by Age 11:05 SUnday, June 19, 1988 -----AGE 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 -----AGE 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 SPECIFS=Elk YFAR=1986 CUmulative Frequency Percent Frequency 67 121 197 138 82 58 34 27 16 16 9 5 5 8 2 2 2 2 2 8.4 15.3 24.8 17.4 10.3 7.3 4.3 3.4 2.0 2.0 1.1 0.6 0.6 1.0 0.3 0.3 0.3 0.3 0.3 67 188 385 523 605 663 697 724 740 756 765 770 775 783 785 787 789 791 793 SPECIFS=Elk YFAR=1987 CUmulative Frequency Frequency Percent 121 139 193 148 88 62 56 35 27 21 13 9 6 5 7 4 8 4 1 1 1 12.8 14.6 20.3 15.6 9.3 6.5 5.9 3.7 2.8 2.2 1.4 0.9 0.6 0.5 0.7 0.4 0.8 0.4 0.1 0.1 0.1 121 260 453 601 689 751 807 842 869 890 903 912 918 923 930 934 942 946 947 948 949 CUmulative Percent 8.4 23.7 48.5 66.0 76.3 83.6 87.9 91.3 93.3 95.3 96.5 97.1 97.7 98.7 99.0 99.2 99.5 99.7 100.0 CUmulative Percent 12.8 27.4 47.7 63.3 72.6 79.1 85.0 88.7 91.6 93.8 95.2 96.1 96.7 97.3 98.0 98.4 99.3 99.7 99.8 99.9 100.0 �287 Corrparison of Age Distribution Across Seasons comparison Across 3 Seasons for Elk in D.MJ E-6, 1987, Males 11:05 SUnday, June 19, 1988 TABlEOF SEASON BYAGE SEASON AGE Frequency Cell Chi-Square ReM FCt cal 1Yea Total 13 Y 12 y 1 1 0.0561 100.00 0 0.0526 0.00 0 'O~'1053 0.00 0 0.0526 0.00 1 2 8 0.0014 80.00 1 0.4263 10.00 0 1.0526 0.00 1 0.4263 10.00 10 3 6 0.0158 75.00 0 0.4211 0.00 2 1.5921 25.00 0 0.4211 0.00 8 15 1 2 1 19 --Total STATISTICSFORTABIEOF SEASON BYAGE statistic Chi-Square Likelihood Ratio Chi-Square Mantel-Haenszel Chi-Square Phi Coefficient COntingency Coefficient cramer's V = DF Value Prob 6 6 1 4.623 6.097 0.212 0.493 0.442 0.349 0.593 0.412 0.645 Sample Size 19 WARNING:83% of the cells have expected counts less than 5. Chi-Square may not be a valid test. �288 Comparison of Age Distribution Across Seasons Cornparison Across 3 Seasons for Elk in ]),t\IJ E-6, 1987, Females 11:05 SUnday, June 19, 1988 TABlE SEASON Frequency Cell <lri -Square Row Pet OF SEASONBY AGE AGE II IYea cal Total 13 Y 12 y -+ 2 33 0.227 10.89 50 0.0027 16 •.50 55 0.0732 18.15 46 0.0145 15.18 303 3 8 0.6489 7.55 17 0.0076 16.04 22 0.2094 20.75 15 0.0414 14.15 106 41 67 77 61 409 Total (Continued) TABLE OF SEASONBY AGE SEASON Frequency Cell Chi -Square Row Pet AGE I I4 Y 15-8 Total 1>8 2 30 0.6391 9.90 65 0.0006 21.45 24 1.0709 7.92 303 3 5 1.827 4.72 23 0.0016 21.70 16 3.0611 15.09 106 35 88 40 409 Total STATISTICSFOR TABlE statistic Chi -Square Likelihcx:x:l Ratio <lri -Square Mantel-Haenszel <lri -Square Phi Coefficient Contingency Coefficient cramer's V Sample Size = 409 OF SEASONBY AGE DF Value Frob 6 6 1 7.825 7.837 2.787 0.138 0.137 0.138 0.251 0.250 0.095 �289 Comparison of Age Distribution Across Seasons Comparison for I.li\U=D-15 & year=1987 & sex=F 11:05 SUnday, June 19, 1988 TABlE OF SEASON BY AGE AGE Frequency cell Chi-Square Row Pet 2 Y 13 Y Total 1>4 14 Y 2 0 0.9 0.00 5 0.0556 55.56 1 0.0111 11.11 3 0.0333 33.33 9 3 1 8.1 100.00 0 0 0.1 0.00 0 0.3 0.00 1 0.5 0.00 1 5 1 3 10 Total STATISl'ICSFOR TABLE OF SEASON BY AGE statistic DF Value Frob 3 1 6.502 2.462 0.090 0.117 0.200 -----------------------------------3 10.000 0.019 Chi-Square LikelihCXJd Ratio Chi-Square Mantel-Haenszel Chi-Square Fisher's Exact Test (2-Tail) :Rrl Coefficient Contingency Coefficient Cramer's V 1.000 0.707 1.000 sample Size = 10 WARNING: 100%of the cells have expected counts less than 5. Chi-Square ma.ynot be a valid test. �290 Comparison of Age Distribution Across Seasons Comparison for ~D-16 & year=1986 & sex=M 11:05 SUnday, June 19, 1988 TABlE OF SEASON BY AGE AGE SEASON Frequency Cell au.-Square Row Pet Yea o 1 2 12 13 Y 14 Y 1 1>4 Y Total -+ o o 0.3415 0.00 0.2439 0.00 0.3415 0.00 2.3439 50.00 ---+ 1 0.2927 0.00 0.2111 50.00 0.5378 50.00 0.2927 0.00 0.6341 0.00 0.5378 50.00 6 12 0.0061 32.43 8 7 4 0.1163 21.62 0.0738 18.92 0.0581 10.81 ----------~------_+------_r------_r------~----___+ o o o 1 3 0.0633 16.22 1 ----------~------_+------_r-------_r----,--~------_+ 10 7 13 Total 5 6 STATISTICS FOR TABLE OF SEASON BY AGE statistic au.-Square Likelihcxxi Ratio au.-Square Mantel-Haenszel Chi-Square Rri Coefficient Contingency Coefficient Cramer's V DF Value Frob 8 8 1 6.095 6.924 0.096 0.386 0.360 0.273 0.637 0.545 0.756 Sample Size = 41 WARNING: 73% of the cells have expected counts less than 5. au.-Square may not be a valid test. 2 2 37 41 �291 CoIrparison of Age Distribution Across Seasons CoIrparison for DAU=D-16 & year=1987 & sex=F 11:05 SUnday, June 19, 1988 TABIEOF SEASON BYAGE SEASON AGE Frequency Cell au.-Square ReM Pet Yea 13 Y 12 y Total 1>4 -+ 2 0 0.6667 0.00 2 0.0667 50.00 2 0.3333 50.00 0 0.3333 0.00 4 3 2 0.3333 25.00 3 0.0333 37.50 2 0.1667 25.00 1 0.1667 12.50 8 2 5 4 1 12 Total STATISTICSFORTABIEOF SEASON BYAGE statistic au. -Square Likelihood Ratio au. -Square Mantel-Haenszel Chl.-Square Fisher's Exact Test (2-Tail) Fbi Coefficient contingency Coefficient cramer's V DF Value Prob 3 3 1 2.100 3.001 0.017 0.552 0.391 0.896 0.838 0.418 0.386 0.418 Sample Size = 12 WARNING: 100% of the cells have expected counts less than 5. Chi-Square may not be a valid test. �292 Comparison of Age Distribution Across Seasons Comparison for I:lrill=D-16 & yea:r=1987 & sex=M 11:05 SUnday, June 19, 1988 TABlEOF SEASON BYAGE SEASON AGE Frequency cell Oli-Square Yea Row Pet 13 Y 12 y Total 1>4 14 Y 1 0 0.0526 0.00 0 0.1579 0.00 0 0.4737 0.00 0 0.1053 0.00 1 2.9605 100.00 2 0 0.1053 0.00 1 1.4825 50.00 1 0.0029 50.00 0 0.2105 0.00 0 0.4211 0.00 3 1 0.0296 6.25 2 0.1096 12.50 8 0.0234 50.00 2 0.0592 12.50 9 '2 1 -+ 2 ----+ 3 0.0403 18.75 16 ---+ Total 1 3 4 STATISTICSFOR TABIEOF SEASON BYAGE statistic Oli-Square Likelihood Ratio Chi-Square Mantel-Haenszel Chi-Square Fisher's Exact Test (2-Tail) Fbi Coefficient Contingency Coefficient Cramer's V DF Value Prob 8 8 1 6.234 5.797 1.093 0.621 0.670 0.296 0.641 0.573 0.497 0.405 Sample Size = 19 WARNING:93% of the cells have expected counts less than 5. Chi-Square may not be a valid test. 19 �293 Comparison of Age Distribution Across seasons Comparison for mU=D-3 & year=1986 & sex=M 11:05 SUnday, June 19, 1988 TABLE OF SEASON BY AGE SEASON AGE Frequency Cell Chi-Square ReMPet 2 Y 13 Y Total 1>4 14 Y 1 5 0.0818 83.33 0 0.4 0.00 0 0.4 0.00 1 0.05 16.67 6 2 3 0.0015 75.00 P 0 0.2667 0.00 1 0.4083 25.00 4 0.2667 0.00 3 0.1212 60.00 1 1.3333 20.00 1 1.3333 20.00 0 0.6667 0.00 11 1 1 2 -t 3 5 -t Total 15 STATISTICSFOR TABLE OF SEASON BY AGE Statistic Chi-Square Likelihocxi Ratio Chi-Square Mantel-Haenszel Chi-Square Fisher's Exact Test (2-Tail) Ihi Coefficient Contingency Coefficient Cramer's V OF Value Frob 6 6 1 5.330 6.307 0.026 0.502 0.390 0.871 0.707 0.596 0.512 0.421 Sample Size = 15 WARNING: 100%of the cells have expected counts less than 5. Chi-Square may not be a valid test. �294 Cc::Irrparisonof Age Distribution Across Seasons Cc::Irrparisonfor DAU=D-31 & year=1986 & sex=M 11:05 SUnday, June 19, 1988 TABIEOF SEASON BY AGE SEASON AGE Frequency Cell ari-Square Yea Row Pet 13 Y 12 y 14 Y Total 1>4 1 0 1.1667 0.00 3 1.1435 14.29 4 0.3081 19.05 4 0.0424 19.05 10 0.0501 47.62 21 2 1 0.4587 2.86 2 0.1916 5.71 6 0.1764 17.14 7 0.0205 20.00 19 0.069 54.29 35 3 4 2.3595 11.76 2 0.157 5.88 3 0.7437 8.82 8 0.0942 23.53 17 0.0082 50.00 34 5 7 13 19 46 ---+ Total STATISTICSFOR TABIEOF SEASON BY AGE statistic ari-Square Likelihood Ratio ari-Square Mantel-Haenszel Chi-Square :R1i.Coefficient Contingency Coefficient Cramer's V = DF Value Frob 8 8 1 6.990 7.564 0.084 0.279 0.268 0.197 0.538 0.477 0.771 Sample Size 90 WARNING:60% of the cells have e:xpected counts less than 5. Chi-Square may not be a valid test. 90 �295 Comparison of Age Distribution Across Seasons Comparison for IYill=D-36 & year=1986 & sex=M 11:05 SUnday, June 19, 1988 TABLEOF SEASON BY AGE SEASON AGE Frequency Cell au.-Square Row Pet Yea 13 Y 12 y Total 1>4 14 Y 0 0.2 0.00 2 2 1 66.67 0 0.8 0.00 1 0.05 33.33 0 0.2 0.00 3 3 3 0.25 25.00 4 0.2 33.33 3 0.0125 25.00 1 0.05 8.33 1 0.05 8.33 12 5 4 4 1 1 15 ----+ Total STATISTICSFORTABIEOF SEASON BYAGE statistic au. -Square Likelihood Ratio au. -Square Mantel-Haenszel au.-Square Fisher's Exact Test (2-Tail) Phi Coefficient Contingency Coefficient Cramer's V DF Value Prob 4 4 1 2.813 3.783 0.735 0.590 0.436 0.391 0.824 0.433 0.397 0.433 Sample Size = 15 WARNING: 100% of the cells have expected counts less than 5. Ori-Square may not be a valid test. �296 Ccln'parison of Age Distribution Across Seasons Ccln'parison for I:Ilill=D-4 & year=1986 & sex=M 11:05 SUnday, June 19, 1988 TABIEOF SEASON BYAGE SEASON AGE Frequency Cell Chi-Square Row Pet Yea 13 Y 12 y Total 1>4 14 Y 1 2 0.0559 50.00 1 0.2344 25.00 1 0.9846 25.00 0 0.1538 0.00 0 0.1538 0.00 2 2 0.4207 66.67 1 0.0369 33.33 0 0.2885 0.00 0 0.1154 0.00 0 0.1154 0.00 3 18 0.0566 40.00 19 0.0376 42.22 4 0.0247 8.89 2 0.0419 4.44 22 21 5 2 4 -+ 3 -+-------+ 2 0.0419 4.44 45 -----+ Total 2 STATIsrICS FOR TABIEOF SEASON BYAGE statistic Chi-Square Likelihood Ratio Chi-Square Mantel-Haenszel Chi-Square !hi Coefficient Contingency Coefficient Cramer's V = DF Value Prob 8 8 1 2.762 3.255 0.398 0.230 0.225 0.163 0.948 0.917 0.528 Sample Size 52 WARNING:87% of the cells have expected counts less than 5 • Chi-Square may not be a valid test. 52 �297 Comparison of Age Distribution Across Seasons Comparison for D.AU=D-7& year=1986 & sex=M 11:05 SUnday, June 19, 1988 TABIEOF SEASON BYAGE SEASON AGE Frequency Cell au-Square ReM Pet Yea Total 13 Y 12 y 1 2 1.6562 10.00 12 0.2648 60.00 6 0.2847 30.00 20 2 2 1.1084 50.00 1 0.5523 25.00 1 0.0012 25.00 4 3 3 2.664 60.00 2 0.1329 40.00 0 1.2069 0.00 5 7 15 7 -+ Total 29 STATISTICSFOR TABIEOF SEASONBYAGE statistic au-Square Likelihood Ratio Chi-Square Mantel-Haenszel au-Square Fisher's Exact Test (2-Tail) :Ehi Coefficient Contin:]ency Coefficient Cramer's V DF Value Prob 4 4 1 7.871 8.610 5.684 0.096 0.072 0.017 7. 64E-02 0.521 0.462 0.368 Sample Size = 29 WARNING:89% of the cells have expected counts less than 5. Ori-Square may not be a valid test. �298 Cclrrparison of Age Distribution Across Seasons Comparison for ~E-13 & year=1987 & sex9M 11:05 SUnday, June 19, 1988 TABIEOF SEASON BYAGE SEASON AGE Frequency Cell Chi-Square ReM Pet cal 1Yea 12 y 2 0 0.4 0.00 1 0.9 100.00 0 0.1 0.00 3 4 0.0444 44.44 ~ 0.1 33.33 0.0111 11.11 4 4 Total Total 13 Y 0 0.1 0.00 1 1 1 9 0.0111 11.11 1 10 1 STATISTICSFOR TABLEOF SEASON BYAGE statistic Chi-Square Likelihocx:i Ratio Chi-Square Mantel-Haenszel Chi-Square Fisher's Exact Test (2-Tail) Fhi Coefficient Contingency Coefficient Cramer's V = DF Value Prob 3 3 1 1.667 2.003 0.011 0.644 0.572 0.916 1.000 0.408 0.378 0.408 Sample Size 10 WARNING: 100% of the cells have expected counts less than 5. Chi-Square nay not be a valid test. �299 Comparison of Age Distribution Across Seasons Gamparison for ~E-16 & year=1987 & sex=F 11:05 SUnday, June 19, 1988 TABLEOF SEASON BYAGE SEASON Frequency cell au.-Square RO'itl Pet Yea 13 Y 12 y 15-8 14 Y 2 2 0.0152 18.18 2 0.0152 18.18 1 0.0076 9.09 1 0.3788 9.09 3 0 0.1667 0.00 0 0.1667 0.00 0 0.0833 0.00 1 4.1667 100.00 2 2 1 2 Total 1>8 ---t-------t 4 1 0.0303 0.0076 36.36 9.09 -----t 0 0 0.3333 0.0833 0.00 0.00 ---t--------t 4 1 STATISTICSFORTABLEOF SEASON BYAGE statistic au. -Square Li.kelihcxxl Ratio au. -Square Mantel-Haenszel Chi-Square Fisher's Exact Test (2-Tail) fhi Coefficient Contingency Coefficient Cramer's V = DF Value Prob 5 5 1 5.455 4.111 0.000 0.363 0.533 1.000 0.667 0.674 0.559 0.674 Sarrple Size 12 WARNING: 100% of the cells have expected courrts less than 5. Chi-Square may not be a valid test. Total 11 1 12 �300 Cc::Irrparisonof Aqe Distribution Across Seasons Cc::Irrparisonfor IlMJ=:E-22 & year=1986 & sex=M 11:05 SUnday, June 19, 1988 TABIEOF SEASON BY AGE SEASON AGE Frequency cell Chi-Square Row Pet Yea 13 Y 12 y Total 15-8 14 Y 2 5 0.0184 50.00 0 0.5882 0.00 4 0.0627 40.00 0 0.5882 0.00 1 0.2882 10.00 10 3 3 0.0263 42.86 1 0.8403 14.29 2 0.0896 28.57 1 0.8403 14.29 0 0.4118 0.00 7 8 1 6 1 --+ Total 1 STATISTICSFORTABlE OF SEASON BYAGE statistic Chi-Square Likelihocx:i Ratio Chi-Square Mantel-Haenszel Chi-Square Fisher's Exact Test (2-Tail) Phi Coefficient Contingency Coefficient Cramer's V DF Value Prob 4 4 1 3.754 4.812 0.008 0.440 0.307 0.928 0.593 0.470 0.425 0.470 Sample Size = 17 WARNING: 100% of the cells have expected counts less than 5. Chi-Square may not be a valid test. 17 �301 Col'rprrison of Age Distribution Across Seasons Col'rprrison for ~E-22 & year=1987 & sex=F 11:05 SUnday, June 19, 1988 'ITffiIEOF SEASON BYAGE SEASON AGE Frequency 1 Cell Ori -Square ReM Pet cal I 1Yea 12 y Total 13 Y -t 2 5 0.1113 8.93 9 0.0172 16.07 15 0.3338 26.79 4 0.6838 7.14 56 3 0 0.6923 0.00 1 0.106~ 11.11 0 2.0769 0.00 3 4.2549 33.33 9 5 10 15 7 65 Total (Continued) TABIEOF SEASON BYAGE SEASON Frequency Cell Ori -Square ReM Pet AGE 1 I4 Y 15-8 Total 1>8 2 6 0.1155 10.71 12 0.0659 21.43 5 0.1113 8.93 56 3 2 0.7188 22.22 3 0.4103 33.33 0 0.6923 0.00 9 8 15 5 65 Total statistic STATISI'ICSFOR TABIEOF SEASON BYAGE DF Value Ori-Square Likelihood Ratio Ori-Square Mantel-Haenszel Ori-Square Ihl. Coefficient Conti.rgency Coefficient Cramer's V = 6 6 1 10.391 12.209 0.296 0.400 0.371 0.400 Frob 0.109 0.057 0.586 Sample Size 65 WARNING:64% of the cells have expected counts less than 5. Ori-Square may not be a valid test. �302 Comparison of Age Distribution Across Seasons Comparison for DMJ=E-22 & year=1987 & sex=M 11:05 SUnday, June 19, 1988 TABIEOF SEASON BYAGE SEASON AGE Frequency 1 Cell au. -Square ReM Pet cal I 1Yea 12 y Total 13 Y 1 0 0.7742 0.00 1 0.1942 12.50 4 0.4751 50.00 1 0.1942 12.50 8 2 3 1.1157 17.65 3 0.025~ 17.65 4 0.6847 23.53 4 0.1531 23.53 17 3 0 0.5806 0.00 2 0.6057 33.33 3 0.3563 50.00 1 0.0224 16.67 6 3 6 11 6 -+ Total (Continued) SEASON Frequency Cell au.-Square ReM Pet AGE 15-8 4 Y Total 1>8 1 1 0.4536 12.50 0 0.2581 0.00 1 0.4536 12.50 8 2 1 0.0085 5.88 1 0.3719 5.88 1 0.0085 5.88 17 3 0 0.3871 0.00 0 0.1935 0.00 0 0.3871 0.00 6 2 1 2 31 Total 31 �303 STATISTICS FOR TABlE OF SEASON BY AGE statistic DF Value Frob Chi-Square Likelihood Ratio Chi-Square Mantel-Haenszel Chi-Square Fisher's Exact Test (2-Tail) :Rri Coefficient Contingency Coefficient Cramer's V 12 12 1 7.704 9.732 1.339 0.808 0.639 0.247 0.907 0.499 0.446 0.353 Sample Size = 31 WARNING: 95%of the cells have expected counts less than 5. Chi-Square may not be a valid test. �304 Comparison of Age Distribution Across Seasons Comparison for DAU=E-25 & year=1987 & sex=F 11:05 SUnday, June 19, 1988 TABIEOF SEASON BYAGE SEASON AGE Frequency 1 Cell Ori -Square ReM Pet cal I 1Yea 12 y 13 'Ibtal Y 2 3 0.0127 11.54 3 0.3773 11.54 4 0.5031 15.38 8 0.1347 30.77 26 3 1 0.0301 9.09 0 0.891~ 0.00 0 1.1892 0.00 2 0.3184 18.18 11 4 3 4 10 -+ 'Ibtal (Continued) SEASON AGE Frequency 1 Cell Ori -Square ReM Pet 4 Y I 15-8 'Ibtal 1>8 2 4 0.0111 15.38 3 1.2226 11.54 1 0.1169 3.85 26 3 2 0.0262 18.18 5 2.8897 45.45 1 0.2764 9.09 11 6 8 2 37 'Ibtal 37 STATISTICSFOR TABIEOF SEASON BYAGE statistic Ori -Square Likelihood Ratio Ori -Square Mantel-Haenszel Ori -Square Fisher's Exact Test (2-Tail) Fbi Coefficient Contingency Coefficient Cramer's V DF 6 6 1 Value 8.000 9.531 3.572 Frob 0.238 0.146 0.059 0.268 0.465 0.422 0.465 Sample Size = 37 WARNING:86% of the cells have expected counts less than 5. Ori-Square may not be a valid test. �305 Comparison of Age Distribution Across Seasons Comparison for IlAU=E-3 & year=1986 & sex=F 11:05 SUnday, June 19, 1988 OF SEASON BY AGE TABIE SEASON Frequency cell Chi-Square Row Pet AGE 1 Ical Total 1 Yea 2 7 0.0234 22.58 3 0.0873 9.68 2 0.6818 6.45 5 0.1978 16.13 31 3 6 0.0242 20.00 4 0.0902 13.33 5 0.7045 16.67 7 30 0.2044 23.33 13 7 7 12 Total (Continued) TABIE SEASON AGE Frequency 1 cell Chi-Square Row Pet 4 Y I OF SEASON BY AGE 15-8 Total 1>8 2 6 0.4447 19.35 5 0.0013 16.13 3 1.4278 9.68 31 3 3 0.4596 10.00 5 0.0014 16.67 0 1.4754 0.00 30 9 10 3 61 Total statistic STATISl'ICSFOR TABIE OF SEASON BY AGE DF Value Chi-Square Likelihood Ratio Chi-Square Mantel-Haenszel Chi-Square !hi Coefficient Contingency Coefficient Cramer's V = 61 6 6 1 5.824 7.045 1.731 0.309 0.295 0.309 Frob 0.443 0.317 0.188 Sample Size 61 WARNING:64% of the cells have expected counts less than 5. Chi-Square may not be a valid test. �306 Comparisonof Age Distribution Across Seasons Comparisonfor Illill=E-32 & year=1986 & sex=M 11:05 SUnday,June 19, 1988 TABlE OF SEASON BY AGE AGE Frequency Cell Chi-Square RowPet Yea Total 13 Y 12 y 1 0 0.8182 0.00 3 0 50.00 3 0.3068 50.00 6 2 1 0.0022 14.29 4 0.0714 57.14 2 0.1169 28.57 7 3 2 0.4865 22.22 4 0.0556 44.44 3 0.0227 33.33 9 3 11 8 22 Total STATISTICS FOR TABIE OF SEASON BY AGE statistic Chi-Square Likelihood Ratio Chi-Square Mantel-Haenszel Chi-Square Fisher's Exact Test (2-Tail) Rri Coefficient Contingency Coefficient Cramer's V DF Value Prob 4 4 1 1.880 2.596 1.049 0.758 0.627 0.306 0.902 0.292 0.281 0.207 Sample Size = 22 100%of the cells have expected counts less than 5. Chi-Square maynot be a valid test. WARNING: �307 Ccln'parison of Age Distribution Across Seasons Ccln'parison for IW.J=E-32 & year=1987 & sex=M 11:05 SUrrlay, June 19, 1988 TABIEOF SEASON BYAGE SEASON AGE Frequency Cell ali-Square Row Pet cal 1Yea 13 Y 12 y Total 14 Y 1 0 0.3529 0.00 0 0.1765 0.00 2 0.0018 66.67 1 3.8431 33.33 0 0.3529 0.00 3 2 2 0.1448 15.38 1 0.0724 7.69 8 0.0202 61.54 0 0.7647 0.00 2 0.1448 15.38 13 3 0 0.1176 0.00 0 0.0588 0.00 1 0.1925 100.00 0 0.0588 0.00 0 0.1176 0.00 1 2 1 11 1 2 17 -+ Total STATIsrrCS FORTABIEOF SEASON BYAGE statistic ali-Square Likelihood Ratio ali-Square Mantel-Haenszel ali-Square Fisher's Exact Test (2-Tail) !hi Coefficient Contingency Coefficient Cramer's V DF Value Frob 8 8 1 6.420 6.339 0.236 0.600 0.609 0.627 0.653 0.615 0.524 0.435 Sample Size = 17 WARNING: 93% of the cells have expected counts less than 5. ali -Square may not be a valid test. . �308 Comparison of Age Distril:ution Across Seasons Comparison for IW.FE-33 & year=1986 & sex=F 11:05 SUnday, June 19, 1988 TABIEOF SEASONBY AGE SEASON Frequency Cell ari.-Square Row R::t AGE Cal 1Yea 13 12 y Total Y 2 0 0.2174 0.00 0 0.4348 0.00 0 1.3043 0.00 1 0.0196 20.00 5 3 2 0.0265 4.88 4 0.053 9.76 12 0.1591 29.27 7 0.0024 17.07 41 2 4 12 8 46 Total (Continued) TABIEOF SEASONBY AGE SEASON Frequency Cell ari. -Square Row R::t I AGE 1 4 Y 15-8 Total 1>8 2 1 1.3928 20.00 2 1.0671 40.00 1 0.0196 20.00 5 3 2 0.1698 4.88 7 0.1301 17.07 7 0.0024 17.07 41 3 9 8 46 Total STATIsrrCS FOR TABIEOF SEASONBYAGE Statistic DF ari.-Square Likelihood Ratio ari. -Square Mantel-Haenszel ari.-Square !hi Coefficient Conti_nJency Coefficient Cramer's V = 6 6 1 Value 4.999 6.217 1.001 0.330 0.313 0.330 Frob 0.544 0.399 0.317 Sample Size 46 WARNING:71% of the cells have expected courrts less than 5. ari.-Square may not be a valid test. �Comparison of Age Distribution Across seasons, Comparison for Dlill=E-33 & year=1986 & sex=M: 11: 05 SUnday, Jrme 19, 19, :' TABIE SEASON OF SEASON BY AGE AGE , Frequency Cell Chi-Square '?n .n: Yea Row Pet , 13 Y 12 y 15c.~ ,. 14 Y : 14 0.3.333 35-~90 Total 1 0 0.4286 0.00 3 1.1868 7.69 10 0.1172 25.64 12 0.4658 30.77 2 0 0.4505 0.00 7 0.223 17.07 13 0.1411 31.71 9 0.1792 21.95 3 1 6.3936 9.09 3 1.2987 27.27 3 0.0065 27.27 2 0.219 18.18 2 0.5664 18.18 11 1 13 26 23 28 91 Total .12 Q,.iJi)3 29'.27 STATISTICSFOR TABIE OF SEASON BYAGE statistic Chi-Square Likelihood Ratio Chi-Square Mantel-Haenszel Chi-Square Rri Coefficient Contin;Jency Coefficient Cramer's V DF Value ~IProb 8 8 1 12.040 9.029 5.406 0.364 0.342 0.257 {O.149 19•340 lID.020 :i ( ( Sample Size = 91 t WARNING:47% of the cells have expected cormts ~ess than 5• Chi-Square may not be a valid t:est. 39 41 �310 Cc::llrparisoft".ofAge Distribution Across seasons CoIrparison for DMJ=E-34 & year=1986' -&_ seX:=F ,'_ 11: 05 Stmday, Jrme 19, 1988 TABIEOF SEMONBY AGE SEASON Frequency Cell Chi-Square RowPet AGE cal Q_ ..- -00.5714 0.,00 2 3 12 1 Yea 2 1.5238 33 •.33 0.2857 0.•00 2 0.2286 : _. 13.33 1 o 0.6095 6.67 15 1 0.1143 6.67 3-- - 1 6 0.2857 0.00 1 0.1143 6.67 Total· _ (Cont.inued) Total Y 21 1 ,'::". .__ TABLE. QF'" SEASON:.. BYAGE:: :" , ~ ' SEASON Frequency Cell Chi-Square RowPet AGE 15-8 4 Y 1 0.0238 16.67 2 Total 1>8 'O;;~~~ --r 1:' 0.2976 16.67 ~ "2 6 -. ~ .. : .' n',' ," ---+ 3 2 0.0095 13.33 Total 5 0.119 33.33 3 15 3 0.0914 ' 20.00_ 6.--- 5 .: 'i,.' 21 '7 ,,- statistic STATISTICSFUR TABIEOF SEASONBYAGE DF" Value Chi-Square Likelihcx:xl Ratio Chi-Square Mantel-Haenszel Chi-Square Fisher's Exact Test (2-Tail) Fbi Coefficient Contingency Coefficient Cramer's V = 6 6 1 4.503 5.352 0.285 - Prob 0.609 0.499 0.594 0.787 0.463 0.420 0.463 Sample Size 21 WARNING: 100% of the cells have expected cormts less than 5. Chi-Square may not be a valid test. �311 comparison of Age Distribution Across Seasons comparison for ~E-34 & year=1986 & ~ 11:05 SUnday, June 19, 1988 TABLEOF SEASON BYAGE SEASON AGE Frequency cell Chi-Square Yea Row Pet 12 y 13 Y 15-8 14 Y Total --+ 2 3 0.7212 33.33 2 0.0083 22.22 2 0.1667 22.22 1 1.0417 11.11 1 1.0417 11.11 9 3 10 0.4327 66.67 3 0.005 20.00 2 0.1 13.33 0 0.625 0.00 0 0.625 0.00 15 13 5 4 1 1 24 Total STATISl'ICSFOR TABIEOF SEASON BYAGE statistic Chi-Square Likelihood Ratio Chi-Square Mantel-Haenszel Chi-Square Fisher's Exact Test (2-Tail) !hi Coefficient Contingency Coefficient Cramer's V DF Value Prob 4 4 1 4.767 5.434 4.188 0.312 0.246 0.041 0.351 0.446 0.407 0.446 San'ple Size = 24 WARNING:90% of the cells have expected counts less than 5 • Chi-Square ma.ynot be a valid test. �312 canparison of Age Distribution Across Season, canparison for I::lAU=E-34 & year=1987 & sex=e 11:05 SUn' :' " TABlE SEASON OFSEASON BY AGE AGE Frequency Cell Chi-Square Row Pet cal 13 Y 15-8 14 Y 1>8 ,,·· .. _·--··'r 2 2 0.0842 22.22 3 1 0.3788 50.00 I 2 3 0.2475 11.11 0.0808 22.22 3 .. 0.1212 33.33 I .,:1.1 I 0 0 0.3636 0.00 0.5455 0.00 0 0.:' tn,S C.OCl r 2 2 3 I , ,..,._.... ",.,."._ + '_ Total , I o. t!,';:·~;4: 1 1.1136 50.00 . .1. '_". I 1 I co.,' ~f' " STATISTICS FOR TABlE OFSEASON BY AGE statistic Chi-Square Likelihood Ratio Chi-Square Mantel-Haenszel Chi-Square Fisher's Exact Test (2-Tail) Ib.i Coefficient ContinJency Coefficient Cramer's V DF Value 4 4 1 3.157 3.839 1.250 ..... , ',0" 0.536 0.472 0.536 Sample Size = 11 WARNING: 100%of the cells have expected counts ] s· :~.,; than 5. Chi-Square may not be a valid i.r:,· '",:~. .', �313 I .._,-, \ .. Comparison of Age Distribution Across Seasons Comparison for ~E-39 & year=1987 & sex=F 11:05 SUnday, June 19, 1988 TABlEOF SEASON BYAGE SEASON Frequency Cell au-Square AGE Rc¥ Pet cal . 2 -f_· =:: ... .0:. ;,')!' 3 \"", Total 13 Y 3 0.1212 11.11 4 0.1616 14.81 4 0.9899 14.81 3 0.1212 11.11 27 0 0.5455 0.00 0 4 0.727,?> 4.4545 0.00 66.67 0 0.5455 0.00 6 3 33 Total~ ...... "; (Continped) 3 '0' r 12 y 1Yea 4 8 TABlEOF SEASON BY AGE SEASON AGE Frequency Cell PJ,j;~Square ReM Pet~,. 4 Y : _,~", 3 Total Total 1>8 .•. \ .••. ..'.~> ~.~. 2 15-8 _. statistic 6 0.2424 22.22 4 0.1684 14.81 3 0.1212 11.11 27 o 2 0.7576 33.33 0 0.5455 0.00 6 1.0909 0.00 6 6 3 33 STATISTICSFOR TABlEOF SEASON BYAGE DF Value au-Square Likelihood Ratio au-Square Mantel-Haenszel au-Square Fisher's Exact Test (2-Tail) Fbi Coefficient Contingency Coefficient Cramer's V = 6 6 1 10.593 12.565 0.141 Frob 0.102 0.050 0.708 0.142 0.567 0.493 0.567 Sample Size 33 WARNING:93% of the cells have expected counts less than 5 • au-Square may not be a valid test. �314 Comparison of Age Distribution Across Seasons Comparison for Dt\U=E-39 & year=1987 & sex=M 11:05 SUnday, June 19, 1988 TABIEOF SEASONBYAGE SFASON' AGE Frequency Cell <lri-Square Row Pet cal 1 2 1Yea 15-8 13 Y 12 y 1>8 0 0.125 0.00 0 0.25 0.00 0 0.75 0.00 1 0.5 50.00 1 2.25 50.00 1 0.142 9.09 2 0.2841 18.18 5 0.1856 45.45 2 0.2045 18.18 1 0.1023 9.09 0 0.1875 0.00 0 0.375 0.00 1 0.0139 33.33 1 0.0833 33.33 0 0.375 0.00 1 2 6 4 2 ------+ 0 Total 2 0.125 0.00 ------+ 0 11 0.6875 0.00 ---+ 3 Total STATISTICSFOR TABLEOF SEASONBYAGE Statistic DF Value Frob ari-Square Likelihood Ratio Chi-Square Mantel-Haenszel <lri-Square Fisher's :Exact Test (2-Tail) Fbi Coefficient Contingency Coefficient Cramer's V 10 10 1 10.162 10.108 0.976 0.426 0.431 0.323 0.551 = 0.797 0.623 0.564 Sample Size 16 WARNING: 100% of the cells have expected courrcs less than 5. Chi-Square may not be a valid test. 1 3.5208 33.33 ----+1 3 16 �315 Corrparison of Age Distribution Across Seasons Comparison for DAU=E-41 & year=1987 & sex=F 11:05 sunday, June 19, 1988 TABlE OF SEASON BYAGE t : SEASON Frequency. Cell au.-Square Row Pet 2 3 AGE cal 1Yea Total 13 Y 12 y 1 0.3682 6.67 3 0.0104 20.00 4 0.2104 26.67 15 0.297 13.33 3 0.3068 16.67 1 0.2475 5.56 4 0.0087 22.22 3 0.1753 16.67 18 4· 3 7 7 33 Total (Continued) 2 " TABLEOF SEASON' BYAGE SEASON Frequency Cell au.-Square Row Pet AGE 4 Y 15~8 Total 1>8 2 0 0.9091, 0.00' 3 0.1114 20.00 2 1.3091 13.33' 15 3 2 0.7576 11.11 5 0.0928 27.78 0 1.0909 0.00 18 2 8 2 33 Total STATISTICSFORTABlEOF SEASONBYAGE statistic au. -Square Likelihcx:d Ratio au. -Square Mantel-Haenszel au. -Square Fisher's Exact Test (2-Tail) Fhi Coefficient Contingency Coefficient Cramer's V DF Value Prob 6 6 1 5.895 7.450 0.801 0.435 0.281 0.371 0.575 0.423 0.389 0.423 Sample Size = 33 WARNING: 100% of the cells have expected counts less than 5. au.-Square may not be a valid test. �316 Ccmprrison of Age Distribution Across Seasons comparison for DAU=E-43 & year=1986 & sex=F 11:05 SUnday, June 19, 1988 TABIEOF SFASONBYAGE SEASON Frequency Cell Chi-Square Row Pet AGE Cal 1Yea 13 12 y Total Y 2 1 0.0833 33.33 1 4.8167 33.33 0 0.75 0.00 0 0.3 0.00 3 3 4 0.0147 23.53 0 0.8~ 0.00 5 0.1324 29.41 2 0.0529 11.76 17 5 1 5 2 20 Total (Continued) TABIEOF SFASONBYAGE SEASON Frequency Cell Chi-Square Row Pet AGE 4 Y 15-8 o 2 0.15 0.00 3 1 0.0265 5.88 Total statistic Total 1>8 o 1 0.2667 33.33 3 0.3 0.00 3 0.0471 17.65 2 0.0529 11.76 17 4 2 20 1 STATISTICSFORTABIEOF SFASONBYAGE DF Value Chi-Square Likelihood Ratio Chi-Square Mantel-Haenszel Chi-Square Fisher's Exact Test (2-Tail) Ihi Coefficient Contingency Coefficient Cramer's V = 6 6 1 7.843 7.406 0.423 Prob 0.250 0.285 0.515 0.430 0.626 0.531 0.626 Sample Size 20 WARNING: 100% of the cells have expected counts less than 5. Chi-Square may not be a valid test. �317 Ccrnparison of Age Distribution Across Seasons Ccrnparison for IYill=E-43 & year=1986 & sex=M 11:05 SUnday, June 19, 1988 TABlEOF SEASON BYAGE SEASON AGE Frequency Cell Chi-Square 12 Yea Row Pet 1 14 Y Total 15-8 Y o 4 0.0289 44.44 2 0.6057 22.22 o 2.0323 0.00 6 2.0157 85.71 0.9032 0.00 2.6544 14.29 8 3.0511 53.33 5 0.7025 33.33 2 0.0022 13.33 o o 0.4839 0.00 0.9677 0.00 9 15 4 1 0.9956 11.11 o 2 3 13 Y Total 0.2903 0.00 2 3.4695 22.22 9 -+ 1 1 o 2 STATISTICSFOR TABIEOF SEASON BYAGE statistic Chi-Square Likelihood Ratio Chi-Square Mantel-Haenszel Chi-Square Fisher's Exact Test (2-'l'ail) fhl Coefficient Contingency Coefficient Cramer's V = 7 0.4516 0.00 OF Value Frob 8 8 1 18.655 20.493 6.980 0.017 0.009 0.008 1. 14E-02 0.776 0.613 0.549 Sample Size 31 WARNING:93% of the cells have expected courrts less than 5. Clri-Square may not be a valid test. 15 31 �318 Corrparison of Age Distribution Across Seasons Corrparison for J:ll!JJ=E-43 & year=1987 & sex==F 11:05 Sunday, June 19, 1988 TABlE OF SEASONBYAGE SEASON Frequency Cell Chi-Square Row Pet AGE cal 1Yea 12 y Total 13 Y 2 5 0.6722 13.89 3 0.4033 8.33 7 0.0417 ·19.44 7 0.0417 19.44 36 3 5 1.7286 35.71 3 1.0371 21.43 2 0.1073 14.29 2 0.1073 14.29 14 10 6 9 9 50 Total (Continued) TABlE OF SEASONBY AGE SEASON Frequency Cell Chi-Square Row Pet AGE 4 Y 15-8 Total 1>8 2 4 0.4356 11.11 6 0.1829 16.67 4 0.0444 11.11 36 3 0 1.12 0.00 1 0.4702 7.14 1 0.1143 7.14 14 4 7 5 50 Total statistic STATISTICSFORTABLEOF SEASONBY AGE DF Value Chi-Square Likelillcx:xi Ratio Chi-Square Mantel-Haenszel Chi-Square Fhi. Coefficient Contingency Coefficient Cramer's V 6 6 1 6.507 7.300 2.911 0.361 0.339 0.361 Frob 0.369 0.294 0.088 Sample Size = 50 WARNING:71% of the cells have expected counts less than 5. Chi-Square may not be a valid test. �319 Comparison of Age Distribution Across Seasons Comparison for ~E-43 & year=1987 & sex=M 11:05 SUnday, June 19, 1988 TABIEOF SEASON BY AGE SEASON AGE Frequency Cell <lrl-Square Row Pet cal 1Yea 12 y Total 13 Y 2 2 0.0182 40.00 1 0.7127 20.00 1 0.6545 20.00 1 0.6545 20.00 5 3 2 0.0152 33.33 ~ 0.5939 66.67 0 0.5455 0.00 0 0.5455 0.00 6 4 5 1 1 11 Total STATISl'ICSFOR TABIEOF SEASON BYAGE statistic Clri-Square Likelihood Ratio <lrl-Square Mantel-Haenszel Chi-Square Fisher's Exact Test (2-'l'ail) Fbi Coefficient Contingency Coefficient Cramer's V DF Value Frob 3 3 1 3.740 4.609 0.871 0.291 0.203 0.351 0.264 0.583 0.504 0.583 Sample Size = 11 WARNING: 100%of the cells have expected counts less than 5 • Chi-Square may not be a valid test. �320 Comparison of Aqe Distribution Across Seasons Comparison for I:li\U=E-6 & year=1986 & sex=F 11:05 SUnday, June 19, 1988 TABIE OF SEASONBYAGE SEASON Frequency Cell au.-Square RcM~ AGE cal 1Yea 13 12 y Total Y 2 11 2.4985 22.45 10 1.4373 20.41 8 0.0131 16.33 7 0.09 14.29 49 3 3 2.4005 5.88 4 1.3809 7.84 9 0.0126 17.65 9 0.0865 17.65 51 14 14 17 16 100 Total (Continued) TABIE OF SEASONBYAGE SEASON Frequency Cell au.-Square RcM~ 2 3 Total statistic AGE 4 Y 15-8 Total 1>8 3 0.0539 6.12 9 0.4572 18.37 1 2.6368 2.04 49 4 0.0518 7.84 14 0.4393 27.45 8 2.5334 15.69 51 7 23 9 100 .... STATISTICSFOR TABIE OF SEASONBYAGE OF Value au. -Square Likelihood Ratio Chi -Square Mantel-Haenszel au. -Square Rrl Coefficient Contingency Coefficient Cramer's V 6 6 1 14.092 15.223 12.298 0.375 0.351 0.375 Prob 0.029 0.019 0.000 Sample Size = 100 WARNING:29% of the cells have expected COlIDts less than 5. Chi-Square may not be a valid test. �321 Comparison of Age Distribution Across Seasons Oornparison for DAU=E-6 & year=1986 & sex=M 11:05 SUnday, June 19, 1988 TABIE OF SEASON BY AGE SEASON AGE Frequency Cell au.-Square Row Pet Yea o 1 1.6949 0.00 2 3 1.5256 13.64 3 13 12 Y 23 1.0177 92.00 17 0.0214 77.27 Y 1>8 15-8 14 Y Total 2 o o o 0.0066 8.00 0.8475 0.00 0.8475 0.00 0.8475 0.00 1 0.4008 4.55 1 0.0867 4.55 o 0.7458 0.00 --+ o 4 2 2 2 2.737 33.33 0.9503 16.67 0.8651 8.33 6.2401 16.67 6.2401 16.67 4 44 5 2 2 1 22 0.7458 0.00 ----+ 0.0427 8.33 1 25 12 -+-----+ Total STATISTICS FOR TABIE OF SEASON BY AGE statistic DF Value Prob au. -Square Likelihood Ratio au. -Square Mantel-Haenszel au. -Square Phi Coefficient Contingency Coefficient Cramer's V 10 10 1 25.863 25.385 10.881 0.662 0.552 0.468 0.004 0.005 0.001 Sample Size = 59 WARNING: 83% of the cells have expected counts less than 5. au.-Square may not be a valid test. 2 59 �322 Cclrrparisonof Age Distribution Across Seasons Cclrrparisonfor Jl.lill=E-6 & year=1987 & sex=F 11:05 SUnday, June 19, 1988 TABIE OF SFASON BY AGE SEASON AGE Frequency Cell au.-Square RaN Pet cal 1Yea Total 13 Y 12 y 2 33 0.8392 10.89 50 0.3832 16.50 55 0.0071 18.15 46 0.0505 15.18 303 3 8 0.3456 7.55 17 0.0592 16.0:4 22 0.3315 20.75 15 0.0207 14.15 106 4 2 1.8127 3.70 3 3.2665 5.56 8 0.3694 14.81 7 0.1093 12.96 54 43 70 85 68 463 Total (Continued) SEASON AGE Frequency Cell au.-Square ReM Pet 4 Y 15-8 Total 1>8 2 30 0.7854 9.90 65 0.4562 21.45 24 2.3246 7.92 303 3 5 1.7287 4.72 23 0.1204 21.70 16 1.8109 15.09 106 4 4 0.0662 7.41 20 4.3519 37.04 10 2.9797 18.52 54 39 108 50 463 Total STATISI'ICS FOR TABLE OF SFASON BY AGE statistic DF Value Frob --------------------- --------------------22.219 0.035 12 au.-Square Likelihcxxi Ratio au.-Square Mantel-Haenszel au.-Square fbi Coefficient Contingency Coefficient Cramer's V Sample Size = 463 12 1 22.946 14.244 0.219 0.214 0.155 0.028 0.000 �323 Cclrrparison of Age Distribution Across Seasons Cclrrparison for D.2ill=E-6 & year=1987 & sex=M 11:05 SUnday, June 19, 1988 TABIEOF SEASON BY AGE SEASON AGE Frequency Cell Chi-Square Row Pet cal 1Yea Total 13 Y 12 y 1 1 0.05 100.00 0 0.05 0.00 0 0.1 0.00 0 0.05 0.00 1 2 8 0 80.00 1 0.5 10.00 0 1 0.00 1 0.5 10.00 10 3 6 0.025 75.00 0 0.4 0.00 2 1.8 25.00 0 0.4 0.00 8 4 1 0.05 100.00 0 0.05 0.00 0 0.1 0.00 0 0.05 0.00 1 16 1 2 1 20 Total STATISTICSFOR TABLEOF SEASON BYAGE statistic Chi-Square Likelihood Ratio Chi-Square Mantel-Haensz~l Chi-Square Fisher's Exact Test (2-Tail) Fhi. Coefficient Contingency Coefficient Cramer's V = DF Value Frob 9 9 1 5.125 6.556 0.023 0.823 0.683 0.880 0.571 0.506 0.452 0.292 Sample Size 20 WARNING:88% of the cells have expected counts less than 5. Chi-Square may not be a valid test. �324 Cclrrparison of Age Distribution Across Seasons .. COrrparison Across Seasons for Deer with all Di\Us 11:05 SUnday, June 19, 1988 -------- SPECIES=Deer YEAR=1986SEX=F---------TABIEOF SFASONBYAGE SEASON AGE Frequency Cell Chi-Square Row Pet Faw 1Yea 13 Y 12 y 1>4 14 Y --------+ 2 8 0.3208 23.53 8 1.372 23.53 6 0.0463 17.65 4 0.4644 11.76 4 0.0943 11.76 3 13 0.1454 17.33 9 0.622 12.00 15 0.021 20.00 14 0.2105 18.67 21 17 21 18 Total 4 0.993 11.76 34 7 0.0427 9.33 17 0.4502 22.67 75 11 21 109 STATISTICSFORTABLEOF SFASONBYAGE statistic Chi-Square Likelihcxrl Ratio au-Square Mantel-Haenszel Chi-Square Rri Coefficient Contingency Coefficient cramer's V Sample Size = 109 Total DF Value Frob 5 5 1 4.782 4.812 2.602 0.209 0.205 0.209 0.443 0.439 0.107 ------+ ----+ �325 Ccarparison of Age Distribution Across Seasons Ccarparison Across Seasons for Deer with all Di\IJs 11:05 SUnday, June 19, 1988 ------- SPECIES=DeerYFAR=1986SEX=M-------------TABlEOF SEASON BYAGE SEASON AGE Frequency Cell Chi-Square Row 'Pet Yea 12 Y 13 Y 14 Y 1>4 Total 8 1.525 11.94 26 0.7539 38.81 16 1.0872 23.88 5 1.3739 7.46 12 218E-8 17.91 67 2 19 0.8227 14.96 38 0.3075 29.92 27 0.5584 21.26 18 0.273 14.17 25 0.2253 19.69 127 3 45 2.0979 22.84 64 0.0037 32.49 29 1.4594 14.72 26 0.0697 13.20 33 197 0.1459 16.75 1 -~------+-------+-----~------+ 72 128 72 49 70 Total STATISTICSFORTABlEOF SEASON BYAGE statistic Chi-Square Likelihood Ratio Chi-Square Mantel-Haenszel Chi-Square !hi Coefficient Contingency Coefficient Cramer's V Sample Size = 391 DF Value Frob 8 8 1 10.704 11.002 1.113 0.165 0.163 0.117 0.219 0.202 0.292 391 �326 Comparison of Age Distribution Across Seasons -.Comparison Across Seasons for Deer with all DAUs 11:05 SUnday, June 19, 1988 ,-------- SPECIES=DeerYFAR=1987 SEX=F---------TABIEOF SEASON BYAGE SEASON AGE Frequency Cell au.-Square Row Pet Faw 1Yea 12 y 13 Y Total 1>4 14 Y -----+ 2 0 0.6154 0.00 0 1.2308 0.00 6 1.1308 18.75 13 1.0102 40.63 3 0.1178 9.38 3 1 0.9846 5.00 2 1.9692 10.00 9 1.8092 45.00 3 1.6163 15.00 1 0.1885 5.00 4 0.356 20.00 20 1 2 15 16 4 14 52 10 0.2225 31.25 32 ----+ Total STATISTICSFOR TABIEOF SEASON BYAGE statistic au. -Square Likelihood Ratio au-Square Mantel-Haenszel au -Square :Rri Coefficient Contingency Coefficient Cramer's V OF Value Prob 5 5 1 11.251 12.410 5.412 0.465 0.422 0.465 0.047 0.030 0.020 Sample Size = 52 'WARNING: 50% of the cells have expected counts less than 5. au-Square may not be a valid test. �-.:r< ~_;: ..~.'-~~', (~~~':'~~~~;., (~:~i;1~(:,'J;~~:'~.~ ':_:.;,~: :.r\ {f- '"i ..;.' /:r::~.~ ",~:~,~::: -' "~'~ '.. ' . <' I H • ;I{", ,_,.. •. tc -_ , . t.. ;\~ .. ;( . 1.;' ~i~ .. 'f I, - .•..•... '~.•• f;.;_.... -'.",,·.·,.~- •.. ..- .. t:~.""" ... 01'. ~.16/). i I C.!._·d 7.69 .1i ~-.. ~ 0.~~9~i. \ ~,:·._.5~ '~ :'1 t . ;:;..538 23r>()8 ..___~ ,,) o. \J6'.:' G 2,(:: .;!,,:' :':.;~,: ~ =, .1 j --.~-~,--i--...,',"'--'-"""'"';'" - -r: ") 1..) 0,,5766- J..:~:..o. 0.00 ..:. ... .•,.•.......•...•.. ~"" ... , ..•.. l .....•.. ',' " ',._ .. c- ....,:: ..•.. .,:: " J.., ~)7T 2<-94 1,.·:'{::5~~' O~~'Lj,,,~'I fl." .~_':~~~: i' i ,; n 2'g.41! I 2S;,,4:'. I ,.''''-'.-...,-+--_. _,_."....,+,. 'j;:1. ,,- • 0 • -. 9 :2:), 25· _. "", V~L.UC C~.13·--(~(1·O::.:L~(~ ]~.Jk:2.1~;l1-·:~:r_;'_~-~i·,'1_;;t.. ~j:~·_:~;t l~_';~_'·~:;·~~C~ll~~::~.:! ft,;_:~.·i;·':'~:;~~. '-}~:lt:!,n£~~et ..v:( '.(jj.~...Gtfi_.k·.j..l "',:: i:.·· h,l, ('!..''y.;;,:ff ·~.\.·.!it:n~·:: (!r}rlt:irB'e~r(:~ ~ (1;':?;f\~j_,,~:i-f~.{It~ .,:... c.~jT"t:'J.:"'t'!~\7 Sa!nr:}lt~~'~ .sj..~:..:~ :;';:'11.:' tb2 c:e~:.:tS hiiV,,,, e:'\.3:'y?'G"'~Xi C'::. ,-Int,:;: Less (~hj_--S(:r~a"rf~' '_'."~'::;;,z a ··'/3.1~·_a t.(~.t.;. t-l1D"."1 50 '.;,' ~':i-' ,~_ I ~'T?"::~'m~:;: ::.')6\ o:f' ._. 'i. z- �328 Corrparison of Age Distribution Across Seasons Corrparison Across 4 Seasons for Elk with all D.MJs 11:05 SUnday, Jrme 19, 1988 -------------- SPECIES=ElkYFAR=1986 SEX=F------TABlE SEASON AGE Frequency Cell Chi-Square Cal RCM Pet OF SEASON BYAGE IYea 12 y Total 13 Y 2 42 4.2613 19.53 . ~29· 31 0.7104 0.3415 13.49 14.42 26 1.6092 ·12.09 215 3 25 3.5789 9.77 28 0.2868 10.94 48 0.5967 18.75 47 1.3515 18.36 256 67 57 79 73 471 Total (Continued) TABLE SEASON AGE Frequency Cell Chi-Square Row Pet 4 Y OF SEASON BYAGE 15-8 Total 1>8 2 24 0.4292 11.16 44 0.0121 20.47 19 0.787 8.84 215 3 22 0.3605 8.59 54 0.0101 21.09 32 0.6609 12.50 256 46 98 51 471 Total STATISTICSFOR TABLE OF SEASON BY AGE statistic Chi-Square Likelihcxxl Ratio au-Square Mantel-Haenszel Chi-Square !hi Coefficient Contingency Coefficient Cramer's V Sample Size = 471 DF Value Prob 6 6 14.996 15.079 4.513 0.178 0.176 0.178 0.020 0.020 0.034 1 �329 Corrparison of Age Distribution .Across Seasons Comparison.Across 4 Seasons for Elk with all Di\Us 11:05 SUnday, June 19, 1988 -------- SPECIES=Elk YFAR=1986 SEX=M ------------TABIE OF SEASON BY AGE SEASON AGE Frequency Cell Chi-Square Row Pet Yea 1>8 12 y 14 Y 15-8 13 Y -----0 6 20 14 17 1 33 7.9007 105E-7 0.1848 1.5411 4.287 0.559 22.22 15.56 18.89 0.00 6.67 36.67 -----0 28 14 14 2 20 49 0.9447 0.2225 0.3034 442E-7 0.0092 0.7764 16.00 22.40 11.20 11.20 0.00 39.20 Total 90 125 --I- 3 38 13.165 35.51 36 0.263 33.64 17 0.9794 15.89 8 1.3127 7.48 6 3.223 5.61 2 2.6833 1.87 64 118 65 36 37 2 ------ 107 -+ Total STATISTICS FOR TABIE OF SEASON BY AGE statistic DF Value Prob Ori -Square Likelihocxi Ratio Ori-Square Mantel-Haenszel Ori-Square Fbi Coefficient Contingency Coefficient Cramer's V 10 10 1 38.356 39.184 14.923 0.345 0.326 0.244 0.000 0.000 0.000 Sample Size = 322 322 �( . >:-. ~ . f' . _\; I.;' ,~.:/. .:~.', f'~'~ 0\ " r ., '. ....•. :, ". t.~:" •...~ ..·-···-''''····.,..····.....,·'' ••..•. ·~t ~-, ", e· ., (>~~. ~."~?~ ., 11.,0': .'",. -'-, ...;.- ,,, ~"""""'" .•...•••........ ~~ ".. .•.... .: F~·-} ~.~ ... .. ..... ~~ .....•.. 1:' ,~ , ,.'. (}. ". ... .... " () .~-•.. - f~'L " . :.)~:.:, '):,'.: - , - •• r . l..: :' ~ ••••".- •.. """t' . ,. 3f '.~. ••.~\,1 . .-~ ::.L·.< ~-- • r"" •...,.. ---- ....•..-~. , " . ,~, .•.. ·rr i .•.:' •... ," ..,-+- ,. ~~.~•••- .:. J.:}:L ((: ",:.·i~.:.5"\ll7C:.~' t-.\ !'.t·:1,t .,..11C;·'· c-: I. '~·:tj_-~·qu<:rre I l~ ..'•....• ".•... ,•• ' ...L... r ..! , ,. ~) . /;,f; ;.:' lO_C~;; '.; .. '/) _ i I. :~ ..;:: 0;.. "/8::~1. .. ..•...• ,... ",.0 . ,_,_" ...•.. ," -" ~-~7A~. .. ..•. ,_,,'", , ,4;;, ....~,.52 '" .-.~ ..-+. . .:.~ 77 ~ .J 1'.~.'"'{) ..f ),':'~ ~(;,;-) ::'..":'~,·~·~:·~.·~;.3:,:~:~_.: I<.-::/:.J,o , . 7S:J ..:i �331 ..,.jf._. :", .. Cc:atparisoh 'of ,Age Distribution AcrosS, SeiasOns. Coniparison Aci"oss '4. Seasons for Elk With al;l'-mus . ..' l··./..... 11:05 SUnday, Jm.te 1~! ~9~~, > • ,.., SPECIES=Elk YEAR=1987SEX::::M ----------:. TABlE OF SEASON BY AGE AGE SFASON Frequency L; _ Cell·.Chi -Square Row Pet ..,.. .; .(j_r ).~t. call ._ . . _..>--., _. "''' ..-.. , I- " : .J flO rl Yea _. • - :~~ 1 ';2,'; i' 12 .Y r! ~.i13 I Y ; Total 1 - 85 2 . .. . \ .. ,46 .' U' 3 ~..... .. o o 4 0.18 ,:.<~.OO ,0.3 0 . 0.16'. ,;-<~;b.oo \( '~~~.oo' ,) Total .'(~':c (Continued) s : •..•.•••.• .. ", "~~'~-,...•. . :, 150 t " • :-:~••.I -.. - ..• -:.~ " .- .' ..' c']-.I·" �332 Cc:IJ:rparisonof Age Distribution Across seasons Cc:IJ:rparisonAcross 4 seasons for Elk with all DAUs 11:05 SUnday, June 19, 1988 --------- SPECIES=ElkYFAR=1987 SEX=M -------------TABlE OF SEASON BY AGE AGE Frequency Cell Ori-Square RowPet 4 Y 15-8 Total 1>8 1 1 0.0333 5.56 1 0.1089 5.56 1 1.1378 5.56 18 2 8 0.9608 9.41 4 0.1059 4.71 1 0.2882 1.18 85 3 1 1.3928 2.17 1 0.3835 2.17 1 0.007 2.17 46 4 0 0.0667 0.00 0 0.04 0.00 0 0.02 0.00 10 6 3 Total STATISTICS Ori-Square Likelihood Ratio Ori-Square . Mantel-Haenszel Ori-Square Fbi Coefficient Contingency Coefficient Cramer's V Sample Size 150 FOR TABLE OF SEASON BY AGE statistic WARNING: 1 DF Value Frob 18 18 26.717 27.090 10.413 0.422 0.389 0.244 0.084 0.077 0.001 1 = 150 64% of the cells have expected counts less than 5. Ori-Square may not be a valid test. �333 CoIrparison of Age Distribution Across Seasons CoIrparison Across 3 Seasons for Elk with all DAUs 11:05 SUnday, June 19, 1988 ------- SPECIES=ElkYFAR=1986 SEX=F--------TAmE OF SEASON BYAGE SEASON AGE Frequency Cell Chi-Square Row Pet Cal 1Yea 12 y Total 13 Y 2 42 4.2613 19.53 29 0.3415 13.49 31 0.7104 14.42 26 1.6092 12.09 215 3 25 3.5789 9.77 28 0.2868 10.94 48 0.5967 18.75 47 1.3515 18.36 256 67 57 79 73 471 Total (Continued) TABIEOF SEASON BY AGE SEASON AGE Frequency Cell Chi-Square Row Pet 4 Y 15-8 Total 1>8 2 24 0.4292 11.16 44 0.0121 20.47 19 0.787 8.84 215 3 22 0.3605 8.59 54 0.0101 21.09 32 0.6609 12.50 256 46 98 51 471 Total STATIsrICS FOR TAmE OF SEASON BYAGE statistic Chi-Square Likelihocd Ratio Chi-Square Mantel-Haenszel Chi-Square Ihi Coefficient Contingency Coefficient Cramer's V Sample Size = 471 DF Value Frob 6 6 14.996 15.079 4.513 0.178 0.176 0.178 0.020 0.020 0.034 1 �334 Corrparison of Age Distribution Across Seasons Corrparison Across 3 Seasons for Elk with all Di\Us 11:05 SUnday, June 19, 1988 --------------- SPECIES=Elk YEAR=1986 SEX=M --------, TABlE OF SEASON BY AGE AGE Frequency Cell Chi-Square Yea Row Pet 13 Y 12 y 15-8 14 Y 1 Total 1>8 --t 1 6 7.9007 6.67 33 105E-7 36.67 20 0.1848 22.22 14 1.5411 15.56 17 4.287 18.89 2 20 0.9447 16.00 49 0.2225 39.20 28 0.3034 22.40 14 442E-7 11.20 14 0.0092 11.20 0 0.7764 0.00 3 38 13.165 35.51 36 0.263 33.64 17 0.9794 15.89 8 1.3127 7.48 6 3.223 5.61 2 2.6833 1.87 64 118 65 36 37 2 0 0.559 0.00 90 --t- 125 -t- 107 -t- Total STATISTICS FOR TABLE OF SEASON BY AGE statistic DF Value Frob Chi-Square Likelihood Ratio Chi-Square Mantel-Haenszel Chi-Square Fhi Coefficient Contingency Coefficient Cramer's V 10 10 1 38.356 39.184 14.923 0.345 0.326 0.244 0.000 0.000 0.000 Sample Size = 322 322 �335 canparison of Age Distribution Across Seasons canparison Across 3 Seasons for Elk with all I::lA.Us 11:05 SUnday, June 19, 1988 -------- SPECIES=ElkYFAR=1987 SEX=F---------------TABlEOF SEASON BY AGE SEASON AGE Frequency Cell ari-Square Row Pet cal 1Yea 12 y 'Ibtal 13 Y 2 61 0.0247 11.05 83 0.062 15.0~ 104 0.0007 18.84 87 0.0011 15.76 552 3 23 0.0705 11.92 26 0.1773 13.47 36 0.002 18.65 30 0.0032 15.54 193 84 109 140 117 745 'Ibtal (Continued) TABlEOF SEASONBYAGE SFASON Frequency Cell ari-Square Row Pet AGE 4 Y 15-8 'Ibtal 1>8 2 59 0.3172 10.69 110 0.1477 19.93 48 0.0544 8.70 552 3 15 0.9073 7.77 44 0.4223 22.80 19 0.1555 9.84 193 74 154 67 745 'Ibtal STATISTICSFOR TABlEOF SEASONBYAGE statistic Clri-Square Likelihood Ratio ari-Square Mantel-Haenszel ari-Square Rri Coefficient Contingency Coefficient Cramer's V Sample Size = 745 DF Value Prob 6 6 2.346 2.399 0.264 0.056 0.056 0.056 0.885 0.880 0.608 1 �336 Comparison of Age Distribution Across Seasons Comparison Across 3 Seasons for Elk with all I:li\Us 11:05 Sunday, JlU1e 19, 1988 SPECIES=ElkYFAR=1987 SEX=M TABlEOF SEASON BYAGE AGE SEASON Frequency Cell Chl-Square ReM Pet Cal Total 1Yea 12 y 13 Y 1 1 2.3508 5.56 1 1.5683 5.56 8 1.2091 44.44 5 1.522 27.78 18 2 18 0.1005 21.18 11 1.2585 12.94 29 0.4317 34.12 14 0.007 16.47 85 3 15 1.9321 32.61 15 5.3283 32.61 8 2.4994 17.39 5 0.7835 10.87 46 45 24 149 Total (Continued) Frequency Cell Chl-Square ReM Pet 4 Y 34 27. 15-8 Total 1>8 1 1 0.0358 5.56 1 0.1045 5.56 1 1.1217 5.56 18 2 8 0.9235 9.41 4 0.0973 4.71 1 0.2957 1.18 85 3 1 1.4112 2.17 1 0.3922 2.17 1 0.0059 2.17 46 10 6 3 149 Total statistic STATISTICSFORTABlEOF SEASON BYAGE DF Value Prob Chl-Square 23.379 12 0.025 Likelihood Ratio Chl-Square 12 24.158 0.019 0.002 Mantel-Haenszel .Chl-square 1 9.321 0.396 Fhi Coefficient Contingency Coefficient 0.368 0.280 cramer's V Sample Size = 149 WARNING: 52% of the cells have expected counts less than 5. Chl-Square may not be a valid test. �337 NOTE: Copyright(c) 1985,86,87 SAS Institute Inc., Cary, NC 27512-8000, U.S.A. NOTE: SAS (r) Proprietary Software Release 6.03 Licensed to COLORADO STATE UNIVERSITY, Site 09521001. NOTE: OM statements are only valid in OMS ~ode. NOTE: AUTOEXEC processing completed. 1 2 3 4 5 title 'Comparison of Age Distribution Across Seasons'; libname library' .'; proc dbf db3=tooth out=library.tooth; 6 proc format library=library; NOTE: 2561 observations written to the output SAS data set. NOTE: The PROCEDURE DBF used 20.00 seconds. 7 value elkfmt O='Calf' 8 1='Yearling' 9 2='2 years' 10 3='3 years' 11 4='4 years' 12 5-8='5-8 years' 13 9-high='>8 years'; NOTE: Format ELKFMT has been output. 14 value deerfmt O='Fawn' 15 1='Yearling' 16 2='2 years' 17 3='3 years' 18 4='4 years' 19 5-high='>4 years'; ~OTE: Format DEERFMT has been output. 20 21 data valid; NOTE: The PROCEDURE FORMAT used 14.00 seconds. 22 set library.tooth; 23 if sexA=' '; 24 if seasonA=' '; 25 if sex='F' & season='I' then delete; 26 27 proc sort; ~OTE: The data set WORK. VALID has 2405 observations and 7 variables. 10TE: The DATA statement used 30.00 seconds. 28 by dau gmu year sex season~ 29 30 proc means maxdec=O min max; :OTE: The data set WORK. VALID has 2405 observations and 7 variables. 10TE: The PROCEDURE SORT used 25.00 seconds. 31 class dau gmu year sex season; 32 var age; 33 title2 'Number of Animals by GMU'; 34 35 proc sort; :OTE: The PROCEDURE MEANS used 1.03 minutes. 36 by dau year sex season; 37 38 proc means maxdec=O min max; OTE: The data set WORK. VALID has 2405 observations and 7 variables. 'OTE: The PROCEDURE SORT used 25.00 seconds. 39 class dau year sex season; 40 var age; 41 title2 'Number of Animals by DAU'; �3.38 42 43 proc sort; NOTE: The PROCEDURE MEANS used 48.00 seconds. 44 by species year sex season; 45 . 46 proc freq; NOTE: The data set WORK. VALID has 2405 observations and 7 variables. NOTE: The PROCEDURE SORT used 25.00 seconds. 47 by species year; 48 tables age; 49 tit1e2 'Distribution of Animals by Age'; 50 51 proc sort; NOTE: The PROCEDURE FREQ used 36.00 seconds. 52 by dau year sex season; 53 54 proc freq; NOTE: The data set WORK. VALID has 2405 observations and 7 variables. NOTE: The PROCEDURE SORT used 25.00 seconds. 55 where dau='E-6' & year='1987' & sex='M' & seasonA='4'; 56 tables season*age / chisq ce11chi2 nopercent noco1; 57 format age e1kfmt.; 58 tit1e2 'Comparison Across 3 Seasons for Elk in DAU E-6, 1987, Males' ; 59 60 proc freq; NOTE: The PROCEDURE FREQ used 36.00 seconds. 61 where dau='E-6' & year='1987' & sex='F' & seasonA='4'; 62 tables season*age / chisq ce11chi2 nopercent noco1; 63 format age e1kfmt.; 64 title2 'Comparison Across 3 Seasons for Elk in DAU E-6, 1987, Females'; 65 66 data compare; ~OTE: The PROCEDURE FREQ used 37.00 seconds. 67 set valid; 68 by dau year sex; 69 file 'temp.sas'; 70 retain nseason nrecs; 71 drop nseason nrecs; 72 if first. sex then do; 73 nseason=O; 74 nrecs=O; 75 end; 76 nrecs=nrecs+l; 77 if lag(season) A= season then nseason=nseason+1; 78 if last.sex then do; 79 if nrecs >= nseason*5 & nseason > 1 then do; 80 put "proc freq;"; 81 put" where dau='" dau ", & year='" year ", & sex='" .ex"';"; 82 if nrecs > 40 then 83 put" tables season*age / chisq ce1lchi2 nopercent oco 1 ; " ; 84 else 85 put " tables season*age / chisq exact ce11chi2 .opercent noco 1 ; " ; 86 if species="Deer" then 87 put" format age deerfmt.;"; 88 else put" format age e1kfmt.;"; �339 put" title2 'Comparison for DAU=" dau " & year=" year" 89 & sex=" sex"';"; 90 end; 91 end; 92 run; NOtE: The file 'temp.sas' is file C:\CDOW\TOOTH\TEMP.SAS. NOTE: 170 records were written to the file C:\CDOW\TOOTH\TEMP.SAS. The minimum record length was 10. The maximum record length was 60. NOTE: The data set WORK.COMPARE has 2405 observations and 7 variables. NOTE: The DATA statement used 42.00 seconds. 93 94 %include 'temp.sas'; NOTE: The PROCEDURE FREQ used 3S.00 seconds. NOTE: The PROCEDURE FREQ used 33.00 seconds. NOTE: The PROCEDURE FREQ used 34.00 seconds. NOTE: The PROCEDURE FREQ used 3S.00 seconds. NOTE: The PROCEDURE FREQ used 3S.00 seconds. NOTE: The PROCEDURE FREQ used 33.00 seconds. NOTE: The PROCEDURE FREQ used 34.00 seconds. NOTE: The PROCEDURE FREQ used 33.00 seconds. NOTE: The PROCEDURE FREQ used 36.00 seconds. NOTE: The PROCEDURE FREQ used 34.00 seconds. NOTE: The PROCEDURE FREQ used 35.00 seconds. NOTE: The PROCEDURE FREQ used 3S.00 seconds. NOTE: The PROCEDURE FREQ used 34.00 seconds. NOTE: The PROCEDURE FREQ used SO.OO seconds. NOTE: The PROCEDURE FREQ used 44.00 seconds. NOTE: The PROCEDURE FREQ used 34.00 seconds. NOTE: The PROCEDURE FREQ used 36.00 seconds. NOTE: The PROCEDURE FREQ used 3S.00 seconds. NOTE: The PROCEDURE FREQ used 34.00 seconds. NOTE: The PROCEDURE FREQ used 33.00 seconds. NOTE: The PROCEDURE FREQ used 36.00 seconds. NOTE: The PROCEDURE FREQ used 34.00 seconds. ~OTE: The PROCEDURE FREQ used 34.00 seconds. ~OTE: The PROCEDURE FREQ used 37.00 seconds. ~OTE: The PROCEDURE FREQ used 35.00 seconds. ~OTE: The PROCEDURE FREQ used 42.00 seconds. ~OTE: The PROCEDURE FREQ used 36.00 seconds. 'IOTE:The PROCEDURE FREQ used 41.00 seconds. 10TE: The PROCEDURE FREQ used 33.00 seconds. 10TE: The PROCEDURE FREQ used 34.00 seconds. lOTE: The PROCEDURE FREQ used 34.00 seconds. 10TE: The PROCEDURE FREQ used 33.00 seconds. 10TE: The PROCEDURE FREQ used 36.00 seconds. 265 266 proc sort; :OTE: The PROCEDURE FREQ used 35.00 seconds. 267 by species year sex season; 268 269 proc freq; ;OTE: The data set WORK.COMPARE has 2405 observations and 7 variables. :OTE: The PROCEDURE SORT used 27.00 seconds. 270 where spec;es='Deer'; 271 by species year sex; 272 tables season*age / chisq cellchi2 nopercent nocol; 273 format age deerfmt.; 274 title2 'Comparison Across Seasons for Deer with all DAUs'; 275 �340 276 NOTE: 277 278 279 280 281 282 283 NOTE: 284 285 286 287 288 289 290 NOTE: NOTE: proc freq; The PROCEDURE FREQ used 52.00 seconds. where species='Elk '; by species year sex; tables season*age I chisq cellchi2 nopercent nocol; format age elkfmt.; title2 'Comparison Across 4 Seasons for Elk with all DAUs'; proc freq; The PROCEDURE FREQ used 1.05 minutes. where species='Elk ' & seasonA='4'; by species year sex; tables season*age I chisq cellchi2 nopercent nocol; format age elkfmt.; title2 'Comparison Across 3 Seasons for Elk with all DAUs'; run; The PROCEDURE FREQ used 1.05 minutes. SAS Institute Inc., SAS Circle, PO Box 8000, Cary, NC 27512-8000 �341 I .j I M E M 0 RAN DUM June 21, 1988 To: Distribution From: Gary C. White C~-<...-JI Re: Variance of Age and Sex Ratios Introduction Bowden et al. (1984) proposed th~t age and sex ratios for mule deer should be based on a sample taken from the population of groups of deer. The estimator they proposed is the same as that for a sample of the population of individuals. However, the variance of the estim~te is considerably different. Bowden et al. (1984:504) compare the estimators for 10 samples, and conclude that the standard error of the proportion of fawns to fawns plus does is about 70% too large for the estimator based on individuals, but that the standard error of the proportion of bucks to bucks plus does is about the same for both the group and individual estimators. The conclusions of Bowden et al. (1984) are based on strictly theoretical grounds, because the true variance of the estimates is unknown. The comparison of the 2 competing estimators does not include a comparison to a known variance. Although they conclude that the estimator based on groups should be used, they present no evidence that the smaller variance froOo this estimator is not too small, and that confidence intervals calculated with this variance estimate will perfo~m as stated. I have populations performance relative to simulated the 2 competing estimators with 6 empirical where the true variance can be determined empirically, and thus of the 2 competing variance estimators can be determined the empirical variance of the point estimator. Note that this analysis does not examine the question of whethe~ aerial surveys performed by CDOW biologist provide an unbiased estimate of the proportion of the age and sex classes. That is, if the population is not sampled in a representative fashion, estimates will be biased. What this analysis examines is, given the observed sample from a sex and age ratio survey, which of 2 competing estimators of the variance of the point estimates should be used to compute confidence intervals. Methods Age and sex ratios are difficult to work with because a ratio may be distributed from 0 to a limit of infinity, i.e., if no adult females are observed, then, the number of young divided by the number of. females is �•L , 342 Variance of Age and Sex Ratios -- June 22, 1988 undefined. quant ity Thus, as doe~ Bowden et al. (1984), I will consider the Ey = 'jj (Y + f), where Ey is the proportion of young to young plus females, I is the number of adult females, and Y is the number of young in the sample. Likewise for adult males, EM=M/U1+f), where Ey is the proportion of males to males plus females, and M is the number of males in the sample. As noted by Bowden et al. (1984), the ratio of young to females (Ry) is just Ey/(1 - Ey), so the ratio can be easily constructed from the proportion, as well as a confidence interval. To assess each of the variance estimators, a sample of groups of animals was taken as an empirical population. That is, the true population is taken as an observed sample of actual animals. Then, this population is sampled repeatedly to form estimates of Ey and EM. The mean of the estimates of Ey and EM provides an estimate of the expected values of Ey and EM' Further, the standard deviation calculated for the estimates of Ey and EM provides an empirical estimate of the true standard error for a single estimate. Four samples of deer and 2 of elk were used to compare the 2 estimators (groups and individuals) of the standard errors of Ey and EM' The 6 samples are described in Table 1. Table. 1. Description of the 6 data sets used as a known population from which samples were taken to estimate Ey and EM. Mean Group Size Group Size Range Sma 11 Large Species Area Sampled Year Number Groups Deer Piceance Basin 1976 567 3.3 1 20.:' :0.376 0.163 Deer Piceance Basin 1977 815 4.2 1 25 0.406 0.149 Deer Gt·1Us52, 62, 1986 63, 64, and 70. 816 9.1 1 65 0.322 0.131 Deer GNUs 52, 62, 1987 63, 64, and 70. 958 8.6 1 66 0.355 0.164 Elk GNUs 54, 64, 1986 66, 70, and 521. 135 35.4 1 428 0.307 0.097 Elk GNUs 54, 64, 1987 66, 70, and 521. 448 20.5 1 410 0.317 0.146 Ey �343 Variance of Age and Sex Ratios -- June 22, 1988 For the Piceance Basin samples, males were classified as either immature or mature males, so that EM could be further subdivided. For each population, 10Q_0 replicate estimates of Ey and EM ~ere made. For each replicate, 100 groups were drawn from the population at :~nd_g!", with replacement. Results The estimates of Ey and EM were not biased (E > 0.50) for any of the deer populations, but were biased high (E < 0.00l) for both Ey and EM for both elk populations. This can be seen by comparing the true values of £y and EM given in Table 1 with the average of the 1000 estimates of Ey and EM given in Table 2. The relative bias of £y is calculated as 100(~y - £y}/£y and likewise for EM. The relative bias of £y and EM is less than 1% for all 4 deer populations. However, the relative bias of Ey is 7% and 5% for the 2 elk populations, and for EM, relative bias is 19% and 12% for the 2 elk populations. Thus, a significant bias of the point estimator occurs for the large group sizes encountered in elk populations. Table 2. Results of 1000 simulations for each of 6 populations, where 2 estimators of the standard errors of ~y and ~ are compared. AVE is the average of the 1000 replications, SO is the standard deviation for the 1000 replications. Species Year A~E _y A~E -M SD(Ey) Individuals AV~ AV~ SD(_t~) SE(_y) SE(m} GrouQs AV~ AV~ SE(_y) SE(.rH) Deer 1976 0.375 0.162 0.0231 0.0280 0.0_?82 0.0248 0.0232 0.0273 Deer 1977 0.406 0.149 0.0199 0.0243 0.0253 0.0218 0.0198 0.0238 Deer 1986 0.322 0.131 0.0147 0.0166 0.0163 0.0133 0.0144 0.0171 Deer 1987 0.355 0.163 0.0150 0.0194 0.0172 0.0151 0.0147 0.0194 E1k .. 1986 0.329 0.115 0.0212 0.0165 0.0088 0.0069 0.0206 0.0160 E1k 1987 0.332 0.163 0.0238 0.0219 0.0116 0.0101 0.0210 0.0208 The variance estimator based on groups performed much better than the estimator based on individuals! partic~lar..1.Y(f9~elk (Table 2). T~e. performance of each of the est1mators 1S made by comparing the emp1r1cal estimate of the standard deviation (i.e., SD(Py» with the average of the 1000 estimated standard errors (i.e., AVE SE(~y» for each of the two estimators (individuals and groups). The square root of the-variance �.. 344 Vari ance of Age and Sex Ratios estimate gives standard error estimate of the estimate. This sizes cause the sma11, whereas to the empirical error based on values for elk deviation. - - June 22, E: ; the standard error for each tr : '.1_ , cr: for groups is generally much (' ",:,;;." ",) standard deviation, and thus .·:":'~\'·.~f., ; is particularly true for the 0.t u:tG. vari ance estimate based on i r ~ \') ,:IU , : ::; I: ' the average standard error fo: l,'n! p..; ~ ,; ., standard deviation. However even ~.~ groups appears biased low, as: 4 averl~~ are less than their corr-espon. ':I':J c,K;j{ !._c.i "i_, r (.0 The final conclusions about the use ful nr. ;)'1 fcC;', (:I ,. \, estimators comes down to how good the conf idt c,' ';n;~u·· i.:~·~ ..•: •. each of them. Results are presented in Table ~, -rot (t" [; 1';,:,;1' where a 95% confidence interval is computed t-l';·~·~~.~} ·;.i~...l"' ...··.~L.~. -t';' groups variance estimators. .' ;,\ . Tabl e 3. Resul ts for confidence i nterva 1 cov ,-i'~:' "t :,::YJ each of 6 populations. A 95% confidence tntev-: ... L,;:,.,;. estimate. The interval either is entirely a ',:\;,! (1;;;.<' ~Ti; t:.:: entirely below (Be.) the true value, or else (,),(""<; C·",.' value. ,< .: .. Individuals ~~ v- '.1 '. ,_;'.': Species ______ Year Deer 1976 0.7 1. 2 98.1 2.7 6.3 91.0 Deer 1977 0.8 0.7 98.5 3.1 5.8 91.1 Deer 1986 1.1 1. 9 97.0 5.1 7.3 87.6 Deer 1987 1.3 0.9 97.8 4.7 8.S 86.8 E1 k 1986 59.0 3.8 37.2 58.7 1.7 39.6 f" E1 k 1987 34.8 3.8 61.4 43.5 3.8 :~. I ,I -.Y·,(_ --:--_'_~Y-- --~PM~-- . :...:.Ab=-.=--..=:B.:::..e..:.,.. _,C::..::o:....:,v_,_. _-,-A.:..::b~. ____;B=e::....:.:.......,,:.C.:::..ov.!-:-. _,.. r '.,._ ..J~.;.~ ... : ;:,\i . --------------------_ " ....'. \ ...• J. .:., " I ';, ,-' ~. " • ~. t. ' .. ,.' . " ~ } } i ., ..\ 52.7 ...•...... . .'} . < , . .: " ,~ .z -.... ----. _ •. _ •....•...•... _. If the estimator of the parameter is unb i.» :~d (::;1";01.:)/ n + "i:~.. 1 case for e 1k}, and if the est i mated standard eq . ( .::; COd'", '> .o- ;, true for the estimator based on groups), then ';;,:: ;'0(. fi d: »c. " should cover the true parameter value 95% of U ' L;;:f~•. i,;~ -.~" ~'," '!, the confidence interval for the standard error ;_.;~;e(; if'! ~. l' .. p: G I~,; relatively well for deer, i.e., the lowest COVL;:~:W \t,'·~('·.1: \~,:",. ;~' ';~~ 1976 deer data, where 92.9% of the computed cor;'; ..';~~p 11','.": <'r j' 'j~r" the true parameter value. I consider this lew, "{::",C", >.? ..:; :~ f ',I' . good. In contrast, for deer, the coverage for ':".~~: ~.:·~~:·:·f"_-':I;,.:)~ ~)(.~(;:~ ··.'r· :~r ~~~!)i1~~1!y~e~~~ ~~ ~~ot~~r~~ehf~~'~: t~~rc~~;,J';:i.::: ~,'~,~~~~'".'~:~;, ;~;.:..;:(:Ugfj �345 Variance I o( Age ~nd Sex R~tios -- June 22, 1988 individuals is verypoor , giving only 61.4% coverage at best for ~y. Th'i estimator t>~sedon groups~does much better, with the worst coverage for £y el k.;in- }986~' Much of thi s - 1ack of coverage is due to the bias of the poi nt est tmator , because most of the confidence intervals missed the true paramete~, by being above' tt , - .: The fnl l ow'ing is a' summary graph demonstrating the effects of an increase inmean qroup .s ize on both bias and precision. The increase in bi as is shown, for the 1ar-.ger group sizes found for elk. Further, the breakdown of the estimator of the standard error based on individuals is also clearly demonstrated for the 2 elk data points. '. " Relative Bias Males . .' , , Mean .' Group Size - '\ SD Young SD Males Ind. SE Young Ind. SE Males Grp. SE Young Grp. SE Males o~~~--~------~--~~~~--3.3 4.2 8.6 9.1 20.5 35.4 "1 ' t. Mean Group Size �346 Variance of Age and Sex Ratios -- June 22, 1988 Discussion One problem with the analysis presented here is that populations with larger mean group sizes also had the smaller numbers of observations. The correlation between mean group size and number of groups in the population is 0.83, so that the 2 effects are confounded. Additional simulations should be done where the larger populations (all deer) are subsampled to be sure that the observed changes in bias and precision as a function of group size are due to group size, and not due to a problem of sampling a small population. Conclusions Results of this analysis suggest that for deer, use of standard errors based on the binomial estimator to ~ompute confidence intervals would not be particularly unsatisfactory. However, this estimator is totally unacceptable for elk data. Old data sets existing in the files for deer can still be used to compute an approximate confidence interval, but such an approach is not useful for elk. Future work should incorporate the additional information available from recording group sizes. Recommendations Based on this analysis, I suggest that biologists collecting age and sex data should record the data by groups for both deer and elk, so that confidence intervals based on groups can be computed. I will modify the population database that I have been developing to incorporate this information, and the software will provide confidence intervals on age and sex ratios based on the standard error computed from groups when this information is available. The advantages gained for deer are not as great as far elk. but I believe that a standardized procedure for both species offsets the effort required for deer. Literature Cited Bowden, D. C., A. E. Anderson, and D. E. Medin. 1984. Sampling plans for mule deer sex and age ratios. J. Wildl. Manage. 48:500-509. Distribution: ~ Carpenter Bruce Gill Jim Lipscomb Dave Freddy Dick Bartmann Dave Bowden " ; . � https://cpw.cvlcollections.org/files/original/e331294ea03e68cc875af71cb23b5b01.pdf 03c56be0cffbd6d754dfcf202b5dff3e PDF Text Text 1 Colorado Division of Wildlife Wildlife Research Report December 1988 JOB PROGRESS REPORT State of __~C~o~l~o~r~a~d~o~ Project 01-03-212 (W-88-R) Work Plan Job Title: _1_ Avian Research - Migratory Birds 14 Ecological studies of the flightless period of ducks in Colorado Period Covered: Author: : Job _ 01 January 1987 through 31 March 1988 James K. Ringelman Personnel: M. Szymczak, Colorado Division of Wildlife ABSTRACT No field work or extensive data analyses were conducted during this reporting period. Plans for next segment include comprehensive data analyses, completion of a final report and preparation of manuscripts. ��3 Colorado Division of Wildlife Wildlife Research Report December 1988 JOB PROGRESS REPORT State of __~C~o~l~o~r~a~d~o~ Project 01-03-212 (W-88-R) Work Plan Job Title: 1 Avian Research - Migratory Birds 15 Development and use of a physiological condition index for monitoring wintering mallard nutrient reserves Period Covered: Author: : Job _ 01 January 1987 through 31 March 1988 James K. Ringelman Personnel: M. Szymczak, Colorado Division of Wildlife ABSTRACT No field work or extensive data analyses were conducted during this reporting period. Plans for next segment include comprehensive data analyses, completion of a final report and preparation of manuscripts. ��Colorado Division of Wildlife Wildlife Research Report December 1988 JOB PROGRESS REPORT State of __~C~o~l~o~r~a~d~o~ Project 01-03-212 (W-88-R) Work Plan 1 Job Title: Avian Research - Migratory Birds 16 Field feeding ecology of mallard ducks Period Covered: Author: : Job _ 01 January 1987 through 31 March 1988 James K. Ringelman Personnel: M. Szymczak; Colorado Division of Wildlife; D. Chapman, W. Dean, Colorado State University. ABSTRACT Feeding trials using pen-reared mallards (Anas platychynchos) were conducted in standing corn stubble containing whole ears only from 30 January to 18 February 1987. Mallard feeding rates on corn kernals varied by corn density, which ranged from 50 to 742 kg/ha. Feeding rates also differed among individual birds across all corn densities. Corn consumption rates on whole ears were similar to feeding rates on kernals at low (100-200 kg/ha) densities, but appreciably lower than feeding rates on kernals at higher densities. Local enhancement, wherein social interactions c~use .birds to observe and join successful foragers, minimized variatiorl among individuals and across densities. ��7 FIELD FEEDING ECOLOGY OF MALLARD DUCKS James K. Ringelman Man has drastically altered waterfowl habitat during the last 100 years. Widespread drainage of inland wetlands and alteration of coastal areas has had detrimental effects on waterfowl, but water development projects and irrigated agriculture have created new wintering and migration habitat. In Colorado, relatively few waterfowl were present in winter until irrigated cereal grain crops were introduced in the mid-1800's (Steinel 1926:174). Within a decade, waterfowl were being "short-stopped" along their traditional migratory routes, attracted by newly-created reservoirs and abundant waste cereal grain (Buller 1975). Wintering waterfowl, particularly the mallard, became so plentiful in the 1940's that a special season was held on mallards in Colorado during 1942-43 to help alleviate damage to grain crops (Wagar 1946). Mallards remain the most common wintering duck species today and accounted for 65% of the total duck harvest in 1981 (Colo. Div. Wildl. 1981). Wintering mallards, like all inland wintering waterfowl populations, are highly dependent upon waste products of agriculture for food (Girard 1941, Reed 1971, Sugden et al. 1974). In Colorado and adjacent states to the east and south, waste corn comprises from 50 to 90% of the winter diet (Gordon 1981, Jorde 1981, Baldeassaree and Bolen 1984). Despite the importance of corn to waterfowl, little is known of the factors tha~ regulate its use by ducks. Harvester efficiency, slope of the land, and corn moisture content all affect the amount of corn remaining in the field after harvest (Baldassarre et al. 1983). This "wastage", typically 3-5% of the pre-harvest corn crop, contributes the bulk of cereal grains necessary to sustain waterfowl throughout the winter. The amount of this wastage used by ducks varies depending on post-harvest treatments including discing, plowing, burning, and cattle grazing (Jorde 1981, Baldassarre and Bolen 1984), Economic forecasters predict radical changes in eastern Colorado irrigated agriculture within the next 7-17 years. Four factors will play important roles in this transformation: (1) depletion of ground water aquifers, (2) rising energy costs and related impacts on the cost of operating pumps, (3) conversion of farmland to urban use, especially along the Front Range, and (4) corn prices. Nearly 13% of all Colorado cropland is planted to irrigated corn and it ranks second behind wheat in crop value (Colo. Dep. Agric. 1982), However, under scenarios of rising energy costs and groundwater depletion, corn is the first irrigated crop to become economically unfeasible (Sharp 1979). The break-even point is when electricity to power pumps reaches $0.12fkwh (Oamek 1981:64), and some scenarios predict the disappearance of irrigated corn from the region overlying the Ogallala Aquifer by 1990 (Young et al. 1982:129). Front Range area croplands, which benefit from gravity flow irrigation water transported by canals, are under increasing pressure from urban growth. In the last 2 decades, Colorado:has seen over 1.3 million acres converted from agricultural use (Colo. Dep. Agric. 1980). Much of this development occurs on irrigated land (U.S. Dep. Agric. 1978). The key to preserving wintering waterfowl and subsequent harvest opportunity is the management of water areas coupled with more intensive land management practices, particularly in relation to cornfields on Division of Wildlife and private lands. Based on historical evidence and knowledge of wintering waterfowl food habits, it is believed that loss of cornfields will �resul t in maj or shifts of birds out of an area. In the 'case of the Front Range, this would result in severe loss of hunting opportunity where demand is greatest. This would also be true elsewhere in eastern Colorado where hunting pressure and demand is somewhat less pronounced, but nevertheless important. Little is known of how mallards use cornfields and waste grain, so it is not possible to determine the area of cornfields needed to sustain a given mallard population. In the past, such information was unneeded because of abundant corn crops. However, with the expected declines in irrigated agriculture in the near future, these data will be necessary to maintain wintering waterfowl. Past field-feeding studies have focused on the timing of flights and the relationships between flight times and weather (Hochbaum 1955, Swinebroad 1956, Bossenmaier and Marshall 1958, Winner 1959, Gordon 1981, Jorde 1981), or on ways to alleviate crop damage by ducks (Gollop 1950, Hammond 1952, MacLennan 1973). Only recently have studies documented the potential value of post-harvest treatments in making fields more attractive to ducks. Jorde (1981:50) described a commensal relationship between field-feeding mallards and cattle which exposed corn in times of heavy snowfall. Baldassarre et al. (1983) reported that treatments such as burning of discing of fields with moderate amounts of waste corn made these fields more attractive to ducks than untreated cornfields of standing stubble with waste corn densities many times greater. This suggests an "optimal foraging" strategy of field-feeding ducks in which feeding rate is balanced with other considerations such as search time, handling time, and distance to field. A large body of information on optimal foraging in birds exists in the ecological literature, but thus far these findings have not been applied to the management of field-feeding ducks. Efforts must be made to evaluate methods of making waste corn more available to waterfowl, thereby optimizing feeding rates and winter physiological condition. P. N. OBJECTIVES 1. Identify the relationships between feeding rates of mallards and waste corn density, group foraging size, sex, and age of duck. 2. Relate post-harvest cornfield treatments to foraging efficiency. 3. Document the foraging habitat requirements of wintering mallards. 4. Develop a model for post-harvest management of cornfields for wintering mallards. SEGMENT OBJECTIVES 1. Contact local farmers to arrange a cornfield lease. ears from 1 ha of corn during late summer. Hand pick and remove 2. In fall 1986, "harvest" the cornfield plot using standard techniques leaving canes, leaf litter, and stubble in place. 3. During January-March 1987, quantify the feeding rates of mallards as a function of kernal density on whole ears in standing stubble. �9 4. Summarize and compare feeding rates of mallards by cornfield treatment and corn density. 5. Derive functional response curves of feeding rates by treatment and corn density. 6. Monitor use of cornfields by mallards radio-marked in conjunction with Work Plan 1, Job 17. Evaluate duck use in relation to post-harvest treatment, hunting disturbance, snowfall, and proximity to roost and refuge areas. 7. Compile and analyze data and prepare progress report. METHODS A cornfield located just east of Wellington, Colorado was selected for use in field-feeding experiments. Whole ears were hand-picked from a 8 x 500 m area during early September 1986. Corn was harvested in mid-September, and permanent plot markers were established shortly thereafter. An electric fence was erected to exclude cattle from the plots. Panels measuring 1.2 x 2.0 m were used to enclose square plots 7.3 m on a side. Whole ears of corn were randomly dispersed in the enclosure. Mallards, which were previously conditioned to eat corn from ears in mock feeding trial situations, were deprived of food 24 hours before a trial. Eight birds of each sex were weighed to the nearest gram on an electronic digital balance immediately before each trial. Mallards were released gn ~ into the enclosure, allowed to feed for precisely 5 minutes, then rounded up and reweighed. The amount of corn ingested was assumed to equal the difference between starting and ending body mass. A BASIC computer program was written to estimate the weight of kernals on a whole ear of corn based on weight and linear measurements of the ear. This mathematical relationship was derived using stepwise, forward linear regression models that related the measured weight of kerna1s on an ear to linear combinations of ear length and weight prior to removing kernals. The following equation was used to estimate total kernal weight: K - E - (0.03643 where: K X * kernal weight (g), E ear length (cm) R (X * 3.1416 * R2) - 28.722) weight of the whole ear (with kernals) (g) (ear diameter at center (cm) + 5) / 2 The Pearson Correlation coefficient between estimated and true kernal weight was 0.94 on the sample of 10 ears used to establish this relationship. Several ears were used to achieve kernal densities of 50 to 742 kg/ha, which corresponds to the range of density values used in prior experiments with kernals. Since mallards depleted a significant proportion of available corn, particularly at lower initial densities, an "ending density" was calculated by subtracting the total corn consumption for the trial from the initial dosage. An "average density" was then computed as the mean of the initial and ending densities. Average density was used to test for �10 differences in feeding rates by density and treatment. Birds with feeding rates above the median were used to quantify maximum feeding rates. RESULTS Twelve feeding trials were conducted using whole ears in standing stubble. A wide variation in feeding rate within density, reflecting differential foraging success among individual birds, was apparent in every trial. In considering birds only above the median, variation was greatest at kernal densities less tha 400 kg/ha. In contrast, variation in feeding rates with kernals in standing stubble was highest at densities between 200 to SOO kg/ha. When averaged across all densities, feeding rates differed among birds (~ 0.05; Table 1). The feeding rate of the highest bird (9) was 79% greater than that of the lowest bird (5). Trends in individual feeding rates by sex were not apparent. Table 1. Feeding rate of individual mallards on whole ears of corn dispersed in standing stubble, averaged across all corn densities and trials. Bird 9 7 10 14 13 1 12 11 16 S 6 4 17 3 2 5 # Mean feeding rate (g/min) 5.95 5.63 5.54 5.53 5.50 5.1S 5.12 4.S3 4.65 4.51 4.40 4.24 4.23 4.14 3.S6 3.32 a a,b a,b a,b a,b a,b,c a,b,c a,b,c a,b,c a,b,c a,b,c a,b,c a,b,c a,b,c b,c c Sex M F M M M F M M M F F F M F F F a Means with the same letter do not differ (P>0.05). Feeding rates increased rapidly between densities of 0-200 kg/ha, but this rate of increase declined sharply above 300 kg/ha (Fig. 1). Asymptotic mean feeding rate was approximately 6.5 g kerna1s/minute on whole ears, although unexpectedly high feeding rates were achieved at densities ranging from 50-339 kg/ha (Table 2). �.il. -:E z <, 12 10 o w ~ « a: "za « a: 8 ....~~-------------------------- 0 D ~~~~ --------0-----------0---------- 6 0 4 0 LL 2 0 300 100 500 700 900 1100 MEAN CORN DENSITY (KG / HA) Fig. 1. Foraging rates of mallards on whole ears of corn. -z 12 o :E ........10 w ~ « a: o z a« a: ____ --------0 o e o 8 o o ------0------------------------------------------------6 4 o LL 2 o 100 300 500 700 900 MEAN CORN DENSITY (KG / HA) Fig. 2. Foraging rates of mallards on corn kernals. 1100 �12 Table 2. kerna1s. Foraging rates of mallards on whole ears of corn by density of Density (kg/ha) Significance8 Mean foraging rate (g/min) 50 62 67 83 109 147 158 335 339 367 535 742 6.92 4.66 4.23 4.29 4.07 6.54 5.20 7.34 6.64 4.41 6.80 6.61 a b b b b a· b a a b a a 8Means with the same letter do not differ (P>0.05). DISCUSSION Unlike loose kernals, wherein feeding rates continue to increase at densities above 300 kg/ha (Fig. 2), mallards did not increase their maximum feeding rates above this density (Fig. 1, Tables 2,3). These two feeding response curves quickly diverge at densities above 300 kg/ha, reaching asympotic feeding rates of 9.3 and 6.5 kg/ha with kernals and ears, respectively. Table 3. Estimated foraging rates of mallards by density of corn kernals and treatment (from previous experiments). Foraging rate (g/min) by treatment Density (kg/ha) 100 200 300 400 600 800 1000 1200 Bare ground 10.3 11.8 12.7 13.3 13.8 13.9 13.9 14.0 Kernals Disced stubble8 4.7 6.3 7.2 7.8 8.6 9.0 9.3 9.4 8 Corn kernals applied to sample plots prior to treatment. 0.1 0.1 0.3 0.7 1.7 2.0 5.0 �Optimal foraging theory (Pyke et al. 1977) can be helpful in understanding the behavior of feeding birds and makinz management decisions about post-harvest treatments. Handling time, which is an important factor in the selection of barley and wheat strains (Clark et al. 1986), was insignificant for corn kernals on dirt substrate and minimal for kernals in standing stubble, where search time was the primary time factor. With whole ears however, birds frequently struggled to remove kernals. Maximum feeding rates were apparently limited by both search and handling time of ears, thus accounting for differences observed among treatments. Feeding rate on whole ears was 30% lower at 800 kg/ha than the feeding rate on loose kernals at the same density, suggesting that about one-third again as much time is needed to forage on whole ears owing to increased handling time. In the range of normal waste corn densities (200 to 400 kg/ha, Baldessarre and Bolen 1984), this handling time resulted in a large decrease in feeding efficiency. Since mallards consume from 34 to 64 g of corn/feeding bout (Whyte and Bolen 1985) and kernals on ears comprise 70% of the total corn available (Baldassarre et al. 1983), minimum feeding time in a typical cornfield should be about 5-10 minutes. Assuming 2 field-feeding flights/day, total daily feeding time could be less than 20 minutes (not including flight time). Other factors such as flock size, which affect opportunities for social interactions and local enhancement for food-finding, may also interact with forging rates. Thus, under normal conditions, mallards on high plains wintering areas can afford to adopt a strategy of time minimization (Pyke et al. 1977), thereby conserving energy and affording time for courtship as well as other, less demanding behaviors. LITERATURE CITED Baldassarre, G. A., and E. G. Bolen. 1984. Field-feeding ecology of waterfowl wintering on the southern high plains of Texas. J. Wildl. Manage. 48:63-71. ____________________ , R. J. Whyte, E. E. Quinlan, and E. G. Bolen. 1983. Dynamics and quality of waste corn available to postbreeding waterfowl in Texas. Wildl. Soc. Bull. 11:25-31. Bossenmaier, E. F., and W. H. Marshall. 1958. Field-feeding by waterfowl in southwestern Manitoba. Wildl. Monogr. 1. 32 pp. Buller, R. J. 1975. Redistribution of waterfowl: influence of water, protection, and feed. Proc. Int. Waterfowl Symp. 1:143-154. Clark, R. G., H. Greenwood, and L. G. Sugden .. 1986. Influence of grain characteristics on optimal diet of field-feeding mallards. J. Appl. Ecol. 23:763-771. Colorado Department of Agriculture. 1980. Agricultural land conversion in Colorado. Resour. Analysis Sect., Colorado Dep. Agric., Denver. 8 pp. �i4 1982. Colorado agricultural statistics. Livestock Rep. Serv., Denver. Bull. 1·82. 94 pp. Colo. Crop and Colorado Division of Wildlife. 1981. Colorado small game, furbearer and varmint harvest, 1981. Colorado Div. Wi1d1., Denver. 228 pp. Girard, G. L. 1941. The mallard: Wildl. Manage. 5:233·259. its management in western Montana. J. Gollop, B. J. 1950. Report on investigation of damage to cereal crops by ducks in the prairie provinces. Unpubl. Rep., Can. Wildl. Serv., Ottawa. 11 pp. Gordon, D. H. 1981. Condition, feeding ecology, and behavior of mallards wintering in northcentral Oklahoma. M.S. Thesis, Oklahoma State Univ., Stillwater. 68 pp. Hammond, M. C. 1952. Waterfowl damage and control measures, Lower Souris Refuge and vicinity. Unpubl. Rep., U.S. Dep. Inter., Fish and Wildl. Serv., Washington, D.C. 5 pp. Hochbaum, H. A. 1955. Press, Minneapolis. Travels and traditions of waterfowl. 301 pp. Univ. Minnesota Jorde, D. G. 1981. Winter and spring staging ecology of mallards in southcentral Nebraska. M.S. Thesis, Univ. North Dakota, Grand Forks. 116 pp. MacLennan, R. 1973. A study of waterfowl crop depredation in Saskatchewan. Can. Wildl. Serv., Saskatoon, Saskatchewan. Wildl. Rep. 2. 38 pp. Oamek, G. E. 1981. Economic adjustments to rising energy costs: the case for pump irrigators. M.S. Thesis, Colorado State Univ., Fort Collins. 90 pp. Owen, R. B., Jr., and K. J. Reinecke. 1979. Bioenergetics of breeding dabbling ducks. Pages 71-93 in T. A. Bookhout, ed. Waterfowl and wetlands--an integrated review. La Cross Printing Co., La Crosse, WI. Pyke, G. H., H. R. Pulliam, and E. L. Charnov. 1977. Optimal foraging theory:a selective review of theory and tests. Quart. Rev. BioI. 52:137-154. Reed, L. W. 1971. Use of western Lake Erie by migratory and wintering waterfowl. M.S. Thesis, Michigan State Univ., East Lansing. 71 pp. Sharp, R. L. 1979. Economic adjustments to increasing energy costs for pump irrigation in northeastern Colorado. M.S. Thesis, Colorado State Univ., Fort Collins. 72 pp. Steinel, A. T. 1926. History of agriculture in Colorado. ColI., Fort Collins, Colo. 659 pp. State Agric. �Sugden, L. G., W. J. Thurlow, R. D. Harris, and K. Vermeer. 1974. Investigations of mallards overwintering at Calgary, Alberta. Can. Field-Nat. 88:303-311. Swinebroad, J. 1956. Some aspects of the role of weather in bird migration. Ph.D. Diss., Ohio State Univ., Columbus. 315 pp. u.S. Department of Agriculture. 1978. Urbanization of rural lands in the northern Colorado Front Range. U.S. Dep. Agric., Washington, D.C. 23 pp. Wagar, J. V. K. 1946. Colorado's duck-damage, grain-crop problem. North Am. Wi1d1. Conf. 11:156-162. Proc. Whyte, R. J., and E. G. Bolen. 1985. Corn consumption by wintering mallards during morning field-flights. Prairie Nat. 17:71-78. Winner, R. W. 1959. Field-feeding periodicity of black and mallard ducks. Wildl. Manage. 23:197-202. J Young, R. A., L. R. Conklin, R. A. Longenbaugh, and R. L. Gardner. 1982. Energy and water scarcity and the irrigated agricultural economy of the Colorado high plains: direct ecnomic and hydrologic impact forecasts (1979-2020). Colorado Water Resour. Res. Inst., Colorado State Univ., Fort Collins. 362 pp. Prepared bY~Z_~~ es K. Ringe m n Wildlife Researcher C ��17 Colorado Division of Yildlife Wildlife Research Report December 1988 JOB PROGRESS REPORT State of __~C~o~l~o~r~a~d~o~ Project York Plan 01-03-212 (Y-88-R) 1 Job _ Avian Research - Migratory Birds 17 Job Title: Habitat use by wintering mallards along the Front Range of Colorado Period Covered: 01 January 1987 through 31 March 1988 Authors: James K. Ringelman and Michael R. Szymczak Personnel: K. Ragotzkie, Colorado Division of Yildlife; J. Barnett, L. Benson, R. Yestfall, Colorado State University. ABSTRACT Twenty-five mallards were captured and radio-marked at Chestnut Slough, 10 km south of Greeley, Colorado, during early December 1986 and 1987. Movements and habitat use of marked and unmarked mallards were measured from December through February to determine relationships among hunting activity, weather and habitat selection. Focal animal time budget data of unmarked mallards were collected to aid in understanding habitat selection by instrumented ducks. Yinter temperatures and snowfall differed between years, thereby influencing habitat availability, usage, and duck behavior. Of the 367 wetlands (1,266 ha) on the study area, most were frozen and unavailable during winter. Home range sizes averaged 154 ha in 1986-87 and 120 ha in 1987-88. Yarm-water wetlands, lakes, and wetlands closed to hunting were key components in the home range' of mos t; birds •. Although they represented'<1% of the surface water on the study area, warm-water wetlands were used extensively by ducks and were highly selected during both winters. During .themild winter of 1986-87, portions of lakes and small ponds remained open and received greater use than in 1987-88 when these habitats were mostly frozen. Mallards used rivers, holding ponds and ditches extensively in 1987-88. Yhen cornfields became snow-covered for an extended period in 1987-88, ducks switched to feeding in and around cattle feedlots. Adult females used lakes more frequently than males, and adults made greater use of rivers than did immatures of either sex. Resting was the most. common behavior during both winters, followed by swimming and water feeding. Courtship displays were most common on reservoirs and warm-water wetlands, peaking during December and January. February behaviors included more resting but less water feeding than in January. Behaviors suggest that lakes and warm-water sloughs serve as courtship arenas during the period of pair formation. ��HABITAT USE BY WINTERING MALLARDS ALONG THE FRONT·RANGE OF COLORADO James K. Ringelman Michael R. Szymczak This report documents the accomplishments of two and 1987-88. Parenthetical ~eferences to years refers or results from a single field season. The absence of implies objectives, methods or findings common to both field seasons, 1986-87 to objectives, methods such a reference field periods. P. N. OBJECTIVES 1. Relate mallard habitat use to the physical characteristics of wetlands, aquatic and upland plant coIllIllUD1tiesr we1t.land . macro invertebrate populations, vea~eT. and bunting regimes. 2. Characterize mallard use of wetlands through time budget techniques. 3. Document the composition of the wetl~~ community within the study area, and relate wetland use by mallards to availability. SEGMENT OiJ.ECTIVES 1. Capture and radio-mark 25 mallards during early December. marked sample equally by age anm SEX. Divide the 2. Monitor the diurnal movements of ~t~ented mallards using aerial and vehicle-mounted tracking systems. <code bird locations using a Universal Tram;·'erse Mercator (UTM) grid sySte1n_ 3. Conduct aerial tracking flights once a week, or more frequently if weather conditions or bird movemen~ warran~~ 4. Classify all study wetlands ~y geneTal we~and type, then digitize information for ease of retrie7al by computer systems (1986-87). Obtain aerial photographs of study we~lamilisto aid in delineating physical characteristics of each. 5. Determine the availability of ice-free wetlands daily using a representative sample of wetland types (1987-88). 6. Monitor hunting regimes on key wetlands to determine the effect of hunting disturbance on movemen~s of Ta~io-marked mallards. 7. Obtain National Weather Service records for daily temperature, wind and snowfall for a representative site in the study area. 8. Measure the microhabitat temperatures at warm-water wetlands for comparison with ambient conditions. 9. Quantify behavior of marked and unmarked mallards in relation to wetland type, social status, and time of day using focal animal sampling. , �20 STIJPY AREA The 1,089 km2 study area is located along Colorado's Front Range near Greeley, Colorado. The area is rectangular in shape (36.2 km east to west, 30.5 km north to south) and is bordered on the west by Interstate Highway 25, on the north by State Highway 392, on the south by State Highway 66, and on the east along the UTM line 542000• Upland habitats are typical of the Colorado Piedmont (Fenneman 1931) portion of the Great Plains physiographic province. Elevations average about 1430 m, with generally flat to rolling terrain interrupted by occasional steep bluffs along major river systems. The study area is drained by 4 rivers: the Cache la Poudre, Big Thompson, St. Vrain, and South Platte. Climate is characteristically continental (Gittings 1941), with December, January, and February daily temperatures averaging -1.3, -3.9 and -0.4 C, respectively. Average precipitation during these same months totals 0.74, 0.76 and 0.71 cm. Fog is common during warm winter mornings and evenings. Native grasses consist of blue grama (Bouteloua gracilis) and buffalo grass (Buchloe dactyloides), with rubber rabbitbrush (Chrysothamnus nauseosus) and snakeweed (Gutierrezia sarothrae) the dominant shrubs. Cottonwood (Populus sargentii) , willows (Salix spp.), and green ash (Fraxinus pennsylvanica) are common along watercourses. Aquatic vegetation varies by wetland type and water regimes. Large wetlands used for irrigation water storage are mostly devoid of vegetation due to extreme water level fluctuations during the growing season. Small wetlands often contain submergent watermilfoil (Myriophyllum exalbescens), pondweeds (Potomogeton spp.), coontail (Ceratophyllum dernersum)and muskgrasses (Chara spp.). Smartweeds (Pologonum spp.), sedges (Carex spp.), cocklebur (Xanthium strumarium), and cattails (Typha spp.) occur around wetland margins and in shallowly flooded areas. Watercress (Nasturtium officionale), a common aquatic of warm-water sloughs, harbors high densities of pond snails (Physa spp.) and other macroinvertebrates consumed by mallards. Most land in the study area is devoted to irrigated agriculture or livestock husbandry. Corn, alfalfa, wheat and sugar beets are the dominant irrigated crops. Malting barley and vegetables are grown in lesser amounts. Several large cattle feedlot operations exist in the northern portion of the area. Winter waterfowl populations typically range from several thousand to >10,000 mallards (Anas platyrhynchos), and up to 10,000 Canada geese (Branta canadensis). Pintails (Anas acuta), green-winged teal (Anas crecca) and wigeon (Anas americana) are present in lesser numbers. METHODS Mallards were captured at Chestnut Slough on 3 December 1986 and 2 December 1987 using Salt Plains bait traps (Szymczak and Corey 1976). In each year, 25 mallards were instrumented with back-mounted radio transmitters (Dwyer 1972) weighing 24 g. Measurements were made of wing length and body weight, and a standard U.S. Fish and Wildlife Service band affixed to each bird prior to release. Truck-mounted, precision direction finding antennae arrays were used to locate birds from the ground. When a signal was detected, 2 or more azimuths were taken from a known location then plotted on 1:24,000 topographic maps to a resolution of 1 ha. A transparent grid overlay was used to code the �21 location of each bird in the standard UTM grid system. Concurrent with information on the bird's location, the date, time, activity status, air temperature, precipitation, wind speed, wetland name, and habitat type were also recorded. In 1987-88, a portable computer (Tandy Model 102) was used to tabulate and error check data in the field. Standard field forms were used in 1986-87. All data were entered into an IBM-PC for subsequent analyses. In 1986-87, mallards were located as frequently as possible, usually 2-4 times/day. Tracking schedules in 1987-88 alternated between (1) locating as many individuals as frequently as possible during the day, and (2) constant monitoring of 1 or 2 individual birds during a single day. Aerial tracking was conducted only when several marked birds could not be located after extensive ground searches. Flights were made over the entire study area and, if necessary, along the Front Range from Wellington south to Barr Lake, and from Boulder east to Jumbo Reservoir. Responses of marked birds to hunting disturbance were obtained by constant monitoring at Chestnut Slough. Personnel arrived at Chestnut prior to arrival of hunting parties in the morning, and remained at the slough until either mid-afternoon or dark, depending upon scheduling of other activities. Activities on Chestnut Slough were ca~egorized by disturbance factors in the following manner: no disturbance (factor 0), shooting audible from Chestnut but not originating on the slough (factor 1), shooting on Chestnut >200 m from the subject bird (factor 2), driving near the subject bird (factor 3), walking near the subject bird (factor 4), and shooting <200 m from the subject bird (factor 5). Continuous monitoring of birds and hunters on Chestnut was conducted during the first 3 days of the hunting season and periodically thereafter. Wetlands were categorized into 5 habitat types. Small ponds and reservoirs were defined as wetlands <40 ha in surface water area. Lakes were wetlands >40 ha in size. Holding and sewage ponds were artificial wetlands created for treatment of wastewater. Gravel pits were wetlands created as a byproduct of surface mining for aggregates, generally along river courses. Warm-water wetlands included warm-water sloughs, which are maintained by subterranean seeps, ditches that carry a warm water during the winter (usually as a result of reservoir discharges), and ponds that remain open as a result of warm water provided by either sloughs or ditches. Ditches were man-made systems built to convey water for agriculture. Rivers included natural watercourses in the study area. The availability of wetlands varied by type and local weather conditions. Consequently, in 1987-88 a sample of wetlands typical of habitat types on the study area were monitored for ice conditions at least once a day. Percent open water for each wetland was estimated and recorded along with the date, time, and air temperature. Temperature data were also obtained at Chestnut Slough and Union Ditch. At the latter location, maximum and minimum temperatures were obtained 5 cm above the surface and 15 cm under water. Time budget data were obtained using focal animal sampling (Altmann 1974) stratified by habitat type, time period, gender, and social status (paired or unpaired) of the subject bird. Habitat types were reservoirs, rivers, warm-water wetlands, and other (mostly gravel pits). Time periods were sunrise-0900, 0900-1200, 1200-1500, and l500-sunset. Spotting scopes (40X) or binoculars were used for all time budget collections. Focal animals were selected by pointing the scope or binocular at the flock, then selecting the closest individual of the desired gender and social status. Behaviors were recorded continuously (Tacha et al. 1985) on either a hand-held tape recorder or directly on a portable computer (Tandy Model 102). The following �22 behavior classifications were used: (0) out-of-sight, (1,) rest, (2) swim, (3) walk, (4) preen, (5) feed in water, (6) feed on land, (7) courtship, (8) aggression, and (9) other. Time budget bouts were 15 minutes unless circumstances prohibited collection of data for the entire period. A Fortran computer program was written to select subsets of time budget data and summarize overall behaviors. Statistical analyses were performed on an IBM-PC using the Statistical Analysis System (SAS). RESULTS Weather and Ice Conditions Temperature and snowfall had a profound influence on wetland habitat and food availability, thereby mediating movements and habitat use of radio-marked birds. The 1986-87 field season was typified by above average temperatures and below average snowfall. Brief periods of cold occurred in mid December and January, but daily high temperatures were usually above freezing throughout the winter (Fig. 1). The 1987-88 winter was more typical of those along the Front Range, with daily low temperatures dipping below 0 F on several occasions during late December through January (Fig. 2). Daily high temperatures ranged from 13 to 30 F during this same period. Compared to temperatures regimes at Greeley, Chestnut Slough experienced colder low temperatures but warmer high temperatures (Fig. 3). Greeley temperatures are more typical of those experienced throughout the study area. Snow on the ground was less during 1986-87 than during 1987-88, reflecting differences in daily temperatures and snowfall between years. In 1986-87, snow cover was absent during late December into early January, and again from late January into early February (Fig. 4). In contrast, continual snow cover existed from 22 December 1987 until 18 February 1988 (Fig. 5). During this latter period, cornfields remained snow covered throughout most of the winter. Wetland Habitats Low level aerial photographs were used in conjunction with field observations and 1:24,000 topographic maps to characterize the surface area and number of wetland habitat types. Wetlands were digitized on computer, then displayed using commercially available software (Freelance) and hardware (HP Laserjet Series II, Fig. 6). Total wetland area was 1,266 ha for the 367 wetlands enumerated on the study area. Small ponds and reservoirs were the most numerous and comprised the largest number within a classification (Table 1). Ditches and canals were the second most numerous type, but occupied only 7.8% of the surface water area. Rivers and streams were next in abundance, followed by gravel pits, lakes, and holding/sewage ponds, respectively. Warmwater wetlands were few (n-IS), comprising <1% of the total surface water area (Table 1). The number and distribution of ice-free wetlands varied during 1987-88, reflecting daily temperature regimes and snowfall (Fig. 7). Except for occasional open water areas or "ice holes", small ponds and reservoirs became unavailable after 12 December. Ditches and rivers had dynamic ice conditions, responding more quickly to warming trends (Fig. 7). Riverine habitats averaged about 60% open water "during winter. Most ditches containing open water during winter carried warm-water sources. Warm water wetlands, by definition, never froze. �60 -- 50 LL W . ~. "7 -{ ~ - 40 a: :J t- < a: w Q. 30 20 ~ W t- \ • -,',- . "" ,-, .. , ____ O 't • ,.,,'~," :~ ,""-~iV ~' \: ~.' I' I, " '. ' .•' , 10 I I ," ,, I-~ I' \:. , ',".," I' I' , I. - :-:,~, ,,: ""' , ! :'! '- ", I , . ' .: ~ " ",I II ,,' ... , I, I , I,· •• • . ,- I' I I I, I,' ,, ,,, ,'" ,',. ,. '" , • I ' ~~L If " f ", . .' _ -10 1 10 20 30 Dec. Fig. 1. Dally maximum Colorado, 1986-87. 20 10 30 10 Feb. DATE and minimum temperatures 20 at Greeley 60 -LL 50 W a: :J 40 < cr 30 tW Q. - - - _,.__. ." t- , .. I 10 ,, ,, " " 0 ,~, 1-' •, 'I.,.... ,, 20 ~ W • I' I " , .' :. , ~,i ' I' ,I,.', ' ~,- , ! "~' I 'If ~: .1., . .'" I'" .•. , r , ",' I" • I ,, ,, , ~:~ .: "~ : ''f: V, -----~--~~~-~~~--~~------~------" I, I ~' -10 , f • _ '" ',,' -I l' I' " I, I' I \ • I • ~, I 1 10 20 Dec. Fig. 2. Daily maximum Colorado, 1987-88. 30 10 20 30 20 Feb. DATE and minimum temperatures 10 at Greeley �24 60 -- 50 LL W CC 40 ::> 30 ed: CC W 20 f- a. ~ W ,. - ,,' 10 1'\' I f- -- "",. •• , " • , , .. .n , -20 11 20 Dec. 30 , , I • I '.'.. 10 . , . , I , tI • I, I . . ,, .', . .', ~J- ~"""P"---- ' ·· ' • ,' "~ 30 10 Feb. DATE Fig. 3. Ambient maximum and minimum air temperatures Chestnut Slough, 1987-88. , I I ••~ ,.., '. 20 .' I' , I " I, I', .&.,--~-'-~~ 'f ',' ~ .'~ I , , I -10 , It •• ' I' . ,.. . " " • I , , " " , I' 7,t......!---~--_+'r+ I r' I. 1,·1 0 I " ~ at 20 �- :i ~ 8 c Z :J o a: 6 ~ 4 CJ ~ o Z CIJ 2 o 1 10 20 30 10 20 30 10 DATE Dec. 20 28 Feb. Fig. 4. Snow on ground at Greeley, Colorado, 1986-87. -~ 8 c Z :J o a: 6 Z 4 CJ o ~ o z CIJ 2 o 1 10 20 Dec. 30 10 20 DATE Fig. 5. Snow on ground at Greeley, Colorado, 1987-88. 30 10 20 Feb. 28 �N 0\ Wlnd.or tJ o () Pond rr R ~,~~" o --- ~ - .._, ~ .C1 ~ ~ o· ~\ "-J ~ 0 Greeley o o /~-f' r::) -r IJ v D <$>0 \. ?'10~~ ••........ ~ "V ,,\.(.I.\\e~ 0'1 ~ ~ Q c:::? Latham Res. Milton Res. o Ch•• tnut Slough o o 10 km ~ o p~ 1// / / / / / / / / / / / / / /1 I) 1:0'0 U ~ c. o~ c. Plett.vlll. Fig. 6. Digitized wetland habitat map of the Greeley study area. �27 100 --, ,,' I'I ...•.. ,...•.• 1 I I I 80 ...•.. "'I ,, 60 I \ \ , I / / / / I I \ \ \ \I , 20 I I \ I ,- -- ---, , ,, ' \/ ,I II 40 ,.- \ \ / \ I I -"'\ \ l DITCHES / ,, / I I \ I \/ 0 100 80 c:c 60 r- <X 40 ~ 20 W Z W CL 0 r- Z W RIVERS 0 100 80 U c:c W 60 RESERVOIRS CL 40 .; .. .. 20 .......... "'. ....... 0 100 /\ ....... ·.::··· ••••••••••• 0 •••••••••••••••••••••••••••• 0 •••••••••••••••••••••••••• -- -, • 80 • • • 60 I • • • •• 40 • 20 ",'. I, I. . ',,- ••• ,' " PONDS ,,,,', ',' '", I :. ' t " ..." •.~• - .•- - - •.•. - - - - - •.- •.•. -: 0 10 20 30 10 , :~ I ·20 • !_ - - •.- - - - - - - - - - , ' ...- - •. : ~- - - - •.- 30 Dec. 20 Feb. DATE Fig. 7. Percent open water during 1987-88 10 for 4 wetland types. �28 Table 1. Surface area and number of wetlands by habitat type on the Greeley study area. Habitat type Area (ha) Small ponds/reservoirs , Area (ha) , 513 40.5 130 35.4 112 8.9 3 0.8 84 6.6 20 5.5 112 8.9 24 6.5 8 0.6 15 4.1 Ditches/canalsC 99 7.8 107 29.2 Rivers/streamsd 338 26.7 68 18.5 1,266 100.0 367 100.0 Holding/sewage ponds Gravel pits Warm-water wetlandsb Totals ·Wetlands >40 ha. bCalculated as 33 km total length x 2.5 m width. cCalculated as 494 km total length x 2 m width. dCalculated as 268 km total length x 12.6 m width. Characteristics of Instrumented Birds Twenty-five mallards were captured and radio-marked each year at Chestnut Slough. The 1986 sample was stratified by age and sex as follows: 5 adult males, 8 adult females,S immature males and 7 immature females (Table 2). In 1987, 7 adult males, 6 adult females, 6 immature males and 6 immature females were marked (Table 3). The percentage of marked males was increased in 1987 because of the higher mortality among males during 1986-87. Thirteen birds were monitored for the duration of the first field season (27 Feb.), but only 6 mallards were present at the conclusion of the 1987-88 field season (Tables 2 and 3). Increased severity of weather and higher hunting mortality contributed to the loss of instrumented birds during the latter year. Mallards instrumented in 1986 were lighter (X-l095 g) than those marked in 1987 (X-1133 g, Tables 2 and 3). Table 2. Characteristics of mallards radio-marked on 3 December 1986 at Chestnut Slough. Bird No. Age Sex Weight (g) Wing "(mm) Fate 816 Immature Female 1,033 288 Died 2/10 837 Adult Male 1,054 301 Last Contact 2/27 �29 Table 2 (cont.). Bird No. Age Sex 'Weight (g) 'Wing (mm) Fate 862 Adult Female 972 281 Last contact 2/27 887 Adult Female 999 289 Last contact 2/27 900 Immature Female 1,060 281 Last contact 2/13 916 Immature Female 1,202 289 Last contact 2/27 936 Adult Male 1,173 296 Bad Radio 946 Adult Female 1,076 281 Last contact 2/27 963 Immature Female 266 Died 12/17 979 Immature Female 985 277 Last contact 2/27 995 Immature Female 896 271 Last contact 2/27 1020 Adult Male 1,068 308 Last contact 2/27 1063 Adult Male 1,208 309 Died 12/20 1099 Adult Female 1,111 283 Died/last con. 1/30 1111 Adult Female 1,140 281 Last contact 2/27 1126 Adult Male 1,236 300 Last contact 2/10 1142 Immature Female 873 282 Last contact 12/3 1155 Immature Male 1,116 287 Last contact 1/5 1174 Immature Male 1,205 296 Last contact 2/25 1189 Adult Female 1,021 275 Last contact 2/27 1202 Adult Female 1,110 275 Last contact 2/27 1232 Immature Male 1,226 297 Last contact 2/6 1249 Adult Female 1,082 284 Last contact 12/27 1714 Immature Male 1,214 291- Last contact 2/27 1732 Immature Male 1,210 285 Died 12/15 �30 Table 3. Characteristics of mallards radio-marked on 2 December 1987 at Chestnut Slough. Bird No. Age Sex Weight (g) 030 Immature Male 1,228 286 Last contact 1/2 048 Immature Male 1,163 285 Died 1/23 070 Adult Male 1,139 302 Shot 1/2 090 Immature Female 1,034 272 Last contact 2/25 109 Adult Male 1,333 297 Died 1/17 128 Immature Female 969 264 Last contact 2/26 150 Immature Female 1,040 270 Died 2/4 170 Adult Female 1,133 283 Radio removed 12/20 184 Adult Female 1,043 284 Last contact 12/31 220 Adult Female 1,102 284 Radio fell off 1/15 240 Immature Female 1,162 281 Last contact 12/23 266 Adult Female 1,042 279 Radio removed 12/22 282 Adult Male 1,246 283 Died 1/3 300 Adult Male 1,188 295 Last contact 2/26 312 Immature Male 1,235 290 Died (powerline) 12/29 330 Immature Male 1,204 280 Last contact 12/30 350 Immature Male 1,142 287 Last contact 12/31 372 Adult Female 1,040 275 Last contact 2/26 392 Immature Female 899 267 Shot 1/1 420 Immature Female 980 279 Last contact 2/26 438 Adult Female 1,012 279 Last contact 1/17 464 Immature Male 1,140 291 Last contact 12/27 506 Adult Male 1,406 307 Last contact 2/18 532 Adult Male 1,249 307 Died 1/6 Wing (mm) Fate �31 Table 3 (cont.). Bird No. 568 Age Sex Weight (g) Adult Male 1,190 Wing (mm) 298 Fate Last contact 12/27 Movements Instrumented ducks were re-located 1,388 times in 1986-87 and 1,406 times in 1987-88. The time of telemetry fixes was skewed to evening in 1986-87 (Fig. 8), but nearly equally distributed throughout the day in 1987-88 (Fig. 9). Radio-marked birds dispersed in all directions from Chestnut Slough during both winters. In 1986-87, most telemetry locations were in the Chestnut Slough vicinity and eastward to Latham Reservoir, Beebee Draw and Milton Reservoir (Fig. 10). During 1987-88, radio-marked mallards were widely dispersed from around Windsor in the northwest, Lone Tree Creek in the northeast, Latham Reservoir in the southeast, and the St. Vrain River in the southwest (Fig. 11). Milton Reservoir received no use in 1987-88, but usage in the northeast portion of the study area increased markedly. Home range sizes, computed using the minimum area polygon method, differed among age/sex classes. In 1986-87, home ranges for adult male, adult female, immature male, and immature females averaged 219, 170, 131 and 94 ha, respectively (Table 4). Comparable home range sizes for 1987-88 were 133, 78, 126 and 141 ha (Table 5). Average overall home range sizes were 150 ha and 124 ha in seasons 1 and 2, respectively. Overall home range sizes using the Jennrich-Turner method with 95% confidence ellipses were 340 ha in 1986-87 and 233 ha in lSi:n -88, both considerably larger than those home ranges computed using the mL; 'llumarea polygon method (Tables 4 and 5). The shape of home ranges varied among birds, but often included heavily utilized wetlands that served as anchors or corners for minimum area polygons. In 1986-87, Chestnut Slough, Kodak ponds, and Seeley, Latham, and Milton reservoirs were important in delineating home range boundaries (Figs. 12-15). Kodak ponds, Latham Reservoir, Chestnut Slough and Norgren's Slough served the same functions in 1987-88 (Figs. 16-19). Home ranges of mallards commonly overlapped or in some instances included the entire range of another bird. Habitat Use Habitat use varied among birds in both 1986-87 (Table 6) and 1987-88 (Table 7). When unknown habitat type locations were eliminated and birds pooled within years, warm-water wetlands received the highest use in both years (Table 8). During the mild winter of 1986-87 portions of lakes and small ponds remained open, and these wetlands received considerable use by instrumented ducks (Table 8). In contrast, during 1987-88 many lakes and ponds were completely frozen, and duck use shifted to rivers, holding/sewage ponds and ditches (Table 8). Cornfield use decreased but feedlot use increased during 1987-88 compared to the previous year. �32 240 220 t/) 200 Z 0 180 i= <t 0 0 160 u, 120 140 ..J 0 0: 100 m 80 W :E ::) Z 60 40 20 0 0500 1000 1500 2000 TIME OF DAY Fig. 8. Hourly distribution of telemetry locations, 1986-87 t/) 120 Z 0 i= 100 ..J 80 <t 0 0 u, 0 0: 60 W m :E ::) 40 Z 20 0 0500 1000 1500 TIME OF DAY Fig. 9. Hourly distribution of telemetry locations, 1987-88 2000 �o a a + ~ =t* + 0# + + !of- + D a E .,..0 .lJt. c 33 •..o I: (II - III CJ .2 - .2 Q) E Q) •..>- G) td •.. til u:: �34 + o o + a o a o I ex) ex) " ex) en .•.. •.. VI C o o III ;:: o s CD >- -•.. I- E CD 'i ...• •... �i / '\ G a -. - ___ --_ ,," { o ~ o D 0 ~ ? r ~ ~ <:l pt::( ~ -} o N co ~ ~ o N o I I I I I ,.._ M co ci 35 ,.._ I co CD CO (1) ~ iii II) '0 ~ ~ CI) E II) E "5 '0 CI) (I) e II) - C'l t: II) E CI) ~ :::r::: e o tJ. C'l N - u: �36 L) o : G ,I ,( " , ,'I ,'1. \ / ./ /' • ,J ' .. : /.': '/ . /. : ;/ en CD ~ ~ ~ ~ ~ c:i CD co ('II • I I I I CD CD 0 ,... ('II o ('II . -----r.#f~~~ / "~,,.rr.:.':.~~1 ~ / . f /'/ / : .: oQ : : : . : . --!_ o P. o : : I / y' ;/: I ~, ;~: . 0 ;/ ,i /: / \',, /. \',/.' .i \'"/ ;/ E \' ,~: D ./ ~ ~ f\ I./~ ·I!l / '\\ . . 0 ,... I CD co CD (1) .•... o CI> g) (I) c: III •.. CI> •.. E o :::t M til u:: �4J rt "--t I , I I I I \ I ( )if tt) / (' \) /' a / / o q ( ,," " .- ;" 0 (8 /' r,-, II o ~: 1 /\. / e .. ~Jo~~/ o o ~ . : LO LO 'P'" 'P'" 37 Q) •..ftI c: Cl ~ (/) o - ............ [J .... o E o :I: �w 00 o ~ 1I '. o <> jl-~,_'_~~~ '. o _, c:::> -. o o " ~ r <> O\:J C> 0.816 ~h -- --- -L, " " 10 km ~)\ 0.900 ......... 0.916 Flg.15. Home ranges of Immature female mallards, 1986-87. 0.963 _ .._ ••_ 0.979 0.995 �I , ' .... " ~ ...... ..... Co (' .. ~ .... 'of ' ,/~,' ' ••• ''U . ,II' , ,': \ \'~. ~ \ ~. , • "'t:~;' I,' ~: t~\.. -.~ ././i ...\' '. ~ ~ \ ...~..... \' ,,;;., / .' ' _,/ ....::/ ':~A\,' ~\" \\0 ,I // ../'..... v., / »,> ".': 1/:'. 1-' f.• ' I I " \ ,' ., i": . \ , :.~ " \,," -1-. \ : : D : \~ :~"" l ~ ).' h<{J : !';.., ~ ~ ..~~------~ .".._".)( J ( ·\ "\1,! • \~ (I \ " "._'",,/' !) :,"..".","'/ ~,/ ,/ 1'('/ I if ,' ' (" /: ,'.) l:( I 'I -» " ', r/ ' I . , \' \ . _' / "f? G,' I \ \ :\ \ :~ '" G, ,./' (\' I • , • c ../>.:., 'l..' ,\ '.'. /', \ ~ ~~ ) , ' II ~ 'I": \-,.' of', / ,'1 V', ~" • : , : I i'· \ : , (• \ " i : \ \ \ ..,'/ . . r . \~' \~..,"'I o ,/ _..---,.,." , ," '.!,/ ,/,/ \t' (V / o . , }f' r;- -, '-1::;:- _0 0 t •""' ; r! r r } o co ci CD It) (\I ci C'? It) CD o ci It) o o M ci co (\I ci (\I I 39 aj co co "" O'l .•.. II) ... ('J '0 ('J E CLl E uS •... o ~ E LL �40 U o " _-/' ' I ~ : /: . : ~ . / :/ i/ • (J ,, ... " : : ' ~~:~ // ! ,I ) '" / (',1) 0 J . ,~ :, ., :: 0 '" . 1 . c- :. : '" ","" I' <:: f...... ',\.", ...,<-. .: ., , . ::':. i: '.: I I~: \. t: t \~,:. ::' : ,t.; ,:(: o ~D\ ~:~~--------------J "" .. I o o E 0 ~ 'P'" .__, o N •.... ci C') . IX) ex; ,....I 0 N N E I'D ~ a> ,... IX) ci I I I I o •.... 'P'" en o 'C I'D '3 CI.l -CI.l Cl C I'D •.. CI.l E o z Cl •..,... u: �) i · ; f I , I ~· .'.' · J it.,I. «, I \ I ' I Q I I a I .;.~ },'~\ ~~~ ~ ,~//' '~"'i~/": I <t ~ ' .:. r-.<~.~" { , ,I I.' II ~ c> 0 " ~a/~ "s, " " D " " 0 0 " ./ "" 0' ~ ' E ::.: o ", ' ~, o Q fl --.,~~-----•••• -' -or "", ',' ~ '\ ~" ~, ...' ~-J~,'''-\'''. "'. ~+-...f.1/ .,l . ,..:' .' ", =:': .-,-, "-: ~l '\, -' ! ~~ " o 0 o o CO) II) o CO) N .•.. o 41 CI> III E CI> ~ :J E III .5 - CI) .0 CI> til CI> c: III ~ E 0 X ... til ccS u:: �42 D D o o ('oj ci V o v ('oj ci o ci L() (Xl ci ('oj o OJ o ci cO (Xl ,....I (Xl OJ - o en CI) 01 C ,._III CI) o E z ai •... E LL �Table 4. 1986-87. Home range sizes of radio-marked mallards during winter, Home range size (Ian) Bird No. No. fixes Minimum area polygon method Jennrich-Turner method (95% ellipse) 816 40 146.5 285.0 837 113 328.9 858.1 862 66 90.8 177.7 887 54 137.7 195.2 900 23 0.1 0.3 916 46 159.9 492.6 946 105 455.0 842.2 963 10 1.2 4.9 979 43 127.5 351.9 995 64 129.8 312.9 1020 81 130.4 268.9 1063 16 0.6 1.3 1099 23 32.0 87.8 1111 57 141.2 372.0 1126 46 414.6 624.0 1155 13 4.5 29.4 1174 95 162.7 418.8 1189 54 209.7 519.4 1202 51 126.3 310.3 1232 71 214.5 441.6 1714 16 140.2 550.0 150.2 340.2 Means �44 Table 5. 1987-88. Home range sizes of radio-marked mallards during winter, 2 Home range size (km ) No. fixes Minimum area polygon method Jennrich-Turner method (95% ellipse) 048 79 143.5 139.0 090 120 432.0 380.7 128 114 87.1 76.5 150 55 28.4 36.1 170 11 3l.3 135.9 220 22 135.6 528.6 Bird No. , 240 20 6l.9 150.8 282 123 100.3 125.9 300 173 92.6 87.2 312 42 45.6 97.2 350 42 312.6 545.8 372 79 67.4 137.4 420 169 95.6 101.1 464 25 2.9 4.8 506 71 125.3 220.0 532 66 148.6 387.8 568 12 197.4 800.0 124.0 232.6 Means �Table 6. Habitat use by individual radio-marked mallards, 1986-87. Percentage of locations by habitat typeBird No. Unk. Pond Lake Hold. Gravel Warm-W. Ditch River Corn. No. obs. 92 102 9.8 31.5 1.1 0 0 22.8 0 29.4 5.4 816 6.8 4.6 20.4 0 0 63.6 0 4.6 0 837 5.6 9.5 36.5 0 0 39.7 0 1.6 7.1 126 862 13.9 11.4 1.3 0 0 54.4 1.3 12.7 5.1 79 887 20.0 7.1 2.9 0 0 62.9 0 0 7.1 70 900 11.5 3.9 84.6 0 0 0 0 0 0 26 916 18.3 0 5l.7 0 0 21.7 0 1.7 6.7 60 946 15.4 16.2 16.2 0 0 34.6 0 13.1 4.6 130 963 50.0 0 0 0 0 35.0 0 15.0 0 20 979 16.9 2.8 28.2 0 0 35.2 0 12.7 4.2 71 995 15.5 11.9 34.5 0 0 27.4 0 3.6 7.1 84 1063 18.2 4.6 0 0 0 63.6 0 13.6 0 22 1099-16.7 3.3 30.0 0 0 43.3 0 6.7 0 30 1111 11.6 10.1 60.9 0 0 10.1 0 2.9 4.4 69 7.1 5.4 7.1 0 5.4 60.7 0 3.6 10.7 56 1155 24.0 0 20.0 0 0 52.0 0 4.0 0 25 1174 14.3 25.9 20.5 0 0 30.4 0 2.7 6.3 112 1189 7.7 13.9 67.7 0 0 4.6 0 0 6.2 65 1202 11.4 12.9 17.1 0 0 41.4 0 12.9 4.3 70 1232 11.2 15.7 14.6 0 0 36.0 0 9.0 13.5 89 0 0 0 0 0 0 0 0 2 1126 1249 100 44- �46 Table 6 (cont.). Percentage of locations by habitat type· Bird No. Unk. Pond Lake Hold. Gravel Warm-W. Ditch River Corn. No. obs. 1714 40.S 7.1 23.8 0 0 23.8 0 4.8 0 42 1733 SO.O 0 0 0 0 0 0 SO.O 0 4 •Key to habitat abbreviations: Unk. - unknown habitat type Pond - Small ponds/reservoirs; Lake - lakes; Hold. - holding/sewage ponds; Gravel - gravel pits; Warm-W. - warm-water wetlands; Ditch - ditches; River - rivers; Corn. - cornfields. Table 7. Habitat use by individual radio-marked mallards, 1987-88. Percentage of locations by habitat type· Bird No. Unk. Pond Lake Hold. 'Warm-'W.Ditch River Corn. Feed. No. obs. 30 50.0 30.0 20.0 0 0 0 0 0 0 10 48 13.8 2.3 1.2 0 65.5 6.9 10.3 0 0 87 49 0 0 0 0 0 100.0 0 0 0 1 SO 0 0 0 0 100.0 0 0 0 0 3 70 75.0 0 25.0 0 0 0 0 0 0 4 90 7.5 17.9 2.2 0 53.7 4.5 6.7 3.0 4.5 134 109 33.3 0 33.3 0 0 33.3 0 0 0 3 128 8.7 3.9 0 0 4.7 7.9 52.8 1.6 20.5 127 ISO 3.S 1.8 14.0 0 66.7 1.8 12.3 0 0 S7 170 0 0 0 0 30.8 23.1 46.2 0 0 13 0 0 0 0 0 0 0 0 2 . 184 100.0 220 13.3 13.3 0 0 63.3 0 10.0 0 0 30 240 0 4.8 19.1 0 57.1 4.8 9.5 4.8 0 21 , �47 Table 7 (cont.). Percentage of locations by habitat type· Bird No. Unk. Pond Lake Hold. lJarm-lJ.Ditch River Corn. Feed. No. obs. 266 o 100.0 0 0 0 0 0 0 0 1 282 2.2 0 2.2 0 91.8 0 3.7 0 0 134 300 2.8 32.6 0.6 0 32.0 2.8 13.3 13.3 2.8 181 312 12.0 16.0 0 2.0 56.0 4.0 8.0 2.0 0 50 330 50.0 0 0 0 50.0 0 0 0 0 2 350 12.2 42.9 2.0 0 26.5 2.0 10.2 4.1 0 51 360 100.0 0 0 0 0 0 0 0 0 1 372 7.3 6.1 11.0 0 51.2 2.4 4.9 17.1 0 82 392 25.0 0 62.5 0 0 0 12.5 0 0 8 400 0 0 0 0 100.0 0 0 0 0 1 420 3.9 16.9 0 0.6 52.3 0 14.0 12.4 0 178 438 18.2 0 45.5 0 18.2 0 9.1 9.1 0 11 464 3.7 0 81.5 0 3.7 7.4 3.7 0 0 27 506 19.6 0 5.4 35.9 17.4 1.1 10.9 0 9.8 92 532 5.5 46.6 4.1 0 39.7 0 2.7 1.4 0 73 568 27.3 18.2 22.7 0 31.8 0 0 0 0 22 •Key to habitat abbreviations: Unk. - unknown habitat type Pond - Small ponds/reservoirs; Lake - lakes; Hold. - holding/sewage ponds; lJarm-lJ.- warm-water wetlands; Ditch - ditches; River - rivers; Corn. - cornfields; Feed. - feedlots. �48 Table 8. Habitat use by radio-marked mallards 1986-87 Habitat type during 1986-87 and 1987-88. 1987-88 No. locations No. locations , Small ponds/reservoirs 167 14.0 204 15.8 Lakes 344 29.0 79 6.1 o o 35 2.7 3 0.3 o o 488 41.0 627 48.6 0.1 42 3.2 108 9.1 186 14.4 77 6.5 72 5.6 o o 46 3.6 Holding/sewage Gravel ponds pits Warm-water Ditches Rivers Cornfields Feedlots Totals wetlands 1 1,188 100.0 1,291 100.0 Differences in habitat use were apparent when instrumented birds were pooled by age and sex class. In 1986-87, adult males used warm-water wetlands more than other age/sex groups (Table 9). Females used lakes more frequently than males, and were located in cornfields more often than birds of other age/sex classes. During both field seasons, adults made greater use of riverine habitat than did immatures. In 1987-88, adult males used small ponds and reservoirs more than other age/sex groups, whereas immature females made greater use of rivers (Table 10). Temporal changes in habitat use, mostly in relation to the availability of ice-free wetlands, are apparent when use data are summarized by month. Lakes and small ponds/reservoirs received use whenever these habitats were ice-free, as they were in December, January and February 1987 (Tables 11 and 12). However, when temperatures were coldest, warm-water wetlands received their highest use. Use of rivers was nearly constant across months and years except for a large increase in use during February 1988. Ditches were used infrequently during early and late winter, 1987-88. Mallards used feedlots only during January and February 1988 (Table 12). �49 Table 9. Mallard habitat use by age-sex class during winter, 1986-87. , , , , 1m, male No. obs. Habitat type Ad, bmale No. obs. Ad, male No. obs. 1m, flilma1e No. obs. Unknown 73 14.2 24 8.1 52 17.1 51 18.8 Small pondsj reservoirs 61 11.8 45 15.2 15 4.9 46 16.9 131 25.4 51 17.2 111 36.4 51 18.7 0 0 3 1.0 0 0 0 0 184 35.7 119 40.2 96 31.5 89 32.7 1 0.2 0 0 0 0 0 0 Rivers 40 7.8 34 11.5 18 5.9 16 5.9 Cornfields 25 4.9 20 6.8 13 4.3 19 7.0 Lakes Gravel pits Warm-water wetlands Ditches ·Co1umn percentage Table 10. Mallard habitat use by age-sex class during winter, 1987-88. , Habitat type Ad, female No. % obs. Ad. male No. obs. 1m, female No. % obs. 1m, male % No. obs. Unknown 14 10.0 40 7.9 32 6.1 31 13.4 Small pondsj reservoirs 10 7.1 97 19.1 61 11.6 36 15.6 Lakes 14 10.0 19 3.7 20 3.8 26 11.3 Holding/sewage ponds 0 0 33 6.5 1 0.2 1 0.4 Warm-water wetlands 67 47.9 233 45.8 222 42.2 103 44.6 Ditches 5 3.6 7 1.4 18 3.4 12 5.2 Rivers 15 10.7 41 8.1 111 21.1 19 8.2 Cornfields 15 10.7 25 4.9 29 5.5 3 1.3 0 0 14 2.7 32 6.1 0 0 Feedlots Column percentage �50 Table 11. Mallard habitat use by month during winter, December Habitat type No. obs. Unknown 1986-87. January % • No. obs. February % No. obs. % 131 21.4 53 3.8 16 15.0 31 5.1 79 18.7 57 16.2 104 17.0 57 13.5 183 52.0 0 o 3 0.7 o o 277 45.2 194 45.9 17 4.8 1 0.2 o o o o Rivers 49 8.0 33 7.8 26 7.4 Cornfields 20 3.3 41 9.7 16 4.6 Small ponds/reservoirs Lakes Gravel pits Warm-water wetlands Ditches Column percentage Table 12. Mallard habitat use by month during winter, December 1987-88. January February a Habitat type No. obs. Unknown No. obs. % % No. obs. % 71 10.1 28 6.4 19 7.1 170 24.2 27 6.1 7 2.6 79 11.3 o o o o 7 1.0 25 5.7 3 1.1 289 41.2 245 55.7 93 34.8 Ditches 25 3.6 11 1.4 6 4.1 Rivers 51 7.3 41 9.3 94 35.2 Cornfields 10 1.4 38 8.6 24 9.0 o o 30 6.8 16 6.0 Small ponds/reservoirs Lakes Holding/sewage Warm-water ponds wetlands Feedlots Column percentage �51 Response to Hunting Disturbance Responses to hunter disturbance were recorded for 15 radio-marked birds at Chestnut Slough from 13 December 1986 to 3 January 1987 (Table 13). Gross analysis indicated little difference in the age/sex proportion of usable radio-marked birds within the study area using Chestnut sometime during the hunting season (3 of 4 AM, 6 of 7 AF, 3 of 31M, 3 of 5 AF), although adult females seemed more likely to return to the Chestnut roost following disturbance. Table 13. Presence or absence of radio-marked birds at Chestnut Sloughs on consecutive days during and following disturbance at Chestnut, 1986-87 (P - Present, A - Absent) Date December Bird January Age/Sex AM AF 1M IF • a No. 13 14 15 837 1126 1063 P P P a 20 21 a a 27 22 28 29 A P A P a 3 4 A P P A A A A A A P A P P P A A A A P b P P P P P P P P P P ~c A A A A A A A A P P P A A A A A P b P P A A A P P A A A P P A A A A A A A A A A P P A A A A A A A A A P A A A P A A P A A A A P P A A A A 862 887 1202 1099 946 1111 A A 1174 1155 1232 P P A A P A A 979 916 963 P A A P P P P P P P P A P P A A P No hunting on Chestnut bDeparted Chestnut prior to any disturbance cHarvested A A A A A A A A A A A b �lJ1 N TABLE 14 • Hunting season disturbance birds at Chestnut Sloughs 1986-87. factors (see methods), bird reaction Disturbance Age/Sell AM Bird No. 0.837 Date 12113 12114 12120 1.126 1.063 AF 0.862 0.887 1.202 AF .. 1.099 0 * * 1 28 7 12113 12114 12127 12128 12/13 12114 U Accu.ulated rating before departurt! Hours before return 40 7 3 10 11 >25$.203 111 9 10 7 23* 1 1 26 3 10 Harvested 3 18 U U 6 21 7 0 11 )22910 )11522 10 * 2* 1 7 1 1 1 113 22 11 2 92 10 11 5.600 7 1 1 1 43 21 13 1 10 $..202 10 1 1 8 4 * 28 19* U 12121 2* 12/13 12114 12120 s 3 2 * 4 6* 4* 12120 12/13 12/14 12/20 3 1 12127 12128 12/14 12120 2 and roost homing for radio-marked * 28 * 2 18/ 4 U B* U 11 HarvestE.·d �Disturbance AgelSex Accu.ulated rating before departure 0 1 2 3 0.946 12114 12128 1/3 * 19 1 1 24 0 0 1 3 0 1.174 1.155 ,1.232 IF 5 Date 1.111 1M 4 Bird No. 0.979 12127 12128 12113 12/14 12120 * * * 22 18 12121 12128 12/13 12114 12121 12127 1/3 3 2* * 1 U 1 * 12113 12121 6* U U 3 * U 9 11 11 <24 Did not return 11 10 ~672 953 Did not return 2 3 948 6 10 10 90 1 1 21 2 3 3 1 2 * * 6 2 2 18* 37 21 3 Hours before return 8 11 10 0.916 12/14 17 U 20 10 0.963 12/14 17 U 20 10 \J1 W �Vt "" TABLE 15 • Hunting season disturbance Chestnut Sloughs 1987-88. factors, bird reaction and Disturbance Age/Sex AM Bird No. 0.532 Date 12126 112 1/2 112 5 * AF 0.438 12112 * 1M 0.0L!8 12113 12113 1211L! 12115 12117 12/18 12119 12/20 12121 12122 * * * * * * * 0.350 0.312 12112 12113 12126 12117 12118 12119 12120 12121 12123 12128 1 0 2 3 4 5 4 3* 1 1 4 U 2 2 U 2 4 3 3 ** * * * * * ho.ing for 1 1 1 1 1 1 U 1 5 3 '1* 5 U radio-IIIarked birds Acculllulated rating before departure 35 4 28 45 0 U * roost at Hours before return >96~166 0.25 3 <18 Did not return 7 1 Did not leave 0 3 0 0 0 36 0 0 5 >115.28 11 ~11 90 ~4 90 >24916 5 8 0 >240912 8·· Did not return 0 0 0 0 0 11 11 11 >10<12 o· >7920 0 3'1 Did not return (Found dead) �II' c: ~ :s QI +J QI QI +J :s ~ .II) QI ~ 0 ~ ~ ~ :s 0 % 0- ...•c: ~ ~ 'II +J 'II QI '1:) CL. QI QI '1:) +J ...•'II ..., o::r :s ~ E 0 :s ~ u QI u .&J ~ QI u c: :s I. 'II .&J 1/1 N .... +J II:> o o :z '1:) ..•~ al :s c: ~ ~ +J 0 Q '1:) ...• e 0 +J QI o::ro .... vi o::r ..., N "- Oo::r * .... * * N N en N ....•.. N ...• ...• N "_ ...• o c;r N . o 0- o . o o 55 �56 Eight birds (1 AM, 4 AF, 21M, 1 IF) were present on Chestnut during the opening morning of the hunting season (Table 14). Two adult males (887, 1202) remained on the area throughout all disturbance although they left the area on an afternoon feeding flight. Birds were tolerant of shooting that occurred off of Chestnut Slough but could be heard on Chestnut (disturbance factor 1), since only 1 response was noted in 116 occurrances. Hunters driving in vehicles (disturbance actor 3) resulted in 3 of 7 birds leaving. Two of 4 left in response to shooting on Chestnut >200 m away from the birds (disturbance factor 2). Four birds (Table 14) were generally tolerant of all disturbance types recorded on opening day. No birds returned to Chestnut during daylight hours, but all but 1 bird (1M 1155) returned for night roosting. On 14 December 1987, 3 of the 5 birds remaining on Chestnut that had been present on 13 December responded to hunters driving in; 2 of the same birds had responded in the same manner on 13 December. Birds experiencing their second consecutive day of disturbance were less tolerable of minor disturbances, with all birds leaving prior to any shots being fired on Chestnut. Four birds experiencing their first day of Chestnut disturbance (1063 AM, 946 AF, 916 IF, 963 IF) responded in a similar manner, although the last 2 birds to leave were among this group_ No birds returned to Chestnut during daylight hours, but again all but 1 bird (862 AF) returned there to roost at night. Hunting occurred at Chestnut on 17 December, 1987 but monitoring of bird/hunter interactions did not. Six birds (2 AM, 3 AF, 11M) were on Chestnut on the morning of 12 December 1988. Five of six experienced at least their third disturbance bout on that day. Three of 6 birds left the area in response to the initial disturbance which was hunters driving into the area. None of the 3 birds had left in response to eriving in previous bird/hunter interactions, indicating a "learned" response. A fourth bird left shortly after "drive-in" with no disturbance evident, while a fifth bird left when the first shots were fired away from Chestnut. A sixth bird (AF 1202) which had been very tolerant of dist~rbance the previous weekend remained on Chestnut throughout the hunting bout (Table 14) but left later in the day. Only one (AF 887) of the 6 birds returned to Chestnut for night roost; 2 were shot by hunters, and 3 were noted on Chestnut again for about one week, including the bird that was tolerant of disturbance (AF 1202). Two birds (1M 1232, IF 979) joined 887 on the night roost on 20 December 1986. Immature male 1155 arrived about 0.5 hours before sunrise on 21 December, 1986. There were no hunters on Chestnut on 21 December, 1986. Bird 1155 left in response to the second occurrence of shooting away from Chestnut and eventually left the study area without returning to Chestnut. The remaining 3 birds experienced no additional ~isturbance and remained on the area for at least 2 hours before departing. The latter 3 birds were not noted on Chestnut for a considerable amount of time after their 21 December departures (Table 14), but monitoring of birds on Chestnut was sporadic during the latter part of December. Birds were hunted but no monitoring occurred on 23, 24 and 25 December, 1986. Even though considerable disturbance occurred at Chestnut prior to the next monitoring session on 27 December, 4 birds were present on that morning. Two of the birds (AM 1126, AF 1111) were first noted at Chestnut on the afternoon of 26 December 1986 and may not previously been subject to disturbance at Chestnut. Adult female 862 had not been noted at Chestnut for about 2 weeks and the previous Chestnut occurrence noted for 979 was on 21 �57 December. All birds tolerated the initial drive-in by hunters but began to leave within 5 minutes after drive-in and before additional disturbances. One of the "new" birds (1111) left early while the second (1126) tolerated about 40 minutes of sporadic disturbance and was the last of the 4 birds to leave. All 4 birds returned to Chestnut after dark along with 947, but 979 left after about a 10 minute stay. On 28 December 1986, 3 of 5 birds left about 20 minutes before sunrise prior to any disturbance. Bird 1232 left when hunters drove in about 1 1/2 hours after sunrise, but 1126 tolerated some shooting on Chestnut before leaving when shots were fired close by. All birds except 1111 returned that evening. Two birds (862 and 1232) returned before sundown but left again within 20 minutes and only 1232 returned. Bird 947 which returned about 40 minutes after sunset left about 15 minutes later, leaving only 1126 and 1232 at roost on Chestnut from the original morning disturbance group. Chestnut was very attractive to radio-marked birds on the evening of 28 December as 4 other birds also roosted there. On 3 January 1987, 946 was the only bird on Chestnut, and it left before any disturbance, about 40 minutes before sunrise and returned about 40 minutes after sunset. Radio-marked birds continued to use Chestnut Slough through the 13 December - 3 January 1986-87 period in spite of disturbance, although the number of birds using the area declined as the season progressed (Table 14). Fifteen marked birds experienced a total of 31 disturbance/days (1 bird disturbed on 1 day) throughout the period. Those birds returned to the Chestnut roo;;t.generally within 10 hours following 81% of those disturbances (after Table 14). Only 2 birds (87%) failed to return to roost following their first exposure to disturbance while 3 of 11 (79%) did not return following their second bout with Chestnut disturbance. With one exception, the birds did not return to Chestnut within the same daylight period following disturbance. Radio-marked birds did not choose to remain on Chestnut exclusively when not disturbed. In 3 instances marked birds left Chestnut before any disturbance occurred and 13 departures took place after some disturbance. Although the departures took place after some disturbance, the departures were not recognized as a responses to a specific disturbance. The period of disturbance monitoring followed a short period of abnormally cold temperatures but was characterized by moderate temperatures. Responses to hunter disturbance were recorded for only 7 radio-marked birds at Chestnut Slough from 12 December 1987 through 2 January 1988. Only 9 radio-marked birds (2 AM, 2 AF, 31M, 1 IF) were recorded on Chestnut during the hunting season, and 2 of those were thought to be behaving atypically. Attempts to monitor early morning hunter and bird activity occurred on 17 of 22 mornings at Chestnut. Because of the absence of radio-marked birds and early morning hunting and the movement of birds away from the Chestnut roost before any disturbance, disturbance/bird interactions were recorded for only 8 bird-days during the 1987-88 period. By leaving the roost site early and returning after dark, 3 of 7 birds using Chestnut never experienced any hunting disturbance (Table 15). Early morning departures were typical of immature male 312 which roosted on Chestnut 7 nights in late December. Immature male 48 left the roost before disturbance on 5 of 9 days in mid to late December. Those birds experiencing harassment on Chestnut usually left after minor disturbance except on 13 December (1M 48), 20 December (1M 48), 26 December (AM 532, 1M 350) and 2 January (AM 532, IF 90). The later 2 days had �58 temperatures below 0° F. Adult male 532 returned to Chestnut after leaving in response to disturbance~ twice on 2 January. In contrast to birds monitoreu Uuring the 1986-87 season, 1987-88 birds in general used Chestnut Sloughs le~s .nd .ere less tolerant of disturbance. Whereas a greater use of Chestnut and more tolerance of disturbance by 1987-88 birds would have been predicted, given the colder temperatures (Fig. 2) and greater snow cover (Fig. 5) during 1987-88. Behavior Time budget observations totaling 4,759 minutes were obtained on 4 wetland habitat types during 1986-87 and 1987-88 (Table 16). Observation times were similar within pair status-sex-habitat categories. Resting was the most common activity each winter, followed by swimming (Figs. 20 and 21). Time devoted to preening was constant both years, but water feeding decreased in 1987-88 while courtship and other activities increased. Males and females behaved similarly in 1986-87 (Fig. 22), but in 1987-88 females spent more time in courtship and less time swimming than did males (Fig. 23). Table 16. Behavioral observation time by hai>itat type, sex, and pair status. 1986-87 and 1987-88. Observation Time (min.) Habitat Sex Status Reservoir Female Paired Unpaired Paired Unpaired 312.1 287.1 244.8 288.2 Paired Unpaired Paired Unpaired 453.0 236.6 521.1 286.6 Paired Unpaired Paired Unpaired 306.0 302.6 246.7 427.9 Paired Unpaired Paired Unpaired 261.6 158.2 165.7 260.5 Male Riverine Female Male 'Warm-water Female Male Female Other Male Total 4,758.7 Behaviors differed among habitat types, but a habitat-year interaction �59 Fig. 2O. Time budget for all mallards, 1986-87. Rest Swim Preen Water Feed Fig. 21. Time budget for all mallards, 1987-88. Courtship Other �60 Fig. 22. Time budget for females (left) and males (right) 1986-87. Rest Swim Preen Water Feed Courtship Fig. 23. Time budget for females (left) and males (right) 1987-88. Other �61 • Re.t ~ Re.ervolr. Warm-waters River. ~ Swim Preen ~ Water Feed IQQ Court.hlp rza Other Others Fig. 24. Time budgets by habitat type, 1986-87 . • Rest ~ Re.ervolr. River. ~ ~ ~ rza Warm-waters Other. Fig. 25. Time budgets by habitat type, 1987-88. Swim Preen Water Feed Courtship Other �62 • Rest ~ Wj ~ Jan. 1987 F.b.1987 Fig. 26. Time budgets for Jan.• nd Feb. 1987. Dec. 1987 Swim Preen Water Feed 50j Courtship rza Other • Rest ~ Swim ~ Preen ~ Water Feed ~ Courtship o Other Jan. 1988 Feb. 1988 Fig. 27. Time budgets for Dec., Jan.• nd Feb. 1987-88. �63 was apparent (Figs. 24 and 25). Generally, warm-water wetlands were used for resting more than other wetland types. Courtship displays were most common on reservoirs and warm-water wetlands. Water feeding, common on reservoirs and rivers during 1986-87, was less apparent ~n these habitats in 1987-88. Monthly time budget summaries indicate temporal changes in behavior. During 1986-87, February behaviors included more resting but less water feeding than in January (Fig. 26). Courtship behavior was most common in December 1987 and January 1988, but decreased in February 1988 (Fig. 27). Swimming decreased whereas water feeding and preening increased from December through February, 1987-88 (Fig. 27). DISCUSSION Differences in snowfall and temperature regimes between the two field seasons affected habitat availability on the study area. Consequently, mallard habitat use and behavior differed between years. During 1986-87, when most wetlands remained unfrozen due to mild temperatures, home range size was larger than in the colder winter of 1987-88. With fewer wetlands available, birds reduced the number and frequency of their movements. In Nebraska, size of activity centers (home ranges) differed between adult and immature female mallards (Jorde 1981). However in 1986-87, all age-sex groups appeared to differ in home range size. In 1987-88, immatures occupied larger home ranges than adults. Jorde (1981) found that immature males and females occupied activity centers 27.8% and 28.2% larger than their adult counterparts, respectively. Nebraska mallards occupied primary activity centers ranging from 210 to 842 ha. These values are similar to the home range sizes of mallards reported here. Relative to their availability (0.6% o£ the sur£ace water area), warmwater wetlands were highly selected by radio-marked uallards in both winters. Jorde et al. (1984) speculated that such areas may provide thermal refugia important for minimizing thermoregulatory energy loss. Surprisingly, maximum air temperatures 5 cm above the water surface at Chestnut Slough, a warm-water wetland, were slightly lower than ambient air temperatures 1.5 m above the ground (Fig. 28). Minimum temperatures at 5 cm height were, however, warmer than-ambient conditions. Thus, in this instance a thermal advantage was realized only during late night and earl~ morning periods when diurnal temperatures were at a minimum. Nevertheless, water temperatures at 15 cm subsurface depth were always well above air temperatures (Fig. 29), thereby providing a favorable microclimate for minimizing heat loss (eg. Kilgore and Schmidt-Nielsen 1975). These data suggest that aside from simply providing water, warm-water wetlands provide a thermal habitat beneficial to wintering waterfowl. Mallards respond to a hierarchy of habitat selection that, at its highest levels, is dependent upon the availability of ice-free wetlands weighted by such disturbance factors as hunting (Ringelman et al. 1989). When weather allows, mallards preferred lakes and $mall ponds over rivers, holding ponds and ditches. Under snowfree conditions, ducks preferred to feed in cornfields rather than feedlots. However, mallards showed plasticity in their response to these and other conditions, adapting their movements and behavior to shortterm weather events. Temporal and spatial variability in habitat use may also relate to social events that occur during winter. Most mallards establish pair bonds during mid-winter in Colorado, and wetlands such as lakes and warm-water sloughs are �64 60 -u, W 40 a: ::J t~ a: w 0. ::E w t- . 30 I I I 20 , • • ,_ , " ,;, 'I I. I ' ~ ,'I II , 10 • " : .' " • " I' , • I' , I' .' .' , i ,'. I. I~'I,. I ~ I •• • I " 'I I,' '• ,I ,. I • • " ••••• I I " ~ ,""'''..' " __ ~~~ ,I \ " '. • 1" • __ , '. 1 I I I -10 ,,' 10 1 >" _-. , .~ I,' I • .: 1 30 I , • t '. i,. " •, I ~~~~ ',. 20 Dec. ". ,I I .' ,I,. 11 f' II , • • I '. ':. " , .' • •• I I' .' !: __ ~_L_~~~ • O .1 II .' ,. •••.• . , • • ' ~~ _ .' " ., ' I I 20 10 30 20 Feb. DATE Fig. 28. Maximum and minimum dally temperatures 5 em above the water at Chestnut Slough, 1987-88. 60 -- .' 50 ,, '' U. W , 40 a: ::J t~ 30 w 20 ::E w 10 a: 0. t- I '. ,'"" - ~, ..... '" , •.'... ',_, ,', " ~ '\ ' ",,,\ I I' " , " ",,"'''' ,•. -----------------~--~-----~------',' , •.•._ ,'---' , ...' ...--,' I, ' ••...."', ,--, '---",," O -10 11 20 Dec. 30 10 .20 30 DATE Fig. 29. Maximum and minimum dally temperatures 15 em under water at Chestnut Slough, 1987-88. 10 20 Feb. �65 thought to provide ·courtship arenas" for mallards on the High Plains (Ringelman et al. 1989). After pairing, mallards vacate such wetlands in favor of locations that provide greater isolation from conspecifics. Since adult male mallards outnumber females in Colorado and competition for mates is acute, extensive use of lakes and ponds by adult male mallards in 1987-88 may reflect the role of these wetland types in the social behavior of mallards. Behavior of mallards differed between years, but in general was dominated by resting (includes sleeping), swimming, water feeding and preening. Jorde et a1. (1984) found that mallards wintering in Nebraska behaved similarly, with behaviors dominated by sleeping, water feeding and preening. Resting, swimming and preening also dominates the behavior of mallards wintering in Oklahoma (Gordon 1977). As with habitat use, time budgets reflect social changes occurring in the mallard population. For example, courtship behavior remained high during December and January of 1987-88, but declined in February when numbers of unpaired birds presumably declined. LITERATURE CITED Altmann, J. 1974. Observational study of behavior: sampling methods. Behaviour 49:227-267. Dwyer, T. J. 1972. an adjustable radio-package for ducks. Bird-banding 43:282-284. Fenneman, N. M. 1931. Physiography of the western United States. Hill Book Company, New York and London. 534pp. McGraw- Gittings, E. B. 1941. Climate of Colorado. Pages 798-808 in Yearbook of Agriculture: Climate and Man. U.S. Dep. Agric., Washington, D.C. Gordon, D. H. 1981. Condition, feeding ecology, and behavior or mallards wintering in northcentral Oklahoma. M.S. Thesis, Oklahoma State University, Stil-1water. 68pp. Jorde, D. G. 1981. Winter and spring staging ecology of mallards in south central Nebraska. M.S. Thesis, Univ. North Dakota, Grand Forks. 116pp. Jorde, D. G., G. L. Krapu, R. D. Crawford, and M. A. Hay. 1984. Effects of weather on habitat selection and behavior of mallards wintering in Nebraska. Condor 86:258-265. Kilgore, D. L., Jr. and K. Schmidt-Nielsen. 1975. feet immersed in cold water. Condor 77:475-517. Heat loss from ducks Ringelman, J. K., W. R. Eddleman, and H. W. Miller. 1989. High plains reservoirs and sloughs. Pages in L. M. Smith, R. L. Pederson, and R. M. Kaminski, eds. Habitat management for migrating and wintering waterfowl in North America. Texas Tech Press, Lubbock. Szymczak, M. R. , and J. F. Corey. 1976. Construction and use of the �66 Salt Plains duck trap in Colorado. Tacha, T.C., P.A. Vohs, and G.C. Iverson. 1985. A comparison of interval and continuous sampJing methods for behavioral observations. J. Field Ornithol. 56:258-264. Prepared b~ l(~ ~Ringelman Yildlife Resear:::I , ��Colorado Division of Wildlife Wildlife Research Report December 1988 JOB PROGRESS REPORT State of __~C~o~l~o~r~a~d~o~ Project 01-03-212 (W-88-R) Work Plan 1 : Job _ Avian Research - Migratory Birds 18 Job Title: Winter survival and reproductive success of female mallards' Period Covered: Author: 01 January 1987 through 31 March 1988 James K. Ringelman Personnel: D. R. Anderson, J. Armstrong, J. Boulanger, K. Frye, D. Gilbert, M. Gilbert, W. Schraeder, Colorado Cooperative Fish and Wildlife Research Unit; C. Jeske, S. Borthwick, R. Knight, J. Laake, E. Rexstad, R. Scarpella, T. Shenk, D. Smith, J. Schmutz, K. Wilson, Colorado State University; J. Corey, R. Hopper, M. Szymczak, Colorado Division of Wildlife; R. Croft, R. Kirby, M. Nail, U.S. Fish and Wildlife Service. ABSTRACT Adult female mallards were captured and radio-marked in the San Luis Valley, Colorado, to assess (1) the magnitude of winter mortality, and (2) the relationship between winter body condition and subsequent reproductive performance. Hens were assigned to either the "good" (upper one-third of the condition range) or "poor" (lower one-third of the condition range) condition groups based on an index to fat reserves. In 1987, 105 mallards were instrumented with back-mounted transmitters, then located from the ground or air weekly. Of the birds marked in January, twenty-eight good condition and 37 poor condition hens died during 17 January through 4 July" for minimal mortality rate estimates of' 0.538 and 0.699, respectively. Mortality rates for, females instrumented in February were 0.277 for females in "good" condition'and,0.588 for females in "poot" condition. Of 31 instrumented'birds in the SanLuf.s Valley during May, only 2 females were known to have nested. In 1988, back-pack radio transmitters were affixed to 189 adult female mallards. from January through March. Most radios were applied to females in the upper or lower third of the condition index distribution. No differences in survival rates of females in "good" and "poor" condition were detected. A pooled 70-day survival rate of 0.279 was observed. Two of the instrumented females nested. Fate of 1 nest was unknown, the other was destroyed by avian predators. Instrumented females were collected from 2-5 weeks after instrumentation to determine effects of instrumentation on weight dynamics. Of 40 females collected, only 2 had gained weight, and some had lost a substantial percentage of their initial weight. Increased search effort over 1987 and an outbreak of avian cholera allowed us to collect 4,195 mallard carcasses, of which 900 were analyzed for lipids in the ulna. Ulna lipids indicated that 6.7% of the carcasses analyzed had depleted body lipids at the time of death. �69 YINTER SURVIVAL AND REPRODUCTIVE SUCCESS OF FEMALE MALLARDS James K. Ringe1man Michael R. Szymczak This report documents the accomplishments of 2 field seasons, 1986-87 and 1987-88. Parenthetical references to years refers to objectives, methods, or results from a single field season. The absence of such a reference implies objectives, methods, or findings common to both field periods. P. N. OBJECTIVES 1. Quantify winter survival rates of adult female mallards good condition. 2. Determine the sources of winter mortality Luis Valley. 3. Investigate the relationship between winter body condition and reproductive performance of mallards wintering in the San Luis Valley. 4. Measure the winter energy balance of mallards by quantifying components of energy acquisition and depletion. for mallards in poor and in the San SEGMENT OBJECTIVES 1. Capture and radio-mark a minimum of 50 "poor" and 50 "good" condition adult female mallards in the San Luis Valley during January. 2. Quantify differences trapping. 3. Affix nasal saddle markers (1986-87) and wing bands (1987-88) to mallards to assist in behavioral observations and mortality estimations. 4. Measure the effects of radio instrumentation mallards (1987-88). 5. Conduct scheduled ground and aerial tracking to locate dead, radiomarked birds in winter and nesting birds in spring. 6. Measure clutch parameters mallards. 7. Collect remains of marked and unmarked carcasses, causes of mortality in the carcass sample. 8. Measure the standard metabolic rate of mallards, and perform digestion trials to assess the digestible energy of mallard foods. in mallard condition by age, sex, and date of on weight dynamics of and record nesting history of radio-marked and partition �70 9. Conduct winter counts of raptors to assess their temporal abundance and potential relationship to mallard mortality. STUDY AREA This study was conducted in the San Luis Valley (SLV), located in south-central Colorado (Fig. 1). The SLV is a 12,960 km2 intermountain basin, bounded by the San Juan Mountains to the west and the Sangre de Cristo Range to the east. As a result of the surrounding mountains and 2,286 to 2,438 m elevation, January temperatures average -4 C, and snow and ice fog are common. Upland areas are dominated by greasewood (Sarcobatus vermiculatis) and. rabbitbrush (Chrysothamnus spp.). Common wetland vegetation includes baltic rush (Juncus balticus), cattail (~ latifolia), hardstem bulrush (Scirpus acutus), coontail (Ceratophyllum demersum) and pondweeds (Potamogeton spp.). Further descriptions of the SLV can be found in Hopper et al. (1975) and Szymczak (1986). An average of 14,700 mallards winter in the SLV (1982-84 average, Colo. Div. Wildl., unpubl. data), with most residing on the Monte Vista National Wildlife Refuge (MVNWR). MVNWR is 5,670 ha in area and has over 200 ponds and impoundments. Wintering ducks are concentrated on those water areas which do not freeze as a result of continuous pumping or artesian flow. Mallards breed throughout the SLV and surrounding mountains (Rutherford and Hayes 1976, Szymczak 1986), but nesting is concentrated on the MVNYR (pers. obs.). METHODS Capture - 1986-87 and Instrumentation Mallards wintering on the MVNWR were captured with Salt Plains bait traps (Szymczak and Corey 1976) 17-20 December 1986, 5-14 January, 20-22 February, 5 and 18 March 1987. Each bird had its absolute and relative lipid stores assessed, it's condition index (Ringelman and Szymczak 1985) computed, and molt status scored for adult females. Most captured birds were classified by age and sex, then banded with standard USFYS leg bands. Adult females were assigned to 1 of 3 condition classes based upon their condition index relative to the distribution of the population in the SLV. Population distribution was determined by ordering the condition indices of each age-sex class on the first trapping day. Birds with a condition index in the upper 33% of the population were termed in "good" condition, while those in the lower 33% were considered to be in "poor" condition. A sample of 52 adult females in "good" condition and 53 adult females in "poor" condition were radio-marked with 26-g transmitter packages attached with a Dwyer harness (Dwyer 1972). High mortality of instrumented birds allowed another sample of adult females to be instrumented in February. The same procedure was followed in February, with 18 adult females in "good" condition and 17 in "poor" condition being instrumented. Radios were placed on females with condition indices less than 12.5 and greater than 14.0 in January. In February, the limits were set at 14.0 and 16.5. The February sample was treated separately from the January sample. In January, 100 each adult males, immature males, and immature females were marked with nasal saddles (Greenwood 1977) depicting their condition: , �ngood" ("+" saddle) or "poor" ("0" saddle). Birds in "average" condition were not marked. Approximately 60 adult females which were not instrumented were marked with nasal saddles. For the first three age-sex classes mentioned, criteria for determining which birds were marked were similar to those for radio instrumentation. Adult females marked with nasal saddles were in the middle 33% of the population and birds above and below the median were marked appropriately. These birds were used for focal animal time budget observations (Altmann 1974) when they could be located. Radio Tracking From 17 January through 1 May, instrumented birds were located from the ground or air weekly. Ground tracking employed scanning receivers with a 14element directional antenna or a 3-element null peak antenna. Aerial tracking utilized a Cessna 182 with 2-element "H" antennae attached to the wing struts (Dodge 1985). The date, time, location, and other comments were recorded with each contact. If a signal was slowed,-weak, or the signal had come from the same location for three consecutive contacts, hand-held antennas were used to locate and visually determine whether the bird was alive or dead. Locations were recorded and will be plotted using the UTM Coordinate system. Supplemental data, such as wind speed and direction, ambient temperature, and precipitation was recorded to be used as covariates in the survival and time budget analyses. Throughout the nesting period (May-July) birds were located as often as possible to monitor nesting chronology. If a duck was in the same location several consecutive times, indicating an incubating female, we attempted to find the nest site. If a nest was located, then weight, length, breadth and fertility of each egg and incubation stage was recorded. From this, an estimate of the nest initiation and probable hatching date could be made. Each nest of an instrumented female was marked with flagging. After the estimated hatching date, nest fate was checked. Nests of unmarked females were also measured in a similar manner, but no nest fate checks were made. Besides recording mortality of marked birds, we collected remains (usually just wings) from all waterfowl carcasses and attempted to determine the cause of death whenever possible. Most mallard wings were marked and frozen for later analysis. Additionally, a technique was developed to measure the lipid levels in carcass samples. First, a sample of 12 mallards were captured; some were killed immediately and others deprived of food for varying periods of time. These birds had the ulna excised, and were then subjected to whole body lipid extraction. The ulnas were cracked open and a seperate lipid extraction was performed on these bones. A relationship similar to that reported by Hutchinson and Owen (1984) was found between whole body lipids and ulna lipids. We were therefore able to assume that low levels of ulna lipid are indicative of starvation, but no quantitative measure of body condition can be made. Time Budget Time budget data were obtained using focal animal observations (Altmann 1974). Diurnal observations were made with a 40 power spotting scope, and nocturnal observations made with a light enhancing night vision scope. Birds was watched continuously for 10 minute intervals. Bird status (sex, marked or �72 not, and paired or not), habitat type, location, ambient conditions (temperature, wind speed,snowing or not, and location), date, and time observations started were recorded with the aid of a portable computer. Exact times of activity changes by the focal animal were entered on the portable microcomputer (Hensler et al. 1986). METHODS Yeight Changes - 1987-88 of Marked and Unmarked Mallards Mallards wintering on MVNWR were captured with Salt Plains bait trap$ (Szymczak and Corey 1976) and cannon nets (Dill and Thornberry 1950) during 4 trapping periods, from 11-18 January, 25 January-7 February, 8-22 February, and 29 February-4 March, 1988. Data on age, sex, weight, and wing length were obtained for all birds, and a condition index (Ringelman and Szymczak 1985) calculated for each. All mallards were banded with standard USFYS leg bands. During the 11-18 January trapping period, most mallards also had monel bands affixed to the shaft of primary feather VIII of both wings. Mean weights were plotted by trapping period and by week for each age-sex class. The UNIVARIATE Procedure (SAS Institute 1985) was used to test normality of weight and condition index distributions by age-sex class for each trapping period. Duncan's multiple range test was used to compare weight and condition index means by trapping period and age-sex class. To examine the relationship between weights and trapping method, weights of birds captured in cannon nets during the first trapping period were compared with weights of birds captured in bait traps during that same period. Yeights of birds recaptured within 7 days of initial capture were plotted as percent initial body weight for visual inspection. Linear regression was used to test for any relationship between duration of time between recapture and differences in initial and recapture weights and condition indices. Weight and condition indices of mallards originally banded in 1987 and recaptured in 1988 were examined to see if a bird in relatively "good" or "poor" condition in 1987 was in a similar relative condition class in 1988. Mean weight and condition index were placed in relative categories by subtracting mean weight and condition for the respective age-sex class from each respective trapping period. Instrumentation During the 11-18 January and 29 February-4 March trapping periods, adult females were assigned to 1 of 3 condition classes based upon their condition index relative to the distribution of the population in the SLV. Population distribution was determined by ordering the condition indices of adult females on the first trapping day. As in 1986-87, birds with a condition index in the upper 33% of the population (condition index >18.5) were considered to be in "good" condition, while those in the lower 33% (condition index <15.0) were considered to be in "poor" condition. A sample of 52 adult females in "good" condition and 51 in "poor" condition were radio-marked with 26 g transmitter packages attached with a back-pack harness (Dwyer 1972). Females in "average" condition were processed and released. , �73 High mortality of instrumented females during 1987 prompted us to anticipate high mortality again this season. Initially, we planned to reapply radios collected from dead females the week after the radio was collected. To reapply radios, we planned to trap weekly, then assign radios to adult females based upon their condition index and the cut-offs used during the 11-18 January trapping period. During this period, radio transmitters were reapplied to 23 adult females, 6 in "good" condition, 1 in "average" condition, and 16 in "poor" condition. Unfortunately, extremely high mortality of instrumented females, coupled with difficulties in trapping and changes in the condition of the population, made it impractical to reapply radios each week. Consequently, we decided in early February to reapply all remaining recovered radios during an intensive trapping effort 29 February-4 March. Procedures for the March trapping period were similar to those used in January. Condition index cut-offs were initially set at <12.5 for "poor" and >15.5 for "good" condition, but we were unable to trap a sufficient number of "poor" condition females. Therefore, later in the week, radios were also applied to females in "average" condition (12.5 to 15.5). Twenty-two females in "good" condition, 17 in "average condition, and 24 in "poor" condition were instrumented. Radio Tracking Radio tracking during 11 January through 26 March 1988 was conducted using both aerial search and ground crews. Procedures for both methods followed those used in 1986-87. When an instrumented birds was found dead, date, estimated date of death, likely cause of death, site description, UTM coordinates, and any other comments were recorded. Carcass remains found with the radio were collected and frozen for later analyses. From 27 March through 11 June, instrumented birds were visually located biweekly to determine nesting status. Nest parameters and estimated nest initiation date were measured as in 1987. Survival Rate Estimation The Kaplan-Meier method (Lee 1980) was used to estimate survival rates through 26 March of females in "good" and "poor" condition. Survival rate estimates were bracketed by plotting Kaplan-Meier estimates assuming censored birds had lived or died. Comparisons of weekly survival between condition classes were made using 2x2 chi-square tests. The square root of the weekly chi-square values were calculated to produce a z value, which was given a sign depending upon the difference in survival rates of "good" and "poor" condition classes. Pooled z values were used to test for an overall relationship between survival and body condition. Comparisons between condition class survival were made using the CATMon Procedure (SAS Institute 1982). Estimates of relative survival rates of wing banded birds in "good" and "poor" condition were made by a ratio of birds recovered divided by the number marked for each age-sex and condition class (Burnham et al. 1987:97). "Good" and "poor" condition were defined as the upper and lower third of the condition index distributions for the respective age-sex classes. Percentiles , �74 used to define "good" and "poor" condition were also changed to the upper and lower 25 percentiles and above and below the median to determine whether the percentile used to define condition classes affected inferences concerning any relationships between survival and condition class. Recovery rates of "good" and "poor" birds were tested with 2x2 chi-square tables by age-sex class, and for ages combined and overall. Wing band retention was checked on recaptured birds. Total mortality between 28 January and 4 February was estimated from differences in ducks counted from photos of roost areas taken at 154 m elevation. Collection of Instrumented Females At intervals of 2-3 and 4-5 weeks after the 11-17 January trapping period, 10 instrumented females (5 in "good" and 5 in "poor" condition) were collected for analyses on the effects of instrumentation on weight dynamics of free-living mallards. Similar collections were made 2-3 weeks after the March trapping effort. Birds were captured by hand-held nets, cannon nets, shotguns or rifles. Collected birds were immediately bagged and the following recorded: weight, wing length, condition index, blood smear sample, and any pertinent comments recorded before the carcass was frozen. Carcasses were later thawed and examined for signs of avian cholera. Wing and Carcass Collections Wintering waterfowl concentration areas and raptor perches on MVNWR were walked 5 days a week to collect remains of dead waterfowl. Species, age, sex, marsh unit where collected, and band numbers (if bands were present) were recorded. In addition, every fifth mallard wing was retained and frozen for later analysis of lipids in the ulna and Pasturella in the marrow of the radius. All wings found with wing bands were retained for the same analyses. A 4x13 chi-square table was used to test for a random distribution of mortality by age-sex class, using marsh units in which more than 5 wings were collected and for which the age and sex of carcass remains could be determined. Similarly, a 2xl3 chi-square table was used to test for a random distribution of recovered, banded-birds. Condition indices of wing-banded birds were analyzed for normality using the UNIVARIATE procedure (SAS Institute 1985), as were the condition indices of recovered wing-banded birds. Sample distributions were then compared to determine whether the distribution of recovered birds differed from the distribution of those marked. Wilcoxon rank sum tests were used to test for changes in the condition distribution of recovered birds compared with the condition distribution of birds banded. Wings retained for analyses were labeled and frozen in airtight bags. To expedite analysis, 100 ulnas were excised and cracked open at 1 end, then the exposed marrow was touched to a clean sheet of white paper to evaluate lipid content. The resulting blot was allowed to dry and then the paper was held up to a light source to evaluate the amount of residual lipid. A translucent blot indicated appreciable lipid ~esidue. If no visible blot remained, the ulna was presumed to have no lipids in it. To verify this technique, the 100 sample ulnas were cracked completely open, oven-dried, and lipids extracted for 6-8 hours using petroleum ether in a Soxhlet extraction apparatus. Blots were compared with extraction results to determine classification errors. A 2x2 chi-square table was used to determine if similar , �75 percentages of banded and unbanded birds appeared to have starved. The radius of each wing was cracked open and the marrow smeared on a clean microscope slide. The smears were then stained and examined for Pasturella. To determine the percentage of carcasses collected in areas searched, 25 carcasses with wing bands were placed around 3 water areas searched every 3 days by field technicians. Carcasses were placed in areas where carcasses had been previously recovered by technicians. Only the person planting the carcasses knew when and where they had been placed. Carcasses were checked 24 hours after placement to determine the initial rate of removal. Thereafter, carcasses collected by technicians were checked for wing bands of the planted carcasses, and wing band and marsh unit recorded. Fifteen carcasses were used to test whether Pasturella could be cultured from wing bones if the wing was not recovered immediately after death. One wing was removed form each carcass and placed in a wire cage to prevent scavengers from removing it, then exposed to the elements for 1 to 21 days. The carcass was frozen soon after the wing was removed. After the wing had been exposed for the required number of days, it was placed in the bag with the carcass from which it had been removed. Carcasses were later examined for gross lesions of cholera, and the liver cultured for Pasturella. Bone marrow from the radius of the exposed wing was cultured for Pasturella. Smears of the marrow were also made and stained to check for the presence of Pasturella. Standard Metabolic Rate Standard metabolic rates were measured using the open circuit oxygen consumption method. Captive adult mallards, which were held in a pen with indoor and outdoor access and subject to natural photoperiod, were supplied with food and water ad libitum. However, birds were denied access to food and water a minimum of 8 hours prior to taking measurements. Birds were placed in a darkened respirometer between 2000 and 0400 hrs and room air pumped through the chamber at the rate of 1.6 l/min. For analysis, air from the respirometer was.passed through columns of soda lime and drierite to remove CO2 and H20, resp.ectively. Oxygen content of the dried effluent air was measured with a Beckman F3 oxygen analyzer. Room air and a standard gas with 20.27% oxygen were used for calibration. All measurements were adjusted to standard temperature and pressure. Time Budget Diurnal time budget data were obtained from focal animal observations (Altmann 1974) made February through April 1988. Focal animals were initially selected by pointing a spotting scope at a mallard flock, then selecting a bird within the field of view. The bird's pair status and sex, as well as ambient temperature, wind speed, location, a~d habitat type, were recorded on a portable computer (Hensler et al. 1986). Ac~ivities were categorized as out of sight, rest, swim, walk, preen, dabble, tip~up, feeding on land, courtship, aggression, alert, fly, drink, bathe, and other. Percentage of time spent in the various activities was calculated and graphed. �76 Metebolizable Energy Ten captive adult mallards (5 males and 5 females) were fed the test food ~ libitum for a minimum of 21 days prior to testing to assure that gut morphology had adjusted to the diet (D. Johnson, pers. comm.). Birds were placed in isolation cages and trials were not started until all birds were eating and had returned to their approximate pre-trial weight. Prior to the 7-day trial, 8 meals were weighed to the nearest gram and divided into 2 portions, 1 to be fed in the morning and 1 at night. Meals exceeded ~ libitum intakes. Birds were weighed the day prior to trial initiation and again at trial completion. Ducks were denied access to food for 8 hours prior to starting the trial to allow food in the intestinal tract to be passed. Throughout the trial, birds were maintained at thermoneutrality. Dry weights of meals fed, dry weights of feces produced, and dry weights of food not eaten were recorded. Fecal samples from days 3-6 were combined to provide composite samples. After drying, composite grain and feces samples were frozen then later analyzed for gross energy with a bomb calorimeter. Nitrogen content was determined by the Kjeldahl method, then multiplied by 6.25 to give protein content. The difference between amounts of food fed and grain spilled was considered intake. Differences between intake and amount excreted was termed apparent digestible energy (Miller and Reinecke 1984). Raptor Counts Raptor predation was identified as an important mortality factor of mallards wintering on MVNWR in 1987. To monitor trends in the abundance of raptors utilizing MVNWR, a survey route was established which included most perches available on MVNWR. The route was driven weekly, from 14 January through 24 March 1988, in the early morning before human activity disturbed the birds. The route was not driven when visibility was less than 1.5 km. Raptors were classified by species, and bald eagles (Haliaeetus leucocephalus) further classified as either adult or immature. Trends in raptor populations were identified from a plot of the number of raptors observed from the route. Reproduction In addition to monitoring the instrumented birds through the nesting season, a survey route was established on MVNWR and driven weekly from 19 April through 15 June for the purpose of enumerating and the number of lone male and paired male mallards. Broods encountered were aged (Gollop and Marshall 1954), and from these data hatching dates were estimated. Weather Daily temperature maxima and mlnlma, and snow cover were obtained from National Oceanic and Atmospheric Administration reports (National Oceanic and Atmospheric Administration 1988a, 1988b, 1988c) for the Alamosa airport reporting station. Temperatures and snow on the ground from 1 January- 31 March were plotted to determine periods of weather change. , �77 RESULTS - 1986-87 One hundred and eighty-nine mallards were trapped, measured, and banded on the Monte Vista National Wildlife Refuge 17-20 December 1986. From 5-15 January 1987, 121 adult females, 354 adult males, 169 immature females, and 334 immature males were weighed and banded. More males and immature females were captured but not processed due to time limitations. All adult females captured were processed. For the 20-22 February trapping period 56 adult females, 165 adult males, 69 immature females, and 216 immature males were processed. Similar to the January trapping period, only a limited number adult and immature males, and immature females were processed. Condition Indices Mean condition indices for for all birds trapped were greater December than in January or February (Table 1). Female condition in Table 1. Mean monthly condition indices of mallards trapped in Salt Plains Bait Traps on the Monte Vista National Wildlife Refuge during winter, 1986-87. Month Mean Condition Adult Female Indices (Standard Deviation) Adult Male Immature Female Immature Male Dec 19.9 (4.4) 18.0 (3.6) 17.1 (4.6)' 16.5 (3.8) Jan 13.6 (4.7) 12.4 (3.9) 13.7 (4.0) 11.5 (4.2) Feb 14.8 (3.7) 10.4 (3.5) 13.3 (3.8) 9.7 (3.6) indices were higher than similar age class males (P<O.OOOI for both adults and immatures, ~-testt 895 df for adult comparison and 973 df for immature comparison). Adult males were in better condition than immature males (P<O.OOOl, ~-test, 1,348 df). Adult and immature female condition indices were similar (P-0.17, ~-test, 520 df). Condition indices for the four age-sex classes were greater for birds trapped in December than in January (P<O.OOOl for adult and immature males and adult females, P<0.0007 for immature females, ~-test, 429 df, 394 df, 137 df, and 197 df, respectively). Condition indices were not different between January and February females (P>0.05, ~-test, 134 df for adult and 236 df for immature). January trapped males had higher condition indices than February males (P<O.OOOl, ~-test, 516 df for adult and 506 df for immature). Recaptured individuals showed similar patterns of weight loss between the December-January and January-February trapping periods (Table 2). , �78 Table 2. Mean body mass changes of birds banded one trapping period and recaptured during the next trapping period. Month of Capture First Second Body Mass Age Sex n first ~apture Recapture ~ifference December Janauary A M 2 1162 973 -189 December January I F 4 922 841 -81 December January I M 4 1137 1024 -113 January February A F 4 955 928 -27 January February A M 24 1055 977 -78 January February I F 1 1014 862 -152 January February I M 22 1020 888 -132 Condition indices were approximately normally Shapiro-Wilk statistic) for all age-sex classes and periods with the exception of adult females trapped indices of adult females trapped in January differed n-l2l) due to kurtosis rather than skewness. distributed (P>0.05, the three main trapping in January. Condition from normal (P-0.026, Radio Tracking Most instrumented birds were contacted at least weekly (Table 3) until spring thaw began in mid-March. As ponds thawed throughout the SLV the birds became more dispersed and time-consuming to locate from the ground, so we became more dependant upon locating birds from the air and making ground checks to determine a bird's status. Flights from the Rio Grande River south to LaJara were generally most productive in terms of number of birds located (Table 4). No birds were located in the area bounded by highway 285 on the west, highway 17 on the east, 5 North Road on the South, and Highway 112 on the North. This highly agricultural area has little habitat other than irrigation ditches. �79 Table 3. Number of birds contacted by week from 18 January 1987 through 2 May 1987. Radio-tracking was not directed at finding as many birds as possible after 1 May since we attempted to determine the nesting stage of birds near MVNWR. Dates Number of Birds Contacted January Marking February Marking 18-24 Jan 69 25-31 Jan 38 1-7 Feb 42 8-14 Feb 59 15-21 Feb 10 22-28 Feb 20 32 1-7 Mar 22 11 8-14 Mar 29 25 15-21 Mar 31 24 22-28 Mar 7 5 29 Mar-4 Apr 28 21 5-11 Apr 19 23 12-18 Apr 18 17 . 19-25 Apr 17 15 5 7 26 Apr- 2 May �80 Table 4. Dates, locations, the 1986-87 field season.1 Date of Flight and numbers Locations of birds located from aircraft Flown during Number of Birds Located 2/6/87 Valley-wide 23 3/3/87 Russell Lakes South to LaJara 36 3/19/87 Rio Grande South to LaJara 13 3/26/87 MVNWR North to Russell Lakes 4/21/87 Valley-wide 29 5/7/87 MVNWR South to Antonito 19 5/11/87 Rio Grande South to LaJara 13 5/26/87 Rio Grande North to Saguache 6 6/4/87 Rio Grande Upstream to Creede 6 6/12/87 San Juans and MVNWR (all on MVNWR) 6/17/87 Rio Grande South to Antonito 7 6/18/87 Bueno Vista to Gunnison 4 6/19/87 Rio Grande North to Saguache 8 6/30/87 Rio Grande South to Antonito 11 9 18 Throughout the field season, only 1 bird was not contacted at least once after release. That bird was instrumented in February, had a condition index of 12.3, and was shot in October in northern New Mexico. Eight birds were not contacted in the Valley after mid-February, including 5 in "good" and 3 in "poor" condition. Twenty birds were not contacted after April. Four of these were instrumented in February (all in "good" condition). Birds instrumented in January which were not contacted after this t-ime included 8 in "good" and 9 in "poor" condition. Two birds which were subsequently located in the Gunnison Drainage were both in "good" condition and instrumented in January_ One was last contacted in the Valley on 27 February and the other was last contacted 20 ApriL , �81 Mortality Instrumented birds experienced high mortality. Twenty-eight of the females in "good" condition and 37 of those in "poor" condition when instrumented in January died during the period 17 January through 4 July, for minimal mortality rates of 0.538 and 0.699, respectively (Fig. 2). Mortality rates for females instrumented in February were 0.277 for females in "good" condition and 0.588 for females in "poor" condition. Two peaks in mortality for females instrumented in January occurred (Fig. 3). Causes of mortality during this period included eagle predation and starvation. Most mortality occurred on or around MVNWR (Figs. 4 and 5). Table 5. Daily survival rates for the period 18 January through 4 July 1987 obtained through MICROMORT for adult female mallards instrumented 5-15 January 1987 in the San Luis Valley. Condition Class Mean Daily Survival Rate Standard Error Good 0.99612 0.00008 Poor 0.99057 0.00011 Table 6. Daily survival rates obtained from MICROMORT of adult female mallards instrumented 5-15 January and 20-22 February 1987 in the San Luis Valley. Daily survival rates are calculated for the period 22 February to 4 July 1987. Condition Class Mean Daily Survival Rate Standard Error Jan Good 0.99761 0.00008 Jan Poor 0.99433 0.00016 Feb Good 0.99748 0.00011 Feb Poor 0.92308 0.00234 �82 State of Colorado Figure 1. Location of the San Luis Valley, Colorado. w > ::::; <[ I- 100 100 80 80 60 60 40 40 JAN HIGH 20 20 0 0 100 100 JAN LOW Z w a: w e, 0 80 ~ 80 60 I- 60 40 ~ 40 20 ~ 0 FEB HIGH 20 28 JUN 18 JAN 0 FEB LOW 18 JAN WEEKL Y INTERVAL Figure 2. Proportion of Instrumented by week, for the 1986-87 females potentially field season. alive, 28 JUN �83 ~ FEBRUARY HIGH [ ::}!:':j FEBRUARY LOW w D JANUARY HIGH > o __ JANUARY LOW 12 UJ a: w o W 8 a:: LL o a:: w m ~ => Z 4 o 18 JAN 28 JUN WEEK OF RECOVERY Figure 3. Mortality of Instrumented femal. mallards by week and condition class, 1986-87. �84 70,---------------------------------------------------~ Monte Vista ® + + Alamosa + + ® • • La Jar~ford ® @) 104-----~------r_----~----~------~----~----~----~ 115 125 105 '95 135 Figure~. Spatial distribution of recoveries for female mallards instrumented in January, 1987. Squares and pluses denote good and poor condition females, respectively. 70~--------------------------------------------------__, of: Monte Vista (!) 60 + AJamosa 50 + 40 @l. • 30 La Jara ® Sanford ® 20 Manassa @ 104-----~----~r-----~----,_----_r----_.----~r_--__, 125 115 95 105 135 Figure S. Spatial distribution of recoveries for female mallards instrumented in February, 1987. Squares and pluses denote good and poor condition females, respectively. , �85 Mea~ daily survival rates obtained from MICROMORT for the period of 18 January through 4 July 1987 were higher for birds in "good" than "poor" condition in January (Table 5). Females in "good" condition in either January or February did not survive at different rates (Table 6). Females in "poor" condition in January survived better than females in "poor" condition in February, yet poorer than females in "good" condition in either month (Table 6). Logistic regression of survival based upon month of banding or condition index, using the Statistical Analysis System (SAS) Categorical Modeling procedure (CATMOD), identified a significant affect of condition index on survival (P-O.0103). No month of marking or month-condition index interact"ion was found (P>O.5). As with mortality estimates based upon the instrumented birds, band recoveries suggest higher mortality of birds in "poor" condition at the time of banding (Table 7). Recoveries of nasal saddles also suggest this, but only 4 nasal saddles were recovered. (3 "0" and 1 "+"). Predation and scavenging made it extremely difficult to locate bands or nasal saddles. Table 7. Recoveries of banded birds based upon month of banding and condition. Number Month of Banding Condition Class Banded Recovered % December Good Poor 126 29 4 2 3.1 6.9 January Good Poor 346 462 5 13 1.4 3.8 February Good Poor 55 413 1 2 1.8 0.5 Reproduction Of the 31 birds which were known to be alive and in the" San Luis Valley in early May, only 2 females were found incubating. The first nest found was produced by a female instrumented 22 February in "good" condition (CI of 16.3). The nest was located in an alfalfa field about 200 m south of Highway 160 and 1 km west of Monte Vista. Her clutch consisted of 12 eggs with a mean egg mass of 50.4 g. The nest was found too early to determine fertility of the eggs. It was initiated about 20 May, and was predated in mid-incubation by an avian predator. The only other nest located was produced by a female with a condition index of 8.5 on 15 January. The nest was about 30 m up a talus slope north of the Rio Grande about 2 km downstream from South Fork. Her clutch consisted of �86 8 fertile eggs with a mean mass of 47.8 g. She initiated this clutch about 30 May, and was also unsuccessful in hatching any eggs. It appeared as if avian predators destroyed the nest just before hatching. Though many females remained on the MVNWR through the nesting period, no nest of instrumented birds were found. Four females appeared to be in the laying stage (in nesting cover at various times, generally early morning), but the nests must not have survived into incubation. Data was recorded for 18 nests of unmarked females. Eleven of these nests were located in cattails (~ latifolia), often over water, 2 were in flooded Baltic rush (Juncus balticus), 2 were in mixed Baltic rush and greasewood (Sarcobatus vermiculatus), and 2 were in dry Baltic rush. Mean clutch size of 10 incubated nests was 8.4. Mean egg mass of 6 clutches, containing 39 eggs known not to have been incubated was 48.4 g. Time Budget Time-budget observations were limited to only 27.5 hours of daylight and 2.3 hours of night observations. Females comprised about 40% of the total. Although most observations were planned for nasal-saddled birds, these marked birds were located too infrequently. Generally, birds alternated between foraging in the barley fields and resting on water areas. Night time observations revealed that the major activity was resting. The extensive amount of daylight hours spent foraging in the fields suggests that these birds have difficulties in obtaining enough energy for maintenance. RESULTS Weights Changes of Marked and Unmarked - 1987-88 Mallards Weight and condition indices were approximately normally distributed. Overall, adult males weighed more than immature males, which weighed more than aduit females, while immature females weighed the least (Duncan's Multiple Range test, 2679 df, P<O.Os). Adult females were in the best condition, followed by adult males, immature females, and immature males in the poorest condition (Duncan's Multiple Range test, 2679 df, P<O.Os). Mallards weighed more during the 10-18 January trapping period than the other trapping periods (Duncan's Multiple Range test, 2679 df, P<O.Os). Birds were in better condition during the first trapping period, followed by the second period, then the fourth period, with the poorest condition indices recorded during the third trapping period (Duncan's Multiple Range test, 2679 df, P<O.Os). Adult males weighed more than immature males, which weighed more than adult females during each trapping period (Table 8). During the 25 January-7 February trapping period, adult and immature females were similar in weight, otherwise adult females weighed more (Table 8). Generally, adults were in better condition then immatures and females in better condition than males (Table 9). �87 Table 8. Mean and standard error for weights ~f mallards captured in the San Luis Valley. Letters a-d indicate significant differences among means (P-0.05) within an age-sex class. Letters w-z compare among age-sex classes within a trapping period. Trapping Period Adult Immature Male Female 10-18 Jan 1l01(±98)aw n-783 963(±76)ay n-274 1029(±85)ax n-495 915(±79)az n-390 25 Jan7 Feb 1032(±74)bw n-34 898(±80)bcy n-43 953(±97)bx n-16 889(±70)aby n-45 8-22 Feb 1002(±65)bw n-46 889(±47)cy n-18 940(±49)bx 827(±78)cz n-22 1019(±76)bw n-152 927(±70)by n-9l 946 (±71)bx n-144 23 Feb4 Mar Female Male n=Ll, 871 (±80)bz n-122 Table 9. Means and standard errors for condition indices of mallards captured in the San Luis Valley, Colorado, during 4 trapping periods in January-March 1988. Letters a-d indicate significant differences among means (P-0.05) within an age-sex class. Letters w-z compare among age-sex classes within a trapping period. Trapping Period - Adult Male Immature Female Male Female 10-~8 Jan l5.4(±4.0)aw l5.9(±4.4)aw l3.9(±3.8)ay l4.8(±4.3)ax 25 Jan7 Feb l3.3(±3.4)bw l3.0(±5.2)bcw 10.6(±4.6)bx l4.0(±3.3)abw 8-22 Feb 10.9(±3.0)cw l2.l(±3.l)cw 23 Feb4 Mar l2.l(±3.5)bcx l4.6(±4.0)abw 9.7(±2.9)bw 9.7(±4.9)cw 10.0(±3.8)by l2.6(±4.5)bx Two hundred and twenty-one mallards wer~ captured with cannon nets and 1,426 captured in bait traps during the first trapping period. Mallards captured in cannon nets weighed more than birds captured in bait traps (Duncan Multiple Range Test, 1,639 df, P<0.05, Table 10). Analysis of variance indicated significant trap method (F-14.55, P-O.OOOl, 1 df), age (F-59.52, P-O.OOOl, 1 df), sex (F-8.56, P-0.0035, 1 df), and age-sex interaction (F-322.42, P-O.OOOl, 1 df) effects. Age-trap, sex-trap, and age-sex-trap interactions were not significant. , �88 Table 10. Mean weights Luis Valley, Colorado, (SE) of mallards captured 11-18 January 1988 in the San in cannon nets and Salt Plains bait traps. Trap Method Male Female Male Female Cannon 1128(86) 970(72) 1045(78) 952(73) n-88 n-63 n-38 n-32 1090(101) 961(79) 1026(85) 913(78) n-537 n-191 n-380 n-318 Net Bait Trap Adult Immature Mallards banded and recaptured during the 1988 season had lower weights and condition indices at recapture than at the initial capture (F-16.957, P<O.OOOl, 205 df and F-5.833, P-0.0166, 205 df, for weight and condition indices, respectively). Although mean weights of unmarked birds declined with time, recaptured immatures weighed consistently less than unmarked birds (Figs. 6 and 7). Adult male recaptures were similar to unmarked birds (Fig. 8). Too few banded adult females were recaptured to make any comparisons with unmarked birds captured (Fig. 9). Generally, mean weights of birds recaptured within 7 days of initial marking weighed less than at initial capture (Figs. 10 and 11). Weight and condition indices were not different between initial capture and recapture (F-3.026, 115 df, P-0.0846, 115 df and F~0.9l7, 115 df, P-0.3402, for weight and condition index, respectively). One hundred and twenty mallards banded in 1986-S7 and recaptured during 1988 were used in analyses of relative condition be~ween years. Only 4 females classified as adults in 1986-87 were recaptured in 1988, and no relationship between condition in 1986-87 and 1988 was detectable (F-O.OOO, P>O.9892, 3 df). A positive relationship (Fig. 12) was detected for 1986-87 adult males (F-8.934, P<0.0044, 49 df) and 1986-87 immature males (r-18.320, P<0.0002, 30 df, Fig. 13) Immature females captured in 1986-87 and recaptured in 1988 did not show a relationship (Fig. 14) between relative condition in 1986-87 and 1988 (F-l.587, P<0.2634, 6 df). Survival Rate Estimation Kaplan-Meier 10 week survival estimates for females instrumented in January and 3 week estimates for females instrumented March are given in Table 11. Cumulative survival rate estimates for January-marked females were not changed much when censored birds were assumed to ha~ lived (Fig. 15) or died (Fig. 16), because most birds were contacted weekly (Appendix B). Most instrumented females died within 3 weeks of release (Fig. 17). �_._ UNMARKED - .- RECAPTURE 1200 1150 " OJ •... ~ :x: 1100 (144) 1050 CJ iii (11) 1000 ~ >- 150 Q 0 --- --- --- --- ---- .----- --- •. • 00 CD 850 (21) ( 1) 800 750 700 10-18.1AN 25.1AN-7 FEB 8-22 FEB 23 FEB-4 MAR TRAPPING PERIOD Figure 6. Mean weights of Immature male mallards trapped In the San Luis Valley, Colorado, during 4 trapping periods In 1988. Sample sizes are shown In parentheses. _._ UNMARKED -.- RECAPTURE 1200 1150 "om ...... ',00 ~ 1050 :x: CJ iii 1000 (45) (122) ~ >- .50 0 CD .00 Q 850 ... 800 _---- ------- 750 ( 10) (3) 700 10-18 .IAN U.lAN-7 FEB 8-22 FEB 23 FEB-4MAR TRAPPING PERIOD Figure 7. Mean weights of Immature female mallards trapped In the San Luis Valley, Colorado, during 4 trapping periods In 1988. Sample sizes are shown In parentheses. , �90 _._ (783) UNMARKED 1200 - • •.... 1150 ~ 1100 ~ 1050 - RECAPTURE (4.) (152) CJ iii ~ 1000 >- .50 o .00 C (30) (5) ID ISO 100 760 700 10-18 JAN 26 JAN-7 FEB '-22 23 FEB-4MAR FEB TRAPPING PERIOD Figure 8. Mean weights of adult male mallards trapped In the San Luis Valley, Colorado, during 4 trapping periods In 1988. Sample sizes are shown In parentheses. _._ UNMARKED 1200 •.... Cl 1150 •... 1100 ••• x: 1050 iii 1000 - • - RECAPTURE (11) CJ ~ >- 150 0 .00 C ". ID 860 800 ( 1) 760 -- . (5) 700 10-18 JAN 26JAN-7 FEB 8-22 FEB TRAPPING PERIOD Figure 9. Mean weights of adult female mallards trapped In the San Luis Valley, Colorado, during 4 trapping periods In 1988. Sample sizes are shown In parentheses. UFEB-4MAR �91 ~ ::z:: CJ iii 110 ~ 105 r- • aDULT o IMMATURE ~ > o o (23) (24) m (33) ..J oct Z 100 (5) I a:o (12) ~ Z au a:: au (I) ~ s o . (1.) .0 ~ (4) D. I 85 , J I 2 5 DA YS BETWEEN RECAPTURE Figure 10. Weights (as % of Initial capture weight) of adult and Immature male mallards recaptured within 7 days of Initial capture In the San Luis Valley, Colorado, January-March 1988. Sample sizes are shown In parentheses. ~ ::z:: CJ iii 110 ~ aDULT D. IMMATURE ~ > 0 0 105 m ..J oct Z 100 (3) (3) (; a:0 f .5 ~ Z au 0 a:: au (4) .0 I (4) D. 85 1 2 3 DA YS BETWEEN " RECAPTURE Figure 11. Weights (as % of Initial capture weight) of adult and Immature female mallards recaptured within 7 days of Initial capture In the San Luis Valley, Colorado, January-March 1988. Sample sizes are shown In parentheses. 5 �92 18 CO CO 0) •.. I ~ Z • 0 t= 3 is z 0 ,·O.~O 18CONDITION.O.~'O(17CONDITION)-O. 710 12 0 o W > t= « ...I W -3 -. -I c:t -12 -. -15 -15 -12 -I -3 0 3 1 I 12 15 I 12 115 RELATIVE CONDITION IN 1986-87 Figure 1 2. Relative condition 1986-87 and recaptured Indices of adult males captured In In 1988 In the San Luis Valley, Colorado. 15 88CONDITION.0.'U(B7CONDITION)-0.813 co co ,·0.12 12 I 0) <pO ~ I Z 0 3 is z 0 t= 0 o W > t= « ...I W c:t -3 . -I - -12 -15 -15 -I -12 -. -3 o 3 • RELATIVE CONDITION IN 1986-87 Figure 13. Relative condition 1986-87 and recaptured Indices of Immature males captured In In 1988 In the San Luis Valley, Colorado. , �93 18CONDITION-0.3.0(17CONDITION)+0.3.. 12 CO CO en .•.. i: z 0 ,-0 •• ' • • • 3 ~ 0 Z 0 (J W > ~ _, oCt w a:: 0 -3 • -. -. -12 -. -15 -15 -12 -I o -3 3 I • 12 RELATIVE CONDITION IN 1986-87 Figure 14. Relative condition Indices of Immature females captured in 1986-87 and recaptured in 19881n the San Luis Valley, Colorado. ~ -GOOD· CONDITION 0.' _, > sa:: - -. 0.8 -. ·POOR" CONDITION oCt =» w 0.7 0.1 (h > ~ 0.5 oCt _, 0.• =» ~ =» (J 0.3 0.2 0.1 0 0 WEEK Figure 15. Cumulative females Instrumented weekly survival rates and standard errors of In January, assuming censored birds survived. , �94 -e- ·GOOD" CONDITION - -. ·POOR" CONDITION 0.' _, 0.8 - ~ > 5= 0.7 :;) 0.' a: (/) IU > i= 0.5 :E :;) 0.3 _,:;)~ o 0.• 0.2 0.1 0 0 WEEK Figure 16. Cumulative females Instrumented weekly survival rates and standard In January, assuming censored errors of birds died. 25 (/) 0 a: iii 20 0 ~ IU 0 u, 15 0 a: IU CD 10 Z 5 :E :;) 0 WEEKS AFTER INSTRUMENTATION Figure 1 7. Number of weeks between Instrumentation and recovery 97 Instrumented female mallards found dead In the San Luis Valley, Colorado, In 1988. of , �95 Table 11. Weekly Kaplan-Meier survival estimates and standard errors for adult female mallards instrumented in the San Luis Valley, Colorado, 1988. March Marking "Poor" "Good" Week January Marking "Good" "Poor" 13-20 Jan 0.867(0.047) 0.727(0.057) 21-27 Jan 0.676(0.062) 0.875(0.068) 28Jan-3Feb 0.806(0.062) 0.875(0.059) 4-10 Feb 0.885(0.063) 0.800(0.056) 11-17 Feb 0.864(0.061) 0.926(0.061) 18-24 Feb 1. 000(0.066) 0.846(0.055) 25 Feb-2 Mar 1. 000(0.066) 0.905(0.057) 3-9 Mar 1. 000(0.066) 0.947(0.057) 0.833(0.070) 0.857(0.071) 10-16 Mar 0.947(0.064) 0.944(0.056) 0.923(0.096) 0.941(0.086) 17-23 Mar 1.000 (0.064 ) 1.000(0.058) 0.909(0.113) 0.875(0.107) In only one week did survival rates differ by condition class; from 20-27 January significantly more "good" condition females died (X2-S.l3, 1 df, P~0.023s). During the other weeks, as well as the pooled chi square, no significant differences in survival were detected between birds in "good" and "poor" condition. Similarly, CATMOD (P-0.2143) and the z-test (z-0.737) failed to detect a difference in survival between the two groups. Since no differences were detected between survival rates of the 2 condition classes, estimates were pooled (Table 12, Fig. 18). Relative survival ratios (Table 13) were not different from 1:1 overall, by age, or for any age-sex class of wing banded birds (Table 14). When the cut-off values defining "good" and "poor" condition are changed to above or below the median and the upper and lower 25 percentiles, only immature females show differences in the number of recoveries of birds in "good" and "poor" condition (Table 15). More immature females in "poor" condition were recovered using both definitions (Table 15). As with instrumented females, most wing bands were collected within three weeks after release (Figs. 19-22). Wing band loss probably did not differ according to condition class, but age did effect band loss. Of 65 wing-banded birds recaptured and checked, 18% of the birds had lost 1 wing band, but none of the recaptured birds had lost both wing bands. Of the 24 birds for which age and sex were recorded, 6 had lost I wing band. All 6 birds were immatures, 3 males and 3 females. Ten adult males, 6 immature males, and 2 immature females had retained both bands. No adult females were checked. �96 0.' ..J - 0.11 ~ ,.OOLED SURVIVAL ct > 0.7 ~ 0.' > i= 0.11 ::E ~ 0.3 sa::: en w ct ..J ~ 0 0.4 0.2 0.1 0 0 WEEK Figure 18. Cumulative weekly survival rates and standard errors of pooled survival estimates. 20 0 15 W t- o W ..J ..J 0 0 10 ~ ·POOR" CONDITION ~ ·AVERAGE· •• CONDITION ·GOOD" CONDITION a::: w m ::E ~ Z II o 7 • • WEEK OF COLLECTION Figure 19. Number of weeks between release and recovery banded adult female mallards In the San Luis Valley, Colorado, of wlng- 10 11 �97 20 ~ 0 III t'8Z8 11 •• t0 III ..I ..I 0 0 10 ·POOR" CONDITION ·AVERAGE" -GOOD· CONDITION CONDITION a: III CD ~ ::l Z I o WEEK OF COLLECTION Figure 20. Number of weeks between release and recovery of wlng- banded adult male mallards In the San Luis Valley, Colorado, 1188. 20 l?Z3 0 15 ~ III •• t0 W ..I ..I 0 0 10 ·POOR" CONDITION ·AVERAGE" "GOOD" CONDITION CONDITION a: w CD ~ ::l Z I o WEEK OF COLLECTION Figure 2 1. Number of weeks between release and recovery of wlng- banded Immature female mallards In the San Luis Valley, Colorado, 1188. , �98 20 PZa 0 •• W t- 0 _,_, W 0 0 10 CONDITION ·AVERAGE"' ~ 111 ·POOR- ·GOOD- CONDITION CONDITION a:: w m ~ :l Z I o WEEK OF COLLECTION Figure 22. Number of weeks between release and recovery of wlngbanded Immature male mallards In the San Luis Valley, Colorado, 1888. 1200 ____ -Good" 1100 t- X 1000 c" (2) iii ~ .00 g aoo >o ------ ~ (3) 700 .00 o 7 14 21 28 35 DAYS BETWEENINSTRUMENTATION AND COLLECTION Figure 23. Mean body weight and standard error for females collected less than 14 days, 15-28, and 30-33 days after Instrumentation. Also given are mean body weights at capture for the collected birds. Sample sizes are shown In parentheses. , �99 Table 12. Pooled weekly Kaplan-Meier survival estimates and standard errors for adult female mallards instrumented in the San Luis Valley, Colorado, 1988. Week January Marking March Marking 13-20 Jan 0.797(0.037) 21-27 Jan 0.776(0.046) 28 Jan-3 Feb 0.841(0.043) 4-10 Feb 0.843(0.042) 11-17 Feb 0.895(0.043) 18-24 Feb 0.923(0.043) 25 Feb-2 Mar 0.953(0.044) 3-9 Mar 0.974(0.044) 0.845(0.050) 10-16 Mar 0.946(0.043) 0.932(0.064) 17-23 Mar l.000(0.043) 0.892(0.078) Table 13. Relative survival ratio, by age and sex, of mallards wintering the San Luis Valley, Colorado, and marked with monel wing bands. Condition Class Number Banded Number Recovered Survival Ratio SE Age Sex Adult Male Good Poor 251 246 21 22 l.069 0.312 Female Good Poor 82 80 6 l.879 0.907 11 Pooled Good Poor 333 326 27 33 l.248 0.309 Male Good Poor 169 165 13 20 l.576 0.534 Female Good Poor III 12 18 l.586 0.550 105 Good Poor 280 270 25 38 l.576 0.383 Good Poor 613 596 52 71 1.404 0.243 Immature Pooled Overall in , �100 Table 14. Comparisons of recoveries of wing-banded birds in the upper and lower thirds of the condition index distribution at the time of banding. Number of recoveries are given in Table 7. X2 Value Comparison df P Power of Test Adult Male 0.0439 1 0.8340 0.056 Adult Female 1.4454 1 0.2293 0.264 Immature Male 1. 5083 1 0.2194 0.271 Immature 1. 3667 1 0.2424 0.267 0.6730 1 0.4120 0.147 2.8497 1 0.0914 0.475 3.1710 1 0.0750 0.508 Adult, Female Pooled Immature, Pooled Overall Table 15. Comparisons of recoveries of wing-banded birds using different portions of the condition index distribution to define "good" and "poor" condition. All tests are Chi-Square tests with 1 df. Power refers to the power of the statistical test. Above/Below P X2 Comparison Median Power Upper And Lower 25% X2 P Power Adult Male 0.389 0.532 0.11 0.199 0.656 0.08 Adult Female 2.688 0.101 0.45 0.820 0.365 0.17 Immature Male 0.003 0.959 0.05 0.057 0.811 0.06 Immature 4.953 0.026 0.74 5.656 0.017 0.82 Female Adult, Pooled 0.097 0.756 0.06 0.014 0.907 0.05 Adult, Immature 2.884 0.090 0.48 2.843 0.092 0.48 1.952 0.162 0.34 1. 722 0.189 0.31 Overall �101 The 28 January duck count from aerial photographs was 23,570, with possibly 590 more birds present but untallied. The 4 February count was 20,864 with up to 1,475 more ducks untallied. These counts produce a 7-day survival rate estimate of 0.885 (or 0.925 in the additional untallied ducks are included). The corresponding survival rate of instrumented females was 0.841 (±0.043). These rates are similar (z-1.023). Assuming a rate of 0.90 (or 0.985/day) based on aerial counts, under a regime of constant mortality, this corresponds to a 70-day survival rate of 0.349. This rate is bracketed by the 0.3-0.4 70-day survival rate experienced by instrumented females (Figs. 15 and 16). Collection of Instrumented Females Eight instrumented females in the "good" condition class and 7 in the "poor" condition class were collected during the first period. During the second period, 5 females of each condition class were collected. During the third period, 3 "good", 4 "average", and 3 "poor" condition females were collected. Mean weights of all birds collected up to 33 days after instrumentation declined (Fig. 23, Table 16). None of these birds exhibited gross lesions typical of fowl cholera. During the first period, females collected an average of 15.0 (±2.2) days after instrumentation lost a mean of 238 g (range 59 g to -410 g). Condition indices declined an average of 15.4 (range 4.4 to -27.8). Weight and condition of collected females did not differ according to condition class (Table 17). Females of the two condition classes showed similar weight losses and declines in condition indices (Table 17). Table 16. Mean and standard error at time of collection for weight, condition index, and weight and condition index changes of instrumented female mallards collected 2-3 and 4-5 weeks after instrumentation. Collection Period Condition Class 1 "Good" 752(117) 2.3(8.0) -298(86) -18.9(6.8) "Poor" 720(115) 1.8(6.8) -170(106) -11.5(7.2) "Good" 920(63) 13.1(3.3) -151(27) - 8.3(2.1) "Poor" 799(30) 6.1(1.5) -112(23) - 7.4(1.3) "Good" 805(31) 7.0(2.3) -186(35) -12.0(2.3) "Average" 784(29) 5.4(3.3) -152(30) -10.2(2.6) "Poor" 817(59) 7.6(4.0) - 54(31) - 3.20.7) 2 3 Body Weight Condition Index Weight Change Condition Change �102 Table 17. Comparisons of weights and condition indices at collection and weight and condition index changes for adult female mallards instrumented in "good" and "poor" condition 11-18 January 1988 and collected 2-3 and 4-5 weeks after instrumentation. Collection Period 2-3 weeks 4-5 weeks Comparison ~ value df P Weight 0.53 13 0.6069 Condition 0.11 13 0.9154 Weight Change -2.05 13 0.0611 Condition -1.61 13 0.1323 Weight 3.81 8 0.0052 Condition 4.31 8 0.0026 Weight Change -2.16 8 0.0632 Condition -0.74 8 0.4799 Change Change During the second period, females were collected 28.3 (±2.6) days after instrumentation and lost an average of 132 g (range -71 g to -177 g) and condition indices declined an average 10.1 (range -4.4 to -10.1) in the 4-5 weeks. "Good" condition females weighed more (Table 11) and were in better con~ition (Table 17) at the time of collection than "poor" condition females. Weight declines were similar between the two groups, as were declines in condition (Table 17). Females instrumented in March were collected 18.1 (±4.5) days after instrumentation and had lost an average of 133 g (range -32 g to -209 g). Condition indices declined 8.6 (range -1.4 to -14.4). Weight and condition changes differed between "good" and "poor" condition females and between "average" and "poor" condition females (Table 18). During the first period only 1 banded adult female was recaptured. She weighed 888 g and had a condition index of 13.4. Unmarked adult females captured during this period weighed more than the collected birds (~--6.45, 51 df, P-0.0001) and were in better condition (1--6.51, 51 df, P-0.0001). The only banded adult female recaptured during the second collection period weighed 795 g and had a condition inde~ of 3.4. Four unmarked adult females were captured during this period. Neither their mean weight of 805 g nor their condition was different from the mean weight or condition of the collected birds (1-0.96, 12 df, P-0.3574 and 1-0.78, 12 df, P-0.449l, respectively). �103 Table 18. Comparisons of weights and condition indices at collection and weight and condition index changes for adult female mallards instrumented in "good", "average" and "poor" condition 29 February-4 March 1988 and collected 2-3 weeks after instrumentation. Condition Classes Compared Comparison "Good" and "Poor" Weight and "Poor" P 4 0.7702 -0.24 4 0.8230 Weight Change -4.87 4 0.0082 Condition -4.35 4 0.0122 -0.91 5 0.4028 -0.73 5 0.5001 Weight Change 1. 38 5 0.2257 Condition 0.81 5 0.4541 -0.98 5 0.3708 -0.83 5 0.4455 Weight Change -4.18 5 0.0087 Condition -3.47 5 0.0179 Index Change Weight Condition "Average" df -0.31 Condition "Good" and "Average" .! value Index Change Weight Condition Index Change Wing and Carcass Collections An outbreak of avian cholera began on MVNWR in early December 1987, and prompted closure of the refuge to waterfowl hunting before the scheduled season closure. Between 4 January and 1 April 1988, we collected 4,604 remains, of which 4,193 were mallards. Other carcasses collected were primarily Canada geese (Branta canadensis) and northern pintails (Anas ~). Throughout January and early February more than 400 carcasses per week were collected (Fig. 24). Although the number of carcasses collected per week declined through late February and early March, this was more a function of reduced search effort (Fig. 25) than reduced mortality rates. Even though cholera was the suspected cause of death for most birds, some waterfowl apparently died from lead poisoning, starvation, predation, and collisions with wires. The distribution of mallard wings by age-sex class was evaluated using 1,641 wings. More males were collected in unit 7, immature males in units 14 and 20, adult males in unit 18, and adult females in unit 21 than expected �104 700 .00 800 (I) C a:: iii c oct 400 300 W C 200 100 0 WEEK Figure 24. Number of dead waterfowl collected weekly between January and March 1988 on the MVNWR. 18 .•.... a:: 18 •.... • 14 0 12 J: <, ~ -a:: u.. u, W ~ Z :l 10 I <, (I) C a:: iii c I 4 oct W C 2 WEEK Figure 25. Number of dead waterfowl collected per hour of search time, January through March 1988, on the MVNWR. �105 (P-O.OOOl, Chi-square-75.37l3, 36 df). Fewer immature males were collected in units 16 and 23, immature females in unit 1, and adult females in unit 18. More banded birds were collected in units 16 and 23 than were expected (P-0.0397, Chi-square-21.8l23, 12 df). Condition indices of wing banded birds were normally distributed for all age-sex classes except adult females (P>0.5 for all age-sex classes except adult females, W-0.964, P-O.OOl, for adult females, Figs. 22-25). Adult females were negatively skewed and kurtotic. Condition indices of recovered immature females and adult males were normally distributed (W-0.968, P-0.299 and W-O.965, P-O.119, for immature females and adult males, respectively, Figs. 26 and 27). Condition indices of recovered adult females and immature males were negatively skewed and kurtotic (W-0.894, P-0.008 and W-O.936, P-0.028, for adult females and immature males, respectively, Figs. 28 and 29). Wilcoxon sign rank test detected differences in the distribution of condition indices of recovered birds compared with the distribution of banded birds for adult males (z-2.25, P-O.0244). Other age-sex classes did not show any differences (z--0.37, P-0.7086; z--O.16, P-0.87l5; z-0.99, P-0.3242 for adult females, immature females and immature males, respectively). Of the 100 wings from which lipids were extracted from the ulna, 8 were from birds that appeared to have starved. No classification errors occurred when fat blots were compared with extraction results. Because no classification errors were apparent, the remaining wings were only sampled with the blot technique. Of the 900 wings sampled, 60 (6.7%) appeared to have been from birds that had starved. Bone marrow smears from the radius bones have been made, but not yet examined. Twenty-nine of 201 banded birds (14.4%) found dead and analyzed for relative ulna lipid levels appeared to have starved. This is a significantly greater percentage than for unmarked birds analyzed (31 of 699, 4.4%; P-O.OOOO, Chi-square-20.87l9, 1 df). Ulna lipids were extracted from the wings of 52 dead, instrumented females. Twelve (23%) appeared to have come from birds that had starved. Of the 25 planted carcasses, 17 (68%) were eventually recovered. Carcasses were recovered an average of 6 days (SE-4) after placement. Only 1 carcass was recovered in a marsh unit other than where it was placed; that carcass was planted in unit 15 and recovered in unit 22. Five carcasses were taken by scavengers from the area they were placed in within 24 hours, and only 1 was later recovered. Of 24 carcasses necropsied, 17 had positive liver cultures for cholera and 7 were negative. Of the 17 that tested positive, 16 (94%) showed gross lesions characteristic of cholera, 13 (76%) had positive bone marrow cultures, and 12 (71%) showed positive marrow smears. None of the carcasses with negative liver cultures were positive for any of the other tests. Determination of detectability of cholera in wings which had been exposed to the elements for varying periods of time have not been completed yet. Standard Metabolic Rate Only 11 usable SMR measurements were obtained out of the expected range (Fig. 30). Lower critical determined from these measurements. and several temperature of these are can not be �106 eo o &IJ a: CJ ALL BIRDS ~ RECOVERED BIRDS 35 &IJ ~ 30 o &IJ U &IJ m 20 ~ 15 a: a: Z 10 5 o o 5 10 15 20 25 CONDITION CLASS Figure 26. Condition Indices of Immature females banded 11-18 January 1988 on MVNWR and condition Indices of banded Immature females found dead January-March 1988 on MVNWR. eo 75 ~ 70 ~ ~ ~ ~ ~ g- 85 0 &IJ 10 a: 55 > 0 0 41 &IJ a: a: 40 m 30 :l 215 &IJ &IJ ::; Z 10 315 20 15 10 5 0 [ CJ ~ ALL BIRDS RECOVERED BIRDS ~ ~ ~ g!;g~ ~ ~ !; g- nn.. o n n r1n 5 a ~ ~ ~ [51 ~ ~ ~ ~ ~ 10 CONDITION CLASS Figure 27. Condition Indices of adult males banded 11-18 January on MVNWR and condition Indices of banded adult males found dead January-March 1988 on MVNWR. bt A 20 ~ ~n n _n 215 �107 40 35 0 W 30 CJ ~ ALLIIRDS "ECOVERED IIRDS a:: W > 0 25 0 W a:: a:: 20 w m 15 Z 10 :E ::l 5 0 CONDITION CLASS Figure 28. Condition Indices of adult females banded 11-18 January 1988 on MVNWR and condition females found dead January-March Indices of banded adult 1988 on MVNWR. 10 55 0 50 a:: 45 > 0 40 0 IU 35 W c=J ~ ALL BIRDS RECOVERED BIRDS IU a:: a:: 30 w u :E ::l 20 m Z 15 10 5 0 25 CONDITION CLASS Figure 29. Condition Indices of Immature males banded 11-18 January 1988 on MVNWR and condition Indices of banded Immature males found dead January-March 1988 on MVNWR. , �108 225 I- 200 I- 175 I- 150 I- 125 I- 100 I- >- • • ••• • ~ 0 <, .J ~ 0 ~ 711 I- 110 I- 25 I- 0 -30 • • • •• I I I I I I I -20 -10 o 10 20 30 "'0 AMBIENT TEMPERATURE Figure 30. Standard metabolic rate measurements mallards made In the San Luis Valley, Colorado. of captive, adult �109 Time Budget From 18 February through 1 April 1988, 4.27 hours of focal animal time budget data were obtained. All observations were of birds around open water and environmental conditions were very similar. Swimming, feeding, and resting accounted for 73.4% of the observation time (Fig. 31). Metabolizable Energy Two grains grown in the SLV were measured for metabolizable energy, steptoe barley and field peas. Gross energy of steptoe barley was 18.85 (±0.24) kj/g and field peas was 18.37 (±O.05). Overall, birds maintained on field peas lost an average of 19.3 (± 19.8) g while those maintained on steptoe barley gained 13.2 (± 21.6) g. Apparent metabolizable energy was similar for the 2 foods (Table 19, ~-O.26, 18 df, P-0.7977). Intake energy did not differ between the 2 foods (Table 19, ~--1.86, 18 df, P-O.0791), but fecal energy of barley was greater than for peas (Table 10, ~--2.29, 18 df, P-0.0345). Daily protein intake was 7.31 (±1.58)g and 2.14 (±1.50)g was retained for birds fed steptoe barley. Analysis of the field pea and fecal samples from birds fed field peas have not been completed yet. Table 19. Daily intake, fecal, and apparent metabolizable energy (in Kj/day) of field peas and steptoe barley grown in the San Luis Valley, Colorado and fed to adult mallard ducks. Food Intake energy Fecal Energy Apparent Metabolizable Energy Peas 787.9(232.8) 193.6(67.0) 13.91(0.42) Barley 984.0(213.6) 258.2(51.9) 13.85(0.56) Raptor Counts Raptor populations peaked on MVNWR during the week of 31 January-6 February when 98 raptors were observed (Fig. 32). Total raptor populations were primarily influenced by eagle numbers (Fig. 32 and 33). Adult bald eagles outnumbered immatures on all counts, although some of the unidentified eagles were probably immature bald eagles which could not be definitively separated from golden eagles (Aguila chrysaetos). Reproduction Two instrumented females were found associated with nests. One female, instrumented 11-17 January with a condition index of 14.0, nested in baltic �110 -es observations, behavior A •• t ~ Maintenance Courtahlp other of 4.7 hours of focal animal time budget made In February categories. 'eed ~ t7J lZI Figure 31. Proportion Swim and March 1988, spent In different Male and female observations are combined. 100 10 eo Q W 70 W eo ->a: en al 0 en a: 0 ~ 50 "0 Q. < a: 30 20 10 0 1/14 1120 1128 2/" 2/11 2/11- 2/25 3/3 3/10 3/18 3/24 DA TE OF COUNT Figure 32. Total raptors counted MVNWR, January-March 1988. from a roadside census route on , �111 __._ TOTAL EAGLES --b - ADULT aALD •••• .•• IMMATURE 3/10 3/18 70 c w > a: w en CO 0 .0 eo CO en w ..J 30 CJ < w aALD &._--- 20 .& , ,, ,,' • ' ..... A •........•.. ......•.. 10 ,, ,, , .........•....... \,- ~-- \ , \ . .' .... /k-- •........••• ' .....<:'~ .... .. ..... 0 1I1~ 1/20 1128 2/~ 2/11 2/1. 2/25 3/3 3/24 DATE OF COUNT Figure 33. Number of adult, Immature, and total eagles counted from a roadside census route on MVNWR, January-March 1988. 220 LONE MALE 200 180 c w 180 Z 1~0 o o 120 w 100 ~ ;:) en ...J < ~ 80 80 ~o 20 o ~/1' C/28 1/17 • 1/2~ ./3 . DATE OF COUNT Figure 34. Number of male mallards counted from a census route on MVNWR and classified as lone or paired from mid-April through mid-June 1988. ./8 ./15 �112 rush south of the Avocet Trail in unit 20. She had 4 eggs and very little down when the nest was located. This nest was destroyed by avian predators. The second female was instrumented in late January ana had condition index of 8.6. Her nest was located in early June in cattail in unit 18. It had 7 eggs surrounded by abundant. The fate of this nest is unknown because it could not be located for a follow-up check. The ratio of lone:paired males increased until mid-May, and remained fairly constant thereafter (Fig. 34). Unlike most mallard populations, a substantial percentage of the males appeared to be paired and the females not nesting throughout the nest initiation period. Fifty-four mallard broods were encountered and aged. Unlike 1987, mallard hatch dates showed a peak during the week of 29 May-4 June (Fig. 35). Weather Average January temperatures were 6.3 C below normal, February temperatures were 3.1 C below normal and March temperatures normal. Precipitation was normal for all 3 months. Daily temperatures at Alamosa airport display wide differences in maxima and minima and large day-day variations (Fig. 36). Snow cover persisted until late February (Fig. 37). DISCUSSION - 1986-87 Environmental conditions in the SLV during the 1986-87 winter probably were more severe than normal in the SLV. Mean daily temperatures were below normal and precipitation above normal in January and February (Table 8). Snow depth influenced foraging patterns of mallards wintering on the MVNWR. Snow covered all grain fields within about 15 km radius of the refuge. Consequently, the only grain available was that unharvested grain grown on the refuge. In these fields, the grain heads protruded above the snow, but were quickly removed by the estimated 17,000 ducks and 2,000 Canada geese (Branta canadensis) wintering on the refuge. When the 35 cm of snow fell during the 15-17 January, very little grain was available to foraging birds. Refuge personnel bladed snow off portions of the fields several days after the snow fell, but I suspect that grain made available was rapidly depleted. As a result, I believe that mallards wintering on the MVNWR were both thermally and nutritionally stressed during January and February. Although mortality rates for instrumented birds are high and represent minimal estimates, they may not be excessively higher than population mortality rates in the SLV. Approximately 250 wings were collected during radio-tracking and carcass searches. A crude Lincoln-Petersen index based upon the number of mortalities of instrumented birds found during these collections without using the transmitter to locate the carcass suggests that only about 10% of the carcasses were found. Therefore, some 2,000 to 2,500 mallards are estimated to have died on MVNWR from December through April. Refuge counts (Ed Merrit, personal comm.) do not show noticeable declines during this period, but because immigration and emigration of birds occurs regularly, weekly counts may be unreliable for quantifying winter mortality. Fifteen mortalities occurred during the week 8-14 February (Fig. 2). Mild weather during this period made it unlikely that environmental stress was proximate cause. Since the number of raptors in the SLV increased during this period, predation rates may have increased thereby reducing survival of instrumented birds. Mortality which occurred the week after all the birds were , �113 20 fn 0 0 0 ex: CD 16 II. 0 ex: &LI CD 10 :;! :;) Z 6 o MAY 16 JUNE 1 JUNE 16 JULY 1 WEEK Figure 35. Estimated hatching dates of mallard broods encountered In the San Luis Valley, Colorado, In 1988. Deily Mexlmum 20 Deily Minimum .•... o .•... &LI a: :;) 10 o ••• <t a: &LI e, # ,.,1 " -10 &LI It ,. -20 •~ •• • ,,\ , I , I, -30 I., " , " • .' ' , 1", • ., : I ,: '"'. ,,' , , \,' , ,.' • ", , • , , ,I \' 'I' ' ' I .' " " • _, I' - ',' '..! ",, .' .-' , v , " .len 16 , Feb 1 F.b 16 Mar 1 DATE Figure 36. Dally temperature '"' ' , " ,.! " .,' I I !" ...,' ,, I, " ,,, '. , ", . .,.,, , " " II L I. " •• , • :;! ••• ",",_. " • \ I , ,~ I, maxmlma and minima recorded Alamosa airport, Alamosa, Colorad, 1988. at the Mer 16 Mar 30 �114 ~ ~ ~ ~ ~ ~ ~ ~ 0 ~ % --, L-, ~ .... ~ 10 •••• 0.. rI L...., ~ W 0 0 == Z ~ , ...___, (/) 15 U - ~ , o I I I I Jan 1 Jan 115 Feb 1 Feb 115 , I Mar 1 I I Mar 115 I Mar 30 DATE Figure 37. Depth of snow on the ground at the Alamosa airport during winter, 1988. , �115 instrumented probably resulted from 18 inches of snow which covered foraging areas, low ambient temperatures, and remnant effects from handling stress. Of the approximately 70 birds alive in May at the start of the nesting season, only 31 could be located; 29 in the SLV, and 2 in the Gunnison Drainage. Most of the remaining birds probably migrated from the SLV, although the possibility of these birds not being located due to radio failure or unlocated mortality can not be discounted. Searches of North and South parks, intermountain wetlands north of the SLV, and a portion of the Front Range around Fort Collins failed to located any instrumented birds. The reasons for low winter survival rates and poor reproductive effort among the marked population are not apparent. The physical effect of the transmitter package is one potential reason, although the transmitter package was identical to those successfully used in other studies of breeding ducks (eg. Ringelman 1980, Cowardin et al 1985). Nevertheless, the transmitter package may have influenced both the mortality estimates and the reproductive effort in subtle ways. For example, the harness which hold the transmitter in place may make the bird reluctant to fly for a few days after attachment. Consequently, instrumented birds may be more likely to forego field-feeding flights until they have adjusted to the harness. During this time the bird is utilizing endogenous reserves. Thus, birds in "poor" condition which do not have reserves to survive long without foraging become weak, and are more likely to die than birds with more reserves or those making regular field-feeding flights. "Good" condition birds may become "poor" as their lipid reserves are depleted. It is unlikely that a bird could maintain a positive energy balance without making field-feeding flights. Counts of pairs and lone drakes indicated a prolonged nesting period for mallards in the SLV. This is reflected in prolonged hatching dates, lasting from mid-May through mid-July. Such a hatching curve may result from nonValley residents arriving on the nesting grounds in good condition and initiating nests earlier than mallards resident during winter. DISCUSSION - 1987-88 Condition indices and weights were similar to those recorded in 1987. Whether mean weights and condition indices are representative of the population or biased low is unclear. Although sample sizes are relatively large, most birds were caught in bait traps, which appear to capture more "poor" condition birds. Although weights of birds recaptured less than 7 days after initial capture were not significantly different between the 2 captures, the possibility of a handling effect can not be discounted. Weights of immatures recaptured during different trapping periods tended to be lower than unmarked birds, yet recaptured adult males had similar weights to unmarked birds. This may result from lower condition immatures being more likely to be retrapped or handling stress may cause a weight decline. A similar relationship was not observed among adult males. Too few adult females were recaptured to identify any relationship. The tendency for a male in a relative condition class 1 year to be in the same relative class the next year suggests that some males are be more efficient than others in balancing their energy budget and that these differences continue through time. The lack of any relations for females is probably a result of small sample sizes. As in 1987, winter mortality of mallards in the SLV was extremely high. Although the outbreak of fowl cholera and an increased field effort caused us �116 to find more dead mallards this year than last, survival rates of instrumented females were similar between the 2 years (65 of 105 (62%) instrumented in January died in 1987 and 69 of 108 (64%) instrumented in January and February 1988). Assuming that 30% of the dead birds were found, we project that 14,000 mallards died from January-March 1988. Given that 24,000 mallards were censused on 28 January,' the mortality rate exceeds 50% assuming no birds migrated into the SLV. However, an unknown number of mallards migrate through the SLV during spring. Pintails begin migrating into the SLV in early February, and migrant mallards probably begin arriving at the same time. If an appreciable number of migrants succumbed to avian cholera in the SLV, that might account for the significant difference in ulna lipids of marked and unmarked wings. The banded birds were known to winter in the SLV, and 14.6% of them had starvation levels of lipids in the ulna. Only 4.6% of the unmarked wings had starvation levels. Perhaps the difference results from migrants in better condition than winter residents forming the bulk of the February and March cholera fatalities. Without more information on the arrival dates and numbers of mallards migrating into the SLV it is difficult to evaluate any effect the mortality may have on the number of mallards wintering in the SLV. As in 1987, only 2 instrumented birds nested, both in "poor" condition when captured. Whether this low number of winter residents nesting is representative of the population or an artifact of instrumentation remains to be answered. The large number of paired males throughout the nesting season (Fig. 28) suggests there may be a significant non-nesting component in the population. If so, then the instrumented females may be representative of the population, and most of the production occurring on MVNWR results from migrants. Alternatively, data from the instrumented females which were collected suggest the radio package may influence the weight dynamics of the instrumented birds (Fig. 16). An instrumented female may drop in weight below some threshold needed for breeding. These two hypotheses are not mutually exclusive, and the true "answer" is probably a combination of poor reproductive success of winter residents and the radio package influencing weight dynamics. Unlike the 1987 results, no apparent relationship between survival and con9ition at the time of instrumentation was found this year, although power of the statistical tests used were generally low (Tables 8 and 9). Cholera may have masked any relationship since body condition is known not to alter susceptibility to cholera (Wobeser 1981). With the large number of carcasses available, predators such as bald eagles probably scavenged more than they hunted. Consequently, predation, which may have been related to the survival process in 1987, was probably minimal. The standard metabolic rate measurements suggest that acclimation of metabolic rate to low environmental temperatures occurs in mallards. The mean standard metabolic rate at -9 to -10 C of 673 Kj/day is 49% of the rate estimated from Smith and Prince (1973) at -10.9 C. This provides a substantial energetic savings to mallards wintering in the SLV. To meet this minimum daily requirement, a mallard would have to consume 57 g of steptoe barley or field peas for maintenance. Unfortunately, without information on time in field and flight for individuals, no reliable estimate of energy expenditure can be made. Estimates of these two variables, as well as additional time budget data in fields and at roosts, should be top priorities in developing an energy budget for mallards wintering in the SLV. �117 LITERATURE CITED Altmann, J. 1974. Observational 49:227-267. study of behavior: sampling methods. Behaviour Burnham, K. P., D. R. Anderson, G. C. White, C. Brownie, and K. H. Pollock. 1987. Design and analysis methods for fish survival experiments on release-recapture. Am. Fisheries Soc. Monogr. 5:1-437. Dill, H. H., and W. H. Thornberry. 1950. A cannon projected capturing waterfowl. J. Wildl. Manage. 14:132-137. based net trap for Dodge, W. E. 1985. A telemetry antenna mount for Cessna-type aircraft -construction details. U. S. Fish Wildl. Serv., Res. Inform. Bull. 85-126. 4pp. Dwyer, T. J. 1972. An adjustable 43:282-284. radio package for ducks. Bird-Banding Gollop, J. B., and W. H. Marshall. 1954. A guide for aging duck broods field. Mississippi Flyway Tech. Sect. 14 pp. Greenwood, R. J. 1977. Evaluation Manage. 41:582-585. in the of a nasal marker for ducks. J. Wildl. Hensler, G. L., S. S. Klugman, and M. R. Fuller. 1986. Portable microcomputers for field collection of animal behavior data. Wi1dl. Bull. 14:189-192. Soc. Hopper, R. M., A. D. Geis, J. R. Grieb, and L. Nelson, Jr. 1975. Experimental duck hunting seasons, San Luis Valley, Colorado, 1963-70. Wildl. Monogr. 46. 68pp. Hutchinson, A. E., and R. B. Owen. 1984. Bone marrow fat in waterfowl. Wil~l. Manage. 48:585-591. Lee, E. T. 1980. Statistical methods for survival Learning Publ., Belmont, CA. 557 pp. data analysis. Miller, M. R., and K. J. Reinecke. 1984. Proper expression energy in avian energetics. Condor 86:396-400. National Colorado Oceanic and Atmospheric section. 92(1):1-14. Administration. J. Lifetime of metabolizable 1988a. Climatological 1988b. Climatological data. Colorado section. 92(2):1-14. 1988c. Climatological data. Colorado s~ction. 92(3):1-14. data. Ringelman, J. K. 1980. The breeding ecology of the black duck in south-central Maine. Ph. D. diss., Univ. Maine, Orono. 68pp. Ringelman, J. K., and M. R. Szymczak. 1985. A physiological for wintering mallards. J. Wi1d1. Manage. 49:564-568. condition index �118 LITERATURE CITED (CONT.) Rutherford, W. H., and C. R. Hayes. 1976. Stratification improving waterfowl surveys. Wi1d1. Soc. Bull. 4:74-78. SAS Institute, Inc. 1982. SAS users guide: statistics. Cary, NC. 584 pp. -----. 1985. SAS procedures Cary, NC. 373 pp. guide for personal as a means for SAS computers, Institute, version Inc., 6 edition. Smith, K. G., and H. H. Prince. 1973. The fasting metabolism of subadu1t mallards acclimatized to low ambient temperatures. Condor 75: 330-335. .. Szymczak, M. R. 1986. Characteristics of the duck populations in the intermountain parks of Colorado. Colorado Div. Wi1d1., Tech. Pub1. 35. 88 pp. -----and J. F. Corey. 1976. Construction and use of the Salt Plains duck trap in Colorado. Colorado Div. Wi1dl., Div. Rep. 6. 13pp. Wobeser, 300pp. Prepared G. A. 1981. Diseases of wild waterfowl. b~uZ~L~K. Wildlife Ringe~ Researcher C Plenum Press, New York, NY. �119 Appendix A. Condition index means for 9186-87 by date and age-sex class. The October and November samples are from hunter-killed birds. all other birds were trapped in Salt Plains Bait traps. Date Adult female Male n Mean(SD) n Mean(SD) n 10/4/86 7 21.2(3.8) 19 21.2(3.6) 3 10.0(12.2) 8 14.6(3.1) 11/1/86 1 26.2 13 22.2(2.2) 5 24.7(4.8) 7 23.0(2.1) 12/17/86 2 14.7(1.7) 9 16.4(1.9) 12/18/86 5 18.0(2.9) 25 19.3(2.5) 10 17.3(3.9) 10 15.8(4.7) 12/19/86 8 23.7(2.4) 16 18.7(5.2) 3 22.4(2.7) 14 18.1(3.3) 12/20/86 3 16.2(3.2) 28 17.0(3.4) 17 16.1(4.8) 39 16.1(3.7) 1/5/87 22 13.0(6.6) 134 12.6(4.5) 28 13.7(4.1) 82 12.3(4.9) 1/6/87 19 13.0(4.4) 41 13.4(3.0) 44 12.6(3.3) 46 12.4(3.7) 1/7/87 13 14.2(4.3) 66 11.8(3.6) 34 13.4(4.0) 75 10.0(3.8) 1/8/87 13 15.9(3.5) 102 12.1(3.5) 52 15.3(3.8) 122 11.5(3.8) 13.8(3.6) 11.7(6.2) Immature Male female n Mean(SD) Mean(SD) 1/9/87 3 13.6(7.3) 9 1/10/87 13 15.7(3.5) 1 1/11/87 10 14.9(5.4) 1/13/87 9 11.5(3.7) 1/14/87 6 12.4(4.2) 1/15/87 13 11.9(2.9) 2/5/87 13 12.5(3.8) 49 11.4(3.6) 28 13.7(3.7) 2/20/87 23 14.9(3.4) 52 11.8(3.0) 67 13.3(3.8) 40 11.3(3.4) 2/21/87 33 14.8(4.0) 112 9.7(3.5) 2/22/87 13 13.4(3.2) 3 6.7(1.4) 3 16.0(2.7) 3/18/87 1 19.4 9 8 14.8(2.0) 6.9 1 1 2.4 15.8 2 13.8(3.5) 36 12.0(3.0) 2 14.3(2.3) 176 9.3(3.6) 3 12.2(2.5) 7 12.7(4.5) �120 Appendix B. Capture histories of instrumented birds from week 1 (Jan. 11-18) through week 11 (March 20-26), 1988. One indicates that the bird was contacted and alive during the week, 0 that the bird was not contacted, and -1 that the bird was found dead during the week. Band 145795333 139719963 139719970 145796710 145795521 145796805 139719567 145796729 145795202 145796788 139719863 145796305 145795731 145796736 139719562 145796791 139719851 145795408 145796295 145796730 139719534 145796711 145795597 139719596 145796251 145795157 145796745 145795198 145796055 145795620 145796287 145796636 145796707 145795058 139719969 145796802 145795548 145796874 145795093 145796307 139719902 145795605 freq 150.010 150.021 150.050 150.050 150.072 150.072 150.100 150.100 150.140 150.140 150.180 150.180 150.187 150.187 150.200 150.200 150.210 150.219 150.219 150.219 150.259 150.259 150.281 150.290 150.290 150.300 150.300 150.311 150.320 150.341 150.341 150.341 150.353 150.362 150.370 150.370 150.402 150.402 150.420 150.420 150.435 150.452 CI 14.3 8.3 11.2 19.3 19.6 10.0 19.2 16.5 7.2 14.0 18.8 12.6 19.3 15.0 22.1 9.8 6.9 13.2 12.2 18.1 11.1 16.0 14.6 20.0 20.5 14.3 18.3 13.7 22.7 23.9 17.6 18.0 17.6 21.0 11.8 14.9 18.7 10.5 21.4 13.0 7.8 19.1 week: 1 2 3 4 5 6 7 8 9 1 1 1 -1 1 1 1 1 -1 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 1 1 1 1 -1 1 1 -1 1 1 -1 1 1 1 -1 1 1 -1 1 1 10 11 1 -1 1 1 1 -1 1 1 1 1 1 1 1 1 1 1 1 0 1 -1 1 1 1 -1 1 -1 1 1 1 1 -1 1 1 1 -1 1 1 1 -1 1 1 1 1 1 0 -1 1 1 1 0 1 0 -1 1 -1 1 1 1 0 1 1 1 -1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 1 1 1 1 1 -1 1 1 1 1 -1 1 1 1 1 1 1 1 1 1 -1 1 1 -1 1 1 1 1 -1 1 1 1 1 1 -1 1 1 1 1 1 1 1 1 1 1 1 1 �121 Appendix Band 145796744 145795405 145795595 145795604 145795403 139719810 145796797 145795277 145795079 145795203 145796706 139719846 145796732 145795488 145796615 139719589 145795110 145796302 145796795 145795409 145795274 139719932 145796719 145795275 145796306 145796689 145795300 145796705 145795220 145796724 145795291 145796309 145796865 139719668 145795476 145796833 145795067 145796470 145795059 145795603 145796631 139719685 145795592 145796622 145795104 145796275 139719590 B (cont.). freq 150.452 150.483 150.491 150.534 150.541 150.560 150.560 150.570 150.595 150.601 150.601 150.617 150.617 150.620 150.620 150.630 150.652 150.652 150.652 150.662 150.670 150.680 150.680 150.700 150.700 150.700 150.710 150.710 150.719 150.719 150.730 150.730 150.730 150.740 150.753 150.753 150.761 150.761 150.770 150.782 150.782 150.802 150.815 150.815 150.838 150.838 150.849 CI 19.3 14.4 14.9 19.7 13.8 14.5 9.6 10.0 21.5 14.1 17.1 18.8 11.7 21.0 18.3 11.6 19.4 10.6 10.0 12.7 20.9 10.9 16.9 8.0 10.4 19.2 9.9 15.7 2.3 15.8 19.9 19.4 8.1 13.8 15.0 14.4 21.0 16.7 18.9 11.9 16.0 18.9 25.3 19.5 9.7 8.6 7.3 week: 1 2 3 4 5 6 7 8 9 10 11 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 -1 1 1 1 1 1 1 1 -1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 -1 0 1 0 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 1 1 1 1 1 1 1 -1 1 1 1 1 1 1 1 1 -1 1 1 1 1 1 -1 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 1 -1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 -1 1 1 -1 1 1 -1 1 1 -1 1 1 -1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 -1 1 -1 1 1 1 -1 1 1 1 1 1 -1 1 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 1 1 1 1 1 1 1 1 -1 1 1 1 1 1 1 1 1 i 1 1 1 1 -1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 1 -1 1 1 1 1 �122 Appendix B (cont.). Band 145796301 145796735 145795490 145796283 145795622 145795589 145796876 139719820 145796688 139719514 145796276 145795332 145796836 145795065 145795404 145796274 145796769 139719958 145796310 145796692 145795047 145796737 145795480 145795371 145796625 145795276 145795106 145796734 139719832 139719848 139719951 145796838 139719859 139719831 139719699 145796786 139719955 145796293 145795086 145796279 145796294 145796794 139719906 139719968 139719533 145796501 145795064 freq 150.849 150.849 150.864 150.864 150.874 150.884 150.884 150.900 150.900 150.928 150.928 150.945 150.945 150.952 150.964 150.964 150.964 150.977 150.977 150.977 150.987 150.987 150.999 151.006 151.006 151.020 151.029 151.029 151.041 151.050 151.074 151.074 151.080 151.093 151.110 151.110 151.122 151.122 151.141 151.141 151.141 151.141 151.154 151.161 151.170 151.170 151.184 CI 12.7 15.3 18.6 9.7 21.6 22.3 7.3 19.7 19.5 10.3 ·1.0 9.5 14.4 20.0 11.7 18.7 8.0 14.9 6.9 21.8 14.8 16.8 12.4 13.0 22.8 22.1 19.0 19.7 20.2 19.0 19.3 23.2 13.5 20.1 13.6 8.7 8.9 3.0 9.1 21.1 13.3 13.5 9.2 14.0 21.8 9.6 18.4 week: 1 2 3 4 5 6 8 9 10 11 1 1 1 1 1 0 1 0 1 0 1 0 1 1 1 1 1 1 1 1 1 1 1 1 ·1 1 1 1 1 1 ·1 0 1 1 -1 1 1 ·1 7 1 ·1 1 ·1 1 1 1 1 1 1 1 1 1 0 1 ·1 1 1 1 ·1 1 0 1 0 1 ·1 1 1 0 1 1 1 1 1 1 1 ·1 1 1 1 1 1 1 1 ·1 1 ·1 1 1 ·1 1 1 -1 1 ·1 1 1 1 1 1 1 -1 0 -1 1 1 1 1 1 1 1 1 1 1 1 -1 1 -1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 1 1 1 1 0 1 0 1 0 1 1 1 1 1 1 1 0 1 -1 1 1 1 1 1 1 1 1 -1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 0 1 0 1 1 -1 1 1 1 1 1 1 1 1 1 -1 1 1 1 1 1 ·1 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 1 ·1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ·1 1 -1 1 ·1 , �123 Appendix B (cont.). Band freq 145796304 151.184 145796453 151.184 139719876 151.196 145796503 151.200 145796474 151.211 139719621 151.212 145796498 151.212 139719971 151.222 145796796 151.222 139719674 151.230 145795323 151.240 145796443 151.250 145795062 151.259 145796478 151.261 145795413 151.270 145796852 151.270 139719627 151.280 145796297 151.280 145796725 151.280 145795281 151.289 145796458 151.289 145796451 151.290 145795066 151.310 145795458 151.328 145796811 151.328 145795288 151.356 145796857 151.356 139719908 151.377 145795546 151.386 1457..96303 151.386 139719845 151.400 145796626 151.400 139719967 151.441 145796292 151.441 145795103 151.472 145796747 151.472 145796500 151.519 145796465 151.529 145795337 151.540 145796863 151.540 145795558 151.570 145796476 151.575 145795701 151.607 145795594 151.623 145796806 151.623 145795339 151.635 139719673 151.730 CI 7.3 8.4 14.3 16.2 8.2 12.3 18.3 23.5 12.6 20.3 19.0 16.8 19.1 7.4 19.6 12.8 11.3 8.4 23.0 12.6 18.1 8.9 21.0 14.2 9.4 20.0 22.9 13.2 19.4 11.0 13.9 24.5 11.5 20.5 19.3 11.3 15.8 10.2 10.3 15.0 23.6 21.2 21.5 21.9 12.8 17.9 13.0 week: 1 2 3 4 1 1 1 5 6 1 1 -1 7 8 9 10 11 1 1 1 1 1 1 1 0 1 1 1 1 1 1 -1 1 1 0 1 1 1 1 1 1 1 0 0 1 1 0 0 1 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 1 1 1 1 -1 1 1 1 1 0 -1 1 1 1 1 1 0 1 1 0 -1 1 1 -1 1 1 0 1 1 0 1 -1 1 0 1 0 1 -1 1 1 1 1 -1 1 1 1 -1 1 1 1 1 1 1 1 1 1 -1 1 1 1 1 -1 1 1 1 1 1 -1 1 1 1 1 1 1 1 -1 1 0 -1 1 1 1 1 1 1 1 0 1 1 1 0 1 1 1 1 -1 1 0 0 0 0 0 1 0 0 0 1 1 .1 1 1 1 1 1 1 1 1 1 1 1 -1 -1 1 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 1 1 1 1 1 1 1 1 1 -1 1 1 1: 1 1 1 -1 1 1 -1 1 -1 �124 Appendix B (cont.). Band 145796311 145796467 145795590 145796742 139719850 145795577 145795335 145796184 freq 151.730 151.730 151.773 151.773 151.876 151.912 151.924 151.924 CI 11.2 7.1 14.5 18.1 21.1 19.8 20.3 19.6 week: 1 2 3 4 1 5 6 7 8 9 10 11 0 -1 1 -1 1 1 0 -1 1 1 1 1 0 0 1 -1 1 1 1 1 1 1 1 1 1 1 o 1 -1 1 1 1 1 1 1 1 1 1 1 , � https://cpw.cvlcollections.org/files/original/d5c034181db0298fc427c4ccfa1e11d7.pdf ff3220abcca37ff4c81ac14b26e86227 PDF Text Text 1 Colorado Division of Wildlife Wildlife Research Report April 1989 JOB PROGRESS REPORT State of: Colorado Project: __ W~-~1~5:2_-~R Work Plan: 3__ : Job Job Title: Responses Period Covered: Author: _ Upland Bird Research 13 of Sage Grouse to Vegetation 01 January through 31 December Fertilization 1988 Orrin B. Myers Personnel: C. E. Braun, S. Porter, K. Snyder, Colorado Division o. B. Myers, G. C. White, Colorado State University; of Wildlife; C. Cesar, L. Upham, U.S. Bureau of Land Management ABSTRACT The response of sagebrush (Artemisia tridentata) and sage grouse (Centrocercus urophasianus) to nitrogen fertilization was studied in North Park, Jackson County, Colorado. Sagebrush plants responded to application of 112 kg-Nfha in Fall 1985 with increased growth, increased levels of foliar crude protein; and reduced levels of foliar coumarins. Application of fertilizer in Fall 1987 produced a less dramatic response. Sage grouse used fertilized study plots for feeding more (f < 0.05) often than adjacent unfertilized plots. When presented with fertilized and unfertilized A. ~. wyomingensis (ATW) and A. ~. vaseyana (ATV) in paired choice experiments, captive sage grouse consumed more (f < 0.05) ATW treatments than ATV treatments. Sagebrush treatments were digested at similar rates. Clutch sizes were not related to distance to nearest fertilized plot and the survival distribution for hens near fertilized plots was not different from birds using other areas of North Park. ��3 RESPONSES OF SAGE GROUSE TO VEGETATION FERTILIZATION Orrin B. Myers P. N. OBJECTIVES The project is part of a two-phased study to on sage grouse winter distribution in mining ecology, and to 2) evaluate whether nitrogen grouse winter habitat, can be used as a tool available to sage grouse. The focus of this Phase 2. 1) collect baseline information areas and on grouse feeding fertilizer, when applied to sage to mitigate reduction in habitat portion of the project is on SEGMENT OBJECTIVES 1. Document chemical fertilizer, and growth response of sagebrush 2. Evaluate feeding preferences of sage grouse for fertilized unfertilized sagebrush subspecies, 3. Estimate digestibility subspecies, and 4. Monitor reproductive parameters of radio-marked sage grouse to learn if sage grouse fitness is affected by fertilizer treatment. of fertilized to nitrogen and unfertilized and sagebrush DESCRIPTION OF STUDY AREA The study area is in North Park, Jackson County, Colorado. The Park is an intermountain basin at an elevation of about 2,500 m. It is drained to the northwest by the North Platte River, which is fed by many smaller streams. Topography is flat to rolling with numerous ridges and benches. Climate is cold and dry with an average annual frost-free period of 46 days. Sagebrushdominated grasslands cover upland sites in the Park, and grasses and sedges occur in native and irrigated meadows that border drainages. Artemisia tridentata is the dominant sagebrush species and includes 2 subspecies, ft. ~. wyomingensis (ATW) and ft. ~. vaseyana (ATV). Other species of sagebrush occurring with limited distribution in North Park are ft. longiloba, ft. cana, and ft. argillosa. METHODS In October-November 1985 ammonium nitrate fertilizer (33.5% N) was applied at a rate of 112 kg-Nfha to 330 ha of sagebrush rangeland (Fig. 1). Thirty-three 20-ha blocks were randomly-selected with 11 blocks distributed in each area. The northern and southern 10 ha of each block were randomly assigned as fertilized or control and treated accordingly. In October 1987 fertilizer was applied to an additional 6 l-ha plots (Fig. 1). The 3 main study areas contain similar densities of sagebrush plants, but the proportions of ATV and ATW differ between areas (Fig. 2). �4 A JACKSON COUNTY 1987 1985 Gill II D 0 FERTILIZED CONTROL ~ 1 km 1. Colorado. Fig. A Fertilized + study plots in North Park, Jackson County, B c D ATW ATV 3,20 3,11 3,53 TOTAL 2 PLANTS/m 2. Relative densities of sagebrush subspecies on each of 3 main fertilized study areas in North Park, Jackson County, Colorado. Fig. �5 Sagebrush foliage was collected each quarter from a random sample of the 33 experimental blocks. Four blocks from each of the main study areas were sampled and 5 randomly-located plants of the 2 big sagebrush subspecies were clipped from the control and fertilized halves of each study block. Sage grouse use of study blocks was estimated by examining individual plants for evidence of feeding activity. The characteristic appearance of leaves that have been fed upon by grouse has been described (Remington and Braun 1985). Equal numbers of each subspecies were examined along pace transects through the control and fertilized portions of randomly selected study blocks. Sampling points were at random distances along transects. Sage grouse were trapped at nocturnal roosts to attach radio transmitters and to provide birds for captive experiments. Fertilized study areas were scanned periodically for radio-marked birds prior to the breeding season and ~ 3 times weekly during the breeding season. Radio-marked birds also were located periodically to assess any use of experimental blocks and to monitor reproductive success. Survival probabilities of female sage grouse were estimated for radio-marked hens. Survival functions were estimated using the Kaplan-Meier product-limit method (SAS Inst. Inc. 1988). Survival time (days) from 15 April to date of death (failure date) were used in computations. Annual survival probability estimates were bracketed by right censoring observations on the date of last radio contact and then by setting failure date equal to date of last radio contact. The procedure assumes animals are sampled randomly, that survival times are independent for different animals, that radio packages do not influence survival times, that the censoring mechanism is random, and that emigration or radio failure is zero (Pollock et al. 1989). Male and female grouse were counted on leks between about 0500 and 0730 from 01 April through the first 2 weeks of May. Ground searches were made for new or relocated leks. Feeding trials were conducted with captive sage grouse to estimate feeding preferences for and digestibility of Wyoming big sagebrush, Artemisia tridentata wyomingensis, (ATW) and mountain big sagebrush, a. ~. vaseyana, CATV). Two levels of fertilization also were tested: no fertilization (ATW and ATV) and 112 kg-Njha (FATW and FATV). The 6 possible 2-way combinations of the 4 sagebrush treatments were presented to each bird in random order to evaluate feeding preference for the different treatments. Sagebrush foliage was removed from stems and given to birds in a 400 ml beaker. For each trial similar amounts of 2 treatments were placed on the left or right side of each cage prior to the morning feeding period. Positions of each treatment in the cages were determined randomly and switched in subsequent trials. Birds were allowed to feed for 60 minutes after which the sagebrush and spillage were removed and weighed. Digestion trials were accomplished by adding known amounts of sagebrush to cages at about sunrise. Sagebrush foliage also was placed on top of cages in the morning and weighed at night to provide an estimate of water loss during the day. After the evening feeding period sagebrush was removed from the �6 cages and weighed. Spilled sagebrush was removed from the bottom of the cage, weighed and discarded. Fecal droppings were collected and stored overnight in resealable plastic bags. Fecal and cecal droppings were collected and placed into plastic bags before additional sagebrush was added to cages the following morning and subsequently placed in frozen storage. Between trials, birds were maintained on sagebrush and a commercial ration (12.5% crude protein and 10.0% crude fiber). Sagebrush foliage samples were prepared for analyses by separating leaves from sterns and pooling equal amounts of leaves from each plant into composite samples. Composite samples for each subspecies collected on the control and treatment halves of each study block were ground using a mortar and pestle after freezing with liquid nitrogen. Composite foliage samples collected during feeding trials were treated in the same manner. Grouse fecal and cecal droppings collected during feeding trials were freeze-dried and ground using a mortar and pestle. Coumarin content of winter-collected sagebrush leaves was indexed following Welch and McArthur (1986). In this method, percent transmittance values were produced and were assumed to be inversely related to the coumarin content of sagebrush leaves. Dry matter content of foliage and grouse droppings was determined after drying overnight at 100 C. Samples were ashed overnight at 500 C to determine organic matter and ash content. Kjeldahl nitrogen (Horwitz 1980) was measured in addition to neutral detergent fiber, acid detergent fiber, and lignin (Van Soest 1963~, Q; Mould and Robbins 1981, Van Soest 1982). Soil samples were collected from each of the 6 study plots prior to receiving nitrogen fertilizer in Fall 1987. Adjacent control plots also were sampled. Each plot was subsampled at 6 random locations. Subsamples were placed into a plastic bucket and thoroughly mixed before removing about 750 cc for analyses. Analyses of soil samples were performed by the Soil Testing Laboratory at Colorado State University. RESULTS Feeding Trials Two birds each from Colorado and from Wyoming were used to collect data on feeding choices by grouse and on forage digestibility. The Wyoming birds were from a captive flock maintained at the University of Wyoming at Laramie and the Colorado birds were captured in North Park. The Colorado birds were 2 of 4 birds captured in North Park for use in trials and were those that adapted best to captive conditions. All birds lost weight initially and then gained weight as they acclimated to captive conditions. Colorado birds were slower to recover lost body mass than Wyoming birds (Fig. 3). For the Colorado birds an important factor in maintaining condition was their acceptance of the commercial ration. Body mass was monitored daily during the digestion trials. Birds lost more weight when fed ATV treatments than when fed ATW treatments, regardless of fertilizer status (Table 1). However, birds also consumed less sagebrush when given FATV or ATV than when fed FATW or ATW (Table 2). When body mass changes were plotted against daily intakes (Fig. 4) the slopes were similar (~ = 0.8, ANCOVA test for heterogeneity of slopes). Thus, for a given level of intake changes in body mass were the same regardless of the treatment consumed. �7 1500 WYOtfING COLORADO 1400 1300 1\ r» '-.J (f) (f) 1200 --- "', « ::2 >0 <, 1100 ~ ----, 0 rn \. \ 1\ \ / \ v 1000 \ \ \ \ ,- 900 -- <, \ J " \{ _-\ -> ,/ 800 02/07 02/27 03/ 18 04/07 DATE Fig. 3. Performance of sage grouse used in feeding trials during 1988. Birds were obtained from wild stock in North Park and from the University of Wyoming captive flock. Table 1. treatments Body mass changes (g/d) of captive sage grouse fed 4 sagebrush during 1988 digestion trials. Subspecies fed [1. SE !,. wyomingensis Control Fertilized [1. .& (n (n 4) 4) -44 -41 7 5 (n (n 4) 4) -61 -60 9 1 !,. vaseyana Control Fertilized Source Fertilizer (F) Subspecies (S) F x S interaction df 1,12 1,12 1,12 > f f value f 0.13 8.52 0.04 0.7 0.01 0.8 �8 Table 2. Consumption of sagebrush treatments sage grouse during 1988 digestion trials. Subspecies (g fresh weight) by captive fed SE ~ . .t. wyomingensis Control Fertilized (n = 4) (n 4) 55.8 58.6 6.8 6.6 (n (n 39.8 36.2 6.7 4.2 ~ . .t. vaseyana Control Fertilized 4) 4) Source df Cage Fertilizer (F) Subspecies (S) F x S interaction 3,9 1,9 1,9 1,9 E value f > E 2.67 0.01 13.83 0.38 0.11 0.94 0.01 0.55 -20 -30 r--. -'10 bl • ATV <> ." ATVI rATV A FAT¥ c X = 0.45~ - A 68.5 <:» Ii:j CJ -50 !z; ..:r: ~ -60 E-< ::r:: Cl -70 U X= H Ii:j :;;t: 0.55X - Bl.6 -80 • -90 20 30 '10 INTAKE Fig. 4. sagebrush 50 50 70 (g) Daily changes in body mass of captive sage grouse fed 4 treatments in relation to daily intakes. �9 Dry matter intake during digestion trials also was not influenced by fertilization (£ > 0.7) but birds consumed more of the ATW treatments than of the ATV treatments (£ < 0.01). When adjusted for different intakes, the amount of dry matter retained was not affected by subspecies or by fertilization (ANCOVA £ > 0.5). Dry matter digestibility coefficients were similar for each subspecies (£ > 0.1) and for each fertilizer treatment (£ > 0.5). Dry matter digestibility coefficients for ATV treatments were between a and 10%, compared to ATW treatments, which were between 25 and 32%. Nitrogen balance and amounts of retained energy also were not affected (£ > 0.05) by nitrogen fertilization or by subspecies. Sagebrush foliage used in 1988 feeding trials did not show any effects of fertilization treatment upon crude protein and gross energy (Table 3). ATW contained more crude protein (£ < 0.01) and less gross energy (£ <0.05) than ATV. Fertilized sagebrush contained similar amounts of acid detergent fiber (ADF) and natural detergent fiber (NDF) , and ATW contained more ADF than ATV (Table 4). Coumarin levels in foliage samples collected in May 1987 showed no effect due to fertilization (£ > 0.05), but subspecies were different (£ < 0.05) (Table 5). Table 3. Crude protein (% dry matter) and gross energy (cal/g dry matter) in sagebrush samples fed to captive sage grouse during digestibility and feeding preference trials. Three samples were analyzed for each treatment. Subspecies Treatment Crude 12rotein SE ~ Gross energy SE ~ a. _t. vaseyana Control Fertilized 9.6 10.1 0.6 0.2 5747 5628 61 21 a. _t. ~omingensis Control Fertilized 12.4 13.3 0.2 0.4 5520 5494 56 90 Table 4. Neutral (NDF) and acid detergent fiber (ADF) fractions in sagebrush samples fed to captive sage grouse during digestibility and feeding preference trials. Three samples were analyzed for each treatment. ADF NDF ~ SE R SE Control Fertilized 0.318 0.316 0.005 0.003 0.219 0.210 0.008 0.001 Control Fertilized 0.351 0.357 0.005 0.017 0.233 0.246 0.002 0.004 Subspecies Treatment a. _t. vaseyana a. _t. ~omingensis �10 Table 5. Coumarin levels (% transmittance) in sagebrush plants collected during May 1987 from fertilization study plots in North Park, Jackson County, Colorado. R Subspecies Treatment 6· .t. vaseyana Control Fertilized 10.9 11.0 1.9 1.6 t:, . .t. :'£lomingensis Control Fertilized 21. 9 25.3 2.4 1.9 SE Sage grouse fed upon some sagebrush treatments in greater amounts than on others (Fig. 5). Wyoming and Colorado birds consumed treatments in the same proportions. Birds consumed more (f < 0.05) FATW than ATV or FATV. Selection for ATW was weaker than for FATW when tested against ATV and FATV. Within a subspecies, birds consumed equal amounts of fertilized and control treatments. The apparent lack of selectivity for fertilized plants in contrast to 1987 trials could be due to smaller differences in plant chemistry between treatments than in 1988. Also, in the 1988 trials only leaves were presented to birds, so they were not able to use plant morphological differences to help choose plants. A D FATV mill ATW o = 0.2 P = 0.06 P c ~ FATW 1m ATW B D 1IIIIIIII ATW .~~:~w P = 0.001 P = 0.7 E8 ~ FATW FATY D FATV 0.5 P = 0.001 DATV ". D .. P = ATY F Fig. S. Relative consumption of sagebrush grouse during 1988 feeding trials. treatments by captive sage �11 Browse Transects A total of 240 sagebrush plants was examined for evidence of feeding activity by grouse (Table 6). Sage grouse fed upon ATW more often than ATV (X2 - 11.8, £ - 0.001) and fed upon fertilized ATW plants more often than on unfertilized plants (X2 - 10.4, £ = 0.001). Low numbers of ATV plants were fed upon in all study blocks sampled. Table 6. Numbers of plants examined along transects showing evidence of feeding activity on control and fertilized study plots in North Park, Jackson County, Colorado, 1988. Fed u~on b~ grouse No Yes Subspecies n a. ~. a. ~. % n % ~omingensis Control Fertilized 58 46 97 77 2 14 3 23 vase~ana Control Fertilized 60 58 100 97 0 0 2 3 Nesting Three marked hens from the North Park wintering population nested in southern Wyoming. One of the birds had been captured for use in the captive feeding trials and was released near the Walden Coal Company mine on 22 February. The bird had lost 25% of its original body mass when released. It is not known if any other birds left the study area to nest. Nesting sites were located for 21 hens. None of the nests was on fertilized plots, including 1 bird that nested in a fertilized plot in 1987. At the end of May, 4 nests were active, 11 had been destroyed, eggs in 2 nests had hatched, and eggs in 4 nests were collected for captive propagation. Four clutches were believed to have hatched. Egg predation by ground squirrels was apparent at most failed nests. The relationship between clutch size and proximity to fertilized plots was examined. A negative correlation between clutch size and distance to fertilized plots may indicate a positive treatment effect on clutch size. The slope for the regression of clutch size on distance was not different from zero (£ > 0.2) when years were considered separately or when combined (Fig. 6). �12 10 9 8 7 Ii:J N H (JJ 6 0 0 5 P:: U 8 ~ ,_:j U 4 o 1987 •••. 1988 3 2 1 0 0 DISTANCE Fig. 6. Colorado, 40 30 20 10 (kID.) Clutch size of sage grouse nests in North Park, Jackson County, in relation to distance to nearest fertilization study plot. Leks No new leks were located near the fertilized study areas. Peak male counts from leks active in 1988 were summed for all for each quadrant of North Park years since 1973 to provide an index to grouse population changes. Six leks in the NE quadrant were included and all were within about 5 km of fertilizer treatments. The number of leks summed in the NW, SE, and SW quadrants were 6, 2, and 10, respectively. If it is assumed that lek counts track population levels, leks in the NE (fertilized) fluctuated in much the same manner as leks in other areas of North Park (Table 7, Fig. 7). Table 7. Peak male counts on selected leks in quadrants of North Park, Jackson County, Colorado. Fertilized study blocks were in the NE Quadrant. Longterm R Quadrant NE NW SE SW (n (n (n (n 6) 6) 2) 10) 104 188 90 340 1985 1986 1987 1988 70 124 111 332 47 94 54 266 108 177 99 363 99 199 92 342 �13 800 NE SE NV FERTILIZER APPLIED SW 600 I \ I I I \ / \ -- I -- - \ / I \ \ 400 / /" / \ \ / / \ \ I 200 ,,/ / __ .... v \ ....... -._ ._-_._.-._.-- _ .-._ -., . / \ I \ \/:.~.~,,,/ -s;»: v''_'-'' _ -, o 72 74 76 78 80 82 84 86 88 90 YEAR Fig. 7. Total numbers of male sage grouse counted at selected leks in North Park quadrants. Fertilizer was applied in Fall 1985 in the NE quadrant. Survival Radio locations were obtained from 63 birds on 110 different dates during 1987 and 1988. Survival distributions did not differ between years (f> 0.2), and survival probabilities for birds captured in the northeast (0.612) and the northwest quadrants (0.700) were similar (f> 0.4). The annual survival probability for 15 April 1986 to 14 April 1987 was 0.67 (95% confidence interval = 0.52 - 0.0.83) compared to an estimate of 0.58 (95% confidence interval = 0.33 - 0.82) from 15 April through 31 December 1988. The combined annual survival probability was 0.300 (95% confidence interval = 0.184 0.416) when dates of last radio contact were treated as failure dates (Fig. 8), which was not different from the estimates for 1987 and 1988. Soil Chemistry The amount of nitrate-nitrogen (N03-N) in soils from plots fertilized in Fall 1987 was increased (f = 0.01) by fertilizer treatment (Tables 8, 9). Other soil characteristics were not affected by the treatment (f> 0.1). The amount of organic matter (OM) in Morset Loam was greater than in Bosler Loam (f = 0.03; Tables 10, 11), and Morset Loam contained more K than Bosler Loam (f < 0.01). Soil chemistry values also differed (f < 0.05) between Fall 1987 and June 1988 for pH, conductivity (cond.), OM, N03-N, P, Zn, Mn, and Cu. �14 1 0.9 >- f- 0.8 + + + _J m 0,7 « CO 0 + + 0.6 II 0... _J 0.5 « > > a: ::) 0.4 0.3 + (f) 0,2 0 100 200 DAYS AFTER 300 400 INSTRUMENTATION Fig. 8. Survival probabilities of sage grouse in Jackson County, Colorado and exponential fit to data that assumes last radio contact equals time of death. Table 8. Soil characteristics of experimental plots when treated with ammonium nitrate fertilizer in October 1987. n Control Treatment 6 6 pH 6.8 6.7 Condo (nmhos/cm) OM 0.18 0.15 3.1 2.9 N03~-N~__ ~P ~K~ __ ~Z~n ~F~e ~M~n~ C~u~ 3.0 2.9 2.2 2.1 (ppm) (%) 0.6 0.7 4.2 3.6 231 205 0.8 0.8 23.9 24.0 Table 9. Soil characteristics in June 1988 from experimental plots treated with ammonium nitrate fertilizer in October 1987. n Control Treatment 6 6 pH 7.5 7.2 Condo (nmhos/cm) 0.22 0.28 OM N03-N P K Zn (ppm) Fe Mn Cu 0.8 7.0 2.7 2.9 194 204 0.4 0.5 14.9 19.7 2.0 2.4 1.9 1.7 (%) 1.8 1.9 �15 Table 10. Soil characteristics in experimental plots when treated with ammonium nitrate fertilizer in October 1987. Soil series Bosler loam Morset loam n 4 8 pH 6.7 6.8 Condo (nos/em) 0.10 0.20 OM N03-N P K Zn (ppm) Fe 0.5 0.7 3.5 4.2 140 257 0.9 0.7 17.9 27.0 (%) 2.1 3.4 Mn Cu 3.1 2.9 1.8 2.3 Table 11. Soil characteristics in June 1988 from experimental plots treated with ammonium nitrate fertilizer in October 1987. Soil series n pH Bosler loam Morset loam 4 8 7.3 7.4 Vegetative Condo (nos/em) 0.25 0.25 OM (%) N03-N P K Zn (ppm) Fe Mn Cu 1.3 2.1 2.5 4.6 2.6 2.9 172 212 0.4 0.4 13.5 19.2 2.4 2.1 1.8 1.8 Response Both sagebrush subspecies responded to fertilization with increased length of stems and by producing larger leaves. Average plant height did not increase (f > 0.05) due to large variation among plants. Whole plant morphology, however, was affected by fertilization in other ways. The number of ephemeral reproductive stems was increased by fertilization, which was not included in plant height measurements. The effect of lengthened stems, more numerous and longer reproductive stems, and larger leaves caused plants on fertilized plots to appear substantially taller and more lush than plants on adjacent control plots. The impact of fertilization on sagebrush plants apparently was greater for the 1985 treatment than when fertilizer was applied in 1987. The appearance of 1987 plots seemed less lush than the appearance of plots fertilized in 1985. In each case length of new stems was increased by fertilization (Fig. 9), but response to fertilization by ATW plants was less dramatic for the 1987 treatment than for the 1985 treatment. It is possible that vegetative response was dependent on soil moisture conditions during the growing season after fertilizer application. Soil moisture levels were higher during the 1986 growing season (extensive snow fell during and after fertilization in Fall 1985) than during the 1988 season. �16 80 70 ,....., FI FI t 60 t t P=1 s- 50 c..? :z; I'Ll ....:l j 40 ~ I'Ll A ...: 30 PLl ....:l 20 t t t + 10 0 .L_L _g________r ATW ATV 1987 _g________r _g________r AT" ATV 1985 Fig. 9. Length of sagebrush new growth after 1 growing season. Following fertilization with 112 kg-N(ha. Data are means and 95% confidence intervals. DISCUSSION Captive sage grouse showed affinities for feeding on some sagebrush treatments over others. One method for estimating palatabilities of forages is to measure intakes during digestibility trials. This method demonstrated that sage grouse fed preferentially upon ATW treatments over ATV treatments and that fertilization was not a factor in feeding choices. The 1988 choice trials support the finding that within a subspecies fertilization was not important (Fig. 5C and 5D). Additional insight into sage grouse feeding choices is gained when other treatment combinations are examined (Fig. 5). When fertilizer was applied to ATW, sage grouse increased their propensity for feeding on ATW over ATV, even when ATV also was fertilized (Fig. SF). When ATV was tested against FATV, their relative consumption was not different. Thus, fertilization did not seem to increase use of ATV plants by grouse. In 1987 grouse consumed more FATW than ATW (f < 0.01). The lack of any feeding preference for FATW over ATW in 1988 could be a function of several factors. Birds could use morphological cues associated with the entire plant to select food plants within a population. Also, primary and secondary plant chemistry of FATW plants may have changed between the 1st and 2nd years of fertilizer response due to a natural diminution of any fertilizer effects or due to drought conditions during the 1987 growing season. Drought may have prevented FATW plants from expressing characters that elicit increased feeding activity by grouse. �17 Grouse feeding activity measured on fertilized plots may have increased slightly from 1987. In 1987 10% of the ATW on fertilized plots was fed on compared to 23% in 1988. The use of ATV and FATV, and ATW on control plots was about the same between 1987 and 1988. The apparent increased use in 1988 of FATW plants could be due to an overall increase in the numbers of birds using the NE quadrant of North Park in response to weather conditions. Winter 1986-87 was extremely mild with no permanent snow cover in most areas after mid-February. Permanent snow cover began accumulating in December 1987 and eventually completely covered many sagebrush stands, a situation more typical for North Park winters than winter 1986-87. These conditions generally cause birds to move to areas, like the NE quadrant, where windswept ridges and benches provide access to food. Grouse also may have learned that superior feeding sites existed in fertilized plots and increased their use of these areas. Sage grouse in the NE in winter 1987-88 made extensive use of areas north and south of the Walden Coal Company mine. The mine was closing and earth-moving activities during the winter caused dust to settle about the mine. Much dust was deposited north of the mine which, on sunny days, caused the snow to melt and thereby exposed ATW stands to grouse. These exposed areas were heavily used by sage grouse for feeding and nocturnal roost sites. It is not known if grouse used these sites traditionally or whether this use represents a learned response to habitat alteration. The observed survival distribution (Fig. 8) resembles that found by Kurzejeski et al. (1987), with more mortality occurring in spring and fall than at other times of year. Although survival of birds in the northeastern (NE) and northwestern (NW) quadrants of North Park was similar, most documented mortalities in the NW were due to hunter harvest, whereas in the NE most mortalities were caused by predators in spring. That harvest mortality is substantial in the NW is not surprising given hunting pressure for this part of North Park. High spring mortality rates for the NE is less easy to explain. The NE may contain more avian predators than the NW: there have been 2 active golden eagle nests in the NE and numerous corvids visit the county landfill in the NE portion of the Park. A total of 67% of the radios had to be censored. The assumption that the censoring mechanism was random may be violated. The center of gravity on poncho-mounted solar radio transmitters is such that if dropped, the radios fall face down (thereby covering the solar panels) more frequently than they fall face up. Thus, some mortalities may not be found because radios quit transmitting if they fall face (solar panels) down. Although radio-marked grouse did not use fertilized plots to any appreciable extent, grouse use of experimental blocks was detected from transect data. The occurrence of a drought during 1987 and heavy snow cover in winter 1987-88 made classifying grouse use and nonuse difficult at times. Drought caused many plants to abort leaves late in the 1987 growing season. Whole stems with leaves dropped sometimes looked similar to stems fed upon heavily by sage grouse, which can be fairly common when few other stems were exposed above the snow for grouse to feed upon. Such plants seemed to occur mostly on fertilized plots and were classified as not used by grouse unless 2 or more clipped petioles remained on the plant. �18 Within treatment variability during the digestion trials was greater in 1988 than in previous trials. One possible source of this variation was that 2 sources of birds were used, but this does not seem to be the cause because the data showed no consistent pattern with respect to bird source. A more probable source of variation was that insufficient time and resources were available to allow birds to fully acclimate to sagebrush treatments before measurements were collected. Between trials, birds were fed combinations of sagebrush treatments to help minimize acclimation problems. In previous trials birds were fed only ATW treatments and did not have to adapt to ATV diets during the digestion trials. All birds used in digestion trials eventually consumed the commercial ration. Use of this ration to maintain birds condition also could have caused digestibility of sagebrush treatments to be impaired. Sage grouse have proven to be difficult subjects for nutrition experiments. Both wild-caught and captive birds have lost weight rapidly when fed only sagebrush, so that prolonged diet acclimatization and sample collection periods are impractical. Field studies have suffered because only easily measured chemical parameters have been estimated and because plant chemical parameters are uncontrolled and confounded (Remington and Braun 1985, Welch et al. 1988). The problem of feeding native forage to captive grouse, while maintaining birds in good condition, has hampered others (e.g., Hill et al. 1968, Servello et al. 1987). A commonly used compromise for studying nutritional value of foods is to evaluate the relative digestibility of forage-ration mixtures. This approach sometimes produces absurd partial digestibility coefficients. for the forage portion of the diet, which limits this method's usefulness for estimating true digestibility of forages. If the research goals are to estimate the relative nutritive value of forages, this approach may be appropriate. LITERATURE CITED Hill, D. C., E. V. Evans, and H. G. Lumsden. 1968. Metabolizable energy of aspen flower buds for captive ruffed grouse. J. Wildl. Manage. 32:854858. Horwitz, W. Editor. 1980. Official of Official Analytical Chemists. C. 1018pp. Kurzejeski, E. W., L. D. Vangilder, turkey hens in North Missouri. methods of analysis of the Association Assoc. Off. Anal. Chern., Washington, D. and J. B. Lewis. 1987. Survival J. Wildl. Manage. 51:188-193. of wild Mould, E. D., and C. T. Robbins. 1981. Evaluation of detergent analysis in estimating nutritional value of browse. J. Wi1dl. Manage. 45:937-947. Pollock, K. H., S. R. Winterstein, C. M. Bunck, and P. D. Curtis. 1989. Survival analysis in telemetry studies: the staggered entry design. Wildl. Manage. 53:7-15. J. �19 Remington, T. E., and C. E. Braun. winter, North Park, Colorado. 1985. Sage grouse food selection J. Wildl. Manage. 49:1055-1061. in SAS Institute Inc. 1988. Additional SAS/STAT procedures, release 6.03. Tech. Rep. P-179. SAS Institute, Inc., Cary, N.C. 255pp. Servello, F. A., R. L. Kirkpatrick, and K. E. Webb, Jr. metabolizable energy in the diet of ruffed grouse. 51:560-567. SAS 1987. Predicting J. Wildl. Manage. Van Soest, P. J. 1963~. Use of detergents in the analysis of fibrous feeds. I. Preparation of fiber residues of low nitrogen content. J. Assoc. Off. Agric. Chem. 46:825-829. 1963Q. Use of detergents in the analysis of fibrous feeds. II. A rapid method for the determination of fiber and lignin. J. Assoc. Off. Agric. Chem. 46:829-835. 1982. Nutritional ecology of the ruminant. Corvallis, are. 374pp. a and B Books, Inc., Welch, B. L., and E. D. McArthur. 1986. Wintering mule deer preference 21 accessions of big sagebrush. Great Basin Nat. 46:281-286. _____ , J. C. Pederson, and R. L. Rodriguez. by sage grouse. Prepared by, 1988. Great Basin Nat. 48:274-279. ~orrinB.~ Graduate Research Assistant Approved by: Clait E. Braun Selection for of big sagebrush ��Colorado Division Wildlife Research April 1989 of Wildlife Report 21 JOB PROGRESS REPORT State of: Colorado Project: W-152-R Upland Work Plan: 3__ Job Title: Response Period Covered: Author: Personnel: Job Bird Research 17 of Selected 01 January through Avifauna to Fire in the Big Sagebrush 31 December Type 1988 Lee A. Benson C. E. Braun, C. Gefroh, C. Poley, Colorado L. A. Benson, Colorado State University Division of Wildlife; ABSTRACT The response of sage grouse (Centrocercus urophasianus) and passerine birds to fire was studied in Jackson and Moffat counties, Colorado. Lek counts were conducted during the breeding season. Radio-marked sage grouse were located during spring and summer months. Average daily spring movements were 0.8-0.9 km at all leks. Few locations of radio-marked sage grouse were obtained within burned areas during the breeding season. Movements to summering areas ranged from 1.1 to 28.5 km in North Park and averaged 1.6 km in Moffat County. Breeding bird surveys showed a large decrease in density of passerines at all burn sites. ��23 RESPONSE OF SELECTED AVIFAUNA TO FIRE IN THE BIG SAGEBRUSH TYPE Lee A. Benson INTRODUCTION Sagebrush (Artemisia ~.) dominates major portions of the western United States. Reports of total area covered by sagebrush vary from 35 million ha (Schroeder and Sturges 1975) to 60 million ha (Beetle 1960). More than 10% of all sagebrush lands have been altered by man (Braun et al. 1976). Among the methods used, fire is becoming increasingly more attractive as a management tool for reducing sagebrush (Frandsen 1985). This study was initiated as additional information is needed on the impacts of fire on wildlife so that any impacts can be more fully considered in management of the sagebrush type. P. N. OBJECTIVES l. Review 2. Capture 6 to 10 male sage grouse per lek and equip with poncho-mounted tail-clip transmitters. 3. Locate and flush birds at spring feeding/loafing 4. Obtain 5. Monitor 6. Establish 7. Measure vegetation structure and composition areas and at sage grouse use sites. literature lek counts pertaining to the impacts of burning on avian species. or sites. (minimum of 3) from study area leks. post-breeding transects movements of radio-marked and conduct breeding sage grouse. bird surveys at study areas. on treated and untreated STUDY AREAS Four areas were chosen for study. Three areas, Deer Creek, Perdiz, and Fish Hatchery leks were in North Park, Colorado. Another site, Thornburg Well, was in northwestern Colorado, approximately 8 km west of Maybell, in Moffat County. The Thornburg Well and Perdiz sites were burned by wildfire in 1987 and were approximately 1200 and 120 ha in size, respectively. The Deer Creek study area was burned by prescribed fire in fall 1987. Sagebrush at the wildfire sites has been reduced by nearly 100%. Some small areas of sagebrush survived within the Thornburg Well burns. The Deer Creek prescribed burn removed approximately 50-70% of the sagebrush cover in a 38 ha area. A more detailed description of study sites will be provided in later progress reports. �24 METHODS Sage Grouse Capture and Radio-marking.--Sage grouse were captured at night using a spotlight and a long-handled net on or near leks (Giesen et al. 1982). Birds were banded with serially numbered aluminum leg bands and plastic bandettes color coded by year. Age, sex, weight, and primary molt were recorded for each bird captured. Thirty-seven sage grouse were fitted with either poncho (Amstrup 1980) or tail-clip (Bray and Corner 1972) radio transmitters obtained from Wildlife Materials (Carbondale, IL), Telemetry Systems (Mequon, WI), and Advanced Telemetry Systems (Isanti, MN). Radio package weights ranged from 19.0 to 36.6 g and represented 0.7-1.4% of male body weights and 1.2-1.7% of female body weights. Relocations.--Radio-marked sage grouse were relocated on spring ranges from 14 April to 6 June. Birds were flushed and the location was marked to facilitate habitat measurements. Group size and flushing distance were also noted. An effort was made to flush all birds in the immediate area. Locations were plotted on 7.S-minute U.S.G.S. topographic maps. UTM map coordinates were obtained and used for distance calculations. Radio-marked sage grouse in North Park were relocated at approximately weekly intervals from June through September. Four attempts were made to locate radio-marked sage grouse in Moffat County resulting in a limited sample size for the Thornburg Well Lek. Average daily spring movements of sage grouse were obtained for 29 male sage grouse during the breeding season. Nineteen sage grouse had active radios during the summer months. Lek Counts.--Counts of male and female sage grouse were conducted between S April and 23 May. Birds present on leks were counted 3-S times during a lS-20 minute interval during each lek visit. Counts occurred within 1 hour of sunrise and were made from a distance of 30-1000 m depending upon weather, access, and observer preference. Breeding Bird Surveys Transects for breeding bird surveys were established at the Deer Creek, Perdiz, and Thornburg Well study sites. Transects varied in length from 4S0 to 1000 m with lengths varying because of features of the habitats to be sampled. Width of the transect was 140 m. Transects were marked at SO-m intervals and counts were conducted between 27 April and 21 June. Counts started O.S hour before sunrise and were completed within 2 hours of sunrise. A grid form was used to plot the estimated distance of birds from the transect. Singing males and non-singing individuals were recorded. Calculation of species diversity, evenness, and richness followed Wiens and Rotenberry (1981). Only singing males were used for calculation of birds per 40 ha, re1acive abundance, species diversity, evenness, and richness on all transects. Counts were averaged and then grouped by burn, burn edge, and unburned. These values were then converted to birds per 40 ha. The only exception was the unequal �25 length burn transects at the Deer Creek site. birds per 40 ha and then averaged. These values were converted to Habitat Measurements , Vegetation measurements were obtained from sage grouse spring feeding/loafing sites, a limited sample of random sites, and from 10-11 plots within each burn. Measurements were taken using Canfield's (1941) line-intercept technique and a modified Daubenmire (1968) plot. Two 10-m lines were measured at each location. Lines were oriented north-south and east-west centered over sage grouse flush locations or at random locations. Percent shrubs, forbs, and grasses were estimated to the nearest 5%, or if greater than 5%, at 20 0.5-m2 plots (lO/line at l-m intervals). Percentages less than 5% were estimated to the nearest 1%. Canfield's technique was used to measure the canopy and subcanopy while the 0.5-m2 plots were used to examine ground cover at or just above the soil surface. Measurements were summarized for male sage grouse locations and 31 burn plots within the 3 burns. Percent sagebrush was derived from line transect data. Percent shrub values were derived from 0.5m2 plots and included all shrubs and half shrubs. RESULTS AND DISCUSSION t Sage Grouse Lek Counts Lek counts at all study sites were similar to counts of past years (Table 1). Trends over the past 10 years suggest that sage grouse populations in North Park were low in 1988. systematic counts at Thornburg Well Lek had not been conducted for 6 of 11 years since initial location making assessment difficult. However, the trend also appears to be down. Counts in post-burn years should provide a clearer picture of population levels following fire. Sage Grouse Relocations Thirty-seven sage grouse were captured between 17 April and 11 May. Eleven adult and yearling male sage grouse (8 and 3, respectively) were radio-marked at Fish hatchery, 11 (7 and 4) at Deer Creek, 4 (3 and 1) at Perdiz, and 8 (7 and 1) at Thornburg Well. Radio-marked sage grouse were relocated on spring use sites from 14 April to 6 June for a total of 196 locations. Based on 75 relocations, average daily movements of radio-marked male sage grouse at the Deer Creek study site were 0.9 km (0.2-1.8 km). While several grouse were relocated near the burn edge, only 1 radio-marked sage grouse was located within the burn (Fig. 1). Average daily movements at the Fish Hatchery site (Fig. 2) were 0.9 km with a range of 0.1-2.2 km (n - 67). A small sample of relocations was obtained for the Perdiz study site. The average daily movement at Perdiz was 1.0 km (0.71.5 km) (Fig. 3). Average daily movements of radio-marked male sage grouse at the Thornburg Well site (Fig. 4) were 0.8 km (0.1-1.8) (n - 41). Four radio-marked male sage grouse at Thornburg Well were observed within the burn early in the breeding season (14 Apr). These birds were observed within small patches of unburned sagebrush. �26 Table 1. 1988. Sage grouse lek counts, Jackson and Moffat counties, April-May, High count Males Females N counts Dates of high count Males Females Peak male counts 1987 1986 1985 1984 1983 1982 1981 1980 1979 1978 1977 1976 1975 1974 1973 Deer Creekb Fish Hatchery (contro1)b 18 13 36 4 13 2 20 15 4 5 5 5 11 May 29 Apr 29 Apr 22 Apr 23 21 45 14 47 66 52 28 43 41 31 36 27 11 37 35 32 26 16 63 50 67 78 82 97 64 81 69 62 67 Perdizb 14 May 22 Apr Thornburg Well 25 Apr 5 Apr 16 6 10 8 21 27 23 8 16c 17a 15a Sa NC 8a 8a 20b 28b 3Sb 32b 36b,c aNo systematic counts, NC - no count. bSystematic counts. cYear of initial location. Radio-marked sage grouse were relocated on summer ranges from June through September. Most marked sage grouse in North Park moved to (or adjacent to) low lying wet meadow areas. Average distances of individual sage grouse relative to 1ek areas were: Deer Creek (n - 5) Fish Hatchery (n - 8) Perdiz en - 3) Thornburg Well (n = 3) 2.4 14.9 4.0 1.6 km km km km (1.1-7.2) (8.7-28.5) (3.7-4.1) (1.5-1.7) Long distance movements were observed at the Fish Hatchery study site. birds from this 1ek were followed to an area 2.4 km northwest of Rand, Two �> \: 1- ••••. ~ "" , 19 "" \. \. "----' , ~' " u u \~ "~~.j~ I ••,> ~.• ~.•o ~~~ o ...,. \ \ \ " ... ~ 27 ,-' \\ ')~ R7Bv)\" •.•. ~ v. " ~,. '\. , ') ~"" ~. \ -/. f ~ ~~ ~~ ~ " , ,.,. 8'''.5 ", '. {-.fa. •· ..f· ,...,.~ ,. \ D r/ t .. '. ... , ,..~ ,,'11';" ¢I.,. . '71-- I t .' ." ."\ .. ' \.' . "',\ " . .•.... .-..., "~ ,.j ' .'11\ '. '~~ \\ ' " --~"~-'f-~~~~~~~~--~~--~~--~~~~ __ -J'-"--~~-'r~~' 5,.•. " d ... "\\ \ ,I J • ,. __ • seu. ••• ){j~~<r_,- ,__ ";_._";..":.L._.J_. 7Wir _ ~ \' Fig. 1. Male sage grouse use sites (n = 80), Deer Creek study area, Jackson County, Colorado, spring 1988. Hatched outline represents proposed study area. Dotted line is approximate location of 1987 controlled burn. �28 4 -- ,..___ - ,.- .18 -lOr"",..., "> ..» I , ,1 16 --.. ~_..: •• r- •.••~ , i _, ~ .~, tlO' .....--, J_~ =.. ~\/) ',:> \II~ " ..-r: /_.' ,f ~ ". l8,t \ ":" ~ 1.,.. I j. II .... _ "02 - 'l!~ •••• ! " ",_I~I~" '\ ( --) -: .../') r Fig. 2. Male sage grouse use sites (£ = 67), Fish Hatchery study area, North Park, Colorado, spring 1988. Hatched outline represents proposed study area. �29 . \ _-:~ l .. ......~ .....:. .: '. •••IfJ1S 6.14 <') ,l ,. , . .,' ..J __,. - "",5 _ .' . J:. ; ~'. . I,. '. ," / I /i \ \ ( •.•.~~,.. .... : ....•.....•• ••••• I ~ •• •• , _..I' 17'.~,'-.:.•............ ..•••.....• ) ~- .: Fig. 3. Sage grouse use sites (Q = 12), Perdiz study area, Jackson County, Colorado, spring 1988. Hatched outline represents proposed study area. Line with XIS is approximate outline of 1987 wildfire. �, « t \ t fig. 4. Male sage grouse use sites (~= 37), Thornburg Well study area, Moffat County, Colorado, spring 1988. Line with XIS is approximate west edge of the 1987 wildfire. Hatched outline represents proposed study area. �31 Colorado, a distance of 26 km. One of these birds moved east 4.6 km and was observed in a flock with radio-marked sage grouse from the Deer Creek Lek. This bird was shot during the 1988 grouse hunting season. Only 1 additional radio-marked bird was recovered during the open season. Sage grouse in North Park were not observed in burns during the summer. Sage grouse at the Thornburg Well site did not exhibit a similar summer movement pattern. Radio-marked grouse were observed over summer on 4 occasions. Male sage grouse were observed either in the burn or in unburned areas of sagebrush within the burn on 3 different dates during June and July. One successful nesting hen was observed in a brood flock adjacent to the burn on 2 dates. This hen was predated (raptor) and her radio was recovered on 19 August. The other radio-marked female (also successful) was located from the air on 17 June approximately 3 km northwest of the lek area and 2 km south of the Yampa River valley. No locations were obtained after this date for this hen. Passerines r Breeding Bird Survey.--Breeding bird surveys were conducted between 27 April and 21 June. Transects at the Thornburg Well study site were counted 4 times between 27 April and 20 May. Transects at the Deer Creek study site were counted 4 times between 11 May and 10 June while those at the Perdiz study site were counted 5 times between 6 May and 21 June (Tables 2-4). D • Table 2. Birds (total) observed during 4 surveys of transects at the Deer Creek study site, Jackson County, Colorado, May-June 1988. Burned Unburned Species 1 2 3 Brewer's sparrow Vesper sparrow Sage thrasher Horned lark Green-tailed towhee Brewer's blackbird Mountain bluebird 11 9 3 1 3 3 4 0 4 2 0 15 16 1 4 5 0 0 0 0 0 Totals 27 41 13 I ~ 4 8 15 1 16 0 1 2 43 �32 Table 3. Birds (total) observed during 5 surveys of transects at the Perdiz study site, Jackson County, Colorado, May-June 1988. Unburned Species 1 Vesper sparrow Brewer's sparrow Sage thrasher Green-tailed towhee Horned lark Brewer's blackbird Mountain bluebird Barn swallow 8 70 7 3 Totals Edge 3 2 9 86 7 6 1 0 Burned 4 5 2 1 17 8 0 10 1 0 0 0 1 0 1 0 0 2 0 0 0 11 9 0 0 90 112 38 22 3 0 0 6 5 2 0 14 , , Table 4. Birds (total) observed during 4 surveys of transects at the Thornburg Well study site, Moffat County, Colorado, April-May 1988. Unburned Species 2 1 Vesper sparrow Brewer's sparrow Sage thrasher Horned lark Green-tailed towhee Sage thrasher Western meadowlark Lark sparrow Lark bunting 23 Totals Edge 3 15 7 Burned 4 5 0 0 0 \ 3 ~ 4 7 11 0 18 13 10 0 2 2 5 6 0 0 7 1 1 0 9 0 0 0 3 0 3 3 0 0 0 0 2 54 52 34 11 2 0 1 The most obvious finding was a substantial reduction in birds per 40.5 ha on burned transects in comparison with unburned transects (Table 5). At Deer Creek, birds per 40.5 ha were 40 in the unburned area and 18 in the burned area, a difference of 56%. At Perdiz, this value varied from 39 in unburned transects to 7 for the edge transect to 4 birds/40.5 ha in the burn. Data from Thornburg Well show a similar pattern of decreased density within the burn. 0 0 0 1 0 �33 Table 5. Species diversity, evenness, richness, and density on breeding bird transects in Jackson and Moffat counties, Colorado, Spring, 1988. Deer Creek Burned Unburned Species Diversity Evenness Richness Birds/40.5 ha 2.96 0.84 5.00 40.00 3.52 0.91 5.00 18.00 Unburned Perdiz Edge Burn 1.74 0.76 4.00 39.00 2.90 0.98 3.00 7.00 1.00 1.00 1.00 4.00 Thornburg Well Unburned Edge 4.00 0.84 6.00 48.00 3.44 0.85 5.00 32.00 Burn 3.44 0.87 5.00 25.00 Relative abundance (Table 6) varied markedly between burn and unburned areas. Vesper sparrows (Spizella breweri), and green-tailed towhees (Pipilo chlorurus) had lower relative abundances between burned and unburned transects. Relative abundance and density of horned larks (Eremophila alpestris) were greater in burned transects at all study sites. Species diversity (Table 5) was greater within the burn transects at Deer Creek but was lower at the wildfire sites. r t Table 6. Relative abundance (X) of breeding birds at study sites in Jackson and Moffat counties, Colorado, Spring, 1988. Deer Creek Unburned Burned Vesper sparrow Brewer's sparrow Sage thrasher Green-tailed towhee Horned lark Sage sparrow Lark sparrow Western meadowlark NP = 29 48 2 12 9 NP NP NP 28 28 3 6 35 NP NP NP Unburned 13 74 4 9 NP NP NP NP Perdiz Edge NP 29 29 NP 42 NP NP NP Burn NP NP NP NP 100 NP NP NP Thornburg Well Edge Unburned 40 20 12 4 NP 17 NP 7 12 12 43 6 NP 27 NP NP Burn 8 NP 23 NP 42 23 4 NP not present. Large differences were observed between transects in burned versus unburned areas at the 2 wildfire sites. Differences at the controlled burn site were less distinct. Larger numbers and species of breeding birds were observed during later counts at the wildfire study sites. This appeared to be due to the transition from mostly bare ground to a partial grass cover. Habitat Measurements A total of 177 locations was measured for habitat parameters at all study sites (Table 7). Averages for most variables appear to be within the ranges previously reported for North Park (Schoenberg 1982, Hernandez 1988). The percentage of sagebrush was somewhat lower because of some locations within burns. �34 Table 7. Vegetative parameters at sage grouse use sites in Jackson and Moffat counties, Colorado, 1988. Deer Creek (n - 59) Sagebrush Livea Fish Hatchery (n - 41) Thornburg Well (n - 20) 2.1 (0.4-5.0) 0.5 (0-1.8) 28.2 (3.3-50.9) 1.5 (0.8-2.8) 0.4 (0.2-1.0) 27.4 (4.2-44.2) 1.4 (0.4-2.3) 0.3 (0-1.0) 27.2 (7.9-44.8) Ave height, cm Ave width, cm Ave length, cm 34.3 (17.0-72.2) 43.9 (17.2-84.4) 35.7 (11.9-65.3) 36.4 (18.1-56.1) 50.6 (16.8-73.9) 42.7 (16.1-61.0) 50.6 (30.8-77.0) 60.5 (38.5-98.8) 51.9 (33.2-88.1) Ave space, cmb,c 75.0 (29.9-321.8) 85.3 (36.5-175.6) 99.9 (53.0-240.9) Ave shrub, %d Ave forb, %d Ave grass, %d 9.3 (0.1-21.0) 7.0 (0-24.4) 13.0 (3.4-73.2) 13.0 (5.4-24.4) 5.5 (0.5-20.6) 7.4 (2.2-24.0) Dead" Pe r c errtf 7.9 (3.2-14.2) 2.5 (0-7.2) 6.4 (3.5-12.1) , 1 aSagebrush p1ants/m2. bLine-transect data. cDistance between sagebrush plants. dDerived from 0.5-m2 plots. Vegetation measurements for burn sites varied (Table 8). Burns were characterized by a lack of sagebrush and low percentages of grass and forbs. Broom snakeweed (Gutierrezia sarothrae) and rabbitbrush (Chrysothamnus §£Q.) were the predominate shrubs within the burns. Table 8. Habitat parameters on burn plots in Jackson and Moffat counties, Colorado, 1988. Sagebrush Livea Dead" Pe rc errt" Ave shrub, %c Ave forb, %c Ave grass, %c Deer Creek Perdiz Thornburg Well 3 (1.9-5.3) 0.8 (0-4.8) 0.06 (0-0.2) 2.4 (2.0-3.2) 0.5 (0-2.2) 0.07 (0-0.3) 1.5 (0.4-2.2) 0.4 (0-3.0) 2.5 (0-10.4) 1.3 (0.2-3.4) 5.1 (2.3-7.3) 0.4 (0-1.9) 0.7 (0.1-1.9) 3.9 (1.6-5.8) 0.4 (0-1.5) 1.4 (0-3.8) 4.4 (2.8-7.1) o aSagebrush plants/m2. bLine-transect data. cDerived from 0.5-m2 plots. I C �35 Measurements of random locations and more complete habitat analysis will be provided in future progress reports. LITERATURE CITED Amstrup, S. C. 1980. 44:214-217. A radio collar for game birds. J. Wildl. Manage. Beetle, A. A. 1960. A study of sagebrush. The section (Tridentatae of Artemisia. Wyoming Agric. Exp. Stn. Bull. 368. Braun, C. E., M. F. Baker, R. L. Eng, J. S. Gashwiler, and M. H. Schroeder. 1976. Conservation committee report on effects of alteration of sagebrush communities on the associated avifauna. Wilson Bull. 88:165171. Bray, O. E., and G. W. Corner. 1972. A tail clip for attaching transmitters to birds. J. Wi1dl. Manage. 36:640-642. Canfield, R. H. 1941. Applications of the line interception method in sampling range vegetation. J. For. 39:388-394. Daubenmire, R. 266. 1968. Ecology of fire in grasslands. Adv. Ecol. Res. 5:209- Frandsen, O. A. 1985. Fire as a management tool in southeast Idaho - a case study. Pages 85-87 in K. Sanders and J. Durham, eds. Rangeland fire effects: a symposium. U.S. Bur. Land Manage., Boise, Idaho. Giesen, K. M., T. J. Schoenberg, and C. E. Braun. 1982. Methods for trapping sage grouse in Colorado. Wi1dl. Soc. Bull. 10:224-231. Hernandez, E. J. 1988. Response of selected avifauna to prescribed burning in the big sagebrush type. Colorado Div. Wildl. Job Progress Rep., Fed. Aid Proj. W-1S2-R. Apr:105-l38. Schroeder, M. H., and D. L. Sturges. 1975. The effect on the Brewer's sparrow of spraying big sagebrush. J. Range Manage. 28:294-297. Schoenberg, T. J. 1982. Sage grouse movements and habitat selection in North Park, Colorado. M.S. Thesis, Colorado State Univ., Fort Collins. 86 pp. Wiens, J. A., and J. T. Rotenberry. 1981. Habitat associations and community structure of birds in shrubsteppe environments. Eco1. Monogr. 5:21-41. Prepared by l...~C:~~.LL...L:::.~~:::::::===::_ Lee A. Benson Graduate Research Assistant Approved by C1ait E. Braun Wildlife Research Leader ��37 Colorado Division of Wildlife Wildlife Research Report April 1989 JOB PROGRESS REPORT State of: Colorado Project: W-152-R Avian Research Work Plan: 8__ : Job Job Title: Population Inventory and Habitat Use by Lesser Prairie-chickens in Southeast Colorado Period Covered: Author: 5__ 01 January 1988 through 31 December 1988 Kenneth M. Giesen Personnel: Clait Braun, Dave Clarkson, Ken Giesen, Rick Hoffman, Diane Picken, Jennie Slater, Chuck Wagner, Bryant Will, Colorado Division of Wildlife ABSTRACT Lek surveys were conducted on a 4l.4-km2 study site and surrounding area of the Comanche National Grasslands. Both lek numbers and total numbers of lesser prairie-chickens (Tympanuchus pallidicinctus) counted increased from previous years, suggesting the population increased in 1988. There was a positive correlation between male breeding density and number of active leks (I = 0.94) but not between male breeding density and average number of males/lek (I = 0.30). Experimental roadside lek surveys resulted in 77 to 100% of active leks being detected. Leks not detected were along the transect with the highest lek density. Thirty-eight prairie-chickens were trapped and banded with 8 males and 19 females being fitted with radio transmitters. Average home range was 158 ha. Hens dispersed 0.4 to 2.4 km from leks where marked to nest sites (R = 1.4 km). Average size of initial clutches was 11.2 eggs. Two hens attempted renests. Residual vegetation from 160 random transects on the study area was analyzed to quantify available habitat. Existing vegetation was measured ~t all nest sites, 51 grou~e_flus~ sites, and 51 paired random sites to document habitat preference. Nest sites hadtal1er vegetation than random sites while no apparent differences were detected between 7 habitat variables measured at grouse flush and random sites. ��39 POPULATION INVENTORY AND HABITAT USE BY LESSER PRAIRIE-CHICKENS IN SOUTHEAST COLORADO Kenneth M. Giesen Both distribution and populations of lesser prairie-chickens in North America have decreased> 90% from historic levels of the 1800's (Taylor and Guthery 1980). Although the exact historic distribution of lesser prairie-chickens is unknown, early reports (Bendire 1892, Judd 1905, Bent 1932, Baker 1953, Sands 1978) suggested they were abundant and widely distributed throughout their range. Aldrich (1963) indicated lesser prairie-chickens historically inhabited about 360,000 km2 in 5 states while recent estimates suggest a population of 50,000 birds on 125,000 km2 (Crawford 1980, Taylor and Guthery 1980, Johnsgard 1983). Although evidence suggests lesser prairie-chickens were historically peripheral in Colorado, they were thought to be common to abundant in 6 southeastern counties (Baca, Prowers, Bent, Kiowa, Lincoln, and Cheyenne), and peripheral in adjacent counties (Loeffler 1983). Recent surveys have documented breeding populations in Baca, Prowers, and Kiowa counties (Hoffman 1963, Loeffler 1983, Rash 1985, this study). Efforts to transplant lesser prairie-chickens into Lincoln county in 1968 apparently failed and the outcome of a 1988 transplant to Pueblo County is unknown. Because of apparent small population and restricted range, the lesser prairie-chicken is classified as a threatened species in Colorado. P. N. OBJECTIVES The objectives of this study are to evaluate lek surveys as indices to population trends, ascertain the accuracy of aerial and ground surveys in detecting leks, describe the seasonal floristic and structural characteristics of lesser prairie-chicken habitats in southeast Colorado, and contribute to preparation of a recovery plan for lesser prairie-chickens in Colorado. SEGMENT OBJECTIVES 1. Review pertinent literature applicable to the objectives of this study. 2a. Locate all active leks within a 41.4 km2 primary study area and obtain at least 1 count/week (Mar-May) of all males and females on each lek. 2b. Survey all historic leks in Baca County and obtain at least 1 count of males on each active lek. 3. Select 4 20-km long roadside listening transects within the range of lesser prairie-chickens in Baca County and test the ability of naive observers to detect active lesser prairie-chicken leks within 1.6 km of the transects. �40 4. Trap and band lesser prairie-chickens on active leks within the primary study area. Up to 20 will be marked with miniature radio transmitters to facilitate their periodic location. 5. Locate lesser prairie-chicken nests by following radio-marked Record clutch size, incubation period, and nest fate. 6. Locate radio-marked range. 7. Measure vegetative cover at grouse use and random sites. Height and canopy cover of shrubs, forbs, and grasses will be recorded. 8. Compile birds weekly data, analyze results, for estimates and prepare of movement annual progress hens. and home report. METHODS Field surveys were conducted on the Comanche National Grasslands and adjacent areas in eastern Baca County from March through June using binoculars, a parabolic microphone listening device, and a trained pointing dog to locate active lesser prairie-chicken leks. Leks known to be active in 1987 were surveyed as well as most known historic lek sites. Active leks were visited within 2 hours of sunrise to count grouse and classify them to sex. Lek density was defined as the number of active leks on the 41.4 km2 study area and breeding male density was the sum of the high counts of males on each lek on the study area expressed as male/km2. Two roadside transects were conducted by naive observers during the peak of lesser prairie-chicken breeding (19-20 Apr). A 3-minute listening stop was taken approximately every 1.6 km to listen for displaying grouse. Distance and direction to detected leks were estimated and plotted on a map. Routes began 15 minutes prior to sunrise and were completed within 2 hours. Cannon-nets and funnel traps (Giesen et al. 1982) were used to capture grouse on leks. Each captured grouse was marked with a numbered aluminum band and a unique combination of colored plastic bandettes. Miniature solar- or battery-powered transmitters (weight 18-24 g) were attached to all captured females and selected males using a poncho (Amstrup 1980). Radio-marked birds were located using a portable receiver and hand-held yagi antenna. Birds were approached on foot until they flushed. Vegetative structure and species composition were measured using line-intercept of canopy cover (Canfield 1941) and a range pole (Robel et al. 1970). Nomenclature follows Harrington (1964). Sand sagebrush (Artemisia filifolia) density was measured on 0.001 ha circular plots. The minimum convex polygon method (Mohr 1947) was used to calculate home range sizes. Study Area The primary study area was a 41.4 km2 (16 mi2) area of rangeland on or adjacent to Pasture lAE of the Comanche National Grasslands. Included were sections 21-28 and 33-36 of T34S, R44W and sections 1-4 of T35S, R44W. Approximately 1160 ha was privately owned and was rangeland except for a 16 ha milo (fallow in alternate years) field. The topography was rolling hills bisected by Murray Draw and Mitchell Draw. Elevation ranged from 1240 m on �41 the west to 1070 m on the east. Soils were predominately fine sands in the draws (U.S.D.A. Soil Conserv. Service). sandy loams with Topography, grazing, ana revegetation have resulted in a diverse vegetative community. Sand sagebrush, broom snakeweed (Gutierrezia sarothrae), and yucca (Yucca glauca) were the predominant shrubs. A variety of grasses occurred with sand dropseed (Sporobolus cryptandrus), 3-awn (Aristida longiseta), sideoats grama (Bouteloua curtipendula), and blue grama (~. gracilis) being most widespread. Seven habitat variables were measured in March-May 1986-87 to quantify existing cover (Table 1). Except for forbs, the height measurements were from residual vegetation. Table 1. 1986-87. Habitat characteristics of a 41.4 km2 lesser prairie-chicken study area, Baca County, Colorado, Location Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. 21, T34S, R44W 22, T34S, R44W 23, T34S, R44W 24, T34S, R44W 25, T34S, R44W 26, T34S, R44W 27, T34S, R44W 28, T34S, R44W 33, T34S, R44W 34, T34S, R44W 35, T34S, R44W 36, T34S, R44W 1, T35S, R44W 2, T35S, R44W 3, T35S, R44W 4, T35S, R44W Mean Heightdensity Bare ground Shrub Height ~cm2 Forb 40.5 44.6 40.0 33.6 31.5 31.0 29.2 29.8 35.5 36.6 22.2 33.8 28.1 31.1 42.9 32.8 3.3 3.8 3.6 3.1 4.6 4.5 1.5 1.7 3.2 4.7 5.2 1.9 2.0 4.5 3.6 6.0 6.0 27.1 22.5 16.9 13.9 17.2 6.6 7.4 11.0 15.5 12.0 4.4 9.7 9.9 17.4 11.2 0.28 0.90 1.16 1.46 0.87 1.58 0.32 0.79 1.67 1.18 0.97 0.78 1.33 0.57 1.07 0.78 81.2 59.9 65.4 76.1 86.7 70.4 55.2 84.5 81.9 72.0 34.6 3.6 13.0 0.98 Grass X Sand sagebrush Canopy cover Density 79.4 89.8 74.2 73.4 78.6 0 2360 4160 7480 2467 2840 2067 4266 2800 1560 2880 533 667 1520 1267 3080 0.0 7.1 10.0 5.4 3.1 4.6 0.6 3.0 5.1 2.6 3.5 0.2 0.0 0.9 1.9 1.5 75.4 2497 3.1 n.8 RESULTS AND DISCUSSION Lek Surveys A total of 185 counts of 26 active leks was obtained in Baca County between 18 March and 17 May 1988 (Table 2). In addition, 6 historic lek sites were surveyed and found to be inactive. A minimum of 202 males, 24 females, and 289 total birds was counted for an average 11.1 birds/active lek, up 18% from 1987. Several long-term active leks south of the Cimarron River were not surveyed in 1988. Summaries of lek count data since 1977 (when written records became available for analysis) indicate the dynamic nature of leks with many becoming inactive and others being established (Table 3). Fifteen of 57 leks (26%) active one or more years since 1977, were initially located in 1985-88 as a result of more search effort and possibly increasing lesser prairie-chicken populations. �42 Because numbers of grouse attending leks fluctuates during the breeding season, and survey timing and intensity varied each year, the data (Tables 2, 3) may not reflect actual population changes. Table 2. Lesser prairie-chicken lek count data, Baca County, 1988.4 Lek N counts 2 3 4 5 6 7 12 14 17 18 2S 27 28 33 35 39 40 86-1 86-3 87-1 87-2 87-4 87-5 88-1 88-2 88-3 18 IS 16 24 9 6 1 2 3 8 1 7 23 9 1 2 2 16 1 1 1 11 2 2 3 1 Total 185 Mean Count period 18 18 18 18 01 01 31 07 18 07 18 06 01 05 18 30 10 07 21 Mar-17 Mar-30 Mar-03 Mar-17 Apr-OS Apr-OS 10 May Mar-07 Apr-27 Mar-05 10 Apr Apr-20 Mar-13 Apr-OS 07 Apr Apr-05 May-06 Mar-10 28 Apr 23 Apr 04 May Mar-06 Apr-19 May-28 Apr-06 06 May May Apr May May May May May Apr May Apr May May Apr May May Males High count Females Tota1sb 12 11 6 23 6 12 2 6 11 11 5 7 20 11 16 7 3 1 1 4 12 2 15 6 5 9 2 4 3 5 1 14 4 3 6 8 202 24 1 1 1 5 2 15 13 9 25 6 16 4 13 14 13 8 7 25 15+ 16 14 6 3 9 May Apr Apr May 9.2 2.0 289 11.1 aLeks 8, 13, 21, 32, 38, 86-2, were surveyed and no birds observed. bIncludes males, females, and birds not classified to sex. Analyses of 1ek surveys and 1ek count data (Table 4) indicates a strong positive correlation between males breeding density and number of active leks (£ ~ 0.94) but not bet~een male breeding density and average lek size (£ 0.30). If the high count of males on leks was a constant proportion of the total population, lek density is a better index to population changes than average lek size. These data support results of prairie grouse population �43 Table 3. Lek High counts of male lesser prairie-chickens, Baca, COU'lty,1977-88. 1977 1978 4 18 8 9 24 22 15 1 0 5 14 6 8 NC 15 11 NC HC NC NC 5 13 11 11 0 4 14 HC 0 4 13 16 6 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 86-1 86-2 86-3 87-1 ' 87-2 87-3 87-4 87-5 88-1 88-2 88-3 0 7 0 7 17 17 16 2 3 3 5 aHo bLek b 1979.- 1980 HCa 10 2 7 12 15 11 0 0 0 NC 7 12 10 12 NC 3 NC HC 2 1 6 17 NC count. not yet located. 0 1 17 12 15 14 11 0 0 0 0 17 8 9 9 0 0 9 0 0 0 4 19 0 3 9 7 7 1981 Year 1982 1983 0 6 15 7 16 14 6 0 0 0 0 20 8 8 0 3 12 7 29 10 9 0 0 0 0 14 7 6 0 0 0 0 0 9 0 0 0 3 30 0 6 4 4 7 4 18 14 6 8 6 0 10 0 0 0 0 33 0 11 2 4 4 0 10 17 0 6 0 10 12 0 12 11 9 26 14 8 0 0 0 0 16 5 12 0 0 0 9 0 0 0 0 23 0 3 2 3 4 0 0 13 0 0 0 16 7 12 7 10 4 1984 1985 1986 1987 1988 0 9 7 7 23 18 7 0 0 0 7 7 0 18 6 5 0 0 HC 16 2 0 17 6 9 NC NC NC NC 5 0 10 NC NC 4 10 NC HC 0 HC 2 HC 2 0 0 12 0 0 2 0 0 0 10 0 12 2 11 8 3 0 5 HC 9 3 3 18 3 8 HC 12 11 6 23 6 12 0 0 0 18 0 0 0 11 0 0 5 9 0 0 0 0 11 0 0 2 5 0 0 0 0 21 0 2 3 0 0 0 6 11 0 0 0 21 0 10 8 18 5 3 14 0 16 0 0 0 4 10 2 2 7 5 0 0 13 0 12 3 9 7 7 7 7 3 4 4 0 0 1 15 6 7 0 0 NC 0 HC 4 0 8 NC HC 7 13 HC HC 0 HC 0 HC 6 0 0 17 0 HC 9 0 8 HC 18 0 18 7 0 9 0 10 NC 5 NC 0 11 5 8 0 0 0 7 5 HC HC HC 2 0 6 NC NC 11 11 HC NC 0 HC HC HC 5 HC 720 HC HC HC 0 11 HC 16 NC NC 0 7 6 HC HC HC NC NC HC 12 0 0 0 0 HC 9 4 3 5 0 �44 surveys in other states (Cannon and Knopf 1981, Martin and Knopf 1981). These results suggest lesser prairie-chicken population changes are reflected in the total number of active leks rather than the average number of birds/1ek. Thus, inventory methodology should incorporate plans to document annual status (active/inactive) of historic leks and efforts to search for additional leks. Table 4. Lek count trends of lesser prairie-chickens study area, Baca County, Colorado, 1980-88. N N Year leks males ~ ma1es/1ek 1980 1981 1982 1983 1984 1985 1986 1987 1988 6 6 6 6 4 5 7 8 9 59 55 59 65 46 46 75 74 100 9.8 9.2 9.8 10.8 11.5 9.2 10.7 9.2 11.1 on a 41.4-km2 (16 mi2) Breeding density (ma1es/km2) 1.42 1.33 1.42 1.57 1.11 1.11 1.81 1.79 2.42 Lek Transects Lek survey routes are used by many state wildlife agencies to monitor trends in prairie grouse populations. Although lek density correlates well with male breeding density, there have been no studies to evaluate the accuracy or precision of transects in detecting active leks. Surveys of 8 transects in 1987 resulted in only 40.7% of active leks being detected. Weather and observer bias were detected suggesting that 1ek survey rates may not be useful in monitoring lesser prairie-chicken populations unless the count variability can be controlled. In 1988, observers detected 76.9 to 100% of active leks within 1.6 km of the transect (Table 5). The increase in detection rate was attributed to favorable weather conditions (no wind) and conducting surveys during the peak of hen attendance when display activity was highest. All active leks were detected on the transect with low grouse density but 7.7 to 23.1% were missed where grouse densities were higher. At high lek densities, it was possible to detect 3 or more leks from some listening stops. In those situations, the larger or closest leks appeared to overwhelm the display sounds from smaller or farther leks, thus causing them to be missed. Naive observers (having no knowledge of lek locations) were used to evaluate survey accuracy in these experiments. For management purposes, the observers would most likely be the District Wildlife Manager or Area Biologist who would know the location of historic leks, thus needing only to verify their current status (active/inactive) and search for newly established leks. This should increase the accuracy of the survey routes. �45 Table 5. Leks detected County, Colorado, 1988. Transect 1 2 Length during experimental aNumber of active leks within Trapping transects in Baca n leks detected Observer Observer 1 (km) 19.2 19.2 roadside 13 4 12 4 2 10 4 1.6 km of transects. and Banding A total of 33 lesser prairie-chickens (19 males, 14 females) was trapped on 5 of 9 active leks within the primary study area. Five females were trapped on 2 leks adjacent to the study area. Most females (16 of 19, 84.2%) were captured between 13 and 23 April which corresponded to the peak of hen attendance at leks. Five of 9 hens captured prior to 18 April were adults compared to 1 of 10 hens captured after 18 April suggesting that adult hens breed earlier than yearling hens. All captured prairie-chickens were marked with a serially numbered aluminum band and unique combinations of colored bands to facilitate future identification. Eight males and all 19 hens were fitted with poncho-mounted miniature radio transmitters (18-24 g, 2.6-3.3% of grouse weight) to facilitate their periodic relocation. Although the transmitters were not thought to affect the daily activity patterns or movements of grouse, at least 10 radio-marked grouse (2 males, 8 females) were killed by predators within 30 days. Radio contact was lost with 5 other hens because of radio-failure or predation. Increased predation due to radio-marking has been reported for other birds (Herzog 1979, Warner and Etter 1983, Hines and Zwickel 1985, Marks and Marks 1987). Nesting Fates of 19 hens were ascertained using radio-telemetry techniques. Radio signals from 7 hens were lost before their nests were located. It was most likely that radio failure or undetected predation occurred although long range (> 15 km) dispersal may have occurred. Radio signals were not detected from these hens in subsequent searches through October. Six hens were killed by predators prior to incubation and 4 hens were depredated during incubation prior to hatch. Of 8 nests located (including 2 renests), none was successful. Causes of high predation on hens and nests were unknown as nests were visited initially at the estimated onset of incubation to ascertain clutch size and subsequently when hen mortality or nest depredation was suspected. The average distance from capture site on leks to first nests was 1442 m (n 6) with 2 hens nesting closer to another lek. The average distance between initial clutches and renests was 700 m. Average clutch size of 4 complete first clutches was 11.2 eggs; the 2 renests contained 5 and 10 eggs. �46 Hens selected nest sites which had greater cover than surrounding areas. Forb height, grass height, and height-density were greater at nest sites than random sites (Table 6). Average shrub height, sandsage density, and canopy cover were also higher ~t nest sites but differences were not significant (f > 0.05). Because nesting occurs early in the season before significant vegetative growth, it may be beneficial to manage rangeland to increase the height and density of residual grass cover. Nest site measurements suggested that hens selected for clumps of tall grasses (> 30 cm) and height density measurements of > 2.8 dm. The low recorded nest success observed may indicate that high quality nesting cover may be limiting in the study area. Table 6. Habitat variables at lesser prairie-chicken nest sites, 10-m nest transects, and random 10'm transects in Baca County, Colorado, 1986-88. (Sample sizes in parentheses; letters within rows indicate a [~ < 0.05] difference for that variable). Variable Nest site Shrub height, ~ Forb height, ~ Grass height, ~ Height-density, dm Sandsage density, plants/ha Sandsage canopy cover, % Bare ground, % (16) (16) (16) (16) Nest transect 42.9 18.2A 31.4A 2.88AB (16) (16) (16) (16) (16) (16) (16) 34.4 14.9B 25.5B 1.86A 3292 6.4 73.9 Random transect (141) (150) (151) (158) (158) (158) (158) 34.4 3.6A3 13.3AB 1.18B 2524 3.0 75.2 Home Range Size Home range sizes were measured for 5 males and 5 females which were observed for more than 30 days (Table 7). Average home range size was 158 ± 145 ha with no difference in mean home range size between males and females. Home range sizes of males included their lek site while female home ranges (after breeding) were spatially separate from leks. Table 7. Home range size of radio-marked County, Colorado, 1988. lesser prairie-chickens in Baca Band Time interval Home range size (ha) 360 361 362 366 368 369 373 381 390 393 Age 2+ 2+ 1+ 1+ 2+ 2+ 2+ 1+ 1+ 1+ Sex M F M M F M F F M F 7 8 8 12 IS 15 15 19 22 22 Apr-22 Apr-23 Apr-ll Apr-27 Apr-25 Apr- 3 Apr-12 Apr-25 Apr-14 Apr- 1 May Aug Oct Oct May Jul Sep May Jun Jun 80 227 258 130 32 374 392 7 26 57 �47 Habitat Preference Habitat preference was investigated by comparing vegetative measurements at grouse flush sites and adjacent random sites. Preliminary analysis indicated no differences (~ > 0.05) in mean values for the 7 habitat variables measured at flush and random sites (Table 8). The height-density and sandsage canopy cover variables had different (~ < 0.05) distribution functions between the grouse flush sites and random sites suggesting that the grouse may have been avoiding the extreme values of these 2 habitat components. Table 8. Habitat variables at lesser prairie-chicken flush and paired random sites in Saca County, Colorado, 1987-88. Mean Variable Grouse-flush site Random site 37.8 13.3 16.6 1.89 5189 9.95 85.5 35.1 12.9 15.2 1.51 3~3 5.15 85.6 Shrub height, cm Forb height, cm Grass height, cm Height-density, dm Sandsage density, plants/ha Sandsage canopy cover, X Bare ground, X awilcoxin rank-sum test, Ho: !1 = f > Prob f > Ilia 0.1829 0.3661 0.5183 0.0727 0.1405 0.0783 0.8513 0.2829 0.7717 0.5043 0.0478 0.0789 0.0145 0.9619 !2' There may be several reasons I failed to detect habitat selection by lesser prairie-chickens. The grouse flush and paired random sites were relatively close (293 ± 108 m, range 55-541 m) and measured on the same day. If habitat was fairly uniform over large areas there would be little need for selection at the macro level. However, measurements of flush and random sites indicated high variation for each habitat component. Because of small sample sizes each month, the data were pooled. Only grass height and forb height increased throughout the season and the differences between flush and random sites remained constant. Because the study area contained the highest known density of lesser prairie-chickens in Colorado, all of the habitat may have been equally good. Sampling in areas with different grouse densities may provide better insight into habitat preference. Furthermore, habitat preference may be strongest when some components may be in short supply at critical times of the year (i.e., nesting cover, winter habitat). Summer habitat measurements may not detect these differences. Additional sampling should be done at other seasons. LITERATURE CITED Aldrich, J. W. 1963. Geographic Wildl. Manage. 27:529-545. Amstrup, S. C. 1980. 44:214-217. orientation A radio-collar of American for game birds. Tetraonidae. J. Wildl. Manage. J. �48 Baker, M. F. 1953. Misc. Publ. 5. Prairie chickens of Kansas. 68pp. Univ. Kansas Mus. Nat. Hist. Bendire, C. E. 1892. ~ife histories of North American birds with special reference to their breeding habits and eggs. U.S. Nat1. Mus. Spec. Bull. 1. 446pp. Bent, A. C. 1932. Life histories of North America gallinaceous Natl. Mus. Bull. 162. 490pp. Canfield, R. H. 1941. range vegetation. birds. U.S. Application of the line intercept method in sampling J. For. 39:338-394. Cannon, R. W., and F. L. Knopf. prairie grouse populations. 1981. Lek numbers as a trend index to J. Wildl. Manage. 45:776-778. Crawford, J. A. 1980. Status, problems, and research needs of the lesser prairie chicken. Pages 1-7 in P. A. Vohs and F. L. Knopf, eds. Proc. Prairie Grouse Symp. Oklahoma State Univ., Stillwater. Giesen, K. M., T. J. Schoenberg, and C. E. Braun. 1982. Methods sage grouse in Colorado. Wildl. Soc. Bull. 10:224-231. Harrington, H. D. 1964. Manual of the plants of Colorado. Swallow Press, Inc., Chicago. 666pp. for trapping Sage Books, Herzog, P. W. 1979. Effects of radio-marking on behavior, movements, survival of spruce grouse. J. Wildl. Manage. 43:316-323. Hines, J. E., and F. C. Zwickel. 1985. Influence of radio packages blue grouse. J. Wildl. Manage. 49:1050-1054. Hoffman, D. M. 1963. The lesser prairie chicken in Colorado. Manage. 27:726-732. Johnsgard, P. A. 1983. Lincoln. 413pp. The grouse of the world. J. Univ. Nebraska and on young Wildl. Press, Judd, S. D. 1905. The grouse and wild turkeys of the United States and their economic values. U.S. Dep. Agric. Biol. Surv. Bull. 24. 55pp. Loeffler, C. 1983. The status and management of the lesser prairie chicken in Colorado. Unpubl. Rep., Colorado Div. Wildl., Colorado Springs. 9pp. Marks, J. S., and V. S. Marks. 1987. Influence of radio-collars of sharp-tailed grouse. J. Wildl. Manage. 51:468-471. on survival Martin, S. A., and F. L. Knopf. 1981. Aerial survey of greater prairie chicken leks. Wildl. Soc. Bull. 9:219-221. Mohr, C. O. 1947. Table of equivalent populations mammals. Am. Midi. Nat. 37:223-249. of North American small �49 Rash, M. T. 1985. Survey of the lesser prairie-chicken in Colorado, 3 April25 May 1985. Unpub1. Rep., Colorado Div. Wi1d1., Colorado Springs. 22pp. Robel, R. J., J. N. Briggs, J. J. Cebula, A. D. Dayton, and L. C. Hulbert. 1970. Relationships between visual obstruction measurements and weight of grassland vegetation. J. Range Manage. 23:295-297. Sands, J. L. 1978. Game bird studies. New Mexico Dep. Game and Fish Proj. Performance Rep., Proj. W-l04-R-19. Albuquerque. 5pp. Taylor, M. A., and F. S. Guthery. 1980. Fall-winter movements, ranges and habitat use of lesser prairie chickens. J. Wi1d1. Manage. 44:521-524. Warner, R. E., and S. L. Etter. 1983. Reproduction and survival of radiomarked hen ring-necked pheasants in Illinois. J. Wi1d1. Manage. 47:369-375. Prepared by _1iwd..=..==;.......!...rtJ . ~~=' ~ Kenneth M. Giesen Wildlife Researcher _ ��Colorado Division of Wildlife Wildlife Research Report April 1989 51 JOB FINAL REPORT State of: Colorado Project: W-152-R Work Plan: .... _9.... Job .... _8 .... Job Title: Food Selection and Nutritional Ecology of Blue Grouse During Winter Period Covered: Author: Upland Bird Research 01 July 1983 through 31 December 1988 T. E. Remington Personnel: C. E. Braun, S. F. Brinkman, R. W. Hoffman, T. E. Remington, M. L. Stevens, Colorado Division of Wildlife ABSTRACT Food use, food selection, and energy and nutrient use within foods by blue grouse (Dendragapus obscurus) were investigated. Douglas-fir needles (Pseudotsuga menziesii) were most used, most preferred, and the most nutritious needles. Lodgepole pine (Pinus contorta) and limber pine (f. flexilis) needles were also fed-upon by blue grouse. Blue grouse avoided monoterpene-treated chow but monoterpenes were not related to preferences among needle groups. The youngest needles from old (> 100 years) trees were most preferred and contained the most metabolizable energy and nitrogen. Energy and nutrients obtainable from different needle groups were a function of the initial nutrient or energy content, and more importantly the energy or nutrient costs of detoxifying the toxins within them. Monoterpenes and phenolic acids were important toxins but the primary toxins were apparently not identified. Six manuscripts were prepared for publication. Recommendations are presented for maintenance of blue grouse winter habitats. �52 RECOMMENDATIONS Blue grouse in Colorado are dependent on coniferous forests for food in winter. Consequently, logging within coniferous forests may impact blue grouse negatively. The results of this research suggest ways in which impacts of logging on blue grouse can be prevented or minimized. Recommendations are: 1. Cutting within high-elevation stands of Douglas-fir should be minimized. Needles of Douglas-fir are the most preferred, arguably the most used, and yield the greatest metabolizable energy and nitrogen of available conifers. 2. If high elevation (> 2500 m elevation) conifer stands must be cut, then a portion of the Douglas-fir should be left uncut. Douglas-fir most frequently used by blue grouse exceed 150 years of age while Douglas-fir less than 100 years old are seldom fed-upon. Therefore old, decadent trees should be left which will have the greatest value to blue grouse at the lowest sacrifice of merchantable timber. 3. Lodgepole pine needles are also valuable food resources for blue grouse, and lodgepole stands are frequently logged. Fortunately, most lodgepole stands within Colorado are large and blue grouse use only small portions of them. If cuts are to be large (> 50 hectares), impacts to blue grouse can be minimized by identifying (by searching for dropping accumulations), and leaving uncut, sections which contain evidence of winter occupancy by blue grouse. Scattered subalpine fir (Abies lasiocarpa) and/or Engelmann spruce (Picea en~elmanii) should also be left since blue grouse prefer to roost in these species (rather than lodgepole) and they loose less heat in them. 4. Attempts to characterize the quality of conifer needles as food for blue grouse by standard nutritional analyses are likely to lead to erroneous conclusions. Any nutritional assay must be validated by a bioassay, preferably with wild-captured birds. Palatability is an important parameter to assess in winter foods of blue grouse, and it can be evaluated only by observation or bioassay. �53 FOOD SELECTION AND NUTRITIONAL ECOLOGY OF BLUE GROUSE DURING VINTER Thomas E. Remington The results of this study have been prepared in a series of 6 papers. These manuscripts will be submitted for internal review and subsequent publication in technical journals. Publication will be supported through Work Plan 22, Job 1. The 6 manuscripts are: 1. Why don't blue grouse eat aspen in winter?; 2. Why do grouse have ceca: 3. Food habits and food selection of blue grouse during winter; 4. Temporal patterns 5. Metabolizable grouse; and 6. Costs of detoxification Submitted by ~ a test of the fiber digestion theory; of feeding by blue grouse during winter; energy and nitrogen content of conifer needles of secondary compounds t-- t. ~ Thomas E. RemingtOn Wildlife Researcher A to blue to blue grouse. ��Colorado Division of Wildlife Wildlife Research Report April 1989 55 JOB PROGRESS REPORT State of: Colorado Project: W-152-R Upland Bird Research Work Plan: 12 Job Title: Chronology of Breeding and Nesting Activities Relation to Timing of Spring Hunting Seasons Period Covered: Author: Job 01 January 15 through 31 December of Wild Turkeys in 1988 Richard W. Hoffman Personnel: C. E. Braun, R. W. Hoffman, R. L. Holder, and R. K. Mueckler, Colorado Division of Wildlife; E. N. Hall, Colorado State University ABSTRACT Gobbling and nesting activities of 52 radio-marked (10 subadult males, 3 subadult females, 39 adult females) Merriam's wild turkeys (Meleagris gallopavo merriami) were monitored in relation to timing of the spring hunting season in southeastern Colorado. Females moved 11.8 ± 5.7 km from wintering to breeding areas compared to movements of 8.7 ± 3.1 km for subadult males. Subadult males gobbled 62 times during 85 hours of morning (50 hrs) and evening (35 hrs) listening periods from one half hour before to one half hour after sunrise and sunset. Subadult males did not gobble during most morning (74%) and evening (97%) indices, but the tendency was to gobble more in the morning (1.2 gobblesjbird/hr) than evening (0.03 gobblesfbird/hr) and more on (0.93 gobblesjbird/hr) than off (0.56 gobblesjbird/hr) the roost. Subadult males gobbled most (1.7 gobblesjbird/hr) when only accompanied by hens. Eleven (31%) of 36 hens surviving into the nesting season were successful (hatched at least 1 egg). Seven hens initiated incubation prior to the end of the spring hunting season, 5 of which started the last week of the season. Twelve hens started incubation between 16 and 31 May and 4 hens started between 1 and 8 June. The peak period of incubation was 11-25 May; 16 hens (70%) initiated incubation during this period. The harvest survey indicated 3,819 spring hunters harvested 671 turkeys (18% success) and 1,225 fall hunters harvested 355 turkeys (29% success). Las Animas County was the leading harvest area. Public land supported 54% of the hunting pressure, but produced only 42 (spring) and 34% (fall) of the harvest. Hunter success was better on private (spring = 29%, fall = 56%) than public (spring = 14%, fall = 21%) land. The wing collection program sampled 74% of the spring harvest and 70% of the fall harvest. Merriam's dominated (> 90%) the harvest samples. Sixty six percent of the spring harvest of Merriam's were adults compared to 50% for Rio Grandes. The fall harvest (Merriam's only) was comprised of 39% juveniles. The poult to hen ratio was 1:1. ��57 CHRONOLOGY OF BREEDING AND NESTING ACTIVITIES OF WILD TURKEYS IN RELATION TO TIMING OF SPRING HUNTING SEASONS Richard W. Hoffman P. N. OBJECTIVES 1. Document t~m~ng of winter flock dispersal, onset of gobbling, peaks of gobbling, nest initiation, onset of incubation, and peak of hatch in relation to timing of the spring hunting season. 2. Describe the gonadal cycle of females and compare the reproductive condition of females in relation to timing of the spring season. 3. Measure the abandonment rate of incubating human disturbance around the nest. 4. Monitor hunter activity and harvest females to varying levels of of wild turkeys on a statewide basis. SEGMENT OBJECTIVES 1. Review literature pertinent to the objectives 2. Trap and instrument 40 wild turkeys (6 males, 34 females) with tailor poncho-mounted radio transmitters in December-February. 3. Document timing of winter flock break-up. 4. Document onset of gobbling and peaks of gobbling activity. 5. Document onset of egg laying, incubation, 6. Measure 7. Conduct a hunter questionnaire- wing collection using a permit system and mail wing survey. 8. Compile data, analyze results, and prepare progress effects of human disturbance of this study. and peak of hatch. on rate of nest abandonment. program in Fall 1988 report. DESCRIPTION OF STUDY AREA Trapping operations were confined to Longs Canyon and 2 tributary canyons, Sowbelly and Martinez, 17 km southwest of Trinidad, Colorado, in Las Animas County. Birds dispersed into an area encompassing over 448 km2. This area was bounded by 1-25 on the east, Lorencito Canyon on the west. Colorado Highway 12 on the north, and the Canadian River in New Mexico on the south. Topography was mountainous, varying in elevation from 1800 to 2600 m. Four large canyons in excess of 30 km in length occurred within the area, each with numerous side canyons and adjacent smaller canyons. Major vegetation types included pinyon pine-juniper (Pinus edulis-Juniperus spp.), mountain shrub, and ponderosa pine (f. ponderosa). The mountain shrub type was dominated by �58 Gambel's oak (Quercus gambelii), which extended into both the pinyon-juniper and ponderosa pine types. Douglas-fir (Pseudotsuga menziesii) and occasional white fir (Abies concolor) occurred on north slopes within the ponderosa pine type. Most of the area was under private ownership except for 1100 ha of land around Trinidad Reservoir administered by the Colorado Division of Parks and Outdoor Recreation. Use of private lands was limited to cattle grazing and some logging. METHODS Trapping, Marking and Radio-tracking Wild turkeys were baited with oat hay and livetrapped in February and March using drop nets or cannon nets. Captured birds were classified to age (Hoffman 1962) and sex (Hoffman 1962), and banded with serially-numbered aluminum leg bands and patagial wing tags. Ages were recorded as subadult (810 months) and adult (> 18 months). Body weight, and length of primaries, carpal, spur, and beard were measured on each bird. Fifty-two birds were equipped with lithium battery powered transmitters attached with a poncho collar (Amstrup 1980) or tail-clip (Bray and Corner 1972). Tracking was primarily conducted from the ground using a 3-element Yagi antenna and Telonics TR-2 receiver. Aerial searches were made on 6 May and 1 June. All locations were verified by visual observation and recorded to nearest 50 m as Universal Transverse Mercator (DTM) coordinates. Gobbling Indices Flocks containing instrumented birds were monitored a m~n~mum of 3 times per week beginning on 29 February to determine onset of gobbling and period of flock dispersal. Gobbling indices were conducted from 27 March to 10 June and categorized as preseason (27 Mar-1S Apr), hunting season (16 Apr-1S May), and postseason (16 May-10 Jun). An attempt was made to conduct 3 valid indices per week per time period (i.e., AM and PM). A gobbling index was considered valid if (1) positive identification was made of the instrumented bird(s) that was gobbling, (2) the bird(s) was not disturbed prior to or during the gobbling index, (3) the time the bird left (AM gobbling index) or went (PM gobbling index) to roost was known, and (4) the index included time on and off the roost. While it was not considered necessary to know the exact number of other birds present during the index, it was necessary to know whether the male being monitored was alone or associated with other males, females, or both sexes. A gobbling index lasted 1 hour from one half hour before to one half hour after sunrise (AM index) or sunset (PM index). The 1 hour period was divided into 6 10-minute listening periods so gobbling intensity could be quantified within the i-hour interval. Gobbling was also recorded in relation to presence or absence of other birds and whether the bird was on or off the roost. Instrumented males were monitored on a rotating basis, the initial order being randomly selected. For AM indices, the gobbler was located on the roost either the evening before or 1 hour before sunrise on the monitoring morning. Gobblers selected for a PM index were located at least one hour before sunset. �59 Nesting Radio-marked hens were located at least once every 3 days from time of capture until flock dispersal. Subsequent locations varied depending on how far the hen moved from wintering to breeding area. Birds moving longer distances were relocated less frequently because it took considerable searching time to find them initially. Priority was given to locating nests and documenting hatching dates. Timing of other nesting activities (i.e., nest initiation, onset of incubation) was approximated by knowing the date of hatch. Clutch size, fertility, and nesting success were determined from egg shell characteristics after the eggs hatched or after the nest was abandoned or depredated. Hens were not approached closer than 5 m while on the nest nor were they deliberately flushed off the nest to ascertain clutch size. Permits, Questionnaires, Hunters were required and fall seasons: and Wing Collections to obtain I of 2 types of permits during the 1988 spring 1. Special Unlimited Hunting Permit - Unlimited in number and free of charge, these permits were available to any holder of a valid turkey license. Whereas the license could be purchased at any license agent, the permits were only available from CDOW offices either on a walk-in basis or by mail application. The special unlimited permits were valid for one season (spring or fall). Unsuccessful spring hunters could hunt in the fall without purchasing a new license, but before doing so, they were required to obtain another permit valid for the fall season. Successful spring hunters who wanted to hunt the fall season needed to purchased another license in addition to obtaining a special unlimited fall permit. By requiring spring and fall permits, hunters could be categorized as spring only, fall only, or spring-fall hunters and surveyed accordingly. Special unlimited permits for the spring season were available from 1 March to 15 May 1988 (end of season); those for the fall, from 1 August to 2 October 1988. Special unlimited permits were valid for all areas not requiring a limited permit. 2. Limited Hunting Permits - Limited in number, free of charge, and available by public drawing. Only mail applications were accepted for limited permits. The drawing and issuance of permits was handled through the Denver office. Hunters could apply for a limited permit without first purchasing a license. However, if they succeeded in drawing a limited permit, they needed to purchase a license before going hunting. Drawings were held on 25 March and 26 August 1988 for the spring and fall seasons, respectively. Limited permits were only valid for the area, season, and time period indicated on the permit. Holders of a limited permit were required to obtain a special unlimited permit if they hunted outside the area for which their limited permit was valid. Consequently, some hunters obtained 2 permits and were subsequently mailed 2 harvest questionnaires. This problem was identified as the questionnaires were being processed and the duplicates were excluded. Questionnaires were mailed to all permit holders immediately after the spring and fall seasons. Non-respondents were mailed a followup questionnaire approximately 3 weeks later. Mean values calculated from responses to the �60 second mailing were used to project responding to either questionnaire. answers for those permit holders not Every hunter that obtained a limited or unlimited permit was also issued a wing envelope coded by permit number. The instructions on the envelope requested each successful hunter to (1) complete the questionnaire printed on the envelope including their name, address, time of harvest, and location of harvest (county, small game management unit, and nearest town), and (2) to remove the least damaged wing and 3 or 4 breast feathers as depicted by 2 schematic diagrams, place them in the envelope, and mail the postage-paid envelope. The envelopes were addressed to the Wildlife Research Center in Fort Collins. Upon delivery, the wings were frozen until they could be processed. Information provided by hunters was transcribed onto a standardized form. The envelope's contents were examined to determine if both a wing and breast feathers were enclosed. The samples were then identified to subspecies and classified to age and sex. Whenever possible, the following measurements and feather characteristics were recorded for each wing: length, condition (growing, fully grown, empty, broken, worn, pointed) and status (adult or juvenal) of primaries I through X (numbered proximal to distal), quill diameter of P IX and P X at their insertion into the follicle, stage of primary molt, carpal length, and status (adult or juvenal) of the first secondary and tertials. Since the range of the Merriam's and Rio Grande wild turkey does not overlap in Colorado, except possibly along the Arkansas River west of Pueblo, the 2 subspecies were identified from wing samples based on the location of harvest. However, inspection of the wings suggested that subspecies could be distinguished by wing color. Rio Grande's tended to have blacker primaries and fewer white bars than Merriam's, thus, giving the wing a darker appearance. Sex was ascertained by the presence of buffy (female) of black (male) tipping on the breast feathers (Hoffman 1962). Wings were assigned to age classes based on the shape, color, wear, and barring pattern of primaries IX and X (Hoffman 1962). Juvenal primaries IX and X were pointed, grayish-brown, and lacked white barring near the tip. Comparatively, adult primaries IX and X were rounded and black or blackish-brown, with white barring extending almost to the tip. Subadults possessed the outer primaries characteristic of juveniles except they were faded and worn as a result of being retained longer. Wings obtained from the spring season were classified as adults (> 22 months) or subadults (10-11 months). Those from the fall were separated into 3 age classes: adults (> 26 months), subadults (14-16 months), and juveniles « 6 months). RESULTS AND DISCUSSION Capture and Marking Eighty-six turkeys (32 males, 54 females) were trapped in late February-early March with drop nets (27) or cannon nets (59). Three subadult hens, 39 adult hens, and 10 subadult males were equipped with leg bands, wing tags, and radios, and released at the trap site (Table 1). Two birds died during �61 Table 1. Wild turkeys trapped and equipped with radios in Longs Canyon, Colorado, February-March 1988. Band Beard Spur Sex Age Weight (kg) Carpal # (nm) (nm) (mn) 139 144 181 182 183 184 185 186 189 190 M M M M M M subad Subad Subad Subad Subad Subad Subad Subad Subad Subad 6.2 4.9 5.3 5.8 5.1 6.5 5.2 5.5 5.8 5.2 501 487 480 475 480 486 484 504 492 495 98 49 38 60 48 73 63 66 72 73 Subad Subad Subad 3.4 3.9 3.5 415 425 415 Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad Ad 4.6 4.7 4.2 4.4 4.0 4.1 3.5 3.7 4.6 3.6 4.4 4.0 4.0 4.2 4.6 4.2 4.2 4.7 4.6 4.5 4.5 4.2 4.5 4.8 4.0 3.8 4.8 4.1 4.4 4.7 4.5 4.8 4.7 5.0 4.6 4.5 4.1 4.2 4.4 440 434 446 440 410 435 431 435 460 438 437 415 424 441 437 434 434 441 435 444 446 417 438 435 442 435 453 450 442 438 446 440 442 435 440 445 443 442 437 153 179 180 27c 61c 128 129 132 133 135 136 140 141 142 151 152 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 1n 178 187 188 M M M M F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F aT = tail mount, P = poncho mount. bRadio recovered from bird 190 (mortality) and put on bird 169. cRecaptures. dRadio recovered from bird 175 (mortality) and put on bird 183. 3 3 5 2 2 3 2 3 3 4 Radio frequencya 151.159P 150.278T 150.555T 150.815T 151.596P 150.939T 150.513T 151.057T 150.762T 151.458pb 150.238T 151.662P 150.017T 175 60 159 173 170 160 150.156T 150.480T 151.424P 150.100T 150.064T 150.660T 151.678P 151.722P 150.906P 151.258P 150.079T 150.415T 151.418P 151.068P 151.513P 150.034T 151.436P 151.393P 150.869T 150.356T 151.656P 151.740P 150.400T 150.213T 150.140T 151.233P 150.305T 151.458P 150.576T 151.477P 151.574P 151.638P 151.542P 151.596pd 150.700T 151.494P 150.739T 151.617P 150.536T �62 trapping. The remalnlng 32 birds were leg banded and released at the trap site. Efforts to trap adult males were unsuccessful. No adult males were observed at the bait sites and no flocks of adult males consistently remained in one area where they could be attracted to bait. Seven (13%) of the 54 hens captured had beards. All bearded hens were adults. The beard length was 149 ± 44 mm (& ± SD). The shortest beard was 60 mm, but it was still clearly visible through the breast feathers. Beard length for subadult males was 64 ± 17 mm. Average beard length for adult males captured in 1986 was 216 ± 17 mm and for adult females 134 ± 52 mm (Hoffman 1987). Subadult males weighed 5.6 ± 0.5 kg compared to 4.3 ± 0.3 kg for adult females and 3.6 ± 0.3 kg for subadu1t females. Weights recorded in 1986 were 7.6 ± 0.6 kg for adult males, 3.9 ± 0.2 kg for adult females, and 3.0 ± 0.5 kg for subadu1t females (Hoffman 1987). Onset of Gobbling and Flock Dispersal Gobbling of adult males was first heard on 18 March and continued through 10 June when gobbling indices were terminated. Subadu1t males were first heard gobbling on 15 April and last heard on 3 June. Subadult males continually associated with hen flocks through the first week of April, whereas, flocks of adult males remained intact through March and did not start associating with hens until the first week of April. During the preseason (27 Mar-15 Apr) monitoring period, radio-marked subadult males were observed in mixed flocks (adult males and females) on 15 of 23 (65%) occasions, but were seen alone or with other jakes more often (21 of 42 observations, 50%) during the season (16 Apr-IS May) and postseason (16 May-l0 Jun) periods (Table 2). They were not seen with adult males only because adult males were usually observed with hens. However, even in mixed flocks, when adult males separated from hens or roosted separately, subadult males stayed with the hens. Table 2. Observations of subadult presence or absence of other birds. Flock composition Females and adult males Females only Adult males only Jakes only Alone (jake) male wild turkeys Preseason % II 15 1 0 3 4 65 5 0 13 17 in relation Number of observationsa Season % II 4 6 0 5 8 17 26 0 22 35 to Postseason % n 4 7 0 8 0 aConsecutive observations, where a male was indexed in the PM and again in the AM of the following day, were counted only once. 21 37 0 42 0 �63 Hens remained in winter groups into the second week of April. Smaller groups of hens were observed through late April into early May. Occasional lone hens or hens unaccompanied by adult males were encountered in late April. Such observations became more common in early to mid-May. Gobbling Indices Eighty-five (50 morning, 35 evening) valid gobbling indices were obtained on 9 subadult, radio-marked males between 27 March and 10 June. Subadult males gobbled a total of 61 times during 13 of 50 morning indices (1.2 gobbles/birdjhr) and only once (0.03 gobbles/birdjhr) during 35 evening indices (Table 3). They did not gobble during most (morning ~ 74%, evening 97%) indices. The number of gobbles per indice (n - 13) when they did gobble ranged from 1 to 28 (median - 2). They gobbled more during and after the hunting season than before the season, more on than off the roost, and more when only accompanied by hens than when alone or with other subadult males or with hens accompanied by adult males (Table 3). There was no indication that some subadult males gobbled more than others. Table 3. Gobbling activity of subadult male wild turkeys in relation to timing of the spring hunting season, time of day, roosting activity, and presence or absence of other birds. Hours of observationa Total gobbles Timing of Spring Season Preseason (27 Mar-15 Apr) Season (16 Apr-15 May) Postseason (16 May-10 Jun) 38 35 22 4 36 22 Time of Day AM PM 50 35 61 1 Roosting On Off 38.5 46.5 36 26 19 34 23 9 33 18 11 Category Activity Sex Compositionb Females Females and adult males Subadult males Alone a aListening intervals occurred from one-half hour before to one-half hour after sunrise and sunset. bSex of other birds associated with the radio-marked subadult males. Subadult males were not observed with only adult males. �64 In 1986, 94 valid gobbling indices were obtained on 7 radio-marked adult males (Hoffman 1987). Gobbling was heard during 80 (85%) of the 94 indices and averaged 25 (preseason), 35 (season), and 12 (postseason) gobblesfbird/hour. Adult males also gobbled more on (64 gobbles/hr) than off (12 gobbles/hr) the roost and more in the morning (31 gobblesfhr) than evening (7 gobbles/hr). However, unlike subadults, adult males gobbled most when alone (25 gobbles/hr) rather than when they were with females only « 2 gobblesfhr). Roosting Activity Males tended to leave the roost later as the observation intervals progressed from preseason (& - 13 min before sunrise), to season (& - 1 min after sunrise), to postseason (R - 6 min after sunrise) periods. There were only 4 of 26 morning indices prior to 28 April when males left the roost at or after sunrise. Starting on 2 May, males came off the roost after sunrise during 19 of 22 indices. Males went to roost after sunset during the preseason (R ~ 6 min) and before sunset during the season (R - 3 min) and postseason C& - 13 min) periods. Mortality Thirteen radios were recovered between 1 March and 15 July; 11 from hens and 2 from males. Eleven recoveries (10 females, 1 male) were classified as from birds that died of natural causes and 2 (1 female, 1 male) were from birds that lost their transmitters. Capture myopathy was not suspected as a cause of any mortalities in 1988. Five mortalities (including the 1 male) were documented between 7 and 27 March, 2 between 1 and 17 May, and 4 between 1 and 4 June. Only one hen was killed on the nest. Total loss of hens from late winter (1 Mar) through the nesting period (15 Jul) was 24% (10/42). Only 1 male (10%) died during this period. Both transmitters thought to have been lost were tail mounts. The nuts holding the transmitters to the tail came loose on one of the tail mounts. The other tail mount was found still attached to the 2 central tail feathers. No other feathers were found near the transmitters, nor had the transmitters sustained any damage (i.e., tooth marks, scratches, etc.). Nesting Eleven (31%) of 36 hens surviving into the nesting season nested successfully; whereas, 12 attempted to nest but failed, 2 were suspected of laying when predated, 1 was predated on the nest, and 10 either did not attempt to nest or lost or abandoned their clutch prior to onset of incubation. One renest attempt was documented. This hen lost her first clutch between 23 and 31 May and was relocated on a second clutch on 24 June. The second clutch was predated on -8 July. Clutch size of first nest attempts was ascertained from egg shell fragments for 8 nests (& = 9.2, range - 8-11); 70 (95%) of the 74 eggs hatched successfully. The earliest known date for onset of incubation for a first clutch was 5 May and the latest was 8 June. Seven hens initiated incubation prior to the conclusion (15 May) of the spring hunting season, 12 started between 16 and 31 May, and 4 started between 1 and 8 June. Five of the 7 hens starting before the season ended initiated incubation the last week of the season. The peak period for onset of incubation was 11-25 May; 16 hens (70%) initiated incubation during this period. �6S Movements Nine subadult males moved 8.7 ± 3.1 km from wintering to breeding areas. Adult males in 1986 moved 3.7 ± 1.7 km (Hoffman 1987). Females moved longer distances (1988 - 11.8 ± 5.7, 1986 - 9.6 ± 4.3) than adult or subadult males. Hunter Compliance - Permit System A total of 4,569 permits was issued for the spring season and 5,078 licenses were sold. Hunter compliance with the spring permit requirement was 90%. Questionnaires were sent to all permit holders by 1 June 1988. A followup questionnaire was mailed to the non-respondents 3 weeks later. The combined return rate for the first and second mailing was 72% (Table 4). There were more permits issued (1,599) for the fall season than there were licenses sold (889). The reason was that unsuccessful spring hunters who wanted to hunt the fall season were not required to purchase another license, but were required to obtain a fall permit. Consequently, total license sales and total permits issued were not directly comparable in evaluating hunter compliance. Instead, hunter compliance was measured as the proportion of new license buyers who also obtained a permit. The estimate was 88% (782 of 889). Questionnaires were sent to the 1,599 fall permit holders of which 58% were returned. A followup questionnaire was sent to the 669 non-respondents and 233 additional responses were received. Seventy-three percent of the fall hunters responded to the questionnaire (Table 4). Table 4. Response Surveys mailed Surveys returned Percent return Non-deliverable aTotal hunters Hunter Activity to the 1988 spring and fall turkey harvest survey. 1st SRring 2nd Totals 1st Fall 2nd 4,569 2,527 55 90 2,042 740 36 35 4,569a 3,267 72 125 1,599 930 58 26 669 233 35 14 Totals 1,599a 1,163 73 40 sampled. and Harvest - Questionnaire Projected estimates for the spring season indicated that 3,819 hunters harvested 671 turkeys for a success rate of 18% (Table 5). Total harvest including a reported crippling loss of 13%, was estimated at 771 birds. Spring hunters averaged 3.4 days afield over the course of the 30-day season from 16 April to 15 May. There were 68% fewer hunters that participated in the fall season (1,225 hunters) and 47% fewer birds (355) were harvested (Table 6). However, hunter success (29%) was higher. Crippling loss (14%) was similar. Hunters in fall spent 2.8 days afield, but had only 16 days (17 Sep-2 Oct) of hunting which included just 3 weekends. The spring season �66 lasted 14 days longer, opportunity. Table 5. allowing for 2 additional weekends of hunting 1988 spring turkey harvest and hunter activity. Descriptive statistic 1st Mai lins 2nd 1: Projected for Totals in sample hunters hunters hunters observing turkeys hunters observing turkeysb successful huntersb(harvest) successful hunters N hunter da~s Days/hunter Crippl ing loss % crippling loss Total harvest 2,527 2,349 93 1,658 71 451 19 7,715 3.3 58 11 509 740 533 72 373 70 79 15 1,948 3.7 15 16 94 3,267 2,882 88 2,031 70 530 18 9,663 3.4 73 12 603 1,302a 937 72 656 70 141 15 3,186 3.4 27 16 168 4,569 3,819 84 2,687 70 671 18 12,849 3.4 100 13 771 1: Projected for Totals 1i 1i % 1i % 1i % aNon-respondents. bBased only on those license holders who actually hunted. Table 6. 1988 fall turkey harvest and hunter activity. Mail ins Descriptive statistic 1st in sample hunters hunters hunters observing turkeys hunters observing turkeysb N successful hunters (harvest) b % successful hunters N hunters days Days/hunterb Crippl ing loss % crippling loss Total harvest 930 709 76 389 55 246 35 1,985 2.8 34 12 280 1i 1i % 1i % 2nd 233 180 77 100 56 38 21 486 2.7 9 19 47 1,163 889 76 489 55 284 32 2,471 2.8 43 13 327 436a 336 77 188 56 71 21 907 2.7 17 19 88 1,599 1,225 77 677 55 355 29 3,378 2.8 60 14 415 aNon-respondents. bBased only on those license holders who actually hunted. Most hunting pressure and harvest occurred on opening weekend during both seasons (Table 7). Pressure and harvest did not change substantially over the remainder of the fall season. There was an increase in pressure on weekends during the spring season. The Southeast Region accounted for 76% of the spring and fall harvest (Tables 8, 9). Las Animas County was the leading harvest area with 21 and 29% of the spring and fall harvest, respectively. Public land supported 54% of the spring and fall hunting pressure, but produced only 42% (spring) and 34% (fall) of the harvest (Table 10). �67 Table 7. Chronological distribution of hunting pressure the 1988 spring and fall wild turkey seasons.a Date 1st 1st 2nd 2nd 3rd 3rd 4th 4th 5th weekend week weekend week weekend week weekend week weekend Totals SQring; Hunter da::x:s Harvest % % N N and harvest Fall Hunter da::x:s % N during Harvest % N 1,880 979 1,094 772 1,388 812 1,197 572 969 20 10 11 8 14 8 13 6 10 178 60 70 37 48 30 28 27 26 35 12 14 7 10 6 6 5 5 927 400 467 322 242 39 17 20 14 10 109 42 47 36 49 38 15 17 13 17 9,663 100 504 100 2,358 100 283 100 aBased on hunter days and harvest periods. that could be assigned to specific time Hunter success averaged 26% on the spring limited permit areas, exceeding the statewide success rate of 18% on all but 2 areas (Table 11). The eastern plains limited permit areas continued to produce high hunter success rates. Hunter success (27%) on the fall limited permit areas approximated the statewide average of 29%. However, fall hunter success on both eastern plains permit areas surpassed the statewide average. It was a definite advantage to hunt on private (spring = 29% success, fall = 56% success) vs. public land (spring ~ 14% success, fall - 21% success) in both seasons. Seventy-three percent of the birds harvested during the spring season were taken before noon; 54% were harvested between 0500 and 0900 hours (Table 12). Only 19% were not associated with other birds at the time of harvest (Table 13). Most (47%) were taken f~om flocks comprised of 1-5 birds. The remaining 34% were taken from flocks with 6 or more birds. There was no indication that hunters encountered smaller flocks as the season progressed. Hens undoubtedly were present in the larger flocks, suggesting they were still receptive to males and not incubating. Wing Collection Program Limitations - The validity of any population index calculated from harvest samples is dependent upon the assumption that different age and sex classes are harvested in proportion to their occurrence in the population. Long-term population and harvest data are often necessary to test this assumption. Such data are not available for the Merriam's wild turkey in Colorado or elsewhere throughout its range. In addition, if wings are collected over a broad geographic area, they may not accurately reflect characteristics of local populations. These limitations do not preclude the use of wing data as a tool in formulating management strategies. Biologists must be aware of them and use caution in interpreting the data. �68 Table 8. ~ild turkey harvest by County, Game Management Unit, and Region, Spring 1988. Harvest Harvest County !!. Las Animas Harvest X GMU !!. X 110 21 Fremont 51 10 Pueblo 50 10 84 85 140 143 711 421 96 59 73 54 43 31 27 26 23 23 14 11 8 6 5 103 ] 109 107 69 581 851 86 71 58 511 42 20 123 144 136 78 135 130 83 771 38 118 147 40 77 19 51 501 56 41 142 39 145 128 46 95 99 461 57 751 146 137 19a 4 18 13 12 12 11 10 9 8 8 8 6 5 5 5 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3 2 2 2 1 1 1 1 1 1 1 3 3 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 < 1 < 1 < 1 < 1 <; 1 <; 1 < 1 < 1 < 1 < 1 514 7 100 Huerfano 41 8 Custer 35 7 31 6 Washington Morgan 23a 4 Dolores 22 4 19a 4 Kit Carson El Paso 18 3 Baca MontezUlla 17 17 3 3 Archuleta Teller 12 11 2 2 Larimer Garfield 10 2 2 Jefferson 6 Otero 6 Chaffee 4 Bent 4 Costilla Parle: 4 3 Clear Creek Delta Douglas Gi lpin Adams Weld Boulder La Plata 2 2 2 2 1 1 1 1 Totals Unknowns 514 7 Mesa lo,oo ] Yuma t incctn ] 8 < < <; < < < <; < 1 1 1 1 1 1 1 1 100 Region !!. SE 369 72 S~ 58 11 NW 39 8 NE 34 6 Central 14 3 514 7 100 % 5 4 4 aHarvest was pooled by area which included more than one county or GMU. �69 Table 9. Wild turkey harvest by County, Game Management Unit, and Region, Fall 1988. County Las Animas Fremont Pueblo Custer Huerfano Yuna ] Kit Carson Mesa El Paso Logan ] lIashington Morgan Larimer Archuleta I !! X GMU !! X 81 39 29 22 21 12a 29 14 10 8 7 4 47 41 27 22 19 19 12a 17 15 10 8 7 7 4 11 8 4 3 84 85 140 69 59 143 103 ] 109 86 96 421 851 130 20 19 136 58 n1 581 9 3 3 3 3 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 8a 3 8 7 3 2 ~ Baca 6 2 P Otero 5 2 Bent 4 Douglas 3 Teller 3 Chaffee 3 Costilla 2 Garfield 2 Jefferson Gi lpin LaPlata Clear Creek Totals Unknown rr < < < < 278 9 51 56 511 40 144 135 147 42 461 741 83 39 146 38 41 123 1 1 1 1 100 8 8 8 6 4 4 4 4 4 3 3 3 3 2 2 2 2 2 2 1 1 1 1 1 1 1 1 < < < < < < < < Region !! SE NE Nil 233 16 13 10 6 84 6 5 3 2 278 9 100 511 Central 100 278 9 % aHarvest was pooled by area which included more than one county or GMU. Table 10. Distribution of hunting pressure and harvest by land status during the 1988 spring and fall wild turkey seasons. Fall 512ring Hunters Land status Public Private Both Totals !! Harvest X Hunters Harvest !! x !! x !i % 1,521 1,026 288 54 36 10 219 302 42 58 438 327 50 54 40 6 94 183 34 66 2,835 100 521 100 815 100 zn 100 �70 Table 11. Hunter success on limited permit areas during the 1988 spring and fall wild turkey seasons. Spring Permit areas Permits issued Lake Dorothey Beaver-Skagway Units 103 and 109 Units 107, 108, ll2, ll3, ll4, ll5, 120, 121 Unit 96 Colorado Spgs. SWA Spanish Peaks Unit 42 East Harvest 75 30 40 20 15 6 70 22 Fall Success (%) 13 Permits issued 17 10 37 30 65 30 20 31 20 20 1 10 6 60 250 66 26 3 5 b Success (%) Harvest 8 8 12 12 27 60 7 35 23 28 a a 81 t a 1 Q Totals aC10sed to fall hunting. bNo restrictions on numbers of hunters 216 58 27 during the spring season. Table 12. Distribution of harvest by time period during the 1988 spring and fall wild turkey seasons. Fall Spring Time period 0500 0600 0700 0800 0900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 - 0559 0659 0759 0859 0959 1059 1159 1259 1359 1459 1559 1659 1759 1859 1959 aMountain Daylight N 7 88 107 64 46 33 18 10 18 9 10 21 20 29 15 Time. % N % 1 18 22 13 9 6 4 2 4 2 2 4 4 6 3 16 34 22 32 24 12 10 7 6 10 25 27 22 6 14 9 13 10 5 4 3 2 4 10 11 9 �71 Table 13. Size of flocks from which turkeys were harvested spring season. during the 1988 Flock size oa , 2-5 Date of harvest N % 16-20 Apr 21-25 Apr 25-30 Apr 1-5 May 6-10 May 11-15 May 37 14 18 8 9 8 Totals 94 > 10 6-10 N % 39 15 19 8 9 8 103 45 22 16 21 23 19 230 N % N % 45 20 9 7 9 10 39 14 9 12 9 7 43 16 10 13 10 8 37 18 8 7 3 5 47 23 10 9 4 6 47 90 18 78 16 I ~ aBird was alone. Compliance - Of the 530 successful spring hunters who responded to the questionnaire, 402 (76%) said they returned a wing. However, 499 wings were processed, meaning 97 successful hunters who did not respond to the questionnaire still returned a wing. The wing collection program sampled 74% (499/671) of the spring harvest. A total of 249 wings was collected from the fall wing survey representing 70% of the estimated fall harvest. Seventy-nine percent (213/284) of the successful hunters responding to the fall questionnaire indicated they returned a wing and 36 successful hunters not responding also returned a wing. Subspecies Composition - The Merriam's wild turkey was the dominant subspecies identified from inspection of wings. It comprised 90 and 92% of the spring (Table 14) and fall (Table 15) samples, respectively, and was harvested in 27 of Colorado's 63 counties. Rio Grande's were taken in 8 counties. Fremont, El Paso, and Pueblo were counties where both subspecies were harvested. The 48 Rio Grande wings collected during the spring season originated from the following areas: 19 from Unit 96, 17 from Units 103/109, 5 from Unit 123, 3 from Unit 951, 3 from Unit 118, and 1 from Unit 84. Only 19 Rio Grande wings were identified in the fall sample of 249 wings: 8 from Unit 96, 7 from Units 103/109, 3 from Unit 84, and 1 from Unit 59. Sex Composition - Seven (2%) wings examined from the spring sample were from females (Table 14). All were Merriam's and all were assumed to be from bearded hens. Two percent of the total spring harvest (n - 13) is probably a reasonable estimate of the legal harvest of hens. At this level of harvest, spring hunting should have minimal impact on the female segment of the population. �72 Table 14. Sex, age, and subspecies based on wing analyses. composition Males of the 1988 spring harvest Females Subadu1t Adult Subspecies Subadu1t Adult Merriam's Rio Grande's 147(33)a 24(50) 294(66) 24(50) 0(0) 0(0) 7(1) 0(0) 448b 48 Totals 171 (34) 318(65) 0 7(1) 496 Totals apercent. bThree additional Merriam's wings were processed but could not be classified to age or sex bringing the total wings collected to 499. t I ~ Table 15. Age, sex, and subspecies composition of the 1988 fall harvest based on wing analyses. Subspecies Males x Ii Adults Females % Ii Merriam's Rio Grande's 56 42 2 29 76 5 58 71 Total x Ii 132 57 7 37 Males Ii % 0 0 0 0 Subadults Females Illil Ii x Ii % 9 100 9 1 100 1 4 5 Males x Ii 52 58 5 45 Juveni les Females Total % % Ii Ii 37 42 6 55 89 39 11 58 Sample size Poul ts/ hen 230 19 1.0 1.8 Examination of wings (Merriam's only) originating from the fall season revealed the sex ratio of adults and subadults combined favored females (1.5 females: 1 male), while the sex ratio of juveniles favored males (1.4 males 1 female). The biological implications of these ratios are difficult to interpret without knowledge of the population structure. However, in a promiscuous species such as the wild turkey, sex ratios should favor females. Age Composition - Sixty-six percent of the spring harvest (males only) of Merriam's wild turkeys were adults compared to only 50% for Rio Grande's. Rio Grande populations in Colorado are the result of recent (since 1981) introductions. Available evidence suggest these populations are still increasing and expanding into unoccupied ranges, while populations of Merriam's wild turkeys have remained stable or declined. The age composition of the Rio Grande harvest reflects good production, survival, and recruitment of young birds, attributes indicative of an increasing population. Subadult males in the increasing Rio Grande populations may not be suppressed by mature males from participating in breeding activities. If so, subadults should be equally, if not more vulnerable due to their inexperience, to the calling tactics of hunters. The following discussion regarding the age composition of the fall harvest pertains to the Merriam's wild turkey. Samples of Rio Grande wings from the fall season were inadequate for meaningful interpretation. �73 Subadults comprised 4% of the fall harvest including juveniles and 6% excluding juveniles (Table 15). Biologically, this could be interpreted as poor production in 1987 and subsequent low recruitment into the 1988 population. However, anpther factor contributing to the low number of subadults is associated with the onset of primary molt and whether key feathers (primaries IX and X) for separating adults and subadults are still present at the time wings are collected. If these feathers have already molted, subadults cannot be distinguished from adults. This was the case as 100% of the males and 51% of the females had completed their primary molt by the fall season. The problem of separating adults and subadults was compounded for males because they start and finish their primary molt before females. Misidentification of subadults is not a problem in spring when birds are beginning molt of primary feathers. Percent juveniles in the harvest (39%) and the ratio (1:1) of juveniles to adult and subadult females were used as indices to productivity. The 2 indices suggested poor production of young in 1988. LITERATURE Amstrup, S. C. 44:214-217. 1980. A radio-collar CITED for game birds. J. Wildl. Manage. Bray, O. E., and G. W. Corner. 1972. A tail clip for attaching to birds. J. Wildl. Manage. 36:640-642. Hoffman, D. M. 1962. The wild turkey in eastern Colorado. Game and Fish. Tech. Publ. 2. 49pp. transmitters Colorado Dep. Hoffman, R. W. 1987. Chronology of breeding and nesting activities of wild turkeys in relation to timing of spring hunting seasons. Job Prog. Rep. Colorado Div. Wildl. Fed. Aid Proj. W-152-R. Apr. 1987. Pp. 199-232. Wildlife Researcher ��75 Colorado Division of Wildlife Wildlife Research Report April 1989 INTERIM FINAL REPORT State of: Colorado Project: W-152-R Upland Bird Research Work Plan: 13 Job Title: Seasonal Habitat Use by Plains Sharp-tailed County, Colorado Period Covered: Author: Job _9_ 01 January through 31 December Grouse in Douglas 1988 Anthony W. Hoag Personnel: C. E. Braun, K. Demarest, D. Prenzlow, M. Wertz, Colorado Division of Wildlife; A. W. Hoag, E. Redente, Colorado State University ABSTRACT The status and habitat use by plains sharp-tailed grouse (Tympanuchus phasianellus jamesii) were investigated during 1986-88 in Douglas County, Colorado. This grouse once occupied suitable habitats in northeastern Colorado, but the range of this subspecies in Colorado has been greatly reduced because former habitats have been altered by man. Within Colorado, the estimated population size in 1986-88 was l75~225 birds existing only in Douglas County in an area with 6 known leks and 2 historic lek sites. Habitat use was studied by capturing 23 grouse on 4 leks and fitting them with solar-powered radios. Seven habitat variables and 7 sharp-tailed grouse activities were studied. Habitat use varied by season and sex. Shrub communities were selected in fall, winter, and for escape and nesting. Transition zones between shrubs and grasslands were selected in spring, and for roosting and nesting. Grasslands were selected in summer and for feedingloafing, and mating activities. Home range size varied between 103 and 363 ha for males, and 306 and 884 ha for females. Management of private_l,?-nds with plains sharp-tailed grouse in Colorado should focus on mainta:Lning residual vegetation from the previous year to increase cover for nesting, brooding, feeding-loafing, and roosting, A draft thesis incorporating 2 manuscripts for publication has been submitted to fulfill requirements for the Master of Science degree in Range Science. ��Colorado Division Wildlife Research April 1989 of Wildlife Report 77 JOB PROGRESS REPORT State of: Colorado Project: W-152-R Upland Work Plan: 14 Job Title: Seasonal Period Covered: Author: Job 3__ Movement 01 January Bird Research and Habitat Use by Greater through 31 December Prairie-Chickens 1988 Michael A. Schroeder Personnel: M. A. Schroeder and G. C. White, Colorado State University; C. E. Braun, F. Pusateri, and L. A. Robb, Colorado Division of Wildlife ABSTRACT Investigations were continued to examine seasonal movements and habitat use of greater prairie-chickens (Tympanuchus cupido) in northeastern Colorado. Habitat use was variable within each season, and differences between observed and available habitat sites generally were unclear. Behaviors such as nesting, foraging, and breeding appeared to be more important than either sex or season for interpreting use of habitat. Leks were associated with areas of sparse, short cover and nests were in areas dominated by dense, tall cover. As with habitat use, home range size frequently was unclear. However, females typically had larger home ranges than males and yearling males had larger home ranges than adults. Relatively large movements by females during the early summer season dramatically increased average home range size and its standard deviation. Whether these movements represent dispersal or migratory movements is not clear. The evolution of lek behavior has been explained by the female preference hypothesis which suggests that females select large clusters of males for mating purpos.es. Predictions that females should have spring home range diameters equal to Lnce r -Lek distances and that most females should visit only 1 lek during. the breeding season were tested by monitoring (with radio telemetry) female greater prairie-chickens during the breeding seasons of 1986-88 in northeastern Colorado. In contrast to the predictions, 66 of 90 females (73%) had their nests closer to a lek other than that where first observed or captured. Females nested an average of 3.67 km from the lek where first observed or captured, and an average of 1.02 km from the nearest lek. Likewise, 59 of 79 (75%) visited more than 1 lek during the breeding season. These data clearly illustrate that the female preference hypothesis is not applicable to greater prairie-chickens in northeastern Colorado. In addition, female movement in relation to lek dispersion is an important management consideration. The designation of an arbitrary zone of habitat around leks may not be valid for determining critical habitat for greater prairiechickens. ��79 SEASONAL MOVEMENT AND HABITAT USE BY GREATER PRAIRIE-CHICKENS Michael A. Schroeder P. N. OBJECTIVES 1. Quantify seasonal habitat use, movements, and lek attendance prairie-chickens in northeastern Colorado. of greater SEGMENT OBJECTIVES 1. Relocate all radio-marked greater prairie-chickens at least 20 times during the late summer (1 Jul - 15 Aug) and periodically through the winter. 2. Analyze movement and habitat use of greater prairie-chickens to cover types as mapped on the entire study area. 3. Describe vegetation at all greater prairie-chicken Analyze habitat use for each season and sex. 4. Document reproductive parameters, marked greater prairie-chickens. 5. Analyze the dispersion of home ranges of female greater prairie-chickens during the breeding and nesting seasons to test hypotheses about lek evolution and territoriality. 6. Compile and analyze data, and prepare movements, relocation and survival in relation sites. for all radio- annual report. METHODS An area centered 20 km northwest of Wray, Colorado was chosen for research on greater prairie-chickens. A study area of 301 km2 was monitored in 1986-88 to estimate lek density and determine male lek attendance (Fig. 1). Two or more displaying males were considered a lek. Attendance for each lek (within a year) was estimated by using the maximum count of males at that site. Trapping efforts were concentrated on a core area of approximately 75 km2 (Fig. 1). Birds were trapped at winter feeding sites using walk-in traps baited with corn and at leks using walk-in traps and cannon nets. All captured birds were banded with a numbered aluminum band and a unique combination of 3 colored plastic bands. Age was ascertained by examining patterns of feather wear (Ammann 1944). Bird ages were: yearlings, 5-17 months of age (1 Nov of 1st year to 31 Oct of 2nd year) and adults, older than 17 months of age (after 31 Oct of 2nd year). Battery- and solar-powered radio transmitters were attached to poncho-type markers (Amstrup 1980) and placed on greater prairie-chickens in 1986-88. Radio weights were between 1.8 and 2.3% of each birds' body weight. �80 N MEAN YEARLY LEKATTENDANCE o 0-1 MALES o >103MALES o o o o >3-8MALES >11-10 MALES >10-15 MAl.!8 >15MAl.!8 CAPTURE LOCATIONS * FEEDING AREAS • LEKS R47W! •• -:- R46W ~ - =- ~ ••.•• -:- R45 W ~ - ~ ~ •• .,. -:- , .. ~ _,_ • _:_ •... ~ _!_ .,._:_ ~ - R44 W •••• ~ -!- ~-:- ~..~ -:-1 4. _:_ ••• ,_ _: •• ., _: ••.•. _ •• _ iii R 47 W i i R 46 W R 45 W R 44 W o 2 4 km Fig. 1. Greater prairie-chicken study area in 1986-87 (301 km2 outlined bv solid boundary) and in 1988 (932 km2 outlined by dashed boundary) in north-eastern Colorado. �81 Seasonal collection periods were early spring (15 Feb -31 Mar), late spring (1 Apr - 15 May), early summer (16 May - 30 Jun) , late summer (1 Ju1 - 15 Aug), autumn (16 Aug - 31 Oct), and winter (1 Nov - 14 Feb); designation of seasons was based on aspects of breeding behavior and movement (Robel et al. 1970Q). Time periods were defined as morning (0.75 hours before - 2.75 hours after sunrise), mid-day (2.75 hours after sunrise - 2.75 hours before sunset), and evening (2.75 hours before - 0.75 hours after sunset). Radio-marked prairie-chickens were tracked using a portable receiver and a 3-element yagi antenna. Each bird was visually observed once every 21-28 days and additional observations were obtained by triangulation; azimuths were obtained within 1.0 km of the target transmitters and at angles-of-incidence greater than 35° and less than 145°. Initial estimates of accuracy suggested that locations derived by triangulation had a 95% probability of being within 200 m of the actual location. All locations were recorded using Universal Transverse Mercator coordinates (nearest 10-m interval). Home range size was estimated as the area within a 75% probability contour generated with harmonic means on a grid size of 25 X 25 for each radio-marked bird for each season (Dixon and Chapman 1980). Habitat was examined at both observed and 'available' sites. Three observations were collected for each sex, age, season, and time period. Available sites were chosen relative to observed sites (modification of a stratified sampling method) and were randomly selected within a 0.5-krn circle (0.5 krn was representative of a typical prairie-chicken flight distance) centered over the observed site. One available site was measured for each observed site. To eliminate problems associated with measuring habitat variables in a changing environment (e.g., snow cover, plant growth, grazing pressure), both sites were examined on the same day. Two 18-m perpendicular transects were established in the center of the site with orientation of the initial transect being randomly determined. Ten point-intercept locations, 2 m apart, were located along each transect (total of 20 points). All plant species intercepted at each point were identified and recorded. Plant names follow Scott and Wasser (1980) and Harrington (1964) (Appendices A, B). Statistical analyses were used to compare general categories and/or common species including; sand sagebrush, needle-and-thread, sixweeks annual fescue, blue grama, sand dropseed, and prairie sandreed. Height-density-index (HOI) was recorded from a height of 1 m and at a distance of 4 m to one side of the transect for all 20 points. HOI was recorded as the height of vegetation obstructed on a Robel Pole (to the nearest 5 cm) (Robel et a1. 1970~). Heights of sand sagebrush, grasses, and forbs were recorded to the nearest 5 cm. A single 25-m2 circle was also centered on each site (2.82 m diam) and all plant species within the circle were identified and recorded. Location, slope, and aspect were also recorded at each site. Habitats were statistically compared with Lmax and ~ tests (assuming unequal variances). Habitat on the main 301 krn2 study area was also mapped according to dominant habitat types. Since the study area was generally divided in management units that were portions of sections (1 section - 1 mi1e2 - 640 acres), mapping was initiated by first dividing each section into 64 smaller units of 10 acres (about 4 ha). Each unit was classified as 1 of 45 different dominant habitat types. The only deviation from this method was that roads and areas of center-pivot irrigation were mapped without regard to the underlying division of units. Each habitat is described in detail in this report. �82 Female Preference Hypothesis Areas believed to be important for greater prairie-chickens, and grouse in general, are often selected by delineating an arbitrary circumference of habitat around all known leks. These areas are considered crucial for nesting habitat, a factor considered when for habitat disturbance or loss. However, little is known about movements and nest sites in relation to lek location. lekking generally mitigating female Research on lekking systems in other species has provided testable hypotheses that may help in understanding the evolution of a lekking breeding behavior from its hypothesized territorial precursor. One particular theory, the 'female preference' hypothesis, has been proposed by Bradbury (1981). Bradbury suggested that increase in female home range size is responsible for the transition from a territorial to a lekking breeding system. He further hypothesized that lek dispersion is based on female home range size and the detectability of leks. Bradbury also suggested that females should prefer to visit a cluster of males, rather than a single male, thereby improving their opportunities for mate choice. Bradbury (1981) specifically predicted that: 1) the diameter of female home ranges should be less than inter-lek distances; 2) most females should have only 1 lek within their home range; 3) females located between leks will be exceptions and will visit either or both leks within their range of detection; and 4) each lek should have an exclusive population of females. Thus, it would be expected that most females should visit only 1 lek. I examined Bradbury's predictions for the 'female preference' hypothesis by determining lek - nest distances (an indirect measure of home range size) and lek visitation behavior of female greater prairie-chickens. RESULTS Three different trapping methods were used to capture 373 (including 122 recaptures) greater prairie-chickens during 1986-88 (Table 1). Since cannon nets were considered to cause more disturbance than other trapping methods, they were used only sparingly in 1986. Walk-in traps were extremely effective during both winter and breeding seasons. Their success was positively correlated with snow cover in winter and date during the breeding season (Table 2). A total of 243 different greater prairie-chickens was captured and banded in 1986-88 (Table 3); radios were fitted to 145 birds. Measurements of primary length and diameter, pinnae length, and weight demonstrated that adults were generally larger than yearlings within each sex (Table 4). In addition, males were larger than females within each age category for all feather measurements and weights (f < 0.01). The lengths of primaries I, II, and IX and the diameter of primary IX were the best measurements for discriminating between sex and age categories. Although weight also may be a useful measurement, weight was variable with respect to season (Fig. 2). For example, females weighed more during the breeding season than in winter (f < 0.05); males did not differ. Weight variation within the breeding season was also examined (Fig. 3); weights for males declined and weights for females increased. �83 Table 1. Number of greater prairie-chickens captured by different in 1986-88 in northeastern Colorado (including recaptures). Walk-in traps at winter feeding sites Category Walk- in traps at lek sites techniques Cannon nets at lek sites Totals Males Adults Yearlings 76 32 44 86 56 30 21 14 7 183 102 81 Females Adults Yearlings 52 30 22 132 61 71 6 2 4 190 93 97 128 218 27 373 Totals Table 2. capturing Colorado, Trapping Trapping success rate (percent captures per trap per day) for greater prairie-chickens with walk-in traps on leks in northeastern 1986-88. period 4 Mar - 10 Mar 11 Mar - 17 Mar 18 Mar - 24 Mar 25 Mar - 31 Mar 1 Apr - 7 Apr 8 Apr - 14 Apr 15 Apr - 21 Apr 22 Apr - 28 Apr > 28 Apr Trap days Males Females All captures 62 59 173 384 435 389 283 91 39 3.2 1.7 3.5 0.8 6.9 6.7 4.2 4.4 5.1 0.0 0.0 1.2 2.1 9.2 12.3 11.7 1.1 0.0 3.2 1.7 4.6 2.9 16.1 19.0 15.9 5.5 5.1 �84 Table 3. Number of greater prairie-chickens banded and fitted with radio transmitters, and their fates, in northeastern Colorado, 1986-88. Fates of radio-marked birdsa Capture data Bands Radiosb Males Adults Yearl ings 108 61 47 34 20 14 5 38 2f 7 4 Females Adults Yearl ings 135 65 70 111 48 63 Totals 243 145 Category Removedc Lostd Predated 3 9 5 4 13 6 7 4 4 0 3 2f 1f 19 11 8 44 17 27 35 14 21 13 6 7 8 26 53 48 17 Mortalities aAs of 31 Dec 1988. bBirds with radio transmitters were also banded. CAt least 20 radios were recovered after premature loss. dBirds potentially were lost because of several reasons including: inoperative radios on live birds, and inoperative radios on dead birds. 9Three birds died of heat stress. fRaptors killed 5 birds in traps in a 3-day period. Table 4. long untracked movements, Measurements of greater prairie-chickens captured in northeastern Colorado, 1986-88. Malesa Adults Measurement At ive Femalesa Yearl ings Adults e. !!. -~ SO 0.36 0.28 0.31 0.46 0.49 0.58 0.43 0.46 0.39 0.57 *** *** * ** ** *** * 61 61 61 61 60 60 59 75 75 76 11.34 11.72 12.28 13.44 16.65 16.37 16.51 16.37 15.40 12.36 3.19 0.11 *** 59 7.72 0.52 49 ~ SO !!. ~ SO 11.69 12.07 12.66 14.01 16.43 17.16 17.31 17.27 16.28 12.93 0.42 0.38 0.41 0.50 0.56 0.59 0.46 0.45 0.57 0.53 35 34 33 35 35 36 35 56 55 57 11.23 11.76 12.45 13.70 16.27 17.10 17.33 17.04 15.70 13.19 Primary IX diameter (mm) 52 3.39 0.12 55 Pinnae length (em) 51 0.47 27 !!. Primary length (cm) I 59 II 59 III 59 IV 57 V 56 VI 59 VII 59 VII I 73 IX 72 X 75 7.93 Yearlings b e.b !!. ~ SO 0.44 0.63 0.70 0.63 0.56 0.53 0.59 0.62 0.69 0.45 58 58 58 58 57 56 56 76 75 77 10.84 11.32 11.96 13.04 15.33 16.19 16.45 16.23 14.94 12.47 0.31 0.33 0.38 0.39 0.48 0.45 0.40 0.40 0.52 0.39 *** *** ** *** *** * 3.26 0.10 61 3.11 0.12 *** 3.78 0.50 50 3.62 0.52 *** lJeight (g) 100 1034.8 60.8 78 1011.1 46.8 ** 93 899.7 58.6 93 871.0 60.5 aMeasurements for males and females within each age category differed (e. < 0.01, !test). bThe probability for differences in measurements (1 test) between adults and yearlings within each category of sex were: * = e. < 0.05, ** = e. < 0.01, and *** = e. < 0.001. ** �1200 1100 ,............. 0> "'--" 1000 l- I (!J W 900 N=32 N=27 N=46 N=73 800 N=67 ~ N=16 700 N=26 N=77 ~~--------------------------------------------------------------- WINTER SPRING ADULTS WINTER SPRING YEARLINGS MALES WINTER SPRING ADULTS WINTER SPRING YEARLINGS FEMALES J1ig. 2. Mean (horizontal bar), range, (vertical bar), and standard error (enclosed horizontal bars) of seasonal weigllts for each sex and age category of greater prairie-cllickens in nortlleastern Colorado, 1986-88. OJ VI �• 1'- 1150 IHlO ICI50 ............_. 0> '-"'" lI (!J w ~ IHlO ••• .t. • •••••••• ~,~ •• - - •• ~ ICIIIO .. . 1t•• _ I • _ II - • YEARUNG MALES l21li • • .II ••••• ..~-= ;.;;. ... •- •.• ' ~+----r--~---;r_--~--or--~---,~--~--~--, II II .II • 51 5 6 .III • • -t---,---,---,---,---,---,---,---,---,---, , .III 10 ~ aD •• • 51 • •• I lID • • lIID ••+----r--~---,r_--~--,_---r--_.----r_--~--, II o. S • •• • •• - • • • • •• • •• " •• • 00 YEARUNG FEMALES 1150 -.- •• • •• • 1Il10 • .. • ••• .. •• - • - ••• • . . •• .:.• ..• -L.. .. .::-,~• .. - .~.~.i . •I·.·· • • • . - • •• ••+---_r---.r_--~--_r--_,r_--~--_r--_,r_--~--~ .III 10 • .III II 51 • II • ICI50 • ... .'~~ s·. •• ICIIIO-i. ADULT FEMALES ADULT MALES • APR .III 10 • MAy .III • II II .II ••••• •••• • 51 10 iii aD 2Ii APR DATE Fig. 3. Weights for adult male (~= 73, y = -l.08x + 1075.89, ~2 = 0.071, f = 0.023), yearlng male (n = 46, y = -0.67x + 1039.03, r2 = 0.072, P = 0.072), adult female (n = 66, y = 2.l8x + 859.76, r2 0~134, f = 0.003), and yearling-female (~=-74, y = 2.83x + 708.77, ~7 = 0.154, P = 0.001) greater prairie-chickens captured in northeastern Colorado during the 1986-88 breeding s;asons. �87 Density Sixty-five leks were documented on the 301 km2 inner study area during 198688; 36 additional leks were found on the surrounding 631 km2 area in 1988 (Fig. 4, Table 5). Eleven additional display sites with single males were also documented. The density of leks on the inner study area was relatively stable at 0.14 leks/km2 (0.37 leks/mile2) (Table 6). The mean distance between nearest neighboring leks was 1.31 (SD - 0.56), 1.20 (SD - 0.70), and 1.18 (SD - 0.62) km for each year, respectively (medians of 1.42, 1.32, 1.15 km). The slight increase in lek density between 1987 and 1988 was mirrored by a significant increase in maximum attendance of males at leks (~= 4.760, f = 0.001). The 1988 density of leks on the surrounding area was 0.06 leks/km2 (0.15leks/mile2). Twenty-two percent (9 of 41) of leks active in 1986 were inactive in 1987 (Fig. 5). Twenty-four percent (10 of 42) of leks active in 1987 were inactive in 1988. Twenty-eight leks were active for all 3 years, 9 for 2 years, and 28 for 1 year. The lek disappearance rate was 22.9%, less than the 41.5% disappearance rate estimated by Miller (1984) (X2 = 4.594, f < 0.05). Reproduction Eggs in 41% of all nests hatched (Table 7). Unlike other studies, nest success did not vary with respect to year, age, and nest order (i.e., first nests or renests) (f> 0.05). The mean date for initiation of incubation for successful nests was 15.1 May (n - 30) and for unsuccessful nests 12.9 May (n = 35) (~- 1.057, f - 0.294). Wrangham (1980) suggested that proximity of nests to leks could affect their probability of success. In this study, the distance between each nest and the lek where the particular female was first observed was determined. Successful nests were a mean of 4.58 km (n = 30) and unsuccessful nests 3.20 km (n - 45) from the first lek visited (~ - 1.108, f 0.271). Distance between each nest and the nearest lek was also determined (Fig. 6). Successful nests were a mean of 1.18 km (n = 28) and unsuccessful nests 0.95 km (n = 44) from the nearest lek (~- 1.760, f - 0.083). Successful first nests tended to be further from leks than successful renests; the mean distance for 21 first nests was 1.32 km and for 7 renests was 0.77 km from the nearest lek (~- 3.389, f - 0.002). When nest success was not considered, there was no apparent relationship between time of initiation of incubation and distance to the nearest lek (Fig. 7). The overall mean date for initiating incubation was 13 May. There were no differences in incubation date associated with either age or year (f> 0.05). Adults had a slightly higher tendency to renest which may explain why differences in incubation dates between adults and yearlings were not detected (Fig. 8); 48.3% (n - 89) of first nesters were adults and 62.5% (n = 16) of .renesters were adults (X2 - 1.092, f> 0.05). The mean duration of incubation was 24.4 days (n = 29, SD - 0.6). Adults had a mean of 10 eggs in their first nests (n - 13); yearlings had 8.65 eggs (n - 17) (~= 1.045, f = 0.305). Only first nests were considered in the previous analysis since the mean clutch of 9.23 eggs (n - 30) for a first nest was larger (~ - 3.450, f - 0.001) than the mean clutch of 4.89 eggs (n - 9) for renests. Yearlings did not nest further from the nearest lek than adults (~- 0.253, f 0.801); yearling nests were a mean of 1.01 km (n - 43) and adult nests 0.98 km (n = 38) from the nearest lek (Fig. 9). �88 N o R 47 W i DISPLAY SITES R 46 W ,- ~ -, - ~ -;- ~ - ~ -~ -~ ! , R 45 W - ~ ~ ~ -;- ~ - R 44 W ! ~ -; - -~- ~ ~ ~ , ! T4N T4N T3N T2N T2N T1N T1N R47W R46W R45W R44W o Fig. 4. Colorado 2 4km Display sites of male greater prairie-chickens in northeastern during the early - late spring seasons (IS Feb-IS May) 1986-88. �89 Table 5. Location of display sites for male greater prairie-chickens in northeastern Colorado and the maximum number of males attending each display site during the 1986-88 breeding seasons (a plus sign symbolizes an active lek without an accurate count of males; a minus sign symbolizes a site that was not adequately monitored). Universal Transverse Mercators (Zone 12) Lek 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 # Male attendance Legal location East (m) North (m) Township 707970 709090 709830 710230 710480 710650 711180 711380 711750 712900 713270 714390 714540 714880 715420 715820 715830 716370 716610 716670 717050 717100 717150 717180 717250 717730 717750 717780 717930 718030 718130 718350 718690 718860 719030 719040 719100 719340 719590 719630 719890 719920 720060 720470 720620 720980 721230 721250 721620 721750 721900 722100 722370 722440 722510 4448270 4449010 4447340 4454050 4449370 4454850 4449000 4453280 4450530 4458300 4462440 4464320 4460620 4453420 4454310 4453760 4448010 4453120 4456480 4453840 4455600 4457710 4448870 4454700 4454290 4441630 4451570 4447490 4464480 4448140 4450100 4449920 4453530 4457680 4453800 4440690 4443610 4451710 4464240 4453920 4464190 4449630 .4448250 4456320 4455520 4458240 4455970 4450580 4445270 4461370 4455230 4453700 4463250 4453940 4456230 3N 2N 2N 3N 2N 3N 2N 3N 3N 3N 4N 4N 4N 3N 3N 3N 2N 3N 3N 3N 3N 3N 2N 3N 3N 2N 3N 2N 4N 2N 2N 2N 3N 3N 3N 1N 2N 3N 4N 3N 4N 2N 2N 3N 3N 3N 3N 2N 2N 4N 3N 3N 4N 3N 3N Range 461J 4611 4611 4611 4611 4611 4611 4611 4611 4611 4611 4611 4611 461J 461J 4611 461J 4611 4611 4611 4511 4511 4511 4511 4511 4511 4511 451J 4511 451J 4511 4511 4511 4511 4511 4511 4511 4511 4511 4511 4511 4511 4511 4511 4511 4511 4511 4511 4511 4511 4511 4511 4511 451J 4511 Section 7 5 8 20 5 21 4 28 33 10 27 23 35 25 24 24 12 25 13 24 18 7 7 19 19 31 31 7 19 7 6 6 29 8 20 5 29 32 20 28 21 5 8 16 16 9 16 4 21 34 22 27 27 22 15 Quarter NIJ SII SE SE NE Nil SII NE SE NE NE NE SE NIJ SII SIJ Nil NE NE SE SII SII NIJ Nil SII Nil NE SE NE SE NE NE Nil SIJ SII Nil Nil NE NE SII Nil SE NE Nil SIJ NE SE NE NE NIJ Nil Nil NE SE NE 1986 1987 + 14 3 + 3 5 6 3 6 7 0 14 3 3 0 0 9 0 9 9 2 4 15 0 12 0 0 0 2 0 0 8 8 0 0 0 2 9 0 2 0 + + 5 0 0 2 14 0 0 0 6 0 0 18 2 0 2 6 0 0 + + 18 11 10 14 0 0 5 1 + 0 0 + 1988 8 3 3 5 1 2 17 10 3 2 7 4 10 0 2 5 19 3 10 17 0 12 17 1 12 6 2 0 9 4 15 12 26 8 8 8 19 0 4 0 3 24 0 8 0 16 8 8 3 6 12 14 6 0 0 �90 Table 5. Continued. Universal Transverse Mercators (Zone 12) Lek # 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 Male attendance . Legal location East (m) North (m) Township 722850 723020 723300 723320 723440 723450 723780 724110 724120 724180 724270 724420 724450 724830 724960 725280 725750 725870 726290 726410 726520 726700 727160 727280 727410 727450 727590 727760 728090 728280 728300 728590 728630 728730 728740 728830 728940 729030 729820 730150 730360 730390 730430 730550 730970 731000 731320 732060 732420 732470 733080 734040 734150 734620 734700 735240 735690 4456700 4456460 4458750 4463170 4450180 4455900 4444340 4453510 4454510 4463360 4459920 4449180 4455370 4448130 4447950 4450980 4447080 4445950 4447050 4449940 4455730 4450140 4444880 4444760 4461430 4454630 4456700 4462440 4458320 4447390 4460090 4448100 4448610 4445330 4448260 4464820 4448110 4457150 4466220 4458700 4449870 4446390 4450070 4464090 4455770 4447120 4445470 4462010 4445100 4454660 4446330 4459030 4451990 4459970 4453650 4448720 4456600 3N 3N 3N 4N 2N 3N 2N 3N 3N 4N 3N 2N 3N 2N 2N 3N 2N 2N 2N 2N 3N 2N 2N 2N 4N 3N 3N 4N 3N 2N 3N 2N 2N 2N 2N 4N 2N 3N 4N 3N 2N 2N 2N 4N 3N 2N 2N 4N 2N 3N 2N 3N 3N 3N 3N 2N 3N Range 45101 45101 45101 45101 45101 45101 45101 45101 45101 45101 45101 45101 45101 45101 45101 45101 45101 45101 45101 45101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 44101 Section 15 15 2 26 2 14 23 26 23 26 2 2 23 11 12 36 13 13 13 1 18 6 19 19 31 19 18 30 8 17 5 8 8 20 8 20 8 8 16 9 4 16 4 21 16 16 21 34 22 22 14 2 35 1 25 12 13 Quarter NE NE SIJ NIJ NIJ SIJ SIJ NE SE NE NE SE NE SE SIJ SIJ NIJ SE NE SE SIJ NIJ SE SE NE SE NE SE NIJ NIJ NIJ SIJ NIJ NIJ NIJ NE SE SE NIJ NIJ SIJ SIJ NIJ SE SE NE NE NE SE SE SIJ SE NE NIJ NIJ NIJ NE 1986 1987 1988 4 4 5 5 6 0 0 0 0 2 0 0 4 0 0 0 5 10 0 12 7 7 0 2 2 0 12 9 8 0 6 8 0 6 8 8 0 5 0 2 9 9 9 0 4 6 0 2 4 1 5 0 1 1 13 10 1 14 0 8 10 0 0 1 9 8 10 + + 12 4 0 0 8 9 0 0 7 10 0 0 0 + 2 0 7 0 0 18 0 8 0 10 0 6 4 4 0 + + 7 6 17 9 1 8 0 1 1 0 10 10 8 1 5 2 3 1 26 4 6 9 14 4 6 5 4 0 2 3 8 10 3 1 �91 Table 6. Colorado, Indices 1986-88. of male greater prairie-chicken abundance in northeastern Index 1986 1987 1988 n leks 41 42 47 ~ displaying males/lek 7.11 ± 3.72 7.26 + 4.35 10.66 ± Lek density Leks/km2 Leks/mile2 0.14 0.35 0.14 0.36 0.15 0.40 Displaying male densitya Males/km2 Males/mile2 0.97 2.52 l.02 2.64 l. 69 4.38 aMales displaying 6.46 alone were used in the analysis. Table 7. Success rate and date for initiation of incubation for female greater prairie-chicken nests in northeastern Colorado, 1986-88. Success rate Initiation Category n Year 1986 1987 1988 21 26 32 33.33 42.31 43.75 22 25 36 39 40 4l.03 40.00 Nest order First Renests 64 15 Totals 79 of incubation ~ date SD 12 May 12 May 11 May 15.3 May 11.4 May 12.8 May 11.5 4.8 44 39 11 May 13 May 13 .1 May 12.9 May 9.2 6.6 39.06 46.67 68 15 10 May 25 May 10.1 May 26.3 May 4.2 8.0 40.51 83 12 May 13 .0 May 8.1 Rate (%) n Median date 7.2 Age Adults Yearlings �R_W \D RoMW R«iW N T4N T4N N 1986 8 SIZE OF LEKS TliN T3M 2-5 MALES o 6-10 MALES o 11-15 MALES o >16MALES T2M 8 8 WRAY o , R .• W R .• W R_W 1987 1988 R4fiW T3M 4kn1 , RoMW T4N ·-------~·~·t...~.... O"~. ~ "'1 ' 8 TaM I T4N T4M T4M 2, RoMW R«iW RoMW R«iW , T3N : ....•. j > : 8 T3N [J ····i·· ..... o ~ ~l ~ T2M ( ,..;. :0 ·····i T2N : . ., ..•.. Fig. 5. Distribution of greater ).9.L : .... :... 8 : s R«iW ····~···O;··...:..... , ..... j : Q ~0 0 .O R_W o : ® RoMW prairie-chicken R_W leks in northeastern R«iW Colorado, WRAY RoMW 1968-88. �93 24 ~ UNSUCCESSFUL (n=65) II SUCCESSFUL (n=28) 1.6-2.0 2.0-2.4 20 16 en ~ 12 W Z 8 4 o 0.0-0.4 0.4-0.8 0.8-1.2 1.2-1.6 DISTANCE (KM) Fig. 6. Distances between nest sites and the nearest lek for successful and unsuccessful greater prairie-chicken nests in northeastern Colorado, 1986-88. �94 18 I EARLY (n=48) [] MID (0=25) 15 I LATE (n=6) 12 ~ w 9 z 6 3 o 0.0-0.4 0.4-0.8 0.8-1.2 1.2-1.6 1.6-2.0 2.0-2.4 DISTANCE (KM) Fig. 7. Distances between nest sites and the nearest lek vs. date of nest initia tion (early = 28 Apr - 12 May, mid = 13 - 27 May, late = 28 May - 11 Jun) for greater prairie-chickens in northeastern Colorado, 1986-88. �95 20 ~ ADULTS (1J=44) • YEARLINGS (D =39) 16 en W 12 _J <C ~ W LL 8 4 28 APR • 4 MAY 5 MAY· 12 MAY· 19 MAY· 26 MAY· 11 MAY 18 MAY 25 MAY 1 JUN > 1 JUN DATE OF NEST INITIATION Fig. 8. Colorado, Date of nest initiation 1986-88. for greater prairie-chickens in northeastern �96 16 ~ ADULTS (n=38) II YEARLINGS (n=43) 12 en UJ ....J « 8 ~ UJ u.. 4 o 0.0-0.4 0.4-0.8 0.8-1.2 1.2-1.6 1.6-2.0 2.0-2.4 DISTANCE (KM) Fig. 9. chickens Distances between nest sites and the nearest in northeastern Colorado, 1986-88. lek for greater prairie- �97 Movement Home range size of greater prairie-chickens was estimated by sex and age class for each season (Table 8). Yearling males tended to have larger home ranges than adult males for all but the late summer season (f> 0.05). However, there were small sample sizes of yearlings in each case. For females, the only difference detected was that adults had larger home ranges than yearlings during autumn (~- 2.734, f - 0.739). However, these results require cautious interpretation because of the large number of statistical comparisons. When ages were combined, females had larger home ranges than males during late spring (~~ 2.236, f - 0.027) and autumn (~~ 2.889, f - 0.006). The trends were in the same direction for early summer, late summer, and winter. Season also was associated with differences in home range size (f < 0.05). Males had larger home ranges in winter than in late summer and autumn. Females had smaller home ranges in late summer than in autumn, winter, and late spring, and smaller home ranges in early spring than in late spring. Some differences in home range size apparently were associated with behavior such as brood status of females (Table 9). For example, during late summer, females with broods tended to have larger home ranges than females without broods (!= 1.864, f - 0.072). Habitat Comparisons Comparison of habitat characteristics between observed and available sites for early spring revealed no differences (Table 10). Males were observed in areas with shorter sand sagebrush, grass, and forbs, lesser sand sagebrush cover, and greater blue grama cover (Table 11). Many of these differences appeared to reflect the frequent use of leks by males. Further examination of habitat by time period showed that differences existed in the height of sand sagebrush and forbs, cover of bare ground, grass, sixweeks annual fescue, warm season grass, sand dropseed, corn, and forbs, and species richness (Table 12). In most cases, the differences apparently reflected the regular use of relatively open, over-grazed habitats by males during their morning and evening display periods. Few differences were found between habitat at observed and available sites for late spring (Table 13). Two exceptions were that grasses and forbs were shorter at observed sites. Males were observed in areas with shorter forbs, lesser blue grama and forb cover, and lesser species richness and slope than females (Table 14). Further examination of habitat by time period showed that differences existed in sand sagebrush height, sand sagebrush, grass, cool season grass, needle-and-thread, forb cover, and slope (Table 15). As with early spring, many of these differences appeared to reflect the regular use of lek sites by males, particularly during morning and evening periods. Furthermore, lek site habitat differed dramatically from available habitat in that lek sites had short and sparse cover (Table 16). Lek sites were located on low, over-grazed ridgetops. These data were supported by an additional comparison between permanent (active 1986-88) and temporary (active < 3 years) leks which showed that permanent leks had shorter forbs, greater blue grama cover, and lesser forb cover .and species richness (Table 17). No differences were found between habitat at observed and available sites for early summer (Table 18). Females were observed in areas with taller forbs, greater forb cover, and species richness than males (Table 19). There were no �98 Table 8. Home range size (area within 75% probability contours generated with harmonic means on a grid size of 25 X 25, ha) of greater prairie-chickens in northeastern Colorado, 1986-88. Males Females All Category Ad Yrlg All Ad Yrlg All birds Early spring n Median ~ SO Late spring n Median ~ SO Early summer n Median ~ SO 12 107.9 167.5 164.2 2 535.2 535.2 568.1 14 127.2 220.2 255.9 22 165.0 175.9 97.2 8 134.9 313.6 439.2 30 160.8 212.6 239.3 44 155.5 214.9 241.7 19 91.0 108.0 97.3 6 250.2 401. 2 482.7 25 92.9 178.3 268.3 48 264.5 367.3 307.6 47 276.2 899.6 2671.9 95 266.0 630.6 1900.7 120 232.0 536.4 1703.6 15 160.5 162.4 82.0 5 291.5 377 .4 316.5 20 164.2 216.2 187.5 26 212.3 777.1 2866.2 28 174.5 694.0 1429.4 54 379.1 734.0 2217.6 74 180.5 594.1 1906.1 13 108.1 130.2 109.9 4 122.6 106.7 62.1 17 118.3 124.7 99.4 21 111.8 153.7 129.9 21 121.4 158.5 110.9 42 115.9 156.1 119.3 59 118.3 147.0 114.0 10 111.3 121.8 87.9 4 213.1 210.6 95.7 14 127.5 147.2 95.9 14 397.3 469.5 342.5 16 114.0 191.2 178.1 30 289.2 321.1 298.2 44 186.7 265.7 263.6 9 208.2 226.4 105.6 4 260.1 242.5 126.9 13 221.1 231.4 107.3 16 244.1 448.5 538.3 7 236.4 261.4 144.8 23 239.4 391.5 459.4 36 237.9 333.7 377.8 Late summer n Median z SO Autumn n Median ~ SO Winter n Median ~ SO �99 Table 9. Home range size (area within 75% probability contours generated with harmonic means, ha) of female greater prairie-chickens with and without broods in northeastern Colorado during late summer, 1986-88. Category With broods n 19 212.3 194.1 139.6 Median ~ SD Without broods All females 23 108.6 124.7 91.1 42 115.9 156.1 114.1 Table 10. Habitat at observed and available locations of greater prairie-chickens in northeastern Colorado during early spring (15 Feb Mar) 1986-88. Observed Habitat variable ~ (36) SO Available ~ - 31 f (36) SD Lax .t 3.17 2.87 3.15 2.52 0.438 0.972 Height, cm Sand sagebrush Grass Forbs 59.31 95.42 57.50 40.27 37.95 44.33 66.53 97.22 60.00 35.19 24.94 37.34 0.429 0.015 0.315 0.421 0.812 0.797 Cover, % Bare Sand sagebrush Grass Cool season grass Needle-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 29.72 8.47 65.56 18.19 16.53 l. 53 50.97 15.69 11.11 10.00 4.31 2.22 18.93 10.27 19.23 16.39 16.47 3.55 16.98 15.31 12.82 12.87 12.54 4.22 29.72 7.78 63.19 20.00 17.08 2.64 46.11 12.92 15.83 6.67 3.33 4.31 18.59 9.74 20.43 18.78 16.10 7.61 16.00 12.33 16.06 9.18 11.65 5.37 0.915 0.757 0.722 0.425 0.894 0.000 0.726 0.204 0.188 0.049 0.664 0.159 1.000 0.769 0.615 0.665 0.885 0.430 0.215 0.399 0.172 0.211 0.734 0.071 1l.03 5.73 12.17 5.11 0.504 0.377 l. 50 l. 56 2.28 2.39 0.014 0.107 Height-density-index, Species richness, Slope, degrees n em �100 Table 11. Habitat at locations prairie-chickens in northeastern Mar) 1986-88. of radio-marked male and female greater Colorado during early spring (15 Feb - 31 Males Habitat variable ~ (18) SD Females ~ (18) f SD Imax .t 2.51 3.48 3.83 1. 99 0.027 0.173 Height, em Sand sagebrush Grass Forbs 44.17 74.44 39.44 32.10 38.07 38.04 74.44 116.39 75.56 42.70 24.18 43.69 0.249 0.070 0.574 0.022 0.000 0.012 Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 31.11 4.44 67.22 22.22 19.72 2.50 50.56 22.50 7.50 10.00 2.50 1. 39 17.95 5.39 17.84 18.25 18.43 4.62 17.23 16.56 8.27 12.00 10.61 2.87 28.33 12.50 63.89 14.17 13.33 0.56 51. 39 8.89 14.72 10.00 6.11 3.06 20.29 12.40 20.90 13.64 14.04 1. 62 17.22 10.51 15.57 14.04 14.30 5.18 0.619 0.001 0.521 0.240 0.272 0.000 0.999 0.069 0.013 0.526 0.228 0.020 0.666 0.019 0.610 0.143 0.250 0.107 0.885 0.006 0.094 1.000 0.396 0.243 9.83 5.28 12.22 6.05 0.581 0.216 1.17 1.04 1. 83 1.92 0.016 0.206 Height-density-index, Species richness, Slope, degrees n cm �101 Table 12. Habitat at locations of radio-marked greater prairie-chickens in northeastern Colorado during morning, afternoon, and evening periods during early spring (15 Feb - 31 Mar) 19S6-SS. Significant differences (f < 0.05) between means for each habitat variable are indicated by different superscripts. Morning Habitat variable Height-density-index, cm Height, cm Sand sagebrush Grass Forbs Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs Species Slope, richness, degrees n (12) (12) Evening (12) SD SD so 1. 94 3.77 2.52 S9.SSa,b 90.S3a 49.17a 45.30 44.15 40.61 21. 2Sa 10.42a 71.67a 14.17a 10.00a 3.7Sa S9.SSa 17.S0a 17.0sa 10.S3a 12.0S 13.05 13.20 13.62 12.61 4. S2 15.59 19.36 16.SS 15.20 77.0Sa 10S.00a S6.2Sb 3.26 27.92a,b 7.0Sa 67.S0a,b 21.67a 21.67a O.OOb 50.42a,b 14.SSa 12.0Sa 12.0sa O.OOa 4.Ssa 4.SS 14.0Sa O.OOa 1. 67a,b Afternoon 1. 29 30.41 34.1S 36.44 41. 2Sb 90.42a 37.0Sa 3S.50 36.27 42.93 22.00 S .11 24.73 20.26 20.26 40.00b 7.92a 57. SOb lS.7Sa 17.92a O. S3a,b 42.92b lS.00a 4.17b 7.0Sa 12.92b 0.42b 17.71 9.64 16.58 15.09 14.69 2.89 14.22 15.23 5.15 8.38 19.48 1. 44 17.90 11.57 11.37 14.53 S.S2 5.21 5.24 1.40 1. 78 �102 Table 13. Habitat at observed and available locations of greater prairie-chickens in northeastern Colorado during late spring (1 Apr 1986-88. Observed Habitat variable ~ Height-density-index, cm (36) SO Available ~ - (36) 15 May) f so Lnax ! 3.56 3.73 4.62 6.53 0.001 0.402 Height, cm Sand sagebrush Grass Forbs 55.28 76.94 45.28 42.83 34.61 40.32 66.67 97.92 67.50 28.74 23.71 36.95 0.021 0.028 0.608 0.190 0.004 0.017 Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 29.72 9.03 60.56 23.89 17.22 5.00 41.39 14.86 7.22 6.25 2.50 7.50 23.69 10.54 24.17 18.86 16.10 8.28 19.66 16.88 7.22 7.40 7.32 13.86 24.58 6.39 65.56 28.19 20.56 7.92 43.47 11.25 11.39 10.00 0.14 8.89 20.89 8.75 23.57 22.81 21.77 11.49 17.40 14.51 10.11 10.82 0.83 9.42 0.460 0.275 0.883 0.266 0.079 0.057 0.472 0.375 0.049 0.028 0.000 0.025 0.332 0.252 0.377 0.386 0.463 0.221 0.636 0.334 0.049 0.091 0.062 0.621 12.92 7.58 15.33 6.45 0.341 0.150 1.97 1.68 3.06 3.09 0.001 0.070 Species richness, Slope, degrees n �103 Table 14. Habitat at locations prairie-chickens in northeastern 1986-88. of radio-marked male and female greater Colorado during late spring (1 Apr - 15 May) Males Habitat variable X Height-density-index, cm (18) SD Females X (18) f SD Emax ! 3.09 4.87 4.04 2.11 0.001 0.453 Height, em Sand sagebrush Grass Forbs 47.78 72.50 26.94 39.79 38.74 32.95 62.78 81. 39 63.61 45.54 30.38 39.36 0.584 0.326 0.471 0.300 0.449 0.005 Cover, % Bare Sand sagebrush Grass Cool season grass Needle-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 31. 39 8.89 61. 67 19.72 14.17 4.44 46.39 22.50 6.39 7.78 2.22 2.50 22.28 10.79 22.94 12.42 12.75 5.66 18.21 18.65 7.44 7.71 6.69 5.22 28.06 9.17 59.44 28.06 20.28 5.56 36.39 7.22 8.06 4.72 2.78 12.50 25.56 10.61 25.95 23.27 18.75 10.42 20.28 10.74 7.10 6.96 8.08 17.76 0.578 0.946 0.618 0.013 0.122 0.016 0.663 0.029 0.851 0.677 0.444 0.000 0.679 0.938 0.787 0.192 0.261 0.694 0.129 0.006 0.496 0.221 0.824 0.033 10.22 6.49 15.61 7.81 0.452 0.031 1.06 1.11 2.89 1. 68 0.098 0.001 Species richness, Slope, degrees n �104 Table 15. Habitat at locations of radio-marked greater prairie-chickens in northeastern Colorado during morning, afternoon, and evening periods during late spring (1 Apr - 15 May) 1986-88. Significant differences (f < 0.05) between means for each habitat variable are indicated by different superscripts. Morning (12) Habitat variable & SD Afternoon (12) & SD Evening (12) R SD 2.34a 1.93 5.634 5.16 2.72a 2.64 Height, cm Sand sagebrush Grass Forbs 49.584 67.08a 32.08a 29.88 26.24 40.75 87.08b 92.50a 64.17a 43.61 34.01 44.36 29.17a 71.25a 39.58a 34.03 39.49 30.49 Cover, % Bare Sand sagebrush Grass Cool season grass Needle-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 24.174 6.254 72.084 35.424 27.504 6.254 45.004 18.334 7.084 8.75a O.Ooa 1.674 13.62 7.11 13.89 22.81 17.90 10.90 14.77 14.20 4.98 9.56 0.00 3.26 30.424 16.25b 53.33b 19.17b 12.92b 4.58a 37.504 7.924 9.58a 5.83a 3.33a 11.67b 26.92 12.99 25.08 14.75 13.22 8.11 18.40 10.97 9.64 5.15 8.07 15.57 34.58a 4.58a 56.25a,b 17.08b 11.25b 4.17a 41. 67a 18.33a 5.00a 4.17a 4.1]4 9.17a,b 28.56 6.89 28.53 13.22 12.45 5.57 25.35 22.50 6.03 6.69 9.73 17.30 Species richness, n 11.42a 4.93 15.08a 7.75 12.25a 9.52 1.67a 1.72 3.08b 1.62 1.17a 1.11 Height-density-index, Slope, degrees cm �105 Table 16. Habitat at observed and available lek locations for greater prairie-chickens in northeastern Colorado during late spring (1 Apr - 15 May) 1986-88. Observed Habitat variable ~ SD Available ~ (36) ~ SD Lnax .£ 1.04 0.77 3.00 2.17 0.000 0.000 Height, cm Sand sagebrush Grass Forbs 38.46 67.38 53.08 24.65 31.66 42.72 58.15 94.31 63.23 34.49 30.67 40.58 0.008 0.800 0.682 0.000 0.000 0.167 Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 30.92 2.77 66.62 26.85 16.77 6.85 43.69 22.62 8.15 6.31 0.31 2.00 12.40 3.75 12.57 16.76 13.09 8.32 16.85 17.35 9.75 7.41 2.48 4.98 21. 31 4.92 72.38 30.23 21. 62 7.92 48.54 14.85 16.54 8.85 1.15 6.15 15.87 6.22 15.57 20.68 17.37 12.90 16.43 14.71 15.48 11.48 5.36 8.42 0.051 0.000 0.089 0.095 0.025 0.001 0.844 0.190 0.000 0.001 0.000 0.000 0.000 0.019 0.022 0.307 0.075 0.573 0.099 8:007 0.000 0.137 0.251 0.001 11.62 5.60 14.29 5.74 0.847 0.008 0.45 0.73 2.05 1. 98 0.000 0.000 Height-density-index, Species richness, Slope, degrees n cm (36) �106 Table 17. Habitat at permanent (active in 1986-88) and temporary (inactive for at least 1 year) 1ek locations for greater prairie-chickens in northeastern Colorado during late spring (1 Apr - 15 May). Permanent Habitat (28) Temporary so variable Height-density-index, cm (37) so Lax 0.88 0.67 1.16 0.83 0.254 0.148 Height, cm Sand sagebrush Grass Forbs 33.21 58.93 28.93 20.29 27.26 28.23 42.43 73.78 71.35 27.10 33.57 43.01 0.122 0.265 0.026 0.137 0.061 0.000 Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 31.43 3.57 66.96 26.07 18.57 7.14 44.82 28.21 6.07 6.25 0.00 0.71 12.01 4.48 11.97 13.43 10.70 7.13 16.47 15.59 8.96 6.18 0.00 2.24 30.54 2.16 66.35 27.43 15.41 6.62 42.84 18.38 9.73 6.35 0.54 2.97 12.84 3.01 13.16 19.06 14.64 9.21 17.30 17.60 10.13 8.30 3.29 6.18 0.724 0.027 0.615 0.062 0.095 0.170 0.800 0.517 0.512 0.115 0.000 0.778 0.158 0.847 0.749 0.338 0.805 0.642 0-.022 0.135 0.957 0.324 0.046 9.61 3.34 13 .14 6.48 0.001 0.006 0.39 0.57 0.49 0.84 0.039 0.593 Species richness, Slope, degrees n �107 Table 18. Habitat at observed and available locations of greater prairie-chickens in northeastern Colorado during early summer (16 May Jun) 1986-88. Observed Habitat variable ~ Height-density-index, SO Available ~ (36) ~ SO Enax .t 4.09 4.07 2.94 1.77 0.000 0.128 Height, cm Sand sagebrush Grass Forbs 64.86 91. 25 68.19 38.81 33.35 36.76 54.03 84.03 69.58 41. 28 42.34 44.50 0.717 0.163 0.263 0.255 0.424 0.886 Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 22.22 5.97 67.08 32.36 17.92 10.83 43.61 13 .06 7.22 6.53 3.06 13.33 21. 30 7.54 24.42 24.83 17.50 10.79 18.88 14.99 7.79 8.35 10.57 17.24 29.44 5.14 60.69 28.06 16.94 7.78 41. 67 10.14 5.56 10.56 2.78 11.39 27.85 6.15 29.64 26.73 18.91 12.73 22.04 13.76 8.93 13.82 8.40 17.01 0.117 0.233 0.256 0.664 0.649 0.333 0.365 0.615 0.423 0.004 0.179 0.939 0.221 0.609 0.322 0.481 0.822 0.276 0.689 0.393 0.401 0.140 0.902 0.632 Species 20.69 8.90 16.75 8.75 0.919 0.062 1. 58 1. 25 1.81 2.03 0.005 0.578 richness, Slope, degrees n cm (36) - 30 �108 Table 19. Habitat at locations prairie-chickens in northeastern Jun) 1986-88. of radio-marked male and female greater Colorado during early summer (16 May - 30 Males Habitat variable ~ Height-density-index, cm (18) SO Females ~ (18) £ SO Lax .t 4.93 5.46 3.25 1.71 0.000 0.227 Height, cm Sand sagebrush Grass Forbs 53.06 83.06 51.11 43.66 36.18 35.59 76.67 99.44 85.28 30.00 28.95 29.97 0.132 0.367 0.487 0.067 0.143 0.004 Cover, % Bare Sand sagebrush Grass Cool season grass Needle-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 26.67 5.56 66.67 32.22 18.89 8.06 42.50 14.72 7.22 6.39 6.11 7.22 28.08 7.65 25.90 24.45 17.95 7.88 18.49 16.31 6.69 9.04 14.51 12.97 17.78 6.39 67.50 32.50 16.94 13.61 44.72 11.39 7.22 6.67 0.00 19.44 10.18 7.63 23.59 25.91 17.50 12.70 19.74 13.81 8.95 7.86 0.00 19.09 0.000 0.993 0.705 0.814 0.918 0.057 0.791 0.499 0.241 0.569 0.121 0.220 0.746 0.920 0.974 0.744 0.124 0.730 0.513 1.000 0.922 0.092 0.031 15.33 8.76 26.06 5.06 0.029 0.000 1.61 1.14 1. 56 1. 38 0.446 0.896 Species richness, Slope, degrees n �109 differences associated with time period (Table 20). Some differences between males and females may have related to selection by females of nesting areas while males were still frequenting leks. Examination of observed and available habitat at nests sites showed that observed sites had greater height-density-index, taller sand sagebrush and grass, lesser bare cover and slope, and greater sand sagebrush, grass, and prairie sandreed cover (Table 21). Nests within 1 km of leks had shorter sand sagebrush and forbs and less species richness (Table 22). Despite the fact that nests generally were in areas with relatively dense, tall cover, successful nests differed little from failed nests (Table 23). In addition, few differences in habitat were detected for either age (adults and yearlings) (Table 24) or nest order (first nests and renests) (Table 25). Comparison of habitat characteristics between observed and available sites for late summer revealed essentially no differences (Table 26). Likewise, comparison of habitat by sex (Table 27) and period (Table 28) also failed to reveal any differences. One possible reason for the lack of differences may be that most birds used relatively extensive and homogenous areas of sand sagebrush and grass cover. During autumn, observations of greater prairie-chickens suggested that many birds were moving closer to agricultural areas, even though they were rarely found feeding in them. Habitat comparisons between observed and available sites supported this suggestion (Table 29). Greater prairie-chickens were observed in areas with denser and taller sand sagebrush, less bare ground and corn cover, and greater species richness. No differences were detected when observations were divided by sex (Table 30) or period (Table 31). Although differences in habitat generally were not detected between males and females for early summer - autumn (16 May - 31 Oct), numerous differences occurred among habitat variables at locations of brood females and non-brood females (Table 32). Broods used areas with greater height-density-index and species richness, and taller sand sagebrush, grass, and forbs. Essentially no differences were detected between observed and available habitat for winter (Table 33). Likewise, habitat for males and females did not differ (Table 34). Since greater prairie-chickens are frequently in large mixed-sex flocks during winter, lack of sex differences in habitat possibly should be expected. However there were several differences apparently associated with diurnal patterns of behavior (Table 35). For example, afternoon habitat generally had greater height-density-index and slope, taller grass, and less corn and forb cover. Some differences may represent afternoon loafing habitat and morning and evening foraging habitat in corn fields (Table 35). Habitat Description The study area was classified and mapped into 10 general habitat types (Fig. 10). Mapping revealed that 85.23% of the study area consisted of rangeland. However, only 16.61% of the area was classified as good-quality rangeland (mid-tall grass or sage/mid-tall grass). Additional classification of the area into 45 specific habitat types (Figs. 11-14, Table 36) revealed that most habitat types were delineated by units of management (i.e., they were frequently bordered by fences and managed with different intensities and types of grazing pressure or agriculture). Numerous plant species were found throughout the study (Table 37). Habitat types recognized were: �110 Table 20. Habitat at locations of radio-marked greater prairie-chickens in northeastern Colorado during morning, afternoon, and evening during early summer (16 May - 30 Jun) 1986-88. None of the differences was significant. Morning (12) Habitat variable Height-density-index, cm Afternoon (12) SD Evening (12) SD SD 3.17 l. 95 4.12 2.75 4.98 6.30 Height, cm Sand sagebrush Grass Forbs 66.67 90.00 83.75 38.40 25.50 4l.40 73.33 100.42 65.83 33.26 2l.47 24.29 54.58 83.33 55.00 44.90 47.59 39.20 Cover, % Bare Sand sagebrush Grass Cool season grass Needle-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 22.50 4.58 73.33 37.50 26.25 14.17 45.00 12.92 5.42 6.25 2.50 8.75 17.77 5.42 19.23 29.58 2l.86 14.28 17.32 15.73 3.34 9.08 8.66 7.72 15.83 6.67 70.83 33.33 13.33 10.83 48.33 14.58 8.33 7.50 0.00 16.25 12.76 7.78 19.17 19.58 12.49 9.25 18.38 14.05 6.85 8.66 0.00 14.16 28.33 6.67 57.08 26.25 14.17 7.50 37.50 1l.67 7.92 5.83 6.67 15.00 29.64 9.37 3l.51 25.15 15.05 7.54 20.73 16.28 11.37 7.93 16.00 25.50 Species richness, D 22.17 8.02 22.83 6.60 17.08 11.07 l.42 l.08 2.17 l. 53 l.17 0.94 Slope, degrees �ill Table 21. Habitat at observed and available nest locations prairie-chickens in northeastern Colorado, 1986-88. Observed Habitat variable 1i (87) SD Available 1i for greater (87) f SD Lax .t. 5.85 2.59 3.06 l. 97 0.012 0.000 83.79 111.32 82.64 29.69 16.49 34.20 71.32 102.24 75.57 33.95 22.71 34.32 0.216 0.003 0.973 0.011 0.003 0.175 Cover, % Bare Sand sagebrush Grass Cool season grass Needle-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 11.44 13.74 72.87 36.26 26.61 9.60 44.20 10.17 10.52 12.41 0.17 15.34 7.15 9.80 15.82 21.09 19.16 11.42 17.34 10.77 11.23 10.59 l.19 12.12 21.72 6.78 66.21 31.67 21. 95 9.02 40.57 10.06 7.53 9.14 0.17 12.70 15.90 7.11 18.03 20.82 18.67 11. 20 18.54 11.70 11.43 10.15 l.19 10.61 0.000 0.003 0.229 0.650 0.809 0.860 0.534 0.443 0.870 0.696 1.000 0.220 0.000 0.000 0.010 0.143 0.106 0.738 0.185 0.946 0.084 0.039 1.000 0.128 Species 23.15 6.11 21.94 6.22 0.868 0.198 l. 63 1. 57 2.66 2.96 0.000 0.005 Height-density-index, cm Height, cm Sand sagebrush Grass Forbs richness, Slope, degrees II �112 Table 22. Habitat at greater prairie-chicken nest sites vs. distance each nest and the nearest 1ek in northeastern Colorado, 1986-88. < 1 Habitat variable kIn ~ (45) > 1 SO ~ kIn (42) between f so !:max .t 5.59 2.79 6.12 2.37 0.290 0.342 75.56 109.89 75.11 33.65 18.60 31.42 92.62 112.86 90.71 21. 90 13.93 35.57 0.006 0.064 0.419 0.006 0.400 0.033 Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 11.22 12.44 75.00 39.00 28.89 9.89 44.11 10.67 10.11 11.00 0.00 13.00 7.62 10.64 16.20 22.73 19.54 12.41 17.81 11. 90 10.42 8.96 0.00 10.89 11.67 15.12 70.60 33.33 24.17 9.29 44.29 9.64 10.95 13.93 0.36 17.86 6.69 8.73 15.27 19.02 18.67 10.39 17.02 9.52 12.16 12.02 1. 71 12.98 0.399 0.204 0.704 0.252 0.773 0.255 0.771 0.153 0.315 0.057 0.255 0.774 0.205 0.196 0.212 0.253 0.807 0.963 0.660 0.·729 0.199 0.183 0.061 Species 21. 53 5.18 24.88 6.60 0.118 0.010 1.49 1. 38 1. 79 1. 76 0.110 0.382 Height-density-index, cm Height, cm Sand sagebrush Grass Forbs richness, Slope, degrees n �113 Table 23. Habitat at successful and unsuccessful nest sites prairie-chickens in northeastern Colorado, 1986-88. Successful Habitat variable ~ Height-density-index, cm (29) SO Failed ~ for greater (40) f SO Imax ! 5.31 1. 85 6.09 2.57 0.073 0.167 81.03 113.28 90.52 32.41 15.77 33.09 85.63 108.63 80.88 27.08 15.93 33.80 0.296 0.969 0.921 0.525 0.234 0.242 Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 12.76 11.21 73.28 35.34 29.14 5.52 44.48 8.97 12.52 14.66 0.00 17.24 7.74 7.87 15.13 22.68 22.56 8.38 15.02 9.20 12.27 12.24 0.00 12.65 10.88 16.38 73.63 40.13 27.13 11.75 42.50 10.75 10.75 11.63 0.25 12.50 6.78 10.50 17.32 20.89 18.84 12.53 18.67 11.69 11.41 10.15 1. 58 10.06 0.439 0.114 0.460 0.628 0.295 0.029 0.232 0.189 0.665 0.277 0.185 0.287 0.029 0.931 0.369 0.688 0.016 0.639 0.497 0.936 0.266 0.324 0.087 Species 25.00 6.03 22.43 5.95 0.926 0.082 2.07 1. 75 1. 23 1. 27 0.064 0.032 Height, cm Sand sagebrush Grass Forbs Slope, richness, degrees n �114 Table 24. Habitat at nests sites for adult and yearling prairie-chickens in northeastern Colorado, 1986-88. Adults Habitat variable ~ Height-density-index, cm Height, cm Sand sagebrush Grass Forbs Cover, % Bare Sand sagebrush Grass Cool season grass Needle-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs Species Slope, richness, degrees n (43) Yearlings SD ~ female greater (44) f SD Emax ~ 5.92 2.28 5.78 2.90 0.122 0.798 8l.16 112.67 78.60 30.80 16.99 35.23 86.36 110.00 86.59 28.68 16.07 33.09 0.643 0.718 0.685 0.417 0.453 0.279 10.70 12.21 75.93 40.70 31.05 10.93 44.30 10.93 12.21 13.95 0.35 14.42 7.04 8.82 17.60 21.42 17.58 13.15 17.17 10.76 11.46 9.79 1. 69 13.68 12.16 15.23 69.89 31. 93 22.27 8.30 44.09 9.43 8.86 10.91 0.00 16.25 7.27 10.56 13 .40 20.06 19.84 9.40 17.69 10.85 10.88 11.22 0.00 10.46 0.836 0.244 0.079 0.670 0.435 0.031 0.846 0.959 0.737 0.380 0.083 0.343 0.152 0.075 0.052 0.032 0.287 0.955 0.520 0.166 0.182 0.183 0.484 21. 91 6.96 24.36 4.93 0.027 0.062 1. 53 1.44 1. 73 1. 70 0.272 0.571 �us Table 25. Habitat at first and second nesting attempts within a single in northeastern Colorado, breeding season by female greater prairie-chickens 1986-88. First Habitat variable ~ Height-density-index, cm Height, cm Sand sagebrush Grass Forbs Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs Species richness, Slope, degrees n (73) SD Second ~ z (14) SD Lax .t 6.05 2.69 4.81 1.71 0.073 0.102 86.71 111.44 85.68 28.76 16.61 34.10 68.57 110.71 66.79 30.85 16.39 31. 23 0.667 1.000 0.763 0.035 0.881 0.058 11.16 14.79 72.81 35.89 26.30 10.48 44.79 9.93 10.82 11.85 0.21 15.48 6.85 10.02 15.90 20.45 19.15 11.91 17.11 10.52 11.58 10.26 1. 30 12.22 12.86 8.21 73.21 38.21 28.21 5.00 41.07 11.43 8.93 15.36 0.00 14.64 8.71 6.39 16.01 24.93 19.87 7.07 18.83 12.31 9.44 12.16 0.00 12.00 0.201 0.074 0.896 0.288 0.786 0.040 0.579 0.392 0.420 0.356 1.000 0.420 0.021 0.931 0.708 0.734 0.027 0.465 0.637 0.567 0.259 0.182 0.815 23.32 5.96 22.29 7.01 0.377 0.567 1. 66 1. 63 1. 50 1. 22 0.247 0.733 �116 Table 26. Habitat characteristics at observed use and available locations of greater prairie-chickens in northeastern Colorado during late summer (1 Ju1 15 Aug), 1986-88. Observed Habitat cm Height, cm Sand sagebrush Grass Forbs Cover, % Bare Sand sagebrush Grass Cool season grass Needle-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs richness, Slope, degrees Available SD variable Height-density-index, Species (36) n (36) SD Lax 4.97 4.35 3.81 3.17 0.064 0.200 53.06 101. 53 65.00 30.57 25.43 30.52 46.11 96.81 57.08 28.84 23.43 29.94 0.732 0.629 0.910 0.325 0.415 0.270 14.31 10.14 73.19 32.36 22.64 10.69 50.83 13.75 7.08 14.31 1. 81 13.61 8.71 10.72 15.91 18.11 16.28 10.01 16.01 9.44 7.21 10.63 5.23 10.32 18.47 6.81 71.25 30.83 23.33 6.11 48.47 14.72 8.33 12.64 0.56 12.78 12.41 7.09 18.84 18.34 17.77 7.08 18.39 12.70 8.78 11.31 1.59 12.79 0.040 0.016 0.322 0.939 0.607 0.044 0.416 0.083 0.247 0.719 0.000 0.211 0.104 0.125 0.638 0.723 0.863 0.029 0.563 0.714 0.511 0.522 0.178 0.762 21. 06 5.04 19.00 4.70 0.687 0.078 2.67 2.67 3.03 3.31 0.212 0.612 �117 Table 27. Habitat characteristics at locations of radio-marked male and in northeastern Colorado during late summer female greater prairie-chickens Jul - 15 Aug), 1986-88. Males Habitat variable ~ Height-density-index, cm Height, cm Sand sagebrush Grass Forbs Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs Species richness, Slope, degrees n (18) SD Females R (18) (1 f SD Emax .t 4.96 5.40 4.98 3.14 0.032 0.991 53.89 108.33 7l. 94 36.56 29.61 32.46 52.22 94.72 58.06 24.21 18.90 27.61 0.098 0.073 0.512 0.873 0.109 0.176 13.61 7.50 75.00 34.44 23.61 10.28 5l.11 13.33 5.56 12.50 l. 39 14.44 8.54 7.52 14.45 18.78 17.64 10.36 16.41 10.43 5.39 10.33 4.13 11.23 15.00 12.78 71.39 30.28 2l. 67 11.11 50.56 14.17 8.61 16.11 2.22 12.78 9.07 12.86 17.47 17.70 15.24 9.93 16.08 8.62 8.54 10.92 6.24 9.58 0.806 0.033 0.442 0.810 0.554 0.866 0.934 0.439 0.066 0.820 0.099 0.520 0.639 0.144 0.504 0.498 0.726 0.807 0.919 0.795 0.208 0.315 0.640 0.635 2l. 33 4.41 20.78 5.71 0.293 0.746 2.61 2.91 2.72 2.49 0.527 0.903 �118 Table 28. Habitat characteristics at locations of radio-marked greater prairie-chickens in northeastern Colorado during morning, mid-day, and evening during late summer (1 Ju1 - 15 Aug), 1986-88. None of the differences was significant. Morning Habitat cm Height, cm Sand sagebrush Grass Forbs Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs richness, Slope, degrees Afternoon SD variable Height-density-index, Species (12) n (12) Evening (12) so SD 4.31 2.51 6.28 6.35 4.32 3.28 54.58 102.50 57.50 32.71 19.13 25.54 54.17 110.42 76.67 34.10 34.14 31. 79 50.42 91. 67 60.83 27.01 18.26 32.74 15.00 12.50 72.50 32.92 25.00 10.00 51. 25 14.58 7.50 14.58 3.33 14.17 10.44 12.15 17.52 14.37 16.10 9.77 17.60 7.22 8.39 12.33 7.49 11.25 12.92 11.67 72.08 30.83 21.25 7.50 49.17 14.58 7.08 13.75 1. 25 13.75 6.89 13.03 19.24 19.75 17.73 8.39 16.35 12.33 8.38 9.80 4.33 8.56 15.00 6.25 75.00 33.33 21. 67 14.58 52.08 12.08 6.67 14.58 0.83 12.92 9.05 4.83 11.08 21. 03 16.14 11.17 15.29 8.65 4.92 10.54 2.89 11.77 19.08 4.23 22.33 5.16 21. 75 5.45 1. 92 1. 31 2.42 2.07 3.67 3.87 �119 Table 29. Habitat characteristics at observed use and available locations of greater prairie-chickens in northeastern Colorado during autumn (16 Aug - 31 Oct), 1986-88. Observed (36) Habitat variable R Available (36) £ SD R SD 8.05 14.09 15.03 25.05 0.001 0.151 48.19 100.69 58.19 29.23 34.97 32.27 29.31 115.97 54.72 29.62 55.93 35.13 0.938 0.007 0.619 0.008 0.170 0.664 Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 17.36 8.47 71.39 2l.81 12.08 5.14 58.89 10.97 15.97 11.67 2.22 14.31 10.92 10.27 16.72 16.87 13.70 7.51 14.69 13.30 14.87 13.31 10.45 12.77 20.83 3.06 72 .22 17.08 15.42 2.78 6l.25 12.22 10.56 8.61 12.36 10.00 11.98 4.97 15.97 18.80 17.94 5.40 16.96 17.17 12.47 13.23 24.48 10.14 0.586 0.000 0.787 0.525 0.115 0.055 0.400 0.135 0.301 0.974 0.000 0.178 0.203 0.006 0.829 0.266 0.379 0.130 0.530 0.731 0.098 0.332 0.027 0.118 Species richness, n 17.83 6.10 14.14 7.69 0.175 0.027 2.58 3.73 2.44 3.31 0.481 0.868 Height-density-index, cm Height, cm Sand sagebrush Grass Forbs Slope, degrees Emu ! �120 Table 30. Habitat characteristics at locations of radio-marked male and female greater prairie-chickens in northeastern Colorado during autumn (16 Aug - 31 Oct). 1986-88. Males Habitat variable (18) Females £nax 4.19 2.04 0.000 0.109 32.19 44.07 37.51 47.22 98.61 56.11 26.86 23.81 26.98 0.463 0.015 0.185 0.845 0.727 0.704 18.06 8.06 71. 39 16.67 6.39 3.61 60.83 10.83 16.39 9.44 4.44 12.22 13 .19 9.72 17.64 16.18 8.88 7.44 14.48 13.75 17.72 13.38 14.64 11.27 16.67 8.89 71. 39 26.94 17.78 6.67 56.94 11.11 15.56 13.89 0.00 16.39 8.40 11.06 16.25 16.37 15.46 7.48 15.06 13.23 11.87 13.23 0.00 14.12 0.071 0.602 0.739 0.962 0.028 0.983 0.872 0.878 0.108 0.964 0.362 0.709 0.812 1.000 0.067 0.012 0.227 0.435 0.951 0.869 0.324 0.215 0.335 16.39 6.74 19.27 5.17 0.283 0.159 1. 67 1. 78 3.50 4.87 0.000 0.148 SO ~ 11.92 19.32 49.17 102.78 60.28 Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs Species cm Height. cm Sand sagebrush Grass Forbs richness, Slope. degrees II f so ~ Height-density-index. (18) ~ �121 Table 31. Habitat characteristics at locations of radio-marked greater prairie-chickens in northeastern Colorado during morning, mid-day, and evening during autumn (16 Aug - 31 Oct), 1986-88. None of the differences was significant. Morning (12) so Habitat variable , Evening (12) so so 3.17 2.32 13.88 22.50 7.11 7.51 Height, cm Sand sagebrush Grass Forbs 35.42 92.08 43.75 24.35 25.54 25.77 53.33 118.33 67.92 28.39 45.14 35.45 55.83 91.67 62.92 32.39 26.31 32.22 Cover, % Bare Sand sagebrush Grass Cool season grass Needle-and-thread Sixweeks annual fescue Warm season grass Blue grama . Sand dropseed Prairie sandreed Corn Forbs 17.08 7.08 70.42 21.25 17.92 4.17 56.67 11.25 16.67 16.25 0.00 18.33 13.73 10.10 18.27 17.47 18.02 5.15 14.51 14.48 10.94 15.54 0.00 14.67 20.83 7.92 70.00 23.33 7.50 5.42 57.08 10.00 10.42 10.00 6.67 10.83 9.73 11.17 15.81 18.38 10.55 8.65 14.22 14.30 14.53 8.53 17.75 11.84 14.17 10.42 73.75 20.83 10.83 5.83 62.92 11.67 20.83 8.75 0.00 13.75 8.48 10.10 17.21 16.07 9.96 8.75 15.73 12.12 17.69 14.64 0.00 11.51 17.92 7.62 18.83 5.44 16.75 5.31 2.33 2.84 3.67 5.61 1. 75 1.60 Height-density-index, I Afternoon (12) Species richness, Slope, degrees n cm �122 Table 32. Habitat characteristics at locations of radio-marked female greater prairie-chickens with and without broods in northeastern Colorado during early summer - autumn (16 May - 31 Oct). 1986-88. Brood (48) Habitat variable ~ SD No brood (56) R ~ SD Lax t 4.78 2.69 3.54 1.91 0.015 0.009 69.17 103.33 74.17 28.48 23.60 26.74 52.95 88.93 55.18 34.62 25.93 32.61 0.172 0.510 0.166 O.Oll 0.004 0.002 Cover. % Bare Sand sagebrush Grass Cool season grass Needle-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 14.69 10.63 73.33 29.79 18.23 9.27 53.75 11.15 12.81 11.15 0.83 15.94 8.72 10.70 16.22 21.88 16.87 10.96 17.67 12.04 ll.80 10.22 3.90 11.97 18.04 8.04 69.46 29.38 19.46 7.41 49.02 11.25 9.55 11.96 5.27 13.57 12.53 9.37 18.77 20.25 19.13 9.63 18.35 12.87 11.41 13.54 17.04 17.70 0.012 0.344 0.307 0.578 0.378 0.353 0.795 0.642 0.807 0.050 0.000 0.007 o .ll3 Species richness. n 22.25 5.38 17.82 7.21 0.041 0.001 1 2.38 2.03 2.25 3.06 0.005 0.804 I Height-density-index. cm Height. cm Sand sagebrush Grass Forbs Slope. degrees 0.191 0.268 0.920 0.730 0.359 0.185 0.-966 0.156 0.732 0.063 0.421 �123 Table 33. Habitat at observed and available locations of greater prairie-chickens in northeastern Colorado during winter (1 Nov - 14 Feb) , 1986-88. Observed (36) Habitat variable Height-density-index, cm R SD Available (36) ~ f SD Lax .£ 9.63 6.46 13.52 8.56 0.100 0.033 Height, cm Sand sagebrush Grass Forbs 36.25 89.17 44.31 41.99 35.81 46.15 39.17 89.03 52.64 43.40 34.76 48.68 0.847 0.862 0.755 0.773 0.987 0.459 Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 67.36 5.14 27.50 2.22 2.22 0.00 25.69 2.36 5.42 2.78 10.00 1.39 21.46 9.06 20.96 4.99 4.99 21.97 8.02 22.46 10.24 10.24 0.891 0.473 0.685 0.000 0.000 18.37 6.92 12.09 8.57 12.31 3.71 70.28 5.00 24.31 2.92 2.92 0.00 21.67 1.81 4.44 2.08 9.86 1.53 19.49 7.09 7.15 4.53 14.37 4.44 0.727 0.887 0.003 0.000 0.364 0.288 0.571 0.945 0.535 0.716 0.716 1.000 0.370 0.737 0.680 0.669 0.965 0.886 Species richness, 11 6.00 5.40 5.97 4.94 0.600 0.982 Slope, degrees 1.89 1.67 3.08 9.84 0.000 0.477 �124 Table 34. Habitat at locations prairie-chickens in northeastern 1986-88. of radio-marked male and female greater Colorado during winter (1 Nov - 14 Feb), Males Habitat variable ~ Height-density-index, SD Females & (18) f SD Lax ~ 10.91 7.25 8.36 5.47 0.255 0.241 Height, cm Sand sagebrush Grass Forbs 38.61 88.89 40.83 46.58 42.06 46.03 33.89 89.44 47.78 38.06 29.50 47.35 0.413 0.154 0.908 0.741 0.964 0.658 Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 71.67 6.94 21. 39 1.11 1.11 0.00 20.56 1. 67 2.50 1.11 10.28 0.56 16.09 11.39 16.87 3.66 3.66 25.50 5.69 23.25 5.94 5.94 0.066 0.007 0.196 0.053 0.053 15.52 7.07 4.29 2.74 12.18 1.62 63.06 3.33 33.61 3.33 3.33 0.00 30.83 3.06 8.33 4.44 9.72 2.22 19.94 6.89 16.27 11.74 12.77 4.92 0.311 0.916 0.000 0.000 0.848 0.000 0.234 0.240 0.080 0.186 0.186 1.000 0.094 0.555 0.157 0.256 0.895 0.187 4.94 4.83 7.06 5.87 0.432 0.247 1. 39 1.46 2.39 1. 75 0.459 0.072 Species richness, Slope, degrees I! em (18) I I �125 Table 35. Habitat at locations of radio-marked greater prairie-chickens in northeastern Colorado during morning, afternoon, and evening periods during winter (1 Nov - 14 Feb) 1986-88. Differences (f < 0.05) between means for each habitat variable are indicated by different superscripts. Morning Habitat variable (12) Afternoon SD Height-density-index, cm 3.36 (12) SD 10.42a,b 6.06 41.25 36.69 50.07 25.83a 72. SOb 33.33a 41. 50 30.64 41. 03 32.76 10.94 3l. 65 76.25a 5.428 19.178 1.25a l. 25a 8.01 9.88 9.25 2.26 2.26 43.66 30.46 47.70 Cover, % Bare Sand sagebrush Grass Cool season grass Need1e-and-thread Sixweeks annual fescue Warm season grass Blue grama Sand dropseed Prairie sandreed Corn Forbs 69.588 3.338 26.678 0.42a o .42a 0.008 26.258 0.42a 5.00a 0.42a 12.08a,b 0.42a,b 10.10 6.15 11.93 l.44 l.44 5.088 4.58 6.45 1.008 l.21 l. 62 Species richness, Slope, degrees n 56.25a 6.6]8 36.67a 5.00a 5.008 0.008 32.92a 6.67a 10.42a.b 6.67a 3.33a 3.75a SD 12. SOb 34.58a 83.75a.b 42.50a 48.33a 111.25a 57.08a (12) 7.78 Height, cm Sand sagebrush Grass Forbs 11.89 l.44 6.03 l.44 13.39 l.44 Evening i.69 7.69 O.OOa 26.58 10.94 19.36 14.20 7.49 5.69 17.92a 10.10 O.OOa 0.83b l. 25a 14.58b 1.95 2.26 13 .05 O.OOb 4.17 2.258,b 1. 86 �.~ HABITAT TYPES N ~ ACHCU.1UE tSd NH.WA'OIIS • 1HOIrr_'" m m UOfIItQn'-UD 0IIA8I lIT] till] o o - - - o o 0MI8 1tICIII'-TAU. 0RASa IIN£JlIHtWT-TAU.~ foD.TAU. GRAIl ~TAU.OItASS CXUffY ROADS SCALE IN MLES 1 1 2 3 234 SCALE IN KLOMETERS Fig. 10. 1986-88. Distribution of 10 habitat types in greater prairie-chicken use areas in northeastern Colorado, I--' N (J\ �_-- ....-- N HABIT A T TYPES II TREESIRESDENTIAL AGRICU. TlIE ~ ~ • AJlNJAlIFOFB SHORT -M> (JtASS SAGElstK>RT -M) GRASS '·.iiii.iiil SHORT-TALL mASS I':::.H SAGE/SHORT-TALL k> I ~ r ::: I GRASS TALL GRASS SAGEJUD- TAU. GRASS - - - - COlHTY ROADS SCALE IN MILES 012 I I o 1 I I I 2 3 I SCALE N KLOMETERS Fig. 11. Distribution of 45 specific (delineated by number) and 10 general habitat quarter of a greater prairie-chicken study area in northeastern Colorado, 1986-88. types in the northwestern I-' N --..J �N HABITAT TYPES TREESIRESDENTIAL ~ AGRIClJ._TlIE ~ MNJALlFOfB SHORT -M) ~ss I~~:~!:H SAaElSOORT oM) GRASS SHORT-TAU. GRASS mm'=:j SAOEISHORT-TAU. MASS I))j til>- TAU. GRASS j: : : : I - - - - SAGEJt.4D- TALL GRASS COl.MY ROADS SCALENMLES 012 I o I 1 I I I 2 3 I SCALE IN KLOMETERS Pig. 12. Distribution of 45 specific (delineated by number) and 10 general hAhitat quarter of a greater prairie-cllicken study area in northeastern Colorado, 1986-88. ---~ types in the southwestern t-' tv oo �---.~ HABITAT TYPES N II TREESlFlESIemAL AGRIClL 1\R: ~ MNJAL.JFOfB ~ 1': : SHORT -M> GRASS •• n u n L.J r c· )jd - - - - SAOEISHORT-MD SHORT-TAll. GRASS GRASS SAGE/SHORT - TAll. GRASS MD- TAll. QRASS SAGEI~ TALL GRASS COlNTY ROADS SCALE IN MLES 012 I I o 1 I I I 2 3 I SCALE IN KLOMETERS Fig. 13. Distribution of 45 specific (delineated by number) and 10 general habitat quarter of a greater prairie-chicken study area in northeastern Colorado, 1986-88. types in the southeastern I-' N \0 �N HABIT AT TYPES II TREWRESOOffiAL ~ AGiiClLME ~ NNlAUFOfB • SHORT-Wl GRASS SAOEIstDU-MD SHORT-TMJ. aRASS 1:'::::':1 SAGE/SHOOT-TMJ. 1\/1 w}-TALLGRASS 1 - - - - o GRASS 11:1:11111:I'j I: :: I-' W GRASS SAGEItJO-TAll. GRASS COLmY ROADS SCALE t.J MLES 012 I I o 1 I I I 2 3 I SCALE IN KILOMETERS Fig. 14. Distribution of 45 specific (delineated by number) and 10 general habitat quarter of a greater prairie-chicken study area in northeastern Colorado, 1986-88. types in the northeastern �131 Table 36. Area (%) of different habitat types on a 301 km2 greater prairiechicken study area in northeastern Colorado. Categorya Habitat type Trees/residential 35 Trees/residential 0.98 0.98 Corn Wheat Alfalfa Millet Soybean Rye Sorghum Sudan 13.25 8.98 0.94 0.23 1.95 0.48 0.05 0.07 0.60 Annuals Hairy goldenaster 1.83 1.78 0.05 Agriculture 1 3 4 6 7 8 9 10 Annual/forb 5 29 Short-mid 2 11 34 37 grass Short-mid warm season grasses/annuals Smooth brome/orchardgrass Cool and short-mid warm season grasses/annuals Psoralea/short-mid warm season grasses/annuals Sage/short-mid grass 12 Sand sagebrush/cool and short-mid warm season grasses/annuals 13 Sand sagebrush/cool and short-mid warm season grasses 15 Sand sagebrush/cool and short-mid warm season grasses/muhly 16 Sand sagebrush/Yucca/cool and short-mid warm season grasses 30 Sand sagebrush/Psoralea/cool and short-mid warm season grasses 43 Yucca/cool and short-mid warm season grasses Short-tall 39 40 41 42 Area grass Cool and short-tall warm season grasses Psoralea/short-tall warm season grasses Short-tall warm season grasses Short-tall warm season grasses/muhly 4.58 2.67 0.76 1.06 0.10 26.36 9.87 7.23 6.14 0.37 2.61 0.15 2.80 1.62 0.17 0.84 0.16 Sage/short-tall grass 33.05 14 Sand sagebrush/cool and short-tall warm season grasses 5.74 18 Sand sagebrush/Psoralea/cool and short-tall warm season grasses/muhly 0.55 21 Sand sagebrush/short-tall warm season grasses 12.90 22 Sand sagebrush/short-tall warm season grasses/muhly 7.91 23 Sand sagebrush/Yucca/cool and short-tall warm season grasses/annuals 0.29 25 Sand sagebrush/Yucca/cool and short-tall warm season grasses/muhly 1.09 28 Sand sagebrush/Yucca/short-tall warm season grasses 0.73 31 Sand sagebrush/Yucca/short-tall warm season grasses/muhly 0.03 38 Sand sagebrush/cool and short-tall warm season grasses/muhly 3.77 44 Yucca/cool and short-tall warm season grasses 0.05 �132 Table 36. Continued. Categorya Mid-tall grass 19 20 33 36 Habitat type Mid-tall warm season grasses Mid-tall warm season grasses/muhly/annuals Cool and mid-tall warm season grasses/annuals Psoralea/mid-tall warm season grasses/muhly Sage/mid-tall grass 17 Sand sagebrush/mid-tall warm season grasses/annuals 24 Sand sagebrush/mid-tall warm season grasses 26 Sand sagebrush/Yucca/mid-tall warm season grasses 27 Sand sagebrush/Yucca/mid-tall warm season grasses/muhly 32 Yucca/mid-tall warm season grasses County roads 45 County roads Area 5.27 4.73 0.13 0.21 0.20 11.34 4.01 5.79 0.9l 0.55 0.08 0.53 0.53 aCeneral categories of habitat types are referenced on maps by both name and number. I �133 Table 37. Common plant species on a greater prairie-chicken study area in northeastern Colorado, 1986-88. Undisturbed Disturbed Agriculturea RangelanJ' Sandhill C Relatively flatd smooth brome Cheat grass brome Stinkgrass Orchardgrass \lheat Quackgrass Crested wheatgrass Bottlebrush squirreltail Foxtail barley Rye \Iild oat Sand dropseed Needle-and-thread Showy chloris lIindmillgrass False buffalograss \litchgrass panicum COlT1llOn barnyardgrass Yellow bristlegrass Green bristlegrass Foxtai l bristlegrass Mi llet Sorghum Sudan Mat sandbur Corn COlT1llOn Russianthistle Fireweed summercypress Lambsquarters goosefoot Sand amaranth Redroot amaranth Common purslane Prairie pepperweed Alfalfa \lhite clover Yellow sweetclover IIhite sweetclover Soybean COIT1llOn puncturevine Leafy spurge COlT1llOn mil kweed Sand mi lkweed Bush morningglory Bracted verbena Buffalobur nightshade Canada horseweed Prairie sunflower \lestern ragweed Bull thistle Smooth brome Cheatgrass brome Kentucky bluegrass Stinkgrass Purple lovegrass Blowout grass Quackgrass Crested wheatgrass IIild oat Sand dropseed Red threeawn lIindmillgrass False buffalograss lIitchgrass panicum Mat sandbur lIillow Chinese elm Veiny dock COIT1llOn Russianthistle Fireweed sUlll1lercypress Lambsquarters goosefoot Sand amaranth Sandverbena COIT1llOn purslane Intermediate pricklepoppy Roughseed clalTlllYweed Rocky Mountain beeplant Flixweed tansymustard Pinnate tansymustard Sl imflower scurfpea American vetch Lambert crazyweed Common puncturevine Texas croton Fendler euphorbia Scarlet globemallow Russian-olive Stemless cymopterus Sand milkweed Bush morningglory Bracted verbena American nightshade Buffalobur nightshade Buffalogourd Cheatgrass brome Sixweeks annual fescue Blowout grass Prairie junegrass Prairie sandreed Sandhill I1'lJhly Sand dropseed Indian ricegrass Needle-and-thread Red threeawn Blue grama Hairy grama Switchgrass panicum Sand bluestem Little bluestem Sand sedge Needle spikerush Prairie dayflower Prairie spiderwort Sma II soapweed Prairie onion Annual eriogonum Veiny dock Fireweed sl.lTlllercypress Narrow-leaved goosefoot Slender snakecotton Sandverbena Plains larkspur Silvery bladderpod Arkansas rose Bushpea IIhite prairieclover Silky prairieclover Purple prairieclover Lead plant Silverleaf scurfpea Lemon scurf pea American vetch Missouri milkvetch Fendler euphorbia Tenpetal mentzelia Brittle pricklypear COIT1llOn pricklypear Ballcactus Scarlet gaura Shrubby eveningprimrose Prairie eveningprimrose Stemless cymopterus Siberian dogbane Plains milkweed Sand mi lkweed Nuttall evolvulus Cheatgrass brome Sixweeks annual fescue Sand lovegrass Prairie sandreed Sandhill muhly Sand dropseed Needle-and· thread Red threeawn Blue grama Sideoats grama Sand paspalum Switchgrass panicum Big bluestem Sand bluestem Little bluestem Yellow Indiangrass Sand sedge Needle spikerush Prairie spiderwort Sma II soapweed Prairie onion Annual eriogonum Fireweed sUlll1lercypress Narrow-leaved goosefoot Prairie flameflower Plains larkspur Silvery bladderpod Arkansas rose Silky prairieclover Purple prairieclover Lead plant Lemon scurfpea Sl imflower scurfpea Lambert crazyweed Missouri milkvetch Groundplum milkvetch Texas croton Tenpetal mentzelia Brittle pricklypear COIT1llOn pricklypear Scarlet gaura Shrubby eveningprimrose Prairie eveningprimrose Stemless cymopterus Plains milkweed Nuttall evolvulus Hood phlox IIhite borage ClalTlllY groundcherry Narrow-leaved �134 Table 37. Continued. Undisturbed Disturbed Agriculturea Canada thistle Platte thistle Prickly lettuce Common dandelion a1ncluding blncluding c1ncluding dlncluding 44. habitats habitats habitats habitats Rangelandb Sandhi IIC Hairy goldenaster Canada horseweed Louisiana sagewort Prairie sunflower Western ragweed Platte thistle Prickly lettuce Rush skeletonplant Pink-throated morningglory Hood phlox Hairy puccoon White borage Clammy groundcherry Narrow-leaved penstemon Gilia penstemon Downy painted-cup Louisiana broomrape Woolly plantain Dotted gayfeather Missouri goldenrod Ironplant goldenweed Spreading fleabane Sand sagebrush Common sagewort Hooker palafoxia Nippleweed Prairie sunflower Western ragweed Relatively flatd penstemon Gil ia penstemon Woolly plantain Dotted gayfeather Blazing star Hairy goldenaster Missouri goldenrod Ironplant goldenweed Spreading fleabane Louisiana sagewort Sand sagebrush Old plainsman Prairie coneflower Nippleweed Prairie sunflower Western ragweed Common pearlyeverlasting Platte thistle Yellow salsify Wavyleaf microseris 1, 3, 4, 6, 7, 8, 9, 10, 11, and 45. 2, 5, 29, 34, 35, 37, and 45. 12, 13, 14, 15, 17, 18, 20, 21, 22, 24, 25, 26, 27, 28, 31, 32, 36, 38, and 39. 12, 13, 14, 16, 17, 18, 19, 21, 22, 23, 24, 26, 28, 30, 33, 38, 40, 41, 42, 43, and I I �135 Trees/residential: Chinese elm, Russian-olive, willow, and Kentucky bluegrass frequently occurred in this habitat type. Several additional species were common including needle-and-thread, sand dropseed, cheatgrass brome, sand lovegrass, sand sagebrush, blue grama, prairie sandreed, switchgrass panicum, and crested wheatgrass. These habitats were relatively moist, shady, and disturbed. Trees/residential (35): Same as above description. Agriculture: Agriculture was common throughout the study area, especially on relatively level sites conducive to center-pivot irrigation. Corn was the most common crop on irrigated land while millet was most common on non-irrigated land. Wheat, rye, sorghum, sudan, alfalfa, and soybeans were planted, but in smaller quantities. Other plants included witchgrass panicum, green bristlegrass, mat sandbur, redroot amaranth, and common dandelion. None of the crops provided nesting cover, but most provided grain, forage and/or cover in autumn and winter. Corn (1): Corn was commonly planted in circular fields with center-pivot irrigation in mid to late May and harvested in October. Fields were left unplowed throughout the winter and corn stubble and kernels were abundant. During the peak of the growing season (Jul), corn reached a height of 2.5 m and provided 95-100% canopy cover. The understory, particularly along the edges of fields, consisted'of witchgrass panicum, green bristlegrass, mat sandbur, redroot amaranth, and common dandelion. I I Wheat (3): Wheat was planted in center-pivot irrigated fields in August or September. It was frequently grazed during autumn and winter (0.1 m in height at the time) and harvested in June. Wheat reached a height of about 1 m during May and June (year following planting) , but generally provided only 75-85% canopy cover. Additional species included witchgrass panicum, green bristlegrass, mat sandbur, redroot amaranth, and common dandelion. Alfalfa (4): Alfalfa was planted in center-pivot irrigated fields, cut periodically, and was generally available all year. Alfalfa ranged in height from 0.1 to 0.8 m and provided 80-90% canopy cover. Additional species frequently include witchgrass panicum, green bristlegrass, mat sandbur, redroot amaranth, and common dandelion. Millet, was commonly planted as a cover crop with alfalfa to increase alfalfa seedling growth (usually planted in May). Millet (6): Millet was planted in non-irrigated fields in May and harvested in August or September. Stubble and waste millet were abundant throughout the winter. Millet reached a height of 0.5 m, but generally provided only 75-85% canopy cover. Additional species included witchgrass panicum, green bristlegrass, mat sandbur, redroot amaranth, and common dandelion. Alfalfa was often grown as an understory plant with millet in center-pivot irrigated fields (millet was not harvested in the latter case). Soybean (7): Center-pivot irrigated May and harvested in September. fields were planted with soybeans Virtually no stubble or waste in �136 remained throughout the winter. Soybeans reached a height of 1 m and provide 95-100% canopy cover. The understory, particularly on the edges of fields, consisted of witchgrass panicum, green bristlegrass, mat sandbur, redroot amaranth, common dandelion, and corn (planted in earlier rotations). Rye (8): Rye was planted in center-pivot irrigated fields in August or September. Rye was often grazed during autumn and winter (about 0.1 m in height at the time) and harvested in June (not always harvested). Rye reached a height of 1 m during May and June (year following planting), but generally provided only 80-90% canopy cover. Additional species included witchgrass panicum, green bristlegrass, mat sandbur, redroot amaranth, and common dandelion. Sorghum (9): Sorghum was planted (usually in non-irrigated fields) in May and harvested in August or September. Stubble and waste sorghum were abundant throughout the winter. Sorghum reached a height of 1 m, but generally provided only 75-85% canopy cover. The understory consisted of witchgrass panicum, green bristlegrass, mat sandbur, redroot amaranth, common dandelion, and millet (millet may be mixed with sorghum seeds). Sudan (10): Sudan, a hybridized version of sorghum and millet, was occasionally planted in center-pivot irrigated fi~lds. Sudan tolerated dry conditions and was commonly planted around the edges of irrigated crop fields. It was usually planted in May and grazed during late autumn or winter when the adjacent crop stubble was also grazed. Although stubble was abundant throughout the winter, waste sudan was readily eaten by cattle and generally not available for wildlife. Sudan reached a height of 2 m and provided about 85-95% canopy cover. The understory consisted of witchgrass panicum, green bristlegrass, mat sandbur, redroot amaranth, common dandelion, and millet (millet may be mixed with sudan seeds). Annual/forb: This habitat was dominated by annual and/or non-grass species; it was typical of disturbed sites on the study area. Most of this habitat was either around windmills or in fallow center-pivot irrigated fields. A variety of annual species dominated this type including cheatgrass brome, wheat, witchgrass panicum, green bristlegrass, millet, mat sandbur, common Russianthistle, lambsquarters goosefoot, sand amaranth, redroot amaranth, Rocky Mountain beeplant, pinnate tansymustard, Texas croton, bracted verbena, hairy goldenaster, prairie sunflower, and prickly lettuce. The variety of dominant plants was largely a response to variables such as moisture condition, disturbance, and previous vegetation. Annuals (5): Most of this habitat was in fallow center-pivot irrigated fields. Several species dominated including cheatgrass brome, wheat, witchgrass panicum, green bristlegrass, millet, mat sandbur, common Russianthistle, lambsquarters goosefoot, sand amaranth, redroot amaranth, Rocky Mountain beeplant, pinnate tansymustard, Texas croton, bracted verbena, prairie sunflower, and prickly lettuce. The variety of dominant plants was largely a response to variables including moisture, disturbance, and previous vegetation. For �137 example, in relatively moist and disturbed areas around windmills, bracted verbena (Jun-Jul), pinnate tansymustard (Jun), Rocky Mountain beeplant (Jul-Aug), cheatgrass brome (May), and lambsquarters goosefoot (Jul) dominated. Drier disturbed areas frequently had Texas croton and sand amaranth as dominant species. Hairy goldenaster (29): Hairy goldenaster was a perennial forb that dominated 1 relatively dry disturbed site on the study area. Few other species were present. Short-mid grass: This habitat was typical of disturbed and/or heavily overgrazed areas. The orchardgrass/smooth brome area was an exception, likely because it was specifically planted to be heavily grazed. Disturbance, such as previous agriculture, spraying, and/or fire, had eliminated sand sagebrush from this habitat. Sand lovegrass, sand dropseed, red threeawn, blue grama, and sand paspalum dominated (except in planted areas). Additional species included cheatgrass brome, needleand-thread, green brist1egrass, mat sandbur, common Russianthistle, lambsquarters goosefoot, redroot amaranth, Rocky Mountain beeplant, slimflower scurfpea, Texas croton, stemless cymopterus, bracted verbena, buffalobur nightshade, Louisiana sagewort, prairie sunflower, and western ragweed. This habitat provided essentially no cover for prairiechickens. " Short-mid warm season grasses/annuals (2): This habitat was typical of disturbed and/or heavily over-grazed areas. Sand lovegrass, sand dropseed, red threeawn, blue grama, and/or sand paspalum dominated. Rarely were all 5 species in the same location. Numerous species of annual grasses and forbs were common including cheatgrass brome, lambsquarters goosefoot, Rocky Mountain beeplant, Texas croton, stemless cymopterus, bracted verbena, Russian thistle, prairie sunflower, and western ragweed. Orchardgrass/smooth brome (11): This habitat occurred only in centerpivot irrigated fields. It was used entirely for May-October cattle grazing. Smooth brome and orchardgrass co-dominated and provided vegetation throughout the grazing season. The vegetation was typically less than 0.1 m in height. Additional common species included green bristlegrass, mat sandbur, redroot amaranth, and buffalobur nightshade. Cool and short-mid warm season grasses/annuals (34): This type was typical of disturbed and/or heavily over-grazed areas. It was dominated by sand lovegrass, quackgrass, sand dropseed, needle-andthread, red threeawn, blue grama, and/or sand paspalum. Rarely were all 5 species in the same location. In particular, quackgrass was localized. In addition to perennial grasses, numerous species of forbs and annual grasses were common including cheatgrass brome, common Russianthistle, Texas croton, prairie sunflower, and western ragweed. Psoralea/short-mid warm season grasses/annuals (37): Cheatgrass brome, blue grama, slimflower scurfpea, and Louisiana sagewort dominated this overgrazed habitat type. Additional species such as brittle �138 pricklypear, common pricklypear, and Platte thistle were also common. Although slimflower scurfpea grew to 1 m, it provided little cover. Grasses rarely reached a height of 0.1 m. Sage/short-mid grass: Needle-and-thread, blue grama, and sand sagebrush dominated this heavily overgrazed habitat type. Additional dominant species frequently included sand lovegrass, sandhill muhly, sand dropseed, hairy grama, sand paspalum, little bluestem, small soapweed, and slimflower scurfpea. Other common plants included sixweeks annual fescue, sand sedge, annual eriogonum, brittle pricklypear, common pricklypear, woolly plantain, prairie sunflower, western ragweed, and Platte thistle. This habitat provided little cover, except in the immediate vicinity of sand sagebrush or small soapweed. Sand sagebrush/cool and short-mid warm season grasses/annuals (12): Sand lovegrass, sand dropseed, needle-and-thread, blue grama, sand paspalum, and sand sagebrush dominated this habitat. Numerous other species were common, including sixweeks annual fescue, sand sedge, annual eriogonum, Texas croton, brittle pricklypear, common pricklypear, woolly plantain, prairie sunflower, western ragweed, and Platte thistle. This type provided little cover, since most of the perennial grasses had foliage that rarely reached a height of 0.1 m. , Sand sagebrush/cool and short-mid warm season grasses (13): This habitat type was dominated by quackgrass, needle-and-thread, blue grama, and sand sagebrush. Numerous other species were common, including sixweeks annual fescue, quackgrass, annual eriogonum, brittle pricklypear, common pricklypear, woolly plantain, and Platte thistle. Sand sagebrush/cool and short-mid warm season grasses/muhly (15): Sand sagebrush, sandhill muhly, sand dropseed, needle-and-thread, blue grama, hairy grama, sand paspalum, and little bluestem dominated this relatively steep habitat type. Hairy grama and sandhill muhly were most common on the steepest sites. Sixweeks annual fescue, sand sedge, annual eriogonum, brittle pricklypear, common pricklypear, woolly plantain, and western ragweed were also common. Sand sagebrush/Xucca/cool and short-mid warm season grasses (16): Sand dropseed, needle-and-thread, blue grama, small soapweed, and sand sagebrush dominated this habitat type. Additional species included sixweeks annual fescue, prairie sandreed, red threeawn, sand sedge, brittle pricklypear, common pricklypear, and woolly plantain. Sand sagebrush/Psoralea/cool and short-mid warm season grasses (30): Sand dropseed, needle-and-thread, blue grama, little bluestem, slimflower scurfpea, sand sagebrush, prairie sunflower, and western ragweed dominated in this type. Additional common species included sixweeks annual fescue, prairie sandreed, red threeawn, sand sedge, annual eriogonum, Rocky Mountain beeplant, brittle pricklypear, common pricklypear, and woolly plantain. Yucca/cool and short-mid warm season grasses (43): Sand dropseed, needle-and-thread, blue grama, and small soapweed dominated this limited habitat type. Additional species included sixweeks annual �139 fescue, pra~r~e sandreed, sand sedge, brittle pricklypear, pricklypear, and woolly plantain. common Short-tall grass: Much of this overgrazed habitat appeared to have undergone sagebrush removal, either through land use or spraying. Sand dropseed, blue grama, and little bluestem frequently dominated. Other dominant species included quackgrass, prairie sandreed, sandhill muhly, needleand-thread, hairy grama, switchgrass panicum, sand paspalum, sand bluestem, and slimflower scurfpea. Other common species included sand sedge, annual eriogonum, common pricklypear, woolly plantain, spreading fleabane, prairie sunflower, and western ragweed. Cool and short-tall warm season grasses (39): Sand lovegrass, quackgrass, prairie sandreed, sand dropseed, needle-and-thread, blue grama, hairy grama, sand paspalum, switchgrass panicum, sand bluestem, little bluestem, and/or hairy grama dominated. Because of the diversity of this habitat type, few of the species dominated in any given location, even though all were usually present. Common annuals included sixweeks annual fescue and western ragweed. Psoralea/short-tall warm season grasses (40): Blue grama, little bluestem, and slimflower scurfpea dominated on this restricted type. This habitat was relatively flat and less sandy than most sites. Other common species included sand sedge, prairie'spiderwort, annual eriogonum, common pricklypear, woolly plantain, spreading fleabane, and western ragweed. Short-tall warm season grasses (41): Prairie sandreed, needle-andthread, sand dropseed, blue grama, sand paspalum, switchgrass panicum, and/or little bluestem dominated. Common annuals included sixweeks annual fescue, prairie sunflower, and western ragweed. Short-tall warm season grasses/muhly (42): Prairie sandreed, muhly, sand dropseed, and blue grama dominated. sandhill Sage/short-tall grass: Prairie sandreed, sand dropseed, needle-and-thread, blue grama, little bluestem, and sand sagebrush (and/or small soapweed) dominated most of this habitat type. Additional common species included prairie sunflower and western ragweed on relatively flat areas and sandhill muhly, hairy grama, and lemon scurfpea on steep sites. This habitat provided cover for prairie-chickens, especially in the immediate vicinity of sand sagebrush plants. Most of this type appeared to be relatively undisturbed by past land management practices, other than moderate to heavy cattle grazing. Sand sagebrush/cool and short-tall warm season grasses (14): Prairie sandreed, sand dropseed, needle-and-thread, blue grama, little bluestem, and sand sagebrush dominated. Common annuals included cheatgrass brome, prairie sunflower, and western ragweed. Sand sagebrush/Psoralea/cool and short-tall warm season grasses/muhly (18): Prairie sandreed, sand dropseed, needle-and-thread, blue grama, little bluestem, slimflower scurfpea, and sand sagebrush dominated on relatively flat sites while prairie sandreed, sandhill �140 muhly, hairy grama, little bluestem, sagebrush dominated on steep sites. lemon scurfpea, and sand Sand sagebrush/short-tall warm season grasses (21): Sand lovegrass, prairie sandreed, sand dropseed, needle-and-thread, blue grama, little bluestem, switchgrass panicum, and sand sagebrush dominated. Common annuals included sixweeks annual fescue, prairie sunflower, and western ragweed. Sand sagebrush/short-tall warm season grasses/muhly (22): Prairie sandreed, sandhill muhly, sand dropseed, needle-and-thread, blue grama, little bluestem, and sand sagebrush dominated. Sand sagebrush/1ucca/cool and short-tall warm season grasses/annuals (23): Sand dropseed, needle-and-thread, blue grama, sand paspalum, little bluestem, small soapweed, and sand sagebrush dominated. Common annuals included cheatgrass brome and western ragweed. Sand sagebrush/Xucca/cool and short-tall warm season grasses/muhly (25): Prairie sandreed, sandhill muhly, sand dropseed, needle-and-thread, blue grama, hairy grama, little bluestem, small soapweed, and sand sagebrush dominated on these relatively steep sandy areas. Sand sagebrush/Xucca/short-tall warm season grasses (28): Prairie sandreed, sand dropseed, needle-and-thread, blue grama, little bluestem, small soapweed, and sand sagebrush dominated. This type is similar to # 44 except for the presence of sand sagebrush. Sand sagebrush/Xucca/short-tall warm season grasses/muhly (31): Prairie sandreed, sandhill muhly, sand dropseed, needle-and-thread, blue grama, hairy grama, little bluestem, hairy grama, small soapweed, and sand sagebrush dominated on these relatively steep sandy areas. Sand sagebrush/cool and short-tall warm season grasses/muhly (38): Prairie sandreed, sandhill muhly, sand dropseed, needle-and-thread, blue grama, hairy grama, little bluestem, and sand sagebrush dominated on these relatively steep sandy areas. Yucca/cool and short-tall warm season grasses (44): Prairie sandreed, sand dropseed, needle-and-thread, blue grama, little bluestem, and small soapweed dominated. Mid-tall grass: Prairie sandreed and sand bluestem typically dominated in most of this type. Additional dominant species were sand lovegrass, sandhill muhly, sand dropseed, needle-and-thread, blue grama, hairy grama, switchgrass panicum, big bluestem, sand bluestem, little bluestem, yellow Indiangrass, and lemon scurfpea. Many of these habitats appeared to had undergone sand sagebrush removal, either through general patterns of land use or spraying. Some areas had been seeded with a variety of tall grasses (such as big bluestem and yellow Indiangrass). Mid-tall warm season grasses (19): Sand lovegrass, prairie sandreed, sand dropseed, needle-and-thread, blue grama, sand paspalum, switchgrass panicum, big bluestem, sand bluestem, little bluestem, I �141 and yellow Indiangrass dominated this diverse habitat type. Common annuals included cheatgrass brome and prairie sunflower. This habitat was generally the result of seeding efforts and was usually on flat areas formerly used for agriculture and/or intensive grazing. Although quite variable with respect to grazing treatment, much of this habitat provided tall dense cover. Mid-tall warm season grasses/muhly/annuals (20): Sand lovegrass, pra~r~e sandreed, sandhill muhly, sand dropseed, needle-and-thread, blue grama, hairy grama, switchgrass panicum, sand bluestem, and little bluestem dominated on these relatively steep sandy sites. Common sagewort and western ragweed were also common. Cool and mid-tall warm season grasses/annuals (33): Prairie sandreed, sand dropseed, needle-and-thread, sand paspalum, and switchgrass panicum dominated. Cheatgrass brome and Texas croton were also common. Psoralea/mid-tall warm season grasses/muhly (36): Prairie sandreed, sandhill muhly, hairy grama, sand bluestem, and lemon scurfpea dominated on these steep sandy areas. Sage/mid-tall grass: Sand lovegrass, prairie sandreed, s~ndhill muhly, sand dropseed, needle-and-thread, blue grama, sand bluestem, and little bluestem dominated. Sandhill muhly, hairy grama, witchgrass panicum, and switchgrass panicum were also dominant, but were more restricted in distribution. Many of these sites had been seeded with a variety of tall grasses (such as big bluestem and yellow Indiangrass). Sand sagebrush/mid-tall warm season grasses/annuals (17): Sand lovegrass, prairie sandreed, sandhill muhly, sand dropseed, needleand-thread, blue grama, hairy grama, sand bluestem, and little bluestem dominated. Sandhill muhly and hairy grama were more typical on steep sandy areas while sand lovegrass was common on flat areas. Cheatgrass brome, gilia penstemon, and western ragweed were common throughout. Sand sagebrush/mid-tall warm season grasses \(24): Cheatgrass brome, sand lovegrass, prairie sandreed, sand dropseed, needle-and-thread, blue grama, switchgrass panicum, big bluestem, sand bluestem, little bluestem, yellow Indiangrass, sand sagebrush, prairie sunflower, and western ragweed dominated. The diversity of species was partly a result of seeding of big bluestem, yellow Indiangrass, and other species. Other common species included cheatgrass brome, prairie sunflower, and western ragweed. Sand sagebrush/Yucca/mid-tall warm season grasses (26): Sand lovegrass, prairie sandreed, sand dropseed, needle-and-thread, blue grama, switchgrass panicum, sand bluestem, little bluestem, small soapweed, and sand sagebrush dominated. Sand sagebrush/Yucca/mid-tall warm season grasses/muhly (27): Sand lovegrass, prairie sandreed, sandhill muhly, sand dropseed, needleand-thread, hairy grama, switchgrass panicum, sand bluestem, little �142 bluestem, small soapweed, and sand sagebrush dominated this steep habitat type. Prairie sunflower was also a common species. Yucca/mid-tall warm season grasses (32): Prairie sandreed, sand dropseed, needle-and-thread, blue grama, switchgrass panicum, sand bluestem, little bluestem, and small soapweed dominated on this steep habitat type. County roads: Most county roads on the study area were slightly elevated (1-2 m), gravel, and approximately 10 m wide. Each road had a 5-m wide bank on either side generally bounded by a fence. Since most roads and banks were not affected by grazing pressure, they had numerous dense species of mid and tall grass species, such as prairie sandreed, sand dropseed, needle-and-thread, switchgrass panicum, green bristlegrass, big bluestem, sand bluestem, little bluestem, and yellow Indiangrass. Other common species included sandhill muhly, blue grama, sand sedge, small soapweed, annual eriogonum, common pricklypear, tenpetal mentzelia, Nuttall evolvulus, spreading fleabane, sand sagebrush, common sagewort, and prairie sunflower. County roads Female Preference (45): Same as above description. Hypothesis Distance between nest locations and both the nearest lek and the lek where each female was first observed was determined for 1986-88 (Fig. 15). Eightynine females had a mean distance of 3.67 km to the 1ek where first observed and 1.02 km to the nearest lek (Table 38). Nest-first 1ek distances ranged between 0.23-29.40 km (Fig. 16) and nest-nearest 1ek distances ranged between 0.23-2.39 km (Fig. 17). There was no difference in movement attributable to year (f> 0.10). However, yearling females moved further between the lek where first observed and their nest site than adults (~- 2.414, f = 0.019); the difference may be partially attributable to yearling dispersal. For instance,S of 6 females that nested more than 10 km from the lek where first observed or captured were yearlings. When 'disturbed' females (captured during the breeding season) were compared with 'undisturbed' females (captured prior to the breeding season), disturbed females moved further (~- 2.105, f 0.039) between the first visited lek and their nest site. As with yearling movements, movement by undisturbed females may be caused by migration/dispersal. Since undisturbed females were caught prior to the breeding season, some may have been caught prior to normal movements between seasonal home ranges. There was no difference (f > 0.05) for nest-nearest lek distance attributable to either age or disturbance status. Seventy-three percent (n = 90) of the females nested closer to a lek that was different from the lek on which they were first observed or captured. There was no difference (f > 0.10) associated with year. If Bradbury's (1981) prediction that most females (presumably more than 50%) should visit only 1 lek is true, then most females should have nested closer to the lek on which they were first observed. However, when compared with a predicted value of 50%, the observed value of 73% was higher (X2 - 10.364, f < 0.01). Disturbed females, 74.3% (n = 74), did not differ (X2 - 0.209, f> 0.10) from undisturbed females, 68.8% (n = 16). If disturbance was a factor, disturbed females should be expected to avoid leks where captured. �143 1986 o o o N o LEKS * NESTS o o o o oo 0 1987 o 1988 o ~o o 2 4km Fig. 15. Distribution of female greater prairie-chicken nests in relation to the lek where each female was first observed or captured during spring in northeastern Colorado, 1986-88. �144 Table 38. Distances (m) between each greater prairie-chicken nest, nearest lek, and the lek where each female was first observed and/or captured in northeastern Colorado, 1986-88. Lek visited Category first R Lek nearest to nest 11 Median R 2112.2 4327.9 6922.9 21 30 31 843.0 963.0 1139.0 962.1 999.8 1075.2 527.6 574.0 465.8 2348.4 4847.6 2248.8 6685.8 38 43 966.5 980.0 984.8 1021. 1 506.1 509.1 2211.4 3940.1 1874.9 5599.4 15 67 1166.0 849.0 1231. 2 971.1 577 .4 497.1 1018.7 518.0 11 Median Year 1986 1987 1988 22 31 36 2092.5 1768.0 1855.0 2855.8 3006.4 4734.5 Agea Adult Yearling 42 47 1690.5 2041.0 14 75 1767.0 1980.0 SO SD St.at.us" Undisturbed Disturbed " Totals 89 1874.0 3668.2 5224.6 82 975.0 aOne female of unknown-age was excluded from the sample for nearest lek nest distances. bFemales captured prior to the period of lek visitation were considered undisturbed and those captured on leks during the period of lek visitation were considered disturbed. Although direct examinations of home range size are difficult, if not interpretable (Beehler and Foster 1988), home range sizes were estimated to give an additional indication of the relevancy of Bradbury's (1981) prediction of home range size and lek distribution. Female home range size was estimated for both the early spring (prior to most lek visitation) and late spring (during lek visitation and nest establishment) (Table 39). By using a 75% probability contour, a conservative estimate of home range size was obtained. There were no differences (£ > 0.05) in home range size associated with sex, age, or disturbance status. However, home range size during late spring (R 624 ha) was larger (~ - 2.098, £ - 0.038) than in early spring (R - 213 ha) (Table 39). Since Bradbury (1981) predicted that females should have a diameter of their respective home ranges that was less than the distance between neighboring leks, home range diameter was calculated by considering the home range as a perfect circle (conservative estimate of diameter). The diameter of an average home range was 1.65 km (1.43 km using the median home range) for early spring and 2.82 km (1.84 km using the med~an home range) for late spring. �145 18 15 en w ..J < :E w u.. 12 9 a 3 o o 5 10 15 20 25 30 DISTANCE (KM) Fig. 16. Distribution of distances between 89 female greater prairie-chicken nest sites and leks where each female was first observed or captured in northeastern Colorado, 1986-88. �146 10 8 CI) W 6 --I < ~ w LL 4 2 o 0.0 0.4 0.8 1.2 1.6 2.0 2.4 DISTANCE (KM) Fig. 17. Distribution of distances between 82 female greater prairie-chicken nest sites and the nearest lek in northeastern Colorado, 1986-88. �147 Table 39. Home range size (ha, area within 75% probability contours generated with harmonic means on a grid size of 25 X 25) for female greater prairie-chickens in northeastern Colorado, 1986-88. Late spring Early spring n Median 2£ 3 2 25 165.0 328.7 156.8 149.3 328.7 210.9 Age Adult Yearling 22 8 165.0 134.9 Statusa Undisturbed Disturbed 27 3 Totals 30 Category SD n Median 2£ SD U5.6 247.9 252.7 21 35 39 252.5 262.9 312.1 526.9 349.9 938.4 749.8 292.0 2896.2 175.9 313.6 97.2 439.2 48 47 264.5 276.2 367.3 307.6 899.6 2671.9 156.8 165.0 219.6 149.3 249.6 U5.6 18 77 470.1 2~.8.0 649.0 626.3 981.0 2062.2 160.8 212.6 239.3 95 266.0 630.6 1900.7 Year 1986 1987 1988 aFemales captured prior to the period of lek visitation were considered undisturbed and those captured on leks during the period of lek visitation were considered disturbed. These estimates are greater than distances between neighboring leks (mean range of 1.18-1.31, median range of 1.15-1.42). Bradbury (1981) also suggested that detection distance (distance at which males can be readily detected by females) could be added to the diameters of female home ranges. If this procedure was used, females would have much larger home ranges than predicted. seventy-nine radio-marked females were observed on leks at least twice during the breeding season; 74.7% of these were observed on more than 1 lek (Fig. 18). When compared with the hypothesized upper limit of 50% (Bradbury 1981), the observed value was greater (X2 - 10.251, ~ < 0.01). If females visited leks several times during the breeding season as indicated, the number of females visiting more than 1 lek could have been higher than 85% (Fig. 18). As the number of visits to leks increased, the number of visits to different leks also increased (Fig. 19). One female was observed on 6 different leks in 8 lek visits. Another female was observed visiting the same lek on 9 consecutive observations. Undisturbed females (n = 17, 70.6%) did not differ (X2 = 0.192, ~ > 0.10) from disturbed females (n = 62, 75.8%) in their likelihood to visit more than 1 lek. If disturbance was a factor, disturbed females should have visited more leks than undisturbed females. A possible disturbance factor was examined by �---(f. -- n=15 ~ 6----- ----------------- 100 w ...J .•.... o TOTAL z 6 UNDISTURBED -c J: •••• o 95 , " 0: ::E C) n=34 90 z n=79 6.. - ,, o ~=56 CI) CI) W n=22,/ ,A · " O. .---- ..- .... --.-.--~ ... •••• > , ,, DISTURBED W o n=6 .- ... _- .._- 85 /\,-,' ~ ...J D. ·· -c ::E w 80 o z o 75 u.. u.. Ii: o 0.. o 0: 0.. 70 r 2 -- ---r-----r-----r-----~------. 3 4 5 6 7 MINIMUM NUMBER OF LEK VISITS Fig. 18. Proportion of female greater prairie-chickens visiting more than 1 lek in relation of times observed on a lek during spring in nortlleastern Colorado, 1986-88. to number I-.j> oo �o 7 TOTAL 6. UNDISTURBED o o 6 DISTURBED W I- en :> 5 MAXIMUM NUMBER OF DIFFERE.., ~ ~ LEK VISITS POSSIBLE 4 I- Z ~ 3 W LL LL n=25 ················~~=22 (5 2 n=79 0=56 ·.D=34 1 I 1 2 3 4 5 >5 LEKVISIT t-' p\0 Fig. 19. Number of different leks visited by female greater prairie-chickens times observed on leks in spring in northeastern Colorado, 1986-88. in relation to number of �150 compiling data on consecutive lek visits (Fig. 20). If disturbed females were adversely affected by being captured, they should have avoided the capture lek on their next lek visit. However, there was no difference between disturbed and undisturbed females after their first lek visit. The likelihood of visiting a different lek declined with later visits to leks. The probability of visiting a different lek in visits 3 - > 5 (n - 137 combined, 55.5%), declined (X2 - 7.889, f < 0.01) from the 2nd lek visit (n - 79, 74.7%). The trend to visit the same lek(s) in later visits may represent selection of leks by females, as opposed to effects of disturbance. DISCUSSION Reproductive success increased from 1986 to 1987 and then stabilized. These trends were reflected in the increase in both lek density and male attendance at leks in 1987 and 1988. Despite these trends, the lack of quantified density measurements, makes detailed interpretations of these results tenuous. Research has begun to show the importance of lightly grazed rangelands for providing critical nesting, roosting, and foraging habitat. Mapping of the study area may help design a management strategy that will help insure the long-term security of greater prairie-chickens in northeastern Colorado . Female Preference Hypothesis . ' Most females (73%) nested closer to a lek other than that where captured or first observed and most (79%) visited more than 1 lek during the breeding season. Measures of both home range size and lek visitation suggested these results were conservative. -These results contradict Bradbury's (1981) predictions that females should generally visit only 1 lek and have home ranges that include only 1 lek. Therefore, the 'female preference' hypothesis is rejected for greater prairie-chickens in northeastern Colorado. The most important aspect of Bradbury's (1981) theory is the relationship between female home range size and tendencies for males to form leks. However, even in Bradbury's (1981) paper on lek evolution, female home range size was interpreted as a correlative factor, with little justification given for possible causation. Considerations of home range size are often disregarded because of problems associated with measuring home ranges (Beehler and Foster 1988). However, sizes and distributions of home ranges are probably the most important considerations because they provide insight into why some species may form leks and others may not. Other hypotheses, 'least costly male' (Wrangham 1980), 'hotspot' (Bradbury and Gibson 1983), and 'hotshot' (Beehler and Foster 1988), have incorporated the idea of female home range size (sometimes substituted with female choice) into their respective theories explaining the evolution of lek behavior. However, none differ with respect to the expected positive correlation between ability of females to choose males and/or leks and tendency of males to form leks (Schroeder, in prep.). While Bradbury (1981) suggested that female preference could result in a predicted distribution of leks and female home ranges, his proposed predictions did not provide an adequate test for the idea that increasing home ranges lead to increasing concentrations of males. Bradbury's (1981) original explanation for disappearance of unselected leks (resulting in �I- Z W a: w LL LL 0 -'#. en - 0 w ~ 0 t: 80 w 70 en > > w ~ _J ~ w _J w ~60 I- > w I ~ I- wOO I TOTAL D UNDISTURBED D DISTURBED A , 0=79 , .,~ 0 a: o n=56 /\ , , .. ' -,_ ;' 0J.- .' '. n=25 , , " 0.. 0=34 ···········0··········· , ... ,: , o . I j::: I:J Z m « I « m 0=22 , , ,, 1-40 ~ 0 a: 0.. 2 3 4 5 >5 LEK VISIT ,_. ,_. lJ1 Fig. 20. Likelihood of a female greater prairie-chicken visiting a lek different than the previous relation to the consecutive number of lek visit in spring in northeastern Colorado, 1986-88. lek in �152 the predicted lek distribution) may have been too simplistic as it did little to interpret the effects of male-male competition and variable male breeding potential (ideas subsequently incorporated into the hotspot hypothesis (Bradbury and Gibson 1983)). Female movement also may have implications for greater prairie-chicken management. Land use practices in areas critical to lekking species may be modified to conform to specifications relating to lek locations. One way to do this would be to delineate an arbitrary circumference of habitat around all known leks. These areas may be considered the most critical for nesting habitat, a factor considered when mitigating for habitat disturbance or loss. However, little information is available describing female movements and nest sites in relation to lek location. This problem may be of particular importance for greater prairie-chickens in northeastern Colorado. The reestablishment of greater prairie-chickens in formerly occupied range may necessitate additional information on the relative importance and proximity of nest and lek habitat. LITERATURE CITED Ammann, G. A. 1944. Determining the age of pinnated grouses. J. Wildl. Manage. 8:170-171. Amstrup, S. C. 44:214-217. 1980. A radio-collar Beehler, B. M., and M. S. Foster. preference in the organization 131:203-219. for game birds. and sharp-tailed J. Wildl. Manage. 1988. Hotshots, hotspots, and female of lek mating systems. Am. Nat. Bradbury, J. W. 1981. The evolution of leks. Pages 138-169 in R. D. Alexander and D. W. Tinkle, eds., Natural selection and social behavior: recent research and new theory. Chiron Press, New York, N.Y. _____ , and R. M. Gibson. 1983. Leks and mate choice. Pages 109-138 Cambridge Univ. Press, Cambridge, P. Bateson, ed., Mate choice. Mass. Dixon, K. R., and J. A. Chapman. 1980. Harmonic mean measure activity areas. Ecology 61:1040-1044. Harrington, H. D. 1964. Manual of the plants of Colorado. Swallow Press Inc., Chicago, Ill. in of animal 2nd ed. The Miller, G. C. 1984. Development of a preservation program for insular populations of prairie grouse. Colorado Div. Wildl. Fed. Aid Rep. N-l-R. Jan. Pp. 129-170. Robel, R. J., J. N. Briggs, A. D. Dayton, and L. C. Hulbert. 1970g. Relationships between visual obstruction measurements and weight of grassland vegetation. J. Range Manage. 23:295-297. �153 ______ , J. J. Cebula, N. J. Silvy, C. E. Viers, and P. G. Watt. 1970g. Kansas. Greater prairie chicken ranges, movements, J. Wildl. Manage. 34:286-306. and habitat usage in Scott, T. G., and C. H. Wasser. 1980. Checklist of North American plants for wildlife biologists. The Wildl. Soc., Washington, D.C. Wrangham, R. W. 1980. Female choice of least costly males; a possible factor in the evolution of leks. Z. Tierpsychol. 54:357-367. r Prepared by __;_VL;L)~' ....•••••.•...:...........o~'-'-',.....__",.£""""""'L=.o.o:>iA~"'-- __ Michael A. Schroeder Graduate Research Assistant Approved by Clait E. Braun Wildlife Research Leader ��155 Appendix A. Colorado. Plants on a greater prairie-chicken Scientific r name Solanum americanum Vicia americana Eriogonum annuum Rosa arkansana Salvia azurea Mamillaria vivipara Andropogon gerardi Liatris sguarrosa Redfieldia flexuosa Bouteloua gracilis Verbena hastata Cryptantha minima Sitanion hystrix Verbena bracteata Opuntia fragilis Solanum rostratum Cirsium vulgare Ipomoea leptophylla Hoffmanseggia jamsii Solidago canadensis Conyza canadensis Cirsium arvense Mollugo verticillata Nepeta cataria Bromus tectorum Ulmus parvifolia Physalis heterophylla Echinochloa crusgalli Taraxacum officinale Oenothera strigosa Asclepias speciosa Anaphalis margaritacea Opuntia humifusa Tribulus terrestris Portulaca oleracea Salsola kali Artemisia campestris Helianthus annuus Aster tanacetifolius Agropyron desertorum Polygonum lapathifolium Rumex crispus Grindelia sguarrosa Oenothera coronopifolia Liatris punctata Chrysothamnus viscidiflorus Castilleja sessiliflora study area in northeastern Common name American nightshade American vetch Annual eriogonum Arkansas rose Azure sage Ballcactus Big bluestem Blazing star Blowout grass Blue grama Blue verbena Borage Bottlebrush squirreltail Bracted verbena Brittle pricklypear Buffalobur nigh~shade Bull thistle Bush morningglory Bushpea Canada goldenrod Canada horseweed Canada thistle Carpetweed Catnip Cheatgrass brome Chinese elm Clammy groundcherry Common barnyardgrass Common dandelion Common eveningprimrose Common milkweed Common pearlyeverlasting Common pricklypear Common puncturevine Common purslane Common Russianthistle Common sagewort Common sunflower Common tansy-aster Crested wheatgrass Curl top ladysthumb Curly dock Curlycup gumweed Cut-leaf eveningprimrose Dotted gay-feather Douglas rabbitbrush Downy painted-cup �156 Appendix A. Continued. Scientific name Munroa sguarrosa Euphorbia fendleri Senecio fendleri Antennaria neglecta Kochia scoparia Descurainia sophia Mirabilis linearis Hordeum jubatum Setaria italica Solidago gigantea Penstemon ambiguus Dalea ~ Setaria viridis Astragalus crassicarpus Chrysopsis villosa Bouteloua hirsuta Lithospermum caroliniense Apocynum cannabinum Phlox hoodii Oryzopsis hymenoides Argemone intermedia Haplopappus spinulosus Cristatella jamesii Poa pratensis Oxytropis lambertii Chenopodium album Amorpha canescens Euphorbia esula Psoralea lanceolata Andropogon scoparius Orobanche ludoviciana Artemisia ludiviciana Cenchrus pauciflorus Solidago missouriensis Astragalus missouriensis Sparganium eurycarpum Chenopodium pratericola Penstemon angustifolius Stipa comata Eleocharis acicularis Thelesperma megapotamicum Evolvulus nuttallianus Hymenopappus tenuifolius Dactylis glomerata Palafoxia sphacelata Rumex altissimus Ipomoea longifolia Descurainia pinnata Common name False buffalo grass Fendler euphorbia Fendler groundsel Field pussy toes Fireweed summercypress Flixweed tansymustard Four-o'clock Foxtail barley Foxtail bristlegrass Giant goldenrod Gilia penstemon Golden dalea Green bristlegrass Groundplum milkvetch Hairy goldenaster Hairy grama Hairy puccoon ~ Hemp dogbane Hood phlox Indian ricegrass Intermediate pricklypoppy Ironplant goldenweed James cristatella Kentucky bluegrass Lambert crazyweed Lambsquarters goosefoot Lead plant Leafy spurge Lemon scurfpea Little bluestem Louisiana broomrape Louisiana sagewort Mat sandbur Missouri goldenrod Missouri milkvetch Narrow-leaved bur-reed Narrow-leaved goosefoot Narrow-leaved penstemon Needle-and-thread Needle spikerush Nippleweed Nuttall evolvulus Old plainsman Orchardgrass Hooker palafoxia Pale dock Pink-throated morningglory Pinnate tansymustard �157 Appendix A. Continued. Scientific name Delphinium virescens Asclepias pumila Cirsium plattense Ratibida columnifera Commelina crispa Oenothera albicaulis Talinum parviflorum Koeleria cristata Allium textile Lepidium densiflorum Calamovilfa longifolia Tradescantia occidentalis Helianthus petiolaris Lactuca scariola Polygonum aviculare Eragrostis spectabilis Petalostemon purpureum Agropyron rep ens Aristida longiseta Amaranthus retroflexus Cleome serrulata Tridens elongatus Polanisia trachysperma Chrysothamnus nauseosus Lygodesmia juncea Elaeagnus angustifolia Tragopogon pratensis Amaranthus torreyi Andropogon hallii Sporobolus cryptandrus Eragrostis trichodes Asclepias arenaria Paspalum stramineum Artemisia filifolia Psoralea digitata Carex gravida Muhlenbergia pungens Abronia fragrans Gaura coccinea Sphaeralcea coccinea Chloris virgata Oenothera serrulata Apocynum sibericum Bouteloua curtipendula Petalostemon villosus Psoralea argophylla Lesguerella ludoviciana Festuca octoflora Common name Plains larkspur Plains milkweed Platte thistle Prairie coneflower Prairie dayflower Prairie eveningprimrose Prairie flameflower Prairie junegrass Prairie onion Prairie pepperweed Prairie sandreed Prairie spiderwort Prairie sunflower Prickly lettuce Prostate knotweed Purple lovegrass Purple prairieclover Quackgrass " Red threeawn Redroot amaranth Rocky Mountain beeplant Rough tridens Roughseed clammyweed Rubber rabbitbrush Rush skeletonplant Russian-olive Salsify Sand amaranth Sand bluestem Sand dropseed Sand lovegrass Sand milkweed Sand paspalum Sand sagebrush Sand scurfpea Sand sedge Sandhill muhly Sandverbena Scarlet gaura Scarlet globemallow Showy chloris Shrubby eveningprimrose Siberian dogbane Sideoats grama Silky prairieclover Silverleaf scurfpea Silvery bladderpod Sixweeks annual fescue �158 Appendix A. Continued. Scientific name Froelichia gracilis Psoralea tenuiflora Gaura parviflora Yucca glauca Bromus inermis Helenium autumnale Euphorbia marginata Erigeron divergens Cymopterus acaulis Eragrostis cilianensis Asclepias incarnata Panicum virgatum Mentzelia decapetala Croton texensis Psoralea linearifolia Senecio longilobus Euphorbia serpyllifolia Euphorbia dentata Cycloloma atriplicifolium Amaranthus graecizans Rumex venosus Nothocalais cuspidata Ambrosia coronopifolia Cryptantha jamesii Trifolium repens Penstemon albidus Petalostemon compactus Melilotus alba Cucurbita foetidissima Avena fatua Salix sp. Chloris verticillata Panicum capillare Plantago patagonica Setaria lutescens Sorghastrum nutans Tragopogon dub ius Melilotus officinalis Common name Slender snakecotton Slimflower scurfpea Small-flowered gaura Small soapweed Smooth brome Sneezeweed Snow-on-the-mountain euphorbia Spreading fleabane Stemless cymopterus Stinkgrass Swamp milkweed Switchgrass panicum Tenpetal mentzelia Texas croton Thread-leaved alfalfa Threadleaf groundsel Thyme-leaved eURhorbia Toothed euphorbia Tumble ringwing Tumbleweed amaranth Veiny dock Wavy leaf microseris Western ragweed White borage White clover White penstemon White prairieclover White sweetclover Buffalogourd Wild oat Willow Windmillgrass Witchgrass panicum Woolly plantain Yellow bristlegrass Yellow indiangrass Yellow salsify Yellow sweetclover �159 Appendix B. Phylogenetic list of scientific and common names for plants (Class Angiospermae) on a greater prairie-chicken study area in northeastern Colorado. Subclass Family Tribe Scientific name Common Monocotyledoneae Sparganiaceae Sparganium eurycarpum Gramineae Festuceae Bromus inermis Bromus tectorum Festuca octoflora Poa pratensis Eragrostis cilianensis Eragrostis spectabilis Eragrostis trichodes Redfieldia flexuosa Dactylis glomerata Tridens elongatus Hordeae Agropyron rep ens Agropyron desertorum Sitanion hystrix Hordeum j uba tum Aveneae Koeleria cristata Avena fatua Agrostideae Calamovilfa longifolia Muhlenbergia pungens Sporobolus cryptandrus Oryzopsis hymenoides Stipa comata Aristida longiseta Chlorideae Chloris virgata Chloris verticillata Bouteloua gracilis Bouteloua curtipendula Bouteloua hirsuta Munroa sguarrosa Paniceae Paspalum stramineum Panicum capillare Panicum virgatum Echinochloa crusgalli Setaria lutescens Narrow-leaved bur-reed Smooth brome Cheatgrass brome Sixweeks annual fescue Kentucky bluegrass Stinkgrass Purple lovegrass Sand lovegrass Blowout grass Orchardgrass Rough tridens Quackgrass Crested wheatgrass Bottlebrush squirrel tail Foxtail barley Prairie junegrass W'ild oat Prairie sandreed Sandhill muhly Sand dropseed Indian ricegrass Needle-and-thread Red threeawn Showy chloris W'indmillgrass Blue grama Sideoats grama Hairy grama False buffalograss Sand paspalum W'itchgrass panicum Switchgrass panicum Common barnyardgrass Yellow bristlegrass �160 Appendix B. Continued. Subclass Family Tribe Scientific name Setaria viridis Setaria italica Cenchrus pauciflorus Andropogoneae Andropogon gerardi Andropogon hallii Andropogon scoparius Sorghastrum nutans Cyperaceae Carex gravida Eleocharis acicularis Commelinaceae Commelina crispa Tradescantia occidental is Liliaceae Yucca glauca Allium textile Dicotyledoneae Salicaceae Salix sp. Ulmaceae Ulmus parvifolia Polygonaceae Eriogonum annuum Polygonum lapathifolium Polygonum aviculare Rumex venosus Rumex crispus Rumex altissimus Chenopodiaceae Cycloloma atriplicifolium Salsola kali Kochia scoparia Chenopodium pratericola Chenopodium album Amaranthaceae Amaranthus graecizans Amaranthus torreyi Amaranthus retroflexus Froelichia gracilis Nyctaginaceae Abronia fragrans Mirabilis linearis Aizoaceae Mollugo verticillata Common Green bristlegrass Foxtail bristlegrass Mat sandbur Big bluestem Sand bluestem Little bluestem Yellow indiangrass Sand sedge Needle spikerush Prairie dayflower Prairie spi.derwo r t; Small soapweed Prairie onion Willow Chinese elm Annual eriogonum Curl top ladysthumb Prostate knotweed Veiny dock Curly dock Pale dock Tumble ringwing Common Russianthistle Fireweed summercypress Narrow-leaved goosefoot Lambsquarters goosefoot Tumbleweed amaranth Sand amaranth Redroot amaranth Slender snakecotton Sandverbena Four-o'clock Carpetweed �161 Appendix B. Continued. Subclass Family Tribe Scientific name Common Portulacaceae Portulaca oleracea Talinum parviflorum Common purslane Prairie flame flower Delphinium Plains larkspur Ranunculaceae virescens Papaveraceae Argemone intermedia Intermediate pricklepoppy Capparidaceae f Cristatella jamesii Polanisia trachysperma Cleome serrulata James cristatella Roughseed clammyweed Rocky Mountain beeplant Lepidium densiflorum Lesguerella ludoviciana Descurainia sophia Descurainia pinnata Prairie pepperweed Silvery b l.adde rpod Flixweed tansymustard Pinnate tansymustard Rosa arkansana Arkansas Hoffmanseggia jamsii Petalostemon compactus Petalostemon villosus Petalostemon purpureum Amorpha canescens Psoralea argophylla Psoralea digitata Psoralea linearifolia Psoralea lanceolata Psoralea tenuiflora Dalea ~ Vicia americana Trifolium repens Melilotus officinalis Melilotus alba Oxytropis lambertii Astragalus missouriensis Astragalus crassicarpus Bushpea White prairieclover Silky prairieclover Purple prairieclover. Lead plant Silverleaf scurfpea Sand scurfpea Thread-leaved alfalfa Lemon scurfpea Slimflower scurfpea Golden dalea American vetch White clover Yellow sweetclover White sweetclover Lambert crazyweed Missouri milkvetch Groundplum milkvetch Tribulus Common puncturevine Cruciferae Rosaceae rose Leguminosae Zygophyllaceae terrestris Euphorbiaceae Croton texensis Euphorbia esula Euphorbia fendleri Euphorbia marginata Euphorbia serpyllifolia Texas croton Leafy spurge Fendler euphorbia Snow-on-the-mountain euphorbia Thyme-leaved euphorbia �162 Appendix B. Continued. Subclass Family Tribe Scientific name Common Euphorbia dentata Toothed euphorbia Malvaceae Sphaeralcea coccinea Scarlet globemallow Loasaceae Mentzelia decapetala Tenpetal mentzelia Cactaceae Opuntia fragilis Opuntia humifusa Mamillaria vivipara Brittle pricklypear Common pricklypear Ballcactus Elaeagnus Russian-olive Elaeagnaceae angustifolia Onagraceae Gaura coccinea Gaura parviflora Oenothera coronopifolia Oenothera serrulata Oenothera strigosa Oenothera albicaulis Scarlet gaura Small-flowered gaura Cutleaf eveningprimrose Shrubby eveningprimrose Common eveningprimrose Prairie eveningprimrose Cymopterus Stemless Umbelliferae acaulis cymopterus Apocynaceae Apocynum Apocynum sibericum cannabinum Siberian dogbane Hemp dogbane Asclepiadaceae Asclepias Asclepias Asclepias Asclepias speciosa pumila arenaria incarnata Common milkweed Plains milkweed Sand milkweed Swamp milkweed Convolvulaceae Evolvulus nuttallianus Ipomoea longifolia Ipomoea leptophylla Nuttall evolvulus Pink-throated morningglory Bush morningglory Phlox hoodii Hood phlox Lithospermum caroliniense Cryptantha m1n1ma Cryptantha jamesii Hairy puccoon Borage White borage Verbena Verbena Blue verbena Bracted verbena Polemoniaceae Boraginaceae Verbenaceae hastata bracteata Labiatae Salvia azure a Nepeta cataria Azure sage Catnip �163 Appendix B. Continued. Subclass Family Tribe Scientific name Common Solanaceae Physalis heterophylla Solanum americanum Solanum rostratum Scrophulariaceae Penstemon angustifolius Penstemon albidus Penstemon ambiguus Castilleja sessiliflora Orobanchaceae Orobanche ludoviciana Plantaginaceae Plantago patagonica Cucurbitaceae Cucurbita foetidissima Compositae Eupatorieae Liatris punctata Liatris squarrosa Astereae Chrysothamnus viscidiflorus Chrysothamnus nauseosus Chrysopsis villosa Grindelia squarrosa Solidago gigantea Solidago canadensis Solidago missouriensis Haplopappus spinulosus Conyza canadensis Erigeron diver gens Aster tanacetifolius Anthemideae Artemisia ludiviciana Artemisia filifolia Artemisia campestris Helenieae Palafoxia sphacelata Hymenopappus tenuifolius Helenium autumnale Heliantheae Ratibida columnifera Thelesperma megapotamicum Helianthus annuus Helianthus petiolaris Clammy groundcherry American nightshade Buffalobur nightshade Narrow-leaved penstemon White penstemon Gilia penstemon Downy painted-cup Louisiana broomrape \.loollyplantain Buffalogourd Dotted gayfeather Blazing star Douglas rabbitbrush Rubber rabbitbrush Hairy goldenaster Curlycup gumweed Giant goldenrod Canada goldenrod Missouri goldenrod Ironplant goldenweed Canada horseweed Spreading fleabane Common tansy-aster Louisiana sagewort Sand sagebrush Common sagewort Hooker palafoxia Old plainsman Sneezeweed Prairie coneflower Nippleweed Common sunflower Prairie sunflower �164 Appendix B. Continued. Subclass Family Tribe Scientific name Senecioneae Senecio longilobus Senecio fendleri Ambrosineae Ambrosia coronopifolia Inuleae Antennaria neglecta Anaphalis margaritacea Cynareae Cirsium vulgare Cirsium arvense Cirsium plattense Cichorieae Tragopogon dubius Tragopogon pratensis Lactuca scariola Nothocalais cuspidata Taraxacum officinale Lygodesmia juncea Common Threadleaf groundsel Fendler groundsel Western ragweed Field pussy toes Common pearlyeverlasting Bull thistle Canada thistle Platte thistle Yellow salsify Salsify .. Prickly lettuce Wavyleaf microseris Common dandelion Rush skeletonplant 1 �165 Colorado Division of Wildlife Wildlife Research Report April 1989 JOB PROGRESS REPORT State of: Colorado Project: W-152-R Upland Bird Research Work Plan: 17 Job Title: Population Period Covered: Author: Job _7_ Dynamics of White-tailed Ptarmigan 01 January through 31 December 1988 Clait E. Braun and Kenneth M. Giesen Personnel: Clait E. Braun and Kenneth M. Giesen, Colorado Division Wildlife of ABSTRACT Long-term studies of populations of white-tailed ptarmigan (Lagopus leucurus) were continued at hunted (Mt. Evans) and unhunted (Rocky Mountain National Park) areas in Colorado through 1988. Densities of breeding ptarmigan increased at Mt. Evans but decreased at Rocky Mountain National Park. Nesting success at both sites was good to excellent and brood size increased at Mt. Evans. There was no known harvest at Mt. Evans in 1988 because the highway was closed due to road construction. Apparently, no hunters walked the 3+ km into areas where ptarmigan were known to occur. ��167 POPULATION DYNAMICS OF WHITE-TAILED PTARMIGAN Clait E. Braun and Kenneth M. Giesen Long-term studies of trends in population size and investigation of reasons for fluctuations in size of tetraonid populations are lacking. Studies on the population dynamics of unhunted and hunted populations of white-tailed ptarmigan were initiated in Colorado in 1966 and have continued essentially uninterrupted at 2 sites. Studies of the unhunted population (Rocky Mountain National Park) identified possible short-term cycles of 7-8 years with an amplitude of 25-30% between high and low breeding densities. Conversely, studies of the manipulated population (hunted) at Mt. Evans have not indicated any cyclic pattern and it would appear that controlled hunting may mask any long-term trend that may occur. This study is designed to examine the question whether white-tailed ptarmigan are truly cyclic and whether hunting affects the apparent oscillations. P. N. OBJECTIVES The goals of this investigation are to be able to predict the length and amplitude of cycles in white-tailed ptarmigan in Colorado, to examine the impact of hunting on cycles, and to clarify underlying causes of the apparent cycles. SEGMENT OBJECTIVES 1. Conduct breeding (May-Jun) and brood (Aug-Sep) censuses ptarmigan using tape-recorded calls of males (breeding) (broods). 2. Censuses will be conducted on previously established, defined study areas at Mt. Evans (hunted) and at Rocky Mountain National Park (unhunted). 3. Capture (noose poles) and band (aluminum and plastic color-coded bands) all unmarked white-tailed ptarmigan encountered on study areas at Mt. Evans and at Rocky Mountain National Park. 4. Individually identify all ptarmigan observed on study areas at Mt. Evans and Rocky Mountain National Park through use of binoculars. 5. Make hunting season and bag limit recommendations for Mt. Evans and collect hunting data through use of volunteer wing barrels and hunter field checks. 6. Compile data, analyze results, and prepare progress of white-tailed and chicks reports. STUDY AREA AND METHODS Areas investigated were Mt. Goliath-Mt. Evans in Clear Creek County and at Tombstone Ridge-Sundance Mountain to Fall River Pass in Rocky Mountain �168 National Park in Larimer County. The physiography, geology, location, and vegetation of these study areas have been previously described (Braun 1969, 1971; Braun and Rogers 1971; Giesen 1977). Ptarmigan were located through use of tape-recorded calls (Braun et al. 1973), captured through use of telescoping noose poles (Zwickel and Bendell 1967) as described by Braun and Rogers (1971), and classified to age and sex and banded following Braun and Rogers (1971). Age of chicks was estimated following Giesen and Braun (1979). Numbered plastic bandettes were not used as in earlier years (Braun and Rogers 1971) as a color-code system using up to 4 different colored plastic bandettes was instituted in 1977-78. A check station was scheduled to be operated on the Mt. Evans highway during the opening weekend of the ptarmigan season in that area. A volunteer wing collection station was available to hunters in the area when the check station was not in operation until the season closed. RESULTS AND DISCUSSION Breeding Densities Mt. Evans.--Timing of breeding events in the Mt. Evans area was about 1 week earlier in 1988 than in 1987. During the May-early June interval, 14 pairs and 2 single males were identified. Thus, breeding densities increased from levels documented in 1986-87 (Table 1). This increase was primarily the result of territories on lower Mt. Goliath and west Mt. Goliath being occupied. During the breeding season, 8 of 16 males identified were yearlings while 9 of 14 hens were yearlings. Recruitment of yearlings was good in 1988. Rocky Mountain National Park.--Surveys of ptarmigan present on breeding territories along Trail Ridge Road in RMNP in May and June indicated the minimum breeding population was 30 birds, which was comprised of 12 pairs and 6 single males. This represents a slight decrease from the 33 birds (13 pairs and 7 single males) identified in 1987 (Table 1). The decreased breeding density reflect a return to average survival of adults and recruitment of yearlings. Survival of banded adults from 1987 was 53.2% (31 of 56 males, 11 of 23 females). Recruitment of chicks banded in 1987 was 18.6% (8 of 43) although yearlings comprised 33% of all adult ptarmigan identified in 1988. Nesting Success and Brood Size Mt. Evans.--Sixteen hens were located during mid July-early September 1987 on or immediately adjacent to the study area. Nine hens (56.3%) were with broods while 7 were apparently unsuccessful nesters (without chicks). Average brood size to 1 September was good (3.3 chicksjhen). Data from 29 chicks that were banded indicated hatch dates from 1 July to 9 August with only 34% hatching before 12 July. Rockv Mountain National Park.--Nest success was estimated at > 75% (all 9 hens observed in Aug-Sep were with broods). Hatch dates calculated from primary molt of chicks captured for banding indicated the median hatch date was 8 July (range 4 to 21 Jul). Average brood size to 1 September was 3.8 chicks. �169 Table 1. 1966-88. White-tailed ptarmigan breeding densities (birds/km2), Colorado Study area Year Rocky Mountain National Park (5.5 km2) Mt. Evans (4.0 km2) 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 11.3 9.8 11.5 12.0 9.6 9.1 8.7 7.8 8.0 11.1 l3.5 12.9 10.7 8.7 8.4 8.2 7.8 6.7 5.8 6.0 4.5 6.0 5.4 3.0 2.7 2.7 2.2 2.0 4.2 7.5 6.2 6.2 6.2 6.7 > 6.0 7.5 10.3 9.5 9.0 6.5 6.5 8.0 8.0 6.5 5.0 7.5 Harvest Mt. Evans.--The hunting season at Mt. Evans in 1988 opened on 17 September and closed on 2 October (16 days) with a bag and possession limit of 3 and 6. Thus, the season was delayed 1 week from the statewide opening as it was in 1981 and 1986-87. The season opening was delayed 2 weeks from 1978 to 1980 and 1982 to 1985. Prior to 1978, experimental seasons were in effect (19701976) or the season opened with the statewide grouse seasons (dates from 17 Aug to 14 Sep). While the season was open in 1988, the Mt. Evans road was closed (as in 1987) (gate) to all vehicular traffic because of road rebuilding above Ptarmigan Flats. Thus, no check station was operated on opening weekend but a volunteer wing collection station was in place on the highway throughout the season. No wings were received from ptarmigan, no birds were known to have been harvested, and no bands were reported. �170 LITERATURE CITED Braun, C. E. 1969. Population dynamics, habitat, and movements of whitetailed ptarmigan in Colorado. Ph.D. Thesis, Colorado State Univ., Fort Collins. l89pp. 1971. Habitat requirements of Colorado white-tailed West. Assoc. State Game and Fish Comm. 51:284-292. ptarmigan. Proc. _____ , and G. E. Rogers. 1971. The white-tailed ptarmigan in Colorado. Colorado Div. Game, Fish and Parks Tech. Publ. 27. 80pp. _____ , R. K. Schmidt, Jr., and G. E. Rogers. 1973. Census of Colorado whitetailed ptarmigan with tape recorded calls. J. Wildl. Manage. 37:90-93. Giesen, K. M. 1977. Mortality and dispersal of juvenile white-tailed ptarmigan. M.S. Thesis, Colorado State Univ., Fort Collins. 55pp. _____ , and C. E. Braun. 1979. A technique for age determination white-tailed ptarmigan. J. Wildl. Manage. 43:508-511. Zwickel, F. C., and J. F. Bendell. J. Wildl. Manage. 31:202-204. Prepared by Clait E. Braun Wildlife Research Leader Kenneth M. Giesen Wildlife Researcher B 1967. A snare for capturing of juvenile blue grouse. �iii Colorado Division of Wildlife Wildlife Research Report April 1989 JOB PROGRESS State of: Colorado Project: W-152-R Upland Bird Research Work Plan: 21 Job Title: Sandsage-Bluestem Period Covered: Author: REPORT Job _3_ 01 January Prairie Renovation through 31 December 1988 Warren D. Snyder Personnel: B. J. Hof and W. D. Snyder, Colorado Division of Wildlife ABSTRACT Precipitation was above average within the Tamarack Prairie during May and July 1988, below average during June, August, and October through December, averaging near to above normal for the year. Phenology was slightly behind that of 1986 and 1987 through April, but advanced rapidly in May and June. The 1984 controlled burns failed to increase the height-density index (HDI) of residual nesting cover. However, by spring 1988, the HDI had recovered to preburn levels. In contrast, the HDI of residual grass-forb vegetation within the 1985 and 1986 controlled burns, was greater than within the control transects in spring 1988 (f < 0.05). HDI among all samples increased dramatically from preceding years, apparently because of favorable precipitation and vegetative growth in 1987 and lack of heavy snow over winter. Crown cover of most warm season grasses increased within 1-2 years after the 1985 and 1986 burns but effects of controlled burns began diminishing by summer 1988. The HDI within the revegetation strips established in 1985 increased to 4.44 dm in spring 1988, far above that of burns or controls. Tall warm season grasses continued to increase in dominance along with their standing residual in these areas. The disk-harrowatrazine herbicide' renovation treatment,. applied in 1986 to a previously interseeded site, showed dramatic increases in HDI over controls along with increased crown cover of interseeded grasses. Impacts of spraying sand sagebrush (Artemisia filifolia) in 1985 could not be detected based on increased grass HDI nor crown cover sampling. However, the sprayed area burned in 1986 had dramatically greater grass HDI than controls in early spring 1988 (f < 0.05). Greater prairie-chickens (Tyrnpanuchus cupido) were observed several times during spring 1988 within the Tamarack Prairie in contrast to previous years when no birds were observed on the property. ��173 SANDSAGE-BLUESTEM PRAIRIE RENOVATION Warren D. Snyder P. N. OBJECTIVES Test renovation and revegetation techniques for increasing standing residual height-density of grasses, the proportion of tall warm-season grasses within the composition, and for reducing the quantity of sand sagebrush to < 30% canopy cover in an ungrazed sandsage-bluestem prairie on the South Tamarack, South Platte Wildlife Area in northeastern Colorado. SEGMENT OBJECTIVES Monitoring follows: of environmental and vegetation conditions and changes continued as 1. Precipitation was monitored throughout the year supplementing rain gauge data with information from nearby weather stations winter months. electronic through the 2. Soil moisture accumulations, plant phenology, and weather were monitored primarily in spring and especially at the time of controlled burns. 3. Visual obstruction (height-density) measurements were obtained treatments and controls where applicable in late winter and/or spring prior to green-up. 4. Crown cover, species composition, and frequency of occurrence measurements were obtained from mid-summer to early fall. 5. Photos of treatments and controls were taken in October. Data compilation and writing the annual job progress report was conducted during fall and winter 1988-89. on early METHODS Approaches used were described by Snyder (1986~, 1986g, 1987, 1988) and are outlined in the Segment Objectives. Segment Objective #4 was conducted within the 1985 and 1986 burn sites and their controls after not being conducted in 1987 and was deleted within the 1984 burns. RESULTS AND DISCUSSION Environmental Conditions Precipitation.--The 4 automatic precipitation recorders operated continuously through spring, summer, and fall 1988. Data from these recorders were supplemented from nearby weather stations during November through March. Precipitation recorded at 3 rain gauges near the north boundary of the study area was near to slightly. above average and ranged from 38.2 to 40.3 cm (15.05 - 15.86 in.). Precipitation at the southcentral rain gauge was 49.2 cm (19.38 �174 in.) with higher than average amounts in May and July. Rainfall in May and July for the entire area was above average but was markedly deficient in June when compared with the long-term mean (Fig. 1). 22 DOCT-OEC 20 18 ~SEP Ld 16 r. ~ALG Vl UJ I ~ v z 14 m...JUL 12 0 -f-c f- !=::·:·Ol...JUN 10 c, l.) ur a:: o, 8 6 _APR 4 2 _...JAN-MAR 0 x 84 85 86 87 88 YEARS Fig. 1. relation Monthly and annual precipitation (in.) from 1984 through to the long-term mean, Tamarack Prairie, Colorado. 1988 in Soil moisture, based on soil probe sampling, was favorable for vegetative growth throughout early spring (Table 1). Samples indicated> 5 cm of moisture was available through the early spring growing season. Table 1. Soil moisture accumulations (m)a based on soil probe spring 1988, Tamarack Prairie, Colorado. Location 4 West North-central South-central East 0.72 l.17 l.07 0.95 A r 18 0.61 l.11 0.95 0.93 aMean depth (m) of 4 probes/location precipitation gauges. samples during May 27 0.88 l. 30 l.19 0.78 4 1.11 l. 34 l. 36 1. 29 taken near each of the 4 22 1. 21 l. 34 1. 53 1.29 �175 Average monthly temperatures at Sterling indicated March through May were slightly warmer than average but June was 6.80 F above the long-term average (Fig. 2). Spring-early summer intervals since 1985 have averaged above normal whereas spring 1984 was colder than normal. Phenology of plant growth on 27 April 1988 (Table 2), when 2 controlled burns were conducted by management personnel on the Tamarack Prairie, was slightly behind that of 1986 and 1987. Based on mean average temperatures the phenology should have been similar to that in 1987 (Fig. 2). However, several hard freezes in mid to late April retarded vegetation growth. By mid to late May phenology was approximately the same as in 1987 (Table 2). 90 ~ • 80 MAY 1\ UL ~ JUN . APR 70 W IT ~ ~ ~ MAR 60 IT W ~ 2 w ~ 50 40 30 x 84 85 86 87 88 YEAR Fig. 2. Monthly average temperature (F) from March through June, 84-88 in relation to the long-term mean, as an index to vegetation phenology, Sterling, Colorado. �176 Table 2. Phenological conditions of selected vegetation during spring 1988, TamaracK Prairie, Colorado. Ma A r Species Artemisia filifolia ~. ludoviciana Astragalus sp. Cymopteris mont anus Evolvulus nuttalianus Lathyrus polymorphus Leucocrinum montanum Mentzelia nuda Penstemon ansustifolius Phlox andicola Psoralea lanceolata Sphaeralcea coccinea Tradescantia occidentalis Tragopogan sp. Agropyron smithii Bouteloua gracilis Calmovilfa longifolia Panicum virgatum Paspalum stramineum Sporobolus cryptandrus S t i pa .£Q!!!lli Cyperus sp. avegetation height (cm). E = early, M = medium, L Height-Density 18 27 04 22 E. budded Basal leaf Emerg. M. budded Basal leaf 5.0 L. budded 2.5 leaf 5-7.6 F. bloom 5-7.6 leaf 5-7.6 Bloom E. bloom F. bloom 05 s·7.6a Budded L. bud Bloom 2.5 5-10 10 E. bloom Basal whorl 5 5 Leafing Leafed 5 Leafed 5 5-7.6 5-7.6 Dormant Dormant Dormant Dormant Dormant 5-10 2.5-5 late, F 5-10 basal Leafed 5 2.5 20-25 E. bloom 10-15 15 7.6-10 10-12.7 2.5-5 Emerging Emerging 5 2.5-5 5 5 5 5-10 5-10 5 Emerging 10-12.7 Bloom 5-7.6 15 L. bloom 5-7.6 15-20 Headed < 7.6 5 L. bloom Headed 15 F. bloom F. bloom 7.6-10 Budded E. bloom Seeded 15-20 7.6-10 20 15-20 5-10 10 E. heading full. Sampling Within Burned Sites There was no evidence that the controlled burn conducted at site 1-84 in spring 1984 enhanced growth of grass-forb vegetation in subsequent years based on visual obstruction readings (VOR - HDI, Table 3, Fig. 3). Fire reduced the HDI but a full recovery in relation to the controls was evident by spring 1988 (end of the 3rd growing season). Grass-forb HDI increased dramatically from previous years within both the burned and control transects, primarily because of above average precipitation during the 1987 growing season (Fig. 1). Lack of significant lodging of vegetation by winter snow cover was also a factor enhancing HDI in spring 1988. Sand sagebrush had almost completely recovered its original status in the burned site by spring 1988. Grasses recovered slowly through 1986 yielding a low HDI in late winter 1987 following controlled burning within the 3-84 burn site. This area was more sandy and contained a much higher density of competing sandsage than burn 184. A dramatic regrowth of grass-forb vegetation was noted during 1987 (Table 4, Fig. 4). Based on comparisons with 1984, pretreatment HDI of grass-forb vegetation had not completely recovered by early spring 1988 although it and sandsage were approaching complete recovery. There is no evidence that either of the 1984 burns enhanced standing residual nesting cover needed by nesting prairie grouse (Tetraoninae). There is no significant analysis of covariance change from preburn to 1988 status for either burn. �177 Table 3. Mean height·density (dm) within burn 1-84 and it's controls during spring 1984-88 intervals, Tamarack Prairie, Colorado. Years Grass/fb Burn Sandsage Combined Grass/fb Control Sandsage Combined 1984 1985 1986 1987 1988 0.256 0.134 0.232 0.208 0.589 0.856 0.313 0.358 0.526 0.836 0.372 0.162 0.256 0.258 0.627 0.253 0.295 0.301 0.224 0.587 0.814 0.687 0.643 0.847 1.045 0.334 0.355 0.368 0.309 0.622 £. Values 1984-88 1985-88 1986-88 1987-88 :e.e. 0.00 20.39a 7.37b 0.15 < < 0.60 1.33 0.22 0.32 0.01 9.82a 6.73b 0.10 0.010. 0.025. 0.6 O.S r-. ~ u >- 0.4 lll) z UJ 0 I I- I CONTROL 0.3 "'- .)3----~(.. (CJ , "- UJ J: 0,2 'BURN 0.1 o 84 B5 86 87 88 YEARS Fig, 3. Height-density (dm) of residual grass-forb vegetation from 1984 (pretreatment) to 1985-88 (post-treatment) within the 1-84 burn and control sites, Tamarack Prairie, Colorado, �178 Table 4. Mean height-density (dm) within Burn 3-84 and its controls during spring 1984-88 intervals, TamaracK Prairie, Colorado. Years Grass/tb 1984a 1985 1986 1987 1988 0.222 0.021 0.106 Burn Sandsage Combined Grass/tb Control Sandsage Combined 0.827 0.121 0.356 0.286 1.215 0.493 0.047 0.201 0.157 0.831 0.183 0.191 0.200 0.216 0.625 0.935 0.797 1.044 0.688 1.494 0.531 0.503 0.629 0.424 1.059 o.on 0.466 .E Values 1984-88 1985-88 1986-88 1987-88 5.68 2.89 1.73 0.70 3.n 0.85 0.13 1.27 0.19 0.02 0.89 0.00 apretreatment. 0.7 0.6 I I 0.5 I J J J ~ 0.4 (Jl z UJ o f I ~ 0.3 J (.:J CONTROL UJ ---......." I 0.2 ..,;'" - - - ~~ - - - 84 85 J..>.----;/) ... 0.1 o 86 87 88 YEARS Fig. 4. Height-density (dm) of residual grass-forb vegetation (pretreatment) to 1985-88 (post-treatment) within the 3-84 control sites, Tamarack Prairie, Colorado. from 1984 burn and �179 The 1985 and 1986 burns enhanced grass-forb HDI by early spring 1988 (Figs. 5, 6). Burning suppressed grass-forb HDI through the 1st growing season within the 1985 burns. The grass-forb HDI had recovered by the end of the 2nd growing season and was ahead of the controls by the end of the 3rd growing season. Mean grass-forb HDI within the burns in early spring 1988 was markedly greater than within the controls (Tables 5, 6, f < 0.01). Sandsage did not show this rate of recovery or enhancement of HDI (Table 5, f> 0.10). Thus, the combined vegetation HDI was not as dramatic as that for grass-forb alone. 0.8 f\ E D ~ ~ ~ ~ , ,, BURN , Z W 0 I I I ~ I ~ - ,, 0.6 I ~. I 0.4 , I W I I ---It-~ \ CONTROL 0.2 o 85 87 86 88 YEARS Fig. 5. Height-density (dm) of residual grass-forb vegetation from 1985 (pretreatment) to 1986-88 (post-treatment) within the 1985 combined burn and control sites, Tamarack Prairie, Colorado. �180 0.8 1\ E D ~ ~ ~ ~ BURN 0.6 ~ I ~ I I I Z W 0 I ~ I ~ 0.4 W I CONTROL 0.2 o 85 86 87 88 YEARS Fig. 6. Height-density (dm) of residual grass-forb vegetation from 1985-86 (pretreatment) to 1987-88 (post-treatment) within the 1986 combined burn and control sites, Tamarack Prairie, Colorado. The impact of burning on 1st year (1987) HDI was not as severe as in previous years apparently because of increased precipitation received in 1986 (Figs. 1, 6). The HDI within the 1986 burned sites by the end of the 2nd growing season was markedly ahead of that within the controls (Tables 7, 8). The burns attained greater HDI by spring 1988 than the controls in comparison to preburn sampling in 1985 and 1986 (f < 0.05) (Table 8). The recovery from 1987 to 1988 was even more dramatic (f < 0.005). Sandsage had not recovered from burning by early spring 1988 or within 2 growing seasons (Table 7). Because of the dominance of grasses over sandsage within the burns, the combined vegetation HDI also showed evidence of stimulation by fire. �181 Table 5. Mean height-density (dm) within 1985 burns and their controls during spring 1985-88 intervals, Tamarack Prairie, Colorado. Burn Year 2 Control z 3 2 3 z 0.374 0.325 0.322 0.511 0.346 0.280 0.376 0.775 0.158 0.180 0.156 0.443 0.323 0.277 0.325 0.644 0.872 0.828 0.925 1.070 0.615 0.745 0.560 1.732 0.537 0.767 0.648 1.253 0.627 0.771 0.670 1.317 0.444 0.391 0.383 0.581 0.369 0.335 0.393 0.859 0.323 0.465 0.411 0.878 0.380 0.382 0.394 0.782 GRASS-FORB 1985a 1986 1987 1988 0.507 0.138 0.419 0.780 0.381 0.119 0.472 1.028 0.180 0.053 0.244 0.667 0.379 0.110 0.408 0.877 SANDSAGE 1985a 1986 1987 1988 1.008 0.417 0.523 0.938 0.679 0.342 0.591 1.167 0.642 0.438 0.769 1.144 0.744 0.388 0.672 1.125 COMBINED 1985a 1986 1987 1988 0.565 0.142 0.425 0.786 0.407 0.130 0.476 1.037 0.302 0.088 0.330 0.766 0.429 0.124 0.426 0.899 apretreatment. Table 6. Height-density relationships controls among years, Tamarack Prairie, Vegetation between the 1985 burns Colorado. 1985-88 and their 1986-88 1987-88 17.29b l.47 6.80a l. 53 2.43 E VALUE Grass-forb Sandsage Combined 7.78b l. 31 3.53 3.04 PAIRED !. Grass-forb Sands age Combined ap b~ < 0.025. < 0.010. 7.39a 2.84 0.64a 13.34b 0.81 6.66a 14.8sb 0.74 l. 33 �182 TabLe 7. Mean height·density (dm) within 1986 burns and their controLs during spring 1985-88 intervaLs, TamaracK Prairie, Colorado. Burn Year 2 ControL 3 2 3 ~ 0.294 0.2IT 0.234 0.387 0.316 0.312 0.404 0.858 0.233 0.213 0.269 0.644 0.275 0.265 0.289 0.600 0.829 0.756 0.885 1.265 0.417 0.300 0.833 1.667 0.618 0.690 0.671 1.197 0.682 0.693 0.750 1.237 0.345 0.342 0.325 0.494 0.317 0.331 0.413 0.873 0.298 0.323 0.357 0.743 0.320 0.332 0.357 0.679 .! GRASS' FORB 1985a 1986a 1987 1988 0.326 0.304 0.120 0.543 0.314 0.337 0.437 1.359 0.259 0.256 0.202 0.824 0.292 0.290 0.226 0.855 SANDSAGE 1985 1986 1987 1988 0.621 0.838 0.169 0.904 0.375 0.500 0.250 1.000 0.395 0.650 0.250 1.194 0.566 0.793 0.189 0.945 COMBINED 1985 1986 1987 1988 0.421 0.470 0.127 0.616 0.315 0.339 0.434 1.355 0.272 0.281 0.204 0.834 0.335 0.367 0.224 0.863 a1985 and 1986 were both pretreatment years. Table 8. Height·density relationships controls among years, Tamarack Prairie, Vegetation 1985-88 E Grass·forb Sands age Combined between the 1986 burns and their Colorado. 1986-88 1987-88 4.58a 5.19 3.60 33.88C 0.19 5.69b 2.16 0.45 0.05 4.68a 1.45 5.37a VALUE 4.69a 1l.15a 3.31 PAIRED .t. Grass-forb Sandsage Combined ap < 0.05. cr. < 0.025. < 0.001. bf 2.14 0.76 1. 59 �183 Increased precipitation received in 1986 and 1987 (Fig. 1) was the probable reason for faster recovery of grass-forb vegetation in the 1985 and 1986 burns and the increased standing residual over-winter into early spring 1988. The 1985 and 1986 fires were phenologically later than those in 1984 which also may have been a factor. How long this enhanced HDI will persist remains to be seen. Height-density of grass-forb vegetation increased from pretreatment to 1988 intervals by an average of 0.54 dm within combined 1985-86 burn sites compared to an average increase of 0.32 dm within their respective controls (paired~, f < 0.05). In contrast, the HDI of sandsage increased more (f < 0.05) within the 6 controls (0.63) than within the burns (0.34). Thus, analysis of total vegetation did not detect a significant (f > 0.05) pretreatment to 1988 change. From 1st-year post-treatment to 1988 within the combined 1985-86 burn sites, grass-forb vegetation increased 0.69 dm contrasted to an 0.33 dm increase within the controls (f < 0.001). The recovery of sandsage within burned sites (0.75 dm) compared with controls (0.58 dm) was less dramatic (f> 0.05). Total vegetation within the burned sites increased 0.71 dm from 1st-year post-treatment to 1988 intervals vs. 0.56 dm within the controls (f < 0.001). Thus, grass-forb vegetation responded favorably to controlled burns in both 1985 and 1986 in contrast to results of the 1984 burns. Crown Cover, Composition, and Frequency of Occurrence Sampling Point frame sampling, conducted from 1984 through 1986, was resumed in summer 1988 within the 3 sites burned in 1985 and 3 sites burned in 1986. The 1985 burns represented 17 transects (432 samples/transect) and 17 control transects, whereas the 3 1986 burns contained 19 transects and 19 controls. Data on species crown cover, composition, and frequency of occurrence per burn site and combined burns (or controls) varied (Tables 9-12). Numbers of transects were not distributed equally among burns either year and comparisons among burn or control sites should not be made. Ignoring sites, mean tallies per transect are presented for the 1985 burns (Table 13) along with statistical values of crown cover relationships (Table 14). Data for the 1986 burns and their controls are also presented (Tables 15, 16). A general review by pertinent species or groups is presented below. Blue Grama.--Evidence of enhancement of blue grama was apparent from both the 1985 and 1986 burns, but enhancement occurred in the 2nd growing season for the 1985 burns, whereas it occurred in the 1st growing season within the 1986 burns (Tables 13-16). Greater precipitation in 1986 than in 1985 (Fig. 1) may have been the primary difference. Mean crown cover/transect began converging from 1986 to 1988 indicating burning enhancement of blue grama was being overcome with time and that enhancement was not sustained. Findings from the 1985 and 1986 burns compliment findings from burn 1-84 for blue grama (Snyder 1988). Blue grama composition ranged from 9.4 to 19.2% and was recorded within nearly all transects (Tables 9-13). Needle-and-Thread.--Burns in 1984, 1985, and 1986 all had the same impact as they retarded crown cover through the 1st post-treatment growing season. Within the 1985 burns, retardation continued through the 2nd growing season even though 1986 was an especially good year for growth and seed production. Thus, enhancement from burning was not sustained over time. Needle-and-thread was one the most abundant grasses with composition ranging from 17.2 - 22.1% and occurred on 100% of the transects (Tables 9-13). �184 Table 9. Crown cover (point frame), species composition (%), and frequency of occurrence of vegetation within treatment transects on 3 sites burned in 1985, Tamarack Prairie, August 1988. Crown Cover Category/species Bare ground Dead vegetation Bouteloua gracilis Stipa ~ Sporobolus cryptandrus Calamovilfa longifola Andropogon hallii Agropyron smithii Aristida sp. Panicum virgatum Bromus sp. Cyperus & Carex spp. Artemisia filifolia Opuntia sp. 144 980 162 213 97 331 26 23 2 16 1 33 2 3 Total Comp. Freq. Occur. 205 1,586 140 306 160 433 79 155 179 658 150 97 80 35 85 20 2 83 2 191 1 11 82 15 528 3,224 452 616 337 799 190 198 4 83 16 14 306 16 12.58 17.15 9.38 22.24 5.29 5.51 0.11 2.31 0.45 0.39 8.52 0.45 0.94 1.00 1.00 0.94 0.76 0.88 0.12 0.12 0.06 0.24 0.82 0.29 226 16 4 10 6 1 6 8 2 17 6.29 0.45 0.11 0.28 0.17 0.03 0.17 0.22 0.06 0.47 0.35 0.12 0.24 0.24 0.12 0.06 0.12 0.24 0.06 0.12 5 4 19 220 1 10 1 1 1 1 1 1 0.14 0.11 0.53 6.12 0.03 0.28 0.03 0.03 0.03 0.03 0.03 0.03 0.12 0.12 0.53 0.76 0.06 0.35 0.06 0.06 0.06 0.06 0.06 0.06 Ambrosia psilostachya Artemisia ludoviciana Tradescantia occidentalis Evolvulus nuttalianus Erigeron sp. Psora lea tenuiflora Physalis subglabrata Thelesperma megapotimicum Ipomoea leptophylla Mentzelia nuda 65 14 3 Helianthus petiolaris Croton texensis Chenopodium album Conyza canadensis Euphorba sp. Lactuca sp. Plantago purshii Pepidium densiflorum Cryptantha sp. Cirsium sp. Cichorium intybus Unidentified 1 4 5 34 4 2 2 1 4 161 16 2 2 5 2 9 156 4 1 8 6 4 2 5 30 1 2 • �185 Table 10. Crown cover (point frame), species composItIon (X), and frequency of occurrence of vegetation within 3 1985 control sites, Tamarack Prairie, August 1988. Crown Cover Category/species ~ , Bare ground Dead vegetation Bouteloua gracilis Stipa .£Q!!!ill Sporobolus cryptandrus Calamovilfa longifola Andropogon hallii Paspalum stramineum Agropyron smithii Muhlenbergia sp. Aristida sp. Koleria cristata Panicum virgatum Bromus sp. ~ & Carex spp. Artemisia filifolia ~. filifolia (dead) Opuntia sp. Ambrosia psilostachya Tradescantia occidentalis Evolvulus nuttalianus Phlox andicola Lathyrus polymorphus Erigeron sp. Psoralea tenuiflora Physalis subglabrata Thelesperma megapotimicum Sphaeralcea coccinea Lygodesmia juncea Mentzelia nuda Asclepias sp. Helianthus petiolaris Tragopogan sp. Croton texensis Chenopodium album Eriogonum ~ Conyza canadensis Euphorbiasp. Lactuca sp. Plantago purshi i Pepidium densiflorum Salsola kal i Cirsium sp. Polygonum sp. 148 884 148 251 91 262 38 1 15 2 3 Total Compo Freq. Occur. 226 1,569 115 409 199 275 34 5 134 352 539 80 73 109 64 82 726 2,992 343 733 399 601 154 6 151 2 4 2 3 12 19 554 35 36 9.46 20.22 11.00 16.57 4.25 0.17 4.16 0.06 0.11 0.06 0.08 0.33 0.52 15.28 0.97 0.99 1.00 1.00 1.00 0.88 0.47 0.12 0.82 0.06 0.06 0.06 0.06 0.06 0.35 0.82 0.53 0.41 77 27 18 3 8 9 3 29 30 5 1 3 3 10 1 13 106 2 166 7 28 1 3 7 8 4 2.12 0.74 0.50 0.08 0.22 0.25 0.08 0.80 0.83 0.14 0.03 0.08 0.08 0.28 0.03 0.36 2.92 0.06 4.58 0.19 0.77 0.03 0.08 0.19 0.22 0.11 0.47 0.47 0.24 0.12 0.06 0.18 0.06 0.24 0.29 0.12 0.06 0.06 0.06 0.18 0.06 0.24 0.41 0.06 0.59 0.18 0.35 0.06 0.12 0.24 0.18 0.12 2 2 4 2 3 7 177 19 7 2 63 5 3 65 12 7 1 13 12 10 314 11 26 11 2 11 3 8 3 5 3 5 29 22 5 1 3 3 3 1 3 2 1 5 10' 1 12 103 163 1 26 1 2 6 7 4 2 1 2 �186 Table 11. Crown cover (point frame), species composition (X), and frequency of occurrence of vegetation within treatment transects on 3 sites burned in 1986, TamaraCK Prairie, August 1988. Crown Cover Category/species Bare ground Dead vegetation Bouteloua gracilis Stipa comata Sporobolus cryptandrus Calamovilfa longifola Andropogon hallii Agropyron smithii Aristida sp. Panicum virgatum Muhlenbersia sp. Bromus sp. Festuca sp. Cyperus & Carex spp. Artemisia filifolia ~. fi lifolia (dead) Opuntia sp. Ambrosia psilostachya Artemisia ludoviciana Tradescantia occidental is Phlox andicola Evolvulus nuttalianus Lathyrus polymorphus Erigeron sp. Psoralea tenuiflora Thelesperma megapotimicum Ipomoea leptophylla Mentzelia nuda Sphaeralcea coccinea Helianthus petiolaris Croton texensis Chenopodium album Conyza canadensis Euphorba sp. Lactuca sp. Pepidium densiflorum Cryptantha sp. Cirsium sp. Salsola Kali 426 1,041 321 291 130 263 133 21 2 3 Total Compo Freq. Occur. 127 791 69 151 123 270 11 46 338 1,277 418 288 108 339 16 125 5 2 3 22 891 3,109 808 730 361 872 160 192 5 2 2 3 3 30 19.20 17.35 8.58 20.72 3.80 4.56 0.12 0.05 0.05 0.07 0.07 0.71 1.00 1.00 0.95 0.95 0.53 0.68 0.11 0.05 0.05 0.05 0.05 0.26 49 1 20 278 3 21 6.61 0.07 0.50 0.58 0.11 0.21 296 62 8 1 19 4 34 3 4 3 3 56 7.03 1.47 0.19 0.02 0.45 0.10 0.81 0.07 0.10 0.07 0.07 1.33 0.63 0.16 0.26 0.05 0.37 0.05 0.53 0.11 0.16 0.05 0.05 0.37 13 17 73 129 7 2 1 1 1 1 0.31 0.40 1.73 3.07 0.17 0.05 0.02 0.02 0.02 0.02 0.16 0.21 0.58 0.63 0.21 0.11 0.05 0.05 0.05 0.05 2 3 8 227 2 1 2 115 3 22 181 62 3 1 7 4 16 3 1 3 3 31 2 4 3 1 6 22 73 1 1 13 9 47 53 5 1 2 3 12 11 7 2 • �187 Table 12. Crown cover (point frame), species composition (%), and frequency of occurrence of vegetation within 3 1986 control sites, TamaraCK Prairie, August 1988. Crown Cover Category/species Bare ground Dead vegetation Bouteloua gracilis Stipa comata Sporobolus cryptandrus Calamovilfa longifola Andropogon hallii Agropyron smithii Muhlenbergia sp. Aristida sp. Panicum virgatum E:yperus & ~ spp. Artemisia filifolia ~. filifolia (dead) Opuntia sp. • Ambrosia psilostachya Artemisia ludoviciana Tradescantia occidentalis Evolvulus nuttalianus Phlox andicola Lathyrus polymorphus Erigeron sp. Psora lea tenuiflora Physalis subglabrata Thelesperma megapotimicum Sphaeralcea coccinea Lygodesmia ;uncea Penstemon angustifolius Croton texensis Chenopodium album Eriogonum .!!D.D.!:!!!l Conyza canadensis Euphorbia sp. Lactuca sp. Pepidium densiflorum Cryptantha sp. Polygonum sp. Argemone sp. Unidentified 250 1,324 327 286 68 630 11 6 2 3 Total Compo Freq. Occur. 114 688 63 290 95 257 19 21 296 1,351 199 349 205 347 24 53 8 4 660 3,363 589 925 368 1,034 54 80 8 4 7 42 553 11 56 14.07 22.10 8.79 24.71 1.29 1.91 0.19 0.10 0.17 1.00 13.21 0.26 1.34 1.00 1.00 1.00 1.00 0.47 0.68 0.05 0.11 0.05 0.05 0.79 0.26 0.68 86 20 30 9 4 2 9 4 5 12 40 3 1 2.05 0.48 0.72 0.22 0.10 0.05 0.22 0.10 0.12 0.29 0.96 0.07 0.02 0.26 0.11 0.58 0.26 0.11 0.05 0.21 0.11 0.21 0.16 0.11 0.16 0.05 11 59 1 111 9 26 8 1 1 1 1 0.26 1.41 0.02 2.65 0.22 0.62 0.19 0.02 0.02 0.02 0.02 0.21 0.63 0.05 0.63 0.21 0.32 0.11 0.05 0.05 0.05 0.05 7 170 7 22 2 2 80 6 2 18 2 4 1 1 2 9 3 20 2 6 1 3 3 7 9 41 39 6 23 1 42 382 4 32 6 20 6 5 2 5 3 2 3 20 3 1 12 69 3 �188 Table 13. Crown cover (mean point frame tallies/transect) for selected species and species groups among pre- and post-treatment samples within combined 1985 burns and their controls, Tamarack Prairie, Colorado, 1984-88. Species/category Bouteloua gracilis Stipa comata Sporobolus cryptandrus Calamovilfa longifolia Andropogon hallii Agropyron smithii Selected warm season Total warm season Total cool season Artemisia filifolia Comb. peren. forbs combined annual forbs Bare ground Dead vegetation 19843 28.5 31.4 4.8 36.8 1.7 0.6 39.4 72.7 32.1 22.5 4.4 4.1 30.9 260.1 Treatment 1985 1986 21.2 27.7 21.1 54.5 5.1 1.8 61.8 104.0 29.5 8.2 3.4 2.8 110.3 170.1 20.6 48.2 21.1 58.8 9.6 10.4 70.5 112.2 58.6 11.9 5.7 3.5 90.7 145.1 1988 1984 26.6 36.2 19.8 47.0 11.2 11.6 63.1 109.5 47.9 18.0 17.5 15.5 31.1 189.6 30.8 31.3 8.1 33.1 2.1 2.2 35.9 74.8 33.5 24.7 2.9 3.6 42.2 249.3 Control 1985 1986 21.9 55.2 22.7 28.5 4.1 3.5 32.8 77.4 58.7 22.6 2.1 3.5 47.1 217.9 10.5 67.2 22.1 26.4 4.6 11.0 31.1 63.8 78.2 23.8 4.2 4.2 67.7 187.9 1988 20.2 43.1 23.5 35.4 9.1 8.9 44.6 88.2 52.0 34.6 12.7 20.9 42.7 176.0 apretreatment. Table 14. Crown cover relationships for selected species and species groups among years, 1985 burns, Tamarack Prairie, Colorado. £. Value Species/category 8415-85 84~-86 8411-88 Bouteloua gracilis Stipa comata Sporobolus cryptandrus Calamovilfa longifolia Andropogon hallii Agropyron smithii Selected warm season Total warm season Total cool season Artemisia filifolia Combined perennial forbs Combined annual forbs Bare ground Dead vegetation 0.11 15.99c 0.46 17.11c 0.68 5.91b 4.70a 0.64 20.77c 5.65a 4.27a 1.12 0.06 1.74 0.00 8.00c 6.98b 0.07 1.69 4.93a 19.02c 18.19c 16.99c 30.01c 0.18 0.10 92.20c 32.35c 37.20c 41.44c 2.98 15.96c 0.19 0.34 30.10c 14.74c 3.78 8.98c 0.14 11.35c 0.00 0.70 0.44 1.09 6.96b 22.7Oc 9.77c 3.06 0.06 0.09 3.80 3.68 ap < 0.05. 0.025. cp < 0.010. dpretreatment. bp < 85-86 85-88 86-88 6.02b 5.34a 0.35 3.41 0.17 4.67a 0.22 0.50 9.65c 5.09a 0.19 1.08 13.62c 4.65a 0.04 1.00 0.60 11.51c 2.98 2.14 5.87b 0.06 3.60 0.06 0.00 0.68 23.25c 10.77c �189 Table 15. Crown cover (mean point-frame tallies/transect) for selected species and species groups among pre- and post-treatment samples within combined 1986 burns and their controls, Tamarack Prairie, Colorado, 1984-88. Species/category 1984~ Bouteloua gracilis Stipa ~ Sporobolus cryptandrus Calamovilfa lonsifolia Andropogon hsllii Agropyron smithii Selected warm season Total warm season Total cool season Artemisia filifolia Comb. peren. forbs Combined annual forbs Bare ground Dead vegetation 37.3 42.5 10.3 26.9 1.9 28.9 76.5 46.1 18.1 7.2 5.2 39.5 234.2 Treatment 1985~ 1986 36.1 40.0 13.7 25.3 2.4 4.3 27.6 77.4 44.2 16.2 4.7 1.6 41.1 241.4 38.1 38.5 24.5 44.9 6.8 9.5 51.7 114.3 47.9 7.9 15.4 3.2 182.4 57.2 1988 1984 42.5 38.4 19.0 45.9 8.4 10.1 54.4 115.9 48.5 14.8 25.9 12.9 46.9 163.6 40.6 28.1 4.6 39.5 0.6 40.1 85.3 29.1 14.4 5.1 3.1 28.9 263.9 Control 1985 1986 34.6 52.1 14.8 33.8 1.1 1.8 34.9 84.3 53.7 19.3 3.0 1.3 32.6 226.6 18.0 61.5 15.3 37.2 1.2 5.3 38.3 71.6 66.8 22.6 6.3 2.3 46.6 204.8 1988 31.0 48.7 19.4 54.4 2.8 4.2 57.6 108.0 52.9 29.7 11.7 12.2 34.7 177.0 apretreatment. Table 16. Crown cover relationships for selected species and species groups among years, 1986 burns, Tamarack Prairie, Colorado. f. Value Species/category Bouteloua gracilis S t i pa £Q!llill Sporobolus cryptandrus Calamovilfa longifolia Andropogon hsllii Agropyron smithii Selected warm season Total warm season Total cool season Artemisia filifolia Combined perennial forbs Combined annual forbs Bare ground Dead vegetation ap < bi) < c< 0.05. 0.025. 0.010. Pretreatment. i. 6.94b 14.35c 0.06 1.40 9.27C 4.21a 0.01 0.40 0.16 85d-86 85d-88 8.93c 6.14b 8.11b 17.00c 7.67b 2.59 0.34 0.01 0.27 2.30 0.79 1.04 2.43 0.05 6.46b 3.19 0.09 1.04 2.61 20.83c 28.62c 2.33 21.16c 4.26a 0.15 180.89c 137.04c 86-88 3.01 1.07 3.41 6.38b 0.61 1.74 8.44b 11.77c 2.18 5.39a 0.40 0.17 13.42c 3.32 �190 Prairie Sand Dropseed.--There has been no marked evidence that fire impacted this species either positively or negatively based on crown cover sampling of the burns and their controls. First-year stimulation of seed production was evident but crown cover was little affected. Composition ranged from 8.6 to 9.4% in 1988 and this species occurred in nearly every transect. Prairie Sandreed.--This species responded favorably to fire with increased crown cover and seedhead production during the first growing season after both the 1985 and 1986 burns. Enhancement continued through the 2nd growing season within 1985 burns, however, by 1988, enhancement that had occurred was mostly over (Tables 13-16). Composition varied more widely than that of the other dominant grasses (16.6 - 24.7%) but sandreed occurred in nearly every transect (Tables 9-13). Sand Bluestem.--Although this less abundant species increased from 1984 through 1988 within both 1985 and 1986 controls, controlled burns showed evidence of stimulating crown cover growth and seed head production. The response appeared similar to that for prairie sandreed except the major crown cover increase within burns occurred during the 2nd growing season following the 1985 burns and during the 1st growing season following the 1986 burns. Increased precipitation in 1986 probably complimented stimulation by fire. Impacts of 1985 fire enhancement apparently ended by 1988 as treatment and control means converged. Divergent means continued through 1988 within the 1986 burns (Tables 13-16). Sand bluestem ranged from 1.3 to 5.3% of the total composition within the 1985 and 1986 burns in 1988 and frequency ranged from 0.47 to 0.76. Selected Warm Season Grasses.--This group, dominated by prairie sandreed, included sand bluestem and occasional occurrences of switchgrass and sand paspalurn. Response was similar to that of the dominant species with declines (1985 burn) or less increase (1986 burn) (f < 0.05) of crown cover from 1986 to 1988 in contrast to increases within the controls (Tables 13-16). Total Warm Season Grasses.--This group included all species within the selected warm season group plus blue grama and sand dropseed. Response to fire appeared dramatic for 2 years following the 1985 burn and for at least 1 year following the 1986 burn (sampling was not conducted in 1987). However, by 1988 the impacts of the burns were greatly diminished and sample means were converging (Fig. 7). Composition of total warm season grasses ranged from 41.5 to 52.4% (Tables 9-13) with approximately 50% occurring in 3 of the 4 sites. Western Wheatgrass.--This cool season grass was often going into dormancy by the time sampling was conducted. Thus, some variation among years was probably due to moisture and sampling time variances. Controlled burns possibly stimulated growth of western wheatgrass, but sample sizes were relatively small and the data are questionable. Data over time indicate the species, like sand bluestem, may be increasing with deferment from grazing, or during years of above average precipitation. Western wheatgrass ranged from 1.9 to 5.5% composition and occurred within 68 to 88% of the transects (Tables 9-13). Total Cool-Season Grasses.--Needle-and-thread dominated over western wheatgrass and other cool-season grasses. Western wheatgrass did not show the same response to fire as needle-and-thread. Other cool season grasses were too scarce to provide meaningful data. Combined cool-season grasses represented 22.1 to 24.6 of the total vegetative composition within the 1985 and 1986 burns and controls. �191 120 110 100 IU W (J) z « 0:: l<, 90 (J) W I CONTROL ......J I _j « l- 80 Z --' « w 2 70 ". • '" I I ,, ,, , I I I ,, I • 60 I I 50 84 86 85 87 YEARS Fig. 7. Crown cover (R tallies/transect) of total warm season grasses from 1984 (pretreatment) to 1985-88 (post-treatment) within the 1985 combined burns and controls, Tamarack Prairie, Colorado. Sand Sagebrush.--Favorable moisture apparently enhanced growth of sandsage during the last 3 years as crown cover means within 1985 and 1986 control transects increased. The 1985 and 1986 fires were cooler than those in 1984, but were conducted phenologically later in spring. They therefore, potentially stressed sage plants more since leafing (and use of energy reserves) was more advanced than in 1984. Rapid sage regrowth immediately after burns did not occur in 1985 and 1986 as it had in 1984. However, most plants survived and by 1988 had made considerable recovery. Sandsage was more prevalent within the controls, representing 13.2 to 15.3% of the composition compared to 6.6 to 8.5% within the burned sites in 1988. It occurred on 58 to 82% of the transects. Combined Perennial Forbs.--There was no evidence that burning enhanced combined perennial forbs within the 1985 burns (Tables 13-14). However, fire seemed to �192 stimulate increased perennial forb abundance within the 1986 burns which carried through to 1988 (Tables 15, 16). Since sample sizes were small and species were diverse, results are uncertain. Combined perennial forbs represented 5.4 and 6.0% of the composition within the controls but 8.3 and 11.7% in the burns in 1988 (Tables 9-13). In general, perennial forbs increased on both burned and control sites since 1985. Some of this variation was due to varying weather conditions that stimulated different species in different years. Western ragweed, a seed producing perennial potentially important to prairie grouse, increased from 68 to 522 between 1984 and 1988 in burned areas. The increase from 49 to 163 within the controls was less dramatic. Small sample sizes prevented detection of significant differences if they existed, but there was evidence that fire stimulated increased occurrence in both 1985 and 1986. Western ragweed is a warm season species that attained little if any growth prior to the burns. Combined Annual Forbs.--In combination, annual forbs increased on all treatments and controls from 1986 to 1988. Horseweed was extremely abundant in 1987 (Snyder 1988) and while less common in 1988, was still dominant among annuals (Tables 9-12). Generally, in 1987, it was most prevalent on unburned sites that possessed considerable litter accumulation. It may be an indicator of changing range conditions as a result of long-term grazing deferment. However, its increased occurrence within unburned 1985 and 1986 controls was not evident in 1988. Lambsquarter ranked 2nd and most other annuals ranked far behind. Impacts of fire on abundance could not be detected. Bare Ground and Dead Vegetation.--The amount of bare ground within both 1985 and 1986 burns declined to, or near pretreatment levels by 1988. However, the amount of dead vegetation was still considerably below pre-treatment levels (Tables 13-16). Revegetation Treatments Tillage-Reseeding.--The average HDI in early spring 1987 was 1.83 dm, but 1 year later, it had increased to 4.44 dm within 12 transects sampled among 19 revegetation strips seeded in 1985 (f < 0.001). In contrast, the mean combined vegetation HDI's within proximal 1985 and 1986 burn site controls in 1988 were 0.78 and 0.68 dm respectively. The reseeded strips thus provided HDI's 6 - 7 times greater than adjacent native range. Dramatic increases in standing residual resulted primarily because of favorable precipitation in both 1986 and 1987 (Fig. 1). Crown cover changes for major vegetation groups among years (Table 17) within the revegetation strips varied. Bare ground declined rapidly whereas dead vegetation, primarily standing residual within the crowns of switchgrass, increased dramatically. Occurrence of seeded tall warm season grasses remained nearly equal to that of the previous year, but totals of other grasses declined. Perennial forbs increased in contrast to 1987, but a major increase was not evident and the increase was distributed among several species. Switchgrass and bluestems comprised 84% of the vegetation compos~t~on in 1988, up from 77% in 1987. One of the 12 transects was included within a burn conducted by management personnel in spring 1988. �193 Table 17. Crown cover among vegetation 12 1985 revegetation transects, Tamarack Vegetation/category Bare ground Dead vegetation/litter Dominant native grasses Lesser grasses and sedges Seeded tall grasses Sandsage and cactii Perennial forbs Annual forbs I i groups from 1985 through Prairie, Colorado. 1988 within 1985 1986 1987 1988 804 212 217 79 311 6 22 76 812 156 226 37 475 10 12 278 372 183 21 833 8 2 31 120 620 98 13 829 15 20 13 a Tillage Renovation of Interseeded Tracts.--Evaluation of vegetation changes within a site previously interseeded (1981-92) and partially renovated (disked, harrowed, treated with atrazine herbicide) in spring 1986 (Snyder 1987) continued in 1988. Whereas the HOI of residual grass-forb vegetation increased from early spring 1987 to 88 within the controls, that within the treated transects increased much more dramatically (f < 0.025, Table 18). Sandsage, which was much less abundant within the transects, made considerable growth within both the treatments and controls. Combined vegetation within the renovated portion of the site yielded an HOI about twice that of the control starting into the 1988 growing season indicating favorable response, primarily of grasses, to renovation. Crown cover of bluestems and switchgrass (primarily interseeded) in combination increased steadily within the controls from 1985 through 1988. With renovation, the 1985-88 increase was markedly greater (f < 0.005, Table 19). In contrast, prairie sandreed, another deep-rooted tall warm season grass present prior to interseeding, did not respond to renovation (f> 0.10). However, the species was not negatively impacted by renovation (Table 19). Other more shallow-rooted native grasses, including blue grama, sand dropseed, and needle-and-thread, were markedly reduced by renovation, an impact that continued through 1988 (f < 0.005). Perennial forbs were not abundant prior to renovation and, although they may have been set back temporarily, they showed evidence of complete recovery by 1988 (Table 19). The interseeded bluestem-switchgrass mix had been planted in furrows, approximately 1.07 m apart. While native vegetation had been disturbed by interseeding, it had recovered quickly to provide competition to the young interseeded bluestem and switchgrass seedlings. Renovation in 1986 removed much of the competing shallow-rooted vegetation while suppressing annual forbs. Prairie sandreed, deep-rooted like the seeded grasses, was not retarded, but responded poorly to renovation. Management personnel have used the disk-harrow-herbicide technique on numerous interseeded tracts on the Tamarack Prairie from 1986 through 1988. In every instance dramatic release of tall warm season grasses was attained. It is probable that this renovation technique could be repeated with good results in future years on tall warm season grass stands. �194 Table 18. Mean height-density (dm) of grass-forb, sandsage, and combined cover from pre- (1986) to post-treatment (1987-88) intervals between a tillage-herbicide and untreated control within a previously interseeded location, Tamarack Prairie, Colorado. Year Tillage-herbicide Control Grass-forb 1986 1987 1988 0.382 0.314 l. 554 0.393 0.271 0.551 Sandsage 1986 1987 1988 l. 234 0.227 1.136 0.696 0.608 l. 268 Combined 1986 1987 1988 0.544 0.375 0.677 0.579 0.306 1.525 Table 19. Average crown cover/transect of selected species and species groups from pre- (1985) to posttreatment (1986-88) intervals within tillage-herbicide renovation of an interseeded site and it's control, Tamarack Prairie, Colorado. Species/group AndroP9gon/Panicum Calamovilfa longifolia Bouteloua, Stipa, etc. Perennial forbs 1985 13.7 11.3 17.6 1.5 Tillage-herbicide 1986 1987 24.2 12.4 5.4 0.6 36.3 13.8 6.4 1.2 1988 1985 Control 1986 1987 1988 39.8 11.2 6.8 1.6 16.4 10.7 17.1 2.2 16.6 10.6 16.8 1.7 22.1 10.2 19.8 3.4 24.6 8.1 20.4 1.7 .E Values 85-88 Andropogon/Panicum Calamovilfa longifolia Bouteloua, Stipa, etc. Perennial forbs ae_ < 0.005. 51.93a 2.03 38.83a 0.03 86-88 3.54 0.34 �195 Strip Spraying of Sandsage The HOI of grass-forb residual vegetation increased from 0.27 dm in 1987 to 0.61 dm in 1988. The HOI of standing dead sandsage also increased from 0.80 dm in 1987 to 1.13 dm in 1988. Since the sage was dead and slowly deteriorating, increased HOI was attributed to increased grass-forb growth within the sage plants. Pretreatment HOI's were not obtained within the spray site so enhancement of grasses due to the spray treatment is unknown. No difference was detected from 1987 to 1988 when the HOI of grass was compared with that within burn 3-85 and 3-86 controls. However, th~t comparison is extremely weak and significant change would not be expected within several years post-treatment. Grasses within the portion of the 1985 spray site that was burned in 1986 made dramatic recovery in 1987 with favorable precipitation, and provided excellent residual cover (HOI = 1.13 dm) in spring 1988 (Table 20). Growth from 1986 preburn to 1988 for 4 spray-burn transects, when contrasted to 14 controls, showed marked impact of burning (f < 0.001). Grass HOI increased a full decimeter from 1987 to 1988. Table 20. Mean height-density (dm) within the 1985 sandsage spray site during 1986 and 1987 post-treatment intervals and preburn (1986) to post-burn (1987) intervals within a portion burned in 1986, Tamarack Prairie, Colorado. Years N Transects Grass-forb Sands age Combined 1985 SANOSAGE SPRAY SITE 1986 1987 1988 2 11 11 0.246 0.272 0.613 SANOSAGE 1986 1987 1988 4 4 4 0.879 0.800 1.127 0.468 0.469 0.737 0.713 0.333 1.250 0.404 0.129 1.133 SPRAY - 1986 BURN 0.279 0.122 1.131 Point frame sampling of 11 transects within the 1985 spray site was conducted at a later date in 1988 and vegetation was advanced phenologically over previous years. Increased occurrence of needle-and-thread and prairie sandreed, and declines of both bare ground and dead vegetation probably resulted (Table 21). The decline in cheatgrass brome was not influenced by time of sampling. Live sage plants, if present, were not recorded but a steady increase in prickly pear since 1985 was recorded (Table 21). Perennial forbs remained at approximately the same level as in 1987 and, while still below 1985 pretreatment levels, were not significantly lower. �196 Table 21. Crown cover (point frame) of vegetation and ground cover within 11 random transects during pre(1985) and post-treatment (1986-88) spring intervals within the June 1985 herbicide-treated sandsage spray tract, TamaracK Prairie, Colorado. Vegetation/cover Bare ground Dead vegetation Perennial grass Bouteloua gracilis Stipa comata Sporobolus cryptandrus Calamovilfa longifolia Other perennial grasses Annual grass Bromus tectorum ~sp. Pretreatment 1985 1986 402 1,425 529 1,324 536 1,083 387 990 142 194 34 51 148 510 46 65 15 312 425 106 53 19 307 683 161 120 15 117 4 116 7 38 10 4 70 Post-treatment 1987 1988 o Artemisia filifolia (alive) A. filifolia (dead) 436 112 1 259 287 ° 210 Opuntia & Echinocereus spp. 44 50 62 83 Perennial forbs Ambrosia & Artemisia spp. Tradescantia occidentalis Lathyrus polymorphus Psoralea tenuiflora Evolvulus nuttalianus Phlox andicola Allium textile Mentzelia nuda Leucocrinum mont anum Penstemon angustifolius Thelesperma megapotimicum Cymopteris montanus Abronia fragrans 5 18 114 55 6 4 2 12 1 2 2 2 1 9 77 22 123 17 121 1 1 1 6 1 8 Annua l forbs Croton texensis Chenopodium album Pepidium & Lesguerella sp. Cryptanthia sp. Tragopogan sp. Plantago ~ Salsola Kali Conyza canadensis Lactuca sp. Unid. forbs Wildlife Occurrence 1 6 1 7 1 1 3 4 24 3 2 1 2 1 2 3 1 On the Tamarack Prairie Greater prairie-chickens were observed several times during spring 1988 within the Tamarack Prairie although searches for grouse were not conducted. This was the 1st year that this species, which is the primary focus of management and research efforts, has been observed frequently within the Tamarack Prairie. Management personnel and research assistants have located several leks along the south property line of the Prairie. Thus far, no leks have been found on the ungrazed Prairie itself. In addition to wildlife species �197 reported as occurring within the Tamarack reports, short-eared owl (Asio flammeus), and Cassin's sparrow (Aimophila cassinii) Prairie in previous progress great horned owl (Bubo virginianus), were observed in 1988. LITERATURE CITED Snyder, W. D. 1986~. Sandsage-bluestem prairie renovation. Job Progress Rep., Colorado Div. Wildl., Wi1dl. Res. Rep., Fed. Aid Proj. 01-03-045 (W-37-R). Apr. :475-498. 1986Q. Sandsage-bluestem praLrLe renovation. Job Progress Rep., Colorado Div. Wildl., Wildl. Res. Rep., Fed. Aid Proj. 01-03-045 (W-37R). Apr. :499-525. 1987. Sandsage-bluestem praLrLe renovation. Job Progress Rep., Colorado Div. Wildl., Wi1dl. Res. Rep., Fed. Aid Proj. W-152-R. Apr. :331-356. 1988. Sandsage-bluestem praLrLe renovation. Job Progress Rep., Colorado Div. Wildl., Wildl. Res. Rep., Fed. Aid Proj. W-152-R. In Press. Prepared by Warren D. Snyder Wildlife Researcher ��Colorado Division of Wildlife Wildlife Research Report April 1989 199 JOB PROGRESS REPORT State of: Colorado Project: W-152-R Upland Bird Research Work Plan: 21 Job Title: Accipiter Nest-site Selection and Foraging Behavior shinned Hawks in Mature Aspen and Conifer Habitats Period Covered: Author: Job 01 January 4__ through 31 December of Sharp- 1988 Suzanne M. Joy Personnel: C. E. Braun, R. W. Hoffman, Colorado Division of Wildlife; R. T. Reynolds, U.S.D.A. Forest Service; R. L. Knight, S. M. Joy, Colorado State University ABSTRACT Eleven active accipiter nests were found between 27 May and 26 August. These included nests of 8 sharp-shinned hawks (Accipiter striatus), 2 Cooper's hawks (a. cooperii), and 1 northern goshawk (a. gentilis). Nest cover types ranged from total conifer (Picea and Abies spp.) (1 goshawk, 1 sharp-shinned hawk) to total quaking aspen (Populus tremuloides) (1 Cooper's hawk), with 4 sharpshinned hawk nests in insular stands of conifers surrounded by aspen. The remaining nests were in mixed aspen-conifer habitat. A live great horned owl (Bubo virginianus)/mist net array was most successful of 5 methods used as 7 sharp-shinned hawks were captured. Six hawks (4 females, 2 males) were radiomarked with back-pack mounted transmitters (~4% of body weight). Hawk activity was monitored between 0600 and 2000 MDT. Percent slow pulse rate differed (£ = .0005) between sexes during the fledgling period. Prey deliveries were monitored at 4 sharp-shinned hawk nests (3 in aspen, 1 in conifer). Mean time between deliveries was greatest during incubation at all nests and least_during the nestling period at 3 of 4 nests. Inter-prey delivery periods .d.idnot differ (~';;"0.76). between habitat .types. Remains of prey plucked at nest si t es were collected from the 11 accipiter nests. ��201 ACCIPITER NEST-SITE SELECTION AND FORAGING BEHAVIOR OF SHARP-SHINNED HAWKS IN MATURE ASPEN AND CONIFER HABITATS Suzanne M. Joy P. N. OBJECTIVES The objectives of this study are to (1) measure sharp-shinned hawk daily activity budgets in mature aspen and conifer overstory types, (2) compare sizes and taxa of prey delivered to sharp-shinned hawk nests in the 2 overstory types through the breeding season, (3) measure time between prey deliveries to nests in relation to breeding phenology and prey abundance in each overstory type, and (4) describe nest-site characteristics of sharpshinned hawks, Cooper's hawks, and goshawks. SEGMENT OBJECTIVES 1. Locate accipiter nests in Gunnison 2. Measure sites. 3. Capture, radiomark, shinned hawks. 4. Monitor sharp-shinned 5. Monitor frequency 6. Collect and sort accipiter 7. Begin reconstruction 8. Compile vegetative and topographic and Grand Mesa National characteristics and obtain morphological forests. at accipiter measurements nest from sharp- hawk daily activity. of prey deliveries to sharp-shinned hawk nests. prey remains. and identification of prey remains. and analyze data and prepare progress report. DESCRIPTION OF STUDY AREA Portions of Gunnison and Grand Mesa National forests in Gunnison, Delta, and Mesa counties were selected for study. The study area was bordered on the west by Colorado Highway 65, northwest by Colorado Highway 330 extending east to the border between Pitkin and Gunnison counties (northern border), east by the Ruby Range, and south by the southern border of Grand Mesa National Forest. Climax aspen stands and conifer communities exist between 2,750 and 3,200 m. Large (> 500 ha) and small (100-200 ha) stands of mature aspen and conifer were inventoried for presence of accipiter hawks. Principal conifers were subalpine fir (a. lasiocarpa), Engelmann spruce (f. engelmannii), and blue spruce (f. pungens). At lower elevations, forests contained large (100500 ha) clearings with low shrub, forb, and grass cover. Understory vegetation types varied greatly depending on elevation, slope, and aspect. Dominant forbs included butterweed groundsel (Senecio serra), white �202 geranium (Geranium richardsonii), Barbey larkspur (Delphinium barbeyi), whiteflowered peavine (Lathyrus leucanthus), and monkshood (Aconitum co1umbianum). Prominent low-growing plants included elk sedge (Carex geyeri), wild strawberry (Fragaria ova1is), yellow prairie violet (Viola nuttal1ii), and fringed brome (Bromus ciliatus). The shrub component consisted primarily of snowberry (Symphoricarpus spp.), common chokecherry (Prunus virginiana), and true mountainmahogany (Cercocarpus montanus). Plant names follow Weber (1976). Sheep and/or cattle grazing occurred on much of the area. All study sites had been grazed by the end of the field season. METHODS Ground searches for accipiter nests began in May and were periodically conducted throughout the 1988 breeding season. Mature aspen, conifer, and mixed aspen-conifer habitats near ephemeral (drainages, marshes) and permanent (streams, creeks, ponds) sources of water were searched. Search areas were selected from aerial photographs (1:24,000) and topographic maps (7.5 min series). Stands possessing characteristics of accipiter nest sites in western montane forests (Shuster 1976, Reynolds et al. 1982, Moore and Henny 1983, Fischer and Murphy 1987) were selectively searched, although "unsuitable" stands were also explored en route to more "suitable" stands. In addition, 4 sharp-shinned hawk nest sites occupied in previous years (1 in 1986 and 1987, 1 in 1986 but not 1987, and 2 in 1987) (R. Reynolds, pers. commun.) were examined. Active nest sites were identified by the presence of a nest, breeding pair, or plucking areas with recent signs of activity (e.g., feathers, fur, casts, feces, and molted accipiter feathers). Vegetation and physiographic characteristics were measured at nest sites of breeding accipiters. Habitat variables measured included: 1) nest tree species, height, and diameter at breast height (dbh) , 2) nest-site elevation, aspect, canopy cover, and slope (the latter 3 measured by point-centered quarter method) (Cottam et al. 1953), 3) nest height and directional exposure, 4) distance to water,S) 2-3 species of dominant understory vegetation, and 6) average stand age. Stand age was calculated by coring the nest tree and 3-4 randomly selected trees in the nest site, then counting and averaging the core rings (+10 yr for tree growth to breast height). Sharp-shinned hawk nest sites occurring in pure, mature aspen, and conifer cover types ~ 2 km from another cover type were used for radiomarking, because foraging sharp-shinned hawks generally do not travel> 1.5 km from the nest (Reynolds 1983). Visual observations and/or radiolocations (% per cover type) were used to confirm that hawks were foraging predominantly (~ 90%) in the designated cover type. I used variations of trapping methods described by Bloom (1987) to identify the most effective technique for capturing sharp-shinned hawks. Techniques included: 1) mist nets and dho-gaza traps placed 0.5-2.0 m upslope from plucking posts in flight paths of adults returning with prey, 2) prey (2-weekold chickens) tethered 0.3-0.7 m from the center of mist nests and dho-gazas at several locations in and around the nest site, 3) a ba1-chatri baited with -2-week-old turkey poults placed near adult perches in the nest site, 4) a plastic great horned owl decoy with tape-recorded call placed within 0.3-1.0 m from a dho-gaza, and 5) a live great horned owl tethered at the nest site 0.5 �203 m downslope from V-arranged mist nets. Nets and traps used in techniques 1-4 were set between 0530 and 0630 or 2000 and 2100 MDT and checked every 30-40 minutes during daylight hours. The live owl/mist net array was installed before 0430 (sunrise was at -0530) and monitored continuously from a blind. Immediately after capturing a hawk, it was weighed, measured (wing chord, tail length, stage of molt), classified to age and sex, leg banded, and fitted with a back-pack mounted (Kenward 1985) lithium-powered transmitter with a variable pulse rate. Transmitter packages weighed 4 and 7 g, which were ~ 4% of male and female body weights, respectively. Pulse rates were regulated by mercurytilt switches that responded to changes in posture. Horizontal postures resulted in a rapid pulse (2.5 beeps/sec for females, 3.5 beeps/sec for males), whereas vertical postures produced a slow pulse (1 beep/sec for females, 2 beeps/sec for males). Activity (flying, perching, preening, plucking, eating) was monitored indirectly by recording changes in signal rate. Efforts were made to distinguish flight from other rapid-pulse producing non-flight activities (preening, eating, plucking prey) by comparing signal patterns with data gathered while simultaneously observing sharpshinned hawks. Focal-animal sampling (Altmann 1974), where an animal is intensively observed for a given period of time, consisted of radio-monitoring each hawk during every other 10-minute period in a day. Sampling occurred between 0600 and 2100. When a transmitter signal was lost, the next 10-minute sequence began as soon as the signal was audible again, regardless of the previous monitoring sequence. Systematic monitoring in this manner was later abandoned due to sampling problems (e.g., bird's transmitter signal beyond range, equipment failure) that resulted in inconsistent and scarce monitoring periods. Signals were then monitored from the time found until lost. To learn whether periods of data collection were balanced through the day, total minutes monitored were plotted against time of day (hour) for each nest, sex, and stage of breeding phenology (nestling, fledgling, independence). Dependent variables (percent slow pulse rate, mean length of rapid and slow pulse rates, number of pulse changes per minute) were plotted as a function of time of day for nest, sex, and stage of breeding to learn whether response variables reflected monitoring intensity. A multivariate analysis of variance (~iner 1971) (MANOVA 1) was used to test for differences between nests, sexes, and hour (0600-1900) for the response variables (percent slow pulse rate was normalized using arcsin transformation). All response variables were weighted by total time monitored. No test for differences among stages of breeding phenology was made because data sufficient to run MANOVA 1 were obtained only from the fledgling period. Differences in activity between cover types (aspen and conifer) were not tested because only 1 nest in each habitat was monitored during the fledgling period. If variable cover type had been used in the model, any significant cover effect may have been due to nest differences instead. To learn whether manipulating the time variable would affect MANOVA results, the above model was used after consolidating the independent variable 'time of day' into 3 time blocks (0600-1000, 1100-1400, and 1500-1900) (MANOVA 2). Prey deliveries to 4 sharp-shinned hawk nests (3 in aspen, 1 in conifer habitat) were recorded through the breeding season. Prior to and after radiomarking, a nest-site observer was used to record deliveries by non- �204 radiomarked birds; however, prey deliveries by radiomarked birds could be ascertained from signal strength and direction and from instantaneous begging by the young (late-nestling and fledgling stages of breeding only). The following criteria were used to distinguish prey deliveries from non-prey related nest visits by non-radiomarked birds: Incubation 1. Male entered the nest site and called faintly ("keekee"). Female flew to meet him and returned 5-7 minutes later, perched near the nest, and cleaned her bill. 2. Male entered the nest site, female flew to meet him while begging persistently (long, whining "screech"). Flutter of wings coming together was heard (pair was presumed to have exchanged prey in air, as was occasionally observed). Female returned to the nest -5 minutes later. 3. Male entered the nest site and called faintly. Female flew in the direction of the male and was later observed plucking and eating prey. 4. During a cold, light rain or when another raptor was near the nest site, the female occasionally refused to leave the nest when the male arrived with prey and called faintly. These events were recorded as prey deliveries because delivery was attempted. Nestling 1. 1-3 above. 2. Female begged persistently from near the nest, male (calling faintly) entered the site. Multiple, intense begging calls were heard from the nest. Then all begging stopped. 3. Male entered the nest site and called faintly, 2-5 minutes later female flew to the nest and fed the young. 4. Male or female flew to the nest while young begged loudly. After the parent flew off, the young wrestled with and appeared to be eating something. Fledgling 1. Parent and fledgling met and appeared to touch talons in the air. fledglings later chased the fledgling that met the parent. Other 2. Fledglings, begging intensely, chased a parent that flew through the nest site. Later 1 fledgling was seen eating prey. 3. Begging by fledglings, which had been periodic and slow, suddenly increased in intensity and speed. Moments later, a fledgling flew through the nest site with prey in its talons. Siblings chased the fledgling. �205 I tested for differences in mean time between prey deliveries among stages of breeding phenology (incubation, nestling, fledgling) using a 3-factor ANOVA (Winer 1971) with habitat type, nest within habitat type [nest (habitat)], stage of breeding, and all possible interactions as independent variables. Nest (habitat) and nest x breeding phenology (habitat) were used as random effects error terms. The response variable was normalized using log transformation. Early in the study, efforts were made to identify incoming prey by taxon and/or species. However, prey composition was difficult to ascertain because food items were either plucked beyond recognition before being delivered or were transferred from male to female (or parent to young) in locations beyond view. Consequently, efforts to identify prey were abandoned. Remains of plucked prey and regurgitated pellets were collected from the 4 sharp-shinned hawk nest sites approximately once a week as well as prior to and after monitoring periods, and every 2-3 weeks at all other nests. Prey are currently being reconstructed, identified, and counted following Reynolds and Meslow (1984), wherein uneaten remains (retrices, remiges, bills, and feet of birds, and fur, tails, skull fragments, and feet of mammals) are matched and compared with museum specimens. RESULTS AND DISCUSSION Nest Sites Approximately 11, 5, and 5 days were spent searching for accipiter nests in contiguous conifer, aspen, and mixed aspen-conifer stands, respectively. Eleven nests were found between 27 May and 26 August, including 1 goshawk in conifer habitat, 2 Cooper's hawk in aspen and mixed habitats, and 8 sharpshinned hawk in aspen (4), mixed (3), and conifer (1) habitats. Of 4 sharpshinned hawk nest sites occupied in previous years, 1 was reused. Eggs in 4 sharp-shinned hawk nests hatched between 5 and 12 July (the remaining nests were found post-hatch). Assuming a 30-32 day incubation period (Reynolds and Meslow 1984), incubation was initiated in early June and egg laying in late May. Fledging at the 4 nests occurred between 22 July and 12 August. An average of 3 (SD - 0.5) fledglings were observed at the 8 sharp-shinned hawk nest sites. Some young may have dispersed or been depredated before being counted. All sharp-shinned hawk nesting attempts were successful. Nest-site characteristics were measured at 8 of 11 nests (Table 1). Time constraints precluded measuring all nests. Those not completed will be measured in 1989. Accipiter nest sites ranged from 2,180 to 2,897 m in elevation and 3 to 180 m from water. Goshawks nested closer to water and higher in elevation than other accipiters; however, conclusions based on 1 nest are weak. Preliminary evidence also suggests that sharp-shinned hawks nest farther from water and use smaller, shorter trees, and steeper slopes than congeners. Most sharp-shinned hawk nests (83%) were in mature (70-120 yr-old) stands; 1 nest (17%) was in a young (50 yr) stand. The goshawk and Cooper's hawk nested in stands of approximately 116 and 85 years in age, respectively. �206 Table 1. Nest-site, western Colorado. nest-tree, and nest characteristics Nest-site characteristics Variable Distance to water (m) Slope (%) ~ SD ~ SD Elevation, Accipiter m Sharp-shinned 2,180-2,861 hawk of accipiters 80 66 45 28 in Aspect NE (2), (n) NiJ (4) (n ~ 6) Cooper's hawk (n = 1) (n - 1) Goshawk 2,655 160 26 NE 2,897 3 17 SW Nest-tree characteristics Variable Height (m) Spec i.es" ~ SD Accipiter Sharp-shinned hawk (n - 6) Cooper's hawk (n - 2b) (n - 1) Goshawk Sharp-shinned = Goshawk hawk 30 10 1, 4 26 45.6 4 26 47.5 6 13 100 1 Exposure NE (2), SE (3) , S (1) 6) Cooper's 7 Nest characteristics Variable Height (m) Canopy cover (%) ~ SD ~ SD Accipiter (n 19 1 (3), 2 (2), 3 (1) Dbh (cm) ~ SD hawk (n - 1) (n - 1) 17 92 18 100 SW a1) (Abies 1asiocarpa), 2) (Picea enge1mannii), 3) (E. pungens), 4) (Populus tremu1oides). bNest-tree species was the only characteristic measured at 1 nest. �207 Nest height was greater for goshawk and Cooper's hawk nests than those of sharp-shinned hawks. Canopy cover at the nest tree did not appear to differ among species. Nest tree species and aspect, nest exposure, and cover type at the nest and surrounding the nest site varied among nests. However, sharpshinned hawks consistently nested in conifers (67% were in small, insular stands of conifers surrounded by extensive stands of aspen), whereas the goshawk nested in aspen and the Cooper's hawks in aspen and conifers. Dominant understory vegetation varied among nest sites. Sharp-shinned hawk nest-site characteristics were qualitatively compared with measurements of sharp-shinned hawk nest sites in other western states (Table 2). Sharp-shinned hawks in Colorado appear to nest in trees similar in height and dbh to nest trees in Oregon, but in taller and larger trees than in Utah. Nest height in Colorado was also within range of heights reported for birds in Oregon; however, sharp-shinned hawks in Colorado generally nested much higher in trees than did sharpshins in Utah. Differences between site characteristics of birds in Utah versus Colorado and Oregon may be the result of more deciduous trees at nest sites in Utah compared to primarily conifers at nest sites in Colorado and Oregon (Fischer and Murphy 1987). Table 2. Nest characteristics of sharp-shinned hawks in Colorado, Oregon, and Utah. Nest tree Nest sitea Canopy closure ~%l ~%l SO SO ~ Nest height ~ml so ~ Height ~ml SO ~ O~ ~ ~cml SO 12 7 19 7 30 10 38 18 96 4 This study 18 6 27 6 41 21 26 9 80 90 14b 9c Reynolds et al. (1982) E Oregon n = 10 13 4 11 6 23 13 25 16 ~ 24 Reynolds et al. (1982) NE Oregon n = 15 8 3 29 14 25 19 98 2d Moore and Henny (1983) Utah 3 18 4 19 6 82 7 Fischer and Murphy (1987) Location Colorado n= NW Slo~ ~ 6 Oregon = 6 n n Source = 9 9 2 aMeasured using (1) point-centered quarter method in this study and Reynolds et al. (1982), (2) point sampling along transects in 4 cardinal directions in Moore and Henny (1983), and (3) variations on methods 1 and 2 igs:~~~e;r~~h~U~~Y3~1987). COld growth, n =-2. dNest tree only. Slope gradient appeared steeper and canopy cover more dense at nest sites in Colorado than at nests in Utah and Oregon, with the exception of canopy cover reported by Moore and Henny (1983), which was for the nest tree only. In the studies examined, a majority of sharp-shinned hawks nested in sites with northerly aspects. Nests in Colorado were usually built on southeasterly exposures (Table 1, Fig. 1); however, in Utah and northeastern Oregon nest placement was random. Reynolds et al. (1982) reported a tendency towards southeast to southwest nest placement for hawks in northwestern and eastern Oregon. �208 w Fig. 1. Colorado. Directional exposure • of sharp-shinned • • • • • hawk nests in western Trapping Trapping occurred between 14 June and 24 July. Trapping techniques 1-4 (discussed in methods) were unsuccessful. When nets were placed in the path of ground-based plucking areas, the hawks plucked their prey in nearby trees. Prey tethered in front of mist nets were sometimes attacked, killed, and plucked, but hawks avoided the nets when approaching and leaving the site. Male sharp-shinned hawks appeared interested in the bal-chatris baited with turkey poults (observing and/or swooping by it), but only 1 male made contact with the trap. He escaped as I approached. No hawk reacted to the plastic great horned owl decoy. These trapping methods were used alone or in combination for nearly 6 weeks. Several possible unsuccessful: explanations exist for why capture methods 1-4 were 1. Hawks saw the nets and avoided them. 2. Nesting pairs were unaccustomed to hunting near the nest and suspicious of immobile, conspicuous prey placed there. Natural prey were relatively scarce at nest sites, due to either hunting pressure or nest-site avoidance. Consequently, hawks may have learned (or evolved) to hunt away from the site. �209 3. Prey used behavior. (domestic 4. The plastic fowl) were not appropriate owl decoy was not realistic stimuli and, therefore, for hunting posed no threat. Seven sharp-shinned hawks (4 females, 3 males) were captured in 4 days using a live great horned owl with V-arranged mist nets. Six were radiomarked; 1 male escaped after being weighed and could not be retrapped. During trapping, if the owl was seen from the nest, the female attacked it at first light (-0545). Males usually did not see the owl until the second prey delivery of the morning (0600-1000). One nest was in the early-nestling and 3 were in latenestling stages of breeding phenology when trapping occurred. Most birds were processed and released within 30-45 minutes of capture. Wing chord and tail length measurements were similar to those reported by Mueller et al. (1979) for birds trapped in Wisconsin and to wing chords of museum specimens reported by Storer (1966). Females had larger wing chords, longer tails, and weighed nearly 77% more than males (Table 3). Stage of molt varied among birds, but females tended to be farther along in their molt sequence than males. All radiomarked birds flew well upon release. Table 3. Measurements of sharp-shinned Male SD Measurement Weight, g Right wing chord, em Left wing chord, em Tail length, em Sharp-shinned hawks captured 103.3 17.8 17.7 3.1 0.3 0.1 14.6 in Colorado, R 3 2 2 1 182.5 20.7 20.8 15.5 1988. Female SD 8.9 0.5 0.3 0.9 on 4 4 4 4 Hawk Activity Six birds were radiomarked, including 2 nesting pairs (1 in aspen, 1 in conifer habitat) and 2 females in aspen habitat (1 female lost her transmitter after 1 week and could not be retrapped). At the latter 2 nests, I was unable to trap 1 male and could not retrap the other after it escaped. Data were collected only for the fledgling period at 2 nests (where the pairs were radiomarked) and the nestling period at 1 nest (female only) because birds were radiomarked late in the breeding season and nests were at different stages of breeding phenology. At the nest where data were obtained for the nestling period only, young fledged nearly 10 days later than other nestlings. In addition, the female lost her transmitter prior to or just after the young fledged (I believe she removed it while preening). All females lost their transmitters before the end of the field season. Females were perhaps better able to weaken and remove transmitter harnesses because they devoted less time to foraging than males and more time to preening (S. Joy, pers. observ.). Presently, I am designing a more durable transmitter harness that will weaken and falloff within 2-3 months of placement on the bird. �210 Initial efforts to distinguish flight from other non-flight, rapid-pulse producing activities were abandoned. Only 1 female was observed and simultaneously radio-monitored during the field season. Generalizations made from her behavior to the sharp-shinned hawk population would be biased. Other females were more secretive and male visits to the nests were too brief to allow behavioral observations. Plots of total minutes monitored per hour of daylight for each nest, sex, and stage of breeding phenology (nestling, fledgling, independence) revealed that most periods of data collection were not evenly distributed through the day or within categories. Lack of balanced categorical sampling was due to (1) an inability to trap hawks until late in the breeding season and (2) female transmitter removal, whereas lack of balanced monitoring through the day was due to (1) an inability to receive a bird's signal at certain times of day, (2) receiver failure, and (3) abandonment of systematic sampling. In the 1989 field season, charts of telemetry sampling effort will be maintained to ensure balanced sampling. Response variables plotted against time of day revealed that response values reflected monitoring intensity. Dependent variables were therefore weighted by total time monitored. Due to sampling problems and the monitoring scheme change, 20-46% of the total time hawks were monitored consisted of incomplete signal bouts. That is, the first and last signals received during a monitoring period were often truncated. As a result, the response variables (mean length of rapid and slow pulse rates) were biased by the length of time a hawk was monitored. During the 1989 field season, telemetry equipment and techniques will be improved so that fewer signals are lost, and the monitoring schedule will be altered (each bird will be monitored intensively for 3-hour periods; Appendix A) so that unbiased estimates of the variables will be obtained. Sex contributed significantly to MANOVA 1 for dependent variables (1) percent slow pulse rate and (2) mean length of slow pulse rate (Table 4). During the fledgling period, females spent more time perching than males (Table 5). No other main effects or interactions were significant. Consolidating time of day into 3 time blocks improved the strength of the model (MANOVA 2, Table 6) -- sex and nest, as well as some interactions involving sex, nest, and hour contributed significantly to the model. Blocking in this fashion, however, is subjective. One may achieve desired levels of significance by simply manipulating the size of the time block. Neither model is adequate given that monitoring period lengths varied greatly during 1988. Ideally, length of the time variable should be determined by a monitoring period length that is constant for all birds (see monitoring schedule proposed for 1989, Appendix A). A revised MANOVA model, one in which the time of day variable is determined by monitoring period length, will be used to analyze data collected during the 1989 field season. Nest differences in activity appeared to be small (Table 4). If nests (1 of which was in aspen and the other in conifer habitat) were at all indicative of habitat differences, numerous samples (> 10; G. White, pers. commun.) in each habitat would be required to detect significant habitat differences in activity. It is not feasible to radio-monitor at a large number of nests. Consequently, null hypothesis Ha in the Program Narrative addressing habitat differences in activity will be abandoned. Differences between sexes (Tables 1 �211 Table 4. MANOVA 1 -- measures of sharp-shinned hawk activity with nest, sex, time of day (hour), nest x sex, nest x hour, sex x hour, and nest x sex x hour as the effects. Source of variation df ss I f Percent slow pulse rate&,b Nest Sex Hour Nest*sex Sex*hour Nest*hour Nest*sex*hour Error 5.75 25.98 9.93 0.33 6.09 13.72 15.06 49.56 1 1 l3 1 11 11 8 29 3.36 15.20 0.45 0.19 0.32 0.73 l.10 0.08 0.0005* 0.94 0.66 0.97 0.70 0.39 Mean length slow pu1sea r Nest Sex Hour Nest*sex Sex*hour Nest*hour Nest*sex*hour Error 1 1 13 1 11 11 8 29 32326.82 1189976.78 294573l. 89 241603.36 2653564.49 2574733.80 302l386.96 7783310.33 l.61 4.43 0.84 0.90 0.90 0.87 l.41 0.21 0.04* 0.61 0.35 0.55 0.58 0.24 l.89 2.78 0.23 0.60 0.40 0.20 0.60 0.18 0.11 0.996 0.45 0.94 0.996 0.77 0.04 3.80 0.44 0.78 0.60 0.63 0.89 0.84 0.06 0.94 0.39 0.81 0.79 0.54 Mean length rapid pu1sea Nest Sex Hour Nest*sex Sex*hour Nest*hour Nest*sex*hour Error 1 1 13 1 11 11 8 29 12889.63 18962.43 20519.43 4078.84 30296.54 15l32.32 32863.79 191166.98 Activity changes Imina Nest Sex Hour Nest*sex Sex*hour Nest*hour Nest*sex*hour Error 1 1 l3 1 11 11 8 29 *f < 0.05. aWeighted by total time monitored. bArcsin transformed. 1.40 120.17 18l.18 24.55 209.31 217.65 225.27 918.05 �212 Table 5. Activity measures for male and female sharp-shinned hawks during nestling, fledgling, and independence stages of breeding phenology. Phenology Nestling Sex (,n) Female (3) n Variable & SD Slow pulse Slow pulse Change rate 87.25 10.90 178.03 l.4l 11.22 7.23 231.95 l.22 Slow pulse Rapid pulse Slow pulse Change rate 5l.37 24.48 19.56 2.84 24.69 16.98 9.11 0.96 Slow pulse 90.00 8.28 117.67 l.41 9.36 7.23 115.16 0.76 Slow pulse Rapid pulse Slow pulse Change rate 64.94 19.25 42.30 2.45 15.23 13.69 4l. 32 l.08 Slow pulse R Rapid pulse R Slow pulse Change rate 76.45 28.20 134.38 l.64 23.29 34.19 162.40 l.61 Observ. 18 % & Rapid pulse R Male (2) 7 % R R Fledgling Female (2) 23 % ~ Rapid pulse ~ Slow pulse Change rate Male (2) 24 % R R Independence Male (2) 22 % , �213 Table 6. MANOVA 2 -- measures of sharp-shinned hawk activity with nest, sex, time of daya (hour), nest x sex, nest x hour, sex x hour, and nest x sex x hour as the effects. Source of variation df ss Percent slow pulse rateb,c Nest Sex Hour Nest*sex Sex*hour Nest*hour Nest*sex*hour Error 1 1 2 1 2 2 2 64 13.57 64.04 6.39 l.67 l.22 5.82 8.57 82.56 10.52 49.65 2.48 l.29 0.47 2.26 3.32 0.002* 0.0001* 0.09 0.26 0.62 0.11 0.04* 11.70 23.06 3.05 6.86 5.03 2.23 4.19 0.001* 0.0001* 0.05 0.01* 0.009* 0.12 0.02* Mean length slow pu1seb Nest Sex Hour Nest*sex Sex*hour Nest*hour Nest*sex*hour Error 1 1 2 1 2 2 8 64 2980305.86 5874996.18 1553897.32 1747778.94 2562400.62 1135556.72 2133912.13 16308256.04 Mean length rapid pu1seb Nest Sex Hour Nest*sex Sex*hour Nest*hour Nest*sex*hour Error 1 1 2 1 2 2 2 64 33211.87 53115.34 9155.07 15065.46 9707.89 3337.40 8017.61 398478.48 5.25 8.40 0.72 2.38 0.77 0.26 0.63 0.03" 0.005* 0.49 0.13 0.47 0.77 0.53 Activity changes /mi.n" Nest Sex Hour Nest*sex Sex*hour Nest*hour Nest*sex*hour Error 1 1 2 1 2 2 2 64 5.22 334.97 7l.19 76.62 155.22 12.48 53.72 1756.68 0.19 12.20 l.30 2.79 2.83 0.23 0.98 *~ < 0.05. aMeasured in 3 time blocks (0600-1000, 1100-1400, 1500-1900). bWeighted by total time monitored. cArcsin transformed. 0.66 0.0009* 0.28 0.10 0.07 0.80 0.38 �214 4, 6) and breeding phenology (Table 5), however, the following null hypotheses will be tested: appear strong. Therefore, Hol: Percent time spent perching, mean length of rapid and slow pulse rates, and activity changes/minute do not differ between sexes or among nests, males, females, or incubation, nestling, and fledgling stages of breeding phenology. Ho2: Diurnal patterns of activity do not differ between sexes or among nests, males, females, or incubation, nestling, and fledgling stages of breeding phenology. Prey Deliveries Frequency of prey deliveries were recorded during each nest visit. During early stages of nesting (incubation, early-nestling), males delivered prey to females at the nest site. The female in turn plucked and ate or fed the prey to the young. As the nesting season progressed into late-nestling and fledgling stages, females were often away from the nest and males delivered prey directly to the young. Females also provided the young with food at this time. Prey deliveries rates did not differ among stages of breeding phenology (Table 7). However, deliveries appeared least frequent during incubation at all nests, and most frequent during the nestling stage at 3 of 4 nests (Fig. 2, Table 8). This trend, which reflected greater foraging effort by males and the initiation of foraging by females, did not differ (£ - 0.76) between aspen and conifer habitat types (Table 7). At nest BR (aspen habitat), where prey deliveries were most frequent during the fledgling stage, young were fed primarily by a subadult male until post-fledging, when the female began to consistently supplement prey deliveries. The BR male seemed less competent than adult males at other nests, as he would often fail to return for long periods or returned without prey. Prey deliveries occurred over 3 times more often during the nestling than incubation period (Table 8). At 3 of 4 nests, prey delivery rates decreased slightly during fledgling stages (Table 8). Contributions by habitat x breeding phenology and nest x breeding phenology (habitat) interactions were insignificant (Table 7). Habitat differences in prey delivery rates will be difficult to detect given a reasonable number of nests; therefore, null hypothesis Hb of the Program Narrative addressing habitat differences will be replaced by the following: Ho3: Mean time between prey deliveries does not differ among nests or incubation, nestling, and fledgling stages of breeding phenology. Food Habits Prey remains were collected from all accipiter nest sites found (62 sampledays). Approximately 35 sample-days of prey have been sorted by probable species. Avian prey from 1 sharp-shinned hawk nest in conifer (9 sample-days) and miscellaneous avian samples from 3 nests in aspen (-5 sample-days/nest) were identified. Few prey species were cornmon at both nest sites (Table 9), 'Twice as many species appeared in the diets of birds in aspen than birds in conifer habitat (Table 9). This trend may be biased by the greater number of �215 Table 7. Three-factor ANOVA nests during the 1988 breeding type [nest(habitat)], breeding and all possible interactions and nest x brphen8(habitat) as Source for prey delivery rates to sharp-shinned hawk season with habitat type, nest within habitat phenology (incubation, nestling, fledgling), as the effects. The model uses nest(habitat) random effects error terms. of variation df MS .E f Habitat Error [nest (habitat) ] 1 4.18 0.02 0.15 0.10 0.76 Nest(habitat) Error [nest*brphen 2 6.11 0.16 0.26 0.60 0.58 (habitat) ] Brphen Error [nest*brphen 2 5.42 1. 20 0.28 4.35 0.07 (habitat) ] Habitat x brphen Error [nest*brphen 2 5.74 0.04 0.27 0.13 0.88 (habitat) ] 0.32 0.15 2.20 0.07 Nest x brphen Error aBreeding (habitat) phenology. 1.2 1.0 0: I 4 152 .~. RA BZ Clf BR ASPEN HABITAT D . CONIfER HABITAT 0.8 <, (f) w - 0: 0.6 W > .....J W 0 0.4 INCUBATION NESTLII'-t:; FLECGLING STAGES OF BREEDING PHENOLOGY Fig. 2. Prey delivery rates of sharp-shinned hawks to nests in aspen and conifer habitats as a function of breeding phenology. (Total hours of observation are at the top of each bar). Nest acronyms stand for the nearest source of water to which nests were located: RA (Ruby Anthracite Creek), BZ (Buzzard Creek), BR (Bird Creek), CW (Cow Creek). �216 Table 8. Mean time (min) between prey deliveriesa nests during the 1988 breeding season. Stage of breeding BZ RA :& SD :& SD to sharp-shinned Nestb BR SD :& :& 208 128 (9, 47) 185 (2, CW SD hawk Total SD :& Incubation Hrd) (n 350 (2, 149 17) 262 (3, Nestling (n, Hr) 66 (38, 78 48) 85 (21, 70 39) 93 (26, 70 54) 67 (12, 28 17) 70 77 (97, 158) Fledgling (n, Hr) 91 (18, 74 38) 175 147 (6, 28) 71 (16, 77 23) 94 (11 , 65 24) 95 87 (51, 113) C , 76 24) 113 21) 233 121 (16, 109) aMeasured to the nearest 5 min. bNest acronyms stand for the nearest source of water to which the nest was located: RA (Ruby Anthracite Creek), BZ (Buzzard Creek), BR (Bird Creek), CW (Cow Creek). cNumber of inter-prey delivery bouts. dHours of observation. nest sites sampled in aspen habitat or the unique plucking habits of birds in either habitat. Sorting and identification of mammalian and avian remains and regurgitated pellets continue. Differences in prey composition (size, taxon) between habitat types and stage of breeding phenology (incubation, nestling, fledgling) appear to exist; therefore, null hypothesis Hc of the Program Narrative will be replaced by the following: Ho4: Composition and number of prey delivered to nests do not differ between mature aspen and conifer habitat types or among incubation, nestling, and fledgling stages of breeding phenology. �217 Table 9. Avian prey at sharp-shinned hawk nest sites in aspen and conifer habitat during the 1988 breeding season. Common name Scientific lSapsucker spp. lDowny woodpecker 2Violet-green swallow 2Western flycatcher Mountain chickadee 2Black-capped chickadee Brown creeper House wren American robin lTownsend's solitaire Hernmit/Swainson's thrush Golden-crowned kinglet 2Solitary vireo Yellow-rumped warbler 2Yellow warbler lEvening grosbeak 2House sparrow Pine siskin lGreen-tailed towhee 2Vesper sparrow 2Song sparrow 2Black-throated sparrow Dark-eyed junco White-crowned sparrow 2Lincoln's sparrow name Sphyrapicus spp. Picoides pubescens Tachycineta thalassina Empidonax difficilis Parus gambeli atricapillus Certhia americana Troglodytes aedon Turdus migratorius Myadestes townsendii Catharus spp. Regulus satrapa Vireo solitarius Dendroica coronata Q. petechia Coccothraustes vespertinus Passer domesticus Carduelis pinus pipno chlorurus Pooecetes gramineus Melospiza melodia Amphispiza bilineata Junco hyemalis Zonotrichia leucophrys Melospiza lincolnii z. lConifer habitat only. 2Aspen habitat only. LITERATURE Altmann, J. 1974. Observational Behavior 49:227-267. CITED study of behavior: sampling methods. Bloom, P. H. 1987. Capturing and handling raptors. Pages 99-123 in B. A. G. Pendleton, B. A. Millsap, K. W. Cline, and D. M. Bird, eds. Raptor management techniques manual. Natl. Wildl. Fed., Washington, D.C. 420 pp. Cottam, G., J. T. Curtis, and B. W. Hale. 1953. Some sampling characteristics of a population of randomly dispersed individuals. Ecology 34:741-757. Fischer, D. L., and J. R. Murphy. 1987. Foraging and nesting habitat Accipiter hawks in Utah. Brigham Young Univ. Unpubl. ms. of �218 Kenward, R. E. 1985. Raptor radio tracking I. Newton, and R. D. Chancellor, eds. Paston Press, Norwich, England. and telemetry. Pages 409-420 in Conservation studies on raptors. Moore, K. R., and C. J. Henny. 1983. Nest site characteristics of three coexisting accipiter hawks in northeastern Oregon. Raptor Res. 17:65-76. Mueller, H. C., D. D. Berger, and G. Allez. 1979. Age and sex differences size of sharp-shinned hawks. Bird Band. 50:34-44. in Reynolds, R. T. 1983. Management of western coniferous forest habitat for nesting accipiter hawks. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. RM-107. 7 pp. ________ . and E. C. Meslow. 1984. Partitioning of food and niche characteristics of coexisting Accipiter during breeding. Auk 101:761779. ________ , and H. M. Wight. 1982. Nesting habitat of coexisting accipiter hawks breeding in Oregon. J. Wi1dl. Manage. 46:124-138. Shuster, W. C. 1976. Northern West. Birds 7:108-110. goshawk nesting densities Storer, R. w. 1966. Sexual dimorphism and food habits American accipiters. Auk 83:423-436. Weber, W. A. 1976. CO. 479 pp. Rocky mountain flora. Winer, B. J. 1971. Statistical principles Hill Book Co., New York, NY. 907 pp. in montane Colorado. in three North Colo. Assoc. Univ. Press, Boulder, in experimental design. McGraw- 1 �219 Appendix A. Sharp-shinned hawk activity monitoring schedule for the 1989 field season. Sampling constraints used to develop the schedule: 1. 3 antennas, receivers, and towers (T) -- when 2T are used at 1 nest site, only 1T may be used at the following nest site because time periods overlap. 2. 3 field assistants (FA) -- the 3rd FA will monitor prey deliveries at nests where lT is used. 3. 5 nests (N), 1 breeding pair at each nest (MF). Activity N #T Sex N #T Sex N #T Sex N #T Sex N #T Sex 6-7 7-10 10-11 Hike/set-up Radio-monitor Prey remains 1 2T MF 2 2T MF 3 2T MF 4 2T MF 5 2T MF 9-10 10-13 13-14 Hike/set-up Radio-monitor Prey remains 2 1T MR 3 1T MR 5 lT F 1 lT 12-13 13-16 16-17 Hike/set-up Radio-monitor Prey remains 3 2T MF 4 2T MF 5 2T MF 15-16 16-19 19-20 Hike/set-up Radio-monitor Prey remains 4 lT MR 5 lT MR 1 1T F 2 1T F 17-18 19-21 20-21 Hike/set-up Radio-monitor Prey remains 5 2T MF 1 1T MR 2 2T MF 3 lT F Time r 4 lT F 1 2T MF 2 2T MF 3 1T Prepared by _yL"'_'.;;_<v.""¥~' t_"-U--( __ !.....;.1A~_~-,.'H,'-+/ _ Suzan~M. Joy ~ Graduate Research Assistant pR 4 2T MF Rrhe 1st sex monitored during each pair of 1T visits to nests will be randomly selected. I} pR ��221 Colorado Division of Wildlife Wildlife Research Report April 1989 JOB PROGRESS REPORT State of: Colorado Project: W-152-R Upland Bird Research Work Plan: 21 Job Title: Evaluation of Habitat Quality Eastern Colorado Period Covered: Author: Job 01 January 5__ on Conservation through 31 December Reserve Lands in 1988 Warren D. Snyder Personnel: T. Abell, C. Braun, D. Johnson, of Wildlife and W. Snyder, Colorado Division ABSTRACT Vegetation sampling to monitor habitat quality within 104 Conservation Reserve (CR) fields was initiated in early spring 1988 as part of a regional and national evaluation effort. Qf 104 sampled fields, 1 was seeded in 1986, 42 were seeded in 1987, 57 were seeded in 1988, and 4 remained to be seeded following establishment of satisfactory cover crops. Visual obstruction readings (VOR) during early spring (pre-greenup) had an average index of 0.39 dm, however, the VOR index in late June (nesting) was lower (0.20 dm). Planting 22 fields to grass and application of herbicides to numerous fields were primarily responsible for the lower June index. Vegetation canopy cover averaged 27% during early spring and 24% in late spring with annual forbs dominating. Average late June height was 9.7 cm. Rangeland and CR fields bordered 62% of the sampled CR field edges, thus, interspersion of covers was not enhanced in a majority of samples. The quantity, quality, and security (for nesting wildlife) of croplands associated with CR were monitored from early to late spring. Small grain stubble was nearly equal in quality to CR vegetation in early spring but much less secure. '.Green wheat attained VQR readings much greater than those within CR t.rac t stby early May .. Approximately 44% of the CR contracted during the 1st 4 signup interv-~ls'was outside . pheasant (Phasianus colchicus) range in eastern Colorado, whereas the remainder was within remnant (33%), low (17%), fair (2.5%), and moderate to good pheasant range (4%). Approximately 6% of the CR in eastern Colorado was within the range of northern bobwhite (Colinus virginianus) and about 16% lay within the range of scaled quail (Callipepla squamata). Mapping of CR distribution in relation to census routes continued. A general assessment of the values of the CR fields for several wildlife species was made. ��223 EVALUATION OF HABITAT QUALITY ON CONSERVATION RESERVE LANDS IN EASTERN COLORADO Warren D. Snyder INTRODUCTION The Colorado Division of Wildlife (CDOW) was represented at a meeting in Lubbock, Texas in February 1988, where personnel of the U.S. Fish and Wildlife Service's National Ecology Center (NEC) coordinated a regional meeting of state delegates. The purpose of the meeting was to; standardize data collection procedures among states, select representative species as a basis for evaluation, and provide a data base for use as part of a nationwide evaluation (by NEC) of the impacts of the Conservation Reserve Program (CRP) on wildlife. Subsequent to the meeting, NEC personnel provided each state representative with a randomized list of CR contracts stratified to sample fields retired from representative crop bases (wheat, corn, sorghum, etc.). In Colorado, the sample was restricted to the eastern "High Plains". Therefore, efforts by myself to obtain a stratified random sample of CR fields were cancelled. Three wildlife species, ring-necked pheasants, western meadowlarks (Sturnella neglecta), and cottontails (Sylvilagus spp.) were selected as the primary indicator species to monitor impacts of the CRP on wildlife within the Southern Great Plains Region in which Colorado was included. P. N. OBJECTIVES Determine the distribution and quantity of Conservation Reserve land in eastern Colorado in relation to the distribution of selected wildlife species, evaluate the quality of the vegetation on these lands for selected wildlife species, measure the response of selected wildlife species to the Conservation Reserve Program using existing annual surveys, and evaluate the impact of the Colorado Division of Wildlife's cost share program on cover quality. SEGMENT OBJECTIVES 1. Conduct evaluations of randomly selected CR tracts within eastern Colorado as part of a regional and national assessment of the Conservation Reserve Program being coordinated by the National Ecology Center (NEC) of the U.S. Fish and Wildlife Service. 2. Conduct intensive visual obstruction readings (VOR) from a stratified random sample of CRP fields and proximal controls. 3. Conduct intensive visual obstruction readings (VOR) from a sample of tracts cost-shared by the CDOW (for enhancement of cover quality) for comparison with CRP tracts not cost-shared. 4. Conduct pre- and post-treatment assessments of a randomly selected sample of CR fields based on Pat Rec and HSI models for a selected sample of wildlife species. �224 5. Determine the response of selected wildlife Reserve based on existing annual population 6. Compare the distribution wildlife species. 7. Compile Center, and analyze and prepare species to the Conservation surveys. of CRP in eastern Colorado data, submit necessary progress reports. to that of selected forms to the National Ecology METHODS The contract data base provided by the NEC was used during contacts of county offices of the Agricultural Stabilization and Conservation Service (ASCS) to obtain photocopies of CR contracts, aerial photos of fields, legal descriptions, and cropping history for a random sample of fields. An authorization letter form the State ASCS Director was obtained to facilitate release of data from county ASCS offices. Landowners and/or operators within 18 eastern Colorado counties representing 78 contracts and 104 CR fields were contacted to gain permission for access to fields and explain the purpose of the study. Pre-greenup vegetative sampling began in late March and extended into early April 1988. Data were recorded on a standardized data collection form provided by the NEC (APPENDIX A). The visual obstruction reading (VOR) Robel et. al (1969) was used to measure nesting cover quality obtained from CR fields during pre-greenup and late spring (mid to late Jun) nesting intervals (Table 1). The NEC requested 8 VOR samples per field however, 20 samples per field were obtained in Colorado to reduce within-field variability. Sampling was conducted on an accessible side of each field and extended into the field based on random selection of target objects (if available). The 1st sample was obtained 25 paces from the field edge and subsequent samples were obtained at 10 pace intervals thereafter. This VOR or height-density index (HDI) sampling technique has been used extensively in eastern Colorado (Snyder 1984Q, 1985, 1987, 1988) for herbaceous vegetation. The VOR index is based on procedures developed by L. M. Kirsch (unpubl. rep., U.S. Fish and Wildl. Serv., Jamestown, N.D., 1977). The NEC required a different (higher) interpretive reading of VOR for use in regional evaluations than the Kirsch method previously used in Colorado. To maintain continuity in Colorado sampling, the Kirsch method was retained as the basic method and an adjustment was made to correct it to the NEC method. Both VOR interpretations are listed for pre-greenup and nesting interval samples (Table 1). The Kirsch method is used in subsequent comparisons and discussions. The percent canopy cover of herbaceous vegetation within a 0.5 x 1.0 m (0.5 m2) Daubenmire frame was estimated twice at each of the 4 locations used in sighting toward the Robel pole. The 0.5 m2 plot lying immediately to the front and right of the sighting stick was sampled and the sample frame was flipped forward to obtain a 2nd sample. The 1st 8 samples were obtained at the 25 pace location and a 2nd group were tallied at the last location along the VOR sample transect. Perennial and annual grasses were distinguished from annual and perennial forbs. �225 Table 1. Visual obstruction readings (VOR, dm) among conservation reserve fields during pre-greenup and nesting intervals, eastern Colorado, 1988. N Sample fields Seeded in 1986 Seeded in 1987 Seeded in 1988 Before pre-greenup After pre-greenup Not seeded Overall mean Pre-~reenu~ VOR NECa Kirschb 1 42 57 35 22 4 104 Nestin~ NEC 0.00 0.46 0.38 0.09 0.84 0.01 0.65 0.39 VOR Kirsch 0.48 0.30 0.14 0.01 0.41 0.20 • aVOR required for use by the National bVOR developed by L. M. Kirsch. Ecology Center. A standard form provided by the NEC was used for data collection during the nesting interval (APPENDIX B). Procedures generally followed those used during the pre-greenup sampling interval. Nesting interval sampling was from mid to late June progressing from south to north across eastern Colorado. Sampling was conducted from early spring through early summer 1988 to provide data on quantity, quality, and security (for nesting wildlife) of land use types, including CR in eastern Colorado. Sampling through spring was nonrandom and restricted by time constraints, primarily to the eastern tier of counties. Pastures and rangelands were not included within spring samples but were included in the June samples. During mid- to late June sampling, roadside listings of cover types were obtained to 20 km from each sampled CR field during travel from one field to the next. Since CR fields were randomly selected, this provided a random distribution of associated cover types. RESULTS AND DISCUSSION Evaluation of Conservation Reserve Vegetation Quality Of the 104 fields sampled, 1 had been seeded in spring 1986, 42 fields were seeded in 1987, 57 were planted from winter through late spring 1988, and 4 remained unplanted awaiting establishment of an adequate cover crop prior to seeding grass. Of the 57 fields seeded in 1988, 35 (61%) had been planted prior to pre-greenup sampling whereas 22 (39%) had not yet been seeded and still retained a sorghum cover crop. The average VOR index among 104 pre-greenup 1988 field samples was 0.39 dm (Table 1). A ranking, based on experience in past studies (Snyder 1984Q, 1988) rated 73.1% of the fields as extremely poor « 0.26 dm), 9.6% as poor (0.26-0.50 dm), 6.7% as fair (0.51-1.0 dm), 4.8% as moderate (1.1-2.0 dm), and 5.8% as good (> 2.0 dm) nesting cover for pheasants during the pre-greenup �226 interval (Table 2). Some fields with high VOR indices had previously been seeded to grass but stands of residual annual forbs provided the primary cover. Most high VOR's were derived from 22 fields that retained a standing sorghum cover crop into which grasses had not yet been seeded (Table 1). Perennial grasses did not yield high VOR's within any field. Most grass stands, where present, were not yet developed and offered minimal cover. Table 2. Ranking of Conservation Reserve fields for nesting pheasants by VOR classification (Kirsch, dm) during pre-greenup and nesting intervals, eastern Colorado, 1988. Sample Pre-greenup Seeded in 1986-87 Seeded in 1988 Prior to sampling After sampling Not yet seeded Totals Nesting Seeded in 1986-87 Seeded in 1988 Not yet seeded Totals < N Fields 0.51-1.0 0.26 0.26-0.50 30 42 32 10 4 5 5 3 2 4 3 76 29 54 1.1-2.0 2.0 Totals 2 3 2 4 3 3 4 43 57 35 22 4 10 7 5 6 8 3 2 1 o 1 > 43 57 4 87 104 4 8 4 3 2 104 The average VOR index for the 104 fields previously sampled declined to 0.20 dm during the nesting interval. Of the fields sampled, 83.7% were rated extremely poor, 7.7% poor, 3.8% fair, 2.9% moderate, and 1.9% good (Table 2). The primary reason for the decline was that grasses were seeded between sample intervals into 22 fields that previously had contained standing cover crops (Table 1). This operation destroyed most standing residual lowering VOR indices. Chlorsulfuron (Glean) and other herbicides were applied to at least 31 fields (the total number treated is unknown) either in 1987 or 1988. Chlorsulfuron was effective in preventing growth of annual forbs on many fields leaving them almost void of green vegetation at time of nest-interval sampling. At least 20 fields, and probably more, had been mowed in 1987. Among the few sampled CR fields that possessed high VOR indices most were within stratum 3 and 4 in southeastern Colorado and contained either tall unmowed weeds or a standing cover crop (Fig. 1). These fields increased the average pre-greenup VOR's to 0.86 dm (stratum 3) and 0.66 dm (stratum 4). In contrast, VOR's in the other 4 strata were below 0.25 dm during pre-greenup. By the nesting interval, VOR's in strata 3 and 4 had declined to 0.28 and 0.07 dm respectively. Fields in northeastern Colorado possessed the highest VOR indices (0.33 dm in stratum 1, Fig. 1). However, comparisons by stratum will not be meaningful until perennial covers have developed. Vegetation canopy cover varied widely among fields and treatments, but averaged 27.4% for the early spring sample and 24.0% for mid to late June. Within the latter sample, 22.1% was attributed to grasses (both annual and 4 �227 WEt. 1 0 I l. A SAN I MAS i d·····_ .. ....~._ :V._, . ~~ ~. .•..__;.l..•..__ ..l~ Fig. 1. Stratification for random sampling conservation eastern Colorado, 1988. _ reserve fields in �228 perennial) whereas 77.9% was attributed to forbs, primarily annuals. Average height of vegetation in the 104 fields in late June was 9.68 em (3.8 in.). Annual precipitation in 1987 was above average at 7 of 9 locations distributed in eastern Colorado (Table 3). In contrast, only 1 of these (Springfield) recorded above average precipitation in 1988. However, precipitation was not markedly deficient during 1988 in eastern Colorado. Only a trace of moisture was received in November-December 1988 (actual data not available) and the data (Table 3) represent the actual amounts received for most locations. Precipitation was deficient in April but above average in May and June at most locations both years. However, June 1988 was extremely warm and dry in northeastern Colorado. July rainfall averaged slightly below normal during both years. Above average rainfall in May during both years was probably the most important factor promoting grass establishment on CR fields. Precipitation was not markedly different than would be expected in eastern Colorado and fair grass establishment was observed in numerous fields. Establishment of perennial grasses is increasingly difficult from north to south in eastern Colorado and above average precipitation in both 1987 and 1988 in Baca County undoubtedly aided grass establishment there. Table 3. Annual eastern Colorado, precipitationa 1987-88. Location average Quality, and Security locations in 1988 16.65 15.40 12.50 15.09 17.41 17.34 12.45 17.61 14.96 21.84 15.10 11.51 19.84 18.22 19.85 15.00 20.06 14.92 16.88 11.21 9.05 13.53 12.21 15.74 10.93 16.22 14.36 15.49 17.37 13.35 ~ aNovember and December amounts are missing amounts were extremely small. Quantity, Bureau 1987 Long-term Springfield Lamar Rocky Ford Limon Burlington Akron Greeley Holyoke Sterling Combined (in.) at 9 U.S. Weather for 1988 but in general of Land Use Types Percentages of major crop types available to wildlife within portions of several counties or groups of counties varied (Table 4). There was an inverse relationship between fallow/mulched stubble and standing small grain stubble with a much greater percentage of fallow/mulch in southern counties and greater proportions of standing stubble in northeastern Colorado (Table 4). Mid-April sampling was not conducted in southern Prowers and Baca counties (extreme southeastern Colorado). Observations indicated most wheat stubble in these areas had been cultivated in fall 1987. Thus, percentages should be similar to those for northern Prowers and Kiowa counties. Observations in previous years indicated that most wheat stubble in southeastern Colorado was �229 tilled in late summer after harvest whereas most was left standing overwinter in northeastern Colorado. The combination of fallow/mulch and standing small grain stubble was the dominant cover type representing 46% of the total cropland sampled. Green wheat comprised 37% of the mid-April cropland and exceeded 30% in all but one sample. Conservation Reserve acreage ranged from o to 23.1% within the sample groups, decreasing from south to north. Millet stubble averaged < 5% of the available cropland whereas the percent of dryland and irrigated rowcrops (corn, sorghum, sunflowers) varied widely among counties (Table 4). Table 4. & Cropland cover types (X) in eastern Colorado, mid-Apri l 1988. County/location fields !!. Fallow/ mulch Wheat stubble Green wheat Conservation Reserve Mi llet stubble Row crop N.Prowers-Kiowa Cheyenne Kit Carson S. Yuma Phillips/Sedgwick Phillips/Logan Logan/lJashington SIILogan/Morgan 143 169 161 99 367 250 312 168 30.8 20.1 39.1 29.3 13.6 12.4 25.0 22.0 4.9 23.1 6.8 12.1 33.0 30.8 36.5 26.2 33.6 40.2 37.3 37.4 40.3 38.4 21.8 44.0 23.1 14.2 2.5 2.0 0 3.2 4.2 3.0 4.2 2.4 0 0 1.9 5.6 8.3 4.2 3.5 0 14.3 19.2 11.2 7.2 4.2 0.6 The VOR indices among 7 standing wheat stubble fields sampled in early spring ranged between 0.28 and 0.51 dm and averaged 0.40 dm. This was similar to the 0.39 dm measured in CR fields. Sampling of standing wheat stubble in southeastern Colorado was inadequate to provide meaningful data but general observations indicated VOR's there would have been lower. The VOR's within 6 mulched stubble fields ranged from 0.05 to 0.30 dm and averaged 0.17 dm, much below standing stubble and extremely marginal for pheasant nesting. Based on past experience (Snyder 1984Q, 1988), standing stubble fields, examined during mid-April, were arbitrarily rated as to their nesting quality for pheasants (Table 5). Most were rated fair except in parts of southeastern Colorado where fields rated poor dominated the sample. Wheat stubble was the only vegetation type, other than CR, providing suitable residual nesting cover in early spring. Standing small grain stubble (primarily winter wheat) was not secure nesting cover and nearly all was lost to tillage during the spring nesting season. Tillage progression varied among localities, but a survey conducted along a previously established Holyoke-Fleming route (Snyder 1988) provided a general index for northeastern Colorado (Fig. 2). Progression of tillage advanced in 1988 at about an average rate when compared to data from previous years (Snyder 1988). Wheat stubble was much more abundant than CR in northeastern Colorado and about equal in nesting quality during spring 1988. However, due to tillage disturbance, it was much less secure. Mulched stubble, while common in southeastern Colorado, was much lower in quality and security. Where tall annual forbs or sorghum existed within CR fields over winter in pheasant range in southeastern Colorado, CR provided valuable winter habitat for pheasants and cottontails. �230 Table 5. Ranking (%) of wheat stubble quality for pheasant nesting in eastern Colorado, spring 1988. County/location N Poor Fair Good N. Prowers-Kiowa Cheyenne Kit Carson S. Yuma Phillips-Sedgwick Phillips-Logan S. Logan-N. Wash. SW Logan-Morgan 7 39 11 12 121 77 114 44 57.1 12.2 45.4 0 10.7 19.5 30.7 9.1 28.6 7l.8 54.6 83.3 71.9 68.8 6l.4 54.5 14.3 15.4 0 16.7 17.4 15.1 65'.9 19.0 ~ 11.7 7.9 36.4 100 90 FALLOW & MULCH 80 I70 I- ~ ... Vl a '- 60 I- ...J "- UJ u:: "- 50 -, -, '- '- 40 " \ \ 30 I- STANDINS STU8BLE \ " \ \ 20 I- " \ \ 10 I- ECOFALLOW 0 19 APR 28 11 26 MAY Fig. 2. Status and conversion of small grain stubble fields to fallow, Holyoke - Fleming route, northeastern Colorado, 1988. Q �231 A 2nd extensive roadside sample of crop type occurrence was conducted on 9 and 10 May 1988 primarily in southeastern Colorado extending into Baca County (Table 6). Spring tillage of stubble fields had been in progress prior to this survey and fallow/mulched fields dominated along with green wheat. By this sample interval, green wheat and other small grains had attained considerable growth and were the dominant nesting cover along with CR fields. Green wheat did not attain significant growth in northeastern Colorado prior to 15 April 1988. Progression of growth had advanced beyond the average for CR fields by late April and was 3.7 dm by late May within northeastern Colorado fields (Fig. 3). Samples in Baca and Prowers Counties on 9-10 May showed wheat growth was more advanced there than in northeastern Colorado and a hypothetical growth curve for that area is illustrated (Fig. 3). Sampling (VOR) of maturing wheat fields in late June showed those in northeastern Colorado averaged> 6 dm compared to 4.7 dm among several fields in southeastern Colorado. Table 6. Cropland cover types County/location (%) !i fields N.Prowers-Kiowa Cheyenne Kit Carson S. Yuma in several eastern Colorado counties, 9-10 May 1988. Fallow/ f1J.Jlch 41.2 28.3 43.3 46.2 119 177 141 78 Wheat stubble Green wheat Conservation Reserve Mi llet stubble 2.5 14.7 1.4 7.7 33.6 42.4 39.7 34.6 19.3 13.0 2.1 0 3.4 1.1 1.4 5.1 Row crop 2.7 0.6 12.1 6.4 4 I 3.5 I I I I 3 I / / 2.5 5 \.J a: GREEN wrEAT - SE •..••. / / / I 2 I ~ I I 1.5 I I GREEN WHEAT - NE I I 1 I CR 0.5 ...........;.:.-.; . ~ o 1S APR 21 28 5 11 26 MAY Fig. 3. Progression of wheat growth based on visual obstruction indices (dm) in southeastern and northeastern Colorado in relation to that of 104 conservation reserve fields, 1988. �232 Canopy cover of wheat fields averaged 58.6% in late June in northeastern Colorado and 44.6% in southeastern Colorado. Canopy cover within sampled CR tracts was 24% in late June. Wheat height was 68 cm in northeastern Colorado and 59 cm in southeastern Colorado in contrast to an average vegetative height of 9.7 cm within CR fields. Green wheat was marginally secure as nesting cover for pheasants in 1988. Hot, dry weather in June advanced maturity and harvest began around 25 June whereas the average harvest initiation date is after 4 July in northeastern Colorado. Pheasant brood counts conducted by cnow personnel during August 1988 revealed extremely poor pheasant reproduction potentially attributed to hot dry weather and the early harvest in combination (Snyder 198412.). More extensive sampling of vegetation and cover types distributed over eastern Colorado was obtained during the mid- to late June 1988 CR nesting cover sample interval. Pasture and rangeland was included within the inventory (4,170 samples). Since millet was still being planted, an accurate assessment of its occurrence could not be made. Thus, percent fallow may be slightly inflated. However, I believe the percentages within county groups are representative (Table 7). Percent rangeland and CR increased in southern areas of the State. Exclusion of rangeland provided more meaningful comparisons of crop types and CR showing the dramatically greater amount of CR in southern parts of eastern Colorado (Table 8). Percentages of cover types bordering the 104 sampled CR fields provided an additional index of proportional occurrence of cover types (Table 9). However, since CR fields are more abundant in marginal farmland, percent occurrence of rangeland is possibly inflated. Table 7. Major vegetation types (%) among grouped county locations in eastern Colorado, June 1988. Vegetation NEa NWb ECc SWd SEe Rangeland Fallow Small grains Conservation Reserve Row crops & millet Alfalfa Other 20.0 32.2 30.0 1.6 13.1 0.1 3.0 17.3 37.9 37.7 2.3 2.7 0 2.1 22.4 38.4 27.0 6.4 4.9 0.3 0.6 53.2 18.7 9.0 9.5 2.3 0.5 6.7 38.2 21.2 13.9 16.3 6.0 4.4 0 aLogan, Phillips, Sedgwick, and Yuma counties. bArapahoe and Weld counties. CCheyenne, Kit Carson, and Washington counties. dElbert, El Paso, Lincoln, and Pueblo counties. eBaca, Bent, Kiowa, and Prowers counties. 31.2 28.2 21.7 9.1 6.2 1.8 1.8 �233 Table 8. D Major crop types (X) within grouped county locations in eastern Colorado, June, 1988. Vegetation NEa NWb ECc SWd SEe Fallow Small grain Conservation Reserve Sorghum/millet Corn Beans/beets Alfalfa Other 40.2 37.5 2.0 0.3 15.7 0.3 0.2 3.8 45.8 45.6 2.8 0.6 1.3 1.3 0 2.6 49.5 34.8 8.3 2.2 3.5 0.6 0.4 0.7 40.0 19.2 20.4 2.7 0 2.3 1.2 14.2 34.5 22.4 26.4 6.9 2.7 0 7.1 0 40.9 31.6 13.2 3.2 5.3 0.6 2.6 2.7 aLogan, Phillips, Sedgwick, and Yuma counties. bArapahoe and Weld counties. CCheyenne, Kit Carson, and Washington counties. dElbert, El Paso, Lincoln, and Pueblo counties. eSaca, Bent, Kiowa, and Prowers counties. In addition to providing secure nesting cover, CR fields should increase edge and interspersion of cover types which many wildlife species require for feeding, brood rearing, etc .. However, 33.4% of the CR field borders were adjacent to rangeland or pasture and another 28.8% were adjacent to other CR fields (Table 9). This grouping, represented 62.2% of the total edge and indicated that diversity was not greatly enhanced. Residual stubble, fallow, and small grains bordered 32.0% of the sampled CR tract edges and sorghum and corn bordered an additional 3.6%. Developed land (building sites, etc.) and other (mostly minor crops) represented 2.2% (Table 9). Based on general observations and assessments, approximately 32% of the 104 fields increased diversity by extending grass into cropland, whereas 38% decreased diversity by converting former cropland within rangeland into grass. About 30% of the CR tracts did not markedly change diversity. Approximately 22% of the sampled CR tracts extended rangeland into cropland, 24% reduced cropland in a range dominated site, 9% eliminated cropland in a range dominated site, and an additional 45% provided no change. Percent rangeland varied widely among strata from 24% within stratum 1 to 57% in stratum 4 (Table 9). Adjacent CR was highest in strata 3 and 5. Highest associations with stubble and fallow were in the northern part of eastern Colorado whereas the highest association with small grains was within the eastcentral (stratum 2) part of the state. Conservation Reserve fields, primarily within the eastern tier of southeastern Colorado counties, were evaluated during a nonrandom inspection on 18-19 July 1988. The 162 CR fields were subjectively rated as containing none, low, medium, or high quality cover for pheasant broods. Cover conditions were rated low within 94 (58.0%) of the fields, whereas 19.8% were rated medium, and 1.9% were rated high (Table 10). One-fifth (20.4%) contained no significant brood cover primarily because they had been treated with herbicides earlier in the year. Most, but not all, were within historic pheasant range. �234 Table 9. Cover type associations (X) with Conservation Reserve based on percent of edge (104 fields sampled within 6 strata), eastern Colorado, 1988. Cover type Rangeland Cons. Reserve Stubble/fallow Small grains Corn Sorghum Othera Developedb 23.8 15.0 30.2 16.1 7.8 1.9 4.3 0.9 2 3 Stratum 4 5 6 ~ 25.2 16.2 21.6 28.0 7.8 0.5 0.2 0.5 22.2 39.0 20.5 13.9 0.6 2.5 0.8 0.5 57.3 21.2 14.0 6.3 0 0.9 0 0.3 37.9 38.7 9.8 7.6 0.7 2.0 2.4 1.0 31.0 16.2 32.2 19.6 0 0 0.2 0.9 33.4 28.8 19.0 13.0 2.0 1.6 1.5 0.7 aprimarily alfalfa, trees, and other minor crops. bprimarily farmyards. Table 10. Rating of Conservation Reserve southeastern Colorado, 18-19 July 1988. High Value Medium Kiowa Eastern Western 0.0 0.0 7.1 16.7 Prowers 0.0 Baca Two Buttes Other fields for pheasant (% of total) Low brood habitat, N None fields 78.6 58.3 14.3 25.0 14 24 26.7 43.3 30.0 30 0.0 5.3 17.9 21.1 67.8 55.3 14.3 18.4 28 38 Bent 0.0 0.0 66.7 33.3 3 Cheyenne 4.0 24.0 56.0 16.0 25 1.9(3)a 19.8(32)a 58.0(94)a 20.4(33)a 162 County All fields "Tocal, fields. Conservation Reserve Association with Wildlife Distribution Conservation Reserve acreage distribution within eastern Colorado, based on data through the 1st 4 CR signups, was compared with the distribution and general density classifications for ring-necked pheasants, northern bobwhite, and scaled quail. Data were contrasted to pheasant range based on 1982-83 distribution-density estimates (Snyder 1985). Analysis indicated 43.8% of the �235 CR in eastern Colorado was outside pheasant range, whereas 32.6% occurred within range classed as remnant, or it contained only scattered occurrences of the species. About 16.9% of the CR was within range classed as low, 2.5% was within fair range, and 4.2% was within moderate to good pheasant range. Since remnant range in eastern Colorado provides almost no hunting opportunity, only 23.6% of the CR acreage occurred within huntable range. Most pheasant range rated moderate to high in 1982-83 has deteriorated to low to fair status in recent years. A higher proportion of land recently committed to CR within signups 5 through 7 is within pheasant range classed as low to good. However, the amount of land committed to the CRP during recent signups was much less than that during the 1st 4 signups. These data illustrate that much of eastern Colorado is extremely marginal for both farming and pheasants limiting the value of CR for the species. Since pheasants are primarily found within the better farmlands and CR was more extensively committed to marginal farmland, an inverse relationship between pheasant abundance and CR was noted. One exception was in portions of Baca County where extensive conversion to CR occurred within what is presently Colorado's best pheasant range. Comparison of CR distribution with that of northern bobwhite was based on bobwhite distribution presented in Snyder (1984~). Only 6% of the CR acreage was within northern bobwhite range, primarily remnant or marginal habitats. The best bobwhite range is along riparian streamside habitats in Colorado and, therefore, is separated from CR, especially along the South Platte River. Scaled quail distribution and density were based on Hoffman (1965) and modified to exclude range he classed as very poor, since most of this was farmland or shrub less shortgrass unsuited for quail habitation. Hoffman rated a large proportion of the scaled quail range as good based on habitat characteristics rather than population densities existing there. As a consequence, 2.2% of CR acreage was within poor scaled quail range, 7.4% was within fair range, 5.5% was within good range, and 1.0% was within range classed as very good or excellent. Thus, 16.2% of the CR was within or closely associated with scaled quail range. This analysis used townships as the basic unit of measure and scaled quail range was often isolated along rangeland-dominated drainages distributed as fingers of habitat within sections and townships. If a more refined analysis was conducted, the percentage of CR acreage within actual scaled quail range would be much smaller. If southeastern Colorado scaled quail range was reclassified based on long-term densities, a vast majority would be rated poor or low rather than good range. Quotas (-25% of total cropland) of CR were attained in most southeastern Colorado counties during the 1st 4 signups. Thus, no significant change in the CR-scaled quail range relationship is anticipated. Percentages of the 104 sampled CR fields within the ranges of 7 eastern Colorado game species were recorded during June 1988 (Table 11). Only 4 fields (3.8%) were within the range of prairie grouse (Tetraoninae), whereas 40.4% were within the range of Pronghorn (Antilocapra americana) and all fields were within the range of mourning doves (Zenaida macroura) and nongame passerines. When the CR field was within the range of a wildlife species, the overall habitat quality of the tract was rated (poor, fair, good, excellent) for that species (Table 11). For most game species, the habitat quality rating was in the poor classification although the fair classification dominated for pronghorn. Only a few fields were rated good and none were rated excellent. �236 Table 11. Occurrence of selected wildlife in association with 104 Conservation Reserve fields and the quality rating of these fields to wildlife, eastern Colorado, June 1988. Occurrence Species/group x Poor Ring-necked pheasant Northern bobwhite Scaled quail Prairie grouse Cottontail Pronghorn Mourning dove Nongame passerines 63.5 11.5 19.2 3.8 66.3 40.4 100.0 100.0 72.7 83.0 85.0 75.0 81.2 35.7 67.0 76.9 Rating of habitat gual it~ Fair Good 22.7 17.0 15.0 25.0 18.8 61.9 31.1 21.2 Excellent 4.5 0 0 0 0 2.4 1.9 1.9 0 0 0 0 0 0 0 0 An attempt was also made to rank the 104 fields as to their relative importance to selected wildlife species (or species groups). Most fields were rated of highest value to nongame passerines with some fields having value for pronghorn and mourning doves (Table 12). These ratings were subjective and based on June 1988 conditions within and surrounding the fields. These ratings would undoubtedly change during subsequent inspections. Table 12. Relative importance of 104 Conservation Reserve fields to selected wildlife, eastern Colorado, June 1988. lJildlife R-n pheasant Northern bobwhite Scaled quail Prairie grouse Cottontail Pronghorn Mourning dove Nongame passerines 2 2 0 1 0 0 17 4 80 17 0 0 0 6 11 41 22 Relative imQQrtance among s~ciesa 4 5 3 24 1 0 0 17 7 49 2 10 2 8 3 38 3 a a 11 5 10 1 7 3 2 a 6 7 8 2 3 1 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 a a 0 0 , aHighest value = 1, lowest value = 8 Progress on Other Phases of Study Preliminary work was begun on plotting CR (and other cover types) along pheasant crowing, mourning dove, and breeding bird survey census routes in eastern Colorado. However, extensive work continues and population changes of selected wildlife species in relation to CR distribution may not be detectable (if detectable) for several years. The Colorado Division of Wildlife cost shared to promote planting of perennial vegetation considered of greater value to wildlife on numerous fields, primarily within the eastern tier of counties. A random sample of these tracts was obtained with the assistance of Ernest Kaska and Tim Davis in late fall 1988. Sampling is to be initiation in 1989. However, additional time �237 may be needed to discern vegetation quality differences, development of perennial grasses is slow. if they exist, since Not all the variables sampled within the NEC data forms have been summarized and therefore are not included here. A summary of these data may be forthcoming from NEC personnel. LITERATURE CITED Hoffman, D. M. 1965. The scaled quail in Colorado - Range, population, status, and harvest. Colorado Dep. Game, Fish and Parks Tech. Bull. 18. 47pp. Robel, R. J., J. N. Briggs, A. D. Dayton, and L. C. Hulbert. 1970. Relationship between visual obstruction measurements and weight of grassland vegetation. J. Range Manage. 23:295-297. Snyder, W. D. Colorado. 1984~. Management procedures for northern bobwhites Colorado Div. Wildl. Spec. Rep. 56. 22pp. 1984g. High Plains. in eastern Ring-necked pheasant nesting ecology and wheat farming on the J. Wildl. Manage. 48:878-888. 1985. Management procedures for ring-necked Colorado Div. Wildl. Spec. Rep. 59. 53pp. pheasants in Colorado. 1987. Evaluation of sandsage-bluestem pra~r~e. Job Progress Rep., Colorado Div. Wildl., Wildl. Res. Rep., Fed. Aid Proj. W-152-R Apr. :331356. 1988. Evaluation of no-till wheat farming. Job Final Rep., Colorado Div. Wildl., Wildl. Res. Rep., Fed. Aid Proj. W-152-R. Apr. In press. Prepared by '%d~¥ Warren D. Snyder Wildlife Researcher C ��239 APPENDIX A PRE-GREENUP PERIOD DATA FORM Southern Great Plains Region l. Your Name: 2. County: 4. Contract 3. #: 5. State: Year to start: 6. CP#: ASCS Office 7. Owner/operator: 8. Field ID: 11. Contract Telephone 9. Field 2 CP# Acres 12a. Contracted planting forestry; wildlife, Description 13. Possible 10. Field acres: field descriptions: Field 1 CP# Acres 12b. Contracted Signup #: No.: (e.g., cool season/legume; or other): if "other," temporary pheasant Field 5 CP# Acres warm season grasses; or seed mix if CPl or CP2: cover crop or residue winter Description/location: Field 4 CP# Acres Field 3 CP# Acres (if any): cover on surroundings: Distance: �240 15. Directions for getting to the field: 16. Attach xerox copies of the contract, crop history form, and the ASCS photo of the field and surroundings. If the photo is not available, draw a sketch on the back of this form. Field sampling 21. Date of field work: 22. Location 23. Description (Starting of access point: of landmarks used. Show location on photo (14). landmark): (Target landmark): 24. Location of point 1 (# of steps): Starting point or notes: 25. Direction notes 26. Location Daubenmire Herb. canopy cover Robel reading Plot #1 Shrub canopy cover Daubenmire Herb. canopy cover Plot #2 Shrub canopy cover dm ---% --- % --- % % dm --- % --- % --- % --- % dm --- % --- % --- % --- dm ---% --- % --- % --- % of point 2 (# of steps): Notes: % �241 PRE - GREENUP DATA FORM Contract # 25. Direction notes Robel reading Whole field characteristics 31. Daubenrnire Plot #1 Herb. Shrub canopy canopy cover cover dm --- % dm --- % dm --- % dm --- % Daubenrnire Plot #2 Herb. Shrub canopy canopy cover cover ---% ---% ---% ---% --- % --- % --- % --- % --- % --- % ---% --- for this CP % of CP area undisturbed: amount (%) : mowed: amount (%) : grazed: amount (%) : burned: amount (%) : other: amount (%) : 100 TOTAL 32. % When was the permanent Is the permanent contracted contracted What are the dominant cover planted? cover present (year) on this CP? (Y/N): species?: 33. What is the quality class of winter cover for pheasant on the CP? (Poor: 0/10; Fair: 1-3/10; Good: 4-6/10; Excellent: 7-10/10): 34. Is there winter food for pheasants? a. On this CP? (Y/N): b. Close to this CP? (Y/N): « 1/4 mile-CO, cover for pheasants KS, NE, WY; < 1/2 mile-OK. 35. Is there winter within 2 miles of this CP? 37. Which of the following is the single most limiting life requisite pheasants within 2 miles, but not including the field? (N: nesting cover; WF: winter food; WC: winter cover): NM, TX) (Y/N) for �242 APPENDIX B NESTING PERIOD DATA FORM Southern Great Plains 1. Your Name: 2. County: 4. Contract 8. Field Field 3. #: 6. CP#: ID: Sampling 21. Date of field work: 22. Location 23. Description of access (Starting 24. State: point: of landmarks used. Show location on photo (14). landmark): (Target landmark): Location of point 1 (# of steps): Starting point or notes: 25a. Direction notes Robel reading 25b. Distance to meadowlark 26. of point Location Daubenmire Herb. canopy cover Plot #1 Shrub canopy cover Daubenmire Herb. canopy cover Plot #2 Shrub canopy cover dm --- % --- % --- % % dm --- % --- % --- % % dm --- % --- % --- % % dm --- % ---% --- % % perch site: 2 (# of steps): left side of line: right side of line: Notes: M M �243 27a. Robel reading Direction notes 27b. Distance Daubenmire Herb. canopy cover Daubenmire Herb. canopy cover -_% --- % ---% --- % dm ---% --- % -_% --- % dm --- % --- % --- % --- % dm -_% --- % --- % % perch site: Whole field characteristics for this CP left side of line: right side of line: M M % of CP area undisturbed: "amount mowed: amount (%): grazed: amount (%) : burned: amount (%) : other: amount (%) : (%) : TOTAL 32. Plot #2 Shrub canopy cover dm to meadowlark 31. Plot #1 Shrub canopy cover When was the permanent Is the permanent contracted contracted cover planted? 100 (year) cover present on this CP? (Y/N): What are the dominant species?: 36. What winter cover quality class will the present cover in this CP likely supply for pheasants next winter? (Poor: 0/10; Fair: 1-3/10; Good: 4-6/ 10; Excellent: 7-10/10) 37. Which of the following is the single most limiting life requisite pheasants within 2 miles, but not including the field? (N: nesting cover; WF: winter food; WC: winter cover): 38. Is there brood cover for pheasants? a. On this CP? b. Within (Y/N): 1/2 mile of this CP? (Y/N): for �244 NESTING DATA FORM 39. Contract # Number of cover type patches adjacent to the field: Ungrazed grassland Corn Range, native grass, shrubs Cotton Range, introduced grass Small grains Hayland, timber, orchards Sorghum Woodland, timber, orchards Wetland Fallow cropland, stubble, bare ground Open water Alfalfa and clover Developed land Beans �Colorado Division of Wildlife Wildlife Research Report April 1989 245 JOB PROGRESS State of: Colorado Project: W-152-R Upland Bird Research Work Plan: 22 Job Title: Avian Research Period Covered: Author: REPORT Job 01 January 1__ Publications through 31 December 1988 Clait E. Braun Personnel: C. E. Braun, K. M. Giesen, R. W. Hoffman, Snyder, Colorado Division of Wildlife T. E. Remington, W. D. ABSTRACT Progress was made on preparing and submitting manuscripts journals. Two manuscripts were published. Giesen, K. M. 1988. Status of lesser prairie-chickens Field-Ornith. 22:57-58. to technical in Colorado. Remington, T. E., and C. E. Braun. 1988. Carcass composition reserves of sage grouse during winter. Condor 90:15-19. Colo. and energy � https://cpw.cvlcollections.org/files/original/3d0701ffef240ca8cb52c149f7c4d644.pdf ae355eac0a2912a10e0c3d568477ef78 PDF Text Text 1 Colorado Division of Wildlife Wildlife Research Report July 1989 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~ Project No. W-153-R-3 Work Plan No. Job. No. Personnel: ~l~ 7 Period Covered: Authors: _ Mammals Research _ Multispecies Investigations Terrestrial Research Publication, Editing and Library Service July 1, 1988 - June 30, 1989 M. W. Hershcopf, L. H. Carpenter R. B. Gill, N. McEwen, L. Lovett, K. Chociej, all Mammals Researchers S. Eby, and ABSTRACT During the 1988-89 Segment, 16 books were purchased for permanent reference by DOW personnel. Fifty additional publications were located, ordered, and obtained free of charge for use. Fourteen of these were purchased, obtained on Interlibrary Loan, or given to the library. An additional 1,265 individual references requested by Mammals Researchers were located by library staff and made available for use. About 30 of these requests were not available locally and were obtained through interlibrary loans. Twelve manuscripts were published in various journals. ��3 MAMMALS PUBLICATION, EDITING AND LIBRARY SERVICES Marian W. Hershcopf and Len H. Carpenter P. N. OBJECTIVES To provide a centralized support program for manuscript editing services to facilitate publishing results of research conducted 01-03-047 - 11700 and 01-03-048 - 11700 and 16700. and library in projects SEGMENT OBJECTIVES 1. To provide coordinated and efficient editing and library services publish findings for all Colorado Mammals Research programs. and 2. To provide for the centralized support program for Mammals Research editing, library, and publishing services so that Mammals Research scientists can be most efficient in publishing results of their research. SUMMARY OF SERVICES Publications purchased with Mammals Research funds and placed in the Research Center Library Allred, M. 1986. Beaver behavior: architect of fame and bane. Naturegraph Publishers, Inc. Happy Camp, CA. 110pp. Brown, L., and J. F. Downhower. 1988. Analyses in behavioral ecology: a manual for lab and field. Sinauer Assoc., Inc., Sunderland, MA. 194pp. Eastern alack Bear Workshop on Research and Management. Proceedings 5th, 1980, Wrightsville Beach, NC, 292pp.; Proceedings 7th, 1984, Homosassa, FL, 85pp.; Proceedings 8th, 1986, Williamsburg, VA, 249pp. Hobbs, H. H., III, and J. P. Jass. The crayfishes and shrimp of Wisconsin. Milwaukee Public Museum, Milwaukee, WI. l77pp. Hunt, C. E. 1988. Down by the river: projects and policies on biological DC. 260pp. the impact of federal water diversity. Island Press, Washington, Huntley, A. C., et al., eds. 1987. Approaches energetics. Soc. Marine Mammal., Lawrence, Kurten, B., and E. Anderson. 1980. Pleistocene Columbia Univ. Press, New York, NY. 442pp. to marine mammal KS, Spec. Publ. No.1. mammals 253pp. of North America. �4 Novak, M., et a1., eds. 1987. Wild furbearer management and conservation in North America. Ontario Trappers Assoc. and Ontario Ministry of Natural Resources, Toronto, Ontario, Can. 1150pp. Putman, R. 1988. The natural history Press, Ithaca, NY. 191pp. of deer. Cornell University Renecker, L. A., ed. 1987. Focus on a new industry. Proceedings of the Alberta Game Growers' Association Conference, Red Deer, Alberta, Alberta Game Growers Assoc., Edmonton, Alberta, Can. ll0pp. Rolston, H., III. natural world. 1988. Environmental ethics: duties to and values Temple Univ. Press, Philadelphia, PA. 391pp. in the Soule' ,M. E., ed. 1987. Viable populations for conservation. Cambridge Univ. Press, New York, NY. 189pp. Starfield, A. M., and A. L. B1eloch. 1986. Building models for conservation and wildlife management. Macmillan Publishing Co., New York, NY. 253pp. Zeveloff, S. I. 1988. Mammals of the intermountain Utah Press, Salt Lake City, UT. 365pp. Publications obtained west. Univ. of free or at low cost In addition to books purchased with Federal Aid Funds, about 50 free reports and short publications from state or federal agencies or from private sources were located, ordered, and obtained for use by Mammals Research personnel. Theses purchased. obtained on Interlibrary Loan or as gifts for use by Researchers Methods and applications in estimating mortality Barlow, J. P. 1982(?). Ph.D. Diss., Univ. of California, San Diego, CA. other vital rates. 177pp. Collins, T. C. 1976. Population characteristics and habitat relationships of beavers, Castor canadensis, in northwest Wyoming. Diss., Univ. of Wyoming, Laramie, WY. 172pp. and Ph.D. Greer, S. Q. 1987. Home range, habitat use, and food habits of river otters in southwestern Montana. M.S. Thesis, Montana State Univ., Bozeman, MT. 9lpp. Griess, J. M. 1987. River otter reintroduction in Great Smoky Mountains National Park. M.S. Thesis, Univ. of Tennessee, Knoxville, 148pp. Harmoning, A. K. 1976. White-tailed deer dispersion and habitat utilization in central North Dakota. M.S. Thesis, North Dakota State Univ., Fargo, ND. 56pp. TN. �5 Hardesty, J. Y. (n.d.) Riparian vegetation at three sites along the Gila River in southwest New Mexico. M.S. Thesis, New Mexico State Univ., Las Cruces, NM. 101pp. Kafcas, E. N. 1987. Census and exploitation of a discrete beaver population in Michigan. M.S. Thesis, Central Michigan Univ., Mount Pleasant, MI. 88pp. Liewer, J. A. 1988. Pronghorn grazing impacts on winter wheat. M.S. Thesis, Colorado State Univ., Fort Collins, CO. 32pp. Marcum, C. L. 1975. Summer-fall habitat selection and use by a western Montana elk herd. Ph.D. Diss., Univ. of Montana, Missoula, MT. l88pp. Olson, W. W. 1975. Effects of controlled burning on grassland within the Tewaukon National Wildlife Refuge. M.S. Thesis, North Dakota State Univ., Fargo, ND. 137pp. Polechla, P. J., Jr. 1987. Status of the river otter (Lutra canadensis) population with special reference to reproductive biology. Ph.D. Diss., Univ. of Arkansas, Fayetteville, AR. 383pp. Robb, L. 1987. Gastropod intermediate hosts of lungworms (Nematoda: Protostrongy lidae) on a bighorn sheep winter range: aspects of transmission. M.S. Thesis, Univ. of Alberta, Edmonton, Alberta, Can. lllpp. Shelton, L. R., III. 1978. Values of big game to western slope ranchers of Colorado. Ph.D. Diss., Colorado State Univ., Fort Collins, CO. 17lpp. Silflow, R. M. 1989. Comparison of pulmonary host defense mechanisms in Rocky Mountain bighorn sheep (Ovis canadensis canadensis) and domestic sheep. M.S. Thesis, Washington State Univ., Pullman, WA. l08pp. Reference document location and delivery The Research Center Library staff also located and delivered about 1,265 individual articles on request for Mammals Researchers during this segment; about 30 were not available locally and were obtained through Interlibrary Loan procedures. Manuscripts published Job Progress Reports; Federal Aid. All studies. Anderson, A. E., and R. J. Tully. 1988. Status report, mountain lion, Colorado. Proceedings Third National Mountain Lion Workshop. Prescott, AZ. (in press). , D. C. Bowden, and D. M. Kattner. 1988. Dynamics of home range size of unhunted mountain lion (Felis concolor hippolestes) in southwestern Colorado. (Abstract). Proceedings Third National Mountain Lion Workshop, Prescott, AZ. (in press). �6 Anderson, A. E., D. C. Bowden, and D. M. Kattner. 1988. Survival of mountain lion (Felis concolor hippolestes) in an unhunted population in southwestern Colorado. (Abstract). Proceedings Third National Mountain Lion Workshop, Prescott, AZ. (in press). Bear, G. D. 1989. Seasonal distribution and population characteristics of elk in Estes Valley, Colorado. Colorado Div. of Wildlife, Spec. Rep. No. 65. l4pp. Dailey, T. V., and N. T. Hobbs. 1989. Travel in alpine terrain: energetics of locomotion by mountain goats and bighorn sheep. Zool. (in press). Can. J. Hobbs, N. T. 1988. Obligations and expectations of your peers: manuscript review at the Journal of Range Management. J. Range Manage. 41:368-369. 1988. Estimating habitat carrying capacity: an approach for planning reclamation and mitigation for wild ungulates. Pages 3-7 in Issues and technology in the management of impacted wildlife: proceedings of a national symposium, Colorado S~rings, CO, 1987. Thorne Ecological Inst., Boulder, CO. 1989. Linking energy balance to survival in mule deer: development and test of a simulation model. Wildlife Monograph 37pp. 101. Kufeld, R., D. C. Bowden, and D. Schrupp. 1988. Habitat selection and activity patterns of female mule deer in the Front Range, Colorado. Range Manage. 41:515-522. Miller, M. W., M. A. Wild, B. J. Baker, and A. T. Tu. 1989. Snakebite captive Rocky Mountain elk. J. Wildl. Diseases 25:392-396. Torbit, S. C., L. H. Carpenter, R. M. Bartmann, A. W. Alldredge, and G. C. White. 1988. Calibration of carcass fat indices in wintering deer. J. Wildl. Manage. 52:582-588. J. in mule White, G. C., R. M. Bartmann, L. H. Carpenter, and R. A. Garrott. 1989. Evaluation of aerial line transects for estimating mule deer densities. J. Wild1. Manage. 53:625-635. Prepared by Len H. Carpenter Wildlife Research Leader �7 Colorado Division Wildlife Research July 1989 of Wildlife Report JOB PROGRESS REPORT State of Colorado Project No. Work Plan No. Job. No. ~l 9 Period Covered: Author: Mammals Research W-1S3-R-3 _ Multispecies Mammals Investigations 1 Research Administration July 1, 1988 - June 30, 1989 Len H. Carpenter ABSTRACT Planning and evaluation responsibilities for Colorado's deer and elk programs consumed a large portion of the Wildlife Research Leader's time during FY 88-89. An analysis and summary of the deer and elk seasons for the 3 years 1986-88 was prepared. ��9 MAMMALS I RESEARCH ADMINISTRATION Len H. Carpenter P. N. OBJECTIVE To supervise Project. and administer research on deer, elk, and moose in the Mammals METHODS The position of Research Leader is established to supervise and administer all research conducted for the wildlife species of concern and also to plan and evaluate all statewide deer, elk, and moose programs. SEGMENT OBJECTIVE To supervise Project. and administer research on deer, elk, and moose in the Mammals RESULTS AND DISCUSSION Research administration and supervision for 5 full-time researchers was provided until June 1, 1988. At that time, the Research Leader was temporarily assigned to the position of Acting State Wildlife Manager for Terrestrial Resources in Denver for 6 months. A significant amount of time was devoted to analyzing and summarizing results of the past 3 years of big game hunting seasons in order to make recommendations for the next 3-year season structure. This summary was presented to the Wildlife Commission in May, 1988, and was the basis for Division recommendations for years 1988-90. Prepared by Len H. Carpenter Wildlife Research Leader �Colorado Division of Wildlife Wildlife Research Report July 1989 JOB FINAL REPORT State of Colorado Project No. W-lS3-R-3 Work Plan No. Job. No. _ 5 Period Covered: Author: ~3 Mammals Research Multispecies Investigations Impact of Elk Winter Grazing on Livestock Production July 1, 1988 - June 30, 1989 D. L. Baker, N. T. Hobbs Personnel: G. Bear, M. Miller, B. Gill, L. Carpenter, B. Petch, C. Woodward, J. Ritchie, C. Mehaffy, M. Stevens, B. Seely, H. Seely, L. Lovett ABSTRACT All research results for this segment are summarized in the Mammals 2, WP9A,Jl Report. �11 Colorado Division Wildlife Research July 1989 of Wildlife Report JOB PROGRESS REPORT State of Colorado Project No. _W~-=15~3~-~R~-~3~ _ Mammals Work Plan No. _ Deer Investigations Job No. 7 Period Covered: Author: ~2~ Research Development of Census Methods for deer in Plains Riverbottom Habitats July 1, 1988 - June 30, 1998 R.C. Kufeld Personnel: D. Bowden and numerous Region Employees. Colorado Division of Wildlife Northeast ABSTRACT Seven deer (6 mule deer and 1 whitetail) were radio-collared and eartagged in the South Platte Riverbottom near Sedgwick and near Sterling, Colorado on January 25, and February 17, 1989. Deer radio-collared in the South Platte Riverbottom between Platteville, Colorado, and the Nebraska State Line during January and February, 1987,88, and 89, were located at approximately 2-week intervals throughout the year to determine movements and home range size. Deer in that stretch of the South Platte Riverbottom were counted and classified by sex and age 3 times by 2 observers in a helicopter between January 29, and February 13, 1989. Counts 2 and 3, however, were limited to certain river segments where radio-collared deer occurred. Observers also recorded the number of radio-collared deer they saw during each count. Radiocollared'deer were located by fixed wing aircraft while counts were in progress, so the number of radio-collared deer in the census area was known. The mean portion of radi.o-collared deer seen by observers on 3 counts was 93% for mule deer and 69% for whitetails. Data from count 1 suggest an estimated population, along the South Platte river between Platteville, Colorado, and the Nebraska State Line, of 1890 white-tailed deer and 529 mule deer. The population mean based on. 3 counts was estimated with 95% confidence within 28% for whitetails, and within 29% for mule deer. On count 1 buck/doe ratios were 24/100 and 26/100, and fawn/doe ratios were 75/100 and 93/100, respectively, for white-tailed and mule deer. Based on 3 counts the mean buck/doe ratio was estimated within 56% and 45%, respectively, for whitetails and mule deer, and the mean fawn/doe ratio was estimated, respectively, for the 2 species within 8% and 17%. Misc1assification of radio-collared bucks as does because of lost antlers suggest, however, that these sex and age ratios may be inaccurate. A December time frame for determination of sex and age ratios is recommended. ��13 DEVELOPMENT OF CENSUS METHODS FOR DEER IN PLAINS RIVERBOTTOM HABITATS Roland C. Kufeld P. N. OBJECTIVES 1. To determine seasonal movements mule deer in plains riverbottom and home range size of white-tailed habitats. 2. To develop and test methods for estimating size of deer populations in plains riverbottom habitats. and SEGMENT OBJECTIVES Same as P. N. objectives. ACKNOWLEDGMENTS Numerous personnel from Colorado Division of Wildlife Northeast Region were instrumental in capturing deer and in making aerial deer counts. STUDY AREA The study area is the South Platte River basin extending from Platteville, Colorado, to Nebraska. Riparian vegetation in the floodplain is dominated primarily by cottonwood (Populus sargentii), and willow (Salix §QQ.). The riverbottom is bordered along much of its length by agricultural lands, mainly cornfields. Other stretches are bordered by rangelands dominated by mixed prairie or sand sagebrush (Artemisia filifolia) (Costello 1954). Land status includes both private lands and state-owned wildlife areas. Results from the South Platte should apply to most other plains riverbottom habitats such as those found along the Arkansas River. METHODS AND MATERIALS White-tailed and mule deer were trapped and marked in the South Platte riverbottom near Sedgwick, Colorado, and at Dune Ridge State Wildlife Area near Sterling on January 25, and February 17, 1989. Each deer received a radio-collar and 2 orange, numbered eartags. Deer were captured in Clover traps (Clover 1956) and a drop net. Alfalfa hay and eared corn were used as bait. White-tailed and mule deer, radio-collared in the riverbottom during January and February, 1987 and 1988 (Kufeld 1987, 1988), were located at approximately 2-week intervals throughout the fiscal year. Those deer instrumented in January and February, 1989, were located at about 2-week intervals for the remainder of the fiscal year. �14 Deer were counted 3 times between January 29, and February 13, 1989, in the South Platte Riverbottom between Platteville, Colorado, and the Nebraska State Line, a distance of approximately 310 KID. Counts were made by 2 experienced observers (in addition to the pilot) in a Bell Jet Ranger Helicopter. As the helicopter moved along the river it flew at treetop altitude and followed a zig-zag course from the outer edge of the trees on one side of the river to the outer edge of the trees on the other side. The census area averaged approximately 0.8 KID wide and was partitioned into 31 river segments with a mean length of 10.0 Km (range 3.5 to 21.2 Km). Segment boundaries were bridges that crossed the river. A total count of deer was made in each segment. Each deer was classified by species, sex, and age, and a notation made if a deer was wearing a radio-collar. Every day helicopter counts were conducted a fixed-wing airplane flight was also made to locate deer that had been radio-collared during January and February, 1987 and 1988, and January, 1989, in the South Platte Riverbottom between Platteville, Colorado and the Nebraska State Line. Thus, the number of radio-collared deer available to be seen in the census area while counts were in progress was known, and the proportion of radio-collared deer of each species seen by observers in the helicopter provided an estimate of the accuracy of their count. During flight 1 deer were counted and classified in all river segments to provide continuity with data from counts conducted in prior years. During flights 2 and 3 deer were counted and classified in only those river segments where radio-collared deer occurred in order to provide replicate counts for testing of deer observability. Those were: Highway 34 Bridge in Greeley to Kersey Bridge, Kuner Bridge to Orchard Bridge, Highway 6 Bridge near Merino to Sterling Bridge, Iliff Bridge to Proctor Bridge, and Crook Bridge to Sedgwick Bridge. Percentages of radio-collared white-tailed and mule deer observed during the 3 counts were compared using paired-t tests. Unpaired-t tests were used to analyze sex and age ratio differences between deer species and between counts within species. Differences were considered significant if P ~ 0.05. RESULTS Seven deer were captured and radio-collared in 1989 (Table 1). A computer system for analyzing data from tracking deer that were radio-collared during the course of this study is being prepared. This analysis will be presented in a future report. Deer Counts When helicopter counts of deer along the South Platte River were conducted 32 of the radio-collared deer (18 mule deer and 14 whitetails) were alive. Most radio-collared deer of both species were in the riverbottom census area during all 3 counts (Fig. 1). The remaining radio-collared deer were on the plains away from the river. Presence of snowcover was considered a prerequisite to conducting aerial counts based on previous years of experience in counting deer along the South Platte River. Conditions for counting deer during the 3 helicopter flights were judged mostly very good in that there was 100% snow cover during flights �15 1 and 2. During flight 3 snow cover was 100% from Highway 34 Bridge in Greeley to Masters bridge, 80% from Masters Bridge to Orchard Bridge, 25% from Highway 6 Bridge near Merino to Atwood Bridge, and 100% from Atwood Bridge to Sedgwick Bridge. The percent of radio-collar~d deer seen during the 3 helicopter counts was consistently higher and less variable for mule deer than for whitetails (Table 2). Despite the relatively large difference between deer species in mean percent of radio-collared animals seen, the difference was not significant. Plans called for 5 counts, however, adequate snowcover existed only long enough to complete 3 counts. This lack of significance may have been a result of low sample size. The number of deer of each species recorded during a count was adjusted upward, based on the percent of radio-collared deer seen during that count, to provide an estimate of the total deer population in the area censused. Relative precision of population estimates is based on adjusted total deer seen during the 3 counts in river segments that had radio-collared deer (Table 2). The population mean was estimated within 28% with 95% confidence for whitetails, and within 29% of the mean with 95% confidence for mule deer. On flight 1, which provided a count of deer in all river segments, 529 mule deer were recorded. This represents an estimate of the total mule deer population since 100% of the radio-collared mule deer were seen. On flight 1, 1304 white-tailed deer and 69% of the radio-collared whitetails were observed. The estimated adjusted total number of whitetails is 1890 deer. Population estimates based on flight 1 suggest a composition of 78% white-tailed deer and 29% mule deer along the South Platte river between Platteville, Colorado, and the Nebraska State Line. This compares with mean population estimates (Table 2), that suggest a composition of 71% white-tailed deer and 29% mule deer in those river segments which had deer with radio-collars. Deer Sex and Age Classification Mule deer and whitetail buck/doe ratios in all river segments (flight 1) were 26/100 and 24/100, respectively. No significant differences in buck/doe ratios occurred between counts for either deer species or between mule deer and whitetails on individual counts conducted in river segments which had radio-collared deer (Table 2). Fawn/doe ratios were higher for mule deer (93/100) than for whitetails (75/100) in all river segments (flight 1), as well as in river segments which had deer with radio-collars (Table 2). Fawn/doe ratio differences between mule and white-tailed deer during the 3 counts were not significant, however, nor were differences between counts in fawn/doe ratios for either deer species (Table 2). In the case of both deer species estimating precision for fawn\doe ratios was much better than for buck\doe ratios. Based on 3 counts the mean fawn\doe ratio was estimated within 8% and 17% of the mean, respectively, for whitetails and mule deer with 95% confidence. Conversely, for whitetails and mule deer, respectively, the mean buck/doe ratio was estimated within 56% and 45% of the mean. �16 DISCUSSION The South Platte riverbottom in eastern Colorado presents a rather unique situation for aerial censusing of deer in that the area is very long, narrow and winding. Two species of deer occur, and distribution of both species throughout the area is non-uniform ..The area, because of its shape and deer distribution patterns, is not suited for implementation of a randomized helicopter quadrat census system (Kufeld et al. 1980), or an aerial line transect system (Burnham et al. 1980). Thus, it was deemed more efficient to census the entire area. DeYoung (1985), Beasom et al. (1986), and Bartmann et al. (1986) have shown that during aerial counts of white-tailed and mule deer somewhat fewer than 100% of the deer present are actually seen and recorded. Beasom et a1. (1986) reported accuracy of aerial counts for whitetails was unaffected by sample intensity, but precision increased with percent of the area sampled. Since we sampled the entire area of interest findings of Beasom et al. (1986) suggest the only way to increase our precision is with replicate counts. Replicate counts are subject to economic constraints, and limited by the relatively short period that adequate snow cover normally occurs on the eastern Colorado plains. Sightabi1ity of animals during aerial counts is influenced by factors such as speed, height above ground, transect width, observers, group size and vegetation cover (Caughley et al. 1976, Barnes et al. 1986, Samuel et al. 1987). Aerial deer counts in plains riverbottom habitats should be designed and conducted with these factors in mind. For example, the helicopter should fly at a speed of from 56-72 Kmjhr, and altitude of about 30 m. Zig-zag paths taken by the helicopter across the census area should be sufficiently narrow that there is good visibility of the area between subsequent passes. Observers should be experienced and familiar with the area. Counts should be conducted only in winter when there is 100% snow cover and when leaves are gone from deciduous trees and shrubs. Leon et a1. (1987) found no sex or age bias in the composition of whitetailed deer encountered during helicopter counts in Texas. In our study, however, 2 of 6 (33%) of the radio-collared bucks were repeatedly misclassified as does during all replicate flights where they were seen because they had lost their antlers. This was a result of the late date counts were made. Although the sample of radio-collared bucks was small this suggests that buck/doe classifications made in January and February may be quite inaccurate. Misclassifying bucks as does not only results in a low estimate of the buck/doe ratio, it also causes a low estimate of the fawn/doe ratio. Counts to determine population trends can be made in January and February, but classification counts should be made in December, when bucks still have their antlers and fawns are smaller, so both can be more easily distinguished from does. �17 LITERATURE CITED Barnes, A.G., G.T.E. Hill, and G.R. Wilson. 1986. Correcting for incomplete sightability in aerial surveys of Kangaroos. Aust. Wildl. Res. 13:339348. Bartmann, R.M.,L.H. Carpenter, R.A. Garrott, and D.C. Bowden. 1986. Accuracy of helicopter counts of mule deer in pinyon-juniper woodland. Wildl. Soc. Bull. 14:356-363. Beasom, S.L., F.G. Leon III, and D.R. Synatzske. 1986. Accuracy and prec~s~on of counting white-tailed deer with helicopters at different sampling intensities. Wildl. Soc. Bull. 14:364-368. Burnham, K.P., D.R. Anderson, and J.L. Laake. 1980. Estimation of density from line transect sampling of biological populations. Wildl. Monogr. 72. 202pp. Caughley, G., R. Sinclair, and D. Scott-Kemmis. 1976. Experiments in aerial survey. J. Wildl. Manage. 40:290-300. Clover, M. R. 1956. Single-gate deer trap. Calif. Fish and Game 42:199-201. DeYoung, C.A. 1985. Accuracy of helicopter surveys of deer in south Texas. Wildl. Soc. Bull. 13:146-149. Kufeld, R. C. 1987. Development of census methods for deer in plains riverbottom habitats. Colo. Div. Wild1., Wildl. Res. Rep. July (1):1319. Kufeld, R. C. 1988. Development of census methods for deer in plains riverbottom habitats. Colo. Div. Wildl., Wild1. Res. Rep. July (1):1121. Kufeld, R.C., J.H. 01terman, and D.C. Bowden. 1980. A helicopter quadrat census for mule deer on Uncompahgre Plateau, Colorado. J. Wildl. Manage. 44:632-639. Leon, F.G. III, C.A. DeYoung, and S.L. Beasom. 1987. Bias in age and sex composition of white-tailed deer observed from helicopters. Wildl. Soc. Bull. 15:426-429. Samuel, M.D., E.O. Garton, M.W. Schlegel, and R.G. Carson. 1987. Visibility bias during aerial surveys of elk in northcentral Idaho. J. Wildl. Manage. 51:622-630. Prepared by ~c/4tdA Roland C. Kufeld Wildlife Researcher C. �18 Table 1. Deer tagged along South Platte River near Sedgwick, Colorado, and at Dune Ridge Wildlife Area near Sterling, Colorado, January 25, and February 17, 1989. Eartag number 121 122 123 124 125 126 Species mule mule mule mule mule mule deer deer deer deer deer deer Sex doe doe doe doe doe buck Age when Date captured captured adult adult fawn adult adult adult 1-25-89 1-25-89 1-25-89 1-25-89 1-25-89 1-25-89 Capture Location 2 2 2 2 2 2 mi. mi. mi. mi. mi. mi. E. E. E. E. E. E. Red Red Red Red Red Red Radio -collar attached Lion Lion Lion Lion Lion Lion Bridge Bridge Bridge Bridge Bridge Bridge 149.538 149.252 149.170 149.520 149.262 149.770 Table 2. White-tailed and mule deer seen on January 29 - February 13, 1989, helicopter counts of deer in sections of the South Platte River between Greeley and Sedgwick which had deer with radio collars. Species Flight Whitetail 1 2 3 x SE Mule deer 1 2 3 x SE % of radiocollars seen Total deer seen Adjusted total deera Bucks/ 100 does Fawns/ 100 does 69 83 54 728 748 610 1,055 901 1.129 25 23 16 74 74 70 69% 8% 695 43 1,028 67 21 3 73 1 385 436 335 385 468 385 24 17 19 88 77 81 385 29 413 27 20 82 3 100 93 87 93% 4% 2 aAdjusted upward for the percent of radio-collars seen. Example: 83% of radio-collars seen and 748 total deer seen: 748/.83 - 901 adjusted deer seen. �19 L5 120 _ ~ COUNT 1 Imm:::ul COUNT 2 IZ2I ..... COUNT 3 80 60 40 LL. o UJ " ~ 20 z UJ o a:: ~ 0 WHITETAILS MULE DEER Fig. 1. Percentage of radio-collared deer that were in the South Platte riverbottom census area during all 3 helicopter counts. The remaining deer were on the plains away from the riverbottom. ��21 Colorado Division of Wildlife Wildlife Research Report July 1989 JOB FINAL REPORT State of Colorado Project No. ~W_-~1~53~-R~-~3~ Work Plan No. _:2 Job. No. 10 Period Covered: Author: _ Mammals Research _ Deer Investigations Compensatory Mortality in Mule Deer July 1, 1988 - June 30, 1989 R. M. Bartmann Personnel: T. A. Abbott, J. A. Bendykowski, C. A. Blumberg, J. A. Bonamico, L. H. Carpenter, J. N. Caulkins, K. M. Chociej, S. N. DeRuseau, P. M. H. S. L. J. L. M. Dixon, D. L. Dodd, L. J. Draski, E. M. Grody, K. Holzer, Hooker, S. M. Hotchkiss, A. A. Lippacher, D. F. Norman, Shackleford, D. M. Sinor, S. T. Spon, T. R. Stevens, Tandeski, E. K. Weber, G. C. White, and L. C. Zimmerman ABSTRACT Data from the CB and Ridge Study Areas and the pastures are being analyzed for publication as a Wildlife Monograph. A Program Narrative for a new study of the compensatory effects of harvest in a mule deer population was prepared. An experimental late season was established 1-31 December 1989 on the west end of the Ridge Study Area to begin the population reduction required for the new study. Only 33 deer were checked at 2 check stations around the Ridge Study Area during opening weekends of the 3 regular deer seasons. Sixty-four fawns were radio collared on the Ridge Study Area. Forty mortalities were recorded plus 1 radio failure and 1 premature collar dropoff. Excluding these last 2 deer, fawn survival was 35%.' . ��23 COMPENSATORY MORTALITY IN MULE DEER Richard M. Bartmann P. N. OBJECTIVES 1. Accomplish groundwork necessary to conduct an experimental female deer in a portion of GMU 22. 2. Trap and place radio collars on 120 mule deer fawns each winter years. 3. Operate check stations each year during hunting and hunter participation. 4. Monitor fawn survival rates each winter. 5. Analyze data, publish results, seasons and transfer knowledge harvest for for 5 to measure harvest to management. SEGMENT OBJECTIVES Same as P. N. Objectives. METHODS AND MATERIALS Planning was done in preparation for an expanded study of compensatory mortality in a mule deer population. Some preliminary fieldwork was done to aid in developing this study plan. Two check stations were operated during opening weekends of the 3 regular deer seasons to obtain preliminary data on hunting pressure and deer harvest on the Ridge Study Area. One station was at the Little Hills headquarters and the other at the mouth of Hay Gulch. Sex, estimated age, and weight were recorded for each deer checked. Mule deer fawns were trapped with dropnets and radio collared on the Ridge Study Area in November, 1988, to enable continued estimation of survival rates. Radio signals were monitored several days per week throughout the winter and spring and mortalities checked for cause of death. RESULTS AND DISCUSSION Data collected from the CB and Ridge Study Areas and the pastures are being compiled and analyzed to test relationships relating to the mechanisms of compensatory mortality in Piceance mule deer population. Results will be published as a Wildlife Monograph. A Program Narrative (Work Plan 2, Job 15) was prepared for the study of the compensatory effects of harvest in a mule deer population. This is an �24 expansion of previous work under controlled conditions in the pastures. plan was sent through internal review and submitted to Federal Aid. The A late season was established 1-31 December 1989 on the west end of the Ridge Study Area to begin the population reduction required for the new study. There were 375 licenses issued with each licensee allowed to take 2 antlerless deer. Only 23 of the 33 deer checked at the 2 check stations were killed on the Ridge Study Area. Hunter success may have been negatively influenced by the unusually warm, dry weather that prevailed through all 3 seasons. Two-thirds of the deer checked were killed during the second season (Table 1). The few animals checked provided a grossly inadequate sample for any kind of harvest analysis. Until hunting seasons are liberalized to allow a greater harvest of deer, the expense of equipment and personnel required to staff check stations is not warranted. The same information can be obtained more efficiently from field checks of hunters. Sixty-four fawns were radio collared on the Ridge Study Area in November, 1988, to maintain continuity of survival information until the new study can be implemented. As of 15 June 1989, 40 mortalities were recorded. There was 1 radio failure and 1 premature collar dropoff. With these 2 deer removed from the sample, fawn survival was 35%, which is close to average of the previous 6 yrs. There is a possibility of an additional 4-6 radio failures with fawns that have not been contacted for different lengths of time. A final decision will be made on status of these animals after the 1989 trapping session. Table l. Mule deer checked at 2 check stations around the Ridge Study Area during the 1988 regular deer seasons. Season Bucks First 3 Second 7 14 Third 5 2 Prepared by 'RiChard M. Bartmann Wildlife Researcher Does Fawns 1 1 �Colorado Division Wildlife Research July 1989 of Wildlife Report JOB FINAL REPORT State of Colorado Project No. ~W~-~1~5~3_-~R~-~3 _ Mammals Research Work Plan No. ~2~ _ Deer Investigations Job. No. 11 Period Covered: Author: Testing of Mule Deer Census Methodology July 1, 1988 - June 3D, 1989 R. M. Bartmann Personnel: D. J. Freddy ABSTRACT Due to unfavorable snow conditions on the study area in Middle Park, no work was done on this project. A paper entitled, "Evaluation of Aerial Line Transects for Estimating Mule Deer Densities" was published in Vol. 53, No.3 (July, 1989) of The Journal of Wildlife Management. ��27 TESTING OF MULE DEER CENSUS METHODOLOGY Richard M. Bartmann P. N. OBJECTIVES 1. Select area to be censused. 2-. Fly quadrat count to estimate 3. Fly line transects. 4. Analyze data and publish deer numbers results for comparison. in The Journal SEGMENT of Wildlife Management. OBJECTIVES Same as P. N. Objectives. RESULTS Due to unfavorable snow conditions on the study area in Middle Park, no work was done on this project. A paper entitled, "Evaluation of Aerial Line Transects for Estimating Mule Deer Densities" was published in Vol. 53, No.3 (July, 1989) of The Journal of Wildlife Management. Prepared s by Wildlife Researcher ��29 Colorado Division Wildlife Research July 1989 of Wildlife Report JOB PROGRESS REPORT State of Colorado Project No. _W~-~1~5~3~-R~-~3 _ Mammals Research Work Plan No. _ Elk Investigations ~3~ Job. No. 2 Period Covered: Author: Trapping, Transporting, and Maintenance of Elk at Livestock-Elk Grazing Study July 1, 1988 - June 30, 1989 G. D. Bear Personnel: D. Haskins, C. Woodward, C. Reichert, B. Dupire, J. Madison, R. Harthan J. Haskins, M. Bauman, ABSTRACT A total of 257 elk were trapped near Meeker, Craig, and Hayden, Colorado, to provide cows for stocking the experimental pastures on the Little Snake River Wildlife Area north of Maybell, Colorado. The pastures were stocked with 54 adult cows in late December, which were removed in mid-April. Snow accumulations and cold temperatures made it very difficult for the elk to obtain food. Telemetry-collared elk and visual observations indicated elk occupied the Little Snake River winter range from December through April. The collared elk then migrated to summe r ranges 50~6'O mi east: and 40-60 mi southeast of the study area'. ��31 TRAPPING, TRANSPORTING, AND MAINTENANCE OF ELK AT LIVESTOCK-ELK GRAZING STUDY George D. Bear P. N. OBJECTIVE To provide assistance to the Livestock-Elk Grazing Study near Maybell, Colorado, by capturing and maintaining an experimental elk herd. SEGMENT OBJECTIVE 1. To trap, mark, stock, and maintain 54 adult female elk in the livestockelk grazing pasture complex during the period December 15 to April 20. 2. To determine seasonal movements released from the pastures. of radio-collared elk after they are METHODS AND RESULTS Capturing and Handling of Elk The usual amount of effort was put into repa1r1ng the fences and corrals the elk pens, repairing the elk traps, securing hay and other trapping supplies during late summer and fall. at In late November and December trapsites were established at the following locations: (1) 5 mi southeast of Meeker near the Environmental Plant Center; (2) Trapper Mine - 5 mi south of Craig; and (3) Senica Mine - 10 mi southeast of Hayden. Other sites were baited around Craig with minimal success at attracting and holding elk. Late hunting seasons made the Axial Basin sites unacceptable this year. Portable group-traps, baited with alfalfa hay and salt, were used to capture elk. Details for handling elk at the trap sites and in the corral at the livestock-elk grazing pasture complex are presented in previous Federal Aid Reports. To decrease the stress on the elk while they were removed from the trap, the following activities were eliminated: collection of blood samples, weighing of calves, and eartagging. The results were very positive. Cows taken to the pastures were in much better condition, and it required less manpower and time to handle the elk. A group of 20-30 elk in the trap could be sorted and loaded into stock trailers in approximately 30 mins by 3-4 people. A total of 257 elk (102 cows, 126 calves, 9 yearling cows, 10 spikes, 10 adult bulls) were captured from November 27 to February 3. Fifty-four cows were initially used to stock the experimental pastures (December 12 - January 1). These cows were maintained in the pole-corral 2 days to calm them down, then they were released into the "hub" for 4 days to condition them to electric fences before releasing into the experimental pastures. The elk were in good body condition, and the releases went very well. Additional cows were kept in the pole-corral and hub to be used as replacements, when needed. �32 Snow conditions made it very difficult for the elk in the pastures. There were 12 in of snow on the ground after the pastures were stocked; then an additional 18 in fell from January 1 to January 9. A series of clear days reduced this to 8 in with a very heavy crust by late January. In early February, 30 in of snow fell, and heavy winds created drifts 6-8 ft deep in the ravines. Very little vegetation was exposed, only the taller sagebrush plants. Night-time temperatures ranged from 50° F below zero to 32° F below zero. By late February the snow was reduced to 12-16 in deep with a hard crust. Mild temperatures in early March reduced the snow cover so approximately 5% bare ground was showing. Then several unusually warm days (over 60° F) reduced the snow cover to less than 10% in mid-March. Poa and Stipa showed 1/2 -1 in of new growth by late March. Many of the elk in the high-density pastures showed a very rapid decline in body condition. In late January and early February these elk (30 cows) were removed and new elk released into the pastures. In spite of this exchange, it was necessary to replace 8 elk in the high-density pastures and 3 elk in the low-density pastures during March. Elk were successfully removed from the pastures (April 15-25) by baiting them back into the corral, then releasing them down the alleyway. Only 8 elk crossed the pasture fences this year. Six of these crossings occurred during the February blizzard when snow drifts covered the fences. It was necessary to shovel the drifts away from the fences to prevent more crossings. Decline in the number of elk attempting to cross the fences was attributed to the extended training period in the "hub." Elk Movements Telemetry collars were placed on 6 "replacement elk" released from the pens on March 29. They intermingled with large herds of elk, congregating on ridges 10-20 mi south of the experimental pastures; thus remaining in the area until April. Large herds of elk, 50-500 head, were commonly observed in the vicinity of the study area and along Godiva Rim (approximately 7 mi southeast of the experimental pastures) after December 1, then throughout the winter. As the snow melted and green grass became apparent in April, the elk started moving eastward. By May 1, only a few small bands totalling 30-50 elk could be found in the Godiva Rim area. These scattered remnants had moved from the area by mid-May. The 6 newly collared elk and 5 elk collared the previous year were interspersed in the larger herds. They moved along the juniper-covered ridges south of the study area toward Lay, Colorado (approximately 20-30 mi). One of the newly collared elk died enroute. Then 5 collared elk were tracked eastward to the high summer range on Black Mountain and Slater Creek north of Craig and Hayden, Colorado; an airline distance of 50-60 mi. The other 5 collared elk journeyed southeast to Axial Basin, then eastward up Marapos Creek and Williams Fork to high summer ranges near Sand Peak and Pagoda Peak (40-60 mi from the winter range). These migration patterns are similar to patterns reported previous years for these elk herds. Prepared by ~~ GeOrge: sea; Wildlife ~ Researcher �35 JOB PROGRESS REPORT State of Colorado Project No. Mammals W-Is3-R-2 Research Work Plan No. 3 Elk Investigations Job No. 6 Effect of Elk Harvest Systems on elk breeding biology Period Covered: Author: July 1, 1988 - June 30, 1989 D. J. Freddy Personnel: Dr. M. Miller, DVM, D. Hopper, C. Wetherill, M. Cousins, J. alterman, and G. Byrne - Colorado Division of Wildlife; E. Ryland and Forbes-Trinchera Ranch personnel; N. Walsh, Graduate Student, Colo. St. Univ. ABSTRACT We continued evaluating methods for detecting pregnancy in elk. Serum progesterone concentrations averaged 2.98 ± 0.16 for pregnant and 0.30 ± O.lO(SE) ng/ml for non-pregnant cows ~l yr old based on radioimmunoassays. A threshold level of progesterone in pregnant elk may be 1.5 ng/ml which is considerably lower than published estimates. Reproductive tracts from antlerless elk were collected on the Forbes-Trinchera Ranch and from Game Management Unit 33, White River in December-January 198889. For Forbes-Trinchera, pregnancy rates were 29% for yearlings and 83% for mature cows. Fetal sex ratio was 26M:lsF which differed from the l2M:24F ratio of 1987. Conceptions occurred in the 44-day interval from 14 Sep-27 Oct and median conception date was 26 Sep. For White River, pregnancy rates were 83% for yearlings and 92% for mature cows. Fetal sex ratio was 7M:9F. Conc ep t Lons occur redTn the 39-day interval from 15 Sep-23 Oct and median conception date was 26 Sep . . Lower pregnancy rates and more variable fetal sex ratios suggest Forbes elk have a lower quality plane of nutrition than White River elk. Differences in reproduction between herds appear to be independent of differences in numbers or composition of breeding bulis. Small body weights of yearling cows, calves, and mule deer fawns on Forbes are evidence supporting the hypothesis that forage quality may be limiting reproduction. ��37 EFFECT OF ELK HARVEST SYSTEMS ON ELK BREEDING BIOLOGY David J. Freddy P. N. OBJECTIVE To evaluate effects of harvest systems SEGMENT 1. Evaluate 2. Determine Ranch. methods to determine reproductive on breeding biology of elk. OBJECTIVES pregnancy status of elk. status of both elk and deer on the Forbes-Trinchera 3. Provide assistance to the graduate student project investigating bugling behavior of bull elk on the Forbes-Trinchera Ranch. rutting- INTRODUCTION During the mid-1980s, there was statewide concern that elk reproductive rates were declining because numbers of mature bulls were inadequate for breeding (Freddy 1987b). In response, antler-point restrictions to restrict hunting pressure to branch-antlered bulls were instituted to increase numbers of ~2 year old bulls available for breeding. Objectives of this project were to evaluate methods for pregnancy testing large numbers of elk and to compare reproductive rates in herds subject to different hunting systems. The two herds selected for monitoring were White River and Forbes-Trinchera. In 1985, antler-point restrictions in conjunction with unlimited public hunting pressure were implemented in the White River elk herd. The Forbes-Trinchera Ranch has allowed limited private fee hunting for male elk and deer for the last 20 years. Post-season sex ratios since 1986 have averaged 21 bulls:100 cows:56 calves in the White River and 40 bulls:100 cows:57 calves at Forbes-Trinchera. Yearling bulls comprised 83% and 50% of the post-season bulls observed in the White River and Forbes-Trinchera, respectively. METHODS Pregnancy Testing-Blood AND MATERIALS Assays Blood was collected from antlerless elk by hunters on the Forbes-Trinchera Ranch in the San Luis Valley of southern Colorado from 10-12 and 17-19 December 1988. Hunters were instructed to obtain blood from the thoracic entrance to the chest cavity immediately after harvesting the animal and keep the non-heparinized vials of blood cool until depositing vials at check stations. Blood was received from hunters usually within a few hours of when animals were harvested and kept cool until centrifuging within 24-hrs at which time serum was frozen and stored at -20C. Radioimmunoassays (RIA's) for progesterone concentrations were completed in May 1989 by the Physiology Laboratory, Colorado State University, Ft. Collins, Colorado. �38 Fetal Collections Reproductive tracts of female elk were collected by hunters on the ForbesTrinchera Ranch on 10-12 and 17-19 December 1988 and in Game Management Unit 33 (GMU) , White River, in December 1988 and January 1989. GMU 33 represents part of the White River elk population and is located near Rifle, westcentral, Colorado. Tracts were deposited at check stations and kept cool until processing. Pregnancy status was determined from the presence of fetuses, embryos, and developed uterine tissue. Questionable uteri were preserved for later examination. Fetal measurements were made on fresh specimens (subsequently preserved) and followed definitions of Armstrong (1950). Fetal age was determined from growth curves of Morrison et al. (1959). Compliance with the request to collect reproductive organs and blood was excellent and generally, hunters had few problems understanding collection instructions they had previously received by mail (Freddy 1987a). Disease Survey Blood serum samples from elk and deer on the Forbes-Trinchera Ranch were screened in May 1989 for presence of brucellosis and leptospirosis. Elk samples were collected in December 1987 and 1988 and deer samples were obtained in March 1988. All samples were kept at -20C prior to processing. Brucellosis tests were completed by the USDA Laboratory, Denver, CO and leptospirosis tests were done by the Veterinary Diagnostic Laboratories, Colorado State University, Ft. Collins, CO. Forbes-Trinchera Elk and Deer Harvests Male elk and deer were harvested during seasons running from early September into early-December by hunters paying a fee. Eviscerated body weights (head, legs, and hide attached), antler weights, and antler scores (Boone & Crockett) were obtained for bulls and bucks in 1987 and 1988. Antler weights included the frontal bone. Ages of males harvested 1986-88 were based on replacement and wear with dental cementum used secondarily (Freddy 1988). Female elk and deer were harvested in mid-December by hunters participating in the Wildlife Ranching Program. Eviscerated body weights, body measurements, and ages were obtained at mandatory check stations in 1987 and 1988. For 1986-88, ages of antlerless elk were based on dental cementum while ages of antlerless deer were based on replacement and wear for fawns and yearlings and dental cementum for females ~2 yrs old (Freddy 1988). RESULTS AND DISCUSSION Pregnancy Testing Serum progesterone concentrations averaged 2.98 ± 0.16 for pregnant and 0.30 O.lO(SE) ngjml for non-pregnant cows ~l year old collected during December on the Forbes-Trinchera Ranch (Table 1). Progesterone levels in calves averaged 0.85 ± 0.48 and 1.26 ± 0.74(SE) ngjml for females and males, respectively with maximum levels of 6.03 ngjml. The erratic and elevated levels in calves may reflect increased cortisol levels associated with stress from the hunting season (Freddy 1988, Plotka et al. 1983). Progesterone levels were not related to age of pregnant cow (r - -0.08, slope - 0, P>0.50). ± �39 Weber et al. (1982) reported threshold levels of progesterone in pregnant elk of 3.7 ng/ml. Progesterone levels measured in several groups of elk (Freddy 1988) suggest pregnancy commonly occurs with levels below 3 ng/ml. Progesterone concentrations can deteriorate if samples are not properly cooled. A concern, therefore, with samples collected by hunters is that progesterone levels decline between time of death and storage. In 1988, hunter samples were assigned to 3 categories of time between death of the cow and freezing of serum: <24, <14, and <8 hrs. Progesterone concentrations were not affected by time since death (P>0.50, ANOVA) using these coarse demarcations of time. Therefore, we consider these lower levels of progesterone to be accurate. A more appropriate threshold level for progesterone in pregnant elk may be 1.5 ng/ml (Fig. 1). At this time, serum RIA's are preferred over qualitative pregnancy tests (Freddy 1988) because more objective criteria for determining pregnancy status can be developed. We also recommend not using serum progesterone to judge pregnancy status of calves. Fetal Collections-Forbes Pregnancy Elk Rates Pregnancy rates for adult cows (~l yr old) averaged 78% with a range of 7782% from 1986-88 (Table 2). Pregnancy rates approached 90% for prime-aged adults but were 20% for yearlings and <70% for cows aged 11+ years. Pregnancy was not observed in calves. Litter size was 1 in all but 2 (2%) of 113 litters. Two sets of twins, consisting of 2 females and 1 male and 1 female, occurred in cows 9 and 12 years old, respectively, in 1986. Infected uteri not capable of supporting pregnancy occurred in 4 (3%) of 144 adults examined. Infections were in 1 yearling and 3 cows ~13 years old with 3 found in 1986 and 1 in 1988. Fetal Sex Ratios Fetal sex ratios deviated from unity in 1986 and 1987 (X~ P~0.04) and tended to favor males in 1988 (X~ P-0.08). Pooled among all years, fetal ratios were 55M:45F which did not differ from 50M:50F (X~P>0.25) (Fig. 2, Table 3). However, ratios differed among years (X~P-0.004), favoring males in 1986 and 1988 and females in 1987. Fetal sex ratios in mule deer collected on the Ranch also alternated from male to female between 1986 and 1987 (Freddy 1988). Yearly changes in fetal sex ratios could reflect differences in age or body condition of collected cows as fetal sex ratios favoring males are associated with older and dominant cows (Clutton-Brock 1986). Ages of adult cows collected at Forbes-Trinchera were not different among years (ANOVA P>0.50, or X~ P>0.30) (Fig. 3). However, ratios shifting from female to male were associated with increasing weights of cows from 1987 to 1988 (Fig. 4). Changes in weights of cows (P-0.12) represent changes in tissue and not skeletal mass because total body and hind foot lengths were not different between years (P>0.40). Body weight influencing fetal sex was suggested by a marginal interaction of cow weight with fetal sex (P-0.13) and a main effect of yearly weight (P~0.06, ANOVA). �40 Fetal Size Although male fetal weights and crown-rump lengths tended to be larger than females, males were significantly larger only in 1987 (P~0.002; Figs. 5, 6). Male fetal weights and lengths were disproportionatly larger in 1987 (P~0.04, year x sex interaction, ANOVA) when body weights of cows were smallest and fetal sex ratios favored females (Figs. 2, 4). Why male weights and crownrump lengths were greater in 1987 than 1988 (P~0.005), unlike female weights and lengths that remained unchanged (P>0.30), cannot be explained. Fetuses were smaller in 1986 because collections occurred 14 days earlier than in 1987-88. Conception Dates Conceptions occurred primarily between 14 September and 27 October during all 3 years. Median dates of conception were 26, 28, and 28 September for 198688, respectively and 28 September for all years (Fig. 7). At least 97% of the conceptions occurred yearly within a 33-44 -day interval. Conception date was not related to cowage based on linear regression of fetal age on cowage (r- -0.003, n-l09). However, the data suggested that a curvilinear model warrants further analysis. Nevertheless, late breeding cows were arbitrarily defined as the last 25% of the cows breeding yearly. For all years, 64% of these cows (n-25) were ~4 years old and 8% were 11+ years old. This may suggest that young cows have difficulty achieving a threshold body mass adequate for breeding, either initially or after sustaining a pregnancy and lactation. Fetal age was the same for male and female fetuses in both 1986 and 1988 (P >0.40) but in 1987, male fetuses were about 7 days older than females (P=0.002). These comparisons assume identical growth rates for male and female fetuses. Fetal Collections-White Pregnancy River Elk Rates Pregnancy rates for adult cows (~l yr old) collected in GMU 33 averaged 91% with a range of 89-92% from 1987-88 (Table 4). Pregnancy rates were 63% for yearling cows, greater than 90% for prime-aged cows, and 100% for cows 11+ years old. Rates for yearlings and old cows were higher than those observed at Forbes-Trinchera (Table 2). These rates may not be typical of the entire White River elk population, as elk collected in GMU 33 were associated with agricultural damage problems and may have a higher plane of nutrition than elk subsisting on native forage. Neither twins nor infected uteri were observed. Fetal Sex Ratios Fetal sex ratios did not differ from unity in either year or years pooled (X~ P>0.40) and were not different between years (X~P>0.40). The pooled fetal sex ratio was 53M:47F (Table 5). �41 Fetal Size Comparing fetal weights between sexes and years was precluded by the variable dates over which fetuses were collected. Fetuses from GMU 33 (Appendix 1) were collected primarily in the last 15 days of December in 1987 and 1988 and weighed about 250g at an average fetal age of 90 days. At this fetal age, Forbes-Trinchera fetuses would weigh about 2l0g based on a fetal weight vs. age growth curve. This preliminary comparison suggests fetal growth rates may be slower on the Forbes Ranch. Conception Dates Conceptions occurred between 3 September and 27 October in both 1987 and 1988. Median dates of conception were 20 and 26 September for 1987 and 1988, respectively and 20 September for all years (Fig. 8). Conceptions occurred within a 39-day interval both years. Variable median dates occurred when ages of cows remained unchanged (P>0.40), although average cow ages were 5.9 and 5.0 yrs in 1987 and 1988, respectively. Late breeding cows were again arbitrarily defined as the last 25% of the cows breeding yearly. For both years, 58% of these cows (n-12) were ~3 years old and 8% were 11+ years old. Summary There appear to be both differences and similarities in reproduction between Forbes-Trinchera and White River elk populations. Pregnancy rates for yearling and old cows were higher, fetal sex ratios were more consistent, and median conception dates were more variable in the White River than the ForbesTrinchera population. However, fetal sex ratios pooled over years tended to favor males in both populations and "late breeding" cows were composed of similar aged cows. A higher plane of nutrition in the White River is offered as a potential hypothesis for differences between popUlations. A principal premise of this hypothesis being that reproduction in yearling and old cows best reflects nutritional capabilities of habitats. Yearlings and old cows in both populations conceive but conception was higher for these age classes in the White River. Many of the "late breeders" in both populations were yearlings, young cows, and old cows. A second hypothesis follows that with better nutrition more young and old cows conceive and the breeding interval may be lengthened or become more variable among years as habitats could vary in quality yearly. Variable median breeding dates in the White River, compared to Forbes-Trinchera, were somewhat supportive of this argument. The consistency in median breeding dates at Forbes-Trinchera could therefore reflect a static lower quality plane of nutrition and that only prime aged cows consistently conceive. An alternative explanation could argue that the higher percentage of mature bulls .on the Forbes-Trinchera synchronizes breeding which results in more consistent median breeding dates, but this argument cannot explain the lower conception rates in yearling and old cows observed in this population. If late breeding is a function of available bulls, then antler-point restrictions that recruit 2-year old bulls for breeding still result in variable breeding dates as suggested by the White River data. �42 Fluctuations in fetal sex ratios at Forbes-Trinchera may also reflect variable nutritional status of cows. The general trend for both populations to conceive more male calves follows the pattern observed in many other ungulate populations. Post-season calf:cow ratios were nearly identical for both popUlations. Assuming a higher pregnancy rate in the White River, this may suggest that survival rates for calves are lower in the White River. Fetal Collections-Forbes Deer Collections of female mule deer for reproductive and physiological measurements did not occur as planned in March 1989. A large-scale poaching "raid" was conducted by the U.S. Fish and Wildlife Service Colorado Division of Wildlife in the San Luis Valley in early March Scientific collection of deer during the aftermath of this raid was appropriate. antiand the 1989. not deemed Disease Surveys All serum samples from elk and deer on the Forbes-Trinchera Ranch tested negative for brucellosis. The 72 elk samples were from 48 adult females, 11 yearling females, 10 female calves, and 3 male calves. The 12 deer samples were from 11 adult females and 1 yearling male. All serum samples from elk and deer also tested negative for the following 5 strains of leptospirosis: L. hardjo, L.ictero, L. canico, L. grippo, and ~ pomona. The 55 elk samples were from 44 adult females, 7 yearling females, 1 female calf, and 3 male calves. The 12 deer samples were from 11 adult females and 1 yearling male. Forbes-Trinchera Hunter Harvests Age distribution of bulls harvested by fee hunters was consistent from 198688 (Fig. 9). Average a~e and frequency by age class were not different among years (P>0.50, ANOVA, XlY. Average age of all bulls harvested was 4.8 ± O.l(SE) yrs. Age distribution of female elk harvested during late seasons was consistent from 1986-88 (Fig. 10). Average age and frequency by age class were not different among years (P>0.40, ANOVA, X~0. Yearly average ages of female elk ranged from 4.3-5.3 years, inclusive of calves. Average age of male deer harvested by fee hunters was younger in 1986 than 1987-88 (P<O.OOl, ANOVA) reflecting that more bucks in age classes 8+ were harvested in 1987-88 (P<O.Ol, X~2 (Fig. 9). Although total harvest increased among years, the shift to older aged males is thought to reflect changes in timing of seasons. In 1986, deer hunting ceased in early-November, prior to rut, but in 1987-88 seasons continued to early-December during the rut when older bucks were assumed to be more vulnerable. Average age of all bucks harvested was 6.3 ± O.lO(SE) yrs. �43 Age distribution of female deer harvested during late seasons was consistent from 1986-88 (Fig. 10). Average age and frequency by age class were not different among years (P>0.40, ANOVA, X~O). Average age of female harvested was 3.1 yrs, inclusive of fawns. Forbes-Trinchera Antler Scores and Body Weights Gross antler score, antler weight, and eviscerated body weight of bulls steadily increased through age 7 (Fig. 11). At age 8+, antler measurements and body weight tended to decline depending on collection year (Fig. 11). Eviscerated body weights of antlerless elk stabilized at lSO-lS5kg at age 4 (Fig. 13), or 200-207kg whole body weight assuming eviscerated weight equals 75% of whole body weight (Blood and Lovass 1966). Projected whole body weights of yearling females were 125 and l49kg for 1987 and 1988, respectively. These projected weights are below the l52kg threshold reported by Greer (1966) for pregnant yearlings in Yellowstone National Park and is commensurate with the low pregnancy rates observed in yearlings (Table 2). Projected whole body weights for male and female calves combined was 86kg in both 1987 and 1988. Whole body weights for male and female calves combined averaged 110, 116, lOS, and 9lkg, respectively for White River (GMU 23, Dec 1987), and North Park, Durango, and Creede, Colorado, (Jan-Feb 1986) (Bear 1988, CDOW unpubl. data). This general statewide north-south decline in calf weights may reflect differences in total forage/animal unit and/or genetic differences among herds. Gross antler score, antler weight, and body weight tended to increase with age of buck, but not to the degree that occurred with bulls (Figs. 11, 12). Marginal increases in antler score and body weight occurred after ages 6 and 5, respectively. Increases in antler weight but not score after age 6 reflects heavy beamed, short height, and multiple-tined antlers common to older bucks. The trend for body weight of bucks to stabilize at 80kg across all ages (Fig. 12) might suggest nutritional limitations on growth when compared to the steady growth curve presented by Anderson et al. (1974) for bucks in the Poudre River of northern Colorado. However, the 80kg weight is greater than weights projected by Anderson et al. (1974) for all age classes of males and therefore, likely reflects the bias of hunters to select larger bodied bucks from all age classes. Eviscerated body weights of antlerless deer stabilized at 43-45kg at age 3 with a marginal decline occurring at ages 7+, while eviscerated weights of fawns and yearlings were 23-24kg and 34-38kg, respectively (Fig. 13). Anderson et al. (1974) projected peak eviscerated weights of 24kg for fawns, 37kg for yearlings, and 52kg for adult females in the Poudre River which suggests that Forbes-Trinchera adult females could be undersized. Projected whole body weights of fawns was 33kg, assuming eviscerated weight equals 71% of whole body weight (Anderson et al. 1974). Weights of fawns, therefore, probably did not exceed the 33kg fawns of the Piceance Basin, Colorado (Torbit et al. 1988) where starvation in moderate winters accounted for >50% of the over-winter fawn mortality (White et al. 1987). �44 Summary Stability in ages of bulls, bucks, cows, and does harvested suggests that the Forbes-Trinchera populations are capable of supporting current levels of hunter harvest and selection (Appendix 2). The shift to older aged bucks harvested in 1987 and 1988 compared to 1986 demonstrates the effect of season timing on age structure of harvest. Steady increases with age in body size, antler weight, and antler score of bulls is commensurate with expected trends. However, the apparent stability in antler score of bucks after age 6 might argue for short-term increases in the harvest of older bucks to lower the average age of the buck population. A nutrition-density relationship that may be negatively affecting both deer and elk is suggested by elk calves and deer fawns smaller than those measured in other populations in Colorado and yearling elk cows weighing less than considered adequate for breeding. Reducing animal densities or increasing quality and quantity of forage appear to be appropriate management strategies to consider. Literature Cited Anderson, A. E., D. E. Medin, and D. C. Bowden. 1974. Growth and morphometry or the carcass, selected bones, organs, and glands of mule deer. Wi1dl. Monogr. 39. 122pp. Armstrong, R. A. 1950. Fetal development Amer. Mid. Nat. 43:650-666. Bear, G. D. 1988. livestock-elk 40. of northern white-tailed deer. Trapping, transporting, and maintenance of elk at grazing study. Colo. Div. Wildl. Game Res. Rep. Ju1y:33- Blood, D. A., and A. L. Lovass. 1966. Measurements and weight in Manitoba elk. J. Wildl. Manage. 30:135-140. relationships Clutton-Brock, T. H., S. D. Albon, and F. F. Guiness. 1986. Great expectations: dominance, breeding success and offspring sex ratios in red deer. Anim. Behav. 34:460-471. Freddy, D. J. 1987a. Effect of elk harvest systems on elk breeding Colo. Div. Wildl. Game Res. Rep. Ju1y:101-120. 1987b. The White River elk herd: Div. Wild1. Tech. Bull. 37. 64pp. a perspective 1960-1985. 1988. Effect of elk harvest systems on elk breeding Div. of Wild1. Game Res. Rep. July:43-75. biology. Colo. biology. Greer, K. R. 1968. Special collection-Yellowstone elk study, 1967-68. Dep. Fish and Game Fed. Aid Job Comp1. Rep. Prog. W-83-R-11. Colo. Mont. �4:) Morrison, J. A., C. E. Trainer, and P. L. Wright. 1959. Breeding elk as determined from known-age embryos. J. Wi1d1. Manage. seasons in 23:27-34. Plotka, E. D., U. S. Seal, L. J. Verme, and J. J. Ozoga. 1983. The adrenal gland in white-tailed deer: a significant source of progesteFone. J. Wildl. Manage. 47:38-44. Torbit, S. C., L. H. Carpenter, R. M. Bartmann, A. W. Alldredge, and G. C. White. Calibration of carcass fat indices in wintering mule deer. J. Wildl. Manage. 52:582-588. Weber, B. J., M. L. Wolfe, and G. C. White. 1982. Use of serum progesterone levels to detect pregnancy in elk. J. Wildl. Manage. 46:835-837. White, G. C., R. A. Garrott, R. M. Bartmann, L. H. Carpenter, and A. W. Alldredge. 1987. Survival of mule deer in northwest Colorado. J. Wild1. Manage. 51:852-859. /1 Prepared 1/<;' '/ //! by ~/~:.~/~_/~_(~t_t __ 1~/,_/~t_~~~_~~_//'_-+t! David J / Freddy / Wildlife Researcher _ �46 Table 1. Serum progesterone (ng/ml) in elk collected by hunters on the Forbes-Trinchera Ranch in December 1987 and 1988. Statistic 1987 Mean SE min max n 3.20 0.24 0.75 6.79 34 statistic Mean SE min max n a Adults Pregnant 1988 2.82 0.21 0.03 6.31 43 Non-Pregnant Male Adults Non-12regnant 1987-88° 2.98 0.16 0.03 6.79 77 0.30 0.10 0.02 2.14 21 Calves 1987-88 Female 1.26 0.74 0.02 6.03 8 aExcludes obvious outlier of 14.86 ng/ml bNo difference between years P = 0.24 1987-88 0.85 0.48 0.06 2.70 5 �47 Table 2. Pregnancy rates for age classes of female elk collected on the Forbes-Trinchera Ranch in December 1986-88. Agea (yrs) 1986 n Preg 0.5 1 2 3-4 5-6 7-8 9-10 11-12 13-17 Totals Totals 1+ 1 6 7 6 3 4 1 2 5 0 2 7 6 3 4 1 35 34 1987 n Preg Year 1988 n Preg 1986-88 Preg %Preg n 3 3 7 5 15 10 5 3 1 3 0 0 5 15 9 4 3 0 2 2 7 6 19 12 8 2 0 7 0 2 4 17 11 7 2 0 4 6 20 18 40 25 17 6 3 15 0 4 16 38 23 15 6 2 9 0 20 89 95 92 88 100 67 60 28 28 52 49 38 38 63 61 47 47 150 144 113 113 78 2 aAge for ~2 from replacement cementum. and wear, for 3+ from dental Table 3. collected Fetal sex ratios for age classes of female elk on the Forbes-Trinchera Ranch in December 1986-88. Agea (yrs) 1986b M F 1 1 1 4 3 3 2 3-4 5-6 7-8 9-10 11-12 13-17 Totals Total Fetuses 0 2 3 17 0 2 1 0 0 2 1 U M 1 4 1 0 1 0 3 3 2 0 0 0 0 2 1 0 1 6 7 12 30 1987 F 1988 F U M 1 2 8 8 5 1 0 2 5 3 0 0 1 0 0 1 0 0 1 0 0 1 24 2 26 0 2 11 7 2 1 0 38 U 1986-88 M U F Male 2 4 4 0 1 1 0 2 0 0 0 2 0 6 6 15 17 13 10 10 4 2 4 2 1 5 3 0 100 50 47 57 71 33 67 63 15 3 55 45 12 55 2 1 44 1 0 2 0 0 112 for ~2 from replacement and wear, for 3+ from dental cementum. bFetal sex M=male F=female U=unknown. aAge 9,-0 �48 .Table 4. Pregnancy rates for age classes of female elk collected in GMU 33 . White River. in December 1987-88. Year Agea (yrs) 1987 n Preg 0.5 1 2 3-4 5-6 7-8 9-10 11-12 13-19 0 2 6 7 13 5 0 0 4 0 0 6 7 12 5 0 0 4 0 6 2 4 1 2 0 1 2 0 5 1 4 1 2 0 1 2 0 8 8 11 14 7 0 1 6 0 5 7 11 13 7 0 1 6 100 100 37 37 34 34 18 18 16 16 55 55 50 50 91 Totals Totals 1+ 1988 n Preg 1987-88 Preg %Preg n a Ages for 1987 from dental cementum and wear. 63 88 100 93 100 and for 1988 from replacement Table 5. collected Fetal sex ratios for age classes of female elk in GMU 331 White Riverl in December 1987-88. Agea (yrs) 1987b M F U M 1988 F U 1987-88 U M F 1 2 3-4 5-6 7-8 9-10 11-12 13-19 Unkown 0 4 2 6 4 0 0 2 2 0 1 5 6 1 0 0 2 0 0 1 0 0 0 0 0 0 0 2 0 1 0 1 0 1 2 0 3 1 3 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 2 4 3 6 5 0 1 4 2 Totals 20 15 1 7 9 0 Total Fetuses 36 16 % Male 3 2 8 7 2 0 0 2 0 0 1 0 0 0 0 0 0 0 40 67 27 46 71 100 67 100 27 24 1 52 .52 for 1987 from dental cementum and for 1988 from replacement and wear. bFetal sex M=male F=female U=unknown. aAge �49 Appendix 1. Measurements of elk fetuses from Forbes-Trinchera Ranch, 1986-88, and from white River GMU 33, 1987-88, Colorado. Herd/ Year/ Statistic Body Weight Cg) Male Female Crown-Rump Length (mm) Male Female Hind Foot Length (mm) Male Female Forbes 29 Nov-5 Dec 1986 Mean SD min max n 27.6 13.8 12.2 58.5 17.0 20.9 7.0 11.9 29.0 6.0 90.2 16.7 63.5 115.5 17.0 86.0 9.5 72.0 94.0 5.0 20.5 4.8 13.5 28.5 17.0 19.8 2.7 16.5 60.4 33.2 12.0 135.0 24.0 141.4 21.1 113.0 180.0 12.0 115.4 23.3 66.0 151. 0 24.0 42.3 10.9 31.0 68.0 12.0 30.3 8.8 66.7 29.7 23.0 120.0 15.0 120.0 19.9 77.0 163.0 26.0 121. 7 17.9 87.0 150.0 15.0 32.6 7.7 17.0 47.0 26.0 239.2 139.0 140.0 510.0 6.0 184.8 42.0 105.0 230.0 14.0 188.3 33.7 165.0 255.0 6.0 56.6 16.3 59.8 12.3 25.0 47.0 75.0 14.0 80.0 5.0 279.0 166.1 62.0 470.0 6.0 152.8 18.9 140.0 180.0 182.5 44.0 122.0 221.0 6.0 44.5 9.1 36.0 57.0 58.8 21.5 30.0 23.0 5.0 Forbes 12-14 & 19-21 Dec 1987 Mean SD min max n 118.7 54.7 66.0 242.0 12.0 14.0 46.0 24.0 Forbes 10-12 & 17-19 Dec 1988 Mean SD min max n 74.5 35.2 22.0 162.0 26.0 33.1 7.0 20.0 45.0 15.0 White River GMU 33 4-31 Dec 1987 Mean SD min max n 257.9 123.6 49.0 415.0 14.0 White River GMU 33 17-31 Dec 1988 Mean SD min max n 136.3 42.5 103.0 195.0 4.0 4.0 4.0 80.0 6.0 �50 Appendix 2. Numbers of elk and deer harvested 1986-88. Trinchera Ranch a Reg. Season on the Forbes- Late sea son'' Species Adult Male Adult Male Adult Female 1986 1987 1988 Elk Elk Elk 72 93 87 3 6 3 34 51 65 1 6 8 1 4 7 0 0 0 1986 1987 1988 Deer Deer Deer 87 109 108 8 6 5 50 118 117 1 7 6 11 14 9 3 Yr Male Young Female Young Unk. 0 0 Regular season refers to fee hunting seasons: 13 Sep-9 Nov 1986, 5 Sep-9 Oct and 14 Nov-l1 Dec 1987, 10 Sep-9 Dec 1988. a Late-season refers to public hunting seasons under the wildlife Ranching Program: 29 Nov-5 Dec 1986, 12-14 and 19-21 Dec 1987, 10-12 and 17-19 Dec 1988. All animals processed at check stations. b �51 100 ,, ,, I- Z UJ ,----------' 80 o a: UJ o, 60 UJ > ~ => :E => o 40 PREGNANT 20 ------. o o n NON-PREGNANT 2.0 3.0 4.0 PROGESTERONE ng/ml 1.0 = 78 n = 21 5.0 6.0 Fig. 1. A threshold of 1.S ng/ml serum progesterone may be appropriate for differentiating pregnant and non-pregnant adult elk. 60 MALE 50 en UJ en 40 tuu. 30 :5 w 20 ~ FEMALE => 10 o 1986 1987 1988 ALL YEAR Fig. 2. Fetal sex differed from SOM:50F yearly (P~ 0.08) but not over all years (P>0.40). Fetal sex alternately favored males and females (P < 0.004) on the ForbesTrinchera Ranch, 1986-88. �52 10 -ea:n 9 w 7 -c C 8 o w 6 -c 5 3: 4 o 3 0 ~ ...J w 28 38 44 1987 1988 2 1 0 1986 YEAR Fig. 3. Ages of elk cows with fetuses were stable among years (P>O.50) on the ForbesTrinchera Ranch, 1986-88. Sample sizes above vertical lines showing + 2(SE). en -::r: 160 41 (!) ~ I- o w 31 150 3: 3: 0 o ~ ...J 140 w 130 1987 1988 YEAR Fig. 4. Weights of elk cows with fetuses tended to increase in 1988 (P=O.12) on the Forbes-Trinchera Ranch. Sample sizes above vertical lines showing +2(SE). �53 160 -(!) J- J: (.!J ....J 80 UJ 60 u.. ~ ....J UJ ~ FEMALE 120 100 s MALE 140 UJ ;: 12 40 26 15 45 17 6 20 0 1986 1987 1988 ALL YEAR Fig. 5. Male and female fetal weights were different only in 1987 (P<O.001) on the Forbes-Trinchera Ranch. Sample sizes above vertical lines showing +2(SE). -::E ~ a.. ::E ::> MALE 140 120 ;: 100 o a: o 80 ....J 60 ~ 40 u.. FEMALE 160 a:, z ~ 20 o 1986 1987 1988 ALL YEAR Fig. 6. Male and female fetal crown-rump lengths were different only in 1987 (P<O.002) on the Forbes-Trinchera Ranch. Sample sizes above vertical lines showing +2(SE). �54 50 III en Z 0 ln, W ~ YEARLY MEDIAN DATES 40 1986 ~ n = 26 30 1987 n 37 = o 1988 n= 44 o Z 0 o I- 20 Z w o c: W 10 a. 0 9/8 9/18 9/28 10/8 10/18 10/28 11/7 11/17 40 • en z 0 MEDIAN DATE 30 •• ICl. UJ o Z 0 o 20 1986-1988 n = 107 I- Z UJ o 0: UJ Cl. 10 o 9/8 9/18 9/28 10/8 10/18 10/28 11/7 11/17 MONTH AND DAY (Begin 5-day intervals) Fig. 7. Median conception date for elk was consistent among years (TOP) and was 28 September for all years (BOnOM) on the Forbes-Trinchera Ranch, 1986-88. �55 50 I 40 I )c )c )c )c z I0W 0 Z 0 30 f- ~ ~ x 0 >: x 20 x r-- 0 Z W 0 a: 10 w f-- ~ 00 I I L...- 9/8 tx tx tx tx tx tx tx ~ )< )< )< n = 16 ~ ~ ~ ~II I 9/18 1988 )c )< )< )c )< )< )c )c ~ ~ ~ n = 36 x )< )< )< )< Dr: 111987 )c x x x ~ I- YEARLY MEDIAN DATES ~ en 0 -==. 9/28 I 10/8 I 10/18 I I 10/28 r T T 11/7 I 11/17 40 • en Z MEDIAN DATE 30 1987-88 n = 52 0 b:UJ 0 Z 20 0 0 I- Z UJ 0 a: 10 UJ 0- o 9/8 9/18 9/28 10/8 10/18 10/28 11/7 11/17 MONTH AND DAY (Begin 5-day intervals) Fig. 8. Median conception date for elk varied about 1 week between years (TOP) and was 20 September for all years (BOnOM) in GMU 33, White River, 1987-88. �56 - 1986 n = 72 ~1987 AVG.AGE '" 4.8 30 n = 93 [2LJ1988 n = 87 AVG. AGE = 4.8 AVG. AGE = 4.9 BULLS ~ Z 20 UJ ::> o UJ c:: L1. 10 o 2 3 5 4 1986 n = 87 30 ~ ~ 7 8+ 1987 n = 109 ~ AVG. AGE •• &.& AVG. AGE", 5.& 25 6 1988 n = 108 AVG. AGE. = 6.8 BUCKS 20 Z UJ ::> o 15 LU c:: L1. 10 5 o 1-3 4 5 6 7 8 9+ AGE (YEARS) Fig. 9. Ages of bulls harvested on the Forbes-Trinchera Ranch were consistent among years (P>O.50) (TOP) while younger bucks were harvested in 1986 (P=O.01) (BOnOM). �57 30 1986 n = 35 FEMALE ELK AVG. AGE = 5.3 B;83 1987n=61 AVG. AGE = 4.3 20 ~ 1988 n = 71 ~ AVG. AGE = 4.9 Z W :::> 0 w a: u, 10 0 2-3 0 4-5 6-8 9-20 50 III FEMALE DEER 1986n=61 AVG. AGE = 3.1 40 1987 n = 127 ~ AVG. AGE = 3.1 0 ~ Z W 1988 n = 124 30 AVG. AGE = 3.2 :::> 0 w c: U. 20 10 o o 2 3 4 5 6 7+ AGE (YEARS) Fig. 10. Ages of female elk (TOP) and deer (BOnOM) harvested on the ForbesTrinchera Ranch were consistent among years (P>0.40). Male calves and fawns not included. �58 400 w 350 CC 300 o en 250 CC 200 o w .=z « I)•• BULLS 1987 n = 83 ~ 1988 n = 83 150 100 50 o - 2 3 4 5 6 15 IE 1987 n BULLS -J: 7 ~ ~ 8+ = 83 1988 n = 83 •••• 10 (!) w 3: c:: ~ 5 !z-c o 2 3 300 4 5 6 7 8+ 7 8+ & 1987n = 83 6250 -s: :::.:::: 200 o w 150 3: >Q o CO 100 50 o 2 3 456 AGE (YEARS) Fig. 11. Average gross antler score (TOP), antler weight (MIDDLE), and eviscerated body weight (BOTTOM) for bulls harvested on the Forbes-Trinchera Ranch. �59 200 c: 180 o en 160 L1J 1987 n = 102 - BUCKS 1988 n = 102 ~ o c: ~ 140 I- Z ~ 120 100 - 5 2 3 4 5 6 BUCKS 7 8 1987 n = 102 1988 n = 102 ~ ~ 9+ I- 4 J: 3 (!:) L1J ~ c: 2 ~ !z~ 1 o 140 2 3 4 5 6 7 BUCKS 8 IQQg 9+ 1987 n 1988 n 8'120 = = 102 102 ~ -100 a I- ~ s g 80 60 40 20 o 2 3 456 7 8 9+ AGE (yEARS) Fig. 12. Average gross antler score (TOP), antler weight (MIDDLE). and eviscerated body weight (BOnOM) for bucks harvested on the Forbes-Trinchera Ranch. �60 175 ~ ANTLERLESS ELK ,. 1987 n = 50 ~ 1988 n = 85 150 125 l- I C!J 100 w ~ >- 75 a co 50 c 25 o 50 8' - o 2-3 1 4-5 9-20 6-8 III 1987 n = 129 ~ ANTLERLESS DEER 1988 n = 12 40 ~ l- I C!J 30 UJ ~ >- o a co 20 10 o o 1 234 5 6 7-15 AGE (YEARS) Fig. 13. Average eviscerated body weights for antlerless elk (TOP) and deer (BOnOM) on the Forbes-Trinchera Ranch. Male and female young pooled for age class o. �JOB PROGRESS REPORT State of Colorado Project No. W-lS3-R-2 Mammals Research Work Plan No. 3 Elk Investigations Job No. 7 Elk Census Methodology Period Covered: Author: Personnel: July 1, 1988 - June 30, 1989 D.J. Freddy G. White, L. Carpenter, R. Bartmann ABSTRACT Line transects and quadrats were not flown because heavy snowfall severely concentrated elk and deer. Line transects and quadrats will be flown in December-January 1989-90. A brief description of methods to be used is included for reference. ��63 JOB PROGRESS REPORT ELK CENSUS METHODOLOGY David J. Freddy P.N. OBJECTIVE Evaluate methods to estimate numbers of elk during winter. SEGMENT OBJECTIVES 1. Determine efficacy of line transect census methodology of elk and deer on winter ranges shared by both species. to estimate numbers 2. Compare estimates of deer density based on line transects and quadrats (existing census system) in an area where both methods can be employed. STUDY AREA The Troublesome portion between Highway 125 and selected for evaluating estimate numbers of elk numbers of elk and deer efficiently sampled. of Game Management Unit (GMU) 18 within Middle Park, Troublesome Creek and north of the Colorado River, was aerial line transects (Burnham et al. 1980) to and deer during winter. This area has significant residing in a relatively small area that can be METHODS AND MATERIALS The sampled area was limited to those areas inhabited by elk and deer during January and February. Deer winter range in the Troublesome area for this time period was previously defined by Gill (1969) and encompassed l66km2 (64mi~ of sagebrush habitat. Elk winter range was based on distribution of elk as observed during sex and age classification surveys done in January and February in recent years (pers. comm. B. Thompson, R. Firth) and encompassed 246km2 (95mi~ of sagebrush, aspen, aspen-conifer, and heavy conifer habitats. In general, deer winter range occurred from 2257-2685m (7400-8800ft) and elk winter range included the deer winter range and areas to 2990m (9800ft.) in elevation. The 2 defined winter ranges were outlined on 1:24000 topographic maps. Two sets of line transects each containing 26 transects were selected and marked on topographic maps. Initial starting points for sets of transects were 500m apart. Transects within each set were systematically spaced at 1000m intervals, oriented on true north bearings, and were l-15km long. Each set of transects simultaneously sampled the defined elk and deer winter ranges. Beginning points of transects were not marked with flight markers. �64 We expected to encounter 130 and 150 groups of elk and deer, respectively, if each set of line transects were flown twice (Freddy 1988). This number of groups would allow reasonable evaluation of sighting curve functions and provide expected coefficients of variation of + 15% about mean densities of elk and deer (White et al. 1989 In press). We wanted to compare estimates of deer densities based on line transects and quadrats. Deer densities in Middle Park have been estimated since 1968 using a stratified sampling system that employs the 2.6km2 (lmi~ quadrat as the sampling unit (Gill 1969). The Troublesome strata coincides with the area sampled by line transects. In addition to the 10 existing quadrats in the Troublesome, 20 additional quadrats were selected at random and marked on topographic maps. These 30 quadrats and the line transects sampled the same 166km2of deer winter range in the Troublesome area. Key corners of all quadrats were marked on the ground with orange markers to aid in navigating to quadrats. We calculated that a difference in deer densities between transects and quadrats of 50% or more could be detected with 95% confidence if we flew 30 quadrats. These calculations were based on variances about average densities of deer (10/km~26/mi~ measured on 10 quadrats in the Troublesome in 12 previous years. We also assumed a sightabi1ity of 60% for deer on quadrats (Bartmann et a1. 1986) and observation of 150 groups of deer on transects. Quadrats were to be flown once. All flights were to be done using a Bell-Soloy helicopter. A navigator and observer, in addition to the pilot, were responsible for observing elk and deer. The observer seated on the right estimated perpendicular distances to and counted those groups of elk or deer located from the transect center line to the right. The middle observer (navigator) estimated perpendicular distances to and counted only elk to the left of the transect center line. Markers placed at known distances from a practice transect line were used by observers to practice estimating perpendicular distances prior to flying each day. Transects and quadrats were to be flown within a 3-day period. Both sets of transects were to be flown on both the first and third days with sets of transects randomly selected to be flown in either the morning or afternoon. Quadrats were to be flown throughout the second day. RESULTS AND DISCUSSION Line transects and quadrats were not flown because heavy snowfalls in late January and early February severely concentrated elk and deer just prior to the scheduled timing of the census. One major storm left 75cm (30in) of snow on portions of the winter range. Many elk concentrated around haystacks or in feed yards of domestic cattle. Censusing animals under these conditions would have resulted in undue harassment of elk, deer, and domestic cattle, damage to private property, and poor estimates of animal densities. Extreme conditions persisted until the end of March. Line transects and quadrats will be flown in late December or early January of 1989-90. �6.5 LITERATURE CITED Bartmann, R.M., L.H. Carpenter, R.A. Garrot, and D.C. Bowden. 1986. Accuracy of helicopter counts of mule deer in pinyon-juniper woodland. Wildl. Soc. Bull. 14:356-363. Burnham, K.P., D.R. Anderson, and J.L. Laake. 1980. Estimation of density from line transect sampling of biological populations. Wildl. Mono. 72. 202pp. Freddy, D.J. 1988. Elk census methodology. July (1):78-82. Colo. Div. Wildl. Game Res. Rep. Gill, R.B. 1969. A quadrat count system for estimating game population. Colo. Game, Fish, & Parks Game Info. Leaflet 76. 2pp. Gill, R.B. 1969. Middle Park deer study population density and structure. Colo. Game, Fish, & Parks Game Res. Rep. July (1):106-122. White, G.C., R.M. Bartmann, L.H. Carpenter, and R.A. Garrot. Evaluation of aerial line transects for estimating mule deer densities. J. Wildl. Manage. 53(3): In press. 7 - /; ./~/-//1 Prepared by .a(~.~/_·Z~-~i_~d_·_·~~~.JI-+ ~~~c~~~:IL~;"/_L~~~ David J .•Freddy 7 Wildlife Researcher _ �� https://cpw.cvlcollections.org/files/original/6c11c8f2c0318d707b31e9287f89ce18.pdf cb2dc74a27f04d7fe6153f2ca220a149 PDF Text Text 67 Colorado Division Wildlife Research July 1989 of Wildlife Report JOB PROGRESS REPORT State of Colorado Project No. ~W_-~1~5~3_-~R~-~3 _ Mammals Research Work Plan No. _ Multispecies ~l~A~ Job. No. 1 Period Covered: Author: Wild Ruminant Dynamics Investigations Forage Selection July 1, 1988 - June 30, 1989 P. H. Neil Personnel: M. W. Miller, R. B. Gill, M. L. Stevens, D. L. Baker, K. A. Trust, K. A. Sheehan, B. J. Maynard, M. A. Wild, H. J. Lucking, and T. Ritchie ABSTRACT Eight pronghorn fawns were successfully raised and are being used in controlled experiments to test the light wavelength perception range of pronghorn. Facility repairs continued, and 3 shelters in the bighorn sheep pens were rebuilt and 1 shelter in the elk pens. An additional section of alleyway was constructed to accommodate a portable squeeze chute for elk. All animals at the facility are presently healthy. ��69 ANIMAL AND PEN SUPPORT FACILITIES FOR MAMMALS RESEARCH Paul H. Neil P. N. OBJECTIVES Provide and maintain populations of captive animals and pen facilities support Mammal and Avian Research Programs. AGREEMENT to OBJECTIVES 1. Maintain and improve animal research 2. Coordinate 3. Maintain up to 15 elk, 30 mountain sheep, 30 pronghorn antelope, 15 mule deer, and 11 domestic cows in suitable health to perform required research experiments. 4. Conduct management experiments efficiency and efficacy. all rearing, facilties. training, maintenance, and research activities. to increase feeding and maintenance METHODS AND MATERIALS Routine neonate rearing procedures were used to hand rear 8 pronghorn. Eight bighorn sheep lambs were born at the facility and left on the ewes to raise. Daily contact was made with the animals to enhance tameness and, in most cases, seems to be a satisfactory procedure for our needs. Three shelters were rebuilt in the bighorn sheep pens using a different design to cut down on wind damage and animal damage. RESULTS AND DISCUSSION Eight pronghorn antelope are being used in controlled experiments to test the light wavelength perception range of pronghorn, specifically to test for visual perception in the region of near infrared wavelengths. Details of progress in this experiment are described under WPlA,J4. The 11 elk that were used in the elk-cattle competition study returned to the facility in good shape. Details of their use are described under WP9A,Jl and WP3,J5. Expansion of the pronghorn pens began during the fiscal year and is near completion. This project will relieve some pressure on our existing pens. �70 All animals at the facility are presently healthy. The big game research herd presently consists of 11 elk, 31 bighorn sheep, 1 Rocky Mountain goat, 11 domestic cows, and 23 pronghorn antelope. Prepared by \~A \~ ;_._~C i IA.' __ ~~ Paul H. Neil Wildlife Research Tech III _ �71 Colorado Division of Wildlife Wildlife Research Report July 1989 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~ Project No. _ W-lS3-R-3 Mammals Research Work Plan No. __~l~A~ _ Multispecies Job No. __~ __-=3 _ Mammals Research Period Covered: Investigations 2 Administration July 1, 1988 - June 30, 1989 Author(s): R.B. Gill Personnel: L. Lovett, N. McEwen ABSTRACT All administrative objectives listed in the Segment Narrative for Mammals Research 2 for FY 1987-88 were accomplished. In addition a draft River Otter Recovery Plan and a draft Black Bear Management Plan were prepared and submitted for review. ��73 MAMMALS RESEARCH 2 ADMINISTRATION R. Bruce Gill P.N. OBJECTIVE Administer research within productivity at the lowest the Mammals cost. SEGMENT Research 2 Unit for the highest OBJECTIVES 1. Require candidate research research project selection funding. 2. Require all research study plans to be peer reviewed, reviewed and approved by the Research Leader before the research is initiated. 3. Require quarterly research study. 4. Subject all research projects to periodic review Division's formal administrative review process. 5. Allocate fiscal resources and track expenditures of each research to assure fiscal responsibility and accountability. 6. Maintain a manual on current standard administrative operating procedures and distribute to each Wildlife Researcher. 7. Develop, implement, and maintain an effective information transfer process that assures research results are disseminated to appropriate information users in a form that maximizes the probability that the information will be used. progress projects to go through the Division's process before they are considered for reports RESULTS and annual progress reports according of each to the study AND DISCUSSION Objective 1. A draft river otter recovery plan and draft black bear management plan were prepared. These plans will be used as the basis for selecting research on the 2 species. Objective 2. disease Planning was begun on a study to evaluate the role of in the ecology and management of mountain sheep. Objective 3. Quarterly reports were received and reviewed for each Mammals Research 2 study active during FY 88-89. Annual Job Progress Reports were prepared and submitted to the Federal Aid planner by the September 15 deadline. Objective 4. Mountain sheep, pronghorn, river otter, and elk/cattle grazing studies were reviewed in the field during the Segment. Field work has ended for the mountain lion study so it was not reviewed. Objective 5. The resource allocation to the Mammals Research 2 cost �74 center for FY 88-89 was further allocated to each Wildlife Researcher for each research study. These individual study allocations were prepared in Segment Narrative format and submitted to Federal Aid Division of the U.S. Fish and Wildlife Service for approval and P-R funding. Budget status reports were prepared quarterly for each Wildlife Researcher. A final budget status report issued 7/24/89 indicated that the Mammals Research 2 Section expended 100.1% of the $576,114 allocated for FY 88-89. Objective 6. updated The Standard Administrative Operating at least quarterly during the segment. Procedures manual was Objective 7. An adaptive assessment simulation model was developed during the segment to assist DOW in developing plans to co-manage sympatric populations of mountain sheep and mountain goats. The model integrated published literature on mountain sheep and mountain goat ecology and quantified "best guess" scenarios where experimental data were lacking. This model is being prepared for publication. It has been reviewed several times with DOW field personnel. The Black Bear Management Plan is now in it 4th draft version and incorporates the results of Colorado's black bear research study with those of other bear studies to identify critical management issues and strategies. This plan was reviewed and incorporated revisions from DOW personnel and nearly all public groups which expressed an interest in citizen participation in the black bear planning process. Prepared bY:_~__'_'_~~\;.J...--) R. Bruce Gill Wildlife Research ~_ Leader �75 Colorado Division of Wildlife Wildlife Research Report July 1989 JOB PROGRESS REPORT State of Colorado Project No. Work Plan No. ~l~A~ Job. No. 4 Period Covered: Authors: Personnel: Mammals Research W-1S3-R-3 _ Multispecies Investigations Wild Ruminant Forage Selection Dynamics July 1, 1988 - June 30, 1989 B.J. Maynard P.N. Lehner, M. Miller, S. Roberts, R.B. Gill ABSTRACT Much of the'Segment was spent training pronghorn to respond consistently to white light stimuli in a nonrandom fashion. Trial and error modifications were made in light source, brightness, and food reward. Additional improvements were made in training/conditioning protocol to sharpen the ability to detect differences in pronghorn light wavelength percepcion. Initial physiological tests (electroretinograms) were scheduled to determine pronghorn light wavelength recepcion at the retina. ��77 'WILD RUMINANT FORAGE SELECTION DYNAMICS B.J. Maynard P.N. OBJECTIVE To evaluate the role of color vision foraging ruminant--the pronghorn. in diet selection SEGMENT a detailed of a small, selectively OBJECTIVES 1. Prepare Program Narrative. 2. Foster-rear 3. Conduct controlled experiments to test the light wavelength perception range of pronghorn, specifically to test for visual perception in the region of visual and near infrared wavelengths (ca 500->700 nm) or (ca 500-800 nm). up to 8 pronghorn fawns to use in research studies. METHODS Eight hand-reared pronghorn were maintained at the Colorado Division of Wildlife's Foothills Wildlife Research Facility (FWRF) on a diet of alfalfa hay, pellets, water, and mineralized salt, fed ad libiLum. Pronghorn were weighed weekly to monitor overall health and growth performance (Fig. 1). All animals appeared to grow normally and were maintained in good health throughout the segment. Wavelength discrimination trials were continued throughout the segment (See Appendix A for specific discrimination trial methodology). For each trial, individual pronghorn were led into the start box of a Y-maze and required to choose between a "light on" branch and a "light off" branch. The "light on" branch held a food reward within a goal box at the end of the branch; the "light off" branch" did not offer a food reward. The intention is for pronghorn to learn the light/food association and to enter the "light on" branch significantly more often than one would expect if choices were made at random. Once pronghorn have learned to consistently discriminate "light on" from "light off", training will be extended to wavelengths of narrow color bandwidths. These trials will evaluate which wavelength bands pronghorn perceive. More importantly, once the protocol is established and pronghorn have learned to make light-related choices in the maze, the nature of the stimuli can be adapted to generate behaviorally a spectral sensitivity curve for the pronghorn visual system. This information will be fundamental to unraveling the role vision plays in pronghorn diet selection. �78 PRONGHORN GROWTH RATES 1988-1989 WEIGHT (KG) 50 r-----------------------------------------~ 45 40 ----- -----------.-----.-------.-.---------.---.. ---.-- - ---.-----.--------.. -.------.. 30 25 20 15 10 5 0 0 10 Summer 1988 Fig. 1. Pronghorn 20 30 40 WEEKS FROtl BIRTH growth rates, summer 1988-summer 50 Summer 1989 1989. RESULTS In July an analysis of Y-maze trial data revealed no discernable pattern to the choices pronghorn were making in the maze. There was no indication that the animals were learning the light/food association nor was there any recognizable pattern or strategy to their choices. At this time several changes were made to increase both light saliency and subject motivation. A light stimulus not obvious to a subject in the maze could inhibit learning of the light/food association. Through July 1989, the light sources had been high intensity lamps which shone directly through one-inch diameter holes in the end wall of each maze branch. In July the diameters were changed to 3 inches, and white plexiglass "screens" were inserted in front of the lamps. The high intensity lamps were extremely bright to the human eye, to the point of being mildly painful if the line of sight was directly into the beam of the light. The plexiglass decreased the brightness of the lamps so that they were still readily visible to a human subject, but not at all painful, and so �79 should have eliminated any possibility that the brightness of the lights was in fact aversive to the pronghorn. Also in an attempt to increase light saliency, the light was flashed while the pronghorn were in the start box. In order to further enhance the light/food association, several more changes in protocol are necessary. Currently, the lights in each branch of the maze are 32 inches above the food trays, which are recessed into feed boxes. Lights will be lowered to 12 inches above the food trays, facilitating the association between light and food. In addition to inadequate stimulus saliency, inadequate motivation of the animals to "solve" the problem could have led to poor performance. The animals were fed hay and pellets ad libi~um throughout the day and were rewarded with raisins and marshmallows in the maze. Cafeteria trials run during Summer 1988 indicated that these 2 foods were the best rewards for pronghorn. In July 1989, more cafeteria trials, offering sugar cubes, fruit drink, and gummy bears, were run in an attempt to find a better reward. The decision to offer these foods was based on their similarity to the chewy consistency and the sweetness of raisins and marshmallows. No food was found that the animals would ingest as frequently and rapidly as the marshmallows, raisins, and hay and pellets. Another procedure used in operant conditioning research to enhance stimulus/reward (light/food) associations classically is first to condition the pronghorn to associate light with food. The animals are placed in an enclosed area and presented light numerous times just prior to food presentation. Thus, the light signals food arrival and pronghorn should soon cue light with food. If the other changes made to enhance light saliency do not result in pronghorn responding to the light, then this procedure will be carried out. Paired with the behavioral research of pronghorn light percep~ion by the brain, are physiological tests to determine pronghorn recep~ion of light by the retina. An electroretinogram (ERG) will be conducted at the Colorado State University Veterinary Teaching Hospital on August 8. Dr. Steve Roberts (D.V.M.) will conduct the ERG and Dr. Mike Miller (D.V.M.) and Margaret Wild will administer anesthesia. Data obtained from this and future ERGs will be. combined to generate a spectral sensitivity curve for the pronghorn retina. Prepared by ��81 Appendix A Pronghorn Reception and Perception of Visible and Infrared Light Study Plan Revised July 1, 1989 Barbara J. Maynard A. NEED Pronghorn(Antilocapra americana) inhabit the semi-arid grasslands of North America, where precipitation is low ( < 25 cm annually; Beale and Smith, 1970; Boyle, 1981). In this environment, water might be a limiting resource of pronghorn populations. Indeed, Beale and Smith(1970) correlated pronghorn fitness(number and health of offspring) with water availability. In addition, water consumption from troughs decreased as forage succulence and temperature increased. As forb (a primary diet ingredient) succulence and volume decreased, pronghorn switched to the most succulent forage available. Beale and Smith offer no evidence that these relationships are causative rather than correlative; however, the indication is that water is an important limiting resource for pronghorn. Based on pronghorns' relatively small size and high metabolic rate, quality and digestibility of forage also should be important factors in pronghorn diet (Boyle, 1981). Krueger (1986) found that pronghorn foraged in areas where forbs and shrubs had higher nitrogen content than other areas. Likewise, Schwartz, et al. (1977) found that pronghorn were more selective grazers than sheep, bison, and cattle. Pronghorn ate forage of higher crude protein and lower fiber content than did the other three species. Numerous studies similar to those mentioned above have documented that pronghorn are selective foragers; how pronghorn select their food, however, is not known. Visible and infrared reflectances by plants provide a reliable index of plant succulence and productivity(discussed below). The present study is designed to investigate the capabilities of the pronghorn visual system in the visible and infrared spectra. Vegetation differentially reflects incident electromagnetic radiation in the visual and infrared spectra based on different plant qualities. Below 400 nanometers (nm) and above 2700nm, leaf reflectances are generally less than five percent of incident light and are fairly uniform (Knipling, 1970). Within this 400--2700nm range, however, reflectances vary from plant to plant and reveal features of plant quality. Water content is responsible for absorption of radiation in the mid-infrared range, 1300--2400nm. That is, plants with higher water content absorb more mid-infrared radiation than do plants with lower water content (Knipling, 1970; Hunt, et aI., 1987). Reflectance in wavelengths other than the mid-infrared band can also provide information about plant quality. Plots treated with different levels of nitrogen fertilizer can be distinguished in the red(640--660nm) and near-infrared(820--830nm), as well as midinfrared, bands (Everitt, et aI., 1987). Fertilized plots reflect a higher percentage of red and near-infrared radiation and absorb a higher percentage of mid-infrared than do unfertilized �82 plots. The different red and near-infrared reflectances can be attributed to higher productivity resulting in higher chlorophyll content. The mid-infrared reflectivities can again be attributed to higher water content, as a result of higher productivity (Everitt, et aI., 1987, 1986). The presence of visual pigments sensitive to long wavelengths has been demonstrated in some vertebrates including the freshwater fish, the rudd (Scardinius erythrophthalmus, 620nm, Loew & Lythgoe, 1978) and the goldfish (Carassius auratus, 625nm, Harosi & MacNichol, 1974). Color vision has been demonstrated in mammals such as giraffes, pigmy goats, red deer cows, and domestic goats, (Backhaus, 1959b; Backhaus, 1959a; Buchenauer & Fritsh, 1980). Pronghorn visual capabilities, however, are not well enough studied to understand their role in pronghorn forage selection. B. EXPECTED RESULTS AND BENEFITS This study will provide an understanding of pronghorn visual capabilities in the infrared and visual spectra, which will then generate further hypotheses and research into pronghorn foraging strategies. C. OBJECTIVE To determine radiation. the extent of pronghorn reception and perception of visual and infrared D.APPROACH Subjects Five female and three male pronghorn, born in June 1988, were bottle-raised at the Foothills Wildlife Research Station in preparation for this study. Five of the animals were captive-born; two were wild-caught; and one was found as an orphan. Apparatus Y-Maze: A T-high, wooden Y-maze has been constructed in the pronghorns' pen. The buzzer, the starting gate, and the two exit gates can all be controlled by an experimenter behind the start box. The T-shaped start gate, which raises and lowers in a channel iron track, is of wire mesh so that subjects can see through it, but not pass it. A video camera mounted above the maze gives a view from the start gate to slightly beyond each "choice" line. These "branch" and "choice" lines are wooden slats painted white and buried to ground level. The top of the maze is eighty percent covered by plywood, which prevents most, but not all, incident sunlight from shining into the maze. A three-sided "sun shield" will surround the light stimulus in each branch in order to prevent sunlight from directly interfering with the stimuli. The areas inside these shields will be painted flat black in order to accentuate the stimuli and to reduce reflections. Light Sources and Filters: High intensity tungsten light sources(Central Scientific Company, Franklin Park, IL, model no. 85262-01} will be mounted on top of the feed boxes behind the end wall of each branch of the maze and enclosed in black plexiglass boxes. Tungsten bulbs were selected for their high radiation in longer wavelengths (Riggs, 1966a). All filters will be 1"-diameter glass. Narrow bandpass filters with bandwidths of 10nm �83 and central wavelengths of 500, 550, 600, and 650nm will selectively transmit light of narrow wavelength bands. A long wave pass filter with cut-on wavelength (50% transmission) of 700nm will transmit radiation of wavelength longer than 700nm and will block radiation of wavelength less than 700nm. Procedure This study involves two phases: (1) electrophysiological tests (electroretinography) will determine reception of visual and infrared light wavelengths by the retina; and (2) discrimination trials will test perception of visual and infrared light wavelengths by the brain. Because the electrophysiological work involves anesthetization, which always carries with it a certain risk to the animals, the behavioral trials will be completed first. Discrimination Trials: Training & Trials: In order to accustom the pronghorn to the Y-maze, they were fed within this enclosure throughout bottle-feeding (Summer 1988). Fawns were led through the maze to the end of a branch, where they received the bottle. As the fawns began to take an interest in solid food, they were trained to eat marshmallows from the two feed boxes at the ends of the branches. Throughout all trials, a light-on cue will function as the SD+, light-off as the SD-. The two branches will be identical excepting the light source turned on in one branch, and off in the other. Subjects will be led into the start box with the start gate down. The buzzer, acting as a warning cue, will sound for 3 seconds. Ten seconds after the buzzer ceases, the gate will lift, and the subject will be allowed to make a choice. A subject's entire body must completely pass the choice line in order to constitute a choice. At this point, an experimenter observing the trial via video will lower the gate, retaining the animal in the chosen branch. The feed box associated with the SD+ will contain 10 miniature marshmallows in a metal tray available to the subject in the corresponding branch. The SD--associated branch will also contain 10 marshmallows, but this tray will be covered by a screen, preventing the subject in this branch from receiving the reward. A lip of the food box keeps the trays, screens, and marshmallows hidden from the subject until a choice has been made. Following a "correct" (SD+) choice, the subject will be released from the maze immediately after the choice(Le., crossing the choice line), but will be allowed to re-enter the branch to eat the reward. In the event of an "incorrect" (SD-) choice, the subject will be held in the maze 60 seconds; the extra time will act as a punishment. Light stimuli will be extinguished when the subject begins to feed. The pronghorn will be subjected to a correction procedure during trials. If a subject makes an incorrect choice, that subject will immediately repeat the same trial until a correct choice is made. Only the original incorrect choice will be considered a trial result. If a subject does not choose the SD+ after 4 attempts, then the subject will be led through the maze to the correct branch and allowed to take the reward. Subjects will undergo one or more trials daily. Assignments of stimuli to branches will be based on a random numbers table and will be done independently for each animal. A branch may be associated with the SD+ no more than three consecutive trials for any animal. Correct vs. incorrect trials will be assessed by the experimenter recording from the video monitor at the time of the trials. Number of crosses of each "branch" line before decision, as well as time from gate raising to choice will be assessed by the experimenter at a later date from video recordings of the trials. The criterion for a branch line cross is the same as for a choice; the entire body must cross the line. In order to avoid experimenter bias, an observer naive to the correct branch will periodically check the experimenter's results on all aspects of data collection. �84 Trials will begin with an SD + of white light. After this discrimination has been established, a narrow bandpass filter with central wavelength of 500nm will be placed in front of each light source. As before, only one light source will be turned on for each trial. This 500nm vs. no light discrimination will be followed by 550nm vs. no light, 600nm vs. no light, 650nm vs. no light, and finally by infrared vs. no light discriminations. If pronghorn are capable of seeing in the infrared range, they will be able to make this last discrimination. If the discrimination is made, then narrow bandpass filters in the infrared range will be used to determine which wavelengths in the infrared spectrum pronghorn are able to perceive. Over 20 trials, a performance level of 75% correct significantly differs from a level of 50% correct expected by chance (p = 0.05, Bruning & Kintz, 1987). Each subject will be required to demonstrate this 75% level correct over the subject's last 20 trials before advancing to the next wavelength. Data Analysis: Attainment of the 75% level correct criterion will demonstrate a subject's ability to discriminate a given wavelength. Electroretinography: Electroretinography (ERG) generates a graph of retinal potential over time (Riggs, 1966b). Light of a known wavelength and intensity is directed at the subject's eye and the elicited potential is measured. In this study, ERG will determine reception by the pronghorn eye of different wavelengths of light under both scotopic(dark-adapted) and photopic(light-adapted) conditions. This procedure will produce data for a graph of stimulus intensity required to produce a retinal potential of given amplitude versus wavelength of stimulus. This graph will show spectral sensitivity of the pronghorn retina. ERG data will also be analyzed for the presence of the scotopic and photopic waves in order to establish the presence or absence of rods and cones in the pronghorn retina. Electroretinography will be performed under the direction of Steve Roberts, D.V.M. and Mike Miller, D.V.M. The pronghorn will be transported to the Colorado State University Veterinary Teaching Hospital, via horse trailer, where they will be anesthetized before undergoing the procedure. A detailed protocol for transportation and handling of the animals will be established beforehand using three castrated pronghorn. E.SCHEDULE November 1988-January December 1988-December 1989 1989 Train castrated pronghorn to enter horse trailer. Discrimination trials. January 1989 Establish ERG procedure. January 1990 ERG on 8 pronghorn. February March 1990 1990-May Data analysis. 1990 Thesis. May 1990 Completion of coursework. August 1990 Graduation. �85 F. LITERATURE CITED Backhaus, V.D.(1959a). Experimentelle Untersuchungen uber die Sehscharfe und das Farbsehen einiger Huftiere. Z. Tierpsychologie, 16:445-467. ____ ~.(1959b). Giraffe(Giraffa 16 :468-477. Experimentelle Prufung des Farbsehvermogens einer Massaicamelopardalis tippelskirchi Matschie 1898). Z. Tierpsychologie, Beale, D.M., & A.D. Smith(1970). Forage use, water consumption and productivity of pronghorn antelope in western Utah. J. Wildl. Manage., 34(3):570-582. Boyle, S.A.(1981). Summer habitat of pronghorn in the Red Desert of Wyoming. M.S., Dept. of Fishery & Wildlife Bio., Colorado State University. Bruning, J.L. & B.L. Kintz(1987). Computational Foresman, & Co., Glenview, IL. Handbook of Statistics, third edition. Scott, Buchenauer, V.D. & B. Fritsh(1980). Zum Farbsehvermogen von Hausziegen(Capra Z. Tierpsychologie, 53:225-230. hircus L.). Everitt, J.H ..• D.E. Escobar, C.H. Blazquez, M.A. Hussey, & P.R. Nixon(1986). Evaluation of the mid-infrared(1.45-2.0 m) with a black-and-white infrared video camera. Photogram. Eng. & Rem. Sens., 52:1655-1660. _________ , M.A. Alaniz, & M.R. Davis(1987). Using airborne middleinfrared(1.45-2.0 m) video imagery for distinguishing plant species and soil conditions. Rem. Sens. of Environ, 22:423-428. Harosi, F.I. & E.F. MacNichol, Jr.(1974). Visual pigments of goldfish cones, spectral properties and dichroism. J. of Gen. Physiology, 63:279-304. Hunt, Jr., E.R., B.N. Rock, & P.S. Nobel(1987). Measurement of leaf relative water content by infrared reflectance. Rem. Sens. of Environ, 22:429-435. Knipling, E.B.(1970). Physical & physiological basis for the reflectance of visible and nearinfrared radiation from vegetation. Rem Sens of Environ, 1(3) :155-159. Krueger, K.(1986). Feeding relationships among bison, pronghorn, and prairie dogs:an experimental analysis. Ecology, 67(3):760-770. Loew, E.R. & J.N. Lythgoe(1978). The ecology of cone pigments in teleost fishes. Vision Res., 18:715-722. Riggs, L.A.(1966a). Light as a stimulus for vision, pp. 1-38. In Vision & Visual Perception, C.H. Graham(ed.). John Wiley & Sons, Inc., New York. Riggs, L.A.(1966b). Electrophsiology of vision, pp. 81-131. In Vision & Visual Perception, C.H. Graham(ed.). John Wiley & Sons, Inc., New York. �86 Schwartz, C.G., J.G. Nagy, & R.W. Rice(1977). Pronghorn dietary quality relative to forage availability and other ruminants in Colorado. J. Wildl. Manage., 41 (2):161-168. �87 Colorado Division Wildlife Research July 1989 of Wildlife Report JOB PROGRESS REPORT State of Colorado Project No. -=W_-~1~5~3_-~R~-~2 _ Mammals Research Work Plan No. __~l~A~ _ Multispecies Investigations Consulting Services for Mark-Recapture Analysis Job No. 5 Period Covered: Author: July 1, 1988 - June 30, 1989 G. C. White Personnel: L. H. Carpenter, T. D. 1. Beck R. B. Gill, R. M. Bartmann, G. D. Bear, ABSTRACT Progress toward the objectives of this job includes: 1. A manuscript summarizing the results of the Piceance Basin deer population studies has been developed, with publication intended as a Wildlife Monograph of The Wildlife Society. 2. A study of compensatory effects of harvest on the Piceance Basin mule deer population has been designed, with the first experimental harvest in December, 1989. Radio collars will be placed on fawns during November, 1989 to monitor over-winter survival of the animals. 3. A Monte Carlo simulation study to evaluate mark-resighting methods to estimate mountain sheep numbers is ongoing, with a final report expected by December, 1989. 4. Consultation has been provided in the design and analysis of an experimental isotope mark-recapture study to estimate river otter popUlation size. 5. A manuscript has been published in the July, 1989 issue of Journal of Wildlife Management on an evaluation of line transect methods for estimating mule deer density. 6. A manuscript will appear in the October, 1989 issue of Journal Wildlife Management on an evaluation of capture-resighting methods for estimating population size of elk. 7. A model of a Colorado black bear population has been developed and used to simulate various experimental harvest strategies. of ��89 CONSULTING SERVICES FOR MARK-RECAPTURE ANALYSES G. C. White P. N. OBJECTIVES Model and simulate population estimates of deer, elk, mountain mountain goats with mark-recapture methods. sheep, and SEGMENT OBJECTIVES 1. Evaluate various experimental harvest strategies for a Colorado bear population using a Monte Carlo simulation model. black RESULTS AND DISCUSSION A Monte Carlo computer simulation model has been developed of a Colorado black bear population using the Statistical Analysis System (SAS 1985). It is a stochastic model patterned after the grizzly bear model of Knight and Eberhardt (1985). The structure of the model is appropriate for Colorado black bears, with parameter estimates taken from the work in southwestern Colorado of T. D. I. Beck. The stochasticity in the model is of the form of binomial processes for births and deaths. Thus, for a 90% survival rate, the model does not multiply the current population size by 0.9. Rather, th~ N animals in the population are each assigned a fate (lived or died) according to the probability 0.9. The RANBIN function of SAS is used to perform this process. The structure of the model is based on 3 arrays. The array subadlt{O:l} holds the number of cubs and yearlings of both sexes without mothers. The array males{2:20} holds the number of males of ages 2 to 20 (the maximum age attainable). The array fem{2:20, O:6} holds the number of females of ages 2 to 20, and also their reproductive status. Category o means no cubs or yearlings, 1 means 1 cub, 2 means 2 cubs, 3 means 3 cubs, 4 means 1 yearling, 5 means 2 yearlings, and 6 means 3 yearlings. Although the yearlings are not actually with the mother, the mother is not allowed to breed in 2 consecutive years (unless the cubs are lost). Thus categories 4-6 provide a mechanism to store females for one year until they are ready to breed again. Two major extensions were made to the grizzly bear model developed by Knight and Eberhardt (1985). First, Beck (Pers. Comm.) has shown that survival of cubs and yearlings and reproductive rates are affected by the berry crop. Late spring frosts curtail mast and berry production. Therefore, 2 sets of values for these parameters were included in the model depending on whether the current year was a "good" berry crop or a "bad" berry crop. Bad berry crops occurred at random with a frequency of 1 year out of 10. Second, the model included various harvest strategies. A major consideration of the various experimental harvests was the proportion of males versus females in the harvest. Because of the differential survival of males and females, a straight percentage of the population �90 would have about 78% females. Therefore, all the experimental harvests were set up to take 10% of the adult population, but with differential vulnerability of females and males. A harvest vulnerability factor was developed to change the proportion of females depending on the time of year. For example, an early spring harvest might have only 30% females in the harvest. To obtain this level of harvest, only about a 3.3% harvest of the females would be needed. A female vulnerability factor of 0.25 was used to obtain the 3.3% (=[O.25/{1-0.25}]*0.1) harvest of adult females and a 30% (=[{1-0.25)/0.25]*0.1) harvest of males. The vulnerability factor was juggled to obtain values that generated appropriate sex ratios in the harvest. The cubs of any females harvested in a spring season (April-June) are all assumed to die, whereas cubs of females harvested in the fall (September-October) are assumed to survive at the rate of cubs without mothers. In addition, an increase in vulnerability to harvest of the entire population was included in the model. On average, 1 year out of 10 had a double success rate (20% harvest instead of 10%). This doubling of the harvest was included in the model to represent the effects of variable weather on harvest observed by Beck (Pers. Comm.) The following parameter values were used in the simulations. Survival Rates Age Class Females Good and Bad Berry Crops Adults, > 4 years old 0.71 0.52 4-year olds 0.52 3-year olds 0.52 2-year olds Yearlings (with mother) 0.90 0.90 Yearlings (without mother) 0.92 0.90 0.90 0.90 0.90 0.90 Good Berry Crops Cubs (with mother) Cubs (without mother) 0.57 0.57 0.57 0.57 Bad Berry Crops Cubs (with mother) Cubs (without mother) 0.33 0.33 0.33 0.33 Reproductive Parameter Parameters Definition (Barren means cubs born more than 1 year ago) Prop. of barren 2 year olds having cubs Prop. of barren 3 year olds having cubs Prop. of barren 4 year olds having cubs Prop. of barren 5 year olds having cubs Prop. of barren 6+ year olds having cubs Good Berry Years 0.00 0.25 0.33 0.50 0.80 Bad Berry Years 0.00 0.00 0.00 0.00 0.20 �91 Prop. of litters with 1 cub Prop. of litters with 2 cubs Prop. of litters with 3 cubs 0.19 0.59 0.22 0.19 0.59 0.22 Sex ratio at time of 2nd birthday 0.50 0.50 In addition to the above effects from bad berry years, all cubs born during bad years had reproductive rates as if it were a bad year until they were 6 years old. After a bad berry year, all barren adults had 0.90 reproduction instead of 0.80, a compensation for the previous bad year (unless the second year was also a bad berry year). The initial population sizes were constructed by making 5 runs of the model for 30 years with no harvest, and using the resulting population means for the various age and sex classes. The exact values for each of the age and sex classes are initialized the same in each simulation. A summary of these initial conditions are: Age and Sex Class Cubs (both sexes) Yearlings (both sexes) Adult Males Adult Females Total Population Size 197 93 80 296 666 Thus, these initial conditions repr~sent a fairly large population, approximately 5-10% of the state-wide population. This size of bear population is equivalent to the population of a major black bear Data Analysis Unit (DAU). Six harvest regimes were simulated: (1) no harvest; (2) an early spring season, with the expected harvest consisting of 30% females; (3) a later (or longer) spring season with the expected harvest consisting of 35% females; (4) a fall season with the expected harvest consisting of 45% females, (5) a fall harvest with the expected harvest consisting of 40% females, and (6) a fall harvest with the expected harvest consisting of 35% females. The difference between an early and late spring season is just the value of the selection factor, and similarly for the 3 fall seasons. The difference between the spring and fall seasons is the value of the selection factor and also that cubs survival is not zero for cubs of females that are harvested. All simulations were performed for 30 years, i.e., the population was projected forward for 30 years. This process was replicated 100 times to provide a mean and standard deviation for each of the parameters measured on the simulated population. Figure 1 provides a summary of the annual rate of increase for the simulations with constant survival and reproduction, berry crop failures, heavy harvest, and both berry crop failures and heavy harvest. Only the fall season with 45% females in the harvest is included. The effect of berry crop failures on the model population was to increase the variability of population size after 30 years and to �92 Expected Annual Population Increase (%) 5 4 3 2 1 o None D Early Spring Late Spring Fall Harvest System Constant Survival and Berry Cropp Reproduction Failures Heavy Both Berry Crop Harvest Fail. and Heavy Hrv. Figure 1. Annual rate of increase (percent) for simulations with constant parameters, berry crop failures, double the normal harvest rate, and a combination of berry crop failures and double the normal harvest. slightly change the expected population size. The impact of good and bad berry crops seems to affect the populations harvested in the spring more than those harvested in the fall. As an example, the late spring harvest under no berry failures had a 1.2% increase, whereas with berry failures, the population growth rate was 0.7%. These 2 values are significantly different (f < 0.05). The final population for no berry failures was 961 (SD 110, SE 11). The final population for the berry crop simulations was 855 (SD 206, SE 21). The population growth rates are very close to significantly different (f < 0.05) for the early spring harvest, but are not different for the fall harvest simulations. The impact of a 10% chance of double harvest significantly (f < 0.05) reduces the rate of population growth compared to where harvest is always the same from year to year. Another impact of the occasional double harvest is a slight increase in the variability of the final populations. For example, the standard deviations for the constant harvest simulations are 106, 110 and 105, but 124, 114, and 100 for the occasional double harvest simulations for early spring, late spring, and fall seasons, respectively. Part of the reason that the fall SD is smaller is that the population was much lower, so that the coefficient of variation would be quite a bit larger for the occasional double harvest simulations. Figure 2 provides a summary of the expected population size after 30 years for 4 of the harvest scenarios. One of the striking differences �93 noted in Fig. 2 is that the annual rate of population growth can be quite different (e.g., 1.2% versus 0.7%), and yet the differences in expected population size after 30 years are not all that great. This phenomena is caused by the linear scale on which the rate of increase is measured, whereas the 30 year population size is on an exponential scale. Another result evident in Fig. 2 is the greater variability of the 100 simulations for cases where berry crop failures occur with probability 0.1. The minimum and maximum values show a greater spread for both the cases where berry crop failures occur. Population 'L 000 3,500 3,000 2,500 2,000 1.500 1. 000 500 after 30 Years l1aximum l1ean l1inimum o Rate of Increase I I "---11~~-d-lmmmm-mm~mm-mm~I~-~J ; N ELF N ELF CDIlStut Beny B:eI."fl' !'allures Bl.nest Figure 2. Population size after 30 years. simulations. N ELF The minimum N ELF Both L r- (%) Icme Barl,. Bpr1q' Lata Bpr1q' Fall and maximum values are obtained from 100 The occasional double harvest can be quite important in limiting population growth. The current harvest levels are close to the maximum that the population can stand, particularly for the fall harvest. Berry crop failures will complicate this management process. The system is more variable, so would be harder to manage because the harvest (and population) would be more variable. Results of simulations of the 6 harvest scenarios with both berry crop failures and double harvest included in the model are presented in Table 1. The slight effect of no cub survival of females harvested in the spring is evident by comparing the late spring season with 35% females in the harvest to the fall season with 35% females. Because cub suvival is low to start with (0.51), and because the probability that the �94 mother will be harvested is low «5%), the effect of total mortality cubs of females harvested in the spring is not a particularly large effect. of Table 1. Results from the black bear simulation model for the case double harvest 10% of the time, plus berry crop failures 10% of the years. No compensation in cub survival as a function of population size was modeled. Values presented are the means of 100 30-year simulations. Hunting Type Season Annual Rate of Pop. Increase (%) Final Pop. Size Females in Harv. (%) Final Harvest Size No harvest 4.5 2480 0.0 0 Early spring l.l 932 30.0 46.03 Late spring 0.6 813 35.0 42.60 Fall 0.3 721 45.0 37.94 Fall 0.6 804 40.0 39.60 Fall 0.9 875 35.0 42.80 LITERATURE CITED Knight, R. R., and L. L. Eberhardt. 1985. Population Yellowstone grizzly bears. Ecology 66:323-334. dynamics of SAS Institute Inc. 1985. SAS Language Guide for Personal Computers, Version 6 Edition. SAS Institute Inc., Cary, NC. 429pp. Prepared by ./~ Gary c. C~ Whlte �95 Colorado Division Wildlife Research July 1989 of Wildlife Report JOB PROGRESS REPORT State of Project Colorado No. ~W_-~1~5~3~-R~-~3 Work Plan Mammals Research 2A Mountain Job No. 4 Experiments to Identify and Manage Stress in Mountain Sheep Period Covered: July 1, 1988 - June 30, 1989 Authors: Personnel: No. _ M. W. Miller Sheep Investigations and N. T. Hobbs M. A. Wild, K. A. Trust, H. J. Lucking, K. M·. Sheehan, Sousa, T. M. Nett, K. W. Mills, and E. S. Williams M. C. ABSTRACT Repositol adrenocorticotropic hormone (ACTH) injected every 48 hrs elevated urinary (P ~ 0.006) and fecal (P ~ 0.014) cortisol excretion in tame bighorns 0-24 hrs after treatment. Urinary cortisol excretion dropped below (P ~ 0.007) control levels >24-48 hrs after ACTH injection, but fecal cortisol excretion by treatment and control bighorns did not differ (P - 0.06) during that time. Our experimental data suggest that sampling excreta from bighorns offers a promising tool for detecting responses to environmental stressors. We reported results of our stress experiments in a doctoral thesis and two manuscripts submitted to peerreviewed scientific journals. Nonhemolytic Pasteurel1~ haemolytica biotype T was recovered .in nasal swabs from tame bighorn ewes prior to lambing, from l-week-old bighorn lambs, and from ewes and lambs during a pneumonia epizootic .in July 1988 that affected 7 of 8 lambs and 1 of 10 ewes; a similar shedding and transmission pattern appears to be developing again in 1989. Epidemiological findings from pasteurellosis studies in our captive bighorn herd offer insights into patterns of lamb mortality following pneumonia outbreaks in wild bighorns. ��97 PLANE OF NUTRITION AND BIGHORN POPULATION PERFORMANCE SHEEP M. W. Miller N. T. Hobbs P. N. Objective To treat bighorn sheep to control disease where necessary. SEGMENT OBJECTIVES 1. Assess the utility of urine and fecal samples to indicate environmental stress in mountain sheep populations. 2. Publish results in peer-reviewed USE OF FECAL CORTISOL RESPONSES scientific journals. TO DETECT SIMULATED CHRONIC STRESS Applying techniques for measuring cortisol in feces that we developed and described earlier (Miller and Hobbs 1988, Miller 1988), we detected marked changes in fecal cortisol excretion in bighorns treated with ACTH; details of the design and preliminary results of that experiment are reported elsewhere (Miller and Hobbs 1987, Miller 1988). Acute responses to alternate-day ACTH treatment were characterized by more than a 4-fold increase (P < 0.006) in mean urine cortisol:creatinine ratios (UCCRs) for the period from 0-24 hr after treatment (Fig. la). Fecal cortisol excretion followed a similar pattern of lesser magnitude; FCCs increased (P < 0.014) by more than 50% in ACTH-treated bighorns (Fig. lb). We detected no evidence for cumulative effects of chronic ACTH treatment on acute urine or fecal cortisol responses (time*treatment P > 0.05). Cortisol excretion 25-48 hr after ACTH treatment was lower than we anticipated. We observed no progressive increase in cortisol excretion between successive treatments (time*treatment P > 0.05). Instead, 25-48 hrs after they received ACTH, mean UCCRs were substantially lower (P < 0.007) in treated bighorns as compared to controls (Fig. la). The trend toward reduced FCes in treated sheep approached significance (P - 0.063) (Fig. lb). Our results suggest that cortisol excreted in feces, as in urine, may be used to detect adrenal responses in bighorn sheep. �98 EXPERIMENTS TOWARD DETECTING AND MANAGING STRESS IN BIGHORNS Results of the stress experiments in bighorns to date were summarized in a doctoral dissertation and two manuscripts submitted to peer-reviewed journals. The abstracts of these follow: Miller, M. W. 1988. Experiments toward detecting and managing stress in Rocky Mountain bighorn sheep (Ovis canadensis canadensis). Ph. D. Thesis. Colorado State University, Ft. Collins. 106 pp. Abstract: Endocrine responses of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) to environmental stressors are believed to predispose them to disease. Methods for detecting adrenal responses in bighorn sheep were evaluated in a series of experiments. Average maximum serum cortisol concentrations (SCC) (ng/ml) from tame bighorns responding to physical restraint (hobbling) or exogenous adrenocorticotropic hormone (ACTH) (20 U iv) did not differ (P = 0.11). Bighorns responding to restraint with high maximum SCCs responded to ACTH with SCCs of similar magnitude (r2 = 0.84, P < 0.05). In a ser-cate study, plasma cortisol concentrations (PCCs) (ng/ml) and ur Lr;., cortisol: creatinine ratios (UCCRs) (ng /mg) from tame bighorns rose in response to repositol ACTH treatment. PCCs and UCCRs were correlated (r2 - 0.72, P < 0.001) after adjusting for lag in urinary cortisol excretion. Alternate-day repositol ACTH administration was used to simulate chronic stress responses in tame bighorns. Adrenal responses to ACTH were reflected by elevated mean 24hr UCCRs (P < 0.002) and fecal cortisol concentrations (FCCs) (ng/g dm) (P < 0.014) from bighorns on treatment days. Mean 24hr UCCRs from days between treatments were lower (P < 0.007) in ACTH-treated bighorns than in controls, and mean 24hr FCCs showed similar but weaker (P - 0.06) trends. Treated bighorns showed depressed lymphocyte blastogenic responses to lipopolysaccharide (P - 0.02), but not concanavalin A or phytohemagglutinin, by day 41 of each treatment period. However, no cumulative pattern was evident in elevated urinary or fecal cortisol excretion accompanying these changes. Urine-stained snow samples provided reliable estimates of UCCRs from voided bighorn urine (r2 - 0.87, P < 0.001). Tame bighorns exposed to a novel environment showed elevated cortisol excretion in both urine and feces. UCCRs and FCCs from 10-day composite samples were higher (P <0.05) in nonhabituated bighorns than in sheep previously habituated to metabolic cage confinement. Most (13 of 16) 24hr UCCRs from 4 tame bighorns that developed pneumonia equaled or exceeded upper 95% confidence limits for mean 24hr UCCRs from 8 clinically normal bighorns sampled over the same time interval. Elevated UCCRs preceded clinical signs of pneumonia by 5 12 days. �99 These results support further development of urine and fecal cortisol measures as noninvasive techniques for detecting adrenal responses in bighorn sheep, and perhaps other species. Both approaches offer potential use in testing hypotheses related to stress and the pneumonia complex of bighorn sheep. They may have broader application in studies of stress responses in a variety of other species. Miller, M. W., N. T. Hobbs, and M. C. Sousa. 19 Sampling adrenal responses in bighorn sheep (avis canadensis): reliability of cortisol concentrations in urine and feces. Can. J. Zool., in review. Abstract: We evaluated the reliability of cortisol concentrations in urine and feces to indicate responses to stress in captive Rocky Mountain bighorn sheep (avis canadensis canadensis). Tests for parallelism and quantitative recovery of cortisol in bighorn plasma, urine, and fecal supernatant revealed that radioimmunoassay reliably measures cortisol in these media. In a randomized complete block experiment, we observed cortisol responses of 8 bighorn sheep to 2 levels of adrenocorticotrophic hormone (ACTH) injections (0.0 and 0.50 U/kg) delivered at 48 hr intervals over a 29-day period. Treatment elevated (P < 0.01) cortisol in urine and fecal supernatant during 0-24 hrs following ACTH injections, but levels dropped below those of controls during 24-48 hrs posttreatment. Magnitude of ACTH effects did not change with time during the experiment (time X treatment P > 0.05). In a separate experiment, we observed short-term (0, 2, 4, 8, 12, 24 hr) cortisol responses in plasma, urine, and feces from 8 bighorns following a single challenge with 1 of 4 levels of ACTH (0.0, 0.25, 0.5, 1.0 U/kg). We failed to observe a dose response above the 0.5 U/kg level in any media. Concentrations of cortisol (ng/ml) in plasma were correlated (r2 - 0.76) with cortisol:creatinine ratios (ng/mg) in urine. We conclude that sampling excreta of bighorn sheep offers a promising alternative to blood sampling as a means of detecting responses to environmental stressors. Miller, M. W., N. T. Hobbs, and E. S. Williams. 19 Spontaneous pasteurellosis in captive Rocky Mountain bighorn (avis canadensis canadensis): clinical, laboratory, and epidemiological observations. J. Wildl. Dis., in review. sheep Abstract: We observed clinical signs, compared adrenal responses, and performed diagnostic tests on captive Rocky Mountain bighorn sheep (avis canadensis canadensis) during a spontaneous outbreak of pasteurellosis. Urine cortisol levels were measured for 12 bighorns sampled three times between 20 October and 1 November 1986. By 6 November, four of these developed pneumonia, four �100 showed only mild rhinitis, and four remained clinically normal; a similar pattern emerged in five unsampled sheep. Bighorns that ultimately developed pneumonia showed higher urinary cortisol excretion (P - 0.0034) over the l2-day sampling period. Elevated urine cortisol:creatinine ratios (UCCRs) preceded clinical pneumonia in affected bighorns by ~ 16 days. Mean UCCRs from pneumonic bighorns were 1.5- to 2 times those of mildly affected or unaffected sheep (P < 0.05) in two of three 48-hr. collection periods, but mean UCCRs from mildly affected and unaffected bighorns were indistinguishable (P > 0.05). Pasteurella haemolytica biotype T (nonhemolytic variant) was isolated from nasal and pharyngeal swabs from all bighorns with pneumonia, and from three of four sheep with mild rhinitis. We detected no evidence of parainfluenza 3, bovine respiratory syncytial virus, or Chlamydia psittaci using fluorescent antibody and/or serologic tests. Susceptibility to pneumonia in this outbreak appeared related to lack of previous exposure to pasteurellosis. In light of these data, we offer a refined hypothesis to explain epizootiology of the bighorn pneumonia complex. EPIDEMIOLOGY PNEUMONIA OUTBREAKS IN CAPTIVE BIGHORN LAMBS Poor lamb production and survival often follow pneumonia epizootics in bighorn herds. This carryover effect on recruitment typically prevents immediate recovery of bighorn numbers after an all-age die-off, and can lead to formation of small remnant populations. Lamb mortality usually results from pneumonia, but epidemiology for this facet of the pneumonia complex in bighorns remains undescribed. During the summers of 1988 and 1989, we've had the opportunity to gain some insights into pneumonia outbreaks in bighorn lambs. Methods and Materials: We hypothesized that bighorn ewes carrying Pasteurella haemolytica shed bacteria in nasal secretions during the periparturient period. As a result, their lambs are infected with Pasteurella early in life, and may succumb to pneumonia later in the summer. Using our tame bighorn herd, we examined epidemiology and diagnosis of pasteurellosis in bighorn lambs. During late April-August 1988, we simulated formation of a nursery band as described for wild bighorns, and monitored the spread of P. haemolytica through this ewe/lamb herd (n-l8); rams (n-6) maintained separately served to some extent as a control group. We held 6 tame ewes in isolation pens (about 50 mZ) from late April until 14 days after respective lambing dates, and allowed 2 wild ewes to lamb in a separate pasture. A single nursery group was constructed by adding ewe/lamb pairs as lambs reach 14 days of age. We added 2 barren ewes (ages 1 and 10 yr) to the nursery group about 1 week after the last pair entered. The resulting nursery band occupied 2 interconnected 4-ha pastures. We provided water, alfalfa hay, and a pelleted ration ad libitum in a single location in the pen complex, and natural forage was also available. �lOl We collected nasal swabs from tame ewes (n~6) prior to parturition, and from tame ewe/lamb pairs weekly until they joined the nursery band. Thereafter, ewes and lambs were sampled about every 2 weeks. We transported swabs in modified Amies medium with charcoal, and submitted them within 12 hrs for bacterial culture. Bacterial growth was screened for presence of Pasteurella spp. We observed ewes and lambs daily for signs of respiratory disease, and weighed each animal weekly. As lambs developed pneumonia, we removed them from the study and initiated antibiotic therapy (amoxicillin and gentamicin for 5 days followed by long-acting oxytetracycline for 7 - 10 days). We continued to monitor bacterial shedding in nasal swabs from tame bighorns by sampling in October 1988 and March 1989 in conjunction with other handling procedures. From mid-April 1989 to present, we began monitoring prevalence and transmission of P. haemolytica between isolated and semi-isolated bighorn ewe-lamb pairs. We maintained 8 tame ewes in isolation pens (about 50 Water, alfalfa hay, and a pelleted ration m2) beginning in mid-April. were provided ad libitum. We isolated 4 ewes in pens spaced about 5 m apart with individual water sources. Four others ewes were paired and held in 2 sets of adjacent pens; each set shared a common water source, and pens were separated by a pole fence that allowed nose-to-nose contact. We have weighed ewes and collected nasal swabs and serum weekly. Lambs were weighed, bled, and nasal swabs collected within 12 hr of birth; we sampled lambs weekly thereafter on the same schedule used for ewes. We are observing all bighorns daily for signs of respiratory disease. Beginning 17 July, we will immobilize lambs weekly with xylazine (about 3-4 mg IV) and collected tonsillar swabs and tracheal aspirates in addition to blood and nasal swabs. Ewes will be immobilized once in late July using ketamine and xylazine (about 91 mg and 9 mg IV), and we will collected tonsillar swabs and biopsies in addition to nasal swabs. We will screen bacterial growth for presence of Pasteurella spp., and submit isolates to the Wyoming State Veterinary Laboratory for biotyping and serotyping. Lambs that develop pneumonia will be removed from the study and treated with antibiotics as described previously. Results and Discussion: In 1988, 2 of 6 tame ewes (C83, T82) shed Pasteurella spp. before and after lambing; one of these (T82) shed intermittently throughout the summer. Aside from serous to mucopurulent nasal discharge, no clinical signs of respiratory disease were seen in these ewes. Clinical signs of pneumonia first appeared on 1 July in a 6-week-old ram lamb (C88). By 9 August, 7 of 8 lambs and a yearling ewe (L87) had developed pneumonia. In all, 8 of 8 lambs and 4 of 10 tame ewes shed Pasteurella spp. in nasal secretions during the outbreak. All lambs and the yearling affected by pneumonia recovered uneventfully after antibiotic therapy. The only mortality resulted from euthanasia of the index case in order to perform a complete diagnostic workup. �l02 The most common Pasteurella spp. isolate in 1988 was nonhemolytic, did not ferment indole, and did not produce catalase; this culturaljbiochemical profile is characteristic of the "bighorn strain" of P. haemolytica biotype T (Onderka and Wishart 1988, Onderka et al. 1988). Another Pasteurella isolate, similar to the first but catalase positive, was recovered occasionally. Pasteurella multocida (nonhemolytic, indole positive) grew from lung of the index lamb. We detected no serologic titers to Parainfluenza 3 (PI3) or Bovine Respiratory Syncytial (BRSV) viruses; no lungworm (Protostrongylus spp.) larvae were shed in feces from lambs. We concluded that Pasteurella spp. caused this outbreak, and that parasitism and viruses were not involved. We isolated Pasteurella spp. from 5 of 17 nasal swabs collected from tame sheep on 28 October 1988, more than 2 months after the summer outbreak subsided. Four of 7 lambs (including the lamb that did not develop clinical pneumonia) and 1 of 8 ewes were shedding bacteria at that time. In March 1989, we again isolated non-hemolytic P. haemolytica from 2 of 20 nasal swabs collected from our tame bighorns. Two of 7 lambs (including the lamb that did not develop clinical pneumonia) were still shedding bacteria at that time; none of the 13 swabs from adult sheep (rams or ewes) were positive. These isolates displayed metabolic profiles resembling P. haemolytica biotype A, in contrast to most previous isolates. Findings from 1989 are still preliminary, and no cases of pneumonia had developed by 1 July. However, we recovered Pasteurella spp. in nasal swabs from 3 of 8 ewes prior to lambing, and from 3 of 8 lambs (not necessarily related to shedding ewes) sampled at 1 week of age. As in 1988, prevalence of Pasteurella spp. recovered from nasal swabs was relatively low during June. Isolates recovered to date have been predominantly non-hemolytic and catalase negative, resembling the biotype T strain present in 1988. Early attempts to serotype recent isolates suggest nonspecific cross-reactivity with both type 3 and 4 antisera. Several features of these investigations bear emphasis. Bighorn ewes can carry and shed Pasteurella spp. without developing pneumonia; at least 1 lamb (the daughter of a carrier ewe) shed without clinical signs, as well. Furthermore, we detected preclinical shedding in lambs up to 1 wk before signs were noted. Both of these conditions shed some light on how Pasteurella spp. persist in and spread through bighorn herds. No consistent pattern for initiation of these outbreaks has emerged, although the first cases of pneumonia developed in early July -- that timing may coincide with loss of colostral antibody protection against Pasteurella spp. Once started, lamb-lamb transmission seems relatively important in sustaining epizootics. Most lambs affected in 1988 would probably have died in the wild; those not succumbing to pneumonia would have been quite vulnerable to predation, accidents, or exposure. Field accounts suggest that lambs "disappear" in mid-summer following dieoffs, and our findings provide a plausible explanation for these observations. Over two summers, the only adult ewe that developed pneumonia was a yearling that had not been exposed to previous outbreaks in our herd. We suggest that persisting immunity to Pasteurella spp. may protect adult bighorn from pneumonia, and that "all-age" dieoffs may result from a �103 rapid accumulation of immunologically naive sheep in a population where some carriers have survived. It follows that preventing pneumonia in bighorns may rely more on controlling growth rates of herds rather than total numbers. The role of stress in these outbreaks remains unclear; initiation of shedding by carrier animals seems to be a logical alternative to invoking some "population-wide" response to environmental adversity as the inciting mechanism. If carriers are less "fit" or "vigorous" than other individuals, they might be forced into less desirable social and environmental niches. The cumulative stresses associated with these suboptimal conditions could then lead to immunosuppression and, subsequently, induce Pas~eurella spp. shedding. In the presence of enough susceptible individual (adults or lambs), a pneumonia outbreak may ensue. LITERATURE CITED Miller, M. W. 1988. Experiments toward detecting and managing stress in Rocky Mountain bighorn sheep (Ovis canadensis canadensis). Ph. D. Thesis. Colorado State University, Ft. Collins. 106 pp. Miller, M. W., and N. T. plane of nutrition Colo. Div. Wildl., 26-P, WP2, J4, Job Hobbs. 1987. Mountain sheep investigations: and bighorn sheep population performance. Wildl. Res. Rpt., Part 2. Fed. Aid Proj. FWProg. Rpt., Ft. Collins, pp. 213-224. Miller, M. W., and N. T. plane of nutrition Colo. Div. Wildl., l53-R-2, WP2A, J4, Hobbs. 1988. Mountain sheep investigations: and bighorn sheep population performance. Wildl. Res. Rpt., Part 2. Fed. Aid Proj. WJob Prog. Rpt., Ft. Collins, pp. 99-112. Onderka, D. K., and W. D. Wishart. 1988. Experimental contact transmission of Pasteurella haemolytica from clinically normal domestic sheep causing pneumonia in Rocky Mountain bighorn sheep. J. Wildl. Dis. 24: 663-667. Onderka, D. K., S. A. Rawluk, and W. D. Wishart. 1988. Susceptibility of Rocky Mountain bighorn sheep and domestic sheep to pneumonia induced by bighorn and domestic livestock strains of Pasteurella haemolytica. Can. J. Vet. Res. 52: 439-444. Michael W. Miller Wildlife Researcher �104 • A 40, B 10g. 8· 7· ......J 6- (j) 5, o tco o ......J (5 UJ LL 12345678 12345678 f- ACTH -1 t- CONTROL ~ TIME = 0 - 24 hrs iZZl 25 - 48 hrs 12345678 12345678 '-. ACTH ---: '_CONTROL - TIME ;:::;::::J 0-24 hrs ~ 25-48 hrs Figure 1. Responses of tame bighorns (n = 8) to alternate-day ACTH (treatment) or saline (control) injections. We initiated treatments at the beginning of sampling period 4. Sampling periods were 6 days long and included 2 days of urine and fecal collections. Urine and fecal collections were divided into samples representing 0-24 and >24-48 hrs after injection. Treatment elevated cortisol excretion in both (A) urine (P ~ 0.006) and (B) feces (P ~ 0.014) in the first 24 hrs after ACTH injection. �105 Colorado Division Wildlife Research July 1989 of Wildlife Report JOB FINAL REPORT State of Project Colorado No. W-1S3-R-3 Work Plan No. -=2~A~ Job. No. 5 Period Covered: Author: Mammals _ Research Mountain Sheep Investigations Tests of the Mark-Recapture Method to Estimate Mountain Sheep Numbers July 1, 1988 - June 30, 1989 D. F. Reed ABSTRACT Fixed-wing flights were made on 10 November and 16 December 1988 to locate and determine the status of the 28 radio-collared female mountain sheep prior to the 15 replicate helicopter counts. During the flights and a ground telemetry check on 5 January 1989, 3 collars (Black E, Black F, and Black triangle) were found transmitting mortality signals. They were later confirmed to be mortalities. This reduced the total number of telemetry marks in the study population to 25. The lS helicopter counts were conducted as planned from 13 January through 23 February 1989. Preliminary analyses indicate variable resighting probabilities for the 25 marks. Overall, 57.5% (range = 35.7 85.7) of the marks that were in the study area were resighted during 14 of the 15 counts. Fifteen of the 25 marks were always in the study area, while 10 were out of the study area for varying occasions (n - 1-10). The mean number of animals counted arid marks resighted were' 58.5 (± 14.1 [SD]) and 11.5 (± 3.6) (ranges - 30-87 and 6-10), r~spective1y. Movements of the te1emetered animals before, during, and after the 15 'counts varied between individuals. ��107 TESTS OF THE MARK-RECAPTURE METHOD TO ESTIMATE MOUNTAIN SHEEP NUMBERS Dale F. Reed P. N. OBJECTIVE Test the fundamental assumption mountain sheep numbers. of a mark-recapture procedure in estimating SEGMENT OBJECTIVES 1. Complete 15 helicopter count replications. 2. Quantify the extent to which mark-recapture in mountain sheep population estimates. 3. Test the robustness data. of those assumptions model assumptions via simulations are violated with actual field ACKNOWLEDGMENTS I thank co-principal investigators R. B. Gill and G. C. White, graduate assistant A. K. Neal, and J. H. alterman. B. Metcalf piloted the Soloy helicopter, and R. Broomfield provided helicopter support. Saguache District Ranger J. Krugman provided the USFS Upper Saguache Guard Station for a housing and work center. DESCRIPTION Description of area was presented OF AREA in Reed (1988). METHODS AND MATERIALS Fixed-wing flights were made on 10 November and 16 December 1988 to locate and determine the status of the 28 radio-collared mountain sheep (Table 1). Following these counts and observations and telemetry from the ground, an estimate was made as to the area to be covered during the censuses or counts (Fig. 1). The first of the 15 counts was to be the flight path and area determinate i.e. each of the following flights would replicate the first flight path and covered to the greatest extent possible. The same helicopter and pilots used for each flight. The observers occupied the same positions in the helicopter (observer 1 betweenpilot and outboard observer (2]) during each of the flights. Both observers used hand-held taperecorders. Additionally, observer 1 carried binoculars for collar identification if needed and observer 2 a 35mm camera with 100-300mm zoom lens for recording animal groups for later classification, collar identification, and/or animal behavioral response to helicopter. �108 Each observer voice-recorded the number of animals in the group, number and identification of collars, and location. The aircraft intercom system and gestures (pointing) were used to alert pilot and observers to animals when they were first sighted. To reduce or eliminate error, observers conferred before or during voice-recordings. Observers agreed on whether needed information had been obtained before the pilot was instructed to "break-off" from the group and continue on the flight path. Upon completion of each count, the observers transcribed information from the recordings to field forms and marked locations onto a "master" 1:64,000 quad map. Then an additional flight was made using telemetry with 2 directional-finding antennas (1 fixed position and 1 hand-held) and observer 1 to verify the location ("in" or "out" of study) and status (alive or dead) of all marks that had not been sighted during the count in order to satisfy the "closed population" assumption. Fixed-wing flights were made on 23 May and 6 June 89 to locate and determine status of the 25 radio-collared animals after the counts and winter. RESULTS AND DISCUSSION Two fixed-wing flights were completed before the 15 helicopter counts were initiated on 13 January 1989 (Table 2). Three mortalities occurred before the counts were begun (Table 3). All 15 counts were conducted in the mornings. They were begun between 0814-1002 and completed between 1001-1141 DST. The verification flights (for determining "in" or "out" and mortality status) were begun between 1137-1309 and completed between 1259-1404 DST. Weather conditions were generally mild with a few occasions having light winds and one (6th count) having a low cloud ceiling and snow toward the end of the count. Snow cover varied from near 0 to 100% newly fallen snow. Most analyses will be done during the next segment. However, preliminary analyses indicate variable resighting probabilities for the marked animals en = 25) in this study. Overall, 57.5% (range - 35.7 - 85.7) of the marks that were in the study area were resighted during 14 of the 15 counts (Table 4). Fifteen of the 25 marks were always in the study area, while 10 were out of the study area for varying occasions (n - 1 - 10). The mean number of animals counted and marks resighted were 58.5 (± 14.1 [SD]) and 11.5 (± 3.6) (ranges 30 - 87 and 6 - 10), respectively (Table 5). Locations of the telemeterd animals before, during, and after the 15 helicopter counts suggest variable movements and sizes and areas of winter and summer home ranges (Figs. 2 - 27). A question that arose during the counts was, "Did given animals move after being counted as a result of the aerial procedures?". LITERATURE CITED Reed, D. F. 1988. sheep numbers. Prepared ~E-~ Dale Tests of the mark-recapture method to estimate mountain Colo. Div. Wi1dl. Game Res. Rep. July, Part 2:113-137. F. Reed Wildlife Researcher �109 Table 1. Number assigned to animal, collar description, channel, pulse, activation date, and status for telemetered mountain sheep Trickle Mountain study. Animal no. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Collar Channel description Blue white 01 Blue orange 02 Blue square 03 Black A 04 Black E 05 Black F 06 Black H 07 Black J 08 Black K 09 Black M 10 Black NI 11 Black P 12 13 Black R 14 Black S Black T 15 Black U 16 Black ~ 17 18 Black X 19 Black Y Black Z 00 Black NII 11 Black triangle 09c Red dot 10 Red 1 11 Red 2 12 Red 3 13 Red 4 14 Red 5 15 Red 6 16 Red 7 17 aNo. - estimated Frequency (MHz) 172.787 172.812 172.862 172.912 172.962 173.012 173.062 173.112 173.162 173.237 173.262 172.837 172.887 172.937 172.987 173.037 173.087 173.137 173.187 173.212 173.237 172.487 172.512 172.537 172.562 172.587 172.612 172.637 172.662 172.687 age, A - active Pulse per min. (ppm) 60-110b 60-110 60-110 60-110 60-110 60 -110 60 -110 60-110 60 -110 60 -110 60-110 60-110 60 -110 60 -110 60-110 60-110 60 -110 60-110 60-110 60-110 60-110 60 60 60 60 60 60 60 60 60 (collar frequency, in the Activati0~ date 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 1 Feb 17 Mar 3 Apr 17 Mar 23 Mar 23 Mar 23 Mar 23 Mar 3 Apr 3 Apr 3 Apr 3 Apr transmitting), 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 88 Status 3A 4A 4A SA 4D 4D 3A 4A SA 3D 4D 6-12A 7A SA 6A 3A SA SA 4A SA 7A 3D 4A 6A 4A 3A 7A 2U 2A SA and D - animal died. bMorta1ity sensors: 60 ppm - alive, 110 ppm - dead (no movement period of 4 hrs). Sheep 22-30 do not have mortality sensors. cSecond series of numbers is for a second Te10nics TR 1 receiver. for �110 Table 2. Flight date, aircraft type, number of mountain sheep observed. number of mountain sheep with transmitters observed, and number of transmitters located and not located. Flight date 17 23 3 5 7 22 10 16 13 14 17 18 19 27 28 1 2 8 9 15 16 22 23 16 6 Mar Mar Apr May Jun Jun Nov Dec Jan Jan Jan Jan Jan Jan Jan Feb Feb Feb Feb Feb Feb Feb Feb May Jun Aircraft 88 88 88 88 88 88 88 88 89 89 89 89 89 89 89 89 89 89 89 89 89 89 89 89 89 Table 3. stud Soloy Helicopter Soloy Helicopter Soloy Helicopter Cessna 185 Cessna 185 Cessna 185 Cessna 185 Cessna 185 Soloy Helicopter Soloy Helicopter Soloy Helicopter Soloy Helicopter Soloy Helicopter Soloy Helicopter Soloy Helicopter Soloy Helicopter Soloy Helicopter Soloy Helicopter Soloy Helicopter Soloy Helicopter Soloy Helicopter Soloy Helicopter Soloy Helicopter Cessna 185 Cessna 185 Mortality Observed wi transmitters t::lI1e Observed 39 41 46 5 20-30 39 5 79 68 68 62 66 57 52 61 87 48 64 30 69 35 52 57 28 16 of collared Transmitters located 14 12 13 1 1 5 1 8 7 11 11 14 11 10 9 19 8 13 8 14 6 13 17 11 0 female mountain Transmitters _E_ot located 4 16 27 26 26 24 23 24 24 23 24 24 25 24 23 25 25 24 25 25 21 22 24 12 1 0 0 1 2 1 1 2 1 1 0 1 2 0 0 1 0 0 4 3 sheep in the Trickle Mountain Date No. 10 11 5 6 22 Collar Black Black Black Black Black M N1 E F triangle Age 3 4 4 4 3 Marked 1 1 1 1 17 Feb Feb Feb Feb Mar 88 88 88 88 88 RecoveredL:Death < 5 Feb 88 < 23 Mar 88 < 10 Nov 88 < 10 Nov 88 16 Dec 88-5 Jan 89 Estimated cause Capture myopathy Capture myopathy Illegal kill Unknown Unknown �ill Table 4. Frequency, Frequency Cell Chi -Square Percent Row Pct Col Pct chi-square, and resighting I I I I Inot sigh1sighted Ited I I I Frequency Cell Chi-Square Percent Row Pct Col Pct Total ---------------+--------+--------+ bear 2 12 2.6168 1.9307 0.70 4.21 14.29 85.71 1.65 7.32 - - - - - - - - - - - - - - -+- - - - - - - -+- - - - - - --+ besq 4 10 0.6357 0.469 1.40 3.51 28.57 71.43 3.31 6.10 14 14 1 0,9399 0.35 16.67 0.83 5 0.6935 1.75 83.33 3.05 4 10 0.6357 0.469 1.40 3.51 28.57 71.43 3.31 6.10 - - - - - - - - - - - - - - -+- - - - - - - -+- - - - - - --+ bkfe 5 9 0.1499 0.1106 1.75 3.16 35.71 64.29 4.13 5.49 ---------------+--------+--------+ bkh animal. I I I I Inot sigh-Isighted Ited I 3 3 0.0804 1.05 50.00 2.48 0.0593 1.05 50.00 1.83 7 0.3972 2.46 53.85 5.79 - - - - - - - - - - - - - - -+- - - - - - - -+6 2.11 14 4.91 14 4.91 I I Tota. 2.1 ---------------+--------+--------+ bkj 4.91 ---- - ---- - - --- -+- ----- --+- ---- ---+ bka ~2T~~C ---------------+--------+--------+ 4.91 ---- ----- - ---- -+- -------+- ---- ---+ bewh percent per 7 0.1877 2.46 50.00 5.79 - - - - - - - - - - - - - - -+- - - - - - - -+bkn 9 1.5714 3.16 64.29 7.44 - - - - - - - - - - - - - - -+- - - - - - - -+bkp 9 1.5714 3.16 64.29 7.44 - - - - - - - - - - - - - - -+- - - - - - - -+- bkk 6 0.2931 2.11 46.15 3.66 - - - - - --+ 7 0.1385 2.46 50.00 4.27 - - - - - --+ 5 1.1594 1.75 35.71 3.05 - - - - - --+ 5 1.1594 1.75 35.71 3.05 - - - - - --+ 1. 4.Si V4.91 14 4.91 14 4.91 �112 Frequency , Ce11 Chi -Square' Percent , Row Pct , Col Pct 'not sigfrlsighted I I ted I I Total 6 8 0.0005 I 0.0004 2.11 I 2.81 42.86' 57.14 4.96 I 4.88 14 1 0.2871 0.35 25.00 0.83 I I I I 3 0.2118 1.05 75.00 1.83 ---------------+--------+--------+ redl I 2 4 I 0.1176 I 0.0868 I 0.70 I 1.40 I 33.33 I 66.67 I 1.65 I 2.11, 50.00 I 4.96 I 2.11 50.00 3.66 I - - - - - - - - - - - - - - -+- - - - - - - -+- - - - - - --+ I 12 14 I 2.6168 I 1.9307 I 0.70 I 4.21 I 14.29 I 85.71 4.91 I 4 bks 1.40 2 1.65 I 7.32 4 0.3556 1.40 57.14 3.31 3 7 I 0.2624 I 1.05 I 42.86 I 1.83 2.46 ---------------+--------+--------+ 6 bkt 2.11 3 0.0463 1.05 37.50 2.48 5 0.0341 1.75 62.50 3.05 8 2.81 ---------------+--------+--------+ 4 bku 1.40 6 8 0.0005 I 0.0004 2.11 I 2.81 42.86 I 57.14 4.96 I 4.88 14 4.91 ---------------+--------+--------+ 12 I 0.1609 , 0.1187 I Total ---------------+--------+--------+ 2.44 ---------------+--------+--------+ red2 I 1 3 I 0.2871 I 0.2118 I 0.35 I 1.05 I 25.00 I 75.00 I 0.83 I 1.83 ---------------+--------+--------+ red3 I 6 6 , bkr 4.91 ---------------+--------+--------+ bkz I I ---------------+--------+--------+ ---------------+--------+--------+ bky Frequency I Cell Chi-Square I Percent I Row Pct I Col Pct Inot sigh-I sighted Ited I 4.21 bkx 5 9 0.1499 0.1106 1.75 3.16 35.71 64.29 4.13 5.49 - - - - - - - - - - - - - - -+- - - - - - - -+- - - - - - --+ 14 4.91 �1.13 Frequency Cell Chi-Square I Percent I Row Pct I Col Pct [rio t; sigh-jsighted I Ited I I Total ---------------+--------+--------+ red4 8 0.7113 2.81 57.14 6.61 6 0.5248 2.11 42.86 3.66 14 4.91 ---------------+--------+--------+ redS 8 0.7113 2.81 57.14 6.61 6 0.5248 2.11 42.86 3.66 14 4.91 ---------------+--------+~-------+ red6 6 1.2425 2.11 66.67 4.96 3 0.9168 1.05 33.33 1.83 9 3.16 ---------------+--------+--------+ red7 7 0.1877 2.46 50.00 5.79 7 0.1385 2.46 50.00 4.27 14 4.91 ---------------+--------+--------+ redo 5 0.1499 1.75 35.71 4.13 9 0.1106 3.16 64.29 5.49 14 4.91 --- - ---- - ------+- - -- ----+- ----- --+ Total 121 42.46 164 57.54 285 100.00 �Table s. Number of mountain sheep counted, marks (radio collars) out of the study area, and classification of the animals counted. No. marks Date 13 14 17 18 19 27 28 1 2 8 9 15 16 22 23 Counted Jan Jan Jan Jan Jan Jan Jan Feb Feb Feb Feb Feb Feb Feb Feb x 68 68 62 66 57 52 61 87 48 64 30 69 35 53 57 58.5 Sighted sighted, marks Classification Out Adult female .£ Young female 8 11 11 14 11 10 9 19 8 13 8 14 6 13 17 7 11 4 4 5 5 5 3 7 2 7 5 8 5 4 13 32 30 26 26 25 27 39 24 31 19 33 20 26 32 5 11 15 14 12 12 15 25 12 16 6 17 9 14 18 2 4 5 4 6 3 5 8 2 5 1 3 3 7 4 ll.s 5.5 26.9 13.4 4.1 Young male Adult femrl1e 2 0 0 0 1 1 0 0 0 2 1 0 0 13 13 12 15 11 11 14 10 9 9 3 12 3 6 3 33 8 0 7 1 0 0 5 9.6 4.0 0 O· 0.5 Unknown 1 1 0 4 0 0 0 �4235-.--------Spanish Creek Rd ~ -'3 -.···l· ..".\ E ~ 4231-1 ~ o North,\ .. , -, Pass .s: \. _ -, . ~ s •.....• ..c 1:: 4227 g 'Il ~ ~ ?- Buffalo Pass Campground t- ::> Trickle ~ Mountain 4223 RaM,. VUf( Ca/7YO/7 421 9--1 358 362 366 370 a. ~O' ~ ~ Benny ~ :::0 Q'C}~ ~ ,.>.' .•... ~ ~C'f' ~, -Y('/ . . ,/ .' -"-", l~ •.... '\ ~~ .{) Houghland "'" ..••••.....•••.• - ..- ..~ . '\ \0 Hill Hi9hW(l· -._./ .Y 711--r-r---.-r--.---r---'-'-1---'---' 374 378 382 386 390 UTM east/west km Fig. 1. The areas covered (shaded) during the 15 helicopter counts. Each flight departed tile Guard Station, first searching the area west and southwest of the Guard Station, then the main Trickle Mountain area from the eastern most part near Lone Tree Gulch and proceedinq clockwise, then counterclockwise over the area between Lone Tree Gulch and Jack's Creek Road, then north, east, and south over the horseshoe shaped area south of Middle Creek, and then north and northeast of the Guard Station during the return. r-' r~ \J1 �4235~----~~~~~--------------------------------~ SpanIsh Creek Rd . /~( 4231 3.~.. . +.. , l \fJ«' North Pass E ~ \ '~' "iJ %; \ .-- ..-, t:: s \ 9- Campground 'il Benny ~ ~ ~ , ", Rabbit~~~. al]YOn , I I I I 362 I I I , 366 I , I 370 , •• •• •• Trickle ~, Guard Mountain, '.. •••••...~ .• - •••.•••.••~ I I I , 374 UTM east/west \ ",' .-:~.t \ " 'x _._ .~. _. -.- Stta" Ion : .'\ k .... fl'" .. ....." 1A" " "1 358 Q ~--.l ~ 4227 4219I ( 0' ", ~ s :i: ..__~ !~ i t-" t-' 378 km ~. ....-\. '<. HOIjghland Hill 'x /' J.ng/}Wa·-·- . I I 1:Y ,111 I •. : _;'P"\'. ~ I I I 382 I I I 386 I I I 390 * = • = Nov 10. 1988 • = June 7. 1988 June 22. 1988 ~ = Dec 16. 1988 Fig. 2. Black F (Channel 6,173.01 MHz) (---), Black triangle (Channel 22,172.49 MHz) (_._), and Black E (Channel 5,172.96 MHz) (- - -) locations were determined by telemetry during fixed-wing flights on 7 and 22 Jun 88, 10 Nov 88, and 16 Dec 88. Black E and F were trapped with the dropnet at "X" 1 reb 88 and were transmitting mortality siqnals by 10 Nov 88. Black trianqle was captured with the net gun from helicopter at "x" 17 Mar 88 and was transmitting a mortality signal by 5 Jan 89. I I �4235 Spanish Creek Rd 4231 ~'~~ E Pass' .!Ii::: s: ::; 4227 Ca s ,. <r">. ~ Buff'a 0 Pass Campground <:;) ~ t- :::l 4223 I / -.-=:-13',(\12,14 4 / / J..~. "'t' ~ / 0' .' . / . ••••••• ,.. ••_ C1!1,yOf) •• _ 'f- " / / '~1O . ~ 1 .~ ' ..•...0 '\. 2 . 7(.., ;)~~ .•.._. / Trickle'" Mountain ~, ~ 3 /' __ -- .••.. --~-- / ~ 9/11:tJ /~ Benny \ ...•- {\", . ~-:s2 \ o- Rllbb;t C -i 4219 358 -- /L}: Q('i) _ -. / "7{~/~ <p. ij) , ~ 0 5 ~OL -o9>. round , Cochetopa Pass ~._ ~ Ludsr's Crss< g ••.... s: t ~.. North ,.. ~ / 7'(/'" 6• '\' _,)- //r ~ ••~' -" Y " ' Hifih'. x-: /.....•..'~ WeY-1'-' ~.~ '........ _: • y • ..--. --, I Hougl1land ~ Hill ",. 386 390 . 14 I 362 366 370 374 378 382 UTM east/west km Fig. 3. Blue white (Channell, 172.79 MHz) locations before (_._) the counts (---), and after (- ). Locations before (17 Mar, after (16 May, 25 t~ay, and 6 Jun 89) were determined by observation wing aircraft. the 15 helicopter counts, during 22 Jun, 10 Nov, and 16 Dec 88) and or telemetry from the ground or fixed1-- ~~I �f-' f-' co 4235~------------------------------------------~ Spanish Creek Rd E ~ s: ~ ?: i 3.:~.. 4231 .. ~.. .-..~ l o ~? North """ . Pass s 4227 s \._ 0:-, j ~ ~ '.q,_ _ - -. ?~ ~-;g. \~ -,.:" ~ Benny ~ ..\",~'~ <. ::> '., 4223- ~ Rllbbit~ C.'lh -IYo'!) 4219 I 358 I I • 0 . ~ ~O' (S) ~~ ~~ Campground t- ~~ Trickle ~ ~ountain "'- ua,:£!~_~.._~~'. ~tlOn -.-.._ •....•... "_" ~ -: \--:- 370 374 378 Houghland ( <, H'II • \' \\ I I 382 1::- _". \ /( ':'X'8/ U:-;-....:.:36~ I1I9hwa·-· . Y 111 7,10 14'· I 366 /"_"_"\~' r 11,15 <. 4: ~~. 5 2 9· I 362 / .A Buffalo Pass 'Il za a. O'(}~ ~~ _ ~ .•.... ..c 1:: ~C}f-. ~. '-"-> I I I " I I 386 I' .---- 390 UTM east/west km Fiq. 4. Blue orange (Channel 2, 172.81 ~1Hz) locations before (_0_), during (- -) the15 he l i cop te r counts. Locations before (23 Mar 88, 2 Apr 88, and and 6 Jun 89) were determined by observation or telemetry from tile ground or location during the 1st count was undetermined. Locations during the 12th and general area southeast of Trickle Mountain and are not represented with dots (numbered dots), and after 5 Jan 89) and after (16 May fixed-winq aircraft. The 13th counts were in the or corresponding nUlllbers. �4235-.---------- ----------------, Spanish Creek Rd ·"1-"> ~.. ~~~oo E ..:.::: s: ~ 8 ....... ..c 1:: 4231-1 North \00'00 '40f. ~ Pass \'_'" ....• ~ ?-- . Buffalo Pass 4227 s Campground 'i) I- "' .... ,"\ Cochetopa Pass ::> ?f ~Q' ~ ~ ~ ~ Benny ~ <S' C}.~ ':b,.>.' .'~ ••••... );;lckla ~ M~·h\in I) ."Guard •••.••, station '.' RllhJ..,. I I I I I 362 I I I I 366 r I r I 370 r r r r 374 r r}' I "-",1~ . \ $/ .. ...--'- • __ ._. ,111 J78 r r -, Houghla~d ~ HIli ··- D:nh ..~12·:\·?X·8/ .15 b llli;p 1Wa 4219 I 358 • • 4 5 ,,;,... 3' lj~. 2. •.•• ;-._ "VIr Cal1YOfl "--~.~;;;- I 382 I I I I 386 r ""'" I r I j 390 UTM east/west kIn Fig. 5. Blue square (Channel 3,172.86 MHz) locations before (_._), during (--and numbered dots) and after (dots not numbered) the 15 helicopter counts. Locations before (23 Mar, 3 Apr, 22 Jun, 10 Nov, and 16 Dec 88) and after (15 and 26 May 89) were determined by observation from ground or helicopter, or by telemetry from fixed-wing aircraft. Locations during the 9th-11th and 14th counts were in the general area of southeast Trickle Mountain and are not represented with dots and corresponding numbers. I-" 1-" .o �r~ Ij o 4-235-,------------------------Spanish Creek Rd E ~ s: -'3 ···l· .."..~... j 4231 ~ ~ North \"'" ~ Pass \._. 1:: s • .•••••• Trickle ~ 4 2 19 I "" VIJIC I , , I _"_. Cal1Yon , I , I 362 366 370 I I I 374 UTM east/west I ri;:;:--. . """'6 I I . .. 13-' 1·2 •• - •••••• / 6 /1 ~ Rllhl,.,. 'J • __ station , - _\-</'{ \ "' ~/~/,)./ ..~A~ •.. , ,~~·T ~/'>C·.......•.. ~.,., C::I Guard Mountain 4223 , \~ • .~Q' Benny :E .., ~ Campground 'Il () CD • v:~ ?- . Buffalo Pass 4227 358 Qf-.?a . ...•.• "5 ~ ••... s: ..'. {i ~ lOX ', /'/ .__:I.V Y l-fl~114 378 .~ .7/'1~/' I • "'_14,15 A ' Houghland \..:') HII ..••.•, . 386 390 I 382 km Fig. 6. Black A (Channel 4, 172.91 MHz) locations before (_._) the 15 helicopter counts, during the counts (---), and after (- - -). Locations before (7 and 22,Jun, 10 Nov, and 16 Dec 88) and after (16 May and 6 Jun 89) were by telemetry from fixed-wing aircraft. The location during the l l th count was in the general area of south Trickle Mountain and is not represented with a dot and corresponding number. �4235~----------~-----------------------------Spanish Creek Rd 4231 3_'''' .. · .., l ..!Ir::: =§ ~ 12 cL: "<, \ ~C}f-' 1:: s 2 :E • •••••• Trickle C) Mountain CClJ]YOf) 5' • .• _ ••_ ••:-;-......, ~ .{4 r II I II: ° \ RaM!.t / _. t II a.\y 1,,8 _""'{_ -_ _o 10 .,... ~\----rk/.(5~.........__~ ~ 5 "VOJIf ~-/ I I I 6"~\{ / I.:t( ~ Campground Benny •. / ~ '?Buffalo Pass ,"91415 13' 0' C} .._,-. s .•.... .c :?: o ~ North Pass E , , . • 1/ l\ X /' "-"_"\ . ~ ..._,;". -,. , .-\. Houghland ~ Hill "" Hi9hW8'-'-~ 421 9 I I 358 I I I I 362 I I I I 366 I I I I 370 I I I I 374 I I ,}' ,111'-r--r--'--·"---'-r---T 378 382 J86 I I I I 390 UTM east/west km Fig. 7. Black H (Channel 7,173.06 MHz) locations before (_._) the 15 helicopter counts, during the counts (---), and after (- - -). Locations before (7 and 22 Jun, 10 Nov, and 16 Dec 88) and after (16 May and 6 Jun 89) were determined by telemetry from fixed-wing aircraft. 1-' [ ..) t-·· �f-' '"'-.,j ,-' 4235~----------------------------------------~ SpanishCreek Rd 4231 3.''' .. · l ~ ~ .J::. .., ,..... 1:: i ~Q(. .. ..~...... ~.:--- 4227 Buffalo~~ •• · ~ CampgrolM~' ~ Benny • • ..•• . \. Q ~ :=! "'." -. \ ••••••••••••• ~ •• '1 t- ::> 4223 F/4 "- ~ bbit E ~ t l~ ~ ~,9 .... , · Trickle',," '\ "--- Guard ¥~mlain \. sr.liOi1 • ~~!. • s,\ .. -"-. ~(/" J 362 366 370 I 374 I J J ,111 378 .\" ~ f 15 any"" .•.•••.. - •• f.n~. 8-':~:· 'X6: / .,--.--_ , , , , , lVay--' 4219358 I , a. -5>0' G 'il 8 :n ~C}.~ o "''''' ~ ....•.. ..c: ~ o ..., North ." v. -.::: Pass •• -, . E s ~ 'r.:, \ ..~ I I Houghland W Hill ~ ", -, I 382 I I ,,----rI 386 I 390 UTM east/west km Fig. 8. Black J (Channel 8, 173.11 MHz) locations before (_._) the 15 helicopter counts, during the counts (---), and after (- - -). Locations before (23 ~1ar, 2 Apr, 7 and 22 Jun, 10 Nov, and 16 Dec 88) and after (16 May and 6 Jun 89) were determined by observation or telemetry from the helicopter, ground, or fixed-wing aircraft. The locations during the 2nd-4th and 12th-14th counts were in the general area south or southeast of Trickle Mountain and are not represented with dots or corresponding numbers. �4235---.-------Spanish Creek Rd /4231-0. ...- ..>.~ .._ -. I j E ..!:t.:: s: "5 g ••..•... ..c t g ;E I- ::l ~ '''\A' '" b" fT1P =. --..! Buffalo ).61ss" round ( Pass ~ ~ "v 0' Or. _'''-_ ,,-L -...~",~O' ~ \' <SI ~.~ ~ kl N-IC ~ M0J1l\altl l:'5~t'-.-.... Guard '," "., ,,/ / .._\_.., •• Sluuon ....___\ - -,.:1_ <1!)Yon n. -. ~ . ! <> / ~ ''\'.... "'- <,~ - ~ ,. c ' ,.A • . Rllbbit ~<l10 0 CampgrOllN~ ':;: ~, ~ Benny ,.,... 'Il 0 ( th -<l \ ..•...•.• '" ~ ~\ ~ North '\00'0 Pass \ _"'" • C7 "..___........J ~ ~ 0 \.. Luder's Cram 4227- \ ~ -~ .. _ .. _.. ~----,,- C) \--;. ;' ,/ ) .r /'/ 15 12. . '....... 113 8 6'~X' / / v,' •...•. ----~------- .' /' -... ( \~ \ r' I Houghland ~ Hill . <, Hin0 ...:_::. 14 / 4219 I I 358 ~/W8y , ,-.-. 362 , , , , 366 11-' ,-----.-.-.-,--.--'-,--'1-,-'1-1"--·-·1·-,-,---'--r-- 370 374 378 382 "'--'---'--"-1-,-'-- 386 390 UTM cast/west km Fig. 9. counts 88) and ground, south, numbers. Black K (Channel 9, 173.16 r~llz) l oca t ions before (-·-)the 15 he l icop tcr counts, during the (---), and after (- -). Locations be fo re (23 r1ar, 2l\pr, 7 and 22 Jun , 10 Nov, and 16 Dec after (16 and 26 May, and 6 Jun 89) were detennined hy observation or telemetry from the helicopter, or fixed-wing aircraft. The locations durinq the 2nd-5th and 9th-11th were in the general area southeast, or southwest of Trickle ttoun ta in and are not rcrresc>nted vii t.1I 'lots and corresponcling The 16 MilY, 26 ~1ay, and G Jun B9 l oce t i ons \t/(~re at the s arue si t c . ,_. ,. .) W �f-' Iv -I> 4235~--. Sp anish . Creek Rd 3.·r\ I E ~ .c t :J -o \ 2'~ COChetopac"t{ 11 ~t Beri //l 22 3-1 ::u a. ~\O'OI'{l~ ~ ••>. C) j ~Of' ~. ~iJI '.-. 4227 :'! o ~ " s I- ~ .., ~ North '" Pass '-.'. ~ .c ~ o 4231=i g ...•..• ?: <, -" 0>0' ~ ~ Buffalo Pass .~'% Campground \ ~ ~::s p" ny Pass o ~ " \ . __..-..: Trickle ~ Guard '\sta __..•.•..•. -e;. 00 ~\<--::t~.-.- '1~bbitCuf1Yon ----~ Mountain .•..•.... "-"-~-. • /ii,~ '.~ 15 .•.• "'--0. '. : .\) . /' ".- yI 1li2''':'''X »:' '\ Houghland \0 Hill . '" 8 Ohw~·-·-· 4219--,-r-.--r-,-.---J 358 362 r--r-;-r--r-r--y--,--,---,-,-,-,-,-.,-}',l~11---.-r-.--,----r--'--r-'--T-'--'----i 366 370 374 378 382 386 390 UTM east/west km Fig. 10. Black N (Channel 11, 173.26 MHz) locations before (_._) and during (numbered dots) the 15 helicopter counts. Locations before (27 May 88, 22 Jun 88, 10 Nov 88, and 5 Jan 89) were detennined by observation and telemetry from the ground and fixed-wing aircraft, respectively. Locations we re not determined during the 2nd-7th, 9th-10th, and 13th counts. �4235~----------------------------------------~ Spanish Creek Rd ~ 4231 . / ···l-·_)_''..+.., ~ o North '. Pass E ~ s: ~ :?:: ,. \ .•.•..... ~Q' Buffalo Pass Campground 'il ' Cochetopa Pass Trickle • VfJ1l: CC1!7YOI} 1 358 I I I C) Mountain Rllhk'-' 4219 I Y("/'-"-'\~ Benny ~ ~ I 362 I I I 1 366 x: a. ~C)..~ ..,.". .....• <-- s 4227.c t s i '4~. I 1 I 1 370 I ..,.. •• _.. •..•.. I . .' ~5 .!1 - .. ' 8 ~~ Houghla~d """'" ~ HIli ••~' "X"/ Hi,:-:-"""" 10 • Ohw(l·-·_· I I 374 I I . I }' ,111 378 I I 1 382 ,----o-r----r----r--r--r--.. 386 ,390 UTM east/west km Fig. 11. Black P (Channel 12, 172.84 MHz) locations before, during, and after the 15 helicopter counts. Locations before (5 May, 22 Jun, 10 Nov, and 16 Dec 88) and after (15 and 26 May 89) were determined by observation from the ground or telemetry from fixed-wing aircraft. Locations during the lst-3rd, 6th-7th, 9th, 12th-13th, and 14th-15th counts were in the general area of south or southeast Trickle Mountain and are not represented with dots and corresponding numbers. ,__. I J UI �t-' 10 0' 4235~-----------------------------------------~ Spanish Creek Rd 4231 ~ .c ~ ~ ••..... ..c 1:: .. /· · 3,~ l . J o 4227 '. \,~ '. ~Cf.i> s <) 'b., ~O' ~ ~ss~ ~ ....' '\ ~.~~...... 5 '" 4223 RaN.> ..,jf , 358 " I , I Gu~rd'~~J~ •••••••• , I I I 362 366 370 '. ii[j;--'i";3'x:'/"~ WaYl-' Houghland \0 Hill .._ .••_. - I 374 I .-"- 'Y , 4'112 stl!tiOll_ ilIIyO!} ~J(/"/ "\~ 1\ ~ • Trlcl$'''' \____ ;'- E ~ , '" x: o, q.~ ~ "').. Buffalo ':) Campgroul\d ._. ~ nny • Be , ,~, V~ ~ 4219 I i ~'" North " Pass '" E ~ •_'I' , .13: 5/" I I I 378 11- -r1~1- 382 ~\ \ I I -,--~I 386 I -, '. I I 390 UTM east/west km Fig. 12, Black R (Channel 13,172.89 MHZ) locations before (_._), during, and after (- - - ) the 15 helicopter counts, Locations before (23 Mar, 2 Apr, 7 and 22 Jun, 10 Nov, and 16 Dec 88) and after (16 May and 6 Jun 89) were determined by observation from helicopter or ground, or by telemetry from fixed-wing aircraft, Locations during the 1st, 9th, and 14th counts were in the general area of northnortheast, south, and south Trickle Mountain, respectively, and are not represented with dots and corresponding numbers, �4235~----------------------------------------~ Spanish Creek Rd o / · ... .. .., 4231 ···.1··>."" ~ s: '1.:J ~ North Pass 13 ~ v-,v-, ",. \ 5 C}f-.s.~\/'K~ .. .....•. "",- s 4227 t s 9 /....:~~3,4 <- ••.•..... / Q .t::. Buffalo Pass ~ Campground Benny %.;:s / / / , ;! '~~, ' -, 'rO" \,(\ <:»: • .)a., ' , I~ \' ~\ \ ~. _ ~4_- ~ •. 1,2 'il 11 ."","-' 5 C·/ .-~.- ..~ 1• uard Moun~4n .1JtQ1 station 10 G '.:"1' -, • ITlllu..,. CanYon 421 9358I , ' , , , , , , , ....• ~I I I "'IJfC I 362 366 I 370 ..- ,:0;;;--. ,: / ..~ i I Iii i 374 378 UTM east/west ). . X W8Y-l ._. I '1 iii 382 Houghla~d \0 HII "'. . i I I I 386 I iii I 390 km Fig. 13. Black S (Channel 14,172.94 MHz) locations before (_._), . .r i nq (----), and after ( ) the 15 helicopter counts. Locations before (7 and 22 Jun, 10 Nov, and 16 Dec 88) and after (16 May and 6 Jun 89) were determined by telemetry from fixed-wing aircraft. Locations during the 6th and 7th counts were in the general area northeast and southeast of Trickle Mountaili ud are not represented with dots and corresponding numbers. I- ~'-' ,.J �t-' I·.) OJ 4235--,------~ Spanish Creek Rd 4231~;31'_'..' , .. E ~ North P ass .!r::: .s: ~ 8 •....... ..c t 14 Ludsr's CreEk 4227 Cam::>around s '. '-. \ ,,-y' 13,." • I- Buffulo Puss 4223- Pass Guard station R~bh:4. Vir 4219-~ 358 CanYon ~ ~<, 6 r ,)( / ~ <, ~ • /'~\~ ~J$>O' ~:::s COChetopa( ::> / , 0~/ v ?-- \ •• th", ..~....•.... -," •• 9 •• , i1q~ , '\) Campground Benny ~ ,.. " / 8 \ /12 -.l1. 1,,57 . »<c: Trjckl~ ~ ..,:;;~1f.j~;/,/ -:-..:. ~ Mountain." ,..'~#._.\ . ~ ~_ .7///1 • .--~ -"- / t/ 2 ;;;:•...~ I \ •....... .(/~ .• ~ . X1oh/ lii9hwp' -._./ ~)t •. \ \\ Houghland ~ Hill 366 370 374 378 . 111- I 362 "" 382 ,- 386 390 UTM east/west km Fig. 14. Black T (Channel 15,172.99 t·1Hz) locations before (_._) the 15 helicopter counts, dur i nq the counts (---), and after (- - -). Locations before (7 and 22 Jun, 10 Nov, and 16 Dec 88) and after (16 t~ay 89) were determined by telemetry from fixed-wing aircraft. The location during the 11th count was in the general area of southeast Trickle Mountain and is not represented with a dot and corresponding number. �4235~----------------------------- / 3_.".. 4231 Spanish Creek Rd -I" E ~ :§ 8 •........ ..c t • ~ o i ".•.. " -t .••, North .. ,. Pass ~ . _ ~ ~" -x -s-, ~ v' ••_. .t:-." ••••, .••, ,..-..!. 4227 s , q" -, Buffo!~~ 0iJI."". ~" ass .'~"" . '" CamPll<. ,_ ~ r :J Benny ' ,' ,.'~..••. •'\ R. 4219~~~~~~~~~~~~ 358 362 366 370 )' // / / :l'''cklainc,/ / // 15, Mou!l)a / 374 ltii1>waj7i r I I 378 / _"-'" "', \ ,, r \:" / •.•.••x •••..•.. // /" .' r>, ,., ~.~ '~~::::~ abb;r CiJI)yon / ~ .', ~ "/ • • . Pass Q~ x: o, : _~," Houghland. / 11', , , '-'T:;-8 6 382 __/ . ., ,) 9 () '- UTM east/west km Fig. 15. Black U (Channel 16,173.04 MHz) locations before (---), during (---), and after (- - -) the 15 helicopter counts. Locations before (23 Mar, 2 Apr, 7 and 22 Jun, 10 Nov, and 16 Dec 88) were determined by observation or telemetry from helicopter, ground, or fixed-wing aircraft. Locations during the 1st, 5th-7th, 10th, and 12th counts were in the general area of south, southeast, and southwest Trickle Mountain and are not represented with dots and corresponding numbers. ,_. I·.) '-D �I-" W o 4235~------------'------------------------------~ Spanish Creek Rd 4231 E ..!a::: 3... ····· l . ~ Ludsr's g o '~"\ North ", P!Ie~" ~. .c :?: or R' .•..•• CrB~ \ -e s ~ b'.-"&' a"i~"""ss-- 'il ~ Camp13rp'tna: Benny ~ ~ ~ () •.•...••........•• ~0·.. .. ~ C arroaround .c ~ijI .....•. ".._"".. U'C}~ , ~ 7'.... '. ~ ..•.•. ~ '-: ·'~, \ 't>: Trickle ~ •~·i ~ountain "". • Guar•d...... •. 4219- _ .._. 12 • ~C_)l.!.9:~:='.15 __ -.j ".' • -"_" a. "'-y." ..(.. !/'...... '\~ •. ~ . 5 4' Rllbbit~' Ca17YOf) t» ~Q' ~ (SI ,........ !:i i ~q. <- 2 ro iX' /' k~._._. ~ •• •. ..', ~ - - - --'_' --r-H;ughland ~ Hill ---'- "'" '-'-~~'-'-~~-'-'-'-'-'-'-'-'-'II~.-rY-Tl~11-,,-·~~~~~~ 358 362 366 370 374 378 382 386 390 UTM east/west km Fig. 16. (- - -) and after aircraft. southeast Black female (Channel 17,173.09 MHz) locations before (_._), during (---), and after the 15 helicopter counts. Locations before (17 and 23 Mar, 7 and 22 Jun, 10 Nov, and 16 Dec 88) (16 May and 6 Jun 89) were determined by observation or telenletry from helicopter or fixed-wing Locations during the 1st, 6th-7th, 11th, and 13th-14th were in the general area of south and Trickle Mountain and are not represented by dots and corresponing numbers. �4235 \ Spanish Creek Rd ~ 4231 8 .••... .c 1:: -"-i··f _'."..".., North Pass E ..!&::: .s: ~ . ~ '. ~ ~ o ,.\ i '"\ '.-'. ..•.... \ 2'-Buffalo Pass 4227 s Campground 'il Benny ~ ~~~0f-~C} Q ~ ~ ~~ ~ ~ Q '\ . ~ ~ %~ \ .• ! t- ::> \ 4223 358 Trickle () 'i• •••••••••• ~.- •• -.. 366 370 374 UTM east/west Fig. 17. Black X (Channel the 15 helicopter counts. 6 Jun 89) were determined were in the general area numbers. NJ/ ~ i-» ~~ 6 / .... / I/// -·12/ / 'r_;,~;Z'!:~ »>' P:1_/~ ..•_.~. Hi9hW8. _._ }' .. • /8 ~7 /;1'\ x-...?: /_/ \\ ,91415 "Houghland \0 Hill .3/ 1 1 1--.--,-.-1-.-. 378 1,2 \;;... ~..".(~~ ~ ~<T "/-.tJj_'!I- .J" "~ y/ Y''''' Mounta!n.:.:": ~/ " 4· ~ -~-r--r--Y--Y--r--r---r---r--r--r---r--r----.---, 362 ~5._.. ~. //;. Guard t::l ~~ : '\ t r 1711bbit .••... ~.-/'~_!!.lOn Caf1YOf) 4219 x: a. 382 386 "\ .. ~". . "" r--,.. ---r---,-- 390 km 18,173.14 MHz) locations before (---), during (---), and after (- - -) Locations before (7 and 22 Jun, 10 Nov, and 16 Dec 88) and after (16 r>1ayand by telemetry from fixed-wing aircraft. Locations during the lOth and 11th counts southeast Trickle Mountain and are not represented by dots and corresponding ~w r~ �1-' W 1'0 4235~------------------------------Spanish Creek Rd 4231 E ~ ?: 3·\ "~ .. , .c ~ 8 4227 " t .c I North Pass or o \ ~ Campground Benny :E t- :> 4223 Trickle () Mountain Rdb&t~\ ~ . Guard ~tlOn 366 370 . I? .3. . r;J 8 .; ".! :.,,~ ..' ~ ·.••..··;:h.-··-·.~I?.2:_./ C""YOI) 362 ~~- ~'j .. .",.,. ..•........ Cochctopa( Pass : 4219358 c: '>t .f0' -"~ 2-BUffalo Pass /' <> 0. oJ q"{k, ~..x " -' :lJ ~, ..~. 'V i '4Qf-. '. ..•.... Luder's Crsek Carroaround s ~ \l Hi{J/}lVdy 114--- 374 378 1----~ <, ./ '\ .-'-. Houghland ~Hill _ '--'"38-6' "" _,---,_~~ j 90 382 UTM east/west krn Fiq. 18. Black Y (Channel 19, 173.19 MHz) locations before, during, and after the 15 helicopter counts. Locations before (3 Apr, 27 May, 7 and 22 Jun, 10 Nov, and 16 Dec 88) and after (15 May 89) are not differentiated from the helicopter count locations because of the tigllt cluster. Locations during the 2nd, 6-7th, 11-12th, and 14th counts and the fixed-wing flight of 6 Jun 89 were in the general area of soutll or southwest Trickle Mountain and are not represented with dots and corresponding numbers. �4235~-------------------------------------------~ Spanish Creek Rd ~ 4231 ·"~l··>_'\.~.... Pass 15 "-t ..c ~ . 0 ~ / ........• /9 cc. '-." ""'T 'lIJr -$'", TrickJe tl Mountain 4223 58 , ' ' !YO!) 1 j j I j I •••••• _ .,-..' liiih'. j j j j 362 366 I' 370 . 374 j I r 378 11 V ;,).0 • •. -/-.(.-(~ ". ~ / ~,<..,:.-" ' .15. X I " ~". lOV, ... \ /' J~ ""8Y-1'-' j I 3 .' . »«: /~""""6 13' .,,.-- Benny s 4'''' Q ..---- .....•. ~,,7 y.... , .<\ •.• Buffalo Pass ~ Campground :E 'y, ,..---81112 ,..f.3 2'-- 4227 s i' 5 North '\ .• E ..!II:: .c g . / Houghland • j j 382 \0 Hill I I r I 386 I ", _.~ I -, I I I 390 UTM east/west km Fig. 19. Black Z (Channel 00,173.21 MHz) locations before (_._), during (---), and after (- - _) the 15 helicopter counts. Locations before (7 and 22 Jun, 10 Nov, and 16 Dec 88) and after (16 and 25 May, and 6 Jun 89) were determined by observations from ground or telemetry from fixed-wing aircraft, t-" W '-'-' �r-' W -1-' 4235~-----------------------------------------~ Spanish Creek Rd 4231 E ~ 3"" .. ·, l ~ ?: a (j) o j .. North Pass ", \ ~ :0 ..""". 8 •....• ..c '?- Buffalo Pass Campground 1::: s Q.. 'il 13' Benny ~ (jp/ I- ::> Trickle (:) Mountain 362 366 370 374 UTM east/west 8/ :'//i ~ -"-"~ T •• { i~.•..... 15 Hi9hWa' - 421 9-358 ./~ ,. ~ 6.>f.·,?:14 tf'1 •••••.••• 1/ \,.' - ~ .' Rc')blw~~n Cal1YOI) i :(1/12 •• _. }' 378 .:»: . \ Houghland \0 Hill '-. "" 11-1-,--,-r-r---r--r-r-T-T-r-r- 382 386 390 krn Fig. 20. Red dot (Channel 10,172.51 MHz) locations before (_._) the 15 helicopter counts, during the counts (---), and after (- - - ). Locations before (22 Jun and 16 Dec 88) and after(25 May 89) were determined by telemetry or observations from fixed-wing aircraft or ground. Locations were not determined during the 2nd, 5th, and 10th counts. The location during the 11th count was in ttle general area of southeast Trickle Mountain and is not represented with a dot or corresponding number. �4235 Spanish Creek Rd 3 / · l ~~ .. , 4231 ~ North Pass E ..!x: s: A 15 g .•....•. .c -e .. l.uder's Craffi 4227 s ~ "<, \ ..__,-. i o """ ~CIL '1.' ~. '?_ Buffalo Pass ~ Campground Benny t- I --j \ ~.A' Ii>' . ~ 7,13 : ~ ~ ~ ~ ~ / Q'/ -:! ~ ~.;:s / / '.'. / '4 , ?' )", ...._~·/~~11~ ..-.-"'-:-.x'r.::. . .• , .. """ x._( /~ • " ~~. "/ ,." : ..•_ .. _.. -~-.-.-,,- .. /\) 11 / '\ __ l11-r--'-~ 4219- R'-~~~1I-:;;'7"""""-r:::T'-'-'--'-...-r~Hh~~n~~~. ~ 358 362 374 366 370 378 382 UJ1Wll';-'. 10 »:»: •. • 8,12 "~" . ~ / ~1·~· ~ Rabbit C al1yon ~ 119~ 0' C}: Trickl~ ~ Mountain ::> 4223 ~ J . L ~.~ Houghland ~ 386 Hill "'. . m UTM east/west km Fig. 21. Red 1 (Channel 11,172.54 MHz) locations before (_._), during (---), and after the 15 helicopter helicopter counts. Locations before (22 Jun, 10 Nov, and 16 Dec 88) and after (6 Jun 89) were determined by telemetry from fixed-wing aircraft. ~~ l,-J UI �t--' W Q\ 4235~-----------Spanish Creek Rd ~ (j) 09 .., . 4231 ~ ~~. 0' E ..:.:: s: ::J s 4227 s a 4 .,.~~ .•.•.. .c 1:: t- ::> Trickle Mountain /{ ,'{J_ 1 1 I'/ <::) RlJN,.", VUfC CanYon ~'" - , ~( staten ......... A_ .._ ..~ /' •... 1 7 '~ ~ 4219-1 358 II I .:..l4- 6 I__ ~~ 8~\ .'3 . 131. I ~ 5· -_ II IO'l' \ :~ \ .. \~ . ~ (\\ \, .._ _ •.- -" ~~ -...•..•....;.. ....." --.,....-------.;:....: ... 14 : .1 ~1,2 ...-~. Houghland ~ Hill "" Hi9hWa'-'-' y 111'-r--~ 362 366 370 374 UTM east/west 378 382 .,----,- 386 --.----. 390 km Fig. 22. Red 2 (Channel 12,172.56 MHz) locations before (_._), during (---), and after ( ) the 15 helicopter counts. Locations before (22 Jun, 10 Nov, and 16 Dec 88) and after (16 May and 6 Jun 89) were determined by telemetry from fixed-wing aircraft. �4235~-------------------------------------------~ Spanish Creek Rd ~ g: (j) 4231j ~'~" E .!I:: s: ~ ~ .•.•... .c. 1::: .. ~ North o , ~ "'" \ Pass 4227 g ~...0 ~\II "-' 2'-- . <) ~~ -r-~ ..•... Buffalo Pass Campground 'Il ~" Benny ~ ::> 5,9 35 8 '" 362 4 21 9 0- ' /3/\ \ ~O' 2 ~ 11 "Y On I \ ~,1 li \/' /.v'( I " •. 'l/·x \. Trickle ~tI, _I.I. /, M \ '" '-... Cdh I ')" _ .....• \ a. <J'q.~ -0> ,......... flabbit~ I , . ... :IJ :10, I- 4223 ,_ i ~Qf' <:~' 136 6' 1 I , ' I 370 ~6' :ouar(l"ounla~ station 7"', \ . ••••.•. 12 I I _' I 374 <, ~(" Hi(;;;;:.8Yl'_' 15 /' 1"\ I \';)~ V /'~ 378 11 382 I •._ .. " : \ I "_" I /'_ I ' 'I Houghland \0 Hill -~ -. -, r-,--------,-- 386 ,)90 UTM east/west km Fig. 23. Red 3 (Channel 13,172.59 MHz) locations before (_._), during (---), and after ( ) the 15 helicopter counts. Locations before (22 Jun, 10 Nov, and 16 Dec 88) and after (16 May and 6 Jun 89) were determined by telemetry from fixed-wing aircraft. .W -.J �I-' ,,) rx: 4235~------------------------------------------~ Spanish Creek Rd 4231 15 t \.. Pass ..c 8 3 ···",· l .. iD o North '\ .. ,. E ~ ........ ..c :?: [ \ x: Q. O'q.~ ".,- .......• t)lQ' 2"-Buffalo Pass 4227 s ~ '4Cf· \) Campground Benny ::::=! I- ::J 4223 =. TrickleC) Pass R~bM<, ~ uit allYOII 66 4219358 362 E ~ 3 • --- Guard Mountain .1';1 ~(// : '1station ~_ •• -.'- • •• ·A F HiOh'~:13.'8/· ~ I: ••_ ••.(4; "'5 ..~~X.J 370 IVaYI'-' 374 378 11 382_ ..\';)~ t, " A Houghland \..:)Hill -, -. ~I·--'---'386-'--' 390 UTM east/west km Fig. 24. Red 4 (Channel 14,172.61 MHz) locations before (_._), during, and after the 15 helicopter counts. Locations before (27 May, 22 Jun, 10 Nov, and 16 Dec 88) and after (15 May and 6 Jun 89) were determined from observation from the ground or telemetry from fixed-wing aircraft. Locations during the 1st, 3rd, 7th, 9th-12th, and 14th-15th counts were in the general area of south or southeast Trickle Mountain and are not represented by dots and corresponding numbers. �4235 Spanish Creek Rd 3 / · "I"~ .. 4231 .. ~ North 'v., E .!o:: s: ~ '-. Pass \ .....-. ...•.. s ..c 1:: s ~ ~ o <fI 'il ~ I- 4223 I ~ • " - ,~ Cl t(", -~./ "_~ountain station " -.11 CanYon -j ~ s·, "., . _ .. _.. d·:.X .. __ H'",~1.14 _ 4. 362 Trickle Guard \ Rltbb;t 4219 358 ~Q' .~ ~ Campgr~" Cochetopa Pass ::> 366 CI.. •... ~ &1tfaIQ fass Benny :::0 U'C}.~ 0 ij) . ?- ••••..... ~ ~~. ~ 370 - 374 UTM east/west IS : 8" / -"_" .. \") .c.>:' ·K. ' .-~ . Hougtlland "" ~ Hill '~JWLl,;-,_. ~J 11 378 1 '382'"386 y)Q~ km Fiq , 25. Red 5 (Channel 15, 172.64 r~HZ) locations before (_._) the 15 helicopter counts, during the counts (numbered black dots), and after (- - -). Locations before (10 Nov and 16 Dec 88) and after (6 Jun 89) were determined by telemetry from fixed-winq aircraft. Locations during the 2nd-7th, 9th-lath, and 13th counts were in the general area of south or southeast Trickle Mountain and are not represented with dots or corresponding numbers. The location on 6 Jun 89 was in Saguache Park about 19 km off the map to the southwest. ,_. w -0 �,_. +-' o 4235----r--------- .-----------------, .SpanishCreek Rd 4231~31'.'.'. ~ .J::. ~ 8 •....• .J::. t or o .., North \", Pass E ..:.: . -, ~ \ Cochetopac I- ::> U" _-' '.~~:-...r ,~. 'V Campgrouncr, nny ~ 358 1 I''. .-$>0' ~ ~ T .•k1-' ~~ .....• ~rJc ../ ..- ..- ..'\-:'l a () ( ~!1 ~ ountai1 • 'I -OUl!l!Q. - _ .8 Can 1 362 _"" ~ .'Yon -+-'-1 ~($) --.- ~- \ Rabbit 4-2 1 9 •• \\~~. ~~~, Pass 366 370 x: a. O'q.~ •• .- '§:.__ -->-.." ~ ~ 13 15\ Carrooround s :-..~ "-'.~~. 14 ~ ~('f' ..•~ ~r. Luder's CreEl< 4227 ~ g: . \\ ;tatk>n '~-..., . - .. :-;--....... • 1ii00W8.·l_ ._ . Y 111 374- 378 .' \ : './2 .-'- I .' \) / '\ 1 1 »> '..... Houghland ' . (,- HOII • "'-.-> I 382 I ,-r-l-r-r-T-r---,-- 386 390 UTM east/west km Fig. 26. Red 6 (Channel 16,172.66 MHz) locations before (_._), during (---), and after ( ) the 15 helicopter counts. Locations before (7 and 22 Jun, 10 Nov, and 16 Dec 88) and after (16 May and 6 Jun 89) were determined by telemetry from fixed-wing aircraft. Locations during the 1st, 3rd-4th, 6th, and 9th counts were in the general area south, southwest, and northwest of Trickle Mountain and are not represented with dots or corresponding numbers. �4235~------------Spanish Creek Rd 0l"~" 4231 ..._.f '. i ~C}f-. \ .:u ~.:.., ~ .•.•... .c Buffalo ~~S ~ Campgroun~ • Benny g ~ ~ / a. O'(}~ Q \.~~ s 4227 t: o ~ Pass 1.:i fl (j) .~ ~ North"". E ~ .c: s: -$»0' ,'"i. ~.~, '\ l--_______' X M~ain Guard· station .\ . 11 ._ .._ Rabbit ~ CanYon 5 •...• 2 12· . 14158 .~ \ . .~.~ • /' Houghland ~Hill --'- '<,-, Hi9hwa' - ._ . 4219 I , 358 J J J J 362 J J J , 366 J I J , 370 J J J J 374 J J J:.Y 1 ,11 378 J J , 382 J , 386 390 UTM east/west km Fig. 27. Red 7 (Channel 17, 172.69 MHz) locations before (--.--), during, and after the 15 helicopter counts. Locations before (22 Jun, 10 Nov, and 16 Dec 88, and 5 Jan 89) were determined by observation from the ground and telemetry from fixed-wing aircraft. Locations during the 1st, 3rd-4th, 6th-7th, 9th10th, and 13th counts were in the general area south or southeast Trickle Mountain and are not represented with dots and corresponding numbers. ,_. .... .1> ��l'4J~ Colorado Division of Wildlife Wildlife Research Report July 1989 JOB PROGRESS REPORT State: Colorado Project No.: W-12S-R-2 Work Plan No. :__~2~A~ Job No.: Author: 5 (supplement) Mammals Research _ Mountain Sheep Investigations Computer Simulations to Statistically Evaluate the MarkRecapture Method with Mountain Sheep A. K. Neal Personnel: A. K. Neal, G. C. White, D. F. Reed, R. B. Gill, J. Olterman ABSTRACT Monte Carlo simulations were used to evaluate the mark-resight method for estimating population sizes of mountain sheep. Specifically, the precision and bias of the estimates were assessed given violations of the assumptions of mark-resight. With sighting probabilities changing on each flight, the variability and the bias are greatly decreased. With heterogeneity in individual sighting probabilities, the confidence interval coverage of the estimates is too low. With decreasing sighting probabilities over time, coverage is much more variable. With groups of animals, the estimates are more variable, coverage is poorer, and overestimation is a problem. This Job Progress Report represents a preliminary analysis and is subject to change. For this reason, information presented herein MAY NOT BE PUBLISHED OR QUOTED without permission of the Director. ��1:;5 INTRODUCTION Mark-resight, a method based on mark-recapture (Caughley 1978) with a Lincoln-Petersen estimate (Petersen 1896, Lincoln 1930), is one procedure to estimate the size of mountain sheep (Ovis canadensis canadensis) populations. This method involves first capturing and marking the animals, and subsequently recapturing or resighting them. Identifying and counting marked and unmarked individuals then provide estimates of population size. Quantitatively, the basic estimator of population size (N) with one marking occasion and one recapture or resight occasion is N (equation 1) (m2) where n1 - the number of animals initially caught and marked, n2 - the number of animals caught or sighted in the second occasion, and m2 = the number of marked animals caught or sighted in the second occasion. However, this estimator becomes more biased as sample size decreases (White et al. 1982:18) and may be corrected when (nl + n2) > N by modifying equation 1 as follows (Chapman 1951, Seber 1982:60): (n1 + 1) (n2 + 1) -1. N (m2 + (equation 2) 1) Bias is defined as the difference between the estimated and the true population sizes. The associated estimated sampling variance is: (n1 + 1) (n2 + 1) (n1 - m2) (n2 - m2) var (N) (equation 3) (m2 + 1)2 (m2 + 2) (Seber 1982:60). When using this method, several critical assumptions must be satisfied to estimate abundance accurately (i.e. with good precision and without bias). The first assumption states that the population is closed demographically and geographically. No individual may enter through birth or immigration, or leave through death or emigration; given only one marking occasion the proportion of marked individuals must remain constant. This assumption is rarely met in a natural population, but its effects can be minimized (e.g. by shortening the time period between marking and recapturing). Some models have been developed incorporating deaths and migration (Seber 1982, Seber 1986). Kufeld et al. (1987), using radio-collars on mule deer, determined which proportion of marked animals were in the study area at any given occasion and thus maintained a "closed" population. A second assumption of the mark-recapture method states that all animals (marked and unmarked) have an equal and constant probability of being �146 captured and of being recaptured or resighted on subsequent occasions. Animals that are captured on a given occasion should not be more or less susceptible to being recaptured or resighted than others. In a study where animals are recaptured, if heterogeneity in capture probability occurs, the estimates can be significantly biased (Otis et al. 1978:11,25,30,34). In a study where animals were sighted twice using two observers in one plane, Pollock and Kendall (1987) reported heterogeneity in sighting probability led to negative bias in the estimates. In a study where animals were live-captured and marked and then "recaptured" by resighting from the air, White and Garrott (1989:275) reported that capture heterogeneity was avoided with one method of capture and a different method of "recapture", and that individual sighting heterogeneity did not bias estimates of population size but did underestimate the variance. One explanation for this heterogeneity in probabilities may be disproportionate marking so that marks are not randomly distributed among the animals but one segment of the population receives a greater proportion of marks (Rice and Harder 1977). Alternatively, the researcher may not be able to regulate heterogeneity of probabilities because trapping probabilities and reactions vary per individual animal. A third assumption states that samples are random. To meet this assumption, either the capture or the recapture effort must be randomized. This assumption is violated if one animal's probability of being sighted is not independent of another's (i.e. animals form more or less stable social associations). If marked animals are not randomly dispersed throughout the population and are accumulated in higher densities around the initial trapping areas, traditional variance calculations are not valid (Kufeld et al. 1987). The variance of the estimate increases with clumping (Rice and Harder 1977). Researchers have little control over this aspect if the animals being studied characteristically band together. If groups tend to be randomly distributed, then groups can be counted and mean group size (number of animals per group) calculated separately to reduce the bias and still get an estimate of abundance (Bergerud and Manuel 1969, Eberhardt et al. 1979, Seber 1986). A fourth assumption states that animals do not lose their marks. If they do, a greater proportion of unmarked individuals will be counted in the population than is actually present. A final assumption states that marked and unmarked animals are correctly identified, counted, and recorded. The observing and recording must be precise and unbiased. These assumptions are often violated in real-world situations, resulting in biased estimates. Population demographics change, capture and sighting probabilities differ per individual, animals group together, animals lose their marks, and recording errors are made. In an open population with recruitment and mortality, the estimate is too high (Otis et al. 1978:10, White et al. 1982:3). Carothers (1973) noted population size may be underestimated when probabilities of capture �differ. Eberhardt (1969) reviewed several studies, noted the bias involved with unequal capture probabilities, and suggested revision of trapping methods (i.e. randomization of trap locations and shifting of traps) and modification of the Lincoln Index ( i.e. N - (nl + nZ)(nl + nz - mz) /2mz where variables are defined as previously). In contrast, Magnusson et al. (1978) felt that violations of the equal capture probability assumption will not bias the estimate if the probability of being marked and recaptured are independent and based on beta distributions (i.e. where capture methods differ from recapture methods). However this condition will only apply to populations where capture methods differ from recapture methods. In regard to sighting probabilities, Strandgaard (1967) observed that variations in behavior of individual roe deer affected the animal's likelihood of being sighted; consequently the estimate was depressed. Little research has been done with regard to clumping, however Quinn (1980), using schooling populations of fish, provided a mark-recapture estimate accounting for clumping given specific marking schemes or population characteristics. Interactions of these violations of assumptions result in an estimate that is biased, imprecise, or both. In addition to problems associated with violations of model assumptions, the mark-recapture estimator is influenced by the number of animals marked. For example, given a single marking session, Bartmann et al. (1987) recommended that at least 45% of a mule deer population be marked in order to achieve a reliable estimate for small populations. In a study where roe deer were marked as they were caught, Strandgaard (1967) concluded that at least 66% of the population must be marked to obtain estimates that were acceptably precise and unbiased. The number of recaptures or resightings can also influence the estimator. Improved estimates are achieved through multiple recaptures or resightings. Schnabel (1938) and Darroch (1958) described this method of mark-recapture with mUltiple recaptures. At each recapture, the proportion of marked animals was recorded, unmarked animals were marked, and all were then returned to the population. The proportion of marked animals over all recapture occasions was then used to estimate the population size and variance. Rice and Harder (1977) used a similar multiple recapture method with white-tailed deer but did not mark after the initial marking because resightings were done via helicopter surveys. These researchers emphasized the importance of multiple resightings to strengthen the population estimate by increasing precision. When all animals caught in a single capture occasion are marked and recaptures result from multiple resightings, separate Lincoln-Petersen estimates result from each resighting. These individual estimates must be combined to obtain one overall population estimate, and the estimator chosen also affects the accuracy of the estimate. The joint maximum likelihood estimator from a hypergeometric distribution, or JOMLEHD (Chapman 1951, Seber 1982:59, Seber 1986, Bartmann et al. 1987), possesses the optimal properties of any of the estimators. Bartmann et al. (1987) and White and Garrott (1989:273) noted the advantages of this �148 estimate over the mean or the median: the variance is minimized, the confidence interval width is narrower, and the lower confidence bound is never lower than minimum number alive. Using JOMLEHD reduces bias and increases precision of the estimate (for definitions see White et al. 1982:18-19). Specifically, White and Garrott (1989:273) and Seber (1982:59) define the maximum likelihood estimate (MLE) as the value of N where the following is maximized: k+l IT i-2 [ ::] [:,::: 1 (equation 4) [ :, 1 and the terms are defined for all i - 2 to k+l number of sightings. This estimate can be found by iterative numerical methods. Aerial mark-resighting methods have been used to estimate numbers of free-ranging mountain sheep (McQuivey 1978, Leslie and Douglas 1979, 1986). By using one method for capture (e.g. drop nets) and another for resighting (e.g. aerial surveys), confounding factors (time differences, animal affinity or aversion to traps, and individual variability in these reactions) are eliminated (Otis et al. 1978:11). While flying, a helicopter, instead of a fixed-wing aircraft, allows greater maneuverability in the air and optimum airspeed and height above the ground (Seber 1986). However, questions about the effectiveness and accuracy of helicopter mark-resighting methods exist (Furlow et al. 1981, DeYoung 1986). When using the hypergeometric model (sampling without replacement), animals, both marked and unmarked, cannot be counted more than once (Rice and Harder 1977). Visibility bias can lead to erroneous population estimates (Pollock and Kendall 1987). If the collars or marks make the animals more conspicuous to the observer, the population will be underestimated because unmarked individuals will not be noticed as readily. Alternatively, Bear et al. (1989) overestimated an elk population when marked animals were misclassified. Packard et a1. (1985) noted that habitat, weather conditions, and observer experience can all lead to an underestimation of population abundance. Floyd et al. (1979) in studies of deer and Samuel et al. (1987) in studies of elk examined the effects of observer bias and evaluated the effects on counts of observers, changing ground and weather conditions,and different cover types. With moose, LeResche and Rausch (1974) noted the inaccuracy of the counts given observer experience, number of observers, snow conditions, habitat and terrain, and time of day. Finally, Caughley (1974) listed several factors that can affect the observer and the probability that an animal will be seen: thickness of cover, background, lighting, animal's color, animal's movement, animal's size, observer's eye sight, level of fatigue, speed of travel, altitude, and strip width. �149 Because this method of mark-resighting, with one marking period and multiple aerial resightings, is used fairly extensively, the estimator of population size should be precise and unbiased. To date, few studies have mathematically assessed the extent of problems inherent in this method. To improve estimates, the mark-resighting method needs to be evaluated quantitatively with simulations, using realistic data. With a known population size, the effectiveness of JOMLEHD estimator and its robustness to each individual assumption need to be simulated and tested. Similarly, violations of the assumptions need to be simulated and tested with populations of known size. METHODS For all sets of simulations, the precision and bias of the JOMLEHD estimator were assessed using known population sizes, different sighting probabilities, different capture probabilities (proportion of population marked), and different numbers of sighting occasions (flights). The Statistical Analysis System (SAS Institute Inc. 1985) was used for Monte Carlo simulations. Population sizes of 50, 100, 200, and 500 were used with 5, 10, 15, and 20 sighting occasions. Capture and sighting probabilities were assumed to be equal and constant for the whole population and were assigned values, respectively, of 0.1, 0.3, and 0.5, and 0.1, 0.3, 0.5, and 0.7. For each simulation, the number of marked and unmarked animals, and the number of marked and unmarked animals seen per flight were generated as random numbers from the binomial distribution. The number of marked animals was restricted to be greater than or equal to 10 and less than 80% of the true population size to simulate reasonable expectations of actual field trapping occasions. For each simulation, a JOMLEHD estimate, the 95% lower and upper confidence interval values, the confidence interval length or CIL (the difference between the lower and upper confidence interval values), and the coverage of the true population size by the confidence interval (above, below, or covering) were then determined. To minimize possible variations due to sampling, 1000 replications were performed for each of the 192 possible scenarios; i.e. 1000 JOMLEHD estimates were calculated for each scenario of true population size, number of flights, sighting probability, and capture probability, resulting in 192000 estimates. Simulations Several sets of simulations were run. First, the overall JOMLEHD estimator performance was evaluated given that all assumptions were met. The null hypothesis tested was that neither capture probabilities, sighting probabilities, true population size, nor number of sighting occasions affect the JOMLEHD estimate. For this set of simulations, sighting probabilities were equal and constant for the entire population. Second, sighting probabilities that vary per flight were simulated. null hypothesis tested was that sighting probabilities that change The �150 between flights do not affect the JOMLEHD. Sighting probabilities changed each flight with a value between 0.05 to 0.95 and a mean for all flights of 0.5, and were generated as random numbers from the uniform distribution. Third, a continuous range of heterogeneity in sighting probabilities of individuals was simulated. The null hypothesis tested was that heterogeneity of sighting probabilities of individuals does not affect the JOMLEHD. Four beta distributions and their corresponding parameters were used: [SR) skewed to the right (a - 2, ~ - 4), [SL) skewed to the left (a - 5, ~ - 2), [BE) symmetrically bell-shaped (a - 3, ~ - 3), and [EX) distribution with greater proportions in the extremes (a - 0.5, ~ 0.5). From the specified beta distribution, SAS randomly generated a sighting probability for each animal from the gamma distribution: Yl - rangam (seed, a) Y2 - rangam (seed, ~) sighting probability - Yl / (Yl + Y2)' 2.5 2 , i i "\ "\ i , ...• (II 1'1 41 .." ~ .., 1.5 ...• ...• ...• .t:I all .t:I ~ i ..,~ .... - ..• " I I BE " , ")~ / / M J " "", / , I "'- " " / I II I 0.5 \ "\ .~.~,_._. ' ._o.,_·-_._. __ '_'_'_'_'_'", EX I " I I 0 a "" "\ \ / "\ "\ \ , I , " '.'·t.... 0 0.. j 11"----., / " ,\ I I I " I '. 1 1 , SR ! ! \ .•...~.'" \ \ \ \ "" , \ ,.. / 0.2 O.i 0.6 . 0.8 "\ "-, •••... 1 Sighting proDaDl1lty Figure 1. Beta distribution used in simulations with heterogeneity individual sighting probabilities in �1S Fourth, probabilities of sighting that change exponentially were simulated. The null hypothesis tested was that habituation to the helicopters leading to increased or decreased sighting probabilities with increased number of flights does not affect the JOMLEHD. Maximum sighting probabilities were set at 0.55, 0.70, and 0.90. Minimum sighting probabilities were set at 0.0.10, 0.30, and 0.45. The rates of change were set at lambda values of 0.15, 0.35, and 0.60: sight probability All possible - maximum - ((maximum (1 - e -lambda combinations of the variables * minimum) x flight number were )). simulated. Fifth, a range of aggregations among marked animals were simulated to evaluate the degrees of independence of sighting probabilities. The null hypothesis tested was that nonrandom associations among animals does not affect JOMLEHD. Group size was randomly generated from a uniform distribution ranging from 1 to 24. Sighting probabilities were assumed constant for all group sizes and were given values of 0.1, 0.3, 0.5, and 0.7. Analysis To evaluate the estimator, a mean of the JOMLEHD estimates for each scenario was used. With PROG UNIVARIATE in SAS (SAS Institute Inc. 1985), standard deviations, variances, standard errors, coefficients of variation, and confidence intervals for the mean estimates were computed. To compare the estimates within a given population size, mean squared error (MSE) was calculated using the following equation: MSE - variance + (bias)2. MLEs are assumed to have asymptotically normally distributed estimates; goodness-of-fit tests using the Shapiro-Wilk statistic, W, were used to test the normality assumption by the fit of the simulation results to the normal distribution. Percent relative estimates: bias (PRB) was used to evaluate (estimate - true population the bias of the size) x 100. PRB true population size The Students's t value was used to test the hypothesis that bias equalled zero. The analysis of variance procedure indicated which variables affected the estimate effects: proc anova; class pop flight sight capture; model prb-poplflightlsightlcapture; �)_ l~? where pop - true population size, flight = number of flights, sight = sighting probability, and capture - capture probability (SAS Institute Inc. 1987). The general linear models procedure was used for regression on the variables: proc glm; model prb-poplflightlsightlcapture; Another GLM and a response surface regression was used on all variables and all two-way interactions for lack of fit information, and for analysis of linear, quadratic, crossproduct, and total regression surfaces for optimum response: proc glm; model prb-pop flight sight capture pop*pop flight*flight sight*sight capture*capture pop*flight pop*sight pop*capture flight*sight flight*capture sight*capture; proc rsreg; model prb-pop flight sight capture / lackfit; Tukey's studentized range test was used to detect differences in the mean values by population size. This test was chosen over other range tests because it is the most conservative and assumptions are not violated so robustness is not a consideration. Internal SAS problems prevented an overall Tukey's test but the test could be run by population size: proc glm; class flight sight capture; model prb-flight sight capture flight*flight sight*sight capture*capture flight*sight flight*capture sight*capture; means prb-flight sight capture flight*flight sight*sight capture*capture flight*sight flight*capture sight*capture / tukey; by pop;. The difference between the upper and lower 95% confidence interval values (CIL) was used as a measure of precision. The same programs to evaluate PRB were used here. used Coverage was used as a general indicator of both bias and prec~s~on of the estimate. The percent of the estimates' confidence intervals covering, above, or below the true population size was recorded. For the analysis, above and below categories were reclassified as 'not covers'. Categorical data modeling was used for logistic regression with maximum-likelihood analysis on covers or not: �133 proc catmod; direct pop flight sight capture; model covers-poplflightlsightlcapture ml;. / pred=prob Logistic regression without the direct statement indicated nonlinear effects of variables on the estimate. Insufficient memory prevented overall regression with this method, but with true population size removed, the analysis could be completed: proc catmod; model covers-flight by pop;. This analysis was repeated an I sight I capture / pred-prob ml; for all sets of simulations. RESULTS AND DISCUSSION Basic simulations In general, the precision of the estimate increases and the bias decreases as true population size, number of sighting occasions, capture probability, or sighting probability increase. The percent coefficients of variation of the mean estimate decrease as the four variables increase. Also, the differences between values for upper and lower confidence intervals of the mean estimate decrease, indicating a narrower distribution of estimates around the mean. Within a given population size, the variances of the estimates, the standard errors of the means, and MSE decrease as number of flights, capture probability, or sighting probability increase. At a population size of 50, all sets of estimates are significantly different from the normal distribution (P<O.Ol). At a population size of 100, all but 2 of the 48 scenarios are not normally distributed; at 200, 32 are not normally distributed; and at 500, 18 are not normally distributed. As population size and consequently the sample size increases, more distributions approach the normal distribution and the MLE normality assumption is not violated as often. No other trends in normality are evident as number of flights, sighting probability, or capture probability changed. Percent relative bias (PRB) was used to assess bias. PRB ranges from 60 to 548%. PRB can be negative if the estimate is lower than the true population size. As population size, number of flights, sighting probability, and capture probability increase, the mean PRB estimates, the standard deviations of these estimates, and the differences between the maximum and the minimum values decrease. The coefficients of variation increase as the four variables increase. From the ANOVAs, the sighting and capture probabilities are the main factors affecting the PRB. All variables and all interactions have a highly significant (P<O.OOl) effect on PRB. When GLM for regression was used, all variables and interactions affect the estimate (P<O.Ol, R-square-0.0249 , �154 and F Value-326.64). From the GLM and RSREG with all two-way interactions, the total regression on all variables and two-way interactions fits better than linear, quadratic, crossproduct, or total regression with all variables and all interactions (P<O.Ol, Rsquare-0.025l, and F Value-353.10). All of the variables affect the estimate (P<O.Ol). The lack of fit is high (P<O.OOl) so a high amount of variability aside from the pure error prevents a well-fitted model. The standard errors of the estimates of the regression equation reflect that capture probability and the square of capture probability have the most variability with PRB. Sighting probability, its square, and sighting probability*capture probability also have some variability. With the Tukey's test, 5, 10, and 15 flights have significantly different (P<0.05) PRB with population size 50, and 5 and 10 flights with greater population sizes. The sighting probabilities of 0.1, 0.3, and 0.5 are significantly different with all population sizes except 500, where only 0.1 and 0.3 are different. Capture probabilities 0.1 and 0.3 are significantly different for all population sizes. Thus, minimum variability occurs with 15 flights with population size 50 or with 10 flights with larger population sizes, with sighting probabilities of 0.5 or 0.3 with population size 500, and with capture probabilities of 0.3. The estimated regression equation for PRB is: PRB - 19.40 - (0.02*pop) - (0.80*flight) - (30.ll*sight) (25.89*capture) + (O.Ol*flight*flight) + (13.48*sight*sight) + (10.84*capture*capture) + (O.Ol*pop*sight) + (O.Ol*pop*capture) (0.49*flight*sight) + (0.45*flight*capture) + (18.20*sight*capture) where pop-population size, flight-number of flights, probability, and capture-capture probability. + sight-sighting The confidence interval length (CIL) was used to evaluate precLsLon. CIL values vary from'l to 12001. In general, the variability decreases as the four variables increase. The mean elLs and the coefficients of variation decrease as number of flights, capture probability, or sighting probability increase. The coefficients of variation decrease also as population size increases. The maximum values of PRB decrease. All four variables and all interactions have a highly significant impact on CIL (P<O.OOl). Sighting probability, capture probability, true population size, and number of flights, in that order, have the greatest F values. When GUM for regression was used, all four variables and all interactions except true population size*flight and true population size*flight*capture probability affect the CIL (P<O.Ol, R-square-0.2329, and F Value-3885.ll). From the response surface regression and GLM with all two-way interactions, the total regression on all variables and twoway interactions fits better than linear, quadratic, crossproduct, or total regression with all variables and all interactions (P<O.Ol, Rsquare-0.2460, and F Value-4473.4l). All of the variables affect the estimate (P<O.Ol). The lack of fit is high (P<O.OOl) so a high amount of variability aside from the pure error prevents a well-fitted model. The standard errors of the estimate reflect that capture probability and the square of capture probability have the most variability. Sighting �155 probability, its square, and capture probability*sighting probability also have some variability. With Tukey's studentized tests for differences in the means, 5, 10, and 15 flights significantly differ for population sizes 50 and 100 (P<0.05). With larger population sizes, all of the flights have different CILs. Sighting probabilities of 0.1, 0.3, 0.5, and 0.7 all differ in their CILs at all population sizes. Capture probabilities of 0.1, 0.3, and 0.5 all differ in their CILs at all population sizes. Minimum variability is found with 15 to 20 flights, 0.7 sighting probability, and 0.5 capture probability. The estimated regression equation for CIL is: CIL - 357.69 + (0.49*pop) - (17.l0*flight) - (635.86*sight) (637.3l*capture) + (0.28*flight*flight) + (328.70*sight*sight) + (369.l8*capture*capture) - (0.24*pop*sight) - (0.32*pop*capture) + (10.87*flight*sight) + (11.46*flight*capture) + (472. 25*sight*capture) where pop-population size, flight-number of flights, probability, and capture-capture probability. sight-sighting The coverage was used to assess bias and precision. Percent coverage ranges from 93.6 to 96.7; percent of intervals above the true population size ranges from 1.3 to 3.5; and percent of intervals below the true population size ranges from 1.1 to 3.8. An approximately equal number of the estimates are above (4399 of 192000 - 0.02%) as are below (4538 of 192000 - 0.02%) the true population size. No trends were observed in coverage as true population size, number of flights, sighting probability, or capture probability change. A 95% confidence interval for coverage is calculated as 93.6 to 96.4%. Only four of the scenarios fall above this interval and none fall below. There is no apparent trend with these scenarios. With logistic regression, neither population size, number of flights, sighting probability, capture probability, nor any of their interactions affect coverage (P>O.Ol and likelihood ratio-0.3l88). When the model was tested to include possible nonlinear effects, none of the variables nor their interactions affect cover (P>O.Ol). Apparently, coverage is not predictably variable by using the factors population size, number of flights, sighting probability, and capture probability. Thus population size, number of flights, capture probability, and sighting probability affect the JOMLEHD. Regression equations for PRB and CIL can be used as indicators of bias and precision given these four variables. However, the lack of fit is high and the R-squares are low, especially for PRB. Consequently, the regression equations should only be used as general predictors. Coverage, to reflect both bias and precision, cannot be approximated based on the variables population size, number of flights, sighting probability, and capture probability. �156 Sighting probabilities changing per flight Sighting probabilities are the same for all animals within one flight, but vary per flight between 0.05 and 0.95. The mean sighting probability is 0.5. Similarly to the basic simulations, the variances of the estimates, the standard errors of the mean, the percent coefficients of variation, and the mean squared errors decrease with increasing number of flights or capture probability. However in this scenario, percent coefficient of variation increases with increasing population size. The variability increases faster per population size with changing sighting probabilities than with constant. The decreased variability can be accounted for in the few flights where sighting probability is very high and the precision of the estimates is thus very good. For this same reason, the basic simulations with sighting probability equal to 0.5 are more biased than the simulations with sighting probability changing per flight (P<O.Ol). PRB ranges from -36.5 to 78.0%. The mean PRB estimates and the standard errors of the means decrease as population size, number of flights, or capture probability increase. The coefficients of variation increase as population size or capture probability increases, and remains fairly constant as number of flights changes. Changes per flight do not have as much variability as constant sighting probabilities in maximum and minimum values. The main differences in PRB between basic simulations and changing sighting probabilities falls in small number of flights and small capture probabilities. CIL ranges from 0 to 344 and is significantly lower for changing sighting probabilities than for the basic simulations (P<O.Ol). The mean CIL, the standard errors of the mean, and the coefficients of variation decrease as number of flights or capture probability increase. The coefficient of variation also decreases as population size increases. All of the variables have a significant impact on lowering the CIL for changing sighting probabilities as compared to constant. Coverage ranges from 77.1 to 96.6%; percent of intervals above the true population size ranges from 1.3 to 20.8%; and percent of intervals below the true population size ranges from 1.1 to 3.7%. Percent coverage increases as population size increases and decreases as number of flights or capture probability increase. Percent above changes opposite that of percent covers. Percent below increases with increasing population size or capture probability and decreases with decreasing number of flights. Coverage is especially low for small populations size 50. More confidence intervals are above (2073 of 48000 - 4.3) than are below (1145 of 48000 - 2.4) the true population values. One scenario fell above the 95% confidence interval for percent coverage (population size 500), and 13 fell below. With sighting probabilities changing per flight, those flights with higher sighting probabilities greatly decrease the variance and the bias. The precision is greater and the bias lower here compared to the �1 -~), basic simulations because these simulations as high as 0.95 while the basic simulations Heterogeneity of individual had sighting probabilities had values only up to 0.7. sighting probabilities A continuous range of heterogeneity in individual sighting probabilities was simulated. The beta distribution that was skewed to the right (0 - 2, ~ - 4), SR, had a mean sighting probability of 0.3. The beta distributions that was symmetrically bell-shaped (0 - 3, ~ - 3), BE, and the distribution that was distributed with the greatest proportions in the extremes (0 - 0.5, ~ - 0.5), EX, had mean sighting probabilities of 0.5. The beta distribution that was skewed to the left (0 - 5, ~ - 2), SL, had a mean sighting probability of 0.7. Like the basic simulations, the precision of the estimate generally increases and the bias generally decreases as true population size, number of sighting occasions, capture probability, or mean sighting probability increase. The same trends as the basic simulations occur; percent coefficients of variation and normality increase as four variables increase, and the variances of the estimates, the standard errors of the means, and MSE decrease within a population size with increases in the three variables. With more flights, EX becomes more variable than SR. The variability (percent coefficients of variation, variances of the estimates, the standard errors of the means, and MSE) is greater for heterogeneity of individuals than the basic simulations when comparing the mean sighting probabilities. With 5,10, and 15 flights, a capture probability of 0.1 in the basic simulations has the greatest variability. With 20 flights, the EX distribution from heterogeneity in individual sighting probabilities has the most variability. PRB ranges from -49 to 298%. As with the basic simulations, the mean PRB estimates and the standard errors of the means decrease as population size, number of flights, capture probability, or mean sighting probability increase. The coefficients of variation increase and the differences between the maximum and the minimum values decrease (except for number of flights) as the four variables increase. When compared to the same mean sighting probabilities from the basic simulations, PRB appears lower for constant sighting probabilities than for heterogeneity in sighting probabilities in all scenarios. elL ranges from 0 to 895. The mean elL, the standard errors of the means, the coefficients of variance, the maximum values, and the differences between the extreme values decrease with increasing number of flights, means sighting probability, or capture probability. elL appears slightly lower in basic simulations than for heterogeneity for all scenarios except EX when comparing mean sighting probabilities. Percent coverage ranges from 42.5 to 91.6; percent of intervals above the true population size ranges from 3.4 to 29.8%; and percent of �158 intervals below the true population size ranges from 4.0 to 32.0%. The EX distribution has especially low coverage compared to the other distributions. An approximately equal number of the estimates are above (23397 of 192000 - 12.2%) as are below (24575 of 192000 - 12.8%) the true population sizes. As number of flights increase, percent covers decreases and percent above and below increase. None of the scenarios fell in the 95% confidence interval for coverage; all fell below the 93.6 to 96.4% range. With heterogeneity in individual sighting probabilities, the population estimate is less variable. However, the estimates tend to be lower than the true value and coverage is too low. The resulting estimate would be biased but precise. Populations composed of many animals that are seen frequently or rarely lead to especially biased estimates. A greater number of flights would discern the lack of coverage. Animals becornin~ helicopter shy In this set of simulations, sighting probabilities decrease with increasing number of flights. Sighting probability is a function of a maximum value, a minimum value, and lambda (rate of decrease). Precision increases and bias decreases as population size, number of flights, or capture probability increase. In regard to sighting probability, as the rate of changes increases, the variability and the bias increase; with greater maximums or minimums, the variability and the bias decrease. Mean sighting probability ranges from 0.204 to 0.743. PRB ranges from -44.0 to 450.5%. As with the basic simulations, PRB and its variability decrease with increasing population size, number of flights, or capture probability. The difference of the extremes decreases as number of flights or capture probability increase. elL ranges form 0 to 4049. As number of flights or capture probability increase, the elL and its variability decrease. Likewise, the differences in the extremes decrease as these variables increase. As popUlation size increases, the elL and the variability increase. This variability is reflected in the minimum values of elL at higher popUlation sizes. . Percent coverage ranges from 91.8 to 97.8%; percent of intervals above the true population size ranges from 0.6 to 4.6%; and percent of intervals below the true population size range from 0.4 to 5.0%. Percent below tends to be greater than percent above. Coverage is lower in these simulations than in the basic simulations (29496 of 1295000 2.3% above and 30462 of 1295000 - 2.4% below). Thus with animals becoming less visible with time, the coverage of the estimates decreases. The bias or the elL are not apparently different �159 from those of the basic simulations. The initial sighting probability is important as this is the highest sighting probability. Groups of individuals together all the time -(all group sizes have equal sighting probabilities) In this set of simulations, groups remained together for all flights and sighting probabilities were constant for all group sizes. Similar to the other simulations, the precision increases and the bias decreases as population size, number of flights, capture probability, or sighting probability increase. The same general trends occur in these simulations as the basic simulations. Percent coefficients of variation decrease as the four variables increase; within one population size, the variances of the estimates, the standard errors of the means, and MSE decrease as number of flights, capture probability, or sighting probability increase; and normality increases as population size increases. In general, the basic simulations are more variable than the group simulations. With low sighting probabilities, the estimates with groups of individuals have more variability than the basic simulations without groups; with high sighting probabilities, the basic simulations have more variability than the group simulations. With more flights, only sighting probabilities of 0.1 are more variable in the group simulations than the basic simulations. At higher population sizes, as capture probability increases, the basic simulations become more variable. PRB ranges from -78.0 to 760.0%. As with the basic simulations, the mean PRB estimates and the standard errors of the means decrease as population size, number of flights, capture probability, or sighting probability increase. The coefficients of variation decrease as all but sighting probability increase; sighting probability has no trend in coefficient of variation. The minimum values continue to increase as the four variables increase but the maximum values did not follow a trend. There is no significant difference (P<O.Ol) in PRB between the basic simulations and the group simulations. CIL ranges from 0 to 17236. The mean CIL, and standard errors of the means, and the coefficients of variation of estimates increase as number of flights, capture probability, or sighting probability increase. In general, the maximum value for CIL also decreases as these three increase. CIL is significantly lower for basic simulations than for group simulations (P<O.Ol). The main differences occur in the number of flights, lower capture probabilities, and sighting probabilities. Percent coverage ranges from 22.7 to 96.6%; percent of intervals above the true population size ranges from 1.1 to 76.5%; and percent of intervals below the true population size ranges from 0.6 to 3.9%. Coverage is much poorer at low population sizes with high sighting probabilities. Percent coverage increases with increasing population �160 size. Percent coverage decreases with increasing number of flights and sighting probability. The percent above (13404 of 192000 - 7.0%) changes more than the percent below (4659 of 192000 - 2.4) with changes in percent coverage. As population size increases, percent above decreases; as number of flights, capture probability, or sighting probability increases, the percent above increases. With capture probability, percent above changes inversely with percent below. Percent coverage increases with population size, but decreases with number of flights or sighting probability. Two scenarios fell above the 95% confidence interval for percent coverage (in population sizes 200 and 500) and 47 fell below (all but one in population sizes 50 and 100). Coverage is much poorer with groups of individuals than with the basic simulations. Percent below is similar between the two sets but percent covers is lower with small population sizes, all number of flights, all capture probabilities, and all sighting probabilities (especially higher values). With groups of individuals, the population estimate may appear to be less variable but the coverage is much poorer. With small population sizes, the coverage is low. With low capture probabilities, low sighting probabilities, or with few flights, the population may be overestimated. Thus, violations of the assumptions of mark-resight with mountain sheep lead to estimates that are more variable, more biased, and less precise than would be expected. All of the simulations are being analyzed more rigorously and in more detail to find ways to avoid or limit these problems. Table I. Trends of the simulations where all assumptions are met. as compared Scenario PRB ell x Sighting probabilities changing per flight lower lower Heterogeneity of individuals higher Helicopter shy Groups to basic simulations X above X below lower higher same same lower higher higher same same more variable more variable more variable same higher lower higher lower covers �l6l LITERATURE CITED Bartmann, R.M., G.C. White, L.H. Carpenter, and R.A. Garrott. 1987. Aerial mark-recapture estimates of confined mule deer in pinyonjuniper woodland. J. Wi1d1. Manage. 51(1):41-46. Bear, G., G.C. White, L.H. Carpenter, and R.C. Garrott. 1989. Observabi1ity bias in mark-resighting estimates of elk populations. J. Wild1. Manage. (in press) Bergerud, A.T. and F. Manuel. 1969. Aerial census of moose in central Newfoundland. J. Wi1d1. Manage. 33(4):910-916. Carothers, A.D. 1973. Capture-recapture methods applied to a population with known parameters. J. Anim. Ecol. 42(1):125-146. Caughley, G. 1974. Bias in aerial survey. J. Wildl. Manage. 933. Caughley, G. 1978. Analysis of vertebrate Sons. New York, New York. 234pp. populations. 38(4):921- John Wiley and Chapman, D.G. 1951. Some properties of the hypergeometric distribution with applications to zoological sample censuses. Dniv. Calif. Publ. Stat. 1(7):131-160. Darroch, J.N. 1958. The multiple-recapture census. I. Estimation closed population. Biometrika 45(3/4):343-359. of a DeYoung, C.A. 1986. Accuracy of helicopter Texas. Wild1. Soc. Bull. 13:146-149. surveys of deer in south Eberhardt, L.L. 1969. Population estimates J. Wildl. Manage. 33:28-39. from recapture frequencies. Eberhardt, L.L., D.C. Chapman, and J.R. Gilbert. 1979. A review of marine mammal census methods. Wi1dl. Monogr. 63:1-46. Floyd, T.J., L.D. Mech, and M.E. Nelson. 1979. An improved method of censusing deer in deciduous-coniferous forests. J. Wi1d1. Manage. 43(1):258-261. Furlow, R.C., M. Hader1ie, and R. Van den Berge. 1981. Estimating bighorn sheep population by mark-recapture. Desert Bighorn Council, Trans. 1981:31-33. a Kufe1d, R.C., D.C. Bbwden, and D. L. Schrupp. 1987. Estimating mule deer density by combining mark-recapture and telemetry data. J. Mamm. 68(4):818-825. LeResche, R.E. and R.A. Rausch. 1974. Accuracy and prec~s~on of aerial moose censusing. J. Wildl. Manage. 38:175-182. Leslie, D.M., Jr. and C.L. Douglas. 1979. Desert bighorn sheep of the River Mountains, Nevada. Wildl. Monogr. 66:1-56. �l62 Leslie, D.M., Jr. and C.L. Douglas. 1986. Modeling bighorn sheep: current abilities and missing Wildl. Natur. Res. Conf. Transc. 51:62-73. demographics of links. N. Amer. Lincoln, F.C. 1930. Calculating waterfowl abundances on the basis of banding returns. U.S. Dept. Agric. Circ. 118. 4pp. Magnusson, W.E., Caughley, G.J., and G.C. Grigg. 1978. A double-survey estimate of population size from incomplete counts. J. Wildl. Manage. 42(1):174-176. McQuivey, R.P. 1978. The desert bighorn Game BioI. Bull. No.6 8lpp. sheep of Nevada. Nevada Fish, Otis, D.L., K.P. Burnham, G.C. White, and D.R. Anderson. 1978. Statistical inference from capture data on closed animal populations. Wildl. Monogr. 62:1-135. Packard, J.M., R.C. Summers, and L.B. Barnes. 1985. Variation of visibility bias during aerial surveys of manatees. J.Wildl. Manage. 49(2):347-351. Petersen, C.G.J. 1896. The yearly immigration of young plaice Limfjord from the German sea. Rept. Danish BioI. Stn. into Pollock, K.H. and W.L. Kendall. 1987. Visibility bias in aerial surveys: a review of estimation procedures. J. Wildl. Manage. 51(2):502510. Quinn, T.J. II. 1980. Sampling for the abundance of schooling population with line-transect, mark-recapture, and catch-effort methods. Ph.D. dissertation. University of Washington. Rice, W.R. and J.D. Harder. 1977. Application of multiple sampling to a mark-recapture census of white-tailed Wildl. Manage. 41(2):197-206. aerial deer. J. Samuel, M.D., E.O. Garton, M.W. Schlegel, and R.G. Carson. 1987. Visibility bias during aerial surveys of elk in northcentral Idaho. J. Wildl. Manage. 51(3):622-630. SAS Institute version Inc. 1985. SAS procedures guide for personal computers, 6 edition. Cary, NC: SAS Institute Inc. 373pp. SAS Institute Inc. 1987. SAS/STAT guide for person computers, edition. Cary, NC: SAS Institute Inc. 1029pp. version Schnabel, Z.E. 1938. The estimation of the total fish population lake. Amer. Math. Mon. 45(6):348-352. of a 6 �163 Seber, G.A.F. 1982. The estimation of animal abundance and related parameters (2nd edition). Macmillan Publ. Co., Inc. New York, New York. 654pp. Seber, G.A.F. 1986. A review for estimating animal abundance. Biometrics 42:267-292. Strandgaard, H. 1967. Reliability of the Petersen method tested on a roe-deer population. J. Wildl. Manage. 31:643-651. White, G.G., D.R. Anderson, K.P. Burnham, and D.L. Otis. 1982. Gapturerecapture and removal methods for sampling closed populations. Los Alamos National Laboratory. LA-8787-NREP. Los Alamos, N.M. White, G.G. and R.A. Garrott. primer. (in press) 1989. Analysis Prepared by Andrea K. Neal Graduate Research Assistant of biotelemetry data - a ��165 JOB PROGRESS State of Colorado Project No. 01-03-048 Work Plan No. 3 Job No. 2A Period Covered: Author: REPORT Mammals CW-153-R-2) 2 Research Pronghorn Investigations Habitat Selection and population Performance of a Pioneering Pronghorn Population July 1, 1988 - June 30, 1989 T. M. Pojar ABSTRACT Seven radioed pronghorn (Antilocapra americana) remain of the original 9 that were radioed in Dec 1986. Another trapping operation was conducted in Dec 1988, during which 67 pronghorns were captured. Twenty new radios were deployed (15 on adult females and 5 on adult males). Data are analyzed on the original 7 radioed animals for the period Dec 1986 through Sep 1988. Seasonal and yearlong areas of habitation were calculated. The wintering area of the pronghorn population did not overlap any of the critical winter range for mule deer (Odocoileus hemionus) in Middle Park. During the 2 years the pronghorn population has been monitored, it has increased at an annualized rate of 41.4%. ��- 1 .- HABITAT _ SELECTION AND POPULATION PERFORMANCE PRONGHORN POPULATION OF A PIONEERING Thomas M. Pojar P .N. OBJECTIVE Describe population dynamics pronghorn population. and habitat use of a pioneering, expanding SEGMENT OBJECTIVES 1. Describe seasonal population. and annual distribution of the Middle 2 Determine necessary 3. Monitor population dynamics of Middle Park pronghorns with: a. Ground counts to describe changes in population size. b. Ground counts to quantify population sex and age composition. sample sizes of radio-collared animals to describe habitat preferences. Park pronghorn and observations ACKJmWLEDGMENTS The trapping operation was facilitated through the efforts of Steve Steinert, Joe Gerrans and Area 9 personnel: J. Liewer, J. Claassen, R. Firth, A. Chappell, B. Thompson, B. Sigler, M. Middleton, J. Hicks, and J. Frank. Personnel from the Kremmling Bureau of Land Management district provided assistance during trapping as did several local Kremmling residents. K. Cushman and S. Fairbanks served as recorders and M. Atkins managed marking supplies during the trapping operation. M. Miller assisted in blood sample collection and processing for both hematological diagnostic panel and leptospirosis testing. The CDOW NW Region contributed helicopter time for the trapping operation. D. Schrupp, A. Cade, and J. Miller were instrumental in the data processing and mapping of seasonal areas of habitation. STUDY AREA The study area is described in Pojar (1988:183-184). METHODS AND MATERIALS The trap used was a corral trap with peripheral curtains and an interior diagonal curtain (same as in 1986). Trapping and handling procedures followed those sanctioned by the Pronghorn antelope Workshop (Anonymous 1984). ') . �163 Radio tracking was done mostly from the ground to increase the probability of observing and~dentifying animals with numbered plastic collars. Fixed wing aircraft was used if an animal could not be located after reasonable effort from the ground. Legal descriptions of animal locations were recorded to the nearest quarter mile then converted to UTM (U.S. Army 1973) coordinates for computer processing. All areas of habitation are based on m~n~mum convex polygons as calculated by the program McPAAL (Stuwe ND). The map plots of pronghorn habitat, areas of habitati ~, mule deer critical winter range, and individual point locations were accomplished through the SAGIS (Bartholow 1981) software package. The base map used was: C.S. Department of Agriculture Forest Service R~lltt National Forest, Colorado, Sixth Principal Meridian, 1975 (reprint 198 The original scale of 1:126720 was reduced to 1:230400 via photographic tec~niques at the Colorado State University Photo Lab. RESULTS Trapping and Marking On 15 Dec 1988, 67 pronghorns were captured in 2 catches at a trap site east of Kremmling on BLM land (T1N,R80W,NE 1/4 S 11). There were no pronghorn fatalities or injuries as a result of the trapping operation. Twenty new radio transmitters (Advanced Telemetry Systems) were deployed, 15 on adult females and 5 on adult males. Tables 1 through 4 detail the current status of marked pronghorns in Middle Park. In summary, there are 24 functional radio transmitters (4 remaining from the 1986 trapping) (Table 1), 29 animals with blue plastic collars and either a blue or yellow ear tag (Table 2), and 14 animals with a blue ear tag only (fawns were not collared because of potential growth) (Table 3). Of the 47 animals trapped in 1986, 13 were recaptured in the 15 Dec 1988 trapping operation (Table 4). Population Size and Structure The winter population in 1986-87, the first year of this study, was 80 animals. The herd structure at that time, based on the sample of 47 trapped animals, was 36B:100D:77F. The following year, 1987-88, the winter population increased by 55% to 122 with a structure of 44B:100D:70F. This represents production of 95 fawns per 100 producing-aged does. Lower production, 61F:100 mothers, in 1988 resulted in a lower population growth rate of 31% and a winter 1988-89 population of 160. An estimate of the herd structure based on a sample of 108 animals on 26 Oct 1988 was 40B:100D:32F and the sample of 67 animals trapped 15 Dec 1988 was 40B:100D:40F. From these estimates and the total count of 160 animals in the 1988-89 winter population, it was projected that the population should contain 37 yearling and mature bucks. On several occasions during winter, it was possible to get an accurate count of bucks. These counts were consistent at 35-36 bucks. This offers support that it may be possible to obtain accurate herd structure ta if surveys are done shortly after the breeding season when the breeding se~~on social structure has broken down. �Tests for Leptospirosis A random sample of the blood samples (n-10) collected during the 15 Dec 1988 trapping operation was tested for titers against 5 strains of the leptospirosis bacteria (Leptospira sp.). The sample was limited only to females age 3+ because they would be the most likely to have been exposed to the disease if it were present in the population. They were all negative (Table 5). The tests were done at the Diagnostic Laboratories, Colorado State University. Areas of Habitation Uith few exceptions, all radioed animals have been located every 2 weeks. Animal with radio frequency 149.370 was killed in a collision with an automobile on 14 July 1987 resulting in a minimal data base for her. Radio frequency 149.290 ceased to function curing April 1988. The bulk of the location analysis contained in this report, therefore, has been done on the remaining 7 radioed animals, all of which are mature does. The legal descriptions of radioed pronghorn locations were converted to UTM coordinates. Thus far, location data have been analyzed for the time period of Dec 1986 through Sep 1988. These data are reflected in Figures 1· - and Table 6. True seasons based on equinox and solstice did not fit the seasonal movement patterns of the pronghorns. The location data were arbitrarily assigned to seasons as follows: winter-Dec, Jan, and Feb; spring-Mar, Apr, and May; summer-Jun, Jul, and Aug; and autumn-Sep, Oct, and Nov. A finer delineation of seasons and transition periods will be possible as the data base of locations expands. Uinter Area of Habitation The winter area of use by the Middle Park pronghorn population is of particular interest of managers because of the potential overlap with mule deer use areas. The areas of "critical winter range" for mule deer, as defined by Tiedeman et al. (1987), are included in the digitized map for the pronghorns' winter area of habitation (Figure 1). The critical areas for mule deer are south-facing slopes and the area of use by pronghorn is mostly windblown ridgetops. For the winter of 1987-88, which was moderate to light in terms of severity, there was no overlap between the 2 species. Pronghorns are quite sedentary in winter (Figure 5). The average area of habitation for 7 radioed animals was 18 km2 (7 mi~ with a coefficient of variation of 14.22% which is much lower that for any other season (Table 6). The area described for the radioed animals will almost exactly describe the area for the entire population because they are usually in one large group during this time of year. Spring Area of Habitation Spring is a time of much movement and large variation among individuals (Figure 5). Spring areas ranged from 22 km2 (8.5 mi~ for one animal to 83 km2 (32 mi~ for another with the average for all animals of 51 km2 (48 mi~ (Table �1:-0 6). The dispersion of the radioed animals (Figure 2) does not accurately depict the tf'"uedispersion of the population. Reliable reports have been received of marked individuals (plastic neck collar and/or ear tag) in the Grandby/Hot Sulphur Springs and Muddy Pass areas and one ear-tagged animal was seen in North Park (See Pojar 1988 for details) during spring and summer of 1988. In 1989, sightings of several pronghorns were reported (J. Claassen, pers comm) in the Coffee Divide area approximately 3 miles North of Grandby. This group included one animal with a blue plastic collar. These sightings verify that a certain segment of the Middle Park population summer in the far eastern and northern reaches of the park but return to an area immediately north and east of Kremmling to winter (Figure 1). The new set of radios deployed in Dec 1988 include several animals that summer in the Northern part of the park (Muddy Pass area) but unfortunately, no radioed animals are included in the group that summers in eastern area of the park (Grandby area). Summer Area of Habitation During fawning and for several weeks thereafter females remain on relatively small fawning areas. The average area of habitation for this arbitrary definition of season is 24 krn2 (9 mi~ (Table 6). This season includes the time interval during which there are erratic movements of some does just prior to fawning and movements of does with fawns to join larger doe/fawn groups during the latter part of this period. The area of use by does during the fawning period is much smaller than for this entire season and will be much better described as more data points become available. The disbursement of animals is maximized during this season but some of them remain on portions of the wintering area yearlong (Figure 3). Once again, other sightings of ear-tagged or plastic collared animals verify that the summer dispersion of the entire population is greater than Figure 3 indicates. Autumn Area of Habitation This season encompasses the breeding season and the early stages of large wintering group formation. Location of the 7 radioed animals in Oct/Nov and their companions results in observing two-thirds or more of the entire population. Consequently, the distribution depicted in Figure 4 probably closely resembles the distribution of the whole population. Yearlong Area of Habitation A composite of all location points for 7 radioed animals was used to calculate the "yearlong" areas presented in Table 6. The average yearlong area of habitation was 79 krn2 (31 mi~ and was moderately variable between individual animals (c.v.-42.8l%) (Figure 6). �SUMMARY This population has had an annualized rate of increase of 41.4% during the 2 years thus far monitored. If this rate is maintained, the population will exceed 300 animals by the autumn of 1990. Management plans are to begin hunting when the population reaches 300 animals. Although the data base for radioed animals is minimal at this point, there are some trends of interest emerging. Wintering areas of pronghorns and mule deer did not overlap although they were in close proximity. This is in agreement with findings of a study in eastern Montana (Wood 1989) where these species had some habitat use overlap but maintained a high degree of spacial segregation. LITERATURE Anonymous, 1984. Proceedings CITED Management guidelines: Trapping and Translocation. of the Pronghorn Antelope Workshop 11:237-251. Bartholow, J. 1981. SAGIS-WINDOW documentation. U.S. Fish and Wildl. Serv., Western Energy and Land Use Team. BioI. Servo Program, Ft. Collins, CO. 40pp. Pojar, T.M. 1988. Habitat pioneering pronghorn 181-192. selection and population performance of a population. Colo. Div. Wildl. Res. Rep. July, pp Stuwe, M. ND. McPAAL micro-computer programs for the analysis of animal locations. Program Documentation. Cons. and Res. Center, Natl. Zool. Park, Smithsonian Inst., Front Royal, Virginia. Printout. 18 pp. Tiedeman, J.A., R.E. Francis, C. Terwilliger, Jr., and L.H. Carpenter. Shrub-steppe habitat types of Middle Park, Colorado. USDA Forest Service, Res. Paper RM-273, 20 pp. 1987. U. S. Army. 1973. Technical Manual: Universal transverse mercator grid. Headquarters, Dep. of the Army, Washington D.C. TM No. 5-241-8, 64 pp. Wood, A.K. 1989. mule deer. Prepared Comparative distribution J. M.amm. 70(2):335-340. ( Ul---v;_ A ili bY~7~ Wildlife Researcher C and habitat use by antelope and �1 ..l./":" " Table 1. Record of radio transmitters deployed as of 15 Dec 1988. includes 4 radio? that were deployed 16 Dec 1986. Species: Pronghorn Trap Site Location: Capture Freq. 148.390 148.400 148.410 148.430 148.440 148.450 148.460 148.520 148.530 148.540 148.550 148.560 148.570 148.580 148.590 148.600 148.620 148.630 148.640 148.650 148.700 148.750 148.850 148.950 Date: americana) BLM land, T1N,R80W,NE 1/4 S 11 15 Dec 1988 Nearest Town: Kremmling Wing trap wi curtains Method: Define seasonal and annual home range Sex Age Ear Tag F F F F F F F M F F F F F F M M F F F M F M F F 3+ 3+ 3+ 3+ 3+ 3+ 3+ Yr1 3+ Yr1 Purpose: Radio (Anti1ocapra The list Y 2 Y 4 B 25 Y 9 Y 7 Y 12 B 26 B 2 Y 1 B 6 2 B 8 2 Yr1 Yr1 3+ 3+ 3+ Yr1 3+ Yr1 Yrl 3+ 3+ Yrl B 27 B 5 Bll B 3 Y 3 B B B B B 14 23 24 16 17 Y 19 Y 10 B 10 Comments Radio put on 16 Dec 1986. Radio put on 16 Dec 1986. New radio. Radio put on 16 Dec 1986. Radio put on 16 Dec 1986. Replaces radio 149.250. New radio. New radio. Magnet left on. Replaces radio 148.420. New. New. New. New. New. New. Ear tgd as a fawn 12/16/86. New. New. New. New. New. Replaces Yellow # 8 collar. Replaces radio 149.210. New. �2. Table Species: Record of neck collars Pronghorn Trap Site Location: Capture (Antilocapra put on 15 Dec 1988. americana) BLM land. T1N.R80W,NE Define seasonal Ear tag Sex B 1 B 2 B 19 M M Y Y 27 B 21 Y 22 M M Y B 5 B 40 M 2 B 6 Y 28 M 3+ B 7 B 47 Y B 8 B 9 B 51 Y 32 B 28 3+ B 30 B 50 Y 42 Y 41 Y 17 M M M F F F F F F F F F F F F F F F F F F F F F Y 18 Y 21 F Bll 12 B 29 Bl3 B 14 B 15 B 16 B 30 B B 17 B 18 B 19 B 20 B21 B 22 B 23 B 24 B 25 B 26 B 27 B 28 B 29 Note: S 11 Nearest Town: Kremmling and annual home range Neck collar B 4 1/4 15 Dec 1988 Wing trap wi curtains Method: Purpose: B 3 Date: B 31 B 32 Y 39 B 34 B B B B B 36 37 38 41 39 B 42 B 43 B 45 B 44 B 46 B 49 An animal aged as "adult" Age 3+ 3+ 3+ 3+ Y Y 3+ 3+ 2 3+ 2 3+ 2 3+ 2 3+ Y Y Y 2 3+ Y 3+ 3+ 3+ Comments New Ear tagged as fawn Dec '86. New Replaces Yellow neck #10, "Adult" in Dec '86. New Ear tagged as fawn Dec '88. New New "Adult" in Dec '86. New New New New New Ear tagged as fawn Dec '86. New New New New New New New New New New New New New Ear tagged as fawn Dec '86. "Adult" in Dec '86. Collar not replaced. Replaces yellow neck # 9, Yearling in Dec '86. in 1986 was a yearling or older. �1 -, J.. /-+ Table 3. Record of blue ear tags put on 15 Dec 1988. Species: Pronghorn (Antilocapra Trap Site Location: Capture Bo land, T1N.R80W,NE 1/4 Date: S 11 15 Dec 1988 Nearest Town: Kremmling Wing trap wi curtains Method: Define seasonal Purpose: Note: americana) This list contains and annual home range only fawns of the year (one exception). Neck collars were not put on any fawns. Ear Tag B 1 B 4 B 7 B 9 B 12 B 13 B 15 B 18 B 20 B 22 B 33 B 35 B 48 B 52 BB yy Sex F M F M M M F M F M M M M M F F Comments New New New This is a yearling, did not get collar. New New New New New New New New New New Blue tag in each ear. Marked summer '88. Yellow tag in each ear. Marked summer '88. �Table 4. Species: S~~~us of animals marked 16 Dec 1986. Trap Site Location: Neck/Radio Collar Ear Tag 148.390 148.400 148.420 148.430 148.440 149.210 149.250 149.290 149.370 Y 1 Y 2 Y 3 Y 4 Y 5 Y 6 Y 7 Y 8 Y 9 Y 10 Yll Y 12 Y13 Y 14 Y 15 Y 16 Y 17 None None None None None None None None None None None None None None None None None None None None None Date Trapped: Pronghorn Jody Hill's, T2N,R80W, SW 1/4 S 36 Sex Age F F F F F F F F F M F M F F F F F F F 2+ 2+ 2+ 2+ 2+ 2+ 2+ 2+ Yr1 2+ Yr1 2+ 2+ 2+ 2+ Yr1 2+ Yr1 2+ 2+ 2+ Yr1 2+ Yr1 2+ 2+ Y 3 M F Yll Y 23 Y 27 Y 28 Y 29 Y 30 Y 31 Y 32 Y 34 Y 35 Y 36 Y 38 Y 39 Y 42 Y 43 Y 44 Y 45 Y 46 Y 47 Y 48 F F F(M) F(M) M F M 2+ M 2+ F M F Y 2 Y 4 Y 1 Y 9 Y 7 Y 10 Y 12 Y 20 Y13 Y 5 Y 8 Y 6 Y 14 Y 15 Y 17 Y 18 Y 19 Y 21 Y 22 Y 16 Y 24 Y 25 Y 26 Y 33 Y 40 Y 41 16 Dec 1986 M M F F F F M M M F F M F M F F F F F F 2+ F F Yrl F F F F F F F F F F Date Last Observed 12/29/88 12/29/88 12/29/88 12/29/88 12/29/88 12/29/88 12/29/88 8/11/88 7/14/87 10/12/88 9/30/87 3/17/88 11/22/88 4/7/88 11/22/88 10/2/88 12/29/88 12/15/88 12/15/88 11/22/88 12/6/88 11/22/88 4/21/88 12/6/88 12/6/88 12/15/88 12/29/88 not seen summ '88 12/15/88 12/15/88 9/27/88 10/12/88 not seen 12/15/88 not seen not seen not seen not seen 12/15/88 12/15/88 not seen not seen 6/13/88 10/20/87 not seen not seen Comments Raised 2 fernfawns '88 New radio #148.530. New radio #148.850. New radio #148.450. Radio quit 4/7/88. Killed by auto. New radio #148.750. New yellow neck #18. New blue neck #4. Trapped and released. New radio #148.600. In N. Park, Steinert Blue neck #2. A male!! Blue neck #6. A male!! New blue neck #9. New blue neck #16. New blue neck #30. �176 Table 5. Results of tests for titers against 5 strains of the leptospirosis bacteria (LeI;!tosI;!'ira sp. ) from Middle Park pronghorns trapped 16 December 1988. Animal 1.D. I Sex B14 B24 B25 B26 B46 Yl Y10 Y12 Y2l Y42 F F F F F F F F F F Age 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ Hardjo Ictero Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Strain of Le2tos~ira Ganico Grippo Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Pomona Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. Neg. 1 Ear tag, B-blue and Y-yellow. Table 6. Seasonal areas (km~ of habitation for 9 radio collared pronghorns in Middle Park for December 1986 through September 1988. Winter-DJF, spring-MAM, summer-JJA, autumn-SON. Season Animal Winter Spring Summer Autumn Total Yearlong 148.39 148.40 148.42 148.43 148.44 149.21 149.25 149.29 149.37 16.29 19.10 12.80 18.64 19.14 14.61 18.64 20.40 9.66 67.76 41.50 31.42 24.32 32.73 56.28 83.24 76.64 21.65 16.45 12.41 38.86 38.86 14.25 26.96 11.30 37.86 n.d.3 18.44 24.02 l.38 3.08 13.79 n.d. 3 31.74 50.98 n.d. 3 118.94 97.03 84.47 84.91 79.91 97.84 144.91 185.89 31.31 80.29 54.22 32.17 8l.28 6l.41 88.55 129.04 113.84 27.66 Ave.4 S.D. 5 G.V. 6 17.86 2.54 14.22% 51.09 24.14 47.25% 24.28 13.42 55.27% 20.49 17.25 84.19% 113.72 39.40 34.65% 78.89 33.77 42.81% 1 Total of all seasons, there is some overlap between seasons which results in this total being larger than the yearlong area. 2 This area represents the minimum convex polygon of all points on a yearlong basis. 3 n.d.- no da ta . 4 The average does not include data for 149.21 and 149.37. 5 Standard deviations calculations do not include data for 149.21 and 149.37. 6 G .V .- coeffic ient of variation. �- ., " . \ ;~;-,-- -~~._:'.- -'-,.!'. Figure 1. Winter area of habitation of 7 radioed pronghorns during the period Dec 1986-Sep 1988. Triangles represent pronghorn locations for Dec, Jan, and Feb; and outlined areas are critical winter range for mule deer as defined by Tiedeman et a1. (1987). �p.ro 0 Ii ~ '-< III ~() ..." ::s III Ii H') 0 Ii ::s 0 p. (I) P. ..." 0 III ::s ::s c III Ii ~ro H')()Q 0 Ii rt ::r' ::s ti•...' (/l ::s 0 ..." P. rt ~O 0 ti 0 III (/l ::s~ ::r'ti 0 0 ti ::s ()Q"d "d Ii 0 rt ::s ro --..J (/l ro Ii "d Ii ro Ii (/l ro III OQ rr ~..." ::s ..." ..." III rr ::r' 01 III Ii 0- \Dill 00 000 H') ~(I) "d ro VlOQ I 0\ ~Vl \D"d 00 Ii ro P.ON ::s III . ,..., I-rj »"d "d ro ..." Ii liOQ ~.loI.UVl •• I -I 'J'\ I ~ ...",. ~. ,... : """""'-1 ~·':':"I Ii:'.' I (lOOt ....K~•.• :. "'I\llI''' ...•.• " .1 '! ~: II 1 •• .\ II U .. 1.,.."'IJ. /' N'":. " I':.~ u. .j ., •" .~. ,r I ..I I -- , ... l' .....-_.~I.:.;:,;-~., r'! i ., I I .~c.• o: - I t-' �L -,~ Figure 3. Summer area of habitation for 7 radioed pronghorns during the period Dec 1986-Sep 1988. Triangles represent pronghorn locations for Jun, Jul, and Aug. �180 Figure 4. Autumn area of habitation Triangles period Dec 1986-Sep 1988. Oct, and Nov. for 7 radioed pronghorns during the represent pronghorn locations for Sep, �250 i. ql WINTER SUMMER k <I AUTUMN 200 150 100 50 o 1.••. 31 1.•8..•.• 1"8.42 1.• 8 ..• 0 148.43 141.21 141.25 AVE. ANIMAL 1.0. Figure 5. Middle Park pronghorns seasonal area of habitation for Dec 1986Sep 1988. Winter-DJF, spring-MAM, summer-JJA, and autumn-SON. One square mile - 2.59 square kilometers. �140 120 100 s ~ 0 en 80 Z « w a: « ...J « I- 10 0 I- 40 20 o 148.3' 148.42 148.40 148.44 148.43 141.2' 141.25 AVERAGE ANIMAL 1.0. Figure 6. Yearlong during Dec 1986-Sep area of habitation 1988. of 7 radioed pronghorns in Middle Park �183 Colorado Division Wildlife Research July 1989 of Wildlife Report JOB FINAL REPORT State of __~C~o~l~o~r~a~d~o __ Project No. 01-03-048 (W-1S3-R-2) Mammals 2 Research Work Plan No. 3A Pronghorn Job No. 1 Pronghorn recruitment and survival in Escarpment data analysis unit. Period covered: Author: Investigations July 1, 1988 - June 30, 1989 T.M. Pojar ABSTRACT This was an exploratory project to make a preliminary assessment of this pronghorn (Antilocapra americana) population's reproduction. A ground survey by vehicle was made to estimate the herd structure. The survey was completed during 29-30 August, 1988 using 6, 2-person crews. A total of 2,374 miles of route were driven and 70S pronghorns were classified yielding bucks:100does:fawns ratios of 61:100:66. The 90% confidence intervals were B:100D ± 34% and F:100D ± 17%. From this meager information it was concluded that an extensive fawn mortality study is not merrited at this time. It is suggested that general popUlation mortality factors and/or movements of segments of the population would provide a more fertile area of investigation. To accomplish this, more reliable estimates of population parameters must be collected by using more precise census methods. Radio telemetry methodology should be used to determine animal movements annually and by season. ��185 PRONGHORN RECRUITMENT AND SURVIVAL IN ESCARPMENT DATA ANALYSIS UNIT Thomas M. Pojar INTRODUCTION This project was initiated as a preliminary assessment of the reproductive performance of the Escarpment DAU (data analysis unit) pronghorn population. This is a large (4300 square miles) and diverse area (Figure 1) with land use practices that include irrigated agriculture in the southern part of the area, dryland wheat farming in the central and east, and domestic livestock grazing of native shortgrass prairie in the north and west portions of the area. ACKNOWLEDGEMENTS The following persons participated in the herd structure survey: M. Ball (U.S. Forest Service), and the following from the Colorado Division of Wildlife, C. Crawford, D. Crawford, L. Crooks, T. Davis, J. Dennis, K. Dillinger, A. Duvall, J. Rogstad, L. Ragstad, G. Schoonveld, S. Steinert, B. Smith, and J. Wagner. METHODS AND MATERIALS The initial effort was to get an estimate of the herd structure and get an indication of how it may vary across the entire area. To accomplish this, the area was stratified into high, medium, and low pronghorn density based on the best judgement of management personnel. These strata were then each arbitrarily subdivided into 3 "blocks" each, that were roughly equal in size, to ensure distribution of the sample units (see Figure 1). Given the amount of time and number of personnel available, it was determined that it would be possible to examine a 10% sample of the total area. To ensure the most efficient use of time the total sample was allocated to each stratum based on the optim~ allocation formula in Cochran (1963:97, Sampling Techniques, John Wiley & Sons Inc. New York 413 pp). The weights assigned were: High density, 3; medium density, 2; and low density, 1. The sample unit was a square mile and the mode of search was from a vehicle using binoculars and a 20+ power spotting scope. Each crew consisted of a driver and a spotter and the method of search was to drive from sample unit to sample unit by the shortest route and classify all pronghorns seen both enroute and on each sample unit. The number of miles traveled by each crew was recorded to get a general index of relative pronghorn density between strata. �186 RESULTS Stratification and optimum allocation of the total sample resulted following distribution of the sampling effort. Strata Total Area No. Samples % Sampled High Medium Low 1710 1109 1488 252 116 81 14.7 10.4 5.4 Totals 4307 449 10.4 Relative density as follows. Strata as derived Miles from number Driven of pronghorns No. Pronghorns in the seen per mile driven is Pronghorns/Mile High Medium Low 1135 556 683 515 109 81 .45/mile .19/mile .l1/mile Totals 2374 705 .30/mile The classification survey was completed during 29-30 August 1988 with the results for the entire Escarpment DAU being 61B:100D ± 34% and 66F:100D ± 17% (Table 1). The confidence limits are calculated at the 90% level. The results by strata are included in Table 1. The ratios for medium and low density are unreliable because of the small sample. prepared~1t !2(iw omas M. POJa Wildlife Researcher �187 Table 1. Herd structure for Escarpment pronghorn data analysis unit obtained from vehicle ground routes during Aug 29-30, 1988. Areal Sample Size Bucks: 100Does 90% C.L.2 Fawns: 100Does 90% C.L.2 Low 81 60 87% 60 37% Medium 109 35 100% 34 83% High 515 69 49% 76 13% Total 705 61 34% 66 17% 1 The total area of 4,247 square miles was partitioned into low density (1488 mi2) , medium density (1109 mi2), and high density(16s0 mi2). 2 The 90% confidence limits are in terms of plus or minus the given percentage. �I--' co oo E S()-O>1p/t"S / 13 f-\ K ",t. 1I"'t'~) Figure 1. Escarpment pronghorn DAU stratified and blocked for purposes of herd structure sampling. numbers in parentheses are the total nwnber of sample units (square miles) drawn at random the total number of potential sample units in the area (no. sample units/total no. units). The over �189 Colorado Division Wildlife Research July 1989 of Wildlife Report JOB PROGRESS REPORT State of Project Colorado No. ~Y_-~1~5~3~-R~-3~ York Plan No. Job. No. 1 Period Covered: Author: Personnel: ~6~A~ _ Mammals _ Mountain Lion Investigations Mountain Dynamics Lion Population Research July 1, 1988 - June 30, 1989 A. E. Anderson See acknowledgments ABSTRACT The results of preliminary data analyses are briefly described. A final, comprehensive, peer-reviewed report should be completed by November, 1990. ��191 MOUNTAIN LION POPULATION DYNAMICS Allen E. Anderson P. N. OBJECTIVE To assess the effects of sport hunting on mountain lion populations. SEGMENT OBJECTIVE To prepare final reports for publication. ACKNOWLEDGMENTS All statistical analyses were performed by Dr. D. C. Bowden, Statistics, Colorado State University, Fort Collins. METHODS Department of AND MATERIALS General methodology was described in Anderson (1983a). Aerial telemetry and all other field work were terminated on July 14, 1989. Checking and assembling data, planning data analyses and preliminary examination of home range dynamics and survival rates of radio-collared puma occupied much of the segment. D. Bowden conducted simulation studies to validate expressions relative to the direct application of nonparametric tolerance (NPT) region results and the attachment of a utilization statement (U). U is defined as the proportion of an animal's time during the time period of interest that the animal spends within the minimum convex polygon area. I investigated the feasibility of using the methodology of Marcum Loftsgaarden (1980) to quantify habitat preferences of puma. and RESULTS AND DISCUSSION Segregation of Data The radio-collared puma were segregated into 2 groups for analysis. First, based on both the scanty literature and our grossly approximate age assignments (Anderson 1983b), I set 24 months as the probable minimum age of sexual maturity in wild puma. Also, because spatial dynamics over the annual cycle were of interest, I included only those presumably sexually active puma whose length of telemetric surveillance was ~ 12 months. The resultant number of aerial locations from those "resident" puma available for analysis by year and period for 7 males (Table 1) and 10 females (Table 2) totaled 2,317. Second, I combined both resident and nonresident puma (Table 3) whose aerial �192 locations and other observations suggested: (a) interactions between motheryoung and litter-mates and (b) dispersion in young puma of each sex. Some hypotheses which could be tested include the following: (1) The generally larger home range area of male resident puma begins during the postnatal period. (2) The core area of dependent males is at a greater distance from the core area of the mother than that of dependent females. (3) Dispersing subadult males travel at greater rates than dispersing subadult females. Dynamics of Home Range Size and Survival Rates Preliminary analyses of the dynamics of home range size of resident male and female puma is given in Appendix 1. Survival rates estimated for male and female puma from about 2 to 84 months of age are in Appendix 2. Simulation Results The simulation results indicated that the expressions were valid for the direct application of NPT and to provide a lower bound for U. In fact, the expressions were also applicable to similar applications for mule deer (Bowden and Kufeld, unpubl. ms.). Habitat Preferences of Puma It is now uncertain whether the job of estimating habitat preferences of resident puma can be completed. The time-consuming feature of the Marcum and Loftsgaarden (1980) method is the very large number of random locations required (5 to 10 times greater) than the number of actual locations. Manuscripts in Press and Publication Goals Two additional reports were completed and publication likely during the 198990 fiscal year (Anderson and Tully 1989, Anderson 1989). My intent is to complete a comprehensive, peer-reviewed publication prior to my retirement during November, 1990. LITERATURE CITED Anderson, A. E. 1983a. Program Narrative Proj. 45-01-503-15050, Work Plan 6, Job 1. Mountain lion population dynamics. 7pp. (+3 tables and Appdendix A). _____ 1983b. A critical review of literature on puma (Felis conco1or). Colo. Div. Wildl. Spec. Rep. 54. 9lpp. 1989. Sexing and aging mountain lion. (draft submitted.) Colo. Div. Wildl. S.O.P. , and R. J. Tully. 1989. Status report - Colorado. Proceedings Third National Mountain Lion Workshop, Prescott, AZ. (in press). �193 Anderson, A. E., D. C. Bowden, and D. M. Kattner. 1989. Dynamics of home range size of unhunted mountain lion (Felis conco1or hippo1estes) in southwestern Colorado. (abstract). Proceedings Third National Mountain Lion Workshop, Prescott, AZ. (in press). Anderson, A. E., D. C. Bowden, and D. M. Kattner. 1989. Survival in an unhunted mountain lion (Felis conco1or hippolestes) population in southwestern Colorado. Proceedings Third National Mountain Lion Workshop, Prescott, AZ. (in press). Marcum, G. L., and D. D. Loftsgaarden. 1980. A nonmapping technique for studying habitat preferences. J. Wildl. Manage. 44:963-968. Prepared by e ~~ ~ Allen E. Anderson Wildlife Researcher �194 Table 1. Numbers of aerial locations of 7 resident male puma radio tracked >12 months at aEEroximate weeklx intervals, 1983-88. Year 83 84 85 86 87 88 Pe r Lod" Period Period Period Period Period 1 2 1 2 1 2 1 2 1 2 1 2 All No. N N N N N N N N N N N N N 5 18 20 22 40 44 52 12 23 24 27 25 23 23 All 12 24 24 22 4 26 47 52 20 25 22 25 9 5 23 13 15 24 18 20 22 23 19 15 3 18 22 21 22 22 21 24 25 23 26 9 8 8 7 9 255 89 103 126 73 67 60 51 75 58 107 127 144 50 773 Mos. monitored 65.0 25.0 30.6 42.5 18.0 17.0 15.0 aperiod 1 - Large prey species mainly on winter and transitional ranges (Nov. 16 - May 15). Period 2 - Large prey species mainly on summer and transitional ranges (May 16 - Nov. 15). �195 Table 2. Numbers of aerial locations of 10 resident female puma radiotracked ~12 months at approximate weeklI intervals, 1982-88. Year 82 Perioda 1 2 N N No. 4 6 7 12 15 21 28 32 34 45 6 All 6 21 21 84 83 Period 1 2 N N 20 12 10 8 50 25 24 25 22 96 85 86 Period 1 2 N N Period 1 2 N N Period 1 2 N N 21 22 25 22 17 25 27 26 25 25 23 24 24 24 18 21 23 18 22 20 23 23 27 107 115 26 26 26 24 23 129 125 20 20 20 19 20 14 20 174 134 87 Period 88 Period 1 N 2 N 1 N 2 N 25 25 24 25 22 22 22 22 14 25 23 25 8 9 9 2S 22 1 25 22 1 22 15 22 167 175 25 9 25 25 23 184 9 9 8 61 All N Mos. monitored 270 255 257 248 110 122 38 119 57 68 1 544 85.2 65.0 64.2 63.7 27.0 42.S 12.0 30.1 13.0 17.7 aperiod 1 - Large prey species mainly on winter and transitional rang•• (Nov. 16 - May 15). Large prey species mainly on summer and transitional ranges (May 16 - Nov. 15). Period 2 - Table 3. Twelve male 9 female resident and nonresident puma whose aerial locations and inferred familial relationshiEs lend themselves to testins hz:egthesesrelative to interaction and disEersion. Approx. date No. mos. monitored when ~24 mos. within ase classes Age (mos.) Dates of locations attained Sex <24 mos. >24 mos.a No. at caEture First Last Male Female 8 13 14 23 26 35 38 42 47 50 55 17 6 10 84 12 10 6 36 12 9 13 30 8 2-25-83 4-15-83 12-16-83 1-14-85 3-22-85 2-17-86 12-19-86 1-16-87 1-30-87 2-20-87 2-12-88 4-20-84 8- 4-83 2- 3-84 6-22-84 11-22-85 2- 6-87 10-10-86 5-15-87 4-17-87 7- 8-88 2-12-88 7-14-88 7- 6-84 5.5 10.0 0.0 10.2 13.0 7.7 0.0 3.0 14.0 10.0 0.0 2.5 0.0 0.0 5.0 0.0 9.5 0.0 5.0 0.0 3.2 1.7 5.0 0.0 3 27 46 53 54 56 57 33 26 14 60 48 14 14 26 7 6 1-11-82 4-27-85 1-24-87 12-21-87 1-15-88 3- 4-88 4-15-88 2-10-86 2-17-86 4- 8-83 11-22-85 8- 5-87 7-14-88 7-14-88 7-18-88 7-14-88 11- 6-86 8- 9-87 0.0 6.7 0.0 0.0 6.0 4.0 0.0 9.0 17.0 5.0 0.0 6.5 6.7 0.0 0.0 3.0 0.0 1.7 36 a~24 mos. may b. the minimum age of reproductive activity in wild puma (Anderson 1983). 4-25-86 3-30-88 12-21-87 6- 5-87 �196 Appendix 1 (Abstract) DYNAMICS OF HOME RANGE SIZE OF UNHUNTED MOUNTAIN HIPPOLESTES) IN SOUTHWESTERN COLORADOa,b Allen E. Anderson, Colorado Montrose, CO 81401 Division David of Statistics, Donald C. Bowden, Department Collins, CO 80523 M. Kattner, of Wildlife, 63478 Ida Road, Montrose, LION (FELIS CONCOLOR 206 South 5th Street, Colorado CO State University, Fort 81401 Five adult female and 2 adult male mountain lion were radio collared and aerially located at approximate weekly intervals on Uncompahgre Plateau, over periods ranging from 23 to 49 months each. Home range size was estimated for years and periods using the minimum convex polygon (MCP) as an application of the nonparametric tolerance region (NPT) technique and by the harmonic mean (HM). Multiresponse permutation procedures were used to detect temporal differences in their spatial distribution, which were described by dispersion and median location concentration estimators. At the 90% confidence level, the proportion (P) of time 5 female puma spent within MCP regions of size (A, km2) were at least (P,A) (.908, 219.5), (.867, 140.0), (.873, 238.0), (.841, 186.0), and (.875, 128.0). During the period of maximum average female home range size (November 16 - May 15) (P,A) were (.793, 187.5), (.795, 92.0), (.713, 164.0), (.737, 175.5), and (.708, 104.5) at the 90% confidence level. Among female mountain lions, use was most concentrated during the heavy snowfall year of 1985 and during the May 16 - November 15 period. Shifts in location of females were more than twice as large between periods as between years. For the total sample of 519 female locations, median MCP and HM home ranges approximated 186 km2• Home range sizes (MCP) of 2 male mountain lions 2 were 596.5 km and 279.0 km2 who spent at least 0.842 and 0.790, respectively, of their time within those home ranges at the 90% confidence level. aA1though closed to sport hunting of mountain 1ipn in 1982, 11 mountain lions marked on the study area were killed, 1 illegal and 2 livestock depredation kills within the study area, and 1 illegal and 7 legal kills outside the study area. grants bContribution from Colorado from the National Wildlife In press, Federal Aid Project W-53-R assisted by Federation and Pope and Young Club. Proc. Third Nat1. Mountain Lion Workshop, Prescott, AZ, Dec. 1988. �197 Appendix SURVIVAL IN AN UNHUNTED HIPPOLESTES) POPULATION 2 (Abstract) MOUNTAIN LION (FELIS CONCOLOR IN SOUTHWESTERN COLORADO&,b Allen E. Anderson, Colorado Montrose, CO 81401 Division David C. Bowden, Department Collins, CO 80523 of Statistics, Donald M. Kattner, of Wildlife, 206 South 5th Street, Colorado 63478 Ida Road, Montrose, CO State University, Fort 81401 Twenty male and 21 fe~ale mountain lion were captured on a 3,263-km2 portion of the Uncompahgre Plateau and fitted with transmitters equipped with mortality switches, 1981-88. Gross approximations of their ages at capture based on dental and physical characteristics ranged from 2 to 84 months. Animals were monitored with aerial telemetry at approximate weekly intervals over periods ranging from 0.2 to 79 months per individual. The survival of each sex was examined separately by the life regression procedure (LIFEREG) in SAS which allows for censored observations (animals alive at the end of the study). Tests of goodness of fit for each sex between the Weibul1 and exponential models indicated that the Weibull model did not provide a significant improvement of fit over the exponential model. Sexes were combined because a statistical comparison of male and female data suggested similarity (Z - 1.006, P - 0.32) assuming an exponential model and mu1tiresponse permutation procedures (a nonparametric test) indicated that ages at mortality of each sex were similar. A Q-Q plot did not reveal any serious departure of the data from an exponential model. Thus, 25%, 50%, 75%, 90%, and 95% of male and female mountain lions have died by ± SE) 27.35 ± 6.27, 65.90 ± 15.12, 131.80 ± 30.24, 218.92 ± 50.22, and 284.82 ± 65.34 months of age, respectively. Fifty percent of the mountain lions died by 65.9 months of age with 95% confidence limits of 42.0 - 103.3 months. The annual survival rate was 88.1% with approximate 95% confidence limits of 82.1 - 92.3%. (x &Although closed to sport hunting of mountain lion in 1982, 11 mountain lions marked on the study area were killed, 1 illegal and 2 livestock depredation kills within the study area, and 1 illegal and 7 legal kills outside the study area. bContribution from Colorado Federal Aid Project W-53-R assisted by grants from the National Wildlife Federation and Pope and Young Club. In press, Proc. Third Nat1. Mountain Lion Workshop, Prescott, AZ, Dec. 1988. ��199 Colorado Division Wildlife Research July 1989 of Wildlife Report JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~ _ Project _ Mammals _ Small Carnivorous No. ~W_-~1~5~3~-R~-~3~ Work Plan No. Job No. Period __~8~A~ I Covered: Author: Personnel: July Research Mammal Investigations Development of River Otter Reintroduction Procedures 1, 1988 - June 30, 1989 T. D. I. Beck T. Benjamin, L. Malville, R. B. Gill ABSTRACT Seven river otters (Lutra canadensis) were received from Oregon Fish & Wildlife Dept. Six were released into the Dolores River and 5 survived. Radiotelemetry indicates winter ranges varied from 7-12 mi in length. All river otters nearly doubled range use in May-June by taking long excursions. One male disappeared in April, presumably downriver. A draft river otter recovery plan was submitted to the state office, with appendices covering the history of prior releases. A general survey of crayfish (Orconectes virilis group) was conducted over 99 mi of river. Catch per trap night was significantly different between 4 sections of the river. The upper 44 mi appear to have relatively high densities of crayfish. Turbidity was measured biweekly at 5 sites between RM 167 and RM 102 for 1 yr. Water temperature was recorded ··continuously for 1 yr at RM 127.3, with a 10-week break in service in mid-winter because of operator error. General habitat mapping of river ·bed components, bank components, and bank vegetation was completed at each 0.1 mi from RM 166.7 to RM 69.7. ��201 DEVELOPMENT OF RIVER OTTER REINTRODUCTION PROCEDURES Thomas D. I. Beck P. N. OBJECTIVE Develop procedures for river otter reintroductions in Colorado and establish a self-sustaining population of river otters from which to collect river otters for future translocations. SEGMENT OBJECTIVES 1. Introduce up to 20 river otters into the Dolores River drainage. 2. Monitor all river otter release past reintroductions. sites in Colorado to evaluate 3. Develop techniques to monitor survival, reproduction, dispersal of river otters after reintroduction. METHODS River Otter Recovery success dispersion, of and AND MATERIALS Plan A thorough review of North American and European literature was conducted, informal meetings with regional staff were held, and all available records from earlier Colorado releases were collected prior to preparing a draft recovery plan. Appendices were attached detailing the history and status of the 4 prior release sites: Cheesman Reservoir, Gunnison River, Piedra River, and N. Fk. Colorado (RMNP). Dolores River Release River otters were captured in Oregon and Alaska and kept at the Portland Zoo for periods of 3-26 days. All river otters were shipped on one flight conducted by Bob Allen of Project Lighthawk. The intent was to use a private plane to enable us to fly direct and avoid long layovers on commercial flights. Weather did not cooperate and a most circuitous route from Portland to Cortez was found. Upon arrival the animals were taken to Cortez Animal Clinic where David Herrick, D.V.M., conducted the surgery to place the intraperitoneal radio transmitters in place. Surgical procedures basically followed those outlined by Hoover (1984). The radio transmitters, Telonics Model 400, weighed 110 gms and measured 9.5 em in length and 3.2 em in diameter. Gas sterilization techniques were used on the transmitters at least 10 days prior to surgery. Initial immobilization was accomplished with intramuscular injections of ketamine (100 mg/ml) and xylazine (20 mg/ml) at a dose rate of 15 mg ketarnine per kg of animal. Halothane gas was used to maintain narcosis until surgery was complete. Following surgery each river otter was tagged with a Monel #3 metal tag in the web between 2 front toes and measured for total length; tail length; neck, chest and head circumference; and weight. All injuries were recorded and white blood cell count, hematocrit, and a fecal smear for parasites were checked. �202 Radio tracking of the released river otters was conducted from ground, canoe, and aerial searches, dependent on season, and occurred at least once each 5 days for each individual. Because of the steep canyon terrain, triangulation was not feasible so all signals were tracked to the source; either the animal or more usually a beaver (Castor canadensis) den. Locations were recorded by river mile to an accuracy of 0.1 mi. Prey Base Studies An impression from the 1987 fish surveys was that crayfish (Orconectes virilis group) were surprisingly abundant in some stretches of the Dolores River. A relative abundance survey was conducted between 14 and 29 July 1988. Large minnow traps (78 X 23 cm) with funnels at both ends were baited with 0.5 kg of Purina Crawfish Bait. Sample sites were at 1.0 mi intervals beginning at RM 167.7 and ending at RM 69.7. A single trap was set at each site and left for 24 hrs. All crayfish were sexed and carapace length was measured. A measuring board was built by gluing a 8 rom diameter dowel into a 5 X 20 cm board and gluing a clear plastic rule IS cm long against the dowel. The rostrum of a crayfish was placed against the dowel and a vertical sight taken at the end of the carapace. Carapace length was recorded to the nearest mm. The traditional way for measuring crayfish is to use calipers and record to nearest 0.1 rom and then report all data to nearest rom. The measuring board was much faster and proved sufficiently accurate. The statistic for comparing relative abundance was total number of crayfish per trap day. Habitat Studies River flows in cubic feet per second (cfs) were obtained below McPhee Dam (RM 179.5) from the Bureau of Reclamation, USDI. Water temperature was recorded at RM 127.3 with a Ryan Automatic Recorder and was tabulated at 2 hr intervals for each day. Turbidity was measured at 5 sites at biweekly intervals for 1 yr. Turbidity was measured in Formazin Turbidity Units (FTU) with a Hach Portable Colorimeter DREL/lC. Sample sites were at RM 166.8, 147.4, 124.3, 118.6, and 102.4. A general habitat survey was conducted at 0.1 mi intervals between RM 166.7 and RM 69.7. The survey consisted of 3 parts: river bed components, bank components, and bank vegetation. River bed components were: 1) primary habitat 2) secondary habitat 3) substrate 4) maximum stream depth 5) stream width 6) boulders 7) islands 8) bars. Primary habitats were main channel, chute channel, side channel, and tributary with only 1 type per site. Secondary habitats were run, pool, riffle, shoreline eddy, obstacle eddy, rapid, rubble flats, and backwater; and as many as 3 types might be present per site. Substrate categories were silt, sand, gravel, cobble, boulder, and bedrock with the 2 major substrates being recorded. Width was recorded as <11 m, 11-30 m, and >30 m. Boulder categories were none, large and inaccessible to river otters, and large and accessible to river otters. Island categories were none, head of island, main body of island, and tail of island. Bar categories were none, cobble, sand, silt, and boulder. Bank components were 1) bank configuration at high and low water 2) bank height at high and low water 3) bank stability 4) bank cover 5) logs 6) �203 beaver activity. Bank configuration categories were sandbar, cobblebar, <30 degrees, 30-60 degrees, >60 degrees, rock cliff, and sand cliff. Bank height was recorded as <1 m, 1-2 m, 2-3 m, and >3 m. Bank stability was rated as stable «10% sloughing), moderate (10-30 % sloughing), and unstable (>30% sloughing). Bank cover was rated as sparse, moderate, or dense. The categories were based on the probability of seeing a river otter at 5 m distance. Sparse cover would always allow one to see a river otter at 5 m, moderate cover could possibly hide the river otter but most likely not, while dense cover would always hide the river otter at 5 m. Log categories were none, single from bank to water, 1-5 logs from bank to water, debris pile, and submerged log island. Beaver activity was categorized as none, active slides, active slides and dens, inactive slides, and inactive slides and dens. Bank vegetation was inventoried following the procedures described by O'Brien and Van Hooser (1983). The plot was 30 m along the bank to a distance 10 m back from the bank. By using the plant cover categories of 1-5%, 6-25%, 2650%, 51-75%, 76-95%, and >95% the dominant vegetation could be recorded from a canoe in mid-river. Part I lists dominant species by group--trees, shrubs, forbs, and graminoids-- with no more than 4 species by group. Canopy cover must exceed 5% for a plant species to be recorded in this part. The vertical layer of each species was also recorded as Layer 1 «0.5 m), Layer 2 (0.5-2.0 m), and Layer 3 (>2.0 m). Part II provides a cover class rating for the entire plant group within each layer and includes plants not abundant enough to show up in Part I. However, there were no species specific values given in Part II. Bank vegetation was described from both banks at each site. RESULTS AND DISCUSSION River Otter Recovery Plan A draft river otter recovery plan for Colorado was submitted to the state office in November 1988. The plan included a brief historical summary, statewide objectives, and a 7-step program to achieve recovery of the species within the state. Four appendices were included covering the history of the earlier river otter releases at Cheesman Reservoir, Gunnison River, Piedra River, and the N. Fk. Colorado (RMNP). Dolores River Release Seven river otter arrived at Cortez at 2130 on 2 November 1988 (Table 1). Surgical implantation of radio transmitters, tagging, and measuring were conducted at the Cortez Animal Clinic with the last animal completed at 0330 on 3 Nov. Six animals were released at RM 139.7 on the Dolores River at approximately 0800. RO-6 never recovered from anesthesia. He was extremely lethargic when removed from the shipping crate prior to surgery; a noted contrast to the rather excited nature of the adult river otters. His WBC count and hematocrit were normal. Perhaps the ubiquitous demon of stress was the cause of death. Five of the river otters swam off quite vigorously upon release but an adult female, RO-2, stayed in the shipping crate for over an hour before moving off. She had very restricted movements and died on 5 November. She was a very sick animal upon arrival, suffering from foot injuries which included broken bones and chewing, and vaginitis. Her WBC was 29,000 and hematocrit was 32%. She was treated with 150 ml half-strength �204 lactated Ringer's solution and dextrose as well as 500 mg Kefzol. It was decided to release her rather than maintain her in captivity since many of her wounds appeared to be self-inflicted, possibly a response to captivity. Table 1. River otters released ID Length (cm} W'T Total Tail in the Dolores River, CO. Circumference (cm} Head Neck Chest Tag 1988 Age Sex RO-1 AD M 7.3 127 47 25 24.5 34.5 1 148.02 Cordova, AK RO-2 AD F 5.8 123.5 43 24 27 33 2 148.03 Cordova, AK RO-3 SAD M 5.4 woke up too soon 3 148.04 Laketown, RO-4 AD M 6.0 woke up too soon 4 148.05 Cordova, RO-5 AD F 8.0 116 40 25 28 40 5 148.06 Laketown, OR RO-6 JUV M 3.6 95 35 22 20 27.5 6 148.07 Laketown, OR RO-7 AD M 7.3 109 41 24 27 37 7 148.08 Laketown, OR # RT Freq Origin OR AK Of the surviving 5 river otters, the 2 Alaskan males have been quite difficult to keep up with. In the 30 day period post-release RO-l was only located 5 times and had moved 10 mi downstream while RO-4 was also located 5 times and also moved 5-10 mi downstream. RO-3 decided to try an overland route from the release site and climbed up the canyon wall until becoming ledged out at the base of a vertical wall of sandstone approximately 900 ft above the river. We packed food and water to him for 2 days in attempts to lead him down. Finally on 8 Nov. we captured him on the ledge and packed him down to the river in a shipping crate. He remained the remainder of the month within 5 mi of the release site and upstream. RO-5 and RO-7 spent most of the first month together in the area near the release site and up to 4 mi downstream. The reasons for the difficulty in locating the 2 Alaskan males are unknown but it is suspected they make frequent long movements and do not show a strong affinity for one area. Thus if one checks for them in a 10-mi stretch one day and then moves downriver the otters likely moved upriver through the 10-mi stretch overnight. Whatever the reasons, they have been difficult to follow. RO-1 was only located 24 times in 8 months and ranged from RM 124 to RM 143. He is still within the study area. RO-4 was only located 27 times in 6 months, ranging from RM 128 to RM 158. He has not been located since 20 April although extensive boat and aerial searches have been conducted of the entire Dolores River and much of the San Miguel River. A sighting of a river otter by a commercial rafter was reported in mid-May from RM 80 but the same week a search of RM 102 to RM 70 did not find sign or a radio signal. �205 RO-3 was located 108 times during the 8 months, ranging from RM 140 to RM 156. However, 103 of the locations were between RM 140 and RM 147.5. The 5 locations outside this area were in May and June and he went upriver to RM 155-156. RO-7 was located 93 times during the 8 months, ranging from RM 132 to RM 156 with over 80% of the locations being between RM 137 and RM 147. There were no locations from RM 148 to RM 155 and he was located in RM 155 several times during May and June. The female, RO-5, was located 57 times, ranging between RM 124 and RM 156. Fifty of the locations were in the stretch between RM 132 and RM 143. Her movements downstream of this core stretch occurred in May and the upstream movements occurred in June. The river otters were released approximately 3 weeks before most of the Dolores River iced up so it was not surprising to see relatively limited movements throughout the winter. In reviewing the radio telemetry data from the N. Fk. Colorado for the recovery plan it was found that the river otters there made extensive movements, usually downstream to the big lakes, in May and June. As spring flooding occurs during this period it was thought that the expanded movements were a response to that. Now on the Dolores River we see greatly expanded movements again in May and June. However, high water in 1989 was from 1 April to 15 May and then the flow was reduced to the base summer level of 78 cfs. All the long movements occurred after the drop in water. Expanded effort will be made in 1990 to closely follow all river otters in May and June to better document this pattern. All introduced river otters used beaver bank dens extensively. In winter it was not unusual for river otters to exit a beaver den under the ice, forage, then return to the den without ever surfacing. River otters could be using a pool for several days and never leave any surface evidence of their presence. Extensive use of beaver dens was even more noticeable during the hot summer months when most river otter activity was at night and the entire day was spent in the dens. Temperatures in bank dens have been shown to be nearly constant during the day and significantly cooler than ambient temperature during the summer and constant but warmer than ambient in the winter ( Buech et al. 1989). No attempt was made to assess food habits from scat collected and such activity will not be attempted until after the controlled feeding experiment. This experiment could not be conducted in 1988 because the river otters were received so late in the year. Our impression is that crayfish are utilized extensively in all months of the year. The only surprise is that crayfish hibernate under rocks throughout the winter and the river otters have shown expertise at digging them out. The most common fish remains found were heads from large channel catfish (Ictalurus punctatus). It is not known if this is because of selective predation on the catfish or because of the massive bony catfish head which cannot be eaten by river otters. Prey Base Studies First a note on the taxonomic status of the crayfish in the Dolores River. is not known if any species of crayfish was native to the Dolores River It �206 drainage and large scale trans locations of crayfish into the basin have occurred. The Colorado Div. of Wildlife placed crayfish, species unreported, into numerous reservoirs in the basin in 1956. Sampling of these reservoirs in 1988 found the species present was in the Orconectes virilis group. Crayfish were reported in the Dolores River during fish surveys in 1977 but none were collected. Additionally crayfish, ~ virilis group, were transplanted into McPhee Reservoir on the main stern of the Dolores River, in the mid-1980's by Colorado Div. of Wildlife. Not surprising then that our surveys of the river below McPhee Darn found ~ virilis group. This group is composed of 3 species which are morphologically nearly indistinguishable: ~ virilis, ~ nais, ~ causeyi (Fitzpatrick 1987). Discussions with H. H. Hobbs, Jr., of the Smithsonian Institute, resulted in an identification of "probable" ~ causeyi because of the geographic location. It was my impression that Dr. Hobbs actually thinks that all the beasts are just normal variants of ~ virilis. Because of the many translocations of crayfish with poor record keeping it is unlikely if this taxonomic problem will ever be resolved. Until resolution, the decapod in question will be called ~ virilis group in our reports. Number of crayfish caught per trap night was plotted against river mile and 4 distinct sections of the river were apparent. Section 1 was from RM 167.7 to RM 146.7 (Bradfield Bridge to Dove Creek Pump Stn.), section 2 was from RM 145.7 to RM 124.7 (Dove Creek Pump Stn. to Disappointment Creek), section 3 was from RM 123.7 to RM 95.7 (Disappointment Cr. to 7 mi below Little Gypsum Valley Bridge), and section 4 was from RM 94.7 to RM 69.7 (ending at BLM ramp upstream from Bedrock Bridge). Plotting of the data suggested non-normal, negative binomial distributions (clumping) so the Mann-Whitney U Test was used to compare the similarity of medians and distributions. In comparing the catch per trap day data (Table 2), the null hypothesis was that Section X has the same distribution and median value as Section Y. Section 1 was compared to Sections 2,3, and 4 with Ho rejected in all cases (p-0.05, 0.01, 0.001 respectively). Section 2 was compared to Sections 3 and 4 with Ho rejected both times (p-0.001 in both) and Section 3 was compared to Section 4 with Ho rejected again (p-0.001). Table 2. Crayfish caught per trap day among sections of Dolores River, 1988. Std. Error Section No. Sample Sites Median Range Mean 1 22 34.5 10-51 31. 8 12.8 2 22 49 1-106 51.2 30.6 3 29 17 1-46 19.7 11.4 4 26 2 0-21 3.3 4.6 Age classes of captured crayfish were estimated from graphic plots of frequency of lengths based on the 2,490 crayfish measured (1645 males, 845 females). Age classes will not be reported yet because I am not confident of �207 the class categories. Our data were so at variance with much of the information in the literature that I want to carefully reexamine our analyses. Such analyses have been hampered by changes in our library staffing that has slowed down procurement of hard-to-find papers. The most perplexing problem is the apparent large percentage of Age Class III in all sections but especially Section I. There are also apparent growth rate differences between sections. Work in 1989 will focus on studies of density, growth, and trap vulnerability of crayfish. What can we say about crayfish abundance in the Dolores River? Unfortunately, simple catch per unit effort data does not tell much about absolute abundance, which is really what is of interest to a river otter. However, some strong trends were apparent. I have no explanation for the differences observed between Sections 1 and 2. The river appears to be similar habitat for crayfish throughout these stretches. More large crayfish were caught in Section I and perhaps the aggressive nature of the larger animals in the trap kept others out. The sharp decline in captures below Disappointment Creek is most likely a reflection of changing habitat caused by the side canyon discharges in spring and late summer. The most noticeable changes below RM 125 are increased turbidity, warmer water temperatures, more sand and silt substrate, and the absence of green algae (Cladophora sp.). The influence of turbidity to crayfish is likely expressed through the consequent reduction in green algae and phytoplankton production. The catch in section 3 exceeded my expectations from prior work on the river. The morning following the flash flood on 31 August 1988, when the river rose 1.3 m vertically overnight and turbidity went up to 9,000 FTU's, crayfish were observed leaving the water and crawling into beaver bank dens. Groups of 5-30 crayfish could be seen in all the beaver dens. The river cleared up to less than 200 FTU's within 48 hrs and presumably the crayfish went back into the river at that time. Our knowledge of crayfish life history in the Dolores River is too scanty to allow the generation of causative explanations for the marked decline in catch in Section 4. The break does not occur immediately downstream of a major side canyon nor does the bank or substrate appear to change much. Another survey will be conducted in 1990 to compare to the 1988 findings. Perhaps that survey combined with the physical habitat survey will provide more clues. Habitat Studies Dolores River flows in 1988 strongly reflected the influences of the McPhee Dam and the 50% snowpack. The Bureau of Reclamation had maintained a base winter flow of 78 cfs until 28 April. Discharge was rapidly increased over 5 days to peak at 1200 cfs for the week of May 3-8 when it was dropped back to 194 cfs. On 18 Maya release of roughly 600-700 cfs was begun and continued through 7 June. By 18 June the base summer flow of 78 cfs was in force and continued throughout the year. In comparing the pattern to what might have been had there been no dam it is apparent that the minimum flows were greater throughout 1988 than would have been expected. The peak flow was close to the time and amount one would have had naturally. The biggest difference was the yo-yo pattern in May. The major impact to aquatic and riparian life was probably the sustained flows of 78 cfs throughout the summer. Water temperatures were continuously recorded at a point 52.3 mi downstream of the dam and 3.5 mi upstream of Disappointment Creek. This point was selected �208 based on the 1987 fish surveys and represents my estimate of the downstream end of trout habitat. The diel pattern for July 1988 showed an average daily minimum of 17.4 C and an average daily maximum of 21.8 C. The minimum temperature occurred at 1000 and the maximum at 1800. An average of 8 hrs per day had water temperatures exceeding 21 C but the mean is somewhat misleading as there was a mixture of 0-3 hr days with 10-12 hr days and few in between. The diel pattern for August was similar but with minima and maxima occurring 2 hrs earlier. Average daily minimum temperature was 16.6 C and average daily maximum temperature was 21.2 C. The average period above 21 C per day was less than 1 hr. September was a period of marked cooling with average extremes of 11.5 C and 15.4 C. An unusual pattern of warming was evident in that the water released from the reservoir varied substantially in temperature during the day and the water in the river rapidly reached maximums of 21 C but then maximum daily temperature did not increase much over the next 47 mi. Data from the Bureau of Reclamation, Durango Projects Office, was only available in graph form and this precluded more detailed comparisons. However, the daily variance in water temperature for the first 2 weeks of July 1988 could be compared at 3 sites: RM 174.6, RM 127.3, RM 116.8. Water temperature at the upper site, 5 mi below the dam, varied from 12-21 C while the site 52.3 mi below the dam varied from 16-22 C. The maximum daily temperatures were quite similar. At the lower site, 62.8 mi below the dam, daily variation was between 20 and 26 C. This pattern of warming likely will have an influence on spatial and temporal distribution of spawning fishes and most likely will displace spawning of some species downstream. Attempts will be made to obtain more complete data sets from BuRec and then to analyze possible impacts to the fishes currently living in the Dolores River. The influence of McPhee Dam was quite evident on the turbidity of the river down to the confluence with Disappointment Creek (Table 3). Tributaries above RM 127 contributed fairly clear water even during summer storms. Flash floods scoured Tree Frog Canyon several times in 1988 as evident by the 3 high readings in August at RM 124.3. The situation below Disappointment Creek is dominated by side canyon discharge with peak turbidity during spring runoff in low elevation drainages and during the August-September monsoon season. The major influence of the ephemeral side canyons is evident in turbidity and flow. Attempts by BLM hydrologists to correlate flows at Dolores (RM 191) with flows at Bedrock (RM 69) have been to no avail because of the large flow increases' from summer storms (D. Murphy, pers. comm.). The 2 largest events occurred on 31 July and 31 August 1988. The Dolores River came up 98 cm vertically during the first and 140 cm during the second at RM 102. These storms had no impact on the upper river. During the 31 Aug. storm no rain actually fell on the Dolores River channel, all came from tributaries. Certain anomalies like downstream stations being clearer on a day result from afternoon melt and the timing of sampling. I usually sampled the downstream areas first. The general habitat survey was completed and all data entered into a dBaseIII file. All data entry has been proofed and errors corrected. Approximately 6 mi of the river had to be duplicated in June 1989 to correct a technician error on a shrub species. No analyses have been conducted with this data base yet. The description of the data collected was provided in this report so that federal cooperators will know what data is available. �209 Table 3. Turbidity at 2-week intervals on Dolores River, CO. 1988-89 Date 7-16-88 8-01-88 8-16-88 9-01-88 9-16-88 9-30-88 10-16-88 10-31-88 11-15-88 12-01-88 12-15-88 1-07-89 1-20-89 2-04-89 2-16-89 3-02-89 3-17-89 4-02-89 4-19-89 5-02-89 5-15-89 6-01-89 6-18-89 7-09-89 RM 166.8 8 0 8 4 8 12 2 2 2 2 2 8 1 2 10 8 10 12 19 8 4 2 1 4 FORMAZIN TURBIDITY UNITS RM 118.6 RM 147.4 RM 124.3 8 18 16 15 19 15 8 8 8 10 8 6 5 8 10 9 25 16 19 20 5 4 6 8 21 615 35 270 200 30 10 12 12 10 10 10 8 15 18 14 95 30 45 22 7 10 10 15 28 1240 40 3600 520 30 12 19 38 13 13 14 24 80 28 500 1300 135 160 25 14 16 12 28 RM 102.4 55 5500 75 9000 1010 35 13 19 275 14 15 18 22 80 26 1250 900 175 575 40 25 24 21 40 LITERATURE CITED Buech, R. B., D. J. Rugg, and N. L. Miller. 1989. Temperature in beaver lodges and bank dens in a near-boreal environment. Can. J. Zool. 67: 1061-1066. Fitzpatrick, J. F., Jr. 1987. The Subgenera of the crawfish genus Orconectes (Decapoda: Cambaridae). Proc. BioI. Soc. Wash. 100(1):44-74. Hoover, J. P. 1984. Surgical implantation of radiotelemetry devices in American river otters. J. Am. Vet. Med. Assoc. 185(11): 1317-1320. O'Brien, R. and D. D. Van Hooser. 1983. Understory vegetation inventory: an efficient procedure. Res. Pap. INT-323, USDA For. Ser. 6 p. Prepared by Thomas D. I. Beck Wildlife Researcher ��211 Colorado Division of Wildlife Wildlife Research Report July 1989 JOB PROGRESS REPORT State of Colorado Project No. _W~-~1~53~-R~3~ _ Mammals Research Work Plan No. ~9~A~ _ Elk Investigations Job No. 1 Impact of Elk Winter Grazing on Livestock Production and Work Plan No. 3~ Job No. 5 _ Period Covered: July 1, 1988 - June 30, 1989 Author: N. T. Hobbs, D. L. Baker Personnel: G. Bear, M. Miller, A. McIntosh, R. Reid, L. Carpenter, B. Gill, B. Petch, C. Woodward, B. Seely, H. Seely, L. Lovett ABSTRACT Elk grazing during winter influenced forage production and cattle performance on sagebrush-grassland range during spring. The magnitude of that influence depended strongly on year for cattle responses, but was largely independent of year for vegetation responses. Elk grazing caused linear declines in weights of cows and calves at the end of the spring grazing season· during years 2 and 3 of our studies. These declines resulted·from reductions in rates of daily gain and from treatment-:-induceq. delays in calf birth dates. During year ~.and 3, birth dates of cal.ves whose . mothers werei-n the high density eik treatment during the previous year occured an average of 4-6 days later than birth dates of calves whose mothers were in controls. During all years we observed linear declines in the standing crop of live and dead perennial grass in relation to elk density. Utilization of dead perennial grass approached 80% in the high density treatment during year 2 and 3. Utilization of live perennial grass reached an asymptote at about 20% for the moderate and high density treatments during all years. Although we occasionally observed a weak stimulation of primary production of grasses and forbs by elk grazing during year 1, the overall influence on.production was negligible. Large differences in precipitation among year interacting with the cumulative effects of cattle grazing were apparently responsible for marked annual differences in forage production and cattle performance. ��213 IMPACTS OF WINTER GRAZING BY ELK ON CATTLE PRODUCTION P. N. OBJECTIVES 1. To test the hypothesis that elk grazing during winter influences productivity and botanical composition of herbage on sagebrush grassland ranges during spring. 2. To test the hypothesis that elk grazing during winter influences the body weights and rates of gain of cows and calves using sagebrush grassland ranges during spring. METHODS the AND MATERIALS Study Area We conducted experiments on the Little Snake Wildlife Management Area in northwestern Colorado (township 9 north, range 95 west, sections 9, 10). The area is about 35 km (19 mi) north of Maybell, Colorado on County Road 19. Although this area does not typically contain high concentrations of elk during winter, it is representative of areas that do have those high densities. Topography of the area includes level ridge tops, rolling hills, and deep gullies, ranging in elevation from 1800 to 2000 m (5900 to'6600 ft). Aspects are southern and southwesterly with an average slope of 15 degrees. Soils are generally sandy and sandy loam. Climate of the area is dry and cold. The growing season averages only 81 days. Annual mean temperature is 6.06 C (42.9 F). Annual precipitation averages 27.5 cm (12.5 in). Vegetation is dominated by big sagebrush (Artemisia tridentata) with an understory predominated by needle and thread (Stipa comata), western wheatgrass (Agropyron smithii), Indian ricegrass (Oryzopis hymenoides), Junegrass (Koleria cristata), and cheatgrass (Bromus tectorum). Important forbs include wallflower (Erysimum asperum), peppergrass (Lepidium perfoliatum), silver lupine (Lupinus argenteus), and scarlet globe mallow (Sphaeralcea coccinea). Experimental Design We observed effects of elk grazing on forage and cattle response in a randomized complete block design with four levels of elk density (0 elk/kmz, 8 elk/kmz, 15 elk/kmz, and 31 elk/kmz) and three replications per level. There were three blocks, each consisting of four pastures. Each pasture within a block was stocked with one level of elk density such that each block contained all levels. During year 1, the twelve available pastures were blocked by pretreatment biomass of perennial grasses with the four lowest grass biomass pastures forming one block, and the four highest grass biomass pastures forming a second block, and the remaining four pastures serving as the third block. The four levels of elk density were randomly assigned to pastures within each block during year 1. �214 Procedures We stocked pastures with elk in December and January 1987-89. Average date of release into pastures was January 3. All elk were removed from pastures during April 18-21. Overwinter mortality approached 15% in the high density pastures, but was nil in the medium and low density ones. Healthy animals were for those in pour nutritional condition to minimize mortality and to maintain a consistent stocking rate across replications. We introduced 7 cow-calf pairs and one dry heifer into each pasture on May 9, 1989 and removed them 3 weeks later. This represents a departure form previous years when animals remained in the pastures for 6 weeks. However, a marked reduction in forage production compelled us to reduce the stocking rate this year in order to preserve consistent utilization rates in control pastures. With the exception of the heifers and replacements required by death losses etc, cows during year 3 were the same animals we observed during year 2 and were assigned to the same pastures they were in previously. We observed the birth dates of all calves and weighed them to the nearest 0.05 kg immediately after birth. Cows and calves were weighed to the nearest 1 kg when they were introduced to pastures and were reweighed 3 weeks later when they were removed. We estimated canopy cover of herbs shrubs immediately after removing cattle from pastures. Cover was estimated from the summed length of interception by each plant along 30 12m transects randomly placed in each pasture during year 1. We estimated standing crop, productivity, and utilization of forbs, perennial grass, and annual grasses by harvesting samples from 40 pairs of 0.70 m 2 plots in each pasture on each of three sample dates. Pastures were sampled immediately after the elk were removed (April 2729), at the midpoint of the spring grazing season (May 30-June 1), and at its end-(June 30-July 2). Samples were dried at 60% for 48 hrs, separated by hand into live and dead, and weighed to the nearest 0.01 g. We used a repeated measures analysis of covariance to analyze weight responses of cattle. Calf birthweight was used as a concomitant observation for calf weights out of pastures and for rates of gain. Cow weights into the pastures were used similarly for adult cattle and heifers. We believe that this analysis offers conservation tests of hypotheses because any cumulative, depressing effect of treatment on the covariate would tend to make it more difficult to detect significant differences among treatments. When use of covariance improves the sensitivity of analyses, we can conclude that this improvement results primarily from reducing experimental error. Vegetation responses were analyzed with a repeated measures analysis of variance for a randomized complete block design. In the future, we plan to use pretreatment biomass of forage as a covariate to improve precision in these analyses. �215 RESULTS All results described in this report are preliminary and are subject revision as analyses are checked for accuracy. Here, we report our findings to provide a timely summary of progress, but we are obliged thoroughly revisit them later. Effects to to of Elk on Cattle Performance Elk grazing during winter influenced the performance of cattle during spring, and the magnitude of that influence depended on year. Weights of cattle at the end of the grazing season during years 2 and 3 declined in direct proportion to elk density (Fig. 1). This decline in final weight resulted from the effects of treatment on cow rates of gain during spring (Fig. 2). We observed no such effects during the first year (linear effect P > 0.78). Average weights of cows at the end of the grazing season as well as rates of gain were substantially lower during the third year that during the first two (Fig. 1, 2). Effects of year were observed across all treatments, including the control, and hence can be attributed the effects of drought and to the cumulative effects of cattle grazing rather than to cumulative effects of elk grazing (year x treatment P-0.28). We observed significant linear declines in calf weights at the end of the grazing season during all years (Fig. 3). These effects approached significance (p-0.06) when the effects of birth weight were removed and were highly significant (p-O.Ol) when the effect of birth weight was included in the analysis. Effects of elk density on calf weights out of the pastures resulted in part from effects of treatment on calf rates of gain (Fig. 4, linear effect P - 0.07) and resulted partially from treatment-induced delays in birth date (Fig. 5, linear effect P-0.08). Calves during year 2 whose mothers were in the high density treatment during year 1 were born an average of 4 days later than calves whose mothers were in the control and were born an average of 6 days later the following year. (linear effect P-0.10). During years 1 and 2, birth weights of calves tended to decline relative to elk density (Fig. 6 P < 0.10) However, this tendency resulted at least in part from a spurious effect of the initial randomization. On average, larger calves were assigned to the control and low density pastures than to the medium and high ones. These assignments resulted purely by chance. That is, there was no opportunity for treatment to affect birth weights of calves during year 1. This effect emphasizes the importance of removing birth weight from the effects of treatment on subsequent weights. The linear effects of treatment on birth weight did not persist in year 3 (P - 0.52); however cows in the control still tended to produce larger calves than those in the treated pastures (Fig. 6 P-0.12). It is unclear whether this persistent effect id due to the initial randomization or to impacts of treatment. However, when significance is detected in subsequent weight responses (e.g. weight out of pastures) when the effects of birth weight are removed by covariance, we can be confident that those responses result from treatment. �216 Effects of Elk on Vegetation Of all begato responses, elk grazing during winter had greatest impact on the residual biomass remaining from the previous years growing season. During all years, elk grazing reduced the standing crop of residual perennial grass (Fig. 8 P~O.02) as well as the residual herbaceous biomass (forbs + annual grass + perennial grass, Fig. 9, P-0.02). These reductions were proportional to density. Standing crops of residual forage declined with year (Fig. 8, 9) but the effect of treatment did not depend on year for either response (P>0.45). Effects of elk density on live forage available to cattle at the beginning of the spring grazing season only approached significance (Fig. 10, 11, P<0.13). We observed no effect of treatment on production of perennial grass or total herbs (Fig. 12, 13), but production consistently declined with year across all treatments (year x treatment P - 0.78). We attribute this decline to effects of drought interacting with cumulative effects of cattle grazing. Effects of elk grazing on standing crops of perennial live and dead perennial grasses resulted from differences in rates of utilization during winter. At the highest densities, elk used about 50% of the residual biomass of perennial grass and total herbs (Fig. 14, 15) and used up to a third of the live biomass that was available at the beginning of the spring grazing season. Elk use accounted for as much as 25% of the total forage produced during the growing season (Fig. 16, 17). The combined effects of elk and cattle utilization of dead perennial grass and herbaceous biomass increased with increasing elk density during all years (Fig. 18, 19). However, we saw no effect of elk density on total utilization of live biomass except for perennial grasses during year 2 (Fig. 20, 21). The proportion of the total utilization of perennial grass that resulted from elk grazing increased with density and year (Fig. 22). Despite reducing the stocking rate from 7 to 14 acres per animal unit month during year 3, total utilization in the control pastures remained relatively constant with year (Fig. 18, 19, 20, 21). The absence of treatment effects on total utilization of live forage resulted from relatively constant utilization of live biomass by cattle across all treatment levels during year 1 and 2 and declines in use during year 3 (Fig. 23, 24). These patterns in utilization were driven by differences in removal of live forage by cattle, which tended to decline relative to treatment, particularly during year 3 (Fig. 25, 26). We observed pronounced effects of elk density on cattle removal of standing dead forage (Fig. 27, 28). Apparently, elk grazing can reduce the availability of live and dead perennial grass to the point that cattle substitute other forages in their diets, or reduce their total intake. During year 1, elk grazing reduced the average canopy cover of vegetation present at the end of the spring grazing from 47% in the control to 31% in the high density treatment (Fig. 29). During subsequent years we observed no effect of treatment except during year 3 when controls tended to have higher canopy coverage than other levels (Fig. 29). Canopy cover declined sharply between years 1 and 2, but �217 remained relatively constant at about 22% thereafter. Of all forage classes, annual grasses declined most steeply in response to treatment and year, declining from a high of 10.8% in the controls during year 1 to virtually 0 in all levels during the third year (Fig. 30). Perennial grasses tended to increase in coverage at intermediate levels of grazing during all years (Fig. 31, P-0.07) and declined sharply at treacment all levels as the study progressed. During all years, shrub canopy cover was higher in the controls than in the treatments grazed by elk (Fig. 31). We observed no consistent effects of elk grazing on canopy coverage of forbs, but did see strong effects of year (P-0.03) DISCUSSION A tendency for elk grazing during winter to reduce the performance of cattle during spring has clearly emerged in our studies during 1988-89. However, although this pattern was substantially more clear than it had been in previous years, there were several responses that nevertheless only approached statistical significance. This emphasizes the imperative need to continue our measurements to assure that our tests of hypotheses offer unambiguous results. That is, we wish to avoid failure to reject null hypotheses as a result of inadequate temporal replication. Forage production and canopy coverage data from control pastures revealed substantial impacts of serial drought interacting with cattle grazing in determining vegetative responses. Although this trend has made our job more difficult and has required us to adjust 'cattle stocking rates, we believe it is a fortunate outcome for our studies. The effects of elk grazing will be more economically and ecologically significant when forage supplies are limited. Because annual variation in forage availability due to variation in can consistently be expected on semi-arid rangelands, we are please that studies happened to coincide with a period of forage scarcity. This coincidence will allow our results to be far more relevant to policy decisions than they would have been if we had only been able to observe abundant forage conditions. The reduction of standing dead perennial grass that resulted form elk grazing appeared to be one the most important determinants of system responses. We surmise that this was the case because residual biomass represents an important "buffer" against forage scarcity during the growing season. Thus, although elk grazing had no discernable impact on the rate of forage production, its effect on the standing crop of live and dead forage was apparently sufficient to drive discernable differences in cattle performance. Prepared by Wildlife Researcher Dan L. Baker Wildlife Researcher �218 .-;t 460 '· I<.. -!-50 <1l ; 440 -'in 0...~ 430 ._ <, 0 I ...._..···_·····-1·········· .._.._._.... 420 - .•...••..•.•......•.•...•.•..•.......•...... -' 0 410 -' -= 'Q) 400 l---------t------+___________ I QD == ~ 390 u ~ 380 0 --- o: ....;: 370 5 0 10 15 20 25 30 35 Elk Density (animals/km2) IYear Means adjusted Contrast v. v. v. v. v. v. v. v. Year 1 eontro~ other. control. 8 .l.lc/1aa2 15 _l.lc/_ control. control. 31 _l.lc/Ial linear err.eta quadratic .rrect. v. v. v. v. Y_r 2 control other. control. 8 .l.lc/~ eontrol 15 .l.lc/_ contro.l 31 .l.lc/Ial lin •• r .r~.ct. quadratic _rr_eta v. v. v. v. Y.ar 3 control. others control. 8 .l.lc/~ 15 _l.lc/Ial control. control. 31 .1.1c/_ lin.ar •rrecta quadratic _rrecta to common 3 weight into pasture. Contrast ss M_an Square 1 1 1 1 1 1 539.563509 198.853090 65.917054 1202.530974 1103.359103 35.157516 539.563509 19••853090 65.917054 1202.530974 1103.359103 35.157516 1.42 0.52 0.17 3.17 2.91 0.09 0.2777 0.4960 0.6911 0.1251 0.138. 0.7709 1 1 1 1 1 1 0.519559 26.513162 99.655.10 43.550571 16.47••62 110.549671 0.519559 26.513162 99.655.10 43.550571 16.478862 110.549671 0.00 0.13 0.51 0.22 0.0. 0.56 0.9607 0.7260 0.5031 0.6544 0.7819 0.4816 1 1 1 1 1 1 724.70973 2.4.92550 261.59071 10.1.60889 977.07580 13.69219 724.70973 284.92550 261.59071 10.1.60.89 977.075.0 13.69219 5.06 1.99 1.83 7.55 6.82 0.10 0.0655 0.2080 0.2252 0.0334 0.0400 0.7676 1 1 1 1 1 1 15••55129. 5.73953. 61.959127 423.377231 493.53479. 11.944060 15••551298 5.739538 61.959127 423.377231 493.53479• 11.944060 1.01 0.04 0.39 2.69 3.13 0.0. 0.3544 0.8549 0.5536 0.1522 0.1271 0.7922 DP Al.l. Year. eontrol. other. eontro~ 8 .l.lc/~ eontro~ 15 _l.lc/_ control 31 .l.lc/Ial 1in_ar errect. quadratic .rr.eta 1 ....- ...•., 2 ----- P Va~u. Pr > P Figure l. Effects of elk grazing on average weights of cows at the end of the spring grazing season. Means are adjusted to remove the influence of weights at the beginning of the season. Vertical bars give ± 1 standard error. Tests of specific hypotheses are shown in the table of orthongonal contrasts. �219 - 2 >. al "C <, ~ ~ •.. ...•..• i1) - •...........•............... -------+ ··················f····· J------ _ 1 al c, .:: ~ C!! . ------- ---_---1 (/l :Il ............................ I 0 -_ -_ 3: 0 U ::a \/J ...• o 5 15 10 20 25 30 35 Elk Density (animals/km2) I Year Means adjusted Contrast DP Year. control v. others control v. .~k/kw.2 control v. 15 .~k/Icoo control v. 3~ .~k/Icoo linear _:tracts quadratiC .~~ecta 1 1 1 1 1 Y.ar 1 control v. other. control •.lk/1ca2 c::ontrol v. 15 .~k/Icoo control 31 •.lk/Ic:a lin.ar e~~ecta quadratic .~~.cta 1 1 1 1 1 Y.ar 2 control v. others contro.l 8 .1k/kw.2 control vs 15 .1k/1coo control v. 31 .~k/Icoo ~in_'" .~~ecta quadratic .~~.cta A~~ • v. • v. v. v. v. Y.ar 3 control other. control. v. 8 .~k/1ca2 control v. 15 .~k/Ic:a control 31 .~k/Ic:a lin.ar .~~ecta quadratic .~~ecta ~ Contr••t ss 1 .- ....- •.. 2 ----- to common weight into pasture. Xean square po Value L22 Pr > P 0.4.0713 .•.• 0.13.61138 0.05999403 0 •.•• 0713 .• 4 0.1386~138 0.05999403 ~.16.72259 1.~20.3.92 0.0.• 9720.9 0.049720.9 2.9. 2 ••6 0.~3 0.73"1 0.09414.10 0.0000026. 0.0176826" 0.09043016 0.026.0733 0.0085564. 0.09"14810 0.00 0.15 0.75 0.22 0.07 0.78 0.9964 0.71"9 0.4~97 0.6539 0.7989 0.4109 1 1 1 1 1 1 0.3702,,713 0.16"30520 0.1233300. 0.53.65963 0.47077113 0.00752465 0.37024713 0.16"30520 0.1233300& 0.53865963 0.47077113 0.00752465 4.26 1.&9 1.42 6.19 5.41 0.09 0.0847 0.21.5 0.278. 0.0"73 0.0590 0.7786 1 1 1 1 1 1 0.352.9471 0.01134.6. 0.13970791 0.95025955 1.11321026 0.02759750 0.352.9471 0.01134.6. 0.13970791 0.95025955 1.11321026 0.02759750 1.00 0.03 0.39 2.6. 3.14 0.0. 0.3567 0.&63. 0.5530 0.1525 0.1266 0.7.95 1 0.0000026. 0.0176.26.• 0.09043016 0.026.0733 0.00.55648 3 1.~6872259 1.120.3.92 0.35 0.15 0.310. 0.5740 0.7093 0.1352 0.1"20 Figure 2. Effects of elk density on average daily gain of cows during the spring grazing season. Means are adjusted to remove the influence of weight at the beginning of the season. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �220 - 100 -•• I:U) ..!I: <lJ !---.-.-..·.·..... 90 :;, ··.I I " - _.... ....J 7l ] ·················1 :'il Q., 80 '0 ....J :;, C ...J ---_ ..:: 70 .- I:U) <lJ li= ':tI u ::E 60 ----------_ --1 \I'J ....• o 5 15 10 25 20 30 35 Elk Density (animals/km2) I Year --- 1 Means adjusted Contrast DF All Year. control other. control 8 elk/02 control 15 elkin control 31 elkin linear .rrect. quadratiC e~~ecte v. v. v. v. v. v. v. v. Y.ar 1 control others control 8 elk/02 control 15 elkin control 31 elkin lin.ar .~1!ect. quadratic e~~ecta 1 1 1 1 1 1 Contrast ss _ 2 ----- 3 to common birth weight. lIeanSquare 86.3.76491 86.3876491 1••4070203 18.4070203 26.0353602 26.0353602 17••8624231 17••8624231 181..1.1.54137181.1154137 1.0260403 1.0260403 P Value Pr > F 2.49 0.53 0.75 5.1.5 5.21 0.03 0.1659 0.4941 0.4200 0.063. 0.0625 0.8692 1 1 1 1 1 1 9.3496115 4.5452424 25.3253283 21..0622934 39.7246.30 1..0022327 9.3496115 4.5452424 25.3253283 ;;11.062293" 39.72.• 6.30 1.0022327 0.31 0.15 0.84 0.70 1.32 0.03 0.5978 0.7113 0.39.•• 0.435" 0.29.•• 0.8614 Year 2 other. control control 8 elk/02 control. 15 elkin control 31 elkin lin.ar e~rect. quadratiC e~r.cta 1 1 1 1 1 1 14.3580781 2.2623351 2.2369114 39."620550 ..0.9202607 2.3"16."5 1".3580781 2.2623351 2.236911.• 39."620550 .• 0.9202607 2.3.• 168.• 5 0.75 0.12 0.12 2.05 2.12 0.12 0."211 0.7"35 0.7.•.• 9 0.2023 0.1953 0.7393 Y_r 3 control other. control 8 .lk/n2 eontrol 15 elkin control v. 31 ·:UC/a lin.ar e~~ecte quadratiC .~recte 1 1 1. 1 1 1 .5.592.• 6. 64.9"6494 5.33.• 7 .• 2 151.120379 112.575111 1.501."01. .5.592468 7.5" 5.72 64.9"6494 0 •.• 7 5.334742 13.30 151.120379 11.2.57511.1. 9.91. 0.1.3 1.501401 v. v. v. v. v. v. v. 0.0335 0.0539 0.5187 0.0107 0.0199 0.72.6 Figure 3. Effects of elk density on average weights of calves at the end of the spring grazing season. Means are adjusted to remove the influence of birth weights. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �221 1.011] ~0.961 ~0.911l If······· ...........j 1 I·· .!t: -;0.861 •• ........... .30.811 ;' ;' 'J) ~ ............ <, :tl c, 0.761 / ........;' .~ 0.711 ~ C-' 0.661 . ;'.... ;';'........ ;';' . .•...•.. ' . . . <,.•.. """''- / I := 00.611 ~ 0.561 o 5 10 15 20 25 30 35 Elk Density (animals/km2) I Year 1 Means adjusted Cont.rast 3 to common birth weight. DP Contrast ss ]. ]. ]. 0.0],7].7905 0.0].036040 0.000],2449 0.0530949], 0.044],],54. 0.00903823 0.0].7].7905 0.0],036040 0.000].2449 0.0530949]. 0.044].].548 0.00903.23 1.&6 ],.],2 0.0], 5.75 4.78 0.9& 0.22],4 0.330], 0.9].],3 0.0534 0.07].4 0.3606 0.00422800 0.00002394 0.00043785 0.0],78],042 0.020824],0 0.00299605 0.60 0.00 0.06 2.53 2.96 0.43 0.467& 0.9554 0.8],],4 0.],62. 0.],362 0.5383 A~~ Vear. control v. other. control v. 20 al.k/.q control v. 40 al.k/sq control. vs 80 a~k/.q 11near .:t~ect. ]. ]. quadratic ]. arracta 2 ----- Mean square F Value Pr > P Year ]. control v. others control v. 20 al.k/.q control v. 40 a~k/sq control v. 80 a~k/.q linear e:tr.ct. ]. ]. ]. ]. ]. quadratic ]. 0.00422&00 0.00002394 0.00043785 0.0],78].042 0.020824],0 0.00299605 ]. ]. ]. ]. ]. ]. 0.006],0].05 0.00543534 0.00046.39 0.00920845 0.00630068 0.00000].80 0.006],0],05 0.00543534 0.00046839 0.00920845 0.00630068 0.00000].80 ],,],4 1.02 0.09 ]..73 ]..].8 0.00 0.3259 0.35],6 0.7769 0.2368 0.3],87 0.9859 ]. 0.00703680 0.00954],56 0.00383068 0.02879422 0.0],963].4], 0.0],],79],44 0.007036.0 0.00954].56 0.003.306. 0.02879422 0.0].963].4]. 0.0].].79].44 ]..30 ]..76 0.7]. 5.3], 3.62 2.].7 0.29.0 0.2329 0.4328 0.0607 0.],057 0.],907 Yaar .rracta 2 control. v. other. control v. 20 .~k/.q control v. 40 al.k/.q control 80 a~k/.q lin.ar _:tract. v. quadratic arract. Y.ar 3 control. v. ·other. control 20 a~k/.q control v. 40 a~k/.q control 80 a~k/.q lin •• r arracta v. v. quadratic arracta ]. ]. ]. ]. ]. Figure 4. Effects of elk density on average daily gain of calves during the spring grazing season. Means are adjusted to remove the influence of birth weights. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �222 05/08,--------------------------------- __ ~ ;>, ~ 04/28 <, --c' o,... ... r~~~~~~_t--~~~~~~----------------i ... ~ 04/18 -' (tI Q ..c ......•.••...•...•.•. -' ... - ::04/08 ······£·····....··....····..····..·····..···..····I (tI U o 5 10 15 20 25 30 35 Elk Density (animals/km2) !Year contra.t AJ.l.Year. others control control 8 el.k/Jca2 ],5 el.k/Ino control. control v. 3]. el.k/Ino l.inea.re:t!:t!.ct. .:t!:t!eeta quadratic v. v. v. v. v. Year ]. other. control control v. 8 el.k/Jca2 ],5 elk/Ino control. cont.J:'ol. v• 31 el.k/Ino lin •• r •:t!:t!ecta quadratiC e:t!:t!ecta Y.ar 2 control v. other. control. 8 elk/ka2 control. 15 .l.k/Ino control 31 elk/Ino l.inear e:t!:t!ecta quadratic .:t!:t!ecta v. v. v. Year 3 control other. control 8 .1k/ka2 control v. 15 .l.k/Jca control v. 31 .l.k/Jca linear e:t!:t!ect. quadratic .:t!:t!.eta v. v. 1 .•.••-.•.•.. 2 ----- or Contrast ss Mean Square ]. ]. ]. 90.75000000 34.72222222 72. OOOOOOOO 80.22222222 72.8642857]. 28.2857].429 90.75000000 34.72222222 72. OOOOOOOO 80.22222222 72.8642857]. 28.2857],429 ]. ]. ]. F Va~u. Pr > P 5.66 2.].6 4.49 5.00 4.54 ]..76 0.0549 0.].9].7 0.0785 0.0667 0.077]. 0.2326 0.6944444 6.0000000 2.6666667 8.1666667 17.2023810 1.5779221 0.6944444 6.0000000 2.6666667 8.1666667 17.202381.0 1.5779221 0.].]. 0.93 0.41 1..27 2.67 0.24 0.7539 0.3719 0.5438 0.3033 0.1534 0.6383 1 1 1 1 1 1 42.2500000 54'0000000 16.6666667 20.1666667 7.2023810 20.3658009 42.2500000 54.0000000 16.6666667 20.1666667 7.20238],0 20.3658009 ]..31 1..68 0.52 0.63 0.22 0.63 0.2958 0.2431 0.4991 0.4590 0.6531 0.4569 1 1 1 84.0277778 28.1666667 80.6666667 66.6666667 63.2595238 35.4632035 84.0277778 28.1666667 80.6666667 66.6666667 63.2595238 35.4632035 4.51 ]..51 4.33 3.58 3.39 ]..90 0.0779 0.2650 0.0827 0.].075 0.],],50 0.2170 ]. ]. 1 1 1 1 ]. 1 ]. 3 Figure 5. Effects of elk density on birth date of calves. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �223 38.0,,-----------------------------------------, 37.0] I 36.0, i I j 35.01 ....; == I I 34-.0, j : ,~ 32.0i ~ 1 ------.f ··"'-<::: , I -- ------ --- -................. ] ;: 33.0j I I 31.0 30.0 o 5 10 15 20 25 30 35 Elk Density (animais/km2) 1 /Year Contrast A~~ Years control vs others control va 8 e~k/kla2 control VB 15 ••~k/kla control vs 31 e~k/kla linear erfecta quadratic erfecta OF Contrast S5 Mean Square 2 ----- F Value Pr > 3 F 1 1 1 1 1 1 22.71210354 10.28149578 11.10698537 26.36201103 22.76904171 2.47885934 22.71210354 10.28149578 11.10698537 26.36201103 22.76904171 2.47885934 8.38 3.79 4.10 9.73 8.40 0.91 0.0275 0.0994 0.0894 0.0206 0.0274 0.3759 control vs others control va 8 e~k/k1a2 control va 15 e1k/kla control VB 31 e~k/kla linear e~fect8 quadratic effects 1 1 1 1 1 1 9.3578780 4.0265907 1.8530518 17.0176295 15.0600917 0.0379540 9.3578780 4.0265907 1.8530518 17.0176295 15.0600917 0.0379540 2.30 0.99 0.45 4.18 3.70 0.01 0.1804 0.3585 0.5251 0.0869 0.1028 0.9262 Year 2 control VB others control. va 8 elk/kla2 control va 15 elk/kla control va 31 e~k/kla linear effects quadratic effects 1 1 1 1 1 1 3.23735720 0.11659716 1.4078.233 8.29033618 9.71352236 0.16260247 3.23735720 0.11659716 1 ••0784233 8.29033618 9.71352236 0.16260247 1.60 0.06 0.69 4.09 4.79 0.08 0.2534 0.8185 0.4368 0.0897 0.0713 0.7866 Year 3 control va others control va 8 elk/kla2 control va 15 e~k/kla control va 31 elk/kla linear effects quadratiC effecta 1 1 1 1 1 1 11.5337773 10.2763934 10.3982832 3.5664152 1.6063703 11.0560698 11.5337773 10.276393. 10.3982832 3.5664152 1.6063703 11.0560698 3.28 2.92 2.95 1.01 0.46 3.14 0.1203 0.1384 0.1365 0.3531 0.5246 .).1268 Year 1 Figure 6. Effects of elk density on birth weight of calves. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �224 Forage Class=Perennial Grasses Age=Standing Dead 30.------------------------------------------ >, (':l ?O ;:;:0.. 0 •.. U ~ -... 10 ··············... I 1 ~ ....... ··················-1·············· 1 ....• tr: '" I--___ ~ . "0 c:: .. .................. ······················ ...r Q.) N •.. c.:l -- 0 ---f--------r---- --------------4 _I_ 10 5 0 15 20 25 30 35 Elk Density (animals/km2) I Year contrast All Year. contro~ v. other. control v. 8 elk/ka2 control v. 15 elk/ke control v. 31 elk/ka linear e~~ec:ta quadratic e~~ec:t. Year 1 contro~ v. other. control v. 8 elk/ka2 control v. 15 elk/_ control v. 31 .~k/ka linear e~~ec:t. quadratic e~~ecta Dr 1 1. ]. ]. ]. 1 ]. ]. ]. ]. ]. l. 1.09.5203835 ],9.0505832 .2.352.932 2].7.9].].3339 227.7736.9::2 0.2387],09 ••63 0.8]. ]..79 9.22 9.6. 0.0], 0.07.9 0 ••039 0.2292 0.0229 0.02l.0 0.9232 66.630.25 l..9 •• 3l.7 .7. 229l.85 l.37.207396 166 ••396.3 0.05.3.6 66.630.25 1.9 ••3],7 .7.229185 l.37.207396 ],66.8396.3 0.05.3.6 3.0]. 0.09 2.].3 6.l.9 7.53 0.00 0.l.336 0.77.8 0.19.6 0.0.73 0.0336 0.962], 39.0738233 l.2.l.3.2352 5.l.82].2.3 9].•.23.5670 86 •••973.0 3.1659021 1.90 0.59 0.25 •••3 ••20 0.15 0.217. 0 .•7].7 0.6337 0.0799 0.0.63 0.70 •• ],3.783•.273 7.l.171.0. ••5079799 18.5157027 ].5••129369 0 ••899007 1 Year 3 control v. others control v. 8 elk/ka2 control v. l.5 elk/ke control. va 31 el.k/_ linear e~~ec:ta quadratic e~rec:ta 1 1 1 1 1 l. 13.7.34273 7.1171.08 •• 5079799 1•• 5157027 15 ••],29369 0 •••99007 Val.ue ::27.].2 ]. ••00 8.87 36 ••3 30.33 0.96 P>." > 3 r 1.09.5203835 19.0505832 .2.352.932 217.9],13339 227.7736.92 0.2387l.09 39.0738233 1.2.13.2352 5.1.212.3 91.23.5670 86 •••973.0 3.1659021 ]. r _an l. 1 Square ----- Contr ••• t ss Year 2 control v. other. control v. 8 elk/ka2 control v. 1.5 elk/ka control v. 31 elk/ke linear e~~ec:ta quadratiC e~~ec:ta ]. ]. 1 ...........• 2 0.0020 0.0096 0.02.7 0.0009 0.00l.5 0.36.], Figure 7. Effects of elk density on standing dead perennial grass present at the begining of the spring grazing season. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �225 Forage Class=Total o 5 10 Herbs 15 Age=Standing 20 Dead 25 30 35 Elk Density (animals/km2) IYear Contrast ll~ Year. control others control. 8 el.l</ka2 contro~ 15 e~lc/k1o 31 e1.lc/1ea control linear .-rr.ct. quadratic e~~.cta v. v. v. v. Year l. control other. 8 .~lc/lnl2 control control 15 .1lc/lclo control 31 .~k/k1o linear e~~.cta quadratic e~~ecta v. v. v. v. v. v. v. v. Year 2 control other. control 8 ellc/ka2 control 15 e~lc/k1o control 31 .~k/k1o 1inear e~~.cta quadratic e~~ecta v. v. v. v. Year 3 control. other. cantZ'ol a e~k/ka2 control 1.5 elk/lea control 31 e1k/1ea 1ine.r .~~ecta quadratic .~~ecta OF 1 1. 1. 1. 1 1 Contra.t 1 ...•.....•.. 2 ----- sa 128.8152054 26.262140. 54.0355911. 234.8669923 241.0767642 0.0932021. Mean Square 128.8152054 26.2621408 54.0355911 234.8669923 241..0767642 0.0932021. F Va~u. Pr > J! 4.88 1.00 2.05 8.90 9.14 0.00 0.0692 0.3569 0.2023 0.0245 0.0233 0.9545 1 1 1 1 1. 78.611.376 4.194883 5•• 546209 144.437949 1.71.82541.4 1..1.265.1 78.61.1.376 4.1.94.83 58.546209 144.437949 1.71.82541.4 1..1.26581 3.27 0.17 2.44 6.01. 7.1.6 0.05 0.1.204 0.6905 0.1.694 0.0496 0.036. 0 ••357 1 1. 1 1 1 1 46.970164 1.6.0.2031. 7.64274:Z 100.2548:Z4 93.378115 1.841037 46.9701.64 1.6.082031. 7.64:Z74:Z 1.00.254.:Z4 93.378115 1 ••41037 2.17 0.74 0.35 4.64 4.3:Z 0.09 0.1.909 0.4215 0;5738 0.0747 0.0.29 0.7802 1 1 1 1 1 1 15.5112791 7.9399379 5.3639:Z76 20.3703635 16.9.665:Z9 0.6793407 15. 511:Z791 7.9399379 5. 3639:Z76 :Z0.3703635 16.9a665:Z9 0.6793407 l. 31.53 16.14 10.90 41.40 34.5:Z 1.3. 3 0.0014 0.0070 0.0164 0.0007 0.0011 0.2.45 Figure 8. Effects of elk density on the standing dead biomass of herbaceous forage (annual grass + perennial grass + forbs) present at the beginning of the spring grazing season. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �226 Forage Class=Perennial Grasses Age=Standing Live 12 CI,.;! c 11 "';n 10 - >, 9 :tl ::E 8 c, 0 s.. u "'0 .~-. c 7 6 5 ············ ~ _----1r--_______ C'il -' 4 t C/) "'0 I!.l N .. C'il c;, 3 1--:.:::::.......................]'1 ••••••••••• ••••.•••••••••••. ••••••.• ---------::.::1 2 1 0 5 10 15 20 25 30 35 Elk Density (animals/km2) I Year Contrast Y.ar. control v. others eontrol. v. 8 .l.k/ka2 control va 1.5 .l.k/ka control v. 31. .l.k/ka linear e:t'r.ct. quadratie .rr.et. 1 .-.-.-.-.-.-2 Contr ••t ss X.an 1 1 1 1 1 1 10.1.8740572 4.4551.7556 3.16250164 15.43814621 13.55941251 0.1.1..75685 1.0.18740572 4.45517556 3.162501.64 15.43814621 13.55941251 0.11.75685 1 1 11..638.369 Of' SqUare F Val.u. ----- 3 Pr > f' lll. Y.ar 2.36 1.03 0.73 3.57 3.14 0.03 0.1.757 0.3493 0.4253 0.1077 0.1270 0.8738 11.6388369 4.5603544 4.4460805 16.9130156 15.289561.3 0.30521.76 3.66 1. 43 1.40 5.32 4.81 0.1.0 0.1042 0.2761 0.2816 0.0605 0.0708 0.7671 1. 1 1. 0.61690690 0.35.87224 2.453705.9 2.1.7558971 0.0001.3527 1.45132601 0.61690690 0.35887224 2.45370589 2.17558971 0.00013527 0.53 0.23 0.13 0.90 0.80 0.00 0.4931 0.6511. 0.7292 0.3794 1 1 1. 1 1. 1. 0 ••3179256 0.5401.6100 0.13.79112 1.26.9945. 0.9.560106 0.0010750. 0.831.79256 0.54016100 0.1.3.791.12 1.26.9945. 0.98560106 0.00107508 1.56 1.01 0.26 2.38 1.85 0.00 1 control va others control v. a .lk/~ control va 1.5 elk/ka control. v. 31..l.k/ka linear err.eta quadratic .rr.eta Y.ar 2 control v. other. control v. 8 .lk/~ control v. 15 .lk/ka control. v. 31..l.k/ka l..1n.ar.rr.eta quadratic .rraeta Year 3 control v. other. eontrol. v. 8 .l.k/ka2 control. v. 1.5 .l.k/ka control. v. 31. .1.k/ka linear err.eta quadratie .rraeta I. 1 1. 1 1 1. I. 4.5603544 4.4460805 1.6.9130156 15.2.95613 0.3052176 1.451.32601 0.4061 0.9946 0.2581 0.3529 0.62.0 0.1737 0.2227 0.9656 Figure 9. Effects of elk density on the biomass perennial grass present at the beginning of the season. Vertical bars give ± 1 standard error. hypotheses are shown in the table of orthogonal of live spring grazing Test of specific contrasts. �227 Forage Class=Tot al Herbs Age=Standing Live 21r-----------------------------------------~ c:?20 E 19 <, 18 ~17 - 16 ~15 ::::E14 0.13 12 e ull "0 ~10 c 9 8 7 6 5 4 3 ----- ---...... r I~~=·· I ...··=~·1[~·~=·~~.-------------i ............. . { 2~~~~~--~~~~~~--~~--~~~~--~~ 0 5 10 15 20 25 30 35 Elk Density (animals/km2) I Year COntrast DP ----- 2 1 ............ ss F Val". Pr > F 1.41 0.41 0.24 3.16 3.04 0.08 0.2801 0.5468 0.6411 0.1257 0.1320 0.7925 36.73281.05 23.0398723 9.7840209 47.8565178 37.1404557 1.2054461. 3.37 2.11. 0.90 4.39 3.41. 0.1.1 0.11.61 0.1.963 0.3801. 0.0811 0.1.1.45 0.7509 1.257891.79 1.53718415 0.09212698 3.27948980 2.1.5265073 0.55268375 1..25789179 1..53718415 0.09212698 3.27948980 2.15265073 0.55268375 0.25 0.30 0.02 0.64 0.42 0.11 0.6371 0.6028 0.8975 0.4531 0.5399 0.7532 0.06655416 5.36298994 0.00143659 2.70927976 6.78867097 3.83760183 0.06655416 5.36298994 0.00143659 2.70927976 6.78867097 3.837601.83 0.04 3.02 0.00 1.52 3.82 2.16 0.8529 0.1330 0.9782 0.2631 0.0984 0.1921 COntrast X •.•. n square All year. control. v. other. control. v. 8 .lk/~ control. v. 15 .lk/lal control. v. 31 elk/lea linear e.t:tecta quadratic .rr.eta 1 1 1 1 1. 1 15.98214635 4.62274020 2.73095877 35.87858778 34.45593751 0.8581.1.735 15.98214635 4.62274020 2.73095877 35.87858778 34.45593751. 0.85811.735 Year 1. control. v. other. control va 8 .1.k/~ control v. 15 e1.k/1ea control v. 31 e1.k/1ea linear _:t:tect. quadratic .rr.eta 1. 1. 1. 1 1. 1 36.73281.05 23.0398723 9.7840209 47.85651.78 37.1404557 1..2054461. Year 2 control. v. other. control v. 8 .1.k/~ control v. 15 elk/lea contz'ol. v. 31 elle/Iea 1in•.."..rrecta quadratic .rrecta 1. 1 1 1 1 1 Year 3 contzol. va other. control. va 8 elle/~ control. v. 15 elk/lea control va 31 .lle/Iea lin.ar erreeta quadratiC errecta 1 1 1 1 1 1 3 Figure 10. Effects of elk density on the standing live biomass of herbaceous forage (annual grass + perennial grass + forbs) present at the beginning of the spring grazing season. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �228 Forage Class=Perennial Grasses Age=Standing Live 40r-------------------------------------------~ C\l c <, ~30 ;: c -' C) :: -g 20 t 1······················f· >. 1-0 c:l E 'c ~ -' Q.) ···1 f················· 10 ~--------r-------------------------- I z 0 5 0 10 15 20 25 30 35 Elk Density {animals/km2} I Year Dr contrast A~~ 'tear. contro~ v. contro~ v. .contro~ v. contro~ other. 8 .~k/ka2 15 e~k/ka 3~ elk/ka ~ ~ quadratic .rracta 1 1 1 1 Year 1 control v. other. CODtrO~ v. 8 e~k/ka2 eontro~ 15 .1k/~ contro~ 31 .~k/ka lin.ar .'t1!.cta quadratic erreet. 1 1 1 1 1 1 'tear 2 control v. others control V. 8 e~k/ka2 control V. 15 e~k/ka contro~ v. 3~ e~k/ka ~inear erracta quadratic eireeta 1 1 1 1 1 1 'tear 3 control v. other. contro~ v. 8 e~k/ka2 contro~ 15 e~/ka contro~ V. 31 e~k/ka linear erreeta quadratic erreeta 1 1 1 1 1 1 v. ~in.ar .~t.ct. v. v. V. Contrast 1 .'.'-'-"'-' 2 ss 0 •• 61742259 0.43003319 4.79307473 9.71015692 8.~5222059 12.05896492 Xean Square 1! Va~\le 0.41742259 0.43003319 4.79307473 9.71015692 8.15222059 12.05896492 0.05 0.05 0.54 1.09 0.91 0.00 0.00 0.0013672 0.0000816 0.0013672 0.0000816 19.9414759 19.9414759 20.6763684 18.9607403 20.6763684 18.9607403 44.3297312 44.3297312 0.~8278700 0.27001437 0.16558095 0.01456.37 0.18278700 0.27001437 0.16558095 0.01456837 0.00006162 0.29060014 0.00006162 0.29060014 1.35 Pr > 0.8360 0.8336 0.4915 0.3373 0.3763 0.2894 0.9907 2.05 4.80 0.02 0.03 0.02 0.00 0.00 0.03 0.8873 0.8633 0.8927 0.9681 0.9979 0.8583 0.3627 0.3240 2.27891792 0.97 2.71071165 2.71071~65 1.16750100 1.16750100 0.94252471 0.34003452 0.94252471 0.34003452 1.39808833 1.15 0.50 0.40 0.14 0.60 3 r 0.9977 0.1922 0.1853 0.2020 0.0711 2.16 2.24 2.27891792 1.39.08.33 ----- 0.5073 0.549. 0.7167 0.4697 Figure 11. Effects of elk density on primary production of perennial grass during the spring grazlng season. Vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �229 Forage Class=Total Herbs Age=Standing live 50 ..• CIl ~40 ~ -..• 0 c:; 30 ~ -e e ?O >,- Q.. I ······················1··········· 1L.................... .I . ca"" ...S ~------- ...•v 10 Q.. "" ...•. f- ------ -t------------------I Z 0 0 5 10 15 20 25 30 35 Elk Density (animals/km2) I Year 2 ----- 3 1 ............ ss Mean square F Value Pr > 1" 1 1 1 1 1 1 0.19.639 •• ••3.782892 12.02569359 6.06798621 2.21315195 13.06577911 0.19.639 •• ••3.782892 12.02569359 6.06798621 2.21315195 13.06577911 0.01 0.15 0 ••2 0.21 0.0. 0 ••5 0.9373 0.7118 0.5.32 0.6633 0.7915 0.5268 Y.ar 1 contro~ v. others control. V. 8 el.k/ka2 control 15 el.k/kD control. V5 31 el.k/ka l.inear e~f'ecta quadratic e~~ecta 1 1 1 1 1 1 8.68.7262 5.2721022 32.9573929 0.6696918 1.0352021 .5.5193910 8.6••7262 5.2721022 32.9573929 0.6696918 1.0352021 .5.5193910 0 .•1 0.25 1.55 0.03 0.05 2.1. 0.5.67 0.6365 0.2599 0.8651 0.832. 0.1961 Year 2 control v. other. control. v. • el.k/ka2 control v. 15 el.k/ka control. 31 el.k/ka l.inear e~f'ecta quadratic e~~ecta 1 1 1 1 1 1 1.1131773 0 ••063575 16 ••6.9585 0.3605059 0.0030192 1:l.3:l36379 1.1131773 0 ••0.3575 1•••689585 0.3.05059 0.003019:l 12.3236379 0.05 0.02 0.62 0.01 0.00 0.5:l 0 ••350 0.9000 0 ••626 0.90.1 0.9913 0 ••966 1 1 1 1 1 1 22.7166972 :l7.7917863 1.2.519152. ••.2067006 2.6056826 15.972:l698 2:l.7166972 27.7917863 1.2.519152. 8.2067006 2.6056826 15.9722698 1.38 1.69 0.76 0.50 0.16 0.97 0.2.69 0.261. 0 ••170 0.5069 0.70.7 0.3630 Contrast DI" Al.l.Year. eontro~ v. others control. V5 8 el.k/ka2 control. V. 15 e1k/kD control. 31 e1k/ka 11n.ar .:t~.cta quadratic e~~ecta V. V. V. V. Year 3 control oth.1:'S control v. a .~/ka2 control. 15 el.k/ka control. v. 31 el.k/ka l.inear ef'~ecta quadratic e~f'ecta V. Contrast Figure 12. Effects of elk density on primary production of herbaceous biomass (annual grass + perennial grass + forbs) during the spring grazing season. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �230 Forage Class=Perennial Grasses Age=Standing Dead _100r---------------------------------------~ ~~ ~ 90 ~ >, 80 .a v 70 ... 0 60 I:Ul (ll t:. I:Ul !: 50 ·C c, 40 .•. ... CFl 0 !: ...-' 0 •...•............ 30 »: 20 as N := ;:::, .. .... .. .. ' 10 ' ' ••.•..•..•.••• »: 0 0 5 10 15 20 25 30 35 Elk Density (animals/km2) I Year contra.t DP v. v. v. v. All Year. contro~ other. control. 8 elk/~ control 15elk/~ control 31 elk/lea linear e1"1"ecta quadratiC .r~.c:ta v. v. v. v. Year 1 control others control. 8 elk/~ control. 15elk/1ea2 31 elk/lea eontro.l linear e1"1"ect. quadratiC e1"1"ecta v. v. o~.r. v. v. Year 2 con'C:rol control 8 elk/1ea2 15e1.k/~ contro~ control. 31 e1.k/1ea linear e~r.ct. quadratic e1"l!ecta v. v. v. v. Year 3 control other. control 8 e1.k/~ control. 1.5elk/~ control. 31.el.k/Iea linear el!l!ecta quadratic el!l!ecta 1 1 1 1 1 1 contra.t S5 7307.84260 1712.23323 2754.63154 13347.91139 13390.08478 0.77549 1 .•...•.•.... 2 Xean SqUare 7307.84260 1712.23323 2754.63154 13347.91139 13390.08478 0.77549 F Va1u. ----Pr> 3 P 31..65 7.42 11.93 57.81 57.99 0.00 0.0013 0.0345 0.0136 0.0003 0.0003 0.9557 1 1 1 1. 1 1 1772.20140 249.99284 1162.60339 2831.231.45 3096.20466 63.5.878 1772.20140 249.99284 1.1.62.60339 2831.23145 3096.20466 63.5••78 14.26 2.01 9.35 22.78 24.91 0.51 0.0092 0.2059 0.0223 0.0031 0.0025 0.5013 1 1 1. 1 1 1 3250.78443 1072.52751 595.27664 6.0 ••14667 63.9.01475 96.8.756 3250.78443 1.072.52751 595.27664 6808.14667 6389.01475 96.8.756 10.99 3.63 2.01 23.02 21..60 0.33 0.0161 0.1055 0.2058 0.0030 0.0035 0.5879 1 1 2396.37510 534.078.2 1050.45371 41.45••7817 4205.5641.5 11.52041. 2396.37510 534.07 ••2 1.050.45371. 41.45 ••7817 4205.56415 1.1.52041 1.4.55 3.24 6.3. 25.18 25.54 0.07 0.0088 0.1218 0.0449 0.0024 0.0023 0 ••002 1 1 1 1. Figure 13. Effects of elk density on elk utilization of standing dead perennial grass. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �23l Forage Class=Total Herbs Age=Slanding Dead _100 ~ ~ 90 ~ >. ~ ~ ::£ ~ :... 0 •••QIJ ::1 j 60j 1 c 50 ·c ._aCJJ. 40 1 30] C a _, :..s .--:.:: N ;:J 20 10 0 0 5 10 15 20 25 30 35 Elk Density (animals/km2) I Year Contrast All Year. control. v. other. control v. 8 elk/1<1L2 eontro~ va 15.1.k/k1II2 control. va 31 e1.k/1<II lin.ar .~~ect.a quadratic .~~ect.a Y.ar 1 control. v. other. control. v. 8 .lk/1<II2 control. v. ].5.1.k/1<II2 control. v. 3], .lk/I<II linear .~t'.ct.a quadratic e~~.ct.a v. v. Year 2 control. other. control 8 .].k/1<1L2 control v. ].551.k/1<II2 control v. 31 .lk/_ 1.inear .~~ect. quadratic e~~ect.a Y.ar 3 control v. others control 8 .1.k/1<1L2 control v. 15elk/1<1L2 3], elk/lao control linear e~~~ qua<ft.~c ~, v. v. 1 .....,...... 2 OF Contrast 5S Mean 1 6299.69136 1369.16039 2765.78365 10988.1.9107 ].1189.06440 25.84663 6299.69136 1369.16039 2765.78365 10988.19107 ]. ]. 1 1 1 1 ]. ]. ]. 1 ]. ]. ]. ]. ]. 1 1 1 ]. 1 1 ]. ]. Square ].].],89.06440 25.84663 F l1al •• e ----- Pr > 1! 20.74 4.51 9.11 36.].& 36.84 0.09 0.0039 0.0779 0.0235 0.00],0 0.0009 0.7803 1627.91193 276.89855 1034.86445 2502.09457 267]..45338 70.75377 1627.91],93 276.89855 ].034.86445 2502.09457 2671.45338 70.75377 ].0.05 ]..7]. 6.39 15.45 ],6.49 0.44 0.0193 0.23&9 0.0448 0.0077 0.0066 0.5332 2073.04&32 364.356].9 570.934.9 469&.378&], 4.64.4292], 73.47566 2073.04832 364.356].9 570.93489 4698.37 ••]. 4864.4292]. 73.47566 7.50 ]..32 2.06 ],6.99 1.7.59 0.27 0.0338 0.294& 0.200. 0.0062 0.0057 0.62.7 2662.],2372 .04.36042 ].226.&3770 396 ••~7l7' 3.].7. 0,.7. 2662.].2372 804.3&042 1226.83770 396& ••737& 18.49 5.59 8.52 27.57 26.52 0.56 0.005]. 0.0560 0.0267 0.0019 0.0021 0.4831 &0.3!r~ 3817.00979 80.3&~1.1 3 Figure 14. Effects of elk density on elk utilization of standing dead herbaceous biomass (annual grass + perennial grass + forbs). Vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �232 Forage Class=Perennial Grasses Age=Standing Live ~100r---------------------------------------------~ se ~ w 90 >, 80 ~ II) I:lD 70 1 ~ •..0 ~ I:lD .-•c.. tr: ....0 c 601 50 40 -----_ ..... ------- 30 0 :.:: 20 .--:~.: N ;:::l 10 ............... »: _---I 1 1-············ ·.·····.·.·.·.·.·.·-.· 0 0 5 10 15 20 30 25 35 Elk Density (animals/km2) I Year 1 ..._.,_..... 2 ----- DF Contraat S8 X.an Squa",. F Va~u. Pr > F A.U Year. control v. other. control V& 8 .l.k/1aI2 contro~ v. 15elk/Jca2 contro.l V& 31 elk/_ linear .~r.ct. quadratic e~~ecta 1 1 1 1 1 1 2151.386070 501.592860 1677.844067 2525.766.71 2593.558235 357.835612 2151.386070 501.592860 1677.844067 2525.766871 2593.558235 357.835612 6.23 1.45 4.86 7.32 7.51 1.04 0.0467 0.2734 0.0696 0.0353 0.0337 0.3478 Year 1 control V& other. control vs 8 elk/1aI2 control. vs 15el.k/_2 cont.%'ol V& 31 .1k/_ linear e~~ect& quadratiC e~~ecta 1 1 1 1 1 1 703.303989 169.003609 627.390022 724.270722 744.309184 180.283581 703.303989 169.003609 627.390022 724.270722 744.309184 180.283581 5.05 1.21 4.51 5.20 5.35 1.29 0.0657 0.3128 0.0780 0.0627 0.0601 0.2986 Year 2 control vs others control vs 8 .1k/1aI2 contro.l v. 15elk/Jca2 control V& 31 el.k/_ linear e~~ecta quadratiC .~~ecta 1 1 1 1 1 1 675.906321 113.824158 706.497634 698.727628 772.063497 196.954482 675.906321 113.824158 706.497634 698.727628 772.063497 196.954482 1.79 0.30 1.87 1.85 2.04 0.52 0.2299 0.6032 0.2208 0.2231 0.2031 0.4978 Year 3 control V& oth.ra control. 8 el.k/Jca2 control. v. 15elk/1aI2 control V& 31 .lk/_ l.1n ••",.~~ecta quadratic .~~ecta 1 1 1 1 1 1 773.93561 228.68989 373.24742 1135.82189 1098.26436 28.12600 773.93561 228.68989 373.24742 1135.82189 1098.26436 8.92 2.64 4.30 13.10 12.66 0.0244 0.1555 0.0834 0.0111 0.0119 contraat v. 28.1.2600 0.32 3 0.5897 Figure 15. Effects of elk density on elk utilization of live'perennial grass available at the beginning of the spring grazing season. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �233 Forage Class=Perennial -~ ~ Grasses Age=Standing Live 90 w 80 •.... ,.:::l QD 70j ell 1.0 60, ~ 0 ::- ell ~ 0 ... ::: .-~ .--..;::l E- 0 50 40 30 _-----1 t------------r------- ~r----rI-------------------------------------------:-I 0 ell 20 N 10 0 wo:'•• __ .•• _-_ ••• __ .•..•_..... o • ••••••• 5 -_ .•.•. 10 15 20 25 30 35 Elk Density (animals/km2) I Year contrast DF Contrast 1 ------------2 ----- ss All Year. control. v. other. contro~ v. 8 .lle/~ control v. 15 .lle/Iao control v. 31 .lle/Iao lin.ar err.cta quAdratic .~r.cta 1 1 1 1 1 1 Year 1 oontrol. v. other. control. v. 8 elle/~ control va 15 elle/Iao control v. 31 elle/Iao lin.ar errecta quadratiC erreeta 1 1 1 1 1 1 83.269562 13 ••1773. 113.202014 63.924133 72.920421 46.76 •• 44 Year 2 control v. others control. va .lle/~ contro1 v. 15 .lle/Iao control v. 31 .lle/Iao linear erreot. quadratic errect. 1 1 1 1 1 1 1 1 1 1 1 1 • Year 3 cont.rol control control control lin.ar v. v. v. v. .rr.ct. quadratic other. 8 elle/~ 15 .lle/Iao 31 elle/Iea errecta 498.8454173 118.4665741 412.7378664 552.6633931 567.1075782 101.764.429 Mean Square 498.8454173 118.4665741 ,012.7378664 552.6633931 567.1075782 101.764.429 F tJalu. 3 Pr > F 6.48 1.54 5.36 7.18 7.36 1.32 0.0438 0.2612 0.0599 0.0366 0.0349 0.2941 83.269562 13.81773. 113.202014 63.924133 72.920421 46.76 ••• 4 2.41 0.40 3.28 1..5 2.11 1.35 0.1716 0.5505 0.1203 0.2227 0.1966 0.2 •• 9 56.875.031 9.7590.2. 64.39611.3 53.6460500 59.564.610 20 ••539205 56 ••754031 9.7590.2. 6 •• 3961183 53.6460500 59.5648610 20.8539205 2.12 0.36 2.40 2.00 2.22 0.78 0.1959 0.56.7 0.1725 0.2073 0.1.70 0.4122 ...4••05395 14 •• 26107a 273.039161 6.5.100172 624.496136 36.812425 4.4.805395 1.4.26107. 273.039161 645.100172 62 •• 496136 36 ••12425 a.66 2.5. 4.a. 11.52 11.15 0.66 0.0259 0.1596 0.0693 0.01.6 0.0156 0 ••••• Figure 17. Effects of elk density on elk utilization of live perennial grass.produced during the spring grazing s~a~on. vertical bars g1ve ± 1 standard error. Test of spec1flc hypotheses are shown in the table of orthogonal contrasts. �234 ;< 100 ~ Forage Class=Total I Herbs Age=Standing 15 20 Live 90 80 1 ~ ~ 701 ~ 0 '"' 60 ""Qll 50 = .i: e, en 40 ••... 0 30 = 0 :.:; 20 ~ ._- .. IS ~ 10 0 5 0 10 25 30 35 Elk Density (animals/km2) I Year 1 ................. 2 contrast ss X.an Square 1 1 1 1 1 1 10.9.039735 5••4919.4 101.2.415967 1711.323529 2075.77325. 79.620253 10.9.039735 5••491.9.4 1012.415967 1711..323529 2075.77325. 79.620253 Year 1 control. va others control. 8 e~k/1ca2 control. v. 15elk/_2 control. v. 31 .lk/_ lin.ar .rrecta quadratic .rr.eta 1 1 1 1 1 1 400.59.720 234.583704 133.54.602 490.799560 3••••998.3 23.951714 •••• ar 2 control v. other. control v. 8 .~k/1ca2 control v. 1.5.1k/_2 v. 31 .~k/_ control l.in.ar .rrecta quadratic .rr.eta 1 1 1 1 1 1 Year 3 control. v. other. control v. 8 e~k/1ca2 contro.l v. 15e~k/1ca2 control. 31 .~k/lca l.inear .rrecta quadratiC .rrecta 1 1 1 1 1 1 contraat DF year. contro~ v. other. elk/_2 contro~ v. contro~ v. 15.1k/_2 contro.1 31 .~k/Ica lin.ar .rrect. quadratic errecta ----- P Va~\l. Pr > P 2.73 0.15 2.54 4.30 5.21. 0.20 0.1493 0.7147 0.1619 0.0.35 0.0625 0.6705 400.59.720 234.5.3704 133.548602 490.799560 388.899.83 23.951714 2.44 1.43 0.81 2.99 2.37 0.15 0.1692 0.2770 0.4018' 0.1345 0.1746 0.7156 623.965817 122.45351.6 640.284454 61.5 ••75737 663.172472 195.236549 623.965.1.7 122.45351.6 640.284454 61.5.875737 663.172472 195.236549 1..07 0.21 1.09 1.05 1.13 0.33 0.3415 0.6634 0.335. 0.3444 0.3279 0.5.45 147.973.3 172.5351.5 333.10142 609.14638 1118.27967 11.63926 147.97383 172.53515 333.10142 609.14638 1118.27967 11.63926 0.73 0 ••5 1.64 3.00 5.50 0.06 0.4264 0.3925 0.2478 0.1342 0.0574 0.81.9 3 A~~ v. • v. v. Figure 16. Effects of elk density on elk utilization of herbaceous biomass (annual grass + perennial grass + forbs) available at the beginning of the spring grazing season. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �235 Forage Class=Total ~ ~ c.J E v ~ ~ 0 Herbs Age=Standing live 100 90 j 80j 70j 60.j ----' 5°1 ~ 0 E- ... ._:: 40 .-'~_N 20 0 30 0 -' ;::l k----------- ..1-~- ..----. .",.. 5 0 1 .....-::::-~;t--.---.--..-.-----..--.--.-.-.-__._. .•T ._..~==.t1;:: 1 10 0 ______ J 10 15 25 20 ~I 30 35 Elk Density (animals/km2) IYear Cofttraat COntrast '---'---'--- 2 P Value ----- 3 Pr > r 58 Mean SqUare 1 1 1 1 1 1 l86.5201431 8.6198144 312.5201998 350.1005845 542.5730463 16.9503603 186.5201431 8.6198144 312.5201998 350.1005845 542.5730463 16.9503603 1.74 0.08 2.91 3.26 5.06 0.16 0.2355 0.7864 0.1388 0.1209 0.0656 0.7048 Year 1 control. v. other. control v. 8 el.k/1aL2 control vs 15 e1k/lal control v. 31 e11</1al linear errecta quadratic .rrecta 1 1 1 1 1 1 46.7139613 23.4546333 33.2353891 37.6218458 30.8083009 15.7492966 46.7139613 23.4546333 33.2353891 37.6218458 30.8083009 15.7492966 1.74 0.87 1.24 1.40 1.15 0.59 0.2356 0.3864 0.3088 0.2816 0.3256 0.4731 Year 2 control va other. control vs 8 ell</1aL2 control va 15 el.l</1ao control.. vs 31 elle/Iao lin •• r .~r.ct.a quadratic errect. 1 1 1 1 1 1 75.1692342 13.9617614 97.7165007 57.9945235 64.5393735 40.6552085 75.1692342 13.9617614 97.7165007 57.9945235 64.5393735 40.6552085 1.25 0.23 1.63 0.96 1.07 0.68 0.3063 0.6470 0.2495 0.3640 0.3401 0.4424 Year 3 control v. other. eontrol v. 8 el.lc/1aL2 eontrol vs 15 elk/lao control vs 31 elk/lao lin.ar errecta quadratic errecta 1 1 1 1 1 1 66.426561 186.725680 224.083877 348.168760 716.142489 10.327788 66.426561 186.725680 224.083877 348.168760 716.142489 10.327788 0.40 1.12 1.34 2.09 4.29 0.06 0.5513 0.3307 0.::1905 0.1986 0.0836 0.8l18 All Year. control vs others control va 8 el.k/1ao2 control vs 15 el.k/Iao control.. vs 31 elk/lao linear e~~.et. quadratic erreeta Df' 1 Figure 18. Effects of elk density on elk utilization of herbaceous biomass (annual grass + perennial grass + forbs) produced during the spring grazing season. vertical bars give + 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �236 Forage Class=Perennial Grasses Age=Standing Dead 100.r---------------------------------------~ 901 1 801 70j c c 60 _---: - ...••-......•.... .",.;~;~ 00 .... 30 .. ---- .".... »> .... ",. ---. .>" ',,,/' 20 10 o 5 10 15 25 20 30 35 Elk Density (animals/km2) I Year contrast OF Al.l Year. control. v. o~.rs contro~ v. 8 eUc/k112 control va 15 .lk/Iao control. v. 31 elk/lao linear err_eta quadratic ettects Y.er 1 control v. others control v. 8 .lk/k112 control. v. 15 elk/lao control. va 3],elk/lao linear .~r.ct. quadratic .tt.eta v. v. v. v. Year 2 control other. contro.l a .lk/1ao2 control 15 .lk/Iao contro.l 31 .1k/1ao lin.ar .tt.cta quadratic .tt.cta v. Y.er 3 con1:.rol. others control. va 8 .lk/k112 control. v. 15 .lk/Iao control v. 31 .lle/Iao lin.ar err.eta quadratic ett.eta ]. ]. ]. 1 1 ]. ]. ]. 1 ]. ]. 1 1 ]. 1 1 1 1 ]. 1 1 1 ]. 1 Contra.t SS 3209.554674 ].].54.937],45 8].9.878149 5799.263352 5351.615983 3.225230 1 ...•.••..... 2 ----- Mean SqUare 3209.554674 ],154.937145 8].9.878149 5799.263352 5351.615983 3.225230 F Value Pr > 3 F 7.74 2.79 1.98 ].3.99 12.91 0.01 0.03],9 0.1462 0.2093 0.0096 0.0115 0.9326 8.73 1.37 3.02 1••74 19.77 0.12 0.0255 0.2.69 0.1329 0.0049 0.0043 0.73.6 762.77615 119.35737 264.06424 1638.29524 1727.6473. 10.6.],29 762.776],5 ],],9.35737 264.06424 1638.29524 1727.6473. 10.68].29 849.48449 444.38825 115.36251 1565.89674 ].317.1196. 9.89976 849.4.449 444.38.25 115.36251 1565 ••9674 1317.1196. 9 ••9976 2.23 1.17 0.30 4.12 3.46 0.03 0.1.57 0.3213 0.6017 0.08 •• 0.1121 0.8771 1710.76843 721.3011. 510.93875 2688.77607 2386.38163 10.91665 1710.76.43 721.30118 5],0.93875 2688.77607 2386.38163 10.91.665 5.03 2.1.2 1..50 7.91. 7.02 0.03 0.1955 0.2661 0.0307 0.0380 0.8637 0.0660 Figure 19. Effects of elk density on total utilization (use by elk + cattle) of standing dead perennial grass. Vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �237 Forage Class=Total Herbs Age=Standing Dead 100 1 90 1 ~ 801 1, 704 ._::c 60] -' <'0 ._ -...• N -_. 50 I 40 ~ c 30 E- 20 10 0 0 5 10 DF Contrast 20 5S Xean square F Va~u. 30 25 Elk Density (animals/km2) 1 ._.__.._-_.-2 ----- IYear Contra.t 15 35 3 Pr > P All Years control v. other. contro.! va 8 elle/ka2 control va 15 elle/lea control va 31 elle/lea ~in.ar e~1!.ct. quadratic .~~.cta 1 1 1 1 1 1 2022 ••31634 707.970840 4•••124365 3778.161235 3507.023206 7.577182 2022 ••31634 707.970840 4•••124365 3778.161235 3507.023206 7.577182 3.64 1.27 0.8. 6.80 6.31 0.01 0.1051 0.3022 0.3.49 0.0403 0.0458 0.9109 ~•.• r 1 control v. other. control va 8 .11e/lea2 control va 15 .lle/lea control va 31 elle/lea linear .~1!.cta quadratic e~~ecta 1 1 1 1 1 1 557.23873 112.26394 125.60198 1297.42052 1316.74219 29.9955. 557.23.73 112.26394 125.60198 1297.42052 1316.74219 29.99558 4.87 0.98 1.10 11.34 11.51 0.26 0.0694 0.3601 0.3351 0.0151 0.0146 0.6269 Vear 2 va others control control "a 8 elle/ka2 control va 15 .lle/Jew control va 31 elle/Jew line.., e~~ecta quadratic e~~ecta 1 1 1 1 1 1 235.851221 103.293322 24.942.69 504.464916 445.773523 13.0454.4 235.851221 103.293322 24.942.69 504.464916 445.773523 13.0454.4 0.52 0.23 0.06 1.11 0.9. 0.03 0.4975 0.649. 0.8222 0.3318 0.3593 0.870. Y.ar 3 control va other. control va 8 elle/ka2 control "a 15 elle/lea control va 31 elle/lea line.., .~~ecta quadratic e~~ecta 1 1 1 1 1 1 1516.10493 641.46327 4.6.89139 2302.41740 2040.50720 1••67030 1516.10493 641.46327 486.89139 2302.41740 2040.50720 18.67030 5.24 2.22 1.68 7.97 7.06 0.06 0.0619 0.1869 0.2420 0.0303 0.0377 0.8079 Figure 20. Effects of elk density on total utilization (use by elk + cattle) of standing dead herbaceous biomass (annual grass + perennial grass + forbs). Vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �238 Forage Class=Perennial Grasses Age=Standing Live 100.r---------------------------------------~ 901I 80i ............····t··· 70 ::: :I H 60] 1-······· I1-- 50 .-_. 4°1 30 1 z: i " , ······1 I ------tt-------------------i _----- :0 o Eo- 20 10] O~~~~~ o __ ~ __ ~~~~~--~~~~~~~ 5 10 15 20 25 30 35 Elk Density {animals/km2} I Year Contrast OF AU. Year. vs others control contro.l vs II e1.k/1aa2 vs 15 elkin control vs 31 elkin control linear errecta quadratic effects contrast 1 ............ 2 ----- 55 X•••• SqUare F value 1 1.51. •.•• 39905 1.5•• 6.90.26 36.4231.93.• 132.6110063 73 ••20295 .• 21.921111,,77 control vs others control. vs II elk/n2 control vs 15 elk/Ial vs 31 elk/_ control linear effects quadratiC effects 1. 1 1 1. 1. 1. 1.••3 .• 1.372 0 •.• 92.005 1..3675.31 1.••32 .• 6 .• 62 13.5"11.723 ••.•2591.51. 1.113,,1.372 0.492.005 1..3675.31 1. .••32 .• 6 .• 62 13.5"11.723 ••.•2591.51. 0.02 0.01 0.02 0.1.7 0.1.6 0.1.0 Y.ar 2 control v. other. control va II elk/1aa2 contro.l va 15 elk/_ control vs 31 elkin linear effec:t.a quadratic effects 1. 1. 1 1. 1. 1. 1.7•• 1100.7. 1.9".3"1.299 63.2 .••.• 35 117.9"3573 5•• 2.1.61.3 55.01.32711 1.7 •• 1100.711 194.341.299 63.2 .••.• 35 1.17.9"3573 5•• 2.1.61.3 55.01.32711 11..25 12.23 3.9. 7."2 3.67 3.46 Year 3 control vs otb.r. elk/1aa2 control. vs v. 15 elkin control control v. 31. elkin linear effects quadratiC .rrecta 1. 1. 1. 1. 1. 1. .• 3."5355.9 51 •.• 99755 .• 1.3.4671.21.5 2.·.09.2.• 25 1.2.7269796 12.9:JS0962 .• 3 •.• 5355.9 51.•.• 99755 .• 1.3."671.21.5 2••09.2"25 1.2.7269796 12.9350962 Year 1. 1. 1 1 1. 1.51•.•• 39905 1.5 •• 6.90.26 36 •.• 231.93.• 132.6110063 73.11202954 21..9211."77 3 Pr > P 1..24 1..30 0.30 1.09 0.61 0.1.11 0.307. 0.2975 0.60"5 0.3373 0."662 0.6.6 .• 0.11••0 0.941.. 0.9032 0.6957 0.7036 0.7636 .1 • 0.63 0.75 0.20 0."1. 0.1.11 0.19 0.0153 0.0129 0.0931 0.03"5 0.1.0"0 0.1.1.22 0 •.• 57 .• 0."205 0.6739 0.5"67 0.6.24 0.6.00 Figure 21. Effects of elk density on total utilization (use by elk + cattle) of live perennial grass. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �239 Forage 100] Class= Total Herbs Age=Standing Live 90 j 80 ..•._~c N so I __ j 1 501 ------j--------------.- .. -I.... -----.- ..--... -..... ----... -.- ···--·---·1 ------.-------- r: T. 40 r . I 1 1'..... -" 1-- <; L /,// 30 _ -------------- '( 20 10 o 5 10 15 20 25 30 35 Elk Density (animals/km2) I Year OF COntrast Years eontrol v. other. eontrol v. 8 e~k/D4 eontrol v. 15 elk/1cwI control. vs 31. e~k/Ial 11n •• r err.ct. quadratic .rrecta Contraat ss 1 X.an .---------.- 2 ----- 3 Pr > F Square F value 3.1705653 35.8760060 106.2739624 0.001.7904 11.733~752 44.1.432630 3.1705653 35.&760060 106.2739624 0.001.7904 11.7331.752 44.1.432630 0.01 0.10 0.30 0.00 0.03 0.13 0.9275 0.7605 0.602& 0.99&3 0.8612 0.7355 1 1 1 1 1 1 29.8476507 6.3093769 33.7684775 25.5973844 27.4187952 12.6736876 29.&476507 6.3093769 33.7684775 25.5973844 27.41&7952 12.6736.76 0.56 0.12 0.63 0.48 0.51 0.24 0.4838 0.7433 0.4576 0.51.54 0.5014 0.6441 1 1 1 1 1 1 155.064081 102.070530 159.507443 60.366419 38.996241 136.714032 155.064081 102.070530 159.507443 60.366419 38.996241 136.714032 1.09 0.72 1.13 0.43 0.2& 0.97 0.3357 0.4285 0.3294 0.5380 0.61&6 0.3638 1 1 1 1 1 1 219.978420 528.504963 0.342350 162.707372 30.781127 14.022595 219.97&420 528.504963 0.342350 162.707372 30.781127 14.022595 0.36 0.&7 0.00 0.27 0.05 0.02 0.5698 0.3875 0.9819 0.6237 0.8296 0.8844 1t.~~ Year 1 control control control control I1n.ar v. other. v. 8 elk/D4 v. v. .rr.ct. quadr.tic 15 31 e~lc/1cwI e~lc/Ial err.ee. Y •• r 2 control. other. eontrol v. 8 e~lc/D4 control 15 e~k/Ial eontrol v. 31. e~k/Ial line.,...rrecta quadratic errecta v. v. v. v. v. v. Year 3 control others control 8 e~k/D4 contro.l 15 e~k/Ial control. 31 e~k/Ial lin •• r .:rt'ect. errecta quadratic 1 ~ 1. 1. 1 1. Figure 22. Effects of elk density on total utilization (use by elk + cattle) of live herbaceous biomass (annual grass + perennial grass + forbs). vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �240 Forage Class=Perennial --' co 50 0 E- 40 ... 0 I1.l 30 t:lJl -' 20 L I1.l Co) l.o I1.l 10 0.. 0 Age=Standing Live ----I co = Grasses ........ . ........ I .... --- .•_-- ..••..._-- ...-_ ... _ 0 + ~ ~~ ~~ ~~~r-------------- 1-_ ...•- .........•••.•....•...----1---------------------------------------------1" 5 10 15 20 30 25 35 Elk Density (animals/km2) I Year Contra.t OJ! v. v. v. v. All Years others control 8"ellc/ka2 eontrol. 15 ellc/a control control. 31 ellc/a linear el!"l!"ect. quadratie el!"l!"ecta v. v. • v. v. Year 1 control other. elk/ka2 control control 15 ellc/a contro~ 31 ellc/a linear el!"l!"eeta quadratie el!"reeta v. v. • v. v. Year 2 control other. elk/ka2 eontrol control. 15 elk/a control. 31 ellc/a lJ.n•• r .l!"reeta quadratie .l!"l!"eeta v. v. v. v. • Y.ar 3 control. oth.Z'. .11c/ka2 eontrol control 15 .llc/a eontrol 31 .llc/a linear .l!"recta quadratie .l!"l!"ecta COntraat 1 ------------2 ----ss M.an Square 7! Val •• e Pr> 3 P 1 1 1 1 1 1 49._.45 •• 173 11•• 4665741 412_737.66 •• 552.6633931 567.10757.2 1.01_76".429 49•••••5•• 173 11 •• 4665741 "1.2.737.66" 552.6633931 567.10757.2 101..76••••• 29 6.4. 1.54 5_36 7.1. 7.36 1.32 0.0 •• 3. 0.261.2 0.0599 0.0366 0.03"9 0.2941. 1 1 1 1 1 1 .3.269562 13 ••1773. 11.3.20201" 63.9241.33 72.920"21. 46.76."44 .3.269562 13 ••1773. 113.202014 63.924133 72.920421 46.76."44 2.41 0.40 3.2. 1 ••5 2.11 1.35 0.1716 0.5505 0.1203 0.2227 0.1966 0.2 ••9 1 1 1 1 1 1 56 ••75 •• 031 9.7590.2. 6••• 39611.3 53.6"60500 59.56".610 20_.539205 56 ••754031 9.7590.2. 6••• 39611.3 53.6"60500 59.56".610 20 ••539205 2.12 0.36 2.40 2.00 2.22 0.7. 0.1959 0.56.7 0.1725 0.2073 0.1.70 0.4122 1 1 1 1 1 1 ••••••• 05395 14"_261.07. 273.039161 6"5.100172 62".4961.36 36_.12425 4•••••05395 14 ••• 26107. 273.039161 645.100172 62 ••••• 96136 36 ••12425 ••66 2.5. 4.a. 11.52 11.15 0.66 0.0259 0.1596 0.0693 0.0146 0.0156 0 •••••••• Figure 23. Effects of elk density on the proportion of total utilization (use by elk + cattle) of live perennial grass that resulted from elk grazing. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �241 Forage Class=Perennial Grasses Age=Standing Live 100 1 1 ~ --'-' ".) 90J I 801 I j :: 601 u >. 50 C -'~ 401 :-l 30 :::l 20 .--' ·········-1 .s->: _._._•••.•••.• - •...•.•..•.•.. , .•••.. :••••••••••••.•••••••.••••• - I ...::l C I·· 70i }-r---__ f---___ + __ r --- -- -_ -I .•..•.--s-. _ ---------------1 10 0 0 5 10 15 20 25 30 35 Elk Density (animals/km2) I Year Contrast Year. control v. other. control va 8 .~k/ka2 contro~ va 1.5 e~k/kJI contro~ va 31. e1.k/kJI ~in.ar .:r~.ct. quadratic el!'l!'ects Year 1 control va other. contro.! va 8 .1.k/ka2 control v. 1.5 e1.k/kJI control v. 31. e1.k/1al linear err.eta quadratic .l!'l!'ecta A~~ Year 2 control va other. control v. 8 .1.k/ka2 control va 15 e~k/kJI control v. 31 .1.k/kJI 1.in.ar el!'l!'ecta quadratic .l!'l!'ecta Year 3 control v. other. control va 8 .1.k/1aL2 control va 1.5 .1.k/kJI eontro.l v. 3~ .~k/kJI lin •• r .~t'ecta quadratiC el!'l!'ecta 1 ...•........ 2 Contraat ss lI.an Squar. 1. 1. 1. 1. 1. ~00.5,,00~38 2.93"1.990 203.9"09045 1.43.8346569 231..71.37538 29.21."36,,9 ~00.5,,001.38 2.93"1.990 203.9409045 1.43.83"6569 231..7137538 29.21..3649 1. 1. 1. 1. 1. 1. 60.3.7081. 9.091.578 1.39.45.384 1.7.72.020 23.61..860 94 ••9659. 1. 1. 1. ~ OF ~ ~ ~ ~ 1. 1. 1 1 1 l! Va~u. ----- 3 Pr > F 2.05 0.06 4.~5 2.93 4.72 0.59 0.2025 0.81.51. 0.0877 0.1.379 0.0729 0 ••699 60.387081 9.091578 1.39••5"3.4 1.7.72.020 23.61.••60 94 ••96598 0.99 0.~5 2.28 0.29 0.39 1..55 0.3587 0.71.31. 0.1.81.. 0.6097 0.5572 0.2593 33.989673 1.1.7.00060. 0.005160 ~2.S021.40 0.0069.7 •• 1.25261. 33.989673 1.1.7.000604 0.0051.60 1.2.5021..0 0.006987 8.125261. 1.••• 5.10 0.00 0.5" 0.00 0.35 0.2693 0.0647 0.9.85 0.4 •• 3 0.9.66 0.5735 237.972752 23.372780 1.65.22••• 9 403.93~401. .5•• 92056. 6.~0477. 237.972752 23.3727.0 165.228 •• 9 403.931.01. 45•. 920568 6.~04778 1.2.53 ~.23 •. 70 2~.27 206.~7 0.32 0.01.22 0.3097 0.0256 0.0036 0.0027 0.5913 .0 Figure 24. Effects of elk density on cattle utilization of live Test of perennial grass. Vertical bars give ± 1 standard error. specific hypotheses are shown in the table of orthogonal contrasts. �242 Forage Class=Tot al Herbs Age=Standing Live 100 90j ,0 '" --'-' 1) :tl u >. ..c ::: 80J , J 70 1 ]._ _ ::1 _+._ -+ __ _.. r 1 c ~ 40j := .--.-' N 30 - 20 -, 10 0 5 0 10 15 20 25 Elk Density (animals/km2) I Year 1 -----------2 ----- DP Contraat ss X.an Al.l. Year. contro~ va other. contro~ va 8 .l.lc/1cJI2 eontro1 va 15 .l.lc/1aI control. va 31 el.lc/1aI linear .~rec:t. quadratic .rr.eta 1 1 1 1 1 1 141_0543311 9.3251216 54.3067964 348.5189300 394.7304766 6.3855174 141.0543311 9.3251216 54.3067964 348.5189300 394.7304766 6.3855174 Year 1 control. va other. contro.l va 8 .l.lc/1aI2 control. va 15 .l.lc/1aI control va 31 .l.lc/1aI l.in.ar e~r.cta quadratic .~~ecta 1 1 1 1 1 1 1.88090498 5.43426527 0.00212068 1.15407577 0.09.73838 0.166.9353 y•.•. r 2 control. va other. control. va 8 .l.lc/1cJI2 control va 15 el.lc/1aI control "a 31 .l.lc/1aI 1. inear e~~ecta quadratic .~~ecta 1 1 1 1 1 1 14.3069554 40.5317115 Y.ar 3 control. va other. control va 8 el.lc/1ca2 control va 15 el.lc/1aI eontro.l va 31 el.lc/1aI 1. inear e~recta quadratic e~recta 1 1 1 1 1 1 Contrast Square P Val.". 35 3 Pr > F 0.65 0.04 0.25 1.60 1.81 0.03 0.4520 0.8430 0.6356 0.2531 0.2271 0.8698 1.88090498 5.43426527 0.00212068 1.1.5407577 0.09873838 0.16689353 0.04 0.10 0.00 0.02 0.00 0.00 0.8572 0.7603 0.9952 0.8878 0.9671 0.9572 0.0237682 3.2003173 28.263405. 14.3069554 40.5317115 7.5320602 0.0237682 3.2003173 28.2634058 0.1.7 0.48 0.09 0.00 0.04 0.33 0.695. 0.5156 0.7760 0.9872 0.8525 0.5851 528.16859 .6.94584 241.94365 9.6.89976 1043.86585 0.2.195 528.16859 86.945'4 241.94365 986.89976 1043.86585 0.28195 1.36 0.22 0.62 2.54 2.69 0.00 0.2880 0.6530 0.4602 0.1622 0.1524 0.9794 7.5320602 30 Figure 25. Effects of elk density on cattle utilization of live herbaceous biomass (annual grass + perennial grass + forbs). Vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �243 Forage Class=Perennial Grasses Age=Slanding Live 2 0.40r-----------------------------------------~ ;:::-0.38 '-0.36 ~ 0.34 -'::0.32 ~0.30 ~ 0.28 ::; 0.26 2'30.24 3°·22 _ 0.20 ~ 0.18 E 0.16 ~ I v 0.14 0::0.12 ~0.10 ~ 0.08 ~0.06 ...~ :r... ••. .s-> i- I .•..•.. ......••..••....••.••.......•.....••.....•..••...••.....•••••..... I ............ t ...... _ -------~-------- J ---------1 0.04~~--~----~~--~----~----~--~~----~ o 5 10 15 20 25 30 35 Elk Density (animals/km2) I Year Contra.t Of' --- Contraat S5 1 Kean .•••_._._...2 ----- P Value Pr > Square 3 r All Year. eontrol vs other. control vs 8 elk/Jca2 control va 15 elk/klo control vs 31 elk/klo l1n.ar err.ct. quadratic et't'ecta 1 1 1 1 1. 1 2.98963061 0.05.87150 1.58210222 7.47941064 9.031.41804 0.09059563 2.98963061 0.05887150 1.58210222 7.47941064 9.03141804 0.09059563 1.36 0.03 0.72 3.41 4.1.2 0.04 0.2.71 0.8752 0.4281. 0.1142 0.0887 0.8456 Y.ar 1 control vs others control v. 8 elk/klo2 control vs 1.5elk/klo control. v. 31 elk/klo linear .rrect. quadratic .rrecta 1 1 1 1. 1 1 5.8454912 1.5789892 1.2553817 12.5686217 12.2287822 0.1.812986 5.8454912 1.5789892 1.2553817 1.2.568621.7 1.2.2287822 0.1812986 1.75 0.47 0.38 3.76 3.66 0.05 0.2343 0.51.77 0.5626 0.1006 0.1.044 0.8236 2 control v. other. control. v. 8 elk/Jca2 control v. 1.5e1.k/klo control vs 31 elk/klo lin •• r ert'ecta quadratic errecta 1 1 1 1 1 1 0.87246429 3.1.4115391 0.01610665 0.1.511.0586 0.04087717 0.49295989 0 ••7246429 3.1.41.1.5391 0.01610665 0.1.511.0586 0.04087717 0.49295989 0.1.8 0.66 0.00 0.03 0.01 0.10 0.6832 0.4471 0.9555 0.8643 0.9291 0.7582 1 1 1 1 1 1. 2.2.349490 0 ••761090. 1.40440466 2.49766183 2.26823336 0.36792826 2.28349490 0.87610908 1.40440466 2.497661.83 2.26823336 0.36792826 7.64 2.93 4.70 8.36 7.59 1.23 0.0326 0.1.376 0.0732 0.0276 0.0330 0.3096 Y.ar v. v. v. Y.ar 3 control other. control v. 8 elk/Jca2 control 1.5elk/kII control 31..1k/kII lin •• r err.eta quadratic .rrecta Figure 26. Effects of elk density on removal (intake + trampling) of live perennial grass by cattle. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �244 Forage Class=Total Herbs Age=Standing Live 0.6 '0 <, ,.. 0,5 - 0.4 N :: <, ~ ~ ....• ....• :'0 u .••••..••...••.....•••..•.......•.....••.........•.••.......•.............•......... 0.3 >-. ,.Q <:Il .•....•... 0.2 > 0 6 Q.) 0.1 .................... t ' ~-------------- J ----------1 c:: Q.) bD 0: ••0 0.0 ~ -0.1 0 5 10 15 20 25 30 35 Elk Density (animals/km2) I Year Contra.t OF Years control VII others contro~ VII e~k/1aa2 control VII ~5 .~k/lQI control VII 3~ e~k/n linear e-rteeta quadratic e~~ect. A~~ " ~ Y.ar control va others control V. 8 elk/lcJo2 control V. ~5 elkin control V. 31 •• ~k/n linear ettect. quadratic e~~ecta Year 2 control V. others control V. elk/n;ol control V. ~5 elkin control V. 31 elkin ~inear e~~ect. quadratic e~~ecta • Y.ar 3 control V. other. control. v. 8 elk/lcJo2 control. v. ~5 elk/n control v. 31 elk/n ~inear .~~ecta quadratiC e~~ecta ~ ~ ~ ~ ~ ~ Contrast --- ss 1.2oo2479~ 2.~7722749 1 .•.......... 2 ----- Mean Square P Value 3 Pr > P 8.55739~96 5."~979833 6.55285327 ~.2002479~ 2.~7722749 2.94907263 ".55739~96 5.8~979833 6.55285327 O.~O 0.~9 0.25 0.74 0.50 0.56 0.7589 0.6804 0.6325 0.4240 0.5059 O.48~3 0.55967568 0.06866966 6.84439401 0.27209880 0.023.5962 6.56847783 0.55967568 0.06866966 6.84439401 0.27209880 0.02385962 6.56847783 0.07 O.O~ 0.85 0.03 0.00 0.81 0.8013 0.9296 0.3930 0.8605 0.9584 0.4021 ~ 2.~399662 0.7603231 9.85~0021 0.1826105 0.1577694 12.266.994 2.~399662 0.760323~ 9.85~0021 0.1826105 0.1577694 ~2.2668994 0.18 0.06 0.84 0.02 0.01 1.04 0.6843 0.8076 0.3950 0.904. 0.9~15 0.3461 1 1 1 1 1 1 ~6•••oo9.0 ~0.0212246 7.730527;01 16.9563705 ~3.15350.~ 2.661.578 ~6.88oo980 ~0.02~2246 7.7305272 ~6.9563705 13.1535081 2.84 ~.69 ~.30 2 ••6 2.;012 0.45 0.1427 0.24~5 0.2973 0.~420 0.~.72 0.5;01110 ~ ~ ~ ~ ~ 1 1 ~ ~ 1 1 2.94907263 2.6618578 Figure 2~. Effects of elk density on removal (intake + trampling) of herbaceous biomass (annual grass + perennial grass + forbs) by cattle. Vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �245 Forage Class=Perennial _ Grasses Age=Standing Dead 0.16 0.15 'N :: 0.14 0.13 <, 0.12 ~ 0.11 ..:: 0.10 0.·09 0.08 £ .----- ·······_ ..· 1· g:g~ <, • 0.05 i 0.04 ~ 0.03 0:: 0.02 ~ 0.01 ~ 0.00 ~ -0.01 -0.02~~~~~~~~~~ "--'" <, ~ s t--------t-----~--------_~~~~···~···········.11 0 5 -------~1 ~~ 10 __ ~~ 20 15 25 ~ ~ 30 35 Elk Density (animals/km2) I Year 1 -----------2 ----- Contra.t ss X.an 1 1 l. l. l. 1 14.14093013 3.21423414 8.79616897 19.82479149 20.26095478 0.96845746 14.14093013 3.21423414 8.796l.6897 19.82479l.49 20.26095478 0.96845746 7.61 1.73 4.74 10.67 10.9l. 0.52 Vear l. control v. other. control v. 8 81k/02 control v. 15 .1k/laa control. v. 31 .1k/ka 1in •• r erreeta quadratiC .rrecta l. 1 1 1 1 1 8.0424847 0.8677961 10.6707754 7.5537260 9.0774631 3.3735283 8.0424847 0.8677961 10.6707754 7.5537260 9.0774631 3.3735283 7.23 0.78 9.59 6.79 8.16 3.03 0.0361 0.4112 0.0212 0.0404 0.0290 0.1323 Vear 2 control v. other. contro~ v. 8 .1k/02 control v. 15 .1k/ka contro.! v. 31 .1k/a 11n.ar errect. quadratiC .rrioc:ta 1 1 1 1 1 1 9.6538543 3.7260751 2.1417777 17.7125711 16_1520238 0.03559.6 9.6538543 3.7260751 2.1417777 17.7825711 16.1520238 0.0355986 3.71 1.43 0.82 6.84 6.21 0.01 0.1023 0.2765 0.3992 0.0399 0.0470 0.9107 Vear 3 control v. other. 8 .1k/02 contro1 control l.5.1.k/a control 31 .1.k/a 11n •• r etteeta quadratiC .rrecta 1 1 1 1 1 1 0.32522533 0.05924.41 0.16554957 0.557441.74 0.58445366 0.00318937 0.32522533 0.05924841 0.l.6554957 0.55744174 0.58445366 0.00318937 2.74 0.50 1.39 4.70 4.92 0.03 0.1489 0.5063 0.2823 0.0733 0.0683 0.8752 Contrast DP Years control va other. contro~ v. 8 e1k/02 control v. l.5e1k/a control va 3l.e1k/ka 11near e~t.ct. quadratiC erreeta Square P Va~u. 3 Pr > P A~~ v. v. v. 0.0329 0.2364 0.0724 0.0171 0.0l.64 0.4974 Figure 28. Effects of elk density on removal (intake + trampling) of standinq dead perennial grass by cattle. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �246 Forage Class=Total Herbs 0.181 0.171 -e <, 0.161 N 0.151 0.141 <, 0.131 QD 0.121 i!; 0.111 ::: 0.101 -' ~ u 0.091 >. 0.081 ~ 0.071 0.061 (!l > 0.051 0 0.041 v 0.031 0:: 0.021 v 0.011 QD 0.001 (!l ~ -0.009 '- -0.019 -0.029 Age=Standing Dead a a ~---+---o 5 I Year Contrast DP Contrast SS Al.l.Year. eontrol. va other. control va 8 el.k/D2 control. va 15 el.k/leJD control. va 31 el.k/1nI linear err.ct. quadratic e~~ecta 1 1 1 1 1 1 Yea.r 1 v. others control control. v. 8 el.k/D2 control v. 15 elk/1nI contro.l v. 31 .l.k/1nI linear .~~.cta quadratic err.eta 1 1 1 1 1 1 11.36637"7 1.55060"5 16.01,,7389 9.06701"6 10.69.9170 6.251"323 Y •• ", 2 contro1 v. other. contro~ 8 .l.k/D2 control v. 15 el.k/1nI control 31 .1.k/1nI 1.1n.a", .~~ect. quad",atic .~~.cta 1 1 1 1 1 1 Ye.., 3 control v. other. control. v. 8 .1.k/D2 control 15 el.lc/1nI control 31 .1.k/1nI 1in •• r .~~acta .~~acta quadratic 1 1 1 1 1 1 v. v. v. v. 22.30"70565 5.26771120 15.09237238 29.03"59160 29.56826921 2.303.•.• 050 10 15 20 25 Elk Density (animals/km2) 1 Mean Square F Va~u. Pr> 0.0174 0.1652 0.0368 0.0100 0.0096 11.3663747 1.55060"5 16.01"7389 9.06701"6 10.6989170 6.251"323 11.30 1.5.• 15.93 9.02 10.6" 6.22 0.0152 0.2606 0.0072 0.0239 0.0172 0.0"69 16.377563. 5.375.320 ".6586515 29.5"91690 27 ••156076 0.0052••1 16.3775638 5.3758320 4.6586515 29.5"91690 27.8156076 0.0052.81 6.02 1.98 1.71 10.&6 0.0"96 0.2095 0.5.03075. 0.1693312" 0.32329962 0.5.030758 0.76274"90 0.04047418 0.1693312" 0.32329962 0.7.47783. 0.76274490 0.0"047418 10.22 0.00 4.45 1.30 2.48 6.02 5 ••5 0.31 35 3 P 10.57 2.50 7.15 13.76 14.01 1.09 0.7 ••• 7783. 22.30"70565 5.26771120 15.09237238 29.03"59160 29.56826921 2.303.•.• 050 2 ----_ 30 0.336" 0.2386 0.0165 0.0187 0.9663 0.079" 0.2979 0.166 •• 0.0"96 0.0519 0.5975 Figure 29. Effects of elk density on removal (intake + trampling) of dead herbaceous biomass (annual grass + perennial grass + forbs) by cattle. Vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �247 Forage Class=Total Cover 2 50 ~ 40 :> e c..; >, ;-30 c :0= U J:::::::::"'"",.I-.... - -.t ------ ···---H --------4t--------------- 20 o 5 10 15 20 25 30 35 Elk Density {animals/km2} YEAR Contrast 1 .----- 2 --- 3 lI.an SqWlr. P Val.••• 2114.7018126 11 .•• 3343004 2211.7779789 240.63385110 214.9306032 96.5266871 40.23 16.16 32.33 34.01 30.37 13.6" 0.0007 0.0070 0.0013 0.0011 0.0015 0.0102 394.3948911 117.773307 294.584713 425.577572 414.180467 78.143150 394.3941198 117.773307 294.584713 425.577572 414.180467 711.143150 11.70 3.49 8.74 12.63 12.29 2.32 0.0141 0.1108 0.0254 0.0120 0.0127 0.17117 1 1 1 1 1 1 0.027586511 0.19245666 0.2111104501 0.095311302 0.30655470 0.012.4671 0.027586511 0.19245666 0.281104501 0.095311302 0.30655470 0.012.4671 0.00 0.03 0.05 0.02 0.05 0.00 0.9490 0.11661 0.11366 0.9054 0 ••316 0.9652 1 1 1 1 1 1 114.63211640 65.71115077 72.21272.3 35.1631581 20.1390304 65.0256343 114.632.640 65.71.5077 72.2127283 35.16315111 20.1390304 65.0256343 4.97 3.116 4.24 2.07 1.1. 3.112 0.0673 0.0971 0.0.51 0.2007 0.3185 0.09115 OF Contra.t ss All Year. control va others contro~ va II .1k/ka2 control va 15 elk/lao control VIS 31 elk/lao 11n.a.r e~~ect. quadratic effect. 1 1 1 1 1 1 2114.70111126 114.3343004 228.77797119 240.633115110 214.9306032 96.52661171 Y.ar 1 control vs others control vs 8 .1k/ka2 control va 15 elk/lao control va 31 e1k/1ao linear effects quadratic effects 1 1 1 1 1 1 Year 2 control vs other. control vs 8 .1k/ka2 control vs 15 elk/lao eontrol VIS 31 elk/lao linear effects quadratic effects Year 3 control vs other. control vs elk/ka2 control vs 15 el.k/Iao control vs 31 elk/lea linear effects quadratic effects • - Pr > F Figure 30. Effects of elk density on canopy coverage of herbaceous biomass (annual grass + perennial grass + forbs) at the end of the spring grazing season. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �248 Forage Class=Annual Grass 17 16 15 1413 -12 ~11 :... il) >0 u 10 9 >. 8 7 c 6 :tl U 5 4 Co 0 3 2 1 0 5 0 15 10 20 25 30 35 Elk Density {animals/km2} YEAR COntrast A1.1.Year. contro.! v. others control. v. 8 e1.k/-.z control v. 15 elk/lao control v. 3], e1.k/1ao ~in.ar .rreet. quadratiC e~~ecta Dl" ]. 1 1. ]. 1. 1. contrast 55 - 1 .•.•.• 2 Xean SqUare 37.55320290 35.02282750 29.46399955 25.4231.1.011 1.8.9682451.3 25.03768704 37.55320290 35.02282750 29.46399955 25.423].1.01], 18.9682451.3 25.03768704 --- F Value 3 Pr > 1" 4.10 3.82 3.21. 2.77 2.07 2.73 0.2922 0.30],], 0.3239 0.3443 0.3868 0.3464 1.04.993802 90.1.65598 84.8271.35 74.970905 59.004997 65.933473 7.31. 6.28 5.90 5.22 4.1.], 4.59 0.2256 0.24],8 0.2485 0.2627 0.29],8 0.2780 V •• r 1. control v. other. control. v. 8 elk/1aI2 control v. 1.5 el.k/Iao control. va 3], el.Jc/1ao linear e~~eeta quadratic e~~eeta 1. 1. 1. 1.04.993802 90.165598 84.827],35 74.970905 59.004997 65.933473 Vear 2 contro.l va other. contro.! va 8 el.k/-.z control va ].5 el.k/Iao contro.! va 3]. el.k/Iao lin •• r e~~ect. quadratiC e~~eeta 1. 1. 1. 1. 1. 1. 0.1.1427738 0.52489969 0.0271.4899 0.00276740 0.02431.1.35 0.26979644 0.],1.427738 0.52489969 0.027],4899 0.00276740 0.0243],],35 0.26979644 0.05 0.25 0.01. 0.00 0.01. 0.1.3 0.8543 0.7052 0.92.0 0.9769 0.9319 0.7.].2 ]. 0.000.6585 0.0009141. 0.0007],651 0.0004.625 0.00032302 0.00075169 0.00086585 0.00091.418 0.0007].65]. 0.00048625 0.00032302 0.00075169 91..41. 96.52 75.65 5],.34 34.1.0 79.36 0.0663 0.0646 0.0729 0.0 •• 3 0.1.0.0 0.07],2 Y.ar 3 control va other. control. va 8 elk/-.z control va 1.5 elk/lao control v • 3]. e1.k/1ao .lin•• r e~:feeta quadratic .ereeta ]. ]. ]. 1. 1 ]. 1 ]. Figure 31. Effects of elk density on canopy coverage of annual grass at the end of the spring grazing season. Vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �249 Forage Class=Perennial Grass 14 13 12 11 _10 );~ .'- •.. QJ >- 9 8 0 u 7 >.. 0. 6 0 c 5 :c u 4 1······················ 1----__ 3 2 1 ················· ·····1····· . ----t----- ---------- +1 . ·················-I ---- --- ] ---1 0 0 5 10 15 25 20 30 35 Elk Density (animals/km2) YEAR Contrast Dl" - 1 Contr ••t 5S Mean SqUare .•.•.• 2 P Va~u. --- 3 Pr > 1" 1o.l.l. Year. contro.l va other. contro1 va 8 el.k/~ contro~ va 15 el.k/n contro.l v. 31 el.k/n 1in •• r .~-r.ct..s quadratic .~~ecta 1 1 1 1 1 1 0.00621144 1.99284448 2.71596508 10.58038808 14.50247489 15.99523287 0.00621144 1.99284448 2.71596508 10.58038808 14.50247489 15.99523287 0.00 0.58 0.79 3.06 4.19 4.63 0.9676" 0.4765 0.4096 0.1309 0.0865 0.0750 Year 1 va other. control control v. 8 el.k/~ contro.! v. 15 elkin control v. 31 .l.k/_ l.ln ••r e~~acta quadratic .~~ecta 1 1 1 1 1 1 0.210574. 9.4623374 0.6877041 7.735'422 15.9662046 14.0105597 0.2105748 9.4623374 0.6877041 7.7358422 15.9662046 14.0105597 0.07 3.06 0.22 2.50 5.16 4.53 0.8029 0.1309 0.6540 0.1649 0.0635 0.0774 va other. contro.! v. 8 .l.k/~ control. v. 15 .l.k/_ contro.! v. 31 .l.k/n lin •• r .~rec:t. quadratic .~racta 1 1 1 1 1 1 0.09272954 0.05915866 3.72415676 2.03668851 1.936'9716 7.2007'969 0.09272954 0.05915866 3.72415676 2.03668851 1.93689716 7.20078969 0.08 0.05 3.18 1.74 ]..65 6.15 0.7879 0.8297 0.1249 0.2354 0.2459 0.0479 Y.ar 3 control v. other. control v. 8 el.k/~ contro.! v. 15 .l.k/n control v. 31 .a/Iao l.ln •• r erracta quadratiC .rracta 1 1 1 1 1 1 0.809'3284 0.76424804 0.00909450 2.0319520' 1.46051563 0.25067455 0.80983284 0.76424.04 0.00909450 2.0319520. 1.46051563 0.25067455 0.53 0.50 0.01 1.34 0.96 0.17 0.4923 0.5043 0.9408 0.2909 0.3642 0.6983 Y.ar 2 control Figure 32. Effects of elk density on canopy coverage of perennial grass at the end of the spring grazing season. Vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �250 Forage Class=Shrub 29 28 27 26 25 _24 ~23 ,",22 ~ 21 820 >'19 0. o 18 al 17 u 16 15 14 13 12 11 5 0 10 15 20 25 30 35 Elk Density (animals/km2) YEAR Contrast - 1 .•.••• 2 -_. 3 ,. DP Contra.t 55 Xean SqUare P Va~u. lll. years contro~ other. control v. 8 el.k/1<a2 control v. 15 e1k/1nI control va 31 el.k/1nI 11near ertecta quadrat1c errecta 1 1 1 1 1 1 107 ••96165. 66 ••943027 134.5477783 32.0949135 20.6.28141 122.6617930 107.896165. 66.8943027 134.5477783 32.0949135 20.6.28141 122.6617930 15.62 9.69 19.48 4.65 3.00 17.76 0.0075 0.020. 0.0045 0.0745 0.1342 0.0056 Year 1 control v. other. v. 8 el.k/1<a2 control control 15 el.k/1nI control 31 el.k/1nI 11near err.cta quadratic ertects 1 1 1 1 1 1 86.6968369 54.7192451 73.9467323 46.3.97612 32.5130263 53.7411101 86.6968369 54.7192451 73.9467323 46.3897612 32.5130263 53.7411101 14.46 9.13 12.34 7.74 5.42 8.97 0.0089 0.0234 0.0126 0.0319 0.0587 0.0242 Year 2 control v. other. contro.! 8 al.k/1<a2 control v. 15 a1k/1nI control v. 31 al.k/1nI l.1near attects quadratic ettecta 1 1 1 1 1 1 0.10102930 0.17972678 5.54215152 1.32632669 0.64876543 6 ••08l.l.95O 0.10102930 0.17972678 5.54215152 1.32632669 0.64876543 6.8081l.950 0.02 0.03 1.06 0.25 0.12 1.30 0.8942 0.8593 0.3439 0.6332 0.7372 0.2983 1 1 1 1 1 1 69.9294057 5l..738611. .3.4933737 17.24855.9 ••••35211 .5.4307350 69.9294057 51.7386114 83.4933737 17.24.5589 8.8835211 85.4307350 3.72 2.75 4.45 0.92 0.47 4.55 0.1019 0.14.1 0.0796 0.3749 0.5173 0.0769 v. v. v. v. v. v. Y.ar 3 control. other. control 8 al.k/1<a2 control 15 el.k/1nI control 31 al.k/_ 11naar ettecta quadratic attects v. v. Pr P Figure 33. Effects of elk density on canopy coverage of shrubs at the end of the spring grazing season. Vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �251 Forage Class=Perennial Forb 61 5J j j 1 1 ~ 4. ;jJ ":"'1 > o· '[ u3 ~ 0 __1__ ~c? U I 1 fr ~~~-~ r ~--~-~_ ------- .::.·.·.····_···-1-··.............. I::::':'·-::=~-:::::.-:::::,,· fi ·························:::::1 •. 0 0 5 10 15 25 20 30 35 Elk Density (animals/km2) YEAR - 1 "'." 2 __ a 3 Dr Contrast 5S Xean Square A11 Y.ar. control. v. others contro.! va 8 e1k/n2 control v. 15 e1k/n control. va 31 •• 1k/n linear .t!~ect. quadratic errecta 1 1 1 1 1 1 0.82055529 0.27061652 0.02933343 2.33288970 2.18138675 0.22755608 0.82055529 0.27061652 0.02933343 2.33288970 2.18138675 0.22755608 0.63 0.21 0.02 1.78 1.67 0.17 0.4586 0.6653 0.8859 0.2302 0.2442 0.6912 Year 1 control v. other. control. v. 8 e1k/n2 control v. 15 elkin contro.l v. 31 elkin 11n •• r errecta quadratic errecta 1 1 1 1 1 1 2.11198217 0.67938777 0.77630054 3.43891518 3.25651384 0.01496561 2.11198217 0.67938777 0.77630054 3.43891518 3.25651384 0.01496561 1.63 0.52 0.60 2.65 2.51 0.01 0.2488 0.4962 0.4682 0.1543 0.1639 0.9179 Year 2 control. v. other. control. v. 8 e1k/n2 control v. 15 e1k/n contro.! 31 e1k/_ 1inear errecta quadratiC e·rrecta 1 1 1 1 1 1 0.03767560 0.00284659 0.00094345 0.20503965 0.21556661 0.06848496 0.03767560 0.00284659 0.00094345 0.20503965 0.21556661 0.06848496 0.14 0.01 0.00 0.77 0.81. 0.26 0.7198 0.9210 0.9545 0.4141 0.4030 0.6302 1 1 1 1 1 1 0.00614631 0.00054.67 0.30660056 0.11441679 0.0.368452 0.47179741 0.00614631 0.00054867 0.30660056 0.11441679 0.08368452 0.47179741 0.02 0.00 0.8. 0.33 0.24 1.36 0.8985 0.9696 0.3.35 0.5.67 0.6408 0.2878 Contrast v. v. Year 3 control. other. control. v. 8 e1k/ka2 control. v. 15 e11c/_ control v. 31 elk/_ lin •• r errecta quadratiC errecta F Value Pr > r Figure 34. Effects of elk density on canopy coverage of forbs at the end of the spring grazing season. vertical bars give ± 1 standard error. Test of specific hypotheses are shown in the table of orthogonal contrasts. �252 Appendix 1. Summary of canopy coverage data by species. Elk Density 0 (animals/km2) 8 15 31 Canopy Canopy Canopy Canopy Cover (% ) Cover ( % ) Cover ( % ) Cover ( %) MEAN S.E. MEAN S.E. MEAN S.E. MEAN S.E. Forage Class species YEAR Annual Forb Alyssum desertorum 1 0.17 0.05 0.06 0.05 0.14 0.05 0.03 0.02 2 0.01 0.01 0.00 3 0.00 0.00 0.00 0.00 0.01 0.00 0.01 1 10.5 4.65 5.94 1.08 3.55 0.44 3.14 1.84 2 0.70 0.29 0.56 0.20 0.56 0.35 1.05 0.61 3 0.04 1 0.02 0.01 0.02 0.00 0.04 0.04 0.01 0.01 2 0.00 1 0.02 Annual Grass Bromus tecto rum Festuca octoflora · · · 0.03 0.03 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.00 Perennial Forb Allium acuminatum · 2 Antenaria parvif. 1 Arenaria fendleri Artemisia frigida Astragalus drum. 3 · 0.02 1 · 0.10 Values shown as . · 0.01 3 0.01 1 0.07 0.05 0.15 · 0.13 · 0.01 2 0.11 0.10 0.13 · 0.02 3 0.08 · 0.06 · 0.07 · 0.07 · 0.03 1 0.08 · 0.04 0.02 0.07 0.02 0.03 0.01 2 0.07 (CONTINUED) * 0.00 indicate species was not present. �253 Appendix 1. Summary of canopy coverage data by species. Elk Density 0 (animals/krn2) 8 15 31 Canopy Canopy Canopy Canopy Cover (% ) Cover ( % ) Cover (% ) Cover (% ) MEAN S.E. MEAN S.E. MEAN S.E. MEAN S.E. Forage Class Species YEAR Perennial Forb Astragalus drum. 3 Astragalus spat. 1 0.01 3 0.04 1 0.17 0.15 0.03 0.00 0.07 0.02 0.01 0.00 2 0.04 . 0.01 0.00 3 0.13 . 0.03 0.00 0.03 0.01 Aster spp. 1 0.01 Balsamorhiza sag. 1 0.14 2 0.07 cela 2 0.13 Chaenactis doug. 1 Cirsium undulatum 1 · 0.55 2 · 0.03 3 · 0.28 Astragalus purse Commandra umbo 0.01 · 0.06 0.05 · 0.06 . 0.01 · 0.10 · 0.25 0.08 · 0.01 · 0.01 0.01 . 0.02 0.01 1 0.23 0.09 0.11 0.04 0.28 0.09 0.11 0.05 2 0.09 0.05 0.09 0.02 0.09 0.02 0.04 0.03 3 0.05 0.04 0.06 0.02 0.04 0.01 0.04 0.02 (CONTINUED) * · 0.01 Values shown as . indicate species was not present. �254 Appendix 1. Summary of canopy coverage data by species. Elk Density 0 (animals/km2) 8 15 31 Canopy Canopy Canopy Canopy Cover (% ) Cover (% ) Cover (% ) Cover ( % ) MEAN S.E. MEAN S.E. MEAN S.E. MEAN S.E. Forage Class Species YEAR Perennial Forb Plox hoodii 2 0.15 0.08 0.15 0.07 0.46 0.03 0.06 0.04 3 0.06 0.03 0.10 0.05 0.12 0.06 0.05 0.01 Plox longifolia 1 2 0.01 3 0.01 · 0.01 · 0.00 · 0.02 · 0.00 · 0.01 · 0.01 · · 0.00 0.00 · · 0.01 Plantago patgonica 1 Psoralidiurn lanc. 1 0.86 · 0.02 2 0.02 · 0.05 3 0.10 1 0.17 0.06 0.21 0.07 0.18 0.07 0.15 0.02 2 0.10 0.07 ·0.09 0.03 0.07 0.03 0.09 0.01 3 0.14 0.04 0.08 0.04 0.20 0.10 0.09 0.04 Sparalcea cocine Tragopogon dubius · 0.03 · 1 1 0.61 0.61 0.03 0.00 0.01 2 Unknown (CONTINUED) · 0.01 · 0.00 · 0.09 0.03 2 Trifolium gymnocar 0.08 0.07 · 0.00 · · 0.01 0.00 0.00 0.00 0.00 3 0.01 1 0.08 0.07 0.81 0.73 0.12 2 0.06 0.04 0.04 0.00 0.01 3 0.02 0.02 0.02 0.00 0.07 0.03 0.07 · · 0.04 0.02 0.04 �255 Appendix 1. Summary of canopy coverage data by species. Elk Density o (animals/km2) 15 8 31 Canopy Canopy Canopy Canopy Cover (%) Cover (%) Cover (%) Cover (%) MEAN S.E. MEAN S.E. MEAN S.E. MEAN S.E. Forage Class Species YEAR Perennial Forb Cryptantha flava 1 · 0.02 · . 3 Erigeron eatonii 1 Erigeron spp. Lupinus argenteus Lupinus polyphy. Plox hoodii · 0.01 · 0.11 0.04 0.06 0.03 0.06 0.02 1 0.06 2 0.04 0.03 0.06 0.02 0.05 0.02 0.01 0.00 3 · 0.06 1 · 0.02 2 · 0.01 · 0.01 0.00 0.01 0.00 1 0.56 0.24 0.31 0.14 0.43 0.32 0.23 0.02 2 0.22 0.10 0.06 0.05 0.21 0.17 0.20 0.09 3 0.28 0.07 0.01 2 0.33 0.28 0.53 0.28 0.23 0.07 0.24 0.13 3 0.39 0.20 0.68 0.36 0.15 0.03 0.26 0.09 · 0.59 0.06 0.22 0.05 1 0.31 0.14 0.36 0.15 0.33 0.22 0.14 0.07 (CONTINUED) * 0.02 0.16 2 Eriogonum oval. 0.34 0.10 0.03 Values shown as . indicate species was not present. �256 Appendix 1. Summary of canopy coverage data by species. Elk Density 0 (animals/km2) 8 15 Canopy Canopy Cover (% ) Cover (%) 31 Canopy Canopy Cover (% ) Cover ( %) MEAN S.E. MEAN S.E. MEAN S.E. MEAN S.E. Forage Class Species YEAR Perennial Grass Agropyron smithii 1 1. 28 0.75 1.02 0.66 0.88 0.58 0.17 0.05 2 0.36 0.11 0.44 0.22 0.30 0.07 0.14 0.05 3 0.12 0.06 0.05 0.01 0.52 0.39 0.02 0.01 Agropyron spicatum 1 2 Elymus cinereus 1 0.07 0.03 0.61 2 0.01 1 · 0.02 · 0.19 Koleria macrantha oryzopsis hymenoid. Poa spp. (CONTINUED) · 0.01 · 0.92 0.87 . · 3 Hilaria jamesia 1.09 0.02 0.02 3 Agropyron trachy. · · 0.00 0.16 0.03 1 0.02 2 0.15 3 0.11 1 1. 39 0.37 1.24 0.36 1.43 0.38 0.75 0.34 2 0.16 0.02 0.19 0.06 0.26 0.15 0.18 0.06 3 0.03 0.01 0.02 1 0.35 0.18 0.62 0.20 0.53 0.32 0.18 0.09 2 0.21 0.09 0.21 0.07 0.03 0.01 0.05 0.02 3 0.11 0.03 0.05 1 0.72 0.13 0.54 0.13 0.58 0.16 0.37 0.08 · · 0.03 0.01 0.05 0.02 0.02 . 0.04 0.01 �257 Appendix 1. Summary of canopy coverage data by species. Elk Density 0 (animals/km2) 8 15 31 Canopy Canopy Canopy Cover ( % ) Cover (% ) Cover ( %) Canopy Cover ( % ) MEAN S.E. MEAN S.E. MEAN S.E. MEAN S.E. Forage Class species YEAR Perennial Grass Poa spp. 2 0.30 0.09 0.31 0.07 0.39 0.13 0.21 0.03 3 0.09 0.04 0.03 0.01 0.06 0.03 0.09 0.02 1 0.15 0.08 0.54 0.07 0.12 0.03 0.13 0.06 2 0.19 0.05 0.09 0.02 0.02 0.01 0.03 0.00 3 0.06 0.02 0.03 0.01 0.01 1 5.88 0.93 8.10 0.69 5.97 1. 40 5.95 1.62 2 2.78 0.17 2.97 0.60 4.60 0.84 2.25 0.38 3 2.41 0.28 2.00 0.55 2.25 0.78 1. 47 0.59 1 0.13 0.00 0.14 2 0.43 3 0.06 1 15.4 2.93 14.8 0.79 11. 2 1.66 14.6 0.68 2 13.1 1.98 14.0 2.24 10.2 2.10 14.5 0.71 3 16.7 4.31 14.2 1.57 11. 3 2.53 17.0 1.65 1 0.29 0.08 0.32 0.32 0.19 0.13 0.30 0.06 2 0.24 0.12 0.13 0.06 0.22 3 0.22 0.04 0.56 1 1.66 0.47 0.81 0.46 1.93 0.96 0.88 0.29 2 0.83 0.23 0.33 0.21 0.92 0.38 0.64 0.16 3 1.79 1. 24 0.31 0.12 0.54 0.24 0.42 0.18 sitanion histrix Stipa comata Shrub Artemisia cana Artemisia triden. Chrysothamnus nas. Chrysothamnus vic. (CONTINUED) . . 0.47 0.05 · 0.02 0.00 · 1.64 · 0.56 · · 0.50 · 0.43 0.43 · 0.17 · · 0.14 0.11 0.38 0.15 0.16 0.08 �258 Appendix 1. Summary of canopy coverage data by species. Elk Density 0 (animals/km2) 8 Canopy Canopy Cover (% ) Cover (%) 15 31 Canopy Cover ( %) Canopy Cover ( %) MEAN S.E. MEAN S.E. MEAN S.E. MEAN S.E. Forage Class Species YEAR Shrub Eriogonum mic. 1 0.11 0.01 0.14 0.06 0.14 0.10 0.11 0.02 2 0.10 0.05 0.10 0.05 0.05 0.02 0.06 0.01 3 0.12 0.01 0.11 0.06 0.16 1 0.10 0.02 0.03 0.02 0.14 0.02 0.32 0.24 2 0.05 0.02 0.10 0.07 0.24 0.05 0.09 0.04 3 0.18 0.09 0.10 0.08 0.18 0.06 0.06 0.03 Gutierrezia saro. Haplopappus accal. 1 · 0.02 2 · · 0.02 3 Leptodactylon pun. Opuntia polyacan. Purshia· tridentata Tetrademia spinosa Values shown as . 0.10 0.08 0.06 1 4.37 4.23 0.62 0.40 1.51 0.98 0.54 0.41 2 0.24 0.15 0.27 0.21 0.77 0.32 0.30 0.13 3 1.64 1. 42 0.25 0.23 0.49 0.35 0.07 0.05 1 0.60 0.39 0.19 0.14 0.99 0.92 0.09 0.06 2 0.57 0.41 0.48 0.43 0.56 0.50 0.13 0.12 3 0.78 0.63 0.66 0.46 0.54 0.52 0.16 0.15 1 0.20 2 0.05 0.03 0.05 3 0.14 0.06 1 0.54 0.41 0.05 0.02 0.15 0.07 0.20 0.08 2 0.13 0.03 0.03 0.01 0.34 0.04 0.19 0.13 . 0.09 (CONTINUED) * · indicate species was not present. · 0.16 · · 0.38 · 0.19 0.41 �259 Appendix 1. Summary of canopy coverage data by species. (an i.ma Ls zkmz ) Elk Density 0 8 Canopy Cover ( %) 15 31 Canopy Canopy Canopy Cover (% ) Cover (% ) Cover ( % ) MEAN S.E. MEAN S.E. MEAN S.E. MEAN S.E. Forage Class Species YEAR Shrub Tetrademia spinosa 3 All species Total Cover 0.16 0.09 0.08 1 46.8 4.47 37.9 2 20.9 1. 08 21.2 3 25.4 4.81 18.8 . 0.42 0.08 0.16 0.07 1. 76 32.8 0.72 30.0 3.54 0.84 20.5 2.38 20.6 0.89 0.22 18.5 1. 81 20.6 0.82 �260 Appendix 2. Summary of canopy coverage data by forage class. Elk Density 0 (animals/km2) 8 15 Canopy Canopy Canopy Cover (% ) Cover (% ) Cover (%) 31 Canopy Cover (% ) MEAN S.E. MEAN S.E. MEAN S.E. MEAN S.E. Forage Class YEAR Annual 1 0.17 0.05 0.06 0.05 0.14 0.05 0.03 0.02 2 0.01 0.01 0.00 3 0.00 0.00 0.00 0.00 0.01 0.00 0.01 1 10.6 4.64 5.95 1.07 3.58 0.47 3.15 1.85 2 0.70 0.29 0.56 0.21 0.56 0.35 1.05 0.61 3 0.04 1 3.36 0.14 2.69 1. 28 2.64 0.88 1.85 0.22 2 0.94 0.38 0.89 0.39 0.96 0.08 0.57 0.21 3 0.99 0.16 0.97 0.45 1.45 0.31 0.72 0.17 1 9.83 1.69 12.3 0.95 10.5 0.29 7.56 1.65 2 4.01 0.18 4.21 0.93 5.59 1.14 2.85 0.53 3 2.85 0.26 2.13 0.58 2.92 1.00 1.68 0.65 1 22.9 2.71 16.9 1.02 15.9 1.15 17.4 0.14 2 15.2 1.06 15.6 1.88 13.3 0.87 16.2 0.37 3 21.6 4.64 15.7 0.81 14.1 1.24 18.2 1. 33 1 46.8 4.47 37.9 1.76 32.8 0.72 30.0 3.54 2 20.9 1.08 21. 2 0.84 20.5 2.38 20.6 0.89 3 25.4 4.81 18.8 0.22 18.5 1.81 20.6 0.82 Annual Forb Grass Perennial Forb Perennial Grass Shrub Total Cover . . 0.03 0.03 0.00 0.00 0.00 0.00 0.00 0.01 0.01 � https://cpw.cvlcollections.org/files/original/5e8871869a86359d187d1d8bb8d38b57.pdf 1e106350dfaaebd97d677d936a24cc3e PDF Text Text 1 Colorado Division of Wildlife Wildlife Research Report October 1989 JOB FINAL REPORT State of __~C~o~l~o~r~a~d~o~ Project Migratory Game Bird Research 01-03-212 Work Plan _1_ Job Title: : Job 14 Ecological studies of the flightless period of ducks in Colorado Period Covered: Author: _ 01 April 1988 through 31 March 1989 Michael R. Szymczak Bersonnel: Michael R. Szymczak and James K. Ringelman, Wildlife Colorado Division of ABSTRACT All data from this project have been collected and partially analyzed. This study addressed survival, habitat use, behavior, energetics, condition, food habits, weight dynamics, and the duration of the flightless period of ducks in North Park, Colorado. Data were gathered on all species, but most information were obtained for gadwall (Anas· strepera) or mallards (Anas platyrhynchos). Because of the comprehensive nature of the study, a monograph entitled "The ecology, behavior, and energetics of post-breeding waterfowl in Colorado" is currently being planned. All additional analysis and publication preparation will be conducted under Work Plan 22, Job 2, Migratory Bird Publications . • Prepared by: ?/I,;.R.,f 7? 400/ Michael R. Szymczak Wildlife Researcher C James K. Ringelman Wildlife Researcher C ��3 Colorado Division of Wildlife Wildlife Research Report October 1989 JOB PROGRESS REPORT State of __~C~o~l~o~r~a~d~o~ Project 01-03-212 Work Plan 1 Job Title: : Job Migratory Game Bird Research 15 Development and use of a physiological condition index for monitoring wintering mallard nutrient reserves Period Covered: Author: _ 01 April 1988 through 31 March 1989 Michael R. Szymczak Personnel: Michael R. Szymczak and James K. Ringelman, Colorado Division of Wildlife ABSTRACT Data for this project have been collected and most of it has been analyzed. To date, 2 manuscripts have been published, another is in draft form ready for review, and 2 others are planned using data collected under this study. All additional analysis and publication preparation will be conducted under Work Plan 22, Job 2, Migratory Bird Publications. Completed and planned publications are: Ringelman, J. K., and M. R. Szymczak. 1985. A physiological condition index for wintering mallards. J. Wildl. Manage. 49:564-568. Szymczak, M. R., and J. K. Ringelman. 1986. Differential habitat use of patagial-tagged female mallards. J. Field Ornitho1. 57:230-232. Ringelman, J. K., D. C. DeLong, and M. R. Szymczak. Geographical variation in body mass· and size of wintering mallards (draft). Ringelman, J. K., and M. R. Szymczak. Proximate and ultimate determinants of field-feeding behavior in mallards (planned). Szymczak, M. R., and J. R. Ringelman. The influence of weather on body mass dynamics of northern wintering mallards (planned). Prepared by: yn;_g.I7? ~ f Michael R. Szymczak Wildlife Researcher C ~~~ JamesK.~ Wildlife Researcher C ��5 Colorado Division of Wildlife Wildlife Research Report October 1989 JOB FINAL REPORT State of __~C~o~l~o~r~a~d~o Project 01-03-212 Work Plan Job Title: _1_ : Job MigratohY Game Bird Research 16 Field-feeding ecology of mallard ducks Period Covered: Author: _ 01 April 1988 through 31 March 1989 Michael R. Szymczak Personnel: Michael R. Szymczak and James K. Ringelman, Wildlife Colorado Division of ABSTRACT All data from this project have been collected and analyzed. An outline for a manuscript entitled "Foraging rates of mallards in cornfields: the effects of post-harvest treatments" has been prepared. Additional publication preparation will be conducted under Work Plan 22, Job 2, Migratory Bird Publications. Michael R. Szymczak Wildlife Researcher C James K. Ringelman Wildlife Researcher C ��7 Colorado Division of Wildlife Wildlife Research Report October 1989 JOB PROGRESS REPORT State of __~C~o~l~o~r~a~d~o~ Project Work Plan 01-03-212 <W-88-R) 1__ Job _ Migratory Game Bird Research 17 Job Title: Habitat use by wintering mallards along the Front Range of Colorado Period Covered: Authors: I April 1988 through 31 March 1989 James K. Ringelman and Michael R. Szymczak Personnel: R. Falise, M. James, R. Westfall, Colorado State University; L. Roberts, Front Range Land and Cattle Company; J. Corey, Colorado Division of Wildlife. ABSTRACT Twenty-five mallards were radio-marked at Lonetree Creek and Chestnut Slough during December 1988, and an additional 11 maliards were instrumented in January on Chestnut Slough. Movements and habitat use of radio-marked and unmarked mallards were measured from December through February to document relationships among hunting activity, weather and habitat selection. Disturbance was further evaluated by simulating hunting activity during January and February, then evaluating mallard behavioral responses. Scan sampling was used to document group behavior by habitat type and time of day. Temperatures were above normal in January and far below normal in February. Consequently, habitat availability caused by ice conditions decreased rapidly in late winter, concentrating birds on the remaining open water areas. In response to these conditions, along with habitat management practices intended to minimize disturbance at Chestnut Slough, the average home range size of radio-marked birds was smaller than in previous winters. Mallards preferred warm-water sloughs and rivers, but made infrequent use of ponds and most reservoirs. Responses of instrumented birds to hunting disturbance, measured using an accumulative disturbance index, varied among individuals and in relation to weather conditions. Cold weather reduced the duration of avoidance following disturbance. Shots fired from areas adjacent to the study wetland generally did not elicit movements, and birds often moved independent of hunting disturbance. During simulated hunting disturbance, most mallards returned to roost at Chestnut Slough 10 to 13 hours following departing. As in previous years, resting and swimming were the principal activities, f~llowed by feeding, preening and walking. ��9 HABITAT USE BY WINTERING MALLARDS ALONG THE FRONT RANGE OF COLORADO James K. Ringe1man Michael R. Szymczak P. N. OBJECTIVES 1. Relate mallard habitat use to the physical characteristics of wetlands, aquatic and upland plant communities, wetland macroinvertebrate populations, weather, and hunting regimes. 2. Characterize mallard use of wetlands through time budget techniques. 3. Document the composition of the wetland community within the study area, and relate wetland use by mallards to availability. SEGMENT OBJECTIVES 1. Capture and radio-mark 24 mallards during early December. marked sample equally by age and sex. Divide the 2. Monitor the diurnal movements of instrumented mallards using aerial and vehicle-mounted tracking systems. Code bird locations using a Universal Transverse Mercator (UTM) grid system. 3. Conduct aerial tracking flights once a week, or more frequently if weather conditions or bird movements warrant. 4. Determine the availability of ice-free wetlands daily using a representative sample of wetland types. 5. Monitor hunting regimes on key wetlands to determine the effect of hunting disturbance on movements of radio-marked mallards. Simulate the effects of hunting with controlled disturbance during the post-season period. 6. Obtain National Weather Service records for daily temperature, wind and snowfall for a representative site in the study area. 7. Quantify behavior of marked and unmarked mallards in relation to wetland type, social status, and time of day using scan sampling. SruDY AREA The 1,089 km2 study area is located along Colorado's Front Range near Greeley, Colorado. The area is rectangular in shape (36.2 km east to west, 30.5 km north. to south) and is bordered on the west by Interstate Highway 25, on the north by State Highway 392, on the south by State Highway 66, and on the east along the UTM line 542000• Upland habitats are typical of the Colorado Piedmont (Fenneman 1931) portion of the Great Plains physiographic �10 province. Elevations average about 1430 m, with generally flat to rolling terrain interrupted by occasional steep bluffs along major river systems. The study area is drained by 4 rivers: the Cache 1a Poudre, Big Thompson, St. Vrain, and South Platte. Climate is characteristically continental (Gittings 1941), with December, January, and February daily temperatures averaging -1.3, -3.9 and -0.4 C, respectively. Average precipitation during these same months totals 0.74,,0.76 and 0.71 cm. Fog is common during warm winter mornings and evenings. Native grasses consist of blue grama (Boute1oua gracilis) and buffalo grass (Buchloe dactyloides), with rubber rabbitbrush (Chrvsothamnus nauseosus) and snakeweed (Gutierrezia sarothrae) the dominant shrubs. Cottonwood (Populus sargentii), willows (Salix spp.), and green ash (Fraxinus pennsy1vanica) are common along watercourses. Aquatic vegetation varies by wetland type and water regimes. Large wetlands used for irrigation water storage are mostly devoid of vegetation due to extreme water level fluctuations during the growing season. Small wetlands often contain submergent watermilfoi1 (Myriophyllum exa1bescens), pondweeds (Potomogeton spp.), coontail (Ceratophyllum demersum) and muskgrasses (Chara spp.). Smartweeds (Po10gonum spp.), sedges (Carex spp.), cocklebur (Xanthium strumarium), and cattails (Typha spp.) occur around wetland margins and in shallowly flooded areas. Watercress (Nasturtium officiona1e), a common aquatic of warm-water sloughs, harbors high densities of pond snails (Physa spp.) and other macroinvertebrates consumed by mallards. Most land in the study area is devoted to irrigated agriculture or livestock husbandry. Corn, alfalfa, wheat and sugar beets are the dominant irrigated crops. Malting barley and vegetables' are grown in lesser amounts. Several large cattle feedlot operations exist in the northern portion of the area. Winter waterfowl populations typically range from several thousand to >10,000 mallards (Anas platyrhynchos), and up to 10,000 Canada geese (Branta canadensis). Pintails (Anas acuta), green-winged teal (Anas crecca) and wigeon (Anas americana) are present in lesser numbers. METHODS Mallards were captured in Salt Plains bait traps (Szymczak and Corey 1976) on Lonetree Creek, adjacent to Farr Feedlot (in the northwest corner of the study area) on 7 December 1988, and at Chestnut Slough on 8 December 1988 and 11 January 1989. Six birds captured at Lonetree Creek and 30 birds from Chestnut Slough were instrumented with back-mounted radio transmitters (Dwyer 1972) weighing 24g. Mallards marked in December provided information on habitat selection and movements, whereas those marked in January were used primarily to evaluate simulated hunting disturbance. Measurements were made of wing length and body weight, and a standard U.S. Fish and Wildlife Service band affixed to each bird prior to release. Truck-mounted, precision direction finding antennae arrays were used to locate birds from the ground. When a signal was detected, 2 or more azimuths were taken from a known location then plotted on 1:24,000 topographic maps to a resolution of 1 ha. A transparent grid overlay was used to code the location of each bird in the standard UTM grid system. Concurrent with information on the bird's location, the date, time, activity status, air temperature, precipitation, wind speed, wetland name, and habitat type were also recorded. A portable computer (Tandy Model 102) was used to tabulate and �11 error check data in the field. All data were transferred to an IBM-PC for subsequent analyses. Mallards were located as frequently as possible, usually 2-4 times/day. Tracking schedules alternated between (1) locating as many individuals as frequently as possible during the day, and (2) constant monitoring of 1 or 2 individual birds during a single day. Responses of marked birds to hunting disturbance at Chestnut Slough were obtained by continuous monitoring of birds and hunters during the hunting season and recording the reaction of birds during simulated hunts after the hunting season. During the season, personnel arrived at Chestnut prior to arrival of hunting parties in the morning, and remained at the slough as long as hunters and/or marked ducks were present. During this period, activities on Chestnut Slough were categorized by disturbance factors in the following manner: no disturbance (factor 0), shooting audible from Chestnut but not originating on the slough (factor I), shooting on Chestnut >200 m from the subject bird (factor 2), driving near the subject bird (factor 3), walking near the subject bird (factor 4), and shooting <200 m from the subject bird (factor 5). During simulated hunts, shots were fired <200 m from the subject bird(s) and the bird's response recorded. Chestnut was then monitored during duck activity hours to determine when or if the bird returned to the Chestnut roost. All shots were fired over the heads of ducks within legal shooting hours. Wetland availability was determined by monitoring ice conditions of various habitat types daily. Percent open water for each wetland was estimated and recorded along with the date, time, and air temperature. Daily maximum and minimum temperatures and snowfall records were obtained from the u.S. Department of Commerce, Climatological data for the Greeley station. Time budget data were obtained using scan sampling (Altmann 1974) stratified by habitat type and time period. Habitat types were reservoirs, rivers, warm-water wetlands, and other (mostly gravel pits). Time periods were sunrise-0900, 0900-1200, 1200-1500, and l500-sunset. Spotting scopes (40X) or binoculars were used for all time budget collections. Subject animals were selected by pointing the scope or binocular at a flock, then scanning through the flock until 50 individuals were observed. Behaviors were recorded on a tape recorder then immediately transferred to a portable computer. The following behavior classifications were used: (0) out-of-sight, (1) rest, (2) swim, (3) walk, (4) preen, (5) feed in water, (6) feed on land, (7) courtship, (8) aggression, and (9) other. RESULTS Weather and Ice Conditions Temperatures were variable through the 1988-89 winter period, ranging from near average in December, considerably above average in January (+6.3 F), and far below average in February (-9.7 F). Average February temperatures were influenced dramatically by an extreme cold period during the first 10 days of the month (Fig. 1). Precipitation was nearly 0.5 inches above average for all 3 months. The number of days with measurable snow on the ground (Fig. 2) was greater than in 1986-87 and similar to 1987-88 (Ringelman and Szymczak 1988). However, snow cover was divided into 2 segments (Dec and Feb) in 198889 rather than the continuous 50+ day snow cover experienced in 1987-88. Warm January temperatures in 1988-89 kept snow from accumulating even though precipitation was above average. Heavy snow cover in early February corresponded to extreme cold temperatures. �12 60 -U. 50 40 W a: :::l I- <t a: w a.. ~ W --------- ---- -----~-,\ 30 1\ , 20 \ '\ .•.I' , I I , 10 I I 0 I, \, , ,. , \' I' , \, I I \ ,', • rl\",J I ' I, I I I, ,I I "I' '1 ",', , ~ \ , I ----------------~-----------r-;---------------~--------------------1 " -10 \ I "", I \ 'V I', / ' I,' ' " I' I ~ I ' I \ I I \ \ , '1 ~ I ,I II I,I " I' I' I I II I \ : I (\ I J ,,' ,,, \ '" ~ I I- \ i , , - ,\ \ \ \ \ \ -- ----1------------------------ I , I \ I I I , I t» ~I , '''v -20 1 10 20 30 Dec. 10 20 30 DATE 10 Feb. 20 Fig. 1. Dally maximum and minimum temperatures at Greeley Colorado, 1988-89. Z ~ 10 8 c Z :::l o 6 a: CJ z o ~ o 4 2 Z til o 1 10 20 Dec. 30 10 20 DATE Fig. 2. Snow on ground at Greeley, Colorado, 1988-89. 30 10 20 Feb. 28 �13 Ice conditions of rivers varied seasonally and between areas. Except during early February, some river habitat was available in the study area throughout winter (Fig. 3). The Cache 1a Poudre River, on a percentage basis, provided less open water than the Big Thompson or the South Platte. The South Platte remained ice-free in most of the study area throughout the field season. Most reservoirs froze in mid-December and remained frozen except for small open water areas in the middle of some reservoirs that were maintained by the activity of roosting waterfowl (Fig. 3). Most small ponds remained frozen. The January warm period had a slight influence on the amount of open water on some reservoirs, but had a more pronounced affect on ponds (Fig. 3). Characteristics of Instrumented Birds Of the 25 mallards radio-marked during December, 7 were adult males, 5 were adult females, 7 were immature males, and 6 were immature females (Table 1). The initial sample of marked birds was intentionally skewed, since males experience higher hunting season mortality rates than females. By 10 January, only 10 radio-marked birds remained in the study area. Eight radios had been recovered from birds that had been shot or had died from natural causes (Table 1). When traps were re-dep10yed on Chestnut Slough on 11 January, an additional 4 adult male, 3 adult female, 2 immature male, and 2 immature female mallards were radio-marked. Movements Instrumented ducks were re-10cated 1,159 times, with the time of telemetry fixes nearly equally distributed throughout the day (Table 2). Thirty-eight percent (446) of the telemetry locations were obtained in December, 39% (452) were recorded in January, and 23% (260) were collected in February. Radio-marked birds remained concentrated near Chestnut Slough and Lonetree Creek, the two capture sites (Fig. 4). Despite this apparent affinity for wetlands in the vicinity of the capture sites, many birds used both areas (Figs. 5-33). Radio-marked mallards were also located along and near the South Platte River near Kersey and Gilcrest, on the Cache 1a Poudre River near Windsor, the Big Thompson River southwest of Greeley, and warmwater sloughs near Platteville (Fig. 4). Overall, home ranges were smaller in 1988-89 than in 1986-87 or 1987-88 (Table 3). Home range sizes for 1988-89, computed using either the minimum area polygon method or the Jennrich and Turner confidence ellipse, did not differ according to bird age, sex, or age/sex interaction (P-0.37, Table 4). Minimum area home ranges (± SD) were 143.2 km2 (± 181.5) for adult females, 76.4 krn2 (± 95.5) for adult males, 49.3 km2 (± 34.5) for immature females, and 45.0 km2 (± 53.7) for immature males. The total number of locations per bird did not correlate with either the minimum area home range (r-0.09, p-0.63) or the Jennrich-Turner 95% confidence ellipse (r--0.11, p-O.57), suggesting that the number of telemetry locations was sufficient to provide a stable estimate of home range size. �14 100 80 60 40 RNERS 20 0 a: W 100 I~ 3: z w 80 60 RESERVOIRS 0- 0 IZ w a: w Q. 40 20 0 :.......................... :", 0 -0 0 :" ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 100 80 ,\ 60 i'" , I\ \ I \ 40 I 20 PONDS 1 1\ I / / /' \ \ \ '10 / \,." \/ 0 /' r--' 20 30 DEC / \ ,. \,. ,. ", , " \/ \ .•.. ,. 10 20 30 JAN DATE Fig. 3. Percent open water during 1988-89 for 3 wetland types. - ,. ...•• - - -" 10 FEB 20 �15 Table 1. Characteristics of radio-marked mallards during 1988-89. Capture location Lonetree Lonetree Lonetree Lonetree Lonetree Lonetree Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Chestnut Date of capture Crk. Crk. Crk. Crk. Crk. Crk. 7 7 7 7 7 7 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 11 11 11 11 11 11 11 11 11 11 11 Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Dec Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Bird number Age Sex 1384 1400 1420 1448 1480 1500 1360 1530 1560 1590 1630 1650 1670 1690 1708 1730 1778 1800 1824 1850 1906 1927 1940 1960 1980 048 220 266 281 532 2420 2560 2590 2650 2670 2927 Adult Immature Adult Immature Adult Immature Adult Immature Immature Immature Adult Immature Immature Adult Immature Immature Adult Adult Adult Adult Adult Immature Immature Immature Adult Adult Immature Adult Adult Adult Immature Immature Immature Adult Adult Adult Male Male Male Female Female Female Male Female Female Female Female Male Male Male Male Male Female Male Male Female Female Male Male Female Male Female Male Male Female Male Male Female Female Male Female Male Fate Last contact 15 Feb Died 10 Feb Died 3 Jan No contact Last contact 22 Jan Died 20 Jan Died 22 Jan Last contact 11 Feb Shot 17 Dec Shot 23 Dec Died 14 Jan Shot 17 Dec Radio removed 29 Dec Last contact 20 Feb Shot 28 Dec Died 16 Dec Last contact 24 Dec Last contact 21 Dec Last contact 22 Dec Last contact 22 Jan Last contact 26 Dec Shot 27 Dec Died 1 Feb Last contact 27 Dec No contact Last contact 5 Feb Last contact 20 Feb Last contact 11 Feb Last contact 16 Feb Last contact 15 Feb Died 3 Feb Last contact 18 Jan Died 9 Feb Last contact 11 Feb Last contact 20 Feb Died 11 Feb �16 Table 2. Hourly distribution of telemetry locations during 1988-89. Time interval 0400-0459 0500-0559 0600-0659 0700-0759 0800-0859 0900-0959 1000-1059 1100-1159 1200-1259 1300-1359 1400-1459 1500-1559 1600-1659 1700-1759 1800-1859 Frequency Percent Cumulative frequency 1 21 95 126 88 95 75 94 80 74 76 87 98 127 22 0.1 1.8 8.2 10.9 7.6 8.2 6.5 8.1 6.9 6.4 6.6 7.5 8.5 11.0 1.9 1 22 117 243 331 426 501 595 675 749 825 912 1010 1137 1159 Cumulative percent 0.1 1.9 10.1 21.0 28.6 36.8 43.2 51.3 58.2 64.6 71.2 78.7 87.1 98.1 100.0 Table 3. Comparative mean home range sizes for radio-marked mallards during winter. 2 Home range size (km ) Year No. fixes Minimum area polygon method Jennrich-Turner method (95% ellipse) 1986-87 1,388 150.2 340.2 1987-88 1,406 124.0 232.6 1988-89 1,159 83.8 159.5 Habitat Use As in previous years, birds used warm-water wetlands and rivers extensively but made infrequent use of ponds and reservoirs, most of which remained frozen during winter (Table 5). Seven of 34 birds used cattle feedlots, particularly during cold weather. Females of both ages used warmwater wetlands less than males (8.1% of female locations versus 18.0% of male locations). Except for an apparent increase in use of riverine habitat with declining temperatures, habitat use during 1988-89 did not correlate with weather variables. �Windsor + D 0 + 0 ~ ~~~ +. Greeley 0 + ++ Ii 0 Q +f" +'Iir v ~ c:::;:> . _~ $'~.IIIIIIIm~,?IF ~ ci) ,:7 laIhamRes . ~ 0 J+~ SIou!jl 0 ~ 0 ~ n.: ~~ + ...".._.:,~- C> o~ c, ~ sf ;.l \\/.._ II " ",'VI) rzzzzzt,?z~~zzzn 1M Platteville Fig. 4. Locations of all radio-marked mallards, 1988-89. D Milton Res. •.... -...I �18 o D o o o = 10 km I Z 2 2 2 2 Z 2 2 2 II Fig. 5. Locations of adult female 048, 11 Jan to 5 Feb, 1989. c o = "\,0 10 km kZlllZZZIZI Fig. 6. Locations of adult female 281, 11 Jan to 16 Feb, 1989. �19 ..................................... ........... ~ o <:0 ..... .... ... ....... ... ...... ... 10 km e 7 7 7 7 7 7 7 7, 21 Fig. 7. Locations of adult female 1480, 7 Dec to 22 Jan, 1989. ,. o o 10 km Fig. 8. Locations of adult female 1630, 8 Dec to 14 Jan, 1989. ::;... 1" : �20 o ,. o ~ l \ . . o ..~. .•. :1> = o 10 km eZZZZ27ZZZI Fig. 9. Locations for adult female 1778, 8 Oec to 24 Oec 1988. o o D ......'" ;'il o ... 0 = .. .. .. ·0 ' .. '\. ' ' o .~ .9° 10 km tl121lZlZZI Fig. 10. Locations for adult female 1850,8 Dec to 22 Jan, 1989. �21 , o -, ". ". ,. .~. ,. <::> o .~ • <;>0 10 km e Z 7 Z 7 7 Z 2 2 2. Fig. 11. Locations of adult female 1906, 8 Dec to 26 Dec, 1988. �22 <::> o 10 km elll?IIIZZI Fig. 13. Locations of adult male 266, 11 Jan to 11 Feb, 1989. o D ................... ~ ·..············ ..···············0········ "\. o 10 km t . Z ? ? ? 2 Z 2 2 21 6 Fig. 14. Locations of adult male 532, 11 Jan to 15 Feb, 1989. �23 o ,. o o '. +" ++ = o 10 km ., 2 Fig. 15. Locations of adult male 1360,8 ? 2 2 ? ? Z ? d D Dec to 22 Jan, 1989. ,. o D Fig. 16. Locations of adult male 1384, 7 Dec to 15 Feb, 1989. �24 = o .~ ....• 10 km eZZZZ2Z222i Fig. 17. Locations of adult male 1420,7 Dec to 3 Jan, 1989. ,. D o -, -, o -, II o ... -, .... 0.. -, -, ,. .,. = o .~ ..... 10 km '2 ? 2 2 2 ? ? ? 2 A Fig. 18. Locations of adult male 1690,8 Dec to 20 Feb, 1989. �25 ,. o o .~ ,.•. 10 km e 2 2 2 2 2 2 2 ? 21 Fig. 19. Locations of adult male 1800,8 Dec to 21 Dec, 1989. 0 /I .., .> = 7 " ~ cJ 0 e "'- •• .~ 0 o~ 6 ~/~ .•. , 10 km i?2Z????ZZd U Fig. 20. Locations of adult male 1824,8 Dec to 22 Dec, 1989. �26 ,. ~ 0 1I .•. ..,. c: J Q 0 0 ~o o~ C> ~f~ .~ .9' U 10 km rz z z z z z z Z Z ZI Fig. 21. Locations of adult male 2650, 11 Jan to 11 Feb, 1989. "'" o e 10 km It ? ? ? Z Z 2 2 2 A Fig. 22. Locations of adult mate 2927, 11 Jan to 11 Feb, 1989. c �27 o = 0° .0· .0· o o .~ •••• 10 km e Z ? 2 Z 2 2 2 Z 21 Fig. 23. Locations of Immature female 1500,7 Oec to 20 Jan, 1989. ~ = .:: ~···~····· ...: ..·:o:·:·::::~ .... .... .~ •••• 10 km ., ? Z Z 2 ? Z 2 Z a Fig. 24. Locations of Immature female 1530,8 Oec to 11 Feb, 1989. �28 , I) o 't... .... ,.: . ........ = '0 ". '" '" ". '" '" ". '" ". ". '" '0. • ..... :"t:;; 0"" 10 km e 2 ? Z ? 2 Z Z Z 21 Fig. 25. Locations of Immature female 1590, 8 Dec to 23 Dec, 1988. o () o o .. .... 7····.... ..' .... ./\ . 0 ~ = .. .. ' .. ' c ' .~ 0"" 10 km 12 Z Z Z 2 ? 7 Fig. 26. Locations of Immature female 1960,8 7 7 A Dec to 27 Dec, 1988. �29 ~ o () 4 0 0 .. 7 .., GJ <::> 0 10 km vI? ? 2 Z Z Z ? 21 Fig. 27. Locations of Immature female 2560, 11 Jan to 18 Jan, 1989. ~ o <::> o .~ .9' 10 km Fig. 28. Locations of Immature male 220, 11 Jan to 20 Feb, 1989. �30 o D o /I = o .~ .,,' 10 km eZ?22????" Fig. 29. Locations of Immature male 1400,7 Dec to 10 Feb, 1989. ,. 0 /I .., • 7 ~ GJ = 0 ...•.. 0 O~ Co ~f~" .~ .", 10 km 17 7 7 Z Z Z Z Z 7 d U Fig. 30. Locations of Immature male 1670,8 Dec to 29 Dec, 1989. �31 ,. 0 II • Q 0 e .~ .9' 0 "\. ~/~ ¥. o~ Co U 10 km 12 2 :2 Z Z Z Z Z Z 21 Fig. 31. Locations of Immature male 1708, 8 Dec to 28 Dec, 1988. 0 •. II .., ~ GJ = 0 e .~ .9' 0 "\. O~ Co ~f~ 10 km Ii 2 ? ? Z Z 2 Z ? A U Fig. 32. Locations of Immature male 1730,8 Dec to 16 Dec, 1988. �32 o o o .~ 0"" 10 km Q21?2??ZZZi D Fig. 33. Location. of Immature male 1940,8 Dec to 1 Feb, 1989. �33 Table 4. 1988-89. Home range sizes of radio-marked mallards during winter, 2 Home range size (km ) Bird No. 048 220 266 281 532 1360 1384 1400 1420 1480 1500 1530 1590 1630 1670 1690 1708 1778 1800 1824 1850 1906 1940 1960 2420 2560 2650 2670 2927 Means No. fixes Minimum area polygon method Jennrich-Turner method (95% ellipse) 12 44 55 25 25 33 25 129 14 33 15 12 14 20 11 142 28 18 17 15 22 21 61 36 25 10 52 51 61 17.6 54.6 4.0 81.8 37.0 226.8 257.2 129.2 19.4 454.5 36.2 32.9 99.5 24.9 3.8 118.4 20.5 29.8 10.1 0.7 414.7 69.7 4.4 72.4 67.4 0.1 83.7 53.1 6.6 67.0 129.7 8.2 196.0 82.3 476.8 668.1 96.3 62.7 774.9 83.8 160.1 193.6 94.4 14.4 76.4 23.6 118.6 36.1 2.4 629.8 136.5 7.8 153.3 163.3 0.3 112.2 48.7 8.1 83.8 159.5 �34 Table 5. Habitat use by individual radio-marked mallards, 1988-89. Percentage of locations by habitat typea Bird No. Unk. Pond Lake Hold. Warm-W. Ditch River Corn. Feed. No. obs. 048 26.7 0 0 0 60.0 6.7 6.7 0 0 15 220 10.0 4.0 0 0 44.0 10.0 24.0 0 8.0 50 266 6.8 0 0 0 62.7 1.7 28.8 0 0 59 281 10.7 0 0 0 50.0 7.1 28.6 0 3.6 28 532 0 20.0 0 0 28.0 8.0 32.0 4.0 8.0 25 1360 3.0 6.1 33.3 0 30.3 3.0 12.1 9.1 3.0 33 1384 21.9 9.4 0 0 34.4 6.2 21.9 6.2 0 32 1400 8.5 2.1 2.8 2.8 52.5 4.3 26.2 0.7 0 141 1420 0 0 7.1 0 50.0 0 42.9 0 0 14 1480 8.3 5.6 0 2.8 63.9 2.8 8.3 8.3 0 36 1500 0 0 0 0 73.3 0 26..7 0 0 15 1530 20.0 26.7 6.7 0 26.7 13.3 0 6.7 0 15 1560 50.0 0 0 0 25.0 0 25.0 0 0 4 1590 7.1 3.6 3.6 0 64.3 10.7 10.7 0 0 28 1630 8.3 0 0 0 58.3 25.0 8.3 0 0 24 1650 0 0 0 0 60.0 0 40.0 0 0 5 1670 8.3 0 0 0 83.3 8.3 0 0 0 12 1690 5.2 0 2.6 0 51.6 5.2 32.3 3.2 0 155 1708 6.7 0 6.7 0 60.0 10.0 13.3 3.3 0 30 1730 30.0 0 0 0 40.0 20.0 10.0 0 0 10 1778 5.0 5.0 30.0 0 45.0 5.0 0 10.0 0 20 �35 Table 5 (cont.). Percentage of locations by habitat typea Bird No. Unk. Pond Lake Hold. Warm-W. Ditch River Corn. Feed. No. obs. 1800 10.5 10.5 15.8 o 47.4 o 10.5 0 5.3 19 1824 21.1 0 0 o 36.8 31.6 o 5.3 5.3 19 7.4 7.4 o 63.0 o 11.1 0 o 27 o 23 1850 11.1 1906 8.7 0 0 o 60.9 o 21.7 1927 25.0 0 0 o 50.0 o 25.0 0 o 4 1940 6.2 0 0 o 40.6 3.1 50.0 0 o 64 1960 12.2 0 0 o 75.6 2.4 9.8 0 o 41 2420 0 0 0 o 56.0 4.0 40.0 0 o 25 2560 0 0 0 o 100.0 o o 0 o 10 2590 0 0 0 o 83.3 16.7 o 0 o 6 2650 5.6 1.9 0 o 72.2 o 18.5 1.9 o 54 2670 3.8 0 0 o 13.2 18.9 50.9 1. 9 11.3 53 2927 0 0 0 o 60.3 4.8 33.3 1. 6 o 63 Means 10.0 3.0 3.4 0.2 53.6 6.7 19.8 2.0 1.3 34 4.3 a Key to habitat abbreviations: Unk. - unknown habitat type Pond - Small ponds/reservoirs; Lake - lakes; Hold. - holding/sewage ponds; Warm-W. - warm-water wetlands; Ditch - ditches; River - rivers; Corn. - cornfields; Feed. - feedlots. Response to Hunter Disturbance Responses to disturbance were recorded for 14 radio-marked birds at Chestnut Sloughs during the final portion of the 1988-89 duck hunting season (Tables 6 and 7). Thirteen of these birds had been marked at Chestnut and one at Lonetree Creek. Eleven of the Chestnut-marked birds (3 of 5 AM, 4 of 4 AF, 3 of 6 1M, 2 of 4 IF) were present at Chestnut either during mid-morning hours on 16 December, the day before the hunting season, or prior to sunrise on 17 December, probably indicating the birds had been using the area on a regular basis since they were marked on 8 December. �36 TabLe 6. Presence or absence of radio-marked birds at Chestnut SLough, by day, during and (P = Present, BLank = Absent) foLLowing disturbance 1988-89. Date December Age/Sex AM AF 1M IF Bird No. 16 1690 1800 1824 1630 1778 1850 1906 17 18 19 20a P P P pb P P p p P P p pb p p 1590 1960 P P P 23 24 25 26 pb 27a 28 P P 29 30a 31 P P P 2 pb P P P 1400c 1650 1670 1708 1940 21a 22 Jan. pb pb p P P P pb pB P P P p P a No disturbance on Chestnut. b Departed without or prior to any disturbance on that date. c Radio-marked on lonetree Creek. p �37 Table 7 . Age/Sex AM Hunting season disturbance factors (see methods), bird reaction, and roost homing for radio-marked birds at Chestnut Sloughs 1988-89. Bird No. 1690 1800 Disturbance 1 2 3 4 5 10 2 * 1630 12/16 * 1778 12/16 12/17 *13 1906 1400 12/16 12/17 12/19 12/22 12/28 12/?8 12/29 12/30 12/31 1/2 1/2 1650 12/17 1670 12/16 12/17 12/19 1708 12/20 12/21 12/22 1 1* 3 2 2 2* 10 1 12/17 12/22 12/16 12/17 12/17 3 * * * 1850 1M 12/18 12/19 12/20 12/26 12/27 12/28 0 12/17 12/19 1824 AF Date 1 10 0 94 Did not return 4 22 Did not return 1 3* 1 1 15 24 21 Did not return 2 4 1* 22 (Did not depart) 10 3 0 >384~792 2 4 * 7* 1 2 1* * * * 9* 2 1 2* 1* 1* 10 * * 648 1* 6 * * 7 125 9 34 Did not return 1 1 2 10 (Did not depart) 30 0 0 0 (Did not depart) 16 19 4 2 1 5 1 1 Hours before return 1* 1 4 16 Accumulated rating before departure 1 2 22 (Did not dap ar t.) 31 >24~44 0 >48~60 0 Did not return 9 0 29 5 (Did not depart) 9 10 4 1 3 2 9 3 5 1* 19 Harvested12/17 >8~19 1* 22 0 5 4 41 Did not return (Radio removed 12/29) 0 (Did not depart) 0 18 0 Did not return �38 Table 7. Age/Sex (Continued) 1940 1M 1590 IF 1960 * Indicates Table 8. Disturbance Bird No. a Date 12/16 12/17 12/21 1 2 * 18 * 8 3 4 2 12/16 12/17 12/18 12/19 1 * 8 7 4* 1 * 18 * * type of disturbance 4 1 1986-87 1987-88 1 2* 8 4 1 1 Hours before return 22 (Did not depart) 43 which occurred Did not return 11 22 4 16 22 3 25 Harvested12/23 22 (Did not depart) 43 1 a .48~67 just prior Did not return to bird departure. A summary of the response to disturbance of radio-marked Chestnut Sloughs during the hunting season. See methods explanation of disturbance categories. Stay (%) Leave (%) Total Stay (%) Leave(%) Total 300 (96.9) 10 (3.1) 322 and res120nse to disturbance 2 1 Response 3 35 (89.7) 20 (69.0) ~ (10.3) ...2. (31.0) 39 29 12 (100.0) 15 (100.0) __Q __Q 12 15 94 a a No. of occurrances Year Accumulated rating before departure 1* 2 2 12/16 12/17 12/17 12/20 5 4 birds on for factor: 5 a a Q 1 (100.0) a 1 7 (63.6) 13 (71.2) 8 (88.9) ~ (36.4) ...l (18.8) 1 (11.1) 16 11 9 1988-89 Stay (%) Leave (%) Total 127 (100.0) 49 (96.1) 21 (95.5) 34 (82.9) 9 (60.0) _1 (0.7) (3.9) _l (4.5) ...2 (17.1) _j_ (40.0) 128 51 41 22 15 All Stay (%) Leave (%) Total .u Years .z 439 (97.6) 99 (94.3) 48 (77.4) (2.4) _6 (5.7) 14 (22.6) 462 105 62 47 (82.5) 17 (68.0) (32.0) 10 (17.5) 57 25 .a �39 Eight birds were subject to m1n1mum harassment on 16 December (Table 6) when some walking and driving (Table 7) occurred on Chestnut. Three birds did not depart in response to driving or walking, and of the 5 that did depart only one did not return. All others returned to Chestnut to roost. Of the 10 birds on Chestnut on opening day (17 December), only one (1670) departed prior to any disturbance (Table 6). Most others tolerated a considerable amount of disturbance in terms of shooting away from Chestnut. Four of the remaining 7 tolerated shots fired within 200 m, but all eventually left the area. Only one bird (1590) returned to Chestnut on the evening of 17 December, and 3 of the birds did not return to Chestnut for the remainder of the hunting season. After 17 December, 10 of the original 13 birds returned to Chestnut at some time, but most visits were brief. Before the second weekend of the hunting season, all but one bird had discontinued the use of Chestnut (Table 6). The birds did not return even though very cold temperatures toward the end of the month (Fig. 1) reduced the number of open water roosts in the study area. As in previous years, birds generally did not respond· to shots fired from areas adjacent to the Chestnut property. Responses to other disturbance factors (Table 8) have varied considerably between years and have been most likely confounded by the influence of weather and the effect of accumulative disturbance. Future analysis will weigh the effects of these other variables. It is clear that birds will leave Chestnut and move to other wetlands during the hunting season without being disturbed. Of 104 radio-marked bird departures from Chestnut during the hunting season after the 3 year period, 32% occurred without any prior disturbance on that particular day, and additional 21% were not direct responses to harassment (Table 9). Table 9. Comparison of the number of radio-marked bird departures initiated without disturbance with those immediately following some type of disturbance. See methods for description of disturbance categories. Disturbance 1986-87 No disturbance at all Number of de~artures 1988-89 1987-88 All Years 4 16 13 33 Some disturbance, but not preceding departure 12 3 7 22 Disturbance prior to departure (categories 1-5) 24 8 17 49 40 27 37 104 Total �40 Response to Simulated Hunting Disturbance When simulated hunting disturbance began on 25 January, 3 ducks marked on 11 January and 2 birds marked on December 7-8 remained on Chestnut Slough. Shots fired at sunrise were the primary disturbance factor used during simulated hunting, but sometimes birds flushed from the investigator walking just prior to the shot being fired. Only 2 shots were fired in the afternoon. On many occasions birds left Chestnut prior to sunrise with no disturbance (Table 10), even during the extreme cold experienced during the test period. Of 45 radio-bird day occurrences on Chestnut, birds remained on Chestnut on 6 occasions, and departed prior to disturbance 22 times. On 5 of 6 occasions, birds remaining on Chestnut experienced 1 shot greater than 200 m away, while a shot was fired in the afternoon near the sixth bird. Usually a shot fired near the bird stimulated departure from Chestnut. Once leaving, the Chestnut roost birds did not return to Chestnut during the daylight hours. They did fairly consistently return to roost at night 10 to 13 hours after leaving. The rate at which birds returned to roost the first night was independent of whether the bird left in response to disturbance or not (x2 - 1.50, P > 0.10). However, on the 3 occasions that birds were shot at multiple times before departing, the birds abandoned Chestnut for an extended period (Table 10). Table 10. Simulated hunting disturbance, bird reaction, and roost homing for radio-marked birds at Chestnut Slough, post-hunting season, 1989. Disturbance Facto! At De12arture AgeLSex AM Bird # Date 266 1/25 1/27 1/29 1/30 1/31 2/1 2/2 2/3 1690 1/25 1/26 1/27 1/28 1/29 1/30 1/31 2/1 2/2 2/12 2/13 0 *a * * * * * * * * 2 * * 1* * * * 1 Hours Acc. Rating Tem12 F before return 0 30 34 0 16 28 0 2 10 5 17 10 1* 0 37 11 0 13 11 0 12 -4 0 Did not return -14 0 30 10 15 5 10 1* 0 16 10 0 25 10 2 (Did not 2b depart) 17 <8 2 11 0 37 13 11 5 1* 227 10 -4 2* 30 13 5 1* 20 0 12 5 �41 Table 10 (cont.). D;LstuIbance Eactor At De~aIture Age/Sex Bird # 2650 AM 2650 Date 1/25 1/26 AF 1M 281 220 1/28 1/29 * 1400 1M a b c d 1400 2/1 1/31 2/1 2/2 1/25 1/26 1/27 1/28 1/30 1/31 2/1 2/2 5 1* * 1/25 1/26 1/27 1/29 2 1 1/27 1/30 1/31 2/1 2/2 2/5 2927 0 1 1 1 * 1* 1* 3* 1* 1 * 1*c * 1c * 2* Acc. Rating Temp F 5 30 2 (Did not lOb depart) 5 16 0 25 2 (Did not 2 depart) 2 17 " 0 37 5 11 5 -4 15 -27 5 2 0 5 0 5 0 10 " 30· lOb 16 30 " 13 40 13 -4 1* 0 5 0 0 0 0 5 30 15 16 25 17 37 13 1* 5 -4 * 1* * * * * Hours before return 10 10 10 11 10 34 Did not return 10 34 Did not return " 10 Did not return 11 9 9 -34 11 11 11 Did not returnd Indicates disturbance factor associated with departure from Chestnut Minimum temperature on that date (Greeley NOAA) Disturbance in the afternoon Died on 2/10/89 �42 Behavior Thirty-two scan samples were used to catagorize the behavior of 1,600 ducks during winter 1988-89 (Fig. 34). As in previous years, resting and swiming were the predominate behaviors. The quantity of behavior data collected during 198889 were insufficient to examine for differences by habitat type, sex or age. - SWIM REST OTHER LAND FEED WALK PREEN WATER FEED Fig. 34. Behavioral time budget of wintering mallards, 1988-89. �43 DISCUSSION Subtle changes in habitat availability and management may have been responsible for the small home range sizes observed in 1988-89 compared to previous years. The property manager and hunters at Chestnut Slough made efforts to reduce needless disturbance to ducks, with apparent success. Telemetry locations were clustered around Chestnut and the adjoining South Platte River more than in previous years, suggesting that habitat requirements could be met within this local area. This effectively reduced the home range size of many instrumented birds. Additionally, no use was made of Milton Reservoir and the Beebe Draw region just north of Milton, and little use waS made of Latham Reservoir. Because these lakes are located along the eastern edge of the study area, avoidance of these wetlands reduces travel distances and associated home range size. Relative to their availability (0.6% of the surface water area), warm-water wetlands were once again highly selected by radio-marked mallards in 1988-89. As noted by other researchers, these wetlands provide food resources and thermal refugia for waterfowl during winter. Mallards respond to a hierarchy of habitat selection that, at its highest levels, is dependent upon the availability of ice-free wetlands weighted by such disturbance factors as hunting (Ringelman et al. 1989). When weather allows, mallards prefer lakes and small ponds over rivers, holding ponds and ditches. Under snowfree conditions, ducks prefer to feed in cornfields rather than feedlots. However, mallards showed plasticity in their response to these and other conditions, adapting their movements and behavior to short-term weather events. Temporal and spatial variability in habitat use also relate to social events that occur during winter. Most mallards establish pair bonds during midwinter in Colorado, and wetlands such as lakes and warm-water sloughs are thought to provide "courtship arenas" for mallards on the High Plains (Ringelman et al. 1989). After pairing, mallards vacate such wetlands in favor of locations that provide greater isolation from conspecifics. LITERATURE CITED Altmann, J. 1974. Observational study of behavior: sampling methods. Behaviour 49:227-267. Dwyer, T. J. 1972. an adjustable radio-package for ducks. Bird-banding 43:282-284. Fenneman, N. M. 1931. Physiography of the western United States. Book Company, New York and London. 534pp. McGraw-Hill Gittings, E. B. 1941. Climate of Colorado. Pages 798-808 in Yearbook of Agriculture: Climate and Man. U.S. Dep. Agric., Washington, D.C. Ringelman, J. K., W. R. Eddleman, and H. W. Miller. 1989. High plains reservoirs and sloughs. Pages in L. M. Smith, R. L. Pederson, and R. M. Kaminski, eds. Habitat management for migrating and wintering waterfowl in North America. Texas Tech Press, Lubbock. �44 LITERATURE CITED (cont.) Ringelman, J. K., and M. R. Szymczak. 1988. Habitat use by mallards along the Front Range of Colorado. Job Progress Report Project 01-03-212, Colorado Division of Wildlife, Fort Collins, Colorado. Szymczak, M. R. , and J. F. Corey. 1976. Salt Plains duck trap in Colorado. Prepared by: ~ j(. ~ James K. Ringelman Wildlife Researcher C Construction and use of the W 71J;,£JP Michael R. Szymczak Wildlife Researcher C �45 Colorado Division of Wildlife Wildlife Research Report October 1989 JOB PROGRESS REPORT State of __~C~o~l~o~r~a~d~o~~ Project Work Plan _ Migratory Game Bird Research 01-03-212 1 : Job 18 Job Title: Winter survival and reproductive success of female mallards Period Covered: Authors: 01 April 1988 through 31 March 1989 Clinton W. Jeske, James K. Ringe1man. and Michael R. Szymczak Personnel: D. Anderson, J. Corey, D. Gilbert, M. Gilbert, M. Miller, Colorado Cooperative Fish and Wildlife Research Unit; M. Albrecht, A. Archuleta, C. Jeske, J. Laake, E. Rexstad, R. Scarpe1la, D. Smith, K. Trust, K. Wilson, Colorado State University; J. Corey, D. Freddy, R. Hopper, K. Navo, J. Ringelman, M. Szymczak, Colorado Division of Wildlife; M. Nail, R. Schneiderbeck, U.S. Fish and Wildlife Service. ABSTRACT Mallards were captured on the Monte Vista National Wildlife Refuge during 12-13 December, 12-17 January, 9-10 February, and 27 February-2 March. Age, sex, and condition index data were obtained for each bird. Monel wing bands were affixed to mallards captured in January, and 54 adult female mallards were radio-marked with neck collar transmitters in March. In addition to monitoring behavior and mortality of instrumented ducks, systematic carcass searches were conducted throughout the winter to provide samples used to examine (1) differential mortality rates based on age, sex and condition (determined from wing bands), (2) percentage of carcasses with indications of starvation, (3) percentage of carcasses showing traces of lead poisoning, and (4) percentage of carcasses testing positive for avian cholera. Within each age-sex class, mean body weights differed little among banding periods. However, individual birds recaptured during subsequent trapping periods lost weight. Mallards tended to get their bills caught in the flexible neck collars originally used for radio attachment; 67% of the radios were recovered within a month. Subsequent collar designs proved better, but only 3 instrumented females remained alive by the May nesting period. Of the 1,677 carcass remains (wings) collected, 131 were from banded birds. Most remains were of adult males (40%), followed by adult females (28%) and immatures (16% each sex). Banded birds found dead did not differ in condition from the sample of birds at banding, but starvation was the cause of death among 24% of the banded birds compared to 7% of the unbanded ducks. Aerial counts from color slides taken on 4, 11 and 18 January indicated an average population of 24,340 birds. Since only about one-third of the existing carcasses were detected by search crews, the 1,677 wings recovered by search crews extrapolates to an estimated 4,736 dead birds, or about 20% of the January population. Avian cholera and predation were the principal causes of mallard mortality. ��47 VINTER SURVIVAL AND REPRODUCTIVE SUCCESS OF FEMALE MALLARDS Clinton W. Jeske James K. Ringelman Michael R. Szymczak P. N. OBJECTIVES 1. Quantify winter survival rates of adult female mallards in poor and good condition. 2. Determine the sources of winter mortality for mallards in the San Luis Valley. 3. Investigate the relationship between winter body condition and reproductive performance of mallards wintering in the San Luis Valley. 4. Measure the winter energy balance of mallards by quantifying components of energy acquisition and depletion. SEGMENT OBJECTIVES 1. Capture and radio-mark 80 adult female mallards during the second week of January. After estimating the distribution of condition indices for the population, affix radios to 40 birds in the upper one-third and 40 radios to birds in the lower one-third of the condition distribution. 2. Mark a minimum of 1,000 mallards (250 of each age and sex) with wing bands and U.S. Fish and Wildlife Service leg bands. 3. Monitor radio-marked ducks by vehicle and aerial tracking throughout the January-March period. Document movements and status (alive, dead, paired, unpaired) of all birds. Attempt to ascertain the cause of mortality. 4. Conduct systematic surveys to obtain carcass remains (wings) of dead mallards. Evaluate wings for (1) wing bone fat, Pasturella bacteria, and lead in the wing bone, and (2) the presence or absence of wing bands. 5. Estimate winter mortality rates with maximum-likelihood procedures using competing risks theory to account for radio-marked birds whose fate is unknown. 6. Conduct respirometry experiments to determine the lower critical temperature and basal metabolic rates of winter-acclimated mallards. 7. During April-June, locate radio-marked mallards during nesting and obtain information on reproductive performance. Measurements will include egg mass, egg dimensions and number, total clutch mass, fertility(hatching success, nesting success, and renesting frequency. Relate reproductive performance to mid-winter body condition. �48 8. Quantify the nutritional value of barley through (1) digestabili ty experiments with penned ducks, and (2) periodic sampling of barley fields to evaluate losses in food value as a result of weather-induced nutrient leaching. STUDY AREA This study was conducted in the San Luis Valley (SLV), located in south-central Colorado. The SLV is a 12,960 km2 intermountain basin, bounded by the San Juan Mountains to the west and the Sangre de Cristo Range to the east. As a result of the surrounding mountains and 2,286 to 2,438 m elevation, January temperatures average -4 C, and snow and ice fog are common. Upland areas are dominated by greasewood (Sarcobatus vermicu1atis) and rabbitbrush (Chrysothamnus spp. ). Common wetland vegetation includes baltic rush (Juncus balticus), cattail (Typha 1atifo1ia), hardstem bulrush (Scirpus acutus), coontail (Ceratophyllum demersum) and pondweeds (Potamogeton spp.). Further descriptions of the SLV can be found in Hopper et al. (1975) and Szymczak (1986). An average of 14,700 mallards winter in the SLV (1982-84 average, Colo. Div. Wi1d1., unpubl. data), with most residing on the Monte Vista National Wildlife Refuge (MVNWR). MVNWR is 5,670 ha in area and has over 200 ponds and impoundments. Wintering ducks are concentrated on those water areas which do not freeze as a result of continuous pumping or artesian flow. Mallards breed throughout the SLV and surrounding mountains (Rutherford and Hayes 1976, Szymczak 1986), but nesting is concentrated on the MVNWR (pers. obs.). METHODS Weight Changes of Marked and Unmarked Mallards Mallards wintering on the Monte Vista National Wildlife Refuge (MVmlR) were captured with Salt Plains bait traps (Szymczak and Corey 1976) and cannon nets (Dill and Thornberry 1950) from 12-13 December 1988, 12-17 January, 9 -10 February, and 27 February-2 March 1989. Data on age, sex, weight, and wing length were obtained for all birds, and a condition index (Ringe1man and Szymczak 1985) calculated for each. All mallards were banded with standard USFWS leg bands. During the January trapping period, most mallards also had monel bands affixed to the shaft of primary_feather VIII of both wings. Mean weights were plotted by trapping period for each age-sex class. The UNIVARIATE Procedure (SAS Institute 1985) was used to test normality of weight and condition index distributions by age-sex class. Duncan's mu.lt Lp Le range test was used to compare weight and condition index means by trapping period and agesex class. To examine the relationship between weights and trapping method, weights of birds captured in cannon nets during the 9-10 February trapping period were compared with weights of birds captured in bait traps during that same period. Mean weights of birds recaptured within a banding period, as well as mean weight differences of birds recaptured during subsequent trapping periods, were compared with Duncan's Multiple Range test. Weights and condition indices of mallards originally captured in 1987 and 1988 and recaptured in 1989 were examined to see if a bird in relatively "good" or "poor" condition remains in that relative weight or condition class in subsequent years. Weight and condition indices were corrected for different mean condition values between years by subtracting mean weight and condition index for the respective age-sex class from each respective trapping period. �49 Instrumentation Five male and 5 female mallards were instrumented with subcutaneous implant radio transmitters 12-13 December 1988. Birds were anesthetised, then a 9 g transmitter was implanted dorsally at the base of the neck with the 16 cm whip antennae inserted subcutaneously to the hip joint. Anterior and posterior sutures on the transmitter helped hold it in place. During the same trapping period, 5 male and 5 female mallards were instrumented with radio packages similar to those used in 1987 and 1988. The latter birds were instrumented to aid in assessing the comparative effects of the subcutaneous implant radios and to provide an estimate of foraging time through continuous monitoring. During the January trapping period, 5 adult females were instrumented with 9 g transmitters glued on a plastic-coated nylon neck collar. These birds were monitored to evaluate the use of the collar for attaching the transmitters. Poor survival of mallards instrumented with implant transmitters prompted the use of a neck collar radio attachment. During the March trapping period, 54 neck collar-attached transmitters were placed on adult females. Instrumented birds were monitored regularly for the first 3 weeks after instrumentation and then not located again until mid-May. Due to high mortality of females instrumented with the flexible collar, we designed a collar made of polyvinal chloride (PVC) that would reduce mortality resulting from the bird getting its bill caught in the collar. Eight of these units were deployed during April 1989. During May, instrumented females were located from the ground and air as in previous years (Ringelman and Szymczak 1988). When an instrumented female was located, a ground check was made to determine whether the birds was nesting. If the female was nesting, egg length, breadth, and weight were recorded for each egg. Nest location, cover type, and incubation stage were also recorded. After the estimated hatching date, the nest was checked to determine nest success and to collect a down sample. Carcass Collection As in 1987-88, wintering waterfowl concentration areas and raptor perches were searched for waterfowl wings or carcasses from 20 January - 1 April 1989. Species, age, sex, marsh unit where collected, date, and band numbers (if bands were present) were recorded. If an ulna was available, one wing was retained and frozen from all mallards collected by our reseach crew, and from all banded birds collected independently by the refuge staff. Frozen wings were later analyzed for lipids in the ulna (Ringelman and Szymczak 1988). The January condition indices of the wing-banded sample of mallards were compared, by age and sex, to the condition indices of the wing-banded mortalities to determine whether the condition distributions of those birds dying differed from the distributions of those birds marked. Each sample was analyzed for normality using the UNIVARIATE procedure (SAS Institute 1985) and a Wilcoxon rank sum test to compare condition distributions. Wings retained for analyses were labeled and frozen in airtight bags. Ulnas were excised, cracked open, and the marrow touched to a clean sheet of white paper. The resulting blot was examined as in 1987-88 to evaluate lipid content of the ulna (Ringelman and Szymczak 1988). A 2x2 chi-square table was used to determine if similar percentages of banded and unbanded birds appeared to have starved. �50 To determine the percentage of carcasses collected in the areas searched, 65 carcasses with wing bands were placed around 8 water areas. Carcasses were placed in areas where remains had previously been recovered, and in some cases marked carcasses were exchanged for unmarked carcasses. Only the person planting the carcasses knew when and where carcasses were planted. Afterwards, collected carcasses were examined for wing bands from the planted carcasses, and wing band and marsh unit number recorded. Aerial Photographs Beginning 28 December 1988 and ending 15 February 1989, weekly aerial censuses were conducted on the MVNWR using a Cessna 182. Color, 35mm slides were taken from 500 ft. elevation through an open window with a Minolta Fl equipped with a 200 mm lens and skylight filter. An attempt was made to overlap photos. After development, transparencies were projected on a screen, overlap areas excluded, and ducks counted using a mechnical marker pen counter. Numbers of identifiable waterfowl were recorded for each flight. Mallard sex ratios were determined from transparencies taken on 28 December 1988 and 18 January 1989. Field-feeding Trials Wire panels were used to enclose 64 m2 of standing barley on MVNWR. Twelve captive mallards (6 of each sex) were transported to the enclosure daily until they appeared to forage normally. Thereafter, the enclosure was moved to a site with abundant standing grain, and the birds starved for 18 hr. Six mallards (3 of each sex) were weighed to the nearest gram on an electronic digital scale immediately before the trial. Mallards were released gn ~ into the enclosure which had been moved to a site with abundant standing grain. Test birds were allowed to forage for precisely 5 minutes then reweighed. The amount of barley ingested was assumed to equal the difference between starting and ending body mass. Particle Marker Fluorescent particles (AX series pigments, Day-Glo Color Corporation) were placed in the inflow to the impoundment in Unit 24 on the MVNWR on 3 and 5 January 1989. Particle marke r was mixed as suggested by Godfrey (1987) and siphoned into the inflow. Other water areas on the MVNWR were allowed to freeze so the only open water was in Unit 24. During subsequent trapping periods birds were examined under a high-intensity ultraviolet light for fluorescent particles. Initially, a bird was considered marked if one particle was found. During the March trapping period, a bird was considered marked if multiple particles were found. i Pair and Brood Counts A survey route was established on MVNWR and driven weekly from 22 April through 14 June 1989. Male mallards encountered were classified as paired (with female), lone male (single isolated drake without a visible associated hen), or grouped (2-4 associated drakes). Groups of 5 or more males were excluded. Broods encountered along the route or at any other time were recorded as to 5pecie~, number, and age. Brood ages were used to back-date to the estimated hatching date. �51 Capture of Nesting Females Mallard nests were located on MVNWR. During the initial encounter with the nest, the clutch size and incubation stage were recorded. During the final 10 days of incubation, we attempted to capture the female with a hand-held net, net gun, or nest trap. When a female was captured, greater secondary coverts 5 and 11, and primary V were removed for later analysis to determine the female's age (Gatti 1983). Clutch age, and egg length, breadth, weight, and fertility status were recorded. Nests were checked after the estimated hatch date to determine fate. Down Collection Differences in the trace element composition of grain consumed in winter could result in differences in the trace element composition of female basic plumage, which is normally produced during winter (Weller 1976). Such differences could then be used to evaluate the productivity of San Luis Valley winter residents compared to migrants originating south of the SLV. To address this hypothesis, barley grown in the San Luis Valley, corn grown near the Bosque del Apache National Wildlife Refuge, New Mexico, and corn grown near Lubbock, Texas, was harvested and analyzed for trace elements using an inductively coupled plasma machine at the Colorado State University Soils lab (Table 1). The general area of grain collections are locations in which mallards nesting in the San Luis valley may winter. Table 1. Analysis of grain samples for selected elements. All values are in ppm. Analyses done on 19 January 1988 at the Colorado State University Soils Lab using an inductively coupled plasma machine. Element Location Grain Mn San Luis Valley Barley San Luis Valley Barley Parmer, Texas Cu Ti Sr Ba 15.8 7.2 0.3 3.47 1.38 18.7 5.8 0.8 3.58 2.28 Corn 7.6 2.0 <0.1 0.56 0.19 Castro, Texas Corn 6.0 2.9 <0.1 0.38 0.11 New Mexico Corn 5.0 1.6 0.2 0.59 0.20 New Mexico Corn 7.4 1.5 <0.1 0.47 0.07 New Mexico Corn 7.2 1.6 <0.1 0.32 0.03 New Mexico Corn 7.3 1.6 <0.1 0.65 0.12 New Mexico Corn 6.8 1.6 <0.1 0.39 0.09 �52 Captive females were fed barley (from the SLV) or corn during the prebasic molt. After molt was completed, down was harvested from the live birds, then washed in an ultrasonic bath for 5 minutes each with diethyl ether, distilled water, and acetone. Acid digestion and analysis of down samples were conducted at the Soils lab in the same manner as with grain samples. Down samples were then compared for differences in trace element composition similar to those detected in grain samples. Nest bowls containing down from wild females nesting on MVNWR were collected after hatch or predation and placed in plastic bags. These samples were processed in a manner similar to the down collected from the captive birds. RESULTS Weight Changes of Marked and Unmarked Mallards Weight and condition indices were approximately normally distributed. During each banding period, males weighed more than females and adults weighed more than immatures (Duncan's Multiple Range tests, P<O.OS). Mallards weighed more during the December trapping period (Duncan's Multiple Range test, P<O.05), whereas weights during the other 3 periods were similar (Table 2). Condition indices were highest during December, followed by March and February. The lowest condition indices were recorded during the January trapping period (Duncan's Multiple Range test, P<O.OS). Adults were in better overall condition than immatures. Adult males and females had similar condition indices during each trapping period except in March, when adult females were in better condition (Table 3). Generally, immature males and females were in similar condition during each trapping period (Table 3). During February, 54 mallards were captured with bait traps and 139 with cannon nets. Weights of these mallards did not differ by capture method (Duncan's Multiple Range test, P-O.9S32). Mean weights of mallards were similar in all trapping periods (Figs. 14). Twenty-eight adult females, 184 adult males, 39 immature females, and 58 immature males were recaptured within 7 days. These mallards tended to weigh less than their original weights (T--2.20, P-O.0367, T-2.70, P=O.0076, T=-2.14, P=O.0387, andT--4.80 P-O.0001, for adult females, adult males, immature females, and immature males, respectively; Figs. 5 and 6). Mallards captured during one period and recaptured during su~sequent trap periods also tended to have lower weights at recapture (Table 4). Fifty-seven mallards banded in 1986-87 were recaptured in 1988-89: 1 adult female, 33 adult males,S immature females, and 18 immature males. Condition indices in 1988-89 were positively related to condition indices in 1986-87 for adult males (F-9.24, 32 df, P-O.0048), but not for immatures of either sex (F-2.S7, P-O.1283 and F-l.56 , P-O.300l for males and females respectively). Relative condition indices were positively related for adult males (F=9.13, P=O.0050, Fig. 7) but not for immatures (F-3.43, P-O.0827 and F-l.40, P=O.3224, Figs. 8 and 9 for immature males and females, respectively). One hundred and sixty-three birds (18 adult females, 92 adult males, 14 immature females, and 39 immature males) captured in 1987-88 were recaptured in 1988-89. Condition indices for adult females in 1989 were not related to those in 1988 (F-2.22, 17 df, P-O.1553), but they were positively related for the other age-sex classes (F-S.44, 91 df, P-O.02l9, F-17.l4, 38 df, P-O.0002, and F-15.18, 13 df, P-O.002l for adult males, immature males, and immature females, respectively). Relative condition indices in 1987-88 were positively related �53 1200 1150 r- 1100 r- 1050 r- (43) I- 1000 r- e 950 ~ 900 r- 850 f- 800 r- - 0) J: iii > o o [Xl 750 .•. UNMARKED 6. RECAPTURE .. ( 181) - (417) (50) T .- t ~ [ (21) (8) (30) - 700 DEC JAN TRAPPING FEB PERIOD MAR Fig. 1. Mean weights (± SE) of adult female mallards captured in the San Luis Valley, Colorado, during 4 trapping periods in 1988-89. Sample sizes are given in parentheses with unmarked samples above and recaptures below the standard errors. 1200 (78) (82) 1150 ( 1158) 1100 C, •...• 1050 ~ 1000 ~ iii 950 ~ > o 900 [Xl 850 o [195) t - (83) I UNMARKED 800 RECAPTURE 750 (22) 700 DEC JAN TRAPPING FEB MAR PERIOD Fig. 2. Mean weights (± SE) of adult male mallards captured in the San Luis Valley, Colorado, during 4 trapping periods in 1988-89. Sample sizes are given in parentheses with unmarked sample above and recapture sample below the standard errors. �54 1200 .• UNMARKED D RECAPTURE 1150 -- 1100 m 1050 I- ::r:: 1000 iii 950 <!J (39) 3: >- I 900 0 0 III 850 -I 800 750 (34) - (85) T (306) II r•• - 1 X I f- c: II (4) (10) (45) 700 DEC JAN TRAPPING MAR FEB PERIOD Fig. 3. Mean weights (± SE) of immature female mallards captured in the San Luis Valley, Colorado, during 4 trapping periods in 1988-89. Sample sizes are given in parentheses with unmarked sample above and recapture sample below the standard errors. 1200 C, 1150 E 1100 ~ 1050 I- ::r:: 1000 Q w 950 3: >- c 0 III 900 (45) P ._A ~I I•... 800 750 700 TII D RECAPTURE A 1 (32) I ~ (9) L t UNMARKED (440) I 850 ii i A -- (131) I II .6. I I Ii i 1 I I 1 - I I (33) (65) I DEC JAN TRAPPING FEB MAR PERIOD Fig. 4. Mean weights (± SE) of immature male mallards captured in the San Luis Valley, Colorado, during 4 trapping periods in 1988-89. Sample sizes are given in parentheses with unmarked sample above and recapture sample below the standard errors. �55 110 ADULT t- ::t: (!J IMMATURE (10) ~ 105 (72) >Q o m I t f I ~) (85) (34) (2) ..J ~ 100 z a a:o t- Z w 95 ( 17) o IX: W e, (28) (1) ••• (10) 90 1 2 3 4 DA YS BETWEEN 5 6 7 RECAPTURE Fig. 5. Weights (as percent of initial capture weight) of adult and immature male mallards recaptured within 7 days of initial capture in the San Luis Valley, Colorado, during 198889. Sample sizes are given in parentheses with adults above and immatures below the standard errors. 110 t- ::t: (!J W == 105 >Q o m ..J ~ 100 - a a: o t- Z w 95 o IX: i- (1) r I 90 6 IMMATURE I r r II (7) (9) 6. 1 tT- tT( 14) e, AOULT ( 11) (7) W ••• t L 6 (1 ) (7) (10) I 1 2 3 4 DAYS BETWEEN 5 6 7 RECAPTURE Fig. 6. Weights (as percent of initial capture weight) of adult and immature female mallards recaptured within 7 days of initial capture in the San Luis Valley, Colorado, during 198889. Sample sizes are given in parentheses with adults above and immatures below the standard errors. �56 en co I co co .•.. 0) 15 89CONDITIONoO.40(87CONDITION)-0.34 '00.48, poO.OOSO 10 ~ )( UJ 5 a ~ z 0 0 z -5 • Ea 0 0 UJ > i= -10 « ..J UJ a: -15 -15 -10 -5 o 5 10 15 RELATIVE CONDITION INDEX IN 1986-87 Fig. 7. Relative condition indices of adult male mallards captured in 1986-87 and recaptured in 1988-89 in the San Luis Valley, Colorado. en co I co co en .•.. 15 89CONDITIONoO.97(87CONDITION).0.O 1 RoO.42, poO.0827 10 ~ )( UJ 5 a ~ z o o ~ -5 E a o UJ > i= -10 « • ..J UJ a: -15 -15 -10 -5 o 5 10 RELATIVE CONDITION INDEX IN 1986-87 Fig. 8. Relative condition indices of immature male mallards captured in 1986-87 and recaptured in 1988-89 in the San Luis Valley, Colorado. 15 �57 0) co I co co ,.. 0) 15 88CONDITION.-0.82(87CONDITION)+2.311 ,.0.51, P·0.3224 10 ~ >< 5 UJ Q ~ Z 0 j: 0 Z 0 -5 is o UJ > j: -10 <t ...I UJ c:: -15 -15 -5 -10 o 5 10 15 RELATIVE CONDITION INDEX IN 1986-87 Fig. 9. Relative condition indices of immature female mallards captured in 1986-87 and recaptured in 1988-89 in the San Luis Valley, Colorado. 15 0) co 8I1CONDITION·0.82(88CONDITION).1.33 ,·0.23, P·0.02110 I co co 10 ,.. 0) ~ >< UJ 5 Q ~ Z o o ~ C ~ o -5 UJ > ~ -10 <t • ...I UJ c:: -15 -15 -10 • • -5 0 5 10 RELATIVE CONDITION INDEX IN 1987-88 Fig. 10. Relative condition indices of adult male mallards captured in 1987-88 and recaptured in 1988-89 in the San Luis Valley, Colorado. 15 �58 for adult males (F-4.92, 91, df, P-0.0290; Fig. 10), immature males (F-13.68, 38 df, P-0.0007; Fig. 11), and immature females (F-16.05, 13 df, P-0.0017; Fig. 12). The relationship for adult females approached significance (F-4.30, 17 df, P-0.OS46; Fig. 13). Table 2. Mean (± standard error) for weights of mallards captured in the San Luis Valley during winter 1988-89. Letters a-d indicate significant differences among means (P-O.OS) within an age-sex class. Letters w-z compare age-sex classes within a trapping period. Trapping Period Adult Immature Female Male Female 12-13 Dec 1063(82)aw n-73 927(92)ay n-43 985(87)ax n-45 882(77)az n-38 12-17 Jan 1025(82)bw n-llS8 893(76)by n-4l7 958(88)bx n=440 83l(88)bz n-306 9-10 Feb 1022(135)bw n-78 894(64)by n-50 953(62)bx n-32 871(68)ay n-34 27 Feb- 2 Mar 1022(79)bw n-254 942(64)ax n-l61 942(75)bx n-13l 855(71)aby n-8S Male Table 3. Mean (± standard error) for condition indices of mallards captured in the San Luis Valley during winter 1988-89. Letters a-d indicate significant differences among means (P-0.05) within an age-sex class. Letters w-z compare age-sex classes within a trapping period. Trapping Period Adult Male Female Immature Male Female 12-13 Dec l4.5(4.l)aw 14.2(S.7)bw ll.9(4.2)ax 12-17 Jan 11.8(4.0)bw 12.0(4.7)cw 9-10 Feb l2.3(3.1)bw l2.4(3.8)cw 10.4(2.9)abx 11.8(4.1)awx 27 Feb- 2 Mar l2.1(3.6)bx lS.7(3.6)aw 10.1(3.9)by 9.9(4.6)bx l3.4(4.S)awx 9.8(4.S)bx l2.3(4.1)ax �59 0) co I co co 0) .,.. 15 S8CONDITION-0.44(SSCONDITION)·0.72 ,-0.52, P-0.0007 10 ~ >< w 5 ~ Z 0 0 0 i= C z 0 -5 i= -10 c w > « • ..J w a:: -15 -15 -10 -5 o 10 5 15 RELATIVE CONDITIONINDEX IN 1987-88 Fig. 11. Relative condition indices of immature male mallards captured in 1987-88 and recaptured in 1988-89 in the San Luis Valley, Colorado. 15 0) CO 88CONDITION-O.88( SSCONDITION)-0.30 I ,-0.78, P- O.0 017 CO co .,.. 0) 10 ~ >< W 5 o ~ z o o ~ -5 Eo o w > ~ -10 -e ..J w a:: -15 -15 -10 -5 o 5 10 RELATIVE CONDITIONINDEX IN 1987-88 Fig. 12. Relative condition mallards captured in 1987-88 San Luis Valley, Colorado. indices of immature female and recaptured in 1988-89 in the 15 �60 0) co I co co .•. en 15 88CONDITION·O.42(88CONDITION)-1.08 P.0.0548 10 ~ >< IJJ ,.0.48, •• 5 C 3; Z o i= o ~ -5 • is o •• IJJ > i= <C -10 ..J IJJ I%: -15 -15 -10 -5 • o 5 10 15 RELATIVE CONDITION INDEX IN 1987-88 Fig. 13. Relative condition indices of adult female mallards captured in 1987-88 and recaptured in 1988-89 in the San Luis Valley, Colorado. 250 , LIMITED SEARCH TIME , LIMITED SEARCH TIME 200 ~ 150 I%: co o <C IJJ c 100 50 \ o FEB 1 FEB 15 MAR 1 MAR 15 APR 1 WEEK Fig. 14. Number of dead waterfowl collected weekly between 17 January and 1 April 1989 on the Monte Vista NWR. �61 Table 4. Mean differences (± standard error) in weights of mallards trapped during one banding period and recaptured during subsequent periods. Means with different letters are significantly different (P<O.OS). Initial Capture Period Recapture Period Male Adult Female Dec Jan -46(66)a n-24 -54(37)a n-4 Dec Feb Dec Mar -60(64)a n-3 -38(12)a n-3 Jan Feb Jan Mar -64(201)a n-22 -26(66)b n-40 -9(34)a n-6 36(66)a n-14 Feb Mar l27(369)a n-8 Sl(30)a n-2 Immature Male Female 1(81)a n-9 -102 n-l -251b n-l -42(36)a n-7 -13(54)a -14(43)a n-8 n-5 -23(67)b 3(6l)ab n-29 n-7 16a n-l -31(26)a n-2 Instrumentation Poor signal reception and high mortality of the mallards instrumented with the subcutaneous transmitters in December prevented use of these birds for monitoring foraging behavior. Two of the birds with subcutaneous implant radios were killed by hunters. One of the back-pack harness radios applied in December was shot. Each of four birds instrumented with back-pack transmitters were monitored for 16 hr periods. They spent 48.5 (± 15.2) min field-feeding, while the field-feeding flights on these days lasted 133.6 (± 39.5) min. Thirty-six of 54 females (67%) instrumented in late February and early March were recovered during the month. All birds had their bill caught in the neck collar. Those collars recovered without accompanying carcasses also showed evidence of the bill being caught (top edge rolled over in 2 places approximately 3/4 of an inch apart). Of the 18 instrumented females not recovered, only 9 could be located during the final week of the March. Radio packages on the 9 missing birds may have failed because of broken antenna; 13 radios recovered had broken antenna. In March, 6 birds (3 wing-clipped and 3 free-flying) were equipped with radio collars constructed of PVC pipe material. Two of the 3 wing-clipped birds released on 21 March were recaptured 24 March. These birds, a male and a female, had lost lS8g and 116g, respectively. The third bird, a female that was crippled when released, was found dead. The 3 free-flying birds, all females, were subsequently located with other mallards, but were not making f i eLd-feeding flights as most other mallards appeared to be doing. An additional five females were equipped with these radio collars in April. �62 Three females (2 with nylon collars and 1 with a PCV collar) were alive in May. Only 1 female nested. The female with the PVC collar, instrumented in April, nested on the MVNWR in baltic rush (Juncus balticus). The nest was located on 7 June 1989, had 5 eggs, appeared to have been partially predated, and was at about 17 days incubation. She ultimately hatched 3 eggs. Carcass Collection One thousand, seven hundred and thirty-eight wings were collected by the maintenance crew and our research crew. Of these, 131 wings were from banded birds. Numbers of carcasses collected on a weekly basis fluctuated (Fig. 14), primarly due to variable search effort. Suspected causes of death included avian cholera, starvation, lead poisoning, predation, and collisions with powerlines. Of the 591 carcasses whose age and sex could be determined, 283 (40.3%) were adult males, 96 (16.2%) were immature males, 162 (27.4%) were adult females, and 95 (16.1%) were immature females. The distribution of condition indices for banded birds found dead were not different from the distribution of condition indices of their cohorts during January banding (z--1.64, P-0.1000; z--O.72, P-0.4689; z--l.33, P-0.l845; z--0.72, P-0.472l Wilcoxon sign rank test for adult females, adult males, immature females, and immature males, respectively), indicating death was independent of condition. No apparent peaks in mortality related to condition class at banding were apparent (Figs. 15-18). Of the 1,017 ulnas analyzed for lipid content, 68 (6.7%) were from birds that had starved. Twenty-six of 106 banded birds (24.5%) found dead and analyzed for ulna lipids appeared to have starved. Banded birds apparently starved at a greater rate than unmarked birds (42 of 911 samples, 4.6%; X2-60.38, P-O.0000) . Fifteen of 20 (75%) samples from instrumented females appeared to have starved. Of 65 carcasses wing-banded and placed out to determine recovery rates, 41 wings (31.5% of the 130 wings), representing 23 birds (35.4%) of the birds, were recovered. Eight leg bands recovered from an eagle roost were from birds also wingbanded. Of these eight birds, only 1 (12.5%) had been recorded from our searches of the refuge. Recovery of the planted carcasses suggest that the 1,677 wings recovered represent 4,736 dead birds. Aerial Photographs Counts from aerial photographs were too variable to give identifiable population trends (Table 5). Sources of inconsistencies included bird movements to areas not photographed, photographs too blurred for accurate counts, inclusion of other waterfowl species in the counts, and 1 roll of film lost by the developer. Sex ratio counts of 1,830 mallards on 28 December 1988 and 1,135 on 18 January 1989 indicated 59.9% and 58.8 % males, respectively. The decrease in the number of males was significant (X2-6.4846, P-0.0109). Field-feeding Trials When trials in which birds appeared to lose weight are excluded, females obtained 0.92 g/min (± 0.77, range 0-2.4, n-27) and males 1.50 g/min (±O 99, range 0-4, n-31) of barley from fields on MVNWR. There were differences in the rate of consumption between sexes (F-6.05, P=0.0170) and individuals (F=8.69, P-0.0047) but no individual*sex interaction (F-0.89, 1 df, P-0.3507). Males consumed standing grain heads while females were only observed foraging on shelled grain. �63 20 0 15 ~ "GOOD" CONDITION ~ "AVERAGE" CONDITION •• LIJ I0 LIJ ..J ..J 0 10 "POOR" CONDITION 0 CC LIJ £D ~ ;:, Z 5 o JAN 15 FEB 1 FEB 15 MAR 1 MAR 15 APR 1 WEEK OF COLLECTION Fig. 15. Number of weeks between release and recovery of wing-banded adult female mallards in the San Luis Valley, Colorado, 1989. 20 ~ "GOOD" CONDITION ~ "AVERAGE" CONDITION •• "POOR" CONDITION o 15 LIJ I- o LIJ ..J ..J o o 10 CC LIJ CD ~ ::::) Z 5 o JAN 15 FEB 1 FEB 15 MAR 1 MAR 15 APR 1 WEEK OF COLLECTION Fig. 16. Number of weeks between release and recovery of wing-banded mallards in the San Luis Valley, Colorado, 1989. �64 20 0 15 w .... .... 0 "GOOD" CONDITION ~ "AVERAGE" CONDITION •• w t0 0 ~ "POOR" CONDITION 10 a:: w CD ~ ::) Z 5 o JAN 15 FEB 1 MAR 1 FEB 15 MAR 15 APR 1 WEEK OF COLLECTION Fig. 17. Number of weeks between release and recovery of wing-banded immature female mallards in the San Luis Valley, Colorado. 20 !2Z2l "GOOD" CONDITION ~ "AVERAGE" CONDITION •• "POOR" CONDITION o 15 w t- O w .... .... o 10 o a:: w CD :E ::) Z 5 o JAN 15 FEB 1 FEB 15 MAR 1 MAR 15 APR 1 WEEK OF COLLECTION Fig. 18. Number of weeks between release and recovery of wing-banded immature male mallards in the San Luis Valley, Colorado. �65 Table 5. Number of waterfowl counted from color slides taken during aerial flights. Flight date Number counted Nunmber + possible missed 28 December 1988 32,325 32,841 4 January 1989 22,697 23,001 11 January 1989 21,955 22,012 18 January 1989 27,413 28,011 25 January 1989 14,119 14,464 1 February 1989 26,350 27,056 8 February 1989 Developer lost 1 box - it is still missing 15 February 1989 21,003 21,557 Particle Marker Most if not all of the mallard population concentrated on the wetland with particle marker during early January, thus we assumed that all birds were exposed to and initially marked. By March, birds showed large patches of marker on the wing lining and around the vent. As a test to verify that only winter residents were marked, blue-winged teal (Anas discors) and other species not resident during winter in the SLV were also examined. Unfortunately, some individuals of these species showed flecks of color similar to those evident on mallards. Further investigation revealed that the source of the marker appeared to be the wetland where the marker was initially applied; captive mallards penned in this wetland were still being marked in March. Subsequent examinations identified a faint, colored sheen that was apparent only on some mallards, suggesting that this marking pattern might be indicative of winter-marked birds. However, lacking a control in the form of known winter-marked birds, the technique was abandoned as a means to identify winter residents. Pair and Brood Counts Numbers of paired, lone, and grouped males varied among census periods (Fig. 19). In mid-June, mixed flocks of males and females were observed, but no large concentrations had developed. A hatching curve (Fig. 20) developed from observations of 142 mallard broods indicated a prolonged hatch with no discernable peak, similar to that which occurred in 1987 (Ringelman and Szymczak 1988). The initial estimated hatch dates of the first week in May precede that of 1987 and 1988 by 2 weeks. �66 250 •• PAIR 200 ~ LONEMALE 175 ~ GROUPED MALES 225 o w ~ 150 o o 125 ::l en w ..J <t 100 ::E 75 50 25 o 4/22 4/30 5/6 5/14 5/22 5/30 6/8 6/14 DATE OF COUNT Fig. 19. Number of male mallards counted from a census route on the Monte Vista NWR and classified as paired, lone, or grouped from mid-April through mid-June, 1989. 30 25 en 0 0 0 20 a: CD IL 0 15 a: w CD ::E ::l 10 Z 5 0 MAY 1 MAY 15 JUNE 1 JUNE 15 JULY 1 WEEK Fig. 20. Estimated hatching dates of mallard broods encountered in the San Luis Valley, Colorado, in 1989. JULY 1 5 �67 Capture of Nesting Females Thirty-four incubating females were captured. Measurements of the feathers collected from the nesting females will be made during the fall of 1989, and any analyses relating female age to clutch parameters made then. Down Collection Preliminary analyses of grain samples suggested identifiable differences between grain grown in the SLV and grain grown in New Mexico, and near Texas. Initial analyses of down samples of captive birds fed these grains did not prove useful in determining which grain sample a bird was fed (Table 6). Further analyses will be conducted in the fall of 1989. Table 6. Concentrations (ppm) of selected trace elements found in down samples collected from 6 captive female mallards fed barley from the San Luis Valley or corn from Colorado. Element Grain Bird Mn Cu Ti Sr Ba Barley 5 5.2 7.0 2 2 50 Barley 8 3.4 5.7 1 1 <1 Barley 46 3.5 5.1 2 1 <1 Corn 1 3.7 6.3 3 1 1 Corn 7 3.4 5.0 1 1 <1 Corn 39 4.0 6.6 3 1 1 DISCUSSION Temperatures were mild (Fig. 21), snow cover light (Fig. 22) and food readily available in 1988-89. Therefore, it is interesting that mean weights of mallards captured in 1988-89 were similar to those of birds captured in 198788, during a more severe winter. The relationship of relative condition indices and relatively constant weights and condition indices between years suggest that condition indices are not completely controlled by environmental factors. The relationship of relative condition indices between years suggest that there may be a genetic component influencing winter condition of mallards in the San Luis Valley. The tendency for weights to be less at recapture may be the result of a handling effect, or that birds in relatively "poorer" condition may be more likely to re-enter a trap. Since many of the year to year recaptures were in �68 DAILY MAXIMUM 20 \ DAILY MINIMUM 10 IU a: 0 ::::) /\ I- f \:'\ ~ a: IU -10 e, \:". ~ .........J\ ,/: IU I- -20 . .... ' " ._ t·, \t :.; -30 DEC 1 DEC 15 JAN 1 JAN 15 FEB 1FEB 15 MAR 1MAR 15 DATE Fig. 21. Daily temperature maxima and minima recorded at the Alamosa airport, Alamosa, Colorado, 1988-89. 10 ""' E CJ ....•. :t: I- fuc 5 - r-1 - :: o Z ._, en o DEC 1 DEC 15 JAN 1 JAN 15 '-----.. FEB 1FEB 15 MAR 1MAR 15 DATE Fig. 22. Depth of snow on the ground at the Alamosa airport, Alamosa, Colorado, 1988-89. �69 relatively "poor" condition, and there are no obvious differences in survival related to body condition, it seems most likely that birds in relatively "poor" condition are more likely to re-enter a trap. As has been previously noted (Ringelman and Szymczak 1988), winter mortality in the SLV is high. Although avian cholera was not as prevalent in 1988-89 as in 1987-88, substantial numbers of birds still died during the winter period. It is difficult to estimate of the total number of ducks dying during January to April 1989. One third of the planted carcasses were recovered, while only 12.5% of the leg bands recovered from an eagle roost were represented by wings (wingbands) recovered during carcass searches. The recovery rate of planted carcasses is probably atypically high since carcasses were placed in areas where they should have been found. The recovery rate of wingbands compared to corresponding bands found at the eagle roost probably is closer to the actual recovery rate of ducks which died on MVNWR. Pair and brood counts suggest that the nesting period was advanced about 2 weeks in 1989 compared to 1987 and 1988. This may be the result of the mild winter and spring in 1989. The prolonged hatching curve (Fig. 20) suggests that female mallards came into breeding condition over a prolonged period, possibly because of a wide variation in winter contion. Field-feeding trials suggest that males may be more efficient at foraging in standing barley fields. This may result from the observation that females foraged on shelled grain while males readily took standing grain. To consume the 57 g of steptoe barley needed for maintenance at -9 to -10 C (Ringelman and Szymczak 1988), a male would have to forage for 38 minutes, while females must forage 62 minutes. Activities, such as flight and courtship, would increase energetic requirements thereby increasing foraging time. LITERATURE CITED Dill, H. H., and W. H. Thornberry. 1950. A cannon projected capturing waterfowl. J. Wildl. Manage. 14:132-137. net trap for Gatti, R. C. 1983. Spring and summer age separation techniques for the mallard. J. Wildl. Manage. 47:1054-1062. GOdfrey, R. D., Jr. 1987. Experimental mass-marking of waterfowl wintering on the Southern High Plains of Texas. M.S. Thesis, Texas Tech Univ., Lubbock, TX. 66 pp. Hopper, R. M., A. D. Geis, J. R. Grieb, and L. Nelson, Jr. 1975. Experimental duck hunting seasons, San Luis Valley, Colorado, 1963-70. Wildl. Monogr. 46. 68pp. Ringelman, J. K., and M. R. Szymczak. 1985. A physiological condition index for wintering mallards. J. Wildl. Manage. 49:564-568. Ringelman, J. K., and M. R. Szymczak. 1988. Winter survival and reproductive success of female mallards. Wildl. Res. Rep. October 1988. pp 69-124. Rutherford, W. H., and C. R. Hayes. 1976. Stratification as a means for improving waterfo.wl surveys. Wildl. Soc. Bull. 4:74-78. SAS Institute, Inc. 1985. SAS procedures guide for personal computers, version 6 edition. Cary, NC. 373 pp. �70 LITERATURE CITED (cont.) Szymczak, M. R. 1986. Characteristics of duck populations in the intermountain parks of Colorado. Colorado Div. Wi1d1. Tech. Pub1. 35. 8pp. Szymczak, M. R., and J. F. Corey. 1976. Construction and use of the Salt Plains duck trap in Colorado. Colorado Div. Wi1d1., Div. Rep. 6. 13 pp. Weller, M. W. 1976. Molts and plumages of waterfowl. pp. 34-38 IN Bellrose. Ducks, geese & swans of North America. Stackpole Harrisburg, PA. Prepared by: )11J"ql72 ~ Michael R. Szymczak Wildlife Researcher C F. C. Books, g-K~ James K. Ringelman Wildlife Researcher C �71 Colorado Division of Wildlife Wildlife Research Report October 1989 JOB PROGRESS REPORT State of __~C~o~l~o~r~a~d~o~ Project 01-03-212 Work Plan 22 Job Title: : Job Migratory Game Bird Research _2_ Migratory Bird Publications Period Covered: Author: _ 01 April 1988 through 31 March 1989 Michael R. Szymczak Personnel: James K. Ringelman and Michael R. Szymczak, Wildlife Colorado Division of ABSTRACT The following list contains those articles that were published or completed and ready for publication during this segment: Ringelman, J. K. 1988. Examining waterfowl condition: skewed ideas on the normal procedure. Pages 277-285 in M. W. Weller, ed. Waterfowl in winter. University of Minnesota Press, Minneapolis. Ringelman, J_. K., W. R. Eddleman, and fl. W. Miller. 1989. l:lighplains -__-_ in L. M. Smith, R, L. Pederson and reservoirs··and sloughs. Pages R. M. Kaminski, eds. Habitat management for migratiI).gand .wintering waterfowl in North America. Texas Tech Press, Lubbock. (In press).· Prepared by: ~ Z; ~ James K. Ringelman Wildlife Researcher C � https://cpw.cvlcollections.org/files/original/6ddb090ef09bd5990c93850e5662be2d.pdf 64e879cd02f114870691d0a815306a6d PDF Text Text JOB PROGRESS REPORT State of ~C~o~l~o~r~a:d~o _ Project: (W-150-R-3) Period Covered: 1 July, 1989 - 30 June, 1990 : Peregrine Falcon Restoration Program Personnel: G.R. Craig, Colorado Division of Wildlife and J.H. Enderson, The Colorado College. ABSTRACT Peregrine falcon population recovery continued in Colorado. In the 1990 breeding season, 44 territories were occupied by 37 breeding pairs that fledged 62 young. The West Slope subpopulation consisted of 35 occupied sites that continued to exhibit good productivity (1.5 young per total pair) without remedial activities. On the East Slope, only 5 of the 9 occupied sites were successful but averaged 1.38 young per total pair which was sufficient for population maintenance. Eggshell thicknesses in 1990 averaged 10% thin (n = 42). Due to insufficient representation (n = 4) East Slope thickness averages were not calculated. Contents of 11 nonviable eggs were submitted for organochlorine analysis. Hacking efforts were confined to three East Slope sites. Fifteen falcons were released and 12 successfully achieved independence. All the hacked young resulted from recycling 5 wild breeding West Slope pairs. This Job Progress Report represents a preliminary analysis and is subject to change. For this reason, information presented herein MAY NOT BE PUBLISHED OR QUOTED without permission of the author. ��PEREGRINE FALCON RESTORATION PROGRAM Gerald R. Craig SEGMENT OBJECTIVES 1. Annually monitor the number of breeding pairs of peregrines and their reproductive success in Colorado. 2. Annually monitor organochlorine peregrines in Colorado. 3. Monitor breeding population turnover through band recoveries, presence of color markers, and telephotographic identification of individual breeding adults. 4. Augment poor wild production by placement of captive hatched wild young and captive produced young into occupied wild nests. 5. Release captive hatched and captive produced young at potential and vacant wild territories. 6. Monitor recruitment of reintroduced pereg:--inesinto the wild breeding population of Colorado. pesticide levels in wild breeding METHODS AND MATERIALS 1. Visit all known peregrine breeding territories throughout Colorado and obzerve them from a distance to establish the presence of breeding adults. Breeding pairs will be kept under surveillance to determine initiation of egg laying. Depending upon the individual female's reproductive history and eggshell condition (obtained through measurement of previous year's eggshell thicknesses) and availability of captive hatched young for release, breeding pairs either will monitored or manipulated as outlined in approach 4. Those pairs not designated to be manipulated will be revisited periodically throughout the nesting season to document reproductive success. When a pair's behavior indicates that egg laying has occurred and tncubat i on is underway, the eyrie will be visited to document the number of eggs produced. The eggs wi 11 be candled to ascertain viability and approximate age. All nonviable eggs will be collected for chemical analysis. A second visit will be made to determine productivity, band nestlings, and collect eggshell fragments and unhatched eggs for thickness measurement and analysis under 2a and 2b. 2a. Eggshell fragments encountered during eyrie visits described in approaches 1 and 4a will be measured for index to thickness following standardized procedures. 2b. Whole, nonviable eggs which are encountered during eyrie visits will be collected, preserved and submitted to the appropriate Fish and Wildlife Service approved laboratory for pesticide analysis. Eggs collected from the wild in the course of Approaches 4a, 4b and 4c that are artificially �at the Peregrine Fund's Boise, Idaho facility also will be submitted for shell thickness measurement and chemical analysis. 3. Peregrines present at breeding territories will be examined to determine the presence of bands or color markers. Band confirmation will be accomp 1ished through observation from a distance with telescopes and concealed remote controlled cameras. When banded falcons are encountered, every effort will be made to read band numbers without trapping or handl ing the birds. It is possible this can be accompl ished in most situations with a Questar field model telescope (80-130x). When band numbers cannot be discerned, attempts will be made to trap and examine the falcon at a time when capture wi 11 have least impact upon breeding activities. 4a. In accordance with an annual release plan developed and approved by the State, u.s. Fish and Wildlife Service, Bureau of Land Management, National Park Service, and the Forest Service, a predetermined number of wild breeding pairs will be manipulated to augment natural productivity. Pairs with a history of reduced clutch size, cracked eggs, or infertile or dead eggs will be candidates for fostering efforts. 4b. On occasion, it may be necessary to recycle several early breeding pairs in order to delay them until captive hatched young of the proper age are available for placement into wild sites. No later than 10 days after the last egg has been deposited, the eyrie will be visited and the entire clutch removed without replacement. Approximately 14 days after removal of the clutch, the pai r wi 11 recycle, select another nest ledge, and deposit a second clutch of eggs. If the eggs are.thin shelled, they may be replaced with plastic replicas and treated as outlined in approach 4a. This technique also works well to augment captive production with wild produced eggs. 4c. At times, pairs will select inferior eyrie ledges that may compromise nest success such as ledges that are too narrow to support a brood of large nestlings, the site may be vulnerable to predators, or it may be exposed to the elements. If the ledge cannot be mechanically improved, pairs can be relocated to other ledges through the recycling method described in approach 4b since they invariably relocate and select a new ledge when recycled. 5. In accordance with an annual release plan developed and approved by the State, U.S. Fish and Wildlife Service, Bureau of Land Management, National Park Service, and the Forest Service, a predetermined number of captive produced falcons will be released at unoccupied or potential sites through the technique of hacking. This technique is employed at locations that do not have the benefit of protection or care from adults. Young falcons of about 35 days of age will be placed in a hack box on a suitable cliff 1edge at the reint roduct ion site. They wi 11 be fed and cared for by attendants until they are flying and capable of fending for themselves. This technique assures that the young become familiar with their surroundings and hopefully will return to the site as adults and take up residency. Hacking requires constant attendance and observation to protect the vulnerable young and assure they have sufficient food while they are dependent upon the hack site. Whi 1e the hack sites wi 11 be �operated by the State, actual costs to operate the sites will be borne by the appropriate land administering agency (Forest Service, Bureau of Land Management, and National Park Service). 6. Confirmed breeding territories and selected potential breeding sites will be surveyed annually to document the presence of released falcons and ultimately determine the success of recovery efforts. RESULTS AND DISCUSSION Territory Occupancy Territory occupancy increased from 39 sites in 1989 to 44 in 1990 (Table 1). The expansion was due to reoccupancy of one historical site (site 12) and discovery of 7 previously unreported sites (sites 58 through 64). All the recently discovered sites were situated on cliffs that had been surveyed and found to be vacant in the past. West Slope nesting pairs continued to expand (Table 2) with 35 sites occupied by 33 breeding pairs. East Slope site occupancy increased to 9 sites with addition of a new pair (site 60). Reproduction Peregrine productivity in 1990 averaged 2.00 young fledged per successful pair (31 pairs fledged 62 young) and 1.55 young fledged per total pair (40 pairs fledged 62 young)(Table 3). The 35 occupied sites on the West Slope fledged 51 young (1.55 young per occupied territory) while the 9 East Slope sites produced 11 fledglings (1.22 young per occupied territory) (Table 2.). Six sites (sites 9, 16, 29, 34, 43 and 46) were manipulated to produce second clutches of eggs for release on the East Slope. In all 19 eggs were obtained and 15 young were hatched. The original female at site 46 was replaced and although the new female laid and incubated eggs, they failed to hatch. Site 43 produced a second clutch of eggs, put they also failed to hatch. The second clutch exhibited no signs of development. The other four the pairs produced 9 young (2.25 young per pair), but do to failure of sites 43 and 46, the manipulated sites averaged an overall productivity of 1.5 young. The 15 young that were hatched from the recycle effort were hacked to the wild at 3 East Slope sites. For the third year the adult male at site 39 was paired with a pralrle falcon. their nesting attempt failed. Although they frequented a particular ledge, there was no evidence that they produced eggs. Eggshell Condition Eggshell fragments representing 40 first clutch eggs originating from 17 wild nests were collected in 1990. Shell thickness (with membrane) averaged 9.9% thin (0.324 mm) which continues to be an improvement over eggshell thicknesses observed prior to 1989. Unfortunately, within clutch thicknesses continued to vary wildly. As an example, Site 9 produced eggshells that were +1.7%, -1.7%, �and -12.0% thin, respectively. Shells from two eggs collected at Site 31 were 0% and -18.4% thin. The poorest eggshells came from Site 43, which averaged 14.2, -16.7, and -17.5% thin (despite their condition, the two thinnest were hatched ;n captivity). The thinnest egg encountered was on the East Slope (site 2) and measured -19.8 % thin. Organochlorine Residue in Eggs Results of chlorinated hydrocarbon scans of 28 nonviable whole eggs encountered at wi ld nests from 1986 through 1989 have not yet been received. Eleven additional intact nonviable eggs were collected in 1990 and submitted to the Fish and Wildlife Service for analysis. Hacking Efforts Hacking efforts continued along the East Slope in order to bolster the wild population. In 1990, 15 falcons were released at 3 sites and 12 achieved independence (Table 4.) for a success rate of 80% (Table 5.). In 1990, the Fish and Wildlife Service did not apportion any of the Peregrine Fund's captive production for release in Colorado. The only way falcons could be obtained to augment East Slope production was through recycling wild breeding pairs. In all, 6 pairs (sites 9, 16,29,34, 43, and 46) were recycled. and 15 viable young were hatched from 19 eggs. All 15 falcons were returned to the wild through hacking. The hacking effort in downtown Denver was not activated in 1990. Although pair of falcons frequented the release site and although they did not breed, their territorial defense jeopardized any hacking effort. After the hack box at the Air Force Academy had been opened for a week, it was closed and a male that had been held back from the 1989 release due to impaired feather development, was placed in the box and re-released. The effort was unsuccessful and the male was picked up several days later suffering more feather damage and poor condition. He will be permanently retained in captivity. Return of Released Falcons In the course of 1990 field investigations, observers attempted to determine the presence of bands or color markers on territory occupying falcons. In all, 44 of 87 falcons were checked for the presence of bands or markers and 9 (20%) were marked. Prepared By: _ Gerald R. Craig Wildlife Researcher C �Table 1. OCCUPANCY OF PEREGRINE BREEDING TERRITORIES IN COLORADO SITE PRE NO. 1964 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1 2 3 4 5 6 7 8 P P P P P A A A M P P P ? P P P P P P P P M P V P P V V M V P P P P P P V V1 V P P P V V A V M P P P P P P P P P P P p V 9 + 11 V P P A 12 M V 13 + A 14 + V F P V 15 + 16 .t 17 t V 18 + V 19 + 20 + V A 22 23 + V --------------------------------------------------------(Historical 24 25 26 27 28 29 30 31 32 33 34 35 37 + 38 39 40 41 42 43 44 45 46 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 V V P P p V M V V Ps P V V V V V V A A V V P P V V F4 V V V V V V V V V V V V V V V V V V V A V V V V V V V P P P V V V V V V V V V1 V V V V P P P1 P2 P V V V M P V V V P V V1 P V V P P V V V V V V V V V P1 V, P V1 V V V P M M F V P7 V V F V V V P1 P V P V V V V P P V P P V V V V V P P F V V V V P V P P V V V V V V V V V V M V P V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V sites above P P P P P P P P P P ? V V V V, V V V V V V V V V V V V V V V V V with fenale prairie P P P P M P V V V V V P P P P P P P P V V V V V P, P V p6 P V V P P P P P P P V V V V V V P P P V V V V V V V P V V P P P P V V P P1 P V V V V V V V V V V V V V V V V V V V V V P V V V V V V V V V V V V P P V V V V V V P V P V P V P V V Y V Y V V V V V V F V V Y P V P V P V V V P P V P P P P V P V P V V P P V M P P P, P P P P, P Pg P P P P P P P P P V P V P P P P V V P P V V P P V V V V V P P P P V V P P P1 P P P, P P P V P P P P P P V P P1 P p P P V V P P V falcon. V P V V V this line)-----------------------------------------------------V V M V M V V V V P P P P P P V3 P M V V v V V Va P P F P M P P P V V V V M P V V V V V V V P A V P P P P P, P P P P P P P M P P P M P P P P P P P P P P P P, P P P V V V V A: Lone adult. F: Lone adult female. M: Lone adult male. p: Adult pair. V: Vacant site. 1 Ad. male & imm. female. 2:1&111. male & ad. fellale. 3:Ad. female replaced by il1l1. female midway. 4:Dead ad. female 5 Ad. male replaced by imm. male midway. 6:Ad. male dead in Vicinity. 7:18111. nale & fe;ale. 8:1mll. male. 9 Ad. male paired P V V V F V V P P P1 P P P P P P P P P, P2 P V P P Pg P V V V F found in vicinity. P P P P9 P P P P P P P P M P Pg P P P P V P V P P P ~9 P V P P P P P P P P V P P F V P P P P V P P P P P P P P �Table 2. COMPARISON OF EAST AND WEST SLOPE SITE OCCUPANCY CUM West Slo~e Occupled sites Breeding Pairs Young Produced Young Hacked 73 74 75 76 77 78 79 80 81 82 83 84 11 9 7 7 10 9 11 11 11 11 13 13 1 4 4 3 8 6 4 5 6 6 8 11 o 10 5 4 11 16 12 16 15 20 21 26 0 0 0 0 0 0 5 7 10 8 15 18 East Slo~e Occupled Sites Breeding Pairs Young Produced Young Hacked 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 CUM 3 2 1 1 2 2 2 2 0 0 1 1 1 2 5 8 7 9 3 2 1 1 1 0 0 0 0 0 0 1 1 1 3 2 4 6 2 3 0 3 0 0 0 0 0 0 0 3 2 2 10 5 6 11 47 0 0 0 0 0 4 5 4 3 5 8 9 12 10 19 26 25 12 110 85 86 87 88 89 90 13 19 24 24 32 35 12 17 20 22 27 33 26 32 45 44 60 51 12 4 0 0 0 0 360 79 �Site 1 2 3 4 5 7 9 11 12 16 18 25 27 29 30 31 32 33 34 35 38 39 40 42 43 44 45 46 47 48 49 50 52 53 54 55 57 58 59 60 61 62 63 64 Table 3. Summary of 1990 Peregrine Production Age Eggs Young Young Male Female 1st 2nd Hatched Fostered Clutch Clutch A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A I A A A A A A A A A A A A * A A A A A A A A A A A A A A A A A A A A A A A I A A A A A A 1+ 2+ 4 1 3 3 2+ o a o 2 1+ 3+ 2 2+ 1 3+ Young Fledged 3 3 1+ 3+ 3 2 o a 4 3 3 3 2 3 2 2 2 2 3 2 3 3+ 2 3 3+ 3+ 2 2+ 4 o 3 4 1 2+ 2 2 3 3 3 a o 2+ 1 3 1 3 1+ 2+ 2+ 2 1+ 3 4 3 3 4 4 3 4 3 3+ 3 + 1 a o 3 3 2+ 2+ 1 3 3 3 1+ 1+ 1 1 2+ 1+ 2+ 3+ o o o a 2+ 1+ 1 2 3 2 o o o 1+ 1+ 1+ 1+ 3+ 3+ 1+ 1+ 91+ o o 14+ 73+ 1 1 3 1 o 62 Total Sites Occupied: 44 Total Adult Pairs: 40 Total Breeding Pairs: 37 Total Successful Pairs: 31 Total Young Produced: 73+ Total Young Fledged: 62 Average Fledged Brood Size:2.001 Young Fledged Per lotal Pair: 1.55 Young Fledged Per Total Unmanipulated Pair: 1.55 * Total Fledglings Divided by Total Successful Paired with female prairie falcon. Pairs. �Table 4. Site Name Air Force Academy Twin Mountain Deer Mountain TOTAL 1990 HACKING RESULTS Supporting Agency Young Released Young Achieving Independence USFS BLM NPS 5 5 5 4 15 3 5 12 �Table 5. Site Sheep Mtn. Hermosa Conejos II Perins Peak Chimney Rock Moraine Park Deer Lodre Conejos Wolf Creek Beaver Creek Royal Gorge Big Hole Adobe Peak Deer Mtn. Twin Mtn. Natural Arch Trout Creek Denver Academy TOTAL SUCCESS 1978 1979 1980 1981 5/4 5/5 5/5 -- 4/4 --- ------------------5/4 80% --- --------------- -- 4/3 4/4 ---------------- 4/4 3/3 3/3 3/3 -------------- COLORADO HACK SITE SUCCESSES 1918-90 1982 1983 1984 1985 1986 1987 1988 1989 1990 5/5 -- 4/4 --- 5/5 --5/5 -- 5/5 -- 3/3 ------- ------------ --------- -------------- --- -5/3 4/4 4/0 -- 4/0 5/4 4/4 4/4 4/4 4/4 ------------- -- ---------- 4/4 4/3 -- 5/2 5/5 5/4 4/4 ---------- 5/2 -- 5/4 5/3 515 5/0 ---- ------ -3/1 ---- -3/3 ---5/5 4/3 4/1 4/3 4/4 3/3 -- ---- ---- -- SIS 4/2 ----- 5/4 5/0 5/4 4/4 4/4 SIS 5/5 -- 10/10 12/11 13/13 22/13 25/23 32/27 35/24 20~14 22/19 33~26 100% 92% 100% 59% 92% 84% 69% 0% 86% 9% -- 4/2 ---- 4/3 5/5 4/4 515 5/3 3/3 5/5 5/3 ---- 5/4 31/25 15/~ 81% 8 '\ TOTAL SUCCESS 36/35 8/7 28/24 11/6 8/5 13/6 22/20 14/11 25/23 5/0 13/10 13/5 19/17 18/14 8/8 10/10 10/8 8/7 97% 100% 87% 86% 54% 62% 46% 91% 78% 92% 0% 77% 38% 89% 78% 100% 100% 80% 88% 274/221 81% SIS ��13 JOB PROGRESS REPORT State of Project: ~C~o~l~o~r=a=do=_ _ ~(=W-_1~5~1~-~R_-~3)~ _ Bald Eagle Nest Site Protection and Enhancement Program Period Covered: 1 July, 1989 - 30 June, 1990 Personnel: G.R. Craig, Colorado Division of Wildlife and R.L. Knight, Colorado State University. ABSTRACT Although 10 Colorado territories were occupied by breeding bald eagles once again in 1990, one of the 1989 territories was abandoned and a new pair was discovered in La Plata County. Productivity was 1.3 young per nesting attempt. Attrition to windthrow continued with loss of one nest in Rio Blanco County. Due to scheduling difficulties and hazardous placement of several nests, only 2 sites were visited during the nestling phase and only 4 young were banded and color marked. This Job Progress Report represents a preliminary analysis and is subject to change. For this reason, information presented herein MAY NOT BE PUBLISHED OR QUOTED without permission of the author. ��15 BALD EAGLE NEST SITE PROTECTION AND ENHANCEMENT PROGRAM Gerald R. Craig SEGMENT OBJECTIVES 1. Monitor nest site occupancy and reproductive success. 2. Document survival rates and mortality factors. 3. Determine migration and wintering areas. 4. Determine if philopatry occurs in breeding eagles. 5. Determine nest site tenacity by individual breeding eagles. 6. Quantify nesting habitats and associated foraging areas in an effort to document nest site parameters conducive to improved reproduction. 7. Document pesticide contamination through eggshell measurement and chemical analysis of nonviable eggs. 8. Where necessary, occupancy. implement actions to stabilize nests and maintain METHODS AND MATERIALS This work will be a cooperative endeavor between the Division and Dr. Richard Knight of Colorado State University. 1. Annually visit all documented breeding sites to determine the presence of bald eagles. Pairs at territories will be documented by DWMs and other field personnel. Previously unrecorded pairs will probably be revealed in the course of aerial eagle and waterfowl flights. DWMs will confirm actual incubation from ground visits. 2. Occupied territories will be visited by DWMs periodically throughout thebreeding season to determine hatch of young, nesting failures, etc. 3. In May and June, a Util ity Worker wi 11 observe breeding eagles from a distance and endeavor to follow thei r movements to locate important foraging areas. Responses of eagles to various human activities and land uses will be recorded. 4. In June, when the young are determined to be old enough to band, sites will be visited by Craig and Knight to place a federal band on one leg and a colored, alpha numeric marker on the other. The color markers will permit identification if the young return in subsequent years. During the same nest visit the following will be recorded: Physical parameters such as tree species, height, DBH, condition, and dominance. Nest condition, size, and location. Vegetative community and land use practices. �16 In addition, collect prey remains, nonviable eggs and eggshell fragments. 5. When necessary, remedial actions will be taken to stabilize nests that are threatened by wind throw. Should the tree be decadent and in danger of falling, an artificial nest base may be placed in a suitable, adjacent tree. Action will be taken only after it has been deemed desirable to encourage the eagles to nest at the same location. RESULTS AND DISCUSSION Territory Occupancy Bald eagle nesting activities for Colorado are summarized in Table 1. In 1990, 10 territories (Adams, La Plata #1 and #3, Moffat #1, and #2, Montezuma #2 and #3, Rio Blanco #1 and #3, and Weld #1) were occupied. The pair that first occupied Weld #2 in 1989 did not return in 1990. However, Weld #1 was occupied which suggests that the pair may alternate between the two sites. After several years of search, a new pair was discovered at La Plata #3. As far back as 1978, adult eagles were intermittently observed in the region throughout the summer, but nesting was not confirmed. The nest was located in an old growth ponderosa pine secluded in the bottom of a forested canyon. Land Status The territory of La Plata #3 is on U.S. Forest Service land. As reported previously, (Craig 1988) Weld #1 occupies private property. The landowner is aware of the site and is protect ive of the pair. Land use in the area is livestock ranching. Reproduction Reproductive efforts of the 10 pairs are summarized in Table 2. In all, 15 young were hatched by 10 pairs (1.5 young per pair), 13 young were fledged by 8 pairs (1.62 young per successful pair) which yielded an overall productivity of 1.3 young per nesting attempt. Both young that were lost died at 5 to 6 weeks of age of undetermined causes. Unlike the previous year, no broods of 3 young were observed. Because of scheduling difficulties, 5 sites (La Plata #1 and #3, Montezuma #2 and #3 and Weld #1) were not visited during the nestling phase. Nests at Moffat #1, Rio Blanco #1 and #3 were too precarious to cl imb without endangering the cl imber and the nest, so no data were obtained. As a result, two sites (Adams and Moffat #2) were visited to band nest 1ings and co11ect eggshe 11 fragments. On 1y 4 nestlings were marked with an unanodized aluminum U.S. Fish and Wildlife Service band on the left leg. A red anodized band with vinyl yellow tag affixed was attached to the right leg. Blood samples, culmen length and foot pad length measurements were obtained from the 4 eaglets. �17 Eggshell Condition Due to the minimal number of nest visits, no nonviable eggs or eggshell fragments were encountered in 1990. Nest Stabilization Efforts In the fall of 1989, the nest at Rio Blanco #3 was reported blown down. Upon inspection, it was determined that the entire main trunk had broken. An artificial nest platform was constructed one of the remaining forks of the same tree. The original nest materials were hoisted and placed in the new structure. Weight of the old nest was 280 lbs. Several groups of eggshell fragments were encountered in the old nest cup and were retained for thickness measurement. Artificial nest platforms at Adams, and Montezuma #3 continued to be used. The pair at Moffat #1 again used the extremely vulnerable nest they selected in 1989. If at all possible, an artificial nest should be constructed in an adjacent tree and the present nest should be removed. This nest is in a dead tree top and will be lost to windthrow in the near future. Should windthrow occur during the spring or summer, that pair's reproduction will be lost. Inspection broken and the Fall, additional of the platform at the Adams site revealed that a support wire had the additional mass of the nest required remedial stabilization. In the site will be visited to install plastiC coated cable and add supports. LITERATURE CITED Craig, G.R. and R.L. Knight 1989. Bald Eagle nest site protection and enhancement program. Job Prog. Rep., Colo. Div. Wildl. Res. Rep., Jan., pp1-7. Craig, G.R. 1988. Bald Eagle nest site protection and enhancement program. Job Prog. Rep., Colo. Div. Wildl. Res. Rep., Jan., pp1-6. Prepared by: c;~__Ic2 __ ~~~~ Gerald R. Cr i Wildlife Researc er C _ �r' co Table 1. Bald Eagle Nesting Efforts in Colorado Site 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 La Plata Co. #1 Moffat Co. #1 La Plata Co. #2 Grand Co. Montezuma Co. #1 Rio Blanco Co. #1 Rio Blanco Co. #3 Weld Co. #1 Montezuma Co. #2 Moffat Co. #2 Moffat Co. #3 Adams Co. Archuleta Co. Montezuma Co. #3 Weld Co. #2 La Plata Co. #3 1egg IA IA IA IA 1yng 2yng 2yng 2yng 2yng 2yng 2yng Oyng o 1 A ? ? ? -IA IA 2yng IA IA' A 1yng 2yng IA IA A 1yng 3yng A Total Young Total Pairs IA = Inactive IA 1yng Oyng Oyng = 1 1 Active 4 4 2 2 4 3 1 3 o 1 3 3 6 4 ? -IA IA A ? 2yng IA IA IA ? eggs 2yng 2yng 2yng 2 6 2 4 ? Oyng IA IA IA Oyng 2yng 2yng 2yng 6 5 eggs 1yng IA IA IA 2yng Oyng eggs 1yng 1yng 1egg eggs eggs 5 10 2yng 2yng A IA IA 2yng 1yng IA 1yng Oyng IA 1egg 2yng 10 9 1yng 1yng IA IA IA 2yng A IA 1yng 2yng 2yng 3yng IA IA IA 2yng 2yng IA 1yng 3yng ? eggs eggs 2yng IA IA 1yng 1yng eggs 8 8 16 10 Oyng 2yng IA IA IA 2yng 1yng Oyng 1yng 2yng IA 2yng IA 1yng IA 2yng 13 10 �19 Table 2. Colorado Bald Eagle Nesting Efforts - 1990 Age of Birds Male Female Site Young Produced Young Fledged Adams Co. Adult Adult 2 2 La Plata Co. #1 Adult Adult 0 0 La Plata Co. Adult Adult 2 2 Moffat Co. #1 Adult Adult 2 2 Moffat Co. #2 Adult Adult 2 2 Montezuma Co. #2 Adult Adult 2 1 Montezuma Co. Adult Adult 1 Rio Blanco Co. #1 Adult Adult 2 2 Rio Blanco Co. Adult Adult Adult Adult 1 0 10 10 15 13 Weld Co. ttl Total #3 #3 #3 Comments Half feathered young dead in nest. �JOB PROGRESS REPORT State of ~C~o~l~o~r=a~d~o _ Project: (W-156-R-1) Period Covered: 1 July, 1989 - 30 June, 1990 : Pawnee Grasslands Raptors Personnel: G.R. Craig, Colorado Division of Wildlife and Douglas G. Leslie, Colorado State University ABSTRACT Original 1972 field notes were obtained from R.R. Olendorff and field work was initiated on the same study area originally delineated by Olendorff. The cumulative number of nesting raptors increased from 158 in 1972 to 235 in 1990. The 33% increase primarily resulted from a doubling of the number of nesting Swainson's hawks and great horned owls. Site parameters and habitat features were recorded for each nest site. This Job Progress Report represents a preliminary analysis and is subject to change. For this reason, information presented herein MAY NOT BE PUBLISHED OR QUOTED without permission of the author. ��PAWNEE GRASSLANDS RAPTORS Gerald R. Craig and Douglas G. Leslie SEGMENT OBJECTIVES 1. Describe the summer raptor community on the Pawnee National Grassland including species richness, relative abundance, distribution, reproductive effort, and food habits. 2. Describe the habitat and nest-site structure use of this raptor community. 3. Compare objectives 1 and 2 with similar information collected for this raptor community 2 decades earlier. 4. Document the effects,if any, of recreational activity, grazing and mineral development on raptor productivity, and habitat and nest-site usage. METHODS AND MATERIALS a. Study Area The study area will be the same as used by Jameson and Bement (1969) and Olendorff (1972). This is a 1,073 km2 site of mixed (private and USFS) ownership. Geographically, the site corresponds to the western portion of the Pawnee National Grassland and includes 111/2 townships. The area is part of the shortgrass prai rie biome, however, parts of it are in agricultural crops. Areas to the west and south are in winter wheat while on the east is a large creek bottom with nearly continuous band of cottonwoods (Popu7os spp.) and other riparian plants. The north is bounded by a band of bluffs. Bluffs, large creeks, and large tracts of cultivated land do not occur inside the study area. The IBP Pawnee Site and the Central Plains Experimental Range are near the northwest corner of the site. In addition to the intensive study area, we will examine raptors nesting on f larger area that Olendorff (1972) also used. This site is 5870 km and comprises the northern portion of Weld County, Colorado. b. Methods 1. The study area will be divided into townships and searched on foot and with vehicles (i.e., truck and motorcycle) for nests and eyries. Nests and sightings will be plotted on detailed maps of the study area. Active nests will be monitored until their reproductive fate is determined. Nests will be visited to band young and determine food habits. 2. At each nest a series of nest and nest structure characteristics will be measured (Table 1). In the vicinity of each nest a series of vegetation and human variables will be measured (Table 1). This information will be compared with similar measurements collected by Olendorff and others 2 decades earlier. In addition, geographical information systems (GIS) technology will be used to document land use changes during this time and �compare this information with abundance and distribution. 3. the present and past raptor species Efforts will be made to examine whether recreational activity, livestock grazing or mineral development effect raptor reproductive success by looking for correlations between nesting success and proximity to the developments. c. Analysis 1. Species richness, relative abundance, and food habit information will be presented qua 1itat ive 1y. This informat ion wi 11 be contrasted with s imilar data collected 2 decades earlier. Distribution patterns will be analyzed using spatial statistics. Reproductive success will be analyzed using a modified Mayfield estimator (Steenhoff and Kochert 1982). 2. A GIS software package (program PMAP) will be used to compare raptor distribution and land use changes over the 2 decade period. 3. Stepwise multiple regression analysis and logistic regression analysis will be used to examine whether recreational activity, grazing or mineral development effect raptor reproductive success. For stepwise multiple regression analysis, the dependent variable will be the number of young fledged and the independent variables will be those listed in Table 1. For the logistic regression analysis, the dependent variable will be success or failure of the nest (regardless of the number of young fledged) and the independent variables will be those listed in Table 1. RESULTS AND DISCUSSION Olendorff's original field notes for 1972 were obtained and duplicated. The study area was resurveyed and all nesting raptors were inventoried (Table 1.). The number of nesting Swainson's hawks (Buteo swainsonii) and great horned owls (Bubo vi rginianus) nearly doubled and red-tailed hawk (Buteo jamiacensis) breeding pair tripled. Ferruginous hawk(Buteo regal is) pairs fell by half. The actual nesting status of prairie falcons (Falco mexicanus) and golden eagles (Aquila chrysaetos) remained uncertain since a significant population occupied the Eagle Rock Ranch and access was denied in 1990. Habitat data and productivity for all nesting raptors was recorded. A suitable database structure was formulated and data entered. Digitizing of nest locations, roads, houses and other geographic data into the ARC/INFO geographic information system will be accomplished in the next segment. LITERATURE CITED Jameson, D.A. and R.E. Bement. 1969. General description of the Pawnee site. USIBP Tech. Rept. 1. Colo. State Univ., Fort Collins, CO 24pp. Olendorff, R.R. 1973. The ecology of the nesting birds of prey of northeastern Colorado. U.S. IBP Grassland Biome Tech. Rep. No. 211. 233p. �Steenhoff, K. and M.N. Kochert. 1982. An evaluation of methods used to estimate raptor nesting success. J. Wildl. Manage. 46:885-893. Prepared By: _ Gerald R. Craig Wildlife Researcher C �Table 1. Variables to be measured in the vicinity of raptor nests in the Pawnee National Grasslands Nest-Site And Structure Variables Nest structure type (if tree, species; if cliff, geology) Nest height Nest structure height Nest elevation Nest relief Nest aspect Nest structure aspect Nest cliff length (for cliffs) Nest cliff area (for cliffs) Nest cliff verticality (for cliffs) Diameter breast height (for trees) Diameter nest height (for trees) Nest opening width (for cliffs) Human Disturbance Variables Linear distance from nest to nearest human dwelling, to nearest community Pavement distance from nest to nearest human dwelling, to nearest community Pavement time from nearest human dwelling, to nearest community Foot distance from nearest road to nest Number of roads within 5 km radius from nest Linear distance from nest to nearest paved road Linear distance from nest to nearest road of any nature Land use within a 5 km radius of the nest. �Table 2. Comparison of occupancy and productivity of six species of raptors inhabiting the Pawnee National Grasslands in 1972 and 1990. Species No. of Pairs 1972 1990 % Successful Pairs 1972 1990 Young Fledged 1972 1990 Swainson's Hawk 68 151 56.8 49.7 80 152 Ferruginous Hawk 26 16 61.6 43.8 48 15 Red-tailed Hawk 8 24 62.5 8 26 Great Horned Owl 30.5 64 29.1 60.9 18 75 Golden Eagle 12 6 41.6 50.0 6 4 Prairie Falcon 14 6 78.6 83.3 41 15 ? � https://cpw.cvlcollections.org/files/original/16b2f9b4ac09de45d0f33b1c1dbdf2ac.pdf 57bdeaf8b26a7b98b18e72707c3fc2b5 PDF Text Text .•.1 JOB PROGRESS REPORT State of: Colorado Project: __~W_-~1~5~2_-~R~ _ Work Plan: 3__ : Job Job Title: Sage Grouse Band Recovery 13a Period Covered: 01 January Author: A. Zablan Marilet Personnel: Upland Bird Research Analysis through 31 December and Survival Estimation 1989 C. E. Braun, Colorado Division of Wildlife; Zablan, Colorado State University G. C. White, M. A. ABSTRACT Survival estimates were calculated for sage grouse (Centrocercus urophasianus) using program BROWNIE for males and program ESTIMATE for females. Survival rate estimates for males banded and released as yearlings (young) ranged from 15.0% (95% confidence interval: 0-37.5%) in 1986 to 100% (27.3-100%) in 1974. The mean survival rate estimate of males banded as yearlings was 51.7% (40.063.3%). Survival rate estimates for males banded and released as adults ranged from 0% (0-19.9%) in 1985 to 84.6% (33.8-100%) in 1979 and averaged 38.4% (32.9-43.8%). Since no differences in survival rate estimates were detected between females banded as yearlings and adults, the data were pooled. Survival rate estimates for females did not differ by year (f - 0.47). The survival rate estimate for females was 54.2% (standard error - 2.42, 95% confidence interval - 49.5-59.0%). A preliminary analysis with survival as a function of harvest regulations was conducted for females. Addition of harvest regulation information did not significantly improve the goodness-offit and the simplest model (constant survival and recovery) adequately described the data. ��.) .) SAGE GROUSE SURVIVAL ESTIMATION, NORTH PARK, COLORADO Marilet A. Zablan SEGMENT OBJECTIVES 1. Analyze sage grouse banding data. 2. Monitor sage grouse population 3. Estimate annual survival rates by age and sex class from band recovery and recapture data from 1973 through 1989. 4. Extend analyses of recovery and recapture 5. Develop models from band recovery data with survival as a function available weather variables. 6. Extend the analysis of band recovery data for upland game birds. 7. Collect sage grouse harvest data. 8. Present findings at appropriate 9. Compile and analyze data and prepare quarterly size and weather variables. management data of birds. and scientific of meetings. and annual reports. METHODS A database was created using the "dBASE II" database management software package. The following information was entered for each recapture (live) and/or recovery (dead) of a sage grouse banded in North Park, Colorado from 1973 through 1988: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. band number, date banded, age when banded, sex, site where banded (verbatim from banding form), North Park quadrant where banded (l=NW, 2=NE, 3=SE, 4=SW), section where banded, range (west) where banded, township (north) where banded, date when recaptured or recovered, age when recaptured or recovered, site where recovered or recaptured (verbatim from recovery North Park quadrant where recaptured or recovered, section where recaptured or recovered, range (west) where recaptured or recovered, township (north) where recaptured or recovered, whether bird was recaptured or recovered, method of recovery (for dead birds only), and whether or not bird was radio-marked. file), There were 1,467 different entries including recaptures and recoveries from 1973 through 1989. The database file created in dBASE II was converted into a dBASE III Plus file. �The data base was reviewed and missing, incomplete, or incorrectly entered data were noted. I reviewed the database with C. E. Braun (Colo. Div. Wildl.) and, in addition to clarifying locations of many of the recaptures and recoveries, an age-classification scheme for assigning ages of birds when recaptured or recovered was devised (Table 1). Additional recovery data (1989) obtained through use of check stations, volunteer wing collection barrels, and mail-in returns will be entered into the database. Table 1. Age classification of sage grouse banded, recaptured, or recovered. Bird banded as Will be classified If recovered during 11- 1+ 2+ 1st fall (01 Aug-3l Oct) 2nd spring (01 Nov-3l Jul) 2+ 2+ 1st fall 2nd spring 2+ 3+ 1st fall 2nd spring etc. 1+ 1+ etc. 2+ 2+ etc. The recapture/recovery database was transferred to the "dBASE III Plus" database management software package. Within dBASE III Plus, programs were written to convert dates (date banded, date recaptured or recovered) to an acceptable format for analysis. Program SAS was not used to edit the database, as applications in dBASE III Plus were acceptable. Programs SAS (SAS Inst. 1985) and SURVIV (White 1983) were used for data summary and analysis. Ages at banding and recapture/recovery were converted to decimal values (e.g., from 1- to 0.9, from 1+ to 1.2, from 2+ to 2.2, etc.) for ease of data summary and analysis. Of the 1,467 different entries for 1973 through spring 1988 including recaptures and hunting season recoveries, 2 entries were deleted for lack of banding data. Total banding data (1973-88) were summarized. This summary consists of total number of birds banded per year by age and sex as these data are needed to operate programs such as BROWNIE and ESTIMATE. Climatological data for North Park (Walden and Spicer weather stations) were summarized. Precipitation and temperature data for 1973-89 (Jan-Jul) were included, for future inclusion in survival models. Program SAS was used to summarize the North Park sage grouse recovery information by sex and year. Numbers of grouse banded by age and sex varied (Table 2). Recovery matrices were generated (Tables 3-6) and used as input for FORTRAN program BROWNIE. The 1988 recovery data were summarized and added to the database after the analyses were conducted. �Table 2. Sage grouse banding data, North Park, Colorado, 1973-88. 3umber banded Year 1- Males 2+ 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 88 54 138 120 183 106 111 127 110 110 152 102 163 104 117 ll5 99 88 153 114 123 98 146 173 190 190 157 92 88 51 85 88 Table 3. Colorado, Recoveries 1973-87. All 1- 179 142 291 234 306 204 257 300 300 300 309 194 251 155 202 203 41 22 62 71 101 32 48 72 31 42 33 123 46 33 71 48 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 68 27 68 74 133 22 52 94 38 69 32 III 28 30 29 59 of adult male sage grouse by hunting Recoveries Year banded Females 2+ All Totals 109 49 130 145 234 54 100 166 69 101 65 234 74 63 100 107 288 191 421 379 540 258 357 466 369 401 374 428 325 218 302 310 season, North Park, bX hunting; season 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 7 4 8 1 5 10 0 1 4 16 1 0 2 3 12 0 0 0 2 3 10 0 0 1 0 2 9 14 0 0 1 0 3 3 9 9 0 0 0 0 0 0 3 5 16 0 0 0 0 0 0 3 2 5 19 0 0 0 0 0 0 0 1 2 6 15 0 0 0 0 0 0 0 0 0 2 3 8 0 0 0 0 0 0 0 1 1 1 0 5 10 0 0 0 0 0 0 0 0 0 0 0 1 1 8 0 0 0 0 0 0 0 0 0 1 0 0 0 1 10 �6 Table 4. Recoveries of yearling Park, Colorado, 1973-87. male sage grouse by hunting Recoveries Year banded 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 bX hunting 73 74 75 76 77 78 79 80 6 4 6 6 5 18 1 2 6 17 0 1 6 5 20 1 0 2 6 9 0 0 0 2 6 0 0 1 1 2 3 14 4 13 4 13 81 0 0 0 1 1 1 0 5 13 season 82 0 0 0 0 1 0 1 3 5 7 83 84 85 0 0 0 0 0 0 0 1 4 1 15 0 0 0 0 0 0 0 0 0 3 10 12 0 0 0 0 0 0 0 0 0 1 2 Recoveries 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 4 16 Table 5. Recoveries of adult female sage grouse by hunting Park, Colorado, 1973-87. Year banded season, North 73 74 75 5 1 2 0 0 6 76 1 0 2 2 77 1 1 4 2 15 bX hunting 86 0 0 0 0 0 0 0 0 0 1 0 0 4 5 87 0 0 0 0 0 0 0 0 0 0 0 0 1 2 8 season, North season 78 79 80 81 82 83 84 85 86 87 0 0 1 0 0 1 3 5 0 3 0 0 0 0 1 0 3 7 0 0 0 1 1 0 0 5 0 0 0 0 0 0 0 2 1 5 0 0 0 0 1 0 0 2 0 2 1 0 0 0 0 1 0 1 0 0 0 1 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 2 2 1 0 0 0 0 0 0 0 0 1 1 0 0 0 1 6 1 3 1 4 2 1 4 1 �Table 6. Recoveries of yearling Park, Colorado, 1973-87. female sage grouse by hunting Recoveries Year banded 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 bX hunting season, North season 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 2 2 1 4 2 6 1 1 2 2 2 0 1 4 7 0 0 2 2 6 5 0 0 0 0 0 0 1 1 4 8 0 0 0 1 0 0 0 4 4 0 0 0 0 1 0 0 1 3 2 0 0 0 0 1 0 1 2 0 0 0 0 0 0 0 0 0 0 2 2 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7 6 0 0 2 1 3 0 0 0 1 6 0 7 0 1 0 2 4 1 8 Brownie et a1. (1985) presented band recovery models for birds banded as young and adults. The models were presented as hypotheses with certain assumptions about the relationship of the band recovery data to the actual population: Hvpothesis Ho 1) Young and adults have identical survival (fi); and 2) survival, hunting, specific. Hxpothesis reporting, (Si) and recovery and hence recovery, rates are year- Hal 1) Annual recovery and survival rates are age-dependent year of life only; and 2) annual recovery and survival rates are otherwise to year. Hxpothesis rates for the first constant from year H02 1) Annual reporting year-specific; and harvest rates (and hence recovery 2) annual survival and harvest rates are age-dependent year of life only; and 3) annual survival rates are otherwise constant rates) are for the first from year to year. �8 Hypothesis Hi 1) Annual survival, reporting, are year-specific; 2) annual survival and harvest rates are age-dependent for the first year of life only (i.e., young and adult birds have different survival and harvest rates); and 3) reporting Hypothesis and harvest rates are not dependent rates (hence recovery rates) on time of release. H2 1) Annual survival, harvest, and reporting rates are year-specific; 2) annual survival and harvest year of life only; and 3) in any year, the reporting rate for newly released birds is different from that for survivors of previous releases. rates are age-dependent for the first (H2 is an extension of Hi in that the first year adult recovery rate in year I is different from the recovery rate in year I of previously banded adults. (The soliciting of bands from hunters by conservation officers near banding sites may give rise to this situation.)] Hypothesis H3 1) Annual survival and recovery rates are age-dependent for the first 2 years of life (i.e., are different for young, subadults, and older birds). This embraces assumption 3 of model H2 for the experimental situation we are concerned with, because of the unidentifiability of the reporting rate; and 2) annual survival and recovery rates are year-specific. (H3 assumes the parameters Sand f are age-specific for 3 age classes (young, subadult, adult), but only 2 age classes are recognized during banding, because subadults and adults are usually indistinguishable.] Program BROWNIE (Brownie et al. 1985) was used to analyze the sage grouse band recovery data from North Park, Colorado for 1973-87. Survival estimates were calculated using programs BROWNIE and ESTIMATE (Brownie et al. 1985). Program SURVIV (White 1983) was used to model survival as a function of harvest regulations (Table 7). Harvest regulations were quantified as an index, the theoretical maximum bag possible for 1 hunter (i.e., season length (days) x maximum number of birds per day). For example, in 1987 the theoretical maximum bag possible was 23 days x 3 birds per day - 69 birds, while in 1973, it was 3 days x 2 birds per day = 6 birds. Appropriate cell probability functions were assigned in program SURVIV. �9 Table 7. 1973-89. Sage grouse season length and bag limits, North Park, Colorado, Years Season length (days) Bag/possession limit Maximum bag per hunter 1973-74 1975 1976 1977-80 1981 1982-84 1985-88 1989 3 9 9 16 23 30 23 30 2/4 2/4 3/6 3/6 3/6 3/6 3/6 3/6 6 18 27 48 69 90 69 90 Changes in harvest regulations were incorporated into the user-specified cell probability functions for survival rate estimation with program SURVIV (White 1983). The maximum bag possible (Table 7) was incorporated as a covariate in a logistic model: where Si was a function of the parameters possible in a given season. ~o and ~l' and Hi, the maximum bag The following models were tested for females with program SURVIV: Model 3, constant annual survival and band recovery rates; Model 2, constant annual survival rate and year-specific band-recovery rates; and Model H, similar to Model 2, but changes in harvest regulations were incorporated. Model 3 was the simplest model tested with only 2 parameters estimated, while Model H was the most general model tested. RESULTS The null hypothesis that adult males and females had the same recovery and survival rates was rejected (f - 0.013) with program BROWNIE (Brownie et al 1985) (Table 8). Closer examination of the data (Table 8) revealed that, although a difference was found hetween male and female parameters, this difference was not constant over years. Survival rates for males differed by year (f - 0.007) and statistical tests of different models indicated that Model Hl (Brownie et al. 1985) fit the data for males (Table 9). The assumptions of Model Hl are: �10 Table 8. Contingency chi-square grouse, North Park, Colorado. Matrix Year 1 2 3 4 5 6 Contingency table 8 9 10 11 12 13 14 15 due to sex of sage Matrix 1 X2 statistic with 1 d.f. 2 x2 Contingency table statistic with 1 d. f. 13 8 86 60 0.068 14 3 74 24 0.378 18 14 135 54 2.960 6 21 93 65 l.311 21 5 10 9 15 8.887 20 27 103 106 0.696 18 23 12 19 0.196 22 76 21 15 3.717 6 19 14 1.056 117 45 l.056 26 12 22 7 9 0.052 18 16 155 78 2.400 25 11 15 14 2.131 24 7 166 31 0.903 24 11 15 10 0.471 29 10 161 59 29 0.023 15 12 3.784 18 3 139 29 0.118 9 9 4.713 14 12 99 0.875 9 10 12 0.820 11 3 77 25 0.064 18 8 3 7 4.573 9 2 42 28 10 l. 941 2 3 0.788 10 75 23 l.428 1 7 test for differences 29 Total chi-square = 6 5 3 0.151 8 3 0.189 10 11 2.833 12 3 16 8 24 78 6 7 6 13 48.58 with 29 d.f., f(X2 6 > 48.58) ~ 0.013 �11 Table 9. Statistical tests of models grouse, North Park, Colorado. Chi-sguare Model 75.49 75.85 34.34 19.46 Ho vs Hl Hl vs Hz Hz vs H3 Case HOl vs Hoz Hoz vs Hl program BROWNIE, of fit tests d.f. Z calculated X sage XZ calculated) 0.073 0.011 0.268 0.303 59 50 30 17 not done tests between d.f. 41.16 14.88 15.45 Likelihood ratio XZ calculated 27.57 46.78 male f(xZ > not done Chi-sguare Case goodness Z X calculated Ho Hoz Hl Hz H3 under models P(Xz 0.067 0.315 0.280 29 13 13 tests between d.f. 28 26 > XZ calculated) models P(Xz > XZ calculated) 0.487 0.007 �12 1) annual survival, reporting, are year-specific, and harvest 2) annual survival and harvest rates are age-dependent for the first year of life only (i.e., young and adult birds have different survival and harvest rates), and 3) reporting rates are not dependent For females, band recovery Model Ho2 are: rates (hence recovery on time of release. data fit Model Ho2 (Table 10). 1) annual reporting specific, and harvest 2) annual survival and harvest year of life only, and 3) annual survival rates) The assumptions of rates (hence recovery rates) are year- rates are age-dependent for the first rates are otherwise constant from year-to-year. Survival estimates were calculated using programs BROWNIE (males) and ESTIMATE (females). Survival rates for males (Table 11) banded and released as yearlings (young) ranged from 15.0% (95% confidence interval, 0-37.5%) in 1986 to 100% (27.3-100%) in 1974. Mean survival of males banded as yearlings was 51.7% (40.0-63.3%). Survival rates for males banded and released as adults (Table 12) ranged from 0% (0-19.9%) in 1985 to 84.6% (33.8-100%) in 1979 and averaged 38.4% (32.9-43.8%). Since no differences in survival estimates were detected between females banded as yearlings and adults (Table 10), the data were pooled. Survival rates for females did not differ by year (f - 0.47). The survival rate for females was 54.2% (standard error - 2.42, 95% confidence interval ~ 49.5-59.0%). A preliminary analysis incorporating year-specific harvest regulations into survival models was conducted for females. Testing of 3 models under program SURVIV showed that the simplest model (3) was adequate to describe the data, and that the parameters added under Models 2 and H did not significantly improve the goodness-of-fit (Table 13). Both the relatively high goodness-offit under Model 3 (0.918) and the relatively low value of the Akaike Information Criterion (-2 x log-likelihood + 2 x number of parameters estimated - 280.041) indicate that Model 3 was the most appropriate model tested. While the results obtained with program SURVIV may have been expected to occur with the female data (Model H02 was earlier found to be appropriate), the results of model testing with the unpooled male data may be quite different and will be investigated. �13 Table 10. Statistical tests of models under program grouse, North Park, Colorado. Model Chi-sguare 2 calculated X Ha Ha2 Hl H2 H3 53.63 35.61 23.91 17.35 not done Case Ha vs Hl Hl vs H2 H2 vs H3 Case Hal vs H02 H02 vs Hl Chi-sguare X2 calculated 29.72 6.56 16.89 goodness of fit tests d.f. tests between d.f. 0.602 0.581 0.686 0.289 not done models f(X2 > X2 calculated) 0.428 0.923 0.204 29 13 13 28 26 female sage f(X2 > X2 calculated) 57 38 28 15 Likelihood ratio tests between X2 calculated d. f. 30.94 25.93 BROWNIE, models f(X2 > X2 calculated) 0.320 0.467 �1 ! ~'+ Table 11. yearlings, l. 000) . Survival estimates (program BROWNIE) of male sage grouse banded as North Park, Colorado, 1973-87 (upper confidence limit bounded at Year Estimate 1973 0.890 0.322 0.259 - 1974 1.201 0.474 0.273 - 1.000 1975 0.568 0.178 0.219 - 0.917 1976 0.738 0.234 0.280 - 1.000 1977 0.447 0.128 0.195 - 0.699 1978 0.370 0.140 0.096 - 0.644 1979 0.413 0.202 0.016 - 0.809 1980 0.541 0.202 0.145 - 1981 0.521 0.189 0.151 - 0.891 1982 0.454 0.206 0.049 - 0.858 1983 0.490 0.181 0.134 - 0.845 1984 0.291 0.165 -0.032 - 0.613 1985 0.160 0.085 -0.008 - 0.327 1986 0.150 0.114 -0.074 - 0.375 Average 0.517 0.059 S.E. 95% C.l. 0.400 - 1.000 0.938 0.633 �Table 12. Survival estimates (program BROWNIE) of male sage grouse banded adults, North Park, Colorado, 1973-87 (upper confidence limits bounded at 1.000) . S.E. as 95% C.r. Year Estimate 1973 0.360 0.167 0.032 - 0.688 1974 0.645 0.242 0.171 - 1.000 1975 0.220 0.079 0.064 - 0.375 1976 0.448 0.148 0.158 - 0.737 1977 0.325 0.102 0.126 - 0.524 1978 0.558 0.155 0.254 - 0.863 1979 0.846 0.259 0.338 - 1.000 1980 0.284 0.098 0.093 - 0.475 1981 0.319 0.098 0.127 - 1982 0.430 0.144 0.149 - 0.712 1983 0.226 0.090 0.050 - 0.403 1984 0.395 0.171 0.061 - 0.729 1985 0.090 0.056 -0.020 - 0.199 1986 0.230 0.156 -0.075 - 0.535 Average 0.384 0.028 0.329 - 0.438 0.511 �16 Table 13. Statistical tests of models grouse, North Park, Colorado, 1973-87. Model Log-likelihood d.f. (program SURVIV) of female sage Number of parameters estimated Akaike Information Criterion Goodnessoffit 3 -138.02l 118 2 280.041 0.918 2 -127.832 104 16 287.663 0.977 H -127.272 103 17 288.543 0.978 f(X2 General submodel 2 Reduced submodel calculated d. f. 2 3 20.378 14 0.119 H 3 21. 498 15 0.122 H 2 1.120 1 0.290 X LITERATURE > X2 calculated) CITED Brownie, C., D. R. Anderson, K. P. Burnham, and D.S. Robson. 1985. Statistical inference from band recovery data - a handbook. Second ed. U. S. Dep. Inter., Fish and Wildl. Servo Resour. Publ. 156. 305pp. SAS Institute, Inc. 1985. SAS Procedures 6 ed. SAS Inst., Cary, N.C. 373pp. Guide for Personal Computers, Ver. White, G. C. 1983. Numerical estimation of survival rates from band-recovery and biotelemetry data. J. Wildl. Manage. 47:716-728. Prepared by: Approved by: ~~ Mari1et A. Z an Graduate Research Assistant Clait E. Braun Wildlife Research Leader �17 JOB PROGRESS REPORT State of: Colorado Project: 'W-152-R 'Work Plan: Job Title: _3_: Responses Period Covered: Author: Job Upland Bird Research __lTh_ of Sage Grouse to Vegetation 01 January through 31 December Fertilization 1989 Orrin B. Myers Personnel: C. E. Braun, S. Porter, K. Snyder, Colorado Division O. B. Myers, G. C. 'White, Colorado State University; Upham, U.S. Bureau of Land Management of Wildlife; C. Cesar, L. ABSTRACT The response of sagebrush (Artemisia tridentata) and sage grouse (Centrocercus urophasianus) to nitrogen fertilization was studied in North Park, Jackson County, Colorado. Sagebrush plants responded to application of 112 kg-N/ha in Fall 1985 with increased growth and increased levels of foliar crude protein. Foliar crude protein levels remained significantly elevated over controls in samples collected in Spring 1989. A second application of fertilizer in 1987 produced a less dramatic response by sagebrush. Sage grouse used fertilized study plots for feeding significantly more often than adjacent unfertilized plots, however the magnitude of the effect declined over time. When presented with fertilized and unfertilized ~. ~. wyomingensis (AT'W) and ~. ~. vaseyana (ATV) in paired choice experiments, captive-reared sage grouse consumed significantly more of the AT'W treatments than of the ATV treatments, but fertilization did not increase the palatability of ATV. Wild-caught sage grouse performed poorly on all treatments used in digestibility trials, but birds were better able to maintain body mass on AT'W treatments than on ATV tre.atments.· Imperfect knowledge. of grouse me t abo Ld c .rates, thermoregulatory regime, and: forage intake and digestibility confounded attempt.s to assign an importance to detoxification cos t s associated with intake of mono t e'rpenes . Clutch sizes were not related to distance to nearest fertilized plot. Nitrogen fertilization can be used to locally increase grouse use of particular sites for feeding. Mechanisms involved in grouse selecting such sites cannot be elaborated due to short-comings in sampling strategies of this and all other sagebrush-herbivore studies. ��RESPONSES OF SAGE GROUSE TO VEGETATION FERTILIZATION Orrin B. Myers P. N. OBJECTIVES The project is part of a two-phased study to on sage grouse winter distribution in mining ecology, and to 2) evaluate whether nitrogen grouse winter habitat, can be used as a tool available to sage grouse. The focus of this Phase 2. 1) collect baseline information areas and on grouse feeding fertilizer, when applied to sage to mitigate reduction in habitat portion of the project is on SEGMENT OBJECTIVES 1. Document chemical fertilizer, and growth response of sagebrush 2. Evaluate feeding preferences of sage grouse for fertilized unfertilized sagebrush subspecies, 3. Estimate digestibility subspecies, and 4. Monitor reproductive parameters of radio-marked sage grouse to learn if sage grouse fitness is affected by fertilizer treatment. of fertilized to nitrogen and unfertilized and sagebrush DESCRIPTION OF STUDY AREA The study area is in North Park, Jackson County, Colorado. The Park is an intermountain basin at an elevation of about 2,500 m. It is drained to the northwest by the North Platte River, which is fed by many smaller streams. Topography is flat to rolling with numerous ridges and benches. Climate is cold and dry with an average annual frost-free period of 46 days. Sagebrushdominated grasslands cover upland sites in the Park, and grasses and sedges occur in native and irrigated meadows that border drainages. Artemisia tridentata is the dominant sagebrush species and includes 2 subspecies, ~. I. wvomin~ensis (ATW) and~. I. vaseyana (ATV). Other species of sagebrush also occurring in North Park are ~. lon~iloba, ~. cana, and~. ar~illosa. METHODS In October-November 1985 ammonium nitrate fertilizer (33.51 N) was applied at a rate of 112 kg-N/ha to 330 ha of sagebrush rangeland. Thirty-three 20-ha blocks were randomly-selected with 11 blocks distributed in each Area. The northern and southern 10 ha of each block were randomly assigned as fertilized or control and treated accordingly. In October 1987 fertilizer was applied to an additional 6 l-ha plots. The 3 main study areas contain similar densities of sagebrush plants, but the proportions of ATV and ATW differ between areas. �Sagebrush foliage was collected each quarter from a stratified, random sample of the 33 experimental blocks. Four blocks from each of the main study areas were sampled, and 5 randomly-located plants of the 2 big sagebrush subspecies were clipped from the control and fertilized halves of each study block. Sage grouse use of study blocks was estimated by examining individual plants for evidence of feeding activity. The characteristic appearance of leaves that have been fed upon by grouse has been described (Remington and Braun 1985). Equal numbers of each subspecies were examined along pace transects through the control and fertilized portions of randomly selected study blocks. Sampling points were at random distances along transects. Sage grouse were trapped at nocturnal roosts to attach radio packages and to provide birds for captive experiments. Radio-marked birds were located periodically to assess any use of experimental blocks and to monitor reproductive success. Male and female grouse were counted on leks between about 0500 and 0730 from 01 April through the first 2 weeks of May. Ground searches were made for new or relocated leks. Feeding trials were conducted with captive sage grouse to estimate feeding preferences for and digestibility of Wyoming big sagebrush, Artemisia tridentata wyomin~ensis, (ATW) and mountain big sagebrush, a. ~. vaseyana, (ATV). Two levels of fertilization also were tested: no fertilization (ATW and ATV) and 112 kg-N(ha (FATW and FATV). The 6 possible 2-way combinations of the 4 sagebrush treatments were presented to birds in random order to evaluate feeding preference for the different treatments. Sagebrush foliage was removed from stems and given to birds in 400 ml beakers. For each trial similar amounts of 2 treatments were placed on the left or right side of each cage prior to the morning feeding period. Positions of each treatment in the cages were determined randomly and then switched in subsequent trials. Prior to the start of trials, birds were given all treatments to avoid predisposing birds to preferring anyone treatment. Birds were allowed to feed for 60 min after which the sagebrush and spillage was removed and weighed. Digestibility trials were conducted by presenting to birds a single treatment at a time and collecting all excreta. Wild-caught grouse were used to estimate digestibility coefficients. Treatments were presented as whole sterns because wild birds could not be conditioned to feed upon picked leaves. The experimental design was 2-4x4 latin squares with assignments randomized by row and column separately for each latin square. Sagebrush stems and foliage were added to cages at about sunrise. Sagebrush also was placed on top of cages in the morning and weighed at night to provide an estimate of water loss during the day. Minimum and maximum ambient temperatures were recorded each day. After the evening feeding period sagebrush was removed from the cages and weighed. Spilled sagebrush was collected, weighed, and discarded. Diurnal fecal droppings were collected and stored overnight in resealable plastic bags. The following morning fecal droppings were collected and added to those already collected. Cecal droppings were placed into separate plastic bags. All droppings were frozen for storage. Sagebrush sterns and samples. treatment foliage samples were prepared for analyses by separating leaves from pooling equal amounts of leaves from each plant into composite Composite samples for each subspecies collected on the control and halves of each study block were ground in liquid nitrogen in a �mortar and pestle. Composite foliage samples collected during feeding trlalS were treated in the same manner. Grouse fecal and cecal droppings collec:ed in the course of feeding trials were freeze-dried and then ground in a mor:ar and pestle. Dry matter content of foliage and grouse droppings was determined after drying overnight at 100 C. Samples were ashed overnight at 500 C to determine organic matter and ash content. Kjeldahl nitrogen and gross energy (Hor~itz 1980) content of samples was measured. Soil samples were collected during early June from study plots fertilized in Fall 1987. Soil chemistry analyses were performed at the Colorado State University Soil Testing Laboratory, Fort Collins. Data were analyzed as randomized block experiments with year and fertilizer treatments handled in a factorial arrangement. This arrangement ignores the correlation of measurements made on the same experimental units in different years. I developed a model to evaluate the relative importance of factors influencing sage grouse energetics. Important tasks in developing the model were developing estimates of sage grouse food intake, partitioning of intake energy, animal maintenance requirements, and reproductive requirements. Dry matter intake (DMI) of sage grouse was estimated from captive feeding trials (Myers unpubl. data) and allometric equations (Moss and Hanssen 1980). A base dry matter intake of 100g/day was used. Sagebrush energy content, fecal energy values (PFE) , methane production (0.5% of DE [Gasaway 1976]) and excretion of fecal metabolic energy plus urinary endogenous energy were estimated so that intake energy could be partitioned on a true metabolizable energy basis (Sibbald 1976, Robbins 1983). The specific dynamic action was assumed to be 12% of intake energy (Ricklefs 1974). Energy costs for maintenance-type activities was calculated as the sum of energy for basal metabolism (BMR) , energy for thermoregulation, and energy lost through detoxification of monoterpenes. Estimates of BMR were produced using allometric prediction equations of Zar (1968) and Andreev (1988) for BMR and standard metabolic rate (SMR). Three equations were used for prediction: an equation for non-passerine birds [ZAR 1: Y(kJ/day) - 78.5 x 4.184 x (maSSkg)O.7nJ' an equation for galliform birds [ZAR_2: Y(kJ/day) - 72.6 x 4.184 x (maSSkg)o.98], and a second equation specific for galliform birds [ANDREEV: Y(kJ/day) - 1.35 x (mass~)O.855]. Predictions were compared with SMR estimates for male sage grouse dur~ng breeding (Fig. 1). Equations from Zar (1968) agreed well with estimates produced by Vehrencamp et al. (1989), with the equation for non-passerine birds being the best predictor of male SMR. However, measurements were performed on birds captured from the wild that were held for a short period of time, so estimates of basal metabolism likely are biased high. Female BMR was calculated from ZAR_l using a mean body mass for adult females in spring (1745 g) (Beck and Braun 1980). Thermoregulatory costs were calculated assuming that female grouse have the same lower critical temperature and thermal conductance as male sage grouse. These assumptions ignore sage grouse sexual size dimorphism (Beck and Braun 1980), which should affect these parameters. During April-May, adult males weigh an average of 3190 g, yearling males weigh 2890 g, adult females weigh 1745 g, and yearling females weigh 1550 g. Lower critical temperature was set at 7 C and thermoregulatory costs below 7 C were estimated by Y - 141.3-20.3 (degrees C) (Fig. 2, adapted from Vehrencamp et al. 1989). �1400 I I r! Ii .ulORHV 1200 r- , ZAR 1 ! i i i ZAR 2 ; I :-! 1000 >- < ~ I VEHRElICAl!? , 0 I I I f- ! <, ...., -'"' 0: x:: en 3CC r --- I --- ~ I I 500 r --- _ BODY Fig. 1. Estimates predictive equations al. 1989). ........ __ ... .i.>: ...... 2500 1500 1000 . --~! 3000 3500 :-lASS (3") of grouse standard metabolic rates and doubly-labelled water (Vehrencamp by et 1300 1200 ~ t rico ..:~ >- 1:000 ...,..•.. 900 .>< 800 700 SMR ~ -----------------------------------------------------------~---- 600 ~----~----~------~'------'~----~I------~----~----~ -15 -25 -20 -10 -5 5 10 15 AnBI~NT T~HPERATURE CC) Fig. 2. Energy costs of thermoregulation for male sage grouse in spring (adapted from Vehrencamp et al. 1989). In northcentral Colorado, sage grouse feed preferentially upon one subspecies of sagebrush. Wyoming big sagebrush, ~. t. wyomingensis (ATW) , plants are preferred forage and contain about twice the monoterpene concentration as do plants of the under-used subspecies, a. ~. vaseyana, CATV - mountain big sagebrush) (Remington and Braun 1985). The absolute amounts are small, however with about 1.5 to 3% of leaf dry matter for ATW and ATV, respectively. I assumed that monoterpenes are 90% digestible (Foley et al. 1987), even though they may not be that highly digestible in grouse (Remington 1983) to provide the most powerful test of whether monoterpene detoxification competes with reproductive costs. I �Monoterpenes are relatively small molecule, and probably are detoxified bv Phase I and Phase II reactions that hydroxylate and conjugate the molecul~s (Sipes and Gandolfi 1986). Ornithine traditionally has been cited as the mos: common conjugate in birds, but Remington (In prep.) did not detect ornithine conjugates in droppings from blue grouse, Dendragapus obscurus, fed several monoterpenes. Instead, he found elevated glucuronic acid conjugates in droppings. Glucuronic acid conjugation of terpenes also was detected in brushtail possum, Trichosurus vulpecula (Dash 1988). Sage grouse were assumed to excrete all digested monoterpenes as glucuronic acid conjugates. Phase I and Phase II detoxification reactions are coupled along the microsomal membrane and should result in the net loss of one ATP in addition to the energetic equivalent of one mol of glucose for each conjugate formed. Glucose catabolism by glycolysis and the citric acid pathway is about 46% efficient at recovering the combustive energy in glucose (2870 kJ/mol) at ATP, with the balance lost as heat (Martin et al. 1985:137). Therefore, 2907 kJ/mol total energy or 1357 kJ/mol or 37 ATP are lost for each -onjugate produced and excreted. Loss of carbon skeletons may not be complete, however, as gut. microbes containing beta-glucuronidase are able to remove glucuronic acid from the conjugate. Once released, glucuronic acid may be absorbed and recycled by enterohepatic recirculation (Sipes and Gandolfi 1986). Energy cost to produce a clutch was estimated from the energy value for a typical galliform egg (1.64 kcal/g fresh x 4.184 kJ/kcal) and 30% inefficiency for energy deposition (Ricklefs 1974). Average egg mass times these multipliers was summed across the number of eggs in the clutch. Number of days to complete a clutch (NDAYS) was estimated using a typical laying sequence (Patterson 1952) and an assumption that the number of rapidly growing follicles is equal to mean clutch size (8) (Hannon et al. 1979). NDAYS was the number of daily time steps that NEp was summed over for comparison with energy required for completion of the clutch. The difference between total NEp and total energy for egg formation was the net energy available for activity. RESULTS Inadequate numbers of captive hens were available to conduct feeding preference trials in a 6 x 6 latin square, so 3 hens and 1 cock were used in randomized block design. In most cases relative consumption of sagebrush was strongly (f < 0.01) affected by treatments presented (Table 1, Fig. 3). In trials where an ATW or FATW treatment was paired with FATV or ATV treatments, the ATW-FATW treatments were preferred (f < 0.01, Table 1) indicating a subspecies effect on feeding preferences. On average, relative consumption of ATW-FATW treatments was 95.5% of total intake compared to 4.5% for ATV-FATV. The effect of fertilization on feeding preference was weaker than the effect of subspecies. The ATV and FATV treatments were consumed equally and FATW was favored over ATW only if a comparison error rate of alpha - 0.06 is acceptable. Over the 4 trials where fertilized treatments were compared with control treatments (Table 1, trial numbers 2, 3, 4, and 5) FATW-FATV treatments and ATW-ATV treatments comprised 52.7% and 47.3% of measured intakes, respectively. Consumption of ATV treatments relative to ATW was low (trial 1) and did not increase when FATV was paired with ATW (trial 4). Cage position did not significantly affect consumption of sagebrush treatments (E > 0.25). 0 �Table 1. Relative consumption (X intake during trials) of sagebrush during i-hour preference trials conducted in February-March 1989. Consumption of treatments was not affected by cage position (f > 0.25). Probability values should be considered significant at f < 0.0083 (experiment alpha - 0.05/6). f > I Treatment Trial 1 ATV ATIl 7.5 92.5 0.0001 2 ATV FATV 5l. 6 48.4 0.9 3 ATV FATIl 3.6 96.4 0.0001 4 ATIl FATV 96.5 3.5 0.0001 5 ATIl FATIl 37.5 62.5 0.06 6 FATV FATIl 3.6 96.4 0.0001 P < 0.01 P > 0.2 P < 0.01 P > 0 ATW AT\/ 1 FATW P < 0.01 P < 0.01 D FATV 3. Relative consumption of sagebrush treatments by captive sage grouse. Probability values are for the Ho: that consumption was equal. Fig. �- _' Intake of sagebrush treatments did not differ for the digestion trials CE > 0.5, Table 2), and sage grouse lost an average of about 30 g/day during their period of captivity. Birds lost an average of 31.3 g/day while on ATV-FArv treatments regardless of dry matter intake. The regression coefficient for g body mass change/day on dry matter intake of ATV-FATV was not different from 0 CE > 0.8, Fig. 4). When ATW-FATW treatments were considered, the linear regression of body mass change CY) on intake CX) was Y ~ -55.3 + 0.8X CE 0.0003, R2 ~ 0.5966). The equation predicts a daily mass change - 0 at 69,1 g-DM intake/day. Variability about the regression line undoubtedly was increased by variable gut fill, fluctuations in ambient temperature, and by different activity levels of birds. Moreover, differing acclimation to captivity probably influenced losses of body mass. Table 2. treatment Intake of dry matter Cg) by captive sage grouse during digestibility trials conducted in April-May 1989. ~ SE 35.4 32.6 35.9 46.4 7.4 7.4 8.3 7.8 Treatment ATV ATW FATV FATW single 3C ·20 ...J 0" 10 U'l CI'l ATV T~:::ATl::::~TTS * 0·........................ · ATV TRL.A.TliENTS * * -10 >Q 0 -20 ;z; 0* 0* * co i I I I * *° ................... *........................................... ':.: ........ '"" r-. -30 / H ::u i -*----------, ' j 0 <C :c * '...1 -40 lJ ;z; <C -50 U -60 ° * * ° >-....J -70 H <C Q * -80 0 20 40 DRY Fig. 4. treatments. Daily change MATTER in body mass 90 60 =NTAKE of (g) captive grouse fed sagebrush �26 Seasonal sagebrush foliage samples were collected. Grouse feeding activity in study blocks for all years was summarized (Fig. 5). In 1987 transects were conducted twice--once in February and again in April-May. Measured use of ATN plants increased between February (10% of FATW plants browsed) and April-May 1987 (33% of FATW plants browsed). Feeding activity on control plots was low throughout the study (Fig. 5) and was low on ATV-FATV plants relative to ArJFATW. In each year FATW plants received more browsing pressure than ATW plants (f < 0.05), but this effect diminished. The number of ATV and FATV plants found with evidence of grouse feeding activity was too small to establish annual trends. 41] F ATTN ~ 32. 5 I - 30 (', ~ ~ 1 ATW r""'A .:» T '--1' A ~~r , . l '/ CJl :s= 0 .--V ~ ~ ')D '-' ' (-v""\ 10 o 1987 1988 1989 YEAR Fig. 5. Sage grouse feeding activity on North Park study plots. �Estimates of soil chemistry parameters were similar on control and fertilized plots in 1987 before fertilizer was applied (Table 3). Levels of NO)-N on control plots were not different (f > 0.25) from fertilizer plots in 1987, bue increased significantly on fertilizer plots following fertilization (f < 0.05). Soil nitrogen decreased (f < 0.05) between 1988 and 1989, but a treatment effect was still evident in 1989 (f < 0.05) although N03-~ had approached background levels (Table 4). Soil nitrogen levels on control plots did not change significantly with respect to year. Other soil parameters apparently were not affected by fertilization (f > 0.05, Table 4). Estimated pH, OM, P, Zn, and Cu changed significantly (P < 0.05, Tables 3 and 4) between 1988 and 1989. Organic matter, Zn, and Cu increased in 1989 compared to 1988 and pH and P declined. Differences between years in soil chemistry could be due to phenological differences between years. Sampl~~g was timed to the calendar rather that to phenology. Also, differences between years could be artifacts of sampling or laboratory procedures. Fertilizer treatment increased sagebrush foliar crude protein levels over controls but not in all sampling periods (Fig. 6, Table 5). The fertilizer effect was greatest the first spring after treatment and was much reduced in subsequent springs when grouse might accrue fitness benefits due to enhanced levels of dietary protein. The probability that treatment plots had evidence of grouse feeding was related to the foliar crude protein levels of plants collected on the plot (Fig. 7). Few ATV plants showed any evidence of grouse feeding, so a second analysis was performed on ATW plants only. The relationship between foliar crude protein and the probability approached linearity. Each foliage sample analyzed, however, represented a mean of 5 25 --~ A,TV 20 r ~ FATV A,TW FATW z 15 I- 10 I- 5 I- W f- o IT Q_ w o ~ rr u . ii! o 86/05 871 D5 86/11 86/08 871 G2 88/04 88/01 88/10 88/06 89/04 DATE Fig. 6. Foliar crude protein levels of sagebrush plants on North study plots. Plots were fertilized in Fall 1985 with 112 kg-Nfha. Park �.28 Table 3. Soil chemistry measured on 1-ha study plots in North Park, Jackson County, Colorado. Digits are not significant beyond 1 decimal place. Year Treatment 1987 Control Variable N pH Condo OM N03 -N P 6 6 6 6 6 6 6 6 6 6 6.8333333 0.1833333 3.1000000 0.5833333 4.2333333 231.1666667 0.8166667 23.8833333 2.9500000 2.1500000 0.1626175 0.0401386 0.3559026 0.0833333 0.4302454 33.0982544 0.0872417 5.5341616 0.2140872 0.1607275 6 6 6 6 6 6 6 6 6 6 6.7333333 0.1500000 2.8666667 0.6666667 3.6666667 205.1666667 0.7666667 24.0333333 2.9333333 2.1333333 0.0802773 0.0223607 0.3190263 0.1054093 0.6221825 28.4375534 0.0557773 4.2359310 0.2076322 0.1646545 6 6 6 6 6 6 6 6 6 6 7.4833333 0.2166667 1.8000000 0.7500000 2.6500000 193.8333333 0.3500000 14.9166667 2.0000000 1.8500000 0.0945751 0.0166667 0.2463060 0.2500000 0.4958158 22.0838050 0.0341565 2.5536140 0.0683130 0.1746425 6 6 6 6 6 6 6 6 6 6 7.2333333 0.2833333 1.8500000 7.0000000 2.8500000 203.1666667 0.4833333 19.6500000 2.4333333 1.7333333 0.2139574 0.0307318 0.3008322 2.0330601 0.6946222 23.6056726 0.0703167 5.4224687 0.2485514 0.1475730 K Zn Fe Mn Cu Fertilized pH Condo OM N03-N p K Zn Fe Mn Cu 1988 Control pH Condo OM N03-N p K Zn Fe Mn Cu Fertilized pH Condo OM N03-N P K Zn Fe Mn Cu Mean SE �Table 3. (continued) . Year Treatment 1989 Control Variable pH Condo OM NO)-N P K Zn Fe Mn Cu Fertilized pH Condo OM NO)-N p K Zn Fe Mn Cu N Mean SE 6 6 6 6 6 6 6 6 6 6 7.1000000 0.2166667 2.566666, 1.0000000 1.9833333 217.5000000 0.5500000 22.1166667 2.1833333 8.5500000 0.5300419 36.3737543 0.0562731 5.5205928 0.1077549 0.6222272 6 6 6 6 6 6 6 6 6 6 7.0166667 0.1833333 2.3000000 1.6666667 2.2666667 207.6666667 0.5333333 21.0000000 2.1333333 8.6833333 0.1301708 0.0307318 0.2875181 0.2108185 0.4558265 28.2284333 0.0421637 4.1108799 0.1819646 0.4150636 0.1238278 0.0600925 0.3783003 0 �30 Table 4. Analysis of soil chemistry measurements on I-ha study plots in North Park, Jackson County, Colorado. YEAR tests for changes in soil chemistry between 1988 and 1989. TREATMENT tests for changes in soil chemistry due to fertilization with 112 kg-Nfha in Fall 1987. pH Source BLOCK YEAR TREATMENT YEAR*TREATMENT DF Type III SS Mean Square 5 1 1 1 0.60833333 0.54000000 0.16666667 0.04166667 0.12166667 0.54000000 0.16666667 0.04166667 OF Type III SS Mean Square 5 1 1 1 0.07500000 0.01500000 0.00166667 0.01500000 0.01500000 0.01500000 0.00166667 0.01500000 OF Type III SS Mean Square 5 1 1 1 9.11708333 2.22041667 0.07041667 0.15041667 1.82341667 2.22041667 0.07041667 0.15041667 DF Type III SS Mean Square 5 1 1 1 32.55208333 38.76041667 71.76041667 46.76041667 6.51041667 38.76041667 71.76041667 46.76041667 OF Type III SS Mean Square 5 1 1 1 32.94375000 2.34375000 0.35041667 0.01041667 6.58875000 2.34375000 0.35041667 0.01041667 f .r. 0.91 4.05 l.25 0.31 0.4994 0.0626 0.2813 0.5846 I f > I 2.29 2.29 0.25 2.29 0.0983 0.1511 0.6214 0.1511 I f > I > I Conductivity (mmhos/cm) Source BLOCK YEAR TREATMENT YEAR*TREATMENT Organic matter (1) Source BLOCK YEAR TREATMENT YEAR*TREATMENT NOrN 12.48 15.20 0.48 l.03 0.0001 0.0014 0.4981 0.3263 (ppm) Source BLOCK YEAR TREATMENT YEAR*TREATMENT I l.03 6.14 11.37 7.41 f > I 0.4344 0.0256 0.0042 0.0157 P (ppm) Source BLOCK YEAR TREATMENT YEAR*TREATMENT I 27.70 9.85 1.47 0.04 f > I 0.0001 0.0068 0.2436 0.8371 �Table 4. (continued) . K (ppm) Source BLOCK YEAR TREATMENT YEAR*TREATMENT OF Type III SS Mean Square 5 1 1 1 80113.20833 1190.04167 0.37500 55l.04167 16022.64167 1190.04167 0.37500 55l.04167 OF Type III SS Mean Square 5 1 1 1 0.12708333 0.09375000 0.02041667 0.03375000 0.02541667 0.09375000 0.02041667 0.03375000 OF Type III SS Mean Square 5 1 1 1 2037.002083 109.653750 19.620417 5l. 333750 407.400417 109.653750 19.620417 51. 333750 OF Type III SS Mean Square 5 1 1 1 2.01875000 0.02041667 0.22041667 0.35041667 0.40375000 0.02041667 0.22041667 0.35041667 OF Type III SS 5 1 1 1 12.0020833 279.4837500 0.0004167 0.0937500 .E 16.20 l.20 0.00 0.56 f > .E 0.0001 0.2899 0.9847 0.4669 Zn (ppm) Source BLOCK YEAR TREATMENT YEAR*TREATMENT Fe .E f > .E l.86 6.87 l. 50 2.47 0.1609 0.0192 0.2400 0.1366 .E z (ppm) Source BLOCK YEAR TREATMENT YEAR*TREATMENT 13.23 3.56 0.64 1.67 > .E 0.0001 0.0787 0.4372 0.2163 Mn (ppm) Source BLOCK YEAR TREATMENT YEAR*TREATMENT .E f > .E 4.60 0.23 2.51 3.99 0.0096 0.6365 0.1338 0.0641 Mean Square .E f > .E 2.4004167 279.4837500 0.0004167 0.0937500 5.67 660.24 0.00 0.22 0.0039 0.0001 0.9754 0.6447 Cu (ppm) Source BLOCK YEAR TREATMENT YEAR*TREATMENT �.32 Table 5. sagebrush Analysis of variance summary of foliar crude protein plants fertilized in Fall 1985. levels of Effect f > .E May 1986 Block Subspecies Fertilizer S x F interaction 0.1254 0.0001 0.0001 0.0087 August Block Subspecies Fertilizer S x F interaction 0.4531 0.0001 0.0001 0.1673 Sample date 1986 November 1986 Block Subspecies Fertilizer S x F interaction 0.0071 0.0001 0.0383 0.1163 February 1987 Block Subspecies Fertilizer S x F interaction O. 0012 0.0001 0.0001 0.9385 Block Subspecies Fertilizer S x F interaction 0.8278 0.0001 0.2082 0.3021 Block Subspecies Fertilizer S x F interaction 0.1479 0.0001 0.1530 0.8106 April 1988 Block Subspecies Fertilizer S x F interaction 0.0306 0.0001 0.0015 0.8584 June 1988 Block Subspecies Fertilizer S x F interaction 0.2720 0.0011 0.4610 0.0845 October Block Subspecies Fertilizer S x F interaction 0.0033 0.0001 0.9139 0.1349 May 1987 January 1988 1988 �Table 5. Sample April (continued). Effect f > .E Block Subspecies Fertilizer S x F interaction 0.0042 0.0001 0.0400 date 1989 plants and sage grouse the pooled herbivores 0.3183 provides no information on the chemistry of individual plants that select or avoid. All studies of herbivory on sagebrush have used plant sample approach and, thus, it cannot be established whether are selecting/avoiding particular sites or plants within sites. ATV ATY Only o B CJ"I C . ..-4 -g 0 6 :u ~ QJ 'o~ z: o 0.4 o 2 o 6 8 10 foliar 12 Crude 14 Protein 16 18 20 (%Dtl) Fig. 7. Probability that plants on North Park study plots had been fed upon by sage grouse in relation to foliar crude protein levels. Lek sites and fertilized plots were mapped to describe spatial relations between plots and leks. Six leks were located in proximity to study blocks: Buteo, Hawk, Denmark, Turkey, Raven, and Perdiz. Overall, 85% of fertilized plots lie partially or wholly within 3-km radii around leks (Fig. 8). Important grouse nesting habitat generally is assumed to exist within 3 km of leks (Braun et al. 1977). Eight of the 11 plots in Area A (NW cluster of �plots) were within 3 km of a 11 Area C plots (SE cluster) (Fig. 8). Thus, female sage opportunity to choose a nest other factors being equal. lek, all Area B plots (central cluster), and 9 of were at least partially within the 3-km buffer grouse attending these leks should have had ample site in close proximity to fertilized plots, all j::<:"': ..... *::::. .:l ., 5) (, ~... , ~~ i .. ! , Jt ,I :::: w- -~- ,/ 4518~ 4S16~ /\ E } V>~ 451L1 <t ::J. u I --= h85?>~/. < .: 45 12 :.::......... (/ . / _.. \" f- a: o 4510 :::2 4508 z f- ~ ...'. '.8 .••. ·.~.:::.~ ••.• ••.••.••.••.• ~ •••..•.••••• ~ :.:: ~ ..........•......... '~":: :J - 4506 .......... ......... ............... .. ........... • 4504 -:-:.:::::-:«.: ............ PLOTS * .....,... . -:-:-:-:.»»»> ~:'::~::':'.'. /.. ':-: :<':-.':':-:-:<-:':' ••••••••. «<.:-:-:-:.»» -:-::::::::::-:::::lIt:: LEKS 4502~~~~~~--~~~~~~~~ ]9] ]97 UTtv1 EA.ST 401 405 C kmJ Fig. 8. Locations of study plots with Filled circles are 3-km radii from leks. respect to leks. I located 33 nests, of which 14 were within 1.S km of a fertilized plot (Fig. 9). During egg-laying, movements of hens to feeding/loafing areas have averaged 1.S km and then decreased to 0.1 km during incubation (Petersen 1980). Additional marked hens attempted to nest in NE North Park, but their nests were not found due to early nesting failure. I attempted to locate nests after incubation was underway to reduce incidence of observer-caused �3) abandonment. Only 1 nest by a marked hen was in a fertilized plot. Although radio-marked hens had opportunity to nest in fertilized plots (about 85% of plots were within 3 km of leks), most did not. * 45::J4 , ~ _ f"JESTS PLOTS 4520 4516 I) I f- \ nO z . [ I 4512 . .. .. . 2 f- :=) 4508 cr{_ --.- 4504 2 km 4500 390 394 UT~1 Fig. 9. Locations 398 402 406 EAST of sage grouse nests with respect to North Park study plots. There was no linear relationship between clutch size and distance to fertilized plots (f - 0.09, R2 - 0.1281). When nests within 3 km of fertilizer plots were considered, no relationship was found between clutch size and distance (f> 0.5, R2 - 0.0519). �36 The 3 years of estimated harvest prior to fertilization (NEHARV LSM£&~ - 30 birds) was lower than for the 3 years of post-fertilization data (NEHARV LSMEAN - 42 birds) (f < 0.05). However, if pre-fertilization data spans 6 years there is no difference in NEHARV estimates (f > 0.7). An examination of the residuals for the multiple regression of NEHARV on OHARV and NEHUNT (f < 0.01, R2 ~ 0.7119) presented by year reveals an apparent correlation of errors with respect to year. County-wide production indices were available for inclusion in the model, but they did not improve the fit (f > 0.05). Correlated errors could indicate fluctuations in habitat conditions and survival that influence the number of birds available for harvest in the fall. Changes in hunter access also could have influenced harvest. Additional variables will be examined to evaluate reasons for correlated residuals. Eighteen comparisons were made of the differences between control and treatment leks during the years before and after fertilization (Table 6). If the experiment error rate is controlled to alpha - 0.05 by applying the Bonferrroni inequality (Sokal and Rohlf 1986), none of the comparisons was significant (f < 0.0028 required for significance). If a comparison error rate of alpha - 0.05 is acceptable, then counts of males at Coalmont lek increased over those at Raven lek after fertilization relative to before fertilization and the difference between counts at Ridge Road lek and Tur:. lek became significantly greater after fertilization. Other treatment-control lek pairs did not show significant changes from pre-fertilization periods. Table 6. Differences between treatment before and after fertilizer application. and control lek counts for periods n Treatment lek Control lek (Before/after) f > III Buteo Fish Hatchery Thrasher 5/3 5/3 0.3006 0.2313 Denmark Boettcher Delaney Butte Fish Hatchery Migan 9/3 8/3 9/3 5/2 0.8934 0.1425 0.2161 0.1483 Perdiz Alkali Lake Aspen Deer Creek Lost Creek 8/3 8/3 8/3 7/3 0.0908 0.2960 0.2753 0.2686 Raven Arapaho Cheyenne Coalmont Delaney Butte Fish Hatchery Lost Creek Migan 9/3 8/3 9/3 8/3 9/3 9/3 6/2 0.0307 0.0473 0.0039 0.4449 0.5068 0.0588 0.0124 Turkey Ridge Road 5/3 0.0210 �,- ) I Adequate energy was available for maintenance, reproduction, and activity under the initial conditions of the model (DMI - 100 g/day, Monoterpenes 1.5% of leaf DM, and bird at thermoneutrality). Daily N~ after 7 days was adequate to form a clutch of 9 eggs if activity was held to zero. The daily energy available for activity averaged about 260 kJ, compared to a BMR requirement of 490 kJ/day. Detoxification costs were small (29 kJ/day) compared to activity costs, which can be considered to be somewhat flexible. When monoterpene concentrations were raised to the level found in the unpalatable subspecies (3.0% of leaf DM), detoxification costs increased to 58 kJ/day, or about 5% of ME intake. I reasoned that thermoregulatory costs likely were important contributors to energetic costs incurred by sage grouse. Birds may also be able to control demands for thermogenesis by selecting appropriate roost sites, e.g., under a sagebrush plant and out of the wind. I added thermoregulatory costs to my grouse energy budget by randomly drawing temperatures from a uniform distribution of temperatures over a range I observed in Jackson County during April-May 1989. Temperatures are daily medians and are assumed to approximate average daily conditions. During a typical 19-day period to form and lay 9 eggs, an average adult female grouse used 94 kJ/day for thermoregulation, which was 1.6 times the detoxification costs associated with ATV. Daily thermoregulatory costs ranged between 0 and 261 kJ/day (0-21% of ME). When I also allowed terpene levels to vary between 1 and 4.3% DM, the amount of energy left after egg production averaged 230 kJ/day and detoxification costs remained small relative to the simulated cost of thermoregulation (Fig. 10). 300 f DETOXIFICATION . 1\ 1\ I \ I \ I , j \ I \ 250 ~ I I I I • II II I ~ I' I I , , \ \ \ \ I I I 200 : I I \ I/ I I ~ II 1\ A \ \ \ \ : II I I , \ , \ ,\ : I I I I r I \, I I I I f J I \ , I I r r I I \ I I I I I \ ~ I ·'~·--·-·"---"--'·"·'···'·'-··'·"-----··········T·························T··· I I : I I I I I I : ~ I I I I I I I I \ I I I I I I I i ~ I J \ \ \ I \ I I :\ \ "~ I 'I ,\ \ I I I I '" II I I I I I I I , I I J I 150 100 THER.tfOREGULATION I \ I \ I I I I I L I I I I I I , I I I \ i 1\ 1\ I I \ I I I I I I I I I It It 1\ , \ I \ I I I I I \ I I I I I I I \ \I I :MEAN : ·····-t···········.,··············"1'·························T·· I I " I I L , , '" I I 50 I I I I I L I I I f I I I I I , I I \I .... ··,·············· \ I I I \ I , , I , I I J I ,, o 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 DAY Fig. 10. Relative energy costs due to detoxification of monoterpenes and thermoregulation during a typical period of egg production and laying (clutch size - 9). �38 Energy costs for egg production are not uniform through the laying interval (Fig. 11). During the middle of the period when eggs are deposited, total daily costs can reach 270 kJ/day, leaving little energy left for activity if thermoregulatory costs are high. Under such circumstances grouse likely exploit endogenous lipid reserves (about 3-6% of live body mass) to meet energy needs. Interestingly, by extending the period of egg formation and laying from 1 egg/day to 1 egg/l.3 day the maximum daily cost is reduced by 50 kJ, while the total cost remains the same. This cost is about equal to detoxification costs. 70 Clutch Size: 9 LaYlnq Rat. = eqq/l 60 3 day 50 20 10 o 1 2 3 4 5 6 7 B 9 10 11 12 13 14 15 16 17 18 19 20 DAY Fig. 11. Daily energy costs to female sage grouse while forming a clutch of 9 eggs when typical laying sequence involving skipped days is followed. I was interested in how my model inputs affected estimates of detoxification costs. Sensitivity analyses1 were performed on model outcomes produced by factorial sampling at 3 levels for the effects of clutch size (CLUTCH), temperature (TEMP), concentration of monoterpenes in sagebrush foliage (PTERP), female body mass (BMASS), dry matter intake rates (DMI), forage digestibility (l-PFE), digestibility of monoterpenes (PTERP), and the method used to calculate BMR requirements (METHOD) (Table 7). 1 Several small changes to the model inputs were made after I performed the sensitivity analyses. I do not believe these modifications changed the outcome of the analyses, as sources of uncertainty were rather obvious a priori. �39 Table 7. Parameters and their values used in factorial sensitivity analysis. Parameter Levels Values CLUTCH TEMP PTERP BMASS DMI PFE METHOD 3 3 3 3 3 3 3 7 8 9 0 7 -14 o 0.03 0.015 1570 1745 1920 108 120 132 0.361 0.425 0.489 ANDREEV ZAR 1 ZAR 2 Average daily energy available for activity was most strongly influenced by temperature, BMR estimation method, diet digestibility, and dry matter intake rates (Table 8). TEMP and METHOD are components of maintenance-type costs, and DMI and PFE are strong modifiers of the amount of energy available for metabolism. BMASS exerted strong effects due to its entry into the equations that estimated BMR requirements. An additional sensitivity analysis was performed to examine the effects of CLUTCH, PTERP, AND DTERP on energy for activity (Table 9). Based on relative f values, foliar mono terpene concentrations were more important than their digestibility or clutch. Table 8. Factorial sensitivity analysis of parameters in sage grouse bioenergetics model. Dependent variable is daily energy for activity averaged over laying period. Source Model CLUTCH TEMP PTERP BMASS DMI PFE METHOD DTERP DF Sum of squares Mean square f value 16 514600279.1 32162517.4 99999.99 2 2 2 189259.7 185233522.9 492459.0 8017645.3 58383244.5 118919741. 0 143241291.8 123114.7 94629.9 92616761.5 246229.5 4008822.7 29191622.3 59459870.5 71620645.9 61557.4 315.25 99999.99 820.29 13354.93 97248.51 99999.99 99999.99 205.07 300.2 2 2 2 2 2 Error 6544 1964348.6 Corrected Total 6560 516564627.7 �40 Table 9. Factorial sensitivity analysis of parameters in sage grouse bioenergetics model. Dependent variable is daily energy for activity averaged over laying period. Sum of squares Mean square I value 6 3124.525965 520.754328 30.83 2 2 2 591.300834 2026.580105 506.645026 295.650417 1013.290052 253.322513 17.50 59.99 15.00 Error 20 337.797657 16.889883 Corrected Total 26 3462.323622 OF Source Model CLUTCH PTERP DTERP Flexibility in grouse behavior may be the dominant means that grouse use to make adjustments for nutritional constraints (King and Murphy 1985). For example, male sage grouse displaying at leks show a wide range of daily energy expenditures that were correlated with number of reproductive displays (struts) (Fig. 12). The few males that were successful breeders « 51 of population) had daily energy expenditures that were double that of males that did not display (Vehrencamp et al. 1989). Not surprisingly after the effect of display behaviors was statistically controlled, male sage grouse that 2.400 2.200 2.000 >< -< 1.BOO 0 <, I--) -'< 1.600 1.400 1.200 1.000 a 200 400 600 BOO 1.000 STRUTS/DAY F1g. 12. Daily energy expenditure of male sage grouse in spring in relation to strutting intensity (from Vehrencamp et al. 1989). �,, ~l foraged the farthest from display sites during the day also had daily energy expenditures that were greater than those that traveled less. Yith such a broad expanse in the amount of energy expended toward activity it seems unlikely that 60 kJjday cannot be made available for detoxification of monoterpenes. Compounds other than monoterpenes may add to the energy drain due to detoxification, however, and other plant defense compounds could substantially influence grouse energetics by acting quantitatively to reduce forage digestibility. Sagebrush secondary chemistry also could have qualitative effects on grouse. The parameters that influenced sage grouse energy balance estimates the most were components of BMR, thermoregulation, and food intake and processing. Reliable estimates for basal metabolism and forage digestibility should not pose great problems using captive grouse, but parameters that include a behavioral component, like thermoregulation, will be more difficult to obtain. LITERATURE CITED Andreev, A. V. 1988. Ecological energetics of Palaearctic Tetraonidae in relation to chemical composition and digestibility of their winter diets. Can. J. Zool. 66:1382-1388. Beck, T. D. I., and C. E. Braun. Condor 80:241-243. 1980. Weights of Colorado sage grouse. Braun, C. E., T. Britt, and R. O. Wallestad. 1977. Guidelines for maintenance of sage grouse habitats. Wildl. Soc, Bull. 5:99-106. Dash, J. A. 1988. Effect of dietary terpenes on glucuronic acid excretion and ascorbic acid turnover in the brushtail possum (Irichosurus vulpecula). Compo Biochem. Physiol. 89B:22l-226. Foley, Y. J., E. V. Lassak, and J. Brophy. 1987. Digestion and absorption of Eucalyptus essential oils in greater glider (Petauroidel yolans) and brushtail possum (Irichosurus vulpecula). J. Che•. &col. 13:2115-2130. Gasaway, Y. C. 1976. Methane production in rock ptaraigan (Li&opus ~). Comp Bioche •. Physiol. 54A:lS3-1S5. Hannon, S. J. B. R. Simard, and F. C. Zwickel. 1979. gonadal cycles of adult and yearling blue grouse. 1289. . t Differences in the Can. J. Zool. 57:1283- Horwitz, Y., ed. 1980. Official methods of analysis of the Association of Official Analytical Chemists. Assoc. Off. Anal. Che•. , Washington, D. C. 1018pp. King, J. R., and M. E. Murphy. 1985. Periods of nutritional stress in the annual cycles of endotherms: fact or fiction? Am. Zool. 25:955-964. Martin, D. Y., P. A. Mayes, V. Y. Rodwell, and D. K. Granner. 1985. Harper's review of biochemistry. Lange Medical Publ., Los Altos, Calif. 718pp. �Moss, R., and I. Hanssen. 50B:555-567. Patterson, R. L. 1952. Colo. 34lpp. 1980. Grouse nutrition. The sage grouse Nutr. Abstr. in wyoming. Sage Books, Rev. Denver, Petersen, B. E. 1980. Breeding and nesting ecology of female sage grouse in North Park, Colorado. M.S. Thesis, Colorado State Univ., Fort Collins. 86pp. Remington, T. E. 1983. Food selection, nutrition, and energy reserves of sage grouse during winter, North Park, Colorado. M.S. Thesis, Colorado State Univ., For,- Collins. 89pp. In prep. grouse. Costs of detoxification _____ , and C. E. Braun. 1985. Park, Colorado. J. wildl. of secondary compounds Sage grouse food selection Manage. 49:1055-1061. Ricklefs, R. E. 1974. Energetics Ornithol. Club 15:152-297. Robbins, C. T. 1983. wildlife York, N. Y. 342pp. of reproduction Sibbald, I. R. 1976. A bioassay Poultry Sci. 55:303-308. in winter, in birds. feeding and nutrition. for true metabolizable to blue North Publ. Nuttall Academic energy Press, New in feedstuffs. Sipes, I. G., and A. J. Gandolfi. 1986. Biotransformation of toxicants. Pages 64-98 in C. D. Klaassen, M. O. Amdur, and J. Dou11, eds. Casarett and Doull's toxicology. Macmillan Publ. Co., New York, N.Y. Sokal, R. R., and F. J. Rohlf. York, N.Y. 859pp. 1986. Biometry, 2nd ed. W. H. Freeman, New Vehrencamp, S. L., J. w. Bradbury, and R. M. Gibson. 1989. The energetic cost of display in male sage grouse. Anim. Behav. 38:885-896. Zar, J. G. Condor Prepared Approved 1968. Standard 70:278. metabolism comparisons &-+-_~ _ {f)_7:B __ by __ Orrin B. Myers Graduate Research Assistant by Clait E. Braun Wildlife Research Leader among orders of birds. �JOB PROGRESS REPORT Colorado State of: Project: __~W~-Al~5~2~-R~ Work Plan: 3__ : Job Job Title: Response Period Covered: Author: _ Upland Bird Research 17 of Selected 01 January through Avifauna to Fire in the Big Sagebrush 31 December Type 1989 Lee A. Benson Personnel: C. E. Braun, T. D. Abell, C. E. Spraker, C. E. Poley, Colorado Division of Wildlife; L. A. Benson, Colorado State University ABSTRACT The response of sage grouse (Centrocercus urophasianus) and passerine birds to fire was studied in Jackson and Moffat counties, Colorado. Sage grouse numbers and habitat use were monitored following a fall prescribed burn in Jackson County, Colorado. Sage grouse were also monitored at 2 wildfire sites, one in Jackson County and one in Moffat County. Lek counts were conducted during the breeding season. Radio-marked sage grouse were located during spring and summer. Few locations of radio-marked sage grouse occurred within burned areas during the breeding season. Movements to summering areas ranged from 3.4 to 25.3 km in North Park and averaged 1.6 km in Moffat County. Diversity and relative abundance of passerines were determined for the prescribed burn site and an adjacent unburned area in 1988-89. Passerines were also sampled at the Jackson County wildfire site (burned 1987). The prescribed fire site burned in a mosaic pattern and resulted in a 50-60% reduction in big sagebrush (Artemisia tridentata) within a 38-ha area. Both wildfires consumed nearly all sagebrush habitat. During spring 1987, 75% of 28 locations of radio-marked male sage grouse were within the proposed prescribed burn plot. Use of the burned plot by male sage grouse in 1988-89 was minimal (9 of 130 relocations). Peak male sage grouse counts decreased 43% at the lek closest to the burn from 1987 to 1989. Passerine responses differed greatly at the 2 burn sites in Jackson County. At the wildfire site, all passerines were eliminated except for horned larks (Erernophila alpestris). Species richness did not vary along burned and unburned transects at the prescribed burn site. Relative abundance at the prescribed burn site varied slightly between burned and unburned areas. ��RESPONSE OF SELECTED AVIFAUNA TO FIRE IN THE BIG SAGEBRUSH TYPE Lee A. Benson INTRODUCTION Sagebrush (Artemisia ~.)-dominated rangeland occupies major portions of the western United States. Reports of total area covered by sagebrush vary from 35 (Schroeder and Sturges 1975) to 60 million ha (Beetle 1960). More than 10% of all sagebrush lands have been altered by man (Braun et al. 1976). Among the methods used, fire is becoming increasingly more attractive as a management tool for reducing sagebrush (Frandsen 1985). This study was initiated as additional information is needed on the impacts of fire on wildlife so that any impacts can be more fully considered in management of the sagebrush type. The major uses of sagebrush ranges are two-fold. Cattle grazing, mainly during the summer months, is by far the predominant use of sagebrush regions. Recreation is also a factor in management of these areas. Hunting is the primary recreational activity occurring on rangelands in the western United States. Sage grouse dependence on sagebrush regions is well known. The original range of sage grouse parallels that of big sagebrush (~. tridentata), although the current range is reduced over that of previous decades (Johnsgard 1983). Settlement of the western United States appears to have resulted in a reduction in the range of sage grouse. Attempts to reduce sagebrush have generally not been successful in its eradication but have caused declines in sagebrush dependent wildlife. Sage grouse dependence or sagebrush is evident from life history studies of this species ...Food habits studies by Patterson (1952) show a high proportion of sagebrush in the diet of sage grouse. Winter food is restricted to sagebrush alone. During late spring and early summer months, sage grouse include other food items in their diet. Few studies have examined the effect of burning on sage grouse. Gates (1983) reported greater use of burned areas one year following a prescribed burn. Klebenow (1972) suggested that small irregularly shaped burns would benefit sage grouse in Nevada. Braun et al. (1976) recommended that sagebrush treatments should be small in size and done on productive sites. Connelly et al. (1971) located 3 leks on disturbed sites in Idaho. Several studies have assessed the impact of other forms of habitat manipulation on sage grouse. The general conclusion is that removal of sagebrush decreases sage grouse populations. Martin (1970) observed fewer grouse on chemically treated areas. Wallestad (1975) reported declines in sage grouse populations following sagebrush control in Montana. Ploughing of small areas of sagebrush resulted in declines of sage grouse in south-central Montana (Swenson et al. 1987). Other species of interest are Brewer's sparrow (Spizella breweri), sage sparrow (Amphispiza belli), and sage thrashers (Oreoscoptes montanus); these are considered to be sagebrush obligates (Braun et al. 1976). Also of �46 interest are green-tailed towhees (Chlorura chlorura), vesper sparrows, (Pooecetes gramineus) and horned larks. Braun et al. (1976) consider greentailed towhees and vesper sparrows to be near obligates of sagebrush habitat. P. N. OBJECTIVES 1. Review 2. Capture 6-10 male sage grouse per lek and equip with poncho-mounted tail-clip transmitters. 3. Locate and flush radio-marked 4. Obtain 5. Monitor 6. Establish 7. Measure vegetation structure and composition areas and at sage grouse use sites. literature pertaining lek counts on avian species. birds at spring feeding/loafing or sites. (minimum of 3) from study area leks. post-breeding transects to the impacts of burning movements of radio-marked and conduct breeding sage grouse. bird surveys at study areas. on treated and untreated STUDY AREAS Field research for this project was conducted in 2 northern Colorado counties. Three study sites were located in Jackson County in north-central Colorado. An additional site was located in Moffat County in northwest Colorado. 0 0 0 Jackson County lies between 106 42' and 105 50' west longitude and 40 20' and 41 north latitude. North Park comprises a large proportion of Jackson county. North Park lies between the Never Summer and Medicine Bow ranges on the east and .the Park Range on the western edge of the park. The southern border is comprised of the Rabbit Ears Range. Independence and Sentinel mountains mark the northern boundary. 0 Three sage grouse leks served as the approximate centers for the Jackson County study sites during the April-May interval. Deer Creek Lek was in the southeastern corner of North Park in the NW quarter of Section 31, Township 7 North, Range 78 West. Perdiz Lek was 14 km southeast of Walden in the NE quarter, Section 10, Township 8 North, Range 78 West. Fish Hatchery Lek was 10 km southwest of Walden in the southwest quarter of Section 9, Township 8 North, Range 80 West. Topography varied greatly between sites. The Deer Creek area was large, relatively flat expanses of two basic types. Bench top areas of 2590-2615 m in elevation form the area of the lek site. These benchtops extend north of the Deer Creek Lek 1.5 km with major areas to the south. Lower lying flat areas occurred directly west of the lek and off the north end of the bench on which the Deer Creek Lek is located (elevation 2548-2566 m). Areas of 20-40 lie between the benchtops and lowland areas at Deer Creek. 0 �47 The topography at the Fish Hatchery Lek was a series of small west to east ridge tops. Small drainages lie between these ridges. Also present were large expanses of low lying, alkali flats. This topography occurred east and northeast of the lek and forms the western edge of Case Flats. Elevations ranged from 2487 to 2511 m. The Perdiz Lek was in a depression with small scattered ridges sloping southwest to northeast towards Bolton Draw. To the west and north of the Perdiz Lek about 2 km were large areas with little topographic change. Elevations ranged from 2515 m near the lek to 2579 m in the large flat areas. The Moffat County site was 9 km west of Maybell. The lek was in the southwest quarter of Section 33, Township 7 North, Range 96 West. Elevations ranged from 1844 to 1963 m. The area was a series of large ridges sloping south to north. Large to moderate sized drainages separated ridges. METHODS Sage Grouse Capture and Radiomarking.--Sage grouse were spotlight and a long-handled net on or near were banded with serially numbered aluminum color coded by year. Age, sex, weight, and each bird captured. captured at night using a leks (Giesen et al. 1982). Birds leg bands and plastic bandettes primary molt were recorded for Twenty-nine sage grouse were fitted with either poncho (Amstrup 1980) or tailclip (Bray and Corner 1972) radio transmitters obtained from Wildlife Materials (Carbondale, IL), Telemetry Systems (Mequon, WI), and Advanced Telemetry Systems (Isanti, MN). Radio package weights ranged from 19.5 to 34.0 g and represented 0.7-1.4% of male body weights and 1.3-1.4% of female body weights. Relocations.--Radio-marked sage grouse were relocated on spring ranges from 10 April to 28 May. Birds were flushed and the location was marked to facilitate habitat measurements. Group size and flushing distance were also noted. An effort was made to flush all birds in the immediate area. Locations were plotted on 7.S-minute U.S.G.S. topographic maps. UTM map coordinates were obtained and used for distance calculations. Average daily spring movements of sage grouse were obtained for 29 male sage grouse during the breeding season. Radio-marked sage grouse in North Park were relocated at approximately weekly intervals from June through September. Four attempts were made to locate radio-marked sage grouse in Moffat County resulting in a limited sample size for the Thornburg Well Lek. Nineteen sage grouse had active radios during the summer months. Lek Counts.--Counts of male and female sage grouse were conducted between 10 April and 28 May. Birds present on leks were counted 3-5 times during a 15-20 minute interval during each lek visit. Counts occurred within 1 hour of sunrise from a distance of 30-1,000 m depending upon weather, access, and observer preference. Numbers of male and female sage grouse were obtained. �Breeding Bird Surveys Breeding bird surveys were conducted during June and on 2 July at the Deer Creek and Perdiz study sites. Transects at Deer Creek were counted 5 times between 1 and 28 June. Transects at the Perdiz study site were counted 3 times (29 and 30 Jun, 2 Jul). Two counts were obtained at the Thornburg Well site but did not constitute an adequate sample. These counts are not included in this report. Counts started 0.5 hour before sunrise and were completed within 2 hours of sunrise. A grid form was used to plot the estimated distance of birds from the transect. Singing males and non-singing individuals were recorded. Calculation of species d~versity, evenness, and richness followed Wiens and Rotenberry (1981). Only singing males were used for calculation of birds/40 ha, relative abundance, species diversity, evenness, and richness on all transects. Counts were averaged and then grouped by burn, burn edge, and unburned. These values were then converted to birds/40 ha. The only exception was the unequal length burn transects at the Deer Creek site. These values were converted to birds/40 ha and then averaged. Transects were slightly altered from those counted in 1988. An additional 500 m transect was established and counted in unburned habitat at the Deer Creek study site. The edge and unburned habitat transects were reduced to 500 m in length at the Perdiz study site. As in 1988, width was limited to 70 m from each side of the transect. Singing and non-singing individuals were recorded. Habitat Measurements Vegetation measurements were obtained from sage grouse spring feeding/loafing sites and from 10 plots within each burn in North Park. Measurements were taken using methods described by Canfield (1941) and Daubenmire (1968). Two 10-m lines were measured at each location. Lines were oriented north-south and east-west centered over sage grouse flush locations or at random locations. Shrubs, forbs, and grasses were estimated to the nearest 5%, if greater than 5%, at 20 0.5-m2 plots (lO/line at I-m intervals). Percentages less than 5% were estimated to the nearest 1%. Canfield's technique was used to measure the canopy and subcanopy while the 0.5-m2 plots were used to examine ground cover at or just above the soil surface. RESULTS AND DISCUSSION Sage Grouse Lek Counts Counts of sage grouse present were obtained for Thornburg Well (n - 6), Deer Creek (n = 5), Fish Hatchery (n - 4), and Perdiz (n - 4) leks (Table 1). Peak male sage grouse counts at Deer Creek were 43% lower than in 1987 (preburn) and 28% lower than in 1988. Low juvenile male recruitment appeared to be responsible for the reduction in male lek attendance. It is difficult to relate this to the burn as counts at 11 of 23 known leks in North Park decreased in lek attendance, ranging from 13 to 63% (~ - 35%) for the 1987-89 �interval. Peak hen attendance attendance. remained consistent with 1988 peak hen Peak male attendance at Perdiz decreased 50% from 1987 to 1989. Other grouse leks in the Perdiz area had varied trends in peak male counts. at Turkey decreased 29% while those at Raven increased 7%. Counts at indicated an increase in peak male attendance of 96%. Counts of males Hatchery remained constant during the 1987-89 interval (+1 male). sage Counts Denmark at Fish Peak male sage grouse attendance decreased slightly at Thornburg Well between 1988 to 1989. This lek was not systematically counted in 1987 but was counted at least once. High counts for male sage grouse in 1987 and 1989 were 17 and 16, respectively. Table 1. Counts of sage grouse on leks, Jackson May, 1989 and 1973-88. Deer Creek High count Males Females N counts Dates of high count Male Female Peak male counts 1988 1987 1986 1985 1984 1983 1982 1981 1980 1979 1978 1977 1976 1975 1974 1973 and Moffat Fish Hatchery counties, Perdiz April- Thornburg Well 13 13 36 27 8 5 16 2 5 4 4 6 9 Apr 16 Apr 12 Apr 12 Apr 18 23 21 45 14 47 66 52 28 43 41 31 36 27 36 35 32 26 16 63 50 67 78 82 97 64 81 69 62 67 11 37 aNo systematic counts, NC - no count. byear of initial location. 7 & 17 May 17 Apr 13 16 6 10 8 21 27 23 8 16b 22 Apr 22 Apr 20 17a 15a Sa NC 8a 8a 20 28 35 32 36b �50 Sage Grouse Relocations Twenty-nine sage grouse were captured and radiomarked during spring 1989. Twelve sage grouse (9 males, 3 females) were captured and radiomarked at Deer Creek. Twelve (10 males, 2 females) were captured and radiomarked at Fish Hatchery. Four males and 1 female were captured and radiomarked at Thornburg Well. No sage grouse were radiomarked at the Perdiz study site in 1989. Survival of radio-marked sage grouse was relatively good during Spring 1989. Eight male sage grouse provided 9-15 locations each at the Deer Creek study site for a total of 55 independent observations. A total of 152 grouse was observed while flushing radio-marked male sage grouse during April and May. Male sage grouse habitat use patterns at Deer Creek were similar to those documented in 1988. Average distances from the lek for breeding season locations was 0.8 km (0.7-1.1 km) in 1989 and 0.9 km (0.2-1.8) in 1988. Areas of observed use were similar between years. Several 1988-89 locations were within meters of each other. The north and east sides of the bench adjacent to the Deer Creek Lek were the most commonly used areas in both years. Use of the burn plot was limited but increased slightly over 1988. Eight of 55 observations of sage grouse were within the burn plot in 1989. In 1988, only 1 of 75 locations was within the burn plot. Two of 3 radio-marked hens at the Deer Creek study area successfully hatched clutches in 1989. All hens nested, but one nest (hen 2341) was destroyed. Average distance from the lek to the 3 nest sites was 2.4 km and ranged from 1.1 to 4.1 km. Accurate clutch size information was not obtained but remains of at least 5-6 eggs were found at each nest site. Both successful hens used meadow areas north and east of the Deer Creek Lek following hatching of clutches. No more than 1 chick(hen was observed. Following initial movements from nest sites, hens with chicks moved only short distances between observations. June locations were obtained for 7 male sage grouse from the Deer Creek Lek. A total of 121 grouse was observed during 44 locations of radio-marked male sage grouse. Radio-marked male 151.059 was captured in 1988 and was not located until after the breeding season. The other 6 males were captured in 1989. Males were located 4-9 times following the breeding season and prior to 1 July. Use areas were similar to areas used by sage grouse in 1988. Average distance from the lek of capture of male sage grouse was 4.8 km and ranged from 2.3 to 8.1 km. Group sizes ranged from 2 to 16 grouse with an average of 4. During the July-September interval ten males and 3 females were relocated at the Deer Creek study site. Average distances from the lek were 5.2 and 3.4 km for males and females, respectively (range 3.0-7.2). As in 1988, use was intensive near meadow areas for most birds. One radio-marked male captured in 1988 was located along the Illinois River drainage west of the Deer Creek Lek. This bird appeared to use the same area as in summer 1988. The radio from this bird was recovered on 15 August 1989. No sign of mortality was observed. Other sage grouse were also located primarily west and south of the Deer Creek Lek, primarily along the Illinois River drainage. Another area of intensive use was observed north and east of the Deer Creek Lek and Owl Ridge, along the Owl Creek drainage and adjacent upland areas. One radio-marked hen was shot during the 1989 hunting season (Band #2341). A total of 450 grouse was seen during 75 observations of radio-marked sage grouse. �-, )L Ten male and 2 female sage grouse were captured and radio-marked at the Fish Hatchery study site in 1989. Three male sage grouse captured in 1988 were present in 1989, although during the 1989 breeding season independent observations were only obtained for 2 of these birds. Spring locations were obtained on a total of 11 male sage grouse from the Fish Hatchery Lek. Fifty independent observations were obtained for male sage grouse during the breeding season. A total of 230 sage grouse sightings was recorded while obtaining independent observations. The average distance from the lek was 1.1 km in 1989 compared to 0.9 km in 1988. Areas of use were similar in both years. Nesting activity was not observed for the radio-marked female sage grouse at the Fish Hatchery study site. Movements from the Fish Hatchery Lek to summer range were similar to those observed in 1988. Ten male sage grouse were located 2-5 times during June for a total of 35 locations. Two hundred and twelve sage grouse were observed during these locations. Group sizes ranged from 2 to 70 birds and averaged 9. The average distance from the lek for 10 male sage grouse was 12.7 km and ranged from 6.5 to 24.7 km. As observed in 1988, 2 male sage grouse (926, 1988; 1149, 1989) moved in excess of 20 km southeast to the Willow Creek drainage northwest of Rand. Ten radio-marked sage grouse (9 males, 1 female) from the Fish Hatchery study site were located in July-September while 2 were not located. Grouse were observed along drainages and adjacent upland areas of the North Platte River, Grizzly Creek, Little Grizzly Creek, Willow Creek, and Chedsey Creek. Average distances from the lek for male sage grouse were 13.0 (range 6.4-25.2) and 4.8 km for the hen. A total of 563 sage grouse was observed on 38 occasions. One radio was recovered just north of the Chedsey Creek drainage (Band #1139). This bird was subsequently shot during the fall hunting season. The hen was also shot during the hunting season. Four male and 1 female sage grouse were captured and radiomarked at Thornburg Well during April 1989. Five male sage grouse captured at Thornburg Well in Spring 1988 were located on and near the lek in 1989. A broken poncho radio package was found on the lek early in the breeding season from male #990. Locations were obtained from 7 male sage grouse. As documented in North Park, breeding season habitat use patterns were similar in 1988 and 1989. Use of the burn was not observed until later in the spring. One male was observed in a remnant patch of sagebrush within the burn on 2 dates in May. A total of 82 sage grouse was observed at 37 locations. Average distance from the lek for male sage grouse during the breeding season was 0.65 km compared to 0.8 km in 1988. Group size averaged 2 male sage grouse and ranged from 2 to 14; single birds were commonly observed. The radio-marked female sage grouse (band 2340) nested about 1 km SE of Thornburg Well Lek. This hen was inadvertently flushed from a nest of 5 eggs when first located. An additional egg was laid and the nest was abandoned. A renesting attempt was also unsuccessful. Following the breeding season, most male sage grouse at the Thornburg Well study site moved east and south. One male (band 2292) moved north, near the Yampa River, and was predated between 16 May and 22 June. Sage grouse were observed in the burn near the lek and in other burned areas. Only 4 radios (3 males, 1 female) were active during July-September at the Thornburg Well study site. Two male sage grouse were not located. This site was visited approximately once per month. Sage grouse were observed to use areas along the Yampa River drainage. Birds were also found in areas south and east of Thornburg Well. Average distances from the Thornburg Well Lek �52 were 7.3 km (range 5.1-9.6) for males and 5.8 km for females. grouse was observed on 6 occasions. A total of 60 Passerines Breeding Bird Survey.--Breeding bird surveys were conducted 5 times at the Deer Creek study site during June. Dates of counts were 16, 20, 26, 27, and 28 June. The 20 June count was an evening count. Density estimates between 1988 and 1989 varied (Tables 2, 3). The maximum number of males observed during all counts was used to derive density estimates. This should be equivalent to the maximum number of breeding pairs/40.5 ha. However, additional analysis of the data is necessary before final conclusions are drawn. Transects at the Perdiz study site were counted on 29 and 30 June, and 2 July. Table 2. Density (males/40.5 ha) of breeding birds observed at the Deer Creek study site, Jackson County, Colorado, summer 1988 and 1989. Data are based on highest number of singing males observed during 3 counts in 1988 and 5 counts in 1989. Species Brewer's sparrow Vesper sparrow Sage thrasher Horned lark Green-tailed towhee Totals 1988 Unburned 1989 % change 6 6 12 8 +9 -23 -67 0 -33 82 68 -17 23 35 6 25 27 2 1988 Burned 1989 % change 6 18 4 10 3 18 10 3 15 3 +200 -44 -25 +50 0 41 49 +20 Density varied markedly between burn and unburned areas. Vesper sparrows and green-tailed towhees had lower densities between burned and unburned transects. Relative abundance and density of horned larks were greater in burned transects at all study sites. Species diversity was greater within the burn transects at Deer Creek but was lower at the wildfire sites. Habitat Measurements Measurements were summarized for male sage grouse locations and 20 burn plots. Averages for most variables appear to be within ranges previously reported for North Park (Schoenberg 1982, Hernandez 1988). The percentage of sagebrush was somewhat lower because of some locations within burns. Vegetation variables measured for spring grouse locations at the Deer Creek study site were similar to those observed in 1988, although percent sagebrush cover was lower than in 1988 (Table 4). Burns were characterized by low vegetation cover although increases were observed for all variables except based on highest number of singing males observed during 5 counts in 1988 and 3 counts in 1989. number of dead plants/m2 (Table 5). Young sagebrush plants were encountered at a higher rate than in 1988. Seventy-seven seedlings were �Table 3. Density (males/40.5 ha) of breeding birds observed at the Perdiz study site, Jackson County, Colorado, summer 1988 and 1989. Data are species 1988 Brewer's sparrow Vesper sparrow Sage thrasher Horned lark Green-tailed towhee 40 12 6 1 6 65 Totals Unburned 1989 X change 1988 43 12 3 0 9 +8 0 -50 -100 +50 3 12 6 6 0 67 +3 27 Edge 1989 Burned 1989 X change X change 1988 23 12 0 0 0 +667 -23 -100 -100 0 0 0 0 3 0 0 0 0 9 0 0 0 0 +200 0 35 +30 3 9 +200 V' �54 observed in burn plots at the Deer Creek site. Heights for these plants ranged from 0.8 to 9.5 cm and averaged 3.2 cm. Average widths were 2.6 cm (range 0.4 - 8.6). Forty-seven sagebrush seedlings were encountered in the Perdiz sample. Average heights were 5.2 cm (range 1.5 - 12.5) and widths averaged 5.8 cm (range 1.2 -16). Table 4. Vegetative site, Jackson County, parametersa at sage grouse use sites, Deer Creek study Colorado, 1988-89. Sagebrush Liveb Deadb 1988 1989 (n = 59) (n - 49) 2.1 (0.4-5.0) 0.5 (0-1.8) Pe r c erit.? 3.2 (1.2-7.8) 0.8 (0.1-2.8) 20.8 (10.1-35.2) 28.2 (3.3-50.9) Ave height, cm Ave width, cm Ave length, cm 34.3 (17.0-72.2) 43.9 (17.2-84.4) 35.7 (11.9-65.3) 25.7 (11.1-55.1) 33.3. (16.2-55.5) Ave space, cmc,d' 75.0 (29.9-321. 8) 52.8 (29.6-105.2) Ave shrub, Xe Ave forb, Xe Ave grass, Xe 9.3 (0.1-21.0) 7.0 (0-24.4) 13.0 (3.4-73.2) aMean (Range). bSagebrush p1ants/m2. CLine-transect data. dDistance between sagebrush eDerived from 0.s-m2 plots. Table 5. 9.8 (2.4-21.5) 7.4 (0.6-21.9) 8.0 (2.1-26.5) plants. Habitat variables8 On burn plots, Jackson county, Colorado, 1988-89. Deer Creek Perdiz 1988 Sag~br~sh LIve Deadb PercentC 3 (1.9-5.3) 0.8 (0-4.8) Ave shrub, Xd Ave forb, Xd Ave grass, Xd 2.5 (0-10.4) 1.3 (0.2-3.4) 5.1 (2.3-7.3) o aMean (Range )• bsagebrush plants/m2. CLine-transect data. dDerived from 0.5·m2 plots. 1989 1988 0.2 (0.1'0.5) 3.9 (2.3-5.6) 0.06 (0'0.2) 2.4 (2.0-3.2) 0.5 (0-2.2) o 1.8 (0-5.6) 2.7 (1.1-5.2) 12.6 (9.1'17.4) 0.4 (0-1.9) 0.7 (0.1-1.9) 3.9 (1.6-5.8) 1989 0.1 (0'0.4) 3 (1.6'3.9) o 1.5 (0'3.5) 1.7 (0'4.8) 14.0 (10.2'21) �55 LITERATURE Amstrup, S. C. 44:214-217. Beetle, A. A. Artemisia. 1980. CITED A radio collar for game birds. J. Wildl. Manage. 1960. A study of sagebrush. The section Tridentatae Wyoming Agric. Exp. Stn. Bull. 368. 83 pp. of Braun, C. E., M. F. Baker, R. L. Eng, J. S. Gashwiler, and M. H. Schroeder. 1976. Conservation committee report on effects of alteration of sagebrush communities on the associated avifauna. Wilson Bull. 88:165171. Bray, O. E., and G. W. Corner. 1972. A tail clip for attaching to birds. J. Wild1. Manage. 36:640-642. Canfield, R. H. 1941. Applications of the line interception sampling range vegetation. J. For. 39:388-394. Connelly, J. W., W. J. Arthur, recently disturbed sites. Daubenmire, 266. R. 1968. transmitters method in and O. D. Merkham. 1971. Sage grouse leks on J. Range Mange. 34:153-154. Ecology of fire in grasslands. Adv. Ecol. Res. 5:209- Frandsen, O. A. 1985. Fire as a management tool in southeast Idaho - a case study. Pages 85-87 in K. Sanders and J. Durham, eds. Rangeland fire effects: a symposium. U.S. Dep. Inter., Bur. Land Manage., Boise, Idaho. Gates, R. J. 1983. Sage grouse, 1agomorph, and pronghorn use of a sagebrush grassland burn site on the Idaho National Engineering Laboratory. M.S. Thesis, Montana State Univ., Bozeman. 135 pp. Giesen, K. M., T. J. Schoenberg, and C. E. Braun. 1982. Methods for trapping sage grouse in Colorado. Wi1d1. Soc. Bull. 10:224-231. Hernandez, E. J. 1988. Response of selected avifauna to prescribed burning in the big sagebrush type. Colorado Div. Wi1d1. Job Progress Rep., Fed. Aid Proj. W-152-R. Apr:105-138. Johnsgard, P. A. 1983. Lincoln. 413 pp. The grouse of the world. Univ. Nebraska Press, K1ebenow, D. A. 1972. The habitat requirements of sage grouse and the role of fire in management. Proc. Tall Timbers Fire Eco1. Conf. 12:305-315. Martin, N. S. 1970. Sagebrush control related occurrence. J. Wi1dl. Manage. 34:313-320. Patterson, R. L. CO. 341 pp. 1952. to habitat The sage grouse in Wyoming. and sage grouse Sage Books Inc., Denver, �56 Schroeder, M. H., and D. L. Sturges. sparrow of spraying big sagebrush. 1975. The effect J. Range Manage. on the Brewer's 28:294-297. Schoenberg, T. J. 1982. Sage grouse movements and habitat selection M.S. Thesis, Colorado State Univ., Fort Collins. Park, Colorado. Swenson, J. E., C. A. Simmons, and C. D. Eustace. 1987. Decrease grouse (Centrocerus urophasianus) after ploughing of sagebrush Biol. Cons. 41:125-132. wal1estad, R. 1975. Male sage grouse Wild1. Mange. 39:482-484. responses to sagebrush Wiens, J. A., and J. T. Rotenberry. 1981. Habitat structure of birds in shrubsteppe environments. Prepared Approved by Lee A. Benson Graduate Research Assistant C1ait E. Braun Wildlife Research Leader by in ~orth 86 ?p. of sage steppe. treatment. J. associations and community Ecol. Monogr. 5:21-41. �JOB PROGRESS State Colorado of: Project: T.J-152-R Work _8_: Plan: Job Title: Period Personnel: Upland Kenneth 5ird Researc~ Job _5_ Population Inventor'! and Habitat in Southeast Colorado Covered: Author: REPORT 01 January M. through 31 December Use by Lesser Prairie-chicker:s 1989 Giesen Dave Clarkson, Steve Wagner, Bryant Will, Fellinger, Ken Giesen, Jennie Colorado Division of Wildlife Slater, Chuck ABSTRACT Lek surveys were conducted on a 41.4-~~2 study site and adjacent area near Pasture lAE of the Comanche National Grasslands in Baca County, Colorado. Numbers of leks and lesser prairie-chickens (Tympanuchus pallidicinctus) declined slightly on the study site although numbers of males counted on all leks surveyed in Baca County increased slightly. There was a strong p osi ri ve corr0.ation between lek density and breeding male density (£ = 0.93) but not between average lek size an~ breeding male density (£ = 0.41). Twenty-nine lesser prairie-chickens (14 males, 15 females) were trapped and banded with 11 males and all females being fitted with radio transmitters. Females dispersed an average of 1.39 km from lek of capture to their nest site although the nearest lek to nest site distance was 0.98 km. Clutch size averaged 10 eggs but: none of the nests of radio-marked hens produced chicks. Calculated average home range size of males was 0.92 km2 and that of females was 3.75 km2. Hens selected taller vegetation and denser sandsage stands for nests than at random sites but preference of males and females for summer feeding and loafing s i t es did not .di f f er from random sites for 7 variables measured. ��POPULATION INVENTORY AND HABITAT USE BY LESSER PRAIRIE-CHICKENS IN SOUTHEAST COLORADO Kenneth M. Giesen Within ~he past century the range of lesser prairie-chickens in North America decreased by 92% (Taylor and Guthery 1980) and the population declined by 974 (Crawford 1980). Although the exact historic distribution and population size are unknown, early reports (Bendire 1892, Judd 1905, Bent 1932, Baker 1953. Sands 1978) suggested lesser prairie-chickens were abundant and widely distributed throughout their range. Aldrich (1963) indicated lesser prairiechickens historically inhabited about 360,000 km2 in 5 states while recent estimates suggest a population of 50,000 birds on 125,000 km2 (Crawford 1980, Taylor and Guthery 1980, Johnsgard 1983). Although evidence suggests lesser prairie-chickens were historically peripheral in Colorado, they were thought to be common to abundant in 6 southeastern counties (Baca, Bent, Prowers, Kiowa, Lincoln, and Cheyenne), anc peripheral in adjacent counties (Loeffler 1983). Recent surveys have documented breeding populations in Baca, Prowers, and Kiowa counties (Hoffman 1963, Loeffler 1983, Rash 1985, this study) and unconfirmed sightings in Lincoln County (T. Mathieson, pers. commun.). The number of known active leks is < 50 and the estimated population is 1,200 to 1,500 birds. Lesser prairiechickens were transplanted into Pueblo County in 1988 and 1989 but the success of the introduction has not been documented. Because of its limited distribution and small population size, the lesser prairie-chicken is classified as a threatened species in Colorado. P. N. OBJECTIVES The objectives of this study are to evaluate lek surveys as indices to population trends, ascertain the accuracy of aerial and ground surveys in detecting leks, describe the seasonal floristic and structural characteristics of lesser prairie-chicken habitats in southeastern Colorado, and contribute to preparation of a recovery plan for lesser prairie-chickens in Colorado. SEGMENT OBJECTIVES 1. Review pertinent literature applicable to the objectives of this study. 2a. Locate all active leks within a 4l.4-km2 primary study area and obtain at least 1 count/week (Mar-May) of all males and females on each lek. 2b. Survey all historic leks in Baca County and obtain at least 1 count of males and females on each active lek. 3. Trap and band lesser prairie-chickens on active leks within the primary study area. Up to 20 will be marked with miniature radio transmitters to f~cilitate their periodic location. �-, /' .") ;-' 4. Locate Record lesser clutch 5. Locate radio-marked movements. 6. Measure vegetation cover height of shrubs, forbs, 7. Compile data, prairie-chicken nests by following radio-marked size, incubation period, and nest fate. birds analyze weekly for estimates of seasonal at grouse use sites and random and grasses will be recorded. results, and prepare annual home sites. progress hens. range a~G VOR and report. METHODS Field surveys were conducted on the Comanche National Grasslands and ad':_cent areas in eastern Baca County from mid-March through June using binocula __ -.,a parabolic microphone listening device, and a trained pointing dog to locate active lesser prairie-chicken leks. Leks known to be active in 1988 were surveyed as were most known historic lek sites. Active leks were visited within 2 hours of sunrise to count grouse and classify them to sex. Lek density was defined as the number of active leks on the 41.4 km2 study area and breeding male density was calculated as the sum of the high counts of males on the study area and expressed as males/km-. " Cannon nets and funnel traps (Giesen et al. 1982, Haukos et al. 1990) were used to capture grouse on leks. Each captured grouse was marked with a numbered aluminum band and a unique combination of colored plastic bandettes. Miniature solar- or batterypowered transmitters (weight 18-24 gms) were attached to all captured females and selected males using a poncho (Amstrup 1980). Radio-marked birds were located using a hand-held 3-element yagi antenna and portable receiver. Birds were approached on foot until they flushed and locations were plotted on topographic maps (scale 1:2400). The minimum convex polygon method (Mohr 1947) was used to calculate home range. Vegetative structure and species composition were measured using line-intercept of canopy cover (Canfield 1941) and a range pole (Robel et al. 1970). Plant nomenclature follows Harrington (1964). Sand sagebrush (Artemisia filifolia) density was measured on O.OOl-ha circular plots. Study Area The primary study area was a 41.4-km1 (16 mi1) area of rangeland on or adjacent to Pasture 1AE of the Comanche National Grasslands in Baca County approximately 20 km east of Campo, Colorado. Included were sections 21-28 and 33-36 of T34S, R44W and sections 1-4 of T35S, R44W. Approximately 1,160 ha was privately owned and was rangeland except for a 16-ha milo field (fallow in alternate years). The topography was rolling hills bisected by Murray and Mitchell draws. Elevation ranged from 1,240 m on the west to 1,070 m on the east. Soils were predominately sandy loams with fine sands in the draws. Topography, grazing, and revegetation efforts have resulted in a diverse vegetative community. Sand sagebrush, broom snakeweed (Gutierrezia sarothrae), and yucca (Yucca glauca) were the predominant shrubs. A variety of grasses occurred with sand dropseed (Sporobolus cryptandrus), 3-awn (Aristida longiseta), sideoats grama (Bouteloua curtependula), and blue grama (~ gracilis) being most widespread. Vegetative structural characteristics of the study area were summarized in a previous report (Giesen 1989). �RESULTS AND DISCUSSION Lek Surveys A total of 283 counts of 25 active leks was obtained in Baca County between 22 March and 25 May 1989 (Table 1). In addition, 8 historic leks were surveyed and found to be inactive. High counts on all leks indicated 241 males, 43 females, and 312 total birds for an average of 12.5 birds/active lek. Hen attendance on leks was not synchronous and a minimum of III females was counted between 31 March and 20 May with most Cn = 79, 71.2%) being observed between 12 and 19 April. Although fewer active leks are being surveyed, the total number of lesser prairie-chickens counted and average number of birds/active lek have increased since the study was initiated in 1986 (Table 2). Since most of the same areas are surveyed each year, this suggests that populations may be increasing. Table 1. Lesser prairie-chicken n Lek 2 3 5 6 7 12 14 15 17 18 25 27 28 33/39 35 37 40 42 86-1 86-3 87-2 87-4 87-5 88-2 88-3 Totals Mean counts 21 24 33 11 9 1 1 7 1 11 1 12 38 11 7 7 7 1 26 7 2 28 - 13 3 283 Count period 22 22 23 25 11 1 29 23 29 29 1 1 30 29 16 16 29 31 30 1989a. lek count data, Baca County, Mar-25 Mar-25 Mar-25 Mar-19 Apr-18 28 Apr 30 Apr Apr-18 05 Apr Mar-21 05 Apr Mar-25 Mar-25 Mar-19 Apr-18 Apr-18 Mar-20 01 Apr Mar-25 Apr- 25 Apr-26 Mar-25 OS Apr Mar-2S Mar-03 May May May May May Apr May May May May Apr Apr May May May Apr May May May Males High count Females 13 9 21 7 16 3 5 17 11 11 6 3 15 10 22 11 13 6 10 1 9 1 2 9 13 10 21 9 20 3 8 21 13 17 7 4 19 14 25 15 16 2 2 5 6 2 5 1 2 2 2 5 1 9 3 12 2 1 241 43 10.5 To t a l s" 12 11 10 10 3 13 9 312 12.5 2.5 aLeks 4, 9, 13, 19/38, 23, 86-2, 87-1, and 88-1 were surveyed birds were observed. brnc1udes males, females, and birds not classified to sex. and no �Table 2. Lesser prairie-chicken lek survey data, Baca County, D birds counted D active 1986-89. ~ Year leks Males Females Totals 1986 1987 1988 1989 31 30 26 25 197 219 202 241 22 22 24 43 261 281 289 312 birds/lek 8.4 9.4 11.1 12.5 Summaries of lek count data since 1977 (when written records became available for analysis) indicate the dynamic nature of leks with many becoming inactive and others being established (Table 3). Fifteen of 57 (26.3%) leks being active one or more years since 1977 were initially located in 1985-89 as a result of more search effort and possibly increasing populations of lesser prairie-chickens. Only 13 of 28 leks (46.4%) active from 1977 to 1980 were still active in 1989, yet the total number of active leks in the area has increased. Because numbers of grouse attending leks fluctuates during the March through May breeding season, and survey timing and effort varied each year, the data (Tables 1, 3) may not reflect actual population changes and should be used only to indicate long-term trends. Analysis of lek surveys and lek count data on the 41.4 km2 study area (Table 4) indicate a strong positive correlation between male breeding density and number of active leks (£ = 0.93) but not between male breeding density and average lek size (£ = 0.41). If the high count of males on leks is a constant proportion of the total population, lek density is a better index to population changes than average lek size. These data support results of prairie grouse population surveys in other states (Cannon and Knopf 1981, Martin and Knopf 1981). These results suggest lesser prairie-chicken population changes are better reflected in total number of active leks rather than average number of birds/lek. Thus, inventory methodology should incorporate plans to document annual status (active/inactive) of historic leks and increase efforts to search for additional leks. Trapping and Banding A total of 27 lesser prairie-chickens (14 males, 13 females) was trapped on 4 of 7 active leks within the primary study area. Two females were trapped on another lek adjacent to the study area. Seven of 13 males classified to age were adults while only 2 of 15 hens were adults. The skewed age ratio of hens may indicate a higher susceptibility of yearlings to trapping. All hens captured after 13 April were yearlings suggesting that adult hens may attain breeding condition first or be dominant to yearlings on leks. �High counts of male lesser prairie-chickens, Table 3. Lek 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 86- 1 86-2 86-3 87-1 87-2 87-3 87-4 87-5 88-1 88-2 88-3 19n 1978 1979 1980 1981 1982 4 18 8 9 24 22 15 1 0 0 7 0 7 17 17 16 2 3 3 5 1" 6 8 NC 15 11 HC HC HC HC 5 13 11 11 0 4 14 HC 0 4 13 16 6 NCa 10 2 7 12 15 11 0 0 0 HC 7 12 10 12 NC 3 HC NC 2 1 6 17 HC 0 1 17 12 15 14 11 0 0 0 0 17 8 9 9 0 0 9 0 0 0 4 19 0 3 9 7 7 0 6 15 7 16 14 6 0 0 0 0 20 8 8 0 0 0 9 0 0 0 3 30 0 6 4 4 7 4 18 14 6 8 6 0 3 12 7 29 19 9 0 0 0 0 14 7 6 0 0 0 10 0 0 0 0 33 0 11 2 4 4 0 10 17 0 6 _:b 0 10 12 Baca County, 19n·89. Year 1983 1984 1985 1986 1987 1988 1989 0 12 11 9 26 14 8 0 0 0 0 16 5 12 0 0 0 9 0 0 0 0 23 0 3 2 3 4 0 9 7 7 23 17 7 0 0 0 0 18 0 11 0 0 2 5 0 0 0 0 21 0 2 3 0 7 7 0 18 6 5 0 0 0 0 0 0 11 0 0 5 9 0 0 HC 9 3 3 18 3 8 0 HC 0 NC 4 0 8 HC HC 7 13 NC NC 0 NC 0 0 6 11 0 0 0 21 0 10 8 18 5 3 14 4 10 2 2 7 5 0 0 13 0 12 3 9 7 7 7 7 3 4 4 NC 12 11 6 23 6 12 0 NC HC HC 2 0 6 POC NC 11 11 NC HC 0 NC NC NC 5 NC 7 20 NC HC HC 0 11 HC 16 HC HC 0 7 6 NC HC HC HC NC HC 12 0 0 NC 13 9 0 21 7 16 HC 0 0 NC 16 2 0 17 6 9 HC HC NC HC 5 0 10 NC NC 4 10 NC NC 0 HC 2 NC 2 0 0 12 0 0 0 9 HC 9 0 0 13 0 0 0 16 7 12 7 10 4 0 0 16 0 0 0 0 2 0 0 0 10 0 12 2 11 8 3 0 5 0 0 1 15 6 7 0 NC 6 0 0 17 0 NC 9 0 8 HC 18 0 18 7 0 9 0 10 HC 5 NC 0 11 5 8 0 0 0 7 5 aHO bLek count. not yet located. 0 HC 9 4 3 5 0 0 NC NC 3 0 5 17 HC 11 11 0 HC NC HC 0 HC 6 NC 3 15 HC HC HC HC 10 HC 22 HC 11 0 0 13 HC 6 HC HC NC HC 10 0 0 0 12 2 �Table 4. Lek count trends of lesser prairie-chickens study area, Baca County, Colorado, 1980-89 n n Year leks males 1980 1981 1982 _983 1984 1985 1986 1987 1988 1989 6 6 6 6 4 5 7 8 9 7 59 55 59 65 46 46 75 74 100 82 ~ males/lek 9,8 9.2 9.8 10.8 ll.5 9.2 10.7 9.2 11.1 ll.7 on a 41.4-km2 Breeding density (males/km:) . ", (16 m i. -,1 Lek dens it:r 1.42 1.33 1.42 1.57 1.11 1.ll 1.81 1. 79 2.42 1.98 0.14 0.14 0.14 0.14 0.10 0.12 0.17 0.19 0.22 0.17 Eleven males and all females were fitted with poncho-mounted mlniature radio transmitters to facilitate their periodic relocation. Although transmitters were not observed to have detrimental effects upon grouse, they may have increased predation as only 7 marked grouse were known to have survived at least 3 months (Table 5). Increased predation of radio-marked birds has been reported in other studies (Herzog 1979, Warner and Etter 1983, Hines and Zwickel 1985, Marks and Marks 1987, Haukos 1988). Table 5. Colorado, Fates of radio-marked 1989. lesser prairie-chickens n in Baca County, birds Fate Males Females Dispersal or radio failure Transmitter lost from bird Depredated Survived> 3 months 1 4 2 4 4 1 6 4 5 5 8 8 II 15 26 Totals Totals Nesting Fates of 15 hens were ascertained using radio telemetry. Two hens were killed by predators prior to nesting, signals from 3 hens were lost within 2 weeks, 3 hens were located periodically but did not localize and no nests were found, and 7 hens were known to nest. Predation caused failure of all nests and none �of the hens was known to attempt renesting. Nests were only visited once to ascertain clutch size and were discretely marked with flagging 10 m from the nest. Predation was usually not detected until the hen was absent from the nest for 2 consecutive radio relocations (usually a week or more). Thus, the identity of predators was difficult to ascertain. None of the hens was killed during incubation. The average distance from capture site on leks to 7 nests was 1.39 krn (range 0.79 - 2.84 krn). The average distance to the nearest lek was 0.98 krn (range 0.36 - 1.76 km) with 5 of 7 hens nesting closer to a lek different from that of capture. Sell (1979) reported a similar range of movements between leks and nest sites. If hens nest within their spring home range, we can assume that the closest lek may not be the one selected for mating. Clutch size ascertained from 6 nests averaged 10.0 eggs (range 6 - 11) but the clutch of 6 eggs may not have been complete. Haukos (1988) reported clutch sizes from 3 to 11 but smaller clutches may have been incomplete or the result of renests. Habitat Characteristics Lek Sites Vegetative compos~t~on at 7 lek sites was recorded using a visual estimate of species composition. Density and height of sandsage was measured along transects radiating from the center of the 1ek to the periphery along the 4 primary compass directions. Short grasses predominated with forbs and shrubs less common (Table 6). The density of sands age was 15.9% of that measured on random transects in the study area (Giesen 1989) although height was similar. Table 6. Vegetative County, Colorado. Lek characteristics Sandsa~e DensityA ~ hgt. at lesser prairie-chicken Bogr 10 65 25 20 5 5 0 889 111 111 0 1556 111 n/a 37.4 37.0 47.0 n/a 27.3 64.0 45 10 30 50 20 Ave. 397 42.5 22.1 in Baca Ve~etative com£osition~ Bocu Spcr Sihy Arlo Buda 2 3 5 27 28 86-1 87-4 leks 5 10 5 5 10 5 10 5 5 40 5 5 40 55 40 90 14.3 17.1 5.0 aplants(ha. bpercent of vegetative cover. cBuda - Buchloa dactyloides, Bogr - Bouteloua ~racilis, curtependu1a, Spcr - Sporobolus cryptandrus, Sihy - Sitanion Aristida lon~iseta, FoSh - forbs & shrubs. 9.3 21.4 Bocu - ~. hystrix, Arlo FoSh 10 10 15 15 5 15 10 10.7 - �Nest sites Seven habitat variables were measured at each nest site. Although complete statistical analysis of the dat~ has not been completed, height-density, heights of shrubs, forbs, and tall grasses, and sandsage density were higher at nest sites than at random sites. Percent bare ground did not differ between nests and random sites. Because nesting occurs prior to new growth of forbs and grasses, the quality of residual cover may limit nest sites. Selection of taller clumps of residual cover for nesting by lesser prairiechickens has also been reported in other areas (Copelin 1963, Suminski 1977, Davis et al. 1979, Haukos 1988). The primary factor affecting residual vegetation height on the Comanche National Grasslands appears to be livestock grazing. Grazing management to benefit lesser prairie-chickens might incluce provisions to minimize grazing beyond the growing season or to remove cattle from certain pastures when a certain height-density (3 dm) is reached. These hypotheses should be tested experimentally. Summer Range Preliminary vegetative analysis of grouse flush and random sites indicated no differences (f > 0.05) in mean values for the 7 habitat variables measured. Because the distribution of all variables were not normally distributed, it is possible that grouse are avoiding extremes of habitat variables and using most of the remaining habitats. It is also likely that the study area represents the best habitats available and that little selection (or avoidance of poor habitats) is necessary. If similar habitat preference measurements were conducted in lower quality habitat, in more patchy habitat, or at a different time of year (i.e., winter) a difference between use and random sites might occur. A complete analysis will be provided in the final report after suitable statistical tests have been conducted. Home Range Home range sizes were calculated for 9 males a~i 7 females which were observed for more than 30 days (Table 7). Although males tended to have smaller home ranges than females (0.92 ± 0.76 vs 3.75 ± 2.88 km2), differences were not significant. Because no radio-marked hen was successful in hatching a clutch of eggs they may have tended to move greater distances in summer than would hens with chicks. Hens also tended to summer alone with little apparent home range overlap whereas males were often located in small flocks and tended to remain adjacent to leks where they displayed. �Home range size of radio-marked Table 7. County, Colorado, 1989. Band 299 403 404 405 406 407 408 411 413 418 419 422 423 424 425 426 Sex Age 2+ 112+ 11111112+ 12+ 1- in Baca Time interval Home ran~e size (km+) 06 14 16 21 15 18 17 18 18 25 25 05 03 05 06 07 M M F F M F M F F M F F M M M M ? lesser prairie-chickens Apr -13 Apr-18 Apr-2l Apr-21 Apr-ls Apr-25 Apr-20 Apr- 21 Apr-21 Apr-ls Apr-25 May-09 May-21 May-26 May-2s May-11 Jul Aug Sep Sep Aug May Jun Sep Sep Aug May Jun Sep Ju1 Ju1 Jul 0.08 1. 53 2.31 6.29 1. 23 0.35 0.08 6.68 7.10 2.51 0.76 2.79 0.86 0.46 0.68 0.85 LITERATURE CITED Aldrich, J. W. 1963. Geographic Wildl. Manage. 27:529-545. Amstrup, S. C. 1980. 44:214-217. Baker, M. F. 1953. Misc. Pub1. 5. orientation A radio-collar Prairie 68pp. chickens of American for game birds. of Kansas. Tetraonidae. J. Wildl. Univ. Kansas J. Manage. Mus. Nat. Hist. Bendire, C. E. 1892. Life histories of North American birds with special reference to their breeding habits and eggs. U. S. Natl. Mus. Spec. Bull. l. 446pp. Bent, A. C. 1932. Life histories Natl. Mus. Bull. 162. 490pp. Canfield, R. H. 1941. range vegetation. of North American gallinaceous Application of the line intercept J. For. 39:338-394. Cannon, R. W., and F. L. Knopf. prairie grouse populations. method birds. in sampling 1981. Lek numbers as a trend index to J. Wildl. Manage. 45:776-778. Copelin, F. F. 1963. The lesser prairie-chicken Wild1. Conserv. Dep. Tech. Bull. 6. s8pp. in Oklahoma. U.S. Oklahoma �Crawford, J. A. 1980. Status, problems, and research needs of the lesser prairie chicken. Pages 1-7 in P. A. Vohs and F. A. Knopf, eds. Proc. Prairie Grouse Symp. Oklahoma State Vniv., Stillwater. Davis, C. A., T. Z. Riley, R. A. Smith, H. R. Suminski, and M. J. wisdom. 1979. Final report: habitat evaluation of lesser prairie chickens in eastern Chaves County, New Mexico. New ~exico State Univ. Agric. Exp. Stn., Las Cruces. l41pp. Giesen, K. M. 1989. Population inventory and habitat use by lesser pralrlechickens in southeast Colorado. Job Prog. Rep., Colorado Div. wildl. Fed. Aid Proj. w-152-R. Apr:37-49. _____ , T. J. Schoenberg, grouse in Colorado. and C. E. Braun. 1982. Methods wildl. Soc. Bull. 10:224-231. Harrington, H. D. 1964. Manual of the plants Swallow Press, Inc., Chicago. 566pp. for trapping of Colorado. Sage Books, Haukos, D. A. 1988. Reproductive ecology of lesser Thesis, Texas Tech. Univ., Lubbock. 81pp. prairie-chickens. ______ , L. M. Smith, and G. S. Broda. 1990. Spring prairie-chickens. J. Field Ornitho. 61:20-25. trapping E., and F. C. Zwickel. 1985. Influence grouse. J. Wildl. Manage. 1050-1054. Hoffman, D. M. 1963. The lesser Manage. 27:726-732. Johnsgard, P. A. 1983. Lincoln. 4l3pp. Judd, prairie The grouse chicken of the world. of radio packages in Colorado. Univ. M.S. of lesser Herzog, P. W. 1979. Effects of radio-marking on behavior, movements, survival of spruce grouse. J. wildl. Manage. 43:316-323. Hines, J. blue sage and on young J. wildl. Nebraska Press, S. D. 1905. The grouse and wild turkeys of the United States and their economic values. U.S. Dep. Agric., Biol. Surv. Bull. 24. 55pp. Loeffler, C. 1983. The status and management of the lesser prairie chicken Unpupl. Rep., Colorado Div. wildl., Colorado Springs. 9pp. in Colorado. Marks, J. S., and V. S. Marks. 1987. Influenc2 of radio-collars of sharp-tailed grouse. J. Wildl. Manage jl:468-47l. Martin, S. A., and F. L. Knopf. 1981. Aerial survey chicken leks. Wildl. Soc. Bull. 9:219-221. Mohr, C. O. 1947. Table of equivalent populations mammals. Am. Midl. Nat. 37:223-249. of greater of North on survival prairie American small �) Rash, M. T. 1985. Survey of the lesser prairie-chicken in Colorado, 3 April - 25 May 1985. Unpubl. Rep., Colorado Div. Wildl., Colorado Springs. 22pp. Robel, R. J., J. N. Briggs, J. J. Cebula, A. D. Dayton, and L. C. Hulbert. 1970. Relationships between visual obstruction measurements and weight of grassland vegetation. J. Range Manage. 23:295-297. Sands, J. L. 1978. Game bird studies. Performance Rep., Proj. W-104-R-19, New Mexico Dep. Game Albuquerque. 5pp. Sell, D. L. 1979. Spring and summer movements and habitat pra~r~e chicken females in Yoakum County, Texas. M.S. Tech. Univ., Lubbock. 41pp. and Fish Proj. use by lesser Thesis, Texas Suminski, H. R. 1977. Habitat evaluation for lesser prairie-chickens eastern Chaves County, New Mexico. M.S. Thesis, New Mexico State Las Cruces. 80pp. in Univ., Taylor, M. A., and F. S. Guthery. 1980. Fall-winter movements, ranges and habitat use of lesser prairie-chickens. J. Wildl. Manage. 44:521-524. Warner, R. E., and S. L. Etter. radiomarked hen ring-necked 47:369-375. Prepared 1983. Reproduction and survival of pheasants in Illinois. J. Wildl. Manage. by Kenneth M. Giesen Wildlife Researcher B ��71 JOB FINAL REPORT State of: Colorado Project: Work Plan: Job Title: 12 Job 15 Chronology of Breeding and Nesting Activities Relation to Timing of Spring Hunting Seasons Period Covered: Author: Upland Bird Research W-152-R of Wild Turkeys in 01 July 1985 through 31 June 1990 Richard W Hoffman Personnel: T. D. Abell, J. L. Aragon, C. E. Braun, R. W. Hoffman, R. L. Holder, B. S. Linkhart, T. B. Lundt, R. K. Mueck1er, and T. J. Spezze, Colorado Division of Wildlife ABSTRACT Gobbling, nesting, roosting, and movement activities of Merriam's wild turkeys (Meleagris gallopavo merriami) were studied in southcentra1 Colorado during spring 1986, 1988, and 1989. Mean dates for onset of incubation were 14 (1989), 18 (1986), and 21 May (1988). Peak of incubation occurred between 16 and 25 May, after the spring hunting season. Nesting success was only 8% for subadults and 22% for adults; most (92%) subadults and 38% of the adults either did not attempt to nest or lost their clutch during the laying period. Few (7%) hens attempted to renest. Average clutch size was 10.4 ± l.9(SD) eggs; 89% of the eggs in successful nests hatched. Gobbling was sporadic and differed among males. Subadult males seldom gobbled. Adult males gobbled more (~= 0.007) in morning (AM) than evening (PM), more (~= 0.003 for AM, ~ = 0.006 for PM) on than off the roost, more (~ = 0.016) in the absence than presence of hens, and more during than before (~ = 0.01) or after (~ = 0.034) the hunting season. Two peaks of gobbling were identified.. The 'second peak (11-20 May) approximated peak incubation. The gobbling and nesting data' supported a late April to late May season. Subadult males moved farther (8.7 ± 3.1 km, ~ = 0.03) from winter to breeding areas and occupied larger (12.3 ± 4.9 km2, ~ < 0.01) spring home ranges than adult males (movements = 5.3 ± 3.8 km, home range = 5.2 ± 3.3 km2). Adult (10.4 ± 5.5 km) and subadult (10.4 ± 5.9 km) females moved similar (~ = 0.91) distances. Adult females moved farther (~ < 0.01) than adult males, but subadult females did not move farther (~ = 0.61) than subadult males. The median distance between morning and evening roosting sites used on the same day was 996 m for subadu1t males and 1,073 m for adult males. The frequency with which adult males were found at previously-used spring roosts was 19%. Subadult males returned to the same roosts more often (29%, ~ = 0.14) than adult males. Departure and roosting times during the spring hunting season indicated shooting hours should start at sunrise and end one-half hour before sunset to discourage roost shooting. Based on a 100% survey conducted from 1986 to 1988, an average of 3,888 spring �72 hunters harvested 603 turkeys for a success rate of 16%. In comparison, 1,318 fall hunters harvested 315 turkeys annually for a success rate of 24%. Las Animas County was the leading harvest area. The legal harvest of bearded hens accounted for < 3% of the total spring harvest. Merriam's wild turkeys dominated wing samples and were harvested in 29 of the state's 63 counties. Rio Grande wild turkeys (M. g. intermedia) were harvested in 10 counties, including 3 counties where both subspecies were harvested. �73 RECOMMENDATIONS 1. The spring hunting season for Merriam's turkeys should open in late April and extend through late May to minimize disturbance during peak of mating, bracket peak incubation, and include the second peak of gobbling. 2. Following recommendations of Schmutz and Braun (1989), timing of the spring hunting season for Rio Grande turkeys should be from mid-April to mid-May. Because Rio Grande's primarily occur in eastern Colorado (i.e., east of 1-25) and Merriam's in western Colorado, and because most hunting of Rio Grande's is by permit only, seasons could be structured to open and close on different dates corresponding to the peak incubation periods of the 2 subspecies. 3. A statewide wing collection program should be implemented to monitor age, sex, and subspecies composition of the harvest. The feasibility of a mandatory checking program, similar to that for black bears, should be investigated. 4. Areas open to hunting of Rio Grande's should be by permit only so that harvest and hunter activity for Rio Grande's can be monitored separately from Merriam's. Hunters successful in drawing a permit should be restricted to hunting in the area where the permit is valid. A hunter successful in harvesting a Rio Grande turkey on a permit area should be allowed to pu~chase another license to hunt Merriam's turkeys in any nonpermit area. 5. A 100% survey of license buyers following the end of the spring enhanced by the implementation license agents must be directed weeks after the season ends. 6. A quantifiable method~for separating Rio Grande and Merriam's wing characteristics needs to be developed and tested. 7. The almost total lack of reproductive output by yearling hens and the apparently low nesting rate and success of adult hens requires further study. 8. Managers should avoid releasing Rio Grande turkeys into areas where they may come in contact with native populations of Merriam's turkeys. 9. Shooting hours during the spring season should start at sunrise and end one-half hour before sunset to discourage roost shooting and promote ethical hunting practices. 10. Use of gobbling counts to monitor relative abundance and trends in population growth is questionable; however, gobbling surveys can be used to detect presence or absence when measuring range expansion of introduced populations. Gobbling surveys should be conducted while the birds are still on the roost, preferably during the 45 minutes preceding sunrise. Tape recorded calls could be used to stimulate gobbling. should be conducted within 4 weeks and fall seasons. This process has been of the 2 license system. Accordingly, to return all license stubs within 2 turkeys by ��75 CHRONOLOGY OF BREEDING AND NESTING ACTIVITIES OF WILD TURKEYS IN RELATION TO TIMING OF THE SPRING HUNTING SEASON Richard W. Hoffman INTRODUCTION Wild turkeys have been legally hunted in Colorado since 1949 (Burget 1957). Fall-only hunting was permitted until 1964 when the first spring season was held: subsequent spring seasons were held in 1965, 1967, 1968, and 1970 (Colo. Div. Wi1d1. 1984). A continuous 23 to 30-day season, opening in mid-April and extending through early to mid-May, has been held every year since 1973,except in 1990, when the season was extended 2 weeks in May. Fall seasons have ranged from 9 to 16 days, opening in mid- to late September and closing in early to mid- October. In 1990, the fall season was lengthened to 30 days by opening a week earlier in September and closing a week later in October. In 1973, an estimated 1,301 hunters (spring = 496, fall = 805) harvested 265 turkeys (spring = 64, fall = 201). By 1983, 4,894 hunters (spring = 3,030, fall = 1,864) were harvesting 1,147 turkeys (spring = 645, fall = 502). The Colorado Division of Wildlife (CDOW) responded to this growing demand by focusing their management efforts on (1) restoring populations of Merriam's wild turkeys in western Colorado, and (2) establishing new populations of Rio Grande wild turkeys in eastern Colorado. The success of transplant programs plus increases in hunter participation generated a need for more refined data upon which to base management recommendations. Paramount was the need for more reliable estimates of harvest by area, subspecies, age, and sex, and for better documentation of the chronology of breeding and nesting activities. Previous studies of wild turkeys in Colorado (Burget 1957; Hoffman 1962, 1966, 1968, 1973; Myers 1973) failed to address these needs. Thus, no quantitative data existed to justify the timing and length of spring seasons and, as a result, seasons were set more on tradition than biological evidence. P. N. OBJECTIVES 1. Document timing of winter flock dispersal, onset of gobbling, peaks of gobbling, nest initiation, onset of incubation, and peak of hatch in relation to timing of the spring hunting season. 2. Describe the gonadal cycle of females and compare the reproductive condition of females in relation to timing of the spring season. 3. Measure the abandonment rate of incubating human disturbance around the nest. 4. Monitor hunter activity and harvest females to varying levels of of wild turkeys on a statewide basis. �76 STUDY AREA Trapping was confined to Longs Canyon and 2 tributary canyons, Sowbelly and Martinez, located approximately 17 km southwest of Trinidad, Colorado in Las Animas County. From here, radio-marked birds ranged over 448 km2 of surrounding areas during the breeding season. This area was bounded by 1-25 on the east, Lorencito Canyon on the west, Colorado Highway 12 on the north, and the Canadian River in New Mexico on the south. This topographically diverse area varied in elevation from 1,800 to 2,600 m and was intersected by 4 large canyons in excess of 30 km in length, each with numerous side canyons and adjacent smaller canyons. Major vegetation types included pinyon pine-juniper (Pinus edulis-Juniperus spp.), mountain shrub, and ponderosa pine (f. ponderosa). The mountain shrub type was dominated by Gambel oak (Quercus gambelii), which extended into the pinyon-juniper and ponderosa pine types. Douglas-fir (Pseudotsuga menziesii) and white fir (Abies concolor) occurred in association with ponderosa pine, primarily on north slopes. Over 95% of the area was privately owned. Human activity was minimal. Use of private lands was limited to cattle grazing, some logging, and recreation. METHODS Trapping, Marking, and Radio-tracking Turkeys were baited with oat hay and corn, and livetrapped with drop nets or cannon nets during February and March 1986, 1988, and 1989. No birds were trapped in 1987. Captured birds were classified to age and sex (Hoffman 1962), and banded with serially numbered aluminum leg bands. Numbered and color-coded (by year) Allflex livestock eartags were attached to the patagium. Ages were recorded as subadult (8-10 months) or adult (>18 months). Body weight and length of primaries, carpal, spur, and beard were measured on each bird. One hundred and forty-seven birds (16 adult males, 10 subadult males, 101 adult females, 20 subadult females) were equipped with lithium battery powered transmitters (Models HLPB 2750 and 2l20-LD, Wildlife Materials, Carbondale, IL) attached with a poncho collar (Amstrup 1980) or tail-clip (Bray and Corner 1972). The poncho radio package weighed < 40 gm, the tailclip package < 35 gm. Tracking was conducted from the ground using a 3element Yagi antenna and Telonics TR-2 receiver. All locations were verified by visual observation and recorded to nearest 50 m as Universal Transverse Mercator coordinates. Two aerial searches were conducted each year between late April and late May for birds not found during ground searches. Birds found during aerial searches were subsequently located from the ground. Nesting Activity Flocks containing radio-marked birds were monitored a minimum of 3 times/week beginning in late February to determine the period of flock dispersal. Locations of radio-marked hens following flock break-up varied depending on how far they moved from wintering to breeding areas. Birds moving longer distances were located less frequently because they required more search time to find. During May, hens were located once every 3-5 days to minimize disturbance. All nests were located after incubation had begun. Suspected nest sites were circled and flagged from >30 m away. Some nests were visually observable from this distance. Others were monitored but not approached for �77 30 days unless the radio-signal indicated the hen was gone. Nest sites were visited almost daily as the anticipated hatch date approached. Onset of incubation was estimated by backdating 28 days (Bailey and Rinell 1967) from date of hatch. Most hens were located often enough just before and during the early stages of incubation to approximate within 3 days of when they started incubating. Onset of incubation was not calculated for unsuccessful hens located on nests during later stages of incubation. Clutch size, fertility, and nest success were determined from egg shell characteristics after eggs hatched or after the nest was abandoned or depredated. Differences among years for mean dates of initiation of incubation were tested using ANOVA. Gobbling Activity Gobbling indices were conducted from 1 April to 15 June and categorized as preseason (-1-15 Apr), season (-16 Apr-IS May), and postseason (-16 May-IS Jun). Opening and closing dates of the hunting season varied by 3 days over the study period. An attempt was made to conduct 3 valid indices/week/time period (AM and PM). A gobbling index was considered valid if (1) positive identification was made of the radio-marked bird that was gobbling, (2) the bird was not disturbed before or during the index, (3) the time the bird left (AM index) or went (PM index) to roost was known, (4) the index included time on and off the roost, and (5) it was known whether the bird was alone, or associated with other males and/or females. An index lasted 1 hour from one-half hour before to one-half hour after sunrise (AM index) or sunset (PM index). The l-hour period was divided into time spent on and off the roost and whether females were present or absent. Roosting times were determined by observing or hearing the birds fly to or from the roost. Presence of hens was ascertained from sightings or calls heard during the index or by locating and observing the birds after the index. In the case of simultaneous gobbling bouts, it was assumed the radio-marked male was participating. Gobbles of subadult males were incomplete and higher pitched than gobbles of adults. Radio-marked males were monitored on a rotating basis with the initial order being randomly selected. If, for example, male A could not be located on the day it was to be monitored, then the next male (B) on the list was indexed. Priority was then given to finding male A and doing an index on male A during the time period male B was supposed to be indexed. This order was adhered to as best possible. However, some males were indexed less than others because they were more difficult to find on a regular basis. For AM indices, the male was located on the roost the evening before. Males selected for a PM index were located at least 1 hour before sunset. Gobbling data were totaled for each radio-marked male for each category of comparison (i.e., on and off the roost, hens present and hens absent, AM and PM, etc.) and converted to gobblesjhour. For example, if 200 gobbles (150 on and 50 off roost; 20 total gobbles during preseason) were recorded during 12 AM indices (720 min) on male A, 4 each during the preseason, season, and postseason totaling 252 minutes on and 468 minutes off the roost, then the preseason AM gobbling rate for male A was calculated as total gobbles recorded during the 4 preseason AM indices (20) divided by total minutes of observation (240) times 60 = 5 gobblesjhour. The on roost AM gobbling rate was calculated as total gobbles on the roost (150) divided by total minutes of observation on the roost (252) times 60 = 36 gobbles/hour. �78 The Wilcoxon signed rank test was used to test the null hypothesis of no difference in gobbling on and off the roost, and in the presence or absence of hens. The same procedure was used to compare gobbling rates during the preseason, season, and postseason, and before, during, and after the peak period of incubation. Control of the overall error rate for these comparisons was maintained by use of the Bonferroni inequality. Gobbling of adults between years (1986 and 1989) was compared using the Mann-Whitney Wilcoxon test. Roosting Activity Roosting sites of males were located in conjunction with conducting gobbling indices. Roosting times were determined by observing or hearing the birds fly to and from the roost. Distances between roost sites were calculated from consecutive locations (same day) and for locations ~ 3 days apart. A roost site was considered reused if the same bird was located within 150 m of a previous roost location. The Kruskal-Wallis test was used to test the null hypothesis of no difference in roosting times, and no difference in distances between roosting sites among males within an age class. Comparisons between age classes were made using the Mann-Whitney-Wilcoxon test. The Wilcoxon signed-rank test was used to compare median distances between roost sites for the same male during preseason, hunting season, and postseason periods. Frequency of use of previously-occupied roost sites by adults and subadults was compared with a chi-square 2 x 2 contingency table. Movements and Home Range Harmonic mean transformation (HMT) (Dixon and Chapman 1980) was used to estimate spring home range size for males that survived from 1 April to 15 June and were located ~ 20 times during this period. Home range size was calculated based on the 90% contour of area using the computer program MCPAAL (Stuwe and Blowhowiak 1986). Minimum convex polygon (MCP) (Mohr 1947) ranges were also computed for comparative purposes using the same computer program. Movements from wintering to breeding areas were measured as the minimum straight line distance between the winter trap site and the arithmetic center of the spring home range (males) or the nest site (females). Mean movements and home range sizes were compared using ~ tests. Permits, Questionnaires, Hunters were seasons: 1. required and Wing to obtain Collections 1 of 2 types of permits during spring and fall Special Unlimited Hunting Permit - Unlimited in number and free of charge, these permits were available to any holder of a valid turkey license. Whereas the license could be purchased from any license agent, permits were only available from CDOW offices either on a walk-in basis or by mail application. The special unlimited permits were valid for one season (spring or fall). Unsuccessful spring hunters could hunt in the fall without purchasing a new license, but before doing so, they were required to obtain another permit valid for the fall season. Successful spring hunters who wanted to hunt the fall season needed to purchase another license in addition to obtaining a special unlimited fall permit. By requiring spring and fall permits, hunters could be categorized as spring only, fall only, or spring-fall hunters and surveyed accordingly. �79 Special unlimited permits for the spring season were available from 1 March through the end of the season; those for the fall were available from 1 August to the end of the season. Special unlimited permits were valid for all areas not requiring a limited permit. 2. Limited Hunting Permits - Limited in number, free of charge, and available by public drawing. Only mail applications were accepted for limited permits. The drawing and issuance of permits was handled through the Denver office. Hunters could apply for a limited permit without first purchasing a license. However, if they succeeded in drawing a limited permit, they needed to purchase a license before going hunting. Drawings were held in late March and late August for the spring and fall seasons, respectively. Limited permits were only valid for the area, season, and time period indicated on the permit. Holders of a limited permit were required to obtain a special unlimited permit if they hunted outside the area for which their limited permit was valid. Consequently, some hunters obtained 2 permits and were subsequently mailed 2 harvest questionnaires. This problem was identified as the questionnaires were processed and duplicates were excluded. Questionnaires were mailed to all permit holders immediately after the spring and fall seasons. Non-respondents were mailed a followup questionnaire approximately 3 weeks later. Mean values calculated from responses to the second mailing were used to project answers for those permit holders not responding to either questionnaire. Every hunter that obtained a limited or unlimited permit was also issued a wing envelope coded by permit number. The instructions on the envelope requested each successful hunter to (1) complete the questionnaire printed on the envelope including their name, address, time of harvest, and location of harvest (county, small game management unit, and nearest town), and (2) to remove the least damaged wing and 3 or 4 breast feathers as depicted by 2 schematic diagrams, place them in the envelope, and mail the postage-paid envelope. Envelopes were addressed to the Wildlife Research Center in Fort Collins. Upon receipt, wings were frozen until processed. Information provided by hunters was transcribed onto a standardized form. The envelope's contents were examined to determine if both a wing and breast feathers were enclosed. Samples were identified to subspecies and classified to age and sex. Whenever possible, the following measurements and feather characteristics were recorded for each wing: length, condition (growing, fully grown, empty, broken, worn, pointed) and status (adult or juvenal) of primaries I through X (numbered proximal to distal), quill diameter of P IX and X at their insertion into the follicle, stage of primary molt, carpal length, and status (adult or juvenal) of the first secondary and tertials. Since the range of the Merriam's and Rio Grande wild turkey does not overlap in Colorado, except possibly along the Arkansas River west of Pueblo, the 2 subspecies were identified from wing samples based on the location of harvest. However, inspection of the wings suggested that subspecies could be distinguished by wing color. Rio Grande's tended to have wider black bars and narrower white bars on the primaries than Merriam's, thus, giving the wing a darker appearance. Sex was ascertained by presence of buffy (female) or black (male) tipping on the breast feathers (Hoffman 1962). Wings were assigned to age classes based on the shape, color, wear, and barring pattern of primaries IX and X (Hoffman �80 1962). Juvenal primaries IX and X were pointed, grayish-brown, and lacked white barring near the tip. Comparatively, adult primaries IX and X were rounded and black or blackish-brown, with white barring extending almost to the tip. Subadults possessed the outer primaries characteristic of juveniles except they were faded and worn as a result of being retained longer. Wings obtained from the spring season were classified as adults (> 22 months) or subadults (10-11 months). Those from fall were separated into 3 age classes: adults (> 26 months), subadults (14-16 months), and juveniles « 6 months). RESULTS Capture and marking Two hundred and thirty-nine turkeys (1986 = 99, 1988 = 86, 1989 = 54), including 18 adult males, 145 adult females, 50 subadult females, and 26 subadult males, were trapped in February and early March using drop nets (129), cannon nets (106), or clover traps (4); 141 were equipped with transmitters and released at the trap sites (Table 1). Six birds died as a result of trapping. Efforts to trap adult males in 1988 were unsuccessful. No adult males were observed at the bait sites and no flocks of adult males consistently remained in one area where they could be attracted to bait. Consequently, only subadult males were trapped and monitored in 1988. Table 1. Colorado, Wild turkeys trapped and equipped with radios in Longs Canyon, 1986, and 1988-89. Females Year 1986 1988 1989 Adult Males Subadult Adult 4 7 3 13 o 9 Subadult o 10 o Totals 50 52 39 aOne additional adult hen radio-marked in 1986 was monitored in 1988. bFive additional adult hens radio-marked in 1988 were monitored in 1989. In 1987, trapping operations were initiated in January and continued through mid-April. Except for a flock of 20-30 birds in Sowbelly Canyon, no other turkeys or sign were found in Longs Canyon or any of its tributary canyons. Efforts to trap birds in Sowbelly Canyon were unsuccessful as they could not be attracted to bait sites. Instead, they preferred to feed on hillsides rather than in canyon bottoms where they could be trapped. Several different baits were offered to no avail. Cattle were also a problem as they consumed the oat hay and trampled the bait site, including the cannon nets and wire leads. The lack of use of bait sites was attributed to an abundant supply of pinyon nuts. �81 Bait sites were placed at other known turkey use areas in Longs, Colorow, Saruche, Martinez, and Little Martinez canyons. No birds were observed at any of these sites. Flocks were found near Lake Dorothey and Spanish Peaks. However, because of access and landowner problems, it was not considered feasible to trap these flocks. In addition, the resulting data would not have been directly comparable with that collected in 1986. It was considered better to skip a year and try to trap at the same sites in 1988 than to trap at another location in 1987. Trapping operations were terminated on 1 April 1987, which was the latest date to trap and still meet the objectives of the study. Physical Characteristics Twenty four percent (35/145) of the adult hens and none of the subadult hens captured had beards. Average beard length for adult hens was 137 ± 49(SD) rom. The shortest beard was 35 rom and was clearly visible through the breast feathers. Comparatively, beard length for adult and subadult males averaged 219 ± 18 rom and 64 ± 17 rom, respectively. Weights of adult males did not differ (f = 0.52) between years (1986 and 1989), whereas adult females weighed less (f < 0.001) in 1986 than in 1988 or 1989 (Table 2). Adults of both sexes weighed more (f < 0.01) than their subadult counterparts. Table 2. Weights (kg) of wild turkeys trapped and radio-marked Canyon, Colorado, 1986, 1988-89. Males Females Adult Subadult Year ~ SD 1986 1988 1989 All 3.87 4.34 4.30 4.14 0.25 0.35 0.33 0.38 Recoveries in Longs ~ 3.02 3.60 3.30 3.32 Subadult Adult SD 0.46 0.26 0.29 0.45 ~ SD 7.64 0.65 7.46 7.54 0.49 0.55 ~ 5.55 SD 0.51 and Mortality Twenty-one radios, all from hens, were recovered between 1 March and 15 July 1986, and radio-contact was lost with an adult male in early May and a subadult female in mid-April. Fourteen recoveries were classified as from birds that died of natural causes, 4 were from birds that slipped their transmitters, and 3 were from birds that suffered from capture stress. Eleven of the 14 suspected natural mortalities occurred between 1 March and 10 April. Two hens died in early May prior to onset of incubation and 1 hen was killed on the nest in late May. Mortality of hens from late winter (1 Mar) through the nesting period (15 Jul) was 26%. No males died during this period. All 4 transmitters thought to have been dropped still attached to the 2 central retricies when or body parts were found near the transmitters killed, nor had the transmitters sustained any were tailmounts that were recovered. No other feathers to indicate the birds were damage (i.e., tooth marks, �82 scratches, ...etc.). It was suspected that the calamus portion of the feather was crushed when the radios were attached causing the bird to molt the damaged feathers prematurely. Three instrumented hens were recovered < 500 m from the trap site within 10 days of when they were trapped. Two had been killed (or possibly scavenged) by mammalian predators and 1 was captured alive by hand. The captured bird could not fly and fell over when attempting to run. The bird was necropsied at the Colorado State University Diagnostic Lab. It weighed 1.1 kg less (4.2 vs. 3.1 kg) than when initially captured. Gross lesions, indicative of capture myopathy (Spraker et al. 1987), were found in the thigh muscles. No lesions were found in the wing muscles. Although the 2 hens killed near the trap site appeared to be natural mortalities, they too may have suffered from capture myopathy or some other form of capture stress predisposing them to predation. Thirteen radios were recovered between 1 March and 15 July 1988, 11 from hens and 2 from males. Eleven recoveries (10 females, 1 male) were from birds that died of natural causes and 2 (1 male, 1 female) were from birds that lost their transmitters, both of which were tailmounts. Five mortalities, including the 1 male, occurred between 7 and 27 March, 2 between 1 and 17 May, and 4 between 1 and 4 June. Only 1 hen was killed on the nest. Mortality during the monitoring period was 24% for hens and 10% for males. Capture myopathy was not a mortality factor in 1988. Radios were recovered from 8 hens and 2 males in 1989. Five birds (4 females, 1 male) died of natural causes, 1 bearded hen was legally shot, 1 unbearded hen was illegally shot, and 1 male lost its tail-mounted transmitter. The remains of 2 other radio-marked hens were found together « 50 m apart) near the trap site 6 days after they were released. The primary cause of death was classified as capture stress. Two natural mortalities (including the male) occurred in late March, 1 in early April, and 2 (nesting hens) in early June. Only 11% of the radio-marked males (1/9) and females (4/35) died of natural causes between 1 March and 15 July. Nesting In 1986, 26 hens survived into the nesting season and only 5 (19%) nested successfully. Ten attempted to nest but failed, including 3 hens that abandoned their nests after being disturbed. Excluding these hens, nesting success was 22%. Two hens were killed during the laying period and 1 hen was killed on the nest. Eight hens either did not attempt to nest or lost or abandoned their clutches prior to onset of incubation. One renesting attempt was documented. Eleven (30%) of 37 hens survLvLng into the 1988 nesting season nested successfully, whereas 11 attempted to nest but failed, 4 were suspected of laying when predated, 1 was killed on the nest, and 10 either did not nest or lost their clutch during laying. Two hens that lost their transmitters during laying were not included in the sample. Only 1 hen attempted to renest. Thirty-one hens survived into the 1989 nesting season, 2 of which were shot, thus, reducing the sample to 29 hens. Only 2 (7%) nested successfully and 9 nested unsuccessfully; none attempted to renest. One hen was killed prior to incubation and 2 were killed on the nest during incubation. Fifteen hens lost their clutches during laying or did not attempt to nest. �83 Of 20 radio-marked subadult hens, 12 survived into the nesting season, but only 1 (8%) attempted to nest and did so successfully. There was no indication the others attempted to nest based on their movement patterns; i.e., they did not localize. In comparison, 50 (62%) of 80 adult hens surviving into the nesting season attempted to nest and 18 (22%) were successful. Clutch size of first nest attempts was ascertained for 7 nests in 1986 [~ 11.7 ± 1.2(SD) eggs], 8 nests in 1988 (9.3 ± 1.9 eggs), and 2 nests of 9 and 11 eggs in 1989. The smallest clutch (ll = 6 eggs) resulted from the only documented nesting attempt of a subadult. The largest clutch was 14 eggs. Clutch sizes of the 2 renesting attempts were 6 and 12 eggs. Combined clutch size of first nest attempts over the 3-year period was 10.4 ± 1.9 eggs; 134 (89%) of 151 eggs in successful nests were known to hatch. No efforts were made to collect hens or to measure nest abandonment rates of incubating females in response to human disturbances because of the small sample of hens that nested successfully each year. Instead, priority was given to documenting hatching dates and onset of incubation. Mean date for onset of incubation differed marginally (f = 0.103) among years, being later in 1989 (14 May, II = 12) than 1986 (18 May, II = 14) and 1988 (21 May, II = 22). Earliest and latest dates for initiation of incubation of first nest attempts were 6 May and 8 June, respectively. Fifty-six percent (27/48) of the hens started incubation after the spring hunting season; another 35% (17/48) started the last week of the hunting season. The peak period for onset of incubation was 16-25 May. Gobbling Adults.--Two hundred and three valid indices were obtained on 12 different males in 1986 (99 indices on 7 males) and 1989 (104 indices on 5 males). Gobbling rates did not differ between years for AM (f = 0.687) or PM (f 0.591) comparisons. Gobbling was first heard on 11 March and continued through 15 June when the gobbling indices were terminated. Radio-marked males were heard gobbling 2,830 times during 120 of 133 (90%) morning indices and 384 times during 43 of 70 (61%) evening indices. On a daily basis, gobbling was extremely sporadic. Even during peaks of gobbling under ideal conditions, there were indices when no gobbling was heard. Some males gobbled consistently more than others. The typical pattern for an adult male was to gobble more (f = 0.007) in the AM than PM, more on than off the roost for both AM (f = 0.003) and PM (f = 0.006) comparisons, more (f = 0.016) in the absence than presence of hens, and more during than before (f = 0.01) or after (f = 0.034) the hunting season (Table 3). Gobbling did not differ (f = 0.60) between preincubation and incubation periods, but occurred less frequently during postincubation than during either preincubation (f = 0.015) or incubation (f = 0.012). Two distinct peaks of gobbling were evident in 1986 (Fig. 1). The peaks were less pronounced in 1989, although the second peak in 1989 occurred at the same time as in 1986. Both second peaks of gobbling approximated the peak of incubation and occurred after the hunting season. Subadu1ts.--Eighty-five valid indices were conducted on 8 different subadult males in 1988. Subadults were first heard gobbling on 15 April and last heard on 3 June. Only 62 gobbles were recorded between 1 April and 15 June, �84 50 PEAK ONSET OF INCUBATION a:: J: <, 40 en _. w OJ OJ 30 0 (!J :E <i. 1989 ---------20 Z <t C 10 W :E o 1-10 11-20 21-30 1-10 Chronologie distribution wild turkeys. 21-30 MAY APRIL Fig. 1. Merriam's 11-20 of gobbling activity 1-10 JUNE of adult male �85 including 60 in the morning and 2 in the evening. No gobbling was recorded during 37 of 50 (74%) morning and 33 of 35 (94%) evening indices. The number of AM gobbles per index (n = 13) when subadults did gobble ranged from 1 to 27 (median = 1 gobblejhr). Subadults gobbled at a slightly higher (f = 0.076) rate on than off the roost (Table 3). Only 2 AM gobbles were heard during 16 indices when hens were absent and 58 during 34 indices when hens were present. Seventy-seven percent (46/60) of all AM gobbling occurred in the absence of adult males. Table 3. Merriam's Gobbling rate wild turkeys. (gobblesjhr) Subadults Median Category Time of day AM PM Roosting status AM on AM off PM on PM off Hensb Present Absent Timing of incubationb Preincubation Incubation Postincubation Timing of hunting Preseason Season Postseason of adult (n 12) and subadult Range (n 8) Adults Median Range 50 35 1.0 0.1 0.4-2.5 0.0-0.2 133 70 23.9 6.3 2.1- 44.8 0.0- 24.7 1,309 1,691 1,012 1,088 1.3 0.9 0.0 0.0 0.6-2.6 0.3-2.5 0.0-0.1 0.0-0.1 3,153 4,827 1,586 2,614 38.7 10.7 12.3 0.4 3.9-114.8 0.8- 29.3 0.0- 43.2 0.0- 23.8 34 16 1.3 0.0 0.4-4.0 0.0-0.7 53 46 12.0 29.2 2.8- 34.0 1.4 -56.0 27 18 0.2 2.0 0.1-5.6 0.0-2.8 C C 74 38 21 29.7 23.2 2.0 1.4- 53.7 0.7- 88.0 0.0- 30.0 0.3 0.8 1.7 0.0-0.6 0.4-4.5 0.0-3.3 38 50 45 ll.5 34.5 10.0 0.0- 52.1 2.0- 77.0 0.0- 38.6 5 seasonb 18 21 11 aTotal indices conducted except for roosting activity, which is expressed as total minutes of observation (i.e., AM min. on + AM min. off + 60 = total AM indices). bBased on AM indices only. CInadequate sample of indices per bird to compute a median and range. Subadults appeared to gobble more during incubation than preincubation (Table 3); however, because of variation in gobbling among individuals, the difference was not significant (f = 0.69). Four of 8 subadult males gobbled more during the preincubation period and 4 gobbled more during incubation. Only 5 indices were conducted during postincubation, precluding comparisons with other periods. Gobbling also appeared to increase progressively from the preseason, through the season, and into the postseason (Table 3), but again, �86 because of individual variation, no comparisons were significant (£ = 0.076, 0.222, and 0.688 for preseason vs. season, preseason vs. postseason, and season vs. postseason, respectively). Four males gobbled most during the postseason. The other 4 males did not gobble in the postseason, but instead gobbled most in the preseason (3) and season (1). Movements and Home Range Movements of 71 birds were documented from winter ranges to spring breeding areas including 11 adult and 8 subadult males, and 51 females (50 adults, 1 subadult) located on nests. Movements from the winter trap site to the area occupied in mid- to late May (nesting period) were documented for an additional 33 hens (22 adults, 11 subadults) not located on nests. Distances moved by females located on nests were similar (£ = 0.27) among years and did not differ (£ - 0.42) from distances traveled by hens not located on nests; consequently, data for females for all years were pooled. In addition. no differences (£ = 0.15) were evident in distances moved by adult males between 1986 and 1989. The data indicated that (1) subadult males moved farther (£ < 0.01) than adult males, (2) there was no difference (f = 0.91) in distances traveled by adult and subadult females, (3) adult females moved farther (f < 0.01) than adult males, and (4) subadult males and females moved similar (f = 0.61) distances (Fig. 2). Home range size locations/male) 8 subadult males were not located sizes. estimates were calculated of 11 adult males and 289 that were monitored from often enough during this from 278 locations (20-28 locations (20-31 locations/male) of 1 April through 15 June. Females time period to calculate home range The HMT spring range size of adult males averaged 5.2 ± 3.3 km2 and did not differ (f = 0.22) between years. Subadults occupied larger (12.3 ± 4.9 km2, £ < 0.01) HMT spring home ranges than adults. Minimum convex polygon home ranges for both age classes were substantially larger (f < 0.01) than HMT estimates, averaging 13.9 ± 8.2 km2 for adult males and 28.7 ± 13.8 km2 for subadult males. All 6 adult males monitored in 1986 shared a portion of their spring home range with at least 1 and up to 4 other radio-marked males. In 1989, 3 of 5 adult males shared spring home ranges, and in 1988, 7 of 8 subadults had overlapping home ranges with 1-3 other radio-marked subadults. Spring and winter home ranges overlapped for 5 of 11 adult males and 3 of 8 subadult males. Three adult males with distinct winter and spring home ranges left the winter range the first week of April; the other 3 adults and 5 subadults did not leave until the third week of April in conjunction with peak departure of hens. For those males with overlapping winter and spring home ranges, it was not clear when in April they moved onto their spring range. Roosting The median distance between morning and evening roosts used on the same day was 996 m (n = 44, range = 0-6,900 m) for subadults and 1,074 m (n = 25, range = 50-2,507 m) for adults. The median distance between roost sites located ~ 3 days apart, but not on the same day, ranged from 798-1,979 m for adult males and 859-3,389 m for subadult males. Differences (£ = 0.04) were apparent �87 25 20 (/) a: 15 W I- w _.0 ~ (72) 10 (12) (8) ~ 5 ( 11) o ADULT SUB ADULT FEMALES SUB ADULT ADULT MALES Fig. 2. Distances traveled by Merriam's wild turkeys from wintering to breeding areas. Vertical line = range, horizontal line = mean, vertical bar = standard deviation. Sample sizes are in parentheses. �88 among males within an age class. Median distances between roost sites increased during the hunting season compared to preseason (f = 0.03 for adults and subadults) and postseason (f ~ 0.03 for adults, f = 0.08 for subadults) periods, but were similar (f = 0.35 for adults, f = 0.71 for subadults) during the pre- and postseason (Table 4). Table 4. Median distance (m) between roosting sites of male Merriam's turkeys in relation to the hunting season.a Periodb n Preseason Season Postseason 39 59 53 Adult Median 1,137 1,765 1,165 Range n 50-1,371 917-2,961 800-1,597 51 50 21 Subadult Median 869 1,823 1,068 wild Range 761-2,055 925-5,162 600-2,055 aBased on roost sites located ~3 days apart but not on the same day. bpreseason -1-15 April, hunting season -16 April to 15 May, postseason -16 May to 15 June. The frequency with which adult males were found at previously-used roost sites was 19%. Subadults returned to the same roosts more often (29%) than adults, although the difference was marginal (f = 0.14). Whereas all subadult males reused at least 1 roost site, 2 adult males did not. No roost site was used more than 4 times and seldom (adults = 4%, subadults = 9%) was a roost site used on the same day; i.e., morning and evening. However, subadults (median 7 days, range = 0-24) returned to previously-occupied roosts sooner (f < 0.01) than adults (median = 12 days, range = 1-78). Departure and roosting times were recorded for males during 183 (adults = 133, subadults = 50) morning gobbling indices and 105 (adults = 70, subadults = 35) evening indices. Departure and roosting times did not differ (f = 0.35 and 0.45 for adults, f = 0.24 and 0.30 for subadults, respectively) among males within an age class. There was approximately a 20-minute period when birds went to roost or left the roost (Table 5). Extreme variations in roosting times were usually associated with overcast conditions accompanied by snow or rain. The tendency was for males to leave roosts later in relation to sunrise as spring progressed (Table 5). Adult and subadult males left the roost 11-13 minutes before sunrise during the preseason and 5-7 minutes after sunrise during the postseason. However, during the hunting season adults continued to leave the roost before sunrise, about 9 minutes earlier (f = 0.04) than subadults which departed at or just after sunrise. �89 Evening observations indicated males roosted earlier in relation to sunset as spring period progressed (Table 5). Preseason roosting times of adults and subadults occurred 6-7 minutes after sunset. During the hunting season, subadults roosted just before sunset and adults slightly after sunset. By the postseason period, adults and subadults were flying to roost before sunset. Table 5. .Spring departure <minutes before or after sunrise) and roosting (minutes before or after sunset) times of male Merriam's wild turkeys in relation to the hunting season. Subadult Adult Oe~arture Roost Perioda n E so Preseason Season Postseason 26 46 37 +10.6 + 8.2 - 5.3 10.8 8.4 8.9 n 20 26 19 E +7.2 +0.5 -7.5 Roost Oe~arture so 8.4 8.2 10.9 E n 18 20 12 +12.7 - 0.7 - 6.5 so n ~ SO 7.1 7.4 7.0 11 13 11 + 5.9 - 3.2 -13.5 8.0 9.2 5.6 apreseason -1 to 15 April, season -16 April to 15 May, postseason -16 May to 15 June. bpositive departure values indicate minutes off the roost before sunrise and negative values minutes off the roost after sunrise. CPositive roost values indicate minutes on the roost after sunset and negative values minutes on the roost before sunset. Hunter Compliance - Permit System Hunter compliance with the spring permit requirement over the 3-year period from 1986 to 1988 was 93% (Table 6). Questionnaires were sent to all permit holders by 1 June with a followup questionnaire mailed to all non-respondents 3 weeks later. The combined return rates (excluding non-deliverable surveys) for the first and second mailings were similar (-73%) among years (Table 7). Table 6. Year 1986 1987 1988 Hunter compliance Licenses 4,788 4,607 5,078 sold with permit requirement, Permits issued 4,698 4.257 4,569 spring season, 1986-88. Compliance (%) 98 92 90 There were more permits issued for the fall season than there were licenses sold. The reason was that unsuccessful spring hunters who wanted to hunt the fall season were not required to purchase another license, but were required to obtain a fall permit. Consequently, total license sales and total permits issued were not directly comparable. Hunter compliance was therefore measured as the proportion of new license buyers who also obtained a permit. The estimates were 94% (759 of 809) in 1986, 87% (776 of 892) in 1987, and 88% (782 of 889) in 1989. Questionnaires were sent to the fall permit holders by 20 October. Approximately 75% of the fall hunters responded to the questionnaire (Table 7). �90 Table 7. Response to spring and fall wild turkey harvest S:Qring 1987 1986 Surveys mailed Surveys returned Non-deliverable Percent returnb 4,698 3,365 119 73 4,257 2,999 121 73 surveys, 1986-88.a 1988 1986 Fall 1987 1988 4,569 3,267 125 74 1,819 1,328 45 75 1,751 1,253 56 74 1,599 1,163 40 75 aCombined responses for first and second mailings. bExcluding non-deliverable surveys. Hunter Activity and Harvest - Questionnaire Projected estimates for the spring season indicated an average of 3,888 hunters harvested 603 turkeys for a success rate of 16% (Table 8). Average total harvest, including a reported crippling loss of 17%, was estimated at 728 turkeys per year. Spring hunters averaged 3.5 days afield over the course of the 30-day season. About 66% fewer hunters participated in the fall season (i - 1,318 hunters) and 48% fewer birds (i = 355 turkeys) were harvested (Table 9). However, hunter success (24%) was higher and crippling loss (15%) was slightly lower. Fall hunters spent 2.7 days afield or about one day less than spring hunters, but fall hunters had only 16 days of hunting which included just 3 weekends. The spring season lasted 14 days longer, allowing for 2 additional weekends of hunting opportunity. Table 8. Spring turkey harvest Descriptive statistic N in sample N hunters % hunters N hunters observing turkeys % hunters observing turkeys a N successful hunters (harvest) % successful huntersa N hunters days Days/huntera Crippling loss % crippling loss Total harvest aBased only on those hunters and hunter activity, 1986 4,698 4,174 89 2,612 63 563 13 14,996 3.6 138 20 701 who actually hunted. 1986-88. 1987 4,257 3,670 86 2,367 64 575 16 13,215 3.6 138 19 713 1988 4,569 3,819 84 2,687 70 671 18 12,849 3.4 100 13 771 �91 Table 9. Fall turkey harvest and hunter activity, Descriptive statistic li in sample li hunters % hunters li hunters observing turkeys % hunters observing turkeys a li successful hunters (harvest) % successful huntersa li hunters days Daysfhuntera Crippling loss % crippling loss Total harvest 1986-88. 1986 1987 1988 1,819 1,414 78 768 54 313 22 3,603 2.5 47 14 360 1,751 1,314 75 715 54 278 21 3,704 2.8 60 18 338 1,599 1,225 77 677 55 355 29 3,378 2.8 60 14 415 aBased only on those hunters who actually hunted. Most hunting pressure and harvest occurred on opening weekend during both seasons (Tables 10, 11). Pressure and harvest did not change substantially over the remainder of the fall season. There was an increase in pressure on weekends during the spring season. Counties and Game Management Units in the Southeast Region accounted for over 70% of the spring and fall harvest (Tables 12, 13). Las Animas County was the leading harvest area with 23 and 30% of the spring and fall harvest, respectively. Public land supported about 54% of the spring and fall hunting pressure, but produced only 43% (spring) and 35% (fall) of the harvest (Tables 14, 15). Over 70% of the birds harvested during spring were taken before noon compared to 60% for the fall season; the primary harvest periods (Mountain Daylight Time) were 0600-0900 hours for spring and 0700-1000 hours for fall (Table 16). Hunter success on spring limited permit areas generally exceeded the statewide success rate of 16% (Table 17). It was not as advantageous in terms of success to hunt on a limited permit area during fall (Table 18). It was a definite advantage to hunt on private (spring = 26% success, fall = 43% success) vs. public land (spring = 12% success, fall = 17% success) in both seasons. Wing Collection Program Compliance.--Of the 1,440 successful spring hunters who responded to the questionnaire, 1,048 (73%) said they returned a wing. However, 1,266 wings were processed, meaning 218 successful hunters who did not respond to the questionnaire still returned a wing. The wing collection program sampled 70% of the estimated spring harvest. A total of 673 wings was collected from the fall wing survey representing 71% of the estimated fall harvest. Seventy-eight percent (579 of 739) of the successful hunters responding to the questionnaire indicated they returned a wing and 94 successful hunters not responding also returned a wing. �92 Table 10. 1986-88.a Chronological distribution of hunting pressure and harvest during the spring turkey season, 1986 Dateb Hunter da~s x !! 1987 Harvest % !! 1988 Harvest x !! Hunter da~s % .!! Harvest Hunter da~s % !! x .!! WE WK WE WK WE WK WE WK WE 3,354 1,215 1,652 650 1,201 550 884 352 619 32 12 16 6 12 5 8 3 6 1n 61 34 26 19 20 23 10 4 47 17 9 7 5 5 6 3 1 2,345 1,117 1,529 657 1,043 571 782 509 814 25 12 16 7 11 6 8 6 9 134 55 72 36 28 31 26 24 17 32 13 17 8 7 7 6 6 4 1,880 979 1,094 772 1,388 812 1,197 572 969 20 10 11 8 14 8 13 6 10 178 60 70 37 48 30 28 27 26 35 12 14 7 10 6 6 5 5 Totals 10,477 100 369 100 9,367 100 423 100 9,663 100 504 100 1st 1st 2nd 2nd 3rd 3rd 4th 4th 5th aBased on hunter days and harvest that could be assigned to specific time periods. bWE = weekend, WK = week (Mon-Fri). Table 11. 88.a Chronological distribution of hunting pressure and harvest during the fall turkey season, 1986- 1986 Dateb 1st 1st 2nd 2nd 3rd Hunter da~s % .!! 1988 1987 Harvest .!! % Hunter da~s % .!! Harvest % .!! Hunter da~s x .!! Harvest .!! x WE WK WE WK WE 1,018 398 547 285 424 38 15 20 11 16 107 35 36 24 34 45 15 15 10 15 883 459 539 284 331 35 19 22 11 13 94 30 33 22 28 45 14 16 11 14 927 400 467 322 242 39 17 20 14 10 109 42 47 36 49 38 15 17 13 17 Totals 2,672 100 236 100 2,496 100 207 100 2,358 100 283 100 aBased on hunter days and harvest that could be assigned to specific time periods. bWE = weekend, WK = week (Mon-Fri). �93 Table 12. ~ild turkey harvest by county, spring and fall 1986-88. 1986 County Las Animas Fremont Huerfano Custer Pueblo Dolores ]a MontezlJIIa Logan a Morgan ] ~ashington YlJIIa ]a Kit Carson Lincoln Mesa El Paso Larimer Baca Archuleta Teller Jefferson Boulder Bent Chaffee Otero Douglas Costi lla Park Garfield Clear Creek Delta Gilpin Adams ~eld La Plata Montrose S(2ring 1987 1988 t! x t! 93 47 38 50 31 23 12 10 13 8 106 49 43 35 31 26 25 11 10 8 7 6 17 4 15 20 5 11 5 12 13 7 7 7 4 4 6 6 3 1 3 3 2 2 2 1 1 2 2 2 1 1 1 1 6 2 1 2 2 1 1 1 1 2 Totals 397 Unknown 36 < < < < < < < < < 1 1 1 1 1 100 x 1986 Fall 1987 1988 x t! x t! x t! x 110 51 41 35 50 39 21 10 8 7 10 8 71 29 21 25 27 31 13 9 11 12 56 29 18 10 24 29 15 10 5 13 81 39 21 22 29 29 14 7 8 10 4 23 4 8 3 11 3 19 4 6 3 8 4 12 4 24 15 11 7 10 6 3 5 3 3 1 8 1 4 6 4 3 2 2 1 1 1 1 1 1 2 1 1 31 18 10 17 12 11 6 3 2 3 2 2 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 10 3 10 2 6 5 2 1 3 4 1 4 1 3 2 1 1 1 6 2 2 7 10 4 1 < 3 1 1 4 5 2 1 11 8 8 6 7 3 1 4 3 3 2 2 1 1 < 1 < 4 1 2 100 230 1 2 < < < < < < < t! 1 1 5 425 22 100 6 1 4 4 < 6 2 4 3 8 2 2 2 1 1 1 514 7 < < < < < < < < 2 4 1 2 7 1 4 < 9 aHarvest was pooled by area which included more than one county. 4 3 5 3 2 2 1 2 1 100 190 21 100 < 278 9 1 1 2 1 1 < 1 < 1 < 1 100 �94 Table 13. Wild turkey harvest by Game Management Unit (GMU), spring and fall, 1986-88. Fall Sl2ring Sering 1986 Fall 1986 !! % !! % !! x !! x 111 39 8 11 4 6 9 8 48 17 4 5 2 3 4 4 84 85 140 143 64 52 60 19 26 15 12 14 4 6 73 54 43 31 38 14 11 8 6 7 33 32 27 20 17 16 14 10 47 41 27 19 17 15 10 7 13 15 20 3 4 5 26 23 23 5 4 4 5 3 13 7 8 8 19 3 3 7 4 2 11 3 19 4 8 4 12 4 6 3 9 17 8 5 9 6 2 4 2 1 2 1 4 3 3 2 9 2 2 1 5 2 1 1 2 1 1 1 1 3 3 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 8 8 4 1 7 2 1 1 1 18 13 12 12 9 10 8 8 8 6 5 5 5 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3 2 2 2 1 1 1 1 1 1 1 4 2 1 2 1 1 22 3 8 9 2 4 2 4 1 2 4 8 1 3 3 1 1 1 1 1 1 1 1 2 6 1 4 1 514 100 X !! 84 80 68 157 37 34 25 17 16 16 11 11 11 9 8 8 6 6 6 5 3 3 3 3 2 2 2 1 1 1 1 39 9 8 6 4 4 4 3 3 3 2 2 2 1 1 1 1 < 1 Totals 405 Unknown 28 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 100 1988 GMU !! 79 1987 X CHUa 81 42 70 32 36 50 44 88 78 6 58 82 56 10 30 52 76 60 83 86 90 62 64 48 1988 1987 7 1 1 2 1 4 4 2 2 230 9 < < < < 3 1 1 1 1 2 2 1 1 100 71 711 421 96 59 103 109 107 69 581 851 86 511 58 42 20 123 144 136 78 135 130 83 771 38 118 147 140 40 77 19 51 501 56 41 142 39 145 128 46 95 99 461 57 751 146 137 141 125 52 30 l" r 2 5 5 8 8 8 5 4 4 3 1 1 5 1 1 2 1 1 1 425 22 < < < < < < < < < < < < < < < 1 1 1 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 100 7 < < < < 1 2 1 1 1 < 1 < 1 < 1 < < 1 1 < 2 1 10 2 6 2 1 3 196 15 aGame management unit numbers and boundaries were changed in 1987. bHarvest was pooled by area which included more than one game management unit. < < 1 5 1 3 1 1 2 3 4 3 3 1 2 100 278 9 100 �95 Table 14. Distribution of hunting pressure and harvest by land status, spring, 1986-88. 1986 Land status Hunters .!l. x 1988 1987 Harvest % .!l. Hunters % .!l. Harvest % .!l. Hunters % .!l. Harvest x .!l. Public Private Both 1,593 953 417 54 32 14 161 194 45 55 1,395 794 370 55 31 14 164 224 42 58 1,521 1,026 288 54 36 10 219 302 45 58 Totals 2,963 100 355 100 2,559 100 388 100 2,835 100 521 100 Table 15. Distribution of hunting pressure and harvest by land status, fall, 1986-88. 1986 Hunters .!l. x .!! Public Private Both 541 410 99 52 39 9 1,050 100 Totals Harvest - 0559 0659 0759 0859 0959 1059 1159 1259 1359 1459 1559 1659 1759 1859 1959 Harvest .!! % .!! x .!! % 54 37 9 74 134 36 64 438 327 50 54 40 6 94 183 34 66 100 208 100 815 100 277 100 % 81 146 36 64 491 336 84 227 100 911 of the wild turkey harvest SI1ring 1987 Hunters Harvest .!! 1986 0500 0600 0700 0800 0900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 Hunters % Table 16. Distribution fall seasons, 1986-88. Time pe r i.od" 1988 1987 land status spring and by time period, Fall 1987 1986 1988 N % N % N % N % N % 9 81 60 57 26 27 14 16 7 5 11 14 25 28 6 2 21 15 15 7 7 4 4 2 1 3 4 6 7 2 5 100 63 49 31 19 19 6 7 9 11 10 27 11 5 1 27 17 13 8 5 5 2 2 3 3 3 7 3 1 7 88 107 64 46 33 18 10 18 9 10 21 20 29 15 1 18 22 13 9 6 4 2 4 2 2 4 4 6 3 0 11 38 34 29 18 15 8 10 9 17 15 28 7 0 0 5 16 14 12 8 6 3 4 4 7 6 12 3 0 0 10 31 33 29 12 9 3 3 1 10 11 14 10 0 0 6 17 18 16 7 5 2 2 1 6 6 8 6 0 aMountain daylight time. 1988 N % 0 16 34 22 32 24 12 10 7 6 10 25 27 22 0 0 6 14 9 13 10 5 4 3 2 4 10 11 9 0 �96 Table 17. Hunter success on limited permit areas during spring wild turkey seasons, 1986·88. Permit area .t! Lake Dorothey Beaver Skagway Units 103 & 109 Unit 107 Unit 96 Colo. Spgs. SIIA Unit 42 75 20 40 20 50 1986 Harv 13 2 16 9 17 Succ (%) .t! 1987 Harv Succ .t! 1988 Harv Succ 17 10 40 45 36 75 20 40 20 70 5 16 4 11 1 23 0 21 20 27 5 33 0 75 30 40 20 70 5 10 13 3 15 6 22 1 6 17 10 37 30 31 20 60 aNl.Illber permi ts iSSUed. Table 18. Hunter success on limited permit areas during fall wild turkey seasons, 1986-88. Permit area Lake Dorothey Beaver Skagway Units 103 & 109 Unit 96 Spanish Peaks .t! 1986 Harv Succ (%) .t! 1987 Harv Succ .t! 1988 Harv Succ 65 30 20 20 81 8 8 12 7 23 12 27 60 35 28 75 30 25 15 4 8 20 13 32 75 30 25 7 7 8 9 23 32 90 11 12 90 5 6 aNt.mberpermi ts iSSUed. Subspecies Composition.--The Merriam's wild turkey was the dominant subspecies identified from inspection of wings. It comprised 91 and 96% of the spring (Table 19) and fall (Table 20) samples, respectively, and was harvested in 29 of the state's 63 counties. Rio Grande's were taken in 10 counties: Fremont, EI Paso, Pueblo, Logan, Washington, Morgan, Yuma, Kit Carson, Lincoln, and Weld. Both subspecies were harvested in Fremont, EI Paso, and Pueblo counties. Age and Sex Composition.--Seventy-three percent of the spring harvest (males only) of Merriam's wild turkeys were adults compared to 50% for Rio Grande's (Table 19). Twenty-two (2%) wings examined from the spring sample were from females. All were Merriam's, most (91%) were adults, and all were assumed to be from legally harvested hens (i.e., bearded hens). However, the 2 subadults may have been illegally harvested as subadu1t hens seldom have visible beards. Females (Merriam's only) comprised 32 (excluding juveniles) and 53% (including juveniles) of the fall sample (Table 20). Samples « 20 wings/year) of Rio Grande wings were inadequate for meaningful interpretation. Sex ratios of fall-harvested adults favored females (1.4:1), whereas the sex ratio of juveniles favored males (1.3:1). Sex ratios of subadults, which were poorly represented (4%) in the fall harvest, were strongly skewed (13.5:1) towards females. Production, based on percent juveniles in the harvest (48%) and the ratio of juveniles to adult and subadult females (1.5:1), was only fair (1986 and 1987) to poor (1988). �97 Table 19. Sex, age, and subspecies composition harvest based on wing analyses, 1986-88. Females Adult Subadult % % N N Males Subadult % N Subspeciesa Year 1986 1987 1988 1986-88 Adult % N of the spring wild turkey M RG M & RG 80 20 100 23 57 26 264 15 279 76 43 73 0 0 0 M RG M & RG 60 14 74 18 41 20 269 20 289 79 59 77 2 0 2 M RG M & RG 147 24 171 33 50 34 294 24 318 66 50 65 0 0 0 M RG M & RG 287 58 345 25 50 27 827 59 886 73 50 71 2 0 2 1 1 < 1 < 1 5 0 5 1 8 0 8 2 7 0 7 1 20 0 20 2 Total 349 35 384 1 339 34 373 2 448 48 496 1 1,136b 117 1,253 2 aM = Merriam's, RG = Rio Grande. bThirteen (1986 = 6, 1987 = 4, 1988 = 3) additional Merriam's wings were processed but could not be classified to age or sex, bringing the total wings to 1,149. Table 20. 1986-88.a Age and sex composition of the fall harvest of Merriam's wild turkey based on wing analyses, Adults Females Males Year 1986 1987 1988 1986-88 .!i % .!i 38 32 56 126 42 41 42 42 52 46 76 174 % Totals .!i Males % .!i 58 90 40 59 78 45 58 132 57 58 300 48 2 0 0 2 Subadults Females .!i % 18 6 0 7 0 9 7 25 82 100 100 93 % Totals !i. % 11 7 9 27 aExcludes Rio Grande's due to small sample sizes (1986 5 4 4 4 = Juveniles Males Females % !i. % !i. 75 40 52 167 7, 1987 61 46 58 56 = 47 47 37 131 39 54 42 44 8, 1989 = Totals Sample % size .!i 122 87 89 298 19). 55 51 (39) (48) 223 172 230 625 Poults/ hen 2.0 1.6 1.0 1.5 �98 DISCUSSION Nesting The average clutch size for Merriam's wild turkeys in Colorado was similar to average clutch sizes of 9.3, 10.9, and 9.9 eggs reported from New Mexico (Lockwood and Sutcliffe 1985), Oregon (Lutz and Crawford 1987E), and Washington (Mackey 1982), respectively. None of the unsuccessful hens in the Oregon study attempted to renest. The renesting rate in New Mexico was 29%, with only adult hens attempting to renest. Estimates of hatching success ranged from 87% in New Mexico to 96% in Washington. Yearling Merriam's wild turkeys apparently have a lower propensity to nest than adults. For example, 75% of the adults and only 8% of the yearling hens monitored in New Mexico attempted to nest (Lockwood and Sutcliffe 1985). Nesting rates of yearling hens in South Dakota (Wertz and Flake 1988) and Oregon (Lutz and Crawford 1987E) were 0 and 25%, respectively, compared to 42 (South Dakota) and 75% (Oregon) for adults. The nesting rates in this study were 8% for yearlings and 62% for adults. However, hens classified as nonnesters (especially adults) may have attempted to nest, but lost their clutches during laying. The frequency of non-breeding by yearlings, and possibly some adults, merits further study. Average nesting success of adults in this study was lower than the 37% success reported by Lockwood and Sutcliffe (1985) in New Mexico and the 75% success reported for an introduced population in Oregon (Lutz and Crawford 1987E). In addition, nesting rates (97%), renest attempts (23%), percent yearlings nesting (95%), and nesting success (58%) were all higher in an expanding Rio Grande population in northeast Colorado (Schmutz and Braun 1989) than in the Merriam's population studied in southcentra1 Colorado. These data lend support to the hypothesis that reproductive performance in stabilized turkey populations is lower than that in expanding populations (Vangilder et al. 1987, Porter 1978). No density estimates were available to ascertain whether the Merriam's population studied was being maintained at such low reproductive rates. High density (20-30 birds/km2 of timber) populations were maintained in Missouri when nest success averaged 35-40% (Vangilder et al 1987) and annual hen survival rates averaged 44% (Kurzejeski et al. 1987). Lockwood and Sutcliffe (1985) estimated the median incubation date for Merriam's wild turkeys in southeastern New Mexico to be 20 May. In central Arizona, Scott and Boeker (1972) reported the peak of hatch occurred around 15 June; backdating 28 days places the peak of incubation around 19 May. Nest initiation dates in South Dakota ranged from 20 April to 13 June (Wertz and Flake 1988). The corresponding incubation dates were 15 May and 8 July. No distinction was made between first and second nest attempts. Hatching dates for 15 nests in Oregon occurred over an 8-day period from 28 May to 4 June (Lutz and Crawford 1987E). Incubation dates for these nests ranged from 2 to 8 May and were similar to dates reported by Mackey (1982) in Washington. Unpublished data from northern Arizona (H. G. Shaw, Ariz. Game and Fish Dep.) and southeastern Montana (J. E. Gobielle, Mont. State Univ.) indicated most hens started incubation in early May and late May, respectively. The Montana data may have included second nest attempts. Jonas (1966), in contradiction to Gobielle's data, reported incubation in southeastern Montana started in �99 late April-early May. Jonas (1966) derived incubation dates indirectly from hatching dates assigned to poults visually classified to age in the field or from harvest samples of poults that were classified to age based on primary measurement techniques developed for eastern wild turkeys (M. g. silvestris) (Knoder 1959). This approach produced an inflated estimate of age and consequently an earlier estimate for onset of incubation. The peak of incubation (16-25 May) in southcentral Colorado approximated (± 2 weeks) dates reported from elsewhere within the native and expanded range of the Merriam's wild turkey. This relative uniformity among states suggests that photo-period ultimately controls nesting. Photoperiod best explained the synchrony of turkey nesting in Vermont (Wallin 1983). Spring weather had a secondary influence on timing of nesting as evidenced by earlier nesting in 1989 compared with 1986 and 1988. Vangilder et al. (1987) attributed annual variations in nesting chronology to spring temperatures. However, there appears to be a period, regardless of weather, before which hens will not initiate nesting. In this study and a study in southeastern New Mexico (Lockwood and Sutcliffe 1985), no hens started incubation before 6 May despite annual differences in spring weather conditions. Late April appears to be the earliest Merriam's wild turkeys initiate incubation. The median date for onset of incubation by Rio Grande wild turkeys in northeastern Colorado in 1986 was 6 May (Schmutz and Braun 1989). The median date of incubation for Merriam's turkeys in southcentral Colorado in 1986 was 18 May, almost 2 weeks later. Rio Grande's were incubating as early as 21 April. Phenological differences between study areas were at least partially responsible for advanced nesting in northeastern Colorado, but behavioral or physiological differences between subspecies also may have contributed to earlier nesting by Rio Grande's. Gobbling In Minnesota, the primary peak of gobbling associated with mating was consistent among years and occurred during the third and fourth weeks of April (Porter and Ludwig 1980). A secondary peak of shorter duration occurred in mid-May. Gobbling was heard throughout the monitoring period from 1 April to 17 June. Bevill (1975) documented a similar pattern of gobbling activity in South Carolina, except the primary (mid-Apr) and secondary (late Apr) peaks were earlier. Dates when gobbling was first and last heard ranged from 1 March to 10 July (Bevill 1973). Gobbling activity in Alabama peaked during the first and last weeks of April and ceased by mid-June (Davis 1969). The chronology of gobbling activities in Colorado most closely resembled patterns reported in Minnesota. Methods used to monitor and quantify gobbling have differed among studies, making comparisons difficult. Bevill (1973, 1975) recorded AM gobbling from fixed stations. He monitored both general and individual gobbling behaviors. Most other studies (Donohoe and Martinson 1963, Scott and Boeker 1972, Porter and Ludwig 1980) focused on general gobbling behavior and generated data from morning call-count routes. Davis (1969) used a combination of call-count routes and fixed stations to study general gobbling behavior. In this study, AM and PM gobbling indices were conducted on individuals, with location of the index depending upon where the bird roosted. �100 Wide daily variations in gobbling activity were apparent in all studies. When individuals were studied, it was apparent some males called more prolifically than others. Weather conditions accounted for some of this variation (Davis 1969, Bevill 1973), as did progression of the breeding season and, especially, onset of incubation. Gobbling increased on the roost and in the absence of hens. None of the cited studies specifically assessed gobbling in the presence or absence of hens. If gobbling serves to attract females (Bailey 1967:105), it should intensify in the absence of hens, which it did. Males also gobbled in the presence of hens and did not always gobble in their absence, suggesting gobbling may function in ways besides attracting females. Gobbling was most consistently heard during the morning when males were still on the roost. Bevill (1975) recorded his highest counts during the 20 minutes preceding sunrise. In 89 days of monitoring, he heard ~ 1 gobble on 53 (60%) mornings between 10 and 20 minutes before sunrise. I heard gobbling 73% of the time during the same interval. Bevill's (1973) study further indicated that adult eastern wild turkeys gobbled more than subadults. Converting his data to gobblesfhour revealed that adults gobbled an average of 62 timesfhour and subadults 13 timesfhour. Both age classes of eastern wild turkeys gobbled more than their respective age class of Merriam's. Bevill's (1973, 1975) data were collected from an unhunted population and may not reflect the true gobbling characteristics of eastern wild turkeys. He reported sporadic gobbling patterns for all stations on hunted areas. He excluded these data from the analyses. Davis (1969) also had difficulty interpreting gobbling data collected on hunted areas. His comparisons were complicated by use of different methods of monitoring gobbling on hunted (fixed stations) and unhunted (call-count routes) areas. Although questionable, evidence from his study indicated that gobbling was more sporadic and occurred less frequently on hunted areas. This may be a normal response to hunting pressure. Males monitored in southcentral Colorado were subjected to low hunting pressure and may have gobbled more than males on more heavily hunted areas. Mortality Neither the illegal harvest of non-bearded hens nor the legal harvest of bearded hens were major causes of mortality. Furthermore, only 2 radio-marked hens were reported harvested during the fall either sex season. Poaching accounted for almost 39% of the losses of radio-marked hens in Missouri; 42% of the total losses attributed to poaching occurred as a result of illegal harvest during the spring gobbler season (Kurzejeski et al. 1987). The legal fall harvest accounted for only 3% of the hen mortality. Spring hunting pressure in Missouri greatly exceeds that in Colorado. This factor alone was probably responsible for the high hen losses in Missouri due to illegal harvest. Mortality from late winter (Mar) through the nesting period (mid-Jul) was greater for hens than males. No males were harvested during the year they were being monitored and only 2 were shot in subsequent years. No gobblers were killed by predators during the breeding season (1 Apr-IS Jun). Most hen mortalities occurred prior to the onset of incubation. Nest losses were high, but mortality of hens on the nest was low. Although seasonal losses of hens in Missouri were highest (23%) during spring (14 Mar-31 May), few hens were �101 actually killed while incubating eggs (Kurzejeski et a1. 1987). In contrast, Speake (1980) identified incubation and the first 2 weeks of brood rearing as the time when hens were most vulnerable to predation. Home Range and Movements Although both HMT and MCP estimates indicated male Merriam's wild turkeys occupied large spring home ranges, MCP estimates exceeded HMT estimates by > 100%. MCP home ranges of Merriam's wild turkeys in Oregon (Lutz and Crawford 1989) were also larger than HMT home ranges reported here, averaging 1,655 ha for adult males and 2,345 ha for subadult males. Conversely, MCP home ranges (~ = 150 ha) of subadu1t males in Washington (Mackey 1982) were much smaller. Both investigators studied introduced populations and relied on triangulation techniques. Furthermore, Mackey (1982) collected home range data incidental to other objectives and, as a consequence, had additional sampling biases associated with his data set that were not apparent in the other studies. Brown (1980) found similar, but less extreme disparities in published home range sizes for eastern wild turkeys which he partly explained by differences in sampling and analyses from one study to another. The MCP home ranges included all location points between 1 April and 15 June. The HMT method, using the 90% contour interval, eliminated outlier locations and, thus, excluded some areas that were part of the MCP ranges. There was behavioral evidence that supported using the HMT approach, and suggested the MCP approach included (1) areas that were seldom used, and (2) portions of the winter and transitional ranges that were not part of the spring range. For example, all males used portions of their range more intensively than others. In addition, few males moved directly from winter to spring ranges, but instead, left the winter range over a period of about 3 weeks and used transitional ranges in the interim before moving onto spring ranges. Finally, some males used portions of their winter range throughout the spring period, whereas others had distinct winter and spring ranges. Subadu1ts occupied larger spring home ranges and used more areas within their ranges than adults. This was consistent with findings of Lutz and Crawford (1989), but in contradiction to published findings for eastern wild turkeys (Fleming and Webb 1974). Subadults frequently localized in certain areas within their range, sometimes for as long as 2 weeks, but seldom returned to these areas once they left. In comparison, adults repeatedly used several different areas within their spring ranges. Occasionally, they ventured away from normal areas of activity, but usually returned in < 1 week. These intense use areas varied from < 0.5 to almost 6 km apart. Wigley et a1. (1986) also found widely separated areas of intense activity within home ranges of eastern wild turkeys in Arkansas. Poor quality habitat has been cited as an explanation for large annual home ranges occupied by eastern wild turkeys in Arkansas (Wigley et a1. 1986) and Merriam's wild turkeys in Oregon (Lutz and Crawford 1989). Spring ranges of males, however, may be influenced by other factors in addition to habitat quality. Porter (1977) noted that during the breeding season males moved more and with less predictability than females. He contended the male's reproductive drive was the primary factor controlling spring movements. The period of increased movements of males, as indicated by distances between roosting sites, occurred from mid-April to early May and coincided with when �102 hens were moving to nesting areas. This increase in mobility of males occurred in conjunction with the spring hunting season. However, hunting pressure was minimal and not considered a factor influencing movements. Based on chronology of nesting events, mid-April to early May was also the period when hens were most receptive to males. Since males did not associate with the same hens throughout the breeding season, they had to periodically search for receptive hens. Males were more sedentary both before and after the hunting season when hens were still in flocks on winter range or localized on nesting areas. These observations partially agree with Porter's (1977) contention and suggest that size of a male's spring range was at least partially dependent upon availability of hens. Home range characteristics for wild turkeys differ greatly across their geographic range. Even within the range of individual subspecies, home range sizes vary markedly. Expansion into non-historic habitats has added to this variation and confounded development of management strategies precise enough to be meaningful, but general enough to apply to the range of environments occupied by wild turkeys. This especially applies to the concept of home range because it is rarely defined the same way and is affected by a number of other factors. Brown (1980) recommended that instead of developing management plans based on home range data obtained from several studies conducted over a wide area, it may be more appropriate to develop separate plans, each specific to the region where the data were collected. Brown's (1980) recommendation may be excessive and suggests emphasis should be placed on standardizing sampling methods and data analysis. Care must also be taken to define the time frame over which the home range estimate represents and what areas are included within the home range. For example, spring as defined included the period when some males were in transition between winter and spring ranges, while other males were still on winter range. This had a pronounced influence on home range estimates and, had it not been identified, values representing size of spring home ranges would have been misleading. Home range estimates revealed little about spring movements of males but, in combination with data on spatial relationships of roosting sites, indicated that males moved extensively during spring. Scott and Boeker (1972) did not fully understand the extent of spring movements and inconsistent gobbling patterns of Merriam's wild turkeys when they proposed that gobbling surveys could be used as a population index for this subspecies. Even with the tight control of extrinsic variations that was accomplished by Porter and Ludwig (1980), use of gobbling surveys to monitor relative abundance and trends in population growth of Merriam's wild turkeys is questionable without further research. Roosting Male Merriam's wild turkeys demonstrated low fidelity to spring roosting sites. This was not surprising considering the size of their spring home ranges. Even adults, which repeatedly used the same areas within their spring ranges, did not select the same roosting sites within these areas. In Oregon, Lutz and Crawford (1987h) identified few traditionally-used roost sites during any season. They did not quantify fidelity, but reported all spring roosting sites were only lightly used. I implied this to mean at least some sites were used more than once. In New Mexico, hen turkeys used only I of 29 summer �103 roosts more than once (Schemnitz et al. 1985). roosts were repeatedly used. In the same study, 29 winter Rio Grande wild turkeys in Oklahoma consistently left the roost about 15-20 minutes before sunrise throughout spring (Logan 1973). Roosting times ranged from sunset to 30 minutes after sunset, becoming later as spring progressed into summer. Early spring (analogous to the preseason period) departure times of Merriam's wild turkeys monitored in a previous Colorado study (Hoffman 1968) ranged from 10 to 15 minutes before sunrise; roosting times were more variable, ranging from 3 minutes before to 19 minutes after sunset. I observed a wider range of departure times than reported by Logan (1973) or Hoffman (1968), but a comparably broad range of roosting times. Hens were often present or nearby when I was monitoring roosting behavior. When this occurred, males departed and roosted concurrently with hens. In the absence of hens, adult males remained on the roost longer in the morning, but did not alter evening roosting patterns. Harvest Survey The permit system allowed quick access to names and addresses of hunters so the survey could be conducted immediately following each season. The other option was having to wait for the license agents to return license stubs containing hunter's names and addresses. Although agents have deadlines for returning license stubs, they do not always comply. In some cases, license stubs for the spring season are not received until August. In 1984, an attempt was made to survey spring hunters from names on license stubs. Because of the time required to obtain all the license stubs from the agents, the first mailing was delayed until 23 July. By bypassing the license agents and issuing permits at CDOW offices, the first mailing of the 1986 spring survey was out by 1 June, just 2 weeks after the season closed. Prior to 1984, the CDOW conducted 1 turkey harvest survey annually. Surveys were mailed in November and sampled about 50% of the license buyers with no attempt to stratify by spring only, fall only, or spring and fall hunters. In addition, not all license agents had returned license stubs when the sample was taken. Incomplete addresses recorded on the licenses plus the time lag between when the license was issued and when the survey was mailed resulted in a high percentage of non-deliverable surveys; i.e., 6-10% using license stubs vs. 2% using permits. Surprisingly, response rates did not differ between surveys conducted using names taken from license stubs or from permits. In 1989, the CDOW went to a separate license for spring and fall, thus, eliminating some problems with the old license system. Hunting pressure and harvest of wild turkeys in Colorado increased nearly 400% between 1973 and 1983 (Colo. Div. Wildl. 1984). The primary increases occurred in spring hunting pressure (600%) and spring harvest (1,000%). The harvest survey conducted between 1986 and 1988 suggested that hunting pressure and harvest had stabilized. However, as huntable turkey populations become reestablished on the West Slope, another increase in hunting pressure and harvest is anticipated. These populations have the potential to offer more hunting opportunity than East Slope populations, because they frequently occur on public lands readily accessible to the hunters. �104 Wing Collections The validity of any population index calculated from harvest samples is dependent upon the assumption that different age and sex classes are harvested in proportion to their occurrence in the population. Long-term population and harvest data are often necessary to test this assumption. Such data are not available for the Merriam's wild turkey in Colorado or elsewhere throughout its range. In addition, if wings are collected over a broad geographic area, they may not accurately reflect characteristics of local populations. These limitations do not preclude the use of wing data as a tool in formulating management strategies. Biologists must be aware of them and use caution in interpreting the data. Examination of wings (Merriam's only) originating from the fall season revealed the sex ratio of adults and subadults combined favored females, while the sex ratio of juveniles favored males. The biological implications of these ratios are difficult to interpret without knowledge of the population structure. Hoffman (1962) reported winter counts of 1.6 females:l male along the Front Range in southeastern Colorado. The sex ratio of 171 turkeys harvested on the Uncompahgre Plateau during the fall 1961 and 1963-67 was 1.7 females:l male (Myers 1973). Both ratios are based on combined samples of adults, subadults, and juveniles. A comparable ratio using the 1986-88 data would be 1.1 females:l male. Myers' data examined by age class indicates the sex ratio of adults and subadults (2.5:1) and juveniles alone (1.5:1) still favored females. Subadults were poorly represented in the fall harvest samples in all years. Biologically, this could be interpreted as poor production and subsequent low recruitment. However, another factor contributing to the low number of subadults is associated with the onset of primary molt and whether key feathers (primaries IX and X) for separating adults and subadults are still present at the time wings are collected. If these feathers have already molted, subadu1ts cannot be distinguished from adults. This was the case as 100% of the males and 51% of the females had completed their primary molt by the fall season. The problem of separating adults and subadults was compounded for males because they start and finish their primary molt before females. Misidentification of subadults is not a problem in spring when the birds are just beginning to molt their primary feathers. LITERATURE Amstrup, S. C. 44:214-217. 1980. A radio-collar CITED for game birds. J. Wildl. Manage. Bailey, R. W. 1967. Behavior. Pages 92-112 in O. H. Hewitt, ed. turkey and its management. The Wildl. Soc., Washington, D.C. _____ , and K. T. Rinell. 1967. Events in the turkey year. Pages H. Hewitt, ed. The wild turkey and its management. The Wildl. Washington, D.C. Bevill, W. V., Jr. turkeys. Proc. The wild 73-91 Soc., 1973. Some factors influencing gobbling activity Southeast. Assoc. Game and Fish Comm. 27:62-73. in O. among �105 1975. Setting spring gobbler hunting Proc. Nat1. Wild Turkey Symp. 3:198-204. Bray, O. E., and G. W. Corner. to birds. J. Wildl. Manage. seasons by timing peak 1972. A tail clip for attaching 36:640-642. Brown, E. C. 1980. Home range and movements Proc. Natl. Wit~ Turkey Symp. 4:251-261. of wild Burget, M. L. 1957. The wild turkey in Colorado. Dep. Fed. Aid Proj. W-39-R. 68pp. turkeys Colorado gobbling. transmitters - a review. Game and Fish Colorado Division of Wildlife. 1984. Colorado small game, furbearer varmint harvest. Dep. Nat. Resour., Div. Wildl., Denver. 210pp. Davis, J. R. survival. 52pp. and 1969. Wild turkey investigations - breeding, nesting and brood Job Completion Rep. Alabama Fed. Aid Proj. W-35-R, Job II-E. Dixon, K. R., and J. A. Chapman. 1980. Harmonic activity areas. Ecology 61:1040-1044. mean measure of animal Donohoe, R. W., and R. K. Martinson. 1963. Wild turkey inventory, Pages 43-45 in K. W. Laub, ed. Game research in Ohio. Vol. 2. Nat. Resour., Div. Wildl., Columbus. 1958-61. Ohio Dep. Fleming, W. H., and L. G. Webb. 1974. Home range, dispersal, and habitat utilization of wild turkey gobblers during the breeding season. Proc. Southeast. Assoc. Game and Fish Comm. 28:623-632. Hoffman, D. M. 1962. The wild turkey in eastern Game and Fish Tech. Publ. 12. 49pp. Colorado. Colorado Dep. 1966. Merriam's turkey roost preferences on mountain Colorado Div. Wild1. Game Info. Leafl. 45. 6pp. ranges. 1968. Roosting sites and habits Wildl. Manage. 32:859-866. in Colorado. of Merriam's turkeys J. 1973. Some effects of weather and timber management on Merriam's turkey in Colorado. Pages 263-271 in G. C. Sanderson and H. C. Schultz, eds. Wild turkey management: current problems and programs. Univ. Missouri Press, Columbia. Jonas, R. J. 1966. Merriam's turkeys in southeastern and Game Dep. Tech. Bull. 3. 36pp. Knoder, E. 1959. rate of primary 1:159-176. Montana. Montana Fish An aging technique for juvenal wild turkeys based on the feather moult and growth. Proc. Natl. Wild Turkey Symp. Kurzejeski, E. W., L. D. Vangilder, and J. B. Lewis. 1987. turkey hens in Missouri. J. Wildl. Manage. 51:188-193. Survival of wild �106 Lockwood, D. R., and D. H. Sutcliffe. 1985. Distribution [sic] mortality, and reproduction of Merriam's turkey in New Mexico. Proc. Natl. Wild Turkey Symp. 5:309-316. Logan, T. H. Oklahoma. 1973. Proc. Seasonal behavior of Rio Grande wild turkeys in western Southeast. Assoc. Game and Fish Comm. 26:74-91. Lutz, R. S., and J. A. Crawford. 1987~. Reproductive success and nesting habitat of Merriam's wild turkeys in Oregon. J. Wi1dl. Manage. 51:783787. _____ , and and hen-poult _____ , and Merriam's 1987Q. Seasonal flocks in Oregon. wild 1989. turkey use of roost sites by Merriam's Northwest Sci. 61:174-178. Habitat use and selection and home ranges in Oregon. Great Basin Nat. 49:252-258. Mackey, D. L. 1982. Ecology of Merriam's wild Washington with special reference to habitat Washington State Univ., Pullman. 87pp. Mohr, C. O. mammals. 1947. Table of equivalent Am. Midl. Nat. 37:223-249. 1977. Home range J. Wildl. Manage. of turkey in southcentral utilization. M.S. Thesis, populations of North American Myers, G. T. 1973. The wild turkey on the Uncompahgre Plateau. Colorado Div. Wildl. Fed. Aid. Proj. W-37-R. l53pp. Porter, W. F. Minnesota. turkey hen dynamics of wild 41:434-437. turkeys small Final Rep. in southeastern _____ 1978. The ecology and behavior of the wild turkey (Meleagris gallopavo) in southeastern Minnesota. Ph.D. Thesis, Univ. Minnesota, Paul. l22pp. St. _____ , and J. R. Ludwig. 1980. Use of gobbling counts to monitor the distribution and abundance of wild turkeys. Proc. Natl. Wild Turkey 4:61-68. Symp. Schemnitz, S. D., D. L. Goerndt, and K. H. Jones. management of Merriam's turkey in southcentral Wild Turkey Symp. 5:199-231. 1985. Habitat needs and New Mexico. Proc. Nat1. Schmutz, J. A., and C. E. Braun. 1989. Reproductive Grande wild turkeys. Condor 91:675-680. performance Scott, V. E., and E. L. Boeker. 1972. An evaluation Arizona. J. Wildl. Manage. 36:628-630. of turkey Speake, D. W. 1980. Predation Turkey Symp. 4:86-101. on wild turkeys in Alabama. of Rio call counts in Proc. Natl. Wild Spraker, T. R., W. J. Adrian, and W. R. Lance. 1987. Capture myopathy in wild turkeys (Meleagris gallopavo) following trapping, handling, and transportation in Colorado. J. Wildl. Dis. 23:447-453. �107 Stuwe, M., and C. E. B10whowiak. analysis of animal locations. Smithsonian Inst., Washington, 1986. Micro computer program for the Conserv. and Res. Cent., Natl. Zool. Park, D.C. 18 pp. Vangilder, L. D., E. W. Kurzejeski, V. L. Kimmel-Truitt, and J. B. Lewis. 1987. Reproductive parameters of wild turkey hens in north Missouri. Wildl. Manage. 51:535-540. Wallin, J. A. 1983. Eastern wild turkey tolerance to human disturbance during incubation and its relationship to spring hunting in Vermont. Thesis, Univ. Vermont, Burlington. 43pp. Wertz, T. L., and L. D. Flake. 1988. Wild turkey nesting central South Dakota. Prairie Nat. 20:29-37. ecology J. M.S. in south Wigley, T. B., J. M. Sweeney, M. E. Garner, and M. A. Melchiors. 1986. Wild turkey home ranges in the Ouachita Mountains. J. Wildl. Manage. 50:540544. Prepared by ��109 FINAL REPORT State of: Colorado Project: W-152-R Upland Work Plan: 13 Job Title: Seasonal Habitat County. Colorado Period Covered: Author: Personnel: Anthony Bird Research Job _9_ 01 January Use by Plains through Sharp-tailed 31 December Grouse in Dou~las 1989 W. Hoag C. E. Braun, K. Demarest, D. Prenzlow, Colorado Division of Wildlife; A. W. Hoag, E. Redente, Colorado State University ABSTRACT The status and habitat use by plains sharp-tailed grouse (Tympanuchus phasianel1us jamesii) were investigated during 1986-88 in Douglas County, Colorado. This subspecies once occupied suitable habitats in northeastern Colorado, but its range has been greatly reduced because former habitats have been altered by man. Within Colorado, the estimated population size in 198688 was 175-225 birds existing only in Douglas County in an area with 6 known leks and 2 historic lek sites. Habitat use was studied by following 23 grouse captured on 4 leks that were fitted with solar-powered radios. Seven habitat variables and 7 sharp-tailed grouse activities were studied. Canopy cover, plant height, and distance to clump cover were most important in identifying areas used by grouse. Habitat use varied by season and sex. Shrub communities dominated by Gambel oak (Quercus iambelii) and true mountainmahogany (Cercocarpus montanus) were selected in fall and winter and for escape and nesting. Transition zones between shrub-do~inat~d areas and grasslands were selected in spring and for roosting and nesting. Grasslands ~ere selected in summer and for feedingloafing and mating activities. Home range size varied between 103 and 363 ha for males and 306 and 884 ha for females. Management of private lands inhabited by plains sharp-tailed grouse should focus on maintaining residual vegetation from the previous year to increase cover for nesting, brooding, feeding-loafing, and roosting with a goal of maintaining a minimum of 6 occupied lek sites with documented interchange among sites. A population monitoring system should be established to document number of active leks and birds attending each on an annual basis. ��111 THESIS PLAINS SHARP-TAILED GROUSE USE IN DOUGLAS STATUS AND HABITAT COUNTY, COLORADO Submi tted by Anthony Department In partial W. Hoag of Range fulfillment for the Degree Colorado Science of the requirements of Master of Science State University Fort Collins, Colorado Fall 1989 �112 COLORADO STATE UNIVERSITY November 6, 1989 WE HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER OUR SUPERVISION BY ANTHONY W. HOAG ENTITLED PLAINS SHARP-TAILED GROUSE STATUS AND HABITAT USE IN DOUGL~S COUNTY, COLORADO BE ACCEPTED AS FULFILLI~G IN PART REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE. Committee AdViS~/ on Graduate . @J/ epar;ment Head ii Work �113 ABSTRACT PLAINS SHARP-TAILED OF THESIS GROUSE USE IN DOUGLAS The status and habitat (Tvrnpanuchus phasianellus Douglas County, habitats reduced because Colorado, Colorado. historic lek sites. Habitat that were grouse and distance dominated mountainmahogany and for escape areas nesting. mating males Habitat Grasslands activities. radios. were oak Transition 6 known Canopy Within were selected zones between on 4 leks variables plant Shrub and true in fall and winter shrub-dominated were selected in spring and for roosting were selected in summer and for feeding-loafing Home range size varied and 306 and 884 ha for females. iii between and in identifying and sex. gambelii) birds leks and 2 cover, important by season (Quercus montanus) greatly 175-225 Seven habitat studied. use varied by Gambel by man. was in suitable 23 grouse captured cover were most (Cercocarpus and grasslands altered 1986-88 during its range has been in an area with activities grouse once occupied size in 1986-88 solar-powered and nesting. but by following to clump areas used by grouse. communities County use was studied fitted with sharp-tailed investigated have been population in Douglas 7 sharp-tailed height, Colorado, the estimated only were COLORADO This subspecies former habitats existing COUNTY, use by plains jamesii) in northeastern STATUS AND HABITAT and 103 and 363 ha for and �114 Management should focus to increase with of private on maintaining cover should interchange be established attending inhabited residual for nesting, a goal of maintaining documented lands vegetation brooding, a minimum among sites. to document by plains from the previous feeding-loafing, of 6 occupied A population number sharp-tailed of active grouse year and roosting lek sites with monitoring system leks and birds each on an annual basis. Anthony W. Hoag Department of Range Science Colorado State University Fort Collins, CO 80523 Fall 1989 iv �115 ACKNOWLEDGMENTS This study was supported thank Drs. Ed F. Redente in providing support employees of Wildlife. as I pursued along with their demand my degree. of the Colorado and useful suggestions Division comments. of Wildlife Without to I also thank for their frank Dr. Wayne C. Leininger on the thesis. I efforts for commitment I would not have learned as much as I did. discussions helpful Division and Clait E. Braun for their tireless and direction their open door policy excellence, by the Colorado provided I thank Diane K. Hall for preparing the final copy of the thesis. I am deeply Science indebted and Fishery thank Andy Sipowicz. were invaluable. conduct research to my fellow graduate and Wildlife Biology His critical Tweet Kimball Departments. comments during and Dave Miller on their ranches. students in the Range In particular, I thesis preparation graciously I hope their interest allowed me to in sharp- tailed grouse remains high. Lastly, continued I could not have completed support. I thank my mother degree as enough and for encouraging this project without for not accepting my undergraduate me to finish my masters v my family's degree. �116 Table of Contents ABSTRACT OF THESIS iii ACKNOWLEDGMENTS. LIST OF TABLES . viii LIST OF FIGURES. Chapter 1. ix DISTRIBUTION AND ABUNDANCE OF PLAINS SHARP-TAILED GROUSE IN DOUGLAS AND ELBERT COUNTIES, COLORADO. Introduction. 1 Study Area. 2 Methods Results ') Discussion. Literature Chapter 2. 6 Cited. SEASONAL HABITAT USE BY PLAINS SHARP-TAILED DOUGLAS COUNTY, COLORADO GROUSE IN Introduction. 8 Study Area. 9 Methods 11 Results 14 14 Trapping Movements Habitat Discussion. Literature 14 and Home Range Characteristics. 16 30 . . . 38 Cited. vi �117 Table of Contents Chapter 3. (Continued) MANAGEMENT RECOMMENDATIONS FOR MAINTENANCE OF PLAINS SHARP-TAILED GROUSE IN DOUGLAS COUNTY, COLORADO Analysis. 41 . . . Recommendations 43 Literature 44 Cited. vii �118 List of Tables 1.1 2.1 2.2 2.3 2.4 2.5 2.6 High counts of plains sharp-tailed County, Colorado 1986-88 .... Daily and seasonal time periods grouse behaviors. . . . grouse, Douglas 4. for plains sharp-tailed . . . . . 12 Number of plains sharp-tailed grouse observed and captured in Douglas County, Colorado, 1987-88 15 Distances (km) moved seasonally by plains sharp-tailed grouse in Douglas County, Colorado, 1987-88 ... 16 Dominant plant species (%) at plains sharp-tailed use and random sites. . .. . . 31 Clump speci~s random sites. (%) at plains sharp-tailed . Plant group cover (%) at feeding-loafing of plains sharp-tailed grouse viii grouse grouse use and . 32 and nest sites . 33 �119 List of Figures Figure 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.12 Distribution of plains sharp-tailed Douglas County, Colorado, 1986-88 Home range size of 10 male plains Cherokee Lek, spring 1987-88 grouse use areas sharp-tailed Home range size of 6 male plains Cherokee Lek, summer 1987-88 sharp-tailed Home range size of 3 male plains Cherokee Lek, fall 1987-88 sharp-tailed grouse, . 17 18 grouse, 19 . sharp-tailed . sharp-tailed grouse, 20 grouse, 21 . Horne range size of 1 female plains sharp-tailed Dakin Lek, spring-summer 1987 . . . . . . . . Horne range size of 2 male plains sharp-tailed Indian Meadows Lek, spring 1988 . . . . .. 10 grouse, . Home range size of 2 female plains Cherokee Lek, spring 1988 Home range size of 3 male plains Dakin Lek, spring 1987.. in . grouse, 22 grouse, .... 23 Structural variables at plains sharp-tailed grouse use and random sites in spring (Mar-May), Cherokee Lek ... 25 Structural variables at plains sharp-tailed grouse use and random sites in summer (Jun-Aug), Cherokee Lek ... 26 Structural variables at plains sharp-tailed grouse use and random sites in summer (Jun-Aug), Indian Meadows Lek. 28 Structural variables at plains sharp-tailed grouse use and random sites in summer (Jun-Aug), Dakin Lek .... 29 ix �120 Chapter DISTRIBUTION AND ABUNDANCE IN DOUGLAS 1 OF PLAINS AND ELBERT SHARP-TAILED COUNTIES, GROUSE COLORADO INTRODUCTION Plains sharp-tailed historically Mountains occupied from Arapahoe, sharp-tailed in Larimer Douglas, and Niedrach 1914). However, With by Snyder 1965). 1912), Boulder (1897) and Sclater The plains declined along 1909), Douglas (Aiken and Warren (1912) reported Apparently, race of sharp-tailed to all sharp-tailed and the foothills dramatically by Lincoln Lincoln, This race of (Henderson in Colorado. from Colorado name was applied 1912) south into El are in the Denver was most abundant and abundance was described of the Rocky this area, specimens and Yuma counties grouse were not common and 1887 (Cooke 1897). Colorado Within 1965), and El Paso counties distribution subspecies 1912). (Bailey and Niedrach both Cooke jamesii) 1914) and east to Kit Carson, grouse historically (Bailey jamesii) (Cooke 1897, Sclater Elbert, History phasianellus east of the Front Range (Cooke 1897, Sc1ater sharp-tailed (Tympanuchus (Cooke 1897, Sclater of Natural species' County (Aiken and Warren Yuma counties Museum habitats from Larimer Paso County grouse that the between grouse 1877 (I. p. (1917)_ and the grouse in eastern (1939). the exception columbianus) in northwest sharp-tailed grouse of a study of sharp-tailed Colorado in Colorado grouse (Dargen et al. 1942), appear in the literature (I. p. few records of from the early �121 2 1900's until the 1960's. Fish initiated Colorado a survey (Rogers described reported During Elbert, on habitat grouse sharp-tailed Elbert counties grouse Stearns and possibly Rogers (1962-65) in El Paso, grouse Colorado (1964) and greater (1969) reported to occur Phillips, in (1968) and Evans sharp-tailed were known grouse in east-central and El Paso counties) used by a hybrid of Game and of sharp-tailed (1. cupido) in Yuma County. plains Department the same period, used by sharp-tailed Douglas, prairie-chicken Yuma of the distribution 1969). habitats (Arapahoe, In 1962, the Colorado that in Douglas Sedgwick, and Teller, and counties. Numbers of plains Colorado are unknown present. Personnel although of 200-300 Div. Wildl. 1978). tailed Endangered grouse most recent birds being Division than at of Wildlife commonly 1960's in the early as endangered (Kahn 1979) resulted historically higher 1970's Act of 1973 resulted classified inventory that occurred from the early Discussions Species grouse they were obviously of the Colorado an estimate federal sharp-tailed in used to late 1970's (Colo. and enactment of the in the plains in Colorado sharp- in 1976. in an estimate The of 175-200 birds. The objectives distribution Douglas and estimate and Elbert observed males historical of this study were the abundance counties. and females to delineate Included of plains the present sharp-tailed are data on maximum at each known grouse number lek, and the status of of inactive leks. STUDY AREA The study area extended County east to Kiowa from the foothills and from northern Douglas in western County in Douglas to northern El �122 3 Paso County. Elevations in the southwest. by broken The western foothills 2000 m in height eastern region (Stearns separated consisted little changes. was between 35 and 60 em with grass Eragrostis The short-grass by low diurnal over a 30-year occurring prairie gambelii, Cercocarpus and riparian was dominated trichodes, and Yucca (Stearns precipitation The and plains and wide in the area were: pine prairie tectorum, spp. foothills winds, than regions. was characterized the majority types shrubland, The mid-grass comata, into 3 distinct rain, moderate annual greater period in late spring 1974). vegetative prairies, land. Mean foothills rolling The climate to 2,438 m of the area was characterized Two parallel of intermixed temperature The major one-third the study area 1979). sunny days, (U.S. Dep. Agric. from 1,554 m in the northeast and buttes. 1968, Kahn humidity, varied glauca. forests, Shrub lands were montanus, Forbs were common surveys and counts of birds (Evans gracilis, dominated Rhus aromatica, 1968). spp., ~ longifolia by Bouteloua and short- and cultivated by Andropogon and Calamovilfa was dominated mid-grass Bromus by Quercus Poa pratensis, in all habitat 1964). and Carex types. METHODS Roadside from 0430 Roadside scope, private to 0900 hours surveys during for sharp-tailed Landowners interviewed through May with Surveys were 3-5 minute stops microphone, taken along every leks were conducted 1986 and 1988. were aided by use of a parabolic and binoculars. ranches March on active county roads 0.8 km to listen spotting and on and look grouse. with known to provide historical historical leks were contacted data and status and of current populations �123 4 on their land. Where to obtain coverage data were plotted necessary, of ranches field searches with on topographic suitable maps were conducted appearing to establish on foot habitat. priority Location areas to be searched. RESULTS Plains 6 active sharp-tailed grouse were only located leks documented apparently inactive, the vicinity. (Table 1.1). although Fifty-three 4.3 females/lek) were males observed Table 1.1. High counts Colorado 1986-88. male in Douglas Two historical sharp-tailed on active of plains with leks were grouse (R = 8.8 males/lek) County were observed in (~ = and 26 females leks. sharp-tailed grouse, Douglas County, Males Females Cherokee 10 7 Dakin 11 4 Woodho~se 16 11 Greenland 5 0 Indian Meadows 3 0 Lincoln Mountain 8 4 Rancha 2 0 2 0 Lek Highlands Winkler Rancha aInactive although The 6 lek locations topography. non-displaying were The communities isolated of Castle males were observed in 2 distinct in the area. areas by local Rock and Larkspur lie between the �124 5 2 areas decreasing the probability leks were in Elb~rt observed If only one-half high count (Robel the population apparently is doubtful grouse during at the 6 active leks was between leks were grouse was greater No active the and Boag 1974) and the sex ratio was historical sharp-tailed 1986-88 in an area were present sharp-tailed that all active of the plains during of the males of plains to west movement. County. 1970, Rippin inactive of east population and 2 200 and 225 birds. located. Thus, It the minimum in Douglas 1:1, County, size Colorado than 200 birds. DISCUSSION The cumulative effect developments, intensified the available habitat Elbert counties County prior of conversion grazing, for plains (Chapter 2). and wildfire sharp-tailed to 1986, but no birds Rangeland than in Douglas County, The key factors in the apparent in Elbert grouse County County appear conducted shrub suburban of plains and in Elbert has a smaller disappearance has reduced in surveys but there are also fewer to suburban in Douglas existed were observed in Elbert rangeland suppression A small population 1986 and 1988. grouse of native in component developments. sharp-tailed to be the lack of nesting and escape cover. Key factors appear plains to be loss of native conifers as a result grazing. grouse affecting leks Development on 2 factors, rangeland surrounding proceeding for plains development grouse to development, of fire suppression, is currently The future sharp-tailed in Douglas invasion and intensive sharp-tailed or is in preliminary and habitat. grouse stages. in Douglas If development of livestock 5 of the 8 documented sharp-tailed County County continues depends a~ its �125 6 present rate, useful decline. The key needs km) with interspersion If habitat habitat hope habitats management, improvement for survival for sharp-tailed for sharp-tailed grouse of native grasses, including maintaining is not initiated of plains grouse are open forbs, open space, grouse land and shrubs in the near sharp-tailed will markedly future, (1.6 x 3.2 (Chapter 2). or intensive there in Douglas is little County, Colorado. LITERATURE CITED Aiken, C. E. H., and E. R. Warren. 1914. Colorado. Colorado Coll. Sci. Series The birds of El Paso County, 12:455-603. Bailey, A. M., and R. J. Niedrach. 1965. Denver Mus. Nat. Hist., Denver, Colo. Birds of Colorado. 454pp. Vol. 1. Colorado Division of Wildlife. 1978. Essential habitat for threatened and endangered wildlife in Colorado. Colorado Div. Wildl., Denver. 84pp. Cooke, W. W. 1897. 37. l44pp. The birds of Colorado. Colorado Dargan, L. M., H. R. Shepherd, and R. N. Randall. tailed grouse in Moffat and Routt counties. Dep., Sage Grouse Surv., Vol. 4. 28pp. Agric. Coll. Bull. 1942. Data on sharpColorado Game and Fish Evans, K. E. 1964. Habitat evaluation of the greater pra1r1e chicken in Colorado. M.S. Thesis, Colorado State Univ., Fort Collins. 98pp. Henderson, J. Colorado. Kahn, 1909. Univ. An annotated list of birds of Boulder Colorado Studies 6:219-242. R. 1979. Prairie sharp-tailed grouse Colorado Div. Wildl., Denver. 12pp. segment. Lincoln, F. C. 1917. A review of the Pedioecetes Biol. Soc. Washington 30:83-86. Rippin, A. B., and D. A. Boag. male sharp-tailed grouse. Robel, R. J. prairie 1970. chicken 1974. Recruitment J. Wildl. Manage. County, Unpubl. Rep., in Colorado. Proc. to populations 38:616-621. of Possible role of behavior in regulating greater populations. J. Wildl. Manage. 34:306-312. Rogers, G. E. 1969. The sharp-tailed grouse in Colorado. Div. Game, Fish and Parks Tech. Publ. 23. 94pp. Colorado �126 7 Sc1ater, W. H. 1912. A history Co., London, U.K. 576pp. Snyder, L. L. 1939. 56:184-185. Great of the birds Plains races of Colorado. of sharp-tailed Stearns, F. D. 1968. Sharp-tailed grouse density Colorado related to selected habitat factors. Colorado State Univ., Fort Collins. 133pp. U. S. Department of Agriculture. 1974. area, Colorado. u.s. Dep. Agric., D.C. 129pp. Witherby grouse. and Auk in east-central M.S. Thesis, Soil survey of Castle Rock Soil Conserv. Serv., Washington, �127 Chapter SEASONAL HABITAT 2 USE BY PLAINS IN DOUGLAS COUNTY, SHARP-TAILED GROUSE COLORADO INTRODUCTION Plains occupy sharp-tailed suitable into southern grouse habitats Canada from northeastern (Aldrich range of this subspecies periphery, (Aldrich largely favoring and shrubs sharp-tailed In Colorado, suitable habitats Larimer County Boulder along the mixture (Sisson Nebraska The its southern grazing sharp-tailed by man is a dominant grouse. Range of grasses, forbs, 1976). grouse historically 1912) south 1912). occupied (1897) and Sclater grouse were not common Lincoln, in Colorado. and Yuma This race of sharp-tailed 1909), Douglas (Aiken and Warren in Larimer (Bailey grouse (Cooke 1897, and Niedrach 1914). (1912) reported Apparently, 1877 and 1887 (Cooke 1897). from into El Paso County along the foothills (Henderson and El Paso counties between 1965). have been altered 1914) and east to Kit Carson, Sclater Both Cooke and western and Niedrach reduced jamesii) east of the Front Range of the Rocky Mountains most abundant uncommon has altered sharp-tailed was apparently 1965), Colorado grouse use for cover (Cooke 1897, Sclater 1912), phasianellus Livestock range of plains livestock plains 1980). (Cooke 1897, Sclater (Aiken and Warren counties former habitats and Graul land use in the remaining management 1963, Bailey has been greatly because 1963, Miller (Tympanuchus that sharp-tailed the species At present, became �128 9 self-sustaining populations occur only in Douglas of plains sharp-tailed County within Colorado. This study was initiated remnant population Colorado. grouse are known to in 1987 to describe habitats of plains sharp-tailed used by the grouse in Douglas County, Included were data on seasonal habitat use and home ranges. STUDY AREA The study area was in the foothills County, Colorado (Fig. 2.1). and tablelands Elevation ranged from 1,850 to 2200 m. The climate was high inland continental Mountains and the Palmer Divide as modified (U,S. Dep. Agric. climatic characteristics variable winds, and a Ivide temperature included low precipitation, (U.S. Dep. Agric. 1974). period receiving 1974). range. The temperature Upland deposits. gravelly 16-20% of the annual (Dec-Feb) was the driest (U.S. Dep. Agric. 1974). rolling to broken of Plum and Cherry creeks. widely, but were primarily red arkose, sedimentary, calcareous, tablelands dissected Soil parent materials varied arkosic fans and pedisediments, and red sedimentary bedrock, Soils were loam to clay in the western in the eastern low humidity, ranged from -30 to 38°C with an annual mean of areas were mOderately by tributaries Winter General The annual precipitation only 8-9% of the annual moisture 19°C (U.S. Dep. Agric. by the Rocky 1974). was 37-44 cm with May the wettest month receiving moisture of Douglas and Eolian section and sandy to section of the study area (U.S. Dep. Agric. 1974). Gambel oak (Quercus gambelii) (Cercocarpus Fragrant montanus) and true mountainmahogany were the dominant sumac (Rhus aromatica) shrubs in uplands and rabbitbrush areas. (Chrvsothanmus spp.) �129 10 Nt 8 S 6 (J) N at '" 7 -i 0 ~ 8 z (J) J: -0 !:E 9 10 71 70 69 68 RANGE 67 66 (W) Rg. 2.1. Distribution of plains sharp-tailed grouse use areas, Douglas County, Colorado, 1986-88. �130 11 were common Melilotus, included understory shrubs. Descurainia, Poa, Bromus, ranching, housing Understory and Yucca. Koeleria, developments, forbs Dominant included grasses in upland and Agropvron. Primary and small farming. scale Astragalus, areas land uses were METHODS Plains Walk-in sharp-tailed traps with tailed grouse the lek. powered were captured et al. 1982). leg bands, capture, radio and plastic individual birds' time of capture packages. radio failure. element Yagi the birds. Geologic Survey times. sites were to direct sharp- or at the periphery of nets and spotlight were classified and fitted to designate to sex with a solar- serially-numbered 15-25 g and were aluminum lek of less than 3% of at lek, feeding-loafing, (use sites). birds located Locations using interpretation time for birds relocated map by season classified (Table 2.1). until a portable were not taken to adjust to predated or receiver and 3- on a 7.5-minute and activity. during escape, by triangulation was plotted 2-3 times each week were Radiolocations were ascertained Each observation topographic All behaviors facilitate coded for 3 days to allow Grouse antenna. to locate color Birds were periodically flushing made 1944), 1980), weighed were obtained roost, .nest, and brood radio grouse for study. body weight. Radiolocations from (Amstrup Radios cannon (Ammann bandettes sex, and age. with chosen traps in the middle Captured et al. 1967) and age poncho-mounted leks were leads connecting into them were placed (Giesen (Henderson at 4 active chicken-wire Some birds trapping grouse randomly by time periods or by U.S. Attempts were selected use or location to �131 12 Table 2.1. Daily grouse behaviors. and seasonal time periods Behavior for plains sharp-tailed Time period/location Feeding-loafing 0.5 hours after Roosting 0.5 hours before Escape Area Lek 0.5 hours to where sunrise to 0.5 hours before sunset sunset to 0.5 hours before sunrise bird before flushed sunrise to 3 hours after sunrise, 1 Mar to 30 May Nesting 15 May to 15 Jul, hens Brooding Hens with chicks, Radiolocations polygon were pooled was drawn around behavior. Vegetation site and season. obtained using a random 3.2 km2 area defined initial year started with measurements polygon was met. least taken separately for each use with use sites were with all points grouse within locations samples from a randomly to sample generated taken at 25-m intervals were obtained, sample 1 m of the random vegetation were used If the edge of the use polygon Each vegetation residual generator transects polygon within were sites for comparison number (> 2) for each of observations by all sharp-tailed random sampling sufficient concentrations for each use site and a a 1.6 x during the of study. Stratified Vegetation bi-weekly measurements Random 1 Jul to 31 Aug included point, that could 50% cover measured a second canopy distance supply within a use the edge of the was met before transect cover, was mean plant cover a sharp-tailed on a spherical point until random to clump use sites. densiometer), started. height (any live or grouse with height, at width, and �132 13 length of clump clump cover, species. cardinal species were from the sample and random measurements nesting/brooding species were site, sites taken to test for habitat 10 times within sampling derived (121 possible feeding-loafing canopy cover Home estimates Blowhowiak means. Aug), contours to illustrate Movements and fall were Procedure 1 summer, structural spring compared based samples around high use areas categorized on a lOom was used to the nearest using seasonal harmonic were constructed for and 25-m grid for and study population. to calculate 1%. Dixon and and total MCPAAL means for (Stuwe and using a 10 x 10 at 10, 25, 50, and 95% calculated for spring were (Mielke (2 spring Indian Meadows). variables summer between (MRPP) collected habitat versus generator were analyzed mean measure characteristics sets of data were Dakin; Points sites, through (Mar-May), harmonic summer (Jun- (Sep-Nov). Vegetation Permutation sites. A 0.5-m2 quadrat and movements 1985) was used intervals for nest samples. for each bird Isopleth number feeding-loafing and cover was estimated (1980) harmonic radio locations points) and random range analysis Chapman's grid. sample a random selection. 50 m of a general a 1.6 x 3.2 km2 area for random grid in each of the 4 at feeding-loafing, 20 times within using and point. and 20 within were at the random point, taken once cover was estimated nesting/brooding, Random plant All measurements directions Plant dominant habitat, examined using the Multi-Response et al. 1976, Mielke and 2 summer, Tests Cherokee; of data distribution were performed and between sites due to differing 1979). on random versus use categories. grazing intensities. Six 1 summer, for 6 use sites, Data were not �133 14 Plant standing data were pooled dead). MRPP was used into 3 categories Percentages were calculated to test for differences feeding-loafing, nesting, and random (grasses/ forbs, shrubs, for use and random between plant cover sites. groups at sites. RESULTS Trapping Thirty-nine in walk-in spotlight of 42 plains traps. One bird was caught and 2 were recaptures). The most effective Eighteen different at the Dakin (Table Lek, 3 at Lincoln of sharp-tailed of 11 males males and for short periods (Table were grouse in the center adult males. Lek, were of the Thirteen 5 were and 2 at the Indian captured Meadows Lek at lek sites varied at the Cherokee study making observed site. it difficvlt study site to a low of 3 Hens visited to obtain from a leks infrequently reasonable counts 2.2). Movements and Home Range Plains summer. sharp-tailed They used moving movements marked grouse and 4 females at the Indian Meadows while net and sharp-tailed at the Cherokee Mountain, caught (19 of 42 captures lines of traps placed were captured were a long handled to direct captured captured 2.2). Numbers high using set-up of 23 individuals individuals grouse caught with a cannon-net into traps was 3 separate lek. sharp-tailed the same transitional between were grouse used different seldom winter habitat and summer habitats. greater hen was predated habitats in winter in spring Daily than 2 km (Table 2.3), and fall and seasonal although 8 km from the last site at which and one radio- she was �134 15 located. Longer movements between leks probably occurred but were not observed. Table 2.2. Number of plains sharp-tailed in Douglas County, Colorado, 1987-88. grouse observed and captured Captured Observed M Lek F M F 1987 13 2 7 1 7 4 3 2 7 o 3 o Cherokee 9 4 3 2 Indian Meadows 3 o 2 o 39 10 18 5 Cherokee Dakin Lincoln Mountain 1988 Totals Spring movements visitation, dominated grouse habitats. and flushed movements August. areas feeding-loafing fed, loafed, habitat were largest and roosted grassland-forb shrub-dominated winter. season progressed, in grass/forb to areas dominated The longest areas lek to oakbrush- sharp-tailed typical of summer by mountainmahogany. Summer 1.6 km2 at all study sites from late May to middaily movements areas. habitats areas included on ridges near leks, and escape As the breeding were within to escape as daily activity of 500 m were from feeding-loafing In late August through and September transitional (Gambel oak) where grouse moved grass-shrub they remained habitats through the from into �135 16 Table 2.3. Distances (km) moved seasonally grouse in Douglas County, Colorado, 1987-88. by plains sharp-tailed Males = 13) Females (n = 5) (n Period n n Range locations 163 0.15-8.0 0.125-0.50 64 0.0-l.25 131 0.375-2.50 25 0.35-2.5 23 0.125-2.25 5 Spring (Mar-May) 439 0.25-3.25 Summer (Jun-Aug) 304 Fall (Sep-Nov) Winter (Dec-Feb) The area used by marked (diam.), respectively at the Indian Meadows Home females ranges leks. of males were more continuous One hen nested visit throughout 0.10-2.25 3.2 and 4.8 km Sharp-tailed during grouse summer. and smaller than those of 4.8 km from lek of capture the summer. the summer Males and were remained observed and within to the lek. Characteristics Habitat Measurements Cherokee of habitat Lek were based characteristics on 7 males data at Indian Meadows radio-marked sufficient at Lincoln on 3 males were based Mountain data could be collected. for birds in 1987 and 3 males Data at the Dakin Lek were based 1987, while males and Dakin in the same area throughout infrequently ·grouse was site were only followed 500 m of lek of capture 1988. sharp-tailed at Cherokee (Figs. 2.2-2.8). remained .Range locations marked at the and 2 females and 1 female on 2 males during in 1988. in 1987 were predated in before Three �136 17 • •• •• ••I • • .. ~ '" • • •• •• • • • •• • • Rg. 2.2. Home range size of 10 male plains sharp-tailed grouse, Cherokee Lek, spring 1987-88. (Hectares in each contour interval are: 10% = 1.73. 25% = 14.82, 50% = 35.86, 95% 220.13). = �137 18 • • • • • • • • • •• •• • • • Fig. 2.3. Home range size of 6 male plains sharp-tailed grouse, Cherokee Lek, summer 1987-88. (Hectares in each contour interval are: 10% = 1.54, 25% = 6.03,50% = 15.71,95% = 103.84). �138 19 • Fig. 2.4. Home range size of 3 male plains sharp-tailed grouse, Cherokee Lek, fall 1987-88. (Hectares in each contour interval are: 10% = 2.83, 25% = 9.99, 50% 53.28, 95% = 363.28). = �139 20 • • Rg. 2.5. Home range size of 2 female plains sharp-tailed grouse, Cherokee Lek, spring 1988. (Hectares in each contour interval are: 10% 3.55, 25% 25.78, = 50% = 67.95: 95% = 306.96). = �140 21 • • • • Fig. 2.6. Home range size of 3 male plains sharp-tailed grouse, Dakin Lek, spring 1987. (Hectares in each contour interval are: 10% = 2.68, 25% = 7.5, 50% = 19.17, 95% = 125.32). �141 22 ffJ. Rg. 2.7. Home range size of 1 female plains sharp-telleo grouse, Dakin Lek, spring (upper left)· Summer (lower right) 1987. Hectares in each contour interval are: 10% = 6.84, 25% = 10.69, 50% = 48.17, 95% = 139.13, 95% = 884.01). �142 22 • Fig. 2.8. Home range size of 2 male plains sharp-tailed grouse, Indian Meadows Lek, spring 1988. (Hectares in each contour interval are: 10% = 2.62, 25% = 10.97, 50% = 27.32,95% = 128.32). �143 24 Data from the Cherokee were used in analysis pooled. summer of use versus and Indian Meadows random sites. Feeding-loafing differed All variables (f < 0.05) from random (f < differed and roosting 0.05) sites sites during leks were no site and the data during spring and summer with strong height, (f selection width, and (Figs. 2.9-2.10). Lek and nesting from random sites sites during length and greater sites had greater length cover, distance canopy and less distance Escape sites and clump clump height, randomly differed (Figs. 2.9-2.10). sites. (f < Canopy and Nest width, and (Fig. 2.10). 0.05) from random cover, plant (f < 0.05) from random sites, but differed and length had a 1 in 4 probability were examined lek, and nest sites within and 1988 from Cherokee sharp-tailed grouse sites during among feeding-loafing, each study were pooled of occurring selected for similar spring when be similar sites, but differed feeding-loafing, cover escape, Data collected feeding-loafing, the best available Canopy between site. roosting, and clump width escape, during for use site comparisons. (Figs. 2.9-2.10). between width, clump height, sites Lek (Figs. 2.9-2.10). Differences escape than random than random and summer 2.9-2.10). clump height, cover (f < 0.05) differed (Figs. plant height, to clumps distance width, plant height, cover, in spring and summer measured to clump for 7 of 12 variables height, spring for all variables sites had less canopy sites (1988) for 11 of 12 variables. < 0.01) against random sites for clump distance, length There (f > 0.05) between years at the Cherokee differences were (1987-88) 1987 Plains roosting, and cover was shrubs and length appeared to (f < 0.05) for all variables and lek sites, but not for roosting. �f-' -l> ·1> -- 100 ffi 60 o 40 > o 1- 0 ~--.-- A FL AO E L 30 12 25 10 8 ~ ~ 6 4 w 20 14 a: C/) oR 80 a: w w I~ C/) 20 a: ~ 15 w ~ 0 A 12 251----- 0 A I. FL AO E 0 L E L A FL AO E L CLUMP LENGTH I :tlill A FL AO E 25 20 a: ~ 15 w ~ I L 10 5 0 N Vl C/) !::tlill 6 2 AO 30 30 4 FL CLUMP WIDTH 14 10 8 10 5 2 CLUMP HEIGHT C/) CLUMP DISTANCE PLANT HEIGHT CANOPY COVER A FL AO E Rg. 2.9. Structural variables at plains sharp-tailed grouse use and random sites in spring (Mar-May), Cherokee Lek. (R= random, n = 42; FL = feeding-loafing, n = 106; RO= roosting, n = 54; E = escape, n = 54; L = lek, n = 20). L �CLUMP DISTANCE PLANT HEIGHT CANOPY COVER 14 100 #. -a: w > 0 o I 80 60 40 20 12 (j) a: w 10 8 tD 6 ~ 4 (j) a: 2 _._----- 0 A 1 ---- FL AO E 0 NE a: w rw ~ - A FL ._ -AO E ~ w ~ 1 10 5 0 A NE 14 30 30' 12 25 25 10 8 4 2 0 20 (j) 20 ~ 15 ~ 15 ~ 10 ~ 10 w 6 A .11 FL AO E 5 NE 0·-----, A AO E NE IV o- I (j) a: FL CLUMP LENGTH CLUMP WIDTH CLUMP HEIGHT (j) 15 a: w I FL AO 5 E NE 0 A FL AD E NE Rg, 2.10. Structural variables at plains sharp-tailed grouse use and random sites in summer (Jun-Aug), Cherokee Lek. (A = random, n = 101; FL = feeding-loafing, n = 144; AO = roosting, n = 51; E = escape, n = 69; NE = nest, n = 5). r-" -I> \..I, �146 27 Canopy cover and clump width intermediate tailed between grouse width, loafing and roosting comparisons Indian site. Escape sites were aromatica, closer clumps usually clump for feeding- (E < Lek sites had less All other seasonal marked at Cherokee, Dakin, of Stipa dominated feeding-loafing comata and Yucca by Cercocarpus glauca. montanus, than any other use site and were within clumps (3 nests) gambelii at Nest dead vegetation Quercus and communities. or Svrnphoricarpos albus (2 nests) 2.11-2.12). sharp-tailed changed grouse true mountainmahogany forbs. In summer, grouse gambel oak for escape spring and summer categories. vegetation predators. for escape sites selected cover. that could from spring dominated habitat sites with to clumped and length (Figs. 2.9-2.10). as by tall shrubs by grasses true mountainmahogany vegetation and or (E > 0.05) between among grouse were not more provide to summer dominated There was no difference sharp-tailed Clump width from habitat to summer for distance Plains dramatically moved through clumped Sharp- (E < 0.05), except for clump distance or less frequently Use site selection plains distances sites. by birds to large cover and escape. plant height, sites were near or within in areas sites had greater of standing clump sites were < 0.05). Roosting but were (Figs. CE leks differed sites, Rhus cover, than all other use sites. use site selection Meadows the Dakin and greater than at escape differed Summer for lower canopy and length 0.05) vegetation at roosting those used for feeding-loafing selected height, and length at least minimal also did not differ use than 14 m from cover between (50%) from seasons �a: ~ 100 4 w 60 en a: .,_ 0 40 ~ > 80 w w 0 20 0' en a: .,_ 2 1.1 , FL AD 0 E 25 3 1 ~~A 30 _I 5 ~ - CLUMP DISTANCE PLANT HEIGHT CANOPY COVER FL A AD w w ~ 20 15 10 5 0 A E FL AD E N CLUMP HEIGHT 30 - I 25~_ en a: .,_ w w ~ CLUMP WIDTH ::[1 30 30 25 25 en .,_a: 20 w w 15 ~ 10 5 5 0 01--A FL AD E CLUMP LENGTH I. A FL AD en a: .,_ 20 w w 15 ~ 10 ('C 5 I E 0 A FL AD E Rg. 2.11. Structural variables at plains sharp-tailed grouse use and random sites in summer (Jun-Aug), Indian Meadows Lek. (A = random, n = 88; FL = feeding-loafing, n = 46; AD = roosting, n = 39, E = escape, n = 66). t·1> -I �I-' ~ 00 CLUMP DISTANCE PLANT HEIGHT CANOPY COVER 4 -cfffi > o 100 3 80 C/) 60 w tw 40 ~ a: 0 ~ 0 FL AO .1 0 E I I 15 a: w t- w ~ I. FL AO ~ E 10 30 25 25 20 C/) 20 ~ 15 ~ 15 a: W Of FL --I AO E ~ FL AO E CLUMP LENGTH 30 C/) a: 5 10 8 6 4 2 0 CLUMP WIDTH CLUMP HEIGHT 20 w tw 2 20 C/) 16 14 12 N '0 W ~ 10 5 0 10 5 FL AO E 0 FL AO E Rg. 2.12. Structural variables at plains sharp-tailed grouse use and random sites in summer (Jun-Aug), Dakin Lek. (FL = feeding-loafing, n = 43; AO = roosting, n = 34; E = escape, n = 25). �30 Use versus random sites at the ungrazed (f < 0.05) for 17 of 18 structural variables differed Feeding-loafing areas had greater clump height, distance, sites were typically dense, with random sites. standing versus Escape and width, longer, during and plant than random and closer sites had greater for comparison sites feeding-loafing, (Tables canopy and closer height areas, and less Roosting but were vegetation cover, clumped summer. sites. clumped roosting, higher less than at plant and vegetation than did (grass/forb, shrub, by standing areas as escape for feeding-loafing sites. spring Trees were plants at use grouse at the Shrubs grouse selected and roosting, an available were for and shrub- cover group, at any of the 3 sites. sharp-tailed grouse than was available selected at random They also selected sites and for shrubs tailed dead vegetation. In swruner, sharp-tailed by grasses nesting-brooding. or clump sites during as escape but were not selected plants and escape selected areas dominated of dominant Plains-sharp site were dominated sites. into 3 groups 2.4-2.5). Cherokee vegetation and length at use sites were pooled random Plains cover area (Fig. 2.11). dead) dominated canopy on the edge of feeding-loafing and wider, sites Plants width, less height clump height, random Indian Meadows for areas with more sites against standing for feeding-loafing shrubs at the 2 Dakin nesting/brooding and at feeding-loafing sites (Table 2.6). DISCUSSION Plains seasonal sharp-tailed movements cover used grouse have been between in winter grassland (Hamerstrom reported areas used and Hamerstrom to make extensive for breeding 1951). and woody Use of land for �150 31 Table 2.4. Dominant plant species use and random sites. (%) at plains sharp-tailed grouse Site Category Standing Grasses/forbs Shrubs Feeding-loafing 41 18 41 Roosting 42 2 56 Escape 36 27 37 Feeding-loafing 86 3 11 Roosting 83 2 15 Escape 53 42 5 76 19 5 Feeding-loafing 87 10 3 Roosting 69 16 15 Escape 53 37 10 Feeding-loafing 83 2 15 Roosting 83 5 12 0 100 0 71 14 15 Cherokee Spring Sununer Random Dakin Indian Meadows Escape Random dead �lSl 32 Table 2.5. Clump species random sites. (%) at plains sharp-tailed grouse use and Site Category Standing Grasses/forbs Shrubs Feeding-loafing 25 43 32 Roosting 28 16 56 Escape 18 72 10 Feeding-loafing 76 13 11 Roosting 57 28 15 Escape 28 67 5 72 21 7 Feeding-loafing 77 20 3 Roosting 38 46 15 Escape 57 33 10 Cherokee Spring Sununer Random Dakin Indian Meadows Feeding-loafing 84 Roosting 72 16 12 o 100 o 66 16 18 Escape Random 1 15 dead �I---' l./l N Table 2.6. Plant group cover (%) at feeding-loafing Annual Category Site and nest sites of plains sharp-tailed Perennial Forbs Grasses grouse. Shrubs Standing dead Bare ground 5.4 1.2 1.0 5.6 33.0 13.6 10.6 3.0 42.5 44.6 31.1 11.2 0.0 9.5 15.4 10.7 13 .1 0.0 36.2 37.2 15.7 16.9 0.0 3.7 37.0 23.3 0.0 0.0 Grasses Forbs Cherokee Random 12.0 20.2 8.4 6.1 30.7 50.0 Indian Meadows Random 2.9 17.0 7.1 6.2 4.5 7.9 8.3 12.2 Feeding-i.oafing Dakin Random Nest w w Cherokee Cherokee Cherokee Random Dakin 1 Dakin 2 Random 1 2 3 16.8 2.2 3.1 20.2 16.3 9.3 7.7 6.1 28.9 47.7 33.1 50.0 17.4 11.0 24.4 1.2 2.9 6.4 6.4 5.6 19.5 20.1 24.3 13.6 2.0 3.2 4.1 2.9 4.0 9.8 4.5 11.0 3.2 8.3 40.2 30.4 36.2 2l. 7 18.1 15.7 8.0 0.1 0.0 19.0 40.0 37.0 0.0 0.0 0.0 �153 34 agriculture has reduced and reduced their extensive 1968). Spring, size of areas summer, grouse in Montana 1982). Movements were movements generally Three grouse summer habitat Lek was separated grassland without at Lincoln Sharp-tailed summer home ranges through 1980). averaged The daily campestris) with birds Nebraska cruising rarely between ranged The Cherokee, within Dakin, daily use habitats, contiguity populations The Lincoln by intensively grazed sites moved Dakota during with from winter a maximum grouse nests to sharp-tailed Plains meters area throughout and Indian Meadows may be a key factor at each lek site in Douglas woody grouse cover 1976). seasonal The extent for sharp-tailed 1.6 km in (Sisson sites had distinct County. of 3.2 km. was about the year but all sites were contiguous. of 3.2 km (I. £. from heavy sharp-tailed was 0.9 km in Douglas distance fall and winter than a few hundred a 4.8-km habitat. and leks in Saskatchewan of prairie 1951). birds shrub/grassland. sharp-tailed radius and Hamerstrom available. the lek and winter and Dakin nests in Wisconsin more into data were 1.2 km from the lek with a maximum grouse (Hamerstrom habitat between contiguous Five plains habitat varied habitat. This may be why all radio-marked 1972) and was 1.3 km in North CKobriger County from winter and Yde County habitat and summer habitat. at the Cherokee The mean distance (Pepper winter (Nielsen to spring breeding winter and Wood sharp-tailed in Douglas at the 4 leks for which were predated grouse of male grouse grouse (Johnsgard 1.6 km of leks from oakbrush shrub cover. Mountain within habitat moved sites had contiguous Mountain or migrations sharp-tailed from 1.6 to 4.8 km from winter grass/forb to sharp-tailed and fall distributions of plains Sharp-tailed available grouse of and �154 35 Good quality tailed grouse communities, ecotones particularly apparently important and brushy cover are essential (Hillman anc Jackson (Moyles 1981). habitat grassland grassland-shrub provide Interspersion mixtures optimum habitat composition in determining loafing, roosting, all birds marked The average and lek (grassland escape, height of all vegetation plant height In Douglas Swenson areas) sites (40-80%) for of Nebraska use sites sites (70-171 cm) than available cover (Hamerstrom 1981, Nielsen to and structural (1981) reported sharp-tailed 750 m of cropland. grouse in Wisconsin 50% woody canopy cover. in the Sandhills County, plains sharp-tailed 1981, Swenson the distance woody cover within sharp-tailed Cover at feeding- Many authors cite the occurrence grouse near shrubland 1951, Sisson 1976, Moyles cover. grouse in (33-60 cm) for grassland at shrubland at random sites (15-112 cm). few investigated grouse at all lek sites and seasons. grouse used areas with less height sharp-tailed sharp-tailed more areas) sites (13-43%) was less and nest (shrubland was 21.2 cm (Sisson 1976). and greater of Alberta are generally sharp-tailed County varied by type of use and season. than at random, with extensive (West 1961). The range in canopy cover used by plains Douglas of plant in the parklands Height and density of vegetation than species quality 1973). for sharp- Grange probably of plains and Hamerstrom and Yde 1982), but parameters of shrub land grouse used 100% of the (1948) reported prairie could not tolerate more than Other authors have reported minimUm amounts of shrub cover as 1.5% (Janson 1953), 1-4% (Brown 1968), and 5% (Edminster 1954). �155 36 Shrubland necessary cover was used mainly cover within sharp-tailed grouse use sites require themselves? clumped to escape predators not greater than 14 m for all use site measurements clump vegetation was greater about I hypothesized vegetation to flushing. but what approaching where prior for escape, Distance that plains from to clump except than 50 m distant the cover was lek sites (Cherokee Lek). Grassland use sites had a range of clump distance of 0.8 to 5.8 m while shrubland use sites had an average distance of 0 to 1.5 m. Distance o to clumps at random sites clump ranged from 1.3 to 10 m in spring and to 8 m in summer. Plains structural select were closely scattered cover 1976, Moyles herbaceous in early spring Janson habitat over a 6-year Random plant groups cover), tailed of woody to be 10% shrubs 3.5% weedy proportions grass/forbs and standing dead (5-19% cover). County 1982). for nesting (Blus and Walker sharp-tailed Typical grouse habitat consisted and 1.5% woody at 4 study sites demonstrated were in Douglas also types cover. for sharp- and 90% grassland. present grouse and Yde constructed of cover also grouse cover were component cover, grouse and summer, 1981, Nielsen (1955) evaluated for sharp-tailed areas in South Dakota. optimum measurements report spring when most nests were (1981) believed grouse Do sharp-tailed was an important 21% cropland, selected during 1981, Swenson (1953) and Podoll of 74% grassland, tailed grassland and adjacent period County Many authors vegetation 1966). Swenson with shrubs in Douglas at use sites. communities? associated (Sisson Residual grouse characteristics for plant although used sharp-tailed (76-83% selected cover), In spring, that dominant shrubs plains for 41% grass/forb, (16-19% sharp16% shrub, �156 37 and 43% standing dead cover. used feeding-loafing and 12% standing grass/forb, in Douglas County and roosting sites with 82% grass/forb, dead cover. Sites used for escape averaged vegetation. was quite different Feeding-loafing of 27% grass/forbs, and roosting from dominant 10% standing 30% shrubs, and 43% standing grass/forbs, standing plains dead cover. Clump vegetation sites used for feeding-loafing vegetation 35% in summer was available sharp-tailed with clumped in with an average of 68% had an average of 29% grass/forbs, Dominant dead cover, 72% shrubs, and 21% shrubs, and 11% standing dead cover. dead. plant sites during spring had an while escape sites had an average of 18% grass/forbs, grassland 6% shrubs, 60% shrubs, and 5% standing dead vegetation. Clump cover vegetation average In summer, sharptails Escape site clump 70% shrubs, and 1% plant group and clump group data indicate grouse selected or shrub vegetation for both grassland nearby « that and shrub sites 14 m) for initial escape cover. Of the 4 sites studied, closest agreement the literature. the Dakin and Indian Meadows in structural sites had and plant group data to that reported Both were ungrazed or lightly grazed. Birds at these 2 sites also had smaller home ranges than those at the Cherokee Cherokee site had a patchy distribution lightly grazed areas interspersed mountainmahogany. habitat with areas dominated site. moderate, The and by oakbrush and Summer home ranges were larger, and structural and plant group variables had less agreement other states with plains sharp-tailed Data on plains sharp-tailed similar of intensively, in to other studies with data from grouse. grouse in Douglas County, Colorado were in home range size, distance moved between and �157 38 within seasons, canopy cover, plant height, Lincoln Mountain site differed grouse moved between and plant groups. The from other studies in distance that seasons due to the discontiguity Availability of habitat transitional habitat dominated by grass/forbs of habitat. and shrubs with close by may be most critical to plains sharp- tailed grouse in Douglas County, Colorado. There was adequate habitat for selection escape, and leks at the Cherokee, of feeding/loafing, roosting, Dakin, and Indian Meadows sites. identified in habitat Five nesting similar to that Sisson sites were also (1976) reported in Nebraska. Numbers of sharp-tailed grouse lek sites in Douglas County appear to be stable, but lower than in other states. of sharp-tailed have interchange The patchy distribution grouse in Douglas County suggests between the population lek sites or that intervening habitats may not are unsuitable. If true, loss of a lek site could result in loss of plains sharp-tailed grouse using that particular site. LITERATURE CITED Aiken, C. E. H., and E. R. Warren. 1914. The birds of El Paso County, Colorado. Colorado Coll. Sci. Series 12:455-603. Aldrich, J. W. 1963. Geographic orientation of American Tetraonidae. J. Wildl. Manage. 27:529-545. Ammann, G. A. 1944. Determining age of pinnated grouse. J. Wildl. Manage. 8:170-171. Amstrup, S. C. 1980. A radio-collar Manage. 44:214-217. and sharp-tailed for game birds. J. Wildl. Bailey, A. M., and R. J. Niedrach. 1965. Birds of Colorado. Denver Mus. Nat. Hist., Denver, Colo. 454pp. Vol. 1. Blus, L. J., and J. A. Walker. 1966. Progress reports on the prairie grouse nesting study in the Nebraska Sandhills. Nebraska Bird Rev. 34(2) :23-30. �158 39 Brown, R. L. 1968. Effects of land-use practices on sharp-tailed grouse. Montana Dep. Fish and Game, Job Completion Rep., Fed. Aid Proj. W-9l-R-9, Job II-F. llpp. Cooke, W. W. 1897. 37. l44pp. The birds of Colorado. Colorado Dixon, K. R., and J. A. Chapman. 1980. Harmonic activity area. Ecology 61:1040-1044. Edminster, F. C. 1954. Charles Scribner's Agric. Coll. mean measure American game birds of field Sons, New York, N.Y. 490pp. Bull. of animal and forest. Giesen, K. M., C. E. Braun, and T. J. Schoenberg. 1982. Methods for trapping sage grouse in Colorado. Wildl. Soc. Bull. 10:224-231. Grange, W. B. 1948. Wisconsin grouse problems. Conserv. Dep., Madison. Publ. 328. 3l8pp. Hamerstrom, F. N., and F. Hamerstrom. 1951. tailed grouse in relation to its ecology Midl. Nat. 46:174-226. Wisconsin Mobility of the sharpand distribution. Am. Henderson, F. R., F. W. Brooks, R. E. Wood, and R. B. Dahlgren. 1967. Sexing of prairie grouse by crown feather patterns. J. Wildl. Manage. 31:764-769. Henderson, J. Colorado. 1909. Univ. An annotated list of birds of Boulder Colorado Studies 6:219-242. Hillman, C. N., and W. W. Jackson. in South Dakota. South Dakota Tech. Bull. 3. 64pp. County, 1973. The sharp-tailed grouse Div. Game, Fish and Parks. Janson, R. 1953. Prairie grouse habitat survey, 1950-1952. South Dakota Dep. Game, Fish and Parks Job Completion Rep. P-R Proj. W17-R-7. llpp. Johnsgard, P. A., and R. E. Wood. 1968. interaction between prairie chickens midwest. Wilson Bull. 80:173-188. Distributional changes and and sharp-tailed grouse in the Kobriger, G. D. 1980. Habitat use by nesting and brooding sharptailed grouse in southwestern North Dakota. North Dakota Outdoors 43(1):2-6. Mielke, P. W. 1979. On asymptotic non-normality of MRPP statistics. Commun. Statist. Theor. of null distributions Meth. A8: 1541-1550. _____ , K. J. Berry, and E. S. Johnson. 1976. MUlti-response permutation procedures for a priori classifications. Commun. Statist. Theor. Meth. A5: 1409-1424. �159 40 Miller, G. C., and W. D. Graul. 1980. Status of sharp-tailed grouse in North America. Pages 18-28 in P.A. Vohs, and F. L. Knopf, eds. Proc. Prairie Grouse Symp. Oklahoma State Univ., Stillwater. Moyles, D. L. J. 1981. Seasonal and daily use of plant communities by sharp-tailed grouse (Pedioecetes phasianellus) in the parklands of Alberta. Can. Field-Nat. 95:287-291. Nielsen, L. S., and C. A. Yde. 1982. The effects of rest-rotation grazing on the distribution of sharp-tailed grouse. Pages 147-165 in J.M. Peek and P.D. Dalke, eds. Proc. Wildl.-Livestock Relations Symp., For., Wildl., Range Exp. Stn., Univ. Idaho, Moscow. Pepper, G. W. 1972. The ecology of sharp-tailed grouse during spring and summer in the aspen parklands of Saskatchewan. Saskatchewan Dep. Nat. Resour. Wildl. Rep. 1. 56pp. Podoll, E. 1955. Prairie Grouse habitat study, 1953-1955. South Dakota Dep. Game, Fish and Parks Job Completion Rep. P-R Proj. W17-R-10. 10pp. Sclater, W. H. 1912. A history Co., London, U.K. 576pp. Sisson, L. study. of the birds of Colorado. Witherby and 1976. The sharp-tailed grouse in Nebraska: a research Nebraska Game and Parks Comm., Lincoln. 88pp. Stuwe, M., and C. E. Blowhowiak. 1985. Micro-computer analysis animal locations. Conserv. Res. Center, Natl. Zool. Park, Smithsonian Inst., Washington, D.C. 21pp. for Swenson, J. E. 1981. The hardwood draws of southeastern Montana: their importance to wildlife and vulnerability to man's activities. Pages 37-61 in J. H. Ormiston, ed. Management of riparian ecosystems. Proc. 1981 Meeting, Montana Chapter, The Wildl. Soc. U.S. Department Colorado. 129pp. West, D. R. prairie Wagner, of Agriculture. 1974. Soil survey of Castle Rock area, U.S. Dep. Agric., Soil Conserv. Serv., Washington, D.C. 1961. Thoughts grouse habitat. Okla. 10pp. on factors influencing the quality of 12th Annu. Great Plains Habitat Conf., �160 Chapter MANAGEMENT RECOMMENDATIONS 3 FOR MAINTENANCE OF PLAINS SHARP-TAILED GROUSE IN DOUGLAS COUNTY. COLORADO ANALYSIS Results tailed grouse appear of this study indicate (Tympanuchus that populations phasianellus to be stable at presently jamesii) occupied of plains sharp- in Douglas County However. occupied sites. sites are isolated with little, if any. interchange management sites should be to insure preservation of existing occupied of lek sites and to maintain sharp-tailed slightly snowberry grazed pastures sites were in ungrazed areas dominated spp.). dead vegetation or or clumps of Two of 5 nests were in areas used in and roosting. to moderately by shrubs unbrowsed to heavily to ensure (5) found were in ungrazed in either standing (Symphoricarpos habitats Thus. remain stable or increase. grouse nests summer for feeding/loafing ungrazed and improve surrounding grouse populations All sharp-tailed among sites. Feeding. grazed pastures by livestock. grazed pastures loafing. and roosting with escape to Lek sites were in with shrubs within 200 m for escape cover. The need of plains sharp-tailed and density, status within and standing Douglas Ideal management from grazing grouse for adequate dead vegetation County suggests for sharp-tailed plant height coupled with their isolated a complex management problem. grouse would appear to be retirement of several 40-ha blocks near leks to provide nesting sites, �161 42 and implementation High use areas between of light for sharp-tailed among the contiguity average 2.3 km apart km apart 11 km apart. number This of active 1986-88. attain greater suggests lek sites By lightly greater plant standing management height areas with is possible sharp-tailed local population The minimum documented should be to maintain interchange establish leks and birds a population attending of Wildlife should maintaining populations would tailed grouse sites. easements purchase populations. to 6 in and spring. lek site will If grazing (into and brushy into these areas draws), and thus, it the over time. management The Colorado system sharp-tailed of suitable in Douglas lek sites with Division of Wildlife to document basis. landowners on areas critical (Kahn 1979) winter each on an annual of plains Also, and fall with of 6 active monitoring lek sites were summer grouse a minimum also work with be to investigate conservation among County during stability on 1973) and 4.8 of habitat. of grassland goal of sharp-tailed were vegetation grouse will move greater states on areas, the immediate interspersion may have plains from 10 in 1979 during in size dependent and Jackson or by not grazing in areas beyond surrounding (Hillman and density ranged is largely a lack of contiguity grazing use areas. and seasons. leks in other decreased grouse County 1976), but in Douglas dead vegetation occurs should Active (Sisson in Douglas or use sites in South Dakota in Nebraska in high use sites lek sites, of habitat. systems grouse 16 and 68 ha for different Interchange County grazing number The Colorado to generate grouse. properties to maintenance Division interest Other of in approaches or to acquire of plains sharp- �162 43 RECOMMENDATIONS All active during lek sites should be surveyed peak attendance pastures ranch, within pasture winter every 2 years for active Ranch.--Livestock Cattle should be on a 4 pasture grazed. The stocking grazing supplement food resources. should be mapped monitored limiting The distribution and sharp-tailed to understand rest rotation grouse use patterns to investigate Kimball The pasture use, especially winter by hens. of cattle. more residual vegetation Another these areas. to examine and learn if shrubs are estate A buffer pasture suitability southeast during for sharp-tailed the grouse shrubs) between west of the lek should be leased zone around each excluded cattle on a rest rotation for cover. should be should be allowed 65 ha (containing The Kimball Perry Park Road and the Curtis property be surveyed of the shrub community should be monitored should be created by grazing to on the ranch. No grazing and summer use sites immediately for exclusion the lek site. of the 65-ha ungrazed of the lek should be continued. lease period. 3 ha per could be continued The Frank Woodhouse land use options Property.--Leasing basis with one grouse use of the shrub community (too many or too few). contacted from two 65-ha rate should not exceed of small grain crops on bottomlands use on the rest of the animal unit month on one half of the area surrounding Planting Potential leks. should be excluded 1 km of the lek site. if allowed, of birds present (late Apr or early May) each year. areas should be surveyed Bob Woodhouse for number basis property to leave west of the south of the Cherokee for expansion pasture Lek should of grouse use into �163 44 Pine Cliffe Ranch.--The should be reduced number of cattle grazing and ungrazed Dakin Lek Property.--This with grazing to be excluded. be leased and grazing exclosures property (~ 40 ha) created. should be leased or purchased Pastures reduced this property north of the lek site should also to expand the range of the population. area (100 x 100 m) in the center of the site could be mowed spring to create an artificial Greenland-Lincoln of plains through possibility of expanding numbers grouse in this area should be investigated grazing management timing of grazing). in early lek center. Mountain.--The sharp-tailed An (reduction in grazing Grass and shrub communities for large populations intensity, appear changes in to be suitable of grouse, but only a few exist. Indian Meadows.--Leasing should be investigated. of State school land southwest The intent would be to reduce of the lek livestock numbers. Highlands population habitat and Winkler surveys inventory Further conducted selection, Ranches.--Further sharp-tailed of these areas should be conducted for consideration Research.--If on sharp-tailed as possible along with a reintroduction sites can be leased, research grouse habitat among leased pastures selection, and pastures grouse should be especially managed sites. nest site on a rest rotation basis. LITERATURE CITED 1973. The sharp-tailed grouse in Hillman, C. N., and W. W. Jackson. South Dakota Div. Game, Fish and Parks Tech. Bull. South Dakota. 3. 64pp. Kahn, R. 1979. Prairie sharp-tailed grouse segment. Colorado Div. Wildl., Denver. l2pp. Unpubl. Rep., �164 Sisson. L. 1976. The sharp-tailed grouse in Nebraska: a research study. Nebraska Game and Parks Comm., Lincoln. 88pp. Prepared by An~ag~~ Graduate Research Assistant Approved by __ &a.;;.._=~.:;..·_ _;;;Z;;._,:__ --,-~:::___;,.;;;.__ C1ait E. Braun Wildlife Research Leader �165 INTERIM FINAL REPORT ,. .. .; State of: Colorado Project: W-152-R Upland Bird Research Work Plan: 14 Job _3_ Job Title: Seasonal Movement Period Covered: 01 january Author: A. Schroeder Michael Personnel: and Habitat Use by Greater Prairie-Chickens through 31 December 1989 M. A. Schroeder and G. C. White, Colorado Braun, Colorado Division of Wildlife State University; C. E. ABSTRACT Several hypothesis have been proposed to explain the evolution of clumped (lek mating) from dispersed (territorial mating) polygyny; most recent models suggest that increased female home range size leads to increased female choice for males and/or leks. I propose an alternative, the female tolerance hypothesis, in which decreased intrasexual aggression among females during the breeding season results in increased aggregation of males. Predictions of the female preference and hotspot hypotheses were examined in a population of greater prairie-chickens (Tympanuchus cupido) in northeastern Colorado during 1986-88. Nest-1ek distances were used as indirect measures of home range size. Sixty-six of 89 females (74%) nested closer to a lek other than where captured and 67 of 79 females (85%) visited >1 lek during the breeding season. These results contradicted predictions of the female preference hypothesis. Breeding potential was estimated as a measure of proximity between any given location and nest locations of females. Monte Carlo simulations were used to examine breeding potentials under varying conditions of actual and random lek locations and actual and random distribution of nest locations. Distributions of both leks and nests suppo r t ed .pre9:ictionsof the hotspot hypothesis. Examination of seasonal movement between breeding and wintering ranges indicated that spring migration occurred during February-March and autumn migration occurred during June-August. Most of the variability in timing-of autumn migration for females appeared to be due to their brood status; females without broods migrated earlier than those with broods. The average migration distance between breeding and wintering ranges was 10.6 km for females and 2.9 km for males. Examination of seasonal locations for individuals between years indicated that most greater prairie-chickens displayed site fidelity to both breeding and winter areas. A lek attendance rate of 50% for males has been used to estimate population size for greater prairie-chickens; consequently lek attendance was examined in northeastern Colorado during 1986-90. Observations of 21 radio-marked males �166 indicated they were on leks 95.1% of the time during peak display periods (Mar-Apr); consequently use of 50% as a value for 1ek attendance may result in over-estimates of population size. Mean annual turnover rate of leks was 23.8%; 24 leks were active aIlS years. A dissertation incorporating 5 manuscripts for publication has been submitted to fulfill requirements for the Doctor of Philosophy degree in Fishery and Wildlife Biology. Prepared by ~~~i1~~~J,l~U~ Michael A. Schroeder Graduate Research Assistant Approved &~~=.:...< by _ ..•... =2.:;...:.__._~~;_'....;....:...:=--Clait E. Braun Wildlife Research Leader _ �1..l1 JOB PROGRESS REPORT Colorado State of: Project: W-l52-R Upland Bird Research Work Plan: 17 Job Title: Population Dynamics of White-tailed Ptarmigan Period Covered: Author: : Job _7_ 01 January through 31 December 1989 Clait E. Braun and Kenneth M. Giesen Personnel: Clait e. Braun and Kenneth M. Giesen, Colorado Division of Wildlife ABSTRACT Long-term studies of populations of white-tailed ptarmigan (Lagopus leucurus) were continued at hunted (Mt. Evans) and unhunted (Rocky Mountain National Park) areas in Colorado through 1989. Densities of breeding ptarmigan increased at Mt. Evans and at Rocky Mountain National Park. Nesting success at Mt. Evans was average while it was poor at Rocky Mountain National Park. At least 11% (10.7) of the ptarmigan leg-banded in 1989 at Mt. Evans were harvested during the fall hunting season. ��169 POPULATION DYNAMICS OF WHITE-TAILED PTARMIGAN Clait E. Braun and Kenneth M. Giesen Long-term studies of trends in population size and investigation of reasons for fluctuations in size of tetraonid populations are lacking. Studies on the population dynamics of unhunted and hunted populations of white-tailed ptarmigan were initiated in Colorado in 1966 and have continued essentially uninterrupted at 2 sites. Studies of the unhunted population (Rocky Mountain National Park) identified possible short-term cycles of 7-8 years with an amplitude of 25-30% between high and low breeding densities. Conversely, studies of the manipulated population (hunted) at Mt. Evans have not indicated any cyclic pattern and it would appear that controlled hunting may mask any long-term trend that may occur. This study is designed to examine the question whether white-tailed ptarmigan are truly cyclic and whether hunting affects the apparent oscillations. P. N. OBJECTIVES The goals of this investigation are to be able to predict the length and amplitude of cycles in white-tailed ptarmigan in Colorado, to examine the impact of hunting on cycles, and to clarify underlying causes of the apparent cycles. SEGMENT OBJECTIVES 1. Conduct breeding (May-Jun) and brood (Aug-Sep) censuses ptarmigan using tape-recorded calls of males (breeding) (broods) . 2. Censuses will be conducted on previously established, defined study areas at Mt. Evans (hunted) and at Rocky Mountain National Park (unhunted). 3. Capture (noose poles) and band (aluminum and plastic color-coded bands) all unmarked white-tailed ptarmigan encountered on study areas at Mt. Evans and at Rocky Mountain National Park. 4. Individually identify all ptarmigan observed on study areas at Mt. Evans and Rocky Mountain National Park through use of binoculars. 5. Make hunting season and bag limit recommendations for Mt. Evans and collect hunting data through use of volunteer wing barrels and hunter field checks. 6. Compile data, analyze results, and prepare progress of white-tailed and chicks reports. �STUDY AREA AND METHODS Areas investigated were Mt. Goliath-Mt. Evans in Clear Creek County and at Tombstone Ridge-Sundance Mountain to Fall River Pass in Rocky Mountain National Park in Larimer County. The physiography, geology, location, and vegetation of these study areas have been previously described (Braun 1969, 1971; Braun and Rogers 1971; Giesen 1977). Ptarmigan were located through use of tape-recorded calls (Braun et al. 1973), captured through use of telescoping noose poles (Zwickel and Bendell 1967) as described by Braun and Rogers (1971), and classified to age and sex and banded following Braun and Rogers (1971). Age of chicks was estimated following Giesen and Braun (1979). Numbered plastic bandettes were not used as in earlier years (Braun and Rogers 1971) as a color-code system using up to 4 different colored plastic bandettes was instituted in 1977-78. A check station was operated on the Mt. Evans highway during the opening weekend of the ptarmigan season in that area. A volunteer wing collection station was available to hunters in the area when the check station was not in operation until the season closed. RESULTS AND DISCUSSION Breeding Densities Mt. Evans.--Timing of breeding events in the Mt. Evans area was about the same in 1989 as in 1988. During the May-early June. interval, 15 pairs and 2 single males were identified. Thus, breeding densities increased slightly in 1989 (Table 1). During the breeding season,S of 17 males identified were yearlings while 9 of 15 hens were yearlings. Recruitment of yearlings was lower than in 1988. Rocky Mountain National Park.--Timing of breeding events on the Trail Ridge study area was similar to that in 1988 but 1 week earlier than the long-term (1966-88) average. Surveys of ptarmigan on breeding territories along Trail Ridge Road in RMNP in May and June indicated a minimum population of 67 birds and included 29 pairs and 9 unpaired males. This represents a 34% increase from 1988 and the highest population since 1982. However, this population level is only about half that recorded during peak years in 1969 and 1976 (Table 1). The increased breeding density reflected above average survival of banded adult males from 1988 (31 of 45, 68.9%) and excellent production of chicks in 1988 and their recruitment to 1989. Eight of 25 chicks banded in 1988 returned (32.0%) and yearlings comprised 46.1% of all adult ptarmigan identified in 1989. Nesting Success and Brood Size Mt. Evans.--Twenty-three hens were located during mid July-early September 1989 on or immediately adjacent to the study area. Eleven hens (47.8%) were with broods while 12 were apparently unsuccessful nesters (without chicks). Average brood size to 1 September was good (4.0 chicksfhen). Data from 29 chicks that were banded indicated hatch dates from 27 June to 8 August with only 17% hatching after 16 July. �Rocky Mountain National Park.--Nest success was estimated at <30% as only 4 of 14 hens observed in July-August were with chicks. The low nest success may be partly attributed to hen inexperience as yearlings comprised 62.5% of all hens identified in 1989. Hatch dates calculated from primary molt of chicks indicated the median hatch date was 6 July (range 2-11 Jul). Average brood size was 3.0 chicks(hen. Table 1. 1966-89. White-tailed ptarmigan breeding densities (birds/km2), Colorado Study area Year Rocky Mountain National Park (5.5 km2) Mt. Evans (4.0 km2) 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 11.3 9.8 11.5 12.0 9.6 9.1 8.7 7.8 8.0 11.1 13.5 12.9 10.7 8.7 8.4 8.2 7.8 6.7 5.8 6.0 4.5 6.0 5.4 6.2 3.0 2.7 2.7 2.2 2.0 4.2 7.5 6.2 6.2 6.2 6.7 > 6.0 7.5 10.3 9.5 9.0 6.5 6.5 8.0 8.0 6.5 5.0 7.5 8.0 Harvest Mt, !v.n.,--The hunting season at Mt. Evans in 1989 opened on 16 September and closed on 8 October (23 days) with a bag and possession limit of 3 and 6. Thus, the season was delayed 1 week from the statewide opening as it was in 1981 and 1986-88. The season opening was delayed 2 weeks from 1978 to 1980 and 1982 to 1985, Prior to 1978, experimental seasons were in effect (19701976) or the season opened with the statewide grouse seasons (dates from 17 �Aug to 14 Sep). Unlike 1987 and 1988 when the Kt. Evans road was closed due to reconstruction (Lincoln Lake area in 1987, above Ptarmigan Flats in 1988), the Mt. Evans road was open to Summit Lake from 16 to 29 September when it closed because of snow. Only 6 hunters were checked on 16-17 September. These hunters observed 11 ptarmigan and harvested 8 of which all were banded. Two additional wings (1 wing tag) were received on 25 September in the wing barrel and legs from 3 banded ptarmigan from Mt. Evans were received in the Loveland Pass wing barrel on 30 September. Thus, a minimum of 13 ptarmigan were harvested at Mt. Evans of which 12 (2 wing-tagged only) were banded. Six of the banded birds harvested were banded in 1990 (6/56 - 10.7%) of which 4 were chicks (4/28 - 14.3%). The other banded birds harvested were banded in 1984 (1), 1985 (1), 1986 (1), and 1988 (1). LITERATURE CITED Braun, C. E. 1969. Population dynamics, habitat, and movements of whitetailed ptarmigan in Colorado. Ph.D. Thesis, Colorado State Univ., Fort Collins. l89pp. 1971. Habitat requirements of Colorado white-tailed ptarmigan. West. Assoc. State Game and Fish Comm. 51:284-292. Proc. _____ , and G. E. Rogers. 1971. The white-tailed ptarmigan in Colorado. Colorado Div. Game, Fish and Parks Tech. Pub1. 27. 80pp. _____ , R. K. Schmidt, Jr., and G. E. Rogers. 1973. Census of Colorado whitetailed ptarmigan with tape recorded calls. J. Wildl. Manage. 37:90-93. Giesen, K. M. 1977. Mortality and dispersal of juvenile white-tailed ptarmigan. M.S. Thesis, Colorado State Univ., Fort Collins. 55pp. _____ , and C. E. Braun. 1979. A technique for age determination of juvenile white-tailed ptarmigan. J. Wildl. Manage. 43:508-511. Zwickel, F. C., and J. F. Bendell. J. Wildl. Manage. 31:202-204. 1967. Prepared by Clait E. Braun Wildlife Research Leader Ke~iesen Wildlife Research B A snare for capturing blue grouse. �173 JOB PROGRESS State of: Colorado Project: W-152-R Upland Work Plan: 21 Job Title: Sandsage-B1uestem Period Covered: Author: Personnel: REPORT Warren Bird Research : Job _3_ 01 January Prairie through Renovation 31 December 1989 D. Snyder C. Braun, W. Brown, L. Crooks, T. Davis, J. Heinemann, L. Robb, M. Schroeder and W. Snyder, Colorado Division Wildlife S. Posner, of ABSTRACT Extremely dry weather until mid-May 1989 delayed vegetation growth and reduced soil moisture. Above average precipitation in June, August, and September stimulated vegetation recovery, however, it was extremely dry through fall and early winter. Vegetation phenology through spring was similar to that in 1987-88. Due to favorable precipitation in 1988, the height-density index (HDI) of residual grass-forb vegetation increased similarly on both burned and control transects from 1988 to 1989 on all except burn 1-84. Impacts of prescribed burns could no longer be detected. Sandsage (Artemisia filifolia) had not fully recovered from fire by early spring 1989 on any of the burns based on HDI. Sandsage, like grass-forb vegetation, responded favorably to increased precipitation in 1987 and 1988. Crown cover sampling on the 1-84 and 3-84 burns did not reveal any remaining evidence of fire impact. The HDI of residual switchgrass (Panicum virgatum) within 1985 revegetation sites remained high (4.-38 dm) in early spring 1~89. Within the t-illage renovation test site, 1989 HDI's and crown cover were similar to.-that in previous' years indicating 1986 renovation was no longer Lmpac t Lng t alL, warm- season grasses. Little change Ln vegetation. conditions dur Lng ·1989 was noted within the 1985 spray and spray-burn sites. Monitoring of greater'prairie~chickens (Tympanuchus cupido) indicated most hens ne st e.d near leks which were on private land. Nesting hens did not appear to be attracted to greater HDI of grass-forb vegetation within the Tamarack Prairie, however, sample size was small. All nests were associated with sandsage. High mortality and nest predation occurred in May and early June and was primarily attributed to coyotes (Canis latrans). ��SANDSAGE-BLUESTEM PRAIRIE RENOVATION Warren D. Snyder P. N. OBJECTIVES Test renovation and revegetation techniques for increasing standing residual height-density of grasses, the proportion of tall warm-season grasses within the composition, and for reducing the quantity of sand sagebrush to <30% canopy cover in an ungrazed sandsage-bluestem prairie on the South Tamarack, South Platte Wildlife Area in northeastern Colorado. SEGMENT OBJECTIVES Monitoring follows: of environmental and vegetation conditions and changes continued as 1. Precipitation was monitored throughout the year supplementing data from 4 electronic rain gauges with information from nearby weather stations through the winter months. 2. Soil moisture accumulations, plant phenology, and weather were monitored primarily in spring and especially at the time of controlled burns. 3. Visual obstruction (height-density) measurements were obtained on treatments and controls where applicable in late winter and/or early spring prior to green-up. 4. Crown cover, species composition, and frequency of occurrence measurements were obtained from mid-summer to early fall. 5. Six male .and 7 female greater prairie-chickens were trapped adjacent to the Tamarack Prairie in April 1989 and equipped mounted solar transmitters. Monitoring of their survival, of habitat types for nesting, feeding and loafing, and use Tamarack Prairie was conducted. 6. Data compilation and writing the annual job progress conducted during fall and winter 1989-90. on leks with ponchomovements, use of the report were METHODS Approaches used were described by Snyder (1986~, 1986Q, 1987, 1988) and are outlined in the Segment Objectives. Segment Objective #4 was conducted within the 1984 burn sites and their controls after not being conducted in 1988 and was deleted within the 1985 and 1986 burns. Walk-in traps were placed on leks located near the Tamarack Prairie in early April 1989 to trap greater prairie-chickens. Trapped birds were marked with a numbered aluminum leg band and color-marked with 2 or 3 plastic bandettes. �176 Poncho-mounted, solar-powered, single-stage transmitters were placed on 6 males and 6 females; a 7th hen was instrumented later in April after recove~y of a transmitter from a predated male. Additional males trapped on the leks were banded and released. RESULTS AND DISCUSSION Environmental Conditions Three of 4 automatic precipitation recorders provided continuous data from early spring through fall 1989 and the 4th provided intermittent data due to electrical failure and plugging by rodents. These data were supplemented by U.S. Weather Bureau records from nearby weather stations for winter months. Only a few light showers were received and conditions remained extremely dry from March through 14 May 1989, with the first significant rainfall coming on 15 May. However, above average precipitation was received in June, August, and September and the June through September combined total was above that of the long-term average (Fig. 1). As a consequence, considerable vegetation recovery occurred. October through December remained extremely dry with about 1 dm of snow occurring in mid December. Annual precipitation was near the long-term average (Fig. 1). Soil probe sampling showed only the upper 4-5 dm of soil contained moisture throughout spring 1989 (Table 1). This was considerably less than in previous years of study. April-May averages were 9.9 dm in 1985, 15.6 dm in 1986, and 11.1 dm in both 1987 and 1988. Table 1. Soil moisture accumulations (dm)& based on soil probe during spring 1989, Tamarack Prairie, Colorado. ~ Location 12 West North-central South-central East 3.51 4.65 4.52 3.89 2 3.87 4.70 4.89 4.44 &Mean depth (dm) of 4 probes/location precipitation gauges. Ma 15 4.25 5.78 4.64 samples 31 Jun 9 3.87 6.67 4.64 5.78 4.19 6.73 7.18 6.48 taken near each of the 4 Average monthly temperatures were above normal during March, near normal in April and May, and below normal in June 1989 (Fig. 2). Phenology of vegetation was similar to that of the 2 previous years except that a hard freeze on 1 May and below average soil moisture conditions retarded development and flowering of herbaceous plants. Progression of development was summarized for a selected list of species (Table 2). More favorable precipitation after mid-May observably stimulated growth and flowering of many species. �22 '"' (/) W J: U ....., Z 20 OCT-DEC 18 SEP 16 12 I- 10 I- 8 U 6 a: a. 4 W --, ~ 14 Z 0 « -a-. :------; . AUG , I I .':. ··'··i i··.·· ••··..··." I JUN [~ff~~ MAY _APR JAN-MAR 2 0 X 84 85 86 87 88 89 YEAR Fig. 1. Monthly and annual precipitation (in.) from 1984 through 1989 in relation to the long-term mean, Tamarack Prairie, Colorado. �1~3 80 : JUN 75 ~ i~ (J) ,------, ~ ' . MAY W 70 a: o 65 APR C 60 MAR w W ~ ., .. ' 1 , W a: ::J l- <t 55 SO a: w a. 45 ~ 40 W I- 35 30 x 84 85 86 87 88 89 YEAR Fig. 2. Monthly average temperature (F) from March through June, 84-89 in relation to the long-term mean, as an index to vegetation phenology, Sterling, Colorado. �Table 2. Phenological conditions of selected vegetation during spring 1989, Tamarack Prairie, A r Species 12 Artemisia filifolia ~. l udov ic iana AstragaLus sp. Cymopteris montanus lathyrus polymorphus leucocrinum montanum Mentzel ia nuda Penstemon ~stifolius PhLox andicola Psoralea lanceolata Sphaeralcea coccinea Tradescantia occidentalis Tragopogan sp. avegetation height (em). E=early,M=mediun,L Height-Density 5-7.6a Budded E. budded Basal leaf Emerg. L. bud E. bloom 5-10 2.5 Basal IOhorl 5 Leafing 5-7.6 Dormant Dormant Dormant Dormant Dormant 5-10 2.5-5 Agropyron smithii Bouteloua gracilis Calamovilfa longifolia Panicum virgatum Paspalum stramineum Sporobolus eryptandrus Stipa f.Q!!!2ll ~sp. 18 late,F Leafed CoLorado. Ma 24·27 10 22 M. budded Basal leaf 5.0 F. budded 2.5 Leaf 7.6 BLoom l. bloom 5-7.6 Leaf 5 -7.6 BLoom E. bloom F. bloom 5- 7.6 10 Leafed 2.5 l. bloom L. bloom 7.6-10 10·15 F. bLoom 2.5 5-7.6 15-20 F. bloom l. bLoom Headed 15 E. bLoom l. bLoom 7.6 F. bLoom E. bloom Seeded 10-12.7 5 10 10 5 5-7.6 15-20 Headed 15 5-7.6 15-20 15-25 5-7.6 10-15 7.6-10 Emerging Dormant Dormant 7.6-10 2.5 < 7.6 5 Dormant 10-12.7 E. bloom 5-7.6 15 L. bloom 15 E. heading full. Sampling Within Burned Sites Height-density indices (HDI) of residual grass-forb and sandsage indicated that precipitation subsequent to prescribed burns was the primary factor determining how rapidly vegetation recovered from fire within sandsage dominated rangelands in eastern Colorado. Grass-forb recovery following the 1984 burns required 3 growing seasons (Fig. 3) when annual precipitation was below the long-term average through the 1st two post-burn (1984-85) growing seasons and exceeded the average during the 3rd year (Fig. 1). Recovery following the 1985 and 1986 burns occurred within 2 years (Figs. 4, 5). First-year impact of fire in 1986 was also markedly reduced in comparison with previous years leading to more rapid recovery because of above average precipitation that year (Fig. 5). Although regression analysis did not indicate a strong relationship CR2 ~ 0.11), markedly higher HDI indices of residual grass-forb vegetation were recorded in 1988-89 after years of above average precipitation. Grass-forb HDI declined from 1988 to 1989 only within burn 1-84. That site received less precipitation in 1988 than other locations within the Tamarack Prairie. Greater precipitation was especially evident at burn 3-84 in 1988. Blizzards and/or compacting snows, which sometimes mat grass-forb vegetation, probably interfered with the precipitation-HDI relationship. Lack of major snows during winters 1987-88 and 1988-89 may be one reason subsequent HDI's were above those of preceding years. �180 0.6 0.5 """ E ..._, > "'C 0.4 - t- CONTROL '" (J) Z W 0.3 ,' 0----··--(1 ,, C ,, ,, I t- J: -J: e" -. 0.2 W BURN 0.1 o 84 85 86 87 88 89 YEAR Fig. 3. Height-density (dm) of residual grass-forb vegetation from 1984 (pretreatment) to 1985-89 (post-treatment) within the 1-34 burn and control sites, Tamarack Prairie, Colorado. �1.2 1.1 , 1 , , , , , """" 0.9 "t'J ......, 0.8 , , E > I- - (/) , r , 0.7 I , Z .~ C \;._) BURN W , 0.6 I l- ::I: "-::I: I I I 0.5 I W I 0.4 I I -. CONTROL 0.3 0.2 0.1 85 86 87 88 89 YEAR Fig. 4. Height-density (dm) of residual grass-forb vegetation from 1985 (pretreatment) to 1986-89 (post-treatment) within the 1985 combined burn and control sites, Tamarack Prairie, Colorado. �182 1 , 0.9 r , , , r 0.8 '"E , , 0.7 "'C , I """ > I- - I ,""'_' 0.6 \p (/) Z , , I 0.5 W I BURN C I I- 0.4 ::I: -::I: e" W CONTROL 0.3 0.2 0.1 o 85 86 PRE-BURN 87 88 89 POST-BURN Fig. 5. Height-density (dm) of residual grass-forb vegetation from 1985-86 (pretreatment) to 1987-89 (post-treatment) within the 1986 combined burn and control sites, Tamarack Prairie, Colorado. �Height-density samples from 1985 and 1986 burns provided evidence that fire stimulated increased grass-forb growth during the 2nd growing season. However, this increased growth, if it occurred, apparently was only temporary and sampling in subsequent years did not show continued stimulation (Figs. 4, 5). Apparently changes in HDI of grass-forb vegetation, whether ?ositive or negative, are not long-term. Sand sagebrush usually loses most of its woody, above-ground structure in fires, and therefore, recovers more slowly than grass-forb vegetation (Tables 3-6). Regrowth was not fully regained for several years. However, sandsage. like grass-forb vegetation, responded favorably to increased precipitation i~ 1987 and 1988 and increased HDI's were recorded on all controls. Sandsage within burned sites recovered to pretreatment levels within 3-4 years. Crown Cover, Composition, and Frequency of Occurrence Sampling Covariance analyses were conducted on crown cover data derived from metric belt transects within the 1-84 and 3-84 burns and controls (Tables 7, 8). These had been sampled prior to prescribed burns in late winter 1984 and again during mid to late summer 1984, 1985, 1987, and 1989. In general, there was little evidence of any remaining effect of fire in 1989, either positive or negative, on most species or species groups (Tables 9, 10). Blue grama (Bouteloua gracilis) showed little response to fire on either site. In contrast needle-and-thread grass (Stipa comata), a cool season species, was suppressed by fire through the first growing season, but recovered quickly. Crown cover in 1989 remained lower (f < 0.05) within burned transects than within controls in burn 1-84 when tested against pretreatment indices, however, the opposite occurred within burn 3-84 (Fig. 6). It is doubtful tha: site differences were important, but rather, that needle-and-thread recovered to pretreatment levels by 1987, and sampling error, primarily during pretreatment, was responsible for the discrepancies. Other major grasses, sand dropseed (Sporobolus cryptandrus), pralrle sandreed (Calamovilfa longifolia), and sand bluestem (Andropogon halli) previously responded positively to fire, but the response was not sustained. Among these grasses, sand bluestem seemed to respond most favorably to above average precipitation in recent years. Total warm-season grasses seemed to be enhanced by fire for 2-3 years, but the response was not evident in 1989 (Fig. 7). Crown cover sampling of sandsage occurred after it had attained new annual growth and indicated almost complete recovery of sands age within 2-3 years. In contrast HOI sampling of early spring residual indicated a slower regrowth of woody parts. General trends in sandsage crown cover have been do~~ward since studies were initiated (Fig. 8), whereas HOI provides evidence of increased growth (Tables 3-6). Reasons for these differences are not clear. Crown cover of perennial forbs was lowest in 1985 on all 1984 burns and controls. Increases occurred on both sets of controls in 1987 and 1989 in contrast to little change within the 2 burn sites. However, significant differences, even when data were combined, were not detected between pretreatment to 1989 and 1985 to 1989 intervals. Combined annual forbs, in contrast to perennials, peaked in 1985 on the 2 burns and the 3-84 control and have declined since. However, data within the 1-84 controls has not conformed to that in other samples. �Table 3. Mean height-density (dm) within burn 1-84 and controls spring 1984-89, Tamarack Prairie, Colorado. Years Grass/fb Burn Sandsage Combined 1984 1985 1986 1987 1988 1989 0.256 0.134 0.232 0.208 0.589 0.527 0.856 0.313 0.358 0.526 0.836 0.753 0.372 0.162 0.256 0.258 0.627 0.577 Cr ass y fb 0.253 0.295 0.301 0.224 0.587 0.571 during Control Sandsage CombineG 0.814 0.687 0.643 0.847 1.045 1.052 0.334 0.355 0.368 0.309 0.622 0.628 I Values 1984-89 1988-89 0.78 1.10 1.18 0.51 0.79 Table 4. Mean height-density (dm) within Burn 3-84 and controls spring 1984-89, Tamarack Prairie, Colorado. during Years Grass/fb Burn Sandsage Combined Grass/fb Control Sandsage Combined 1984a 1985 1986 1987 1988 1989 0.222 0.021 0.106 0.077 0.466 0.647 0.827 0.121 0.356 0.286 1.215 1.435 0.493 0.047 0.201 0.157 0.831 1.159 0.183 0.191 0.200 0.216 0.625 0.934 0.935 0.797 1.044 0.688 1.494 1.888 0.531 0.503 0.629 0.424 1.059 1.548 I Values 1984-89 1988-89 2.13 0.21 apretreatment. 1.44 0.44 1.21 0.27 �Table 5. Colorado. Mean height-density (dm) within 1985 burns and controls Burn Year 3 2 during spring 1985·89, Tomarack Prairie, Control s 2 3 ~ GRASS' FORB 1985a 1986 1987 1988 1989 0.507 0.138 0.419 0.780 1.081 0.180 0.053 0.244 0.667 0.850 0.381 0.119 0.472 1.028 1.297 0.379 0.110 0.408 0.877 1.142 0.374 0.325 0.322 0.511 0.774 0.346 0.280 0.376 0.775 1.220 0.158 0.180 0.156 0.443 0.771 0.323 0.277 0.325 0.6';" 1.025 0.872 0.828 0.925 1.070 1.242 0.615 0.745 0.560 1.732 1.873 0.537 0.767 0.648 1.253 1.844 0.627 0.771 0.670 1.317 , .765 0.444 0.391 0.383 0.581 0.844 0.369 0.335 0.393 0.859 1.332 0.323 0.465 0.411 0.878 1.609 0.380 0.382 0.394 0.782 1.254 SANDSAGE 1985a 1986 1987 1988 1989 1.008 0.417 0.523 0.938 1.313 0.679 0.342 0.591 1.167 1.582 0.642 0.438 0.769 1.144 1.385 0.744 0.388 0.672 1.125 1.446 COMBINED 1985a 1986 1987 1988 1989 0.565 0.142 0.425 0.786 1.109 0.407 0.130 0.476 1.037 1.340 0.302 0.088 0.330 0.766 1.017 VALUE 1985·89 Grass-forb Cootlined apretreatment. 0.28 1.22 1988·89 0.27 3.15 0.429 0.124 0.426 0.899 1.196 �136 Table 6. Colorado. Mean height·density (drn)within 1986 burns and controls during spring 1985'89, Tamarack Prairie, Burn Year 3 2 Control g 2 3 ~ GRASS, FORB 1985a 1986a 1987 1988 1989 0.326 0.304 0.120 0.543 0.723 0.314 0.337 0.437 1.359 1.159 0.259 0.256 0.202 0.824 1.019 0.292 0.290 0.226 0.855 0.963 0.294 0.277 0.234 0.387 0.794 0.316 0.312 0.404 0.858 1.141 0.233 0.213 0.269 0.644 1.074 0.275 0.265 0.289 0.600 0.983 0.829 0.756 0.885 1.265 1.353 0.417 0.300 0.833 1.667 1.250 0.618 0.690 0.671 1.197 1.810 0.682 0.693 0.750 1.237 1.650 0.345 0.342 0.325 0.494 0.886 0.317 0.331 0.413 0.873 1.145 0.298 0.323 0.357 0.743 1.304 0.320 0.332 0.357 0.679 1.116 SA~DSAGE 1985 1986 1987 1988 1989 0.621 0.838 0.169 0.904 1.047 0.375 0.500 0.250 1.000 0.395 0.650 0.250 1.194 0.857 0.566 0.793 0.189 0.945 1.007 C~BI~ED 1985 1986 1987 1988 1989 0.421 0.470 0.127 0.616 0.815 0.315 0.339 0.434 1.355 1. 159 0.272 0.281 0.204 0.834 1.008 F VALUE 1985·89 Grass'forb Conbined 0.51 6.88b 1988·89 2.~ 10. a1985 and 1986 were both pretreatment years. be. < 0.050. 0.335 0.367 0.224 0.863 0.969 �Table 7. treatment (X) , and frequency of occurrence Crown cover (0.01-m2), species c~sition and control transects on Tamarack Prairie burn 1-84, Surmer 1989. Treatment Vegetation Crown cover COOll· of vegetation wi th in Corit r ~ l Freq. / occur. Compo Freq./ occur. 801.0 1112.5 201.0 582.0 141.0 9.0 1.5 23.83 33.10 5.98 17.32 4.20 0.27 0.04 100.00 100.00 88.89 100.00 57.78 4.1.,4 4.1.1. Crown cover Bare ground Dead vegetation 796.5 1535.5 Bouteloua gracilis Stipa ~ Spgrobolus cr~ptandrus Calamovilfa longifolia Andropogon hallii Paspalum stramineum Agropyron smithii Aristida sp. Panicum virgatum ~ & Carex spp. 906.0 1000.0 261.5 517.5 197.0 25.75 28.43 7.43 14.71 5.60 97.78 100.00 93.33 97.78 48.89 2.5 3.0 65.5 0.07 0.09 1.86 4.44 2.22 40.00 35.0 1.04 28.89 372.0 10.63 82.22 125.0 3.72 57.78 Opuntia spp. Ambrosia ~ilostach~a Artemisia ludoviciana Tradescantia sp. Phlox andicola Evolvulus nuttalianus Lath~rus pollmQrpbus Penstomen spp. Psoralea tenuiflora Ph~salis subglabrata Theles~rma sp. HaploP2~s spinulosus Mentzelia nuda Erigeron spp. 19.5 18.0 2.0 82.0 4.0 9.0 5.0 0.55 0.51 0.06 2.33 0.11 0.26 0.14 28.89 20.00 2.22 51. 11 4.44 17.78 6.67 13.0 91.0 15.0 84.5 5.0 10.0 6.0 4.0 2.0 0.39 2.71 0.45 2.51 0.15 0.30 0.18 0.12 0.06 24.44 37.78 4.44 57.78 8.89 11. 11 2.22 8.89 2.22 3.0 2.5 0.09 0.07 2.22 4.44 1.0 2.0 0.01 0.06 2.22 2.22 14.5 0.5 6.0 1.5 0.43 0.01 0.18 0.04 15.56 4.44 4.44 4.44 Croton texensis ChenoPOdium album Plantago ~ Lepidium densiflorum Cryptantha sp. Eupborbia sp_ Amaranthus sp. Lesguerella sp. Eriogonum ~ ~sp. Con~za canadensis He lianthus sp. 6.5 24.5 0.5 6.5 2.0 0.5 2.0 0.5 0.18 0.70 0.01 0.18 0.06 0.01 0.06 0.01 8.89 55.56 2.22 17.78 6.67 2.22 4.44 2.22 9.5 40.5 3.5 17.5 8.0 3.0 1.0 0.28 1.20 0.10 0.52 0.24 0.09 0.03 17.78 55.56 8.89 13.33 2.22 6.67 2.22 2.0 0.5 14.0 0.5 0.06 0.01 0.42 0.01 4.44 2.22 15.56 2.22 Artemisia filifolia 705.0 1784.0 �188 Table 8. treatment Crown cover (0.01-mZ), species CompoSltlon (X) , and frequency of occurrence and control transects on TamaraCK Prairie burn 3-84, SLITIT1er1989. Treatment Vegetation Crown cover COIlll· of vegetation wi th i n Control Freq./ occur. Crown cover COIlll· Freq. / occur. 357.5 5n.0 147.5 401.0 189.0 150.5 79.0 13.5 8.86 24.08 11.35 9.04 4.74 0.81 70.0 100.0 100.0 100.0 40.0 20.0 13.5 8.0 0.81 0.48 15.0 10.0 Bare ground Dead vegetation Bouteloua gracilis ~ comata Sporobolus cryptandrus Calamovilta longitolia Andropogon hallii Paspalum stramineum Agropyron smithii Panicum virgatum Muhlenbergia sp. i(oleria cristata ~ & Carex spp. 486.0 529.0 190.5 426.0 115.5 169.5 69.0 19.5 1.5 15.0 2.0 3.5 35.0 12.02 26.88 7.29 10.69 4.35 1.23 0.09 0.95 0.13 0.22 2.21 95.0 100.0 100.0 100.0 60.0 50.0 5.0 15.0 5.0 15.0 ao.o 40.0 2.40 65.0 Artemisia tilifolia Opuntia spp. Ambrosia 2§ilostach~a Artemisia ludoviciana Tradescantia sp. Phlox andicola Evolvulus nuttalianus Lath~rus pol~rebus Penstomen spp. 359.0 22.5 12.5 9.0 15.5 2.5 16.5 2.0 22.65 1.42 0.79 0.57 0.98 0.16 1.04 0.13 95.0 50.0 10.0 15.0 35.0 15.0 45.0 10.0 457.5 24.0 25.5 18.0 20.0 27.48 1.44 1.53 1.08 1.20 100.0 45.0 20.0 10.0 30.0 6.0 7.0 3.0 0.36 0.42 0.18 15.0 20.0 10.0 Physalis subglabrata Theles~rma sp. Mentzelia nuda Erigeron spp. ~ leptochylla Asclepias s~ciosa 2.0 1.5 4.0 21.0 20.5 2.0 0.13 0.09 0.25 1.32 1.29 0.13 5.0 5.0 5.0 40.0 15.0 5.0 1.5 25.5 7.5 7.0 0.09 1.53 0.45 0.42 10.0 45.0 25.0 5.0 Croton texensis ChenoPOdium album Plantago ~ Lepidium densitlorum Cryptantha sp. Euchorbia sp. Amaranthus sp. Polanisia trachys~rma Lesguerella ludoviciana 3.0 11.5 2.0 1.0 7.5 15.0 6.0 1.5 0.19 0.73 0.13 0.06 0.47 0.95 0.38 0.09 15.0 45.0 15.0 5.0 30.0 55.0 15.0 5.0 8.0 5.0 1.5 0.5 0.48 0.30 0.09 0.03 35.0 40.0 15.0 5.0 5.0 0.5 0.30 0.03 25.0 5.0 0.5 0.03 5.0 �Table 9. Mean crown cover (0.01-m2) for selected species, species groups, and covers within burn and control samples during pretreatment (1984) and post-treatment (1984-89) intervals, burn 1-84, Tamarack Prairie, Colorado. Pre-tr 1984 Aug 1984 Jul 1985 Aug 1987 Jul 1989 362.4 257.7 44.9 185.7 28.7 213.7 102.9 16.3 3.1 117.3 124.8 310.2 86.5 75.4 197.3 47.7 245.8 75.8 40.8 4.1 386.6 7.5 116.5 103.3 58.5 73.3 16.5 89.9 84.0 12.5 15.9 458.5 301. 9 155.2 127.9 53.0 103.7 31. 9 136.3 76.7 15.4 6.0 260.1 400.2 193.6 213.7 55.9 110.6 42.1 153.3 78.6 27.4 9.2 170.2 328.1 510.3 187.0 34.4 194.8 21. 8 216.9 63.5 27.6 1.6 104.4 91. 7 325.1 183.2 36.9 191. 5 29.2 221.7 67.2 28.8 50.6 91. 3 233.9 92.6 125.7 18.4 95.6 9.7 105.8 49.5 15.9 2.4 231.4 601.4 136.3 151. 2 34.9 123.6 25.1 150.0 32.1 33.0 16.2 198.5 477.8 171. 2 237.7 43.0 124.4 30.1 156.4 23.0 51. 3 21.4 150.6 381. 3 Andropogon, Panicum vigatum, BURNED TRANSECTS Boute1oua gracilis Stipa comata Sporobolus crvptandrus Ca1amovilfa longifolia Andropogon hal1ii Warm season grassesa Artemisia filifolia Perennial forbs Annual forbs Bare ground Dead vegetation CONTROL TRANSECTS Bouteloua gracilis Stipa comata Sporobolus cryptandrus Calamovilfa longifolia Andropogon hallii Warm season grassesa Artemisia filifo1ia Perennial forbs Annual forbs Bare ground Dead vegetation alnc1udes Ca1amovi1fa, and Paspalum spp. �190 Table 10. Mean crown cover (0.01-m2) for selected species, species groups, and covers within burn and control samples during pretreatment (1984) and post-treatment (1984-89) intervals, burn 3-84, Tamarack Prairie, Colorado. Pre-tr 1984 Aug 1984 Jul 1985 Aug 1987 Jul 1989 166.4 132.7 110.0 97.6 17.7 128.0 242.4 102.1 2.6 202.9 121. 6 87.5 23.7 69.4 68.2 9.1 89.4 116.6 85.5 14.3 706.2 31.4 35.1 59.4 53.1 86.1 4.6 95.0 196.4 50.2 63.0 250.2 153.1 67.3 84.1 76.9 92.3 15.2 126.4 154.1 52.0 32.3 359.6 275.0 91.6 204.8 55.5 81. 5 33.1 131. 2 171. 1 52.3 22.8 233.7 131.2 169.9 130.4 120.7 15.6 155.7 224.4 61.4 1.6 301. 2 141. 9 93.6 87.1 71.0 72.0 9.4 90.6 293.4 43.4 9.9 189.2 337.0 25.7 51. 7 41. 8 61. 8 5.5 70.0 250.3 27.1 17.8 273.8 460.8 61. 8 137.7 109.2 63.2 17.8 91.1 193.0 37.3 12.7 265.6 320.0 70.9 192.8 90.9 72 .4 38.0 123.4 207.2 58.2 10.1 171.9 277.7 Andropogon, Panicum vigatum, BURNED TRANSECTS Bouteloua gracilis Stipa comata Sporobolus cryptandrus Calamovilfa longifolia Andropogon hal1ii Warm season grassesa Artemisia filifolia Perennial forbs Annual forbs Bare ground Dead vegetation 254.3 CONTROL TRANSECTS Boute1oua gracilis Stipa comata Sporobo1us cryptandrus Ca1amovi1fa longifo1ia Andropogon hal1ii Warm season grassesa Artemisia filifolia Perennial forbs Annual forbs Bare ground Dead vegetation alnc1udes Ca1amovilfa, and Paspalum spp. �300 250 '" EI 1-84 BURN ~ .~ I C\I or- , , I I 1-84 CONTROL 200 0• 0 W > 0 I , , I ,, ,, \ \ ,, \ 150 \ \ , , \ 0' \ U Z , , , 8--- -----8 ~ '-'" a: v- / \ \ / \ 100 / \ / ~ -, 0 a: U / I / <, " 50 I ..... <, ".' ...1' ...:.. , 3-84 BURN / \: 3- 84 CONTROL '. o PRE-84 POST-84 85 87 89 YEAR Fig. 6. Crown cover (O.Ol-m2) of needle-and-thread grass from early spring 1984 (pretreatment) through summer 1984-89 (posttreatment) within the 1-84 and 3-84 burn and control sites, Tamarack Prairie, Colorado. �192 800 c----, : , I '-" , , 700 E ,....I , , .\ /\ _I, 600 o• o ....., a: 500 > o 400 1-84 BURN 1-84 CONT. w (J z 300 ~ o a: (J 200 3-84 BURN 100 PRE-84 POST-84 85 87 89 YEAR Fig. 7. Crown cover (O.Ol-m2) of total warm season grasses from early spring 1984 (pretreatment) through summer 1984-89 (post-treatment) within the 1-84 and 3-84 burn and control sites, Tamarack Prairie, Colorado. �4.5 j /,/ /'/ GRASS /'/ /< 4 0 . ,/ "..... E "'C '-' 3.5 - 3 > I- Ie SAGE ~ /. // /'" 0 ~ 0 '/: 0: TOTAL ~ ~ (/) Z W ~ 2.5 ~ ~ C I I- J: -WJ: ~ ~ 2 0 ~ (!' ~ 1.5 1 0.5 o PRIV BURNS CONT RENOV REVEG VEGET ATION TYPE Fig. 8." Height-density (dm) of residual grass-forb, sandsage, and total vegetation within selected vegetation types, early spring 1989 tamarack Prairie, Colorado. �194 The amount of bare ground increased dramatically following fire and has since declined to near pretreatment levels. In contrast, dead vegetation, initially reduced by fire, had almost fully recovered by 1987. Minor recovery was noted from 1987 to 1989 although the total amount for all samples was lower in 1989. The current growth status of vegetation, determined by precipitation and time of sampling, can influence year to year variation. Revegetation and Renovation Treatments Ti11age-Reseeding.--Sampling of residual HDI within the 1985 revegetation strips yielded nearly the same HDI (4.38 dm) as recorded in 1988 (4.44 dm). This index of residual (primarily switchgrass) quality was far greater than for native range whether or not it was grazed or burned (Fig. 8). Crown cover within the revegetation 3trips was not sampled in 1989 although switchgrass and its standing residual probably continued to increase in dominance. Renovation of Interseeded Tracts.--Evaluation of vegetation changes continued in 1989 within an interseeded site (1981-82) that was partially renovated (disked, harrowed, treated with atrazine herbicide) in spring 1986. The HDI of residual grass-forb vegetation declined slightly from the previous year in both treatment and control transects (Table 11). Comparisons between treated and control transects from 1986 (pretreatment) to 1989 showed that grass-forb vegetation within the renovated site possessed greater HDI (f < 0.01). Sandsage was too sparse to be considered in evaluations. Table 11. Mean height-density (dm) of grass-forb, sandsage, and combined cover from pre- (1986) to post-treatment (1987-89) intervals between a tillage-herbicide and untreated control within a previously interseeded location, Tamarack Prairie, Colorado. Year Tillage-herbicide Control 1986 1987 1988 1989 Grass-forb 0.382 0.314 1.554 1.388 0.393 0.271 0.551 0.449 1986 1987 1988 1989 Sandsage 1.234 0.227 1.136 1.143 0.696 0.608 1.268 0.781 1986 1987 1988 1989 Combined 0.579 0.306 1.525 1.373 0.544 0.375 0.677 0.520 �Crown cover of combined bluestems and switchgrass (interseeded species) increased steadily on both control and tillage-herbicide renovation transects from 1985 (pretreatment) to 1989. However, rate of increase within the treated sites was markedly greater (f < 0.005, Table 12). The rate of crown cover increase from 1988 to 1989 was approximately the same on both (f > 0.25), providing evidence that most effects of renovation had already occurred. Table 12. Average crown cover/transect of selected species and species groups from pre- (1985) to post-treatment (1986-89) intervals within tillageherbicide renovation of an interseeded site and control, Tamarack Prairie, Colorado. Species/group 1985 1986 1987 1988 1989 13.7 11.3 17.6 1.5 24.2 12.4 5.4 0.6 36.3 13.8 6.4 1.2 39.8 11.2 6.8 1.6 47.1 13.8 9.9 2.6 16.4 10.7 17.1 2.2 16.6 10.6 16.8 1.7 22.1 10.2 19.8 3.4 24.6 8.1 20.4 1.7 33.9 Tilla~e-herbicide Andropo~on/Panicum Calamovilfa longifolia Bouteloua, Stipa, etc. Perennial forb Control Andropogon/Panicum Calamovilfa longifolia Bouteloua, Stipa, etc. Perennial forbs E Andropogon/Panicum Calamovilfa longifolia Bouteloua, Stipa, etc. Values 8.5 27.6 1.2 1985-89 28.1P 3.23 30.964 4f < 0.005. Prairie sandreed, a deep-rooted native, continued to show little change from pretreatment status. Renovation had severely reduced other, more shallowrooted, perennial grasses. These continued to increase within control transects at greater rates than where treated (Table 12). Numerous other previously interseeded (1981-82) tracts on the Tamarack Prairie were renovated by management personnel in 1986-87. Pretreatment data were lacking but the HDI of 10 sites were sampled in early spring 1989. Grass-forb vegetation, primarily switchgrass and bluestems, was the primary cover with an average HDI of 2.71 dm (Fig. 8) and a range among transects of 1.66-4.14 dm. �196 These renovation tracts all possessed better cover than the site used in previous evaluations. Their HDI was less than that for the revegetation seeded in 1985 (Fig. 8). Strip Spraying of Sandsage.--Little change from the previous year occurred in HDI of residual vegetation within the 1985 sandsage spray site (Table 13). The HDI of grass-forb vegetation increased slightly, whereas that of dea~ sagebrush declined. Pretreatment data are lacking so changes in grass-forb HDI caused by spraying remain unknown. A 99+% kill of sandsage had been previously recorded. Although residual sandsage has slowly deteriorated, it still provides considerable cover. Sandsage was the visual obstruction in 37.2% of the 1987 samples, contrasted to 24.1% in 1988, and 22.7% in 1989. A portion of the sprayed site had been burned (prescribed) in May 1986 which removed all residual sagebrush. Grass-forb HDI was suppressed during the 1st post-treatment growing season, but recovered dramatically during the 2nd year under favorable precipitation (Table 13). Early spring 1989 HDI of grass-forb was slightly less than during the previous year indicating less favorable growing conditions in 1988 than in 1987. However, the data showed a high probability that fire enhanced HDI when compared with HDI trends of the sprayed site. Table 13. Mean height-density (dm) within the 1985 sandsage spray site during 1986 and 1987 post-treatment intervals and preburn (1986) to post-burn (1987-89) intervals within a portion burned in 1986, Tamarack Prairie, Colorado. Years li Transects Grass-forb 1985 SANDSAGE 1986 1987 1988 1989 SANDSAGE 1986 1987 1988 1989 4 4 4 4 Combined 0.879 0.800 1.127 0.960 0.468 0.469 0.737 0.740 0.713 0.333 1.250 0.404 0.129 1.133 0.911 SPRAY SITE 0.246 0.272 0.613 0.675 2 11 11 11 Sandsage SPRAY - 1986 BURN 0.279 0.122 1.131 0.911 Vegetation crown cover within the 1985 spray site, sampled in late May 1989, showed little change from previous years that could not be attributed to extremely dry early spring weather (Table 14). Annuals and perennials, that make major growth in early spring (e.g., Bromus, Stipa, Lathyrus, Allium, Cymopterus, Phlox), were less abundant or lacking in 1989 samples whereas the �Table 14. Crown random transects intervals within Tamarack Prairie, cover (point frame) of vegetation and ground cover within during pre-(1985) and post-treatment (1986-89) spring the June 1985 herbicide-treated sandsage spray tract, Colorado. Vegetation/cover Bare ground Dead vegetation Perennial grass Bouteloua gracilis Stipa comata Sporobolus cryptandrus Calamovilfa longifolia Other perennial grasses Annual grass Bromus tectorum Festuca sp. Artemisia filifolia (alive) A. filifolia (dead) Opuntia & Echinocereus spp. Perennial forbs Ambrosia & Artemisia spp. Tradescantia occidentalis Lathyrus polymorphus Psoralea tenuiflora Evolvulus nuttalianus Phlox andicola Allium textile Mentzelia nuda Leucocrinum montanum Penstemon angustifolius Thelesperma megapotimicum Cymopteris montanus Abronia fragrans Erigeron sp. Annual forbs Croton texensis Chenopodium ilhYm Pepidium & Lesguerella sp. Cryptanthia sp. Tragopogan sp. Plantago purshii Salsola kali Conyza canadensis Lactuca sp. Unid. forbs Pretreatment 1985 Post-treatment 1987 1988 1986 11 1989 402 1,425 529 1,324 536 1,083 387 990 472 1,207 142 194 34 51 4 148 510 46 65 15 312 425 106 53 19 307 683 161 120 15 311 563 108 124 15 70 117 4 116 7 38 10 436 112 1 259 o o 4 287 210 201 44 50 62 83 75 22 123 7 17 121 12 5 18 114 55 6 4 2 1 9 77 1 6 1 1 1 6 1 1 1 8 1 6 45 2 8 12 1 2 2 1 1 2 1 1 3 24 3 1 4 1 1 1 4 3 2 2 2 1 2 1 3 1 1 1 1 �198 amount of bare ground and dead vegetation increased (Table 14). Dominant grasses continued as in preceding years. Four live sage plants were tallied in 1989 showing recovery had ~egun for that species. Mentzelia and Thelosperma were also recorded as new post-treatment species. Monitoring of Greater-Prairie Chickens All but one of the poncho-mounted, solar-powered transmitters worked moderately well when placed on 12 greater prairie-chickens (6 males, 6 hens) trapped near the Tamarack Prairie in early April 1989. Eight other male prairie-chickens and one male sharp-tailed grouse (X. phasianellus) were trapped, banded, and released during trapping operations. Monitoring revealed the males remained near their respective leks, but their display activity was markedly impacted. Mike Schroeder (pers. commun.) reported this was typical unless males were radiomarked early in the year and had time to adjust. One male was found dead, [evidence indicated predation by a great-horned owl (Bubo virginianus)] in mid-April, and the transmitter was placed on a hen (total = 7). Hen 860 was trapped at Lek 1 (Fig. 9) as an adult on 2 April 1989. Early to mid-April movements were up to 4 mi. (6.4 km) northeast, however, she reduced movements in mid April and was routinely found in section 21, T10 N, R 49 W northeast of Lek 9 on the Tamarack Prairie (Fig. 9). She nested under a dead sagebrush plant on a hill near the center of Section 21 and began incubation in early May. She had nearly completed incubation on 30 or 31 May when killed by a coyote and buried (uneaten) about 100 m to the south. Size of the consumed clutch could not be determined. Hen 890 was trapped at Lek 1 as an adult on 2 April 1989. She usually remained north of Lek 1 and became stable primarily within the south one-half of Section 20, (T 10 N, R 48 W) on the Tamarack Prairie, usually not far from Lek 9 (Fig. 9). She nested under sagebrush 25 m south of the Tamarack Prairie boundary in the NWl/4, NWl/4 of Section 29 (T 10 N, R 48 W) and began incubation about 16-19 May. She was found away from the nest in early June and her coyote-predated nest was found on 12 June. Clutch size was unknown. She remained within Sections 20-21 on the Tamarack Prairie through the remainder of the summer and early fall. She was last found there on 12 October. Later attempts to find her were unsuccessful, possibly because her transmitter signal had become weak. Hen 921 was trapped, instrumented, and a blood sample was taken at Lek 9 on 3 April. She was flushed near Lek 9 on 6 April and flew well. Her signal was lost for a few days before she was found on 18 April about 4 miles (6.4 km) south-southwest in Section 8 (T 9 N, R 48 W). She remained near newly discovered Lek 14 through the remainder of April (Fig. 9). Her transmitter did not operate properly and contact was lost through May and early June except for 2 brief signals. These provided evidence she was still in the area, but her position could not be triangulated. She was flushed (without a brood) from a wheat strip in Section 8 on 19 June. That was the last time her transmitter signal was heard so her status through summer and fall remained unknown. Hen 132 was trapped and released at Lek 9 on 5 April. She moved 2-3 miles (3.2-4.8 km) east in early to mid April and became more sedentary, primarily �'Q"'1 11 t-'. IllOQ ...... t-'. .• n ..•. <;1 •• - n -.u ..-::::;; -z-: •• n "0 YY - n •• I YY 11 \0 (I) ~ • 13 I-' \Or-' 1-.1 00(1) . \0;0;"" TAMJ. RACK PR AIR IE III E. ~ »> '0 11 III •.... 11 •.... 111 890X n ~ •.... 211 n N CJl >c( o n rt t-'. III 18 23 *9 27 25 83~ X x 132 II) (I) I-' -1 ___ 21 1*2 ;0;"" (I) rt 86 0 X ~ (I) ::s ::s V 13 111 ~ 31 35 X 775 *1 C? 0) a 33 c( ~ 35 31 0 a: :f 2 1110 o ::s CJl 5 1 •.... 1 3 ::s 8 11 z c( (I) I-' III rt •.... o ::s 11 7 • *14 rt Q ~ CJ CJ 11 0 ..J a 12 w U) ROAD 46 o >- tt- Z ::J Z 0 ::J 0 v >- __ =c.=·= rt ffi t-'I ~ 11 III n ;0;"" 13 * X LEK· =-_ 0 NEST· L FGEND 1 SCALE t 3.2KM ==:l2ml. J~ 13 .'-D '.D �200 in the north one-half of Section 32 (T 10 N, R 48 W). Incubation had apparently begun on or before 12 May. The signal was lost from 25 May through 4 June. The transmitter and her remains (coyote predated) were found 4 m from the nest on 7 June. Predation bad apparently occurred at the time of signal loss as the 10 eggs, found under sandsage, were still intact, having been incubated 10-12 days. Hen 298 was trapped at Lek 1 on 3 April and remained near there, primarily to the north, through mid April. She was found in a sandsage swale in the southeast corner of Section 29 (T 10 N, R 48 W) in late April. An inconsistent signal obtained on 1 May gave evidence that she might be alive and nesting. The signal was lost in mid May and remains of an apparent coyote predation were recovered in early June. No evidence of a nest (shell fragments, etc.) was found so her nesting status and exact time of death are unknown. A severely chewed transmitter with a missing antenna was recovered 50 m southwest of the site later in summer. Hen 775 was trapped on 24 April at Lek 1 after the transmitter had been recovered from a predator-killed male. She remained near Lek 1 and began incubation about 20-22 May. She escaped when her nest of 10 eggs, located under sandsage 100 m northeast of Lek 1 in a sagebrush swale, was predated by a coyote on 1 June. The hen remained nearby through early summer, primarily east in Section 32. She was found and flushed on 1 August, but could not be located during subsequent searches there or elsewhere. Hen 835 was trapped on Lek 2 on 5 April. She moved about 2 miles (3.2 km) northeast and remained primarily in the NE1/4 of Section 36 (T 10 N, R 48 W). Incubation began about 8 May in the NWl/4 of the SWl/4 of Section 30 (T 10 N, R 47 W) 300 m into Sedgwick County. Her signal was last heard on 12 May, however, the nest site was not searched until early June in case she had covered the transmitter solar panels while incubating. The nest (6 eggs) was found intact under sandsage, where it had been abandoned. Extensive searches on the ground and with an airplane failed to yield a signal. Therefore, her survival status remained unknown. She was assumed lost to a predator. In summary, radio-marked hens gave no evidence of fidelity to the lek where captured, but nearly all nested near a lek. Hens moved extensively from lek to lek, reducing movement in mid- to late April. Nests and leks were widely dispersed and on private land. Two hens, trapped on Lek 1, moved and spent nearly all of their time near Lek 9 primarily on the Tamarack Prairie. One nested there and the other nested on private land within 25 m of the Tamarack Prairie boundary. Two other hens trapped on Lek 9, moved to nest near other leks. Oata (small sample sizes) failed to provide evidence that greater grass-forb residual cover quality on the Tamarack (Fig. 8) attracted nesting hens from adjacent private lands. All nest placements were associated with sandsage. Events deteriorated rapidly after mid-Mayas several hens and all nests (5, probably 6) were lost. By the end of the nesting season (early summer), 3 hens had been killed, 3 were confirmed alive, and the signal of one was lost. The area was flown in mid July, however, receiver problems hampered efforts to find birds. Visual obstruction sampling (HOI) was conducted at 5 nest sites and 10 proximal (~0:8 km) random locations. Sands age HOI - 2.11 dm) obstructed 56.7% of the readings at nest sites. At random sites sage obstructed 40.5% of the readings and averaged 1.75 dm. Grass-forb HOI averaged 0.33 dm at nest sites and 0.45 at random locations. Combined (grass-forb + sandsage) HOI's (& �201 averaged 1.34 dm at nests and 0.98 at random sites. Small sample sizes make these indices suspect (£ > 0.10), but provide evidence of nest site selection in relation to higher densities of better quality sandsage. Observations of nests sites supported this relationship. After one mortality in April, 3 radio-marked males were predator killed in May or early June and the transmitter from another was recovered at a site where no evidence of predation was found. This transmitter may have slipped off. Thus, one male (possibly 2) survived to mid summer. The male was not found during the fall, but weakening transmitter signals made monitoring difficult. Coyotes were suspected in all but the initial predation and in all nest predations. Primary predation coincided with rainfall and increased humidity apparently allowing them to stalk chickens by smell. During monitoring, males were not approached closely during the interval when they were killed and every effort was made to stay 50-100 m or more away from nesting hens. It is possible the radio-marked population received markedly greater direct and nesting predation than unmarked birds, but this remains unknown. Monitoring of leks in early spring 1990 will provide additional evidence, and assuming major popUlation declines have not occurred, radio-marking may be repeated. Sample sizes were inadequate to confirm a nest site-lek relationship if it occurred, however, most nesting and hen activities were near leks. Most radio-marked birds near Lek 9 resided on the Tamarack Prairie. It is possible that more use of the property would be made if more leks were present, however, few suitable lek sites exist there. Based on the possibility that use is related to presence of leks, several potential leks sites were mowed within the Tamarack Prairie in September 1989. These mowed sites should be maintained in future years to determine if more birds will occupy the Tamarack Prairie. Two additional small leks were found on private lands south of the Tamarack Prairie during monitoring efforts in late May and June. Both were found too late to obtain counts. One lek, contained 2 males based on track evidence after a rain. LITERATURE CITED Snyder, W. D. 1986~. Sandsage-bluestem prairie renovation. Job Progress Rep., Colorado Div. Wild1., Wildl. Res. Rep., Fed. Aid Proj. 01-03-045 (W-37R). Apr:475-498. 19862. Sandsage-bluestem prairie renovation. Job Progress Rep., Colorado Div. Wildl., Wildl. Res. Rep., Fed. Aid Proj. 01-03-045 (W-37R). Apr:499-525. 1987. Sandsage-bluestem prairie renovation. Job Progress Rep., Colorado Div. Wildl., Wi1d1. Res. Rep., Fed. Aid Proj. W-1S2-R. Apr:33l356. _______ . 1988. Sandsage-bluestem prairie renovation. Job Progress Rep., Co1orado'Div. Wildl., Wildl. Res. Rep., Fed. Aid Proj. W-152-R. In Press. �202 Prepared by -:1(1_~6} ~ Wuren D. Snyder Wildlife Researcher C �203 INTERIM FINAL REPORT State of: Colorado Project: W-152-R Work Plan: Job Title: 21 : Job Bird Research 4__ Accipiter Nest Site Selection and Foraging Behavior shinned Hawks in Mature Aspen and Conifer Habitats Period Covered: Author: Upland 01 January through 31 December of Sharp- 1989 Suzanne M. Joy Personnel: C. E. Braun, R. W. Hoffman, Colorado Division of Wildlife; R. T. Reynolds, U.S.D.A. Forest Service; R. L. Knight, S. M. Joy, Colorado State University ABSTRACT Feeding ecology of 11 sharp-shinned hawk (Accipiter striatus) pairs nesting in mature aspen, conifer, and mixed aspen-conifer habitats in western Colorado was investigated during 1988 and 1989. Sizes and taxa of prey were compared among nests and breeding stages, and between prey taxa. Relationships between diet composition and resource availability in habitats surrounding the nests were also compared. Small (~ = 2lg) birds comprised 91% of 513 prey items identified. Small mammals (~ = 4lg) made up the remainder of the diet. Unique plucking and feeding habits of individual pairs accounted for differences in total prey and avian prey numbers among nests. Over twice as many prey items were found during the nestling period at the majority of nests (67%) than during incubation or fledgling stages. Although birds were consumed more often than mammals during all breeding stages, mammalian prey frequency progressive~y increased from incubation through the fledgling stage. Numbers avian prey at the nest sites increased 164% from incubation to the nestling stage and declined 274% from nestling to the fledgling stage. Nearly 60% of the birds eaten during nestling and fledgling stages were young of t~e year. A shift in median bird prey weight from 17.4 g during incubation to . 12.1 g during the nestling period reflected the tendency of hawks to consume more young birds as the breeding season progressed. Hawks at nests dominated by aspen habitat (n - 5) consumed fewer mammals (6.8% of diet) than hawks at 1 nest surrounded by coniferous habitat (28.3% of diet). Conifer habitats appeared to have less foraging value compared to mature aspen types. Avian prey were consumed in proportion to their size availability and species composition in habitats surrounding nests, whereas certain taxa and size classes of mammals were preferentially preyed upon. A draft thesis incorporating the feeding ecology, nest site characteristics, and prey delivery rates of sharp-shinned hawks will be completed by 31 July 1990 in partial fulfillment of the requirements for a Master of Science. of Prepared by: Q;t ~'-' i1A '!tr S~z~ nne M. Joy Graduate Research Assistant Approved by: Wildlife Researcher ��205 JOB PROGRESS REPORT State of: Colorado Project: 'W-lS2-R Work Plan: 21 Job Title: Evaluation of Habitat Quality on Conservation Eastern Colorado Period Covered: Author: : Job Upland Bird Research 01 January S__ through 31 December Reserve Lands in 1989 Warren D. Snyder Personnel: C. E. Braun, J. J. Heinemann, D. D. Johnson, W. D. Snyder, Colorado Division of Wildlife T. E. Remington, and ABSTRACT Visual obstruction readings (VOR) , the primary index to grass-forb quality for wildlife, remained low (0.36 drn) in early spring 1989, but increased to 0.77 drn by mid summer within 140 Conservation Reserve Program (CRP) fields sampled in eastern Colorado. This overall sample included lOS fields randomly selected for sampling in 1988. Early spring VOR indices averaged 0.34 drn contrasted to 0.S6 drn in mid summer for this group (the group included 7 fields cost shared by the Division of Wildlife). The 7 fields were combined with 3S additional fields cost shared by the Division of Wildlife for evaluations initiated in 1989. 'JaR indices averaged O. Sl d.rnin early spring increasing to 1.13 drn in swnrner for this cost-shared sample. Fields containing switchgrass (Panicum virgatum), grass-alfalfa, and grass-sweet clover mixtures had the highest VOR indices in summer. Lack of precipitation hampered grass establishment in spring 1989, but above-average moisture in summer stimulated growth of previously established stands. Treatment of numerous fields by mowing or with herbicides for weed suppression continued. Canopy cover averaged 43% in summer 1989 of which seeded perennials comprised 33%; annual forbs and grasses comprised 67% of che total canopy cover. A relationship between percent land in the CRP and ring-necked pheasant (Phasianus colchicus) crowing count indices could not be detected. Use of a PATREC model to evaluate eastern Colorado pheasant range prior to, and during CRP, predicted increased pheasant density should occur. Lack of winter cover was a primary constraint. Similar models for scaled quail (Callipepla squamata) and northern bobwhite (Colinus virginianus) could not discern benefits of CRP to these species. ��207 EVALUATION OF HABITAT QUALITY ON CONSERVATION RESERVE LANDS IN EASTERN COLORADO Warren D. Snyder INTRODUCTION Personnel of the U.S. Fish and Wildlife Service, National Ecology Center (NEC) in Fort Collins, coordinating the national evaluation of the Conservation Reserve Program (CRP) for wildlife, did not request data for 1989. However, data were collected for evaluation of vegetation changes within CRP lands in Colorado as part of an ongoing study. The Division of Wildlife cost shared with many farmers in eastern Colorado attempting to promote establishment of vegetation that would be of greater value to wildlife within CRP fields. A random selection of these fields was included in the evaluation in 1989 to assess possible benefits. Limited PATREC (pattern recognition) modeling was also conducted to assist in estimating potential benefits of CRP to ringnecked pheasants. P. N. OBJECTIVES Determine distribution and quantity of Conservation Reserve Program land in eastern Colorado in relation to distribution of selected wildlife species, evaluate the quality of vegetation on these lands for selected wildlife species, measure response of selected wildlife species to the Conservation Reserve Program using existing annual surveys, and evaluate the impact of the Colorado Division of Wildlife's cost-share program on cover quality. SEGMENT OBJECTIVES 1. Conduct evaluations of randomly selected CRP fields within eastern Colorado as part of a regional and national assessment of the Conservation Reserve Program coordinated by the National Ecology Center (NEC) of the U.S. Fish and Wildlife Service. 2. Conduct intensive visual obstruction readings (VOR) in a stratified random sample of CRP fields and proximal controls. 3. Conduct intensive visual obstruction readings (VOR) in a sample of fields cost shared by the CDOW (for enhancement of cover quality) for comparison with CRP fields not cost-shared. 4. Conduct pre- and post-treatment assessments of a randomly selected sample of CR fields based on PATREC and HSI models for a selected sample of wildlife species. 5. Estimate response of selected wildlife population surveys. species to the CRP based on annual �208 6. Compare the distribution of CRP lands in eastern Colorado selected wildlife species. 7. Compile and analyze data and prepare annual progress to that of report. METHODS Methods used were described by Snyder (1989). Visual obstruct: ~n readings were based on the Kirsch method of sampling rather than the pr __ddure required by NEC personnel. The Colorado Division of Wildlife (CDOW) cost shared directly with farmers on numerous CRP fields in eastern Colorado to increase use of grass species possessing greater herbaceous cover quality for ring-necked pheasants and other ground-nesting wildlife. Seven of these fields were within the initial NEC sample of 104 fields monitored beginning in 1988. Thirty-six additional fields were randomly selected in February 1989 and landowners were contacted for access permission to monitor vegetation conditions. It was learned later that one of these fields had not been cost shared by the CDOW. Therefore, that field was included within the NEC sample bringing total fields not cost shared to 98 among 105 total NEC fields. Forty-two fields, cost shared by the CDOW, were monitored bringing the overall sample to 140. Efforts were coordinated with T. E. Remington, who conducted a companion study assessing use of CRP fields by avian wildlife. RESULTS AND DISCUSSION Environmental Conditions and Stand Establishment Early 1989 remained extremely dry throughout eastern Colorado and most of the winter wheat crop was either severely stunted or lost. However, considerable rainfall was received, starting in May, in southeastern Colorado and continued through most summer months (Table 1). Limited precipitation was received during mid-May in northeastern Colorado, but it remained dryer than southeastern Colorado until June. July was moderately dry at most locations (Table 1). The last significant rainfall in eastern Colorado :ccurred on 20 September and conditions remained extremely dry through October, November, and December at nearly all locations. A few inches of snow were received in midDecember but added little soil moisture. The distribution pattern of moisture in 1989 was similar to that in 1988 (Table 1), with Springfield in extreme southeastern Colorado receiving the greatest amount both years. Springfield and Greeley were the only stations exceeding long-term averages. Except in the eastern tier of counties, most sites received below average annual precipitation in 1989 and less than in 1988 (Table 1). Conditions for grass establishment on newly seeded CRP tracts were especially poor in early spring, however, some establishment of cool-season species was noted during the early summer. Weather conditions were more conducive to growth of previously established warm-season stands and excellent stands were noted by late summer in Baca County and other eastern tier locations. �Monthly Table 1. and annual precipitation Month Springfield lamar Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1989 1988 0.22 0.20 0.20 0.72 3.35 6.01 1.54 2.25 2.63 0.74 0.02 0.24 18.12 17.43 0.27 0.23 0.47 0.53 2.72 3.17 0.56 2.69 2.36 0.12 T 0.33 13.45 11.58 16.65 15.40 longterm R (in.) at 9 u.s. Weather Bureau locations in Eastern Colorado, 1989. limon Burlingtona Akron Greeley Holyoke 0.13 0.26 0.33 0.57 1.56 1.89 0.91 1.89 1.64 0.18 0.05 0.19 9.60 9.42 0.43 0.45 0.39 0.34 2.20 2.42 0.88 3.00 1.13 0.07 0.01 0.39 11.71 14.53 0.17 0.19 0.19 0.44 3.30 6.00 1.20 2.72 1.80 0.07 0.00 0.15 16.23 13.10 0.54 0.47 0.20 0.50 0.95 4.14 2.01 3.30 1.00 0.20 0.04 0.20 13.55 16.24 0.84 0.71 0.53 1.09 1.27 3.26 3.41 1.81 1.85 0.58 0.02 0.34 15.71 12.34 0.92 0.50 0.65 0.56 1.75 6.35 0.99 3.19 1.38 0.09 0.06 0.32 16.76 16.45 0.23 13.57 14.69 12.50 15.09 17.41 17.34 12.45 17.61 14.96 Rocky Ford Sterling 0.46 0.31 0.38 0.69 1.05 3.51 2.51 2.94 1.38 0.11 T -aHay through September data were missing and a weighted average between nearby stations was used. I'J o <o �210 An arbitrary rating of grass stand establishment within the 140 sampled CRP fields during summer 1989 revealed that perennial grass was rapidly gaining dominance (Table 2). The highest proportion of fields classed as none to poor occurred within strata 3 (57%) and 5 (41%). However, 61% of the tot~l fields contained grass stands rated fair to good in mid summer 1989. Table 2. Grass stand establishment summer 1989. Stratuma Fields 1 2 3 4 5 6 Percent 26 21 28 18 32 15 within 140 CRP fields, eastern Colorado, None Poor Fair Good 5 1 5 10 8 11 3 8 3 30.7 9 5 5 5 12 8 31.4 7 8 7 7.9 aSee Fig. 1 for locations 9 4 4 30.0 of strata. Five fields were not seeded to grass in 1988 due to failure of prerequisite sorghum cover crops. Among these, a cover crop and grass stand was attained in 1 field, cover crops were obtained on 2 others, and efforts on the other 2 remained unsuccessful. Extensive stands of field bindweed (Convolvulus arvensis) were a primary hindrance to cover crop establishment. One additional field in Kiowa County was replanted to a cover crop and later to grass apparently because of failure of the initial grass planting. Numerous fields in stratum 1 (primarily Phillips County) were seeded to smooth brome (Bromus inermus) in 1988 and subsequently treated with chlorsulfuron (Glean). However, the herbicide killed bromegrass, so nearly all fields were replanted in spring 1989 when extremely dry weather made grass establishment difficult. Five of these fields, subsequently reseeded in 1989, were included within the random sample under evaluation. Evaluation of Conservation Reserve Vegetation Quality Visual obstruction readings, the primary indices of herbaceous cover quality for nesting within CRP fields, were summarized for pre-greenup (early spring) and nesting (summer) intervals in 1989 (Table 3). During pre-greenup, the VOR index varied widely among strata (Fig. 1, Table 3) with highest indices occurring in northeastern Colorado. One reason was that most fields in strata 1 and 2 were seeded a year later than those in strata 3. Soil quality, grass species selection, and management practices used on the fields were also influential. Average indices were 0.299 dm (N = 98) for fields not cost shared, contrasted to 0.505 dm (N - 42) for CDOW cost-shared fields yielding an overall mean of 0.36 dm (N - 140) during the pre-greenup 1989 interval (Table 3). Most (29 of �211 42) CDOW cost-shared fields occurred within the eastern 1) which usually possessed high VOR indices. Therefore, conducted comparing VOR indices in 42 cost-shared fields CRP fields (tl - 46). There was no difference (f> 0.40) greenup data sets. tier of strata (Fig. an analysis was with non cost-shared between the 2 pre- Table 3. Visual obstruction readings (dm) within sampled Conservation Reserve fields in eastern Colorado ''.lringearly spring and mid-summer, 1989. tl Stratum fields INITIAL NEC RANDOM 1 SAMPLE 17 2 11 3 4 5 6 Total CDOW COST-SHARED COMBINED 1 2 3 4 5 6 COMPARISON NEG CDOW Spring 1989 Mean Summer Sum 1989 Mean 24 14 27 12 7.717 8.365 4.103 1.478 8.382 2.276 0.454 0.760 0.171 0.106 0.310 0.190 13 .052 12.115 10.617 8.740 12.127 7.141 0.768 1.101 0.442 0.624 0.449 0.595 105 32.321 0.342 63.792 0.564 FIELDS ADDED IN 1989 35 17.708 0.521 43.806 1.252 SAMPLES 13.232 15.205 5.391 3.767 9.995 2.439 0.509 0.724 0.193 0.209 0.312 0.174 26.266 26.892 16.405 14.516 14.603 8.816 1.014 1.281 0.586 0.806 0.456 0.588 50.029 0.360 107.598 0.769 60.229 47.432 0.615 1.129 NEC AND COST-SHARED 26 21 28 18 32 15 Total Sum 140 OF NON-COST SHARED AND COST SHARED FIELDS 98 29.320 0.299 42ab 20. 709 0.505 aInc1udes 7 fields from the 105 NEC random sample. b4l fields were sampled in spring and 42 in summer, 1989. Comparison of VOR indices for the NEC sample between 1988 and 1989 pre-greenup intervals revealed the index was slightly lower in 1989 (Table 4). Many CRP fields in 1988 still contained a standing (sorghum) cover crop into which grasses had not yet been seeded. This was probably the reason for the higher index in spring 1988. �212 Fig. 1. Strata for sampling conservation reserve fields in eastern Colorado, 1989. �213 Table 4. Average visual obstruction readings (dm) within NEC Conservation Reserve fields sampled during pre-greenup and nesting season intervals, eastern Colorado 1988-89. Pre-greenup 1988 1989 0.39 0.34 Nesting 0.20 0.56 Although weather conditions were extremely dry during spring 1989, abundant rains beginning in May (southeastern Colorado) and June (northeastern Colorado) dramatically enhanced growth of herbaceous vegetation within CRP fields (Table 1). Most fields, especially in southeastern Colorado, were treated with a contact herbicide to suppress annual forbs, however, frequent rains reduced the effectiveness of these efforts. As a consequence, many fields were mowed, primarily after nesting season sampling had been completed. Indices of VOR increased dramatically from early spring to nesting season in 1989 (Table 3) and were markedly above those obtained in 1988 (Table 4). VOR indices within 42 cost-shared fields averaged 1.129 dm compared with 0.615 dm for the remaining 98 fields in the NEC survey. Comparison of VOR indices from 42 cost-shared fields with those from the remaining 46 fields in the eastern tier of strata revealed that cost-shared fields possessed greater cover quality (f < 0.05, ~ - 2.19, df = 86). An attempt was made to derive a more accurate assessment of cost sharing by using a paired comparison analysis. One severely hailed CRP field was excluded. However, this analysis failed to show a marked difference (f > 0.05, ~ = 1.75. df - 40). Several factors including year seeded, stand establishment, soil type differences, and mowing and/or herbicide treatments, made it difficult to analyze the data by paired comparison. As grasses develop and dominate in future years, a more realistic evaluation can be obtained. Switchgrass and other tall warm-season grasses were the primary species in cost-shared fields. Comparison of nesting season VOR's by dominant cover showed these possessed higher indices than most other cover types (Table 5). Fields where alfalfa had been added to cool season grass stands [wheatgrasses (Agropyron spp.) and smooth brome] also yielded higher VOR indices than those containing single grass species. The CDOW provided free alfalfa seed to farmers. However, the U.S. Department of Agriculture, Soil Conservation Service was responsible for approving seed mixtures in CRP fields. They were reluctant to approve use of alfalfa because it has a relatively short life span in much of eastern Colorado. Other perennials apparently do not readily replace it when it dies and concern for possible erosion had priority over its wildlife value (H. Sprock, Soil Conserv. Serv., Greeley, pers. commun.). One field of tall wheatgrass (a. elongatum) in northwestern Weld County, attained dramatic growth in 1989, primarily because of abundant winter moisture in that location (Table 5). However, pure stands of other wheatgrass species, primarily within strata 5 and 6, possessed lower VOR indices. Four CRP fields �214 contained abundant sweet clover and had high VOR's during nesting season sampling. Since this was the 2nd year for this biennial, cover conditions will decline markedly in the future. Grama grasses (Bouteloua spp.) were dominant in most southeastern Colorado CRP fields and usually possessed poor to fair VOR indices (Table 5). Table 5. Visual obstruction readings (drn) in relation to dominant grass species within Conservation Reserve fields in summer 1989, eastern Colorado. Dominant species/covera Switchgrass Wheatgrass Tall wheatgrass Wheatgrass-alfalfa Smooth brome Smooth brome-alfalfa Sideoats grama Blue grama Sweet clover Warm season mixes No significant perennial ~ VOR Fields 13 43 1.579 0.425 4.625 1.023 0.872 2.413 0.505 0.044 2.372 0.767 0.581 140 0.769 13 25 1 6 7 1 25 2 4 grass Total/average aMany fields dominated annual forbs. by grasses contained large quantities of Cover quality (VOR) for nesting ring-necked pheasants was ranked based on data collected in past studies (Snyder 1984, 1988, Table 6). During pre-greenup 1989, 89 (64%) of 139 fields were rated extremely poor « 0.26 dm), 23 (16.5%) were poor (0.26-0.50 drn), 13 (9.3%) were fair (0.51-1.0 drn), 11 (7.9%) were moderate (1.1-2.0 drn), and 3 (2.2%) were good (> 2.0 drn). In comparison with data from the 1988, fewer fields occurred in extremely poor and good classes and more fields were rated poor to fair (Table 6). Considerable improvement in cover quality occurred by summer 1989. Fields rated extremely poor for pheasant nesting decreased to 32.9%, 24.3% were poor, 19.3% were fair, 14.3% were moderate, and 8.6% were rated as good. This was dramatically better than during the previous summer. Among fields sampled, 31 (22.1%) were outside pheasant range and another 48 (34.3%) were in range classed as remnant (Table 7). Twenty-nine (20.7%) were within moderate to high pheasant range (Snyder 1985~). �215 Table 6. Ranking of Conservation Reserve fields for nesting pheasants by VOR classification (Kirsch-dm) during pre-greenup and nesting intervals, eastern Colorado, 1988-89. N Sample <0.26 fields 0.26-0.50 0.51-1.0 1.1-2.0 >2.0 Total Pre-greenup NEC-1988 NEC-1989 76 69 10 18 7 10 5 5 6 2 104 104 All 89 fields 89 23 13 11 3 139 Nesting Season NEC-1988 NEC-1989 87 42 8 26 4 20 3 12 2 5 104 105 All 89 fields 46 34 27 20 12 140 Table 7. Ring-necked pheasant range site ranking of sampled Conservation Reserve fields, eastern Colorado 1989. Rank Absent Remnant Low Fair Moderate Totals to high NEC 29 (76 present) 36 22 11 7 105 Fields CDOW cost shared Totals 2 12 10 7 4 31 (109 present) 48 32 18 11 35 140 Canopy cover averaged 37.3% during pre-greenup 1989 contrasted to 27.4% during spring 1988. The highest density occurred in stratum 1 and was dominated by annual vegetation (Table 8). Canopy cover increased to 42.6% during the 1989 nesting season (compared to 24% in 1988) and perennial grasses comprised 34% of the total vegetation. Average vegetation height increased from 9.7 cm (3.8 in.) in summer 1988 to 17.7 cm (7.0 in.) in early spring 1989 and averaged 16.3 cm (6.4 in.) during summer 1989 (Table 8). Thus, growth in 1989 resulted in increased density, but not height; most of the increased density was attributed to perennial grasses. �216 Table 8. Canopy cover of total vegetation, perennial grasses, annual vegetation, and mean vegetation height within Conservation Reserve fields among strata during pre-greenup and nesting season intervals, eastern Colorado 1989. N fields Total vegetation 26 21 28 18 32 14 139 46.9 43.8 29.6 32.3 35.4 35.5 37.3 Nesting 1989 1 2 3 4 5 6 Total/mean 26 21 28 18 32 15 140 47.0 50.2 47.0 46.0 34.9 28.8 42.6 Quantity, Quality, and Security Stratum Pre-greenup 1 2 3 4 5 6 Total/mean Canol2l:cover Perennial grass ~%2 Annual vegetation Height (em) 7.2 7.1 6.1 10.7 11.4 9.9 8.7 39.7 36.7 23.5 21.6 24.0 25.6 28.6 20.8 27.2 14.1 11.7 16.5 15.0 17.7 15.6 15.8 11.4 20.9 13.3 11.5 14.5 31.4 34.4 35.6 25.1 21.6 17.3 28.1 18.9 20.5 13.4 16.4 12.7 18.4 16.3 1989 of Land Use Types Percentages of vegetation types were sampled by strata in early spring 1989 (Table 9). Rangeland was most abundant especially in strata 4 and 5. These data reflect land use in areas proximal to CRP fields, which, in turn, were formerly cropland. Percent rangeland would be much higher, especially in strata 4 and 5, if sampling was completely random. When small grains, standing stubble, and mulched stubble were combined, they totaled about 42% of the available land. Comparisons of standing and mulched stubble clearly demonstrate that most wheat stubble is left standing over winter in northeastern Colorado (strata 1 and 6) whereas little remains in southeastern Colorado. Some land classed as fallow was formerly wheat stubble tilled after harvest to provide volunteer wheat pasture for livestock through fall and winter. Corn was a minor crop in most sampled areas except in strata 1 and 2, whereas sorghums and millets were common in all areas. Millets, especially, were planted on lands set aside from other crops under the Federal Farm Program. Land in CRP ranged from 7.7% (stratum 1) to 23.3% (stratum 4). However, when rangeland was deleted, CRP increased from 9% (stratum 1) to 56.2% (stratum 4) of the cropland. It was evident that CRP, like sampling, was not distributed uniformly among croplands since CRP had not been allowed to exceed 25% of the eligible cropland per county by more than 2-3%. Among vegetation types (Table 9), row crops and millet were not considered nesting cover for wildlife although they undoubtedly received minor use by some species. Rangelands provide relatively secure nesting habitat for several passerines including horned larks (Eremophila alpestris), lark buntings (Calamospiza melanocorys), western meadowlarks (Sturnella neglecta), and grasshopper sparrows (Ammodramus savannarum). Because of low VOR's and location, rangelands seldom contribute significantly to pheasant production in eastern Colorado. Where rangelands contain sand sagebrush (Artemisia �217 filifolia) or other shrubby growth forms, they provide nesting cover for mourning doves (Zenaida macroura). marginal to fair Small grains, primarily winter wheat, were more common than CRP in all strata except 4 and 5 (Table 9, Fig. 1), and few pheasants occur within those strata. VOR indices of wheat growth through spring 1989 surpassed those of CRP fields by late April in most parts of eastern Colorado pheasant range (Fig. 2). However, early spring drought conditions throughout eastern Colorado severely stunted wheat growth. Its pheasant nesting value in 1989 was much lower than in most previous years (Snyder 1984). Table 9. Major vegetation spring 1989. Vegetation types 1 (%) among strata, 2 3 eastern Stratum 4 Colorado, 5 early 6 13.6 26.0 2l.l 58.6 5l. 7 22.7 27.8 3.8 4.8 6.1 0.3 l.6 7.3 4.5 Small grains 32.1 26.9 25.2 8.6 10.4 28.2 24.2 Stubble Standing Mulched 23.1 2.5 13.7 6.1 3.8 11.2 1.5 2.9 5.9 2.0 17.3 4.4 12.4 5.3 Conservation Reserve % of total % of cropland 7.7 9.0 9.1 12.3 19.2 24.4 23.3 56.2 20.4 42.2 13.3 17.3 14.0 19.5 Sorghum/millet 3.7 4.9 6.8 4.7 7.9 3.9 5.3 11.4 7.2 2.5 l.7 4.8 Beans/beets 0.8 0.5 Sunflowers 0.2 0.6 Alfalfa 0.7 0.2 Unfarmed 0.4 Rangeland Fallow Corn N samples 1,390 0.3 0.1 3.8 0.3 0.4 0.3 0.9 l.1 0.4 1,498 1,292 408 1,000 1,012 6,600 Nesting interval 1989 sampling of wheat fields in all strata but #6 (where nearly all fields had already been harvested) was done to obtain VOR, canopy cover, and height data for comparison with CRP fields (Table 10). In general, wheat fields were much more abundant than CRP fields in strata 1, 2, and 6 and wheat VOR indices were higher in all strata. VOR indices of maturing wheat were approximately one-half those obtained during June 1988 sampling. �218 3.5 3 2.5 E "'C I a: GREEN WHEAT 2 0 > 1.5 1 WHEA T STUBBLE 0.5 CRP MULCHED STUBBLE o 13 25 APR 7 19 31 MAY Fig. 2. Visual obstruction reading indices of dominant covers in eastern Colorado, spring 1989. nesting �219 Table 10. Nesting cover abundance-quality indices among strataa between maturing wheat and Conservation Reserve, eastern Colorado, summer 1989. Stratum 1 Variable % occurrence VOR index Canopy coverage ~ Ht.(dm) 2 3-4 Wheat Wheat CR Wheat CR 32.1 3.1 51. 7 5.5 7.7 1.0 47.0 1.9 26.9 3.5 55.8 5.7 9.1 1.3 50.2 2.1 22.4 1.7 43.6 3.9 5 CR Wheat CR 20.2 0.6 47.0 1.5 10.4 2.3 41.1 4.6 20.4 0.5 34.9 1.3 in stratum 6 prior to sampling aNearly all wheat fields were harvested and it was not included. Wheat stubble, left standing over winter, provides night roosting, feeding, loafing, and escape cover for pheasants. Its VOR quality is important in determining overwinter survival of pheasants in relation to avian predation and blizzards (Snyder 1985h). In spring it attracts nesting by pheasants and other wildlife, but it is extremely insecure because nearly all stubble is tilled prior to completion of nesting efforts (Snyder 1984). Standing wheat stubble was more prevalent than CRP within strata 1, 2 and 6 and possessed higher early spring VOR indices than CRP in all but stratum 2 (Table 11). An index of its relative importance among strata, obtained by multiplying the 2 variables, showed that it remained especially important in stratum 1 and was of little significance as pheasant nesting cover in southeastern Colorado (Table 11). A similar abundance versus quality index for CRP fields indicated they exceeded wheat stubble in importance in southeastern Colorado (strata 3, 4, and 5) but: we re less important in strata 1, 2, and 6. Table 11. Comparison of wheat stubble occurrence (% of vegetation VOR (dm) by stratum, eastern Colorado, early spring 1989. types) and Stratum Variable Wheat Stubble Occurrence, % VOR index Import. indexa Conservation Reserve Occurrence, % VOR index Import. index 1 2 3 4 5 6 23.1 1. 06 4.5 13.7 0.64 8.8 3.8 0.34 1.3 1.5 0.39 0.6 5.9 0.36 2.1 17.3 12.4 0.31 0.62 7.7 5.4 7.7 0.51 3.9 9.1 0.72 6.6 19.2 0.19 3.6 23.3 0.21 4.9 20.4 0.31 6.3 13.3 14.0 0.17 0.36 2.3 5.0 "DerLved by mul.tLpLyLng percent occurrence x the VOR index , �220 Timing of stubble tillage was monitored through April and May previously sampled route in stratum 1. Among fields standing had been tilled by 24 April, 75% by 8 May, 83% by 18 May, and Thus, as in previous years of study (Snyder 1984, 1988, 1989), were cultivated during the peak interval for establishment of pheasants. Influence 1989 along a on 12 April, 11% 97% by 1 June. most fields first nests by of CRP on Wildlife Pheasant crowing counts, conducted along established routes in eastern Colorado in May, provide one means of monitoring potential influences of the CRP on pheasant populations in eastern Colorado. Crowing counts are a product of previous year production and summer-to-early spring survival. They provide indices of spring breeding population levels. A preliminary review of available data indicated that most routes were within locations containing relatively low percentages of CRP (Table 12). Pheasant breeding populations in most east-central and northeastern Colorado routes remained relatively stable at suppressed levels (based on historic data). Within CRP, the sorghum cover crop and weedy seral stages of establishment, by providing brood and fall-winter survival combinations, would seemingly have the greatest impacts on pheasant populations and subsequent indices. The cover crop did not provide nesting cover to pheasants during the year it was planted (1986-87 in southeastern Colorado and 1987-88 in northeastern Colorado). Grass seeding operations during the second year of treatment left little nesting cover and annuals dominated the first year after seeding. Among 140 CRP fields, only 1 was seeded to perennial grass in 1986, 51 (36.4%) were seeded to begin growth in 1987, 84 (60%) were seeded to begin growth in 1988, and 4 were seeded in 1989 or later. Thus, most CRP fields provided extremely marginal nesting cover until 1989 when better cover conditions existed (Tables 3 and 4). Table 12. Ring-necked pheasant crowin~ count indices (~ calls/station) and the percentage of Conservation Reserve along established census routes , eastern Colorado 1986-89. Census route Stratl.n Alli1erst -Paol i Julesburg-Alli1erst Julesburg-Crook Holyoke-Fleming lJages-Haxtun Fleming-Leroy Eckley-Yl.IIl8 Lonestar-Akron Sterling-Proctor Ft. Morgan-Narrows Platner-Elba Ida lia- Joes Bonny Reservoir Burlington North Smokey Hill Lamar-Bristol Las Animas Two Buttes Konatz-Stonington 1 1 1 1 1 1 1 1 1 6 2 2 2 2 2 3 4 &5 3 3 County Phi IIips Sedgwick Sedgwick-Logan Phi IIips-Logan Phi IIips-Yl.IIl8 Logan Yl.IIl8 lJashington Logan Morgan lJashington Yl.IIl8 Yl.IIl8 Kit Carson Kit Carson Prowers Bent Baca Baca % CR 2.4 0 <1.0 3.3 5.3 7.7 3.3 16.3 <1.0 2.7 3.3 2.5 0.9 3.2 0.5 5.4 1.7 33.3 12.0 1986 8.8 4.1 6.2 1.3 11.5 16.0 7.6 9.3 Crowins count index 1988 1987 16.8 18.3 14.1 13.4 10.4 8.1 16.4 5.8 12.7 9.8 7.1 10.2 3.0 5.6 5.5 11.9 3.0 16.8 12.6 apercent CRP was determined using a 1 or 2 mi. wide strip bisected by the census route. 23.1 13.4 19.1 7.0 16.7 9.0 23.8 10.4 14.7 8.7 2.5 10.5 6.3 12.1 10.6 4.0 31.3 39.0 1989 12.5 15.4 18.3 9.2 7.8 15.7 14.5 8.7 7.2 6.1 2.7 6.3 2.9 2.9 21.0 19.2 �221 Conservation Reserve comprised approximately 12 and 33%, respectively, of the land bordering the Konantz-Stonington and Two Buttes Routes in Baca County (Table 12), Consistent breeding population increases were noted along these routes from 1986 through 1988. These increases may have been at least partially a product of the cover crops and early seral vegetation provided by CRP. If so, the increases were primarily the result of increased survival rather than of markedly enhanced reproduction. Pheasant crowing indices along the Baca County routes declined in spring 1989 (Table 12) even though good populations were present in fall 1988 and winter survival conditions were not severe. Recent data indicate reproduction there was poor in 1989 even though nesting cover conditions had improved. Pheasant crowing counts along much of the eastern edge of Colorado declined from 1988 to 1989 whether appreciable CRP was present or not (Table 12). Poor reproduction influenced by dry spring weather in 1988 was considered a primary factor causing the decline in the northeastern corner although influences to the south were less certain. Severe winter weather has not been a factor in winter survival in recent years although pheasants in many areas are thought to be stressed by lack of suitable winter cover. It is evident that if CRP is benefitting pheasant populations in eastern Colorado, crowing counts have not provided strong evidence of it. More years of data are needed, and even then, it must be recognized that crowing indices, because of inadequate replications, are not highly accurate. Nor are pheasant population trends necessarily consistent throughout eastern Colorado. Numerous mourning doves and passerines were observed nesting and using CRP fields primarily during the nesting season inventory. However, reference is made to companion studies by T. E. Remington, who is monitoring reproduction and populations of several avifauna using CRP fields in eastern Colorado. Evaluation of CRP Using PATREC Models A PATREC (pat~ern recognition) model (Russell et al. 1980) for evaluating pheasant habitat in the High Plains of eastern Colorado was developed earlier (Snyder 1983). Model testing in dryland wheat farming areas had strengthened confidence in its predictive accuracy. Therefore, it was used to predict general carrying capacity of tracts of land prior to and after implementation of CRP. Based on a random sample (19) of eRP fields within strata 1, 2, and 3, predicted pheasant population increases averaged 7.4 birds/l.6l km2 (1 mi2) or 81.6% (Table 13). Predicted carrying capacity during both pre and post-CRP implementation intervals was higher in northeastern than in southeastern Colorado. In 3 instances no marked increase was predicted because these sites already contained considerable ungrazed perennial grass. In other cases, increases of several hundred percent were predicted. The model also indicated that addition of vast areas of nesting cover would not markedly improve pheasant populations in locations where winter survival habitat was deficient. Weaknesses in the model were identified in the evaluation. However, it was believed to be effective in predicting general population changes affected by CRP. Pheasant densities were higher in eastern Colorado when the model was developed than at present. Therefore, the model may predict higher than actual density increases. �222 Table 13. Predicted pheasant carrying capacity (birds/km2) on random sites prior to and following establishment of CRP, eastern Colorado, 1989. Stratum N 1 2 3 4 Total/~ Pheasantsikm2 Prior to CRP During CRP Percent change 6 5 7 1 12.7 8.8 7.3 2.0 21.8 16.4 13.7 5.0 87.9 150.0 19 9.1 16.5 81.6 71.7 86.3 Similar PATREC models had been under development and testing for evaluating scaled quail and northern bobwhite habitats. However, preliminary testing of the scaled quail model, in sites containing both CRP and scaled quail range, indicated no pronounced change would occur, or if it occurred, the change would be temporary. This was because cropland associated with shrubby rangeland provides feeding sites and seral edges. Conversion to CRP can temporarily enhance the food base and provide excellent feeding cover, but as grasses dominate the site, the food base and seral edge areas, so critical to quail, can actually diminish. Nesting habitat, which CRP might provide, is not considered limiting, and essential shrubby life form habitats are not provided by CRP. The same scenario exists for northern bobwhite except that their habitat requirements are even more restrictive than those of scaled quail in eastern Colorado. LITERATURE CITED Russell, K. R., G. L. Williams, B. A. Hughes, and D. S. Walsworth. 1980. WILDMIS-A wildlife mitigation and management planning system demonstrated on oil shale development. Final Adminis. Rep., Colorado Coop. Wi1d1. Res. Unit., Colorado State Univ., Fort. Collins. 152pp. Snyder, W. D. 1983. Pheasant habitat assessment and the PATREC model. Page 146 in R. T. Dumke, R. B. Stiehl, and R. B. Kah1. editors. Perdix III Gray partridge and ring-necked pheasant workshop. Wisconsin Dep. Nat. Resour. and Univ. Wisconsin, Campbellsport. 1984. Ring-necked pheasant nesting ecology and wheat farming on the High Plains. J. Wild1. Manage. 48:878-888. 1985~. Management procedures for ring-necked Colorado Div. Wi1dl. Spec. Rep 59. 53pp. 1985Q. Colorado. pheasants Survival of radio-marked hen ring-necked Wi1dl. Manage. 49:1044-1050. J. in Colorado. pheasants in �1988. Evaluation of no-till wheat farming. Job Final Rep., Colorado Div. Wildl., Wildl. Res. Rep., Fed. Aid Proj. W-1S2-R. Apr:303-32S. 1989. Evaluation of habitat quality on conservation rese rv e lands in eastern Colorado., Colorado Div. Wildl., Wildl. Res. Rep., Fed. Aid Proj. W-1S2-R. Apr:22l-244. Prepared by Warren D. Snyder Wildlife Researcher ��225 JOB PROGRESS REPORT State of: Colorado Project: W-152-R Upland Bird Research Work Plan: 21 Job Title: Evaluation Pro ram Period Covered: Author: : Job _6_ of Wildlife Responses 01 January through 31 December to the Conservation Reserve 1989 Thomas E. Remin~ton Personnel: Clait E. Braun, Thomas E. Remington, Warren D. Snyder, David A. Wilson, Colorado Division of Wildlife ABSTRACT Breeding birds were counted along line transects within 39 Conservation Reserve Program (CRP) Fields throughout eastern Colorado. Densities of breeding birds were computed from counts using a Fourier series estimator. Twenty-four species of birds were observed using CRP fields, but few were common residents. Horned larks (Eremophila alpestris) occurred in 25 fields sampled at an average density of 11 ± 12 birds/10 hectares. Lark buntings (Calamospiza melanocorys) were present in 26 fields at an average density of 4.0 ± 4.7 birds/10 hectares. Meadowlarks (Sturnella neglecta) occupied 32 fields (density 1.4 ± 1.3 birds/10 hectares). Mourning doves (Zenaida macroura) were common but many probably went undetected because of their inconspicuous breeding behavior. They were found in just under half of the fields sampled at an average density of 1.2 ± 2.3 birds/lO hectares. Grasshopper and Cassin's sparrows (Ammodramus savannarum and Aimophila cassinii) were fairly common in fields with heavier cover. They were found in 18 and 10 fields at densities of 3.7 ± 8.4 and 0.8 ± 1.7 birds/lO hectares, respectively. Several breeding birds were found in only 1 or 2 fields including ring-necked pheasant (Phasianus colchicus), northern bobwhite (Cciliriusvir~iri.ianus), d i ckc Ls se L (Spiza americaria), 'killdeer (Charadrius vociferus), upland 'sandpiper (Bartramia lon~icauda), red-winged blackbird (A~elaius phoeniceus), and song sparrow (Melospiza melodia). Other birds observed were migrating (vesper sparrow (Pooecetes gramineusJ, house wren (Tro~lodytes aedonl) or nested in adjacent rangeland or shelterbelts (lark sparrow (Chondestes ~rammacusJ, northern oriole [Icterus galbulaJ, loggerhead shrike [Lanius ludovicianus], American robin [Turdus migratoriusJ, western kingbird [Tyrannus verticalus]). Seventy-nine bird nests and/or broods were found in 29 CRP fields by dragging a rope between 2 observers. Nesting species, in decreasing rank order, were lark bunting, mourning dove, horned lark, meadowlark, Cassin's sparrow, pheasant, grasshopper sparrow, red-winged blackbird, and greater prairie-chick~n (Tympanuchus cupido). Some species were under-represented because peak ~: nesting occurred before we searched (horned larks and meadowlarks), or because of their inconspicuous response to the rope drags (grasshopper sparrow). ��227 EVALUATION OF WILDLIFE RESPONSES TO THE CONSERVATION RESERVE PROGRAM Thomas E. Remington P. N. OBJECTIVES 1. Measure and compare avian use of CRP to use of alternative types (wheat and summer fallow). 2. Measure and compare nesting wheat and summer fallow. 3. Relate patterns characteristics success habitat of birds on CRP to success of avian use and nest success and surrounding land uses. in CRP fields on to cover SEGMENT OBJECTIVES 1. Measure and compare densities stubble, and CRP fields. 2. Measure and compare nesting success wheat stubble, and CRP fields. 3. Relate patterns characteristics 4. Capture and attach transmitters to 40 pheasant hens; periodically relocate to determine extent, timing, and type of use of CRP fields. s. Compile of birds breeding of birds nesting of avian use and nest success and surrounding land uses. and analyze in green wheat, data, and prepare progress wheat in green wheat, in CRP fields to cover reports. METHODS A subset of CRP fields randomly selected by the U.s. Fish and Wildlife Service (from the Universe of all CRP fields in eastern Colorado) was randomly chosen for study. The random sampling procedure was stratified to obtain equal samples of fields in each of 3 land-use settings which were thought important to bird use, abundance, or diversity. These were: 1) CRP fields within primarily agricultural areas; 2) CRP fields within predominately sand sagebush rangeland; and 3) CRP fields within predominately short grass rangeland. Permission to enter and measure bird abundance within these fields was obtained via letter, and usually by telephone, from landowners. CRP, and some green wheat, and wheat stubble fields were sampled within an hour of sunrise to count breeding birds. A 0.8 km long transect was established near the midpoint of each field with plastic flags. An observer walked along the transect line slowly watching and listening for birds. Birds observed were identified to species and the perpendicular distance from each bird to the line transect was measured by tape, or eventually using a ro1otape, to the nearest meter. Breeding bird density was estimated from perpendicular distance measures using a Fourier series estimator (Burnham et al. 1980, 1981). �228 Eight hectares within CRP fields were searched for nesting birds by dragging 30-meter long rope between 2 observers. The area around the point a bird flushed was searched intensively for a nest. It was not possible to repetitively sample individual :ields to determine nest success because of time constraints. a RESULTS AND DISCUSSION Twenty-four species of birds were observed along line transects within CRP fields, but relatively few of these were resident breeders (Table 1). Horned larks were the most abundant breeding bird while meadowlarks were the most ubiquitous, i.e., they occurred in the most fields (32 of 39). Lark buntings were second in abundance and ubiquity (number of fields they were present in). The relative importance of these species is indicative of the generally poor condition of the grass stand and cover within these fields. Grasshopper sparrows were relatively common, especially in fields with earlier sign-ups and better cover. Cassin's sparrows were common in fields, generally in the southeast, that were planted to native bunchgrasses. Mourning doves were fairly common in fields with low cover and open ground, but were probably under represented because of their tendency to display from telephone wires or from elevated perches near field edges. Dickcissels were observed while singing in only 2 fields where sweet clover was abundant. Vesper sparrows were frequently observed in late April and early May, but were not observed later and were presumed to be using CRP fields while migrating. Occasional use of CRP fields by species that nested elsewhere (in trees or shrubs) was noted. These species included lark sparrow, northern oriole, American robin, loggerhead shrike, and western kingbird. Nests and/or broods of 9 species were found during searches of 29 fields. These were lark bunting (29), mourning dove (12), horned lark (10), meadowlark (9), Cassin's sparrow (7), pheasant (7), grasshopper sparrow (2), red-winged blackbird (2), and prairie-chicken (1). The number of nests found for each species was not necessarily indicative of breeding density or effort. Horned larks and meadowlarks were probably under represented because most nest searching was conducted after the peak of nesting for these species. Nests of grasshopper sparrows were difficult to find because of their habit of either running off the nest prior to flushing or not flushing at all. Three pheasant nests and 4 pheasant broods were found in CRP fields. It seems likely that pheasant broods moved into, rather than were produced in, CRP fields since the quality of cover was more suitable as brood habitat than nesting habitat. Nest densities of mourning doves were more indicative of dove use of CRP fields than breeding density estimates from line transects. The birds breeding in CRP fields, at this point in the program, primarily represent habitat generalists rather than grassland species. Few line transects or nest searches were conducted in green wheat or wheat stubble this year to increase sample sizes in CRP fields. However it was apparent that these habitats are used for breeding by lark buntings, horned larks, meadowlarks, mourning doves, and perhaps grasshopper sparrows. These are also the species commonly using CRP fields. Thus, the benefits of this program to breeding birds is unclear. �229 Table 1. Birds observed, breeding density (birds/10 ha), and percentage of sampled Conservation fields in which birds occurred, eastern Colorado, 1989. Species Number Fieldsa Horned lark Lark bunting Grasshopper sp. Meadowlark Cassin's sp. Vesper sp. Mourning dove Red-winged blackbird Pheasant Western kingbird Dickcissel Song sparrow Mallard Northern bobwhite Lark sparrow Field sparrow House wren 236 l30 86 72 39 30 24 9 7 7 64 67 46 82 26 28 46 10 8 10 3 3 8 3 3 3 3 3 3 3 3 3 Ki.Ll.de e r Northern oriole American robin Loggerhead shrike Upland sandpiper apercentage 5 5 4 3 2 1 1 1 1 1 1 1 of sampled Density ~ SD 11.0 4.0 3.7 1.4 0.8 12.0 4.7 8.4 1.3 1.7 1.2 2.3 Conunents Bunch grass fields Seen during migration Probably breeding Tree grove in field Tree grove in field fields in which species occurred. Attempts to capture and radio-mark pheasant hens to quantify pheasant use of CRP fields, versus alternative cover types, for nesting and brood rearing were not successful. Additional trapping techniques will be attempted this winter. LITERATURE CITED Burnham, K. P., D. R. Anderson, and J. L. Laake. 1980. Estimation density from line transect sampling of biological populations. Wildl. Monogr. 72. 202 pp. _____ , , and . 1981. Line transect estimation of bird population density using a fourier series. Studies Avian Biol. 6:466-482. Prepared by~f Thomas E. Remington Wildlife Researcher of ��231 JOB PROGRESS State of: Colorado Project: W-152 -R Work Plan: 21 Job Title: Avifauna Period Covered: Author: Personnel: REPORT Upland Bird Research : Job _7_ Responses 01 January Cynthia to Grazing through 31 December 1989 P. Melcher C.E. Braun, K.M. Giesen, C.E. Poley, Colorado Division of Wildlife; Cynthia P. Melcher, Colorado State University ABSTRACT Long-term population data indicate that white-tailed ptarmigan (Lagopus leucurus) breeding densities have declined in Rocky Mountain National Park (RMNP). Examination of elk (Cervus elaphus) population estimates for the Park reveals a negative relationship between decreas~ng ptarmigan and increasing elk population trends. Willow (Salix spp.), an essential ptarmigan food, may be declining in areas that are more heavily browsed as the elk population increases. A pilot study was conducted from 12 May through 16 August 1989, to ascertain whether local levels of browsing by wild ungulates in alpine/krummholz areas (ptarmigan breeding habitat) were related to local differences in breeding bird densities. Four 17.44 - 22.24 ha study sites were selec~ed ~ear Trail Ridge Road (TRR) in RMNP on the basis of historically similar ptarmigan densities and similar amounts of krummholz canopy cover. Two 100 x SO m plots were selected at each site in willow dominant or codominant communities. Sixty m2 sample plots were randomly chos~n in each plot. Willow charact~ristics,and herbIvore pellet/chip frequencies were measured in the 480 sample plots, '.and breeding bird densities were measured throughout each st~dy, site. IJngula;e pe ll.et Zch Ip f'requency distributions indicated ,that·ungulate presence-was greater in both plots at the Sundance Basin (RCS) and Tombstone Ridge' (TSR) sites, and in one plot at the Gore Range Overlook (GTO) site. Willow characteristics that implicate'high levels of ungulate browsing were: high basal stem densities (including adventitious shoots), low live/unbrowsed terminal leader abundance, low bud abundance, and extremes (low and high) in height. One RCS plot, 2 TSR plots, and 1 GTO plot were characterized by heavily browsed willows. Ptarmigan counts were lowest at RCS and TSR. Avian species richness was greater at RCS and TSR. ��233 AVIFAUNA RESPONSES TO GRAZING Cynthia P. Melcher INTRODUCTION In Colorado, ptarmigan subsist on willow buds and leader tips from fall through spring (Braun 1969, Schmidt 1969, May and Braun 1972, May 1975, Hoffman and Braun 1975, Braun et a1. 1976, Giesen et al. 1980). Willard and Marr (1970) described how limiting resources and extreme climatic constraints can retard recovery of damaged vegetation in alpine tundra ecosystems. It is highly probable, therefore, that severe damage to willows in a1pine/krummho1z regions would result in a long term decline of ptarmigan densities. Ptarmigan in RMNP have been banded and monitored since 1966 (Braun and Giesen 1988). Census data illustrate the ptarmigan population has exhibited a precipitous and persistent population depression since the mid-1980's. Colorado Division of Wildlife researchers observed an inverse relationship between elk and ptarmigan population trends in the Park (Fig. 1). Historically, ptarmigan habitats (Braun 1969, Schmidt 1969, Braun et al. 1976, Giesen et al. 1980) and elk seasonal ranges (Natl. Park Servo 1975, Green 1982, Bear 1989) in RMNP have not overlapped significantly. In addition, researchers have presented evidence that willows were not preferred elk foods (Kufeld 1973, Hobbs 1979, Baker and Hobbs 1982) in RMNP. However, other researchers have shown that heavy browsing by ungulates has altered habitats in the Park (Ratcliff 1941, Packard 1947, Stevens 1971, Olmsted 1979, Stevens 1980), and at least one study (Olmsted 1979) describes the decline of a Salix species as a result of heavy browsing by elk. Loss of elk habitat and migration routes, predator elimination, and heavy hunting pressure adjacent to RMNP may be causing changes in elk habitat use patterns in tna Park. Researchers and observers have noted that increasing numbers of elk are using alpine/krummholz communities year-round (Bear 1989; C.E. Braun and K.M. Giesen, pers. commun.), and it may be that limiting supplies of preferred foods in those areas are encouraging elk to forage on willows. High elk pellet frequencies and heavily browsed or trampled willows appear to characterize areas in which ptarmigan densities have declined. P. N. OBJECTIVES This study is designed to 1) document avian species richness and breeding bird densities in alpine/krummholz areas, 2) compare ungulate pellet/chip frequency distributions among alpine/krummholz areas, 3) compare willow characteristics among alpine/krummholz areas, 4) evaluate the relationships between ptarmigan breeding densities, ptarmigan habitat/resource quality, and levels of ungulate browsing among alpine/krummholz areas, and 5) initiate preliminary monitoring for a long term study. �(v W .j" 4 ~-------------------------------------'0 '68 '72 '76 '80 '84 '88 Fig. 1. Trends in white-tailed ptarmigan breeding densities, elk population (RMNP total), and number of elk using Trail Ridge Road (TRR) areas in Rock y Mountain National Park during 1966 - 89. �235 SEGMENT OBJECTIVES 1. Review pertinent literature applicable to ptarmigan and elk ecology, avian census techniques, herbivore pellet surveys, vegetation measurement techniques, alpine ecosystems, and National Park Service Policy. 2. Establish four study areas near Trail Ridge Road in Rocky Mountain National Park. Select and permanently mark 2 100 x 50 m plots at each site, and randomly select 60 m2 sample plots within each plot. Permanently mark and identify all sample plots. 3. Conduct at least 8 avian census visits at each site: abundance and species richness for each site. 4. Sample herbivore pellet frequency distributions, willow characteristics, and percent canopy cover for all plant species within each plot. 5. Randomly select one half of each plot for elk exclosure exclosures. 6. Analyze data, prepare season. METHODS reports. Submit proposal AND DESCRIPTION calculate relative treatment, for subsequent build field OF STUDY AREAS Four study sites were selected near TRR in RMNP, one each at Medicine Bow Curve (MBC), GTO, RCS, and TSR (Figs. 2a and 2b). Approximate areal measures are: MBC - 22.24 ha, GTO - 17.44 ha, RCS - 19.86 ha, and TSR - 19.33 ha. Criteria used for study site selection were 1) historical presence of whitetailed ptarmigan, 2) presence of willow-dominated or willow co-dominated plant communities,,3) relatively equal proportions of similar habitat types, and 4) minimal visibility from TRR. Site boundaries were determined according to compass bearings and notable landmarks, and were plotted on topographic maps. Time constraints and snow depth precluded the possibility of grid-marking sites. Eight 100 x 50 m plots (2 / site) were selected for sampling willow characteristics and herbivore pellet/chip frequencies. The criteria used for choosing plots were 1) occurrence of a site representative community of willow/krummholz vegetation and 2) minimal visibility from TRR. Plot boundaries were permanently marked at 50-m intervals with 30 cm metal stakes. Stakes were sprayed with fluorescent orange paint for visibility. Thirty m2 sample plots were randomly selected from 2,209 possible grid-coordinates within each 50 x 50 m half of the plots (assuming that one 50 x SO m half would be assigned to elk exclosure treatment at the end of the first field season). Each of the 480 resulting m2 sample plots were permanently marked at their centers with 30-cm metal stakes. Stakes were sprayed with fluorescent orange paint for visibility and marked with tags bearing alpha-numeric ID codes, which identified sample plots by site, plot, and row/column coordinates; e.g., MBC-A-04-2l. �236 SCALE 1:24000 CONTOUR NATIONAL GEODETIC INTERVAL VERTICAL 40 FEET OATU~ OF 1929 Fig. 2a. Locations of study sites and 100 x 50 m plots (plot 1 = solid fill, plot 2 = hollow fill) at East Sundance Basin (ReS) and Tombstone Ridge (TSR), Rocky Mountain National Park. �237 SCALE 1:24000 o Fig. 2b. Locations of study sites and 100 x 50 m plots (plot 1 = sol id fill, plot 2 = hollow fill) at Gore Range Overlook (GTO) and Medicine Bow Curve (MBC), Rocky Mountain National Park. �238 Eight avian census visits were conducted at each of the 4 sites from 27 May through 10 July 1989. Spot mapping methods and standards (IntI. B~.rd Census Comm. 1970) were used to record all species present. I plotted avian locations on graph paper according to compass bearings, landmarks, and counted paces. Sites were visited in sequential order, with at least 3 days separating visits at anyone site. Censuses began between 0600 and 0700 MDT and lasted approximately 3.5 - 5 hours, weather permitting. Poor visibility (dense fog, snow) and extreme wind yielded unreliable results; subsequently, I did not conduct census visits on such days. Ptarmigan were censused, regardless of weather, by using tape-recorded playbacks of ptarmigan vocalizations (Braun et al. 1973) and by tracking birds in fresh snow. Each avian census visit/site was recorded as one sample estimate relative densities of nesting species, species number/species using alpine/krummholz sites for foraging were marked with unique combinations of plastic colored allowed identification of individual birds and absolute (8 samples/site) to richness, and only. All ptarmigan leg bands, which ptarmigan counts. Vegetation and herbivore pellet sampling began 27 May and was completed on 3 August 1989. A l-m2 quadrat frame was used to define sample plot boundaries. The center of the quadrat frame was placed at the sample plot marker, with quadrat frame edges paralleling the 100 x 50 m plot markers. Vegetation sampling included visual estimates of plant species composition (percent canopy cover for each species/m2) within each sample plot and 13 different willow shrub measurements for those sample plots containing willow (Appendix A). Characteristics of prostrate (mat) willow species were not measured, but their canopy cover was recorded. Pellet sampling included identifying and recording occurrence of all herbivore pellets and chips within each sample plot (Appendix B). All pellets were removed from sample plots. Plant species ~anopy cover, willow characteristics, and pellet data were summarized and analyzed with Statistical Analysis Software (SAS). Chi-square frequency analysis was used to test homogeneity of herbivore pellet distributions among plots and sites. Summary statistics were used to describe willow characteristics and canopy cover for all plant species among plots. Because willow data were not normally distributed and have unequal variances among samples, further analysis to test for statistically significant differences in willow characteristics among sites will require data transformations or non-parametric tests. In September, the National Park Service decided to disallow the proposed elk exclosure experiment. Subsequently, all data for each 50 x 50 m plot (1/2 of 100 x 50 m) were pooled so that plots A and B are plot 1, and plots C and D are plot 2, for all study sites. �239 RESULTS Herbivore Pellet Survey Results Ptarmigan pellet and ungulate pellet/chip frequency distributions (Figs. 3 and 4) were significantly different from predicted frequency distributions (chi-square values were 35.428 and 209.636, respectively: (f < 0.0001 for both values). High ptarmigan pellet frequencies in MBG plot 1 and low ptarmigan pellet frequencies in both TSR plots contributed most to the overall chi-square value for ptarmigan pellet frequencies. Low ungulate pellet frequencies in both MBG plots and GTO plot 1 versus high ungulate pellet frequencies in both TSR and RGS plots contributed heavily to the overall chi-square value for ungulate pellet frequencies. Avian Census Results Avian census results varied by site (Table 1). Absolute counts of ptarmigan breeding pairs and single males (territorial and non-territorial) were higher Table 1. Ptarmigan Bird census results, counts are absolute. Spring 1989, Rocky Mountain Mean breeding Speciesa MBG WTPT WGSP WAPI HOLA LISP WIWA YRWA ROW'R MBBId AMROd ROFId PISId NOFLd +lb, 8.75 8.00 4.00 0 0 0.5c 0 2 2 10+ 5+ 0 3.5 +0.5c (3.99) (1.77) (1.60) GTO 3.66 -o.si18.91 (2.98) 8.08 (1.19) 3.81 (1.46) 0 0 0 0 1 2 0 10+ 0 pairs/site National Park. (SD) , n - 6 RGS TSR 0.55 +0.55c 22.20 (5.15) 7.60 (0.83) 3.19 (0.64) 1. 57 (0.53) 2.54 (1.11) 0 0 2 2 1 0 1 0.56 +0.5.6b 25.84 (7.51) 5.40 (0.99) 3.12 (1. 58) 0 0.85 (0.71) 0.68 (0.55) 0.80b (0.49) 3 4 0 0 0 aWTPT - white-tailed ptarmigan, WGSP - white-crowned sparrow, WAPI water pipit, HOLA - horned lark, LISP - Lincoln's sparrow, WIWA - Wilson's warbler, YRWA - yellow-rumped warbler, ROW'R - rock wren, MBBI - mountain bluebird, AMRO - American robin, ROFI - rosy finch, PISI - pine siskin, NOFL ~ northern flicker. bSingle territorial male. CSingle non-territorial male. dSpecies (no. pairs observed simultaneously) using site for foraging only. �240 60 CJ) W ....J 50 a. ~ « 40 CHI-SQUARE 35.43 0 CD P < 0.0001 (/) <, 30 >- o z 20 w ::J 0 w 10 a: u, ,0 1 2 MBC 1 2 1 GTO 2 1 RCS 2 TSR EXP Fig. 3. White-tailed ptarmigan pel let presence/60 l-m2 sample plots, expected frequency of ptarmigan pellet presence/60 l-m2 sample plots, and chi-square test for homogeneity of ptarmigan pel let distributions among plots. 60 CJ) w ...J 50 a. ~ ~~~-. CHI-SQUARE 209.64 P < 0.0001 :"., -, " "' '", ' ',,~ "' . "J « 40 (/) 0 CD <, ~~ 30 >- o ~~ ::J ~~ ~~ z 20 w 0 W 10 0: u, 0 ~~ 1 2 MBC 2 1 GTO 1 2 RCS 1 2 TSR Fig. 4. Ungulate pellet presence/60 l-m2 sample plots, expected frequency of ungulate pellet presence/60 l-m2 sample plots, and chi-square test for homogeneity of ungulate pellet distributions among plots. EXP �241 at MBC and GTO sites, and white-crowned sparrow (Zonotrichia leucophrys) densities were highest at RCS and TSR sites. Water pipit (Anthus ~libescens) and horned lark (Eremophila alpestris) densities were less variable among sites. Other species suspected of using sites for nesting were Wilson's warbler (Wilsonia pusilla), yellow-rumped warbler (Dendroica coronata), and Lincoln's sparrow (Melospiza lincolnii). These species were present at RCS and TSR but not at MBC or GTO. However, Wilson's warblers and Lincoln's sparrows were frequently heard just west of GTO, in willow stands that had more canopy cover (possibly due to greater moisture availability) than those within the study site. Yellow-rumped warblers were occasionally observed at MEC, but there was no evidence they nested at the site. A territorial male rock wren (Salpinctes obsoletus) was also recorded at TSR; neither female nor nest was located, however. More species were observed using MEC and RCS sites for just foraging than were observed using GTO and TSR for just foraging. Overall nesting species richness and breeding bird abundance was greatest at TSR and RCS. Vegetation Survey Results Percent canopy cover estimates were based on 60 l-m2 samples within each plot (Fig. 5). Overall, there was more willow canopy cover in MEC and GTO plots, and more conifer canopy cover in RCS and TSR plots. Mat willow was found in MBC plots, but not in other plots. Significant stands of mat willow were noted at GTO, but plot boundaries did not capture these stands. Mat willow was not observed at either RCS or TSR sites. Mean heights for all sampled willows were greater in both TSR plots, GTO plot 2, and RCS plot 1 (Fig. 6). However, standard errors for willow height were greater at TSR and RCS. When mean willow heights were calculated without including willows that grew among or adjacent to conifer plants, mean heights were reduced by 30 - 50% at TSR, and increased in plot I at RCS, in both plots at MBC, and in plot 2 at GTO. Willow bud abundances / 0.01 m2 were highest in both MEC plots, GTO plot 1, and TSR plot 2 (Fig. 7). When mean bud abundances were calculated without including willows that grew among or adjacent to conifer plants, mean bud abundances were higher in MEC plot 1, RCS plot 2, and both TSR plots: the same plots had lower mean willow heights when not growing in association with conifer plants. Basal stem abundance/0.25 m2 was greatest in RCS plots, and lowest in MBC plots (Table 2). Overall, live/unbrowsed leader abundance/O.Ol m2 was greater at MEC and TSR sites, although abundance was variable among the 4 plots. DISCUSSION Herbivore Pellet Survey Results Ungulate pellet/chip frequencies were higher (f < 0.0001) than predicted frequencies at RCS and TSR. Although occurrence of pellets/chips does not prove that elk have been foraging at those sites, it is an indication indication that elk are using alpine/krummholz habitats at RCS and TSR significantly more than alpine/krummholz habitats at GTO or MEC. �242 o o ,... o CO o U) o C\J C\I t- a: en ,... C\I en o a: ,... C\J o t- ,...G ,... o ~3J\O~ AdON\f~ .lN3~!::I3d en - -c..o ""a.. Q) a.. o - > o o >c.. o c ""c c o Q) a.. Q) ~ Q. t'J') u, �243 50 I ~ o ALL WILLOWS WILLOWS WITHOUT CONIFER ASSCCIA TION 40 - I ; E 30 o I- a- 20 W ::J: 10 1 TSR 2 Fig. 6. Mean heights and standard error bars for all willows and for those willows not associated with conifer species. 80 ~ N fI21J ALL WILLOWS WILLOWS W /0 CONIFER ASSOC. 60 ,...E o o 40 <, (/) c ::J 20 CO 1 MBC 2 1 GTO 2 1 RCS 2 1. TSR Fig. 7. Mea~ bud densities/O.Ol m2 and standard error bars for all willows and for willows not associated with conifer species. 2 �244 Table 2. leaders. Abundance of willow basal stems and live/unbrowsed Character Plot Measurement basis willow terminal ~ SE 8.33 9.58 18.40 13 .46 23.65 23.22 15.33 12.61 2.09 1. 53 2.52 1. 95 2.38 4.06 4.04 1. 86 10.27 6.00 10.53 6.61 5.32 5.85 5.00 9.93 1.24 0.90 1. 38 0.78 0.82 1. 20 0.90 1.11 ,., MBC MBC GTO GTO RCS RCS TSR TSR MBC MBC GTO GTO RCS RCS TSR TSR 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 Vegetation Basal Stems " " " " " " " LivejUnbrowsed Terminal Leaders Abundance/0.25 m- " Abundance/O.Ol " " " " " " " " " " " " ,., m- Survey Results Mean willow heights were similar among sites when means were calculated for all willows sampled i~ each plot. However, omitting willows that grew in association with conifers reduced willow height means by 30 - 50%. I suggest that willows are generally taller when growing in association with conifer because 1) willows may have to grow taller to compete with conifers for light resources, 2) willows may benefit from the increased moisture that collects in the form of snow around tall conifers, and 3) conifers protect willows from browsing ungulates. Basal stem frequencies are important indicators of browsing levels. Salix species reproduce largely through adventitious shoot production, which is stimulated when apical meristems are damaged or removed by herbivores (Bryant 1981). Any adventitious shoot, whose basal stem origin could not be seen or palpated below the leaf litter, was classified as a basal stem and was included with basal stem abundance data. Higher basal stem numbers at ReS were probably related to heavy browsing by large ungulates. TSR did not have high willow basal stem abundance, possibly because most willows were protected by conifers from browsing. Avian Census Results Overall, avian species richness was lowest at GTO and greatest at RCS. Total breeding bird densities were similar at all sites except MBC where density was low. It is likely that differences in site characteristics and locations �245 account for the observed differences. RCS and TSR sites have southeastern exposures while MBC and GTO sites are exposed to the north and northwest, respectively. RCS and TSR sites include wide topographic depressions (saddles) southeast of ridges. These topographic characteristics, combined with prevailing (NW) winds, cause snow to accumulate in these areas. Consequently, deep snow patches and wet areas (solifluction pools and associated drainages) persist well into the breeding/growing seasons at these sites. In contrast, MBC and GTO sites are slightly concave to convex slopes that are exposed to prevailing winds, which makes them drier and cooler than RCS and TSR sites. White-crowned sparrow densities were much lower at MBG than elsewhere. These sparrows have been shown to prefer nesting sites in open stunted woodland and scrub (Harrison 1984), and sites that are proximal to water (Morton et al. 1972); MBG was the driest site, which could explain the lower sparrow density at MBC. Sparrows used high perches in dwarf conifers, almost exclusively, for territorial and mate attraction vocalizations. Their preference for territories that included clumps of krummholz vegetation that were dominated by conifer species could also explain the low densities of sparrows at MBC. The ratio of dwarf conifer vegetation to willow vegetation is lower at MBC than at other sites (Braun 1969). It may be that grazing enhances white-crowned sparrow habitat. Sparrows were observed foraging in small open short-grass patches, which may be maintained or created by heavy grazing. Furthermore, browsing may discourage willows and reduce competition for conifers, cover which sparrows appear to prefer in RMNP krummholz areas. Sparrows consistently fled from forage patches into dense conifer krummholz when alarmed. Both Lincoln's sparrows and Wilson's warblers prefer dense shrub nest sites, especially in boggy areas or along water courses (Harrison 1984). Both species were found at or immediately adjacent to RGS and TSR sites where preferred nest sites were available. Neither species was recorded at GTO, but both were frequently heard just northwest of the site where krummholz was more prevalent and was proximal to water. Yellow-rumped warblers prefer to nest in open coniferous woodland, often at woodland edges (Harrison 1984). Typically, none of the study sites would be appropriate nesting habitat for this species, but MBC and TSR sites were close enough to treeline to explain the appearance of this species at these sites. It may be these birds used the sites for foraging only, although the record for TSR was based on repeated observations of a singing male whose territory partially overlapped the TSR study site. Single ye1low-rumped warbler males were observed on a number of occasions at MBG, but they were not heard singing. The TSR site included part of a rock wren territory. The apparently single male was observed singing from a number of rocky perches. Although rock wrens are known to nest in rocky alpine habitats (to 3350 m), alpine areas are not preferred (Braun 1980). Therefore, greater rock wren densities would not be expected at any study site. Horned lark and water pipit densities were similar among sites. Both species use open areas for nesting (Verbeek 1970, Harrison 1978), and are not as likely to be effected by browsing ungulates. �246 Counts of white-tailed ptarmigan were absolute. Most birds were responsive to playback tapes which revealed their presence. Low ptarmigan densities, sedentary behavior, and individual color-coded leg bands provided the conditions necessary for accurate counts. Furthermore, ptarmigan leave unique and obvious tracks in fresh snow. Since ptarmigan move primarily by walking, censuses conducted just after snow allowed detection of previously undetected non-territorial males and, in one case, a pair which was not responsive to playback tapes (GTO). All sites were censused at least once after fresh snow. SUMMARY AND CONCLUSIONS Ptarmigan densities at MBC and GTO were greater than at RCS and TSR. Historically, densities at RCS and TSR were similar to MBC and GTO (Braun 1969). The overall ptarmigan population decline (Fig. 1) has been a consistent trend for almost 10 years (Braun and Giesen 1988), and is largely accounted for by the depressed densities at RCS and TSR. Ptarmigan numbers began to decline 10 years after the 1968 decision by National Park Service (NPS) policy makers to discontinue elk management in RMNP. In an elk management statement (Natl. Park Servo 1988), the NPS described elk concentrations in RMNP as possibly being in excess of winter range capacities, largely due to elimination of useable habitats and dispersal areas outside the Park. If elk have exceeded traditional winter range capacities, then it is likely they are seeking non-traditional winter ranges and forage, such as alpine/krummholz areas and willows. The willow characteristics, which I labeled as indicators of heavy browsing (high basal stem abundance, extreme height variance, low bud abundance, low live/unbrowsed terminal leader abundance), tended to occur in those areas where ungulate pellet frequencies were highest. It is reasonable to conclude that elk are foraging on willows when they are using alpine/krummhclz habitats. Because ptarmigan densities are lower at RCS and TSR, it is also reasonable to conclude that willow habitat structure and willow food resource quality and/or availability have been altered by browsing elk, which has in turn caused a depression in ptarmigan densities. It is evident from ungulate pellet, willow, canopy cover, and ptarmigan census data that there is an inverse relationship between ptarmigan densities and browsed willows, minimal willow canopy cover, and ungulate pellet presence. Until willow data can be tested for statistical differences, however, the strength of this relationship cannot be ascertained. Therefore, I am unable to reject the null hypothesis that current patterns of habitat use by elk have no effect on ptarmigan densities. However, the decision by NPS staff to disallow the fencing experiment precludes further speculation regarding these relationships. As a result, I have submitted a proposal for another experiment which would allow investigation of responses of ptarmigan to different habitats, including habitats that seem to be unsuitable as a result of browsing by ungulates. �247 LITERATURE CITED Baker, D. L., and N. T. Hobbs. 1982. Composition and quality diets in Colorado. J. Wildl. Manage. 46:694-703. of elk summer Bear, G. D. 1989. Seasonal distribution and population characteristics of elk in Estes Valley, Colorado. Colorado Div. Wildl. Spec. Rep. 65. 14pp. Braun, C. E. 1969. Population dynamics, habitat, and movements of whitetailed ptarmigan in Colorado. Ph.D. Diss., Colorado State Univ., Fort Collins. l89pp. Braun, C. E. 1980. Alpine bird communities in western North America. Pages 280-291 in R.M. DeGraff and N.G. Tilghman, compilers. Workshop Proc. Manage. West. For. and Grasslands for Nongame Birds. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. INT-86. _____ , R. K. Schmidt, Jr. and G. E. Rogers. 1973. Census of Colorado whitetailed ptarmigan with tape-recorded calls. J. Wildl. Manage. 7:90-93. _____ , R. W. Hoffman, and G. E. Rogers. ecology of white-tailed ptarmigan Spec. Rep. 38. 38pp. 1976. Wintering areas and winter in Colorado. Colorado Div. Wildl. _____ , and K. M. Giesen. 1988. Population dynamics of white-tailed ptarmigan, Job Progress Rep., Colorado Federal Aid Project W-152-R. Apr. 1988. Bryant, J. P. 1981. Phytochemical deterrence of snowshoe hare browsing adventitious shoots of four Alaskan trees. Science 213:889-890. by Giesen, K. M., C. E. Braun, and T. A. May. 1980. Reproduction and nest-site selection by white-tailed ptarmigan in Colorado. Wilson Bull. 92:188-199. Green, R. A. 1982. Elk habitat selection and activity patterns in Rocky Mountain National Park, Colorado. M.S. Thesis, Colorado State Univ. , Fort Collins. 165pp. Harrison, C. 1978. A field guide to nests, eggs, and nestlings of North American birds. The Stephen Greene Press, Brattleboro, Vt. 4l6pp. Hobbs, N. T. 1979. Winter diet quality and nutritional status of elk in the upper montane zone, Colorado. Ph.D. Diss., Colorado State Univ., Fort Collins. 131pp. Hoffman, R. W., and C. E. Braun. 1975. Migration of a wintering population of white-tailed ptarmigan in Colorado. J. Wi1d1. Manage. 39:485-490. International Bird Census Committee. 1970. Recommendations for an international standard for a mapping method in bird census work. Audubon Field Notes 24:722-726. �248 Kufeld, R. C. 1973. 26:106-112. Foods eaten by the Rocky Mountain elk. J. Range Manage. May, T. A. 1975. Physiological ecology of white-tailed ptarmiga~ Colorado. Ph.D. Diss., Univ. Colorado, Boulder. 311pp. in , and C. E. Braun. 1972. Seasonal foods of adult white-tailed in Colorado. J. Wildl. Manage. 36:1180-1186. ptarmigan Morton, M. L., J. L. Horstmann, and J. M. Osborn. 1972. Reproductive cycle and nesting success of the mountain white-crowned sparrow (Zonotrichia leucophrys oriantha) in the central Sierra Nevada. Condor 74:152-163. National Park Service. 1975. Resource management plan: Rocky Mountain National Park and Shadow Mountain National Recreation Area. U.S. Dep. Inter., Natl. Park Serv., Estes Park, CO. 88pp. National Park Service. Natl. Park Servo 1988. Statement for management. U.S. Dep. Inter. NPS D-23d. Washington, D.C. 60pp. Olmsted, C. E. 1979. The ecology of aspen with reference to utilization by large herbivores in Rocky Mountain National Park. Pages 87-89 in M.S. Boyce and L.D. Hayden-Wing, eds. North American elk: ecology, behavior, and management. Univ. Wyoming, Laramie. Packard, F. M. 1947. A study of deer and elk herds of Rocky Mountain National Park. J. Mammal. 28:4-12. Ratcliff, H. M. 1941. Winter range conditions in Rocky Mountain Park. No. Am. Wildl. Conf. Trans. 6:132-139. National Schmidt, R. K., Jr. 1969. Behavior of white-tailed ptarmigan in Colorado. M.S. Th~sis, Colorado State Univ., Fort Collins. 174pp. Stevens, D. R. 1971. Plant succession as related to grazing on the upper montane region in Rocky Mountain National Park, Colorado. Proc. Northwest Sect., The Wildl. Soc., Abstract. 1980. The deer and elk of Rocky Mountain National Park: a ten-year study. U.S. Dep. Inter., Natl. Park Servo Rep. ROMO-N-13, Estes Park, CO. l63pp. Verbeek, N. A. M. 451. 1970. Breeding ecology of the water pipit. Auk 87:425- Willard, B. E., and J. W. Marr. 1970. Effects of human activities tundra ecosystems in Rocky Mountain National Park, Colorado. Conserv. 2:257-265. on alpine Biol. �249 APPENDIX A Definitions and Techniques Used for Willow (Salix) Shrub Measurements in Each m2 Sample Plot Canopy Cover - visual estimate of percent canopy cover for each plar.t species within m2, including willow shrubs and mat willow. Percent Dead - visual is dead. estimate Patch Diameter - approximate measured with meter stick. of percent diameter of Salix spp. shrub within of any Salix spp. clump within Patch Distance - distance from Salix spp. shrub within m2 and nearest spp. shrub not within m2, measured with meter stick. m2 that m2, Salix Height - average height of Salix spp. shrub within m2. Meter stick used to average arbitrarily selected heights (ground to tip at selected points); 2 measures taken for each 0.25 m2 containing Salix spp. shrub. No. Basal Stems - absolute count of basal stems within arbitrarily selected 0.25 section of m2. Determination of basal stem made on basis of whether basal stem could be palpated below leaf litter. No. Live Terminal Leaders with Terminal arbitrarily selected 0.01 m2. No. Dead or Browsed selected 0.01 m2. Terminal Leaders Buds - absolute - absolute count within No. Buds per Live Terminal Leader with Live Terminal arbitrarily selected 0.01 m2. No. Buds per Dead or Browsed Terminal arbitrarily selected 0.01 rnZ. Leader =Le~n~~~~~~~~~~~~~~~~w~i~t~h~T~e~rm~i~n~a~l~Bu~d cm ruler. B owsed Terminal Leaders ruler. count within arbitrarily Bud - average within - average within - average within - average within arbitrarily arbitrarily �250 APPENDIX B Definitions and Techniques Used to Measure Abundance of Herbivore Pellets in m2 Sample Plots Ungulate Pellets or Chips - record occurrence each sample plot. White-tailed Ptarmigan each sample plot. Lagomorph plot. Pellets Pellets Prepared by: Approved by: - record occurrence - record occurrence All pellets not collected ungulate pellets or chips in of ptarmigan or lagomorph pellets were removed from sample plots. \\~c_~ :' ,~~~v. Cjn ia P. Melcher Graduate Research Assistant 1/aJ'Z_~J Clait E. Braun Wildlife Research Leader pellets in in each sample �251 JOB PROGRESS REPORT Colorado State of: Project: W-152-R Upland Bird Research Work Plan: 22 Job Title: Avian Research Period Covered: Author: Job _1_ Publications 01 January through 31 December 1989 C1ait E. Braun Personnel: L. A. Benson, C. E. Braun, K. M. Giesen, R. W. Hoffman, J. W. Hupp, O. B. Myers, T. E. Remington, J. W. Schmutz, W. D. Snyder, M. A. Zablan, Colorado Division of Wildlife ABSTRACT Progress was made on preparing and submitting manuscripts to technical journals. The following technical papers and abstracts were published 1989. Benson, L. A. sagebrush Workshop. in 1989. Response of sage grouse to prescribed burning in the big type. Proc. 1989 Western Sage and Sharp-tailed Grouse Abstract. Braun, C. E. 1989. Impacts of reduced bag limits on sage grouse harvest and lek counts. Proc. 1989 Western Sage and Sharp-tailed Grouse Workshop. Abstract. Hoag, A. W. 1989. Plains sharp-tailed Colo.-Wyo. Acad. Sci. 21(1):11 .. Hupp, J. W.. and C. E. Braun. grouse during courtship. , and winter. grouse research in Colorado. J. 1989. Endogenous reserve s- of adult male sage ~ondor 91:266-271. 1989. Topographic distribution J. Wildl. Manage. 53:823-829. of sage grouse foraging Myers, O. B. 1989. Sage grouse use of fertilized rangeland. Western Sage and Sharp-tailed Grouse Workshop. Abstract. Proc. 1989 Remington, T. E. 1989. Why do grouse have ceca? A test of the fiber digestion theory. J. Exp. Zool. S~ppl. 3:87-94. Schmutz, J. A., and C. E. Braun. 1989. Reproductive Grande wild turkeys. Condor 91:675-680. performance of Rio in �252 turkeys. and W. F. Andelt. 1989. Nest habitat Wilson Bull. 191:591-598. use of Rio Grande wild Schroeder, M. A. 1989. Movement and lek visitation by female greater prairie-chickens: a test of the female preference hypothesis for lek evolution. J. Colo.-Wyo. Acad. Sci. 21(1):23. Zablan, M. A. 1989. Survival estimates of sage grouse under changing harvest regulations. Proc. 1989 Western Sage and Sharp-tailed Grouse workshop. Abstract. Prepared by _J.<::!%~U=-' ~Z=-';'---"~~==";:___ __ Clait E. Braun Wildlife Research Leader �253 JOB PROGRESS State of: Project: REPORT Colorado W-152-R Upland Bird Research Work Plan: 25 Job Title: Evaluation Farmin Period Covered: Author: Thomas Personnel: Job 1__ of Wildlife 01 January through Responses 31 December to Pesticides Used in Wheat 1989 E. Remington Todd Abell, Clait E. Braun, Richard W. Hoffman, Carol Mehaffy, Michael W. Miller, Thomas E. Remington, Joan Ritchie, Lyn Stevens, David A. Wilson, Colorado Division of Wildlife; Wendy Meyer, Frank Peairs, Stan Pilcher, Colorado State University; Claude Ross, Ted Warfield, FMC Corporation. ABSTRACT The impacts of two methods using pesticides to control pests in winter wheat on bird communities were investigated. These were aerial spraying of Lorsban (chlorpyrifos) or Di~Syston (disulfoton) to control Russian wheat aphids (Diuraphis noxia) in Spring and microtubule injection of Furadan (carbofuran) at planting to control grasshoppers. No dead or impaired birds were found during searches of 162 ha within 10 fields sprayed with either Lorsban (97 ha) or Di-Syston (65 ha). Fifteen active nests (or broods) of several bird species were ,found within sprayed fields and were not obviously affected. Searchers located 57% of carcasses placed in fields to evaluate search efficiency. Brain cholinesterase activity of horned larks (Eremophila alpestris) collected from a field 2 days after it was sprayed with Di-Syston appeared depressed relative to activity in birds collected from a field sprayed with Lorsban or unsprayed controls (avg. - 5.0, 8.2, and 6.7 ,umoles/min/g, of brain tissue, respectively). Spraying of Di-Syston, but not Lorsban, decreased (f < 0.0.5) survival of pheasant chicks slightly in a controlled experiment. Weight dynamics of chicks in pens within sprayed strips were similar to those in unsprayed strips. Spraying of Di-Syston or Lorsban to control Russian wheat aphids in Spring does not appear to impact birds significantly. Two horned larks and 1 meadowlark (Sturnella neglecta) were found dead during searches of 38 km around the perimeters of 13 fields 510 days after seed planting and microtube injection of Furadan. The meadowlark appeared to have been shot but no wounds or injuries were observed on the ,horned larks. Searcher efficiency averaged 69%. Furadan residues in grasshoppers averaged 0.22 mg/kg, a level unlikely to cause avian mortality. Residue analysis did not include toxic metabolites of Furadan, however. Brain cholinesterase activity of Canada geese (Branta canadensis) was unaffected by feeding (24 hours) within pens where 50 or 100% of wheat had been treated. ��255 EVALUATION OF WILDLIFE RESPONSES TO PESTICIDES USED IN WHEAT FARMING Thomas E. Remington P. N. OBJECTIVES 1. Determine acute mortality of wildlife 1-3 days post-spray prescribed levels of Di-Syston and chlorpyrifos. resulting 2. Recover carcasses of wildlife suspected of dying from pesticide poisoning for analysis of cause of death and pesticide residue levels. 3. Monitor impacts of spraying prescribed chlorpyrifos on avian nesting success. 4. Determirie level of brain cholinesterase depression in songbirds and pheasants 24-48 hours post-spray as an index to both pesticide exposure and potential effects. 5. Measure toxicity of prescribed 7-10 day-old pheasant chicks. levels of Di-Syston levels of Di-Syston from or and chlorpyrifos to SEGMENT OBJECTIVES 1. Measure acetylcholinesterase activity in brain tissue of carcasses dead in, or collected from, wheat fields during spring 1989. 2. Conduct pesticide residue analysis of tissues from birds found dead in wheat fields and exhibiting ~ 50% brain acetylcholinesterase inhibition. 3. Search wheat fields for dead or moribund of Di-Syston, chlorpyrifos, and possibly 4. Determine rates of carcass by search crews. 5. If warranted by results of 1989 spring field season, pesticide in wheat and/or insects in wheat fields will be measured. 6. Compile wildlife following carbofuran. removal by scavengers, and analyze data, and prepare progress found application and carcass detection residues reports. METHODS Wheat Aphid Study Three research approaches were used. Transects were conducted to search for dead or impaired wildlife in sprayed fields. Exposure of breeding birds to pesticides (potentially causing sublethal effects on behavior) was evaluated by collecting horned larks from sprayed and unsprayed fields. Acute toxicity and indirect effects of these pesticides on survival of pheasant chicks was evaluated by experiment. Specific methodology for each approach follows. �256 Transects were conducted by 4-5 people walking abreast, about 20 rows apart 13 days post-spray until 8.1 ha had been searched per field. Most searches were conducted with the rows, although it was found that as wheat grew taller visibility of carcasses was greatest walking against the rows. Search efficiency was measured as the percent recovery of house sparrows (Passer domesticus) placed in sprayed fields prior to the search. To confirm that carcasses would remain 1-3 days post-spray, the disappearance rate of house sparrow carcasses placed in sprayed fields was measured. Horned larks were collected from sprayed and unsprayed fields with a shotgun and immediately frozen. Brain cholinesterase activity was measured by the Ellman procedure as described by Hill and Fleming (1982). The design of the pheasant chick experiment is illustrated in Fig. 1. Nine strips, 121.9 m wide and 381 m long, were marked with flagging and randomly assigned to 1 of 3 treatments; Di-Syston, Lorsban, or unsprayed control. Within each strip, 3 of 36 possible 0.1 ha (1/4-ac) pen locations were randomly selected. Pens were constructed of 61 by 2.54 cm (24" by 1") mesh poultry netting supported by rebar and aluminum rods. Pens were offset 13 m from either edge of the strip to prevent or minimize drift of pesticide across treatments. Within the center of each pen a 9.75 m2 circular pen was constructed of 1.22 m (48") hardware cloth. Ten, 6-day old pheasant chicks were placed in each pen from 0830 to 0950. Di-Syston and Lorsban strips were sprayed with 1.12 kg active ingredient (a.i.) per ha or 0.84 kg a.i./ha, respectively. Spraying began at 1030 and was completed by 1200 hours. Conditions were ideal for spraying; sunny, warm and little or no breeze. To facilitate recovery and prevent escape, chicks were initially placed in the small pens. Chicks were removed at the end of each day and kept indoors at 32.1 C (90 F) and provided pelleted chick feed and water. Thirty (of the original 90) chicks from each treatment were individually marked by wrapping a numbered strip of scotch tape around 1 leg. These chicks were weighed each morning and returned to the larger pens for 7 days to evaluate the suitability of sprayed areas as brood habitat. Remaining chicks were labelled with nail polish which identified the treatment to which they were exposed and kept indoors to monitor subsequent mortality (2 legs painted - Lorsban; 1 leg painted - Di-Syston; neither painted - control). Carbofuran Study The purpose of this research was to gather preliminary information on mortality or morbidity of wildlife thought to be at risk from microtubule injection of Furadan as an at-planting treatment to control grasshoppers. Effects on passerine birds were evaluated by searching borders of treated fields (Furadan 4F at a rate of 0.5 fluid ounces per 305 linear meters) for dead or impaired birds at about 1 and 2 weeks after planting. Searcher efficiency was estimated as recovery of house sparrow carcasses placed within field margins prior to the search. The effect on Canada geese of exposure to furadan-treated wheat was evaluated by penning birds captured by cannon net into 1 of 3 enclosures consisting of 6 rows of treated wheat, 6 rows of treated and 6 rows untreated wheat, or 6 rows of untreated wheat (check). These enclosures were within 12, 305-m long strips of 6 rows of wheat each planted on 19-20 August in a field near �I I 122-m SPRAY STRIPS .- : .. . CIJ i~[:[:::[:: ...... ::::::: :::: E ex) ,.... C? . .......... .. . -- n LJ ·· .. · .... ..... . . - - . . . . n . - ::: : ••• _0 . ~ - - tc ~ - . :z - o o - - - 13-m BUFFER Fig. 1. Experimental design and layout of treatment strips and pens used to assess toxicity of Lorsban and Di-Syston to pheasant chicks. h) l_" -., �258 Briggsdale. Furadan 4F was applied to alternate strips by microtubule injection at a rate of 0.5 fluid ounces per 305 linear meters. The birds left within the pens for a day and a half to feed. They were then killed CO~ asphyxiation. Heads were removed, placed on dry ice, then tra~sported and stored within a freezer at -60 C. Brain acetylcholinesterase activity determined following Hill and Fleming (1982). RESULTS were by to was and DISCUSSION Russian Wheat Aphid Study Mortality Transects.--Ten fields, 162 ha total, (65 ha treated with Di-Syston, 97 ha treated with Lorsban) were searched and no dead or impaired wildlife were found. Fields were searched 3 hours (1), 1 day (6), 2 days (1), or 3 days post-spray (2). Horned larks, lark buntings, meadowlarks, and mourning doves were common in sprayed fields and appeared to act normally. Nests with eggs or chicks and/or fledged baby birds were found in some sprayed fields, usually when the attending parent(s) flushed. We located 7 horned lark nests (2 with eggs, 2 with chicks) or fledged broods (3 broods of 1-3 chicks), 5 lark bunting nests (5 with eggs), and 3 mourning dove nests (2 with eggs, 1 with young). At least in these instances, spraying did not impair normal reproductive behavior such as incubation and feeding young, nor did it kill dependant young in nests. This was confirmed by follow up visits to most nests located within a day of spraying. We recovered 57% (12 of 21) of carcasses placed in fields prior to searches. Carcasses were removed from wheat fields slowly by scavengers (Fig. 2); 75% were still present and visible 3 days after placement and 50% were present after 6 days. These data suggest that if significant mortality had occurred as a result of spraying we would have detected it. Exposure of Breeding Birds.--A pilot collection effort was made this spring, if results indicate significant exposure then more extensive collections are justified. Horned larks were collected from a field 2 days after Di-Syston spraying (5), from another field 1 day after Lorsban had been sprayed (5), and from a rangeland area about 20 km away (3 to serve as controls). Cholinesterase activity appeared depressed in horned larks collected from the field sprayed with Di-Syston relative to those collected from the field sprayed with Lorsban or the unsprayed controls (~± S.E. - 5.0 ± 0.5, 8.2 ± 0.8, and 6.7 ± 1.0 ~moles/min/g of brain tissue, respectively). Sample sizes are too small to make definitive conclusions. Results do suggest 20-30% depression in acetylcholinesterase activity, indicative of exposure to DiSyston. Further collections are warranted next spring. These enzyme rates are only about 50% of levels found in horned lark brain tissue by McEwen et al. (1986). This may be due to the prolonged (4-5 months) time carcasses were frozen. This will be investigated. McEwen et al. (1986) found that aerial spraying of Lorsban on winter wheat at 0.56 and 1.12 kg a.i./ha to control cutworms resulted in significant depression of horned lark cholinesterase activity at 3 and 9 days post-spray. There was no evidence of suppression 1 day after spraying with Lorsban. Pheasant Chick ToxicitY.--Di-Syston spraying lowered (f < 0.05) 48-hour, but not 24-hour survival of pheasant chicks (Fig. 3). An average of 7.3, 8.2, and �259 18 16 14 (/) W (/) (/) <t 0 12 a: <t 0 ZI 10 8 6 ~~--~--~--~--~--~--~~--~--~--~--~--~--o 1 2 3 4 5 6 7 DAYS Fig. 2. Removal rate of house sparrow carcasses from wheat fields in Spring. �IV Q\ 24-HOUR MORTALITY 30 10 SUBSEQUENT SURVIVAL 28 r:«. .. 8 Fig. 3. Survival of pheasant (1.12 kg a.i./ha). 26 chicks 1-5 days following spraying with Lorsban (0.84 kg a.i./ha) or Di-Syston o �261 8.2 (of 10) chicks survived 48 hours per pen sprayed with Di-Syston, Lorsban or unsprayed, respectively. Subsequent survival was similar among treatment groups. A storm cell passing to the south late the afternoon of the day of spraying lowered temperatures dramatically and may have exasperated toxicity of Di-Syston (Rattner et al. 1982). Given that Di-Syston and Lorsban have similar avian toxicities (Smith 1987), it is puzzling that chick mortality differed. This may be due to lower application rates of Lorsban (0.84 kg a.i./ha versus 1.12 kg a.i./ha) or to higher rates of Di-Syston reaching ground (chick) level (F. Peairs, pers. commun.). Chick weight dynamics were similar across all treatments (Fig. 4). Birds generally lost weight when kept outside. This suggests that wheat fields are poor brood habitat for chicks of this age, at least in the absence of a hen. Carbofuran Study Mortality Transects.--Thirty-eight km around the perimeters of 13 fields were searched for dead or moribund birds within 5-10 days of planting. Four of these fields (12 km) were searched again 2-3 weeks after planting. Two horned larks and 1 meadowlark were found dead. None of these carcasses was fresh enough for measurement of acetylcholinesterase activity. The meadowlark had injuries consistent with death resulting from shotgun pellets (radius and ulna of right wing broken, hole in right thigh and right side of pelvis broken). No wounds or injuries were detected in the horned larks. One carcass was little more than a feather pile when found and may have died as a result of predation or it may have been scavenged. The other horned lark had 3 wheat seeds within it's stomach. Consumption of treated seeds is a possible route of exposure. A horned lark was found dead within a treated strip at the Severance study site and also contained 7 wheat seeds in it's stomach. Acetylcholinesterase activity of this bird was 62% depressed relative to 2 control larks shot on the same day. There may have been additional mortality as well, since several feather piles were observed over the course of the pronghorn stl~dy. The experimental design used may have increased potential exposure of birds to treated seeds. The seed drill was in and out of the ground 6 times over 305 m to create 6 treated strips. If the microtubule injector and drill are left on while the drill is pulled out of the ground at the end of each strip, then treated wheat seeds will be exposed on the soil surface. Data should be obtained on furadan and total carbamate residues of treated wheat seeds so risks from this exposure can be evaluated. Searcher efficiency was evaluated in 5 fields and averaged 69% (25 of 36 carcasses recovered). Efficiency within each field was 67, 75, 63, 87, and 60%. These results indicate that had significant mortality occurred we would have detected it, assuming carcasses remained until our searches. This assumption was not tested directly during this study. It appears that mortality of passerines is limited under this application method of furadan to the borders of fields. These results should be interpreted cautiously, however. An inherent weakness in this approach is that birds could feed within treated field margins, flyaway to die elsewhere, and go undetected during our searches. This could be a problem with horned larks who have very large home ranges in fall and winter. Exposure of insectivorous birds to furadan-contaminated grasshoppers was presumably �N or", 40 ,..... -- CONTROL ------ DI-SYSTON 35 ::I: /:~j------I'" <, <, <, ..••. .// .-.._ .._ .._ .._ .._ .._ .._ .._ .._ .._ .._ .. w //------.'/ g 30 UJ -W // ::> - -- ~/ 0 /.7 . ...•......... _1 .. /·· -, -- / // ••••• •..., ..••. /f CJ ~ <, LORSBAN m ~ I- <, // / w g en w g en ••••• ••••• o 0 ::> 25 ::> 20 1 2 3 4 5 6 7 DAYS SINCE SPRAYING Fig. 4. Weight dynamics (1.12 kg a.i./ha). of pheasant chicks sprayed with Lorsban (0.84 kg a.i./ha) or Di-Syston 8 �263 minimal since few insectivorous birds were observed during our searches. Fall migrations may mitigate potential exposure of these birds to furadan, although the extent to which this occurs may vary annually. There may he potential for mortality from treated grasshoppers. A starling (Sturnus vulgaris) was found dead at the Severance study site with no apparent injuries and a partially digested grasshopper in it's stomach (along with several Russian olive [Eleagnus angustifolia] drupes. The premise of death from ingestion of a single grasshopper is not supported by toxicity assessments from furadan residues measured in grasshoppers collected from treated fields. Maximum furadan residue of composite grasshopper samples was 0.22 mg/kg. Ass~~ing a 50 g (0.05 kg) bird and a grasshopper weight ',f 0.89 g (0.00089 kg), ingestion of a single grasshopper represents about U L_ the LD50 for red-winged blackbirds and about 0.33% of the LD50 for house sparrows. Residue analysis did not include toxic carbamate metabolites of furadan. Risks to insectivorous birds are mitigated by timing of migrations and low furadan residues in grasshoppers, but additional experiments with caged birds may be useful. The primary risk appears to be to granivorous birds, principally horned larks and meadowlarks. Data on residue levels of wheat seeds sprayed with furadan and left on the soil surface should be obtained. Experiments with caged horned larks and meadowlarks would establish whether consumption of treated seeds is toxic. If treated seeds are toxic to these birds, a more difficult task would be to establish with what frequency mortality occurs under normal planting conditions. Repetitive transects appear to be the only means to determine this. Effects on Canada geese.--Thirteen geese were captured by cannon net on 7 December and transported to the Briggsdale study site. One goose died enroute. We finished marking, wing clipping, and handling birds about 1330 hours. After some initial pacing along the fence, birds began to feed. Feeding appeared heavy throughout the following day. Geese were removed and sacrificed just before dusk on 8 December. Brain acetylcholinesterase activity was unaffected by this exposure (Table 1). Two wheat samples collected at. the Briggsdale site prior to this study had furadan residues of 0.06 ppm. Residues at the Loveland site were 0.84 and 1.16 ppm while treated wheat at the Severance site had residues of 0.34 and < 0.05 ppm. Variation among sites seems large since all 3 were planted at the same time using the same equipment and applicator. It is not surprising that no effect was observed in geese at the Briggsdale site given these residues. In retrospect the Loveland site would have been a better test. It's possible that furadan at the Briggsdale site had been metabolized in the soil or wheat and was still present as a toxic metabolite. Apparently inconsequential fields with higher residue needed. impacts on Canada geese may not be typical of levels. Additional work on residue decay is �264 Table 1. Brain acetylcholinesterase activity of 12 Canada geese after feeding in pens containing untreated, 50% furadan treated or 100% furadan treated wheat. Treatment Mean ± S.D. Untreated 50% Treated 1007. Treated 1502 967 1007 959 867 751 1296 975 1072 1256 881 964 1108 ± 263 972 LITERATURE ± 234 1043 ± 162 CITED Anonymous. 1988. The Russian wheat aphid: a serious new pest of small grains in the Great Plains. Great Plains Agric. Counc. Pub1. 124. 6pp. Hill, E. F., and W. J. Fleming. 1982. Anticholinesterase field monitoring and diagnosis of acute poisoning. Chem. 1:27-38. poisoning of birds: Environ. Toxico1. McEwen, L. C., L. R. DeWeese, and P. Sch1adwei1er. 1986. Bird predation on cutworms (Lepidoptera: Noctvidae) in wheat fields and chlorpyrifos effects on brain cholinesterase activity. Environ. Entomo1. 15:147-151. Peairs, F. B., K. G. Beck, W. M. Brown, Jr., H. F. Schwartz, and P. Westra. 1988. 1988 Colorado pesticide guide - field crops. Colorado State Univ., Coop. Ext., Agric. Exp. Stn. XCM-45. Rattner, B. A., L. Sileo, and C. G. Scanes. 1982. Hormonal responses tolerance to cold of female quail following parathion ingestion. Biochem. Physiol. 18:132-138. and Pest. Smith, G. J. 1987. Pesticide use and toxicology in relation to wildlife: organophosporous and carbamate compounds. U.S. Dep. Inter., Fish and Wild1. Servo Resour. Publ. 170. 17lpp. Snyder, W. D. 1984. Ring-necked pheasant nesting ecology on the high plains. J. Wi1d1. Manage. 48:878-888. Prepared bY~ Thomas E. Remington Wildlife Researcher and wheat farming � https://cpw.cvlcollections.org/files/original/b4588c857ba1ad76abd3bef193ce974d.pdf b377ee66f3f44046e3220a0171ffc9a7 PDF Text Text 1 Colorado Division Wildlife Research July 1990 of Wildlife Report JOB PROGRESS REPORT State of Colorado Project No. W-lS3-R-3 Work Plan No. Job No. _ Multispecies 7 Period Covered: Author: ~l Mammals Research Research Terrestrial Research Publication, Editing and Library Service July 1, 1989 - June 30, 1990 J. A. Boss, L. H. Carpenter Personnel: R. B. Gill, N. McEwen, L. Lovett, K. Williams, all Mammals Researchers C. Hanna and Abstract During the 1989-1990 Segment, 4 books were purch~sed for permanent reference by DOW personnel. Twenty-six additional publications were located, ordered, and obtained free of charge for use. Six of these were purchased, obtained on Interlibrary Loan, or given to the library. An Additional 431 individual references requested by Mammals Researchers were located by library staff and made available for use. About 10 of these requests were not available locally and were obtained through interlibrary loans. Sixteen manuscripts were published in various journals. ��3 MAMMALS PUBLICATION, EDITING AND LIBRARY SERVICES Jacqueline A. Boss and Len H. Carpenter P. N. OBJECTIVES To provide a centralized support program for manuscript editing and library services to facilitate publishing results of research conducted in projects 01-03-047 - 11700 and 01-03-048 - 11700 and 16700. SEGMENT OBJECTIVES 1. To provide coordinated and efficient editing and library services and publish findings for all Colorado Mammals Research programs. 2. To provide for the centralized support program for Mammals Research editing, library, and publishing services so that Mammals Research scientists can be most efficient in publishing results of their research. SUMMARY OF SERVICES Publications purchased with Mammals Research funds and placed in the Research Center Library Callicott, J. B. and A. Leopold. 1989. In defense of the land ethic: essays in environmental philosophy. State Univ. of New York Press, Albany, NY. 325pp. King, C. 1989. Natural history of weasels and stoats. Assoc., Ithaca, NY. 253pp. Comstock Publishing Phillips, B. G. and A. M. Phillips III. 1987. Annotated checklist of vascular plants of Grand Canyon National Park. Museum of Northern Arizona, Flagstaff, AZ. 79pp. Yates, S. 1988. Adopting a stream: a Northwest handbook. Press, Seattle, WA. l34pp. Univ. of Washington Publications obtained free or at low cost In addition to books purchased with Federal Aid Funds, about 26 free reports and short publications from state or federal agencies or from private sources were located, ordered, and obtained for use by Mammals Research personnel. Theses purchased, obtained on Interlibrary Loan or as gifts for use by Researchers Ackerman, B. B. 1989. Visibility bias of mule deer aerial census procedure in Southeast Idaho. Ph. D. Diss., Univ. of Idaho, Moscow, ID. l16pp. �4 Banks, J. L. 1964. Fish species distribution in Dinosaur National Monument during 1961 and 1962. M. S. Thesis, Colorado State Univ., Fort Collins, CO. 96pp. Bertagnoli, G. G. 1986. Availability and use of foods by black bears in Wisconsin. M. S. Thesis, Univ. of Wisconsin-Stevens Point, Stevens Point, WI. 42pp. Brian, N. J. 1982. A preliminary study of the riparian coyote willow communities along the Colorado River in Grand Canyon National Park, AZ. M. S. Thesis, Northern Arizona Univ., Flagstaff, AZ. 84pp. Gerhardt, D. R. 1989. Population dynamics, movement and spawning habitat of channel catfish in the Powder River System, Wyoming-Montana. M. S. Thesis, Univ. of Wyoming, Laramie, WY. 94pp. Koehler, G. M. 1988. Demography of a low productivity Ph. D. Diss., Univ. of Idaho, Moscow, ID. 32pp. bobcat population. Neve, L. L. 1976. Live history of the roundtail chub, Gila robusta grahami, at Fossil Creek, Arizona. M. S. Thesis, Northern Arizona Univ., Flagstaff, AZ. 46pp. Schreckengast, G. E. 1988. River otter reintroductions M. S. Thesis, West Virginia Univ., Morgantown, WV. in West Virginia. l02pp. Staines, B. W. 1970. Management and dispersion of a red deer population in Glen Dye, Kincardineshire. Ph. D. Diss., Univ. of Aberdeen, Aberdeen, Scotland. pp. Stevens, L. E. 1984. Aspects of invertebrate herbivore community dynamics Tamarix chinensis and Salix exigua in the Grand Canyon. M. S. Thesis, Northern Arizona Univ., Flagstaff, AZ. l62pp. on 1989. Mechanisms of riparian plant community organization and succession in the Grand Canyon, Arizona. Ph. D. Diss., Northern Arizona Univ., Flagstaff, AZ. llSpp. Tango, P. J. 1988. Home range .. of reintroduced river otter in West Virginia. M. S. Thesis, West Virginia Univ., Morgantown, WV. l17pp. Whiting, W. R. 1988. Implementing prohibitive policy: the Endangered Species Act. M. S. Thesis, Univ. of Wisconsin-Green Bay, Green Bay, WI. 80pp. Zabel, C. J. 1986. Reproductive behavior of the red fox (Vulpes vulpes) : longitudinal study of an island population. Ph. D. Diss., Univ. California, Santa Cruz, CA. 98pp. Zeckmeister, M. 1985. Population characteristics of unexp10ited beaver muskrat populations. M. S. Thesis, Univ. Wisconsin-Stevens Point, Stevens Point, WI. 4Spp. Reference document location and and delivery The Research Center Library staff also located and delivered about 431 individual articles on request for Mammals Researchers during this segment; a �5 about 10 were not available locally and were obtained through interlibrary loan procedures. Manuscripts published Job Progress Reports; Federal Aid. All studies. Anderson, A. E., D. C. Bowden, and D. E. Medin. 1990. Indexing the animal fat cycle in a mule deer population. J. Wildl. Manage. 54: (In Press) Bear, G. D., G. C. White, L. H. Carpenter, R. B. Gill, and D. J. Essex. Evaluation of aerial mark-resighting estimates of elk populations. Wildl. Manage. 53:908-915. 1989. J. Carpenter, L. H. 1989. Colorado's liability for big game damage to livestock forage. Pages 96-100 in Ninth Great Plains wildlife damage control workshop proceedings, April 17-20, 1989, Fort Collins, Colorado. USDA Forest Service, Rocky Mtn. Forest and Range Exp. Stn., Fort Collins, CO. Freddy, D. J., E. R. Ryland, and R. M. Hopper. 1990. In L. A. Renecker (ed.) Proceedings of the Second International Wildlife Ranching Symposium, Edmonton, Alberta, June 1990. Colorado's wildlife ranching program: the Forbes Trinchera experience. (In Press) Gill, R; B., and T. D. I. Beck. 1990. Black bear management plan. Div. of Wildlife, Div. Rep. No. 15. 44pp. Colorado Green, R. A., and G. D. Bear. 1990. Seasonal cycles and daily activity patterns of Rocky Mountain elk. J. Wildl. Manage. 54:272-279. Harlow, H. J., T. D. I. Beck, L. M. Walters, and S. S. Greenhouse. 1990. Seasonal serum glucose, progesterone, and cortisol levels of black bears (Ursus americanus). Can. J. Zool. 68:183-187. Hobbs, N. T. 1990. Diet selection by generalist herbivores: a test of the linear programming model. Pages 395-414 in Hughes, R. N. (ed.), Behavioural mechanisms of food selection. NATO ASI Series. Vol. G 20: Ecological Sciences. Springer-Verlag, Heidelberg, NY . . 1990. Interactions of vertebrates with crown fire regimes: chemical, structural, and spatial dynamics. In R. D. Laven and P. N. Omi (eds.), Pattern and process in crown fire ecosystems. Princeton University Press, Princeton, NJ. (In Press) __ , M. W. Miller, J. A. Bailey, D. W. Reed, and R. B. Gill. 1990. Biological criteria for introducing large mammals: using simulation models to predict impacts of competition. Trans. N. Amer. Wildl. and Natur. Resour. Conf. 55: (In Press) _____ , and T. A. Hanley. 1990. Habitat evaluation: do use/availability data reflect carrying capacity? J. Wildl. Manage. 54: (In Press) Kufeld, R. C., D. C. Bowden, and D. L. Schrupp. 1989. Distribution and movements of female mule deer in the Rocky Mountain foothills. J. Wildl. Manage. 53:871-877. �6 _____ , D. C. Bowden, and D. L. Schrupp. 1989. and why. Colo. Outdoors 38(5):36-37. Where the deer are - Miller, M. ~., fi._T. Hobbs, and M. C. Sousa. 1990. Detecting stress responses in Rocky Mountain bighorn sheep (Ovis canadensis): reliability of cortisol concentrations in urine and feces. Can. J. Zool. 68: (In Press) Smith, M. H., K. T. Scribner, L. H. Carpenter, and R. A. Garrott. 1990. Genetic characteristics of Colorado mule deer (Odocoileus hemionus) and comparisons with other cervids. Southwest. Nat. 35:1-8. Trust, K. A., M. ~. Miller, J. K. Ringelman and I. M. Orme. 1990. Effects ingested lead on antibody production in mallards (Anas platyrhynchos). J. ~ildl. Dis. 26: (In Press) of ~alsh, N. E. 1990. Responses of bull elk to simulated elk vocalizations during rut. M. S. Thesis, Colorado State Univ., Fort Collins, CO. 97pp. Prepared by Len H. Carpenter wildlife Research Leader �Colorado Division Wildlife Research July 1990 of Wildlife Report JOB PROGRESS REPeRT State of Colorado Project No. ~W_-~1~5~3_-~R~-~3 _ Mammals Research Work Plan No. __~2 _ Deer Investigations Development of Census Methods for Deer in Plains Riverbottom Habitats Job No. 7 Period Covered: July 1, 1989 - June 30, 1990 Author: R. C. Kufeld Personnel: D. Bowden, D. Younkin ABSTRACT White-tailed and mule deer, radio-collared in the South Platte Riverbottom during January and February, 1987, 1988, and 1989, were located at approximately 2-week intervals throughout the segment. A computer system for analyzing data from tracking radio-collared deer during the course of the study was prepared. Movement data from 29 radio-collared deer which have died or whose transmitters have quit and movement patterns, to date, of 21 radiocollared deer that are still alive and currently being monitored, suggest that deer in the South Platte Riverbottom fall into 4 movement categories. These categories include resident deer which occupy the same general area yearlong, and migratory deer which occupy separate winter and summer areas. These patterns were observed for both mule deer and whitetails and are described in detail. ��9 DEVELOPMENT OF CENSUS METHODS FOR DEER IN PLAINS RIVERBOTTOM HABITATS Roland C. Kufeld P. N. OBJECTIVES 1. To determine seasonal movements and home range size of white-tailed and mule deer in plains riverbottom habitats. 2. To develop and test methods for estimating size of deer populations in plains riverbottom habitats. SEGMENT OBJECTIVE To determine seasonal movements and home range size of white-tailed and mule deer in plains riverbottom habitats. STUDY AREA The study area was described by Kufeld (1989). METHODS AND MATERIALS White-tailed and mule deer, radio-collared in the South Platte Riverbottom during January and February, 1987, 1988, and 1989, (Kufeld 1987, 1988, 1989) were located at approximately 2-week intervals throughout the fiscal year. Deer locations were recorded by UTM coordinates and plotted on USGS 1:50000 scale maps. Vegetation type for each deer location was also recorded. A computer system for analyzing data from tracking deer that were radiocollared during the course of this study was prepared. The system was used to analyze part of the data collected for radio-collared deer that have died or whose transmitters have quit prior to writing of this report for purposes of including that information in this report. Since many of the radio-collared deer are still alive and are still being located at 2-week intervals, a complete analysis of data must await termination of monitoring of those deer. The area which encompassed all observed locations for an individual deer during a specific time period was determined using the minimum convex polygon feature in version 1.2 of program McPaal developed at the Smithsonian Institution, Front Royal, VA 22630. Median activity centers for each such group of locations were computed according to Barry et al. (1984). Distances along the river channel between selected points, herein referred to as "river km", airline distances between selected deer locations or median activity centers and the closest point on the river channel, and airline distances between selected deer locations or median activity centers were computed using version 6.03 of program SAS, SAS Institute Inc., SAS Circle, Cary, NC 27512. During initial planning for this study, which included discussions with Colorado Division of Wildlife Northeast and Southeast Regional personnel, it was decided to concentrate first efforts on a single river system. The South Platte River from Platteville, Colorado to the Nebraska State Line was �10 selected as the initial study area, and is the area where the study has been conducted since 1987. This study area is in the Northeast Region. It was agreed that upon completion of work on the South Platte other river situations would be addressed. The South Platte phase is expected to terminate during the winter of 1990-91. During this project segment meetings were held with Southeast Regional personnel and plans were made to shift emphasis to selected rivers in southeastern Colorado. RESULTS AND DISCUSSION Movement data from 29 radio-collared deer which have died or whose transmitters have quit (Tables 1 through 4), and movement patterns, to date, of 21 radio-collared deer that are still alive and are currently being monitored, suggest that deer in the South Platte Riverbottom fall into 4 movement categories. Since data in Tables 1 through 4 represent only part of the sample of radio-collared deer in the study, because some study deer are still alive, mean areas which encompassed all deer locations by species and sex and comparisons of means between species, sexes, or movement categories are not presented for data in Tables 1 and 2. A much more in-depth analysis of these data will be presented in a subsequent report when monitoring of remaining radio-collared deer has been completed and all data derived from the study become available. This will include information on habitat selection, more on movements, and a discussion of how findings from this study apply to development of a census technique for plains riverbottom habitats. Movement categories are described as follows: Movement Category 1: Deer which remain in or near the South Platte Riverbottom throughout the year and occupy a segment of riverbottom to 20 km in length. from 2 Movement Category 2: Deer which remain in or near the riverbottom throughout the year, but travel relatively long distances (30 to 120 km) up and/or downstream. Movement Category 3: Deer that spend most of the year, including winter, in or near the riverbottom, but during late spring or summer they leave the riverbottom and spend at least several weeks out on the plains. Radiocollared deer that exhibited this behavior returned to the same section of riverbottom sometime before December. During the period they were in the riverbottom they occupied a riverbottom segment from 1 to 12 km in length. Those that survived more than 1 year occupied the same general area each summer (Tables 1 and 2). Departure and return dates, length of time these radio-collared deer spent away from the riverbottom, and distance they traveled from the river varied among individual deer within the 3rd category. Some individual deer were gone from the riverbottom for only a few weeks, while others were gone for months (Tables 3 and 4). Some individuals moved to plains habitats only 1 or 2 km from the riverbottom, while others traveled to plains habitats more than 35 km from the riverbottom (Tables 1 and 2). Movement .Category 4: Deer that live on the plains and rarely visit the riverbottom. Several radio-collared deer, including those which have since died and those still alive were trapped in the riverbottom, but shortly after being tagged they moved out onto the plains and were rarely �11 or never again located in the riverbottom during more than 2.5 years of monitoring. All 4 categories have radio-collared deer of both species (mule deer and whitetails) except that no radio-collared mule deer are in category 2. Most of the radio-collared deer are in category 1 with category 3 ranking second. Categories 2 and 4 contain relatively few animals (Tables 1 and 2). The white-tailed doe in movement category 2 (Tables 2 and 4) had a complex movement pattern which involved several centers of activity, all of which were located in the riverbottom but separated by relatively long distances. The deer was radio-collared 1-18-87, 1.9 river km downstream from Weldona, Colorado. Between 3-6-87 and 8-27-87, 14 locations were in an area of 0.3 km2 centered 22.7 river km upstream from its trapsite and 4.2 river km upstream from Orchard, Colorado. Between 9-12-87 and 10-13-87 it moved downstream 120.6 river km to a point near Iliff, Colorado. Between 10-27-87 and 5-28-89, 42 locations were in an area of 8.6 km2 centered 17.0 river km upstream from its easternmost location near Iliff. This area was in the vicinity of Dune Ridge State Wildlife Area, which is located about 8 km southwest of Sterling, Colorado. During the 10-27-87 to 5-28-89 period, however, it made 2 trips to a point centered 32.6 river km upstream near Messex State Wildlife Area. It was located there 3 times between 11-1 and 11-29-88, and 3 times between 3-28 and 4-24-89. Those 6 locations were in an area of 0.9 km2• After each visit to the Messex area it returned to the vicinity of Dune Ridge and it died there on 5-28-89. White-tailed doe 9791, in category 3 (Tables 2 and 4), spent the winter in the riverbottom in a relatively small area, but during summer it travelled such long distances that it could rarely be found. It was radio-collared 2-3-87 5.9 river km downstream from of Hardin, Colorado. It spent the winters of 1986-87 and 1987-88 in the riverbottom in the vicinity of its trapsite. Between 4-17 and 9-12-87 it could not be located despite an intensive search by aerial telemetry of the area encompassed by a perimeter extending along Interstate 25 from the Wyoming State Line south to the U.S. Air Force Academy, east to Limon, north to the Wyoming State Line, and west to Interstate 25. The South Platte River from Platteville to Julesburg, Colorado, was also searched. On 9-12-87 the deer was back in the vicinity of its trapsite where it spent the winter. It left its winter area the following April and on 4-2988 it was located near Roggen, Colorado, 17.5 km from its winter median activity center and 13.5 km from the nearest point on the South Platte River Channel. On 7-25-88 it was relocated 19.8 km south-southeast of Akron, Colorado, 105.9 km fro. its winter median activity center and 51.6 km from the nearest point on the South Platte River Channel. Two weeks later it could not be found within a 24-ka radius of that location, and it was never again relocated. Study area priorities that have been established by Colorado Division of Wildlife Southeast Region personnel for continuing the study in the Southeast Region are: (1) Arkansas River from John Martin Reservoir to the Kansas State Line, and the lower 16 km of Big Sandy Creek, (2) Arkansas River from Fowler to LaJunta, and Fountain Creek from Colorado Springs to Pueblo, (3) South Republican River from treeline to the Kansas State Line, and (4) Big Sandy Creek from Simla to Hugo. Objectives and procedures will be the same as those employed during the South Platte River phase of the study. Fieldwork for the southeastern Colorado phase will begin in December, 1990. �12 LITERATURE CITED Berry, K. J., P. W. Mielke, and K. L. Kvamme. 1984. Efficient permutation procedures for analysis of artifact distributions. Pages 54-74 in H.J. Hietala, ed. Intrasite spatial analysis in archaeology. Cambridge Univ. Press, Cambridge, U.K. Kufeld, R. C. 1987. Development of census methods for deer in pla~ns riverbottom habitats. Colo. Div. Wildl., Wildl. Res. Rep. July (1):13-19. 1988. habitats. Development of census methods for deer in plains Colo. Div. Wildl. Res. Rep. July (1):11-21. riverbottom 1989. Development of census methods for deer in plains habitats. Colo. Div. Wildl. Res. Rep. July (1):11-17. riverbottom Prepared by --,-~__:._ __ ~_·_C..:::..._..;_%dc--l· Roland C. Kufeld Wildlife Researcher r-W_' _.~ __ �13 Table 1. Movement patterns of radio-collared mule deer tagged in the South Platte Riverbottom that have died or whose transmitters have ~it. Deer location Distance from MAC Distance between winter and area ~Km2l' to river ~knQ2 Movement 10 No_ Sl.JIIlIer Annual Annual Winter Winter Sl.JIIlIer sl.Jllller MACS ~I(ml Sex categorJ! 0.2 9521 4.8 F 9522 2.7 0.2 9551 5.3 0.2 9652 3.1 0.1 9671 5.7 0.2 9732 6.6 0.2 M 3 F 9382 9291 9539 9631 9970 9452 9651 9701 4 F 9859 Area which enc~ased 0.2 3.1 0.5 0.6 11.1 1.6 1.9 3.6 6.43 0.9 0.4 0.2 0.3 0.2 5.6 16.7 26.0 1.7 6.8 17.8 29.1 1.9 3.1 4.8 5.2 11.43 31.4 3.5 0.7 0.3 0.0 1.6 14.7 0.9 1.5 14.8 1.6 28.2 2.3 all deer locations. ~istanc:e frOllMedian Activity Center (MAC) to the nearest point on the river channel (KIll).Median Activity Centers were computed as described by Berry et al. (1984). 3This deer spent 2 s~rs in this area. Table 2. MOVeMent patterns of radio-collared white-tailed deer tagged in the South Platte Riverbottom that have died or whose transmitters have ~it. Deer location Distance from MAC Distance between area (Km2l' to river 0("Q2 winter and Movement SI.Jlllle!" MACS (Km) Sex 10 No. Annual Winter Summer Annual Winter Summer categorJ! F 0.3 15.9 9252 6.1 9262 0.3 9731 0.3 4.2 8_3 9921 0.1 0_3 9971 6.8 M 2 F 3 F M 9351 9361 9391 9770 6.2 7.7 18.5 10.8 0.3 0.3 0.2 0.1 95113 9370 9780 'Area which enc~ssed 13.4 10.4 3.1 0.1 0.2 36.0 34.3 13.7 7.8 0.3 2.1 0.5 0.1 19.2 17.3 23.8 28.6 all deer locations ("",2). ~istance frOllMedian Activity Center (MAC) to the nearest point on the river chamel Activity Centers were ca.puted a. described by Berry et al. (1984). ~ovements of this deer are described in the text. (KIll). Median ""ean distance frOll3 Median Activity Centers (Orchard, Messex, DI.I"eRidge) to the nearest point on the river channel (KIll). �14 Table 3. N~r of locations and dates when radio-collared IIIJledeer in movement category 3 were away from the riverbottom during late spring and/or summer. Movement No. of locations Dates of summer plains ~riod Annual category Sex lJinter Summer 1st year 2nd year 10 No. 49 1 F None 9521 29 None 9522 None 9551 32 None 32 9652 64 None 9671 None 9732 16 9382 3 4 F F None 35 9291 9539 9631 9970 18 8 23 11 10 13 21 4 6-29 5-25 5-30 7-17 9452 9651 9701 32 10 8 20 14 12 5-25 to 8-17 6-30 to 10-28' 5-30 to 10-13 9859 8 12 5-30 to 10-13 to to to to 11-1 10-22' 10-13 6-8 8- 18' to 10-28 6-19 to 11-28 'Deer found dead or was killed on plains as of last date. Table 4. N~r of locations and dates when radio-collared wnite-tai led deer in movement category 3 were away from the riverbottom during late spring and/or summer. Movement Dates of summer plains ~riod No. of locations 1st year 2nd year category Sex 10 No. Annual lJinter Summer 15 None F 9252 24 None 9262 None 9731 15 None 9921 48 None 9971 17 None None None None M 9351 9361 9391 9nO 25 56 22 22 2 F 9511 66' 3 F 9809 9791 27 21 6 M 9370 9780 10 18 5 7 'Movements of this deer are described in the text. 1>eer found dead or was ki lled on plains as of last date. 6-1 1 to, 7-29 7-15 to 9-7 2 6-30 to 9-12 " �15 Colorado Division Wildlife Research July 1990 of Wildlife Report JOB PROGRESS REPORT State of Colorado Project No. W-153-R-3 Work Plan No. ~3 Job No. 2 Period Covered: Author: Mammals _ Research Elk Investigations Trapping, Transporting, of Elk at Livestock-Elk and Maintenance Grazing Study July 1, 1988 - June 30, 1990 G. D. Bear Personnel: B. Rakestraw, C. Woodward, C. Reichert, M. Bauman, B. Dupire, R. Harthan J. Madison, J. Haskins, ABSTRACT A total of 212 elk were trapped near Meeker, Craig, and Hayden, Colorado, to provide cows for stocking the experimental pastures on the Little Snake River Wildlife Area north of Maybell, Colorado. The pastures were stocked with 54 adult cows in late December, which were removed in early April. heavy snow accumulations, cold temperatures, and depleted range conditions contributed to heavy elk losses in the heavy and medium density pastures during the last 6 weeks of the grazing period. Telemetry-collared elk and visual observations indicated elk occupied the Little Snake River winter range from December through April. The collared elk then migrated to the traditional summer ranges north and south of the CraigHayden area. ��17 TRAPPING, TRANSPORTING, AND MAINTENANCE OF ELK AT LIVESTOCK-ELK GRAZING STUDY George D. Bear P. N. OBJECTIVE To provide assistance to the Livestock-Elk Grazing Study near Maybell, Colorado, by capturing and maintaining an experimental elk herd. SEGMENT OBJECTIVES 1. To trap, mark, stock, and maintain 54 adult female elk in the livestockelk grazing pasture complex during the period December 15 to April 20. 2. To determine seasonal movements released from the pastures. of radio-collared elk after they are METHODS AND RESULTS Capturing and Handling of Elk The usual amount of effort was put into repa~r~ng the fences and corrals the elk pens, repairing the elk traps, securing hay and other trapping supplies during the late summer and fall. at In late November and December trapsites were established at the following locations: (1) 5 mi southeast of Meeker near the Environmental Plant Center, (2) 28 mi east of Meeker on the Marvine Ranch, (3) Trapper Mine - 5 mi south of Craig, and (4) Senica Mine - 10 mi southeast of Hayden. These sites were selected because they were not open to hunting during the late elk hunting seasons (December-January). Details for handling elk at the trap sites and in the corral at the livestock-elk grazing pasture complex are presented in previous Federal Aid Reports. A total of 212 elk (101 cows, 84 calves, 12 yearling cows, 11 spikes, and 4 adult bulls) were captured from December 1 to February 14. Fifty-four cows were initially used to stock the experimental pastures (December 18 to December 16). Additional cows were kept in the pole-corral and hub to be used as replacements when needed. Weather conditions were very mild throughout January and the first half of February. There was less than 4 in of snow on the ground at anyone time. In late January the lack of snowcover made it necessary to provide water for the elk in the pastures. Daytime temperatures ranged from the mid-30s to low 50s; nighttime temperatures ranged from 0 to -lO°F. The elk in the experimental pastures did very well with these conditions. Elk in the high density pastures were replaced with new animals in February, as scheduled. A severe winter storm (38 in of as well as, cold stormy weather stressed the elk so weight loss and medium density pastures. A snow and temperatures -29°F) in late February, during the first week of March, severely was very noticeable for the elk in the high total of 27 elk died of malnutrition during �18 the following 6 weeks and left many others very weak and in poor condition. Sixteen of these 27 elk died in the high density pastures, in spite of the February rotation. The remaining 11 deaths occurred in the medium density pastures; none in tte low density pastures. Because of the poor range conditions and high elk mortality, elk were removed from the pastures a week early (April 7-12). Shrubs grew very well (10-12 in) last summer, in spite of the dry conditions; but forbs and grasses did not put on any new growth. Many of these shrubs (Artemisia ~, Chrysothamnus sp., Purshia tridentata, Eurotia sp.) maintained the elk in early winter; however, they were severely overgrazed. With the food supply reduced, elk in the high and medium density pastures were forced to subsist primarily on Artemisia tridentata in late winter. Elk in the low density pastures fared better; here the shrubs were not overgrazed, and some residue grasses remained. Elk Movements Migration patterns this year were similar to those reported in previous years. Although the December hunting season kept the elk moving around in smaller groups, they were commonly observed in the vicinity of the study area after December 1, then throughout the winter. As the snow melted and green grass became apparent in April, the elk started moving eastward toward higher elevations. An aerial survey on April 9 revealed a large concentration of elk north of Craig and only a few scattered groups in the vicinity of the study area. By early May, only an occasional elk was seen on the low winter range. Radio-collared elk migrated to the traditional high summer ranges north of Craig and Hayden and summer ranges at the head of Williams Fork and Maraposa Creek south of Craig and Hayden. Prepared by ~'6'.~~ ceorgeaear Wildlife Researcher �19 Colorado Division of Wildlife Wildlife Research Report July 1990 JOB PROGRESS REPORT State of C~o~l~o~r~a~d~o~ _ Project No. W-lS3-R-3 Work Plan No r ---::.3 _ 6 Job No. Period Covered: Author: Mammals Research Elk Investigations Effect of Elk Harvest Breeding Biology Systems on Elk July 1, 1989 - June 30, 1990 D. J. Freddy Personnel: M. Miller, T. Hobbs, C. Wetherill, M. Cousins, J. Olterman, Colorado Division of Wildlife, G. White and N. Walsh, Colorado State University, and E. Ryland, Forbes Trinchera Ranch. ABSTRACT We evaluated effects of time and ambient temperature on progesterone concentrations in plasma and serum collected from elk. Progesterone concentrations differed by blood type (~= 0.01), elk (~- 0.002), and time since collection (l~ 0.024). Concentrations were greater in serum than in plasma and increased in both serum and plasma with time since collection. These results were surprising, and we plan to repeat the experiment in 1991. Reproductive tracts were collected from female elk in December by hunters on the Forbes Trinchera Ranch. Fetal sex ratios for 1989 were 12 M:24 F and were 49 M:Sl F for years 1986-89, pooled. In 1989, male fetuses were smaller than females in body size and weight. Size of male fetuses has declined since 1987 to a greater extent than size of female fetuses. Abstracts are included from the following publications: elk using p:r~gesterone assays and real-time ultrasound" elk to simulated elk voca.l.fz a t i.ons during rut". . "Pregnancy testing and "Responses of bull ��21 JOB PROGRESS REPORT EFFECT OF ELK HARVEST SYSTEMS ON ELK BREEDING BIOLOGY David J. Freddy P. N. OBJECTIVE To evaluate effects of harvest systems on breeding biology of elk. SEGMENT OBJECTIVES 1. Continue to determine reproductive status of elk and deer on the Forbes Trinchera Ranch using fetal collections and blood assays. 2. Provide administrative and technical assistance to the graduate student project investigating rutting-bugling behavior of bull elk on the Forbes Trinchera Ranch. 3. Prepare manuscript for publication summarizing reproductive measurements. ACKNOWLEDGMENTS We thank T. Thorne and H. Long of the Wyoming Game and Fish Department, Sybille Research Station, for providing blood from adult female elk for progesterone assays. METHODS AND MATERIALS Pregnancy Testing-Blood Assays We evaluated effects of time and ambient temperature on progesterone concentrations in plasma and serum collected from elk. Using a syringe, we collected 30 cc of blood via the jugular vein from each of 2 pregnant and 1 nonpregnant adult female elk on 2 May 1989. Blood from each elk was immediately divided into 20, 1.5 cc subsamples and maintained at ambient temperature during the 1 hr when blood was collected from all 3 elk. These 20 subsamples were allocated as follows: (1) 10 were placed into heparinized glass tubes (plasma) with 5 each to be stored at 24 C and 4 C for up to 24 hrs, and (2) 10 were placed into non-heparinized glass tubes (serum) with 5 each also stored at 24 C and 4 C for up to 24 hrs. At 1 hr post-collection (Time 0), 1 sample from each blood and temperature treatment for each elk (4 samples/elk) was centrifuged and plasma and serum were harvested and frozen at -18 C and all remaining samples were placed in either a refrigerator or container maintained at ambient temperature. At 3, 6, 12, and 24 hrs thereafter, samples were removed from their respective thermal environments, centrifuged, and plasma and serum were harvested and frozen at -18 C. Progesterone concentrations in each sample were determined by radioimmunoassay on 8 May by the Physiology Laboratory, Colorado State University, Ft. Collins, CO. Progesterone concentrations were analyzed using a randomized complete block (elk) for 2 way factorial with repeated measures (serial blood samples for time intervals) (Proc GLM, SAS 1988). �22 Fetal Collections Reproductive tracts of female elk were collected by hunters on the Forbes Trinchera Ranch on 9-11 and 16-18 December 1989. Tracts were deposited at check stations and kept cool until processing. Pregnancy status was determined from the presence of fetuses, embryos, and developed uterine tissue. Questionable uteri were preserved for later examination. Fetal measurements were made on fresh specimens (subsequently preserved) and followed definitions of Armstrong (1950). Fetal age was determined from growth curves of Morrison et al. (1959). Compliance with the request to collect reproductive organs was poorer than during the previous 3 years. RESULTS AND DISCUSSION Blood Assays Progesterone concentrations were most affected by blood type, individual elk, and time and less so by temperature. Overall, progesterone differed among elk (~= 0.002) and between plasma and serum ( ~ = 0.011) (Fig. 1). Progesterone concentrations were not different between ambient and refrigerated samples (~= 0.783), although there was some tendency for higher concentrations of progesterone in refrigerated samples of both plasma and serum (Fig. 1). There were no interactions between temperature and blood type (~~ 0.65). This pattern of results also generally held true within each time period. Progesterone concentrations were affected by time since collection (~ = 0.024), most noticeably by an increase in plasma samples at 24 hrs postcollection (Fig. 1). There were no interactions between time and elk, temperature, or blood type (~> 0.40). we were surprised by the differences in progesterone values between plasma and serum, by the lack of differences between refrigerated and ambient samples, and by the lack of a steady decline in progesterone over time. These results contrast with observations in muskoxen (Rowell and Flood 1987). ~e are cautious about these results and plan to repeat the experiment with captive elk in January and May 1991. ~e also have delayed submitting a completed an internally reviewed manuscript to The Journal of ~ildlife Management (Appendix A) pending the outcome of experiments in 1991. Fetal Pregnancy Collections-Forbes Elk Rates Pregnancy rates for adult cows (~ 1 yr old) averaged 78% with a range of 7782% from 1986-89 (Table 1). Pregnancy rates were 90% for prime-age adults but were 20% for yearlings and 60% for cows aged 11+ years. Pregnancy was not observed in calves. Litter size was 1 in all but 3 (2%) of 151 litters. The 3 sets of twins were: 2 females and 1 male and 1 female in cows 9 and 12 years old, respectively in 1986, and 2 females in a 6 year old cow in 1989. Infected uteri not capable of supporting pregnancy occurred in 5 (3%) of 193 adults examined. Infections were in 1 yearling and 4 cows ~ 13 years old with 3 found in 1986, 1 in 1988, and 1 in 1989. �23 Fetal Sex Ratios In 1989, the fetal sex ratio was 12 M:24 F and the ratio pooled among years was 49 M:5l F (Table 2). Fetal sex ratios continued to alternately favor males and females between years (Table 2, Freddy 1989). Fetal Size Male fetuses length, and been larger declined in Conception were hind than size slightly smaller than females in body weight, crown-rump foot length in 1989 (Table 3). In previous years, males have females (Freddy 1989). Since 1987, male fetuses have to a greater extent than females (Table 3). Dates Conceptions occurred from 18 September to 26 October, a 39 day interval. Median conception date was 2 October which was the latest date observed since 1986 and about 4 days later than the average median date from 1986-88 (Freddy 1989, Fig. 2). Fetal Collections-Forbes Deer Collections of female mule deer for reproductive and physiological measurements did not occur as planned in March, 1989. Scientific collection of deer was not considered prudent at this time. Bugling Behavior of Bull Elk The study "Responses of bull elk to simulated elk vocalizations" was completed in June, 1990, by master of science degree candidate Noreen Walsh, Department of Fishery and Wildlife Biology, Colorado State University. The abstract of this thesis is presented in Appendix B. LITERATURE Armstrong, R. A. 1950. Fetal development Amer. Mid. Nat. 43:650-666. CITED of northern white-tailed deer. Freddy, D. J. 1989. Effect of elk harvest systems on elk breeding Colo. Div. of Wildl. Game Res. Rep. July: 35-60. biology. 1959. Breeding seasons Morrison, J. A., C. E. Trainer, and P. L. Wright. in elk as determined from known-age embryos. J. Wildl. Manage. 23:27-34. Rowell, J., and P. F. Flood. 1987. concentration between collection 51:901-903. Changes in muskox blood progesterone and centrifugation. J. Wildl. Manage. SAS Institute, Inc. 1988. SASjuser's Inc., Cary, N. C. 1028pp. Prepared by guide, version 6.03. SAS Inst. �24 Table 1. Pregnancy rates for age classes of female elk collected on the Forbes Trinchera Ranch in December 1986-89. 1986 n Preg Age" (yrs) 1987 n Preg Year 1988 n Preg 1989 n Preg 1986-88 Preg %Preg n 1 2 3-4 5-6 7-8 9-10 11-12 13-19 6 7 6 3 4 1 2 5 2 7 6 3 4 1 2 3 7 5 15 10 5 3 1 3 0 5 15 9 4 3 0 2 7 6 19 12 8 2 0 7 2 4 17 11 7 2 0 4 5 3 12 12 5 5 3 4 1 2 10 11 5 5 2 2 25 21 52 37 22 11 6 19 5 18 48 34 20 11 4 11 20 86 92 92 91 100 67 58 Totals 34 28 49 38 61 47 49 38 193 151 78 aAge for ~2 from replacement and wear, for 3+ from dental cementum. Table 2. Fetal sex ratios for age classes of female elk collected on the Forbes Trinchera Ranch in Decembe 1986-89. Age" (yrs) M 1 2 3-4 5-6 7-8 9-10 11-12 13-19 1 1 4 3 3 0 2 3 Totals 17 Total Fetuses 1986b F U M 1987 F U M 1988 F U M 1989 F U % 1986-89 F M U Male 0 2 1 0 0 2 1 0 1 4 1 0 1 0 0 0 0 3 3 2 2 1 0 1 0 2 11 7 2 1 0 1 0 0 1 0 0 1 0 0 1 2 8 8 5 1 0 1 0 2 5 3 2 1 0 2 1 0 2 0 0 0 0 0 1 0 4 4 0 0 1 2 0 2 6 7 4 4 1 0 0 0 0 1 1 1 0 0 3 0 6 8 19 23 17 17 10 8 2 8 3 2 7 3 2 4 4 1 2 2 0 0 100 43 45 50 56 20 60 70 6 7 12 24 2 26 15 3 12 24 3 67 69 15 49 30 38 44 39 151 aAge for ~2 from replacement and wear, for 3+ from dental cementum. bFetal sex M=ma1e F=fema1e U=unknoWll. �25 Table 3. 1989. Year/ Statistic Measurements of elk fetuses from Forbes Trinchera Body Weight {g} Female Male Crown-Rump Length {rrun} Male Female Ranch, Hind Foot Length {rrun} Male Female 29 Nov-5 Dec 1986 Mean SD min max n 27.6 13.8 12.2 58.5 17.0 20.9 7.0 11.9 29.0 6.0 90.2 16.7 63.5 115.5 17.0 86.0 9.5 72.0 94.0 5.0 20.5 4.8 13.5 28.5 17.0 19.8 2.7 l6.5 23.0 5.0 60.4 33.2 12.0 135.0 24.0 141.4 21.1 113.0 180.0 12.0 115.4 23.3 66.0 151.0 24.0 42.3 10.9 31.0 68.0 12.0 30.3 8.8 14.0 46.0 24.0 66.7 29.7 23.0 120.0 15.0 120.0 19.9 77 .0 163.0 26.0 121. 7 17.9 87.0 150.0 15.0 32.6 7.7 17.0 47.0 26.0 33.1 7.0 20.0 45.0 15.0 60.0 45.4 4.9 149.0 24.0 102.4 37.5 35.0 169.0 12.0 111. 5 33.4 38.0 163.0 24.0 27.9 12.3 13.0 53.0 11.0 29.9 10.8 10.0 48.0 23.0 12-14 & 19-21 Dec 1987 Mean SD min max n 118.7 54.7 66.0 242.0 12.0 10-12 & 17-19 Dec 1988 Mean SD min max n 74.5 35.2 22.0 162.0 26.0 9-11 & 16-18 Dec 1989 Mean SD min max n 57.8 59.9 3.5 188.0 12.0 1986- �26 5 .•..... PLASMA24C SERUM 24C PLASMA4C -----6---. SERUM 4C • - 4.5 ....................................... ---8-· . __ E ....._ C) c: w 4 Z o a: w Q .... ..•.........• ...............• . •...........:::.. "'"'.:.~.~.. ...••., 3.5 l- ...... ~...... '."<: ............ & ::;''_ :-- - - -£3" ••• t/) W .... ~ o a: ...•...........................................•. ........... _.:0-. 3 e, ......... _ _ _ _:_ •._--~ __.,_---_ ~_-------- ----8- - 2.5 _ -2 1.5 o 3 6 12 24 HOURS POST-COLLECTION Fig. 1. Progesterone concentrations from 0 to 24 hours post-collection. of values from 3 captive elk. in plasma and serum at 24 C and 4 C Each data point represents the average �27 50 I en Z 40 YEARLY MEDIAN DATES ~ I- [I -e. 0 1986 - n = 26 l- w (.) 30 - ~ 1987 ---_ ..__ .' n = 37 Z 0 (.) I- 20 EJ - 1988 --_ ... _------- n = 44 Z W (.) a: w e. I 1989 10 ----- n = 35 f-- r j]i 0 I I 9/8 t I> I> 9/18 9/28 I 10/8 ~ ro v "'l )<1 I 10/18 10/28 I I 11/7 Xi 11/17 MONTH AND DAY (Begin S-day intervals) Fig. 2. Conception dates for elk on the Forbes Trinchera Ranch, 1986-89. �28 APPENDIX PREGNANCY TESTING David J. Freddy, 80459 ELK USING PROGESTERONE Colorado Division A ASSAYS AND REAL-TIME of Wildlife, ULTRASOUND P.O. Box 252, Kremmling, CO Michael W. Miller, Colorado Division of Wildlife, Prospect Street, Fort Collins, CO 80526 Research Center, 317 W. Gary C. White, Department of Fishery and Wildlife University, Fort Collins, CO 80523 Biology, Colorado LaRue Johnson, College Veterinary Collins, CO 80526 Medicine, Colorado State State University, Fort Abstract: We evaluated blood progesterone radioimmunoassays (RIA), a blood progesterone ELISA kit, and real-time rectal ultrasound for assessing pregnancy status of adult (~l yr old) elk (Cervus elaphus nelsoni). Progesterone was a significant (f < 0.001) predictor of pregnancy status and concentrations in December and January >1.8 ng/ml indicated elk were pregnant with 95% probability. Accuracy of the ELISA kit varied with progesterone levels but was 88% accurate when progesterone was >2.0 ng/ml. Real-time rectal ultrasound was accurate in assessing pregnancy status and should also prove beneficial in assessing fetal growth of elk. Pregnancy status of elk can be reliably determined using progesterone assays or real-time rectal ultrasound. ~ WILDL. MANAGE. 00(0):000-000 Key words: Cervus elaphus nelsoni, progesterone, ultrasound Colorado, elk, pregnancy testing, �29 ABSTRACT OF THESIS RESPONSES OF BULL ELK TO SIMULATED ELK VOCALIZATIONS DURING RUT Responses of mature bull elk (Cervus elaphus nelsoni) to repeated hunter bugling were studied on the Forbes-Trinchera Ranch in south-central Colorado during September and October of 1988 and 1989. Individual bulls, identified by radio collars, were repeatedly approached and bugled. Treatment bulls were harassed with the sound of a shot after bugling sessions; control bulls were not harassed. Ability of bulls to learn to avoid hunter vocalizations after repeated harassment was tested using a logistic regression model. Inclusion of previous harassment (f = 0.003, 1988; f - 0.0001, 1989) in a model that fit the observed data suggests that previous harassment had a significant effect on bull movement toward observer in subsequent sampling sessions. A period of peak response to bugling was isolated based on bull movement toward observer and presence of bulging responses during sampling sessions. This period of peak vulnerability fell between 17 September and 2 October both years. In 1988, mean distance moved by harassed bulls within 24 hrs of harassment was found to be no different (f - 0.481) than distances moved by control bulls. Setting hunting seasons before and after a pre-determined window of peak response to bugling may be advisable in areas where younger bulls, who may not have learned to avoid a bugling hunter, are the primary breeders. Noreen E. Walsh Fishery and Wildlife Biology Colorado State University Ft. Collins, CO 80523 ��Colorado Division Wildlife Research July 1990 of Wildlife Report JOB PROGRESS REPORT State of Colorado Project No. W-1S3-R-3 Mammals Research Work Plan No. 3 Elk Investigations Job No. 7 Elk Census Methodology Period Covered: Author: July 1, 1988 - June 30, 1990 D. J. Freddy Personnel: G. White, G. Byrne, and D. Masden, Colorado and E. Ryland, Forbes Trinchera Ranch. Division of Wildlife, ABSTRACT Estimates of population sizes for elk and deer in the Troublesome sub-unit of Middle Park were obtained using systematically spaced aerial line transects. Additionally, an estimate of population size for' deer was obtained using a random quadrat (2.59 km2) sampling system. All flights were conducted using a Bell-Salay helicopter. The exponential polynomial (EXPL) , negative exponential (NEXP) , and the exponential power series (EXPS) sighting models fit the observed data for elk with about equal quality (f ~ 0.7310). Estimates of popUlation size for elk ranged from 3,659-4,263 with the EXPL model providing the best precision of ±43% (95% CI) of the mean. Estimates of popUlation size for deer ranged from 5,021-9,541 with an EXPL sighting model providing the best precision of ±13% of the mean. Estimated popUlation size for deer based upon quadrats was 1,848 and precision was ±32% (95% CI) of the mean. Line transects and quadrats provided ditferent estimates of population size for deer (f < 0.001)., Sighting distributions for elk and deer were spiked at the transect' line which suggested fundamental problems in either detecting'groups of animals or in assigning groups to distance Lntervals. Further evaluation of line transects and quadrats is warranted if large numbers of radio-collared elk and/or deer are used as a "known marked" popu lat.Lon to validate es t Lmace s provided by different techniques. ��33 ELK CENSUS METHODOLOGY David J. Freddy P. N. OBJECTIVE Evaluate methods to estimate numbers of elk during winter. SEGMENT OBJECTIVES 1. Determine efficacy of line transect methodology to estimate and mule deer on winter ranges shared by both species. numbers 2. Compare estimates of mule dEer density based on line transects quadrats in an area where both methods can be employed. of elk and ACKNOWLEDGMENTS Partial funding Foundation. for helicopter services provided by the Rocky Mountain Elk STUDY AREA The area selected for evaluating aerial line transects (Burnham et al. 1980, White et al. 1989) was the Troublesome portion of Game Management Unit (GMU) 18 within Middle Park, northcentral Colorado, between Highway 125 and Troublesome Creek and north of the Colorado River. Significant numbers of elk and mule deer reside in this relatively small area which can be efficiently sampled with aerial surveys. Primary vegetation types include sagebrush (Artemisia tridentata), aspen (Populus tremuloides), conifer forests (Pinus contorta, Pseudotsuga menziesii, Picea engelmanni), and mixed stands of aspenconifer. Terrain varies from rolling hills to steep canyons. METHODS AND MATERIALS Two sets of parallel transects, each having 26 transects systematically spaced at 1,000 m intervals, were flown to estimate numbers of elk and deer. These 2 sets resulted in transects occurring every 500 m across the sampled area. Transects were oriented on true north-south bearings perpendicular to changes in elevation, were delineated on 1:24,000 scale topographic maps, and were not marked with flight markers on the ground. Placement of transects allowed for counting elk and deer simultaneously. Line transects flown to estimate densities of elk totaled 948 km (588 mi) in length, were 1-15 km long, and were distributed within an area of 246 km2 (95 mi2) between elevations of 2,257-2,990 m (7,400-9,800 ft). Transects were limited to those areas where elk generally reside during January and February (pers. comm. R. Thompson, R. Firth, CDOW). The same line transects were flown to estimate densities of deer but only deer found at elevations S 2,590 m (8,500 ft, primarily sagebrush habitat) were �34 counted. With this restriction, line transects for deer totaled 602 km (374 mi) in length, were 1-14 km long, and were distributed within an area of 166 km2 (64 mi2) which was also the area delineated for a quadrat (1 mi2) sampling system used to estimate numbers of deer in the Troublesome area during the last 22 yrs (Gill 1969). One set of transects was flown each morning and afternoon on 9 and 11 January (4 replicate flights) using a Bell-Soloy helicopter flown at 65-80 kmph (40-50 mph) and 35-50 m above the ground or tree canopy. A navigator and observer were responsible for observing elk or deer. The observer, seated on the right, estimated perpendicular distances to and counted those groups of elk or deer located from the transect center line to the right. The navigator, seated in the middle, maintained course bearing, and located groups on or near the transect line. Observers were well experienced in aerial counts of elk and deer and practiced estimating distance intervals from the helicopter using markers placed at 10 m intervals from a practice transect line. We considered sets of transects to be independent and thus pooled results from all flights to derive estimates of elk and deer populations. We had no indication that counting elk or deer disturbed either sufficiently to cause them to move from 1 transect to another while flying one set of transects and thus, we feel duplicated counts within a set of transects did not occur. Estimates of population size derived from line transects followed methods outlined by White et al. (1989) and estimates derived from quadrats followed methods of Gill (1969) and Mendenhall et al. (1971). We wanted to compare estimates of population size for deer derived from line transects and quadrats. We, therefore, expanded an existing quadrat system from 10 to 30 quadrats by drawing at random an additional 20 quadrats to improve precision of the estimate (Freddy 1989). Quadrats were flown on 10 January using the same Bell-Soloy helicopter and pilot and flown at similar speeds and elevations above the ground as during line transects. At least 1 corner of each quadrat was marked on the ground to aid in locating quadrats from the helicopter. The navigator and observer both searched for and counted deer. RESULTS AND DISCUSSION Although we searched for deer and elk simultaneously on line transects, the 2 species were seldom seen in close proximity. We, therefore, believe that searching for both species had little effect on detecting either species. We found little evidence to suggest elk were moving prior to detection and moved little after detection. Elk were often bedded in aspen or conifer habitats. However, deer moved in response to the helicopter more than did elk. Although snow cover was nearly 100%, snow depth was only 4 cm at lower elevations and this did not deter deer from moving. Elk were often found in snow depths of 30-60 cm. Only 2 groups of deer were seen along line transects outside the sample area demarcated for quadrats. Line Transects-Elk Estimated population size for elk was 3,659-4,263 depending upon which sighting probability model was used (Table 1). The EXPL models provided the best precision which was ±43% of the mean (95% CI, Table 1). A minimum number of elk within the sampled area was 419 based upon elk classified to sex and �35 age during flights on 15 January 1990. A previous estimate for the same area based on one set of line transects flown in January, 1988, (Freddy 1988) was 1,276 with a known minimum of 744. The EXPL, NEXP, and EXPS probability models having center intervals of 0-15 m and strip widths of 95 or 155 m fit the observed data with about equal quality (f ~ 0.7310, Table 1). Enlarging or reducing the width of the center interval or the cut point for strip width generally resulted in models that were poorer in fitting the data (f < 0.100, see White et al. 1989). The unexpectedly high estimates of total elk resulted from high numbers of groups observed within the center line interval compared to numbers of groups seen within intervals away from the center line (Fig. 1). Probability of sighting groups decayed rapidly away from the center line which is cause for concern and suggests fundamental problems in detecting groups or assigning groups to proper distance intervals. Average group size was 11.59 ± 3.5 (95% CI) elk. Line Transects-Deer Estimated population size for deer was 5,021-9,541 (Table 2). The EXPL, NEXP, and EXPS sighting models with a cut-point of 95 m fit the data best (0.0908 ~ f ~ 0.2024, Table 2). Enlarging or reducing the width of the center interval or strip width produced poorer fitting models (f < 0.001). As with elk, high numbers of groups were observed within the center line interval compared to intervals away from the center line and probability of sighting groups of deer decayed rapidly away from the center line (Fig. 2). Rapid decline in groups of deer detected away from the center line was also found on line transects flown within the Piceance Basin of Colorado (White et al. 1989), on Forbes Trinchera Ranch in southcentral Colorado (January, 1990), and on Cedar Ridge (February, 1989), also in Middle Park (Fig. 2). Habitats were primarily juniper-pinyon woodland (Juniperus osteosperma-Pinus edulis) in the Piceance Basin, juniper-pinyon woodland and sagebrush parks on Forbes Trinchera Ranch, and predominately sagebrush with scattered clumps of juniper on Cedar Ridge. The EXPL sighting model generally fit these sets of data the best (see White et a1. 1989, for Forbes Trinchera f ~ 0.2579, for Cedar Ridge f ~ 0.7639). The data from Piceance Basin and Forbes were obtained by 2 different sets of observers and a third set of observers obtained the Troublesome and Cedar Ridge data but all data were collected using a Be11Soloy helicopter. The rapid decline in detecting groups away from the center line in all of these efforts suggests that this problem is not necessarily dependent upon observers or habitat but could be related to the type of helicopter used. Size of groups detected on line transects appears to increase in more open habitats. In the Troublesome, where deer were primarily in sagebrush, group size was 6.1 ± 0.64 (95% CI) deer. At Forbes Trinchera in juniper-pinyon and sagebrush habitats, group size was 4.2 ± 0.55 (95% CI); while on Cedar Ridge in sagebrush-juniper habitats, group size was 3.2 ± 0.81 (95% CI) deer. In the continuous juniper-pinyon habitat of the Piceance Basin, average group size ranged from 1.45-2.54 deer (White et a1. 1989). Quadrats-Deer Estimated population size for deer was 1,848 (n - 30 quadrats, Table 3). This estimate represented only 25% of the deer estimated by the best fitting EXPL model for line transects (Table 2). We expected quadrats to underestimate true population size because area-based sampling strategies assume 100% of the �36 animals present are counted and this seldom occurs. In juniper-pinyon, observers detected only 65% of the known deer on quadrats (Bartmann et al. 1986). In the open sagebrush vegetation, we might detect 80% of the deer under optimal conditions (LeResche and Rausch 1974); and if true, the true population of deer based on quadrat data would approach 2,310 deer. Given a worst case scenario of detecting only 65% of the deer on quadrats, we would expect a true population of 2,843 deer. Line transects estimated nearly 2.5x this number of deer and have been found to estimate 90% of the true population (White et al. 1989). I cannot explain the large discrepancy in estimates of population size between quadrats and line transects. Estimated population sizes based upon the original 10 or the additional 20 quadrats were not different (f < 0.01, t-test, Table 3). Frequencies of deer/quadrat were also not different between 10 and 20 quadrats (Chi-Square contingency - 0.34, P > 0.50, Table 4). Precision improved with increasing sample size in part because a finite population correction factor could be used, unlike line transects (pers., comm. G. White, Table 3). Quadrats, therefore, provided a consistent estimate of mean density (consistent bias) across different levels of sampling. Line Transects vs Quadrats-Deer Line transects provided a higher estimate of total deer than did quadrats (f < 0.001, t-test, Tables 2, 3) and provided better precision (± 13% vs ± 32%, 95% CI, Tables 2, 3). However, changing numbers of quadrats (sample units) had virtually no effect on estimates of population size, but changing strip width, and, therefore, the numbers of groups (sampled distances) used in calculations, or sighting models altered population estimates ~1.5x (Tables 2, 3). Massaging line transect data by altering cut points, center interval distances, or sighting models can produce different estimates of population size and is a hazard of the technique (White et al. 1989). Calculating population estimates based on quadrats appears more straight forward and less subject to alteration. Flying Effort Actual flying time used to count elk and deer along line transects was consistent among replicated flights (Table 5). However, flights conducted during morning hours always detected more groups of both elk and deer. Although replicated flights of transect sets 1 and 2 were to be alternately flown during am and pm periods, this did not occur. Set 1 was always flown during am, and set 2 during pm hours. Differences in numbers of groups detected could, therefore, be due to differences in sets of transects and not time of day. We feel time of day was a factor in detecting fewer groups during the pm flights, probably due to a decrease in animal activity or observer fatigue. We replicated flights of line transects to obtain anticipated minimums of 130 groups of elk (Freddy 1988) and 200 groups of deer (White et al. 1989) to achieve precision approaching ± 15%. We did not obtain the expected groups of elk but did achieve our expected precision for deer. Assuming line transects for deer accounted for 64% of the total time spent on transects, line transects for deer took 579 mins to complete compared to 445 mins to complete 30 quadrats (Table 5). �37 CONCLUSIONS Sighting distributions for elk and deer were spiked at the transect line as observed by White et al. (1989). This characteristic of line trans~ct data collected from a helicopter appears to be independent of observer or habitat type, at least for deer. For Middle Park, line transects produced surprisingly high estimates of population sizes for elk and deer. A fundamental question is why sighting distributions are so spiked at the transect line. Trying to answer this question will be difficult. Mounting a video camera inside of the helicopter (if possible) to record groups relatively close to the transect line may provide insight into whether the "heaping" of groups at the center line is due to incorrectly assigning groups to this interval or whether groups to the right of the center interval are not detected. A second question involves the accuracy of population estimates for both elk and deer. In free-ranging populations, the only possible means to estimate true density is to radio-collar up to 100 animals of each species and use these radio-collared animals as a "known marked" population to create a detection function when flying transects or quadrats. To evaluate the accuracy of either transects or quadrats for estimating populations of either elk or deer, this expensive radio-collaring alternative should be strongly considered. LITERATURE CITED Bartmann, R. M., L. H. Carpenter, R. A. Garrott, and D. C. Bowden. 1986. Accuracy of helicopter counts of mule deer in pinyon-juniper woodland. Wildl. Soc. Bull. 14:356-363. Burnham, K. P., D. R. Anderson, from line transect sampling 202pp. Freddy, D. J. 1988. July (1):78-82. and J. L. Laake. 1980. Estimation of density of biological populations. Wildl. Mono. 72. Elk census methodology. 1989. Elk census methodology. Rep. July (1):61-65. Colo. Div. Wildl. Game Res. Rep. Colo. Div. Wild1. Game Res. Gill, R. B. 1969. A quadrat count system for estimating game population. Colo. Game, Fish, & Parks Game Info. Leaflet 76. 2pp. LeResche, R. E., and R. A. Rausch. 1974. Accuracy moose censusing. J. Wildl. Manage. 38:175-182. and precision Mendenhall, W., L. Ott, and R. L. Scheaffer. 1971. Elementary sampling. Duxbury Press, Belmont, Calif. 247pp. of aerial survey White, G. C., R. M. Bartmann, L. H. Carpenter, and R. A. Garrott. 1989. Evaluation of aerial line transects for estimating mule deer densities. J. Wild1. Manage. 53:625-635. Prepared by ~ 0;;. Wildlife •FrdY Researcher �38 Table 1. Population estimates for elk based upon different sighting probability models for line transects, Troublesome sub-unit, Middle Park, January 1990. Modela Center Interval/ Cut Point (m) Groups n Chi-square Prob. (f) POIl· Size & 95% CI N Upper Lower Density Elk/mil EXPLb 0-15 / 155 66 0.8252 3659 5232 2086 38.5 EXPLb 0-15 / 95 57 0.7310 3664 5224 2104 38.6 NEXP 0-15 / 95 57 0.8248 3662 5380 1943 38.6 EXPS 0-15 / 95 57 0.7514 4263 9813 0 44.9 aModels are: EXPL=exponential polynomial, NEXP-negative exponential, EXPS-exponential power series. bThese models provided the best precision: ±43% of the population mean. Table 2. Population estimates for deer based upon different probability models for line transects, Troublesome sub-unit, January 1990. Modela Center Interval/ Cut Point (m) Groups n Chi-square Prob. (f) sighting Middle Park, PO!;!.Size ~ 95% CI Lower N Upper Density Deer/mil EXPL 0-15 / 155 185 0.0001 5021 7144 2898 78.4 EXPLb 0-15 / 95 139 0.0908 7496 8466 6526 116.9 NEXP 0-15 / 95 139 0.1420 7494 10,538 4451 117.0 EXPS 0-15 / 95 139 0.2024 9541 17,327 1746 149.0 aModels are: EXPL - exponential polynomial, NEXP - negative exponential, EXPS - exponential power series. bThis model provided the best precision: ± 13% of population mean. Table 3. Estimated size of the mule deer population in the Troublesome subunit of Middle Park, January, 1990 based upon deer counted on square-mile quadrats. Variances calculated using finite population correction factor. Quadrat System Original Additional All (N - 64) Quadrats n Mean 95% Lower 10 20 30 1891 1827 1848 506 1028 1264 C.1. Upper 3276 2625 2431 Precision % of Mean Density Deer/mil ± 73% ± 44% ± 32% 29.5 28.5 28.8 �39 Table 4. Frequencies of numbers of deer counted per quadrat for varying numbers of quadrats flown, Troublesome sub-unit, Middle Park, January, 1990. . Deer per Ouadrat Quadrats Flown Original 10 Additional 20 All 30 0-9 10-29 ~30 4 7 2 6 4 7 11 8 11 Table 5. Numbers of groups of elk and deer detected on transects and estimates of counting times for transects and quadrats flown in the Troublesome sub-unit, Middle Park, January, 1990. Flight Method Trans. Trans. Trans. Trans. Set Set Set Set 1 2 1 2 Right Rep Rep Rep Rep 1 AM 1 PM 2 AM 2 PM Trans. Totals Quadrats (30) for Deer Only Groups De t ec t.ed" Elk Deer Left Tot. Right 24 17 22 16 4 2 1 4 79 11 28 Courrt Lng'' Time (mins) 23 20 60 44 60 44 229 227 229 220 90 208 905 17 445 8Groups of elk were assigned as to either the left or right of center line. Groups to the left were generally close to the center line. Our searching intensity to the left was limited. Only groups to the right were used in calculations. We searched only to the right for deer. bTime shown is the best estimate of flying time used to count animals. Flying time to/from for refueling not included. �40 20 ~----------------------------------~ ELK TROUBLESOME en Q. ~ 15 o a: JAN 1990 o LL o n = 66 GROUPS 10 a: w r:a :E 5 ~ Z o ~~~~~~~,~~~~~~~~~~~~ LON o t.n t.n t.n M t.n t.n ,.... N lI::t LOCD r--CO t.n t.n t.n LO LO t.n t.n t.n CD r-- CO t.n LO M t.n t.n lI::t LO t.n C)~ en DISTANCE FROM CENTER LINE (m) Fig. 1. Numbers of groups of elk observed at different distance intervals ,from the center line of line transects, Troublesome sub-unit, Middle Park, January 1990. �41 70 60 50 40 30 20 10 t/) a. MULE DEER JAN 1990 . n= 185 groups .. 0 40 MULE DEER ~ 0 30 C!J u, 0 20 w m 10 ~ 0 a: TROUBLESOME 1 .....• -.- -- .. --- - __ n J.::::.. FORBES TRINCHERA cA ..N 1~~.Q _ _._._ = 106 GROUPS a: :i Z 14 MULE DEER 12 1·_··_·_-_··············· 10 __ ····_···················_··... . n 8 CEDAR RIDGE FEB 1989 - - ..- .. - - -.- ..-............. . -. _ . = 56 GROUPS 8 4 2 0 ,... It) o ,... It) It) It) N M It) It) It) It) CD ••••• It) en ,... It) It) co en DISTANCE FROM CENTER LINE (m) Fig. 2. Numbers of groups of mule deer observed at different distance intervals from the center line of line transects: TOP, Troublesome sub-unit, Middle Park, January 1990; MIDDLE, Forbes Trinchera Ranch, southcentral Colorado, January 1990; BOTTOM, Cedar Ridge, Middle Park, February 1989. �0-15 15 - 25 en ~ 3 95 -15 m 85 - 95 -- z en "lJ o c 0 co ::0 co ~ G') 55 - 65 II ::J ...•. (II » C 75 - 85 ::0 ...•. 0 en c.. en (II 45 - 55 35 -45 m 65 -75 z -i m 0 s:: 0 ,..::0 m 0 25 - 35 z C 0 NUMBER OF GROUPS m s:: 0 en m c m r 0 -i "::0 r m 0 N -1-' tv �43 70 60 50 40 30 20 10 0 en MULE DEER TROUBLESOME JAN 1990 .. n - 185 groups 40 MULE DEER FORBES TRINCHERA JAN 1990 D. ~ 0 a: 30 LL 20 a: w 10 e 0 m n = 106 GROUPS :E ~ Z 0 14 MULE DEER CEDAR RIDGE 12 ._._._ 10 _._ _ _ _ _ __ .--- n 8 FEB 1989 _.__ _-_ _ = 56 GROUPS _.__ .•._._ .._ _--_ .._._ .....• _ ----_ _ .._._ 6 - .. _ .._ .. _ __ . _ . . 4 2 0 It) ,.... It) 0') I o It) ,.... It) N It) M It) -.::t It) It) It) CD It) •••••• DISTANCE FROM CENTER LINE (m) ,.... ��Colorado Division Wildlife Research July 1990 of Wildlife Report JOB PROGRESS REPORT State of Colorado Project No. ~W_-~1~5~3_-~R~-~3~ Work Plan Mammals Research lA Multispecies Job No. 1 Animal and Pen Support Facilities for Mammals Research Period Covered: July 1, 1989 - June 30, 1990 Author: No. _ Investigations M. W. Miller Personnel: D. J. T. M. L. Baker, M. A. Wild, P. H. Neil, M. J. McArtor, R. B. Gill, M. R. Szymczak, D. A. Magnuson, R. Ritchie, C. Y. Irvin, S. M. Willis, B. J. Maynard, L. Stevens, N. T. Hobbs, and H. J. Lucking K. Ringelman, ABSTRACT The Colorado Division of Wildlife's Foothills Wildlife Research Facility (FWRF) maintained captive animals (up to 73 wild'and domestic ungulates of 6 species and 95 migratory and upland game birds of 7 species) and facilities supporting 9 different mammalian and avian research projects. Current facility management practices were assessed, and a plan was developed to outline needs and strategies for improving FWRF management. Over the next 5 years, objectives of FWRF operations are twofold: (1) to provide a~d maintain captive wildlifp. populations and facilities supporting CDOW's Terrestrial Wildlife Research Program, as well as programs of CDOW cooperators, and (2) to develop improved animal and facility management practices that will provide maximum research opportunities at minimum cost. Management strategies for meeting these objectives through three broad operational activities (animal maintenance, facility maintenance, and facility improvement/expansion) were detailed in the FWRF Operations Plan. ��I -s 4/ ANIMAL AND SUPPORT FACILITIES FOR MAMMALS RESEARCH Michael W. Miller P. N. OBJECTIVE To provide and maintain populations of captive animals and pen facilities support Mammals and Avian Research Programs. to SEGMENT OBJECTIVES 1. Maintain and improve animal research and holding 2. Coordinate 3. Maintain up to 15 elk, 30 mountain sheep, 30 pronghorn antelope, deer, and 6 domestic cows in suitable health to perform required experiments. 4. Conduct management experiments efficiency and efficacy. all rearing, training, maintenance, facilities. and research activities. 15 mule research to increase feeding and maintenance METHODS AND MATERIALS Routine animal care and facility maintenance activities supporting new and ongoing Terrestrial Wildlife Research Program projects were accomplished as previously described. In addition to these activities, current facility management practices were assessed and a plan was developed to outline needs and strategies for improving FWRF management. RESULTS AND DISCUSSION Based on assessment of current management practices and anticipated needs of the Terrestrial Wildlife Research Program over the next 5 years, the following Operations Plan for CDOW's Foothills Wildlife Research Facility was developed: Prepared hi bYLt~ Michael W. Miller Wildlife Researcher ��DRAFT PROGRAM NARRATIVE State of Colorado Project No. W-153-R-3 Work Plan No. __~l~A Job No. A. I Mammals Research _ Multispecies Investigations Animal and Pen Support Facilities for Terrestrial Wildlife Research NEED Reliable knowledge offers an essential foundation for policy decisions. Faced with needs for more sophisticated management techniques and growing public scrutiny of management practices, wildlife professionals have recognized the value of reliable data to their management decisions. Experimental studies of captive wild animals are an important source of scientific information used by wildlife biologists in developing resource management strategies. Because wildlife management issues are becoming increasingly complex, more, not less, science will be required to resolve those issues in the future. Wild animals tamed for research purposes afford wildlife scientists unique opportunities for studying processes that affect free-ranging individuals and populations. Many experiments conducted using captive wildlife couJ.d not be performed in the field. Moreover, the ability to control experimental conditions for captive wild animals vastly improves the reliability of data gathered from such studies. Over the past 15 years, the Colorado Division of Wildlife's Foothills Wildlife Research Facility (FWRF) has been central to captive wildlife research efforts in Colorado. Results of "laboratory" experiments conducted at FWRF have enhanced knowledge of ecology, physiology, and management of native wild ungulates and, more recently, migratory and resident game birds. There is little doubt that FWRF has contributed substantially to the overall productivity and success of CDOW's Terrestrial Wildlife Research Program. Developing and improving husbandry practices for captive wildlife and facilities for captive wildlife research, as well as ongoing needs for centralizing and coordinating research activities, have guided operation of FWRF over the last decade. In the next 5 years, emphasis needs to be shifted toward improving economy and utility of FWRF operations to fully exploit opportunities for gaining knowledge about wildlife. Maximizing efficacy and efficiency of established husbandry practices and enhancing facilities to reflect a growing diversity of wildlife research pursuits will be necessary for FWRF to serve the anticipated needs of CDOW's Terrestrial Wildlife Research Program. Here, planned strategies for improving economy and utility of FWRF operations during FY90-9l to FY94-95 are outlined. B. OBJECTIVES �50 DRAFT - To provide and maintain captive wildlife populations and facilities supporting CDOW's Terrestrial Wildlife Research Program, as well as programs of CDOW cooperators. - To develop improved animal and facility management practices that will provide maximum research opportunities at minimum cost. Specific objectives include the following: To reduce overall feeding costs by 10% for FY90-91 (based on FY89-90 costs); to establish a refined standard feeding program by FY92-93. To establish a conservation-oriented approach for providing utilities/services to FWRF; to lower utilities/services costs by 10% in FY91-92. To establish a standard program for evaluating health wildlife; to reduce overall animal health maintenance 10% in FY92-93. of captive costs for FWRF by To establish standard procedures for preventive maintenance and repairs at FWRF; to reduce overall facility repair costs by 10% in FY93-94; to reduce overall costs of routine/ preventive maintenance by 10% in FY94- 95. To enhance facilities research needs. C. EXPECTED RESULTS to serve a growing diversity of anticipated AND BENEFITS Availability of captive wildlife and support facilities enhances the productivity of CDOW's Terrestrial Wildlife Research Program by providing opportunities for scientific study of wild animals under controlled conditions. More efficacious and efficient husbandry practices will improve overall health of research subjects and add to existing knowledge about biology and ecology of those species. Enhanced facilities will broaden the diversity of wildlife research problems that can be addressed at FWRF. More economical and utilitarian operation of FWRF will free fiscal resources for use in additional research experiments, and will lower costjbenefit ratios for captive wildlife research. Success in bighorn sheep management is limited by effects of disease on longterm population performance; experiments at FWRF will be directed toward developing management options for bighorn disease problems. Efficacy and effect of various harvest strategies on elk population management is a pivotal issue; experiments at FWRF will focus on developing field techniques to evaluate nutrition, reproduction, and survival in elk populations subjected to alternative harvest regimes. Livestock and agricultural conflicts influence pronghorn management decisions; FWRF will provide pronghorn for pasture experiments examining livestock competition, and experiments at FWRF will explore approaches for improving pronghorn habitat evaluation techniques. Avian cholera causes tremendous annual losses in migratory waterfowl; experiments at FWRF will investigate relationships between environmental toxins and susceptibility to cholera in captive mallards. Use of pesticides �51 DRAFT to control crop damage presents a potential threat to upland game, birds and other species that reside in agricultural areas; experiments at rw~.F will augment field studies measuring the effects of common pesticides on various avian species inhabiting Colorado's farmlands. Through these and other projects, research activities at FWRF will provide scientific information to aid wildlife professionals in addressing management issues in Colorado and elsewhere. D. APPROACH Management of FWRF encompasses three broad operational activities: ANIMAL MAINTENANCE, FACILITY MAINTENANCE, and FACILITY IMPROVEMENT/EXPANSION. Each of these operational categories can be further subdivided into major programs, projects, activities, or emphases (eg. FWRF ANIMAL MAINTENANCE includes both Nutrition and Health Maintenance Programs). This organizational structure forms a foundation for the following overview of strategies for managing FWRF operations during FY90-9l to FY94-95. Annual FWRF Work Plans will be completed by 1 April of the fiscal year prior to enaction (except in FY90-9l, when the annual plan will be completed by 31 July 1990). Study plans, project descriptions, and annual Work Plans will be appended to appropriate subsections as they become available. Ongoing assessment of FWRF operations will be included in annual Job Progress Reports. 1. ANIMAL MAINTENANCE A variety of mammalian and avian species will be maintained at FWRF for use in research experiments. Feeding and care of these captive animals constitute major expenditures in the FWRF operating budget. At present, over 60 head of hoofed stock (elk, pronghorn, bighorn sheep, mountain goat, and domestic cattle) and nearly 50 ducks (several species) are wholly or partially supported by FWRF. Under present space and labor constraints, numbers of wild and domestic ungulates that can be maintained at FWRF are approaching upper limits. Strategies for anticipating species and numbers of individuals required to support ongoing and upcoming research, for controlling growth of our captive herds, and for placing or otherwise disposing of surplus animals will be developed during FY90-9l to FY94-95. Upcoming research needs will be identified largely through CDOW's species management planning process, from which experiments will arise to address specific issues or problems. In addition, management experiments will be conducted over the next 3 years to develop more cost-effective husbandry practices for maintaining research herds at FWRF. Standard operating procedures for humane care and treatment of research animals will be developed by CDOW's Animal Care Committee in compliance with Federal Animal Welfare regulations. a. Nutri tional Maintenance Under current ad libitum feeding regimes for hoofed stock, all individuals are maintained in good to excellent body condition year round. However, in some cases animals are overconditioned, and these feeding regimes are also wasteful. Strategies will be developed for improving efficiency of feeding programs for hoofed stock. Candidate strategies include: a) use of alternative foodstuffs (eg. grass hay, �52 DRAFT cubed alfalfa, complete pelleted rations) to reduce waste; .b) modified feeders (eg. hay racks, self-feeders) to improve access to hay and minimize trampling losses; c) structural protection of feed from rain and snow to minimize weather-related waste; and d) approaches for dispersing feed to reduce competition and increase feeding opportunities for subdominant animals. Improvements on feeding efficiency will target reductions in both direct feed costs and indirect costs of labor associated with feeding and clean-up. Management: Overall, costs for feeding research animals at FWRF total nearly $23,000 annually under current management practices. Objectives of feeding program improvements are to reduce overall feeding costs by 10% for FY90-9l (based on FY89-90 costs), and to establish a refined standard feeding program by FY92-93. Compared to cost estimates based on feeding to meet calculated energy requirements of species currently maintained at FWRF (Appendix A), feed costs for ad libitum feeding appear 10-lS% higher than necessary to maintain healthy research animals. During FY92-93, standard operating procedures for FWRF's feeding program will be established. In addition to reducing expenditures for animal feed, workstudy and YCC employees will be hired for feeding and clean-up beginning in FY90-9l to reduce human resource expenditures. The feeding programs for captive waterfowl and upland birds will be included in overall FWRF management duties beginning in FY90-9l; those programs may also be modified after assessment. Research: Management experiments will be used during FY90-9l and FY9l92 to evaluate and compare aforementioned strategies for improving feeding efficiency. Study plans for these management experiments will be appended as they become available. Standard operating procedures for FWRF's feeding program will be based on results of management experiments. As an adjunct to management experiments and future FWRF management planning, a computerized system for recording data on feed consumption, tracking feed supplies, and projecting feed needs will be developed during late FY90-9l and early FY9l-92. A description of that system will be appended, along with annual evaluations and updates. b. Health Maintenance Maintaining research animals in optimum health represents another significant activity in FWRF operations. The primary emphasis of FWRF's herd health program is preventive management and medicine. Current strategies for optimizing health in ungulate herds include proper nutritional management (see above), routine vaccinations and health care (eg. hoof trimming, parasite control), regular health monitoring (at minimum, daily inspections and weekly weighing), prompt veterinary examination and work-up followed by treatment and/or isolation for sick individuals, necropsy and diagnostic work-up of dead animals, and modifications of husbandry practices and facilities to minimize or prevent health problems. Major health problems persisting in the face of FWRF's current herd health program include necrotic stomatitis in pronghorn and bighorn sheep, overconditioning in pronghorn and bighorn sheep, chronic wasting disease in elk, pasteurellosis in bighorn sheep, �S3 DRAFT and traumatic injuries facility design. in pronghorn that arise from inadequacies in Management: Over the next 5 years, development of FWRF's herd health program will be directed toward early detection of serious illness in research animals and improvement of animal health record keeping. The objective of these modifications is a 10% reduction in overall health maintenance costs by FY92-93. In FY90-9l, a formal system for daily animal health assessment and reporting will be devised, tested, and implemented. In late FY90-9l and FY9l-92 a computerized database for tracking animal health and weight performance will be developed. Additionally, accounting systems for tracking drug and veterinary supply inventories as well as health maintenance expenses will be established in FY9l-92 and FY92-93. These systems will be used in budgeting for veterinary care, and in evaluating husbandry and preventive medicine strategies to improve herd health management at FWRF. Research: Management strategies for specific health problems affecting captive wildlife at FWRF will be evaluated through planned management experiments. Preferred strategies will then be summarized in problemspecific management plans. A study of necrotic stomatitis treatment and management in pronghorn is planned for FY90-9l. Nutritional management of captive ungulates will be addressed as described earlier. The Chronic Wasting Disease Management Plan developed for FWRF in FY86-87 will be revised in FY9l-92. Ongoing pasteurellosis research in bighorns currently precludes plans for more intensive management of that problem. Experiments using alternative visual barriers in pronghorn pens to reduce injuries caused by fence collisions will be completed in late FY90-91. 2. FACILITIES a. MAINTENANCE Basic Utilities i. and Services During FY90-9l, standard operating procedures designed to provide basic utilities and services to FWRF at minimum cost will be developed and implemented. In particular, improved heating efficiency for buildings and water-conserving approaches for irrigating pastures need to be developed. Quarterly expenditures for utilities and services (eg. electricity, water, propane, trash removal) will also be analyzed. During FY9l-92. SOP's will be modified to further reduce utilities/services expenditures; the objective of this project is to lower utilities/services costs by 10% in FY9l-92 and establish a conservation-oriented approach for providing these to FWRF. b. Routine/Preventive Maintenance i. During early FY90-91, a system for identifying, prioritizing, scheduling, and completing routine/preventive maintenance tasks at FWRF will be developed in conjunction with a similar system for facility repairs; descriptions of these systems will be appended later. These systems will be implemented and evaluated during FY90- �54 DRAFT 91. Based on performance of the trial system, a modified system and standard operating procedure will be developed and implemented during FY9l-92. Analyses of expenditures for maintenance and repairs will be made during FY9l-92 and FY92-93. Those data will be used to identify recurrent repair problems that could be addressed through preventive maintenance. Specific objectives for this project are reduction of overall facility repair costs by 10% in FY93-94 and of routine/preventive maintenance costs by 10% in FY9495. c. Repairs i. 3. During late FY89-90, a system for identifying, prioritizing, scheduling, and completing repairs at FWRF will be developed in conjunction with a similar system for routine/preventive maintenance. (See above for further details.) The management goal of both projects is to minimize investment in unscheduled emergency repairs at FWRF by identifying problem areas and addressing needs through preventive maintenance and/or facility modifications. FACILITIES EXPANSION/ENHANCEMENT Major modifications in existing FWRF facilities (Fig. 1) required to accomplish research objectives and/or improve operational efficiency, effectiveness, and/or safety will be planned and budgeted for as individual projects. In general, individual projects requiring significant expenditures of human (> 40 worker-hours) and/or fiscal (> $200) resources will be planned. During FY90-91, a standard operating procedure for anticipating annual expansion/improvement projects will be implemented. Detailed project plans will be included in subsequent annual work plans for FWRF. These project plans will include: brief description of the need, blueprints, sketches, and diagrams where appropriate, scheduled starting and completion dates, and budget including calculated or estimated costs of - personal services or labor (including contracts), operating supplies and services (including materials, supplies, services), added utility costs (for facility maintenance only), reimbursable travel costs (if any), equipment, and total projected cost. A recent evaluation of FWRF operations and needs for facility improvements identified several areas requiring attention in FY90-91. Priority projects included the following: a. Improving drainage for west-side animal paddocks and alleyway. Planned completion -- 31 July 1990. (Details will be included FY90-9l FWRF Work Plan.) in �DRAFT b. Staining east-side alleyway. Planned completion -- 7 A~gust (Details will be included in FY90-91 FWRF Work Plan.) c. Rebuilding west-side alleyway. Planned completion -- Phase I, peripheral alleyways: 31 October 1990; Phase 2, central alleyway/isolation pen complex: 30 June 1990. (Details will be included in FY90-91 FWRF Work Plan.) d. Expansion of animal paddocks (Fig. 2). Planned completion -- 31 October 1990. (Details will be included in FY90-91 FWRF Work Plan.) e. Design and construction be appended.) of elk handling facilities. 1990. (Details will Other facility modifications under consideration for subsequent fiscal years (listed here in no particular order of priority) include redesign of feeding areas to improve accessibility and clean-up, revegetation of overgrazed pastures with grazing-resistant forages, development of a facility-wide landscape plan, expansion of upland and migratory bird facilities, and establishment of on-site laboratory facilities. Ongoing and upcoming research projects will also dictate needs for modifications and improvements at FWRF. Annual projects covered under FWRF's operating budget will be selected on the basis of human and fiscal resources available, and will be prioritized using the following criteria: human safety> animal welfare/safety> facility-wide benefits > project-specific benefits. Other projects may be accomplished with supplemental funding and labor provided by ongoing or planned research projects. All projects will be approved by the facility manager and the Research Facility and Animal Committee (RFAC) prior to initiation. E. SCHEDULE Fiscal Year 1990-95 Activity 1. Animal MaintenAnce a . ltatritianal Maint.c.an.ce i. .DewPlop a sywt_ for estimating animal food requirements o~ animal and type of feed. by specie. ii. Implement and improve above system. iii. Conduct manag_nt experiments iv. Develop computerized v. Develop and implement vi. Maintain vii. Estimete D. Health system projected for tracking feeding FWRF animals to illlprovefeeding feed use and needs. SOP. in reasonable annual efficiency. physical feed requirements condition. and budget. 90 Oct-Dec 90 .Jan 91-Jun Apr-Sep 92 91 Jul 92-Jun 93 Jul 90-Jun 95 Jan-Mar 91-95 MainteDAnCe i. Devise, impl.~t.. 4t\d teat. daily hf>alth ~uess~t 11. Conduct prepare manag_nt management experiments to improve h •• lth program, plans for specific health problema. iii. Develop iv. Jul-Sep Revise computerized Chronic system Wasting for tracking Disease Management health Plan. 151''11._. data. Jul 90-Mar 91 Sap 90-Jun 95 Apr-Sep 91 Jan-Mar 92 �56 DRAFT v. Develop vi. Use preventive medicine and health monitoring maintain FWRF animals in optimum health. vii. 1990-95 2. Facility Prepare computerized system annual health for drug/supply care cost estimates inventory. programs Apr-Sep 92 to Jul 90-Jun and budget. 95 Ja.'1-Mar91-95 Maintenance a. Basic Utilities and Services i. Develop and implement ii. Revise SOP to minimize iii. Provide minimum b. Routine SOP's to lower utilities utilities expenditures. expenditures. necessary basic utilities/services to FWRF at cost emphasizing resource conservation. or Preventive i. Implement ii. Improve 90 Jul 91-Jun 92 Jul 90-Jun 95 Jul 90-Jun 91 Jul 91-Jun 92 Jul 90-Jun 95 Jul 90-Jun 91 Jul 91-Jun 92 Jul 90-Jun 95 Maintenance and evaluate and modify Oct-Dec formal maintenance system and SOP. system. iii. Perform routine maintenance, emphasizing use of preventive maintenance to reduce unscheduled repairs. c. Repairs i. Implement ii. Improve and evaluate and modify formal repair system (see 2bi). system. iii. Perform routine repairs, emphasizing use of preventive maintenance to reduce unscheduled repairs. 1990-95 3. Facility Expansion/Enhancement a. Project 1. Improving drainage for west-side animal alleyway. (Detailed in FY90-91 FWRF Work Plan.) paddocks b. Project 2. Stur::'~g east-side FWRF Work Plan.) in FY90-91 alleyway. (Detailed and Jul 90 Aug 90 c. Project 3. Rebuilding west-side alleyway. (Detailed in FY90-91 FWRF Work Plan.) Phase 1: Peripheral alleyway replacement. Phase 2: Central alleyway/isolation pen reconstruction. Aug-Oct 90 Nov 90-Jun 91 d. Project 4. Expansion of animal paddocks (Detailed in FY90-91 FWRF Work Plan.) Jul-Mar e. Design and conduct additional and handling expanSion/enhancement facilities. ?rojects. 90 Jul 90-Jun 95 Planned improvements in operating efficiency of FWRF are intended to hold annual requirements for fiscal resources constant in the face of inflation :::..:.::-ing FY90-91 through FY94-9S. In the later portion of this S-year planning period, increasing costs for personal services are anticipate _0 be offset by lowered costs for animal maintenance and facility repairs as described above. �.) I DRAFT Budget Category {OIl Personal Services Permanent employee (WRT III) Temporary employees (vacant) Workstudy/YCC employees (vacant) FTE Requirements PFTE TFTE 1.0 0.5 Operating Supplies/Services Animal Maintenance Feed Veterinary supplies and care Facilities Maintenance Routine preventive maintenance Facility expansion/enhancement 7,500 3,500 ~ Total (21o) .Costs 61,000 1.5 $ 10,000 2,000 and repairs 3,000 5,000 20,000 (21u) $ Utilities 3,500 3,500 Travel (28) $ Expenses 500 500 (31) Capital $ Expenditures 2,500 2,500 TOTAL ESTIMATED AVERAGE ANNUAL BUDGET $ 87,500 G. LOCATION The CDOW FWRF is that part of the Colorado State University Foothills Campus known as the Wildlife Research Experimental Area, originally consisting of 44 acres located as follows: 6.6 acres in the SE 1/4 of the SE 1/4 Section 6; 16.4 acres in the SW 1/4 of the SE 1/4 of Section 6; 7 acres in the NE 1/4 of the NE 1/4 of Section 7; and 14 acres in the NW 1/4 of the NE 1/4 of Section 7, all in T7N, R69W, 6PM. Boundaries have been modified slightly by annexation of about 10 acres of the southeast corner of the original lease by the City of Ft. Collins. H. RELATED Federal FEDERAL PROJECTS Aid to Wildlife Restoration Projects W-153-R-4 and W-152-R-2. �58 DRAFT Appendix A Wildlife Researcher Dan Baker estimated feeding requirements for captive ungulates housed at FWRF using species-specific energy requirements and feedspecific energy availabilities. Estimated feeding costs per head for nonreproducing individuals of all 3 species are below estimated costs for FWRRF's current ad libitum feeding program. These estimates will be evaluated using management experiments at FWRF to develop a more efficacious and efficient program for feeding captive wildlife. GENERAL INPUT DATA ENERGY COST: 1. 2. 3. 4. S. Average year-round body weight (kg) Metabolic BW Basal Metabolic Rate (BMR) - 70 kcal/kg BW 0.7S/day Average daily metabolis rate (ADMR) - 140 kcal/kg BW 0.7S/day Gestation Cost: First trimester: 1.35% x BMR 11.89% x BMR Second trimester: Third trimester: 42.32 x BMR 6. Lactation cost: First month: 1.5 x BMR 2.0 x BMR Second month: Third month: 1.5 x BMR 7. Conception date 8. Gestation period 9. Parturition date 10. Weaning date INTAKE 11. 12. (b/day): Grass hay intake - 1.84% x BW Alfalfa hay intake 1.95% x BW ENERGY CONTENT 13. 14. 15. (ME kca1/g): Grass hay - 1.9 Alfalfa hay - 2.2 Supplement - 2.4 - 2.9 depending on species FEED COST: 16. 17. Hay $lOO/ton Supp1 - $2S0/ton It is assumed requirements Requirements supplement. prevent them that all animals will eat to fill on hay diets. If total are met by this intake, then no supplement is consumed. not met by hay intake will be met by the consumption of Animals are supplemented only when fill limitations of hay intake from meeting ME requirements. �59 DRAFT PRONGHORN DATA INPUT: Ave. year-round boy weight - 46 kg MEW - 17.7 BMR - 1239 kcal/day ADMR - 2476 kcal/day Suppl - 2.4 ME kcal/g Ave. conception date - Sept. 15 Ave. gestation period - May 22 Weaning date - Sept. 1 1. Hon-pregnant Adult. ME Requirements ~~~~_~~~~!"_~ __i~~~y_l ___________ ~c~~j_~~y Month _ Grass Suppl ~~6 ~~~ ~~_7 ~~_1 kg/animal/yr 309 120 327 77 lbs/animal/yr 679 264 720 169 $$$/aniaal/yr 34 33 36 21 ADMR ___ ~!~_][~ Total ~~~_1_~~ ~~~_1_~~ Alfalfa Suppl _ TOTAL 2. Reproducing female. _______ ~__ ~':~~=:~-=~~~ __~c:~L~~~L Month Maint Gest Lact !.':.~~~!! __ (_g.L~!YJ Total Grass Suppl _ Alfal Suppl Jan 2476 147 0 2623 846 391 851 384 Feb 2476 147 0 2623 846 391 851 384 Mar 2476 523 0 2999 846 548 851 540 Apr 2476 523 0 2999 846 548 851 540 May 2476 523 0 2999 846 548 851 540 Jun 2476 0 1728 4204 846 1103 851 1043 Jul 2476 0 1728 4204 846 1362 851 1043 Aug 2476 0 1728 4204 846 1103 851 1043 Sep 2476 0 2492 846 330 897 329 (birth) 16.7 (wean fawn. and breed f••• le.) Oct 2476 16.7 0 2492 846 330 851 329 Nov 2476 16.7 0 2492 846 333 851 329 0 2623 ----- ---- ----- ---- ----- ---- ----- ----------- -----846---- -----333---- ----- ---- ----- ----Dec 2476 147 851 384 TOTAL kg/anima1/yr 309 222 311 210 lbs/animal/yr 679 488 683 462 $$$/aniaal/yr 34 61 34 58 Averaqe annual cost per head (nonreproducinq): $ 57.00 �DRAFT 60 Current estimated cost of ad libitum feeding: MOUNTAIH $ 74.00 SHEEP DATA INPUT ,: Ave. year-round body weight 90 kg MBW = 29 BMR = 2030 kcal/day ADMR = 4066 kcal/day Suppl. = 2.8 ME kcall/g Ave. conception date = Nov 15 Ave. gestation epriod 177 days Ave. parturition date = May 10 Weaning date = Sept 1 1. Hon-pregnant Adults ME Requirements !_~=? __~~~~~_~__i~~~X_l ___________ ~_c~~j_~~x _ Month ADMR Total Grass Suppl Alfalfa Suppl All yr 4066 4066 1656 275 1755 604 100 640 27 lbs/animal/yr 1330 220 1409 58 $$$/animal/yr 66 28 80 7 7 TOTAL kg/animal/yr 2. Reproducing females .!.z:t:~~= __(_g..L~~.¥ J______________ _______~ __ ~~~ ~.::;n~~~= __(_~c:.~j_<!.~X.L ____________________ Month ADMR Gest Lact Total Grass Suppl Alfal Suppl Jan 4066 484 0 4550 1656 448 1755 246 Feb 4066 484 0 4550 1656 448 1755 246 Mar 4066 1720 0 5786 1656 890 1755 687 Apr 4066 1720 0 5786 1656 890 1755 687 May 4066 1720 0 5786 1656 890 1755 687 Jun 4066 0 3045 7111 1656 1363 1755 1161 Ju1 4066 0 4060 8126 1656 1725 1755 1523 Aug 4066 0 3045 7111 1656 1363 1755 1161 Sep 4066 0 0 4066 1656 275 1755 73 Oct 4066 0 0 4066 1656 275 1755 73 Nov 4066 0 0 4066 1656 275 1755 73 (birth) (wean) (conception) 83 4066 27 4093 285 1755 0 1656 -----Dec---- -------- ----- ---- ----- ----------- -------- ----- ---- ----- ---- ----- ----TOTAL kg/anima1/yr 604 274 640 201 �61 DRAFT lbs/animal/yr 1330 ~$~$~$~/~a~n~ia~a~1~/~y~r~ 6~6~ 603 1409 ~7~5 70 Average annual cost per head (nonreproducing): $ 87.00 Current estiaated cost of ad libi~um feeding: $ 96.00 442 55 �DRAFT 62 DATA INPUT: Ave. year-round body weight 229 kg MBW = 58.8 BMR = 4136 kca11jday ADMR = 8272 kca1jday Suppl = 2.4 ME kca1jg Ave. conception date = Sept 15 250 days Ave. gestation period Ave. parturition date = June 1 Weaning date = Sept 1 1. Hon-pregnant Adult. ME Requirements ___________ !_c~}j_~~x ~~~ __~~~~~_e i~~~X_l Alfalfa Suppl o 4466 o 1538 0 1630 0 lbsjanimaljyr 3384 0 3586 0 $$$/animal/yr 169 0 179 0 Month ADMR Total Grass All yr 8272 8272 4214 kgjanima1jyr Suppl _ TOTAL 2. Reproducing females _______ ~ __z:~~~E:~_=~!__:J __C~c:~j_~~~L_____________________ !.~t:~~= __(_gl~~XJ _______________ Month Maint Gest Lact Total Grass Suppl Alfal Suppl Jan 8272 490 0 8762 4214 157 4466 0 Feb 8272 490 0 8762 4214 157 4466 0 Mar 8272 1742 0 10014 4214 679 4466 80 Apr 8272 1742 0 10014 4214 679 4466 80 May 8272 1742 0 10014 4214 679 4466 80 Jun 8272 0 6174 14446 4214 2525 4466 1926 Jul 8272 0 8232 16504 4214 3383 4466 2783 Aug 8272 0 6174 14446 4214 2525 4466 1926 Sep 8272 56 0 8326 4214 0 4466 0 (birth) (wean fawns and breed females) Oct 8272 56 0 8328 4214 0 4466 0 Nov 8272 56 0 8328 4214 0 4466 0 8272 0 490 0 8762 4214 157 4466 -----Dec ---- -------- ----- ---- ----- ---- ----- ---- ----- ---- ----- ---- ----- ---- ----- - - --TOTAL kgjanimaljyr 1538 328 1630 206 Ibsjanima1jyr 3384 722 3586 454 $$$/aniaal/yr 169 90 179 57 �63 DRAFT Average annual cost per head Current estiaated (nonreproducing): cost of ad libitum feeding: $179.00 $265.00 ��65 Colorado Division of Wildlife Wildlife Research Report July 1990 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~_ Project No. w-lS3-R-3 Work Plan No. ~l~A~ Job No. _ 3 Period Covered: Author: Mammals Research Multispecies Investigations Mammals Research Administration July 1, 1989 - June 30, 1990 R. B. Gill Personnel: R. B. Gill, L. E. Lovett, L. H. Carpenter ABSTRACT Progress towards the objectives of this job include: 1. Since June 1, 1989, I assumed temporary superv1s1on of all personnel affiliated with the Mammals 1 and Mammals 2 Research Sections, including 11 Wildlife Researchers, 1 Senior Secretary, and 1 Publications Specialist. I also assisted in the supervision of 1 Wildlife Research Technician. 2. During Fiscal Year 1989-90 a Final Draft of a Statewide Black Bear Management Plan was completed, reviewed, and published. Management activities necessary to implement the plan were initiated. ��67 MAMMALS RESEARCH ADMINISTRATION R. Bruce Gill P. N. OBJECTIVES Administer research within the Mammals productivity at the lowest cost. Research 2 Unit for the highest SEGMENT OBJECTIVES 1. Assign and supervise the research 2. Assign and supervise secretarial 3. Lead the development, management plans. of 6 Wildlife and clerical implementation, Researchers. work of 1 Senior Secretary. and evaluation of statewide species RESULTS AND DISCUSSION Objective 1. From June 1, 1989 through June 30, 1990, I was temporarily assigned responsibility for supervising the research activities of both the Mammals 1 and Mammals 2 Research Sections. Duties included directing and evaluating the work performance of 11 Wildlife Researchers, 1 Senior Secretary, and 1 Publications Specialist. During this period 11 manuscripts either were published or accepted for publication in peerreviewed journals. In addition, 2 manuscripts were accepted for publication in symposia proceedings. Drafts of Standard Operating Procedures were prepared to guide Division activities in management of mule deer, wapiti, black bear, mountain sheep, mountain goat, pronghorn, and puma. State Personnel Department's Performance Evaluation for Colorado (PACE) Performance Evaluation and Performance Planning Documents prepared for each Mammals 1 and Mammals 2 employee. Employees were Objective 2. A manual was prepared and updated continually regarding Standard Operating Procedures for accounting, purchasing, temporary personnel recruitment, and activities reporting. Four consecutively revised drafts of a black bear management plan were prepared and submitted for review and comment by DOW employees and interested organizations and concerned individuals. The Mammals Research Section Secretary received training with the most recent update of WordPerfect word processing software (WP 5.1) and documents were upgraded to WP 5.1 format. Budget status reports were prepared and sent to Wildlife Researchers quarterly for the period July 1, 1989-March 31, 1990. Budget status was reported monthly for the period April 1-June 30, 1990. �68 Objective 3. 1990-1995 necessary A final draft of the Division's Black Bear Management Plan was completed, reviewed, and published. Management activities to implement the plan were initiated. Work was begun on the preparation Plan. of a statewide LITERATURE Furbearer CITED Gill, R. B., and T. D. I. Beck. 1990. Black bear management Div. Wildl. Div. Rep. No. 15. 44p. Prepared S5 by: ~~~ R. Bruce Gill Wildlife Research Leader Management plan. Colorado �Colorado Division Wildlife Research July 1990 of Wildlife Report JOB PROGRESS REPORT State of Colorado Project No. W-lS3-R-3 Work Plan No. J~~. 4 Period Covered: Authors: Personnel: ~l~A~ Mammals Research _ Multispecies Wild Ruminant Investigations Forage Selection Dynamics July 1, 1989 - June 30 1990 B. J. Maynard P. N. Lehner, M. W. Miller, M. A. Wild, S. Roberts, R. B. Gill ABSTRACT Wavelength perception trials continued in the Y-maze. A successful research protocol for testing pronghorn visual perception has been established. A scotopic sensitivity curve for the pronghorn eye was generated using electroretinography. ��~, I.L WILD RUMINANT FORAGE SELECTION DYNAMICS Barbara J. Maynard P. N. OBJECTIVE To evaluate the role of v~s~on in diet selection foraging ruminant--the pronghorn. of a small, selectively SEGMENT OBJECTIVES 1. Conduct experiments concerning light wave-length and behavioral responses to light cues. sensitivity of pronghorns METHODS AND MATERIALS Wavelength perception trials continued in the Y-maze following the protocol outlined by Maynard (1989). A few changes were made in this protocol. The decision was made in December, 1989, to concentrate work on 1, rather than 6, pronghorn at a time; 1 male (ZO) was run daily from December, 1989, through June 1990. This male was fed alfalfa hay ad libi~, but was deprived of pelleted food except when he completed a run through the maze. For each trial, the male was led into the Y-maze and allowed to choose between 2 arms which differed only in the presence or absence of a light cue. A positive response to the light-off cue was rewarded with food and immediate release. A positive response to the light-on cue was punished with no food and 1 minute of confinement in the arm. Learning of this association and, therefore, perception of the light cue, was considered to have been demonstrated by a response level significantly better than would be expected due to chance; that is, entering the light-off arm at least 17 out of 20 trials (p $ 0.05). The number of trials run per day was determined by the animal's behavior. Trials were terminated when the animal was slow to re-enter the Y-maze for the next trial. Experience has shown this hesitancy to be predictive of lack of attention to the light cues. Number of trials run per day varied between 1 and 7. The initial training cue was white light emitted from a 100 W incandescent bulb through a I-inch hole in the end wall of the Y-maze arm. Once ZO demonstrated an ability to discriminate white light from no light, the cue was narrowed in wavelength to 10 nanometer (nm) bandwidths by the insertion of narrow bandpass filters in front of the light source. Again, perception of the light cue was accepted when ZO correctly responded during 17 of 20 trials. RESULTS AND DISCUSSION ZO reached the successful performance criterion of 17 correct choices out of 20 trials with light cues of white, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, and 850 nm wavelengths. Trials in which no light cue was presented were then run as a check to confirm that ZO was indeed responding to the light and not to some other unknown cue. ZO got 15 of 20 light trials �72 "correct." Such a high level of correct performance suggested the presence of an additional cue which "told" ZO which arm of the Y-maze was the "correct" choice. Odor was suspected as the additional extraneous cue. The introduction of an odor flooding procedure eliminated ZO's high performance on the no light trials. Wavelength trials are now being retested. Electroretinography (ERG) was performed on 4 castrated pronghorn from the Division of Wildlife's Foothills Wildlife Research Facility (FWRF). Dr. Steve Roberts, D.V.M., of Colorado State University's Veterinary Teaching Hospital Ir-----------------------------------------~ - I IJ .~~~~--_.--_.--~--~--~--._--~--~~ 1'0 400 .1 ••••••• It. II. A •• ,. N •• 70 700 710 W••••••• tII (_) Fig. 1. Pronghorn retinal responses to electroretinographic stimulation at varying wavelengths of light. �73 performed the ERG, and Dr. Mike Miller, CDO~ Research D.V.M., administered the anesthesia. The ERGs suggest that the pronghorn eye under scotopic (darkadapted) conditions is sensitive to a range of light wavelengths (Fig. 1). The shape of the pronghorn spectral sensitivity curve is typical for mammalian eyes (Horn and Lehner 1975, Hope and Bhatnagar 1979). Photopic (lightadapted) sensitivity curves are generally the same shape as scotopic curves, but are shifted to the right along the X-axis about 50 nm (Coren et al. 1984). LITERATURE CITED Coren, S., C. Porac, and L. M. ~ard. 1984. Sensation ed.). Academic Press, Inc. New York, NY. Hope, G., and K. P. Bhatnagar. 1979. spectral stimulation: comparison Experientia 35:1189-1191. Horn, S., and P. Lehner. 1975. 1atrans. J. Compo Physio1. Prepared by and perception (2nd Electrical responses of bat retina of four microchiropteran species. Scotopic sensitivity Psych. 89:1070-1076. in coyotes, Canis to ��75 Colorado Division of Wildlife Wildlife Research Report July 1990 JOB PROGRESS REPORT State of Colorado Project No. W-1S3-R-3 Work Plan No. Job No. _ 5 Period Covered: Author: -=lA~ Mammals Research Multispecies Consulting Analysis Investigations Services for Mark-Recapture July 1, 1989 - June 30, 1990 G. C. White Personnel: R. B. Gill, R. M. Bartmann, T. D. I. Beck, A, Neal, D. Reed ABSTRACT Progress towards the objectives of this job includes: 1. A manuscript summarizing the results of the Piceance Basin deer population studies has been developed, with publication intended as a Wildlife Monograph of The Wildlife Society. 2. A study of compensatory effects of harvest on the Piceance Basin mule deer population has been initiated, with the first experimental harvest in December, 1989. Radio collars to monitor over-winter survival of fawns were placed on the animals during November, 1989. 3. A Monte Carlo simulation study to evaluate mark-resighting methods estimate mountain sheep numbers was completed and manuscripts are currently undergoing peer review. . 4. Consultation has been provided in the design and analysis of markrecapture methods to estimate cray' fish population size. 5. A manuscript has been prepared on evaluating various methods to compute confidence intervals for age and sex ratio data from mule deer and elk. The manuscript is currently undergoing peer review, and is intended for submission to the Journal of Wildlife Management. 6. An interactive interface has been developed for the trapping and marking database in dBase 111+. The user is able to enter data, and to interrogate the database for potential radio frequencies or neck collar colors that could be used in a specified geographic area. 7. A model of a Colorado black bear population has been developed and used to simulate various experimental harvest strategies. A manuscript is currently being prepared for submission to the Journal of Wildlife Management. to ��77 CONSULTING SERVICES FOR MARK-RECAPTURE ANALYSES Gary C. White P. N. OBJECTIVES Model and s i mu La t e population estimates of deer, elk, mountain mountain goats with mark-recapture methods. sheep, and SEGMENT OBJECTIVE Evaluate mountain the joint hypergeometric sheep population size. maximum likelihood population estimator for RESULTS AND DISCUSSION Mark-resight is one procedure to estimate the size of mountain sheep (Ovis canadensis canadensis) populations. This method involves first capturing and marking animals. Subsequently, 1 or more sighting surveys identify and count marked and unmarked animals to provide an estimate of the proportion of the population that is marked, and thus the population size (Rice and Harder 1977, McQuivey 1978, Leslie and Douglas 1979). Mark-resight is based on mark-recapture with a Lincoln-Petersen estimate. Several assumptions of this method must be satisfied to estimate abundance accurately (i.e., without bias and with good precision) (Otis et a1. 1978). First, the population must be closed demographically and geographically. Second, animals must not lose their marks. Third, all marked animals must be correctly identified, counted, and recorded. Fourth, all animals (both marked and unmarked) must have the same, independent probability of being captured or of being sighted during an individual sighting occasion. Violations of these assumptions may result in an estimate that is biased, imprecise, or both. In reality, several of these assumptions may be violated during a survey. If animals form more or less stable social associations, the probability of sighting 1 animal is no longer independent of the sighting probability of another animal, and samples are no longer random. Likewise, some animals are more likely to be sighted than others due to behavioral differences (White et al. 1982), and sighting probabilities will be different. After the initial marking session, each sighting occasion results in a separate Lincoln-Petersen estimate. These individual estimates must be combined to obtain 1 overall population estimate, and the estimator chosen affects the accuracy of the estimate. The joint maximum likelihood estimator formed from the combination of 2 or more hypergeometric distributions (Chapman 1951, Seber 1982:130, Seber 1986), or JHE (Bartmann et al. 1987), possesses the optimal properties of any estimators to combine all the individual estimates. This estimator and the associated profile likelihood confidence interval has advantages over the mean or median of the estimates from each sighting occasion: the variance is smaller; the lower confidence bound in never lower than minimum number alive; and the confidence interval width is narrower (Bartmann et al. 1987, White and Garrott 1990:265-6). JHE of mark- �78 resight is the value of maximized: N which maximizes the following likelihood (ll) (1) 5i.(N and the terms are defined for all i = 2 to k+l number of sightings. The estimate of II can be found by iterative numerical methods. Program NOREMARK has been developed by us to run on an IBM PC or compatible to perform these computations. The effectiveness and dependability of mark-resight methods have been questioned (Furlow et al. 1981, DeYoung 1986, DeYoung et al. 1989). Visibility bias can lead to erroneous population estimates (Pollock and Kendall 1987). Violations of the assumptions of mark-resight may affect the estimator. To date, few studies have mathematically assessed the extent of problems inherent in the mark-resight method. we simulated mark-resight population estimation using JHE to evaluate the precision, bias, and coverage of this estimator with known population sizes. we tested the robustness of JHE to violations of the assumptions of independent and equal sighting probabilities (assumption 4). In addition, we tested JHE when sighting probabilities change between sighting occasions. within each simulation, we examined different population sizes, different number of sighting occasions, and different capture and sighting probabilities to observe possible influences on JHE. Given these four variables, we checked the predictability of the precision and bias for a proposed study. Simultaneously, helicopter surveys of a mountain sheep population in south central Colorado were used to estimate heterogeneity sighting probabilities and group information. METHODS Aerial Surveys and Study Area Field research estimated capture probabilities and sighting probabilities of mountain sheep across multiple resighting occasions, probability distributions for these sightings, average group size, and frequency of aggregation. Markresight surveys took place at Trickle Mountain, 38°09'N l06°20'w, Saguache County, Colorado. Using drop nets, net guns, and capture guns, 25 adult ewes were radio collared in January, February, and March, 1988. Only ewes were collared to avoid potential differences in sighting probability or behavior between age or sex classes, so that heterogeneity of sighting probabilities represents within age/sex class variation. Each collar was uniquely marked for visual identification, with unique radio frequencies in the range 172-173 MHz. Intensive helicopter resightings occurred on 15 occasions in January and February, 1989. To minimize differences between flights, the same 2 observers and pilot were used for all flights, the same seating arrangement was maintained, all surveys took place in the morning between 0800hr and l200hr, �79 and the flight plan was identical from flight to flight. An area was chosen where animals had been previously located and where all the animals were thought to remain during the winter; thus geographic closure was met. When a group was spotted, the location was noted, and the animals were followed and counted, carefully scrutinized for marks, and collars visually identified. Afterward, the helicopter returned to the original flight path. In addition, information was collected on ages, sexes, and reactions of the animals, distances at which groups were sighted, habitat types, and percent snow and cloud cover. The flight path was unidirectional and non-overlapping to avoid counting groups twice. Because of logistic and weather restrictions, pairs of flights were flown on consecutive days 6 times, and 3 flights flown on 3 consecutive days 1 time. After each survey, a verification flight with a telemetry receiver documented which marked animals were off the study area during the survey, which marked animals were not seen but were on the study area, and which marked animals had died. During verification, visual sightings were attempted for marked animals off the study area to expose all animals to the same treatment which may have occurred if the animals had been on the study area. Weather variables were fairly constant in these periods and were not considered a confounding factor. Animal locations during the survey and during the verification were plotted on maps following the flights. In the analysis of group information from the aerial surveys, all pair-wise combinations of marked animals in each group were considered; a proportion of the total flights where 1 animal was seen in association with 1 other animal was calculated. The maximum number of times 1 of the 2 animals was seen was used as the denominator. These proportions account for when an animal was seen, but do not account for when an animal was alone, when an animal was the only marked animal in the group, or group size. Maximum likelihood logistic regression tests were used to detect differences in sighting probabilities between individuals, differences in comprehensive sighting probabilities between flights, and possible interactions of the sighting probabilities among the animals and the date of the flight. Maximum likelihood was used to estimate the parameters of the beta distribution that best fit the observed sighting probabilities. The Kolmogorov-Smirnov goodness-of-fit test was used to test the fit of theoretical distributions to the observed sighting probability distribution. Simulations The Statistical Analysis System (SAS) (SAS Institute 1985) was used for Monte Carlo simulations. For the basic set of simulations, population sizes of 50, 100, 200, and 500 were used with 5, 10, 15, and 20 sighting occasions, capture probabilities of 0.1, 0.3, and 0.5, and sighting probabilities of 0.1, 0.3, 0.5, and 0.7. To reduce sampling variation, 1,000 replications were performed for each of these 192 scenarios. Capture and sighting probabilities were assumed constant for each member of the population. For each simulation, the number of marked animals, and the number of marked and unmarked animals seen per flight were generated from a binomial distribution. An estimate was then derived using the JHE. The 95% confidence interval and its length were computed (modified from Hudson 1971) by finding the values of N less than and greater than the estimate for which the log likelihood value was greater than 2 units below the log likelihood value of the maximum; the confidence interval values were the next values above and below each of these values, respectively. The confidence interval length was the difference between the upper and lower confidence interval endpoints. The coverage of the true population size by the confidence interval was then determined (above, below, covering). �80 Several additional sets of simulations were conducted to evaluate the robustness of the estimator. The assumption of independent observations was tested by simulating a range of aggregations among marked animals. Group sizes ranged from 1 to 24; the group size distribution was determined from field data. Two sets were simulated with groups remaining intact for all occasions: sighting probabilities were a function of group size or were independent of group size. Second, the robustness of JHE to the violation of the assumption of equal sighting probabilities was tested by simulating a continuous range of heterogeneity of sighting probabilities of individuals. A symmetrical, bellshaped distribution of sighting probabilities was used. Third, sighting probabilities were changed through time: random changes between 0.05 and 0.95, exponential increase (e.g., sighting probabilities increase as animals become more tolerant of helicopters), and exponential decrease (e.g., animals become more helicopter shy). To evaluate the simulations, length (elL), and confidence as percent relative bias (PRB) , confidence interval interval coverage were used. PRB was estimated PRB (E(N) - N) x 100 (2) N where E(N) is estimated as the mean of the simulated estimates. Overestimation (E(N) > N) results when PRB is positive, and underestimation (E(N) < N) results when PRB is negative. Percent. en, (peIL) is the en, divided by the population size to allow across population size comparisons. Analysis of variance (ANOVA) was used to identify variables affecting the estimate for PRB and pelL. Logistic regression was used to identify variables affecting coverage. These analyses were performed for the basic simulations where all assumptions were met. For the simulations with violations of assumptions, PRB, pelL, and coverage were compared to those of the basic simulations through means, standard errors, and t tests. RESULTS Aerial Surveys Flights occurred in January and February, 1989 (Table 1). The number of marked animals in the area surveyed ranged from 14 to 23 of 25 animals. Time spent searching with 2 observers was approximately 2.6 min/km2 for 33.67 km2. Proportion of marked animals seen ranged from 0.35 to 0.86, with a mean of 0.57 (SO - 0.153). There was no difference (P - 0.208) between the proportion of marked animals seen between the first and the second day of each set of flights. Observed group size ranged from I to 43 (Figure 1) for all flights and verification flights. Mean group size was 6.3 (SO - 6.0) with a median of 4. There was no difference (f - 0.638) in group size between the first and second day of each set of flights. Some animals spent most of their time together, e.g., 3 were together for 10 of 11 flights where they were sighted. �81 Table 1. Statistics Date Jan 14 Jan 17 Jan 18 Jan 19 Jan 27 Jan 28 Feb 1 Feb 2 Feb 8 Feb 9 Feb 15 Feb 16 Feb 22 Feb 23 Mean collected on the Trickle Mountain _1 T· tli !!h Ih 25 25 25 25 25 25 25 25 25 25 25 25 25 25 22 21 21 20 20 20 22 18 23 18 20 17 20 21 9 11 14 11 10 9 19 8 13 8 14 6 13 17 40 63 66 57 52 61 87 46 63 30 69 35 51 57 sheep population. Chapman Estimate 93.3 116.3 97.3 100.5 100.2 129.2 100.2 98.2 108.7 64.4 97.0 9l. 6 77 .0 69.9 79.6 30 25 20 >u ~ OJ ~ 15 0" OJ ,_, n T! ~ 10 5 o 1 3 5 7 9 11 13 Group 15 17 Slze 19 21 Figure 1. Frequency distribution of group sizes observed surveys and the verifications (hatched - survey, unshaded 23 28 43 during both the - verification). However, mostly the marked animals seemed to intermix fairly readily, and some marked individuals were never seen together. The number of times that 1 marked individual was sighted with another marked individual varied from 1 (0.083 of the total flights where an animal was sighted) to 11 (0.917 of the total flights where an animal was sighted). On average, 2 marked animals were �82 sighted together about 26.4% of the flights where they were seen together at least once and where at least 1 of the animals was seen. Because all marked animals were determined to be on or off the study area for each flight, a sighting probability for each marked animal could be calculated. Sighting probabilities for these 25 animals ranged from 0.33 to 0.86, with a mean of 0.58 (SD = 0.16) (Figure 2). A logistic regression model that included flights, animals, and their interactions demonstrated no significant differences in sighting probabilities between animals (P = 0.272) but there were significant differences between dates (P = 0.022). Specifically, a high proportion of marks (0.86) were seen on 1 February (flight #7) and a low proportion (0.33) were seen on 16 February (flight #12). When these dates were removed from the analysis, date no longer affected the sighting probability (P - 0.208). The beta distribution providing the best fit to the observed sighting probabilities has parameters a = 5.21 and = 3.75. Note that this fitted distribution will have a larger variance than the true sheep sighting distribution because the observed sighting probabilities include binomial sampling variation. a Based on a Kolmogorov-Smirnov goodness-of-fit test, the symmetrical, bellshaped beta distribution (a - 3, P - 3) used in the simulations fit the sighting probabilities from the field data (greatest difference - 0.16, reject at 0.38). The uniform distribution also fit, but not as well (greatest difference - 0.25). 7 0.28 ~ ~ 6 ro ~ ~ 5 ~ > ~ ~ 4 0.24 ~ ro ~ ~ ·rl > rl 0.20 ~ c ~ ~ G.16 x ~ ro 3 0.12 ~ ~ w ~ 2 8 ~ 0.08 r w c 'rl ~ 0 8 0 z 1 0 c 0 'rl 0.04 0.2 0.4 Sighting 0.6 D. 8 probabllity 1.0 ~ ~ 0 ~ 0 ~ ~ Figure 2. Frequency distribution of sighting probabilities for all marked animals. Circles indicate exact sighting probabilities; bars indicate groupings of sighting probabilities used in goodness-of-fit tests; the smooth curve is the best fitting beta distribution (a = 5.21, P = 3.75). Simulations A more complete summary of the simulations described here is presented in Neal (1990). Here, we present only general trends observed when the 4 parameters �83 of the simulations are summarized separately. In Neal (1990), the simulations are summarized for each of the individual scenarios. All Assumptions Met.--Precision of the estimator improved and bias decreased as true population size, number of sighting occasions, capture probability, or sighting probability increased. PRB was 1.04% with standard error 0.03 (Table 2), and ranged from -0.2 to 19.9% in the 192 scenarios. Low values of population size, number of flights, or capture or sighting probabilities caused poorer PRB (f < 0.001). Mean PCIL was 34.60% with standard error 0.32, and ranged from 2.0 to 12001.0%. As with PRB, scenarios with low population sizes, few number of flights, or low capture or sighting probabilities had greater PCIL (f < 0.001). Coverage was used to assess overall performance of the estimator. Percent coverage had a mean of 95.34% and ranged from 93.6 to 96.7%; percent of confidence intervals above the true population size ranged from 13 to 3.5%; and percent below ranged from 1.1 to 3.8%. Coverage with JHE is very good even with scenarios having low values of the 4 variables. With logistic regression procedures, neither popUlation size, number of flights, sighting probability, capture probability, nor any of their interactions affected coverage (P ~ 0.32). Apparently, coverage was not affected when all assumptions are met. Aggregations among animals.--With the groups intact for all sighting occasions and sighting probabilities independent of group size, PRB was 1.08% with a standard error 0.03 (Table 3), and ranged from -0.2 to 16.5%. PRB was not different between the basic simulations without groups and the group simulations. �84 Table 2. Percent relative bias (PRB) , mean percent confidence interval length (PClL), and coverage results for basic model simulations where all assumptions of the mark-resight estimator are satisfied. SE Subdivision PRB All variables 1.044 Population size 50 1. 766 100 1. 373 200 0.796 500 0.239 Number of flights 5 2.181 10 0.917 15 0.574 20 0.502 Sighting probability 0.1 3.065 0.3 0.745 0.5 0.264 0.7 0.101 Capture probability 0.1 2.025 0.3 0.754 0.5 0.351 SE PRB 0.029 Mean PClL 34.600 PClL 0.322 Coverage (%) Above (%) 95.345 2.291 0.081 0.068 0.046 0.025 53.008 41.386 27.764 16.242 1.015 0.754 0.204 0.074 95.317 95.352 95.285 95.427 2.273 2.273 2.360 2.258 0.092 0.053 0.040 0.033 60.468 32.126 24.823 20.982 1. 254 0.213 0.123 0.097 95.354 95.179 95.429 95.419 2.310 2.350 2.188 2.317 0.106 0.041 0.026 0.017 78.964 29.651 18.365 11.418 1.260 0.104 0.058 0.036 95.369 95.315 95.421 95.277 2.292 2.429 2.173 2.271 0.073 0.042 0.025 57.091 29.264 17.443 0.886 0.360 0.088 95.339 95.294 95.403 2.306 2.294 2.273 Table 3. Percent relative bias (PRB) , mean percent confidence interval length (PClL), and coverage data for simulations with the same groups remaining intact for all sighting occasions. SE Subdivision PRB All variables 1.097 Population size 1. 803 50 1.444 100 200 0.822 500 0.319 Number of flights 5 2.067 10 1.139 15 0.705 20 0.478 Sighting probability 0.1 3.168 0.3 0.647 0.5 0.224 0.7 0.349 Capture probability 0.1 2.013 0.3 0.905 0.5 0.374 SE PRB 0.031 Mean PClL 36.354 PClL 0.435 Coverage (%) 90.592 Above (%) 6.981 0.080 0.075 0.052 0.026 55.336 44.831 29.055 16.197 1.244 1.094 0.512 0.076 79.110 92.704 95.223 95.331 18.446 4.694 2.448 2.338 0.091 0.066 0.040 0.033 68.773 34.588 23.105 18.982 1.461 0.910 0.154 0.113 92.625 91. 056 89.838 88.850 4.860 6.427 7.862 8.775 0.113 0.043 0.023 0.014 92.712 28.331 15.941 8.433 l. 688 0.290 0.056 0.033 95.083 94.583 92 .146 80.556 2.481 2.881 5.323 17.240 0.076 0.046 0.027 60.240 31.402 17.420 1.127 0.592 0.262 90.739 90.802 90.236 6.739 6.816 7.389 �85 PClL had a mean of 36.35%, a standard error of 0.44, and a range over the 192 scenarios from 0 to 15935.0%. PClL was significantly lower for the basic simulations than for the group simulations. The main differences occurred in the number of flights, lower capture probabilities, and sighting probabilities. Percent coverage had a mean of 90.59% and ranged from 22.7 to 96.8%; percent of intervals above the true population size ranged from 1.1 to 76.5%; and percent below ranged from 0.6 to 3.9%. Coverage appeared to be much poorer when individuals were grouped than when they were not, as in the basic simulations. Percent below is similar to the basic simulations, but percent above was much greater; overestimation is the worse result of this increased variability. For a second set of simulations of aggregations among animals, sighting probabilities were a function of group size. In this set of simulations, mean sighting probability was 0.6 overall so a direct comparison between this and the previous simulations where Z sighting probability - 0.4 is not possible. PRB was 0.39% with a standard error of 0.02 (Table 4) and a range from -0.1 to 1.9%. While these values appear better than other simulations, when compared to the basic simulations with a similar interpolated mean between 0.5 (PRB = 0.26%, SE - 0.03) and 0.7 (PRB = 0.10%, SE = 0.02), these simulations with sighting probability a function of group size are more biased than simulations wi thout groups. Table 4. Percent relative bias (PRB), mean percent confidence interval (PClL), and coverage data for simulations where sighting probabilities by group size (Z sighting probability = 0.6). Subdivision PRB All variables 0.387 Population size 50 0.876 100 0.371 200 0.225 500 o.on Number of flights 5 0.411 10 0.405 15 0.331 20 0.403 Capture probability 0.1 O. rn 0.3 0.258 0.5 0.132 SE PRB 0.025 Mean PCIL 12.032 SE PCIL 0.046 Coverage {%2 78.425 Above {%2 12.529 0.061 0.059 0.046 0.029 14.546 14.511 11.616 7.454 0.116 0.100 0.073 0.041 70.833 80.625 80.900 8l. 342 21.858 9.958 9.150 9.150 0.061 0.051 0.045 0.043 18.635 12.126 9.417 7.950 0.124 0.078 0.060 0.051 88.383 80.325 74.742 70.250 6.833 11.617 14.458 17.208 0.061 0.037 0.024 18.873 10.724 6.499 0.094 0.060 0.036 78.862 78.894 n . 519 12.131 12.144 13.312 length differ PClL had a mean of 12.03%, a standard error of 0.05, and a range from 0 to 160.0%. When comparing these values with the simulations without groups at an interpolated mean of 0.6 between 0.5 (PClL - 18.36%, SE - 0.06) and 0.7 (PClL = 11.42%, SE - 0.04), pelL appears the same. Percent coverage had a mean of 78.42% and ranged from 55.2 to 91.2%; percent of confidence intervals above the true population size ranged from 4.3 to �86 34.2%; and percent below ranged from 3.2 to 15.8%. Coverage is worse here than with no groups or where groups have the same sighting probability regardless of their size. With smaller population sizes, overestimation becomes much worse. Heterogeneity of Individual Sighting Probabilities.--Heterogeneity of sighting probabilities of individuals was simulated from a symmetrical, bell-shaped, beta distribution (a = 3, P - 3). PRB had a mean of 0.60%, a standard error of 0.04 (Table 5), and a range of -0.18 (absolute minimum of 0.01) to 2.73%. These simulations had a mean sighting probability of 0.5. When compared to the basic simulations with constant sighting probabilities (PRB = 0.26%, SE 0.03), PRB with heterogeneity of sighting probabilities was significantly more biased than with homogeneity (f < 0.001). All variables made a difference, especially low capture probabilities. Table 5. Percent relative bias (PRB) , mean percent confidence interval length (PCIL), and coverage data for simulations with heterogeneity of individual sighting probabilities 0.5) . (R sighting probability Subdivision PRB All variables 0.595 Population Size 50 0.890 100 0.817 0.434 200 500 0.239 Number of flights 5 0.907 10 0.595 15 0.521 20 0.357 Capture probability 0.1 1.246 0.3 0.431 0.5 0.108 SE PRB 0.039 Mean PClL 18.701 SE PClL 0.064 Coverage (%} 78.852 Above (%) 10.267 0.102 0.090 0.067 0.041 25.997 22.113 16.429 10.265 0.142 0.139 0.102 0.057 79.267 78.892 78.583 78.667 9.842 10.125 10.417 10.683 0.094 0.076 0.073 0.069 27.998 18.844 15.094 12.868 0.174 0.107 0.085 0.071 88.992 81. 492 74.792 70.133 5.575 9.092 12.308 14.092 0.095 0.059 0.037 28.920 16.738 10.444 0.128 0.083 0.048 78.594 79.006 78.956 10.506 10.138 10.156 PCIL had a mean of 18.70% with a standard error of 0.06, and ranged from 3.0 to 207.0%. When compared to the basic simulations with constant sighting probabilities (PClL - 18.46%, SE - 0.06), the simulations with heterogeneity of sighting probabilities had significantly higher PClL (f < 0.001). The differences were greater with low population sizes, with all number of flights, and with lower capture probabilities. Percent coverage with heterogeneity of sighting probabilities had a mean of 78.8% and ranged from 68.4 to 90.4%; percent of confidence intervals above the true population size ranged from 4.5 to 16.4%; and percent below ranged from 3.9 to 17.9%. The increase in bias and decrease in precision with heterogeneity of sighting probabilities causes problems with confidence interval coverage. Sighting Probabilities Change with Time.--The last set of simulations involved simulating changes with time in sighting probabilities - random changes, exponential increase (helicopter tolerant), and exponential decrease �87 (helicopter shy). For random changes, our simulations had nondirectional changes with each flight with a mean sighting probability of 0.5 and were compared to the basic simulations with mean sighting probability of 0.5. PRB (mean - 0.09%, SE - 0.02) (Table 6) was similar to the basic sim~lations. With increasing sighting probabilities per flight, our simulations had a mean sighting probability of 0.6; PRB (mean = 0.20%, SE - 0.01) (Table 7) increased slightly. With decreasing sighting probabilities per flight, our simulations had a mean sighting probability of 0.4; PRB (mean = 0.44%, SE ~ 0.01) (Table 8) were similar to constant sighting probabilities if initial sighting probabilities were high. In other words, if sighting probabilities change with time, PRB will not be significantly worse as long as some of the flights have fairly high sighting probabilities. PCIL followed similar trends to PRB. With nondirectional changes with each flight, PCIL (mean ~ 12.92%, SE = 0.06) was similar to the basic simulations. With increasing sighting probabilities per flight, PCIL (mean = 14.96%, SE 0.02) also was similar to the basic simulations with constant sighting probabilities. With decreasing sighting probabilities per flight, PCIL (mean = 23.44%, SE - 0.02) could be lower if the initial sighting probabilities are very high. Coverage was also similar with changes in sighting probabilities and some high sighting probabilities than with constant: coverage with nondirectional changes was 95.3%; coverage with increasing sighting probabilities was 95.4%; and coverage with decreasing sighting probabilities was 95.4%. Table 6. Percent relative bias (PRB) , mean percent confidence interval length (PCIL), and coverage data for simulations where sighting probabilities for the population changes with each sighting occasion (R sighting probability - 0.5). Subdivision PRB All variables 0.087 Population size 50 0.070 100 0.156 200 0.100 500 0.022 Number of flights 5 0.276 10 0.094 15 -0.003 20 -0.019 Capture probability 0.1 0.305 0.3 0.021 0.5 -0.065 SE PRB 0.020 Mean PCIL 12.925 SE PCIL 0.055 Coverage (%) 95.252 Above (%) 2.002 0.052 0.046 0.036 0.021 17.426 15.202 11.707 7.365 0.136 0.122 0.092 0.050 96.017 95.267 94.375 95.350 l. 500 2.133 2.358 2.017 0.061 0.037 0.029 0.024 21.288 12.790 9.653 7.970 0.167 0.084 0.059 0.047 95.200 94.792 95.492 95.525 2.150 2.175 l. 950 1.733 0.048 0.031 0.019 20.026 11.606 7.144 0.120 0.077 0.044 95.406 95.269 95.081 2.050 2.000 l. 956 �88 Table 7. Percent relative bias (PRB) , mean percent confidence interval (PClL), and coverage data for simulations with sighting probabilities increasing with each occasion (z sighting probability = 0.6) . Subdivision PRB All variables 0.202 Population size 0.284 50 0.298 100 200 0.160 0.066 500 Number of flights 5 0.486 10 0.166 15 0.086 20 0.071 Capture probability 0.1 0.433 0.3 0.142 0.5 0.031 SE PRB 0.006 Mean pelL 14.956 SE pelL 0.017 Coverage (%} 95.376 Above (%} 2.228 0.016 0.014 O.Oll 0.007 20.409 17.690 13.335 8.392 0.042 0.039 0.028 0.016 95.510 95.340 95.278 95.377 2.059 2.243 2.362 2.247 0.020 O.Oll 0.009 0.007 25.951 14.593 10.666 8.616 0.050 0.025 0.018 0.015 95.351 95.297 95.404 95.454 2.224 2.265 2.233 2.190 0.015 0.010 0.006 23.125 13.417 8.327 0.038 0.024 0.014 95.368 95.356 95.406 2.240 2.241 2.202 Table 8. Percent relative bias (PRB) , mean percent confidence interval (pelL), and coverage data for simulations with sighting probabilities decreasing with each occasion (z sighting probability - 0.4). Subdivision PRB All variables 0.440 Population size 50 0.706 100 0.589 200 0.328 500 0.139 Number of flights 5 0.688 10 0.441 15 0.343 20 0.289 Capture probability 0.1 0.895 0.3 0.325 0.5 0.101 length length Coverage (%} Above (%) 0.024 95.432 2.243 32.868 27.681 20.490 12.726 0.057 0.054 0.039 0.021 95.413 95.390 95.451 95.474 2.213 2.262 2.241 2.256 0.023 0.018 0.016 0.015 30.599 23.852 20.692 18.623 0.065 0.046 0.039 0.034 95.397 95.445 95.466 95.419 2.213 2.232 2.236 2.291 0.022 0.014 0.009 36.174 20.990 13 .161 0.052 0.032 0.018 95.462 95.430 95.403 2.226 2.277 2.225 SE PRB Mean PClL 0.009 23.441 0.024 0.021 0.016 0.009 SE pelL DISCUSSION Mark-resight is one procedure used to estimate population size of mountain sheep. Several assumptions of this method may be violated in practice. Groups of Animals.--The assumption animals group together. Groups of precision but not as much as other simulations, groups of individuals of independent sightings can be violated if individuals affect the bias and the violations of assumptions. From our will not bias the estimate but, with low �89 sighting probabilities, the estimate will be more imprecise and coverage poorer. Rice and Harder (1977) also report an increase in variance of the estimate with increases in clumping. With populations of over 200, this increase in variability is minimal. Overestimation is a problem regardless of population size, number of flights, capture probability, or sighting probability. In reality, sighting probabilities are probably a function of group size, and from simulations with sighting probability differing by group size, the bias increases but the precision remains the same as in a population without groups. Coverage decreases so that overestimation is more of a problem with smaller population sizes, but both underestimation and overestimation are problems with larger population sizes. The Trickle Mountain data indicates that the animals do not tend to stay together for long periods of time. While information could not be obtained on group sighting probabilities, we expect that they vary with group size (Samuel et al. 1987). Consequently, we expect the estimates to be more biased than a population without groups, but not much more imprecise. Overestimation is our primary concern with the herd at Trickle Mountain. Heterogeneity of Sighting Probabilities.--Heterogeneity of sighting probabilities seems to affect the estimates more than violations of the other assumptions. White and Garrott (1990:264) suggest bias occurs with individual sighting heterogeneity. Our simulations show that heterogeneity leads to biased estimates, especially with smaller population sizes. The bias, however, is a maximum of 7.45% for one scenario; if this is a tolerable level, bias may not be a concern. More importantly, coverage tends to be too low and the estimates are more imprecise than the estimated confidence interval would suggest. With mountain sheep at Trickle Mountain, although the individual sighting probabilities range from 0.33 to 0.86, there is no significant difference among animals. Alternatively, the goodness-of-fit test indicates that a symmetrical, bell-shaped distribution fits the field data well. Precision and coverage are much poorer for data generated with a symmetrical, bell-shaped distribution than data generated with equal sighting probabilities; coverage can be as low as 68.4% (mean sighting probability of 0.5). Perhaps more flights or more animals would reveal if there are differences in the sighting probabilities of the animals at Trickle Mountain. For the populations where heterogeneity of sighting probabilities is a concern, greater sighting or capture probabilities would decrease the bias slightly and reduce confidence interval length. Sighting Probabilities Change with Occasion.--In addition to violations of assumptions, other sources of variation may have had an impact on the estimate: comprehensive sighting probabilities changing randomly with each flight, or sighting probabilities increasing or decreasing exponentially over time. When sighting probabilities change with each flight, the precision is greatly improved if sighting probabilities for some days are very high (e.g., ~0.95); if sighting probabilities are not high, then precision may be poorer. The bias is also lower than when sighting probabilities are constant, especially with fewer flights and smaller capture probabilities. Overall, even when some flights have high sighting probabilities, the coverage is lower and some underestimation is a problem. In the surveys at Trickle Mountain, the proportion of marks seen per day was variable but followed no particular pattern of increase or decrease. The population estimate and its associated variance are expected to be lower than actual values. We recommend concentrating effort to maximize the proportion of animals seen by methods such as choosing ideal weather conditions and using experienced observers. �90 The proportion of marks seen can also change with number of flights as animals become more or less habituated to the helicopter. When sighting probabilities increase with time, either the observers' abilities increased, the animals run more and are more visible, or the animals do not try to evade the helicopter and remain in the open. The estimates are slightly more biased but are not more imprecise than when sighting probabilities are constant. The resulting estimate would appear fairly precise but would be slightly biased. Maximizing sighting probability is important, so ideally flights should continue until sighting probabilities are high. When sighting probabilities decrease with time, the bias and variability may be lower than when a constant proportion of marks is seen if the initial sighting probability is very high. More flights and higher capture probabilities can improve the coverage slightly but the initial sighting probability is the main factor. However, the decrease in coverage in both these scenarios is minimal enough that these concerns could be disregarded. In the analysis of the field data, proportion of marks sighted do not follow a trend with time and there is no significant difference between consecutive flights or from the beginning to the end of the survey. Likewise, the group sizes do not change between consecutive flights. These results suggest that the sheep at Trickle Mountain are not becoming more or less habituated to the helicopter with time, nor are they reacting by changing group size. Population Estimate for Trickle Mountain Population The Trickle Mountain study area did not contain all the marked animals for all the sighting occasions, so the assumption of geographic closure was violated. Therefore, the estimator presented in Eq. (1) is not appropriate for this experiment. We have extended the estimator in Eq. (1) to include immigration/emigration through a binomial process. Assume that the total sheep population that has any chance of being observed on the study area is N*, and that at the time of the ith survey, Ni sheep are on the study area. We are interested in estimating the mean number of sheep on the study area, li, and possibly N*. At the time of the ith sighting occasion, a known number of the marked sheep (Mi) are on the study area of a possible Ii sheep with transmitters. The probability that an individual sheep is on the study area on the ith occasion can be estimated as Mi/Ii' Then the likelihood for the model that included immigration and emigration is a product of the binomial distribution for emigration/immigration times the joint hypergeometric likelihood of Eq. (1): The parameters N* and Ni for i-2 to k+l can be estimated by numerical iteration to maximize this likelihood, with the constraints that Ni > (Mi - fii + TIi) and N* > Nt for i-2 to k+l. Profile confidence intervals can be obtained for the k+l parameters. We were not interested in the k population estimates for each sighting occasion, but rather desired the mean of the Ni estimates. Therefore, we re-parameterized the likelihood to estimate the mean population size on the study area directly, and obtain its profile likelihood confidence interval. �91 For the data taken on the Trickle Mountain sheep population (Table 1), the total population (N·) was estimated as 120 (95% CI 109-133), with the average number of sheep on the study area estimated to be 96.1 (95% CI 88-106). These estimates seem reasonable because the minimum number of animals known to exist is 93 (66 unmarked sheep observed on 1 Feb flight, plus 25 marked sheep). Program NOR&~~ is available to perform these calculations. In theory, th~ estimator presented in Eq. (3) should be superior to the estimators presented by Eberhardt (1990) because it is a maximum likelihood estimator and hence is asymptotically minimum variance and consistent. However, Chapman (1951) demonstrated the bias of the maximum likelihood estimator for small sample sizes. Eberhardt's (1990) estimators are based on Chapman's estimator, which corrects the bias for situations where ill + ilz ~ N. Hence, for small sample sizes, his estimators may be appropriate, but the differences should decrease as population size increases. A second consideration is confidence interval construction. The profile likelihood intervals advocated here always generate a lower bound ~ to the minimum number of animals known alive. Other methods for constructing confidence intervals do not explicitly incorporate this logical lower bound. Finally, for poor quality experiments, 1 or more values of illi - O. Eberhardt (1990) refers to this problem as an infinite bias. For the 2 estimators presented here, if at least 1 illi > 0, the estimator will be defined and still produce a maximum likelihood estimate. Occasions with illi - 0 contribute information about population size, but not enough information to produce logical estimates. When these occasions are combined with the remaining occasions where illi > 0, a logical estimate can still be produced. If illi - 0 for all i, no logical estimate of N can be constructed, although an upper and lower probability bound can be constructed. The estimator described by Minta and Mangel (1989) should provide a method robust to heterogeneity of individual sighting probabilities. Although this estimator requires geographic closure, immigration/emigration from the study area can be viewed as a form of sighting heterogeneity and the estimator is still appropriate to estimate the total sheep population for the study area. The number of resightings for the 25 marked sheep were 1 with 2, 4 with 3, 2 with 4, 3 with 5, 4 with 6, 2 with 7, 2 with 8, 3 with 9, 2 with 10, and 2 with 12, giving 162 marks observed. For unmarked sheep, 615 were observed in the 14 flights. The program supplied by Minta estimates the population size as 95, with a 96.9% CI as 87-104. This estimate seems too low, given that the minimum number of animals known to exist is 93. Further, the lower confidence bound is less than this known quantity, and in general this confidence interval seems too narrow. The heterogeneity caused by immigration/emigration may cause this estimator to not perform well with these data. Design of Mark-Resight Experiments Two approaches are available to compute the sample size necessary for the thorough design of a mark-resight experiment. First, if the expected parameters of the experiment fall into the range of parameter values simulated in Neal (1990), linear interpolation can be used to evaluate elL and PRS from the tables presented there. Program NOREMARK has been developed to provide linear interpolations based on these simulations. Second, additional simulations can be conducted with parameters specific to the proposed experiment. Program NOREMARK can also perform these simulations, although the computer time required is considerably greater than for linear interpolation. �92 CONCLUSIONS We recommend mark-resight and the JHE as a population estimation method for mountain sheep where closure and a well-defined study area are available. The bias is low and the precision is good if all assumptions are met. We note that confidence interval length and coverage can be very poor with small population sizes, few flights, or low capture or sighting probabilities (e.g. Bartmann et al. 1987). The violation of the assumption of random samples (e.g. groups of animals) increases the bias and decreases the precision, but not as much as heterogeneity of sighting probabilities. The groups in the Trickle Mountain herd, however, are not generally large enough or dependent enough to be a large consideration in affecting an estimate. The violation of the assumption of equal sighting probabilities worsens the precision and the coverage more than with equal probabilities. From the Trickle Mountain data, heterogeneity of sighting probabilities may exist and needs to be considered as a factor decreasing the precision and the coverage. In all cases, increasing the sighting probabilities and increasing the number of flights have the most influence in improving the estimator; during flights, concentrated effort to achieve high sighting probabilities is most beneficial. LITERATURE CITED Bartmann, R. M., G. C. White, L. H. Carpenter, and R. A. Garrott. 1987. Aerial mark-recapture estimates of confined mule deer in pinyon-juniper woodland. J. Wildl. Manage. 51(1):41-46. Chapman, D. G. 1951. Some properties of the hypergeometric distribution with applications to zoological sample censuses. Univ. Calif. Publ. Stat. 1(7):131-160. DeYoung, C. A. 1986. Accuracy of helicopter Wi1d1. Soc. Bull. 13:146-149. surveys of deer in south Texas. _______ , F. S. Guthery, S. L. Beasom, S. P. Coughlin, and J. R. Heffelfinger. 1989. Improving estimates of white-tailed deer abundance from helicopter surveys. Wi1d1. Soc. Bull. 17:275-279. Furlow, R. C., M. Haderlie, and R. Van den Berge. 1981. Estimating a bighorn sheep population by mark-recapture. Desert Bighorn Council, Trans. 1981:31-33. Eberhardt, L. L. 1990. Using radio-telemetry for mark-recapture edge effects. J. Applied Ecology 27:259-271. Leslie, D. M., Jr., and C. L. Douglas. 1979. Desert bighorn River Mountains. Nevada. Wild1. Monogr. 66:1-56. studies with sheep of the ______ , and C. L. Douglas. 1986. Modeling demographics of bighorn sheep: current abilities and missing links. N. Amer. Wi1d1. Natur. Res. Conf. Trans. 51:62-73. McQuivey, R. P. 1978. Bio1. Bull. No.6. The desert bighorn 81pp. sheep of Nevada. Nevada Fish, Game �93 Minta, S. and M. Mangel. 1989. A simple population estimate based on simulation for capture-recapture and capture-resight data. Ecology 70:1738-1751. Otis, D. L., K. P. Burnham, G. C. White, and D. R. Anderson. 1978. Statistical inference from capture data on closed animal populations. Wildl. Monogr. 62:1-135. Pollock, K. H., and W. L. Kendall. 1987. Visibility bias a review of estimation procedures. J. Wildl. Manage. in aerial surveys: 51(2):502-510. Rice, W. R., and J. D. Harder. 1977. Application of multiple aerial sampling to a mark-recapture census of white-tailed deer. J. Wi1d1. Manage. 41(2):197-206. SAS Institute Inc. 1985. SASR Language Guide for Personal 6 Edition. SAS Institute Inc., Carey, N.C. 429pp. Computers, Version Samuel, M. D., E. O. Garton, M. W. Schlegel, and R. G. Carson. 1987. Visibility bias during aerial surveys of elk in northcentral Idaho. Wildl. Manage. 51(3):622-630. Seber, G. A. F. parameters 654pp. J. 1982. The estimation of animal abundance and related (2nd edition). Macmillan Pub1. Co., Inc., New York, N.Y. 1986. A review 292. for estimating animal abundance. Biometrics 42:267- White, G. C., D. R. Anderson, K. P. Burnham, and D. L. Otis. 1982. Capturerecapture and removal methods for sampling closed populations. Los Alamos National Laboratory. LA-8787-NERP. Los Alamos, N.M. 235pp. , G. C., and R. A. Garrott. 1990. Analysis of wildlife data. Academic Press, New York, N.Y. 383pp. Prepared by &n?J (: (:>j~. Gary C. Wh' e Associate Professor radio-tracking ��Colorado Division of Wildlife Wildlife Research Report July 1990 JOB PROGRESS REPORT State of Colorado Pro J ec t No. _W",--=-15~3~-....:R,",---,3==-_ Mammals Research Work Plan 2A Mountain Job No. 4 Experiments to Identify and Manage Stress in Mountain Sheep Period Covered: July 1, 1989 - June 30, 1990 Author: No. Sheep Investigations M. W. Miller Personnel: M. A. Wild, H. A. Petit, N. T. Hobbs, R. B. Gill, J. A. Bailey ABSTRACT Sampling procedures markedly affected (f < 0.0001) ability to culture Pasteurella spp. from bighorn sheep. Nonhemolytic f. haemolytica was isolated from 18/19 tonsillar swabs or biopsies from adult bighorns, but from only 4/19 nasal swabs. Nonhemolytic f. haemolytica was cultured from 14/19 tonsillar swabs plated directly, but from only 2/19 swabs stored for 24 hr in modified Amies with charcoal; f. haemolytica was not recovered from any of 19 swabs stored for 24 hr in modified Stuart's medium. Based on airect cultures of tonsillar samples, all 26 bighorns sampled were infected with f. haemolytica; 2 lambs developed pneumonia during this study. Tonsillar swabs or biopsies plated directly onto blood agar and incubated immediately offer the greatest probability of recovering nonhemolytic f. haemolytica from healthy bighorn sheep. Simulation modeling was used in preliminary evaluations of alternatives for managing disease cycles in bighorn populations. Epidemic disease caused simulated populations to display episodic increases and declines; disease-driven cycles repeated at 15- to 25-year intervals. Analysis of management scenarios, including several tactics for population and habitat manipulation, revealed that aggressive control of ewe numbers (e.g. harvest, trapping) was the most effective method for ensuring long-term stability and abundance in simulated bighorn populations. Simulations also indicated that short-term monitoring and/or comparison of asynchronous populations may be misleading in evaluating management practices. Modeling results suggested that relationships between density of bighorn populations and their susceptibility to disease, as well as effects of removal techniques (harvest, trapping) on sheep distribution, offer important unresolved questions in bighorn management. Environmental conditions may influence cortisol concentrations measured in bighorn feces. Fecal cortisol levels were affected by simulated environmental treatment (P ~ 0.0001) and exposure time (P ~ 0.0001); environment and time also interacted (P ~ 0.0001). For fecal samples held at 20 C, mean cortisol concentrations were about 2.7 times higher than controls held at -20 C after 2 days; a similar pattern emerged after cyclic freezing and thawing. Freezing at 20 C appeared to stabilize cortisol levels in bighorn feces for ~ 32 days. Influences of environmental conditions on measurable cortisol levels in bighorn feces could lead to misinterpretation of field data, and should be considered in applying these techniques to management studies of stress in bighorns. ��97 PLANE OF NUTRITION AND BIGHORN SHEEP POPULATION PERFORMANCE Michael W. Miller P. N. OBJECTIVE To treat bighorn sheep to control disease where necessary. SEGMENT OBJECTIVES 1. Develop a research strategy and proposal for managing viral diseases in mountain sheep populations. 2. Design population and management level experiments stress levels of mountain sheep populations. bacterial and to detect changes in Management of Bacterial and Viral Diseases in Mountain Sheep Populations Inability to control infectious disease outbreaks and subsequent mortality in mountain sheep populations represents a significant obstacle to long-term success in their management. Although the "bighorn pneumonia complex" has been studied intensively for over 3 decades, little is known about many aspects of its etiology and epizootiology. Moreover, management interventions recommended for preventing or controlling this problem remain untested. A research strategy and proposal for managing bacterial and viral diseases in bighorn populations will be developed over the next year as part of a statewide plan for bighorn management. However, improved and standardized methods for collecting and interpreting diagnostic data, along with innovative approaches for evaluating potential management tactics, appear prerequisite to developing and implementing such a research strategy. To this end, recent research has focused on improving tools available for use in management experiments that will be designed to study etiology, epizootiology, and prevention or control of disease outbreaks in bighorn populations: Epizootiology of Pasteurellosis (M. W. Miller and M. A. Wild) in Mountain Sheep Populations Pasteurellosis appears to be the primary component of most pneumonia outbreaks in bighorn populations. As part of our ongoing research efforts to improve understanding of the etiology and epizootiology of pasteurellosis in bighorns, we conducted and reported on a series of experiments evaluating techniques for detecting Pasteurella spp. infections in healthy bighorn sheep: Wild, M. A., and M. W. Miller. 1991. Detecting nonhemolytic Pasteurella haemolytica infections in healthy Rocky Mountain bighorn sheep (Ovis canadensis canadensis): influences of sample site and handling. J. Wildl. Dis. In Press. �98 ABSTRACT: Effects of sampling procedures on ability to culture Pasteurella spp. from Rocky Mountain bighorn sheep (Ovis canadensis canadensis) were examined experimentally. Sample site influenced (f < 0.0001) recovery of f. haemolytica in adult bighorn sheep. We isolated nonhemolytic f. haemolvtica from 18 of 19 tonsillar swabs and 18 of 19 tonsillar biopsies from adult sheep, yet only 4 of 19 nasal swabs yielded isolates. Sample handling also affected (f < 0.0001) recovery of f. haemolytica. Nonhemolytic f. haemolytica was cultured from 14 of 19 tonsillar swabs plated directly onto blood agar, but from only 2 of 19 swabs stored for 24 hr in modified Amies with charcoal; we failed to recover f. haemolytica from any of 19 swabs stored for 24 hr in modified Stuart's medium. We detected nonhemolytic f. haemolytica at least once in bronchial aspirates from 4 and in nasal swabs from 3 of 6 bighorn lambs. Based on direct cultures of tonsillar swabs and/or biopsies, all 26 bighorn sheep (7 lambs, 19 adults) sampled were infected with nonhemolytic f. haemolytica; only 2 lambs developed pneumonia during the study period. Thirty-four of 37 nonhemolytic f. haemolytica isolates tested were biotype T; 3 were biotype A. Serotypes 3; 4; 3,4 and 3,4,10 were identified in a subsample of 17 isolates. Our data suggest tonsillar swabs or biopsies plated directly onto blood agar and incubated immediately offer the greatest probability of recovering nonhemolytic f. haemolytica from healthy bighorn sheep. Managing Bighorn Population Cycles: A Simulation (M. W. Miller, N. T. Hobbs, and R. B. Gill) Approach As part of an adaptive environmental assessment exercise reported elsewhere (Hobbs et al., 1990), we developed a computer model that simulated disease and other natural processes influencing bighorn population performance. Using this model, we conducted simulation experiments to examine and compare management strategies for controlling disease outbreaks in a simulated bighorn herd. Results of these experiments will contribute to refined modeling approaches, which will be used in formulating research strategies and proposals for managing bacterial and viral diseases in bighorn populations. MATERIALS AND METHODS Simulation modeling was used in preliminary evaluations of alternatives for managing disease cycles in bighorn populations (see Hobbs et al., 1990 for details of the model and simulation experiments). This model was structured as a Leslie matrix with 2 sexes and 12 age classes, and was formulated such that natality and overwinter survival rates responded to changes in net primary production of forage and its availability. In addition, bighorn survival across all age classes was reduced by periodic disease epidemics, and parasitism also contributed to lamb mortality. Epidemic disease was assumed to be a stochastic processes mediated by animal density, and severity of parasitism was affected by both density and ewe condition. RESULTS AND DISCUSSION In the absence of epidemic disease, simulated bighorn populations showed exponential increase and asymptotic stability (Fig. 1); parasitism lowered the realized asymptote (Fig. 1). Epidemic disease caused simulated populations to display episodic increases and declines in bighorn abundance; these disease- �99 driven cycles repeated at 15- to 25-year intervals (Fig. 1). Analysis of alternative management scenarios, including several tactics for population and habitat management, revealed that population control (e.g. harvest, trapping) was the most effective method for ensuring long-term stability and abundance in bighorn populations. Although ram-only harvest preserved epizootic cycles, aggressive removal of both ewes and rams appeared to eliminate those cycles (Fig. 2). Simulations also indicated that short-term monitoring and/or comparison of asynchronous populations may be unreliable in evaluating efficacy of bighorn management practices. Modeling results suggest that relationships between density of bighorn populations and their susceptibility to disease, as well as effects of removal techniques (harvest, trapping) on sheep distribution, offer important unresolved questions in bighorn management. Detecting and Managing Stress in Mountain Sheep Populations Plans for designing and conducting management experiments to detect changes in stress levels of mountain sheep populations will proceed pending identification of suitable treatment and control herds for use in such studies. In the interim, we proceeded with development and evaluation of our techniques for detecting stress responses in bighorns: Effects of Environmental Variables on Cortisol Feces (H. A. Petit and M. W. Miller) MATERIALS Levels Measured in Bighorn AND METHODS We conducted an experiment to examine effects of simulated environmental variables (temperature, moisture, and UV light) over time on cortisol concentrations measured in feces from an ACTH-treated bighorn sheep. A pooled sample of bighorn feces (about 350 g) was equally divided into 93, 3.5 g aliquots. Aliquots were randomly assigned to 1 of 5 simulated environmental treatments (n - 18 aliquots/treatment): - constant freezing (-20 C). cyclic (12 hr) freezing/thawing (20 C/-20 C). constant room temperature (20 C). alternate-day soaking with deionized water (at 20 C). cyclic (12 hr) UV light exposure (at 20 C). Three additional aliquots were frozen immediately after collection and lyophilized for 24 hr to serve as absolute controls. On days 1, 2, 4, 8, 16, and 32 of treatment, we randomly chose 3 aliquots from each treatment group; these were frozen for 2 hr at -20 C, then lyophilized for 24 hr. All lyophilized samples were stored at -20 C until ground in a Wiley mill and prepared for fecal cortisol analysis as previously described (Miller et al. 1990). Cortisol was measured by radioimmunoassay, and cortisol concentrations were expressed as ng cortisol/g dm feces (Miller et al. 1990). We analyzed data by 2-way ANOVA (SAS, PROC GLM), with environmental treatment and time as main effects; we further examined effects of select environmental conditions using orthogonal contrasts. �100 RESULTS AND DISCUSSION Simulated environmental conditions had profound influences on measured fecal cortisol concentrations (Fig. 3). Preliminary analyses revealed that fecal cortisol levels were affected by environmental treatment (P ~ 0.0001), as well as exposure time (P ~ 0.0001); effects of environment and time were interactive (P ~ 0.0001). The most pronounced effects on measured cortisol occurred in fecal samples held at room temperature: within 2 days, mean cortisol concentrations from those samples were about 2.7 times higher than in frozen controls. A similar pattern emerged in samples exposed to cyclic freezing and thawing, although the changes were of smaller magnitude and peak response was delayed about 2 days. Freezing at -20 C appeared to stabilize cartisol levels in feces for at least 32 days. These results resemble those observed in an earlier experiment conducted before a reliable fecal cortisol assay had been developed (Miller and Hobbs, 1987). Patterns of change in measurable fecal cortisol levels observed here support our earlier hypothesis that bacterial and/or protozoal degradation of an undetected metabolite of cortisol, perhaps a sulfate or glucuronide, causes an increase in free cortisol levels in feces for 2-4 days after excretion. During this initial phase, the rate of converting cortisol metabolites to free cortisol may exceed degradation rates for free cortisol, whereas after 4-8 days cortisol degradation takes over. Because none of the samples were completely depleted of cortisol, we presume that bacterial and/or protozoal degradation of cortisol in excreted feces limited by time and is probably modified by temperature and moisture. We plan to conduct HPLCs on fecal extracts to gain further insights into the mechanisms driving this phenomenon. These assays should reveal presence of cortisol metabolites that may be contributing to observed elevations in measurable free cortisol. Ultimately, controlled incubation of fresh feces at room temperatures may provide a more sensitive estimate of total fecal cortisol excretion in stressed bighorns, thereby improving overall reliability of the assay. However, in the short term our results should serve to caution those intent on applying fecal cortisol data to solving bighorn management problems. The marked influences of environmental variation on measurable cortisol levels in bighorn feces could easily lead to misinterpretation of data collected under field conditions. Management decisions based on these data will be equally erroneous. LITERATURE CITED Hobbs, N. T., M. W. Miller, J. A. Bailey, D. A. Reed, and R. B. Gill. 1990. Biological criteria for introductions of large mammals: using simulation models to predict impact of competition. Trans. No. Amer. Wildl. and Nat. Res. Conf. (in press). Miller, M. W., and N. T. Hobbs. 1987. Bighorn sheep investigations: plane of nutrition and bighorn sheep population performances. Colo. Div. Wildl., Wildl. Res. Rep., Fed. Aid Proj. 01-03-048, WP2, J4, Job Prog. Rep., July 1986 - June 1987. Miller, M. W., N. T. Hobbs, and M. C. Sousa. 1990. Detecting stress responses in Rocky Mountain bighorn sheep (avis canadensis canadensis): reliability of cortisol concentrations in urine and feces. Can. J. Zool. In Press. �101 ~ild, M. A., and M. ~. Miller. 1991. Detecting nonhemolytic Pasteurella haemolytica infections in healthy Rocky Mountain bighorn sheep (Ovis canadensis canadensis): influences of sample site and handling. J. ~ildl. Dis. In Press. / I ,I Prepared by'. //"""/1 ,v,,#/7 ({I;' (/ K./ . ~ ,,/'~ ~ ~/ ...._./ --___ Michael ~. Miller ~ildlife Researcher ./ ��Colorado Division Wildlife Research July 1990 103 of wildlife Report JOB PROGRESS REPORT State of Colorado Project No. W-lS3-R-3 Work Plan No. ~2~A~ Job No. 6 Author: N. T. Hobbs Personnel: Mammals Research _ Mountain Sheep Investigations Adaptive Assessment Management-Simulations of CO-Management of Mountain Sheep and Mountain Goat Populations M. W. Miller, J. A. Bailey, D. F. Reed, and R. B. Gill ABSTRACT We constructed a simulation model to evaluate alternatives for' managing populations of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) and Rocky Mountain goats (Oreamnos americanus) and to examine the potential for competition between them. Our model was structured as a Leslie matrix for two species with 2 sexes and 12 age classes. We formulated the model such that natality and overwinter survival rates of both species respond to changes in net primary production of forage and its availability. Bighorn nllIT~~r5were also regulated by effects of epidemic and endemic disease, as well as lamb mortality caused by parasitism. We assumed epidemic disease and parasitism are stochastic processes mediated by animal density. Simulated bighorn populations disFlayed episodic increases and declines in abundance caused by disease epidemics. Disease-driven cycles repeated at 15- to 20-year intervals. Epizootic cycles were preserved when ram-only harvest was added to the simulation, but aggressive harvest of both ewes and rams appeared to eliminate those cycles. Simulated mountain goat populations showed classical exponential increase and asymptotic stability following introduction into new habitat. In the absence of management, mountain goats virtually el~minated bighorns from alpine ranges. Aggressive harvest of both goats and'sheep allowed both species to maintain stable equilibria. Benefit/cost analysis of alternative management scenarios, including several tactics for population and habitat management, revealed that harvest may be the only-cost effective action influencing long-term abundance and distribution of bighorn popUlations. Adding mountain goats to ranges occupied by an established bighorn population did not enhance benefit/cost ratios. We conclude that mountain goats can be introduced to habitats occupied by bighorn sheep without harming bighorn populations, provided both species harvested aggressively. However, we failed to find any economic incentive for such introductions. We suggest that relationships between density of bighorn populations and their susceptibility to disease, as well as effects of harvest on sheep distribution, offer important unresolved questions in bighorn management. ��105 ADAPTIVE ASSESSMENT MANAGEMENT - SIMULATIONS OF CO-MANAGEMENT OF MOUNTAIN SHEEP AND MOUNTAIN GOAT POPULATIONS N. Thompson Hobbs P. N. OBJECTIVES 1. To develop management an adaptive assessment management model to simulate alternative strategies with mountain goat and mountain sheep populations. 2. To develop statewide guidelines mountain goat populations. for co-management 3. Implement through management guidelines of mountain the planning/budgeting sheep and process. INTRODUCTION High mountain landscapes offer unusual recreational opportunity to the people of Colorado. In particular, many people who enjoy the Colorado mountains also value the chance to observe and hunt alpine ungulates, including Rocky Mountain goats (Oreamnos americanus) and Rocky Mountain bighorn sheep (Ovis canadensis canadensis). It is the mission of the Division of Wildlife to preserve and enhance that opportunity. Mountain goats are probably not indigenous to Colorado, but were successfully introduced into several of the state's mountain ranges during 1948 to 1971. Currently, Division of Wildlife policy prevents further transplanting of mountain goats into Colorado because it is widely believed that they may compete with native populations of bighorn sheep for limited areas of suitable high elevation habitat. Bighorn sheep populations have performed poorly in many areas of Colorado, and hence it is wise to avoid actions that might further restrict in their distribution and abundance. However, policy discouraging introductions of mountain goats may unduly limit choices for managing alpine ungulates, and may thereby impair the Division of Wildlife's ability to offer diverse and plentiful recreation to the people of Colorado. It may be possible to successfully manage introduced populations of mountain goats such that they do little or no harm to bighorn sheep. In light of the extraordinary value of alpine ungulates to outdoor recreation, we believe that policy options for managing mountain goats, including a resumption of transplants, should be carefully considered. We analyzed policy alternatives for managing sympatric populations of mountain goats and bighorn sheep. The objectives of our analyses included 1) predicting the probable risks to bighorn populations resulting from reinitiating transplants of mountain goats, 2) developing adaptive management actions that would control those risks, and 3) suggesting research and monitoring that would future management capabilities. Here, we report this analysis. APPROACH We examined the consequences of introducing mountain goats into habitats occupied by bighorn sheep. Although this is clearly not the only policy �106 option for managing sheep and goats (for example, transplants could occur where sheep are not currently found), we believe it is ultimately che choice that must be scrutinized. This is the case because any introduction of mountain goats into Colorado, regardless of its location, increases the likelihood that dispersing, introduced mountain goats will compete with resident, indigenous bighorn sheep. Moreover, such introductions also may limit future locations for bighorn sheep transplants if the question of competition remains unresolved. Thus, although transplanting mountain goats to bighorn sheep ranges represents an extreme management tactic, it also offers the strongest test of the viability of introducing more mountain goats to the state. RESULTS The results of our analyses were reported in a paper presented at the North American Wildlife and Natural Resources Conference. The paper is appended. Prepared by N. Thompson Hobbs Wildlife Researcher �107 BIOLOGICAL USING CRITERIA SIMULATION N. Thompson FOR INTRODUCTIONS MODELS TO PREDICT OF LARGE MAMMALS: IMPACTS OF COMPETITION Hobbs and Michael W. Miller Colorado Division of Wildlife, Wildlife Research Center. 317 W. Prospect Road. Fort Collins, CO 80526 James A. Bailey Department of Fisherv and Wildlife Biology. Colorado State University. Fort Collins CO 80523 Dale F. Reed and R. Bruce Gill Colorado Division of Wildlife, Wildlife Research Center, 317 W. Prospect Road. Fort Collins, CO 80526 INTRODUCTION The current abundance of many important species of wildlife America can be traced to successful reintroduction. Outstanding elaphus nelsoni), programs examples ring-necked of introduction species that collectively recreational to the citizens of this continent. is clear that benefits environmental costs. value gained by transplanting in prospect, In retrospect, the harm done. gone bad, for example European common carp (Cyprinus carpio), and cheatgrass (Bromus tectorum). Remembering carefully examine the potential communities the There are brome our obligation impacts before adding a species of plants and animals. whether starlings (Sturnus vulgaris), these failures underscores it their it is often uncertain animals will outweigh many examples of introductions and rainbow provide enormous offered by these species have exceeded However, elk (Ce.rvus (Phasianus colchicus), trout (Salmo gairdneri), opportunity and/or include Rocky Mountain pheasants in ~~orth to to existing �108 Hobbs Here, we consider introducing animals particular, we describe impacts plan ungulates that information into habitats from which on competitive to influence our approach to a variety models of those In and to Although general, of potential species, interactions. is substantially of birds absent. to examine among 2 on the problem they have been interactions the outcomes as an example, application can be focused the use of simulation of introductions actions provide ways et al. -- we use and should and mammals. PROBLEM DESCRIPTION There are many Introductions of survival may improve of pests species believe resources limiting 1986). 1982, of animal population that adding animal populations, introductions, such actions we must and design while growth those risk. 1979, Connor and Simberloff the likelihood desirable between interventions by fauna may upset of local influences species that are introduced. the tradeoffs Many (reviewed that competition may harm introducing with habitat species to an existing and increase management minimizing 1977, Huston or contribute However, at equilibrium of individual the probability diversity, or competition. exist species introductions foresee increase community To the extent with to an ecosystem. does not occur without populations disadvantage to wildlife, predation communities via competition. competitive benefits through a new species enhance 1983; but also Wiens among extinctions animals, animal It follows equilibria access to a new habitat ecologists Schoener to introduce human of endangered to reduction an animal reasons growth that suffer a In planning benefits and costs to capitalize of on their their costs. EXAMPLE APPLICATION We recently used simulation modeling to evaluate and costs of trans locating mountain goats (Oreamnos Colorado, and to formulate criteria for deciding the biological americanus) when such benefits within translocations �1 ' .•. v, Hobbs would be appropriate. broadly useful Policv Conte::t. We believe approach in planning It is not certain Colorado. as recently disappearance (Hibbard coincided 1980). successfully Over and Taber introduced (Rideout indigenous with native for limited have performed 1987, Risenhoover et al. 1988), that might further discouraging restrict introductions alpine poorly Division goats because they were it seemed wise (Ovis to avoid and abundance. ~ountain (~akelyn actions However, limit choices to successfully has it was widely of Colorado goats may unduly goats goats were of Wildlife habitat. in many areas goats 1977). elevation It may be possible Rocky 1972, when sheep their distribution of mountain 1948-1971, of mountain high and hence, of mountain ungulates. populations populations of mountain (Feltner 1975,Denney of mountain to tundra habitats that mountain of the Colorado areas of suitable sheep populations a into the southern are reports 1900's until policy they compete illustrates and that their certain and Hoffman translocations to mountain There it is fairly additional introduced ranged glaciation, 1967). from the early the last 15 years, canadensis) managing goats ever large scale loss of alpine Regardless, from Colorado believed goats were as late as 1897, but these are questionable Rutherford prevented mountain that mountain with application introductions. as the Wisconsin 1958, Hoffman in Colorado absent whether Some hypothesize Mountains our specific et al. -- policy for manage such that they do little or no harm sheep. Objectives We analyzed mountain goats resulting alternatives and mountain their populations included: policy sheep using in an alpine 1) predicting a model ecosystem. the probable from reinitiating for managing risks trans locations sympatric simulating The objectives to mountain of mountain populations the dynamics of of of our analyses sheep populations goats, 2) developing �110 Hobbs translocation research Model guidelines and monitoring habitats policy enhance the consequences occupied option by mountain for managing occur where choice goats likelihood into Colorado, indigenous future risks, 4 and 2) ~i~ggesting management to mountain sheep capabilities. populations and mountain Mountains. we assumed that modeled types, and meadows. we chose location to enhance from different any introduction increases compete of establishing "worst grasslands the generality geographic goats goat conditions. in the central there were of it also of mountain traversed to simulate also may new mountain case" interactions this area with mountain tactic, of the if the question management populations within it was the transplanting to simulate on alpine intensively. us to draw on data although to represent not the only such introductions transplants an extreme into alpine transplants we believed goats will Moreover, Thus, km2 were used than an actual goat of its location, sheep we wanted goat populations cliffs (for example, test of the viability was constructed this is clearly mountain sheep. represents in the state. The model introduced unresolved. the strongest goats This was the case because for mountain ranges mountain found), regardless mountain locations remains offers Although sheep are not currently competition sheep Rocky 40 km2, of which 2 distinct a hypothetical 20 habitat area rather of our model, and to allow locations. Description Our model cohorts was structured of 2 populations modified at a yearly conditions. computer senior future sheep and goats that dispersing. resident, Model those of introducing sheep. that had to be examined. mountain limit that would minimize -- Context we examined could that would et al. code Model (Fig. 1). matrix Vectors time step in response behavior implementing author). as a Leslie was governed for 2 sexes for survivorship to simulated by several these assumptions and 12 annual and natality were environmental key assumptions. can be obtained by writing (The to the �111 Hobbs The mode.l represented alpine and subalpine habitats populations ~sed different frequently on steep cliffs 1981; Chadwick data), mountain 1971; D. F. Reed, assumption goats assumed spatial 1983; D. F. Reed, Colo. Div. wildl., in density, were not strongly sheep were competition with we further dispersal. assumed to steep terrain a pivotal as their Moreover, It distribution of 1983:83). Thus, (Chadwick in Colorado. seen in northern we assumed to lower elevations that competition reduced the number between we ranges that mountain to avoid mortality offspring For both produced in juveniles 1986, Smith 1986). declining food availability responded to random, than are sheep. annual variation season, which forage rates and mountain sheep in sufficient in spring, and elevated (Nichols because 1980, mountain sheep goats have (Adams and that goats are less sensitive Vegetation growth stochastically. in and undernutrition in precipitation also varied growth species, than those of mountain et al. 1984), we assumed and mountain harvest, goats and adults However, goats Population mortality, mountain status. that are more catholic 1983, Dailey mountain to obtain high quality of surviving and wishart natural simulated their nutritional rates of over-winter between of both populations. by natality, their ability lowered of the growing (Geist into meadows from predators, separation growth regulated amounts food habits unpubl. slope However, goats disperse most 1980; Schoen Div. wildl., data). using goats. Interactions that impaired reside but that sheep will not use cliffs. and did not migrate sheep acts to depress the model were goats of lower of ecological operative sedentary Colo. 5 that sheep and goat 1977; Thompson grasslands unpubl. of pressure is not limited mechanisms mountain -- goat populations we assumed (McFetridge sheep use adjacent increase mountain Bailey terrain: and ridges that in the absence Jorgenson 2,700 m. of the model was that mountain populations appears sheep and mountain above alpine and Kirchoff while mountain et al. as well to in the model as to duration Stocking rates of �11:2 Hobbs mountain sheep individuals and goats on alpine by controlling In addition ranges the amount to nutritional directly of forage effects et al. -- influenced available on recruitment, 6 nutrition of per capita. simulated mountain \ sheep populations assumed were that infectious cause precipitous survival (Demarchi the population population and/or compromise May and Anderson probability above a density herds through infections increases with individuals in the model increased linearly pneumonia epizootics in Rocky 1984, Andryk and Irby 1986, Bailey lungworm lamb mortality (Protostrongylus in mountain infections as ewe density increased and Samson mountain juveniles sheep, (Geist 1984, Festa-Bianchet declined 1987, Robb goat populations unpubl. data). We assumed classes 1-5) reduced sheep 1986, (Stelfox 1974, 1987, Samson that dispersal their survivorship (Hudson and Stelfox 1987, Samson Festa-Bianchet to disease and by juvenile than are by dispersal and Stevens at each with et a1. 1987). tend to be regulated 1983; Houston spp.) associated 1987, Robb are far less subject but their numbers 1982; Stevens rates sheep populations lungworm Mountain mortality et al. 1980, Wishart Lamb mortality Festa-Bianchet 1987). with density Mountain et a1. 1979). 1984, 1979, 1988). that parasitic et al. 1987) and ewe condition and May 1983, Mollison for epidemic increased individuals 1982, May 1972, Feuerstein of increasing (Anderson et a1. 1974, Schmidt Samson the proportion naive (Woodard 1976, Festa-Bianchet pneumonia parameters Festa-Bianchet can cause high assumed and that lamb 1982, Dietz and Wishart We also assumed following of immunologically (Demarchi We spp. can occasionally We derived North America 1986, years diseases. epidemics, We further in protected during et al. 1980, Onderka 1986). recruitment of a die-off documented from pneumonia to pasteurellosis of immunity and parasitic by Pasteurella for several 1972, Bailey threshold. throughout Schwantje resulting 1979, Anderson Thus, from those caused reduced susceptible density by infectious disease die-offs is drastically outbreaks regulated of 1988; J. A. Bailey, mountain time step. goats (age (We do not imply �113 Hobbs that all dispersing goats die, but the model mortality in ~he same way.) for males (Ste·v·ens1983), Harvest was used Achieved harvests between population determined function objective. objective Accuracy and precision by the level of resources in greater accuracy Our model was written execution Modeling on IBM compatible Environment model construction species invested than in the model. The difference population size harvested rate, which of population a~d of coho r t numbers. of animals success 7 for fe~ales objectives. of current The number and hunter 33% lower of both by population and estimates for dispersa: fraction populations influenced objectives of harvest controlled resulted were rates were and were a constant to regulate the harvest stochastically. Dispersal accounts et al. -- varied estimates in census. was a were Higher investment and precision. in FORTRAN 77 (Microsoft microcomputers. (Quaternary We used Software, version 4.01) the TIMEO Fort Collins, for Integrated CO) to facilitate and analyses. Model Analvses We used mountain the model to examine goats and mountain 1) What populations mechanisms 3) are most Do characteristics of mountain important the outcome Can harvest increase the likelihood To address sheep, of alpine habitats goats and mountain goat populations (e.g., of the other, and in absence of any management (i.e., food, disease, dispersal, primary interactions? between sheep? simulated we presumed on impacts? topography, of coexistence 1, we examined simulations, those of competitive question these initial of and what ecological in controlling influence in populations 3 questions: mountain production) mountain the absence of regulation sheep and to answer is the impact of introduced established 2) mechanisms dynamics all regulating parasitism) of each species interventions. factors were operative. except in In harvest �114 Hobbs We then structured mountain sheep and mountain and mountain goats of the simulation behavior simulation assumed added sheep populations, To address question of competition. habitat contained primary production. question trajectories parasitism) "conservative" minimal in census (> 1/2 curl), and either-sex included and ewe mountain RESULTS populations all any difference regulators of mountain in census, harvest of We first We of mountain variables levels on the the percentage of annual of harvest of net on (food, competition, two harvest a males-only in outcomes. the influence The conservative and either-sex species. runs, we altered We also examined activity, goats. of habitat and altered all natural investment portrayed of mountain simulated distinct patterns sheep and mountain mountain sheep populations The series of random for years 51-100. 1 used sheep, effects model harvest at year a the 2 halves as regulators in model both approach harvest goats. specified regimes, included a for mountain sheep The aggressive harvests of mountain of both ram goats. AND DISCUSSION The model goats, heavy of both and disease and meadows activated. Thus, of mountain growth differences and "aggressive." investment strategy regulated 3, we examined with between we reinitialized 51. to effects In separate introduced in the first and second half 2, we examined in cliffs To address of year of parasitism and examined outcome population alone that included comparison vs. 51-100 years), sheep populations effects sheep were To facilitate runs could be attributed subsequently simulations Mountain at the beginning that food supply disease, 50. (0-50 years of mountain of lOa-year goats. at year processes1 stochastic a series 8 et al. -- numbers used of growth goats. In the absence displayed for years in naturally-regulated episodes 1-50 was of mountain of exponential identical to that �UJ Hobbs increase follo~ed sequentially slow recovery (fig. 2A). approximately 20-year 3 females/km2. about mountain sheep Feuerstein absence These Similar throughout of mountain patterns introduced (Caughley goats was about 4.6 females/km2. (r = 0.13, simulated goats resemble those calculated When population depended included of mountain sheep, we formulated the two species mountain 1975, Stevens in simulations mechanisms shifted reached downward Density-dependent growth by reducing and Driver a stable effects natality of mountain 1986). sheep gr owcb . population 2C). (Fig. following on food supply and increasing et al. an established of mountai~ equilibrium goats Fig. 2A). and Wishart regulated sheep for mountain after their population alone in mountain of ungulates 1978, Youds representing regulated In the displayed populations performance of (r) for mountain 1980, Jorgensen so that food supply eventually point goats. population on which the model for growing the resulting data). (r = 0.11, sheep of 1976; density the first 10 years (Haas and Decker goats were strongly equilibrium sheep unpubl. (Fig. 2B) typical those for mountain (Hibbs et al. 1969, Vaughan 1980) and mountain and Stelfox rates of increase at in populations Equilibrium and peak densities goat populations 1970). During instantaneous Fig. 2B) exceeded These values observed (Hudson mountain by equilibrium into new habitat introduction, have been 9 s~asls, repeated attaining 1989; Colo. Div. Wildl., simulated followed temporary sequences with populations the Rocky Mountains sheep, growth decline, disease-induced intervals, et al. 1980; Hass exponential by precipitous et a l.. -- growth, That introduction acted winter When of to regulate mortality in both populations. When mountain effects were of food supply, added stable sheep populations to the simulation, or increasing Fig. 2D). performance parasitism, Thus, following of goats of sheep populations initially and epidemic the mountain for 27 years introduction were regulated disease, and mountain sheep population appeared goat introduction initially by increasing appeared stability by the combined (years to improve goats to be 50-77, the in their numbers. �116 Hobbs However, during epidemic. patterns during years in mountain epidemic disease. prevented occurred 50-77. increase importance the original mountain these conditions from that values sheep mountain onset competitive appeared net primary only slightly sheep numbers the rate of goats ultimately vigorously following emphasizes interactions the between these effects. to have 8 females/km2, in mountain of density-dependent from recovering little impact production (1,700 kgfha) , equilibrium responded natality rate retarded with mountain of time lagged When we increased reduced (Fig. 2D vs. Fig 2C) results in influencing from 4.5 to almost regulates densities by 1,000 kg/ha of mountain but population (Fig. 3A). on the outcome at levels well below goats trajectories This suggests over of that disease the food-based carrying of the environment. In contrast, and meadows changing substantially introduction of goats, sheep populations than changes area. populations because did not respond These patterns To the extent of habitat mountain to changes on probability can expand characteristics influenced responded and hence, the proportion and had moderate in production goat populations rates. did not recover in growth and delayed competition and the importance of competition. competition sheep population Comparing Environmental increased because This reduction However, of disease two species habitat ~y a disease was interrupted sheep population sheep density the mountain the die-off. density, mountain stability 10 (Fig. 2D). These capacity 77, this apparent The simulated die-off sheep year et al. -- thereafter in habitat of the effects depend translocation sites (Fig 3B). Simulated in initial penalty that these assumptions before Mountain extent of area on population on our assumption without by cliffs area to a greater outbreaks. to these changes into meadows of alpine sheep performance effects of disease contributed conditions that mountain in their are correct, in Colorado mountain for goat reproductive then landscape will have little or �1.L, -I Hobbs no impact on the eventual considerations outcome in selecting sites When we added hunting equilibrium propelled between failed allowed mountain to the model, investment to eliminate goats disease sexes of goats were harvested mountain goats can be potent management coexistence of these species (Fig. 3C) because their densities Based potent mountain below migratory release a threshold ability to thrive in meadow interactions populations of mountain habitats will depend after is a commitment investment in inventory It is clear controlling processes population goats extent to direct goat numbers occur over time scales numbers goats on demography difficult of mountain of to allow sustainable densities by maintaining goats can be depress non- mountain goat of the demonstrated and their apparent Preventing ability competitive for managing sites before they occur. goat trans locations regime of We within for both species and that regime. that a "wait and see" approach involves substantial that make changes to compare appears Characteristics on criteria harvest and in the absence in planning sheep. for mountain harvest outbreaks. ranges. than on choosing to an aggressive needed regime is the case because used by mountain criterion sheep that mountain 1983), strategy that although stabilized criteria long-term even when both and can significantly (Stevens to a greater sheep, for disease on alpine from our simulations mountain were unimportant introductions the fundamental Colorado critical This to achieve harvest at maximum we concluded to those ranges. with harvest ranges tr~,slocations. sheep populations, with mountain sheep, sheep Thus, we surmise sheep populations sheep populations dispersal surmise on alpine sites may be relatively translocations in competition 11 impcr:dGt Conservative in mountain an appropriate with mountain mountain (Fig. 3D). cycles competitors on these simulations, competitors an aggressive moderately. (Fig. 2D), applying mountain it was possible in census to prevail but remain for potential sheep and goats using by liberal regimes of competition et al. -- among peril. in mountain locations. sheep populations to Cyclic disease sheep Effects of mountain may be impossible to detect, �Hobbs particularly if sheep herds to "control" herds declining phase misleading. elsewhere. if those observations years!). sheep Such cycles The outcomes mountain sheep assumptions future contribute needed present. regardless on animal offer about (e.g., the future even 27 of mountain on our assumptions and responses. to any policy to hinge sympatric on preventing mountain between as well unresolved and motivate in managing recurrent disease goat populations density to disease, important Success of These recommendations, that uncertainty. that relationships distribution, goats have no effect long time periods security or to be sheep may be dangerous, rely heavily and their susceptibility to be in a static are likely that inferring performances appears are compared understood. scenarios of whether We suggest populations poorly to reduce happen in mountain spurious uncertainty sheep populations epidemics, suggests and goat population research mountain remain of these "controls" over relatively offer goat introductions such comparisons no change occur inferences if disease cycle, the model on observing receiving If those in the disease Moreover, on sheep based in areas 12 et al. are of mountain sheep as effects questions of harvest in mountain sheep management. Both efficacy of population strategies for regulating experiments incorporated experiments should achieving require managers, biologists, treatments. comprehensive ecosystems. design, ability plans of both census reliable conclusions, combined with such endeavors to manage disease sheep. and removal herd long-term commitment to apply and evaluate for a diversity and These methods responses such management are essential outbreaks in controlled for mountain and should monitor and researchers We believe for preventing should be evaluated into management objectives, To provide careful densities test effectiveness population management. control to experiments and cooperation will of management to enhancing of ungulate for our species in alpine �L9 Hobbs et al. -- 13 CONCLUSIONS Our example planning application introductions. initiating Models translocations. characteristics illustrates can be used Although of the habitat where management after mountain depend goats and mountain on the ability Models populations impacts of one species introductions. longer Models focus on it is clear to execute For example, specific co-existence in Colorado of will probably in future performance that relatively must be considered that brief, on effects in tor are planned, "surprises" illustrated suggests models them. local extinction for decisions species. long-term in criteria of mountain sheep empirical studies of introductions may be the only feasible of for that occurred .may offer a on competition way to make infcLences over time scales. Planning program introductions designed fundamentally substantial should in identifying difficulty experimental (Walters those criteria responses and Collie are met. as well Models as a can be in the target population, Our model comparisons underscores for success, demonstrated among populations the need when the they cycle for sophisticat2~ 1988, Walters et al. 1988) if those are to be reliable. A common that the best response to modeling efforts available information is simply is to say, we don't understand with habitats No doubt, criteria performance. in making This difficulty designs involve whether those of population out of phase. comparisons to evaluate useful particularly That on another of sympatry foundation between Our model usually ranges harvest in revealing The predicted after 27 years weak sheep on alpine are also useful criteria on the wherewithal are introduced. to effectively of interest. to evaluate trans locations should be contingent species uses of simulatinn such criteria that introductions actions several well enough to model like the one we have outlined wildlife not up to the task at hand. populations their behavior there are times when we should heed is or their interactions at any level of resolution. such doubts. To the extent that �120 Hobbs it is better appropriate However, to be ignorant ;"'hendata are scarce it can also be argued the potential risks than mislead, benefits involved. offered a modeling and processes that when approach are poorly a species prudence may demand of simulation modeling lies in forcing may ~ot be is that poor, cannot In such cases, 14- -- unde rs t oo d . our understanding by introducing et al. offset then the that we leave well enough alone. The utility recognize Bleloch the " ...consequences 1986:3). us communicate of what we believe This process why we made can improve us to explicitly to be true." the quality (Starfield of our choices and and help them. ACKNOWLEDGMENTS D. J. we thank M. Festa-Bianchet, Samuel, K. G. Smith, W. D. Snyder, reviewing helpful an early version comments editorial wildlife REFERENCES Adams, Freddy, assistance. Restoration central and for of this manuscript. N. McEwen by Colorado offeed p,o'lided Federal Ai.d to w-1S3-R-2. J. A. Bailey. J. Colorado. R. M. disease 1982. agents. Population wildl. Pages winter Manage. forages and control in R. M. Anderson of infectious of mountain goats diseases. of infectious and R. M. May, Dahlem eds. Konferenzen. Berlin. Part I. Nature 1979. in 47: 1237-1243. dynamics 149-176 R. M., and R. M. May. diseases: 1983. Transmission biology Springer-Verlag, Anderson, W. D. wishart W. M. R. C. 'Kufeld and C. E. Braun Our work was supported Project and T. M. Pojar, CITED L. G., Anderson, H. Olterman, D. A. welch, of our model. in their reviews J. Population 280:361-367. biology of infectious �, ), rz; Hobbs T. A., Andryk, and L. R. Irby. 1986. use by rncun t a i.n sheep prior Northe~n J. Bailey, sheep: Caughley, 1986. The increase biology, management Sheep and Goat Counc. G. 1970. Himalayan Chadwick, D. H. 1983. CA. Dailey, T. V., N. T. Hobbs, Denney, Proc. Dietz, K. 1972. Northern R. N. populations Ecology 1986. Canyon bighorn Symp. Northern with emphasis on 51:53-71. Sierra Club, San Competition, scientific method, and Am. Sci. 74:155-162. and T. N. Woodard. 1984. by mountain 1977. goats Experimental and mountain sheep in disease May, Population Konferenzen. G. 1972. Goat Symp. population agents. biology and Parks Division. sheep. goats in Colorado. 87-102 in the transmission dynamics in R. M. Anderson and R. M. diseases. Dahlem Game, of the Colorado Fish and Parks Div. Game, Denver, Fish CO. 64pp. Festa-Bianchet, ewes. M. 1987. Ph.D. Thesis, Individual Univ. of Berlin. A 75 year history Colorado bighorn 1:29-36. of infectious Springer-Verlag, A look back: of mountain patterns Pages of East Kootenay 2:22-28. and management Mountain Overall eds. recovery Wild Sheep Counc. Status Internatl. 1982. Post die-off infectious Feltner, S:;ir.p. J. Wildl. Manage. 48: 799-806. R. A. Trans. Bienn. Bienn. the color of winter. of diet selection Colorado. Demarchi, and habitat 208 pp. in ecology. comparisons 15 5:325-340. E. F., and D. Simberloff. null models of Waterton and dismanagement. of ungulate A beast die-off. -- 5:272-289. and die-off thar in New Zealand. Francisco, Connor, Eruption characteristi~s to a pneumonia Wild Sheep and Goat Counc. A. Wild Population et al. reproductive Calgary, Alberta. success 229 pp. of bighorn sheep �122 Hobbs Festa-Bianchet. M. comments Goat 1988. on preventive Counc. Festa-Bianchet, Northern Wild V. Geist, Sheep V. Mountain Press, 1982. goats. sheep herd. Chicago, Hibbard, C.W. Hibbs, Mich. R.S., Acad. reference Wild Hudson, predation, special Univ. Symp. Northern Wild 1988. Pleistocene 1969. Counc. bighorn 2: 143-167. and mammalian local The mountain Conf. and history dynamics 2: 100-112. faunas. Arctic tundra pp. 143- and alpine in mountain goats: 66: 228-238. Populations a system 34: 409-418. IN. limitation Can. J. Zool. goat in of holarctic (eds.). Bloomington, Resource 1976. Sheep Counc. introduced to their vertebrate Press. Rockies: and Proc. 43:3-32. Origin cropping. sheep 67: 699-705. reference R. J., and J. G. Stelfox. of the Canadian Univ. 3: 23-24. inbreeding, and Nat. Resour. 1967. D. B., and V. Stevens. sheep area, to mountain Sheep and Goat and D. L. Gilbert. N. Am. Wildl. a test by experimental 1980. and evolution. A study of a recently Sci. Arts Lett. Inidana SYTIp. Spec. Rep. 48. 19 pp. 170. In H.E. Wright, Jr., and W.H. Osburn environments. Bienn. Triangle and Goat Counc. of North American and R.D. Taber. with River-Almont Wild Sheep Can. J. Zool. Summary Trans. ecosystems, Houston, and to and W. H. Rutherford. with lamb mortality: L. D., F. A. Glover, Hoffmann, W'il.dSheep in relation sheep. in behavior control" Symp. Northern effects. Colorado. ·.d.th 11. 383 pp. 1980. Bighorn 1958. faunas. Northern bighorn Div. Wildl., a study Symp. Northern Bienn. 1989. population Colo. On "population Bienn. C. C. sheep, 4: 364-371. in the Taylor sheep: Haas, W. J., and E. Decker. Hass, Symp. Lamb survival C. P. Hibler, a case study. 1971. 1984. and Goat Counc. sheep mortality Chicago in bighorn Bienn. load in Rocky Mountain V., R. L. Schmidt, 1978-1979: Geist, management. M., and J. Samson. lungworm Bighorn epizootic 16 6:66-76. maternal Feuerstein, A pneumonia et a l . -- and diseases approach. of bighorn Proc. Bienn. �123 Hobbs Huston, M. 1979. A general hypothesis of species e tal. diversity. -- 17 Am. ~at. 113: 81-101. J. Jorgenson, T., and W. D. Wishart. population Bienn. May, R. M. responses of an expanding Symp. Northern 1983. 1986. Wild Parasitic Preliminary bighorn sheep herd Sheep and Goat Counc. infections observations as regulators on in Alberta. 5:348-365. of animal populations. Am. Sci. 71:36-45. May, R. M, and R. M. Anderson. diseases: McFetridge, Mollison, Part II. Nature 1977. Strategy R. J. groups. D. Proc. 1987. Soc. London Nichols, L. Onderka, of resource Risenhoover, use by mountain Mountain Goat Population dynamics of mammalian Aerial census Symp. goat nursery 1:169-173. and classification Symp. Northern in southern Wild Sheep 1984. Alberta. diseases. Symp. Zool. of mountain goats in and Goat Counc. A major Bienn. bighorn 2: 523-589. sheep Syrnp. Northern Wild die-off Sheep from and 4:356-363. C. B., and R. S. Hoffmann. Species of infectious 280:455-471. D. K., and W. D. Wishart. Goat Coune. Rideout, biology Internat1. Bienn. pneumonia Population 58:329-342. 1980. Alaska. 1979. 1975. Oreamnos americanus. Mammal. 63. 6pp. K. L., J. A. Bailey, Rocky Mountain bighorn and L. A. Wake1yn. sheep management 1988. problem. Addressing Wi1d1. the Soc. Bull. 16:346-352. Robb, L. A. 1987. Gastropod Protostrongy1idae) transmission. Rutherford, Samson, W.H. on a bighorn M.S. Thesis, 1980. with 1ungworms. Univ. Alberta, J. T. Jorgenson, infections hosts range: of 111 pp. 29(6):32-35. and W. D. Wishart. rocky mountain Dis. 23:396-403. (Nematoda: aspects Edmonton. Colo. Outdoors of free-ranging J. Wildl. of lungworm sheep winter Sheep or goats? J., J. C. Holmes, Experimental intermediate 1987. bighorn sheep �124 et al. Hobbs Schmidt, R. L., C. P. Hibler, evaluation Manage. J. Schoen, of drug treatment and W. H. Rutherford. of lungworm in bighorn 18 1979. An sheep .. ;. wildl. 43:461-467. W., and M. D. Kirchoff. southeast Alaska. and w-2l-l, Schoener, T. R. Spraker, -- 2. T. W. Alaska 1981. Habitat use by mountain Dep. Fish and Game. goats in P-R Proj. Rep. w-17-l0 67 pp. 1982. The controversy over interspecific competition. Am. on interspecific competition. Am. Sci. 70:586-594. Schoener, T. w. Nat. 1983. 122:240-285. Schwantje, H. M. 1986. southeastern Goat Smith, Starfield, study of bighorn Columbia. Bienn. Rates Alaska. and causes and wildlife G. J. wildl. Manage. management. 1974. regulation Symp. Northern of mortality A. M., and A. L. B1eloch. J. sheep herds wild in Sheep and 5:231-252. 1986. southeast A comparative British Counc. C. A. Stelfox, Field experiments Range theories. Building Macmillian. Proc. models New York, of bighorn Bienn. goats in 50: 743-746 1986. ecology in mountain sheep for co,1servation NY. 253 pp. in relation Symp. Northern wild to self- Sheep Counc. 1: 67-76. Stevens, V. 1983. population. Stevens, The dynamics Ph.D. Thesis, V., and C. Driver. goat herd Thompson, R. W. impacts 1980. Goat Counc. in an introduced washington, Initial Mountains. Seattle. observations Bienn. mountain goat 201 pp. on a tagged mountain Symp. Northern wild Sheep 1:165-174. Population and trapping Nest wilderness Univ. 1978. in the Olympic and Goat Counc. of dispersal Area, dynamics, of introduced Colorado. 2: 459-464. habitat utilization, Rocky Mountain Bienn. goats Symp. Northern recreational in the Eagles wild Sheep and �)1_J Hobbs Vaughan, M. R., 1975. Oregon. Wake1yn, M. S. Thesis, L. A. 1987. Colorado. Walters, Oregon Changing J. Wi1d1. to fisheries Fish. Aquat. J. A. Wa11ow~ Ll.? Corvallis. conditions on bighorn -- 19 ~ountains, pp . sheep range~ in 51:904-912. 1988. management? transient goat ecology, State Univ., habitat Manage. C. J., J. S. Collie, estimating Wiens, of mountain C. J., and J. S. Collie. useful Walters, Aspects et al. Is research Can J. Fish. Aquat. and T. Webb. responses on environmental 1988. Sci. 45:1848-1854. Experimental to management factors designs disturbances. for Can. J. Sci. 45:530-538. 1977. On competition and variable environments. Am. Sci. 65:590-597. Wishart, W. D., J. Jorgenson, bighorns from pneumonia Sheep and Goat Counc. Woodard, in southern Wildl. survival, Manage. Northern and W.H. Rutherford. and mortality W. K. Hall, data on mountain Wild Alberta. A minor die-off of Bienn. Symp. Northern 1974. Bighorn lamb in south-central Colorado. and R. A. Demarchi. 1980. J. 38(4):771-774. J. A., D. M. Hebert, Preliminary 1980. 2: 229-247. T.N., R.J. Gutierrez, production, Youds, and M. Hinton. goat population Sheep and Goat Counc. growth. 2: 482-519. Bienn. Symp. Wild �126 Hobbs FIGURE CAPTIONS Figure 1. deaths of mountain Age-structured disease, to the upper In both species, the number is controlled 2. alpine habitats sheep epidemic disease, mountain sheep (dashed dispersal mountain sheep regulated (dashed Effects of mountain sheep, assuming and 2,700 kg/ha). lines) epidemic and habitat sheep populations disease, are limited and parasitism. by food supply of mountain and of of mountain by food supply, are regulated habitats. performance by lines) Mountain A- of mountain in alpine and dispersal. of on simulated into alpine (dashed goats C - Effect performance management production of D - Effect are limited on population into by food supply goat populations introduced of net primary Mountain growth of mountain by food supply. Mountain introduction introduced performance goats are regulated populations two levels of mortality for food supply, growth sheep populations disease. of population goat of animals is controlled for food and dispersal. are regulated Mountain of ungulate Effect (solid B - Population (solid line) on population and dispersal. food supply, competition mountain line). by flow by epidemic A - Population line), where food supply trajectories populations (solid line) on population introduction and of winter adds to effects introduction sheep goats is controlled of management. competition and epidemic 3. sheep by intraspecific parasitism, Figure dispersal of ungulate and parasitism. and mountain goat availability in mountain 20 and harvest. trajectories by intraspecific goat Mortality in mountain in the absence mountain by per capita and harvest; starvation, Simulated regulated green-up. Mortality parasitism, one. -- births is indicated dispersal, Figure representing Natality food and date of spring on goat numbers. model goats. to the population by starvation, dynamics sheep and mountain from the lower box added population et al. habitats are limited goat populations B - Effect of (1,700 by �127 Hobbs mountain goat assuming different Numbers introduction by arr0"S that is contributed limited Effect arrangements (solid by meadows. of mountain of mountain sheep to "aggressive" epidemic lines) (thick z:1e0p, in alpine h ab i t.a t s , of the total area (cliffs sheep populations disease, and parasitism. are limited lines), and meadows by food supply (solid lines) assuming lines) and "conservative" Mountain lines) are goat and dispersal. c- performance are harvested (thin lines) 21 + meadows) (dashed on population populations -- of mountain Mountain goat introduction (dashed performance of cliffs give the proportion by food supply, populations on population et al. harvest according regimes. �H ,, ,, en .••. .----t Q) ;:I 'H Ii:.. ,- .... .. ,,, , , , , , ,, \ \ I N AT \ AGE = 1 I I I I , / I / / I " .. '" " ~ __ J"',_, ; ••••••• •• •• \ \ \ .. .. \ \ N AT - ;,, , ,., I ,. I , I HARVEST 00 N .-j , AGE == 2-12 \ .. , \ ,, �'"_-< rol 300 ----------------------- 7.5 N ------r - ~oo .-------- s. '" I (1) H ;:::l 1>0 'r-l rJc, - 6.0 A 6.0 B 200 (/) 200 ~ 4.5 W 4.5 (/) _J « :E , , , 100 W , LL 1 I I / --- \ '" / / ~ / / o ___ -'- __ J. - . I I 3.0 100 ,, ---- 1.5 30 0.0 o --10 0 50 40 0.0 =t:t: 50 40 30 20 W - >- N (/) 300 -------------------------- 7.5 0 « _J 200 /, .- f \ r- ••.• - "\ - •.•. , \ '\ f , 100 ,, - - ,, f / . 3.0 '- , a.. . - , /1 1.5 I . '" 1 100 - , I ,' I I \ - I I I 1 o L... _____ 0 L _____ 20 '_'-- 40 __ 0.0 100 _J 60 <:-r 4.5 ,, ~ I r n, D 200 ' ... / ::> o 6.0 C 80 YEARS AFTER o t- ~j7.S 300 Z I- « ~ W LL /- _J.__ __ W ...J 1.5 / ___t__ ___ ____ I , '" 1 / 20 10 0 / , ,' 3.0 , E sc - L ______ 0 20 I I \ ,, ,. ,' - " INTRODUCTION 6.0 0 4.5 Z 3.0 t- ' 1 I 1.5 ---,_- 0.0 60 80 0 -c ...J I 1 / 40 -, ffi 100 ::> a.. 0 a.. �130 3 Figure 400 ~--------------------------------~ 10.0 A 8.0 300 2700 6.0 200 1700 \ ~; , 100 ~ C/) W ..J < :E ,,4' I 0 L_ __ 0 4.0 1\, , -, 1.:- ••;", « " c \... , I ,,\.... ,,'/ 20 40 60 ~ - 0.6\ .r, ..'.. /' 200 N 0.3\':': I- -c ..J ::::l oa.. a.. 80 0.0 100 7.5 X /' u, 4.5 - 3.0 , 20 1.5 ---_- \-:.. -;. -:.. '- 60 80 0.0 100 . 7 5 300 ,..---------------------, C 6.0 CONSERV A TIVE 200 I 4.5 3.0 100 1.5 o AGRESSSIVE L- o -L 20 YEARS L-~ 40 AFTER __ ~ 60 ~ 80 !:: (/) .' ..J o ~----~------~~~~------~~~-o ~ >- " 40 -c 6.0 I -:. ~ C/) W ..J W B . E ~ I"\:' . ~ _;:"1 .~., / -, ".' i .. . , .... '/r ... , I, <, .7 '\ / , '\ , •• , .,' e ..... _,.".-, / / -~ .•-.; ,. -.". ,, 100 Z o- \ 0.3, 0.6, 0.9 0.9 W C/) 2.0 300 ,..-------------------, u, - CII I -I ___:;:~:::::::::=:J .Ls..:» __ W - _,- ,,_<. _J' ,/" ~~~ t____-=-=----1 _ /'- ~ 0.0 100 INTRODUCTION z w c z o l- -e ..J ::::l o, o a.. �l.3;' Colorado Division of Wildlife Wildlife Research Report July 1990 JOB PROGRESS REPORT State of Colorado Project No. ~W_-=1~5~3_-~R~-~3 Work Plan No. Job No. Period Covered: Author: _ Mammals Research 2A Mountain Sheep Investigations 7 Experimental Evaluation of Mountain Sheep Transplanting Disease Treatment and July 1, 1989 - June 30, 1990 M. W. Miller Personnel: N. T. Hobbs, R. B. Gill, J. H. Olterman, D. A. Reed E. E. Ryland, and ABSTRACT A prospectus was prepared outlining a management experiment to examine the effects of ewe harvest on movements and distribution of bighorn populations. Thirty-four Rocky Mountain bighorn sheep (19 ewes,S rams, 10 lambs) were captured from 2 sites in British Columbia, Canada, and transported to the Forbes Trinchera Ranch in southcentral Colorado to establish an experimental management herd. Translocated bighorns appeared healthy, although some individuals were infected with Pasteurella spp. and/or Protostrongylus spp.; no serologic evidence of exposure to respiratory viruses was detected. Movements of translocated sheep were largely confined to the vicinity of the release site for the first 2.5-3 mo after release; however, by late July individuals from the transplant herd had contacted bighorns from at least 3 other herds. Preliminary observat:i,.onssuggest potential for disease transmission'by translocated bighorns, as well as effects of dispersal on establishment of transplant h¢rds, warrant further investigation'through experimental management. ��133 EXPERIMENTAL EVALUATION OF MOUNTAIN SHEEP TRANSPLANTING AND DISEASE TREATMENT Michael W. Miller P. N. OBJECTIVES Design, conduct, and report on management experiments to evaluate efficacy transplanting and disease treatment practices for managing mountain sheep populations. AGREEMENT 1. Design management 2. Submit research proposals 3. Begin implementing of OBJECTIVES level experiments. for funding. funded research. Colorado's mountain sheep management program is among the most aggressive in North America. Although some combination of management practices appears to have produced a threefold increase in bighorn numbers statewide over the last 20 years, the contributions of individual management strategies to this overall success cannot be discerned (Bailey 1990). Transplanting bighorns to unoccupied ranges and treating resident herds to control parasites are 2 of the most intensive (and costly) practices used to manage sheep in Colorado, yet neither of these programs has ever been evaluated experimentally to assess long-term efficacy. Recent analyses of available herd data suggested that only about half of all transplant efforts succeed in establishing viable bighorn herds, and that parasite treatment does not necessarily prevent disease outbreaks or improve performance of treated bighorn herds (Bailey 1990). Unfortunately, management practices for most of Colorado's bighorn populations are so confounded that even interpretation of the aforementioned evaluation is equivocal. Clearly, management-level experiments are needed to evaluate and compare efficacy and efficiency of bighorn management practices in Colorado. The Colorado Division of Wildlife's Terrestrial Wildlife Research Section is committed to conducting management experiments to evaluate efficacy of transplanting and disease treatment practices for managing mountain sheep populations. Agency-wide, however, using this approach for managing sheep (or any other species) has met with mixed reception. Until a broad base of support for experimental management is established within CDOW, the ability to conduct population-level research will be severely limited. The following are highlights of our initial attempt to establish bighorn herds for use in management experiments: Research Prospectus: Effects of Ewe Harvest on Movements and Distribution of Bighorn Populations - M. W. Miller, N. T. Hobbs, R. B. Gill, J. H. Olterman, and E. E. Ryland We have been working to identify priorities for research on bighorn sheep during the coming decade. As part of that effort, we recently built a �134 computer model depicting the current state of knowledge about bighorn sheep population dynamics. The model serves 2 functions: first, it allows us to examine the outcomes of different management strategies assuming our knowledge of sheep populatior iynamics is correct; second, it highlights whece knowledge is inadequate. One of the central assumptions of the model is that sheep populations tend to increase until high levels of mortality cause sudden and dramatic declines in their numbers. These population "crashes" are caused by epidemic disease. In our model, we assume that population density controls the probability of disease outbreaks, and thus controls the cycles in bighorn abundance. Published accounts of real bighorn sheep population histories as well as management experience strongly support this assumption. When we incorporate this disease-density relationship into modeling exercises, our model realistically mimics the dynamics of many Colorado bighorn populations. Without this relationship, model output fails to resemble what we think we see in the real world. Our modeling efforts suggest 2 conclusions that are centrally important to future management of bighorn populations. First, if we wish to prevent cyclic episodes of peaks and crashes in bighorn numbers we must regulate densities below threshold levels through harvests and/or transplant removals. It is also clear that harvests or transplant removals comprised entirely of mature rams will not prevent episodic disease outbreaks. Removing ewes must be part of the management solution. Transplanting offers only a short-term means of regulating density below threshold levels because all potential transplant sites in Colorado will be occupied in the foreseeable future. Moreover, inaccessibility and/or conflicting land use policies preclude trapping and transplanting as an option for managing some bighorn herds. Thus, ewe harvest will almost certainly emerge as an increasingly important tool for bighorn management in the next decade. The second important outcome of the modeling exercise focuses on the relationship between hunting and animal movements. Our simulations suggested that the efficacy of harvest as means of preventing epidemic disease requires that animal numbers be reduced without reducing animal home ranges. That is, if ewe hunting acts to restrict the area used by bighorn populations, then it may worsen rather than solve the disease problem. Our modeling results motivate a specific research project, which we outline here. The effects of hunting on patterns of habitat use and dispersion by bighorn sheep are poorly understood. It may be that activities of hunters act to limit patterns of range use by bighorn populations by concentrating them in areas of escape cover. Whether this concentration occurs, and how long it may persist, remain unknown. It is also possible, however, that harvest may enhance distribution of bighorns by encouraging animals, particularly juveniles, to use unfamiliar terrain. We propose to answer these questions to enhance our future ability to manage density in bighorn populations. To do so, we wish to participate in a cooperative program to reintroduce bighorns to the Forbes Trinchera Ranch. Such participation will provide us with an unequalled experimental opportunity to resolve the uncertainties we outlined above. We propose that Rocky Mountain bighorns from British Columbia be introduced to the Forbes Trinchera Ranch to provide 2 independent herds, established under similar conditions, from similar stock, in similar, but spatially distinct habitats. Once both herds are well-established (in 3-5 years), we will conduct an experiment to investigate the effects of ewe harvest on their distribution and movements. Specifically, we will test the hypothesis that �, ~- 1..)) hunting ewes will reduce density of bighorn populations dispersal. by enhancing Our experiment would use a design know as "before and after controlled intervention" (BACI) to determine sheep responses to harvest activities. In essence, this design involves observing the responses of both populations before and after imposing a limited ewe season on 1 of the 2 populations. Thus, the "un t rea t ed" population (exposed to limited ram-only ha rve s t ) serves as a control for any serial effects of time that may occur during the study. Operationally, we foresee using radio telemetry to observe patterns of habitat use by bighorns in the 2 Forbes Trinchera herds. We would monitor distribution and movements of adult ewes in both herds for 2-3 years under a limited ram-only harvest system. We would then monitor ewe responses after imposing a ewe hunting season on 1 of those herds during each of 3 subsequent years. A detailed agreement on season lengths and dates, permit numbers, a process for permit distribution, and other particulars will be reached through negotiations among Terrestrial Wildlife Resources, the Southwest Region, and Forbes Trinchera Ranch during a planning phase and approved by the Wildlife Commission before initiating this study. This project represents a unique chance to learn about the consequences of management activities and provide added recreational opportunities for Colorado's bighorn hunters without impacting established bighorn herds and their management programs. Our study will also complement other existing and planned bighorn research and management activities. Moreover, its results should aid in guiding decisions on alternatives for future bighorn sheep management in Colorado. Forbes Trinchera Bighorn Translocation MATERIALS AND METHODS Rocky Mountain bighorn sheep were translocated from British Columbia to Colorado in order to establish 1 (or more) bighorn herd(s) for experimental management purposes. Bighorns from Columbia Lake and Stoddard Creek, British Columbia, Canada, were captured using a corral trap or drop net on 16-18 March 1990. We collected blood from and examined each animal included for translocation, and injected each with ivermectin and long-acting oxytetracycline (LA 200); we also collected pharyngeal swabs from 15 ewes. Feces from adults and lambs were pooled and examined for Protostrongylus spp. larvae. Modified horse trailers were used to transport a total of 34 bighorns to the Forbes Trinchera Ranch near Ft. Garland, Colorado. On 18 and 20 March 1990, 2 groups of bighorns were released on the ranch in the North Fork of Trinchera Creek vicinity; altogether, 19 ewes,S rams, and 10 lambs were introduced (Table 1) at the same location. All sheep were marked with blue eartags (numbered 1-28 and 41-46). In addition, we fitted 17 adults (12 ewes,S rams) with radio transmitters (frequency range 172-173), and marked the remaining adult ewes with blue visual collars (numbered 1-4 and 9-11). Forbes Trinchera Ranch personnel have monitored sheep movements from the ground weekly, and all radioco1lared sheep have been relocated from the air twice since the release. �136 RESULTS AND DISCUSSION All bighorns appeared healthy at capture. No titers to PI3, BRSV and IBR were detected in 21 samples submitted for serology. Nonhemolytic Pasteurella haemolytic~ was recovered from at least 4 of 15 ewes. All fecal samples examined contained Protostrongylus spp. larvae; counts averaged about 200 11/g feces [mean(se) counts for adults: 244(284) 11/6 feces; for lambs: 155(164) ll/g feces]. All sheep survived capture and transport, and thus far no mortalities have been detected. To date, all 17 radios have been relocated, although transmission range appears severely impaired on 4 collars. Most of the remaining individuals have been identified at least once during ground observations made since the release. During the first 2.5-3 mo after release all bighorns remained on the ranch, although some dispersal from (and return to) the release site occurred. (No~e: By late July, translocated bighorns had scattered widely, and individual sheep had contacted at least 3 other established herds occupying nearby ranges (Trinchera Peaks, Spanish Peaks, Mount Blanca). Observations made in late August indicate some of these individuals may be returning to the original ~~Iease site, or to other locations on the ranch.) Preparat: _= a draft study plan outlining short-term objectives and initial monitoring needs for this release has been delayed, and will not be completed until internal problems with a cooperative agreement outlining sectional responsibilities for research and management of this transplant herd are resolved. In the interim, short-term monitoring by ranch personnel should provide useful (although limited) data on initial performance and movements of translocated sheep. Results of disease screening support other recent research (see WP2A,J4) suggesting Pasteurella spp. can be carried by healthy bighorn sheep, and that potential for disease transmission should be a consideration in planning bighorn translocations. (In addition, preliminary observations suggest dispersal of translocated bighorns and joining of these with herds established nearby may account for some apparent failures of smaller bighorn transplants in Colorado.) LITERATURE CITED Bailey, J. A. Colorado. Prepared by: 1990. Management of Rocky Mountain bighorn sheep herds in Colo. Div. Wildl. Spec. Rep. No. 66, Ft. Collins, In Press. Lb~ Michael W. Miller Wildlife Researcher �. .., - 1.) I EAR TAG COLLAR (COLORS!ID)' FREQ2 SEX AGE 3 BLUE 1 R: ORANGE/BLACK .2625 F 4.8 2 R: BLACK/I.IHITE .2375 F 7.8 3 R: BLUE .3625 F 5.8 4 --- --- M 0.8 F 0.8 5 6 R: YELLOIJ .3875 F 4.8 7 R: ORANGE .4375 F 1.8 8 V: BLUE 1 -- F 3.8 9 R: ORANGE/I.IHITE .2875 F 2.8 10 R: RED "O"/I.IHITE .7375 F 7.8 11 R: BLUE/BLACK .538 M 2.8 12 R: RED "9"/I.IHlTE .7125 F 4.8 13 V: BLUE 2 -- F 5.8 14 V: BLUE 3 F 3.8 F 0.8 .6875 F 5.8 -- F 0.8 .462 M 2.8 -- M 0.8 3.0125 F 4.8 .409 M 4.8 --- -- 15 16 R: RED "8"/I.IHITE -- 17 18 R: I.IHITE/BROIJN 19 -- 20 R: BLACK 21 R: GREEN/BLACK "M"/I.IHITE 22 .- -- F 0.8 23 R: REO .314 M 2.8 24 R: YELLOIJ/RED .611 M 1.8 25 R: BLACK .9125 F 7.8 26 V: BLUE 4 -- F 1.8 27 R: BLACK .8875 F 3.8 28 -- -- M 0.8 F 2.8 F 5.8 F 0.8 M 0.8 F 7.8 F 0.8 "F" /I.IH ITE "E" /I.IH ITE 41 V: BLUE 9 42 V: BLUE 10 ------- --- 43 44 45 V: BLUE 11 -- 46 1 R-RADIO; V-VISUAL. 2 FREQ-l72. 3 ESTIMATED BY HORN ANNULI; ASSUMED MAY BIRTH DATES. ��139 Colorado Division of Wildlife Wildlife Research Report July 1990 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~_ Project No. W-1S3-R-3 Work Plan No. Job No. 2 Period Covered: Author: ~3~A~ July 1, 1989 Mammals _ 2 Research Pron~horn Investigations Habitat Selection and Population Performance of a Pioneering Pronghorn Population June 30, 1990 T. M. Pojar ABSTRACT The population growth and distribution of the Middle Park pronghorn herd is monitored with the use of radio-collared animals. Four years of radio location data are available. Locations of radioed animals biweekly permits calculation of areas of habitation during winter (represented by January locations) and during the time of maximal dispersal (represented by June locations). The distribution and areas of habitation are presented for yearlong data for all 4 years. Growth patterns of this herd have mimicked the early stages of the theoretical sigmoid growth curve. The rate of increase for the past 3 years provides a minimally meager data set upon which to estimate the K-value for this population. ��l4l HABITAT SELECTION AND POPULATION PERFORMANCE OF A PIONEERING PRONGHORN POPULATION Thomas M. Pojar P. N. OBJECTIVE Describe population dynamics pronghorn population. and habitat use of a pioneering, expanding SEGMENT OBJECTIVES 1. Describe seasonal population. and annual distribution of the Middle Park pronghorn 2 Determine necessary 3. Monitor population dynamics of Middle Park pronghorns with: a. Ground counts to describe changes in population size. b. Ground counts to quantify population sex and age composition. sample sizes of radio-collared animals and observations to describe habitat preferences. STUDY AREA The study area is described in Pojar (1988:183-184). METHODS AND MATERIALS Seasonal and Annual Distribution The radioed pronghorns were located biweekly (with very few exceptions) since 1 January 1987. Tracking was done mostly from the ground to increase the probability of observing and identifying animals with numbered plastic collars. Fixed-wing aircraft was used if an animal could not be located after reasonable effort from the ground. Legal descriptions of animal locations were recorded to the nearest quarter mile then converted to UTM (U.S. Army 1973) coordinates for computer processing. All areas of habitation are based on minimum convex polygons, harmonic mean contours, and core areas as calculated by the program HOME (Ackerman et al. 1989). The key map used was a U.S. Department of Agriculture Forest Service Routt National Forest, Colorado, Sixth Principal Meridian, 1975 (reprint 1985). The original scale of 1:126720 was reduced to 1:230400 via photographic techniques at the Colorado State University Photo Lab. The areas plotted by the program HOME are automatically scaled according to the number of points and the area involved. Therefore, the key map (Figure 1) is to be used for general orientation and prominent geophysical features are included on the computer plots. January and June were selected to represent m~n~mum and maximum dispersion, respectively; and the plots include locations of all radioed animals. In �142 addition, plots of yearlong areas of habitation, by year, were made. Each plot has the 100, 95, and 75% minimum convex polygons and the 95, 75, and 50% harmonic mean contours. The 50% harmonic mean contour is considered the "core" area because it contains approximately 50% of the volume of observations (Tables 1, 2, and 3). Population Size and Structure During late summer and fall all animals accompanying the radioed pronghorns were counted and classified by sex and age. Herd structure estimates used in the following analysis were based on the classification with the largest sample size. The exception to this is the herd structure estimate for the fall of 1986, which was based on the sample of 47 animals trapped on 16 December, 1986. The population size estimates were made during winter when the population was concentrated on the wintering area. Counts were made from the ground using a 20X spotting scope and/or lOX binoculars. It was assumed that a count of all animals accompanying the radioed animals at this time of year yielded a total count of the population. It was possible to count the number of bucks that were 1 1/2 years old and older as a check on the earlier herd structure estimate. RESULTS Seasonal and Annual Distribution The plots generated for January and locations of 7 to 9 radioed animals, 1988. After the trapping operation in operation. Therefore, all plots 1990 are the result of locations of June of 1987 and 1988 are based on the as are the yearlong plots for 1987 and in December of 1988, there were 24 radios (January, June, and yearlong) for 1989 and 19 to 24 radioed animals. Direct comparison between areas of habitation for 1987-1988 and 1989-1990 is not possible because of the difference in number of radioed animals. Comparisons between 1987 and 1988, and 1989 and 1990 are legitimate because of a similar number of radios during each of these years. Although, the "yearlong" area for 1990 includes only January through June, the total area very likely encompasses the maximum distribution for the year. Late summer and autumn movements usually are simply a return to the winter/spring areas. Weather and snow depth influence the distribution of animals during winter. The winters of 1986-87 and 1989-90 were mild with light snow accumulation. The winter of 1988-89 was most severe with deep snow accumulation which limited pronghorn movement. The winter of 1987-88 could be classified as moderately severe. The areas (in km2) for the plot of the January distribution of animals (Figures 2 and 3) is found in Table 1, the areas for June distribution (Figures 4 and 5) in Table 2, and the areas for yearlong distribution (Figures 6 and 7) in Table 3. For proper orientation, the reader is referred to the key map (Figure 1) and the legend for the geophysical codes (Table 4). If this population is to survive in Middle Park, it seems that expansion of the wintering area will be seen as the population size increases. The large �l4 J increase in January area of habitation seen between 1989 and 1990 (Table 1) is most likely an artifact of the extremely mild winter conditions in 1990. The movement of the animals was not impeded by snow accumulation as it was in 1989. Continued monitoring of this population through varied climatic conditions will expose trends in the areas of habitation as the population increases. Population Size and Structure Early growth patterns of the MP pronghorn population have mimicked the early stages of the theoretical sigmoid growth curve (Figure 8). It took from 1979 until 1984 for the population to double the first time. It doubled again over the next 2 years. Population estimates since deployment of radio transmitter collars (1986-87) are considered to be accurate and have been used to calculate the population's rate of increase. The rate of increase (N2-N1/N1) for the past 3 years provides a minimally meager data set upon which to estimate a regression (Caughley 1977) on population size and project a K-value for this population (Figure 9). Figure 9 is based on the following observed values: Year Pop. Size Rate of Increase 1986-87 1987-88 1988-89 1989-90 80 122 160 223 .52 .31 .39 Using the regression equation from Figure 9, an estimated K-value for the population is 624 animals. This is key information for formulating long range management plans but must be used with caution since the regression is based on only 3 points. There are 2 major situations that could drastically alter the above relationship. It is possible that as a wider range of climatic (i.e. winter) conditions are manifest in the data set, the populations' response to density may be overshadowed by its response to climatic conditions. In this case, the rate of increase relationship with density would become scrambled and would not provide us with a good projection for the K-value. At this point, management objectives would have to be tied to some arbitrary decision regarding projected population density potential. A second contingency that could affect the rate of increase and, therefore, the K-value projection, is continued pioneering of the population into other parts of MP. Fragmenting of the wintering herd could release much more potential for growth than current projections indicate. Due to the gregarious nature of this species, it was possible to classify onehalf to three-fourth of the population by classifying all animals that accompanied radioed animals. Even with only 5.7% of the population radioed (1987), the herd structure sample was 52% of the population (Table 5). �144 LITERATURE CITED Ackerman, B. B F. A. Leban, M. D. Samuel, and E. O. Garton. 1989. User's manual for program HOME RANGE. Forest, Wildl. and Range Experiment Sta., Tech. Rep. 15. University of Idaho, Moscow. 79pp. Caughley, G. 1977. Analysis of Vertebrate Populations. John Wiley & Sons, NY. 234 pp. Pojar, T. M. 1988. Habitat selection pioneering pronghorn population. 181-192. and population performance of a Colo. Div. Wildl. Res. Rep. July, pp U.S. Army. 1973. Technical Manual: Universal transverse mercator grid. Headquarters, Dep. of the Army, Washington D.C. No. 5-241-8, 64 pp. ™ Prepared b~af;Jrfw Wildlife Researcher �145 Table month 1. Areas (in K(2) of habitation of January. MCP-Minimum Convex 95% MCP for Middle Park pronghorns Polygon. HM=Harmonic Mean. 75% MCP 95% HM during the 50% HM 75% HM Year 100% Mep 1987 3.2 3.2 1.1 3.9 3.2 0.24 1988 6.9 6.9 2.3 10.1 4.5 3.0 1989 3.4 2.7 2.7 6.3 3.4 1.3 1990 52.1 44.1 8.2 44.5 26.5 15.8 Table month for Middle Park pronghorns 2. Areas (in K(2) of habitation Mean. MCP=Minimum Convex Polygon. HM=Harmonic of June. during the 95% HM 75% HM 41.0 225.6 159.6 82.1 149.4 36.1 192.6 118.6 50.7 507.6 369.6 225.3 602.7 344.4 194.9 451. 5 438.1 173.1 757.2 425.3 253.4 Year 100% MCP 95% MCP 1987 170.1 150.7 1988 149.4 1989 1990 75% MCP Table 3. Areas (in K(2) of habitation for Middle MCP-Minimum Convex Polygon. HM-Harmonic Mean. Year 100% MCP 95% MCP 1987 204.6 165.6 1988 217.7 174.2 1989 603.8 522.2 1990 471. 6 331.6 Park pronghorns 50% HM yearlong. 95% HM 75% HM 50% HM 54.6 561.4 236.0 154.1 31. 5 458.2 186.5 121. 9 192.8 1554. 665.3 417.6 133.2 1007. 443.9 304.5 75% MCP �146 Table 4. Description and UTM coordinates of geophysical reference points the key map (Figure 1) and the computer plots of pronghorn distribution. REFERENCE UTM Ycord for CODE Xcord Kremmling K 381500 4435000 Town Wolford Mt. WM 381500 4442500 4.5 mi. N of K Gunsite Pass GSP 387000 4451000 12 mi. NNE of K Whitley Peak WP 373000 4464000 20 mi. NNW of K Parshall P 400000 4434500 Town Red Mountain RM 385500 4434500 2.5 mi. E of K Gravel GP 386500 4438500 4 mi. NE of K JH 389500 4437200 6 mi. ENE of K POINT Pit Jody Hill Ranch Table 5. Herd structure YEAR POP. SIZE 19861 80 1987 122 7 1988 160 1989 223 lThis year's 16 December 1986. NO. RADIO based on sample obtained X DESCRIPTION by locating radioed animals. B:D RATIO F:D RATIO SAMPLE X OF 36 77 47 59 5.7 54 77 63 52 24 15.0 40 32 108 68 22 10.2 56 50 161 72 RADIO data based on the sample of the population trapped POP. �147 Figure 1. Key map of Middle Park with geophysical features designated to assist in orientation and perspective of the animal distribution plots by the program HOME, Figures 2-7. Also see Table 4 for codes. �148 MIDDLE PARK PRONGHORN - JANUARY 1987 4442278 JH 4437588 3869313 nETERS 389948 nIDDLE PARK PROHGHORN - JANUARV 1988 4442288 ..•... tJ. JH 4434358 3839813 nETERS 39888B Figure 2. Plots from program HOME for pronghorn distribution during January 1987 and January 1988. See Table 4 for key to codes of geophysical features on plot. �MIDDLE PARK PRONGHORN - JAHUARY 1989 44481813 tJo GP JH tJo 44366513 3894113 "ETERS 3868113 "IDDLE PARK PRONGHORN - JANUARY 19913 444741BO~--------~=---------------------------------------' ...... =¥' "" .... .... ..... tJoJH 44337613 381351313 Figure 3. Plots from program HOME for pronghorn distribution during January 1989 and January 1990. See Table 4 for key to codes of geophysical features on plot. 3914613 �150 MIDDLE PARK PRONGHORN - JUNE 1987 4457810 .+.. t. GSP t. K 4429430 tlETERS 37696B HIDDLE PARK PRONGHORN 397338 - JUNE 1988 4452188 /). GSP 4431668 37985B tlETERS 399928 Figure 4. Plots from program HOME for pronghorn distribution during June 1987 and June 1988. See Table 4 for key to codes of geophysical features on plot. �151 447341B MIDDLE PARK PRONGHORN - JUNE 1989 + .. t, p 442884B 365998 "ETERS 482888 "IDDLE PARK PRONGHORN - JUME 1998 4469858 .... t,p 442686B 365118 "ETERS 48386B Figure 5. Plots from program HOME for pronghorn distribution during June 1989 and June 1990. See Table 4 for key to codes of geophysical features on plot. �152 MIDDLE PARK PROHGHORN - VEARLOHG 1987 4457818 -+- WM +++ .. ..-++ +-+i- +++ .... GP#+ IJH~.··. + .. ++-1+ .:-5- -+-. + -+ ++- I 1 I , .6+ +..,... .-++ r -+ + t::.-.~+ + .. .++ 4426290 375480 tlETERS tllDDLE PARK PHOHGHORN 488460 - YEARLOHG 1988 4454450 + .. Gt· ...t++.. +++ -*+ +.6-44 ... + +~~+..~ :tt ++.. . . .... t::.++'+ RM 4426270 376020 tlETERS 488690 Figure 6. Plots from program HOME for pronghorn distribution yearlong 1987 and yearlong 1988. See Table 4 for key to codes of geophysical features on plot. �153 MIDDLE PARK PROHGHORN - ~EARLOHG 1989 4476818 ++ F ~.... "". ~, '~ .... .. /).p Rl"i 4419620 tlETERS 365088 tlIDDLE PARK PROHGHOHN 4469810 487580 - THRU JUHE 1998 -ru~""'" ~" .... ~p 4422810 366428 tlETERS 484540 Figure 7. Plots from program HOME for pronghorn distribution yearlong 1989 and January through June 1990. See Table 4 for key to codes of geophysical features on plot. �154 300 PREDICTED - .••••• 250 200 z c: CIJ r ~ 0.998 0 :::I: (!J z 150 0 c: a.. u.. 0 c: 100 w CD ~ ::::J Z 50 o 1974 1976 1978 1980 1982 1984 1986 1988 1990 Figure 8. Growth pattern of the Middle Park pronghorn population from 1974 thru 1990. �1)5 1 0.8 y=0.555-0.00089x Q) ~ 0.6 ~ (.J c:: '0 Q) 1ti 0.4 a: K 0.2 100 = 624 • 200 700 Population Size Figure 9. Least squares regression of observed rate of increase for the Middle Park pronghorn population, 1987-89. ��Colorado Division Wildlife Research July 1990 157 of Wildlife Report JOB PROGRESS State of ~C~o~l~o=r~a~d~o~ _ Project No. Mammals W-lS3-R-3 Work Plan No. ~3~A~ Job No. _ 4 Period Covered: Author: REPORT Research Pronghorn Investigations Statewide Pronghorn Management Plan July 1, 1988 - June 30, 1990 T. M. Pojar ABSTRACT Some very preliminary efforts were made toward development of a statewide pronghorn management plan. These efforts involved meetings with the Mammals 2 Research Leader and appropriate State Wildlife Managers for direction and format of the management plan. A memo as drafted requesting information from Regional Wildlife Biologists on the current status, biological potential, and biopolitical constraints on pronghorn populations' from all regions of the state. Further progress on this project is contingent on organizational commitment and direction from top administrators. Prepared bYY/k;;J ~ (})~~ Thomas M. P jar Wildlife Researcher ��159 Colorado Division of Wildlife Wildlife Research Report July 1990 JOB PROGRESS REPORT State of Colorado Project No. W-IS3-R-3 Mammals Research Work Plan No. 6A Mountain Lion Investigations Job No. 1 Mountain Lion Population Period Covered: Author: Dynamics July 1, 1989 - June 30, 1990 A. E. Anderson Personnel: See acknowledgments Abstract Progress on the manuscript, "The puma on Uncompahgre Plateau, Colorado", is briefly summarized. Statistical analyses and preparation of figures are nearly complete. Work has begun on writing the first draft. ��161 MOUNTAIN LION POPULATION DYNAMICS Allen E. Anderson P. N. OBJECTIVE To assess the effects of sport hunting on mountain lion populations. SEGMENT OBJECTIVE To prepare final reports for publication. ACKNOWLEDGMENTS Most statistical analyses were performed by Dr. D. C. Bowden, Department of Statistics, Colorado State University, Fort Collins. N. McEwen produced or supervised CSU Graphics Department personnel in the production of most of the figures mentioned. D. Masden, Inventory Biologist, Southwest Region, assisted with mapping relative average densities of mule deer and elk on winter ranges of Game Management Units 61 and 62. M. Roelke and her colleagues from the Florida Panther Biomedical Investigation and the National Institute of Health kindly provided their information on Uncompahgre Plateau puma hematology, genetics and spermatozoa. METHODS AND MATERIALS Between April 16, 1981, and April IS, 1988, 57 puma were captured and 49 were fitted with radio collars and located from the air at 6-8 day intervals using the Universal Transverse Mercator (UTM) system. General methodology was described in Anderson (1983). Following a computer-aided validation of 3,117 aerial locations, we used the HOME RANGE personal computer program (Ackerman et al. 1989) to test the assumption of the independence of aerial locations, select 2 specific estimator(s) of home range size and utilization, and calculate home range size and utilization with those estimators. Additional programs and graphs were written in SAS. These included graphic exploration of (1) overlap of home range where the proportion of overlap was measured with an electronic planimeter and (2) seasonal shifts in home ranges by individual puma using the total number of locations. A nongraphic analysis of the spatial patterns of puma locations was made with the multi-response permutation procedure (Mielke and Berry 1982) which tests for temporal differences in the distribution of locations. Differences in mean monthly elevations of the locations were compared graphically with 95% confidence intervals of individual puma about the means. Published estimates of survival in our sample of Uncompahgre Plateau puma (Anderson et al. 1989) were being elaborated as the fiscal year ended. An index to puma activity was obtained by calculating mean distances consecutive distances over 6-8 day intervals by sex and season. between �162 Possible interactions between puma pairs was indicated by the mean (± SD) distance between their near-simultaneous aerial locations. Body weights and measurements were described statistically and linear mUltiple regression equations developed to predict body weight from body measurements for each sex. For comparative purposes, blood serum and cellular constituents and some morphological characteristics of the spermatozoa were described statistically. Some genetic characteristics were tabulated. Based on capture-recapture measurements, I calculated approximate growth rates in body weight, body length, and chest girth for 4 male and 3 female puma over growth periods 2-27 months in length. Dispersion of 13 young puma from their known or presumed natal areas were mapped and described statistically. Sightability of puma by humans was inferred from questionnaires returned by 18 of 40 homeowners residing in Log Hill Village, an upscale home development encompassing about 8 km2. There were, at various times, 2-6 radio-collared puma whose inferred home ranges impinged upon or enveloped the development. I summarized damage claims paid and sex and age class of livestock killed by puma from 1 year prior to the beginning of the study to about 1 year beyond the study. I mapped the site of each paid damage claim. I mapped the spatial relationships between the relative numbers of deer and elk and the total number of aerial locations of puma on Uncompahgre Plateau winter range, 1982-88. We are currently considering using the population model by Barrett (1987) to gain some insight into the population dynamics of Uncompahgre Plateau puma. The narrative description of the study area environment and its puma population was augmented by maps of its vegetation, topography, land status, Game Management Units and drainages and tabulations of puma, deer, bobcat, and coyote kills. RESULTS AND DISCUSSION Status of Manuscript First drafts of the "Introduction" and "Description of the Population and Its Environment" sections of the manuscript entitled, "The puma on Uncompahgre Plateau, Colorado" are underway. The aim is to produce a CDOW Technical Publication to appear in 1991. About SO tables and most of 30 figures are complete. The number of tables and figures are approximate because some deletion, additions, or combinations are likely. Except for additional work on analysis of puma survival rates and possible simulations with a population model (Barrett 1987), all planned data analyses have been completed. I abandoned the attempt to assess habitat selection within puma home ranges because of lack of time. In any case, use of home range to determine what �163 habitat is available 1990:201). is now considered a source of bias (White and Garrott Home Range, a Comment It is likely that neither of the nonparametric estimators used (minimum convex polygon, harmonic mean) actually measures size of home ranges but rather provide useful indices to size (Beier and McCullough 1990:17). There are some instances to be described in the CDOW Technical Publication which suggest that such indices are useful. In one instance, the harmonic mean (0.95) boundaries of 2 mature males essentially coincided for over 2 years. Yet the mean elevation of the younger male's locations were lower (P < 0.05). Proportionally more locations of the young male occurred on the lower slopes of large canyons. LITERATURE CITED Ackerman, B. B., F. A. Leban, M. D. Samuel, and E. O. Garton. 1989. User's manual for Program HOME RANGE. Second Ed. Tech. Rept. 15, Forestry, Wildlife and Range Exp. Sta., Univ. Idaho, Moscow. 79pp. Anderson, A. E. 1983. Program Narrative Proj. 45-01-503-15050, Work Plan 6, Job 1. Mountain lion population dynamics. 7pp. (+3 tables and Appendix lA). Anderson, A. E., D. C. Bowden, and D. M. Kattner. 1989. Survival in an unhunted mountain lion (Felis concolor hippolestes) population in southwestern Colorado. pp. 57 in R. H. Smith, Ed., Proc. 3rd Mtn. Lion Workshop, Dec. 6-8, 1988, Prescott, AZ, Arizona Game and Fish Dept., Phoenix. 88pp. (Abstract) Barrett, R. H. 1987. Population model for mountain lion in California. Dept. Forestry and Resource Manage. Univ. California, Berkeley. 10pp + Appendix. Beier, P., and D. R. McCullough. 1990. Factors influencing white-tailed activity patterns and habitat use. Wildl. Monogr. 109. 51pp. deer Mielke, P. W., Jr., and K. J. Berry. 1981. An extended class of permutation techniques for matched pairs. Commun. Stat. 11:1197-1207. White, G. C., and R. A. Garrott. 1990. Analysis of wildlife data. Academic Press, Inc., New York. 383pp. Prepared by /dLt.."-e f(j 'C=" Ci?7vfeWtr1(./ Allen E. Anderson Wildlife Researcher radio-tracking ��165 Colorado Division of Wildlife Wildlife Research Report July 1990 JOB PROGRESS State of ~C~o~l~o~r~a~d~o~ _ Project No. Mammals Research W-lS3-R-3 Work Plan No. Job No. ~8~A~ _ 1 Period Covered: Author: REPORT Small Carnivorous Development Procedures Mammal Investigations of River Otter Reintroduction July 1, 1989 - June 30, 1990 T. D. I. Beck Personnel: K. Buege, L. Malville, J. White, G. White ABSTRACT Twenty river otters (Lutra canadensis) were received from Oregon in 1989. Fourteen were eventually released into the Dolores River, bringing the total released in 2 yrs to 19. Two animals died soon after release. A new prototype radio transmitter was used with variable results. Modifications were made on the system during the year, both in electronics and surgical procedure. Dispersion of river otters in the Dolores and San Miguel Rivers is widespread. Increased dispersal appeared stimulated by the reduction of river flows from 78 to 20 cfs, although definitive support for this position is lacking. No reproduction was documented in 1990. Crayfish (Orconectes virilis group) studies involved a removal test and a mark-recapture test. Results suggest further efforts on mark-recapture are warranted. Minimum adult crayfish densities were 2.75/sq m for the removal study area and an estimated 3.l/sq m for the mark-recapture area. These densities would produce 490 kgjha wet weight of adult crayfish. ��167 DEVELOPMENT OF RIVER OTTER REINTRODUCTION Thomas PROCEDURES D. I. Beck P. N. OBJECTIVE Develop procedures for river otter reintroductions in Colorado and establish a self-sustaining population of river otters from which to collect river otters for future translocations. SEGMENT up to 20 river otters OBJECTIVES 1. Introduce into the Dolores 2. Monitor all river otter release past reintroductions. 3. Develop techniques to monitor survival, reproduction, dispersal of river otters after reintroduction. sites in Colorado METHODS Dolores River drainage. to evaluate success dispersion, of and AND MATERIALS River Map Our river map developed in 1987 was found to be in error. The cause of the error was that we started measuring from the confluence with the San Miguel and used RM 58 for the confluence based on an earlier report from the U.S. Fish & Wildlife Service. Biologists for BioWest were working below the San Miguel and obtained new topographic maps and remeasured the river from the Colorado River to Slickrock. We combined their map with ours and altered the measurements accordingly. Dolores River Release River otters were captured in Oregon by Oregon Dept. of Fish & Wildlife personnel under the direction of John Thiebes. The traps used were a new design cage-type trap developed by Oregon personnel. River otters were placed in transport cages (41 X 41 X 76 cm) for shipment to Durango, CO, via commercial airlines. All river otters were shipped at 0700 (PDT) and arrived at destination at 1400 (MDT). When possible the river otters were taken directly to Cortez Animal Clinic for radio transmitter surgery and subsequently released into the Dolores River the same evening. At times it was not possible to schedule surgery on such short notice and then river otters were kept in holding pens (2.6 X 5.2 m) with access to food and water until a surgery time could be arranged. A new radio transmitter system was tried in 1989. In 1988, 5 river otters were released with Telonics Model 400 intraperitoneal implants. These implants were 95 mm long and 32 mm in diameter, weighing 110 gms. Because of concerns with the potential physiological impacts of such a large radio transmitter we worked with AVM Equipment Co. to develop a smaller unit that could be placed subcutaneous along the back. The prototype transmitter was �168 52 mm long and 16 mm in diameter with a 195 mm long whip antenna which also was placed subcutaneously. The AVM system weighed 22 gms. The initial electronic performance required was 50 bpm receivable at 250 m for 24 months. All transmitters were gas sterilized at least 10 days prior to surgery. River otters were transferred from transport boxes to a squeeze box at the clinic. Immobilization was accomplished with intramuscular injection of ketamine (100 mg/ml) and xylazine (20 mg/ml) at a dose rate of 15 mg ketamine per kg of animal. The transmitter was placed along the dorsal line between the shoulders. A 2-3 cm incision was made at that point and then a pocket was pushed in to make space for the transmitter. A 1 cm incision was made along the dorsal line about 200 mm behind the transmitter pocket. Blunt sponge forceps were pushed up under the skin to the anterior incision where the antenna was grasped and pulled along the back. Both incisions were closed with subcuticular stitches and super glue. Each river otter was tagged with a Monel #3 metal tag in the web between 2 front toes and measured for total length; tail length; neck, chest, and head girth; and weight. All injuries were recorded. Laboratory checks were made of hematocrit, white blood cell count, and fecal parasites. Most river otters were released into the Dolores River within 3 hours of surgery. A few were kept in large holding pens for observation and/or antibiotic treatment. One juvenile female river otter was kept for 2 weeks for a feeding study. Radio tracking was sporadic during this segment because of personnel problems and extremely low water. Radio tracking was primarily conducted from a canoe and on foot. McPhee Dam releases were reduced to 20 cfs on 1 March, and this precluded canoeing the upper 65 miles of the study area. All locations of river otters were recorded to the nearest 0.1 mi. Crayfish Studies Two separate studies were conducted in efforts to estimate adult crayfish densities in the Dolores River. A removal study was conducted at RM 144.7 between 25 and 28 July. The purpose of the study was to look for obvious trap biases by crayfish size and/or sex over time as well as assess the utility of a removal study for density estimates. The study stretch was 30 m wide (the river width) and 30 m long. Wire crayfish traps were placed in a 5 X 5 grid and baited with a commercial crayfish bait. Traps were checked once each day for 4 days. The following data were collected for each crayfish: sex, weight, carapace length, trap location, trap day. All captured crayfish were removed to an area 2 mi upriver and released. Based on the results from the removal study, a mark-recapture procedure was attempted. It was decided to mark each crayfish with a mark to designate each of 3 days rather than apply a unique mark to each of approximately 2,000 crayfish. This procedure is less satisfactory than a unique number for each animal but is much faster and cheaper. So it was decided to try the simpler procedure before the more complicated one. We again used a 5 X 5 grid with 25 baited wire traps; this time at RM 149.4. Traps were checked each of 4 days with the following data recorded: sex, carapace length, trap location, trap day, and capture history. All crayfish caught on Day I were marked by punching out a quarter-circle section from the outer ramus of the uropod on the right side of the animal when viewed dorsally. A paper punch was used to clip the ramus. All crayfish caught on Day 2 had a quarter-circle section removed from the outer ramus of the uropod on the left side. All crayfish �169 caught on Day 3 had a 5 mm scratch mark etched into the carapace with a triangle file. Population estimates were derived from several procedures through use of Program Capture. All estimates were conducted by G. White, Colorado State University. RESULTS AND DISCUSSION Dolores River Map The new map work indicated a 6.5-mi error in the old map. The confluence of the Dolores and San Miguel Rivers occurs at RM 64.5 rather than RM 58. All maps above the confluence have been corrected and all data collected in previous years has been corrected to the new river mile locations. Copies of the new maps were sent to all cooperators. All readers who have reports dated prior to 1 August 1990 should be aware of the inaccuracies in river miles. Merely add 6.5 to the old mileages and they will be corrected. Dolores River Release We received 20 river otters from Oregon between 21 August and 22 October 1989. Two juvenile males were dead on arrival at Durango. An adult male suffered from a heart murmur and high WBC and died 3 days after arrival while in the holding pens. A juvenile male was extremely lethargic upon arrival and never recovered from the anesthesia. An adult female, lethargic on arrival, was kept in the pens for 3 days before she died of unknown causes. Fourteen river otters were released into the Dolores River at RM 146.7 (Table 1). Nine were females; thus bringing our cumulative release total to 10 females and 9 males. One female, RO-28, died within 2 weeks of release. She had been diagnosed with anemia, elevated WBC, and elevated temperature upon arrival in mid-October. Necropsy indicated no fat reserves and a completely empty stomach and intestines. An adult male, RO-32, was found dead of starvation along Colo. Hwy. 666 in mid-December. He was at least 6 airline miles from the river and nearly 250 m higher in elevation. After release at RM 146.7 he moved upriver to RM 152.5 the first day; then downriver to RM 132.5 during the next week. He probably died around late Nov. as all the ponds froze up then. The closest point to the river was RM 169.5 so he apparently went upriver 37 mi before climbing out of the canyon. River otter scat found near the ponds along Hwy. 666 indicated he had been feeding on crayfish. Necropsy indicated severe emaciation. RO-2l expelled her radio transmitter, probably because of a suture failure. Performance of the prototype transmitters was variable. A weakness discovered early in the season was that the antenna wire was too thin and was either breaking or coiling up around the transmitter. However, some of the thin-wire units performed adequately. Only 4 thin-wire units were released; subsequently all transmitters were rebuilt with a heavier wire antenna. It became necessary to place a tear-drop bead of epoxy on the end of the heavywire antenna to prevent the antenna from puncturing the skin. Performance of the prototype transmitters was variable, with above ground transmission distances of 250-400 m. While acceptable, we discovered that transmission from underground (bank beaver dens) was severely restricted, varying from 30-70 m. Since the released river otters spend so much time in the beaver dens, it became critical to increase transmission distance. A new �170 prototype was developed with a slightly larger battery and greater output. We still anticipate a battery longevity of 23 months. The new unit measures 66 mm long X 15 mm diameter with a 195 mm whip antenna and weighs 23 gm. Field tests indicate the underground transmission distance should be at least 200 m, which is quite acceptable, with a few units transmitting to 400 m. Personnel problems, combined with conflicting new assignments, resulted in little radio tracking during the winter season. Unfortunately, this year was also a very low snowfall year, resulting in no spring runoff below McPhee Dam. The operators of McPhee Dam lowered the releases to 20 cfs on 1 March 1990, which made canoeing of the upper 65 mi of the study area nearly impossible. Surveys in the lower canyons in March, April, and May indicated river otters were spread throughout the Dolores River at least to the San Miguel River. It is reasonable that the sudden reduction in river flows from 78 to 20 cfs triggered movement downstream in anticipation of the river drying up. Numerous sightings of river otters have been reported from the Colorado River downstream to Lake Powell, but it is unknown if these are from the Dolores River release or possibly dispersal from other release sites. Unfortunately, the only female released in 1988, RO-5, has not been located in 1990 so her reproductive status is unknown. At least one male, RO-7, has moved upriver into McPhee Reservoir. Another male, RO-4, missing since March 1989, was located on 31 July 1990 in the San Miguel River approximately 43.1 mi upriver from the Dolores River and 125.3 mi from the release site. An adult female, RO-25, had moved downstream into Slickrock Canyon. She was found dead of natural causes in late July 1990 at RM 107.7. She was not present at that site 3 weeks previously and the radio transmitter was performing well. The widespread dispersion of the river otters strongly supports the need to release at least 30 animals in one area. Since fish and crayfish appear to be abundant and bank cover, both vegetation and beaver dens, is abundant it is doubtful if the cause of dispersal is habitat, although there is no definitive data. RO-9 was kept in captivity for 2 weeks in an attempt to assess food habits estimates from scats. The data collected was of limited utility. Her intake varied from a low of 50 gms of crayfish (tails only) to 1350 gms of trout (Oncorhynchus gairdneri and Salmo trutta). Soon after the beginning of the feeding trials we were forced to use the adjacent pen for holding other river otters. The greatly increased human activity may have caused a significant reduction in food consumption. RO-9 then bit the employee feeding her and had to be euthanized in order to check for rabies. The feeding trial is worthwhile but will only be repeated with one of the last animals to be handled in 1990. During the first week of the trial, RO-9 was ingesting food amounting to 35-40% of her live weight daily. �171 Table 1. River otters released in the Dolores River, co. 1989. ID Length (em) Total Tail Circumference (em) Head Neck Chest Tag if Origin Sex Wt(kg) RO-9 F 3.9 91 36 22.5 21.0 29.0 9 Columbia R. , OR RO-12 M 5.2 95 38 24.0 23.0 33.0 12 Tenmile Lake, OR RO-15 M 8.3 116 46 26.0 27.0 41.0 15 Tenmile Lake, OR RO-17 M 10.9 125.5 47 25.5 30.5 47.0 17 Columbia R. , OR RO-21 F 5.9 104 37 24.0 26.0 40.0 21 Tenmile Lake, OR RO-22 F 5.4 98 nd nd nd nd 22 Willamette R. , OR RO-23 F 8.3 113 41 25.5 29.5 44.5 23 Willamette R. , OR RO-24 M 4.8 94 33 23.0 23.0 35.5 24 Columbia R. , OR RO-25 F 7.4 114 44 24.0 25.5 39.5 25 Tenmile Lake, OR RO-26 F 7.3 108 41 24.0 27.0 42.0 26 Willamette R. , OR RO-27 F 4.1 93 nd 22.5 21.0 33.5 27 Marion Fks Hatch, OR RO-28 F 4.6 99 38 21.5 21.5 32.0 28 N Umpqua R. , OR RO-29 F 6.1 104 38 23.5 24.0 32.0 29 N Umpqua R. , OR RO-31 F 7.5 117 43 24.0 26.0 37.5 31 Willamette R. , OR RO-32 F 8.3 115.5 42 27.0 28.0 40.0 32 Deschutes R. , OR Crayfish Studies During the last 20 years there have been many studies throughout the world attempting to estimate crayfish numbers by means of trapping programs. The variability in study sites is matched by the variability of results. When using any mark-recapture program the assumptions on equal catchability are critical so many workers have attempted to quantify capture biases by sex, season, and capture method. Unfortunately, there are no general patterns. While most authors suggest a trap bias for large males (often exceeding 75% of total catch) (Momot and Gowing 1983, Brown and Brewis 1978, and many others) there are instances of trapping being more selective for females (Brown and Bowler 1977). Seasonal differences can be quite strong because of reproductive requirements. This is why we did our studies over a short period �172 (5 days) during late summer after the major molting periods. A complication with short studies is that all crayfish are not active every night and that perhaps certain groups of crayfish have coinciding activity periods (Hazlett et al. 1979). Thus, one could capture and mark a large number of animals on Day 1, then rarely see these for 2 days only to see large numbers of recaptures of Day 1 animals on Day 4. The removal study was conducted first to check for obvious biases in capture rates. The initial assumption was that large males would dominate the early catch but once removed from the system, females and small males would show up later. Based on earlier work on Orconectes virilis (Hazlett et al. 1979), we were confident that all crayfish within the study reach were within easy reach of a baited trap. Since we were concerned with immigration into the study reach, we planned the study for 5 days as we optimistically figured to catch nearly all the crayfish within that time. After 4 trap nights we had captured and removed 2,470 crayfish (1,283 male, 1,187 female). No diminution in catch occurred through time: 633 on day 1, 532 on day 2, 678 on day 3, 627 on day 4. There was no strong trend based on sex, as percentage of males for the respective days was 55.5, 47.2, 51.3, 53.1. There was no change in length-frequency curves for either sex over the 4 days, thus no identifiable trap bias based on size. There was no evidence that significant immigration into the study reach occurred. Number of captures in Row 1 (upstream row) was 115, 158, 153, and 115 for days 1 through 4. Number of captures in Row 5 (downstream row) was 80, 47, 174, and 128 for days 1 through 4. There was surprising uniformity in catch by row (541, 464, 501, 535, 429 for 1-5, respectively). There did appear to be a tendency for the mid-stream column of traps to fish less effectively than the more shoreline traps, but the traps closest to the shoreline did not differ from the next column in toward midstream. More detailed descriptions of possible trap bias are being prepared by G. White. Our tentative conclusions from this study were: 1) no observable trap bias based on size or sex, 2) we certainly did not trap out the adult crayfish population, 3) the minimum known density of adult crayfish in the study reach was 2.75/sq m. This density exceeds all reports that I have located for rivers in N. America and Europe (range 0.131.8) but is not directly comparable because other workers are estimating density over a much larger area with heterogenous habitat. Our study reach was relatively uniform in habitat. The mark-recapture study was conducted upriver in a similar habitat but with slightly less boulder on the bottom. The same grid system was employed. During 4 nights of trapping 1,390 individuals were caught, of which 343 were recaptured at least once. Detailed analyses are still being conducted by G. White, but initial runs through Program Capture resulted in promising estimates. More work needs to be done on capture heterogeneity, and in 1990 a study will be conducted using uniquely marked individuals. The Null, Jacknife, and Darroch estimators produced similar results with surprisingly small 95% confidence intervals. The General Removal Method produced an estimate 3 times greater than the others. For comparative purposes, G. White (pers. comm.) suggested the Jacknife method as a reasonable estimate. The estimate was 2,795 with the 95% C.l. being 2,673-2,917. This would provide a minimum adult crayfish density of 3.1/ sq. m. The average size of the 2,470 crayfish weighed in the removal study was 15.75 gms. At a density of 3.1 adults/sq. m., the standing stock biomass of adult crayfish would be 490 kgfha (437 lb/ac). That amounts to 31,098 adultsfha or �173 12,585 adults/ac. Thus,it appears that crayfish can support numerous predators in the portion of the Dolores River between RM 173 and 130. LITERATURE CITED Brown, D. J., and K. Bowler. 1977. A pcpu l.a t Lon study of the British freshwater crayfish Austropotamobius pallipes (Lereboullet). Freshwater Crayfish 3:33-49. Brown, D. J., and J. M. Brewis. 1978. A critical look at trapping as a method of sampling a population of Austropotamobius pallipes (Lereboullet) in a mark and recapture study. Freshwater Crayfish 4:159164. Hazlett, B., D. Rittschof, and C. Ameyaw-Akumfi. 1979. Factors affecting daily movements of the crayfish Orconectes virilis (Hagen, 1870) (Decapoda, Cambaridae). Crustaceana, Suppl. (Leiden) 5:121-130. the Momot, W. T., and H. Gowing. 1983. Some factors regulating cohort production of the crayfish, Orconectes virilis. Freshwater BioI. 13:1-12 . .f/' () f A~ n Prepared by ~7?p? ,i'/.:/' Thomas D. I. Beck Wildlife Researcher ��Colorado Division Wildlife Research July 1990 175 of Wildlife Report JOB PROGRESS State of Project REPORT Colorado No. W-IS3-R-3 Mammals Research Work Plan No. 9A Elk Investigations Job No. I Impact of Elk Winter Production Grazing on Livestock and Work Plan No. 3 Job No. S Period Covered: Authors: Personnel: July 1, 1989 - June 30, 1990 N. T. Hobbs, D. L. Baker, G. Bear M. Miller, J. Miller, R. Reid, L. Carpenter, C. Woodward, B. Seely, H. Seely, L. Lovett B. Gill, B. Petch, ABSTRACT Elk grazing during winter influenced cattle performance on sagebrush-grassland range during spring. Weights of cows and calves at the end of the spring grazing season declined in response to increasing intensity of winter and spring grazing by elk. Reductions in spring weights resulted from reduced rates of gain. Cattle performance declined annually during 4 study years. We attribute annual effects to the combined influence of cattle .grazing and, drought on the productivity of the site we studied. However; 'the magnitude of the effect, of el~ grazing Aid not; ,de-eend on year, sugge st Lng that no cumulative effects of elk grazing- were prese.nt;' Analysis of data' from year 4 on vegetation responses is in progress. ��177 IMPACTS OF YINTER GRAZING BY ELK ON CATTLE PRODUCTION N. Thompson Hobbs Dan L. Baker P. N. OBJECTIVES 1. To test the hypothesis that elk grazing during winter influences the productivity and botanical composition of herbage on sagebrush grassland ranges during spring. 2. To test the hypothesis that elk grazing during winter influences the body weights and rates of gain of cows and calves using sagebrush grassland ranges during spring. METHODS AND MATERIALS Study Area We conducted experiments on the Little Snake Wildlife Management northwestern Colorado (township 9 north, range 95 west, sections area is about 35 km (19 mi) north of Maybell, Colorado on County Although this area does not typically contain high concentrations during winter, it is representative of areas that do have those densities. Area in 9, 10). The Road 19. of elk high Topography of the area includes level ridge tops, rolling hills, and deep gullies, ranging in elevation from 1,800 to 2,000 m (5,900 to 6,600 ft). Aspects are southern and southwesterly with an average slope of 15 degrees. Soils are generally sandy and sandy loam. Climate of the area is dry and cold. The growing season averages only 81 days. Annual mean temperature is 6.06 C (42.9 F). Annual precipitation averages 27.5 cm (12.5 in). Vegetation is dominated by big sagebrush (Artemisia tridentata) with an understory predominated by needle and thread (Stipa comata), western wheatgrass (Agropyron smithii), Indian ricegrass (Oryzopis hyrnenoides), Junegrass (Koleria cristata), and cheatgrass (Bromus tectorum). Important forbs include wallflower (Erysimum asperum), peppergrass (Lepidium perfoliatum), silver lupine (Lupinus argenteus), and scarlet globe mallow (Sphaeralcea coccinea). Experimental Design We observed effects of elk grazing on forage and cattle responses in a randomized complete block design with four levels of elk density (0 elk/km2, 8 elk/km2, 15 elk/km2, and 31 elk/km2) and three replications per level. There were three blocks, each consisting of four pastures. Each pasture within a block was stocked with one level of elk density such that each block contained all levels. During year 1, the twelve available pastures were blocked by pretreatment biomass of perennial grasses with the four lowest grass biomass pastures forming one block, and the four highest grass biomass pastures forming a second block, and the remaining four pastures serving as the third block. The four levels of elk density were randomly assigned to pastures within each block during year 1. �178 Procedures We stocked pastures with elk in December and January 1987-89. Average date of release into pastures was January 3. All elk were removed from pastures during April 10-20. We introduced 7 cow-calf pairs and one dry heifer into each pasture on May 9, 1990, and removed them 5 weeks later. This represents a departure from the first two study years when animals remained in the pastures for 6 weeks. However, a marked reduction in forage production during the 1988-1989 growing seasons compelled us to reduce the stocking rate during 1990 in order to preserve consistent utilization rates in control pastures. With the exception of addition of new heifers and other replacements required by death losses, etc., cows during year 4 were the same animals we observed during year 3 and were assigned to the same pastures they were in previously. We observed the birth dates of all calves and weighed them to the nearest 0.05 kg immediately after birth. Cows and calves were weighed to the nearest 1 kg when they were introduced to pastures and were reweighed 5 weeks later when they were removed. We estimated canopy cover of herbs shrubs immediately after removing cattle from pastures. Cover was estimated from the summed length of interception by each plant along 30, l2-m transects randomly placed in each pasture during year 1. We estimated standing crop, productivity, and utilization of forbs, perennial grass, and annual grasses by harvesting samples from 40 pairs of 0.70 m2 plots in each pasture on each of three sample dates. Pastures were sampled immediately after the elk were removed (April 27-29), at the midpoint of the spring grazing season (May 30-June 1), and at its end (June 30-July 2). Samples were dried at 60 C for 48 hrs, separated by hand into live and dead, and weighed to the nearest 0.01 g. We used a repeated measures analysis of covariance for a randomized complete block design to analyze weight responses of cattle. Calf birth weight was used as a concomitant observation for calf weights out of pastures and for rates of gain. Cow weights into the pastures were used similarly for adult cattle and heifers. We believe that this analysis offers conservative tests of hypotheses because any cumulative, depressing effect of treatment on the covariate would tend to make it more difficult to detect significant differences among treatments. However, we are in the process of consulting with Dave Bowden (Statistics Department, Colorado State University) on the details of this analysis to assure our statistical approach is reliable. Future analyses will reflect these consultations, and may offer somewhat different results than we report here. RESULTS All results described in this report are preliminary and are subject to revision as analyses are checked for accuracy. Here, we report our findings to provide a timely summary of progress, but we are obliged to thoroughly revisit them later. �179 Effects of Elk on Cattle Performance Elk grazing during winter influenced the performance of cattle during spring. Averaged over 4 study years, weights of calves at the end of the spring grazing season declined in direct proportion to the winter/spring density of elk (Figure 1, linear effect P - 0.023). End of spring weights of calves in the high density treatment averaged about 8 kg less than those in the control (Figure 1, control vs 31 elk/kmz P - 0.021). The average weights of calves (adjusted for differences in birth weight) in the control were greater than the average weights of calves in pastures stocked with elk (Figure 1, control vs. treatment P - 0.042). However, differences in calf weight between the low density elk treatment and the control were small (about 1 kg) and were not significant (P - 0.20). Averaged across treatments and controls, calf weights tended to decline during years 3 and 4 relative to the first 2 study years (Year effect P - 0.0001). However, the magnitude of the effect of elk grazing was consistent across all 4 years of the study (Year x Level P - 0.479). That is, the effect of elk grazing did not intensify as a result of "cumulative" effects as the study progressed. Effects of elk grazing on end of spring weights of calves reflected differences in average daily gain (Figure 2, linear effects P - 0.01). However, the rates of gain in the low and medium density pastures were quite similar to those in the control, suggesting threshold effects of elk grazing between the 15 and 31 elk/kmz levels. We will compare threshold with linear models in future analyses. We observed significant differences among years in calf rates of gain (year effect P - 0.0001), but saw no year by treatment interaction (year x level P - 0.81). This once again suggests that the magnitude of the effect of elk grazing remained constant over time and did not accumulate over study years. Calf birth dates were delayed in response to all levels of elk grazing (Figure 3, control vs. 8 elk/km2 P - 0.03, control vs. 15 elk/km2 P - 0.01, control vs 31 elkjkm2 P - 0.06). However, this effect was not linear and tended to reach a maximum at the 15 e1k/kmz level (Figure 3, quadratic effect P - 0.02). Responses of cows to elk grazing resembled those of calves, but higher interanimal variability tended to obscure the significance of treatment. Average weights of cows at the end of the spring grazing season (adjusted for differences in pre-season weights) declined in proportion to elk density, but this effect only approached statistical significance (linear effects P 0.07). Similarly, rates of gain declined as elk density increased, but this response was highly variable (linear effects P - 0.07). Cow weights at the end of spring as well as spring rates of gain were strongly influenced by year (P < 0.0001). However, the size of the effect of elk density on cattle performance did not change with year for either response (P > 0.89) suggesting no cumulative effects were operative. Effects of Elk on Vegetation Effects of elk on vegetation production, years are currently being analyzed. condition, and trend after 4 study �180 DISCUSSION A tendency for elk grazing during winter to reduce the performance of cattle during spring has clearly emerged in our studies after four years. We can be quite confident that intense elk grazing during winter and spring harms the performance of calves during spring and can be reasonably certain of similar effects on cows. Prepared by N.r:::h-tt vLVWildlife Researcher q_~,f'_(~ Dan L. Baker Wildlife Researcher �181 1.0 >: jg 0.9 0, /\ " 0.9 r: 6 al •.. 0.8 :::J 1i) as a... .S 1.0 = :; (1] 32 ._a u .::t::. * 0.8 Q) •... ::l Ui &: 0.7 0.7 .S c c '113 '(i3 o o -o 0.6 0.6 ~ 0.5 ~ 0.5 C/) - co o <U __J 0.4 0.4 0 5 10 15 20 25 30 35 Elk Density (animals/km2) iYear ! '* *::.::1 ::;:4 Means adjusted to common birth weight. OJ!" A,11.. Years control vs c::ont.ro~ va c::ont.ro~ va other. cont.ra_t. ss po Va:Lu_ Pr 3.50 1.34 0.00 11.29 10.28 1.76 0.1106 0.2905 0.9514 0.0152 0.01B5 0.2324 > F ~~~~~~:l.e~;_~~a-:l.k/k:m! quadrat.ic:: _~~_c::t._ 1 1 1 0.03534255 0.01356235 0.00004078 0.11400822 0.1038:01473 0.01781855 Year 1 contro~ VB other_ c::ont.ro:l. va 8 _~k/kn121 c::ont.ro~ va 15 e~k/k:m c::ont.ro~ 'V's 31 e~k/k:m :Lin_ar e~~_c::t._ quadrat.ic:: _~~_c::t._ 1 1 1 1 1 1 0.00539948 0.00011359 0.000625:018 0.02083060 0.02384608 0.00297932 0.77 0.02 0.09 2.96 3.39 0.42 0.4147 0.9030 0.7757 0.1361 0.1152 0.5393 1 0.00685662 0.00556753 0.00061201 0.01070700 0.00765803 0.00000573 1.25 1.02 0.1.1 1..96 1.40 0.00 0.3059 0.3522 0.7495 0.2115 0.2817 0.9752 1 1 1 1 0.00863837 0.01124589 0.00:0185982 0.03065762 0.02071642 0.01003653 1.46 1.90 0.4B 5.19 3.50 1.70 0.2722 0.21.70 0.5127 0.0630 0.1104 0.2403 1 1 1 1 1 1 0.01606900 0.00173012 0.00027242 0.06370886 0.06685997 0.01205902 1..13 0.12 0.02 4.48 4.70 0.85 0.3287 0.7392 0.8945 0.0787 0.0733 0.39:017 1 a _~k/k:m2[ 15 _ :l.k/k:m! ~O~{rg1 V_ oont.ro:l. ~_ oth_r_ 8 _~k/k:m2 c::ont.ro~ ~_ 15 -:l.k/k:ml oont.ro:l. ~_ 31 _~k/k:m 1in __ r _~~~ct._ , quadrat.ic _~~_ct._ ! x.or contro1 :3 va oth_r_ c::ont.ro1 va 8 _:l.k/k:m2j c::ont.ro~ va 15 _:Lk/k:ml c::ont.ro1 v_ 3~ _~k/km, :Linear e~~_c::t._ ' quadrat.ic::_~~_ct.a Year 4 c::ont.ro:l. v_ ot.h.r_ \ c::ont.ro~ ~a 8 _1k/km2\ c::ont.ro~ v_ 15 .1k/k:m c::ont.ro~ v_ 31 e:l.k/k:m 1in.ar .rr_ct_ quadrat.ic:: .~~_ct.a I a, 1 1. 1 1 1 1 a, 1 Figu~e2~ Eff,ectsof ~lk,~ip~~r,-gr~ngJ?~,Jates>ot.g~i~ of"caIY~:during the spring gr~ll:!9,s.ea~ .. Dat~,PQln~.areleast sqy8(ep;rl1~$.:(LSM};,fQ(i~h pastureduring each'year~ line Show$ I;.;SM.-vallies acrcss.all years. V.erti~ :pars-= 2 standard errorsotme mean. ,. ;.,'----:-'. -..-" -- �182 - 100 100 a~ 0) 6 ~ 90 ::J en e (5 0) 80 - :-.:: 1 80 i . ~ 70 (5 "S 0 -'"'- ==fzz -; 70 1: 0 ~ - <ti (ij ::: ::J (Ij "< ;,,; ~ o ~ en o, "S 0 E 90 ~ 60 60 o ~ C/) ~ _J 50 50 0 10 5 Elk Density Year ~ _, ::-::1 20 15 OF Y:!!ars c::ontroOi vs ot.hers c:.ontro1 va 8 e1k/krn2 oC)ntro~ va 15 eJ..k/krn va c:ont.ro~ 31 eJ..k/k:m e:rr_c'ts l...i..near qu ••• clr ••• t:1.c effect.s 30 25 (animals/km2) .::_2 Means adjusted to common Contrast 35 =4 =3 birth weight. Cont.rast 55 F Va~ue Pr >- F :!!k1~ 1 1 1 :1. 1 1 326.82828197 103.66999879 153.96600527 470.57267042 448.04755462 12.91123368 6.67 2.11 3.14 9.60 9.14 0.26 0.0417 0.1961 0.1267 0.0212 0.0233 0.6261 1 1 1 1 1 1 12.28671445 3.33767567 27.54509577 26.67350990 46.75838244 1.01851203 0.42 0.11 0.94 0.91 1.59 0.03 0.5422 0.7478 0.3708 0.3780 0.2544 0.8586 1 1 1 1 1 1 16.30259696 2.40639274 2.75382664 44.61511961 46.61121821 2.51519165 0.82 0.12 0.14 2.25 2.35 0.13 0.3999 0.7397 0.7224 0.1846 0.1764 0.7341 ot.h_r_ va v_ cont.rol.. 8 eJ..k/km2 c:ontro.1. 15 _1k/k:m cont.rol. va 31 e1k/km art_ct._ l..,in_ar _rr_ct._ qu. ••• clr ••• t.1.c 1 1 1 1 1 1 94.48924391 72.27683100 7.58981980 157.59954439 116.31941128 0.58705130 7.87 6.02 0.63 13.13 9.69 0.05 0.0309 0.0495 0.4568 0.0111 0.0208 0.B323 4 c:ont.:ro.l.. ot.hers c:::ont.ro.1. B _1k/krn2 control.. 15 e1k/krn contro1 31 e1k./km _ 1!:r_c::t._ .1.i.n_ar quadrat.ic: er1!ec::t.s 1 1 1 1 1 1 356.95826295 147.32595506 229.63877726 360.52185069 319.83276786 72.74990977 5.02 2.07 3.23 5.07 4.49 1.02 0.0664 0.2002 0.1226 0.0654 0.0783 0.3510 v_ v. XS2ar • other_ con.t.:ro~ va c:ont.ro~ 8 eJ..k/km2 c::ontro.1 VEl 15 eJ..k/krn cont.:ro~ 31 eJ..k/k:m 1.in_ar e~~ect_ ef-r_c::'ta quadr ••• t.1.c ". 20~{rg1 v. oontrol. ot.hers 8 e1k/km2 'Va_iS contro.1. eJ..k/kDl control. 31 eJ..k/k:m _~r_c::t._ 1.1.,n_ar quadrat.1.c_f~_c::t._ ,,- ;;o~Erg~ ,,_ Xe!!E ". "._ ,,_ ,, Figure 1. Effects of elk winter grazing on weights of calves at the end of the spring grazing season. Data points are least squared means (LSM) for each pasture during each year. Line shows LSM values across all years. Vertical bars = 2 standard errors of the mean. �183 05/00F===============:::_:_- 05/08 ~ <i] ~ 04/28 +-- ---:=::-- __ 04/28 -==- __ ___c=-.:._ C g = ~ 04/1a-'--=-~=---=-' Ii: a:J t , u. 04/08 f5 ,------lI=--_ T 7_- __ Y 04/18 x --:" -r---:""":;::-' ----~t~: _____:_ -.~ ---=-=__ --=-"-- 04/08 Z 03/29-,===================03/29 10 15 o 5 20 25 30 35 Elk Density (animals/km2) Year -s; Contrast x1 2 OF ,"",,11 Years control vs others control vs s e~k/k~2 control vs 1S elk/km contro~ ~B 31 e1k/k~ 1.i.near effect.s quadratic effects ~~n{r~1 ~_ others contro~ va e e~k/k~2 contro1 va 15 e1k/km contro1 v_ 31 81k/k_ ~in_ar _~~_c:::t_ quadratic _~~_ct_ Xear »< :3 contro1 vs others contro~ va a _lk/km2 control ~_ 15 elk/km contro1 VB 31 e1k/k_ linear ef~_ct_ quadratic: _f~ect_ V_ Year 4control other_ control va e 81k/km2 contro1 v_ 15 e1k/km contro1 v_ 31 e1k/km l.i.nEusr 4!t~~_ct_ quadratic _~fects 1 1 1 1 1 1 cont.rast -3 ~4 SS 249.03703704 162.00000000 242.00000000 107.55555556 71.42857143 198.10678211 F Va.1ue Pr 13.09 8.51 12.72 5.65 3.75 10.41 0.0111 0.0267 0.0118 0.0550 0 ..1.008 0.0180 :>- F 10.02777778 24.00000000 1.50000000 2.66666667 0.02142857 !5.8!528138!5 0.34 0.81 0.05 0.09 0.00 0.20 0.5821 0.4031 0.8296 0.7744 0.9794 0.672!5 1 1 1 1 96.69444444 48.16666667 66.66666667 80.66666667 66.40238095 30.13852B14 6.32 3.15 4.36 !5.27 4.34 1.97 0.04!57 0.1264 0.0819 0.0615 0.OB24 0.2101 1 1 1 1 1 1 205.44444444 104.16666667 308.16666667 54.00000000 40.23809524 271.24675325 4.B5 2.46 7.27 1.27 0.'95 6.40 0.0699 0.1679 0.0357 0.3020 0.3674 0.0447 1 1 1 1 1 :1. 1 :1. Figure 3. Effects of elk winter grazing on calf birth dates. Data points are means foreachpasture during ~achyear. Line shows mean values across all years. V~rtfC$fba~¥;~'_~ndar~ errors of the mean. - ....- '." ;~<; . _-~ .. ~ <7: ::-~. .:"_~ : -""~_:;i:-_~:~"~:~-.~:~ ~?:.-~~~f::,:'-:' .- �184 460 ~~:================================~ cn450~~--------------------------------------------450 e CD .._ '< x: 440 44OTI~~--------~C-------------------------------~'- ::::l ;.t( 430 ~ 430--=o--------~------~------------------~------ cf'+-0 5410 t f -, 42O~: -+t---------~-F-" ---------'<---- K 420 410 4OO~. --===----±---.lr------=~o---~------=~---400 ~ 390: -= 390 380 ~ 380: o . Um m ~B ~ ~ 350 350 o 5 15 10 20 25 3S 30 Elk Density (animals/km2) Year ::oK X x 1 t: L .;i 2 =:___! = 3 Means adjusted to common weight into pasture. Cont.ra_t l!o~;!' OF Cont.rast. 55 F Va~u_ Pr :> F :;(eara 'VB ot.her. contro1 c::on:t.ro a, 'VB 8 _~l<./l<.rn2 'Va cont.rol.. 1..5el..l<./l<.:m 'Va c::ont..ro1 :31 _~l<./l<.m 1inear effect. quadrat.i.e::_~~_c:t._ 1 1.. 1 1 1 1 812.03046807 478.93347940 114.6032:3541 1384.67221..728 1119.6184:3059 2.1..5293548 3.44 2.0:3 0.49 5.86 4.74 0.01.. 0.1131.. 0_2043 0.5121.. 0.0518 0.0723 0.9270 1.. V!!!or others c:ont.ro~ 'Va cont.rol. va 8 e~l<./l<.:m2 v_ cont.rol.. 1..5_1l<./l<.:m c:ont.ro1 va :31 _~l<./l<.:m l..i. •..• ear e~r_c:t.1!I quadrat.i.e::e:l!:I!ect._ 1.. 1 1 1.. 1 1 0.21785646 27.0533751..4 107.23 .••. 58082 39.65761..081 1:3.47957560 1..13.59717956 0.00 0.14 0.56 0.21.. 0.07 0.59 0.9743 0.7209 0.4841 0.6662 0.8003 0.4719 5.14 2.03 1.88 7.59 6.84 0.11 0.0640 0.2036 0.2194 0.0331 0.0:398 0.7522 0.:3486 0.8:309 0.5554 0.1516 0.1287 0.7999 0.4515 0.:3978 0.7291 0.5109 0.6559 0.7399 g~~€r~1 v_ other_ _~l<./l<.rn2 c:ont.ro1 vl!Il_8 control.. va _~lc/lc:m 15 c::ont.,ro.1 'Va :31 _~lc/l<.Dl ~i. •..• _ar e-rr_c:t_ _~r.c:t._ quadrat. i.e:: X-AE 1 1 1 1 1 1 733.:39748071 290.46453972 268.:32726608 108:3.1785936:3 976.5661:3814 15.60084540 1 166.78463458 8.034449:32 ~ v_ ot.h_r_ control.. c:on:t:.rol. 'V_ 8 _1lc/l<.:m2 c:ontro.J.. 'V_ .1.5_:l.l<./lc:m 'V_ cont.ro1 _~lc/l<.Dl 31 efr_ct._ l..i.near quadrat.i.e::err_ct._ Vear ~ ot.h_r_ control. 'VB cont.rol.. 'Va 8 _~lc/l<.m2 e::o •..• t.ro~ va _~l<./lc:m ~5 cont.rol.. va _l.l<./l<.:m 31 l...i.n_ar ef~eot._ quadrat.i.e::e:l!:I!_e::t._ .1. 1.. 1 1 435.42384833 500.78900985 11.:32868318 1.0:3 0.05 0.39 2.70 3 •.1.0 0.07 1 1.. 1 l. :1. :1. 273.2:3166622 :349.:32660952 55.5420l.859 205.82058047 92.57464015 50.97447616 0.65 0.8:3 0.l.3 0.49 0.22 0.12 a, 62 .. 9268:3282 Figure 4. Effects of elk winter grazing on cow weights at the end of the spring grazing season. Data points are least squared means (LSM) for each pasture during each year. Line shows LSM values across all years. Vertical bars = 2 standard errors of the mean. �185 2 2 ,\ W 'i x x 3iE ~ >K LJ - ~ ~ ~ < ,''. '* e- 0 " - i~ CD •... :::::l 1' t~ W (/) CIl c, ,S; c: 'n; H CJ 1 ~ ,£ c 'n; 0 CJ ~ 0 ~ - (.) ::E 0 o ::E .;::: CJ) ::::J (ii :::: ;- -=CD..._ CJ) ....J ...J -1' -1 0 10 5 15 20 25 30 35 Elk Density (animals/km2) Year c< x ~ 1 2.2 ,--' =3 Means adjusted to common weight into pasture. OF contraat ~;;*€~~!FVI!& other. v_ 1 C:On.t.FO~ 8 e:1.1<:./1<:.:m2 1 c::ont.ro.1.. va :1.5el..1<:./1<:.:m 1 c:ont.ro1 va 31 e11<:./1<:.:m 1 err_ct.. l.inear 1 e~~_cta quadratic 1 ,,~~~(r!.1.. ot.h_r_ 1 v_ c:::ont.ro1 8 _l..1<:./1<:.:m2 1 control.. "a _l..1<:./1<:.m1 15 c;ontro1 _l..1<:./1<:. ••• va 31 1 l..inear e~~ec:ta 1 _~~ec:t_ quadratic 1 g~~(rg1 va other_ 1 control.. "a a el..1<:.,1<:._2 1 control.. l..!5 el../kDl 1 contra:&. va 3J..el..1<:./1<:._J.. l.in•••• r e~~_c:ta J.. quadratic J.. e~~ec:ta ,,- ~~:ttrg1 va ,,c::oftt.ro1 oth_ra 1 8 e11<:./1<:._2 1 c::ont.:ro1 va el..1<:./1<:._l.. 15 c:ont.ro.1. va el..1<:./1<:.:m 31 1 l..in_ar e~~_cta 1 quadratic: _~~_cta :1. ~g~[:r@1 "a othera :1. va a el..1<:./1<:.:m2 1 va J..5_l..1<:./1<:._1 va e11<:./1<:.:m :1. 31 1in •••• r _~~ecta 1 _~~_cta quadratic 1 cont.ro.]. contro:&. cont.ro.]. Cont.ra •• t 55 po Va1u_ Pr > 0.70495984 0.35636241 0.0994:1.263 1.30960362 1.11228462 0.00855596 3.08 :1..56 0.43 5.72 4.86 0.04 0.:1.298 0.2586 0.5343 0.0539 0.0697 0.8531 0.00006598 0.0l..803876 0.09624188 0.02434338 0.00682232 0.0964:1.649 0.00 0.:1.5 0.81 0.21 0.06 0.81 0.9819 0.7097 0.4019 0.6661 0.8182 0.4015 0.37847991 0.16770179 0.J..2706827 0.54902660 0.48000712 0.00800233 4.35 1.93 1.46 6.31 5.52 0.09 0.0820 0.2143 0.2723 0.0458 0.0571 0.77J..9 0.36275296 0.01386065 0.l..4087886 0.96478172 1.12J..99042 0.02683770 J...OJ.. 0.04 0.39 2.69 3.:1.3 0.07 0.3533 0.8506 0.5539 0.1521 0.1273 0.7936 0.22077174 0.28341587 0.04368912 0.16772162 0.07542428 0.03995186 0.64 0.82 0.:1.3 0.48 0.22 0.12 0.4548 0.4002 0.7344 0.5:1.23 0.6570 0.7455 f:;';;:/~:-'~:'~:~i~~~~ri_ar1!ec;g:_':'_'~ffi6& clciUZ~~I~iit~'~1,n (atiJ~ia]gafn.Of:Cmv$ dt,jring-~e-,spring '~:;'~~~tr grazin_gseason. Om ~~.. :.,---,,-each yew. U-ne: errors~ :mean. 1" - -squared means_(~§Mrfgr. e~Chpasture during YaIUee across alt y ars. \lertlcatJ)ats ==:~ <standard ��187 Colorado Division- of Wildlife Wildlife Research Report July 1990 JOB PROGRESS State of Project Work Colorado No. ~W_-~1~5~3~-~R~ Plan No. __~2~ Job No. Period Author: REPORT 15 Covered: July _ Mammals _ Deer Investigations 1 Research Compensatory Effects Mule Deer Population of Harvest in a 1, 1989 - June 30, 1990 R. M. Bartmann Personnel: T. A. Abbott, H. E. Burdick, L. H. Carpenter, K. M. Chociej, B. L. Dupire, J. H. Ellengerger, D. J. Freddy, J. P. Gray, R. Harthan, E. K. Jones, J. D. Madison, J. E. Morris, R. E. Thomas, C. L. Teter, G. C. White, and numerous others from the Colorado Division of Wildlife and Colorado State University. ABSTRACT Eighty-four fawns and 49 adult female mule deer were radio collared on the control and treatment units of the Ridge study area. Preliminary estimates of over-winter fawn survival for 1989-90 were 0.667 (SE 0.096) and 0.583 (SE 0.082) on the control and treatment units, respectively. Adult survival was 0.905 (SE 0.064) and 0.667 (SE 0.091) on the same respective units. All adult mortalities except 1 were hunting related. Sixty deer were checked during the 3 regular seasons: 22 bucks, 36 does, and 2 fawns. Twenty-_one percent of the does were yearlings and 15% were aged as ~8 years old. The harvest estimate for the antlerless late season in December 1989 was 451 de~r. Twenty-eight percent of the deer recorded at check stations were fawns. Of the does, 10% wereyeCirlings and 37% were aged as ;::8 years old, about re";erse of the composition for the regular seasons. Estimates of p~pulation size-from aerial line transects were 1,227 (95% CI 746 - 1,708) and 1,420 (95% CI 1,173 1,667) on the control and treatment units, respectively. Fawn:doe ratios on the same respective units were 63.2:100 (95% CI 55.2 - 72.1) and 105.9:100 (95% CI 89.8 - 125.0). ��189 COMPENSATORY EFFECTS OF HARVEST IN A MULE DEER POPLATION Richard M. Bartmann P. N. OBJECTIVES 1. Increase the winter survival rate of mule deer fawns by lowering total deer density to reduce competition for forage during winter. 2. Increase the harvest rate of deer through increased productivity of adult does and decreased natural mortality of fawns resulting from closer alignment of population size with carrying capacity. 3. Evaluate deer harvest rates and population response on a DAD basis resulting from bucks-only hunting and from buck hunting with additional antlerless permits designed for annual removal of 20% of the adult female population. SEGMENT OBJECTIVES 1. To reduce the winter popUlation of mule deer on the Ridge treatment unit to a density <40/km2 and maintain that density for at least 3 years. 2. To estimate units. winter survival rates of fawns on control 3. To estimate annual survival rates of adult 4. To estimate annual survival rates of adult males. 5. To estimate productivity 6. To estimate harvest treatment units. 7. To estimate 8. To estimate age structure of adult females on the treatment unit condition of yearling females on control and treatment units. 9. To estimate age structure of adult males males on control and treatment units. rates condition females. of deer on control of bucks, does, of fawns on control METHODS and treatment and treatment units. and fawns on control and treatment and condition and units. and of yearling AND MATERIALS Deer Trapping Mule deer were captured with dropnets on 12 sites 13 sites on the treatment unit of the Ridge study on the control unit and area during November �190 1989·. Fawns and -adu Lt; females were radio collared and released to estimate over-winter and annual survival rates, respectively (White et al. 1987). Adult males were not radio collared. Experience last year revealed it is not possible to achieve a reasonable sample size and the extra effort to monitor them detracts from monitoring fawns and does. All transmitters contained a mortality mode set with a 3-4-hour delay. Male fawn collars were a drop-off type so they could be retrieved after -8 months and reused. Female fawn collars were expandable so survivors could continue to be monitored as adults. Adult female collars were of fixed size and remained permanently attached. In addition, all fawns and yearling adults, whether collared or not, were tagged in both ears to identify them as known-age animals to help refine aging techniques. All deer were weighed (kg) and total body length (cm) and left hind foot length (cm) measured (White et al. 1987). Antler measurements taken on bucks included circumference (mm) 2.S cm above the burr, main beam length (cm), and number of points and brow tines ~2.S-cm long. During the middle of January, February, and March, all radio-collared deer were located by triangulation to detect permanent movement between the 2 study units. Survival Radio-collared fawns were monitored for survival -S days/week beginning immediately after trapping until they migrated in late April (White et al. 1987). From then until IS June, they were monitored from a fixedwing aircraft approximately every 2 weeks. Adult females were monitored once weekly throughout the winter and monthly through the summer. All radio-collared deer were monitored daily during the regular and late hunting seasons. Each mortality signal was checked as soon as possible to determine cause of death, using criteria described by (White et al. 1987), or to retrieve a drop-off collar. Harvest Check stations were found inefficient during the 3 regular fall deer hunting seasons. Instead, visits were made to hunting camps or hunters were contacted in the field to obtain data for deer killed on the 2 study units. Each deer was weighed (kg) if the carcass was intact except for normal field dressing and had been dead <3 days. The same antler measurements described for live bucks were also taken. Each deer was field aged by tooth replacement and wear if permission was obtained to slit the jaw, although yearlings could still be identified without doing this. The 2 middle incisors were also taken from animals field aged as ~2 years for aging with the dental cementum technique (Erickson and Seliger 1969). If a known-age deer was killed, effort was made to collect the lower jaw. A late season for antlerless deer was held on the treatment unit 1-31 December 1989 to begin reducing the population. There was a concern with hunter crowding because of the small size of the hunt area (-28 km2) and �191 the large number of-deer to be removed. to take 2 deer on 1 license. Therefore, hunters were allowed For ease of description, the hunt area was expanded to include -6 km to the west of the treatment unit and a l-km band along the south side of the Ridge road was excluded. Hunt area boundaries were the powerline road on the east, the Ridge road on the south, Piceance Creek road on the west and the White River on the north. All boundaries except the river were signed at -1/2-km intervals. In addition, signs indicating direction and distance to the hunt area were placed at strategic locations along access roads. Each successful applicant was mailed a packet with a brochure describing the background and goals of the study and other information about camping, access, weather, etc.. A map was also enclosed along with a survey/tooth mailer to get harvest data and deer teeth from hunters not contacted at a check station. Hunters could either mail them or deposit them in collection boxes placed around the area. A check station was operated daily during the late season from 8AM to 6PM at the Little Hills headquarters. A temporary station was operated on weekends near the mouth of Hay Gulch. Information taken for each deer was the same as during the regular season. To encourage hunters to stop at a check station or return their survey/tooth mailers, a souvenir patch designed for the late season was given to all that did so. No harvest estimate was possible for the regular seasons. Instead, the number of deer checked in the field was used as the minimum number of deer removed. An estimate of total harvest for the late season was taken from the random survey conducted by the Division's Limited License Group. This survey also provided estimates of the number of people that did not hunt, that were unsuccessful, that killed 1 deer, and that killed 2 deer. Check station data were used to estimate the fawn sex ratio and age composition of the harvest. Final age assignments were based on all available data with jaw aging as the default for small or unreconcilab1e differences between techniques. Population Size An aerial line transect survey was flown in early January after the late season to estimate size of deer populations on the 2 study units. The transects were established in 1985 and had been flown every winter since then. Twenty-five transects were oriented north and south and systematically spaced at 0.4 km across both study units. There were 10 transects on the control unit, 12 on the treatment unit, and 3 transects crossed both units. These latter 3 transects were split where they crossed unit boundaries and the segments considered separate transects for their respective units. Lengths of transects ranged from 1.5 - 5.6 km and averaged 4.0 km. �192 Line transects were flown by 2 obervers and a pilot in a Bell Soloy helicopter. The survey was flown again the next day, in the opposite direction to the first flight, to increase the sample size of deer groups. Observer calibration and counting methods and analysis procedures were as given by White et al. (1989). Sex and Age Ratios Aerial sex and age classification were made on the 2 study units between the 2 line transect surveys. Classifications were made along the same lines used for line transects except that deer groups within 0.2 km on either side of the flight line were classified to achieve complete coverage. Buck:doe and fawn:doe ratio estimates were based on groups rather than individuals to improve precision. RESULTS Deer Trapping Eighty-four fawns and 49 adult females were radio collared on the control and treatment units from 13-30 November 1989 (Table 1). The last 4 female fawns captured received drop-off collars. Table 1. Number of mule deer trapped and radio and treatment units, 13-30 November 1989. Unit Control Treatment Radio collared collared on the control Adult Fawn Male Female Yes No 19 21 Yes No 18 3 Male Female 21 3 26 3 28 18 Body Size Measurements.--Based on 3 measures of body size, male fawns averaged larger than females on their respective units (Table 2). Also, male and female fawns and adult females on the control unit were larger than their counterparts on the treatment unit. There were not enough yearling and adult males and yearling females to make similar comparisons. No significance tests were performed. Movements.--No permanent movements of deer between the control and treatment units was observed. Seven deer, 2 from the control unit and 5 from the treatment unit, were each located 1 or 2 times on the opposite unit, but all were also located at least once on their original units. The 7 deer were captured on 3 trapsites located 0.5-2 km from the boundary between units. �193 Table 2. Body size measurements of mule deer captured with dropnets on the control and treatment units, November 1989. Unit Age Control Fawn Fawn 19 21 34.1 3l.4 0.42 0.37 131. 6 130.5 0.56 0.52 42.2 4l.4 0.32 0.33 2 2 48.5 46.0 l.63 l.79 151. 8 148.4 2.02 l.06 46.7 47.9 0.59 l. 23 2 19 73.5 67.7 2.88 0.52 167.9 168.6 2.32 0.52 50.7 48.1 0.38 0.24 21 26 3l. 5 29.9 0.41 0.34 127.0 126.3 0.51 0.45 4l. 3 40.3 0.23 0.24 1 7 60.8 53.3 1.17 168.5 l58.7a l. 36 50.0 46.7 0.33 1 39 93.4 65.0 0.39 196.0 165.9 0.42 5l.0 47.8 0.18 M M M F Yrlg M F Adult M F a n = Left hind foot length {cm) x SE M F Treatment Total body length {cm) x SE n F Adult {kg) SE Sex F Yrlg Weight x 6. Survival The previous high over-winter fawn survival was 0.520 (SE 0.071) on the treatment unit in 1985-86. The 1989-90 winter was extremely mild and this rate was surpassed on both units in 1989-90 (Table 3). These high rates occurred even with hunting mortality occurring for the first time since survival monitoring began on the Ridge in 1982-83. Table 3. Fate and preliminary survival estimates of radio-collared mule deer on control and treatment units from time of trapping in November 1989 to 15 June 1990. Age n Control Fawn Adult 40 21 Treatment Fawn Adult 44 28 Unit Hunting related Undeter. 3 2 1 3 1 6 5 9 3 Starve Accid. Trap related 2 Still alive Sa SE( S) 14 16 19 0.667 0.905 0.096 0.064 8 21 18 0.583 0.667 0.082 0.091 Collar drop-off a Trap-related mortalities and pre-mature collar drop-offs excluded from calculations of survival rates. are There was a problem with pre-mature collar drop-offs on male fawns and the 4 female fawns fitted with this type of collar. The release mechanism, latex tubing, was the same as used last year when no similar problems were encountered. This year, there were 22 pre-mature dropoffs, 64% of them with fawns from the control unit. The last fawn mortality occurred on 17 April 1990. If the assumption is made that all �194 fawns with collars dropping off after that date lived survival rates increase to 0.758 (SE 0.075) and 0.643 control and treatment units, respectively. to 15 June, (SE 0.074) on the Adult female survival to 15 June 1990 on the control unit was slightly above the previous 6-year average of 0.874 for the entire Ridge area. However, this could still change as adult survival is measured to 1 December. In contrast, survival on the treatment unit was already below the lowest rate recorded on the Ridge (0.764, SE 0.065, in 1986-87)and was due to hunting, the sole mortality cause, during the late season Harvest Sixty deer killed on and around the 2 study units were checked during the 3 regular hunting seasons (Table 4). One, 21, and 38 deer were checked during the 1st, 2nd, and 3rd seasons, respectively. Twenty-two of the 60 were bucks, 36 were does, and 2 were fawns. All deer except 1 were killed on the North Ridge, but not necessarily on the 2 study units. The exception was an eartagged buck killed on the ridge south of the Little Hills headquarters. Since the regular season harvest cannot be estimated, 60 is the minimum number assumed killed. Table 4. Mule deer checked on and around the control and treatment units during 3 regular hunting seasons and a late season in December, 1989. Season Regular 1st 2nd 3rd Control unit Buck Doe Fawn Treatment unit Buck Doe Fawn 1 1 7 8 4 146 Late a Antlers antlerless. 5 were <5-inches long and were 1 Not recorded Buck Doe Fawn 2 18 7 5 1 57 legal under the definition of The harvest estimate for the late season was 451. A breakdown of survey results shows 21.7% of the 375 license holders did not hunt, 10.0% were unsuccessful, 16.7% killed 1 deer, and 51.7% killed 2 deer. thus, slightly more than 500 deer were killed during all seasons, but this does not include any adjustment for wounding loss or illegal kill. Two radiocollared deer from the control unit, a fawn and a doe, were killed during the late season, but it is not known which unit they were on at the time. Two yearling bucks were killed, but their antlers were <5-inches long and they qualified as antlerless deer. Yearlings comprised 50% of the bucks checked during the 3 regular seasons (Table 5). Of the does, 21% were yearlings and 15% were estimated as ~8 years old. During the late season, 28% of the deer checked were fawns. Ten percent of the does were yearlings and 37% were aged as ~8 years old; reverse of the composition during the regular seasons. The hypothesis of constant age ratios across seasons was rejected (f = 0.050) and implies 1 �195 or both of these ratios do not reliably estimate the true population structure. Because of the intensity of hunting and the favorable snow conditions during the late season, age ratios for this season were assumed closer to truth. Table 5. treatment Season Regular Late a Estimated ages of mule deer checked on or near the control units during the regular and late hunting seasons, 1989. Sex Male Female 2 Male Female 29 28 Antlers were <5-inches of ant1er1ess. A e 4 5 6 7 ~8 3 1 5 1 2 2 5 13 21 7 9 54 1 2 3 11 7 4 6 3 3 2 9 17 Fawn and 2a 15 long and so were We compared age ratios derived from jaw aging and dental cementum when both were available for the same deer. Yearlings were excluded as incisors were usually not collected from j aw- aged deer and there were no corresponding jaw ages for mai1in teeth. The 2 age distributions in Fig. 1 were independent (f = 0.007). Compared to jaw aging, dental cementum placed a higher percentage of animals into younger age classes (2-4 years) and fewer into older age classes (~8 years) •... :z UJ (,) :: 1 JAW AGE the definition DENTAL CEWENTUW AGE 30 a: 20 UJ Q.. legal under i ._----------------- 10 AGE Fig. 1. Age composition of the doe harvest on the control and treatment units during all 1989 seasons as indicated by jaw aging and dental cementum. During the late season, most deer were killed early in the month and on weekends (Fig. 2). Opening day was on a Friday and helped spread the opening weekend pressure over a 3-day period. Fig. deer unit late marks 2. Distribution of the harvest on the treatment during the December 1989 season. The heavy tick indicate weekends. ""_, '"_, -'"' "" •.... '" X I:> 1 0 '" DAY �196 There was a significant difference in field-dressed weights of does between the regular and late seasons (f = 0.044), ages (f < 0.001), and the season x age interaction (f = 0.026). Yearling females killed during the late season were smaller than those killed during the regular seasons. Weights of mature females were nearly the same, but were confounded by the different age compositions between seasons. Population Size Population estimates from aerial line transects were 1,420 (95% CI 1,173 - 1,667) on the treatment unit and 1,227 (95% CI 746 - 1,708) on the control unit. The survey was made immediately after the late season and, therefore, reflects harvest removals from the treatment unit. For an unknown reason, the estimate on the control unit is much lower than the 1,800 - 2,00 deer estimated the past few years. We were unable to refly these transects to see whether or not this might have been a sampling artifact. Sex and Age Ratios Buck:doe ratios on the control and treatment units were 9.8:100 and 6.7:100, respectively. Both were lower than the 12.4:100 estimated for the entire Piceance Basin (Northwest Region, unpubl. data), but all confidence intervals overlapped. Fawn:doe ratios on the control and treatment units were 63.2:100 (95% CI 55.2 - 72.1) and 105.9:100 (95% CI 89.8 - 125.0), respectively. The ratio on the control unit is similar to the estimate for the entire Piceance Basin (65.7:100, 95% CI 61.3 - 70.3) (Northwest Region, unpubl. data), but both were lower than the ratio on the treatment unit. The reason for the high ratio on the treatment unit is unknown. The differential harvest of does and fawns would have increased the ratio slightly above that on the control, but not to this extent. LITERATURE CITED Erickson, J. A., and W. G. Seliger. 1969. Efficient sectioning of incisors for estimating ages of mule deer. J. Wildl. Manage. 33:384388. White, G. C., R. M. Bartmann, L. H. Carpenter, and R. A. Garrott. Evaluation of aerial line transects for estimating mule deer densities. J. Wildl. Manage. 53:625-635. _____ , R. A. Garrott, R. M. Bartmann, L. H. Carpenter, and A. W. Alldredge. 1987. Survival of mule deer in northwest Colorado. Wildl. Manage. 51:582-589. Prepared by 1989. J. � https://cpw.cvlcollections.org/files/original/f2cec1f683159cb7831b16a5b25d465e.pdf 9d2e1faa1745ec56d41d025b4c576640 PDF Text Text I Colorado Division of Wildlife Wildlife Research Report September 1990 JOB PROGRESS REPORT State of Colorado Project 01-03-212 Work Plan 1__ Job Migratory 17 Job Title: Habitat use by wintering Period Covered: Authors: Game Bird Research mallards along the Front Range of Colorado 1 April 1989 through 31 March 1990 James K. Ringelman and Michael R. Szymczak Personnel: R. Falise, Colorado and Cattle Company State University; L. Roberts, Front Range Land ABSTRACT No additional field work was conducted this segment. Project objectives can be attained with existing data on wetlands classification and availability, weather, habitat selection by radio-marked mallards, bird movements and behavior,. and effects of hunter disturbance. Detailed data summaries of the 1986-87, 1987-88, and 1988-89 field seasons are presented in October 1988 and October 1989 annual reports. These data will be analyzed in greater detail for inclusion in technical journal publications to be completed next segment. ��3 Colorado Division of Wildlife Wildlife Research Report September 1990 JOB PROGRESS REPORT State of Colorado Project 01-03-212 Work Plan 1__ : Job Migratory 18 Job Title: Winter survival and reproductive Period Covered: Authors: Game Bird Research success of female mallards 01 April 1989 through 31 March 1990 James K. Ringelman and Michael R. Szymczak Personnel: D. Anderson, Colorado Cooperative Fish and Wildlife Researc~ Unit; C. Jeske, Colorado State University; R. Hopper, J. Ringelman, M. Szymczak, Colorado Division of Wildlife; M. Nail, R. Schnaderbeck, U.S. Fish and Wildlife Service. ABSTRACT Authorization to bait-trap mallards on the Monte Vista National Wildlife Refuge was denied, consequently no new field work was conducted this segment. However, comprehensive analyses were completed on three years of field data. Logistic regression analysis was used to investigate relationships between body condition of mallards and winter through spring survival rates. Potential effects of radio-marking were also evaluated. Body mass and condition indices were compared to other mallard populations, among age and sex classes of mallards in the San Luis Valley, and between years for individuals captured during successive field seasons. Relative recovery rates of wing-banded mallards were examined in relation to body condition, age, and sex of the bird. Wing remains were used to partition mortality attributable to starvation, avian cholera, and lead poisoning. Basal energetic requirements were deduced from oxygen respirometry experiments. "Energy acqui~ition was quantified using field-feeding trials coupled with data on metabolizable energy of common foods. Trace element analysis of down feathers was performed using feathers of known origin, but did not prove effective for distinguishing between migrant birds and those that were resident in the San Luis Valley during winter. Graduate Research Assistant Clint Jeske is preparing a dissertation that will serve as the final report on this project. The dissertation will be finalized in December, 1990, and reported next segment. ��5 Colorado Division of Wildlife Wildlife Research Report September 1990 JOB PROGRESS REPORT State of Colorado Project 01-03-212 Work Plan 1__ : Job Job Title: Evaluation Period Covered: Authors: Migratory Game Bird Research 19 of Nesting Habitat Management for Ducks 01 April 1989 through 31 March 1990 David W. Gilbert. James K. Ringelman. Personnel: D. Anderson, Colorado Cooperative Fish and Wildlife Research Unit; J. Ringelman, M. Szymczak, Colorado Division of Wildlife; D. Gilbert, . Colorado State University; S. Brock, S. Burlinger, M. Nail, R. Schnaderbeck, U.S. Fish and Wildlife Service. Abstract Personnel on the Monte Vista National Wildlife Refuge (MVNWR) have used transects to collect information on nesting ducks every year since 1964 (except 1977). Data on species composition and nesting success of 4,074 duck nests located over 24 years provide a basis to evaluate the benefits of habitat management practices including grazing, water application, burning and predator control. Work performed this segment focused on identifying and obtaining information on management practices, and preliminary exploration of duck nesting data. Mallards composed 54% of the nesting duck population on the MVNWR, followed in abundance by teal species and pintail. Units 3, 9, and 18 produced more ducks than other areas, but units 9 and 18 increased in relative importance when nests were expressed on a density basis. Most nest failures were caused by predators (21.7%) or desertion (12.3%). Baltic rush was the vegetation most commonly associated with nest sites; whereas few nests were found in sedge, spikerush, or cattail. Because detection rates of nests decreased with increasing distance from the center line of the transect, line transect theory is being used to derive detection functions that will enable unbiased estimates of nest numbers. Two different cattle grazing practices were employed on 57 pastures during 1964-88. Hay was also cut on 14.4% of the refuge beginning in 1964, but was phased out by 1976. Predator populations 'and control efforts were conducted throughout the period, but few quantitative data are available. Records of water application are more complete, but because of the varied water sources and methods of transport and application, data will have to be treated on a refuge-wide basis. Prescribed burning was initiated in 1981, with 12 burns conducted on -5,200 acres during the 1980's. Aerial photographs of the MVNWR have been obtained for 1969, 1978, and 1985. Vegetative associations will be delineated from these photographs and digitized in preparation for analyses of vegetation change and relationships to duck nesting biology. ��7 EVALUATION OF NESTING HABITAT MANAGEMENT FOR DUCKS David W. Gil bert James K. Ringelman P. N. OBJECTIVES 1. Relate nesting duck species composition, density to habitat management practices. nest success rate, and nest 2. Assess changes in wetland and upland vegetation between 1962 and 1985 by contrasting digitized habitat information derived from aerial photographs. 3. Determine nesting habitat preferences of duck species by comparing of nesting habitat with relative habitat availability. usage SEGMENT OBJECTIVES 1. Conduct an extensive literature review on the effects of grazing, burning, herbicides, predator control, early water application, and vegetative characteristics on nesting waterfowl. 2. Verify the correctness and completeness of nesting transect data already entered on computer. Enter data into spreadsheet software, then conduct preliminary analyses on species composition, nest success rates, nest density, etc. by year and wetland unit. 3. Locate records on grazing, burning, and if possible water application and predator control for individual wetland units on the Monte Vista National Wildlife Refuge (MVNWR). Computerize these data for entry as independent variables for categorical data analyses. 4. Obtain aerial photographs (appx. 1:6,000 scale) of the MVNWR. vegetative associations, and verify accuracy of classifications truth surveys. Determine the area of vegetative types. 5. Complete annual Delineate by ground report. STUDY AREA Nesting data used in this study originate from the MVNWR, located 6 miles south of the town of Monte Vista (e1ev. 7,600 ft.) in the San Luis Valley (SLV) of south-central Colorado. The SLV is best described as a cool desert, receiving less than 12 in. of precipitation annually. Therefore the agricultural communities largely rely, as does the refuge, on the irrigation water supply. The vegetation on the refuge is predominantly baltic rush (Juncus balticus), greasewood (Sarcobatus vermiculatis), and rabbitbrush (Chrysothamnus spp.). Szymczak (1986) provides additional descriptions of the MVNWR. �8 The surrounding mountains (San Juan and Sangre de Christo ranges) collect snow and subsequently supply water to the SLV via the Rio Grande River and a network of irrigation canals. Underground aquifers are also an important supply of water for the SLV and the MVNWR. The refuge began to use these water sources to produce wetlands in the early 1950's. Today a network of pumps, ditches, and dikes keeps 22 of 24 (total 14,189 ac.) individual nesting management units flooded for waterfowl use (units 12 and 13 are never surveyed for nesting waterfowl and will not be mentioned in reporting). The MVNWR offers a wide variety of nesting habitat. Generally, the western side of the refuge supports an upland greasewood/rabbitbrush association interspersed with numerous impoundments. A band of agricultural fields exist along a north-south line with the refuge headquarters (Fig. 1). Grasslands and wetlands continue eastward until near the eastern edge of the refuge, where greasewood/rabbitbrush again prevails. INTRODUCTION TO METHODS Beginning in 1964, an annual waterfowl production the MVNWR. This survey was to provide the following: 1. 2. 3. survey was initiated on A representative, statistically adequate sample of the duck hatch as a basis to project duck production. Information on the location, cover types used, and success of nesting waterfowl throughout the refuge for use in evaluation of ecological succession of vegetation and related habitat management practices. A consistent record of long-term population trends of other wildlife species important to the refuge. The survey design resulted from pre-sampling in 1961-63. It was calculated that 640 acres of transect would be required to estimate production within 10%-15% with a 95% level of confidence (MVNWR survey instructions). Originally (1964-68) 142 "strip" transects were used to estimate the parameters of interest. At 16.5 feet wide (8.25 ft./side), 5.5% of the refuge was sampled (640 acres of 11,570 available for nesting, or 320.5 miles of transect). No correction for missed nests was used. Nesting surveys were scheduled for mid-May, mid-June and July. June surveys were used to verify the fate of nests initially located in May, as well as to locate any new nests. The July survey was included to determine fate of nests found in June. Nesting parameters were collected at the time of the initial survey and included date, unit number, transect number, species, incubation stage, number of eggs (also number of parasitic eggs) and vegetative cover type in which the nest was located. Fate was determined and causes for failure were recorded on subsequent surveys. Other information was collected sporadically, such as nests of species other than ducks, distance to standing water, overhead cover, and distance to the centerline of the transect. These data were valuable but rarely complete or consistent. Beginning in 1969 the number of transects were halved due to manpower limitations. In order to not substantially decrease the area sampled, transect width was increased to 24 feet (12 ft./side) and all nests located were included for use in density estimates. The area covered then was 4.0% of total nesting habitat. The 1969 Annual Narrative Report indicated that the new method would be evaluated (i.e. estimation of the percent of nests �:x: 0 I-0:: z •• w (.!). =:J L1.. W 0:: L1.. W •..... _J 0 _J :::= ...... _J e:( z 0 •..... I-- z e:( e:( I-I/} •..... >w I-Z 0 :::i: I/} I-- •.....• Z =:J I-- z w =:: w (.!) e:( z e:( ::::: LI.. .,... 9 �10 actually found out to the distance of 12 ft.) at a future date. No evaluation of the 24 foot transect been found nor has there been any change in estimation procedures. Production was calculated from the number of nests found in the strip, mUltiplied by a factor to compensate for fractional sampling. Data were then corrected for species in the breeding population, species composition of the nests found, percent hatching success, and brood size for each species (see Appendix 1 for weighting calculations). However, no correction for missed nests at the increased transect width was used. Data used in sections of this preliminary report, such as species composition and success, were derived only from the nests actually found and recorded. When appropriate detection function curves are derived from data of the recorded distance from centerline, a correction factor will be used to accurately determine nest density by correcting for nests missed. At present, the approximate nest densities were calculated using actual data collected. No use was made of the annual production figures derived by MVNWR, which take into account brood size and breeding pair composition. METHODS Because this report contains analysis of data not derived from a controlled experiment, it is important to point out what records will be used and the source of information. Effort has gone into the collection of appropriate records as opposed to the traditional collection of new field data, as is standard in most research. Records Search Nesting Data. - Nesting and associated attribute data were entered on computer directly from actual field forms on file at MVNWR. Often the original field forms were recopied to summary sheets so most comments (for example, distance to centerline of the transect for nest relocation) were eliminated. Nesting information comes from the following nests: 2,180 222 571 104 354 90 553 Mallard nests, 53.5% Gadwall nests, 5.4% 14.0% Teal nests, Shoveler nests, 2.6% Pintail nests, 8.7% Redhead nests, 2.2% Unknown nests, 13.6% This totals 4,074 nests for the period 1964-88 (excluding 1977 when data was not collected); 1989-90 will be analyzed at a later time. One canvasback, one ring-necked duck and nine ruddy ducks were recorded over the period but were not included in the tabulation. Fourteen green-winged teal were reported but were grouped with all "teal", as teal species were not easily distinguished during nesting surveys. Management Data. - Records of management practices, (grazing, water application, burning, and predator control), elevated platform photography, vegetative cover mapping, and changes in transect methods were derived form Annual Narrative Reports kept at the MVNWR office in Alamosa. Water records �11 used to determine wet/dry cycles were obtained from gauging station records at Del Norte, Colorado (Colorado Water Resources, 1964-88). This station records flows prior to major diversions and is a good indicator of general SLV water conditions during a given year. SLV breeding pair information was provided by the Division of Wildlife (M. Szymczak, pers. comm.) These data were obtained to allow for detection of years where nesting densities may have been related to the overall SLV duck population as well as refuge conditions. Similarly, North American breeding pair survey records are included for additional comparisons (USFWS 1989). Ve~etation. - Original study plans called for comparative analysis of elevated platform photographs of unit 6 taken during the late 1960's (Fig. 1), with new photographs to be taken at the same location in 1990. A file was found that explicitly outlined the procedure and some locations of photo points, but no photographs were found. A pilot project to develop a standardized system to map vegetative cover types on the MVNWR preceeded the elevated platform photo work in the 1960's. Information found pertaining to this proposed cover mapping is similar to that described by Graham (1945). These files contained procedures outlining how to map the refuge. Preliminary work using this system was conducted in units 6 and 19 prior to wetland development by student trainee Leslie Beaty. This initial survey provides a 1962 "snapshot" of those units. Correspondence associated with those early files emphasizes the importance of future evaluations of cover conditions compared with baseline data collected in 1962. However, no further evaluations were located and it is doubtful that follow-up mapping occurred. Aerial Photographs. - A new methodology was employed to fulfill the objectives of the original photo/cover work. A search for a series of refuge-wide aerial photographs that could provide information on temporal change in refuge vegetation was undertaken. Suitable photographs were located for 1969, 1978, and 1985. These photographs will be ground truthed and features and cover attribute information will be digitized into the Geographic Information System (GIS) ARC/INFO. This methodology will allow accurate area determinations of each cover type by unit, as well as areas of ponds, dike roads, parking areas, fields, wetlands, and uplands. Such data are essential for accurate determination of nesting densities used for comparison between different management regimes. Initial cover mapping and polygon delineation will be performed using the 1985 photography. Later, plotter-produced mylar overlays will be superimposed over 1969 and 1978 imagery and polygons will be re-drawn were necessary to identify vegetation changes. These changes will then be digitized into separate databases to enable quantification of temporal change in refuge vegetation. Transect Data Correction For the purpose of this project, nest projection totals must be corrected for missed nests during the nest search procedure. Because all nests were not found at a transect width of 16 ft. (Anderson and Pospahala 1969), projection of total nests would be low if the number found were not adjusted. This error is multiplied when distance sampled was increased to 24 feet. Data on nest distance from centerline (measurements were available �12 1969-74, 1986, and 1987) will be used in program "Transect" (Burnham et. al. 1980) to develop a model that will fit the curve of falling detectability. A correction value will be determined from the appropriate model. Detectability differences between species and years will be evaluated and appropriate corrections will be made to account for changes in data collection over time. RESULTS Nesting Data The species composition for the 24-year period 1964-88 (1977 omitted) depicts relative increases in gadwall (Anas strepera) and teal species, and decreases in northern pintail (~ acuta) and "unknown" ducks (Fig. 2). The percent composition made up of mallards (Anas platyrhynchos) has remained relatively steady, except for a decrease in the late 1970's (Fig. 3). These data represent all nests found regardless of changes in effort among years. The highest duck nesting densities were found in units 3, 9, and 18, all units located directly east of the Empire Canal (Fig. 1). These units produced more ducks than eastern or western units (Fig. 4). Enright (1971), reported a two ft. drop in elevation in unit 18 from west to east. This compares to a 40 ft. drop in unit 19. Other units, such as 6 and 15, have moderate drops (approximately 20 ft.) but have extensive wetland development and are moderately productive. Shallow standing water is known for production of lush vegetation, a possible reason for the large number of nests in units with slight elevation changes. When data were corrected for the length of each transect (Fig. 5) or area of each unit (Fig. 6), units 1, 2, 6, and 8 increased in relative importance. Units 9 and 18 had the highest nest densities on the MVNWR. These data will be further refined to better reflect true nesting densities as detection function correction values are derived. Data may also change slightly when acreages are calculated from the GIS database. It should be noted that unit 24 was not searched until 1981; therefore caution must be exercised when comparing unit 24 to the other units. According to nests found, redheads (Aythya americana) showed a preference for units 3, 6, 7, 9, and 13, gadwall for units 3 and 6, and teal for units 3 and 18 (Fig. 7). Most nests were located in baltic rush, the dominant herbaceous vegetation on the MVNWR (Table 1), although greasewood often provided shrub cover in the vicinity of the nest when they were located on hummocks above the high water line. Few nests were found in sedge, spikerush, or cattail. Most nest failures were caused by predators or were deserted for unknown reasons (Table 2). The overall success rate of 4,074 nests, uncorrected for exposure, was 52.8%. Records Search Grazing. - Records of cattle grazing on the refuge have been located being computerized. Two grazing strategies were employed. The first for grazing after the nesting season (mostly during fall) on virtually entire refuge annually. Later, there was a reduction in total grazing and are called the and an �Z 100 o - 100 U5 o a.. 80 80 ~ o o 60 60 J- 40 40 20 20 r-t0_"r-r-l J- Z W () a: W a.. o o mallard li!l!ili!ll!:illl unknown 1°:°::::::1 teal 1::,::::1 pintail '85 '80 '75 '70 '65 1»1 gadwall ~ shoveler D redhead Fig. 2. Species composition of duck nests found on the Monte Vista National Wildlife Refuge, 1964-88. Data for 1977 not included. Composition is uncorrected for missed nests. I-' W �14 ~r-------------------------------------~~ Malard 110 . r---------------------------------------, 14 .............•...•.......•.... 12 10 ..••••..•.•••••............... 10 8 ~ 14 12 - •••................ e -...... ..- ................•..... . 4 Yerl Yerl ,-------------------------------------~~ Teal Rect>ead 8 30 .....••....••....•....................•••••••......•. 20 ....•.•••••••••.........•••...•.......•••.•...•...•••••• •••••.•.....•.••••••.••••••••••• ..........•••••.....................................................•...•....••••••....•......... 30 " 3 . . . . 10 Yerl ~,-------------------------------------~~ 20 ...•.........••.....•.••.•.........•••.••.........•.....••.....•••••........•••••.•.......••.... 20 15 ...........................••••................................ 15 10 ........•........... . Shoveler 5 •. -----.-- ...•. --.- 4 .•....••••••••••••••••••. 3 - .••.••.•. ------. ... - .• - .. ------.-.- •. --.-.- . .........•••..........••........•.•••.....•••••••••••• 10 2 . Yest: 30,--------------------------------------30 Urknown ..........•..•. ~ ... _............. •..•.•.............•..... . ...•.•....••.•....•.....• -............. 20 15 ..........................••••..•........ 15 10 .••••••.................................. 10 Fig. 3. Temporal change in species composition for principal nesting ducks on the Monte Vista National Wildlife Refuge, 1964-88. .•. ---- .. -...... .-. 5 �15 1 2 3 4 5 6 7 8 9 10 11 14 15 16 17 18 19 20 21 22 23 24 Unit Number Fig. 4. Total duck nests found by unit, 1964 through 1988, uncorrected for differences in effort. Data from 1977 not included. 70 eo 50 ~ c: Q) 40 ::::I c:r e 30 U. 20 10 1 2 3 4 5 6 7 8 9 10 11 14 15 16 17 18 19 20 21 22 23 24 Unit Number Fig. 5. Total nests found by unit, 1964-88, corrected by the distance of each transect. Data from 1977 not included. 0.8 ~ c Q) o.e ::::I c:r •.. Q) U. 0.' 0.2 1 2 3 4 5 6 7 8 9 10 11 14 15 16 17 18 19 20 21 22 23 24 Unit Number Fig. 6. Total nests found by unit, 1964-88, corrected for the area of each unit. Data for 1977 not included. �I-' o- Mallard D Gadwall Teal ~ Pintail ~ Shoveler ~ Redhead 30 +oJ C Q) o 20 ~ Q) D... 10 o I 1lt111l1JIlIdi 11m-.I 1 2 3 4 5 IIUl 11m•• n "HI 6 7 8 9 IIlil IIIN 11m "Ib! "IJ "11 "rN "" 10 11 14 15 16 17 18 IIIdI 19 20 lin "'I 21 22 -b uu 23 24 Unit Number Fig. 7. Species composition of nests found by unit, 1964-88 (1977 excluded). , �17 every-third-year rotation plan was implemented. The rotation system was intended to remove most of the dense residual cover every third year (Mel Nail, MVNWR, pers. comm.) A total of 57 pastures were grazed during 1964-88, but not all were completely grazed and total ADM's differed considerably among years (Fig. 8). The relation of grazing treatment to nesting densities will be evaluated in the future. Table 1. Vegetation associated with 4,074 nests located National Wildlife Refuge, Colorado, 1964-88. Dominant plant species Number Sedge (Carex spp. ) on the Monte Vista Percent of total 55 l.4 Saltgrass 130 3.2 Spike rush 61 l.5 146 3.6 2,761 67.8 619 15.2 78 l.9 3,850 94.6 Grasses Baltic rush Greasewood Cattail Totals Table 2. Colorado, Sources of nest failure on the Monte Vista National during 1964-88. N = 4,074 nests. Cause of failure Number Wildlife Percent of total Deserted 502 12.3 Predator/Eaten 886 2l. 7 Flooded 126 3.0 Unknown 480 11.7 1,994 48.7 To t a.I s" Totals differ from the summation more than one cause recorded. a of individual causes because Refuge, some nests had �18 .....................................................................................................•............................... 6,000 5,000 ~ :J « co +-' r--0 4,000 3,000 2,000 1,000 0 , 70 '65 '75 '85 '80 Year Fig. 8. Total cow-calf units (AUM) grazed on the Monte Vista National Wildlife Refuge, 1964-89. 2,000 "0 1,500 Q) ~ I * = no records Q) OJ co .._ 1,000 Q) o « 500 o .................................................•.•.. * '65 , 70 * ,75 Year Fig. 9. Total hay produced on the Monte Vista National Wildlife Refuge, 1964-76 ·········· ·.. 1 �19 Haying. - At onset of this project we were unaware that haying ever occurred on the MVNWR. Haying can have detrimental effects on nesting success depending upon chronology of flood irrigation and hay cutting. In 1964 hay was cut on 14.4% of the refuge (1,665 acres). Subsequently the acreage was gradually reduced and finally eliminated (Fig. 9). Haying was restricted to units 4, 7, 14, 20, 22 and 23 (Bill McDermith, MVNWR pers. comm.). We could not locate records of the amount and acreage hayed by unit or information on whether a particular unit was hayed in a given year. Units in which haying was know to occur will be treated differently when appropriate in future analyses. Predator control. - Predator control data has been assembled but have not been analyzed. From the annual narrative reports it is apparent that control varied widely, as did predator populations. Poisons were used in the 1960's, and were reportedly effective. However, no quantitative data were available. Trapping effort is also missing for most years. Water application. - The application of water is of utmost importance to waterfowl on the MVNWR. Anderson (1967), Pospahala (1969), and Robinson (1971) demonstrated the relationship between early water application, vegetation characteristics and nesting densities on the MVNWR. Schroeder (1973) demonstrated> 2-fold increases in densities of aquatic invertebrates in areas with early water application. Summer water is equally important for brood rearing. Since the work of the above mentioned authors, early water application has been a major objective at the refuge. (Bill McDermith MVNWR, pers. comm.). Total water use on the MVNWR was stable during 1964-73, decreased during 1974-77, then increased markedly thereafter (Fig. 10). The increase reflected increased wetland habitat developed during the 1980's. Unfortunately, potential benefits of water distribution are easier to document than the actual water distribution over a large area over time. Available water records indicate the actual amount of pumped and canal water available by year. Total water in the Rio Grande at Del Norte, Colorado is a general indicator of SLV water conditions (Fig. 11). However, there are a myriad of ways water can be applied to different areas of the refuge through a complex network of ditches. Winds, winter precipitation, winter ice buildup, and timing of the spring thaw all play a role in how successful the refuge is at water application. Further complicating this picture are the> 200 artesian wells located throughout the refuge that vary in size, depth, and pressure, and flow unmetered at different amounts in different years depending on local water table conditions. It will therefore be impossible to determine the exact timing or amount of water applied on a per unit basis. Therefore, subsequent analyses will examine refuge-wide duck recruitment parameters in relation to overall water application. Relationships may exist among SLV water conditions, MVNWR water conditions, SLV breeding pair numbers and MVNWR nest densities. For instance, in a dry year, a larger proportion of the breeding ducks available in the SLV may be attracted to MVNWR, where water is artificially applied than would be the case in a wet year when SLV wetlands are full. Yearly changes in numbers of breeding pairs on the MVNWR generally reflected Valley-wide changes for all �20 35,000 1- 30,000 "'0 c . 25,000 0 o Q) en -;:,. 20,000 Q) Q) LL o 15,000 ..0 :::J o 10,000 5,000 o , 65 '70 , 80 '75 '85 Year Fig. 10. Total water used on the Monte Vista National Wildlife Refuge from all sources, 1964-89. 600,000 500,000 "'0 c 0 o Q) 400,000 en -;:,. Q) Q) LL U ..0 :::J o 300,000 200,000 100,000 0 '65 '70 '75 , 80 '85 Year Fig. 11. Rio Grande River water totals as an index of San Luis Valley water conditions. �21 species combined (Fig. 12) and mallards (Fig. 13). Mallards comprised a l~wer percent of the total SLV breeding population according to aerial surveys (z 34.3%) than nests found on MVNWR (K = 53.5%) over time. There was a low correlation between the number of SLV mallards and the number of North American mallards, total ducks, and total ducks other than mallards (r-square = 0.149, 0.187 and 0.099 respectively). The SLV is apparently very important to nesting ducks and the MVNWR is becoming an increasingly important portion of the SLV. Habitat changes Valley-wide have reduced the number of breeding pairs off refuge, yet refuge numbers appear relatively stable. Further analyses will focus only on changes within the MVNWR in relation to habitat conditions and management. Prescribed burning. - Prescribed burning (ditches excepted) was not used at the MVNWR as a habitat manipulation procedure until 1981, according to records located to date (Table 3). The 1980 Annual Narrative discusses initiation of training procedures, acquisition of fire control equipment, and beginning of a fire use strategy. Up to this time, the only references to burning were passages in annual reports that stated: "no prescribed burns occurred in calendar year 19 ,nor do we feel the need for such management". Burn~ng Table 3. Prescribed Refuge, Colorado. burns conducted on the Monte Vista National Wildlife Size (acres) Year Unites) 1982 4 250 1983 9 unknown 1983 19 180 1984 14/15 560 1984 17 450 1984 3/4 600 1984 18 400 1986 unknown 320 1988 unknown 25 1989 6 640 1989 8/17 880 1989 9/10 900 �22 MVNWR 1,;,;,;,:-:-;;·;·1 30,000 - SLY .............................................. = _ ··············· · .._ o, .._ ··· ·· ·..·..1 CJ) "tlj Q) ..Q 20,000 ········ * no ·••········..······ count · ··..·····..·······1 E ::::J Z 10,000 '65 '70 , 80 '75 '85 Year Fig. 12. Duck breeding pair estimates for the San Luis Valley and Monte Vista National Wildlife Refuge, 1964-89. I 15,000 I MVNWR - SLY ...................••.......................................................................................................................................................................... .._ CJ) "tlj n, .._ Q) * no 10,000 ..Q E ::::J Z 5,000 o count •...••...........•..................................................................................................................... ~LULULilLU~~-=~.u~~~UL~~~~~~u.~u_ '65 '70 __ '75 '80 , 85 Year Fig. 13. Mallard breeding pair estimates for the San Luis Vallay and the Monte Vista National Wildlife Refuge, 1964-89. �23 200 ~---------------------------------- 150 ~ ............................................................................................................ ·······································1 'Q) ...Q E ::::J 100 Z 50 o o 2 4 6 8 10 12 Distance from Center (ft) Fig. 14. Detectability function of 1,465 duck nests found on the Monte Vista National Wildlife Refuge. �24 began at neighboring Alamosa NWR for control of common reed (Phragmities australis) and was increasingly used thereafter at both refuges into the 1980's. Typically, burning followed the third year of grazing and was described to completely clean a given unit of dense residual cover. Eleven prescribed burns have been conducted on the MVNWR since 1982 (Table 3.) Sampling Correction Measurements of the distance from the transect line were obtained for 1,465 nests. Neither duck species or personnel changes (i.e., year-to-year variation) contributed to variation in the detectability function. Visual inspection of the nest detection data (Fig. 14) suggests a nearly linear decrease in the detectability of nests as a function of distance. However, no particular model has yet been selected as the "best fit" model to use in detection function equations necessary to correct for missed nests. DISCUSSION The species composition and nesting densities of ducks on the MVNWR has fluctuated dramatically since 1964. Variation of comparable magnitude was also apparent in the number of nests found over time within individual management units. Detailed analyses of these relationships will have to wait until sampling corrections and vegetation analysis is performed. On an individual unit basis, rarely are there enough nests to consistently detect statistical differences in densities within years (typically N ~ 10 for any unit within a year). The actual number of nests found was also dependent on weather conditions, the size of the breeding population, the species composition of the breeding population, and the availability of water in the SLV and on the MVNWR. Thus, to determine cause and effect relationships between nesting and management practices it will be necessary to pool data from units with common treatments. These analyses will be the primary focus of work to be conducted next segment. Literature Anderson, D. R. and habitat. Cited 1967. Effects of water manipulation on waterfowl M.S. Thesis, Colorado State Univ., Ft. Collins. Anderson, D. R., R. S. Pospahala. studies of immotile objects. production 60pp. 1970. Correction of bias in belt transect J. Wildl. Manage. 34:141-146. Burnham, K. P., D. R. Anderson and J. L. Laake. 1980. Estimation of density from line transect sampling of biological populations. Wildl. Monogr. 72:1-202. Colorado Water Resources. 1964-1987. Colorado stream flow information. �25 Enright, C. A. 1971. An analysis of mallard nesting habitat on the Monte Vista National Wildlife Refuge. M.S. Thesis, Colorado State Univ., Fort Collins. l13pp. Graham, S. A. 1945. Ecological Manage. 3:182-190. classification of cover types. J. Wildl. Monte Vista National Wildlife Refuge. 1964-1989. Annual Narrative Reports and miscellaneous files. Alamosa National Wildlife Refuge Files. Alamosa, Colo. Pospahala, R. S. 1969. Waterfowl production and vegetative water. M.S. Thesis, Colorado State Univ., Ft. Collins. response 96pp. to early Robinson, G. W. production. 1971. Vegetation and physical factors influencing waterfowl M.S. Thesis, Colorado State Univ., Fort Collins. l48pp. Schroder, L. J. production. 1973. Effects of invertebrate utilization on waterfowl M.S. Thesis, Colorado State Univ., Ft. Collins. 44pp. Szymczak, M. R. 1986. Characteristics of duck populations in the intermountain parks of Colorado. Colorado Div. Wildl., Div. Rep. 6. 13pp. u.s. Fish and Wildlife Service and Canadian Wildlife of waterfowl and fall flight forecast. 39pp. Service. 1989. Status U.S.D.A. Soil Conservation Service. 1980. Common Colorado Range Plants. Soil Conservation Service., Denver Co. 55pp. Prepared by: ~) David W. Gil bert Graduate Research Assistant C!fo-.2<~ James K. Ringelman Wildlife Researcher C �26 Append; x 1 Forms outlining estimation of production, MVNWR -:.--nTw::;~'!;:r;:,-___, riW"J~~o~~~1J No. ne3t. Frail. Spa COIlP_ Known flea tIS I forll !P..e:ks __ .... !_c;-,V_ .J-.n. :;eoi~bt <Col. e_~ 3 .. Z No. Bre.dins Duck~ (C) __ ~~,,'r.'::l .\~?t;:_--ll~ Sp. COQP. 1n .~ . St'_ W.is~t Coail_ <Col. 6 _1~_;;'_.__!,. 1)_ ·J.l~ht Sp.Ccop. 11'\ see , (Gol. ~ (~) (Col. 9 ..:.£.2.!. •.2l!-_) ___. .!'~l._ -. -- ~}~~- nn • ----- r~ntall 1-, Gad""3-11 I - - I ShoVf!ll~t" ; - I Clnn.T~al ~:.:t. Te~l f -- - .- !\~dh~a.d i !lU~~T ' -(Total) -I---, Iii _L_ ~-,,!!,wn ~i- 1 - I-- Coot feria t I TCT"L - -'-t--. r---~-- I· --._.----r---·· --t--+-·_-j--_·r-I I ...~.- ..-tl . ~ _L__L__l __~L_ D-6. (10) Sp. Coap. in tlos. Specie.:t _ ( 12) (11) Jatching ne , Ne e t e Hatched on Tr"an8~c Success ta 1n ~ (Col. 9 (for_"~e) for" x~t~o~t.~l~~~-'~ __ (££!::l!) +-~Col. 2 fluddy '1---1-1--1 --L--+---t---r--+-~Un:<now~n ~-=.l=~ ± L- ..--·~1:~_~~_L_~J__ I _ ..~'."'" =+===l====i====1==-= AL I TO:r =c.~ot,------,-_-"-- .. __ -_I 4= ~ = -I .~ �27 Colorado Division of Wildlife Wildlife Research Report September 1990 JOB PROGRESS REPORT State of Colorado Project 01-03-212 Work Plan 1__ : Job Job Title: Development in Colorado Period Covered: Authors: Migratory Game Bird Research 20 and Evaluation of Moist-soil Management Techniques 01 April 1989 through 31 March 1990 James K. Ringelman and Michael R. Szymczak Personnel: R. Brown, R. Hopper, S. Hoover, T. Ostertag, J. Ringelman, M. Szymczak - Colorado Division of Wildlife; L. Roberts - Front Range Land and Cattle Company; C. Crosby - Big Meadow Farm, Inc. ABSTRACT Technical and popular literature was reviewed for information on moistsoil management techniques applicable to Colorado. Wildlife researchers in Missouri and Texas responded to letters of inquiry and provided details of ongoing moist-soil studies in those states. Personnel in Kansas and adjacent states were consulted during a waterfowl habitat management workshop hosted by the State of Kansas. Progress on the "expert system" computer software for moist-soil management was reviewed with personnel of the U.S. Fish and Wildlife Service. Based on this information, eight criteria were developed for screening potential sites to construct experimental moist-soil impoundments. Four candidate sites were considered, and field surveys were conducted at each site. One site, the Wellington Wildlife Management Area northeast of Fort Collins, was deemed acceptable for impoundment .construction. Barring unforeseen complications, impoundmeni: ':designand c'onst ruc t i.on will begin at Wellington ih fall 1990, with a sprihg 1991 completion date~ High soil permeability, timing of water availability, amount of water available, and cost of water are potential limitations to moist-soil management in Colorado. Most soils near eastern plains riparian areas are sand or sandy-loam, which make it difficult to maintain water and moist-soil conditions. Ditchwater, the most cost-effective source of water for impoundments, is generally unavailable until mid-May. Conventional moist-soil techniques would require that water remain impounded over winter "or be applied in March or April in preparation for May drawdown. However, these and other limitations are common throughout eastern Colorado, therefore any suitable moist-soil management techniques must work within these cons t ra lnt s if such management is to be widely adopted. Work next segment will evaluate the feasibility of moist-soil management given limitations on water availability. ��29 Development and Evaluation of Moist-soil Management Techniques in Colorado James K. Ringelman Michael R. Szymczak P. N. OBJECTIVES 1. Formulate a list of desirable moist-soil plants likely to benefit waterfowl in Colorado, as well as a list of potential problem species techniques for their management. and 2. Develop prescriptions for moist-soil management in eastern Colorado, detailing time of water application, duration of inundation, and water quality and substrate characteristics necessary for establishment of selected plant species and control of nuisance species. 3. Evaluate waterfowl responses to moist-soil units, including rate of food acqu~s~t~on, plant species preference, differential usage by waterf~wl species, and seasonal use patterns. SEGMENT OBJECTIVES 1. Review literature on moist-soil management practices, and consult with experts to gain insight into management techniques applicable to Colorado. Determine the status of the prototype expert system for moist-soil management being developed by the U.S. Fish and Wildlife Service, and evaluate the feasibility of applying this system to moist-soil units in Colorado. 2. Design moist-soil management experiments based on information obtained in approach 1, including plant species objectives and number of replicates/experimental treatments needed to reliably define management prescriptions. 3. Define essential criteria for experimental moist-soil management units, including location, soil characteristics, water source and quality, and minimal size of each unit. Consult with CDOW personnel and private individuals to locate potential sites. Work with engineering and property management personnel to develop guidelines and specifications for construction of experimental moist-soil units. METHODS Information Review Technical journals and popular literature were reviewed for information on moist-soil management techniques. Correspondence was sent to wildlife researchers active in the area of moist-soil management. During 13-16 February 1990, J. Ringelman traveled to a waterfowl management workshop hosted by the State of Kansas and consulted with experts on moist-soil management. Personnel at the Office of Information Transfer and the National Ecology �30 Research Center (both offices of the U.S. Fish and Wildlife Service) were consulted for information on moist-soil management techniques. Site Selection Criteria for suitable moist-soil experimental wetlands were developed based on data gathered during the information review. Correspondence outlining study objectives was forwarded to District Wildlife Managers and Area Biologists employed by the Colorado Division of Wildlife. In addition, private landowners with suitable sites were contacted and field visits were made to several sites. RESULTS Information Review One of the most efficient wetland management techniques available is the collection of practices known as moist-soil management: the management of plant species that grow on exposed mud flats (Fredrickson and Taylor 198~). Seeds of these species regularly survive flooding and can exist for years in areas subjected to prolonged drying (Van der Valk and Davis 1978). Under favorable conditions, usually at or slightly below field capacity, rapid germination allows re-establishment of these plants (Van der Valk 1981). Production of vegetation in naturally flooded or impounded wetlands is related to the timing of water removal in the spring. Annual changes in weather and seed availability, and succession in the wetland plant community, affect the resultant diversity and growth of plants, as does the time it takes to drain and re-flood an area (Fredrickson and Taylor 1982). Vegetation density and composition is dramatically affected by the degree of soil drying that follows water removal (Kirby 1988). Waterfowl food production is enhanced and maintained through proper timing of water removal and careful control of water levels throughout the year. The foods of greatest value are the seeds of native aquatic and semiaquatic plants and the invertebrates that associate with these plants (Fredrickson and Reid 1986), but vegetative growth and tubers are also consumed (Kirby 1988). Invertebrates provide protein used by female ducks during egg laying (Swanson et al. 1979, Drobney 1982), food for ducklings during their growth stage (Krapu and Swanson 1977), and nutritional supplements for waterfowl during fall and winter (Heitmeyer 1988). Moist-soil techniques allow management schemes targeted at important species by manipulating food availability to coincide with migration and breeding phenology, and providing preferred vegetative foods. Shorebirds are especially responsive to moist-soil management practices (Rundle and Fredrickson 1981). Wetlands are dynamic systems, and therefore cannot be continuously maintained at a desired high level of productivity. Periodic low levels of productivity must be accepted as part of the cost of maintaining a wetland of overall high quality. The effects on the waterfowl community are minimized by providing a complex of wetlands, managed to provide continuously available, high quality habitat. Initial development of moist-soil impoundments is expensive if heavy equipment is required for dike construction and elaborate water control structures are needed. A reliable source of water, precise control of water �31 levels, and the ability to completely drawdown an impoundment are all vital characteristics of moist-soil units (Fredrickson and Taylor 1982). Once constructed, moist-soil impoundments are often less expensive to manage than row crops, and have several advantages over row crops that are traditionally cultivated for waterfowl. Nutritional qualities of natural seeds are more balanced than those of cereal grains, and are often preferred by waterfowl. The total energy in moist-soil foods often is as high or higher than that in corn, milo, or soybeans (Fredrickson and Taylor 1982). Row crops, by virtue of their large seed size and physical structure, are suitable only for a select group of the larger waterfowl: geese, mallard (Anas platyrhynchos), and Northern pintail (A. acuta). These crops also do not provide shelter for waterfowl, another desirable trait of moist-soil plants. Unlike row crops, which may fail or have reduced yields as a result of unfavorable weather, weather conditions have a lesser effect on a naturally occurring flora which includes species that reproduce well under a variety of conditions. In addition to this plant diversity, aquatic invertebrates, reptiles, and amphibians flourish in moist-soil impoundments. This variety of organisms, while desirable in itself, attracts a wide range of larger wildlife species to an impoundment (Burgess 1969). Over 80% more species are found in moist-soil units than on adjacent row crops (Fredrickson and Taylor 1982). The distribution of plant and animal species differs with latitude. Consequently, wetland management techniques that work well in some areas may not work as well or at all in other regions. Colorado has environmental conditions that differ from those regions of the country where moist-soil management is traditionally practiced. The growing season is relatively short, precipitation is low, and evapotranspiration is high. Moreover, water is scarce, expensive, and seasonal abundance varies considerably. Traditional water management practices often run counter to regimes beneficial to moistsoil plants. For example, most irrigation reservoirs are filled during September-November, remain full during winter, then are drained rapidly in June-August to meet irrigation demands (Ringelman et al. 1989). Moist-soil impoundments generally benefit from low pool levels during winter, a gradual filling during March-April, high water levels through June, then an abrupt lowering of water levels in early July to allow seed germination (Nelson et al. 1978). Despite these apparent handicaps, moist-soil management has been successfully adapted for use in arid environments (Kirby 1988). At Bosque del Apache National Wildlife Refuge in New Mexico, techniques have been developed to encourage desirable waterfowl foods including alkali bulrush (Scirpus acutus), horned pondweed (Zannichellia palustris), millets (Echinocholoa spp.), sago pondweed (Potamogeton pectinatus), spike rush (Eliocharis spp.), and smartweeds (Polygonun spp.), while controlling undesirable plants such as cottonwoods (Populus spp.), willows (Salix spp.), saltcedar (Tamarix chinensis), Russian olive (Elaeagnus angustifolia), phragmites (Phragmites communis), cocklebur (Xanthium strumarium), and cattail (Typha spp.). Several of these species are present on Colorado's eastern plains, and it is reasonable to expect that many of the techniques applicable in New Mexico would succeed in Colorado. Ongoing research is focusing on substrate cultivation techniques as a technique to enhance germination rates of moist-soil plants and provide a more desirable moist-soil plant community (L. H. Fredrickson, Gaylord Memorial Laboratory, pers. comm.). These investigations of "advanced" management �32 methods are being conducted in Missouri, where moist-soil techniques have been practiced for a decade and plant responses in relation to drawdown date and moisture regimes are well documented. In Texas, investigators are initiating research on managing playa lakes for moist-soil species (L. M. Smith, Texas Tech University, pers. comm.). Their research is intended to develop management prescriptions similar to those identified in this study. Wildlife managers in Kansas and elsewhere in the Mississippi alluvial valley have developed moist-soil waterfowl impoundments using technology adapted from the rice cultivation industry. Levee plows are used to confine water in small, shallow impoundments. Such levees can be built and removed quickly in response to water availability and waterfowl management objectives. Lightweight, portable water control structures are used to precisely regulate water levels inside impoundments. The timing and duration of drawdowns, as well as control of undesirable plant species, are complex considerations in moist-soil management. The complexity is increased if water delivery systems do not allow independent flooding and dewatering of impoundments. To aid the manager in decision making, the U.S. Fish and Wildlife Service is developing an "expert computer system" that prescribes management actions based on responses to a series of questions (D. Hamilton, National Ecology Research Center, pers. comm.). The system currently being developed has applicability to Mississippi Valley habitats, but basic relationships may be adapted to conditions in Colorado. The expert system is schedules for completion by January, 1991. Criteria for Site Selection Sites for experimental moist-soil management units in Colorado are most limited by four factors: (1) soil permeability, (2) the timing of water availability, (3) the amount of water available, and (4) the cost of the water. Many state wildlife areas and private duck clubs are located in the South Platte River Valley. Soil types are primarily sand or sandy-loam, underlain with occasional and often non-contiguous clay layers. Consequently, seepage rates are high, and continual water application might be necessary to maintain moist-soil conditions during plant germination and growth. Rivers and water storage reservoirs are the sources of irrigation ditchwater in eastern Colorado. Often, such water is unavailable until several agricultural users place a "call" for irrigation water in mid-May. Unfortunately, this is the period when water should be removed from an impoundment to encourage many desirable moist-soil plants. Thus, either an early source of water must be used to fill impoundments during April, or impoundments must be able to hold water through fall and winter into spring. During most of the year, water is not free anywhere in Colorado. Water users must own shares of water (which entitle them to a portion of the total water available from an irrigation company) or must be willing to pay pumping costs of well water. In either case, the quantity of water must be sufficient to fill impoundments to the required depths while compensating for seepage and evaporative loss. The cost of ditch water ($4 -$20 / 1,000 mJ) is usually lower than water pumped from wells ($20 - $31 / 1,000 m3), but under some circumstances both may be cost-prohibitive for moist-soil impoundments. Moreover, Colorado water law states that water must be put to beneficial use, and therefore water rights are adjudicated for specific purposes. Most ditch �33 and well water is designated for agricultural applied to moist-soil impoundments. Experimental Criteria were developed for screening The area must be able to accommodate in size. 2. Each moist-soil unit must have flooding and de-watering. Elevation legally be Area Specifications 1. 3. use, and cannot change along potential 6 impoundments, independent the longest moist-soil water dimension study sites: each at least control 2 acres structures of the impoundment for should be < I ft. 4. Water sources develop. and delivery 5. Water 6. Water rights research. 7. The area must be under government control or, if privately owned, the landowner(s) must be willing to enter into a 5-year agreement to allow moist-soil research and agree to finance the cost of capital construction as needed. 8. Soil surveys must verify that seepage rates are sufficiently is feasible to develop wetlands on the site. must be available must be in place in sufficient must not preclude Based on these criteria, suitability. Candidate systems several quantity the use of water candidate or cost-effective at the appropriate for moist-soil areas were evaluated to times. management low that it for Sites Brush Prairie Ponds State Wildlife Area. - This newly-acquired state wildlife area is slated for major wetland developments as the first Ducks Unlimited MARSH (tlatching aid to Restore ~tate's Habitats) project in Colorado. The area consists of undulating sand hills with "pothole" type wetlands in the lower basins. Smartweeds and other moist-soil plants are present in some wetlands. Water is owned by the City of Brush, 2 miles to the north, and is applied via a series of ditches that transport water from the nearby South Platte River. The municipal water supply for Brush is drawn from deep wells located near the wildlife area. Surface water is applied to recharge the aquifer, therefore newly-designed wetlands are designed to have high seepage rates. This site was judged unsuitable for experimental moist-soil units. The volume and amount of ditchwater available for flooding impoundments is dependent upon river flows and calls on the ditch, which make the water source unpredictable. Additionally, seepage rates will average 1 foot/day for new �34 impoundments. Thus, shallow moist-soil overnight if deprived of water. impoundments would literally dry up Chestnut Slough (Front Range Land and Cattle Company). - This area provides a complex of warmwater and coldwater wetlands used primarily for waterfowl hunting. The area is < 600 acres in size, and contains little relief in the area potentially available for moist-soil impoundments. Water for impoundments would need to be supplied from wells. Because of the small area available for impoundment construction, high cost of well water, and legal constraints on capital construction (levees, control structures, etc.) on private land, this area was judged unsuitable for experimental moist-soil units. Big Meadow Farm. Inc. - Another private property, this hunting club had several desirable qualities that made it a good prospect for moist-soil units. Half of its 470 acres was set aside as a waterfowl refuge. Water was available from several sources, and a ditch delivery system was in place. A clay layer underlaid most of the flat bottomland, which bordered on the South Platte River. Several thousand waterfowl use the property during fall and winter. Club members were eager to cooperate on the project and were willing to make arrangements to help finance capital construction. Preliminary engineering surveys in fall 1989 indicated that elevation gradients were unfavorable for constructing moist-soil units. Ditches were in need of repair and cleaning, and water, although plentiful most of the year, was scarce during March and April when it was most needed for moist-soil work. This area was dropped from consideration as an experimental site because of these and other considerations. Wellington State Wildlife Area. - This wildlife area is located within 30 minutes of the Fort Collins Research Center. A full-time property technician oversees development and management of waterfowl impoundments and associated upland nesting habitat. The area has abundant water supplied by the Cowan Ditch, which flows from about May 10 through 20 September during average years. Several acres of flat ground located northeast of the property headquarters have been designated for future waterfowl impoundments. The property technician and associated management personnel are eager to cooperate on an experimental moist-soil venture. Heavy equipment and personnel are available to construct levees and install water control structures. A turnout and lateral ditch already exist in the area designated for potential development. The only known limitation to this site is the timing of ditchwater availability in spring. This appears to be a common limitation throughout eastern Colorado, and it is now believed that any practical moist-soil management system must be operable within the constraint of ditchwater availability. Consequently, this site has been selected for construction of experimental moist-soil management units beginning in late fall and winter 1990, barring any unforeseen complications. Target date for completion of the units and initial moist-soil work is spring 1991. �35 DISCUSSION Highly permeable soils and the timing of ditchwater availability are major constraints to moist-soil management in Colorado. Any moist-soil management system must overcome these obstacles before it can be widely applied in the eastern regions of the state. Experimental moist-soil units will be constructed at the Wellington Wildlife Management Area to evaluate the practicality of moist-soil management under these constraints and to derive management prescriptions to achieve desired plant responses. LITERATURE CITED Burgess, H. H. 1969. Habitat management on a mid-continent refuge. J. Wildl. Manage. 33:843-847. Drobney, R. D. adaptations waterfowl 1982. Body weight and composition changes and for breeding in wood ducks. Condor 84:300-305. Fredrickson, L. H., and F. A. Reid. 1986. Wetland and riparian habitats:' A nongame management overview. Pages 59-96 in J. B. Hale, L. B. Best, and R. L. Clawson eds., Management of nongame wildlife in the midwest: a developing art. The North Central Section of the Wildlife Society. 1982. Management of seasonally Fredrickson, L. H., and T. S. Taylor. U.S. Dep. Inter., Fish and flooded impoundments for wildlife. Wi1dl. Servo Resour. Pub. 148. 27pp. Heitmeyer, M. E. 1988. Protein costs of the prebasic molt of female mallards. Condor 90:263-266. Kirby, R. E. 1988. Highlights of the moist-soil management workshop. Fish and Wildlife Service, Office of Information Transfer, Fort Collins, Colorado. 57pp. U.S. Krapu, G. L., and G. A. Swanson. 1977. Foods of juvenile, brood hen, and post-breeding pintai1s in North Dakota. Condor 79:504-507. Ringelman, J. K., W. R. Eddleman, and H. W. Miller. 1989. High plains reservoirs and sloughs. Pages in L. M. Smith, R. L. Pederson, and R. M. Kaminski, eds. Habitat management for migrating and wintering waterfowl in North America. Texas Tech Press, Lubbock. Rundle, W. D., and L. H. Fredrickson. 1981. Managing seasonally flooded impoundments for migrant rails and shorebirds. Wildl. Soc. Bull. 9:80-87. Swanson, G. A., G. L. Krapu, and J. R. Serie. 1979. Foods of laying female dabbling ducks on the breeding grounds. Pages 47-57 in T. A. Bookhout, ed. Waterfowl and wetlands - an integrated review. The Wildlife Society, Washington, D. C. �36 Van der Va1k, A. G. 1981. Succession Ecology 62:688-696. in wetlands: a G1easonian approach. Van der Va1k, A. G., and C. B. Davis. 1981. The role of seed banks in the vegetation dynamics of prairie glacial marshes. Ecology 59:322-335. Prepared by: q...,. ~~ James K. Ringelman Wildlife Researcher C �37 Colorado Division of Wildlife Wildlife Research Report September 1990 JOB PROGRESS State of Colorado Project 01-03-212 Work Plan 10 Job Title: Cooperative Period Covered: Author: : Job REPORT Migratory Game Bird Research _1_ Management Programs 01 April 1989 through 31 March 1990 Michael R. Szymczak Personnel: James K. Ringelman Wildlife and Michael R. Szymczak, Colorado Division of ABSTRACT The statewide waterfowl management plan was completed and submitted for administrative approval. Recommendations for wetland habitat improvements on present holdings or proposed acquisitions were provided for Russell Lakes, Spinney Mountain Ranch, Brush Prairie Ponds, South Republican and Union Slough and Stagecoach Reservoir SWA's; for Hebron Ponds and Walden Reservoir (BLM); and for the Routt and Arapaho National Forests and Pawnee National Grasslands (USFS). An extensive st.udy of duck production was conducted in montane habitat study areas on the Rout-t; National Forest. At least a dozen educational presentations concerning duck recruitment in montane habitats or general w'aterfowl ecology were prepared· and given. Responsibiliti~s as Colorado's representative on Pacific Flyway Study Committees and Council were fulfilled. Methodology for conducting duck, Canada goose and sandhill crane production surveys were prescribed for some specific areas. ��39 Cooperative Migratory Bird Management Programs Michael R. Szymczak James K. Ringelman In 1988, the Colorado Division of Wildlife (CDOW) created the Migratory Game Bird Program Unit (MBPU) within the Terrestrial Wildlife Section. This administrative change combined all individuals having statewide responsibilities for research and management of migratory game birds. Members of the MBPU work in concert to improve migratory bird management in Colorado. This job was created to allow team members to participate in these management programs. P. N. OBJECTIVES 1. Participate in developing and implementing habitat-based waterfowl management plans on a statewide, habitat region, and project basis. 2. Advise state and federal land managers on beneficial habitat acqu~s~tions and/or developments and provide expertise in preparation of development and/or management plans. Advise private land managers in developing habitat management plans and assessing impacts on waterbird populations. 3. Present information on the principles of waterfowl management to workshop attendees, educational classes, and conservation organizations. 4. Participate levels. 5. Cooperate in developing surveys and techniques of migratory bird management programs. in migratory bird management meetings at the state and flyway that will assess the impact SEGMENT OBJECTIVES 1. Complete final draft on waterfowl habitat of statewide waterfowl region plans. 2. Provide biological expertise for wetland development programs on the Brush Prairie Ponds State Wildlife Area (SWA), Russell Lakes SWA, South Republican SWA, Hebron Ponds (BLM jurisdiction), Walden Reservoir (BLM jurisdiction), Routt National Forest (U.S. Forest Service jurisdiction, and other areas when requested. 3. Prepare and present when requested. 4. Compile appropriate population status information and represent Colorado at Pacific Flyway Technical Committee and Council meetings. Attend migratory bird management program meetings in Colorado when requested. informational programs management on migratory plan. Begin work bird'management �40 5. Provide surveys methodology for wetland when requested. habitat and migratory bird population RESULTS Waterfowl Management Plans Early drafts of the statewide waterfowl management plan were reviewed and corrections and changes made based on comments from CDOW personnel and outside reviewers. Tables and figures were improved and prepared for publication. The final draft of the statewide waterfowl management plan was submitted to the CDOW Director and the Colorado Wildlife Commission for approval. The plan was published as: Colo. Div. of Wildl. 1989. Colorado Statewide Waterfowl Management Plan 1989 -2003. Colo. Div. of Wildl., Terrestrial Wildl. Sect., Migr. Game Bird Prog. Unit. Ft. Collins, co. 98pp. The Russell Lakes SWA management plan, prepared by CDOW Southwest Region personnel, was reviewed and changes were recommended. This plan will be rewritten in a more detailed form following the accumulation of water rights data and the construction of contour maps. Proposed developments at the South Republican, Brush Prairie Ponds and Spinney Mountain, and Stagecoach Reservoir SWA's were recommended. Suggestions for wetland alterations have been included in the management plan for the South Republican SWA. Water flow as through the. Brush Prairie Ponds SWA was altered as a result of our recommendations. The South Park waterfowl management plan, including habitat alterations suggested for the Spinney Mountain SWA, is being developed by CDOW Southeast Region personnel. Proposed wetland developments on public lands at Hebron Ponds and Walden Reservoir (BLM) , the Pawnee National Grasslands (USFS) and on the Arapaho National Forest (USFS) in Middle Park were visited and comments made to the appropriate agencies. In addition, a proposal for aquatic vegetation control on Shadow Mountain Reservoir was reviewed in reference to possible effects on waterfowl populations. Construction of l8-Island Reservoir in the Hebron Pond complex was completed by the BLM and negotiations for a stable water supply continue. Wetland development sites north of Walden Reservoir were proposed in conjunction with the BLM. A delivery system that will enable additional water to be placed in Walden Reservoir was cooperatively financed and constructed. An agreement to use a portion of the CDOW water in Walden for additional wetland developments is being negotiated. Roosevelt National Forest personnel developed plans and a priority ranking for wetland enhancement on the Pawnee National Grassland. Proposals were submitted for funding and some were approved. An extensive, cooperative study of nesting waterfowl on a forested study site just south of Big Creek Lakes (Routt National Forest) was undertaken to identify factors limiting production on this site and to set protocol for future waterfowl research and management on Forest Service lands. Recommendations were developed for habitat manipulations to address those factors. Results of this cooperative study are presented as an appendix to this report. �41 Proposed Wetland Acquisitions A proposed addition to the Union Slough SWA was visited, and potential developments discussed. The addition to the Union Slough SWA has been included in acquisition plans of the CDOW Northeast Region. We served on a committee to develop a rating criteria for wetland acquisitions and development for the Northeast Region of the CDOW. These criteria have been approved for use by the Regional Manager. Population Survey Methodology Spring duck count surveys were planned for Russell Lakes and Spinney Mountain SWA's. Project and Southeast regional personnel will cooperate conducting surveys on Spinney Mountain SWA. Informational in Programs At the invitation of the State of Kansas, lectures were presented on current waterfowl research and management in Colorado. Formal presentations on waterfowl recruitment in montane habitats were presented to the national meeting of the Society of Wetland Scientists and the Colorado Chapter of The Wildlife Society's annual meeting. Other formal presentations were made to U.S. Fish and Wildlife Service personnel at the National Ecology Research Center, the Wildlife Management Shortcourse and Wildlife Biology Workshop at Colorado State University, and to U.S. Forest Service personnel at several locations throughout the region. Waterfowl Technical Committee and Council Meetings Colorado was represented at the July 1989 Pacific Flyway Study Committee and Council meetings and March 1990 Study Committee meeting. Waterfowl population status was reviewed in July and hunting season recommendations forwarded to the U. S. Fish and Wildlife Service's Regulation Committee. Populations of specific interest to Colorado whose status was reviewed in July were (1) breeding and wintering mallards inhabiting the Pacific Flyway portion of Colorado and (2) the Rocky Mountain Canada goose population. General information on Pacific Flyway migratory game bird populations was exchanged by committee members in March. Regulatory recommendations made to the Pacific Flyway Council included hunting season regulations for Rocky Mountain Greater Sandhill Cranes and Four-corners Band-tailed Pigeon populations. Population Survey Methodology Methods for conducting duck brood counts were outlined for the Russell Lakes SWA. A reconnaissance of the Spinney Mountain SWA was conducted in fall of 1989 and methods of measuring waterfowl production and defining limiting factors relayed to managers. After consulting historical survey information, a time schedule for duck breeding pair and brood surveys was recommended. Methods were outlined for conducting Canada goose production surveys on Walden and MacFarlane reservoirs and Lake John Annex in North Park during spring 1990 in order to document suspected poor productivity on Walden �42 Reservoir. All goose nests on the 3 areas will be visited, marked and mapped in early May just prior to hatch. The number of eggs in each nest will be recorded. Periodic brood counts will be conducted after hatch with brood size and age recorded. The nests will be revisited after all have hatched, and the fate of each nest will be recorded. "Nearest nesting neighbor" distances will also be recorded for all nests located on islands. Comments were made on the draft recovery plan for nesting Greater Sandhill Cranes in Colorado that was prepared by the CDOW Northwest Region. In addition, information on minimum viable populations, south-central Wyoming nesting populations and general behavior during chick rearing of greater sandhill cranes was obtained from a number of sources and conveyed to Northwest Region personnel. DISCUSSION Project personnel proved to be a useful resource in planning and evaluating waterfowl management and habitat enhancement programs in Colorado and educating land management agency personnel about the habitat requirements of waterfowl. We anticipate that with increased emphasis on habitat enhancement in Colorado as outlined in the statewide Waterfowl Management Plan that our services will be more in demand. Continued participation on Flyway committees ensures that Colorado will remain informed on migratory bird matters and have input in migratory bird hunting regulations. Prepared by: ?Y/,"J{!..IJ{? ~....e Michael R. Szymczak Wildlife Researcher C �43 APPENDIX A Report on the cooperative habitats investigation in the Routt Field of waterfowl National Forest, recruitment Colorado Personnel R. Langley, Colorado State University M. Willms, Colorado Division of Wildlife J. Ringelman, Colorado Division of Wildlife Cooperators J. Ficke, U.S. Forest Service, Steamboat Springs C. Neelan, U. S. Forest Service, Steamboat Springs S. Kozlowski, U.S. Forest Service, Walden C. Yancey, U.S. Forest Service, Walden G. Hetzel, U.S. Forest Service, Denver L. Mullen, U.S. Forest Service, Denver S. Porter, Colorado Division of Wildlife, Walden K. Snyder, Colorado Division of Wildlife, Walden M. Szymczak, Colorado Division of Wildlife, Fort Collins R. Hopper, Colorado Division of Wildlife, Fort Collins S. Steinert, Colorado Division of Wildlife, Fort Collins B. Neeley, The Nature Conservancy, Boulder in montane �44 WATERFOWL ABUNDANCE, PRODUCTION, AND HABITAT ROUTT NATIONAL FOREST, COLORADO USE ON THE James K. Ringelman, Mark A. Willms, and Richard S. Langley Colorado Division of Wildlife, Ft. Collins, CO 80526 Abstract: We quantified abundance, habitat use, and production of waterfowl in a 9.6 km2 study area south of Big Creek Lakes on the Routt National Forest. In 1989, we enumerated 59 breeding pairs of ducks (6.1 pairs/km2) representing 6 species. Mallard (Anas platyrhynchos), ring-necked duck (Aythya collaris) and green-winged teal (A. creeca carolinenis) were the most common species. Pair and brood use were strongly correlated with pond size, with larger wetlands receiving greater than expected use. Pond origin was a secondary factor affecting wetland use by waterfowl. Based on the high pair use, species diversity, general lack of re-pairing, and high proportion of pairs observed with broods, such factors as pond numbers, upland nesting cover availability, nest success, and early season invertebrate numbers appear not to be limiting duck production. However, suitable nest cavities may be in short supply for bufflehead (Bucephala albeola). Mean brood size at fledging was lower than expected (4.1 young/brood), suggesting that duckling survival is the factor most limiting duck recruitment. The most likely causes of poor duckling survival were the general absence of flooded emergent cover after 1 July, and heavy growth of cowlily (Nuphar polysepalum) in late summer, which impeded brood movements and caused separation of ducklings. Management actions recommended to improve duckling survival include hard-stem bulrush (Scirpus acutus) introduction and herbicide spraying to create travel lanes in ponds with dense cowlily. Bufflehead nest boxes are also recommended to improve nest use and success for this species. Recent declines in North American duck populations have prompted coordinated action by state and federal natural resource agencies. Under the umbrella of the North American Waterfowl Management Plan (NAIJMP), the U.S. Forest Service (USFS) has initiated a 5-year, $18 million program to survey and improve waterfowl habitat on USFS lands. This program, called "Taking Wing", addresses the needs of breeding waterfowl through habitat preservation and development. Significant waterfowl production occurs in mountainous areas of Colorado (Colorado Division of Wildlife 1989). Reliable water sources create a wetland community that is less subject to annual perturbations than grassland habitats. Stable habitat is particularly important during times of widespread drought on the prairie breeding grounds, such has occurred in recent years. Despite the importance of mountain habitat for waterfowl, information on breeding duck densities and habitat use is scarce. Previous studies are largely restricted to those by Rutherford and Hayes (1976) for the upper Rio Grande drainage and Frary (1954) for the White River Plateau in Colorado. Over half of the ducks produced in these studies were mallards, a species of primary concern in the NAIJMP because of recent population declines. Habitat development techniques proposed for the "Taking Wing" program include (1) wetland vegetation management and construction of new wetlands, (2) upland nesting cover enhancement and creation of secure nesting habitat in the form of islands, nest structures, or predator-proof enclosures, and (3) �45 Ko,,'tt tl<\tiWQI Fcce.s+ j I I K'P\ I I I .I I Co lo.-o..elo Ar,'J. MeSas �W I-I-- « _J . a. z u.. o ~ * cr: o u, * z * 46 ~ 8: -z _... o- ~ . 0<) ..•.. \)"'0 J .Jtn 8~ 3 ~ V :t~«l ./ ./ / / d~ 0 ~ * .. .v. * �~ w W 0:: o * co o M N t'( ::)- aM '...., .,.. c:J ..., cf - 0 :l- ~~ D 0.:' 47 �48 ~ w w a: o WM en o o C!' ,~ .. " * * / I I , I ,I I J \ I ~ I ;' * ._..-_- * * �~ w w a: o W 0: LL « :c en M * * * ~ -:£. \ !J~ \ ~ t:.. "'0 11'1 <, 6.:s- <V ,... ~ 0 * 49 / I I\ \ _ ______.. /-\-/ \ J I I .•. c:1\ -t'\ I ,) \ I \ / I I \ I i I I �50 prov~s~on of additional permanent water areas and establishment of animal and vegetative foods. These techniques, which have been developed and tested primarily in prairie habitat, may attract and hold breeding pairs, increase nest success, and enhance brood survival, respectively. Unfortunately, which of these factors may limit waterfowl production in Rocky Mountain breeding habitat is unknown. Applying any management technique without first identifying the limiting factor is a waste of valuable resources. In order to determine which of the habitat management options might be most cost/effective in terms of increasing waterfowl production on National Forest lands, we decided to take a management experiment approach (Walters 1986). This paper describes the first phase of this project, that of setting up the experimental units, obtaining pre-treatment data, determining the factor(s) most limiting waterfowl production, and recommending specific management actions aimed at addressing these shortcomings. The second phase of this experiment would be to implement the management proposals on the designated treatment units, repeat the same data collection procedures for 12 years, and by comparing the results on the treatments and control units with the pre-treatment data, assess the actual effectiveness of the management actions. Our specific objectives were to (1) determine the species composition, abundance, and habitat use by breeding waterfowl pairs, (2) use the ratio of lone drakes to pairs as an indication of nesting chronology and nest loss/renesting activity, (3) measure duckling survival rates to fledging, and habitat use by brood-rearing hens, and (4) recommend management actions directed at factors limiting waterfowl production. STUDY AREA We investigated 186 wetland basins of either beaver or glacial origin within a 9.6 km2 section of the Routt National Forest just south of Big Creek Lakes, approximately 33 km northwest of Walden, Colorado (Fig 1). Elevation of the study area ranged from 2573-2774 m (8520-9100 ft). Dominant forest vegetation in the area consisted of lodgepole pine (Pinus contorta), Engelmann spruce (Picea engelmannii), subalpine fir (Abies lasiocarpa) and quaking aspen (Populus tremuloides). Riparian zones were dominated by willows (Salix spp.), with smaller amounts of water birch (Betula occidentalis) and mountain alder (Alnus incana). Common aquatic vegetation included cowlily, grassleaf pondweed (Potamogeton gramineus), fineleaf pondweed (E. filiformis), spiked watermilfoil (Myriophyllum spicatum), northern mannagrass (Glvceria borealis), and sedges (Carex vescaria and Carex utriculata). Less common aquatic plants included Richardson pondweed (E. richardsonii), common mares tail (Hippuris vulgaris), hemlock waterparsnip (Sium ~), yellow water buttercup (Ranunculus flabellaris), common arrowhead (Sagittaria latifolia), common spikerush (Eleocharis palustris), narrowleaf burreed (Sparganium angustifolium), water sedge (Carex aguatilis) and bluejoint reedgrass (Calamagrotis canadensis). All beaver ponds were located on or adjacent to either the North Fork of the North Platte (NFN Platte) or 3 of it's primary tributaries: Forester, Goose and Shafer Creeks. Boundaries partitioning the study area into 4 study units were established along their watershed divides (Figs. 2-5). Without prior knowledge of the study area, the NFN Platte and Goose Creek sites were designated as the treatment units and Forester and Shafer Creek as control �51 Table 1. Comparative attributes of the 4 study units National Forest, Colorado, 1989. Unit Size (k~) No. wetlands Beaver located in the Routt available Moraine Wetland density N. Fork N. Platte 2.00 66 9 37.5 Forester 2.56 22 21 16.8 2.38 39 5 18.5 2.67 1 21 8.2 9.61 128 56 19.1 Goose Creek Creek Shafer Creek Totals units. Although attempts were made to keep these units comparable, large differences in both the number and type of wetlands in each study block occurred (Table 1). Because of stream gradient differences, both the number and complexity of beaver ponds present along each of these 4 creeks varied. Thus the NFN Platte and Goose Creek, both low gradient streams, had the highest number and diversity of beaver ponds, while Shafer Creek, a high gradient stream, had the lowest. Forester Creek, with a high gradient headwater and a low gradient lower reach, was intermediate. Since the principal water source for these creeks was high mountain snowfields, water levels on all main-stern beaver ponds remained relatively stable throughout the breeding season. In contrast, beaver ponds located on secondary drainages lacking mountain water sources tended to be more unstable. Glacial moraine ponds were randomly scattered throughout the forested inter-creek areas. Hydrologically, these moraine ponds were isolated by thick ridges of glacial till. Since their water supplies are entirely dependent on local snow melt and summer thunderstorms, water levels gradually decline as the breeding season progresses. The long term stability of these ponds most closely resemble those in the prairie parklands. Most of the larger moraine ponds either contained active beaver or signs of recent activity. METHODS We conducted breeding pair surveys on all wetlands present in each of the 4 study units at 7 day intervals from 22 May to 7 July, 1989. Data recorded included species, number of pairs or lone individuals present, general activity (i.e. sitting, flying), wetland location, and time of day. We used quiet observation techniques to avoid flushing ducks and causing count duplications. For analysis of habitat selection, only pair data recorded between 26 May and 15 June were considered, since both pairs and lone drakes began dispersing from the study area after mid-June. Nests were located opportunisticly in conjunction with other activities. Nest information �52 recorded included species, number of eggs present, egg fertility, incubation stage, nest fate, and general habitat characteristics. Early morning and late evening brood surveys were initiated on 10 July and continued through 16 August, again using quiet observation. Unlike pair surveys however, we sampled only a selected subset of the wetlands present in each study unit. This was done primarily to increase the probability of obtaining repeated counts on individual duck broods. For each brood observed we recorded the species, brood size, duckling age (Gallop and Marshall 1954), presence or absence of the hen, wetland location, and time of day. An attempt was made to observe each brood at least once a week. Wetland habitats were categorized using a classification system (Cowardin et al. 1979) modified specifically for montane wetlands. Information included in this system included wetland origin (moraine or beaver created), dominant vegetative class (submergent, floating leaf, emergent, moist soil, shrub, or organic bottom), water permanency (percent of water surface lost from basin during the summer) and beaver activity. Other supplementary information recorded for each wetland included the relative impacts from human disturbance and cattle grazing as well as the percentage of the pond basin dominated by submergent, floating leaf, emergent, woody, and moist soil vegetation. A cover map of each wetland was drawn to scale for later use in calculating pond size with a hand planimeter. From these data, we calculated total surface water available in late May within 200 m of each wetland. The mean distance from each wetland to its 6 nearest neighbors and the total number of ponds within 200 m were calculated from study unit maps and aerial photographs. Habitat selection analyses were performed using all these variables in a stepwise regression procedure for predicting wetland pair and brood use days. RESULTS Species Composition and Breeding Chronology Nine waterfowl species were observed in the study area (Table 2). Mallard was the most abundant nesting species (40.6%), followed by ring-necked duck (23.7%), green-winged teal (13.5%), cinnamon teal (Anas cyanoptera; 8.5%), bufflehead (8.5%), and American wigeon (Anas americana; 5.1%). Other nonbreeding species included Canada geese (Branta canadensis), wood duck (Aix sponsa) and common merganser (Hergus merganser). Nesting chronologies were estimated from known age broods using literature values for average clutch size, incubation periods (Erskine 1972, Klett et al. 1986), and fledging dates (Gallop and Marshall 1954). Peak nest initiation for waterfowl occurred between mid-May and early June, with mallards and buffleheads the earliest nesting species and ring-necked ducks the latest. Consequently, most ducklings hatched between mid-June and mid-July and fledged sometime in August. Based on estimated hatching dates, the length of the nesting season varied among species (Fig. 6). Mallards had the longest breeding period of any species, extending over 8 weeks, followed' closely by green-winged teal at 7 weeks. Although sample sizes for cinnamon teal, ringnecked duck, and bufflehead are small, their nesting seasons appeared shorter, with none of them exceeding 3 weeks in length. Since the extended breeding seasons for mallards and green-winged teal lacked a definitive peak, some renesting may have occurred. Except for a few mallards, most drakes left the study area by early July to undergo post-breeding molt. �53 en 7 o o 6 rn 5 ••••• o 4 10- 3 "'C - Mallard - Green-winged teal CJ American wigeon cs::Sl Cinnamon teal 1",,1 Ring-necked duck [ZJ Bufflehead Io- Q) ..c 2 ::J 1 E Z o , 1 I 2 I 3 I 4 I 5 , I 6 7 9 Weeks Figure 6. Number of duck broods hatching each week on the Routt National Forest, Colorado, 1989. Week 1 corresponds to week of 25 - 31 May. 10 �54 Table 2. waterfowl Species composition, abundance, and nesting chronologya breeding in the Routt National Forest, Colorado, 1989. for Mean date of Incubation Hatching commencement Species Number of pairs Nest initiation Mallard 24 20 May 28 May 23 June 18 August 8 29 May 7 June 30 June 4 August Green-winged teal Fledging Cinnamon teal 5 2 June 11 June 4 July 12 August American wigeon 3 1 June 9 June 3 July 21 August 14 7 June 16 June 11 July 31 August 5 15 May 27 May 25 June 16 .August Ring-necked Bufflehead duck a Based on backdating known age broods. Sample sizes are in parentheses: mallard (13), green-winged teal (6), cinnamon teal (2), American wigeon (1), ring-necked duck (4), and bufflehead (2). Because individual birds were not marked, m~n~mum home range sizes of pairs and broods were determined based on conservative assumptions using species identification, age class, brood size, and behavioral associations with other ducks. Our confidence in assigning individual identities was higher for broods than for pairs. In general, dabbling duck pairs moved more frequently than diving duck pairs, and lone males moved more frequently than pairs. However, few individuals traveled more than 500-600 m from their core area of use, and most simply appeared to move between the closest set of available, preferred wetlands. Brood movements were variable and highly dependent upon wetland isolation. Broods using moraine ponds rarely moved during the entire brood rearing period, whereas those using strings of beaver ponds used several ponds within a 300-400 m area. Pair Density A total of 59 pairs of breeding ducks were observed on the 4 study units. Overall pair densities for this area averaged 6.1 pairs/km2 (Table 3), but was not uniform among units. The NFN Platte and Goose Creek had the highest densities with 9.5 and 9.2 pairs/km2 respectively, whereas Shafer and Forester Creeks had the lowest with 3.7 and 3.1 pairs/km2. Species were distributed proportionally among all 4 units, except for cinnamon teal, which were only observed in the Goose Creek unit. �55 Table 3. Estimated number National Forest, Colorado, Species of pairs using Study Unit Forester N. Fork N. Platte Mallard Green-winged each study unit in the Routt 1989. teal Goose Shafer Total 11 3 8 2 24 2 1 2 3 8 Cinnamon teal 0 0 5 0 5 American wigeon 2 0 1 0 3 3 2 6 3 14 1 1 1 2 5 19 7 23 10 59 Ring-necked Duck Bufflehead All species Table 4. Weekly changes Forest, Colorado, 1989. in lone male to pair ratios on the Routt National Week May June June June June July Species 26-29 5-8 12-15 19-22 25-28 4-7 Mallard 0.9:1 1. 6: 1 5.5:1 3:1 5:1 3:0 7:1 5:0 2:1 3:0 1:1 0:0 Green-winged teal Cinnamon teal 3:1 4:1 4:1 2:0 0:0 0:0 American wigeon 0:1 0.3:1 2:0 0:0 0:0 0:0 0.2:1 0.3:1 2.2:1 1. 7: 1 2.3:1 0:1 0.3:1 2:1 2:0 0:0 0:0 0:0 0.7:1 1. 2: 1 3.3:1 2.4:1 3:1 3:1 Ring-necked Duck Bufflehead All species The ratio of lone males:pairs increased for all species as the breeding season progressed (Table 4). Once lone males began appearing in large numbers, only a few pairs of mallard, green-winged teal and ring-necked ducks �56 re-appeared in the population. Dates reflecting the lone male:pair ratio reversal corresponds closely with the estimated start of incubation for wigeon, ring-necked duck, and bufflehead based upon brood ages (Table 2). For mallards, the sharp reduction in pair numbers occurred approximately 2 weeks after the estimated peak in incubation (based upon brood ages), but it occurred at least 2 weeks prior to the estimated start of incubation for both teal species. Not all females disappeared during June, however. At least 34 lone female buffleheads were observed during all times of the day after midJune, a period when they should have been incubating. Nest Success Due to the abundance of available nesting cover, the strong site tenacity of incubating females, and the lack of time in which to conduct a thorough nest searching operation, only 2 mallard nests were discovered. Both of these nests were found during early egg laying while conducting pair counts along wetland margins. One nest was abandoned because of our disturbance, but all 8 eggs in the other nest eventually hatched. Although several other hens were flushed from vegetation adjacent to wetlands or observed returning from incubation breaks, none of their nests could be located. Without a larger sample size, a definitive estimate of nest success is not possible. However, inferences based on the low re-pairing rates and the high brood sighting:pair ratios suggest that overall hen success (percent of hens that nest successfully) in this part of the Routt National Forest is at least 50% and more likely around 70%. Brood Survival A minimum of 28 broods were observed on the 54 wetlands we surveyed regularly. Of these, at least 15 (53.6%) fledged or were class lIb or older when last sighted. Assuming that all of these broods fledged young with no further mortality, mean duckling survival was 4.1 young/brood fledged (Table 5). The largest fledging brood had 9 ducklings, the smallest only 1. Overall production was at least 6.3 ducklings/km2, or 1.1 fledged young/pair. However, since only a subset of wetlands surveyed for pairs were checked for broods, it is likely that some broods were unrecorded. Also, some broods (i.e. mallards and teal) were very difficult to relocate due to visibility factors, and may well have fledged young without our knowledge. Assuming 60 pairs of ducks in the study area, 70% hatching success, 65% brood survival, and 4.1 ducklings/brood fledged; waterfowl production in the area could have been as high as 10.7 ducklings/km2 or 1.7 fledged young/pair. Minimum/maximum production figures for each species ranged from 3.6-4.5 ducklings/km2 for mallards to 0.0-0.3 ducklings/km2 for wigeon. As with pair data, individual study units were not equivalent in their waterfowl production (Table 6). The NFN Platte unit fledged at least 10.0 ducklings/km2, compared to only 4.5-6.3 ducklings/km2 for the other 3 units. Despite having the largest number of fledging broods, Goose Creek also had the lowest mean brood size at fledging, thus countering its overall impact on production. �57 Table 5. Observed and best estimates National Forest, Colorado, 1989. for duckling Mallard Green-winged teal on the Routt No. of young fledged 2 km er 2er breeding 2air 2 observed estimated observed estimated -No. of fledgedbroods young Species production 7 35 3.6 4.5 1.5 1.7 2 6 0.6 1.4 0.8 1.6 Cinnamon teal 1 4 0.4 0.9 0.8 1.8 American wigeon 0 0 0.0 0.3 0.0 1.0 3 9 0.9 2.5 0.6 1.7 2 7 0.7 0.9 1.4 1.8 15 61 6.3 10.5 1.1 1.7 Ring-necked duck Bufflehead All species Table 6. Observed duckling production National Forest, Colorado, 1989. Unit No. of fledged broods young within each study unit on the Routt No. of voung fledged per breeding pair per km2 N. Fork N. Platte 4 20 10.0 1.1 Forester 3 16 6.3 2.3 5 13 5.5 0.6 3 12 4.5 1.2 Goose Shafer Creek Creek Creek Duckling survival rates using 15 broods with known fates suggested a dichotomy between date of hatch and pond type. Nests that hatched prior to 26 June had an average of 5.4 ducklings/fledged brood, compared to only 2.8 ducklings/fledged brood for those hatching later (E = 0.07, Van der Waerden Test). Although not statistically significant, broods using beaver ponds fledged an average of 4.5 ducklings/brood compared to just 2.8 for moraine ponds (E = 0.38). Duckling survival rates declined sharply for the first 2 to 3 weeks following hatch, then stabilized at about 4.0 ducklings/brood (Fig. 7). The deflated values calculated for class II broods are primarily the �58 "'C 0 0 7 .c <, 6 ~ C) C 5 0 4 :::J ~ •••• 3 ~ Q) 2 E 1 Z 0 0 .c :::J la lib Age Class Figure 7. Mean brood size by age class for all duck species combined, Routt National Forest, Colorado, 1989. �59 result of 3 large broods (R = 8.3 ducklings) which were not observed while members of these age classes. Inflated values for class III broods reflect the absence of 5 small, late hatching broods (R = 2.1 ducklings) which were too young to qualify for this class when brood observations were terminated. Habitat Use Examination of the correlation matrices for the 17 habitat variables indicates that they basically reflect 3 separate wetland factors: pond size, origin and dominant covertype (Table 7). The remaining 14 variables are Variables correlated with pond sizea, pond or~g~n, and dominant in the pond, Routt National Forest, Colorado, 1989. Table 7. covertype Correlated Basin variables size 0.98** Permanency Wetland Habitat Pond origin -O.ll Factors Dominant covertype -0.09 -0.00 -0.71** 0.10 0.07 0.53** -0.02 intensity -0.00 0.53** 0.03 disturbance 0.03 0.61** 0.01 Beaver activity Grazing Human Pond size % Water 0.17* % Submergent cover % Floating leave % Emergent cover cover -0.01 -0.04 -0.19* 0.42** -0.66** 0.41** -0.46** -0.22* 0.10 -0.51** -0.02 % Woody cover -0.28* 0.70** 0.06 % Moist soil cover -0.23* 0.16* 0.12 -0.21* 0.73** -0.10 0.15 -0.71** 0.03 Number Mean ponds/200-m distance/6 Total water nearest surface/220-m 0.10 0.04 -0.06 a pond size = portion of pond conta~n~ng water in May, pond or~g~n = beaver or moraine created, dominant covertypes in pond are ordered from deepest to shallowest. b.r. < 0.05" .r. < 0.0001 "* �60 related to these 3 as follows. Larger ponds tended to have more floating vegetation and less woody cover than did smaller ponds. Ponds dominated by submergent or floating leaf vegetation had a greater percentage of their basins filled with water. And finally, beaver created ponds tended to (1) be closer together, (2) more permanent, (3) more likely to contain active beavers, (4) have greater impacts from grazing and human disturbance, and (5) contain a higher percentage of submergent, woody, and moist soil vegetation, but less floating leaf vegetation than ponds of glacial origin. Use of wetlands by waterfowl pairs was strongly related to pond size (Fig. 8), with pond origin a minor secondary factor (Table 8). The best single predictor of pair use among related pond origin variables was the amount of human disturbance around the wetland. Pond size was the most influential variable affecting pair use for mallard, ring-necked duck and bufflehead. Pond size was less important for green-winged teal, cinnamon teal, and wigeon. Pond origin, whether predicted best by human disturbance, grazing intensity, or beaver activity, was a secondary factor for all species, with preference towards beaver created ponds. Table 8. Wetland characteristics best explaining on the Routt National Forest, Colorado, 1989. Dependent variable Species Independent observed variablesa + Disturb Surwtr (0.65)""'''b Mallard Surwtr (0.52) *"" + Disturb (0.02)* Surwtr (0.11) (0.03)* Surwtr (0.10)*** Su rw t r (0.43) ""'* + Disturb Su rw t r (0.50)., ....• Cinnamon teal Ring-necked Bufflehead teal Duck *"* + Disturb + Graz + Beav (N (partial R2) 160) (0.06)""''' Pair Use Days Green-winged pair use + Class (-0.01)* (0.09)*** (0.05)"" (0.01)" a Surwtr = pond water surface area in late May, Disturb = relative human disturbance, Class = dominant vegetation class of wetland basin, Graz = cattle grazing intensity around wetland, and Beav = beaver activity in wetland. b f < 0.0001 ***, f < 0.01 "*, f < 0.05 " Because not all wetlands were surveyed for duck broods, habitat selection within this reproductive phase may be biased. Nevertheless, like pairs, pond size was the principal factor explaining brood use for all species but teal (Table 9). Significant secondary factors included ponds dominated by floating leaf vegetation for all broods combined and pond origin (active beaver ponds) for mallards. �61 en :10.. -- Wetland size clas ••• 120 0- 0-200, 201-400, 401-800,801-1600,1601-3200,3201-6400, 6401-12,800,12801-25,120, CO <, (ha)' ascending and' 25,121 ord.r. 100 en "'C c 0 £:::,. 80 o 0•••••• 0 :10.. Q) ..c E ::J Number of ponds Pair use 60 o 40 £:::,. 0 o 20 Z c: o - 0 o o 3 4 o o c: 0 I 0 1 2 Wetland 5 6 7 8 9 Size Class Figure 8. Total pair use days and number of ponds available within selected wetland size classes, Routt National Forest, Colorado, 1989. in �62 Table 9. Wetland characteristics best explaining on the Routt National Forest, Colorado, 1989. Dependent variable Species Brood Use Days Mallard Green-winged Cinnamon teal Ring-necked Bufflehead teal Duck Independent Surwtr (0.58)**~ Surwtr (0.53)*** Surwtr (0.13)** Graz observed variablesa + % Water brood use (N 56) (partial R2) (0.03)* + Beav (0.09)** (0.08)* Surwtr (0.22)** Surwtr (0.32) *** a Surwtr = pond water surface area in late May, % Water = % of basin covered by water, Graz = cattle grazing intensity around wetland, and Beav beaver activity in wetland. b f < 0.0001 "", f < 0.01'" f < 0.05 * Since larger ponds provide more surface area/pond for duck pairs to occupy, a strong relationship between pond size and the number of waterfowl use-days should be expected. Thus the mere existence of such a relationship does not necessarily indicate actual preference by duck pairs for big ponds. In order to separate these 2 relationships, we divided the ponds into 4 size classes and calculated pair density/ha of surface water available (Table 10). Once again pair use increased with pond size, with large ponds having nearly 3 times the pair density of small ponds. Pair densities for American wigeon, ring-necked duck, and bufflehead all increased as pond size increased, whereas mallard and the teal species showed no consistent trend. As a result, dabbling ducks were the dominate group in the smaller wetland classes while diving ducks dominated in the largest size class. A similar analysis for brood was performed, but since it has to be corrected for observational effort, is thought to contain some bias. An analysis of nest site selection was not possible because of insufficient sample size. However, both nests which were discovered had similar cover and site characteristics. Each was located in a thick island clump of Carex along the edge of a wetland about 1 to 2 m from shore. Other unconfirmed sites based on hens flushing or observing hens returning from incubation breaks were in similar habitats. However, at least one mallard hen returning from an incubation break headed straight into the forest. A mallard brood was later seen on this pond, thus it seems likely her nest was in the nearby forest. �63 Table 10. Duck pair densities within selected Routt national forest, Colorado, 1989. wetland size classes Wetland Size Classes {ha}a 0.1 - 0.2 0.2 - 0.8 on the Species < 0.1 Mallard 0.8 2.4 1.4 1.6 0.6 0.2 0.9 0.3 Green-winged teal > 0.8 Cinnamon teal 0.4 0.4 0.3 0.6 American wigeon 0.0 0.0 0.0 0.3 0.2 0.4 0.9 2.3 0.0 0.0 0.3 0.9 2.1 3.5 3.9 6.2 90 88 67 45 10 12 33 55 Ring-necked duck Bufflehead All species % Dabblers % Divers (N = 88) (N = 59) a Total amount of water (ha) available 0.2 = 4.6, 0.2-0.8 = 11.7, > 0.8 = 12.1. in each size are: < 0.1 4.8, 0.1- Several other important wetland habitat variables were noted qualitatively during the course of the investigation. Invertebrate populations were sampled in emergent vegetation along several wetland margins in late May and early June, and large numbers of snails, leeches, fresh water shrimp, and other small crustaceans were found. Most ponds appeared to have a sufficient number of invertebrates to support local waterfowl pairs. Although we did not sample during the summer months, invertebrate densities likely dropped in many of the moraine ponds when most emergent vegetation and several entire ponds dried up as the summer progressed. As a result, invertebrate densities for broods were probably lower and more patchy in their distribution than they were for pairs. Upland nesting cover was readily available, especially around beaver ponds where dense thickets of willows and sedges were common. Moraine ponds generally had less available cover, since most were surrounded by lodgepole pines with little understory. Even so, there were still numerous sites with tall brush, windfall timber, and thick wetland vegetation for hiding nests. Potential nest cavities for bufflehead may have been more limiting because (1) large aspens were generally absent from many suitable ponds due to past beaver activity and (2) northern flickers (Colaptes auratus), which are the main cavity excavators, were uncommon on the study area. Water quality in the study wetlands was excellent; no major upstream impacts such as forest fires, clear-cutting, mining or other commercial �64 development activities have taken place for at least for several decades. Water stability in the beaver ponds (except those in the Cinnamon drainage) is dependable throughout the summer. In contrast, the moraine ponds appear to be in a current drought cycle and, based on historical aerial photographs, have likely been in decline since 1984. Several moraine ponds went dry before the end of the brood rearing period this year. Without significant snowfall this winter, most of them will probably be in extremely poor condition next spring. DISCUSSION Breeding pair densities in this portion of the Routt National Forest were much higher than either the 1.4 pairs/km2 reported by Rutherford and Hayes (1976) or the 0.6 pairs/km2 found by Frary (1954) in forested habitats elsewhere in Colorado. Compared to grassland associations (Bellrose 1979), our observed dabbling duck density of 4 pairs/km2 is almost equal to that found on the short and tall grass prairies (6-8 pairs/km2), but is much lower than that on the mixed grass prairies and parklands (24-30 pairs/km2). Species compositions were also different from other montane studies. Although mallards and green-winged teal were commonly found in all 3 studies, we had no nesting gadwall (Anas strepera; Rutherford and Hayes 1976), and several species considered uncommon elsewhere were much more abundant in our study area. These included cinnamon teal, ring-necked duck and bufflehead. In fact prior to this study, no breeding records of bufflehead had existed in the state of Colorado (Ringelman and Kehmeier 1989). Wetland use by waterfowl pairs was strongly related to pond size. Large ponds may be more attractive to ducks because they provide a greater degree of water permanency, a more dependable food supply, better access in a forested environment, and more available space for inclusion within a pair's horne range, thus reducing the need to divide time among several smaller, more scattered wetlands. Large wetlands may provide enough space for 2 or more pairs of the same species. Also, because of their greater range of water depths, large ponds may offer a more diverse habitat which can be exploited by several different duck species simultaneously. Wetland habitat diversity leads to greater species diversity, which translates to greater use days/pond. A secondary factor influencing habitat use by waterfowl pairs was pond origin. Wetlands created by beavers had greater use than did those formed by glacial action. Of the 14 related pond origin variables, human disturbance was the one most correlated with pair use. Beaver ponds which experienced the heaviest fishing activity tended to be those located close together in large complexes or series. Such complexes were most attractive to fishermen if they also contained a few large, deep ponds with good trout potential scattered among the group. Duck pairs attracted to these larger wetlands also readily used smaller, neighboring ponds, which in some cases were only 3 to 5 m away over a beaver darn. As a result, small wetlands that might not have been used had they been located in a more isolated situation experienced greater than expected pair use. This heterogeneous nature of beaver pond complexes likely increased the effective size of each wetland member, attracting pairs in densities similar to those of larger individual wetlands. In summary, because of the large number and diversity of breeding ducks attracted to this part of the Routt National Forest, it appears that there is an adequate amount of wetland habitat and a sufficient mixture of different wetland types available. If one also considers the large early season �65 invertebrate populations, the abundance of suitable upland nesting cover, and the reliable sources of May pond water, this area probably provides as high a quality wetland base for nesting waterfowl as one will find at this elevation. The only limiting factor in this phase of the reproductive cycle may be the availability of nesting cavities for buffleheads. Based on the general lack of re-pairing and the high proportion of pairs for whom broods were observed, nest success appears to be very high in the Routt National Forest. Our estimated rate of 50% to 70% nest success is much higher than the 10% to 15% commonly found in the northern prairies (Cowardin 1983). These high rates are most comparable with those obtained from intensively managed lands (i.e. nesting islands, peninsula cut-offs, electric fenced fields) throughout the prairie pothole region (Lokemoen et al. 1982, Duebbert et a1. 1983). Potential nest predators in our study area included striped skunk (Mephitis mephitis), coyote (Canius 1atrans), mink (Mustela vison), badger (Taxidea taxus), long-tailed weasel (Mustela frenata), and common raven (Corvus corax). However, few of these species were abundant and widespread. Other possible sources of nest loss were from flooding (in early July all irrigation ditches previously diverting water for hay in North Park were shut off to prepare fields for harvesting) and inclement weather (i.. e. snow, hail, falling trees). Overall, these other events probably effected only a small portion of the total clutches initiated. Consequently, this portion of the Routt National Forest appears to be as safe a nesting area as those managed with much greater intensity and financial resources. Brood survival rates varying from 27% to 81% have been reported (Ball et al. 1975, Ringelman and Longcore 1982, Talent et al. 1983, Duncan 1986). Since our observed rate of 54% and estimated rate of 65% is in the upper range of these values, total brood loss is probably not excessive. Mean brood sizes at fledging for all these previously cited studies was around 5.0 - 5.5 ducklings. Similarly, Frary (1956) found average brood sizes of 5.6 ducklings for mallard and green-winged teal in the montane habitat of northwest Colorado. Thus the mean brood size of 4.1 ducklings estimated for the Routt National Forest is slightly below that expected, indicating that partial brood loss may be a problem. Reasons for this increased rate of duckling attrition are largely speculative. On numerous occasions we observed that brood cohesion was relatively weak, even for class I ducklings. Downy young were often seen scattered about the pond feeding alone or in small groups, becoming strung out behind females while traveling through thick floating vegetation, or being left behind when females moved to neighboring beaver ponds 10 to 300 m away. Orphaned ducklings are likely to die from predation or exposure during frequent mountain thunderstorms and chilly nights. In addition, many broods were forced to feed away from cover, since water levels in beaver ponds were too stable for an emergent cover zone to develop and moraine ponds were too unstable for this zone to contain water past early July. This exposure increases their likelihood of succumbing to predators or environmental factors. By mid-summer, only the deeper floating leave, submergent and open water zones were available for broods. Because the emergent zone is shallower and has correspondingly greater light intensities, it has greater primary production and stem density than does the deeper submergent zone (Westlake 1965, Moss 1980). This productivity and habitat complexity in turn supports an abundant and rich diversity of invertebrates (Moss 1980), a critical food �66 source for ducklings during their first 2 weeks of life (Sudgen 1973, Reinecke 1977). The shallow water of the emergent zone may help concentrate these invertebrates so they can be more easily reached. Without emergent areas, ducklings are forced to search for food in deeper water zones where invertebrate densities may are generally lower, more unevenly distributed and more difficult to reach. Invertebrate biomass also tends to decrease with the age of beaver ponds (Reinecke 1977). Based on aerial photographs, most beaver ponds in our study area appeared to be more than 15 years old. Thus, while emergent vegetation zones are available in spring, reduced availability and productivity during summer may create local food shortages for ducklings. If such a food shortage hypothesis is correct, one might expect ducklings to (1) spend more time searching for food, (2) spread out more while feeding to reduce competition with siblings, (3) have increased chances of being separated from the rest of the brood, and (4) be in poorer body condition and hence more suspectable to cold, disease, and predators if separated. One might also expect brood females to frequently switch ponds in search of better feeding areas, particularly if alternatives wetlands were close by. Larger wetlands might be more attractive to brood hens because of their greater degree of water permanency, greater likelihood of containing water lilies and perhaps other submergents, and higher probability of constant beaver activity maintaining a dynamic wetland community. Earlier hatching broods might be expected to have higher survival rates than later hatching broods due to the better water conditions present and more abundant food resources available earlier in the year. Beaver ponds might fledge more ducklings than moraine ponds due to their more diverse submergent zones, the possibility of beavers raising their dams and flooding new upland cover, and the presence of small beaver channels offering some protected shallow water feeding areas. Thus the ultimate factor most likely limiting waterfowl production in this section of the Routt National Forest is the lack of cover and reduced food supplies caused by the gradual loss (or lack of) flooded emergent vegetation as the season progresses. MANAGEMENT RECOMMENDATIONS Duckling survival appears to be the phase of the reproductive cycle most limiting waterfowl production in the Big Creek Lakes area of the Routt National Forest. Buffleheads may lack enough suitable nest cavities. Other potential bottlenecks such as pond numbers, wetland quality, nesting cover, and rates of nest loss appear to be of little or no concern. Thus all management efforts are best directed at improving duckling survival rates and bufflehead nest sites, two actions which will return the largest benefit per dollar invested. Brood separation and subsequent duckling losses due to exposure or predation, resulting from insufficient amounts of flooded emergent cover, appears to be the factor most likely causing smaller than expected broods at fledging. Dense concentrations of cowlilies on many ponds probably contribute to brood separation and impede efforts by the hen to regroup ducklings. The dominant emergent plants currently found on the study area are 3 species of sedges, all typically found growing in < 0.3 m of water (Windell et al. 1986). Consequently, they are very susceptible to drying out in moraine ponds and unlikely to become established in beaver ponds, since the latter �67 usually have deep waterline edges caused by beavers collecting mud for their lodges and darns. For improving waterfowl production, we suggest that an emergent species having a wider range of water depth tolerances be introduced into the area. The most promising candidate is hard-stern bulrush, which grows in acidic, fresh, or slightly alkaline water up to 1 m deep and is found in dense stands at Lake John (2553 m) and another site in the Routt National Forest (2530 m), both less than 30 krn away. Establishing this species is relatively easy; individual root stocks should be firmly shoved into a soft bottom in either spring or fall at rates of 1000 plants/acre (Lemberger 1981). Since the study area is at the upper elevational limits for this species, it might be best to arrange the plantings in several large clumps in order to assure some individuals survive and establish a strong network of rootstocks. Attempts to establish hardstem bulrush stands from seeds may be more difficult because of the need to scarify seeds (spring seeding) or control water levels (fall seeding) (Harris and Marshall 1960), and because the colder sediment temperatures at this elevation may cause poor germination. In order to improve duckling mobility on ponds with dense cowlily growths, we suggest using an aquatic herbicide (such as Rodeo, a trademarked product from Monsanto) to create a 3 m network of travel lanes throughout a pond. Since beavers readily feed on cowlilies, once such channels are established these rodents may continue to maintain them for their own use. Beaver activity on several ponds is currently maintaining an attractive mix of open water and lily beds. However ponds that are very large or have not had beavers occupy then for several years are completely choked. Thus this management technique should be regarded as more of a supplemental method of improving waterfowl production than as a permanent large scale necessity. Buffleheads will readily use artificial nesting boxes (Gauthier 1988). These should be constructed with maximum dimensions of 15 x 15 x 40 cm with a 6.5 cm hole in order to minimize competition with other species. Since buffleheads seem to prefer choosing from several sites, 3 or 4 boxes should be placed around each wetland. Higher use and success rates will most likely occur from boxes placed 3 to 7 m high in heavy coniferous forest, close to the wetland edge with few obstructions in front of them. Since bufflehead pairs were only observed on the larger wetlands or beaver pond complexes, nesting box efforts should be concentrated on such wetlands, particularly those currently used by buffleheads. For each of these 3 management recommendations, we suggest selecting 2 wetlands in each experimental unit (NFN Platte and Goose Creek) for purposes of the evaluation. In order to avoid cross experimental effects, a separate wetland should be selected for each treatment. Thus a total of 12 wetlands will be used (Table 11). A similar set of 12 wetlands should be identified in the 2 control units (Forester and Shafer Creeks). This will allow for both wetland and unit comparisons during the 2 year evaluation, an important consideration since there will be multiple treatments occurring simultaneously in each experimental unit. The effectiveness of each management technique will be determined by the difference in mean brood size at fledging between the 1989 pre-treatment data and the 1990-91 treatment data, adjusted for any such changes occurring in the control units during this same time (nonexperimental effects). A fourth management recommendation, which is separate from the other 3 because there is no available replicate, is that of rejuvenating a series of 19 beaver ponds in the so-called "cinnamon drainage" within the Goose Creek �68 Table 11. Wetlandsa recommended for specific management action in the experimental units along with those wetlands designated as being their experimental controls. Management Treatments wetlands N. Fork N. Platte Goose action Hard-stern bulrush Herbicide Bufflehead a planting spraying nest boxes See Figures 2-5 for the exact Control Forester wetlands. Shafer 67,86 35,53 1,41 20,23 80,85 18,33 26,42 14,18 13,83 22,37 15,50 22,28 location of each wetland listed. unit. This drainage system, which had 5 or 6 breeding pairs of ducks in May, fledged only 1 brood totaling 4 ducklings. A major reason for this poor production is that little beaver activity has occurred in this area since 1980, based on annual growth rings of previously damaged trees (Lawrence 1952). As a result, many of the beaver darns are deteriorating and no longer hold water. Although the area has extensive groves of aspen saplings that should be attractive to beaver, very little water flows through the complex after 31 May. An upstream beaver pond complex has changed flow patterns so that most of the water is currently being diverted away from the cinnamon drainage. To rejuvenate this series of ponds, we recommend using 2 sets of beaver tubes (Laramie 1963) to divert a small amount of water from a beaver pond located on Goose Creek into a second beaver pond complex, then out into the cinnamon drainage (Fig. 9). This will likely attract beavers to recolonize the area, repair the present darns, and re-flood the ponds. These new ponds should provide an abundant source of invertebrates for ducklings as well as additional habitat for breeding pairs and broods. This portion of the Routt National Forest is very high quality waterfowl habitat, with pair densities that rival some prairie breeding areas and nest success rates that exceed all but the most intensively managed waterfowl habitats. If one or more of our proposed recommendations prove effective, the Forest Service will have an outstanding example of the waterfowl production potential that exists in some forested habitats. By using the methodologies and results from this study to improve areas of similar or lower quality, enhanced waterfowl production with continental significance could be achieved. In addition, habitat information indicating that waterfowl pair use is highly correlated with pond size and origin can be readily incorporated- into predictive models. Such models, when combined with remote sensing technology, could prove invaluable for estimating total waterfowl production and identifying areas where waterfowl management projects exist on other National Forest land in Colorado. �~ iu W 0: o WM C/) o o o \ \ ~, " - . " "I (.._.r.-.. -.~..--. ---__./'/ . I \..- : I 69 ~, ,,- * �70 LITERATURE CITED Ball, I. J., D. S. Gilmer, L. M. Cowardin, and J. H. Reichman. 1975. Survival of wood duck and mallard broods in north-central Minnesota. Wildl. Manage. 39:776-780. J. Bellrose, F. C. 1979. Species distribution, habitats, and characteristics breeding dabbling ducks in North America, Pages 1-15 in T. A. Bookhout (ed.), Waterfowl and wetlands-an integrated review. La Crosse Printing Co., Inc., Wisc. Colorado Division of Wildlife. 1989. Colorado state waterfowl plan. Colorado Division of Wildlife, Fort Collins, CO. management Cowardin, L. M., V. Carter, F. C. Golet, and E. T. LaRoe. 1979. Classification of wetlands and deepwater habitats of the United U.S. Dept. Interior FWS/OBS-79/3l. 103pp. Cowardin, L. M., A. B. Sargeant, potentials for prairie ducks. and H. F. Duebbert. Naturalist 34:4-11. Duebbert, H. F., J. T. Lokemoen, and D. E. Sharp. of mallards and gadwall on Miller Lake Island, Mange. 47:729-740. 1983. 1983. North A. J. Frary, L. G. Colorado. 1972. Buffleheads. Can. Wildl. States. Problems anp Concentrated nesting Dakota. J. Wildl. Duncan, D. C. 1986. Survival of dabbling duck broods on pra~r~e in southeastern Alberta. Can. Field-Nat. 100:110-113. Erskine, of Servo Monogr. impoundments Ser. 4. 240 pp. 1954. Waterfowl production on the White River Plateau, M. S. Thesis, Colorado State University, Ft. Collins. Gauthier, G. 1988. Factors affecting nest-box use by buffleheads cavity-nesting birds. Wildl. Soc. Bull. 16:132-141. 93 pp. and other Gollop, J. B. and W. H. Marshall. 1954. A guide for aging duck broods the field. Unpublished report, Mississippi Flyway Council Tech. Sec., 14 pp. (mimeo). in Harris, S. W. and W. H. Marshall. 1960. Germination and planting experiments on soft-stem and hard-stem bulrush. J. Wildl Manage. 24:134-139. Klett, A. T., H. F. Duebbert, C. A. Faanes, and K. F. Higgins. 1986. Techniques for studying nest success of ducks in upland habitats in the prairie pothole region. U.S. Fish Wildl. Servo Resour. Publ. 158. 24 pp. Laramie, H. A. Jr. 1963. Manage. 27:471-476. Lawrence, W. H. 1952. Manage. 16:69-79. A device Evidence for control of problem of the age of beaver beavers. ponds. J. Wildl. J. Wildl. �71 Lemberger, Wise. J. J. 1981. 32 pp. What brings them in? Wildlife Nurseries, Lokemoen, J. T., H. A. Doty, D. E. Sharp, and J. E. Neaville. fences to reduce mammalian predation on waterfowl nests. Bull. 10:318-323. Moss, B. 1980. Ecology of freshwaters. Inc., New York. 332 pp. Halsted Press, Oshkosh, 1982. Wildl. Electric Soc. & John Wiley Sons, Reinecke, K. J. 1977. The importance of freshwater invertebrates and female energy reserves for black ducks breeding in Maine. Ph.D. Dissertation, Univ. of Maine, Orono. 113 pp. Ringelman, J. K., and J. R. Longcore. 1982. Survival of juvenile during brood rearing. J. Wildl. Manage. 46:622-628. Ringelman, J. K., and K. J. Kehmeier. Colo. Field. Ornith. (in press). Buffleheads breeding black in Colorado. Rutherford, W. H. and C. R. Hayes. 1976. Stratification as a means improving waterfowl surveys. Wildl. Soc. Bull. 4:74-78. Sudgen, L. G. and lesser 1973. scaup for Feeding ecology of pintail, gadwall, American wigeon, ducklings. Can. Wildl. Servo Rep. Ser. No. 24. 45 pp. Talent, L. G., R. L. Jarvis, and G. L. Krapu. 1983. Survival broods in south-central North Dakota. Condor 85:74-78. Walters, C. J. 1986. Press, New York. ducks Adaptive 374pp. management of renewable of mallard resources. Macmillan Westlake, D. F. 1965. Some basic data for investigators of the productivity of aquatic macrophytes, p. 231-248. In C. R. Goldman (ed.), Primary productivity in aquatic environments. Mem. 1st. Ital. Idrobiol., 18 Suppl., Univ. of California Press, Berkley. Windell, J. T., B. E. Willard, D. J. Cooper, S. Q. Foster, C. F. Knud-Hansen, L. P. Rink, and G. N. Kiladis. 1986. An ecological characterization of Rocky Mountain montane and subalpine wetlands. U. S. Fish Wildl. Servo Biol. Rep. 86(11). 298 pp. �72 APPENDIX A. CLASS VARIABLE CODING SHEET Dominant wetland covertype 1 submergent 2 floating 3 emergent leave 4 moist 5 woody 6 organic 2 beaver soil Pond origin 1 = moraine Water Permanency Beaver 1 0-10% 4 51-70% 2 11-30% 5 71-100% 3 31-50% I active activity o Grazing = inactive intensitv by cattle 1 none 4 extensive 2 slight 5 severe 3 moderate Relative degree of human disturbance 1 none 4 extensive 2 slight 5 severe 3 moderate �73 APPENDIX B. DUCK PAIRS CENSUS ED ON THE ROUTT NATIONAL FOREST, COLORADO. Week of 29 May, 1989. Unit S:Qecies Mallard Lm ." If. b pro C North Fork of North Platte 3 0 8 Forester Creek Goose Creek 0 6 0 3 1 1 Shafer Creek 2 0 0 Total 11 1 12 Lm . Greenwinged teal lf. pro 3 0 0 0 0 0 1 0 1 3 0 0 0 1 Cinnamon teal 1m. lf. pro 0 0 0 0 0 0 3 0 1 0 0 0 3 0 1 Ring-necked duck Lm . 1f. pro 1 0 2 0 0 2 1 0 5 0 0 3 2 0 12 American wigeon 1m. 1f. pro 0 0 1 0 0 0 0 0 1 0 0 0 0 0 2 Bufflehead 1m. if. pro 0 0 1 0 0 1 0 0 1 1 0 1 1 0 4 Common merganser 1m. If. pro 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 All species 1m. if. pro 7 0 0 6 11 1 10 6 0 13 0 4 24 1 33 Appx. no. pairs 20 6 22 10 58 alone males b10ne females "pa i r s 7 �74 Appendix B. (Continued) 1989. Week of 5 June, Unit SI2ecies Mallard 1m. a If.b pr. C Greenwinged North Fork of North Platte 3 1 4 Forester Creek 4 1 1 Shafer Creek Total 13 3 8 4 2 0 3 1 0 1 0 0 5 0 0 1m. teal If. pro 2 0 0 1 0 0 1 0 0 1m. 1f. pro 0 0 4 0 4 0 0 0 0 0 0 1 0 1 1m. 1f. pro 1 0 2 0 0 1 Cinnamon teal Ring-necked duck American wigeon 1m. If. pro 1 0 0 1 0 0 1m. 1f. pro 1 0 0 0 1 0 1m. If. pro 0 0 0 1m. 1f. pro Appx. no. pairs Bufflehead Common merganser All species alone males b10ne females "pa i r s Goose Creek 0 1 0 0 4 3 0 0 1 0 3 0 10 1 0 3 2 0 0 1 0 0 2 0 1 3 1 0 2 0 2 0 0 0 0 0 0 0 0 8 1 7 5 2 11 4 28 0 3 6 2 10 4 24 16 7 21 10 54 2 �75 B. (Continued) Appendix Week of June 12, 1989. hens with broods. Bold face type denotes nesting hens; italics indicates Unit SIlecies Mallard 1m. a If.b pro C Greenwinged 1m. teal If. pro North Fork of North Platte 3 1,1,1 0 Forester Creek 1 1,1 1 Goose Creek 1 0 Shafer Creek 2 1 0 5 Total 11 2,3,2 1 2 0 0 0 0 2 1 0 2 1 0 0 4 0 4 Cinnamon teal 1m. 1f. pro 1 0 0 0 0 0 3 1 1 0 0 0 4 Ring-necked duck 1m. 1f. pro 1 0 0 2 0 0 9 0 2 1 0 13 0 4 6 American wigeon 1m. 1f. pro 0 0 0 0 0 0 2 0 0 0 0 0 2 0 0 Bufflehead 1m. If. pro 1 0 0 0 0 0 1 0 0 0 1 0 2 1 0 Common merganser 1m. If. pro 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 All species 1m. 1f. pro 9 1,1,1 0 3 1,1,1 3 21 4 1,1 2 5 4 37 3,3,2 12 1 1 alone males "Lone females "pa i.r s .: �76 Appendix Week of June 19, 1989. hens with broods. B. (Continued) Bold face type denotes nesting hens; italics indicates Unit North North S12ecies Mallard Greenwinged 1m. a If .b pr. C 1m. teal If. pro Fork of Platte 0 Shafer Creek 1 0 0 0 0 0 0 1 0 3 0 0 1 0 0 2 0 Forester Creek 2 2,2,1 0 0 0 0 Goose Creek 0 3 Total 3 5,2,3 0 3 Cinnamon teal 1m. If. pro 0 0 0 0 0 0 2 1 0 0 0 0 2 1 0 Ring-necked duck 1m. lf. pro 1 0 0 1 0 0 7 0 2 1 0 4 10 0 6 American wigeon 1m. If. pro 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Bufflehead 1m. If. pro 0 0 0 0 0 0 0 1 0 0 1 0 0 2 0 Common merganser 1m. If. pr. 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 All species 1m. lf. pro 1 2 0 3 2,2,2 9 5,1 18 8,2,4 3 3 5 1 4 alone males blone females cpairs 7 �77 Appendix Week of June 26, 1989. hens with broods. B. (Continued) Bold face type denotes nesting hens; italics indicates Unit North North S2ecies Mallard Greenwinged 1m. a 1f. b pr. C 1m. teal lf. pro Fork of Platte 1 0 0 Forester Creek 4 4,1 2 Goose Creek 2 2 0 Shafer Creek 3 1,1 0 0 1 0 1 0 0 0 2 1 0 0 0 3 Total 10 3,4,2 2 1 1 Cinnamon teal 1m. lf. pro 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 Ring-necked duck 1m. If. pro 1 0 1 1 0 0 3 0 1 2 0 1 7 0 3 American wigeon 1m. If. pro 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Bufflehead 1m. lf. pro 0 2 0 0 0 0 0 1 0 0 3 0 0 6 0 Common merganser 1m. 1f. pro 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 All species 1m. If. pro 2 6 4,1 2 5 5 2,1 4,2 4,1 1 18 10,4,5 6 alone males b10ne females cpairs 1 2 �78 Appendix W'eek of July 3, 1989. hens with broods. B. (Continued) Bold face type denotes nesting hens; italics indicates Unit S:gecies Mallard North Fork of North Platte Lm .a If.b pr. C Greenwinged 1m. teal If. pro 0 1 Shafer Creek 3 1,1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Forester Creek Goose Creek 0 1 1 4 0 0 0 0 0 Total 7 2,2 Cinnamon teal 1m. If. pro 0 0 0 0 0 0 0 0 0 0 0 0 Ring-necked duck 1m. If. pro 0 0 0 0 2 0 0 0 2 1 1 1,1 1 1m. 1f. pro 0 0 0 0 0 0 0 0 0 0 0 1m. If. pro 0 2 0 0 0 0 1 3,1 0 0 0 0 0 0 Cornmon merganser 1m. If. pro 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 All species 1m. If. pro 0 4 2 1 1 9 6,5 0 0 3 3,1 1 American wigeon Bufflehead alone males blone females cpairs 1 0 1 0 2,3 1 1 1 0 2 �79 APPENDIX OBSERVATION C. LOG FOR EACH INDIVIDUAL BROOD Brood Species 2) Green-winged 3) Green-winged teal teal 4) Mallard 5) Mallard size age" F-43 6-6 8 Ia Yes F-41 6-20 5+ >Ia Y F-43 6-27 8 Ie Y G-21 6-19 6 Ia Y G-24 6-26 7 Ib Y G-24 6-26 3+ Ia Y P-6 6-14 7+ Ia Y P-35 6-21 7 Ib Y P-16 6-28 6 Ic Y P-6/15 7-10 5 lIb Y P-19 7-14 2+ lIb y P-14 7-25 5 II No P-13 8-15 5 Juv N P-37 6-21 8 Ia Y 8-2 8 III N P-6/7 6) Green-winged 7) Mallard teal Hen present Date pond 1) Mallard No.a P-6 6-28 2+ Ia Y S-18 6-29 2 Ib y S-18 7-7 2 Ic Y S-18 7-13 2 IIa Y .: �80 Appendix c. (continued) age Hen present Brood Species pond No. Date size S-18 7-19 2 lIb Y S-18 7-26 2 IIc Y S-18 8-16 2 juv N 8) Mallard S-18 6-29 5 Ic Y 9) Bufflehead F-SO 7-5 7 Ia Y F-50 7-14 7 Ib Y F-50 7-19 6 Ib y F-50 7-21 6 Ic y F-50 7-26 6 IIa Y F-50 8-1 7 lIb Y F-SO 8-4 6 lIb Y F-50 8-8 5 IIc Y F-SO 8-11 5 IIc Y F-SO 8-16 5 III ~ P-13 7-6 6 Ia Y P-79 7-6 6 Ia Y P-83 7-6 6 Ia Y P-83 7 -13 4 1b y P-83 7-18 1 Ie Y P-83 8-8 2 IIc Y 7) Mallard 10) Ring-necked 11) American 12) Mallard duck wigeon .: �81 Appendix C. (continued) Brood Species 13) Cinnamon 14) Cinnamon pond No. teal teal 15) Green-winged teal 16) Bufflehead 17) Ring-necked duck Date size age Hen present G-45 7-11 5 Ia Y G-45 7-16 2 Ib N G-45 7-21 6 Ie N G-50 7-24 5 IIa N G-45/50 8-14 4 juv N G-18 7-10 4 Ie Y G-18 7-24 3 IIb Y F-50 7-12 7 Ia Y F-50 7-19 1 Ib Y F-50 7-26 3 Ie Y F-50 8-1 1 IIb Y F-50 8-11 2 lIe N $-18 7 -13 2 IIb Y S-18 7-19 2 IIb Y $-18 7-26 2 lIe Y $-18 8-3 2 III y S-18 8-10 2 III N $-18 8-16 2 Juv N P-83 7-13 6 Ia Y P-83 7-18 6 Ib Y P-83 7-25 6 IIa y �82 Appendix C. (continued) Brood Species pond No. Date size age Hen present P-83 8-1 5 IIb Y P-83 8-8 4 IIc Y P-83 8-14 5 IIc Y F-SO 7-14 7 III Y F-SO 7-19 3+ III Y F-SO 7-26 9 III Y F-SO 8-1 6 Juv N F-SO 8-4 6 Juv N F-SO 8-8 8 Juv N F-SO 8-16 7 Juv N F-IS 7-14 8 Ia Y F-21 8-9 1 lIb Y 20) Mallard G-21 7-17 1 IIa Y 21) Mallard G-30 7-19 2 Ic Y G-18 7-20 3 Ic Y G-19 8-1 2 lIb Y G-19 8-4 2 IIc Y G-24 8-14 1 IIc y G-IS 7-17 6 Ia Y G-IS 7-20 3+ Ia Y G-IS 7-21 6 Ia Y 17) Ring-necked duck 18) Mallard 19) Mallard 22) Ring-necked duck �83 Appendix C. (continued) Hen present Brood Species 22) Ring-necked 23) Green-winged pond No. duck teal 24) Mallard 25 ) Ring-necked duck 26) Mallard 27) Green-winged 28) Mallard teal Date size age G-18 7-24 6 Ib Y G-18 7-27 5 Ib Y G-19 8-1 1 Ic Y G-21 8-14 1 lIb N G-2l 8-29 1 III N G-18 7-17 4 IIc Y G-2l 8-4 4 III N P-68 7-18 5 Ia Y G-18 7-24 3 Ic Y G-18 7-27 3 Ic Y G-2l 8-1 2 IIa Y G-18 8-7 3 lIb Y G-18 8-14 3 IIc Y S-28 8-3 8 III N S-28 8-3 2 Ia Y S-28 8-11 2 Ib Y P-54 8-8 2 lIb Y a Wetland letter codes are as follows: P = N. Fork N. Platte, Creek, G = Goose Creek, and S = Shafer Creek. b Age classes flying young. are after Gallop and Marshall (1954). Juv F Forester juvenile or ��85 Colorado Division of Wildlife Wildlife Research Report September 1990 JOB PROGRESS REPORT State of Colorado Project 01-03-212 Work Plan 22 Job Title: Author: : Job Migratory Period Covered: Migratory Game Bird Research _2_ Bird Publications 01 April 1989 through 31 March 1990 Michael R. Szymczak Personnel: James K. Ringelman Wildlife and Michael R. Szymczak, Colorado Division of ABSTRACT The following list contains those articles that were prepared and/or submitted for publication or published during this segment: Ringelman, J. K., W. R. Eddleman, and H. W. Miller. 1989. High plains reservoirs and sloughs. Pages 311-340 in L. M. Smith, R. L. Pederson, and R. M. Kaminski, eds .. Habitat management for migrating and wintering waterfowl in North America. Texas Tech Press, Lubbock. Ringelman, Colorado. J. K., and K. J. Kehmeier. 1990. Colo. Field Ornithol. 24:46-48. Ringelman, J. K. 1990. Buffleheads. Buffleheads Colo. Outdoors. breeding in 39:8-9. Ringelrnan, J. K. 1991. Differential harvest of male and female mallards under conventional and point system regulations. Wildl. Soc. Bull. (submitted for review) Ringelman, J. K. 1991. Evaluating and managing waterfowl Colorado. Colo. Div. Wildl. Spec. Rep. (In prep.) habitat in Rusch, D. H., C. D. Ankney, H. Boyd, J. R. Longcore, F. Montalbano III, J. K. Ringelman, and V. D. Stotts. 1989. Population ecology and harvest of the American black duck: a review. Wildl. Soc. Bull. 17: 379-406. � https://cpw.cvlcollections.org/files/original/11b497b1e4d395bd13b75c856f99532e.pdf 534ccfcb3cdee989760316c875b0b6c9 PDF Text Text 1 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o _ Project: (W-150-R-4) Period Covered: 1 July, 1990 - 30 June, 1991 : Peregrine Falcon Restoration Program Personnel: G.R. Craig, Colorado Division of Wildlife and J.H. Enderson, The Colorado College. ABSTRACT In the 1991 peregrine breeding season, 58 territories were occupied by 49 breeding pairs that fledged 91 young. The West Slope subpopulation consisted of 42 occupied sites while East Slope occupancy increased to 16 sites. Eggshell thicknesses in 1990 averaged 10.2% thin. Contents of 12 nonviable eggs that were analyzed for organochlorines yielded relatively low levels. Due to population numbers, fostering and hacking efforts were discontinued. This Job Progress Report represents a preliminary analysis and is subject to change. For this reason, information presented herein MAY NOT BE PUBLISHED OR QUOTED without permission of the author. ��3 PEREGRINE FALCON RESTORATION PROGRAM Gerald R. Craig SEGMENT OBJECTIVES 1. Annually monitor the number of breeding pairs of peregrines and their reproductive success in Colorado. 2. Annually monitor organochlorine peregrines in Colorado. 3. Monitor breeding population turnover through band recoveries, presence of color markers, and telephotographic identification of individual breeding adults. 4. Augment poor wild production by placement of captive hatched wild young and captive produced young into occupied wild nests. 5. Release captive hatched and captive produced young at potential and vacant wild territories. 6. Monitor recruitment of reintroduced peregrines into the wi ld breeding population of Colorado. pesticide levels in wild breeding METHODS AND MATERIALS 1. Visit all known peregrine breeding territories throughout Colorado and observe them from a distance to establish the presence of breeding adults. Breeding pairs will be kept under surveillance to determine initiation of egg laying. Depending upon the individual female's reproductive history and eggshell condition (obtained through measurement of previous year's eggshell thicknesses) and availability of captive hatched young for release, breeding pairs either will monitored or manipulated as outlined in approach 4. Those pairs not designated to be manipulated will be revisited periodically throughout the nesting season to document reproductive success. When a pair's behavior indicates that egg laying has occurred and incubation is underway, the eyrie wi 11 be visited to document the number of eggs produced. The eggs will be candled to ascertain viabi 1ity and approximate age. All nonviable eggs will be collected for chemical analysis. A second visit will be made to determine productivity, band nestlings, and collect eggshell fragments and unhatched eggs for thickness measurement and analysis under 2a and 2b. 2a. Eggshell fragments encountered during eyrie visits described in approaches 1 and 4a will be measured for index to thickness following standardized procedures. 2b. Whole, nonviable eggs which are encountered during eyrie visits will be collected, preserved and submitted to the appropriate Fish and Wildlife Service approved -laboratory for pesticide analysis. Eggs collected from the wild in the course of Approaches 4a, 4b and 4c that are artificially �4 at the Peregrine Fund's Boise, Idaho facility also will be submitted for shell thickness measurement and chemical analysis. 3. Peregrines present at breeding territories will be examined to determine the presence of bands or color markers. Band confi rmation will be accomplished through observation from a distance with telescopes and concealed remote controlled cameras. When banded falcons are encountered, every effort wi 11 be made to read band numbers without trapping or hand1 ing the bi rds. It is possible this can be accompl ished in most situations with a Questar field model telescope (80-130x). When band numbers cannot be discerned, attempts will be made to trap and examine the falcon at a time when capture will have least impact upon breeding activities. 4a. In accordance with an annual release plan developed and approved by the state, U.s. Fish and Wildlife Service, Bureau of Land Management, National Park Service, and the Forest Service, a predetermined number of wi ld breeding pairs will be manipulated to augment natural productivity. Pairs with a history of reduced clutch size, cracked eggs, or infertile or dead eggs will be candidates for fostering efforts. 4b. On occasion, it may be necessary to recycle several early breeding pairs in order to delay them until captive hatched young of the proper age are available for placement into wild sites. No later than 10 days after the last egg has been deposited, the eyrie will be visited and the entire clutch removed without replacement. Approximately 14 days after removal of the clutch, the pair will recyc 1e, se1ect anothe r nest 1edge, and deposit a second clutch of eggs. If the eggs are thin shelled, they may be replaced with plastic replicas and treated as outlined in approach 4a. This technique also works well to augment captive production with wild produced eggs. 4c. At times, pairs will select inferior eyrie ledges that may compromise nest success such as ledges that are too narrow to support a brood of large nestlings, the site may be vulnerable to predators, or it may be exposed to the elements. If the ledge cannot be mechanically improved, pairs can be relocated to other ledges through the recycling method described in approach 4b since they invariably relocate and select a new ledge when recycled. 5. In accordance with an annual release plan developed and approved by the State, U.S. Fish and Wildlife Service, Bureau of Land Management, National Park Service, and the Forest Service, a predetermined number of captive produced falcons will be released at unoccupied or potential sites through the technique of hacking. This technique is employed at locations that do not have the benefit of protection or care from adults. Young falcons of about 35 days of age will be placed in a hack box on a suitable cliff ledge at the reintroduction site. They wi 11 be fed and cared for by attendants until they are flying and capable of fending for themselves. This technique assures that the young become familiar with their surroundings and hopefully will return to the site as adults and take up residency. Hacking requi res constant attendance and observation to protect the vulnerable young and assure they have sufficient food while they are dependent upon the hack site. While the hack sites wi 11 be �5 operated by the State, actual costs to operate the sites will be borne by the appropriate land administering agency (Forest Service, Bureau of Land Management, and National Park Service). 6. Confirmed breeding territories and selected potential breeding sites will be surveyed annually to document the presence of released falcons and ultimately determine the success of recovery efforts. RESULTS AND DISCUSSION Territory Occupancy Breeding territory occupancy increased from 44 sites in 1990 to 58 in 1991 (Table 1). The expansion was due to reoccupancy of two historical sites (sites 21 and 23), discovery of 10 previously unreported sites (sites 65 through 74) and reoccupancy of five sites (25, 33, 41, 51 and 54) that were vacant in 1990. Eight of the ten sites that were discovered in 1991 were situated on cliffs that had been surveyed and found to be vacant in the past. West Slope nesting pairs continued to expand (Table 2) with 42 sites occupied by 40 breeding pairs. East Slope site occupancy increased to 16 sites with reoccupancyof 2 historical sites (Sites 21 and 23) and addition of 5 new territories (Sites 65, 68, 69, 70, and 72). Reproduction Due to the population increase, no remedial efforts such as fostering or hacking were undertaken in 1991. Peregrine productivity in 1991 averaged 2.28 young fledged per successful pair (40 pairs fledged 91 young) and 1.72 young fledged per total pair (53 pairs fledged 91 young)(Table 3). The 42 occupied sites on the West Slope fledged 75 young (1.79 young per occupied territory) while the 16 East Slope sites produced 16 fledglings (1.00 young per occupied territory) (Table 2.). The lower productivity of the East Slope may be due in part to presence of inexperienced breeders. Although site 39 started the fourth year with an the adult male peregrine paired with a female prairie falcon, she was replaced by a first year female peregrine. They did not produce eggs. Eggshell Condition First clutch eggshell fragments representing 19 nests were collected in 1991. The shell thickness (with membrane) from that sample averaged 12.0% thin (0.316 mm). Since fragments were encountered during nest visits, their origin from each egg could not be ascertained. Since thickness varies as much as 5% from the egg waist to the poles, random fragments can be expected to deviate by that amount. More accurate thickness measurements from the waist of whole eggs encountered at 9 sites yielded 0.322 mm (10.3% thin) which is similar to the 1990 average. �6 Individual eggshell thicknesses continued to vary wildly. As an example, Site 18 produced eggshells that were normal thickness (0.353mm) while an egg from Site 31 was 22.8% thin (0.277mm). Organochlorine Residue in Eggs Results of chlorinated hydrocarbon scans of 12 nonviable whole eggs encountered at eight wild nests in 1990 have been received. All the residue levels were low. DOE values ranged from 2.4ppm to 7.5ppm (fresh wet weight) and total PCB's ranged from 0.54ppm to 7.5ppm. The 9 whole eggs that were collected in 1991 will be submitted for analysis. Prepared By:_ ____:Ce-=::;....:......:...;;?;...·__;:6=...;;..;;.CV-_,.;.~~.__ Gerald R. CraigJ Wildlife Researcher C �Table 1. OCCUPANCY OF PEREGRINE BREEDING TERRITORIES IN COLORADO SITE PRE NO.1964 1964 1965 - 1966 1967 -- 1968 1969 1970 P P P 1 P 2 P P + P A P 3 + P A A 4 + M P 5 6 7 8 V 9 + 11 A P P 12 A M 13 + 14 F P + 15 + 16 + 17 + 18 V + 19 + 20 V + V 21 + A 22 23 V + -------------------------~-------------------------------(Htstortcal 24 25 26 27 28 29 30 31 32 33 34 35 37 + 38 39 40 41 - -- - - -- - -- = -- - --- --- ----- -- -- - - --- - - - -- --- - --- --- -- -- - - - --- --- --- -- = - -- - ----- - - -- --- P P P P P -- V V V V -- V - 1971 1972 1973 1974 1975 1976 - P P P P p P p P P P A P p p p p V P P P P P p p p p V A V V V V V V V M V P P P V p P V V P V V V V V V V V V V V M V P P p1 V V V V p1 M P - ----- V - - -- -- - --- - -- --- - - - - - - - V V V V ---- -- = V V A F4 - --- V A --- - V V V V - - - - - ---- - --- -- -- -- - -- --- - P P V M V V V p1 V P p5 V V P V V V V V V V V V V V V V V V V V V stt8S p p p p --- - ---- --- - - - = 1977 1978 V V V V V V V V M V p1 P P P V V P P V V V V V V P P V V V V V V V V V V V V V V V V V V abov8 thts p V p V p3 P p p P M p P p p p1 --- M -- F Lone adult female. M Lone adult male. A Lone adult. P Adult patr. 2:Imm. male & ad. female. 3:Ad. female replaced by tmm. 1 Ad. male & imm. female. 6:Ad. male dead tn vtcintty. 5 Ad. male replaced by tmm. male mtdway. 7:Imm. male 9 Ad. male paired with female prairie falcon. 1979 1980 V V V V P p1 p2 V V V V p1 1981 1982 1983 1984 1985 V V V V P V V V V V p1 p1 V V P V V V V P p1 M V V V F V V V V M P F V V V V V V V P P P P P P P P P1 V V V V P F V P V V V V V V V V V V V V V V V p1 V P M V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V ltn8)--------------------------------------------------------V V V M M V V V P P P P P P M V V V V V V M8 P F P P P P V V V P V V V A V V V V V V p p p p p p p P M P P P P P M V V V V V V p p V V P V V p1 P P P P P P P P P P P - --- - - - -- - - - p6 p P P p p1 - - P p1 V P 1986 1987 1988 P V P P P V V P V P V V V V P V V V V V V V P V P P P V P V P P V V V V P V F V V V V V P P P p1 V P V P V V p 1989 1990 1991 P V P V P P P V V V P V P V V V V V P P P P P V P V P P V V V V P V P V V V V F P P P P P V P V P P p1 V P V P V P p V P V P V P p V P V P V P p V V V P V P P V V P P P V M P P p1 P p1 P P V P P P P P P P P P P P P p9 P P V P P P P p9 P P P P - P P P p1 V V V P V P V V V V V p P~ P V P P P P P V P V P P P V V' V P V P V V P V P V P V P V P P P P P P P P P p1 P F = V Vacant site. female midway. 4:0ead & female. 8:Imm. male. ad. female found in victnity. '"'-J �Table 1 (cont.). OCCUPANCY OF PEREGRINE BREEDING TERRITORIES IN COLORADO SITE PRE NO.1964 1964 1965 1966 19117 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 p 42 43 44 45 46 48 1985 1986 1987 1988 1989 1990 1991 P p p p p p p p p p P P p P P p p p1 P p2 V P M p p p p p p p P P p p p p p p p p p1 49 50 51 52 V V V P p9 p9 V V P p P 53 54 p F 55 F p p p 56 57 58 P V P V p P p p 59 60 61 P p p p 62 63 64 66 v 67 68 v v 69 p p V A P P M p p P A P p p p p 70 V V V V V V V V V V v V V V V V V V V V v V 72 73 74 p p P 65 71 p p p A = Lone adult. F = Lone adult female. M = Lone adult male. P = Adult pair. V = Vacant site. 1:Ad. male & imm. female. 2:Imm. male & ad. female. 3:Ad. female replaced by imm. female midway. 4:Dead ad. female found in vicinity. 5:Ad. male replaced by imm. male midway. 6:Ad. male dead in vicinity. 7:Imm. male & female. 8:Imm. male. 9:Ad. male paired with female prairie falcon. P M F P �9 Table 2. COMPARISON OF EAST AND WEST SLOPE SITE OCCUPANCY West SloQe Occupied Sites Breeding Pairs Young Produced Young Hacked 73 74 75 76 77 78 79 80 81 82 83 84 85 11 9 7 7 10 9 11 11 11 11 13 13 13 1 4 4 3 8 6 4 5 6 6 8 11 12 a 10 5 4 11 16 12 16 15 20 21 26 26 a a a a a a 5 7 10 8 15 18 12 East SloQe Occupied Sites Breeding Pairs Youn£, Produced Young Hacked 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 CUM 3 2 1 1 2 2 2 2 a a 1 1 1 2 5 8 7 9 16 3 2 1 1 1 a a a a a a 1 1 1 3 2 4 6 9 2 3 a 3 0 a a a a a a 3 2 2 10 5 6 11 16 63 a a a a a 4 5 4 3 5 8 9 12 10 19 26 25 12 a 110 86 19 17 32 4 87 24 20 45 88 24 22 44 89 32 27 60 90 35 33 51 a a a a 91 CUM 42 40 75 435 a 79 �10 Table 3. Site 1 2 3 4 5 7 9 11 12 16 18 21 23 25 27 29 30 31 32 33 34 35 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 Male A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A Age Female Sumary of 1991 Peregrine Production Eggs 1st 2nd Clutch Clutch Young Hatched Young Fostered Young Fledged A A A A A A A A A A A A A A A + 3+ 3+ 3+ 2+ 2+ 4+ 0 2+ 4 2+ 1+ 4 4 2 1 4 + 3+ 3+ 0 3+ 2+ 0 3 2 3 3+ 4 3 1 0 2 1 0 A A A A A A A 2+ + 2+ + 2+ 3+ 2+ 2 2+ 2+ 0 1 3+ 2+ 2 I I 0 2 2 2 1 2 0 0 2 2 A A A A A A A A A A A A A A A A A A A 2+ 2+ 2 4+ 2+ 3+ 4+ 2+ 3+ 3+ 3+ 2+ 3 2+ 3+ 2+ + + 3+ 3+ 4 2+ 3 4 2+ 3 3+ 3+ 2+ 3 2 3 2+ 2 2 3 4 2 2 3 3 2 1 1 3 2 1+ 3+ 3+ 1 2 3 A A A + 3+ 3 2 3+ 2 2 3 2 A A A A A A A 2+ 3+ 3+ + + 3+ 2+ 2+ 3+ 3+ 0 0 2+ 2+ 2 3 3 0 0 2 2 A 2+ 2+ 2 Total Sites Occupied: Total Breeding Pairs: Total Young Produced: Average Fledged Brood Total Fledglings + 58 49 100+ Size: 2.28' Total Total Total Young Adult Pairs: 51 Successful Pairs: 40 Young Fledged: 91 Fledged Per Total Pair:1.72 Divided by Total Successful Pairs �..l.J.. JOB PROGRESS REPORT State of P roject: __ ---"'C=o....:..lo;:::_r:....:a=d=o:..._ _ Bald Eagle Nest Site Protection and Enhance__l.(..!.!W_-..!.,;15~1!,_-....:..R~-=3.L.) _ ment Program Period Covered: 1 July, 1990 - 30 June, 1991 Personnel: G.R. Craig, Colorado Division of Wildlife, R.L. Knight, Colorado State University, and R. McLean, Center for Disease Control. ABSTRACT Breeding bald eagles occupied 13 Colorado nesting territories in 1989. Two new territories was located in each of Mesa and Weld counties. Nine pairs successfully fledged 19 young. Samples of feather pulp and blood sera to determine genetic similarity of the Colorado population to adjacent populations were collected from 13 nestlings representing 6 sites. This Job Progress Report represents a preliminary analysis and is subject to change. For this reason, information presented herein MAY NOT BE PUBLISHED OR QUOTED without permission of the author. ��13 BALD EAGLE NEST SITE PROTECTION AND ENHANCEMENT PROGRAM Gerald R. Craig SEGMENT OBJECTIVES 1. Monitor nest site occupancy and reproductive success. 2. Document survival rates and mortality factors. 3. Determine migration and wintering areas. 4. Determine if philopatry occurs in breeding eagles. 5. Determine nest site tenacity by individual breeding eagles. 6. Quantify nesting habitats and associated foraging areas in an effort to document nest site parameters conducive to improved reproduction. 7. Document pesticide contamination through eggshell measurement and chemical analysis of nonviable eggs. 8. Where necessary, occupancy. implement actions to stabilize nests and maintain METHODS AND MATERIALS This work will be a cooperative endeavor between the Division and Dr. Richard Knight of Colorado State University. 1. Annually visit all documented breeding sites to determine the presence of bald eagles. Pairs at territories will be documented by DWMs and other field personnel. Previously unrecorded pairs will probably be revealed in the course of aerial eagle and waterfowl flights. DWMs will confirm actual incubation from ground visits. 2. Occupied territories will be visited by DWMs periodically throughout the breeding season to determine hatch of young, nesting failures, etc. 3. In May and June, a Utility Worker will observe breeding eagles from a distance and endeavor to follow thei r movements to locate important foraging areas. Responses of eagles to various human activities and land uses will be recorded. 4. In June, when the young are determined to be old enough to band, sites will be visited by Craig and Knight to place a federal band on one leg and a colored, alpha numeric marker on the other. The color markers will permit identification if the young return in subsequent years. During the same nest visit the following will be recorded: Physical parameters such as tree species, height, DBH, condition, and dominance. Nest condition, size, and location. �14 Vegetative community and land use practices. In addition, collect prey remains, nonviable eggs and eggshell fragments. 5. Approximately 5cc's of blood will be collected from each blood will be analyzed at the Savannah River Ecology Lab Carolina. Electrophoretic examination will permit genetic samples collected from other populations in Saskatchewan, and Arizona, as well as determine the heterogeneity of the nestling. The in Aiken, South comparison with the Lake States Colorado birds. 6. When necessary, remedial actions will be taken to stabilize nests that are threatened by wind throw. Should the tree be decadent and in danger of falling, an artificial nest base may be placed in a suitable, adjacent tree. Action will be taken only after it has been deemed desirable to encourage the eagles to nest at the same location. RESULTS AND DISCUSSION Territory Occupancy Bald eagle nesting activities for Colorado are summarized in Table 1. In 1991, 13 territories (Adams, Archuleta, La Plata #1 and #3, Mesa, Moffat #1, #2 and #3, Montezuma #2 and #3, Rio Blanco #1 and #3, and Weld #3) were occupied. Two new territories (Mesa and Weld #3) were added in 1991. Although there is the slight possibility that the pair at Weld #3 may have relocated from Weld #1, it is unlikely, given the distance. According to the landowner, Weld #3 was occupied in the late 1950's and had 2 young, but failed when the adults were shot. Land Status The new territory at Weld #3 is on private land. The landowner is aware of the site and is protective of the pair. Land use in the area is livestock ranching. The pair at Moffat #2 relocated from private land across the river to a golf course. The pai r adjusted to golfers immediately below the nest and were successful. The golf course management and many of the patrons are aware and protective of their eagles. The new site at La Plata #3 is of Forest Service land. Its remote location insures minimal, if any disturbance. The Mesa site is also new. It is situated on an island in the river on land administered by the Colorado Division of Wildlife. This site has the potential for moderate to high disturbance. . Reproduction Reproductive efforts of the 13 pairs are summarized in Table 2. In all, 19 young were hatched and fledged by 9 pairs (2.11 young per successful pair) which yielded an overall productivity of 1.46 young per nesting attempt. Two broods of 3 young were encountered at Adams and Rio Blanco #3. Two sites (Archuleta and Mesa and Montezuma #2) were not visited because they failed to produce young. Montezuma #3 was not visited because the young had already fledged, and Moffat #1 was inaccessible because of mud. Because of �15 landowner hesitance, Rio Blanco #1 was not climbed, but 2 large young were observed from a distance. Thirteen young were banded at 6 locations (Adams, La Plata #1 & #3, Moffat #2, Rio Blanco #3, and Weld #3). Fish and Wildlife bands were affixed to the nestlings' right legs and red alpha-numeric bands with yellow flags were affixed to the ir 1eft 1egs. Blood samp 1es , cu 1men 1ength and foot pad 1ength measurements were obtained from the eaglets that were banded. Eggshell Condition No eggshell fragments or nonviable eggs were encountered in 1991. Banded Adults The adult female at Moffat #2 was banded with on the right leg with a rivet style USF&WS band. Most, but not all of the digits were read with a spotting scope. The prefix was obscured by a tar-like substance, but the last 5 digit were 3(?)4402. It was also possible that the adult male may have a olive green or brown band. Nest Stabilization Efforts In the course of the visit to the Adams site in 1989, one of the support wires to the artificial nest structure was found to be broken allowing the nest to list slightly. The site was revisited in the fall of 1989 and it was determined that additional nest material had caused the nest to drop approximately 6 inches where the support wire had broken. The structure was raised and stabilized by fastening one end of an 8 foot redwood 2X4 to the tree trunk below the nest and attaching the other end to the rim of the nest basket. In conjunction with two support limbs, the 2X4 formed and inverted tripod that should provide a secure nest support for many years. The eagles were present at the time of the nest modification and continued to occupy the nest in the 1991 breeding season. Climber access to the nests has been a problem for several years. The placement of nests in dead limbs at the top of decadent cottonwoods along with their bulk combine to make it almost impossible to climb into some nests. In past years, climbing efforts were aborted because of danger to the climber and the nest. In 1991, 1/4 inch cable loops were affixed to the most difficult nests to aid in gaining access on future visits. The cables were affixed in such a fashion that as additional nesting material is added, the loops will become incorporated into the nests and yet offer secure hand and footholds at critical points. Due to its cantilevered placement in the tree, the artificial nest structure at the Adams nest required a cable ladder that was affixed to an adjacent limb and was folded and stored on the underside of the nest. In all, 6 nests (Adams La Plata #3, Moffat #2 and #3, Rio Blanco #3 and Weld #3) were modified using this technique. Prepared by: G/(. (lfl<:u_~ G~raid R: Crai Wildlife Researcher C �•..... 0\ Table 1. Bald Eagle Nesting Efforts in Colorado 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 Site La Plata Co. #1 Moffat Co. #1 La Plata Co. #2 Grand Co. Montezuma Co. #1 Rio Blanco Co. #1 Rio Blanco Co. #3 Weld Co. #1 Montezuma Co. #2 Moffat Co. #2 Moffat Co. #3 Adams Co. Archuleta Co. Montezuma Co. #3 Weld Co. #2 La Plata Co. #3 Weld Co. #3 Mesa Co. 1egg IA IA IA IA 1yng 2yng 2yng 2yng -- 2yng 2yng 2yng -- -- -- Oyng ----- -- --.- ----- ------- --- -------- -- -- o Total Young Total Pairs Young/Occ. Terr. IA = Inactive ---- ----------- ----- ----- --- -- ------- -- ---- --- ------ ---- -- IA 1yng Oyng Oyng ---- ---- -- --- ---- --- ? ? ? ? -IA IA A 2yng IA IA A 1yng 2yng IA IA A 1yng 3yng 2yng IA IA IA IA A IA ? eggs 2yng 2yng -- 2yng -- -- ---- --- --- ----- ----- ----- ---- -- ---- ---- -- ---- -- -- -- ------ --- -- -- ? -- --- ---- -- ---- ? Oyng IA IA IA Oyng 2yng 2yng 2yng ---- -- -- ---- -- eggs 1yng IA IA IA 2yng Oyng eggs 1yng 1yng 1egg eggs eggs -- --- --- 2yng 2yng A IA IA 2yng 1yng IA 1yng Oyng IA 1egg 2yng --- ---- 1yng 1yng IA IA IA 2yng A IA 1yng 2yng 2yng 3yng IA IA IA 2yng 2yng IA 1yng 3yng eggs ? eggs 2yng IA IA 1yng 1yng -- eggs --- -- -- --- Oyng 2yng IA IA IA 2yng 1yng Oyng 1yng 2yng IA 2yng IA 1yng IA 2yng --- 1yng 2yng IA IA IA 2yng 3yng IA Oyng 2yng Oyng 3yng Oyng 2yng IA 2yng 2yng Oyng 1 4 4 4 1 0 3 6 2 6 6 5 10 8 16 13 19 1 1 2 2 3 3 1 3 4 2 4 5 10 9 8 10 10 13 0.00 1.00 2.00 2.00 1.33 0.33 0.00 1.00 1.50 1.00 1.50 1.20 0.50 1.11 1.00 1.60 1.30 1.46 A = Active �17 Table 2. Colorado Bald Eagle Nesting Efforts - 1991 Site Age of Birds Male Female Young Produced Young Fledged Comments Adams Co. Adult Adult 3 3 Archuleta Co. Adult Adult o o La Plata Co. #1 Adult Adult La Plata Co. #3 Adult Adult 2 2 Mesa County Adult Adult o o Moffat Co. #1 Adult Adult 2 2 Moffat Co. #2 Adult Adult 2 2 Moffat Co. #3 Adult Adult o o Montezuma Co. #2 Adult Adult o o Montezuma Co. #3 Adult Adult 2 2 Adults incubating, no eggshells found. Adults incubating, site not visited. Site not visited. Rio Blanco Co. #1 Adult Adult 2 2 Nest not climbed. Rio Blanco Co. #3 Adult Adult 3 3 Weld Co. #3 Adult 2 2 19 19 Total Adult 13 13 ~ disappeared part way through incubation. Eggs failed to hatch. not visited. Site not visited. Site ��JOB PROGRESS REPORT State of ~C~o~l~o~r=a=d=o _ Project: (W-156-R-2) Period Covered: 1 July, 1990 - 30 June, 1991 : Pawnee Grasslands Raptors Personnel: G.R. Craig, Colorado Division of Wildlife and Douglas G. Leslie, Colorado State University Data gathered for the latter half of 1989-90 field season was reported in the previous progress report. This segment was devoted to nest site analysis, digitizing spatial data, coursework, and comprehensive exams. Manuscript preparation and publication has been delayed until 1992. � https://cpw.cvlcollections.org/files/original/73dd7c9ecfbdd40e17d87d2450de8bad.pdf a549edc8a699b278a22534f9280f9b29 PDF Text Text 1 INTERIM FINAL REPORT Colorado State of: Proj ect: 3 Work Plan: Job Title: Period Author: Upland W-152-R 13a Sage Grouse Survival Covered: Marilet Personnel: : Job 01 January Bird Research Estimation, North Park, Colorado through 31 December 1990 A, Zablan C, E. Braun, Colorado Division of Wildlife; Zablan, Colorado State University G. C, White and M, A. ABSTRACT Sage grouse (Centrocercus urophasianus) band recovery data from a l6-year period in North Park, Colorado were summarized by age and sex. Computer programs BROWNIE and ESTIMATE were used to test for differences in survival rates between males and females and to generate annual survival rate estimates by sex and age class (subadult and adult). The null hypothesis that adult males and females had the same recovery and survival rates was rejected (f = 0.013). Survival rates for males differed by year (f = 0.007) and goodness-of-fit and likelihood ratio tests indicated that Model HI fit the male recovery data. Model HI assumes yearspecific and age-specific annual survival and recovery rates. Program ESTIMATE was used to demonstrate that the simplest model (Model 3), with constant survival and recovery rates across years, fit the female recovery data (f = 0,336), Survival rate estimates for males banded and released as adults ranged from 0% (0 - 19.9%) in 1985 to 84,6% (33.8 - 100%) in 1979 and averaged 38.4% (32,9 43,8%). Survival rate estimates for males banded and released as subadults ranged from 15,0% (0 - 37.5%) in 1986 to 100% (27.3 - 100%) in 1974 and averaged 51. 7% (40'.0 - 63.3%). Survival rate estimate for both age classes of females over years (not an average value) was 54.7% (50,1 - 59.2%). Program SURVIV was used to test hypotheses that weather variables had no effect on annual survival of male sage grouse, as annual differences in survival were not found for females. Annual weather differences in sprLng and winter precipitation and temperature were" incorporated in a logistic model for sur-vf.va l, estimation and were assumed to be responsible for yearly variation in recovery and survival rates. Incorporation of four weather covariates did not significantly improve model fit (f = 0.194 to 0.787). Recommended banding sample sizes for future studies were calculated with Program BAND2. These results and those from a study of grouped recovery effects on survival estimation will be included in a thesis to be completed by 01 December 1991 in partial fulfillment of requirements for the Master of Science degree from Colorado State University, Prepared by: e)f/gAl&h.xf~. Marilet A. Zablan Graduate Research Asst. Approved by: t/atY2.~ C'LaLt; E, Braun Wildlife Research Leader ��3 INTERIM REPORT Colorado State of: Project: W-152-R Work Plan: _3_: Job Title: Upland Bird Research Job ~ Responses Period Covered: Author: FINAL of Sage Grouse to Vegetation 01 January through 31 December Fertilization 1990 Orrin B. Myers Personnel: C. E. Braun, Colorado Division of Wildlife; White, Colorado State University O. B. Myers, G. C. ABSTRACT A dissertation is being prepared for partial fulfillment of a Ph.D. degree in wildlife biology, Department of Fishery and Wildlife Biology, Colorado State University. Completion of all degree requirements should be accomplished no later than December 1991. Four chapters will discuss directly the responses of sage grouse (Centrocercus urophasianus) to vegetation fertilization or will develop methodology used in evaluating sag~ grouse responses. Chapter 1 . describes field studies on the response of sagebrush (Artemisia tridentata) and sage grouse to nitrogen fertilization in North Park, Jackson County, Colorado. Sagebrush plants responded to application of 112 kg-Nfha in Fall 1985 with increased growth and increased levels of foliar crude protein. Foliar crude protein levels remained significantly elevated over controls in samples collected in Spring 1989. A second application of fertilizer in 1987 produced a less dramatic response by sagebrush. Overall, soil and foliar nitrogen decreased exponentially during the study, but gross morphological differences were evident for 3 seasons after treatment. Sage grouse used fertilized study plots for feeding significantly more often than adjacent unfertilized plots. The magnitude of the effect declined gradually for 3 years and then returned to control levels in the 4th season after treatment. Sage grouse use of A. 1. vaseyana plants was not affected by fertilization. I used captive-reared sage grouse to test whether sagebrush subspecies-specific feeding preferences of grouse were due to environmental learning and the relative availability of each subspecies. In chapter 2 I demonstrate the utility of Bradley-Terry models for estimating preference from pairedcomparison experiments, and show how the model can be reparameterized to account for factorial treatment structures. In Chapter 3 I use Bradley-Terry models and analysis of variance on balanced incomplete blocks to test whether birds raised in captivity and having equal access to each sagebrush treatment show any preference for or avoidance of sagebrush treatments. Initial forage selection was a random process for all but fertilized A. 1. vaseyana, which was avoided, but I detected preference for fertilized and unfertilized A. 1. wyomingensis over A. 1. vaseyana when cumulative intakes over 60 minutes were compared. Fertilization increased the intake of both subspecies, but �4 consumption of fertilized A. !. vaseyana was far below that of unfertilized A. ~. wyomingensis. In the final chapter I summarize results from single treatment digestibility trials. Wild-caught sage grouse performed poorly on all treatments, but birds were better able to maintain body mass on A. ~. wyomingensis treatments than on A. !. vasevana treatments. Analyses to evaluate the effects of fertilization on food quality are ongoing. Prepared by Approved by Clait E. Braun Wildlife Research Leader �5 INTERIM FINAL REPORT State of: Colorado Project: __ W~-~1~5~2_-~R~ _ Work Plan: 3__ : Job Job Title: Response of Selec.ted Avifauna Sagebrush Type Period Covered: Author: Upland Bird Research 17 01 January to Prescribed through 31 December Burning in the Big 1990 Lee A. Benson Personnel: Lee A. Benson and Wayne C. Leininger, Department of Range Science, Colorado State University; Clait E. Braun, Colorado Division of Wildlife ABSTRACT Sage grouse (Centrocercus urophasianus) numbers and spring habitat use were monitored at 3 sites b~rned in 1987 in Jackson and Moffat counties, Colorado. Burns ranged in size from 38 to 1200 ha and were within 1 kID of sage grouse leks. Two burns were wildfires while 1 site was a prescribed burn. The prescribed fire site burned in a mosaic pattern and resulted in 50% reduction in big sagebrush (Artemisia tridentata) canopy cover within a 38-ha area. The wildfires consumed nearly all sagebrush within the 120 and l200-ha sites. There was no sage grouse use of the smaller wildfire site. Sage grouse use of the 2 other sites was primarily restricted to areas with remnant patches of sagebrush. Sage grouse use of burns increased each year post fire, but numbers of male sage grouse counted on leks decreased in either the first or second year following fires at all sites. Numbers of males counted on the prescribed burn site and one of the wildfire sites increased in 1990 and returned to or exceeded pre-burn lek numbers. However, fluctuation in sage grouse numbers on leks post-fire did not differ from preburn levels. Prepared by aeQJ~J Lee A. Benson Graduate Research Assistant Approved by Clait E. Braun Wildlife Research Leader ��JOB PROGRESS REPORT Colorado State of: Project: W-152-R Work Plan: Job Title: ·8 Upland Bird Research Job _5_ Population Inventory and Habitat Use by Lesser Prairie-chickens in Southeast Colorado Period Covered: 01 July 1985 through 30 June 1991 Author: M. Giesen Kenneth Personnel: C. E. Braun, D. Clarkson, M. B. Dillon, S. J. Fellinger, K. M. Giesen, R. W. Hoffman, G. M. Kittel, T. B. Lundt, D. M. Picken, J. S. Slater, C. H. Wagner, and B. D. Will, Colorado Division of Wildlife ABSTRACT Lek density and. spacing, male breeding density, movements and home ranges, habitat characteristics of occupied rangeland, lek sites, nest sites, and flush sites of lesser .prairie-chickens (Tympanuchus pallidicinctus) were investigated in Baca County in southeastern Colorado from April to September 1986 through 1990. The number of active leks on the 4l.4-km2 study area ranged from 6 to 9 annually, with a mean distance between nearest leks varying annually from 1.24 to 1.44 km. There was a strong positive correlation between male breeding density and number of leks (£ - 0.92) but npt between male breeding density and average lek size (£ - 0.15). Average lek size ranged from 6.5 males/lek in 1990 to 10.2 males/lek in 1989. Helicopter surveys during the peak of hen attendance detected 13 of 15 active leks (86.7%) but only 7 of 15 leks (46.7%) 2 weeks after the peak of hen attendance. Roadside listening transects detected 20 to 100% of active leks within 1.6 km and varied with weather conditions, observer, and date. Home ranges (minimum convex polygon) of females (5.96 ± 8.18 km2) were larger than those of males (2 ..11 ± 1. 54 'km2). Combined home ranges of all birds from individual leks was estimated at 34.67 12.78 km2 (95% ellipse) to 46.30 ± 2 12.69 km (minimum convex polygon). Movements of hens from lek of capture to nest sites averaged 1.80 ± 1.04 km and ranged from 0.22 to 4.85 km. Habitat characteristics of the study area indicated bare ground comprised 75.7% of the area with grasses averaging 19.9% ground cover. Sand sagebrush (Artemisia filifolia) density averaged 2497 plantsjha and had 3.1% canopy cover. Residual vegetation in April and May had an average height-density of 0.98 dm. Lek sites were dominated by buffalograss (Buchloe dactyloides) and blue grama (Bouteloua gracilis). Most nests were adjacent to sand sagebrush or soapweed (Yucca glauca). Heights of shrubs, forbs, and grasses were taller at nest sites than at adjacent areas. Vegetative height above nest bowls averaged 50.7 cm. Vegetative parameters measured at grouse flush sites were similar to those measured at dependent sites for both males and females indicating little apparent selection for vegetation structure at summer feeding-loafing sites. ± �8 RECOMMENDATIONS 1. All known active leks should be visited during March - May each spring to document activity status (active, inactive, abandoned). Searches of known occupied habitats should be conducted annually from the ground or air to locate additional leks or leks that moved. 2. When possible, aerial searches of historic range within Colorado should be made in mid-April to document occupied rangeland and locate leks. 3. Population trend analysis should use lek density or total numbers of active leks rather than average lek size (number of males/lek). 4. Management of occupied rangelands should include maintenance of sand sagebrush and forbs, and bunchgrass height-density above 1.0 dm with adequate bunchgrass between 3.0 and 5.0 dm for nesting. 5. Suitability of rangeland for lesser prairie-chickens should be ascertained on the basis of sand sagebrush density and canopy cover, and canopy cover and residual height-density of native bunchgrasses in spring. �9 POPULATION INVENTORY AND HABITAT USE BY LESSER PRAIRIE-CHICKENS IN SOUTHEAST COLORADO Kenneth M. Giesen INTRODUCTION Both distribution and populations of lesser prairie-chickens in North America have decreased by > 90% from historic levels of the 1800's (Taylor and Guthery 1980). The exact historic distribution of lesser prairie-chickens is unknown, although early reports suggested they were abundant and widely distributed throughout their range (Bendire 1892, Judd 1905, Bent 1932, Baker 1953, Sands 1978). Aldrich (1963) indicated lesser prairie-chickens historically inhabited about 360,000 km2 in 5 states. Recent estimates suggest the current range of lesser prairie-chickens is restricted to 125,000 km2 (Taylor and Guthery 1980, Johnsgard 1973). Historic population estimates were crude but lesser prairie-chickens were reported to be common to abundant throughout their range at the beginning of the century (Bent 1932, Baker 1953, Bailey and Niedrach 1965, Oberho1ser 1974). Litton (1978) reported estimates of 2 million prairie-chickens in Texas prior to 1900. Density estimates for different habitats ranged from 1.0 to 14.6 males/km2 (Davison 1940, Jones 1963, Copelin 1963). If the historic range was 360,000 km2, then historic populations may have been in the millions of birds. Current North American breeding populations are estimated at 50,000 birds (Crawford 1980, Taylor and Guthery 1980). Historical evidence suggests that 'while lesser prairie-chickens were peripheral in Colorado, they were common to abundant in 6 southeastern counties (Baca, Prowers, Bent, Kiowa, Lincoln, and Cheyenne) and peripheral in adjacent counties (Loeffler 1983). Surveys for lesser prairie-chickens in Colorado since 1960 have documented breeding populations in Baca, Prowers, and Kiowa counties with an estimated population of < 700 birds (Hoffman 1963, Loeffler 1983, Rash 1985). The lesser prairie-chicken is currently classified as a threatened species in Colorado. The objective of the Colorado Division of Wildlife is to improve the status of lesser prairie-chickens through habitat manipulations, reintroductions or transplants, and other management approaches (Colo. Div. Wi1d1. 1983). However, basic information on habitat characteristics of rangelands currently occupied by lesser prairie-chickens in Colorado is lacking. Methods for documenting annual population changes or population responses to management programs also need to be evaluated. P. N. OBJECTIVES 1. Ascertain the relationship between the average number of males attending leks (lek size), the total number of active leks (lek density), and the number of lek-attending males (male breeding density) on the study area. �10 2. Measure the accuracy and pre~1s1on in measuring lek densities. of aerial and ground quadrat surveys 3. Document seasonal movement patterns of lesser prairie-chickens in relation to lek sites including lek-to-nest dispersal of hens and home range size of males and females. 4. Ascertain nest success of radio-marked hens in relation to vegetative cover at nest sites, and document timing and causes of nest failure. 5. Measure vegetative characteristics of lesser prairie-chicken occupied rangeland, leks sites, nest sites, brood-rearing sites, and feedingloafing sites. STUDY AREA Approximately 41.4 km2 (16 mi2) in and adjacent to pasture 1AE of the Comanche National Grasslands in eastern Baca County was selected as the primary study area for documenting habitat use, movements, and home range. This area was also used to examine the relationship between lek density, lek size, and male breeding density. Included were sections 21-28, and 33-36, T34S, R44W, and sections 1-4, T35S, R44W. Movements of radio-marked birds resulted in some vegetation sampling in adjacent pastures. Aerial surveys for leks were conducted on three areas in Baca County southwest of Campo (48 km2), southeast of Campo (46 km2), and east of Campo (40 km2). The latter area included most of the primary study area. Four roadside transects (17.6 - 22.5 km in length) to locate leks were in southeastern Baca County and adjacent to the primary study area and quadrats used in aerial surveys. The primary study area was comprised of approximately 90% rangeland and 10% dryland agriculture (fallow or grain sorghum). The U. S. Forest Service., Comanche National Grasslands managed the majority (72%) of the area with the remainder being privately owned (22%) or controlled by the State Board of Land Commissioners (6%). Livestock grazing was the predominate range use with cattle being present from May through November of each year. The habitat was characterized as sand sagebrush rangeland with mixed bunchgrasses dominated by sand dropseed (Sporobo1us cryptandrus), red threeawn (Aristida longiseta), and sideoats grama (Bouteloua curtipendula). Soapweed and broom snakeweed (Gutierrezia sarothrae) were common in some pastures. Dominant forbs included western ragweed (Ambrosia psilostachya) and Russian thistle (Salsola iberica). Plant nomenclature follows Harrington (1964). METHODS Lek Counts and Surveys Historic lek locations in Baca County were checked within 2 hours of sunrise from mid-February through May each year from 1986 to 1990 to document activity and obtain counts of males and females. Leks were defined as displaying aggregations of ~ 2 males (Martin and Knopf 1981), although lek sites with a history of activity were counted when only 1 male was regularly observed �11 displaying on the traditional arena. Leks on the study area were surveyed at least weekly in April and May and searches for additional leks conducted opportunistically·each year by listening from all accessible roads and trails in the area. Lesser prairie-chickens attending leks were classified to sex by display behavior and plumage characteristics. In a few instances when sex of birds could not be ascertained it was estimated that 90% of the birds on leks were males. The peak of hen attendance on leks was estimated from lek counts and trapping and summarized by 10-day intervals. The peak number of males at each lek within the study area was used to estimate male breeding density, as no radio-marked or leg-banded males were known to attend more than one lek. Lek density was calculated as the number of active leks within the 4l.4-km2 study area. Mean lek size was calculated as the peak number of males attending leks within the study area divided by the number of active leks. Information on numbers of leks and males on leks from· 1980 to 1985 was obtained from Colorado Division of Wildlife files and included for calculation of correlations between male breeding density and number of leks, and between male breeding density and average lek size. Lek surveys on the study area in these years were judged sufficient to locate all leks and count males on leks. Aerial surveys of the 3 quadrats were conducted using a Bell Soloy helicopter at 50-100 m elevation and flying parallel north-south transects separated by approximately 400 m (1/4 mi). Orange and white flagging was placed on fences (where available) to mark transects. Topographic features and a map also assisted the pilot and observer in· following transects. Flight speed was approximately 80 km/hr. The observer was naive to lek locations, at least during initial flights. One quadrat was surveyed each day between 0530 and 0730 on 14-16 April and again during 28-30 April 1987. Active leks were located prior to the initial survey by intensive searches on foot using a trained pointing dog and by listening for displaying birds with a parabolic microphone. Roadside transects were surveyed by personnel naive to lek locations on 14-15 April and 30 April-l May in 1987 and on 19-20 April 1988. Transects were initiated 30 minutes prior to sunrise and consisted of 3-minute stops every 0.8 km (1/2 mi) to listen for displaying lesser prairie-chickens. If birds were heard the compass direction to the source was drawn on a topographic map to estimate lek locations. In 1988 the observers retraced their routes after completion and attempted to visually locate lekking birds heard during the transect. The transects on 14-15 April 1987 and on 19-20 April 1988 were chosen to coincide with the peak of hen attendance on leks when display activity was most vigorous. Trapping. Banding. and Radio-tracking Lesser prairie-chickens were trapped using walk-in funnel traps connected with chicken-wire leads placed across leks (Toepfer et al. 1988) and with cannon nets set up near dominant males on leks. Usually 4-6 traps were placed on leks in 2 arrays surrounding activity centers and designed to intercept females moving across leks. The chicken-wire leads varied in length from < 4 m to > 10 m and connected adjacent traps. Traps were moved regularly in response to movements of males and females. The number of leks trapped varied with personnel available but was usually 4-6 each week during hen attendance. All but 2 active leks in the study area were trapped during one or more years of the study (1 lek was in a pasture used by cattle each spring, another lek �12 was active only during a short period in 1 year). Cannon nets were used occasionally on some leks in an attempt to capture more hens but the effort in setting up and moving nets in response to hen locations proved excessive. Persistent winds and rainfall were also detrimental to efforts in using the cannon nets. Captured birds were banded with a numbered aluminum band and a unique combination of 3 colored plastic bandettes. Age (adult or yearling) was ascertained from examination of distal primaries (Ammann 1944). Selected birds (2-3 males from each lek annually, most captured hens) were fitted with solar or battery-powered transmitters attached to ponchos (Amstrup 1980) (1986-90) or necklaces (1990). Solar transmitters weighed 22-26 gms and battery-powered transmitters weighed 13-20 gms (transmitters were 2.0-3.5% of the birds weight). Radio tracking was conducted on foot using Telonics TR-2 or Advanced Telemetry Systems (ATS) portable receivers and hand-held 3-element yagi antennas. Attempts were made to visually locate each bird weekly but this was not always attained during April and May when lek counts and trapping consumed most available time. Radio tracking usually lasted into AugustSeptember depending on survival of birds and battery life of transmitters. All locations were plotted on U. S. Geological Survey topographic maps (scale 1:24,000) and later recorded to the nearest 100 m as UTM coordinates. Home range sizes were calculated using the McPAAL software package (Stuwe and Blohowiak 1985) with 3 estimators; the minimum convex polygon (Mohr 1947), Koeppl et al.'s (1975) 95% ellipse, and Dixon and Chapman's (1980) harmonic mean. With the harmonic mean, a 10 x 10 grid was used with a 90% estimator. Individual·home ranges were calculated only for birds located a minimum of 10 times. Combined home ranges for all birds associated with individual leks were estimated using the minimum convex polygon and 95% ellipse, and calculated for 4 leks having at least 5 males and 5 (emales radio-marked. The combined home range for all birds associated with these leks was converted to a circular plot and a radius calculated for estimating the area around leks used by these birds. Vegetation Sampling Vegetation characteristics were measured at 10 randomly-selected transects in each cadastral section of the primary study area in April and May 1986-87 (8 sections/year) to ascertain vegetative composition and to measure residual cover. Along each 10-m transect, line-intercept of canopy cover (Canfield 1941) was recorded for all shrubs, grasses, forbs. and bare ground. Height of the nearest shrub, forb, tall grass, and short grass was measured every 2 m (6/transect). Sand sagebrush density was measured using 0.001 circular plots at the beginning, middle, and endpoint of each 10-m transect. Height-density readings (Robel et al. 1970) were obtained at 2-m intervals along the transect (6/transect). Vegetation was sampled at grouse use sites and nest sites by centering a lO-m transect along a north-south axis on the flush site (or nest site) and measuring vegetative parameters. For each grouse flush site a paired vegetation sample site was selected by randomly walking either north or south for a random distance of 1 to 400 m, and then randomly walking east or west for a random distance of 1 to 400 m. These paired (dependent) random sites were an attempt to measure vegetation characteristics within the flush radius �13· (home range) of lesser prairie-chickens. Selection for habitat variables was ascertained using the Wilcoxon signed rank test procedure for paired samples. Vegetative composition at lekking sites (arenas) was visually estimated to the nearest 5% and recorded in June after completion of male display and after vegetation was growing. RESULTS Lek Counts and Surveys Forty-two lesser prairie-chicken leks in southeastern Baca County were active for one or more years during 1986-90 (Table 1.) The number of leks counted each year ranged from 22 to 30. Thirteen leks were initially located during the study. Fourteen of 29 leks active in 1986 were occupied during aIlS years, and 8 leks were known to become inactive for 1 or more years. The proportion of males counted was 82.8% of the total high counts for all years combined and ranged from 79.9 to 86.1%. Female lek attendance patterns (Fig. 1) derived from 375 hens (range 49 - 114 annually) observed during daily lek surveys and trapping revealed a peak of attendance in early April in 1986 and in mid-April for 1987-90. I analyzed lek survey and lek count data collected from 1980 to 1990 on the 4l.4-km2 study area to ascertain relationships between male breeding density, average lek size, and lek density (Table 2). There was a strong correlation between male density and number of leks (~- 0.92, f - 0.0001) but not between male breeding density and average lek size (~- 0.15, f - 0.66). Correlations· using data from 1986 to 1990 showed similar patterns but were less significant (~- 0.85, f - 0.07; and ~ - 0.74, f - 0.15, respectively). Although lek density on the study area varied annually, there was little change in mean distance between neighboring leks. The mean distance to the nearest lek ranged from 1.24 to 1.44 km annually and from 0.96 to 2.28 km for individual leks. Aerial Quadrat Surveys Intensive ground searches resulted in detection of 15 lesser prairie-chicken leks on the 3 quadrats selected for aerial surveys (3, 3, and 9 leks, respectively). Numbers of males/lek ranged from 2 to 18 and averaged 6.7. During the initial helicopter flight during the peak of hen attendance 13 leks (86.7%) were detected. All leks were detected on the first 2 quadrats and 7 of 9 on the third quadrat (Table 3). When survey flights were repeated 2 weeks later, only 7 of 15 leks (46.7%) were detected with 3r 0, and 4 leks being detected on the 3 quadrats, respectively. Only 1 lek missed during the initial survey was detected during the second flight, but 7 leks detected initially were not observed during the second flight. �14 Numbers of lesser prairie-chickens counted, Baca County, Colorado, Table 1. 1986-90. Lek 2 3 4 5 6 7 12 14 15 17 18 23 25 27 28 30 31 33 35 36 37 38 39 40 41 42 43 44 ·46 86-1 86-2 86-3 87-1 87-2 87-3 87-4 87-5 88-1 88-2 88-3 90-1 90-2 1986 Males Totala 16 2 1 17 6 9 5 10 NC 4 10 2 2 0 12 1 2 7 10 1 12 2 11 8 3 10 5 0 1 15 6 7 19 3 1 19 8 10 5 10 NC 8 14 2 4 0 14 1 8 7 13 1 14 2 11 8 3 10 5 0 1 19 8 8 -- 236 . Totals 197 8.1 Avg./lek 6.8 1987 Males Total 9 3 3 18 3 8 4 8 NC 7 13 0 6 0 17 NC 9 8 18 2 18 7 6 9 0 10 NC 5 0 11 5 8 4 7 4 7 5 10 6 6 19 5 8 5 9 NC 9 15 0 6 0 24 NC 12 9 21 2 18 7 6 9 0 10 NC 8 0 14 6 8 4 7 4 9 5 242 281 8.1 9.4 1988 Males Total 12 11 6 23 6 12 2 6 NC 11 11 NC 5 7 20 NC NC 11 16 NC NC 0 7 -6 NC NC NC NC NC 12 0 6 3 9 NC 9 4 3 5 8 15 13 9 25 6· 16 4 13 NC 14 13 NC 8 7 25 NC NC 15+ 16 NC NC 0 14 6 NC NC NC NC NC 15 0 6 5 9 NC 14 4 3 6 8 231 289 8.9 11.1 1989 Males Total 13 9 0 21 7 16 3 5 17 11 11 0 6 3 15 NC NC 10 22 NC 11 0 0 13 NC 6 NC NC NC 10 0 11 0 9 NC 9 3 0 12 2 12 10 0 21 9 20 3 8 21 13 17 0 7 4 19 NC NC 14 25 NC 15 0 0 16 NC 9 NC NC NC 12 0 11 0 to NC 10 3 0 13 9 255 311 10.2 12.4 aIncludes males, females, and birds not classified to sex. 1990 Males Total 9 9 0 15 3 7 2 5 NC 4 5 NC 6 10 NC NC 2 NC NC NC 9 0 8 NC NC NC NC NC 7 0 0 0 8 NC 6 0 NC 6 8 5 5 11 12 0 17 4 9 2 9 NC 4 6 NC 7 5 13 NC NC 2 NC NC NC 9 0 10 NC NC NC NC NC 8 0 0 0 8 NC 6 0 NC 6 11 7 5 143 6.5 171 7.8 4 �15 100 C 1986 90 W > a: W en D 1987 80 ~ Dl 0 en 70 ~ _. W « ~ 60 1988 1989 1990 ~ W u, _. 50 0 40 u, 0 30 « I- l- IZ W 20 a: a. 10 0 UJ o MAR 1-10 APR 11-20 APR 21-30 APR MAY DATE Fig. 1. Timing of attendance of female lesser prairie-chickens in southeastern Colorado, 1986-90. on leks �16 Table 2. Lek count data for lesser prairie-chickens on the 4l.4-km2 study area, Baca County, Colorado, 1980-90. n n ~ Year Leks Males Ma1es/1ek 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 6 6 6 6 4 5 8 8 9 7 6 59 55 59 65 46 46 76 74 100 82 54 9.8 9.2 9.8 10.8 11.5 9.2 9.5 9.2 11.1 11.7 9.0 Ma1es/km2 1.42 1.33 1.42 1.57 1.11 1.11 1.84 1.79 2.42 1.98 1.30 Leks/km2 0.14 0.14 0.14 0.14 0.10 0.12 0.19, 0.19 0.22 0.17 0.14 Table 3. Lesser prairie-chicken leks detected during experimental helicopter surveys, Baca County, Colorado, 1987. Quadrat Quadrat size (km2) 47.9 46.0 40.1 1 2 '3 n Leks" 3 3 9 n Leks detected Flight Ib Flight 2c 3 3 7 3 0 4 aNumber of active leks within quadrat boundaries. b14-16 April. c28-30 April. Roadside Transects Roadside transects were evaluated along 4 transects by 2 observers in 1987 and along 2 transects by 2 observers in 1988. Overall, 59.3% of known active leks within 1.6 km (1 mi) of transects were detected (Table 4). In 1987 the observers detected 20.0 - 66.7%, with a higher proportion of leks being detected during the peak of hen attendance than 2 weeks later (62.5% vs 53.8%) under similar conditions. Observer bias was also documented with one obserVer detecting 63.2% of known leks and the 2nd observer detecting 46.7% of the known leks under similar weather conditions. In 1988, when all transects were covered during the peak of hen attendance, lek detection ranged from 76.9 to 100%. �17 Table 4. Leks detected during experimental County, Colorado, 1987-88. roadside transects in Baca n Leks detected Observer Surve:;l Transect Year Length(km) 1 2 1987 1987 1987 1987 1988 1988 -17.6 22.5 19.2 19.2 19.2 19.2 3 4 5 6 n 3 7 11 5 1 2 1 2 2 1b 1b 1 3 2 1 1 1 7 6 4 10 4 6 4 3 3 12 4 13 4 1.6 km of transects. aNumber of known active leks within "winds > 30 km/hr. Trapping Leks'' and Banding One hundred and forty-nine lesser prairie-chickens (75 males, 74 -females) from 10 leks on or adjacent to the study area were trapped and banded from 1986 to 1990 (Table 5). Most (n - 126, 84.6%) were trapped from 4 leks on the study area which were occupied aIlS years. In addition there was 1 trap mortality (heat stress), and 11 recaptures (all males) of birds trapped earlier within the year (n - 7) or from previous years (n - 4). Locations of male and female lesser prairie-chickens Table 5. Baca County, Colorado, 1986-90. trapped in F Totals M F Year 1987 1986 1988 Lek M F M F 2 3 4 5 18 28 8 5 3 1 6 6 2 4 2 4 Totals 3 1 2 3 4 3 7 1 2 6 4 4 3 5 1 2 4 4 1 4 5 5 M 13 17 M 14 3 3 3 3 12 3 9 19 19 3 24 2 14 14 4 1 4 19 1990 F F 33 86-1 86-2 87-4 1989 M 2 14 15 6 18 . 75 6 4 2 32 13 1 9 1 6 74 �18 Movements and Home Range Lek to nest distances were calculated for lek-of-capture and nearest lek-tonest for all radio-marked hens for which nests were located (n - 31). The mean distance from lek-of-capture to nest site was 1.80 ± 1.04 km (range 0.22 - 4.85 km) and farther (f - 0.0009) than the mean distance from the nest site to the nearest lek (1.04 ± 0.60 km, range 0.22 - 2.50 km). Radio transmitters were placed on 108 lesser prairie-chickens (37 males, 71 females) from 1986 to 1990 to facilitate location for estimation of movements and home range. Transmitter loss or failure, dispersal from the area, and high mortality from depredation resulted in loss of data from 75 birds within 2 months. The remaining 33 birds (19 males, 14 hens) provided an adequate sample of relocations for estimates of summer home range (Table 6). Because of unequal variances, non-parametric Wilcoxon tests were used to compare home range size between sexes. Home range size estimated using the minimum convex polygon did not appear to be affected by sample size for males (~ - 0.13, f 0.60) or females (~- -0.14, f - 0.63). Average home range'size of females (5.96 ± 8.18 km2) was larger (f - 0.03) than average home range size of males (2.11 ± 1.54). Home range estimates using the 95% ellipse also suggested females had larger (f - 0.009) home ranges than males (28.52 vs. 8.53 km2). The Harmonic Mean estimate of home range did not detect a significant difference between sexes (f - 0.07) although the trend.was for females to have larger home ranges (4.12 vs 2.30 km2). . . A combined home range estimate for all prairie-chickens associated w~th individual leks was calculated using the minimum convex polygon and the 95% ellipse. This "lek home range" estimated the minimum habitat used by a population of lesser prairie-chickens associated with individual leks. Four of 10 leks from which I trapped lesser prairie-chickens had a sufficient sample of home ranges from both males and females (Table 7). The average home range size (minimum convex polygon) was 46.30 ± 12.69 km2 while that calculated using the 95% ellipse averaged 34.67 ± 12.78 km2. If a circular range around leks is assumed, these values represent a radius around leks of 3.84 km and 3.32 km, respectively. Habitat Characteristics 'Study area Cursory measurements of vegetation in April and May, 1986-87 indicated a diversity of vegetative structure and species composition among and within the pastures which comprised the primary study area (Table 8). Height and canopy cover of residual grass varied widely with grass height being weakly correlated to height-density (~- 0.44, f - 0.08). Grass cover averaged 19.9% and bare ground accounted for 75.7% of the basal area. Forb cover (4.4%) was low because many of the annual forbs had not begun their growth when transects were measured. Sand sagebrush averaged 3.1% canopy cover with a mean density of 2,497 plantsfha. �19 Table 6. Home range estimates of lesser prairie-chickens in Baca County, Colorado, 1986-90. Band Mean 306 308 315 317 318 319 324 327 335 344 349 351 356 362 366 373 403 404 405. 406 408 411 418 423 424 425 426 427 432 438 442 446 447 Year Sex Lek 1986 1986 1986 1986 1986 1986 1986 1986 1987 1987 1987 1987 1987 1988 1988 1988 1989 1989 1989 1989 1989 1989 1989 1989 1989 1989 1989 1990 1990 1990 1990 1990 1990 M M 86-1 5 5 2 5 5 86-2 28 2 28 5 28 5 4 86-1 4 86-1 86-1 ·87-4 86-1 5 86-1 86-1 2 2 28 2 28 28 5 28 3 3 F F M F M F M F F M M M M F M F F M M F M M M M M M F F M F F Horne range size estimate (krn2) Min. Convex Polygon 95% ellipse 90% Harmonic 1.16 2.07 5.67 32.32 2.44 12.70 1.04 2.26 2.25 3,45 2.32 3.95 6.77 2.65 1.55 4.45 1.69 2.30 5.83 1.36 0.08 5.24 3.17 0.94 0.55 0.66 1.24 3.77 4.12 0.23 2.72 1.52 1.01 7.61 4.93 22.27 199.12 8.34 45.89 3.21 9.68 11.65 10.47 10.28 15.11 39.38 8.40 5.34 15.62 6.42 11.24 29.70 6.08 0.39 19.08 13.22 4.00 2.94 2.32 6.36 9.13 12.29 1.01 7.43 7.68 4.96 1.03 1.68 6.65 10.79 4.34 8.64 1.33 1.49 2.45 4.14 2.08 3.11 3.94 3.44 2.07 4.11 2.53 1.67 2.80 2.75 0.07 5.60 3.04 1.32 0.63 1.06 0.63 5.19 3.70 0.43 3.10 1.02 4.52 �20 Combined home range estimates (lan2) of lesser prairie-chickens Table 7. Baca County, Colorado, 1986-90. n Birds in Home range estimator Observations MCP 95% ellipse 90% HM Lek 2 Males Females Totals 8 5 13 68 24 92 5.30 51.30 51.30 6.51 163.27 51.30 4.87 22.24 33.35 Lek 5 Males Females Totals 10 23 33 88 123 211 14.59 58.03 61.92 11.46 56.08 38.09 9.12 28.25 31.38 Lek 28 Males Females Totals 9 11 20 77 69 146 15.88 29.30 25.28 11.53 40.01 24.75 6.76 24.65 19.66 Lek 86-1 Males Females Totals 8 6 14 77 37 114 16.11 21.60 36.69 16.47 28.92 24.52 8.82 .17.71 21.57. Lek sites Vegetative composition was, measured at 9 active leks on and adjacent to the primary study area (Table 9). Shrubs, including sand sagebrush were relatively scarce, and comprised approximately 10% of the cover. Short grasses were relatively common, and taller grasses were usually grazed to a low height. �Table 8. Habitat characteristics of the 41.4-km2 lesser prairie-chicken study area, Baca County, Co Lo r ado", Height (em) Sand sagebrush Canopy Density cover (X) Shrub Forb Grass Heightdensity Sec.21,T34S,R44W Sec.22,T34S,R44W Sec.23,T34S,R44W Sec.24,T34S,R44W Sec.25,T34S,R44W Sec.26,T34S,R44W Sec.27,T34S,R44W Sec.28,T34S,R44W Sec.33,T34S,R44W Sec.34,T34S,R44W Sec.35,T34S,R44W Sec.36,T34S,R44W Sec.i,T35S,R44W Sec.2,T35S,R44W Sec.3,T35S,R44W S·ec.4,T35S, R44W 40.5 44.6 40.0 33.6 31.5 31.0 29.2 29.8 35.5 36.6 32.2 33.8 28.1 31.1 42.9 32.8 3.3 3.8 3.6 3.1 4.6 4.5 1.5 1.7 3.2 4.7 4.0 1.9 2.0 4.4 3.6 6.0 6.0 27.1 22.5 16.9 13.9 17.2 6.6 7.4 11.0 15.5 12.0 4.4 9.7 9.9 17.4 11.2 0.28 0.90 1.16 1.46 0.87 1.58 0.32 0.79 1.67 1.18 0.97 0.78 1.33 0.57 1.07 0.78 0 2,360 4,160 7,480 . 2,467 2,840 2,067 4,266 2,800 1,560 2,880 533 667 1,520 1,267 3,080 Average 34.6 3.5 13.0 0.98 2,497 Location Bare ground Forbs Grass 0.0 7.1 10.0 5.4 3.1 4.6 0.6 3.0 5.1 2.6 3.5 0.2 0.1 0.9 1.9 1.5 81. 2 62.4 65.6 77 .1 86.1 70.4 55.2 84.5 81.9 72.3 77 .8 79.8 89.8 74.7 73.4 78.4 0.9 8.4 11.6 11.5 5.6 11.0 1.4 5.5 1.4 2.3 2.8 1.3 2.9 1.7 1.3 1.1 18.0 29.1 22.7 11.5 8.9 18.6 43.6 10.0 16.7 24.0 19.5 18.9 7.3 23.4 25.3 20.5 3.1 75.7 4.4 19.9 aVegetation measured in April-May, 1986-87. N I-' �22 Table 9. Vegetative characteristics at lesser prairie-chicken leks in Baca County, Colorado. Lek Sand sagebrush DensityC ~ hgt. (cm) 2 3 4 5 27 28 86-1 86-2 87-4 0 889' 0 111 111 0 1,556 111 111 Avg. 310 Buda Bogr n/a 37.4 n/a 37.0 47.0 n/a 27.3 31.0 64.0 45 10 25 30 50 20 10 65 40.6 20.0 Vegetative com:Qositiona,b Bocu Spcr Sihy Arlo FoSh 25 20 20 5 5 75 10 50 5 5 10 5 10 5 5 5 10 5 5 40 40 7.2 16.7 55 40 5 90 19.4 15.6 10.5 apercent of vegetative cover bBuda - Buch10a dacty1oides, Bogr - Boute1oua gracilis, Bocu - ~. curte:Qendula, Spcr - Sporobo1us cIYPtandrus, Sihy - Sitanion hystrix, Aristida longiseta, FoSh - forbs and shrubs. CP1ants/ha 10 10 5 15 15 5 15 10 10 10.6 Ar1o- Nest sites Vegetative characteristics were measured at 29 nest sites from 1986 to 1990. All but 2 nests were located following radio-marked hens. Measurements reflect site characteristics after hatch or nest loss as I attempted to minimize disturbance to nests during egg laying or incubation. Most nests (n - 20, 69.0%) were adjacent to shrubs, primarily sand sagebrush (n - 12, 41.4%) and soapweed (H - 6, 20.7%), with the remainder being within clumps of bunchgrasses. The tallest vegetation over nest bowls averaged 50.7 ± 14.7 cm (range 29-81 cm). Nests were typically in sites having greater (f < 0.001) height of shrubs, forbs, and grasses and higher height-density readings than areas immediately adjacent to them (Table 10). Vegetative cover was relatively sparse with a line intercept average of 69.5% bare ground, 29.4% grasses, and 1.4% forbs. Density and canopy cover of sand sagebrush varied with the site and averaged 3,410 shrubs/ha and 7.2% canopy cover. Feeding-loafing sites Vegetation at lesser prairie-chicken flush sites and paired dependent sites were analyzed separately for males and females for each month data were collected (May - Sep). Dependent sites averaged 280.5 ± 109.5 m (range 55 541 m) from flush sites and were measured the same day as corresponding flush sites. �23 Vegetative Table 10. Baca County, Colorado, cm Height-density, Nest Transect density Canopy cover, % Sandsage Grasses FQrbs Bare ground, % SD Range 47.6 37.6 14.9 9.7 29 2.7 - 81 57.2 21.2 15.7 11.0 5.8 5 6.3 - 54 24.7 36.1 27.4 15.0 12.5 9 9.3 - 60 59.0 3.2 2.0 1.5 0.7 1.0 1.0 - - 6.5 3.4 0 - 12,667 26a cm Grass height, Nest Transect ~ nest sites in 26a cm Shrub height, Nest Transect Sandsage at lesser prairie-chicken n Characteristic Forb height, Nest Transect characteristics 1986-90. 29 dm 29 29 3471 3439 29 29 aShrubs and forbs were not present 7.2 29.4 1.4 9.4 14.9 1.5 0 9.3 0 - 36.1 61. 8 6.5 69.5 14.3 38.2 - 87.7 along 4 nest transects. When comparing heights of shrubs, forbs, and grasses, and height density at flush sites of male lesser prairie-chickens with the dependent site for each month, shrub height, grass height, and height-density were greater (f < 0.05) at flush sites than at dependent sites in July only (Table 11). No differences were detected in sandsage density or canopy cover between male flush sites and dependent sites (Table 12) within any month. There were no differences in percent bare ground or canopy cover of grass or forbs between flush sites and dependent sites within any month (Table 13). Vegetative parameters measured at flush sites of female lesser prairiechickens were similar to those at dependent sites. No differences were detected in heights of shrubs, forbs, or grasses within any month and heightdensity was greater (f < 0.05) at flush sites only in July (Table 14). No differences in sandsage density or canopy cover were detected between flush sites and dependent sites within any month (Table 15). There was no difference detected in percent bare ground or canopy cover of grass or forbs between f1ush.sites and dependent sites within any month (Table 16). �24 Table 11. Shrub, forb, and grass height (cm) and height-density (dm) at flush sites and dependent sites of male lesser prairie-chickens in southeastern Colorado, 1986-90. May Jun SD Shrub height FSa DSb Jul SD Aug SD Sep SD SD 35.8 34.3 14.2 8.9 37.2 36.6 13.7 9.5 46.9 40.3 8.3C 41.0 11.1 8.6 34.3 18.5 Forb height FS DS 9.2 7.9 2.6 1.7 9.6 8.7 2.7 3.8 23.7 21.2 6.0 8.0 23.9 20.7 7.7 11. 5 29.6 26.6 24.6 10.0 Grass height FS DS 11.0 10.0 2.5 1.9 10.2 10.3 2.5 3.0 27.8 20.2 7.9C 4.5 28.4 27.9 8.5 15.3 23.4 18.9 0.6 26.7 Height-Density 1.25 FS 1.13 DS 0.73 0.83 2.01 1. 96 0.87 0.67 2.17 1.44 0.55C 0.56 2.04 1.24 1. 50 1. 75 1. 30 0.92 0.71 1.05 33.6 11.7 29.8 18.4 aF1ush site. bDependent site . .CSignificant (f < 0.05) difference between flush site and dependent site. Table 12. Sandsage density (plants(ha) and canopy cover at flush sites and dependent sites of male lesser prairie-chickens in southeastern Colorado, 1986-90. Month Flush site SD ~ May Jun Ju1 Aug Sep 2970 4077 3111 3905 1834 2558 3873 34i2 2242 2595 Densit::i Dependent site SD ~ 3303 5205 1444 3000 500 1946 4198 1951 2465 707 Gano~::icover {%) Flush site Dependent site SD SD ~ ~ 4.0 6.4 5.6 9.7 0.0 4.8 9.6 5.2 9.4 4.1 6.3 1.7 9.1 3.2 5.6 6.8 2.3 12.7 4.5 �25 Table 13. Bare ground (%) and canopy cover (%) of grasses and forbs at flush sites and dependent sites of male lesser prairie-chickens in southeastern Colorado, 1986-90. Cano12:£cover (X) Month May Jun Jul Aug Sep Bare ground (X) DS6 FSa SD SD ~ ~ 86.5 90.4 56.3 72.6 46.3 14.6 5.1 22.3 15.5 29.4 89.9 91.0 59.8 57.4 41. 7 Forbs Grass FS 8.5 5.4 21.5 25.4 21.1 DS FS ~ SD ~ SD ~ 10.7 7.9 42.7 26.5 53.7 14.9 5.8 23.3 15.7 29.4 8.3 7.4 39.4 42.2 58.0 8.7 6.0 21.8 25.7 21.5 1.3 1.8 0.9 0.8 0.0 DS SD 1.2 2.0 1.0 1.7 SD ~ 1.0 1.7 0.8 0.5 0.2 1.1 1.5 0.7 0.4 0.3 aF1ush site. bDependent site. Table 14. Shrub, forb, and grass height (cm) and height-density flush sites and dependent sites of female lesser prairie-chickens southeastern Colorado, 1986-90. May Jul Jun ~ SD 13.2 7.5 35.2 33.7 13.6 10.7 11.7 5.0 Grass height FS 17.6 DS 12.5 11.9 7.9 SD Shrub height 42.8 FSa DSb 37.2 Forb height FS DS ~ Height-density 2.49 FS 1.09 DS 1.01 0.50 ~ SD ~ SD 14.8 16.5 41.0 41.1 7.9 18.7 37.0 36.3 10.6 21.5 19.8 20.7 5.5 6.6 22.5 22.5 7.7 7.7 21.2 23.0 9.1 10.5 23.5 21.4 8.6 8.6 25.9 27.0 7.6 10.7 28.2 29.3 11.6 5.9 ~ 10.3 13.2 40.9 35.8 14.3 11.6 3.8 3.9 12.3 12.2 6.4 3.9 1.22 1.54 Sep Aug SD 2.15 1.56 (dm) of in 2.03 1.74 0.8F 0.74 1.25 0.47 1.32 0.38 1.33 1.52 1.52 1.18 aF1ush site. bDependent site. CSignificant difference (f < 0.05) between flush site and dependent site. �26 Table IS. Sand sagebrush density (p lant.syha) and canopy cover at.flush sites and dependent sites of female lesser prairie-chickens in southeastern Colorado, 1986-90. Month Sand sagebrush densit~ Flush site Dependent site SD SD ~ ~ Cano:Q~ cover (%} Flush site Dependent site SD SD ~ ~ May Jun Jul Aug Sep 5778 6857 5000 2833 6334 12.2 11.4 13.0 4.0 11.8 6883 4857 3957 3590 6471 3000 5667 3030 2916 2000 3283 3991 3497 3458 1660 8.3 13.9 13.5 7.4 11.0 2.2 5.8 6.7 4.1 2.1 2.0 6.8 10.0 5.8 3.9 Table 16. Bare ground and canopy cover of grasses and·forbs at flush sites and dependent sites of female lesser prairie-chickens in southeastern Colorado, 1986-90. Month May Jun Jul Aug Sep s 88.8 85.6 73.7 69.1 68.2 Bare ground ~Xl b FS8 OS SO SO .& 5.6 7.4 16.4 15.9 23.7 78.5 88.6 68.5 66.3 64.7 15.1 8.2 20.0 20.4 24.2 Canoex cover ~*l Grass FS OS SO SO .& .& 9.9 12.0 24.8 30.1 31.2 5.9 8.8 17.2 16.5 23.7 19.4 9.5 30.4 32.4 35.0 16.3 8.6 21.0 21.6 24.0 Forbs s 1.3 2.4 1.5 0.8 0.6 FS OS SO 0.5 2.0 1.3 0.9 0.5 .& 2.0 2.5 1.2 1.2 0.3 SO 0.5 2.1 1.3 1.4 0.3 aFlush site. boependent ·s.i te~ DISCUSSION Lek counts and Surveys Counts of male lesser prairie-chickens on leks have been used to estimate population size or monitor population changes (Davison 1940, Copelin 1963, Hoffman 1963, Jones 1963, Crawford 1974, Crawford and Bolen 1976). An implicit assumption in using lek counts for population estimates is that either all males or at least a constant portion of the male population attend arenas each year and that changes in counts are correlated to actual population changes. Studies of black grouse (Lyrurus tetrix) (Robel 1969) and sharp-tailed grouse (TyID:Qanuchus:Qhasianellus) (Rippin and Boag 1974) suggest that less than onehalf of the male population may attend a lek on any given day, and that for sharp-tailed grouse, there is a segment of the adult male population which fails to become territorial in spring (Moyles and Boag 1981). Beck and Braun (1980) observed that there was no proven relationship between counts of males �27 sharp-tailed grouse, there is a segment of the adult male population which fails to become territorial in spring (Moy1es and Boag 1981). Beck and Braun (1980) observed that there was no proven relationship between counts of males on leks and sage grouse (Centrocercus urophasianus) populations. Despite these shortcomings, 1ek counts continue to be used as a management tool for population estimates of sage grouse (Patterson 1952, Stanton 1958, Dalke et a1. 1963, Eng 1963, Hartzler 1972, Jenni and Hartzler 1978, Rothenmaier 1979, Beck and Braun 1980), greater prairie-chickens (Tympanuchus cupido) (Ammann 1957, Robel 1970, Westemeier 1971, Hamerstrom and Hamerstrom 1973, Kirsch et a1. 1973) and sharp-tai1ed,grouse (Ammann 1957, Kobriger 1965, Pepper 1972, Hillman and Jackson 1973, Kirsch et a1. 1973, Yde 1977, Mattise 1978, Nielson 1978, Ziegler 1979). In recent years there have been efforts to count pra1r1e grouse leks instead of individual males on leks as an index to annual fluctuations in population size (Cannon and Knopf 1981, Martin and Knopf 1981). Some states have traditional "booming ground" routes they survey each year to detect changes in number of leks (Horak 1985). Because these routes were not randomly selected, population inferences could not be made to areas other than the routes. The value of this technique assumes a high degree of precision (repeatability) if not accuracy, and little or no observer bias. This study indicated both poor precision and accuracy as well as individual differences among observers, even under similar weather conditions. '. Aerial transects appeared to give accurate estimates of lek density when flown during the peak of hen attendance, probably because the aircraft caused hens to f1ush'where they were more easily detected. The number of males attending leks several ·weeks later was similar but less than half the 'leks were· detected, presumably because males were less active and less likely to flush. Too few flights were made to estimate the precision of this technique, and because of the high cost, it cannot be recommended as a standard management practice. However, it does have the advantage in surveying large areas quickly and will likely provide information on distribution of prairiechickens if conducted during the peak of hen attendance. Data from lek counts and intensive and extensive lek surveys in Baca County suggest that populations of lesser prairie-chickens increased from 1986 to 1990, and'were likely increasing since at least 1980. More leks were located both on and adjacent to the study area and some historic leks which had been inactive previously became active for one or more years. Since lek activity and 1ek locations have changed annually, the best method for documenting incremental changes in prairie chicken population remains intensive ground surveys. Survey procedures should incorporate monitoring of leks active in the previous year, surveys of,historic and abandoned lek sites, and listening routes to detect newly established leks. Trapping and banding Walk-in funnel traps were relatively effective for capturing lesser pra1r1echickens on leks. Trapping success for males was highest during the initial trapping period before they became habituated to traps and altered territory boundaries with respect to traps and chicken-wire leads. Moving traps to different locations on leks resulted in additional males being trapped. Capturing hens was most successful when wire leads bisected leks and caused �28 hens to enter traps as they moved across leks. When several hens were on a lek at the same time they often moved as a flock, although aggression was commonly observed. The chasing of hens by males often resulted in captures of both males and females. Multiple captures of females was more common than multiple captures of males. More than one male in a trap resulted in constant fighting and injury (scrapes to head and wings) to the subordinate bird, unless they were removed quickly. In contrast, when> 1 hen was in the same trap there was little aggression and few injuries, thus they could be left in traps longer. Most birds (n - 139, 93.3%) were trapped during April when hens visited leks and male display activity was highest. During May, few hen were observed on leks and male activity declined in intensity and duration, and few males were captured. Movements to Nest Sites Mean distances moved by radio-marked hens from lek-of-capture to nest sites has ranged from 1.2 km for 8 hens in Texas (Sell 1979) to 3.4 km for 37 hens in New Mexico, with individual hens moving up to 14 km (Davis "et al. 1979). Distances moved from leks to nests and hen home ranges might be attributed to habitat characteristics or weather, with shorter movements and smaller home ranges in better quality habitats and during seasons of average or above rainfall (Sell 1979, Merchant 1982). There was no indication that radio packages affected movements of birds. Other studies of nesting lesser prairie-chickens (Copelin 1963, Donaldson 1969, Haukos 1988) failed to mention movements of hens to nests or distances from nearest leks to nests. Identification of nesting habitat based on movements between lek-of-capture and nest site may be misleading if hens visit several leks before mating as shown for greater prairie-chickens (Schroeder 1990)~ Although no radio-marked hen was known to visit other leks, such movements could have easily occurred without my knowledge or occurred prior to being marked. Since the inter-lek distance in this study (1.32 km) was less than the distance from lek-ofcapture to nest site (1.80 km) it is likely that hens visited> 1 lek or traveled past other leks during the breeding season. Movement of hens from leks to nests and lek-nest distances have implications for identifying critical nesting and brood-rearing habitats. If females tend to cluster nests around leks, or if leks are focal to female home ranges (Bradbury 1981), then nesting areas can be protected from disturbance or enhanced through management without documenting nesting preferences for each population. Furthermore, leks are easier to locate than nests, especially when nests are widely dispersed, well camouflaged, and occur at low densities. Home Range Although home range is defined as the area used by an individual during its normal activities (Burt 194~), home range size has proven difficult to quantify or estimate. The minimum convex polygon (Mohr 1947) is the oldest and most common estimate of home range size but is a function of the number of observations used in the estimate (Boulanger and White 1990). By eliminating individual birds having < 10 locations I was able to minimize this error and correlations between home range size and number of locations were not significant for either males or females. �29 Males had smaller summer home ranges than hens (all 3 home range estimators) which may reflect their attachment to leks in spring and fall and the importance of maintaining territories on leks to assure a chance of mating during the breeding season. Home ranges of males often overlapped and radiomarked males were often observed with other birds (presumed males) during summer. This association among males may be important for maintaining dominance relationships among males attending the same lek. The value of larger home ranges to hens is unknown but may be related to nesting and rearing young. Too few radio-marked hens were successful in nesting to test for differences in home range size between hens with and without broods. Vegetation on the Study Site The diversity of vegetative structure and species composition reflects different soil and topographic conditions as well as differences in past use and revegetation efforts. Draws were typically vegetated with sand sagebrush and a diversity of annual forbs (many of which hadn't begun growth when transects were measured). Individual cadastral sections were dominated by different grass species, usually sand dropseed or sideoats grama, which reflected previous revegetation efforts by the U. S. Forest Service. Height of residual grasses and height density were influenced by livestock grazing the previous season, especially grazing from October to December when grasses were dormant. The amount of bare ground was attributed to lack of soil moisture which reflected low annual rainfall, high summer ambient temperatures and evaporation, and sandy soils which retained subsurface moisture poorly. Lek Habitat The use of habitats with short vegetation for lekking activity of lesser prairie-chickens has been well documented (Copelin 1963, Jones 1963, Crawford and Bolen 1973, Davis et al. 1979). The advantage to sites with high visibility inclu~e enhancement of visual displays for territorial defense as well as for attracting hens (Kermott and Oring 1974, Sparling 1981). Also, open habitats allow better detection of predators which may be attracted to displaying grouse (Hamerstrom et al. 1965, Anderson 1969). Nesting Habitat Preferred nest sites of lesser prairie-chickens usually occur where height of residual cover is greatest «Copelin 1963, Haukos 1988) or in ungrazed or lightly grazed rangeland (Davis et al. 1979). Height of vegetation above nest bowls usually exceeded 50 cm (Donaldson 1969, Suminski 1977, Riley 1978) and was similar regardless of plant height (shrub or grass). In areas where livestock grazing was heavy, hens tended to nest under shrubs (Davis et al. 1979, Sell 1979, Wisdom 1980, Merchant 1982) even though nests under shrubs tended to be less successful than nests under bunchgrasses (Sell 1979). Furthermore, regardless of habitat type, height and density of vegetation at successful nests were greater that at unsuccessful nests (Davis et al. 1979). Because of these relationships, nesting success was inversely related to grazing pressure. Grazing has previously been implicated in causing declines of lesser prairie-chickens (Jackson and DeArment 1963). �30 Feeding-Loafing Sites With few exceptions, both male and female lesser prairie-chickens used habitats that were similar to those at dependent sites. Since dependent sites were within flight distance of the grouse (avg. - 280.5 m), any differences in habitat variables would have indicated possible habitat selection. Few studies addressed summer habitat preferences of lesser prairie-chickens in sand sagebrush habitats, primarily because most occupied ranges are characterized as shinnery oak (Quercus havardii)" grasslands. Summer habitat use by lesser prairie-chickens within sand sagebrush rangelands showed higher relative use of shrubby cover to grassy cover by broods and flocks of males (Riley 1978, Davis et a1. 1979, Cannon 1980). This is thought to reflect the higher abundance of insect food in shrub and forb substrates compared to grass (Davis et al. 1980). Insects comprise a large portion of the summer diet of lesser prairie-chickens (Jones 1964, Davis et a1. 1980) and may be more visible or accessible in shrub and grass habitats. Shrub and forb dominated habitats may also have more bare ground which may facilitate movement by young broods when foraging. Microclimate may also be a factor in selection of shrubby habitats as lesser prairie-chickens are known to seek shade during hot weather (Copelin 1963) and sand sagebrush may provide more shade than grass. This may be critical when livestock grazing results in reduction of grass height but has little impact on shrub height or structure. The lack of selection of habitat structure by lesser prairie-chickens documented in this study may be. the result of relatively uniform habitat conditions on the study area compared to other rangeland. The study area was selected on the basis of reported high densities of lesser prairie-chickens which suggests that habitat conditions were generally favorable. Furthermore, the U.S. Forest Service has managed pasture lAE for wildlife values including lesser prairie-chickens which resulted in less use of forage in that pasture by livestock than on adjacent rangelands. In more marginal habitat, selection may have been easier to detect. 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T. 1985. 25 May, 1985. pp. Survey of the lesser prairie-chicken in Colorado, 3 AprilUnpubl. rep. Colorado Div. Wildl., Colorado Springs. 22 Riley, T. Z. 1978. Nesting and brood-rearing habitat of lesser pra~r~e chickens in southeastern New Mexico. M.S. Thesis, New Mexico State Univ., Las Cruces. 59 pp. Rippin, A. B., and D. A. Boag. 1974. Recruitment to populations of male sharp-tailed grouse. J. Wild1. Manage'. 38:616-621. Robel, R. J. 1969. Movements and flock stratification within a population of blackcocks in Scotland. J. Anim. Ecol. 38:755-763. 1970. Possible role of behavior in regulating greater prairiechicken populations. J. Wildl. Manage. 34:306-312. ______ , J. N. Briggs, J. J. Cebula, A. D. Dayton, and L. C. Hulbert. 1970. Relationships between visual obstruction measurements and weight of grassland vegetation. J. Range Manage. 23:295-297. Rothenmaier, D. 1979. Sage grouse reproductive ecology: breeding season movements, strutting ground attendance and site characteristics, and nesting. M.S. Thesis, Univ. Wyoming, Laramie. 97 pp. Sands, J. L. 1978. Game bird studies'. New Mexico Dep. Game and Fish. Fed. Aid Proj. W-l04-R-19. Sante Fe. 5 pp. Schroeder, M. A. 1990. Movement and dispersion of greater prairie-chickens in northeastern Colorado. Ph.D. Diss., Colorado State Univ., Fort Collins. 135 pp. Sell, D. L. 1979. Spring and summer movements and habitat use by lesser pra~r~e chicken females in Yoakum County, Texas .. M.S. Thesis, Texas Tech. Univ., Lubbock. 42 pp. �35 Sparling, D. W. 1981. Communication in pra~r~e grouse. I. Information content and intraspecific functions of principal vocalizations. Behav. Neuro~. BioI. 32:463-486. Stanton, D. C. 1958. A study of breeding and reproduction in a sage grouse population in southeastern Idaho. M.S. Thesis, Univ. Idaho, Moscow. 87 pp. Stuwe, M., and C. E. Blohowiak. 1985. McPAAL software package for calculating home ranges. Conserv. Res. Cent., Natl. Zool. Park, Smithsonian Inst., Front Royal, VA. Suminski, H. R. 1977. Habitat evaluation for lesser prairie-chickens in eastern Chaves County, New Mexico. M.S ..Thesis, New Mexico State Univ. , Las Cruces. 49 pp. Taylor, M. A., and F. S. Guthery. 1980. Fall-winter movements, ranges and habitat use of lesser prairie-chickens. J. Wildl. Manage. 44:521-524. Toepfer, J. E., J. A. Newell, and J. Monarch. 1988. A method for trapping prairie grouse hens on display grounds. Pages 21-23 in A. D. Bjugstad, Tech. Coord. Prairie chickens on the Sheyenne National Grasslands. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. RM-159. Westemeier, R. L. 1971. The history and ecology of pra~r~e chickens in central wisconsin. Univ. Wisconsin, Res. bull. 281. 66 pp. Wilson, D. L. 1987. Nesting habitat of lesser prairie chickens in Roosevelt and Lea counties, New Mexico. M.S. Thesis, New Mexico State Univ., Las Cruces. 36 pp. Wisdom, M. J. 1980. Nesting habitat of lesser pra~r~e chickens in eastern New Mexico. M.S. Thesis, New Mexico State Univ., Las Cruces. 38 pp. Yde, C. A. 1977. Effects of rest-rotation grazing on the abundance and distribution of sharp-tailed grouse. M.S. Thesis, Montana State Univ., Bozeman. 70 pp. Ziegler, D. L. 1979. Distribution and status of the Columbian sharp-tailed grouse in eastern Washington. Upland Game Invest., Washington Dep. Game Fed. Aid. Wildl. Rest. Compl. Rep. Proj. W-70-R-18. 26 pp. Prepared by Kenneth M. Giesen Wildlife Researcher C ��37 JOB FINAL REPORT Colorado State of: Project: W-152-R Work Plan: Job Title: 12 Job _l2g_ Chronology of Breeding and Nesting Activities Relation to Timing of Spring Hunting Seasons Period Covered: Author: Upland Bird Research of Wild Turkeys in 01 July 1985 through 30 June 1991 Richard W. Hoffman Personnel: T. D. Abell, J. L. Aragon, C. E. Braun, R. W. Hoffman, R. L. Holder, B. S. Linkhart, T. B. Lundt, R. K. Mueckler, and T. J. Spezze, Colorado Division of Wildlife ABSTRACT An interim final report was prepared ~n 1989-90. The following manuscripts incorporating data presented in this report were prepared or published in 1990-91: Hoffman, R. W. 1990. Chronology of gobbling and nesting activities Merriam's wild turkeys. Natl. Wild Turkey Symp. 6:25-31. of 1991. Spring movements, roosting activities, and home range characteristics of male Merriam's wild turkeys. Southwest. Nat. press) . Schmutz, J. A., and R. W. Hoffman. 1991. Variable first prebasic molt in Rio Grande and Merriam's wild turkeys. Wilson Bull. 300. primary 103:295- Western States Wild Turkey Commi,ttee. 1991. Management guidelines for Merriam's wild turkeys. Natl. Wild Turkey Fed., Edgefield, South Carolina. 55pp. (Submitted for review). Prepared by Mtv IItL,..___--: Richard W. Hoffman Wildlife Researcher C 36: (in ��39 JOB FINAL REPORT State of: Colorado Project: Work W-ls2-R Plan: Job Title: Period Author: 14 Upland : Job _3_ Seasonal Covered: Michael Bird Research Movement 01 January and Habitat 1986 through Use by Greater 30 June Prairie-Chickens 1991 A. Schroeder Personnel: M. A. Schroeder and G. C. White, Colorado State University; C. E. Braun, J. F. Corey, F. M. Pusateri, M. E. Rasmussen, and L. A. Robb, Colorado Division of Wildlife ABSTRACT Several hypotheses have been proposed to explain the evolution of clumped (lek mating) from dispersed (territorial mating) polygyny; most recent models suggest that increased female home range size leads to increased female choice for males and/or leks. I propose an alternative, the female tolerance hypothesis, in which decreased intrasexual aggression among females during the breeding season results in increased aggregation of males. Predictions of the female preference and hotspot hypotheses were examined in a population of greater prai~ie-chickens (Tympanuchus cupido) in northeastern Colorado during 1986-88. Nest-lek distances were used as indirect measures of home range size. Sixty-six of 89 females (74%) nested closer to a lek other than where captured and 67 of 79 females (85%) visited> 1 lek during the breeding season. These results contradicted predictions of the female preference hypothesis. Breeding potential was estimated as a measure of proximity between any given location and nest locations of females. Monte Carlo simulations were used to examine breeding potentials under. varying conditions of actual and random lek locations and actual and random distribution of nest locations. Distributions of both leks and nests supported predictions of the hotspot hypothesis. Examination of seasonal movement between breeding and wintering ranges indicated that spring migration occurred during February-March and autumn migration occurred during June-August. Most of the variability in timing of autumn migration for females appeared to be due to their brood status; females without broods migrated earlier than those with broods. The average migration distance between breeding and wintering ranges was 10.6 km for females and 2.9 km for males. Examination of seasonal locations for individuals between years indicated that most greater prairie-chickens displayed site fidelity to both breeding and winter areas. �A lek attendance rate of 50% for males has been used to estimate population size for greater prairie-chickens; consequently lek attendance was examined in northeastern Colorado during 1986-90. Observations of 21 radio-marked males indicated they were on leks 95.1% of the time during peak display periods (Mar-Apr); consequently use of 50% as a value for lek attendance may result in over-estimates of population size. Mean annual turnover rate of leks was 23.8%; 24 leks were active aIlS years. �41 DISSERTATION MOVEMENT AND DISPERSION OF GREATER PRAIRIE-CHICKENS IN NORTHEASTERN COLORADO Submitted by Michael A. Schroeder Department of Fishery and Wildl ife Biology In partial fulfillment of the requirements for the Degree of Doctor of Philosophy Colorado State University Fort Collins, Colorado Fall 1990 �42 COLORADO STATE UNIVERSITY 20 July 1990 WE HEREBY RECOMMEND THAT THE DISSERTATION PREPARED UNDER OUR SUPERVISION BY MICHAEL A. SCHROEDER ENTITLED MOVEMENT AND DISPERSION OF GREATER PRAIRIE-CHICKENS IN NORTHEASTERN COLORADO BE ACCEPTED AS FULFILLING IN PART REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY. Adviser /' ~:EhA-0.J~.~ Department Head �43 ABSTRACT OF DISSERTATION MOVEMENT AND DISPERSION OF GREATER PRAIRIE-CHICKENS IN NORTHEASTERN COLORADO Several hypotheses have been proposed to explain the evolution of .clumped (lek mating) from dispersed (territorial mating) polygyny; most recent mod~ls suggest that increased female home range size leads to increased female choice for males and/or leks. I propose an alternative, the female tolerance hypothesis, in which decreased intrasexual aggression among females during the breeding season results in increased aggregation of males •. Predictions of the female preference and hotspot hypotheses were examined in a population of greater prairie..: chickens (Tympanuchus cupido) in northeastern Colorado during 1986-88. Nest-lek distances were used as indirect measures of home range size. Sixty-six of 89 females (74%) nested closer to a lek other than where captured and 67 of 79 females (85%) visited> season. 1 lek during the breeding These results contradicted predictions of the female preference hypothesis. Breeding potential was estimated as a measure of proximity between any given location and nest locations of females. Monte Carlo simulations were used to examine breeding potentials under varying conditions of actual and random lek locations and actual and random distribution of nest locations. Distributions of both leks and nests supported predictions of the hotspot hypothesis. �...•...• Examination of seasonal movement between breeding and wintering ranges indicated that spring migration occurred during February-March and autumn migration occurred during June-August. variability Most of the in timing of autumn migration for females appeared to be due to their brood status; females without broods migrated earlier than those with broods. The average migration distance between breeding and wintering ranges was 10.6 km for females and 2.9 km for males. Examination of seasonal locations for individuals between years indicated that most greater prairie-chickens displayed site fidelity to both breeding and winter areas. A 1ek attendance rate of 50% for males has been used to estimate population size for greater prairie-chickens; consequently 1ek attendance was examined in northeastern Colorado during 1986-90. Observations of 21 radio-marked males indicated they were on leks 95.1% of the time during peak display periods (Mar-Apr); consequsnt ly use of 50% as a value for 1ek attendance may result in over-estimates population size. of Mean annual turnover rate of leks was 23.8%; 24 leks were active all 5 years. Michael A. Schroeder Department of Fishery and Wildlife Biology Colorado State University Fort Collins, CO 80523 Fall 1990 �45 TABLE OF CONTENTS TITLE PAGE ........................................................ i SIGNATURE PAGE ...•................................................ ABSTRACT ii .•...••.•••.••••......•.••...••.•......•......•......••..• ii; TABLE OF CONTENTS ACKNOWLEDGMENTS . vi viii •••••••••••••••.•••...•••••••••••.••.••••••..•.•••• CHAPTER 1. TOLERANCE AMONG FEMALES AND EVOLUTION OF LEKS . 1 . 1 Male fitness and evolution of l~ks •..........•.•.•.•.• Female fitness and evolutlon of leks ••.••...•......... Least costly male hypothesis ...•....•......•.•.. Female preference hypothesis ..•••••••••...••••.. Hotspot'hypothesis .•.••••.••.•••...•..•••.• ~•••. Hotshot hypothesis ..••••.....•..••••.•..•....••• Female tolerance ...•••..••..•.•••.••••.•.•...•.. 8 10 Rev; ew of hypotheses Proposed tests literature cited . .o •••••••••••• ~ ••••••••••••••••••••••••••••• CHAPTER 2. MOVEMENT AND LEK VISITATION BY FEMALE .GREATER PRAIRIE-CHICKENS: A TEST OF THE FEMALE PREFERENCE HYPOTHESIS OF LEK EVOLUTION ....•..•.........••.•............ I nt roduct ion Methods· Resul ts Home range size Lek visitation Di scussion " ~ . . . . . Literature cited ....•.•........••........•...•.......•...... CHAPTER 3. MOVEMENT BY FEMALE GREATER PRAIRIE-CHICKENS IN RELATION TO LEK LOCATION: EVALUATION OF THE HOTSPOT HYPOTHESIS OF LEK EVOLUTION 12 13 14 17 19 20 29 . ' 11 29 30 34 36 41 44 50 . 52 Introduction . 52 Methods . 54 Analysis Analysis Analysis Analysis 1 2 3 4 57 58 59 59 �46 TABLE OF CONTENTS (CONTINUED) Results..................................................... 60 Nest - capture lek movements ••..•••..•.••.•••..••..•.. 60 -1 •••••••••••••••••••••••••••••••••••••••••••• Analysi s 2 Analysis 3 ~.......................... 62 62 65 An a 1y sis Analysis 4 •••••••••••.•••••••.••.••••.•••••••.•...••.. Discussion •.••••••••••••••••••••••••••••••••••••••••.•.•.••• 65 68 Literature 69 ci ted CHAPTER 4. GREATER PRAIRIE-CHICKEN MIGRATION IN NORTHEASTERN COLORADO ••••••••••••••••••••••••••••••••••••••••••.••••••••• 70 Introduction Methods Results 70 ..•..........................•....................... 72 75 e;......... 75 Timing of movement .••.•..•....•••...•.•.•.•.••........ Distance of movement •••..••..••.••.•... :.............. Site fidelity 79 0.............. 89 Observat ion of movements •..•....•...•.•.••...•......... Di scussi on Literature cited ,. ' 0 • ,. • • • • • • • • • • • • • • • • • • • • • • • • 10................................ APPENDIX A. WALK-IN TRAPS FOR CAPTURING GREATER PRAIRIECHICKENS· IN NORTHEASTERN COLORADO 0 •••••••••••••••••••••••••• Examination of technique •••••.•••••••••••.•.••••••••.•.•.... Literature cited •••••••.••••••••••••••••••••••.•••.••.••••.• APPENDIX B. LEK PERSISTENCE AND ATTENDANCE OF MALE GREATER PRAIRIE-CHICKENS IN NORTHEASTERN .COLORADO ....•••............ Introduction Methods ..•.•..••.....•..•..•.. c...................... 0.0°............................ Results •••••••••••••••••.••••••••••••••••.••••••.•.........• Discussion................................... Literature cited ••.•••••••••••••.••..••••••.•.•••........... 93 • 95 101 105 105 112 114 114 115 117 131 134 �, 47 ACKNOWLEDGMENTS Financial support for this research was generously provided by the Colorado Division of Wildlife through Clait E. Braun. Academic supervision was provided by John T. Ratti and Gary C. White of the Department of Fishery and Wildlife Biology, Colorado State University. I am particularly grateful to Gary C. White for assuming the supervisory role for my project under unusual circumstances. Numerous people helped make this research possible. Rasmussen and Leslie A. Robb assisted with the fieldwork. Mary E. Robert E. Bennetts, Jack W. Bradbury, Cl ait E. Braun, Robert M. 'Gibson, Susan J. Hannon, Jerry W. Hupp, Richard L Knight, David B. Lank, Kathy Martin~ Orrin B. Myers, Leslie A. Robb, Frank A. Pitelka, Joel A. Schmutz, Beatrice Van Horne, Gary C. White, Marilet A. Zablan, and other graduate stUdents provided verbal input at different stages of the research. George Bear, C1ait E. Braun, Jack Dumbacher, Peter o. Dunn, Kenneth M. Giesen, N. Thompson Hobbs, Richard L.'Knight, Hans Landel,. John T. Ratti, Leslie A. Robb, Beatrice Van Horne, and Gary C. White reviewed drafts of proposals and chapters. I am particularly thankful for the continuous and unquestioning emotional support of Leslie A. Robb. ��49 CHAPTER 1. TOLERANCE AMONG FEMALES AND EVOLUTION OF LEKS REVIEW OF HYPOTHESES A common focus of research on mating systems has been the evolution of clumped (mating on leks) from dispersed (mating on territories) polygyny (Emlen and Oring 1977, Bradbury 1981). Clumped polygyny is characterized by the congregation of males at display sites, or leks, for breeding purposes; males typically provide no resources for females (Bradbury 1981, Payne 1984). Although observation of lek behavior in various species has been partly a function of intensity of research, examples have been documented within numerous families of animals (Table I-I). Early research on the evolution of behavior associated with leks included hypotheses of male emancipation 8(Alexander correlations (Snow 1963), display cycles 1974, Otte 1974, Buck and Buck 1978}, predation/habitat (Berger et al. 1963, Koivisto 1965, Boag and Sumanik 1969, Hjorth 1970, Wiley 1974, Wittenberger 1978), flocking (Kruijt et al. 1972), and density (Snow 1973h, Pitelka et al. 1974, Emlen and Oring 1977). These hypotheses generally focused on the importance of male behavior, since male fitness was considered to be more important than female fitness for understanding the ultimate causes for evolution of leks. The difficulty with hypotheses stressing the importance of male fitness has been with explaining tendencies of males to form leks when �I.J C Table 1-1. Descriptions of lek behavior by phylogeny. Phylum Class Order Family Common name Arthropoda Insecta Odonata Anlsoptera . Dragonfly Lepidoptera Papil ionidae Swa11owta il Diptera Gasterophil idae Botfly Drosophilidae Fly Hymenoptera Pompilidae Tarantula hawk wasp Vertebrata Osteichthyes Microcyprlni Poec 11iidae Gila topminnow Amphibia Salientia Continued. Scientific name Citations Plathemis l..mi! Campanella and Wolf 1973 Papilio zelicaon Shields 1967, Sims 1979 Gasterophilys intestinalis Catts 1979 Ringo 1976 Hodosh et ale 1979 Drosophila grimshawi Hemipepsis ustulata Alcock 1981 Orians 1969 Pocciliopsis occidentalis Constantz 1975 �Table 1-1. Continued. Phylum Class Order Family COl1l1lon .name Bufonidae Toad Ranidae Bullfrog Mammalia Chiroptera Pteropodidae .Hal1l1lerheaded bat Emba 11 onuridae Artiodactyla Bovidae Uganda kob Lechwe Topi Aves Scientific name Citation$ Bufo bufo Davies and Halliday 1978 Rana catesbaiana Emlen 1976 Hvpsignathus monstrosus Bradbury 19771, 1977R, Wrangham 1980 Bradbury 1977R, Bradbury and Vehrencamp 1976 Kobus kob Kobus leche Damiliscus korrigum Jarmen 1974 Buechner and Schloeth 1965, Buechner and Roth 1974, Wrangham 1980 Jarmen 1974 Gosling 1987 Oring 1982, Avery 1984, Payne 1984, Loffredo and Borgia 1986, Hoglund 1989 Galliformes Phasianidae Hjorth 1970, Wiley 1974, Wittenberger 1978, De Vos 1979, Sigurjonsdottir 1981 Continued. VI t-' �VI N Table 1-1. Continued. Phylum Class Order Family Common name Scientific name Citations Sage grouse Centrocercys urophasianus Capercalll1e Tetrao uroga11ys Black-billed capercai11ie Black grouse ht.rQ tetrix Wiley 1973, Wrangham 1980, Bradbury and Gibson 1983, Bradbury et al. 1986, 19891, h . Andreev 1979, ,Huller 1979, Moss 1980, Jones 1981 Andreev 1979 Koivisto 1965, Kruijt et a1. 1972, Kruijt and Hogan 1967, De Vos 1979, 1983 Sharp-tat led grouse Greater prairie-chicken Lesser prairie-chicken Great argus pheasant Lumsden 1968, Rippen and Boag 1974 Hamerstrom and Hamerstrom 1960, Robel 1966, Robel and Ballard 1974 Tympanuchus pa11idicinctus Hoffman 1963 .Gilliard 1963, Herton 1975, Davison Argusianus J.r!I!!1 Tympanychys cupjdo 1981 Gruiformes Otididae Great bustard Charadriiformes Sco10pacidae Ruff Pectoral sandpiper Continued. Otis tarda Cramp 1980 Philomachus pugnax Pitelka et a1. 1974, Hyers 1981 Hogan-Warburg 1966, Van Rhijn 1973, Pitelka et al. 1974 . Pite1ka 1959 Calidris melanotos �Table 1-1. Continued. Phylum Class Order Family Common name Buff-breasted sandpiper Painted snipe Great snipe Forest snipe Psittaciformes Psittacidae Kakapo Apodiformes Trochi lidae long-tailed hermit Reddish hermit Anna's hummingbird little hermit Hairy hermit Guy's hermit hummingbird Violet-headed hummingbird Crimson topaz Piciformes Indicatoridae Greater honeyguide lesser honeyguide Continued. Scientific name Citations Tryngites subruficollis Galljnago stenyra Gall inago media Gallinago megala MyerS 1979, Cartar and lyon 1988 Tuck 1972, Sutton 1981 Tuck 1972, Avery and Sherwood 1982, Hoglund 1987, Hoglund and lundberg 1987, Hoglund et al~ 1990 Tuck 1972, Sutton 1981 Strigops habroptilus Forshaw 1978, Merton et al. 1984 Phaethornis superciliosus phaethornis ryber Calypte "anna Phaethornis longuemareus Glaucis hirsuta phaethornis m Klais guimeti Jopaza pella Snow 1973h, Stiles and Wolf 1979 Stiles and Wolf 1979 Nicholson 1931, Snow 19731 Stiles 1973 Snow 1968, Wiley 1971 Snow 1973a Snow 1974~ 1977 Payne 1984 Payne 1984 Indicator indicator Indicator minor Friedmann 1955 Ranger 1955 Ranger 1955 VI W �VI ~ Table 1-1. Continued. Phylum Class Order Family Common name Scaly-throated honeyguide Passeriformes . Cotingidae Red-ruffed fruitcrow Rufous piha Red cot1nga Plum-throated cotinga Pihas Capuchinbird Cock-of-the-rocks Black-and-gold cotinga Umbrellab1rds Guianan cock-of-the-rock Pipridae White-bearded manakin Golden-headed manakin Striped manakin Fiery-capped manakin Wire-tailed manakin Swallow-tailed manakin White-throated manakin White-ruffed manakin Club-winged manakin Continued. Scientific name Citations Indicator variegatys Ranger 1955 Snow 1982 Snow 1982 Pyroderus scutatus Willis and Eisenmann 1979 lipaugys unirufus Snow 1982 phoenicircus carnifex Snow 1982 Cotinga maynana Snow 1982 Lipaugus sp. Snow 1982 perissocephalus tricolor Snow 1982 Rupicola sp. Snow 1982 TUuca atra Snow 1982 CephaJopterus sp. Trail 1985 Rupicola rupicola Sick 1967, Snow 1963 Manacus manacus lill 1974i, h Pipra erythrocephala lill 1976 Machaeropterus regylus Sick 1967 Machaeropterus pyrocephalus Sick 1967 finri fjlicauda Schwartz and Snow 1978 Chiroxiphia caudata Foster 1981 Corapipo guttyralis Snow 1963 Corapipo leucorrhoa Snow 1963 Machaeropterus deliciosus Willis 1966 �Table 1-1. Continued. Phylum Class Order Family Common name Pin-tailed manakin Band-tailed manakin Tyrannidae Ochre-bellied flycatcher McConnell's flycatcher Oxyruncidae Sharpbil1 pycnonotidae Yellow-whiskered greenbu1 Paradisaeidae Goldie's bird of paradise Count Raggi's bird of paradise Lesser bird of paradise Buff-tailed sicklebill Pti10norhynchidae Golden bowerbird Tooth-billed catbird Satin bowerbird Macgregor's bowerbird Ploceidae Jackson's whydah Pin-tailed whydah Scientific. name Citations 11icura mi1itaris fiDrj fasciicauda Mionectes oleagineus Mionectes macconne11i Payne 1984 Robbins 1985 Skutch 1960 Snow and Snow 1979 Willis et a1. 1978 Oxvruncys cristatys Stiles and Whitney 1983 Andropadys Jatirostris paradisaea decora Paradisaea raggjana Paradisaea minor Epimachus albertisi Brossett 1982 Schodde 1976, Cooper and Forshaw 1979 LeCroy 1981, LeCroy et a1. 1980 Payne 1984 Beehler 1983 Beehler 1987 Prionodura newtoni Scenopoeetes dentirostris Ptilonorhvnchus violaceus Amblvornis macgregoriae Gilliard 1969 Cooper and Forshaw 1979 Ve11enga 1970, Borgia et a1. 1985 Pruett-Jones and Pruett-Jones 1982 Eup1ectes jacksoni Vidua macroura Van Someren 1947 Shaw 1984 Vl Vl �56 most males have lower breeding success in a lek system than in a territorial system (Alexander 1974, Kirkpatrick 1982, Avery 1984). Recent work has focused on the importance of female fitness, including the female preference (Bradbury 1981), least costly male (Wrangham 1980), hotspot (Bradbury and Gibson 1983)~ and hotshot (Beehler and Foster 1988) hypotheses. Although each differs with respect to relative importance of male-male competition and unanimity of female choice, they are similar in that female choice drives the development of leks. However, none of these hypotheses provides a clear mechanism explaining the evolutio~ of lek behavior in a species. Emlen and Oring (1977) suggested that lekking tendencies were correlated with a decreasing ability of fem~les to defend their home ranges. Similarly, Bradbury (1981) indicated that- increased female home range size would lead to increased tendencies for males to form leks. However, little justification was given for possible causation in either case. Here I examine current theories on evolution and maintenance of lek behavior. I then propose the female tolerance hypothesis as a mechanism to explain the continuum between dispersed and clumped polygyny. I suggest that decreased intrasexual aggression among females during the breeding season permits increased female choice. The subsequent change in distribution of mating success among males leads to increased encroachment by 'unselected' males on 'selected' males. MALE FITNESS AND EVOLUTION OF LEKS Many hypotheses explaining evolution of lek behavior have suggested that the ultimate advantage to forming leks can be interpreted �57 in terms of male fitness. Hypothetically, whatever mating system males develop. females can adjust to One suggestion is that emancipation of males from parental duties permits development of leks (Snow 1963). However, male emancipation is common among both clumped and dispersed polygyny systems. Hence, while male emancipation may be a prerequisite for lek formation, emancipation may not result in lek behavior. Maximization of effectiveness of male displays has been suggested to lead to lek formation (Alexander 1974, Otte 1974). By concentrating in localized areas, males theoretically optimize the vocal, olfactory, and/or visual potential of their displays, thereby attracting more females. Consequently, clustered males should attract more females/male than single males. on intermittency Furthermore, leks should have an optimum size, based (periodicity) of each male"s display cycle (Bradbury 1977, Buck and Buck 1978). When the latter predictions were exami~ed (Hamerstrom and Hamerstrom 1955, Bradbury 1981, Dunn and Braun 1985), leks were found to be too large for their display potential to be adequately improved (i.e., there were fewer females/male on larger leks than smaller leks). Likewise, few males do most of the mating on leks, indicating that most males do not benefit solely from the lek's potential as a display site. Among the Tetraoninae, species mating on leks frequently occur in open areas, while species mating on dispersed territories occur primarily in forests or arctic/alpine areas (Hjorth 1970, Kruijt et al. 1972, Wiley 1974). surveillance One proposed reason is that cooperative predator is more effective in open country, hence males are more likely to form leks (Berger et ale 1963, Koivisto 1965, Boag and Sumanik �58 1969, Hjorth 1970, Wiley 1974, Wittenberger documentation been shown. 1978). However, little on the effects of predation on groups of various size has Kruijt et ale (1972) suggested that birds in open habitats may form social bonds while feeding in flocks with these bonds subsequently continuing into the breeding season. Unfortunately, these patterns are difficult to predict; forest species display a full range of dispersions, social behaviors, and mating systems (Snow 1963; Sick 1967; Snow 1973, 1974; Bradbury 1977). Snow (1973) suggested that increased male density, without increased resources, could force males to switch strategies from defense of resources to advertisement of breeding potential; lek species should have relatively high densities. While the importance of resou~ce . . abundance and male density on mating systems has been discussed by Emlen and Oring (1977) and Pitelka et ai. (1974), these ideas are not consistent with data on lek species (Bradbury 1981). FEMALE FITNESS AND EVOLUTION OF LEKS Most of the mating success on leks is obtained by relatively few males (Alexander 1974). The difficulty in understanding why males would form leks when most would have lower mating success than on territories is the principal reason for explaining the evolution of lek mating behavior in terms of a process initiated by females. Most current hypotheses that suggest females initiate the evolution of lek mating systems are directly or indirectly based on the premise that increased female home range size leads to increased opportunities for females to select males and/or leks (Bradbury 1981). Bradbury's hypothesis was ·similar to an earlier proposal by Emlen and �59 Oring (1977) which suggested that a necessary prerequisite for evolution of leks was the inability of females to defend their home ranges. Variability in home range size may explain the apparent continuum in level of dispersion among males of polygynous species (such as with 'exploded leks'; Gilliard 1963). Mating systems that are intermediate between clumped and dispersed polygyny may be common (Gilliard 1963, 1969; Lack 1968; Hjorth 1970; Ellison 1971, 1973; Schodde and McKean 1973; Gullion 1976; Payne and Payne 1977; Cooper and Forshaw 1979; Lill 1979; Bradbury 1981). Least Costly Male Hypothesis In the least costly male hypothesis, Wrangham (1980) suggested that females avoid leks close to nesting areas and select leks in nonnesting habitat. By selecting leks relatively far from nesting areas, females potentially reduce predation pressure around their nest sites, a factor that may be important during the nesting season when predation pressure on females is relatively high. The least costly male hypothesis may have less to do with lek evolution than with lek location (Wrangham 1980). However, since habitat may vary between lek and nest sites, a clear effect of nest-lek distance on predation pressure has not been detected. is no evidence that nest sites ~re concentrated lower predation. Likewise, there in specific areas of Since females presumably would make no special effort to reduce predation on their neighbors, males near nest sites of females may have the opportunity to breed with females which are not nesting nearby. Moreover, since most males have little opportunity to breed on leks, they should attempt alternative mating strategies, such as �ou displaying closer to nesting areas, even if they risk rejection by some females in the process. Female Preference Hypothesis Similar to Wrangham (1980), Bradbury (1981) suggested that female choice drives the process of lek evolution. preference' In Bradbury's 'female hypothesis females prefer and select large clusters of males, thus improving their opportunities for mate choice. The most important aspect of this hypothesis is the implied tie between female home range size and tendencies for males to form leks, because it provides insight into why some species may form leks and others may not. Unfortunately, Bradbury did not provide or suggest an adequate test of the hypothesis that increased home range size among females results in an increased tendency of males to form leks. Bradbury (1981) assumed that unanimity of female choice for certain males and/or leks would lead to a characteristic females and leks. distribution of He suggested that males would not congregate in areas . where females had the opportunity to visit other nearby leks. Subsequently, he predicted the distance between the 'active space' of adjacent leks should equal spring home range diameters of females (including the distance at which females can detect males) and that most females should visit only 1 lek during the breeding season. predictions These of female home range size and lek visitation are testable (despite problems with measuring home range size; Beehler and Foster 1988); examinations of published literature have lead to both support (Bradbury 1981) and rejection (Oring 1982) of the hypothesis that females are unanimous in their selection of males and/or leks. �61 Hotspot Hypothesis The hotspot hypothesis was proposed by Bradbury and Gibson (1983) to suggest that leks should form in areas of maximum overlap among home ranges of females (hotspots). This hypothesis suggested that clusters of males should form in areas of high female traffic; areas of female traffic should be influenced by home range.size of females. One difference between the female preference and hotspot hypotheses is that the latter accounts for leks that are more abundant (closer together), and females that may visit more than one lek during a breeding season. In other words, distance between leks could be used to reject the female preference hypothesis, but not the hotspot hypothesis. Bradbury and Gibson (1983) labeled the hotspot hypothesis of lek evolution as a process based on male fitness. distribution force. Nevertheless, size and of home ranges for females is the hypothesized driving For example, even though males theoretically clump at hotspots, these hotspots are determined by location, density, and movement of females. The major problem with the hotspot hypothesis is the difficulty of testing it (Bradbury et al. 1986). Beehler and Foster (1988) noted the circular nature of using female home ranges to determine hotspots, particularly when home ranges may be a function of lek location. predictions While about female lek visitation and lek dispersion may be tested, the results will not clearly support or reject the hotspot hypothesis. Nevertheless, some research has provided support for the hotspot hypothesis (Bradbury et al. 1989Q, Chapter 3). However, in certain species with specific resources associated with their breeding �62 season home ranges, examination of lek locations as a response to experimental manipulations of resources may provide an adequate test. Hotshot Hypothesis The 'hotshot' hypothesis suggests that male~male interactions determine both size and location of leks (Beehler and Foster 1988). Theoretically, a few 'hotshot' males should do most of the mating while other unsuccessful males should display near hotshots, resulting in clusters of males or leks (Foster 1983, Beehler and Foster 1988). The more a particular hotshot is selected by females, the larger his lek should be. Hence, removal of a hotshot should change the attendance of both males and females at a lek. Beehler and Foster's hypothesis is marginally different from the hotspot hypothesis which suggests that subordinate males determine whether to settle alone or join m~les in preferred locations. In the later case, males in preferred locations are assumed to obtain most of the copulations with females in an area. Whether these males are called 'preferred' or 'hotshots' seems irrelevant, as the result appears to be the same. Although Beehler and Foster (1988) treated the hotshot hypothesis as a process of lek evolution ultimately driven by considerations of male fitness (Lewin 1988), they suggested that female choice should lead to an intensification formation of leks. of male-male interactions, a precursor to They also suggested that the female preference and hotspot hypotheses would apply only if females were able to freely choose mates from among males on a lek, a possibility they considered improbable because of the importance of male-male interactions. �63 However, Bradbury (1981) suggested that the female preference hypothesis was dependent on unanimous choice by females for certain males and/or leks, not on unrestricted choice. Presumably, unanimity of choice would not be dependent on lack of male restrictions on female mate choice. In the case of the hotspot hypothesis, neither unrestrict~d or unanimous selection of females appeared to be essential (Bradbury and Gibson 1983). Beehler and Foster (1988) suggested several ways to test and differentiate hypotheses. among the hotshot, hotspot, and female preference First, they suggested that removal of hotshots and subsequent evaluations of lek disruptions and/or changes in female and male lek attendance could be used to differentiate between hotshot and other hypotheses (reduction in attendance predicted by .the hotshot model). This test would be difficult due to seasonal variability both female and male attendance4 in In addition, the predictions are not exclusive to the hotshot hypothesis. Disruptions in lek attendance would not constitute a rejection of either the female preference or hotspot hypotheses. If mate choice by females is important, then reductions in lek attendance (particularly by removal of a hotshot) may be predicted by both female preference and hotspot hypotheses. In addition, a decrease in lek size may cause a predicted decline in lek attendance in the female preference hypothesis. Beehler and Foster suggested a second test in which subordinate males could be removed on some leks, with males on other leks left as controls. If the hotshots remained on leks, female attendance should remain the same, regardless of the total lek size. suggested that this would differentiate Beehler and Foster among the female preference and �04 the hotshot - hotspot hypotheses, since the former predicts that females should start visiting larger leks. However, according to Bradbury (1981) and Bradbury and Gibson (1983) females may only have 1 lek within their home range, thus making additional lek visitation improbable, and at least, unpredictable. A third test proposed by Beehler and Foster is that dominance status be est.imated using more direct measurements, such as male-male interactions and mating disruptions, instead of male morphology (as with Gibson and Bradbury 1985). The hotshot model predicted that mating success should be more closely correlated with within-lek male dominance than with male morphology. Since this test is based on correlations, it does little to tease apart the 3 hypotheses. The final test proposed by Beehler and Foster involves an examination of seasonal and yearly variability in lek size. They suggest the hotshot hypothesis predicts more ('more' is undefined) variation than either the hotspot or female preference hypotheses. of a lek is hypothetically Size related to the length of tenure of the hotshot male(s); hence, variations in lek size would be related to differences in lengths of tenure. Although the hotspot hypothesis does not make a prediction about variability in lek size, the female preference hypothesis predicts that leks will have an optimum size and, therefore, will be less variable (Beehler and Foster 1988). The amount of variability needed to support or reject the hypotheses is difficult to quantify ('more' and 'less' are not defined). Therefore, like the previous tests, this argument does little to separate the 3 hypotheses. �65 Female Tolerance The least- costly male, female preference, hotspot, and hotshot hypotheses all suggest directly or indirectly that increased tendency for males to form leks is a consequence of increased ability by females to select males (Bradbury 1981). The primary differences between the hypotheses are that lek size and distribution are caused by unanimity of female choice for males and/or leks in the least costly male and female preference hypotheses, by maximization of male access to females in the hotspot hypothesis, and by male-male interactions in the hotshot hypothesis. Rarely do the theories present a mechanism which could lead to evolution of leks from a dispersed mating system. Even Bradbury (1981) interpreted the increase in female home range size as a correlative factor with lek formation and gave little justification possible causation. for In the hotspot and hotshot hypotheses, little information is given to explain a possible mechanism for lek evolution. Female home range size during the breeding season has obvious implications for a female's ability to select either leks or males (Bradbury 1981). a corresponding A result of increased female home range size, without decrease in female density, would be an increased probability of encountering conspecifics. Therefore, if territorial females increase the size of their home ranges, the response should be either a decrease in density or a decrease in territoriality Oring 1977). (Emlen and • While large female home ranges during the breeding season would permit increased female choice by permitting females to examine many males, the amount of freedom of female choice for males would be inversely correlated with levels of intrasexual aggression among �66 . females. If females are not able to tolerate other females within close proximity, as on a lek, the resulting female dispersion should create additional mating opportunities aw~ from normal display areas; this would tend to decrease rather than increase the aggregation of males. Hence, lek formation could result from increased sociality or tolerance among females, but not directly from large female home ranges in which females still maintain some conspecific intolerance or territoriality. Large home ranges do not, by themselves, explain why some males give up territories to pursue females into the territory of another male (a likely scenario resulting in territory breakdown). The originally- selected male would undoubtedly chase any intruding males out, as is typical with most territorial animals. from territoriality Therefore, it seems the change to lek mating would come at the point where defense of mates becomes more important than defense of territories, a point which is only reached when more than one female is present within the range of a male. If more than 1 female is with a male at the same time, other males may be able to encroach on the selected male. Likewise, the number of unselected males will be proportional to the unanimity of female selection (Hammerstrin and Parker 1987). The presence of more than 1 female would require female tolerance for other females •. Whether females arrive on the lek together or alone may not matter. The important consideration is that they tolerate each other within the territorial boundaries of the same male; even if the boundaries are on a lek. Relative differences in tolerance among females may explain why leks vary in dispersion from tight clusters to expanded formations ('exploded leks')(Bradbury 1981). Even on large leks (those with many males), evidence suggests that males maintain �67 relatively constant boundaries suggestive of territoriality. Furthermore, males also display site fidelity between years. Tolerance among females may be the key to understanding the evolution of lek mating systems; it may provide a testable alternative to the idea that home range size led to evolution of Iek mating systems. Possible reasons for conspecific tolerance may be found in feeding behavi or, food requi rements (causes for a 1arge range) '"or predation risks (possibly redu~ed by flocking)(Bradbury 1981). Lek mating systems are relatively common among avian species and harem mating systems are relatively common among mammalian species. Both systems are characterized by relatively large groups of females mating with relatively few males. If intrasexual tolerance among females can increase the likelihood of breeding on leks, an additional consideration would be to understand the difference between lek and harem mating systems. Differences in female mobility may explain some of these differences, exceptions to the generalities include antelope (Jarmen 1974) and bats (Bradbury and Vehrencamp 1976) among mammals and bustards (Cramp 1980), bar-headed geese (Anser indicus)(Lamprecht Buhrow 1987), and turkeys (Meleagris gallooavo)(Bent These considerations and 1932) among birds. raise the possibility that leks and harems may be identical with respect to the female tolerance hyp~thesis. PROPOSED TESTS The least costly male, female preference, hotspot, and hotshot hypotheses appear to pertain more to location and maintenance than to the evolution of leks. of leks Hence, I suggest that only 2 hypotheses explaining the evolution of lek behavior can be tested: 1) Bradbury's �(1981) model that increased female home range size leads to an increased tendency to mate on leks; and 2) the female tolerance hypothesis (breakdown in territory version proposed by Emlen and Dring [1977]). Test 1: Resources could be manipulated in species (preferably a species with behavioral plasticity) that mate either on leks or on territories (change dispersion of resources). A decrease in congregations of males in response to a decrease in home range size of females, or an increase in male congregations in response to an increase in home range size of females, would support Bradbury's (1981) hypothesis and the female tolerance hypotheses. If increased female home range size leads to increased tolerance of conspecifics, the predictions of Bradbury's (1981) home range model and the female tolerance hypothesis are not m~tually exclusive. Test 2: manipulated ~evels of aggression in females could be artificially (hormone administration, Wingfield [1984]) and the subsequent pattern of male and female spacing analyzed. If female aggression could be artificially increased, males should respond by increasing their dispersion and/or decreasing their tendency to display on leks. effect. A decrease in female aggression should have the opposite If home range size remained constant, this test would be used for rejection of Bradbury's (1981) hypothesis and support of the female tolerance hypothesis. LITERATURE CITED . AlcoCK, J. 1981. Lek territoriality in the tarantula hawk wasp Hemipepsis ustulata (Hymenoptera: Pompilidae). Behav. Ecol. Sociobiol.8:309-317. Alexander, R. D. 1974. The evolution of social behavior. Ecol. 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D. 1947. The dancing display and courtship of Jackson's whydah (Coliuspasser jackson; Sharpe). E. Afr. Nat. Hist. Soc. J. 18:131-141. Vellenga, R. E. 1970. Behaviour of the male satin bowerbird at the bower. Austr. Bird Bander 8:3-11. Wiley, R. H. 1971. Song groups in a singing assembly of little hermits. Condor 72:28-35. ______ • 1973. Territoriality and non-random mating in sage grouse, Centrocercus yrophasianys. Anim. Behav. Monogr. 6:85-169. _____ . 1974. Evolution of social organization and 1ife history patterns among grouse (Aves:Tetraonidae). Q. Rev. Biol. 49:201227. Willis, E. O. 1966. Notes on a display and nest of the club-winged manakin. Auk 83:475-476. ______ , and E. Eisenmann. 1979. A revised 1ist of birds of Barro Colorado Island, Panama. Smithson. Contrib. Zool. 291. 31pp. ______ , D. Wechsler, and Y. Oniki. 1978. On behavior and nesting of McConnell's flycatcher (Pipromorpha macconnelli): does female· rejection lead to male promiscuity? Auk 95:1-8. Wingfield, J. C. 1984. Androgens and mating systems: testosteroneinduced polygyny in normally monogamous birds. Auk 101:665-671. Wittenberger, J. F. 1978. Condor 80:126-137. The evolution of mating systems in grouse. Wrangham, R. W. 1980. Female choice of least costly males; a possible factor in the evolution of leks. Z. Tierpsychol. 54:357-367. �77 CHAPTER 2. MOVEMENT AND LEK VISITATION BY FEMALE GREATER PRAIRIECHICKENS: A TEST OF THE FEMALE PREFERENCE HYPOTHESIS OF LEK EVOLUTION INTRODUCTION Current hypotheses explaining evolution of lek behavior from territoriality, its hypothesized precursor, suggest that females initiate the process of lek evolution (Emlen and Dring 1977, Wrangham 1980, Bradbury 1981, Bradbury and Gibson 1983, Beehler and Foster 1988). Increased home range size theoretically leads to an increased ability to select males and/or leks. Increased female home range size may also explain the continuum between lek and territorial species (Bradbury 1981). Whether large home ranges are caused by clumped food sources, predation, or other unexplained factors is unresolved; Bradbury (1981) suggested that female choice drives lek evolution. In Bradbury's 'female preference' hypothesis, females prefer and select large clusters of males, thus improving their opportunities choice. for mate Bradbury assumed that unanimity of female choice for certain leks would lead to a characteristic distribution of females and leks; females should have spring home range diameters equal to inter-lek distances and most females should visit only 1 lek during the breeding season. In this paper I will test the female preference hypothesis by examining lek visitation and home range size of female greater prairiechickens. If most females visit more than 1 lek or have home ranges �78 that include more than 1 lek, the female preference hypothesis can be rejected. METHODS Greater prairie-chickens were studied in 1986-88 on a 301-km2 study area centered (40 11' N, 102 22' W) 10 km northeast of Eckl ey, 0 Colorado (Fig. 2-1). 0 The area consisted of grassland, sand sagebrush (Artemisia filifolia), and small soapweed (Yucca glauca) intermixed with irrigated fields of agriculture, primarily corn. Locations of leks (2 or more displaying males) and maximum male attendance at each lek each year were based on at least 2 observations. Trapping was concentrated on a core area of approximately 100 km2• Female greater prairie-chickens were captured at winter feeding sites using walk-in traps baited with corn and on leks using walk-fn traps and cannon nets. Captured females were banded with a numbered aluminum band and a unique combination of 3 colored plastic bands, and fitted with battery- or solar-powered markers (Amstrup 1980). each birds' body weight. radio transmitters attached to poncho-type Radio weights ranged between 1.8 and 2.3% of Birds were classed as yearlings (first breeding year) or adults (> first breeding year) (Ammann 1944). Observations of birds were made during early (IS Feb-31 Mar) and late spring (1 Apr-IS May); designation of seasons was based on aspects of breeding behavior and movement (Robel et ale 1970). Radio-marked greater prairie-chickens were located using a portable receiver and 3-element Yagi antenna. Daily observations for each bird were obtained by triangulation; transmitters 3 or more azimuths were obtained ~ 1.5 km of target and at angles-of-incidence greater than 35 and less than 0 �79 MEAN YEARLY LEK ATTENDANCE 0·1 >1·3 >3·6 • o 0 4460 e- : , ,:: :. z ::! 0 : :: 0 0 : : :....: ~o' ~ ~ 0 ,: 1 o - BAITSITES >15 .. : "', ~ 0 .. ~ ~ ~ 0 : .! 4450 -; 5 LEKS * • ~ ~;--·r::-~i··;J:=:~*....... !..... t;: r,' , ~ >10·15 000 J~7····~-··r~~~""":~~&"c,O<~. .. N : [4455 >6·10 CAPTURE SITES ~ + '~O· I0 , l 0 . I: ,~. I ""f": : :'" :' • ~: ~L·········f··········.•• ···························I·.o············~:.:·~··················· .~ ~ r::::.· ~ • i.: : ~ ·.·.··.. I '''''.. : ~ <e-.......•.......~ : : '- - ~ -, ~ 0 : ~ o?J o· 0 4445 r-············t······...•·~·~···'························l································~·········t··········· (d Q ' .. I0 "", : b 0 : ~ r-- 0 EC~EY ".. ...:0 1 1 1 : : i ~..--+----------i----------1------J 720 725 !.. o - 0: 715 , , 730 , ,,' 735 UTM (KM EAST) Fig. 2-1. Locations of leks and capture sites on greater prairie- chicken study area in 1986-1988 (301 km2 outlined by dashed boundary) in northeastern Colorado. �80 145°. All locations were recorded using Universal Transverse Mercator coordinates (nearest 10-m interval). Home range size was estimated as the area within a 75% probability contour generated with harmonic means (grid size of 25 X 25) for each radio-marked female for each season (Dixon and Chapman 1980). The accuracy of the triangulation technique was examined with 13 test transmitters placed on the ground (by another observer) in a relatively hilly 4-~ area, 1-2 km from the nearest access points. The area was chosen because it was inaccessible relative to the majority of the study area. Five azimuths were obtained for each transmitter from each of 5 locations (4 locations for 3 transmitters). The standard .deviation between observed and average azimuths was 2.10° (n - 310). In contrast, estimated azimuths deviated an average of 6.97° from actual azimuths (the overall bias was -1.66°). Most of the variation· apparently was due to the location where the azimuth was obtained and the transmitter that was being located. Estimated locations were compared with actual locations of nests, dead birds, and test transmitters (Fig. 2-2). About 90% of the locations derived by triangulation were within 250 m of actual locations. Although this sample was not affected by problems associated with bird movement, other factors may have adversely affected accuracy; transmitters usually were close to, or on, the ground. Transmitters from dead birds frequently were buried, upside down, and/or damaged (chewed); transmitters on nesting fem~les were usually in dense vegetation, close to the ground, and shielded by the female. In the female preference hypothesis, Bradbury (1981) specifically predicted that: 1) the diameter of female home ranges should be less �81 2S,_----~~------------------------------------------, [] TEST TRANSMITTERS E1 SITES OF NESTS &1 SITES OF DEAD BIRDS 20 a: 1S w c::l :::E :::::3 Z 10 S o 0·25 50·75 100·125 150·175200·225 250·275 300-325350-375 400·425 450·475500·525 DISTANCE BElWEEN Fig. 2-2. ACTUAL AND ESTIMATED LOCATIONS (M) Distribution of distances between estimated and actual locations of 13 test transmitters, prairie-chickens 79 nests, and 44 dead greater in northeastern Colorado, 1986-88. �than inter-1ek distances, 2) most females should have only 1 1ek within their home range, and 3) each 1ek should have an exclusive population of females. Thus, most females should visit' only 1 1ek. was not defined by Bradbury, I conservatively Although 'most' defined most as > 50%. The validity of the specific predictions were examined by Beehler and Foster (1988). I examined Bradbury's predictions for the female preference hypothesis by identifying lek - nest distances (an indirect measure of home range size) and 1ek visitation by female greater prairie-chickens. Home range size for females was estimated for both early (prior to most lek visitation) and late spring (during lek visitation and nest establishment). probability Home range size was estimated as the area within a 75% contour generated with harmonic means (grid size of 25 X . 25); this was a conservative estimate of home range size (Dixon and Chapman 1980). Additionally, home range diameter was calculated as though each home range was a circle (conservative estimate of diameter). RESULTS Radios were placed on 36 adult and 56 yearling female greater prairie-chickens during 1986-88 breeding seasons. Since spring capture techniques potentially disturb females, data from an 'undisturbed' sample of 12 adults and 7 yearlings captured at feeding sites during winter 1987-88 were examined as a 'control'. Sixty-five different leks were located on the study .area during 1986-88 (Fig. 2-3). All leks were not active from year-to-year; and 47 were located during each breeding season, respectively. 41, 42, The mean distance between a lek and its nearest neighbor was 1.31 ± 0.56 (~ ± �83 N SIZE OF LEKS . 0 0 ·0 0 00 2-5 MALES 6-10 MALES 0 .• 0 0 0 0 • 0 o 0 11-15 MALES >16 MALES 0 0 <e 0 0 0 0 2 4KM , • I , , 0 0 0 '0. 0 0° • o· ° "'0 0 ! 0 0 °0 00 ~a 0 0 0 0 cc 0 0 0° . e • 0 0 0 0 0 Fig. 2-3. • Distribution and size of greater prairie-chicken northeastern Colorado, 1986-88. leks in �u"t SO), 1.20 ± 0.70, and 1.18 ± 0.62 km each year, respectively (medians of 1.42, 1.32, 1.15 km). Home Range Size Distances between nest locations and both the nearest 1ek and the 1ek where each female was first observed were determined separately for Females (n - 89) nested an average of 3.62 km each year (Fig. 2-4). from leks where they were first observed (Table 2-1); some females moved relatively long distances (Fig. 2-5). Hens (n s 81) nested an average of 1.00 km from the nearest 1ek (Table 2-1) with distances ranging from 0.23 to 2.39 km (Fig. 2-6). Eight of 89 females nested off the study area; hence, distances to the nearest 1ek could not be determined. There was no difference in distance between the 1ek where each female was first observed and her nest that could be attributed to year (f - 1.35, f - 0.265). However~ yearling females tended to move further between the 1ek where first observed and their nest site than adults (f - 3.89, f - 0.052); the difference may be partially attributable to yearling dispersal. distances For instance, the 5 females with the longest (18-29 km) between nests and the 1ek where first observed or captured, were yearlings. In addition, 12 of 16 movements> 5 km were f - 0.611) or by yearlings. There was no difference by year (f - 0.50, age (f - 0.02, f - 0.901) for nest-nearest 1ek distance (Table 2-1). Disturbance may also have been a factor. Females captured during the breeding season (disturbed) had longer distances between 1ek first visited and nest site (1 = 2.352, f - 0.022) than females captured prior to the breeding season (undisturbed). Undisturbed females may have been marked prior to normal movements between seasonal home ranges. �85 1986· N o LEKS * NESTS 1987 1988 o Fig. 2-4. Distribution of female greater prairie-chicken 2 4 KM nests in relation to lek where each female was first observed or captured in northeastern Colorado, 1986-88. �00 Table 2-1. Distances (m) between greater prairie-chicken nests and leks in northeastern Colorado, 1986-88. Lek nearest to nest Lek visited first Category 11 so Median 11 so Median Year 1986 22 2.09 2.86 2.11 21 0.84 0.96 0.53 1987 31 1.65 2.91 4.34 29 0.78 0.94 0.53 1988 36 1.86 4.71 6.84 31 1.14 1.08 0.47 Adult 42 1.79 2.28 2.25 38 0.97 0.98 0.51 Yearling Status.1I 47 2.04 4.82 6.62 43 0.96 1.01 0.52 Undisturbed 14 1.87 2.01 1.87 14 1.05 1.16 0.51 Disturbed 75 1.98 3.92 5.55 67 0.84 0.96 0.50 89 1.93 3.62 5.19 81 0.96 1.00 0.50 Age- Totals -One female of unknown-age was excluded from the sample for nearest lek - nest distances. IIFemalescaptured prior to lek visitation were considered undisturbed and those captured on leks during lek visitation were considered disturbed. �87 ~~----------------------------------------------, YEARLINGS 15 • en ADULTS w ..J ~10 W LL 5 o 5 10 15 ~ 25 30 DISTANCE (KM) Fig. 2-5. Distribution of distances between 89 female greater prairie- chicken nest sites and leks where each female was first observed or captured in northeastern Colorado, 1986-88. �88 10 YEARLINGS 8 ffi _J II ADULTS 8 < ~ W u.. 4 2 o 0.0 0.5 1.0 1.5 2.0 2.5 DISTANCE (KM) Fig. 2-6. Distribution of distances between 82 female greater prairie- chicken nest sites and nearest lek in northeastern Colorado, 1986-88. �89 Consequently, 4 undisturbed females moved 6-18 km prior to being observed on leks during the breeding season. In contrast, all disturbed females were observed on leks, often prior to making similar long movements. Hence, distances between lek first visited and nest site were biased toward shorter distances for undisturbed females. There was no difference for nest-nearest lek distance attributable to disturbance (1 - 1.660, f - 0.113)(Table 2-1). Sixty-six of 89 females (74%) nested closer to a lek different from the lek where they were first observed or captured. When compared with a maximum predicted value of 50%, the observed value was higher (~ - 20.775, f < 0.001). Disturbed females (76.0%, n • 75), did not differ from undisturbed females (64.3%; n - 14)(~ • 0.845, f - 0.431). If disturbance was a factor, disturbed females would be expected to avoid leks where they were captured. There were no differences in home range size associated with sex, age, or disturbance status (f > 0.10)(Table 2-2). However, home range size during late spring (X • 624 hal was larger (1 - 2.098, f than in early spring (X - 213 ha)(Table 2-2). a 0.038) The average diameter for home ranges was 1.51 km (SO - 0.66) during early spring and 2.24 km (SO - 1.71) in late spring. These estimates are greater than distances between neighboring leks (mean yearly range of 1.18-1.31, median range of 1.15-1.42). Lek Visitation Seventy-nine radio-marked females were observed on leks at least twice during the breeding season; 84~8% of these females were observed on more than 1 lek (Fig. 2-7), which was greater (~ • 38.291, f < �90 Table 2-2. Home range size (ha) for female greater prairie-chickens in northeastern Colorado, 1986-88. Early spring Category n Median Late spring ! SO n Median ! SO Year 1986 3 165.0 149.3 115.6 21 252.5 526.9 749.8 1987 2 328.7 328.7 247.9 36 264.4 349.4 287.8 1988 25 156.8 210.9 252.7 40 310.9 921.6 2861.1 Adult 22 165.0 175.9 97.2 49 266.0 369.2 304.7 8 134.9 313.6 439.2 48 271.0 883.7 2645.6 24 160.8 231.3 260.1 19 461.3 625.1 959.1 6 113.1 137.7 111.6 78 260.4 623.5 2049.0 30 160.8 212.6 239.3 97 266.0 623.8 1881.5 Age Yearling Status· Undisturbed Disturbed Totals ·Females captured prior to lek visitation were considered undisturbed and those captured on leks during lek visitation were considered disturbed. �91 - 0=15 ~ ~ ~ ~ ~ ,~ ,~ ~ --b-· OISTURBEO ~ ~ 0=22,, 0=34 Z CiS 5 90 ... . 0-79 -- - .. fo .... . 85 8..... W LL. ,, 0=56 •• •• "Z:1 ••••••••••• 'E:l .•. ........ .0" ,, , , --8' : , .Q A .•.• , , , ,, I A J= : I ····8···· 95 n=6 ,~A-------- TOTAL 0 UNOISTURBEO 100 .0. . o 80 2 345 6 MINIMUM NUMBER OF LEK VISITS Fig. 2-7. Proportion of female greater prairie-chickens visiting more than 1 lek in relation to number of times observed on a lek in northeastern Colorado, 1986-88. 7 �92 0.001) than the hypothesized upper-limit of 50%. Undisturbed females (88.2~, n • 17) did not differ from disturbed females (83.9%, n - 62) in their likelihood to visit more than 1 lek ()( • 0.197, f - 0.741). If disturbance was a factor, disturbed females should have visited more leks than undisturbed females. As number of visits to leks increased, number of visits to different leks also increased (Fig. 2-8). One yearling female was observed on 6 different leks in 8 1ek visits. Another yearling female visited the same lek on 9 consecutive observations. Capture as a possible disturbance factor was examined by compiling data on consecutive lek visits (Fig. 2-9). If females were adversely affected by being captured they should be expected to avoid the capture lek on their next lek visit. However, there was no difference ()( - 0.192, f· 0.740) in the likelihood to visit a different lek on the second 1ek visit between distyrbed (75.8%) and undisturbed females (70.6%). The probability of visiting a different lek on lek visit 2 (n - 79, 74.7~) was less ()( • 7.889, f • 0.005) than in lek visits ~ 3 (n - 137 combined, 55.5%). The tendency to visit the same lek(s) in later visits may represent selection for leks by females, as opposed to effects of disturbance. DISCUSSION Bradbury predicted that most females (presumably more than 50%) should have home ranges that include only 1 1ek and that they should visit only 1 lek. However, most female greater prairie-chickens (74%) nested closer to a lek other than that where captured and most (85%) visited> 1 lek during the breeding season. Similarly, Svedarsky (1988) �93 7,--------------------------------------------------, TOTAL o UNDISTURBED --b.-- DISTURBED .... ;:J .... MAXIMUM NUMBER OF DIFFERENT LEK VISITS POSSIBLE 3 4 5 >5 LEKVISIT Fig. 2-8. Number of different leks visited by female greater prairie- chickens in relation to number of times they were observed on leks in northeastern Colorado, 1986-88. �94 ~ 80,-----------------------------------------------~ t: - TOTAL >. UNOISTURBEO en ~ ~ o --b-· 70 .• 0-79.... o .. OISTURBEO ····8···· .... .. .•. ... 0,.,56 .... .• .•. •. .•. •••• •t, ~ e, ~ 60 ,, , ffi ffi H: 0=22 .. ~....- .. .... 50 .. •., ,&,.... " •, "'" ..·8········ , D=25 , -El C t: ·en s ~ 40 ~~--------~~--------~----------~----------~~ 2 3 4 5 >5 ·LEKVlSIT Fig. 2-9. Likelihood of a female greater prairie-chicken visiting a lek different than the previous lek visited in relation to the consecutive number of her lek visit in northeastern Colorado, 1986-88. �95 found that 11 of 18 (61%) females in Minnesota nested closer to a lek other than that where captured. Although direct examinations of home range size are difficult, and possibly not interpretable (Beehler and Foster 1988), home range sizes were estimated to provide an additional evaluation of the relevancy of Bradbury's (1981} prediction that diameters of home ranges should be less than distances between neighboring leks. The average home range diameter (based on only 75% contours) was larger than predicted, despite the fact that a detection distance (distance at which males can be detected read i1y by females) was not added to the home range diameter (Bradbury 1981). Home ranges for 20 female sage grouse in California were also larger than predicted; they each included an average of 2.2 leks (Bradbury et al. 1989. It was not logistically feasible to detect all lek visits and movements by females. Therefore, measures of home range size and lek visitation are probably conservative. These results do not support Bradbury's (1981) predictions that females should visit only one lek and have home ranges that include only one lek. Thus, Bradbury's preference' hypothesis is rejected for greater prairie-chickens northeastern 'female in Colorado. One possible reason for rejecting the female preference hypothesis may be that distribution of resources has changed since the lek mating system evolved among greater prairie-chickens. observations For example, of large home ranges in this study partly appeared to be a function of the distribution of important resources such as corn (in center-pivot irrigated fields). If resources were dispersed more evenly throughout the range of greater prairie-chickens, lek visitation and �home range size of females might approximate the predictions of Bradbury (1981). Although historical changes in habitat of greater prairie-chickens have been dramatic, their original North American habitat has been difficult to document adequately. that greater prairie-chickens Most available evidence indicates survived on acorns (Quercus spp.) prior to introduction of cereal grains (Bogardus 1874, Brewster 1890, Judd 1905, Leopold 1931, Hamerstrom'et al. 1941, Sharpe 1968). historical distribution of greater prairie-chickens Consequently, was altered by both movement of agriculture north and west, and transformation savanah and oak woodland/grassland the of oak- into cropland (Bogardus 1874, Cooke 1888, Gross 1930, Leopold 1931, Schmidt 1936, Hamerstrom and Hamerstrom 1949). Since oak trees were hypothesized to exist in scattered clumps and groves throughout the original' range of the greater prairie-chicken (Kuchler 1964), it is doubtful that resources were ever evenly dispersed. The most important aspect of Bradbury's (1981) theory is the relationship form leks. between female home range size and tendencies for males to Sizes and distributions of home ranges may provide insight into why some species form leks and others do not. Unfortunately, Bradbury (1981) did not clearly explain how increased home range size of females could result in,the development of lek behavior by males. Other hypotheses, 'least costly male' (Wrangham 1980), 'hotspot' (Bradbury and Gibson 1983), and 'hotshot' (Beehler and Foster 1988), have incorporated the idea that increased opportunities for mate choice by females can result in the evolution of lek mating systems. While Bradbury (1981) suggested that female preference could result in a �97 predicted distribution of leks and female home ranges, his proposed predictions did not provide an adequate test for the theory that increased home range size ultimately leads to increased concentrations of males (Chapter 1). Similarly, recent hypothesis have done less to examine the importance of female choice than to interpret factors such as male-male competition (Beehler and Foster 1988), variable male breeding potential (Bradbury and Gibson 1983), and selection of males in non-nesting habitat (Wrangham 1980). Movements of females also have implications for management of greater prairie-chickens and other lek species. land use practices in areas critical to 1ek species may be modified to conform to specifications relating to 1ek locations. One way this may be done is to delineate an arbitrary circumference of habitat around all known leks~ Th.se ar~as are generally corisidered the most critical for nesting, a factor considered when mitigating for habitat disturbance or loss. However, little information is available describing female movements and nest sites in relation to 1ek location. For example, Beck (1977) and Connelly et al. (1988) showed that Wal1estad and Pyrah's (1974) arbitrary radius of habitat (3.2 km) that should be protected around sage grouse (Centrocercus urophasianus) leks would not be effective for populations because of larger than expected movements. The problem of delineating habitat may be of particular importance for greater prairie-chickens establishment in northeastern Colorado. of greater prairie-chickens The re- into formerly occupied range may necessitate additional information on both the critical features of nest sites and on the proximity of nests to lek sites. �98 Management of greater prairie-chickens in northeastern Colorado would be difficult if based on selection of arbitrary regions of habitat around known lek locations. Although all female greater prairie- chickens nested within 2.5 kIDof a lek, arbitrary selection of habitat within 2.5 kIDof .leks results in delineation of approximately 99% of the 300 ~ study area. Hense, if the management objective is to adequately protect nesting habitat for greater prairie-chickens (a logical objective), a procedure based on lek locations does little to delineate nesting habitat from non-nesting habitat. LITERATURE CITED Ammann, G. A. 1944. Determining age of pinnated and sharp-tailed grouses. J. Wildl. Manage. 8:170-171. Amstrup, S. C. 1980. 44:214-217. A radio-collar for game birds •. J. Wildl. Manage. Beck, T. D. I. 1977. Sage grouse flock characteristics selection in winter. J. Wildl. Manage. 41:18-26. and habitat Beehler, B. M., and M. S. Foster. 1988. Hotshots, hotspots, and female pref~rence in the organization of lek mating systems. Am. Nat. 131:203-219. Bogardus, A. H. 1874. Field, cover, and trap shooting. Co., New York, N.Y. 343pp. J. B. Ford and Bradbury, J. W. 1981. The evolution of leks. Pages 138-169 in R. D. Alexander and D. W. Tinkle. eds. Natural selection and social behavior: recent research and new theory. Chiron Press, New York, N.Y. ___ , and R. M. Gibson. 1983. Leks and mate choice. Pages 109-138 in P. Bateson. ed. Mate choice. Cambridge Univ. Press, Cambridge, U.K. ___ , , C. E. McCarthy, and S. L. Vehrencamp. 1989. Dispersion of displaying male sage grouse. II. The role of female dispersion. Behav. Ecol. Sociobiol. 24:15-24. Brewster, W. 1890. The heath hen. Forest and Stream 35:188. �99 Connelly, J. W.,· H. W. Browers, and R. J. Gates. 1988. Seasonal movements of sage grouse in southeastern Idaho. J. Wi1d1. Manage. 52: 116-122. Cooke, W. W. 1888. Report on bird migration in the Mississippi Valley in the years 1884 and 1885. U.S. Dep. Agric., Div. Econ. Ornith., Bull. 2. 313pp. Dixon, K. R., and J. A. Chapman. 1980. Harmonic mean measure of animal activity areas. Ecology 61:1040-1044. Emlen, S. T., and L. W. Oring. 1977. Ecology, sexual selection, and the evolution of mating systems. Science 197:215-223. Gross, A. O. 1930. Progress report of the Wisconsin prairie chicken investigation. Wisconsin Conserv. Comm., Madison. 112pp. Hamerstrom, F. N., Jr., and F. Hamerstrom. 1949. Daily and seasonal movements of Wisconsin prairie chickens. Auk 66:313-337. ___ , F. Hopkins, and A. J. Rinzel. 1941. An experimental study of browse as a winter diet for prairie chickens. Wilson Bull. 53:185-195. Judd, S. D. 1905. The grouse and wild turkeys of the United States and their economic value. U.S. Bur. Bio1. Survey, Bull. 24. 55pp. Kuchler, A. W. 1964. Potential natural vegetation of the conterminous . United States. Am. Geogr. Soc. Spec. Pub1. 36. Leopold, A. 1931. Report on a game survey of the North Central States. Am. Game Assoc., Madison, Wisc. 299pp. Robel, R. J., J. N. Briggs, J •.J. Cebula, N. J. Silvy, C. E. Viers, and P. G. Watt. 1970. Greater prairie chicken ranges, movements, and habitat usage in Kansas. J. Wi1d1. Manage. 34:286-306. Schmidt, F. J. W. 1936. Winter food of the sharp-tailed grouse and pinnated grouse in Wisconsin. Wilson Bull. 48:186-203. Sharpe, R. S. 1968. The evolutionary relationships and comparative behavior of prairie chickens. Ph.D. Thesis, Univ. Nebraska, Lincoln. 187pp. Svedarsky, W. D. 1988. Reproductive ecology of female greater prairie chickens in Minnesota. Pages 193-239 in A. T. Bergerud and M. W. Gratson. eds. Adaptive strategies and population ecology of northern grouse. Vol. I. Univ. Minnesota Press, Minneapolis. Wallestad, R., and D. B. Pyrah. 1974. Movement and nesting of sage grouse hens in central Montana. J. Wildl~ Manage. 38:630-633. Wrangham, R" W. 1980. Female choice of least costly males; a possible factor in the evolution of leks. Z. Tierpsychol. 54:357-367. �100 CHAPTER 3. MOVEMENT BY FEMALE GREATER PRAIRIE-CHICKENS IN RELATION TO LEK LOCATION: EVALUATION OF THE HOTSPOT HYPOTHESIS OF LEK EVOLUTION INTRODUCTION Bradbury (1981) was the first to suggest that increased female home range size could result in an increased ability by females to select males and/or leks. In the 'female preference' hypothesis, he suggested that female choice drives the process of lek evolution. Subsequently, Bradbury and Gibson (1983) proposed the 'hotspot' hypothesis in which they suggested that males form clusters in areas of high female traffic. The major objective of this research was to evaluate the feasibility of the hotspot hypothesis by examining associated predictions with respect to lek locations and patterns of movement by female greater prairie-chickens in northeastern Colorado. The basic prediction of the hotspot hypothesis is that female traffic determines lek location. Although this prediction is difficult to test (Bradbury et al. 1986, Beehler and Foster 1988), Bradbury et al. (1986) suggested that overlap in female home ranges could be used to determine optimum lek locations, thus permitting comparison of optimum and actual lek locations. Unfortunately, even if home ranges can be determined accurately, possible biases associated with female movements to leks cannot be avoided. Beehler and Foster (1988) noted the circular nature of using �101 female home ranges to determine hotspots, particularly when home ranges may be a function of lek location. Also, there are no A prior; ways to determine how close or far apart optimum and actual lek locations should be to support or reject the hotspot hypothesis. differences Finally, inevitable in trapping intensity and absence of a completely marked female population must be dealt with. I used the actual distances between each female's nest site and lek where she was captured as indirect measures of home range size. Use of this procedure avaoids problems with estimation of female home ranges (Beehler and Foster 1988) and the absence of a completely monitored population and takes into account the importance of female ability to move between their home ranges and leks. Complexity of potential biases is the major reason why analysis of the hotspot hypothesis is complicated. Consequently, 4 separate analyses were used to examine the relationship between lek locations and areas of female traffic; all analyses were designed to test the prediction that leks were in areas of high female traffic. Since each analysis could have strengths and weaknesses, the overall results for the 4 analyses should provide a better examination of the hypothesis. An initial analysis was conducted to provide the suggested comp~rison between breed~ng potential at optimum and actual lek locations (Bradbury et al. 1986). Since this analysis was potentially affected by numerous biases, including methods used for trapping females, additional analyses were conducted. A second analysis was designed to examine breeding potential at actual display sites and determine the relative importance of lek size, lek stability (on a yearto-year basis), and trapping intensity. Although the second analysis �. 102 enabled an examination of all leks, most leks were on portions of the study area where no females were trapped. Consequently, they were in locations with few or no marked nesting females. . A third analysis was conducted to analyze breeding potential at leks on the core portion of the study area only. One objective was to compare breeding potential at actual and random lek locations. characterized Unfortunately, the previous 3 analyses were by bi~ses that made direct comparisons of breeding potential at actual and random lek locations difficult to analyze and interpret. Even though random locations could be selected within a study area that was large enough to include all female nest sites, the density of radio-marked females would be greatest in the middle of the study area. Hence, proportionally more random locations would be on the edge of the study area where density of marked females was lower. A fourth analysis was conducted to compare breeding potential at actual and random lek locations, while controlling such biases. METHODS Greater prairie-chickens were studied in 1986-88 on a 301-knf study area centered 10 km northeast of Eckley, Colorado (40 II' N, 102 0 22' W). The area consisted of grassland, sand sagebrush (Artemisia filifolia), and small soapweed (Yucca glauca) intermixed with irrigated fields of agriculture, primarily corn. Locations of leks (2 or more displaying males) and maximum male attendance at each lek were determined each year. Estimates of male attendance were based on a minimum of 2 visits to each lek each year. Leks active during each year were considered 'permanent' and those 0 �103 active during only 1 or 2 years were considered 'temporary'. Trapping was concentrated on 16 leks within a core area of approximately Female greater prairie-chickens traps and cannon nets. 100 km2• were captured on leks using walk-in One to 15 females were captured on each lek. Captured females were banded with a numbered aluminum band and a unique combination of 3 colored plastic bands, and fitted with batteryor solar-powered radio transmitters attached to poncho-type markers (Arnstrup 1980). Radio weights ranged between 1.8 and 2.3% of each birds' body weight. Nests for radio-marked greater prairie-chickens were located using a portable receiver and 3-element Vagi antenna. All locations were recorded using Universal Transverse Mercator coordinates (nearest 10-m interval). Although home range size was not estimated directly, distance between each female's nest site and the lek where captured was used as an indirect measure of home range size. An estimate of breeding potential was used to evaluate the relative quality of given locations; breeding potential was defined as the proportion of distances between a given location and all. nest locations that were closer than observed distances between nests and lek-of-capture locations. Bradbury et al. (1986) suggested that pattern of male settlement in combination with overlap of female home ranges could be used to estimate the breeding potential at any given location. Breeding potential was defined as the proportion of distances between a given location and all nest locations that were closer than observed distances between nests and lek-~f-capture locations (Fig. 3-1). Breeding potential for a given location was calculated as: �104 OBSERVED DISTANCES * NEST o LEK BREEDING POTENTIAL 0/9 0/9 Fig. 3-1. Breeding potential for an example with 3 leks and 3 nesting females. Heavier shading represents higher breeding potentials (sample values are shown in some areas). �105 Breeding potential - n n I I Oq i-I j-l ,where n - number of females with known nest and lek-of-capture locations, . ~ - distance between nest location and lek-of-capture location for i-I, ••• , n females, ~ - distance between given location and j=l, ..., n nest locations, 0'1 - 0 if A, < 01, Oq - 1 if ~ > ~, and Oq - 0.5 if ~ • ~. The estimate of breeding potential resulted in values between 0 and 1. In the example (Fig. 3-1), breeding potential for males at the 3 leks shown (left to right) would be 2.5/9, 1.5/9, and 4.5/9. Larger breeding potentials reflect proximity to nesting females, whereas breeding potentials of about 0 should be expected for locations far from the study area. All simulations were done with Statistical Analysis System (SAS Institute 1985). Analysis 1 The initial analysis was conducted to estimate optimum lek locations based on 'peaks' in breeding potential, thus permitting comparison of optimum and actual lek locations (Bradbury et ale 1986). Optimum lek locations were identified by examining the breeding potential at grid nodes on the study area gridded by horizontal and �iUb vertical axes. Axes initially were separated by 0.1 km and subsequently refined to identify 'peaks' of breeding potential. 'Peaks' represented topographic rises in breeding potential of 0.001 from surrounding breeding potentials. Distances between locations of peaks in breeding potential and nearest actual lek locations were compared with distances between 100 random locations and nearest actual lek locations. Random locations were selected within a rectangular core of the study area bounded on all 4 sides by lek-of-capture locati~ns. The analysis was conducted with MRPP (Zimmerman et al. 1985, Biondini et al. 1988) for all 3 years combined. Analysis 2 The second analysis was conducted to compare breeding potential at .actual display sites with actual and simulated dispersions of females. In addition, the analysis permitted examination of the importance of breeding potential relative to lek size, lek stability (on a year-toyear basis), and trapping intensity. Breeding potential was first estimated for display sites on the study area in relation to nest locations of each female. Second, breeding potential was identified at the same display sites with 1000 randomly generated sets of nests. Each set of nests was generated by randomly selecting a distance from the actual set of nest-capture lek distances and a random direction for each female. Subsequently, simulated nest locations were identified with random directions and distances relative to each female's actual lek-ofcapture location. �107 In addition to comparison of breeding potential at leks with actual and simulated distributions of females (If tests), breeding potential at lek sites was examined (correlation) in relation to number of males attending the lek, number of females trapped at the lek, and year-to-year lek stability. Leks active in all 3 years were considered permanent, while leks active 1 or 2 years were considered temporary. All comparisons were conducted for each year separately. Analysis 3 The third analysis was designed for analyzing breeding potential at leks on the core portion of the study area only; most leks were in portions of the study area where no females were trapped. The breeding potential at leks where females were captured was estimated and compared with the breeding potential for the same leks with 1000 randomly generated sets of nests for each year (If tests). The mean breeding potential value for each set of data was weighted by the number of females captured at each 1ek. Each random set of nests was generated using the procedure from Analysis 2. Analysis 4 The fourth analysis was designed to compare breeding potential at actual and random 1ek locations with actual distributions of nests. Instead of eliminating biases associated with random number selection, this analysis used random dispersions of nests (as with Analysis 2) for estimating the size of the biases. For control, the breeding potential was examined at actual and random lek locations with random dispersions of nests. If there were no biases associated with selection of �locations, the breeding potential should not differ for actual and random lek locations with random distributions of nests. Experimental simulations consisted of actual and random lek locations with actual dispersions of nests. Comparison of experimental and control simulations was with a ~ contingency table. Random lek locations were chosen within the minimum rectangular core of the study area that . included all leks where females were captured. Analyses were conducted for each year separately. RESULTS Radios were placed on 36 adult and 56 yearling female greater prairie-chickens during the 1986-88 breeding seasons. different leks were on the study area during 1986-88. active from year-to-year; Sixty-five All leks were not 41, 42, and 47 were active during each breeding season, respectively. The distance between nearest neighboring leks was 1.31 ± 0.56 (!± SO), 1.20 ± 0.70, and 1.18 ± 0.62 km each year, respectively (medians of 1.42, 1.32, 1.15 km). Nest-Capture Lek Movements Females (n - 75) nested 0.2 to 29.1 km from leks where captured (Fig. 3-2). There was no apparent difference (f - 0.184) in movement attributable to year (General Linear Model with year and age as class variables). transformed Similar results were obtained when distances were log- (f - 0.111). Directions of movement for females between capture leks and nest sites were random ()( z 9.160; [8 45 categories]). 0 f = 0.241, OF = 7 �109 N 2 Fig. 3-2. 4 KM Distribution of distances and directions of movement for 75 female greater prairie-chicken nest sites and leks where each female was captured in northeastern Colorado, 1986-88. �110 Analysis 1 Seventeen possible lek sites were pinpointed at 'peaks' of breeding potential in the core of the study area (Fig. 3-3). Sites of peak breeding potential were surrounded by capture leks indicating that predicted lek locations may have been biased by trapping intensity. Overall, predicted leks were closer than random locations to actual leks. The mean distanc~ between predicted and nearest actual lek was 0.63 kID (SO - 0.40, n - l7). Only 1 of 100 distances between random locations and actual leks was smaller than 0.63 kID (X - 0.92; SO = 0.12); the 2 distributions were different (MRPP, f < 0.001). Since 11 of the actual leks closest to predicted leks were not permanent (active during only 1 breeding season), distances were also measured to permanent leks (X - 1.12, SO - 0.69). Only 7 of 100 distances between random locations and permanent leks were smaller than 1.12 kID (X - 1.31, SO ill 0.14); the 2 distributions were different (MRPP, f < 0.001). Analysis 2 Breeding potential was compared at all display sites with actual and random distributions of nests (Fig. 3-4). Most estimated lek breeding potentials were less for random nest dispersions than with actual nest dispersion (68.3% for 1986, 48.8% for 1987, 67.3% for 1988). If nest and lek dispersion were independent of each other, 50% of the lek breeding potentials with random nest dispersions should have been less than the breeding potentials with actual nest dispersions ()( = 12.075, f = 0.003). Breeding potential at display sites did not appear to be affected by male attendance (maximum number of males observed on each lek) for �III LEKS CAPTURE LEKS HYPOTHETICAL LEKS 60 :E" 55 l:t o Z ~50 ~ •••• ::l 45 15 20 25 30 UTM (KM EAST) Fig. 3-3. Contour lines for levels of breeding potential on greater prairie-chicken study. area in northeastern Colorado, 1986-88. �·~==========~· · · · ·· 1 301····· II 1986 (0=41) D [J 1987 (D=43) 1988 (D=55) ·~===========..· - ~20~ ·j ~ ~ 10 0-10 10-20 20-30 30-40 40-50 50·S0 SO-70 70-80 PROPORTION OF HIGH RANDOM VALUES (%) Fig. 3-4. Examination of breeding potential at actual display sites (n - 41 in 1986, n - 43 in 1987, n - 55 in 1988) with random distributions of females in relation to the breeding potential at the same display. sites with the actual distribution of females for greater prairie-chickens in northeastern Colorado, 1986-88. Proportion of high random values refers to the percentage of each set of random nests (n = 1000) resulting in higher breeding potentials at a given lek location than the actual distribution of nests. �113 1986 (~ < 0.001, f • 0.912), 1987 (~ • 0.003, f -0.752), and 1988 a (~2 • 0.004, f • 0.666). However, trapping success (number of females caught) appeared to improve breeding potential for 1986 (~2 • 0.014, f = 0.469), 1987 (~ • 0.002, f • 0.760), and 1988 (~ - 0.007, f - 0.534). There were no differences in breeding potential associated with lek stability (permanent or temporary) for 1986 (~ • 1.835, f - 0.176), 1987 (~ • 2.931, f • 0.087), and 1988 (~ - 0.231, f = 0.631). Analysis 3 The breeding potential at leks where females were captured was estimated and compared with the breeding potential for the same leks with 1000 randomly generated sets of nests for each year (Fig. 3-5). Although most simulated values were smaller than actual values, the results were not consistent for 1986 (~ • -495.616,f < 0.001), 1987 (~ • 3.364, f • 0.067), and 1988 (~ - 0.324, f • 0.569). Analysis 4 Breeding potential was compared for actual and random lek locations. The biases associated with selection of random locations on a fixed study area were obvious when the difference in breeding potential for random nest dispersions with actual and random lek dispersions was examined (Table 3-1). Despite biases, the proportion of breeding potentials smaller for random than actual leks with actual distributions of nests was smaller than control values (random vs. actual leks with random distributions of females) for 1986 (~ = 79.360, f < 0.001), 1987 (~ = 40.751, f < 0.001), and 1988 (~ = 69.929, f < 0.001). �114 30 _ . fit -en ~ 25 - o . [ill 20 - . Z . '.::::: ... o r-. t ::t !;;r 15 ..J ~ 1986 1987 1988 . ::~~~:: 10 ~- - i·· •• 1·-1········.·1········_··- --·--··---: 5 _._ •. _. __ ...- 1·· :••1·· •• •• 1J J-ll-"~i--.. :.::: .... ::. ':' ..,,::: ::.~.::~::.~.::~ .:.:. .:.:. l .t« .: :::: :. :::: .: :::: .: :::: :-::~ .: :::: r-r::J md ... ~.ua~ ....:~~~~.~.·~~m:~<~·:~~~.-~:·~~:I~:~·~ul~·: -a, O~~~~~· I I -I.s TO-1.0 . :: I I I I I -as TO-2.0 -1.5TO-1.0 ~.s TO0.0 :.:. I • :.:. :.:. I I 0.5TO1.0 • :.:• ITT 1.5TO2.0 I 2.5 TO3.0 I 3.5 TO4.0 DIFFERENCE IN BREEDING POTENTIAL Fig. 3-5. Examination of breeding potential at capture leks with 1000 random distributions of nests in relation to the breeding potential at the same leks with the actual distribution of nests for greater prairiechickens in northeastern Colorado, 1986-88. Difference in breeding potential refers to simulated breeding potential minus actual breeding potential. �115 Table 3-1. Simulated breeding potential for combinations of actual and random leks and nests (n • 1000 for each combination) for greater prairie-chickens in northeastern Colorado, 1986-88. Actual leks Random leks Random leks> Year Median ! SO actual leks (%) -• 0.243 0.247 0.059 9.60 0.284 0.030 0.222 0.223 0.044 24.60 0.185 0.185 -• 0.171 0.171 0.007 2.50 Random 0.182 0.184 0.034 0.169 0.170 0.039 9.20 Actual 0.330· 0.330 -• 0.325 0.325 0.006 .21.50 Random 0.332 0.043 0.330 0.328 0.047 38.65 Nests Median ! Actual 0.315 0.315 Random 0.283 Actual SO 1986 1987 1988 0.331 -Only 1 value was calculated for actual 1ek - actual nest combinations, hence no standard deviation was given. �DISCUSSION The results do not provide conclusive evidence the hotspot hypothesis is applicable to lek behavior in greater prairie-chickens. However, several results indicate that leks are in areas of relatively high female traffic. First, observations of visits to leks by females indicate that females usually fly to a lek from their approximate nesting area and return to their nesting area after leaving the lek. In addition, when the random nature of female movements from leks where they were captured to nest sites is considered, leks essentially are visited from all directions. Second, the breeding potential at most lek sites was higher with the actual dispersion of females than it was with random dispersions of females. Likewise, breeding potential at lek sites where females were captured gener~lly was higher with the actual dispersion of females than with a random dispersion of females. Finally, actual leks had a higher breeding potential than random leks. The selection of hotspots based on female nest sites and movements appeared to indicate that actual leks were not in the best areas. However, these results may have been biased by trapping intensity. Furthermore, distances between predicted and actual leks could not be compared with expected distances. These results fail to reject the hotspot ~ypothesis. One possible reason for the failure to reject may be the lack of adequate tests; in part, this may be caused by the circular nature of predictions associated with the hotspot hypothesis (Beehler and Foster 1988). Alternate procedures for examination of the hotspot hypothesis might include manipulation availability, of female traffic by alteration of food induced changes of intrasexual aggression among females, �117 or removals of males and/or leks. Furthermore, if local populations of males could be removed, settlement of replacement males on previously occupied sites could be used as support for the ability of males to assess the quality of a site (Warner 1988); considerations of quality could include the likelihood of en.countering females. LITERATURE CITED Amstrup, s. C. 1980~ 44:214-217. A radio-collar for game birds. J. Wildl. Manage. Beehler, B. M., and M. S. Foster. 1988. Hotshots, hotspots, and female preference in the organization of lek mating systems. Am. Nat. 131:203-219. Biondini, M. E., P. W. Mielke, Jr., and E. F. Redente. 1988. Permutation techniques based on euclidean analysis spaces: a new and powerful statistical method for ecological research. Coenoses 3:155-174. Bradbury, J',W. 1981. The evolution of leks. Pages 138-169 in R. D. Alexander and D. W. Tinkle. eds. Natural selection and social behavior: recent research and new theory. Chlron Press, New York, N.Y. ___ , and R. H. Gibson. in P. Bateson, ed. Cambridge, U.K. ___ , leks. 1983. Leks and mate choice. Pages 109-138 Hate choice. Cambridge Univ. Press, , and I. H. Tsai. 1986. Hotspots and the dispersion of Anim. Behav. 34:1694-1709. SAS Institute. 1985. SAS User's guide: statistics. SAS Inst., Inc., Cary, N.C. 956pp. Version 5 edition. Warner, R. R. 1988. Traditionality of mating-site preferences in a coral reef fish. Nature 335:719-721. Zimmerman, G. H., H. Goetz, and P. W. Mielke, Jr. 1985. Use of an improved statistical method for group comparisons to study effects of prairie fire. Ecology 66:606-611. �CHAPTER 4. GREATER PRAIRIE-CHICKEN MIGRATION IN NORTHEASTERN COLORADO INTRODUCTION Migration can be defined as na regular round trip within a lifespan of the individual" (Sinclair 1983:241). Tetraoninae patterns. lagoDus and Members of the subfamily are particularly variable with respect to migration While some species such as willow and rock ptarmigan (Lagopus l. mutus) are clearly migratory (Weeden 1964, Irving et ale 1967), most species are considered either partial- or non-migrants. Bl ue grouse (Dendragaoy.s obscyrys)(Wing .1. 1947, Mussehl 1960, Zwi ckel et 1968), spruce grouse (Dendr~gapys canadensis)(Herzog and Keppie 1980, Schroeder 1985), and white-tailed ptarmigan (Lagopus leucurys)(Hoffman and Braun 1975) display a partial migration in which some individuals migrate and others do not. Although blue grouse migration may be caused by elevational differences in habitat (Wing 1947, Mussehl 1960; Zwickel et al. 1968), spruce grouse migration has been attributed to fidelity to specific wintering and breeding areas and variabiliti in dispersal movements during their first spring (Herzog and Keppie 1980, Schroeder 1985). Greater prairie-chickens Tetraoninae, Hamerstrom are among the most mobile of the with seasonal movements to 170 km (Hamerstrom and 1949). Early reports indicated that greater prairie-chickens migrated between winter and breeding ranges; movements were suggested to be particularly extensive among females and typically related to habitat �119 (Gross 1930, Leopold 1931, Schmidt 1936, Hamerstrom and Hamerstrom 1949). Observations of large flocks moving north or south, skewed sex ratios among wlnter flocks, and seasonal increases or decreases in prairie-chicken movements. abundance have been cited as evidence of these migratory It has been hypothe~ized that introduction of corn· throughout the range of greater prairie-chickens resulted in the elimination of their migratory tendencies (Gross 1930). Patterns of movement may have important implications for the management of prairie-chickens. The appropriate timing of transplants to re-establish populations and management of blocks of habitat of restrictive sizes (Kirsch et al. 1973) both require an understanding of such movements. Additionally, extensive movements may have important effects on effective population size and/or genetic diversity of a population (Shields 1982). I examined timing and distance of seasonal movements by greater prairie-chickens in northeastern Colorado during 1986-89 with respect to sex, age, and reproductive status. The study area had both Wintering and breeding populations of prairie-chickens. Hence, there was no A priori reason to expect large movements between winter and breeding ranges by members of the population. Seasonal movements were described with respect to basic questions: 1) Are greater prairie-chickens migratory?, 2) Do females migrate farther and more frequently than males?, and 3) Do movements occur in response to factors such as habitat, natal dispersal, weather, and nesi failure? �120 METHODS A study area of 301 ~ 0 centered 10 km northeast of Eckley, Colo.rado (40 11' N, 102 22' W) was chosen for research on greater prairie-chickens. 0 The area consisted of grassland, sand sagebrush (Artemisia filifolia), and small soapweed (Yucca glauca) intermixed with irrigated fields of agriculture, primarily corn. The area contained 41-47 active leks (> 2 males on each) during each breeding season, 1986-89 (Chapter 2). Trapping was concentrated on a core area of approximately 75~. Trapping at winter feeding sites with walk-in traps baited with corn and at leks with walk-in traps and cannon nets resulted in capture of 243 different greater prairiechickens (Table 4-1). Since cannon nets were believed to cause more disturbance than other trapping methods, they were used sparingly and only in 1986. All captured birds were banded with a numbered aluminum band and a unique combination of 3 colored plastic bands. Age was ascertained by examining patterns of feather wear (Ammann 1944). Birds were classified as yearlings, 5-17 months of age (1 Nov of 1st year to 31 Oct of 2nd year), and adults, older than 17 months of age (after 31 Oct of 2nd year). Battery- and solar-powered radio transmitters were attached to poncho-type markers (Amstrup 1980) and placed on 145 greater prairiechickens (Table 4-1). Radio weights were between 1.8 and 2.3% of each birds' body weight. Seasons were defined j priori as breeding (15 Feb - 30 Jun), late summer (1 Jul - 15 Aug), autumn (16 Aug - 31 Oct), and winter (1 Nov 14 Feb); designation of seasons was based on aspects of breeding behavior and movement (Robel et al. 1970). Radio-marked greater �121 Table 4-1. Number of greater prairie-chickens captured, banded, and fitted with radio transmitters in 1986-89 in northeastern Colorado. Captures (including recaptures) Walk-in traps Category Bait sites Lek sites Cannon nets Totals Radios 76 86 21 183 34 Adults 32 56 14 102 20 Yearlings 44 30 7 81 14 52 132 6 190 III Adults 30 61 2 93 48 Yearlings 22 71 4 97 63 128 218 27 373 145 Males Females Totals �122 prairie-chickens Vagi antenna. were located using a portable receiver and 3-element Observations typically were obtained daily between 1 Mar and 15 Aug (sightings were up to 4 days apart during unusual circumstances). Occasionally, birds could not be found for periods up to 3 months; inevitably, when these birds were found, they had moved relatively long distances from locations where previously observed. The only exceptions were birds that were dead; some transmitters did not work for relatively long periods when they were partially buried in soil and/or vegetation. Aerial searches were conducted 2-3 times each year to locate missing transmitters. Locations for each sighting were obtained by direct visual observation (including nest sites) or by triangulation; 3 or more azimuths were obtained ~ 1.5 km of target transmitters and at angles-of-incidence greater than 35° and less than 145°. All locations were recorded using Universal Transverse Mercator coordinates (nearest lO-m interval). Examinations of accurac~ indicated that 90% of the locations derived by triangulation were within 250 m of actual locations (Chapter 2). Spring migration refers to winter - breeding season movements and autumn migration to breeding season - winter movements, regardless of the specific timing. Migration was estimated as the distance between the lek (males) or nest (females) location and the mean location (mean x and mean y coordinate) during the winter season. Additional movements were estimated using mean locations of late summer and autumn seasons as intermediate pOints between breeding and wintering areas; this procedure was used to help identify the specific timing of migratory movements. �123 Dates of movements were only estimated for distinct movements of ~ 5 km (clearly not part of the normal home range). Although arbitrary, the purpose of this procedure was to estimate the timing of migration, not the likelihood of migration. Furthermore, most movements meeting this criteria were distinct; birds often moved from the study area (~ 5 km) within 36 hours of being observed within their normal home range (females were often on or near their nest locations). In these cases, timing of movement was estimated based on searching intensity (time between searches) and/or the typical duration of a long migratory movement (2-4 days). For example, if a bird was located on 12 June, but not on or after 14 June, it was assumed to have migrated on 13 June. Statistical comparison of di~tributions of distances and dates was with Multi-Response Permutation Procedures (MRPP)(Zimmerman et a1. 1985, Biondini et a1. 1988). Comparisons of variances were conducted with f tests and comparisons of means with 1 tests, assuming unequal variances. RESULTS Timing of Movement The timing of distinct seasonal movements was recorded for greater prairie-chickens throughout the year (Fig. 4-1). The average date of spring migration was 27 March (SE - 6, n - 13) for females and 20 February (SE - 4, n - 3) for males; differences in averages (1 - 4.518, f - 0.001) and distributions (f - 0.002) were significant. The average date of aut~mn migration was 4 July (SE - 10; n - 33) for females and 28 July (SE 0.792, = 30, n= 5) for males; difference between the averages (1 = f = 0.464) and distributions (f = 0.520) were not significant. �124 7-----------6 ::::sc·Rrk~·1I1~CAT10"l·:::::. .... 1:' .•:t.•••. ",I. ~rnTJ 'T . ~s a: asu.4 o a: .......................... ........................... al ....................... ....................... W3 ::E ::>2 [] BROOD FEMALES E NON-BROOD FEMALES ~ MALES AUTUMN MIGRATION Z 1 1~ JAN 11 FEB II JAN 11 MAR lll'EII I "'ft II MAR 1 MAY .112APR 3.IUN .110MAY 1 JUL 17 JUN 21 JUL 15 JUL 21 AUG 12 AUG 25 11 SEP sat 23 OCT I OCT DATE (BEGINNING OF 2-WEEK PERIOD) Fig. 4-1. Distribution of movement dates for greater prairie-chickens in northeastern Colorado, 1986-89. �125 The tendency for males to move early to their respective 1ek areas was expected since leks were frequently active by mid-February. movements by females appeared to be bimodal. Much of this variability apparently was associated with the female's brood status. of migration was 10 June (SE • 9, n - 23) Autumn The mean date for females without broods and 26 August (SE - 19, n - 10) for females with broods (1 - 3.693, f 0.003). Similarly, differences associated with brood status were detected ()( - 9.989, f - 0.002) when the proportions of females migrating early and late were compared (separated by period between midJuly and mid-September when no migratory movements were observed, Fig. 4-1) • Many birds that apparently migrated were not observed during the winter or breeding seasons. This appeared to be due to mortality prior to the primary season of interest (winter or breeding season). Consequently, ~reeding season - winter distances were subdivided into breeding season - late summer and late summer - winter components. These distances were estimated only for females tracked throughout all seasons to provide additional information on the specific timing of movements (Fig. 4-2). These distances supported the finding that most long migratory movements occurred during May and June. For example, if many birds had movements for the 2 periods that were equal (along the 45 line), it would indicate that movements of many birds occurred 0 either throughout either season or during both seasons. -Most exceptions to the trend of early movements (May and Jun) were brood females; they tended to move toward winter ranges later than females without broods. The only brood female which moved a long distance early in the summer lost her brood within 2 days of hatch �::E 9 0 ~ BROOD FEMALES W 0 o NON·BROOD FEMALES D. ~ -a: en e C 0 0 D. W !z ;: 0 .~ I a: W s, 3 ::E ::E D. D. ~ :::> en- 0 c: 0 D. D. W 5 0 o 5 10 15 20 25 NEST - LATE SUMMER DISTANCE (KM) Fig. 4-2. Relationship between nest - late summer distances and late summer - .winter distances for female greater prairie-chickens northeastern ~olorado, 1986-89. in �127 (prior to movement). In general, movements between late summer and autumn ranges were relatively small for all females (Fig. 4-3). However, the 4 longest movements were by females with broods. Further support for timing of migration was obtained by examining dates of disappearance for radio-marked individuals that subsequently were not found (Fig. 4-4). Although some of these radios may have become disabled following mortality of the bird, the synchrony of disappearance dates with observed migration dates indicates that many radios may have been on birds that migrated but were not found. Hence, it is likely that estimates of migration tendencies and distances were low. Distance of Movement Fifty distances were recorded between winter and breeding areas for radio-marked greater prairie-chickens. Distances ranged between 0.64 and 39.98 km for females and 0.95 and 6.05 km for males (Fig. 4-5). These movements were treated as a continuum rather than categories in which migrants could be distinguished from non-migrants. Adult females moved an average of 8.20 km (SE - 1.73, n - 32), yearling females moved 14.39 km (SE - 5.90, 2.48 km (SE • 0.52, n • 3). n - 9), adult males moved and yearling males moved 3.52 km (SE = 0.75, Although yearlings of both sexes tended to move farther than adults, differences in distributions for females, £ • 0.289 for males). movements n - 6), (MRPP test) were slight (£ - 0.501 For both ages combined, female (!a 9.18 km, SE • 1.73) differed (MRPP test, male movements (!a 2.74 km, SE = 0.44). £= 0.019) from Distances for females typically were larger (1 - 3.600, £ - 0.001) and more variable (£ z �128 e,---------------~~--------------------------~ 5 • BROOD FEMALES [ill NON-BROOD FEMALES 1 o 0.0-0.5 0.5-1.0 1.0-1.5 1.5-2.0 2.0-2.5 2.5-3.0 3.0-3.5 3.5-4.0 DISTANCE (KM) Fig. 4-3. . Distribution of late summer - autumn distances for female greater prairie-chickens in northeastern Colorado, 1986-89. �129 o 5.--------------------------------------------------, [ill) Z BROOD FEMALES 11 NON-BROOD ~4 ~ FEMALES MALES Q. SPRING MIGRATION ~ ~3 AUTUMN MIGRATION BROOD FEMALES C en a: C -mu, 2 o a: ~1 :E ::::> z o 2SFEB 2SMAR 22APR 20 MAY 17JUN 16JUL 12AUG 11 SEP 1a0CT 11 MAR • APR 8 MAY JUN 1 JUL 21aJUL 28 AUG 25 SEP 23 OCT a DATE (BEGINNING OF 2-WEEK PERIOD) Fig. 4-4. Distribution of disappearance dates in relation to average date of migration (arrows) for greater prairie-chickens Colorado, 1986-89. in northeastern �12 en C a:: 9 . til FEMALES IT]. MALES [8J YEARLINGS al U. 0 a:: 6 W al ::E ::> z 3 o 0-2 4-6 2-4 8-10 12.•14 16-18 20-22 24-26 28-30 32-34 36-38 6-8 10-12 14-16 18-20' 22-24 26-28 30-32 34-36 ·38.40 DISTANCE (KM) Fig. 4-5. Distribution of distances between breeding and winter areas for 38 female and 12 male greater prairie-chickens in northeastern Colorado, 1986-89. �131 49.51, f < 0.001) than for males. Results for comparisons of distributions were similar when age groups were not combined (f = 0.048 for adults, f - 0.168 for yearlings). In addition, fewer male (0%, Fig. 4-6) than female (31.6%, Fig. 4-7) migrations crossed the study area boundary (~ - 4.986, f - 0.026). In addition to differences associated with migration distance and sex, movements were unusual with respect to their variability. Among females, both small and large distances were common, suggesting a bimodality in tendency to migrate. Furthermore, many individuals occupied winter or breeding areas on the main study area as the result of relatively large migratory movements (Fig. 4-7). Many females bypassed occupied habitats during the course of their movements. Analysis of migration distances (Figs. 4-5, 4-6, and 4-7) was conservati~e, only birds with known winter and breeding areas were included; this was despite the fact that migratory movements typically occurred during May and June. Consequently, many birds which died prior to a season of interest were not included in the analysis, even though many had obviously made long migratory movements. The analysis of movement data was expanded to additional birds, based on locations between breeding and late summer - winter areas (Fig. 4-8 for males, Fig. 4-9 for females). When the expanded analysis was conducted, females had an average migration distance of 10.58 km (n • 60) and males a distance of 2.86 km (n = 22, MRPP test, f < O.OOl)(Fig. 4-10). The distribution of distances supports the overall bimodality in migration tendency. Twenty-one of 60 females (35.0%) and 1 of 22 (4.5%) males migrated farther than 5 km; the difference between females and males was �132 4460 .. , N .. , .. , ::I: , : " ~ ,: 4455 ~ o i ...•, ~ z ::E ~4450 ::E ·S ?---i :'T'--"- _...,-_._.._' : ···-·--···-I··············'<:·-·-~~: i ~: -··l'~·:<~~:····--r·····---· '-T' - - rI ___ :_ 4445 . 715 : - •. I ---------------------~------. ,-720 725 730 735 UTM (KM EAST) Fig. 4-6. Straight-line distances between winter ranges (circles) and lek sites (asterisks) for 12 male greater prairie-chickens in northeastern Colorado, 1986-89. �133 N 4470 4460 ~ ~ 4450 a: o z - r ---. •• _~_ :E 4440 ~ - - - - - - ~ - - <I' 730 •••••••• 740 ,-------------- , ~ ~ 4430 ·························r··· . .. .... .. .. .. .. INSET •. 1 4420 4410 ---·r·----· I --..-- ··T-·.... 710 ....• .. ..• •. 1 1 .. .. .. ..• 1 .... 1- _ •• .. .. .. ,--------------------_. , ,, 720 UTM (KM EAST) Fig. 4-7. Straight~line distances between winter ranges (circles) and nest sites (asterisks) for 38 female greater prairie-chickens northeastern Colorado, 1986-89. .. in The inset shows females with both winter range and nest site on the study area. �4460 ''''... t .. , - N 'I :~ . ......... ··..·;..·.;··;;..··· ~;···..·····..~·r··· ···· ··· . ~4455 ct o Z ~ ~4450 ~ !5 4445 , I , , 705 710 715 720 725 730 735 UTM (KM EAST) Fig. 4-8. Straight-line distances between estimated winter ranges (circles) and lek sites (asterisks) for 22 male greater prairie-chickens in northeastern Colorado, 1986-89. �135 4470 4460 ~ ~ 4450 a: o z ~ 4440 730 .._.. ~ ,'-------------" , , ~ ~ 4430 :J 740 . .•. , ... INSET .•. , .•. I ...•. I ... , ... 4420 ..• I I .•. , .•.•. 4410 .• I I 1- _, ... .•. ... , .•. 710 ~-------------------_# 720 UTM (KM EAST) Fig. 4-9. Straight-line distances between estimated winter ranges (circles) and nest sites (asterisks) for 60 female greater prairiechickens in northeastern Colorado, 1986-89. The inset shows females with both winter range and nest site on the study area. , ,, �136 12 E FEMALES [J. MALES . en C a: 9 as LJ.. 0 a: 6 W £Xl :E ~ Z 3 0-2 . 4-6 8-10 12-14 16-18 20-22 24-26 28-30 32-34 36-38 40-42 44-46 OISTANCE (KM) Fig. 4-10. Distribijtion of migration distances for 60 female and 22 male greater prairie-chickens in northeastern Colorado, 1986-89. �137 significant ()( - 8.230, f - 0.004). The pattern of movement indicated there was no obvious relationship between direction of movement and tendency to move north or south prior to particular seasons (Fig. 4-11). Site Fidelity Site fidelity is important for distinguishing between regular migrations and nomadic movements (nomadic movements could be associated with unsuccessful ne~ting attempts). Of 6 radio-marked males monitored during consecutive years, all attended the same lek. An additional 10 banded males without radios were also observed on the same lek in consecutive years. Nest locations between consecutive years were an average of 0.S3 km (SE - 0.19, n - S) apart. The distributions of these distances were not different (f - 0.599) from distances (!- O.Sl km, SE - 0.11, n - 10) between first nests and re-nests within the same year (Fig. 4-12). There were no differences detected (MRPP) between males and females for fidelity between consecutive late summer (f - 0.440), autumn (f - 0.196), and winter (f - 0.070) ranges; the trend detected for the winter season was primarily caused by the late summer movements of a single yearling male. Sample sizes were too small to detect differences in fidelity associated with sex. differences With sexes combined, there were no between seasons (f • 0.629). Distances between consecutive winter ranges (based on mean location for each winter range) were relatively small (!- 1.0S km, SE - 0.33, consecutive late summer (!~ 1.30 km, SE (!- 1.99 km, SE - 0.79, n z n a 9) and distances between = 0.39, n = 7) and fall ranges 6)'were variable (Fig. 4-13). This �138 FEMALES N o MALES * o, o 48KM , , Fig. 4-11. Distribution of migratory movements by distance and direction for 60 female and 22 male greater prairie-chickens northeastern Colorado, 1986-89. movement of 4 km. in Each concentric circle represents a �139 5-,-----------.,. ·4 " CONSECUTIVE YEARS EJ FIRST AND RE-NESTS en c a: m3 u. o a: w CO2 :::E ::) z 1 o 0.0-0.2 0.2-0.4 0.4-0.S O.S-O.S 0.S-1.0 1.0-1.2 1.2-1.4 1.4-1.S 1.S-1.8 DISTANCE (KM) Fig. 4-12. Distribution of distances between nests during consecutive years and distances between first nests and re-nests within the same year for female greater prairie-chickens 89. in northeastern Colorado, 1986- �140 6,-----~~--------------------------------------~ Ii! LATE SUMMER [ill WINTER o AUTUMN 5 (J) ~4 CD U. 03 a: W CD :::e2 :::> Z 1 o 0-1 1-2 2·3 3-4 4·5 5·6 DISTANCE (KM) Fig. 4-13. Distribution of distances between late summer, autumn, and winter ranges during consecutive years for greater prairie-chickens northeastern Colorado, 1986-89. in �141 variability may have been caused by differences in timing of migration and brood status, rather than changes in site fidelity between years. Observations of Movements Due to speed and distance of many migratory movements, observations of actual movements were difficult to obtain (5 examples, Fig. 4-14). Three larger migrations (Fi%. 4-14A, B, and C) were typical of June migratory movements to winter ranges following nest predation. Female C made the movement within a 71-hour period and female B moved between her winter and breeding range within a 137-hour period. Female C was of interest for 3 additional reasons: 1) her first movement between her winter area and nesting area may have been a dispersal movement (she was a yearling), 2) her subsequent return to the same general winter area may indicate that migration movements may mirror dispersal movements, and 3) she wintered on the same general area in which females A and B spent the breeding season. While many of the characteristics of movement and/or disappearance patterns were consistent with the hypothesis that migrations were relatively fast and direct, 2 movements were notable because of their unpredictability. One female (Fig. 4-140) was observed during an early June migration of approximately 8 days and 13.4 km. It is doubtful that this movement was typical, since most migratory birds disappeared the study area within a 36-hour period. from Another female (Fig. 4-14E) appeared to change winter areas during winter (late December). Her new area was closer to her breeding area, indicating the possibility that some females may not display site fidelity to their winter areas. �142 N B 4470 \ \ 4460 ,------- --, , , ,, , I •. • I I ,, I ----------------' 4430 * NEST LOCATION o WINTER RANGE o TRANSITIONAL LOCATION 4420 710 720 730 740 750 UTM (KM EAST) Fig. 4-14. northeastern Seasonal movements of 5 female greater prairie-chickens Colorado, 1986-89. in �143 DISCUSSION Results from this study clearly indicated that greater prairiechickens in northeastern Colorado are partially migratory; some individuals move sUbstantial distances (up to 40 km) between seasonal ranges while others remain resident on relatively small areas. In addition, 95.5% of 22 males and 65.0% of 60 females migrated < 5 km indicating that females are more likely to migrate than males. Last, observations of direction, timing, and behavior associated with movement indicated that movements apparently were not caused by differences habitat, weather, and nest failure. in The possibility that migratory movements may retrace a bird's dispersal movement between its first wintering and breeding area was not rejected. Askins (1913) suggested that greater prairie-chickens. were -basically non-migratory. In contrast, several lines of evidence have been used to suggest that greater prairie-chickens were historically migratory in portions of their original and acquired range (Gross 1930, Leopold 1931). Grange (1948) considered evidence for regular migrations prior to 1850 as 'indisputable'. First, seasonal increases and decreases in population size were noted in both southern and northern parts of the range. Second, evidence of biased sex-ratios in resident and/or migratory populations has been used to demonstrate migratory tendencies. Finally, large flocks of greater prairie-chickens have been observed making directional movements and/or in areas with no acceptable habitat. Data from banded and radio-marked individuals also has provided support for seasonal movements. Seasonal changes in regional populations of greater prairiechickens have often been used as evidence of migrations. For example, �winter increases have been observed in several locations where greater prairie-chickens were either absent (Bogardus [1874] for central Illinois; Leopold [1931] for Ames, Iowa; Webster [1912] for Charles City, Iowa, and Manitowoc County, Wisconsin; Stempel and Rodgers [1961] and Spengler [1984] for southwestern Iowa) or less abundant (Cooke [1888] for southern Iowa, northern Missouri, and southern Illinois; Judd [1905] for Kentucky; Leopold [1931] for Trempealeau County, Wisconsin; and Schmidt [1936] f~r Oklahoma, Texas, Arkansas, Missouri, southern Illinois, and eastern Kansas) during the breeding season. Similar population changes have been noted during the breeding season in areas where birds were either absent (Leopold [1931] for Forest County, Wisconsin and North Dakota and Banta [1892] for northeastern Minnesota) or less abundant (Cooke [1888] and Leopold [1931] for northern Iowa and. southern Minnesota) during the winter. A bias in sex ratio during winter has been used as evidence confirming migratory tendencies of greater prairie-chickens, in particular. - and females For example, of the few birds remaining in North Dakota during winter, all were reportedly males (Leopold 1931). Likewise, Schmidt (l936) found a male:female ratio of 121:16 in northern Wisconsin and 49:272 in southern Wisconsin. Cooke (1888) suggested that females migrate farther and more frequently than males. Unfortunately, problems associated with accurate identification of sex ratios in winter flocks have made adequate examinations of regional movements difficult. Stronger evidence for a sex bias in movement tendencies has been gathered with banding and radio-telemetry Hamerstrom studies. Hamerstrom and (1949) found that females migrated farther and more frequently than males in Wisconsin. The longest migration distance �145 recorded for Wisconsin was about 170 km for a female (Hamerstrom and Hamerstrom 1949). In addition, 41.8% of 134 males and 4.7% of 107 females banded during winter were observed on the same area in spring. When distances between winter and breeding areas were examined, 32.2% of 298 distances for females and 4.9% of 834 distances for males were> km. 8 In North Dakota, 15 females moved 4.3 km and 6 males moved 2.6 km on average between winter and breeding season (Toepfer and Eng 1988). Evidence from this study demonstrated similar patterns of movement; 95.5% of 22 males and 65.0% of 60 females migrated < 5 km. Larg~r distances and frequency of movement by females was consistent with patterns of movement documented for other grouse including spruce grouse (Herzog and Keppie 1980, Schroeder 1985, 1986), blue grouse (Hines 1986), sharp-tailed grouse (Tympanuchus phasianellus) .(Kobriger 1965), sage gr9use (Centrocercus urophasianus)(Beck white-tailed 1977), ptarmigan (Hoffman and Braun 1975), rock ptarmigan (Weeden 1964), and willow ptarmigan (Weeden 1964, Irving et al. 1967). Although reasons for more extensive movement by female than by male Tetraoninae are not known, possible factors may include sex differences intraspecific competition in (Herzog and Keppie 1980), habitat selection (Gross 1930, Schmidt 1936), and inheritance (Keppie 1980, Schroeder 1988). Gross (1930) and Leopold (1931) examined anecdotal evidence for several hypothesized migrations including observations for South Dakota; Burlington, Iowa; northeastern Minnesota; Door County, Wisconsin; Ripley County, Missouri; and Peoria County, Illinois. in Burlington, The migratory movements Iowa apparently were predictable enough that hunters were able to prepare for them. �146 Migratory tendencies possibly were reduced with the introduction of corn throughout northern parts of greater prairie-chicken (Hamerstrom and Hamerstrom 1949). range Even so, planted food patches in Wisconsin failed to prevent birds from migrating (Grange 1948). Unfortunately, migrations. little information is available on pre-settlement Cooke (1888) suggested that migratory movements were as long as 1,000 km before corn was introduced. Stempel and Rodgers (1961) suggested that birds wintering in southwestern to have migrated at least 160 km. Iowa into the 1960's had Neither example can be verified. Data from Hamerstrom and Hamerstrom·(1949) for banded individuals in Wisconsin has shown that movements can be substantial movements were 46 and 170 km for females). in Minnesota (2 largest Migratory movements of 12 km (Svedarsky 1988) and 30 km in Michigan (Ammann 1957) have also been observed for females. Movements up to 40 km were observed in this study; whereas many individuals were essentially resident on one area, others moved relative long distances between breeding and wintering areas. It was impossible to detect any differences between patterns of migration observed in this study and patterns described in previous research. Most migratory movements of greater prairie-chickens occur during October-December and Hamerstrom March-April Occasionally, in autumn (Leopold 1931, Lehmann 1939, Hamerstrom 1949, Mohler 1952, Ammann 1957) and in spring during (Leopold 1931, Hamerstrom and Hamerstrom 1949). movements may be as early as August (Leopold 1931). However, none of the examples of migratory movements was documented with observations \ of banded individuals. �147 Data collected on radio-marked birds in this study indicated the timing of migration may be relatively complicated. movements occurred in February-April Although spring (males earlier than females), autumn movements occurred as early as late-May. Examination of movements by females indicated that timing of autumn movements may be bimodal; brood females moved during October-November and unsuccessful females typically moved during June. The early timing of most autumn migrations by greater prairiechickens appears to be unusual for grouse. Most species appear to move during late summer or autumn (Irving et a1. 1967; Zwicke1 et a1. 1968; Hoffman and Braun 1975; Schroeder 1985, 1986). possibility that greater prairie-chickens, This raises the particularly females without broods, are migrating prior to the normal summer molt period. supported by bimodality in movement timing. Females with broods may wait until after the molt before undertaking long movements. period may be important for prairie-chickens often long, necessitating This is The molt since their movements are at least some flying. In contrast, spruce grouse have been observed walking on their migratory routes (Schroeder 1985). Variability in migration timing, sex ratios, and distance has resulted in several possible explanations for movements. First, movement in response to regional food availability has been a common explanation for migration of greater prairie-chickens (Cooke 1888, Gross 1930, Leopold 1931, Lehmann 1939, Hamerstrom and Hamerstrom 1949, Mohler 1952, Ammann 1957, Toepfer and Eng 1988). Second, Banta (1892) suggested that large flocks of greater prairie-chickens 1875-8 may have been fleeing from hunters. in Duluth in Third, Leopold (1931) and �148 Hamerstrom and Hamerstrom (1949) suggested that tendencies to migrate varied with weather. Data from radio-marked birds in this study both contradicted and supported many of the previous suggestions: 1) the prevalence of early movements (most in mid-summer) indicated that weather was not a major driving force, 2) movements were typically in random directions, birds were just as likely to. move north as south prior to winter, 3) many birds moved onto the same areas that other birds moved from, 4) some individuals remained on the same areas during winter and summer while others migrated, and 5) females migrated more frequently and farther than males. When these observations were considered in combination with the general availability of corn throughout the region (typical winter food), habitat was ruled out as an adequate explanation for the observed movements. Svedarsky (1988) suggested that many of the long movements by females may be due to disturbances by predators at nest sites; this explanation Colorado. could be considered for greater prairie-chickens in However, although female migrations frequently were made following nest failure (Fig. 4-1), females regularly returned to their previous nesting areas, despite nest failure. Likewise, females producing broods also migrated, even though their movements were later during autumn or early winter. Some exceptions may be explained by either late re-nesting attempts (late migration by a female without a brood) or early brood loss (early migration by a female with a brood). Although sample sizes for males were small, males apparently approached their winter ranges following the breeding season (late May - Jun). The �149 timing of male movements appeared to be closely tied to their attendance at leks. Males often displayed at leks until mid-June. One possible explanation for migration is that migratory movements mirror dispersal movements; birds may disperse between their place of hatch and breeding area while displaying fidelity to both their first wintering and breeding areas. A similar type of dispersal phenomenon has been noted for blue grouse (Hines' 1986) and spruce grouse (Herzog and Keppie 1980, Schroeder 1985, 1988). Henc~ it would be difficult, if not impossible, to differentiate between the causes of dispersal and migration~ Similarity between patterns of dispersal and migration may be especially important, given the context of most observations of largescale migrations. , recorded,during Consequently, Many .observations of migratory movements were periods of rapid range expansion (late 1800's). it may be possible that migrations of greater prairie- chickens have not consisted of more than local movements in response to habitat availability in combination with dispersal tendencies and fidelity to wintering/breeding sites. The similarity between adult and yearling patterns of movement for females indicated that migratory movements of adults may mirror the dispersal movements of yearlings ,during their first spring (as noted with spruce grouse; Herzog and Keppie 1980, Schroeder 1985). This may help explain the· female bias in movement that is consistent with most patterns of dispersal in birds (Greenwood and Harvey 1982). LITERATURE CITED Ammann, G. A. 1944. Determining the age of pinnated and sharptailed grouses. J. Wildl. Manage. 8:170-171. . �___ • 1957. Lansing. The prairie grouse of Michigan. 200pp. Michigan Oep. Conserv., Amstrup, S. C. 1980. A radio-collar for game birds. Manage. 44:214-217. Askins, C. 1913. The prairie chicken. Banta, D. D. 1892. 39:443. J. Wildl. Field and Stream 18:634-641. A prairie chicken migration. For. and Stream Beck, T. D. I. 1977. Sage grouse flock characteristics and habitat selection in winter .. J. Wildl. Manage. 41:18-26. Biondini, M. E., P. W. Mielke, Jr., and E. F. Redente. 1988. Permutation techniques based on Euclidean analysis spaces: a new and powerful statistical method for ecological research. Coenoses 3:155-174. Bogardus, A. H. 1874. Field, cover, and trap shooting. Co., New York, N.Y. 343pp. J. B. Ford and Cooke, W. W. 1888. Report on bird migration in the Mississippi Valley in the years 1884 and 1885. U.S. Dep. Agric., Div. Econ. Ornith., Bull. 2. 313pp. Grange, W. B. 1948. Oep., Madison. Wisconsin grouse problems. 318pp. .. Wisconsin Conserv. Greenwood, P. J., and P. H. Harvey. 1982. Natal and breeding dispersal of birds. Annu. Rev. Ecol. Syst •.13:1-21. .Gross, A. O. 1930. Progress report of the Wisconsin prairie chicken investigation. Wisconsin Conserv. Comm., Madison. 112pp. Hamerstrom, F. N., Jr, and F. Hamerstrom. 1949'- Daily and seasonal movements of Wisconsin prairie chickens. Auk 66:313-337. Herzog, P. W., and D. M. Keppie. 1980. Migration in a local population of spruce grouse. Condor 82:366-372. Hines, J. E. 1986. Recruitment of young in a declining population of blue grouse. Ph.D. Oiss., Univ. Alberta, Edmonton. 256pp. Hoffman, R. W., and C. E. Braun. 1975. Migration of a wintering population of white-tailed ptarmigan in Colorado. J. Wi1dl. Manage. 39:485-490. Irving, L., G. C. West, L. J. Peyton, and S. Paneak. 1967. Migration of willow ptarmigan in arctic Alaska. Arctic 20:77-85. Judd, S. D. 1905. The grouse and wild turkeys of the United States and their economic value. U.S. Bur. Bio1. Survey Bull. 24. 55pp. �151 Keppie, D. H. grouse. 1980. Similarity of dispersal among sibling male spruce Can. J. Zool. 58:2102-2104. Kirsch, L. H., A. T. Kleff, and H. W. Hiller. 1973. Land use and prairie grouse population relationships in North Dakota. J. Wildl. Hanage. 37:449-453. Kobriger, G. D. 1965. Status, movements, habitats, and foods of prairie grouse on a sandhills refuge. J. Wildl. Manage. 29:788800. Lehmann, V. W. 1939. The heath hen of the south. Oyster Comm., Bull. 16. Ilpp. Texas Game, Fish and Leopold, A. 1931. Report on a game survey of the North Central States. Am. Game Assoc., Madison, Wisc. 299pp. Hohler, L. L. 1952. Fall and winter habits of prairie chickens in southwest Nebraska. J. Wildl. Manage. 16:9-23. Hussehl, T. W. 1960. Blue grouse production, movements, and populations in the Bridger Mountains, Montana. J. Wildl. Manage. 24:60-68. Robel, R. J., J. N. Briggs, J. J. Cebula, N. J. Silvy, C. E. Viers, and P. G. Watt. 1970. Greater prairie chicken ranges, movements, and habitat usage in Kansas. J. Wildl. Manage. 34:286-306~ Schmidt, F. J. W. 1936. Winter feed of the sharp-tailed grouse and pinnated grouse in Wisconsin. Wilson Bull. 48:186-203. Schroeder, H. A. 1985. Behavioral differences of female spruce grouse undertaking short and long migrations. Condor 87:281~286 • .' ______ • 1986. The fall phase of dispersal in juvenile spruce grouse. Can. J. Zool. 64:16-20. ______ • 1988. Dispersal in spruce grouse: is inheritance involved? Anim. Behav. 36:305-308. Shields, W. M. 1982. Philopatry, inbreeding, and the evolution of sex. State Univ. New York Press, Albany. 245pp. Sinclair, A. R. E. 1983. The function of distance movements in vertebrates. Pages 240-258 in I. R. Swingland and P. J. Greenwood, eds. The ecology of animal movement. Clarendon Press, Oxford, U.K. Spengler, R. 1984. Greater prairie chicken in Osceola County. Bird Life 54:21. Iowa Stempel, M. E., and S. Rodgers, Jr. 1961. History of prairie chickens in Iowa. Proc. Iowa Acad. Sci. 68:314-322. �152 Svedarsky, W. chickens Gratson, northern O. 1988. Reproductive ecology of female greater prairie in Minnesota. Pages 193-239 in A. T. Bergerud and M. W. eds. Adaptive strategies and population ecology of grouse. Vol. I. Univ. Minnesota Press, Minneapolis. Toepfer, J. E., and R. l. Eng. 1988. Winter ecology of the greater prairie chicken on the Sheyenne National Grasslands, North Dakota. Pages 32-48 in A. J. Bjugstad, Tech. Coord. Prairie chickens on the Sheyenne National Grasslands. u.S. Oep. Agric. For. Servo . Gen. Tech. Rep. RM-159. Webster, C. l. 1912. Winter migration of the prairie chicken. and Stream 78(15):471. For. Weeden, R. B. 1964. Spatial segregation of the sexes in rock and willow ptarmigan. Auk 81:534-541. Wing, l. 1947. Seasonal movements of the blue grouse. Wildl. Conf. 12:504-510. Trans. No. Am. Zimmerman, G. M., H. Goetz, and P. W. Mielke, Jr. 1985. Use of an improved statistical method for group comparisons to study effects of prairie fire. Ecology 66:606-611. Zwickel, F. C., I. o. Buss, and J. H. Brigham. 1968. Autumn movements .of blue grouse and their relevance to populations and management. J. Wildl. Manage. 32:456-468. �153 APPENDIX A. WALK-IN TRAPS FOR CAPTURING GREATER PRAIRIE-CHICKENS IN NORTHEASTERN COLORADO EXAMINATION OF TECHNIQUE Numerous techniques have been used for capturing greater prairiechickens (Tympanuchus cupido) including cannon nets'(Silvy and Robel 1967, 1968, Arthaud 1968, Robel et al. 1970), mist nets (Silvy and Robel 1968, Robel et al. 1970), helicopters (McCune 1970, Brown 1981), drop nets (Jacobs 1958), bownets (Anderson and Hamerstrom 1967, Robel et al. 1970), noose carpets (Berger and Hamerstrom 1962), drop-nets (Jacobs 1958, 1959, 1964, Arthaud 1968), dip-nets (Arthaud 1968), night-lfghting w~th hand-nets (Robel et ai. 1970), and walk-in traps (Berger and Hamerstrom 1962, Hamerstrom and Truax 1938, Robel et al. 1970, Hamerstrom and Hamerstrom 1973, Horak 1985, Toepfer et al. 1988). of the techniques include modifications Many such as trap placement (leks, bait sites, and travel corridors), trap design, use of hen decoys (Anderson and Hamerstrom 1967), and male vocal izations (Sllvy and Robel 1967). Other than Toepfer et al. (1988), little has been documented about specific use of walk-in traps at lek sites. The objective of this paper is to document the design and effectiveness northeastern of walk-in traps used at greater prairie-chicken Colorado. leks in Although Toepfer et al. (1988) documented a similar trap design for greater prairie-chicken different type of funnel. leks, they used a �154 Walk-in traps were made with 6' X IS" (15.2 X 45.7 cm) sections of 2" X 4" (5.1 X 10.2 cm) welded wire. Thus, approximately 32 traps could be made from a 100' (30.5 m) roll of 3' (91.4 cm) wide wire. By cutting the roll in half lengthwise, each trap had a series of 2n points that could be imbedded in the'ground. 1" chicken-wire (Fig. A-I). A funnel was made for each trap with Funnels were specifically designed so that most exposed points (places where the wire was cut) were on the bottom of the funnel. Other exposed wire points should be bent into positions that reduce the probability of captured birds contacting them. Funnels were fitted between the ends of each cut section welded wire. Each trap was covered with nylon net that could be opened near the trap edge to retrieve captured birds. Each walk-in trap was arranged with chicken-wire leads to maximize the potential for capturing birds. wUh All traps and leads were secured metal stakes pushed into the ground. Traps generally were placed in areas of highest prairie-chicken activity; these locations were determined through observation or by examination of concentrations droppings and feathers. used (Fig. A-2). of Several basic designs of traps and leads were Some traps were oriented such that birds were likely to encounter the trap when walking toward the center of the lek and others were positioned so that birds would encounter traps when walking away from the center of the lek. orientation Although definitions of trap (inward, neutral, and outward) were arbitrary, they enabled the relative effectiveness of different trap orientations to be compared. A total of 1,970 trap days (each funnel counted as a trap) were used to capture 231 birds (Table A-I). Females were captured more �155 c D A B 32 INCHES (81.3 MM) ,15 INCHES (38.1 MM), T e INCHES (15.2 MM)l Fig. A-I. 11 INCHES ENTRANCE EXIT (27.9 MM) BOlTOM Funnel design for greater prairie-chicken walk-in traps in northeastern Colorado, 1986-89. To construct, similar letters should be conected, dashed lines should be folded, and exposed points should be blunted. �156 '* •••• I , '----, .•. "-~- .•. .. , , ,, ,," .. , .. ' .-:::-"-~ ": '__ - -- . ... .. " , , o .. .•. ...•.. ~ ' ,, " (3:' .•. .. .•. .•. '_---- ..•." .•. .•. ... " ,, '" , .._-~ , ., '. @'".~' , ' I \ I \ tr -,•._... _.,tp.. \ .. ,.. " ,- _ ~ Gl I... I .- ' ••• "* •• , .... containing -- \ I I , ,, ,r " " .. 6'- ...•. ..._-£) ,, I , ,, , .. ~ ••• I Typical arrangements of walk-in traps and 18" high chicken- wire leads (dashed lines) for capturing greater prairie-chickens northeastern '' . e,.-,--' '..' ..._"NL._ \ e- - - _, ,, ,I r I t9 , ,, , ,, I ,, I , I , Fig. A-2. ...• 20M , .•. I -, ~__--8 , 10 I .•. ,, ,, , - .•. I I ", , .',' •. \ ,, I ...•:9-- ... _ .• -.. \ ,•, 1 ,'" Colorado, 1986-89. Two types of traps were used: 1 a Single funnel and the other containing 4 funnels. in .•. ,, �157 Table A-I. Trap success of male and female greater prairie-chickens relation to trap orientation in northeastern Colorado, 1986-89. in Funnel openings were pOinted toward the center of the lek (inward), away from the center of the lek (outward), or with no particular direction (neutral) . Category Trap days Males Females Total Number Percent Number Percent Number Percent Inward 753 25 3.32 35 4.65 60 7.97 Outward 425 26 6.12 36 8.47 62 14.59 Neutral 792 48 6.06 61 7.70 109 13.76 1970 99 5.03 132 6.70 231 11.73 Total �frequently than males in these traps ()( - 5.008, f - 0.025). In addition, the 3 orientations of traps were variable with respect to proportion of males ()( - 7.055, 0.048) trapped. f - 0.070) and females ()( - 7.907, f • Both sexes apparently were more difficult to catch in traps facing inward. Finally, time of year appeared to be more important for capturing females than for males (Fig. A-3). Females easily could be caught during 5-20 April, while males could be captured throughout the breed~ng season. The methods proposed herein can be modified. Observations at leks can be used to determine the effectiveness of the trap design and arrangement of traps on leks. Funnels were modified several times to increase either the likelihood of a bird entering and/or the probability of the bird remaining in the trap. In addition, effectiveness of traps for capturing males and/or females apparently was improved with movement of traps and chicken-wire leads on leks. The effectiveness of these techniques for capturing males and females could not be compared since the abundance of either sex was not known. Walk-in traps have several advantages over other trapping methods. Unlike most other trapping techniques, walk-in traps can be set at several locations at the same time. In addition, the lack of continuous attendance by researchers minimizes disturbance, especially if traps are . positioned in a manner that permits them to be monitored from relatively long distances. modify. Finally, walk-in traps are inexpensive to make and/or. Traps of this basic design also have been used to capture lesser prairie-chickens, Colorado. sharp-tailed grouse, and sage grouse in �159 15 Ii MALES Ifill -fa FEMALES 12 ~ Cf) 9 8 :J Cf) 8 ~ 3 ""7 1-11 12·16 11-11 20023 24-27 28-31 104 MAR Fig. A-3. loa 1012 13011 17·20 21·24 25028 >28 APR Distribution of greater prairie-chicken trapping success during the breeding season in northeastern Colorado, 1986-89. �160 LITERATURE CITED Anderson, R. K., and F. Hamerstrom. 1967. Hen decoys aid in trapping cock prairie chickens with bownets and noose carpets. J. Wildl. Manage. 31:829-832. Arthaud, F. l. 1968. Populations of the prairie chicken related to land use in southwestern Missouri. M.A. Thesis, Univ. ,Missouri, Columbia. 134pp. Berger, D. D., and F. Hamerstrom. 1962. Protecting a trapping station from raptor predation. J. Wildl. Manage. 26:203-206. Brown, D. l. 1981. The helinet: a device for capturing prairie chickens and ring-necked pheasants. Proc. S. E. Assoc. Fish Wildl. Agencies 35:92-96. Hamerstrom, F. N., Jr., and M. Truax. 1938. Traps for pinnated and sharp-tailed grouse. Bird-Banding 9:177-183. Hamerstorm, F. N., Jr., and F. Hamerstrom. 1973. The prairie chicken in Wisconsin. Highlights of a 22-year study of counts, behavior, movements, turnover and habitat. Dep. Nat. Resour., Tech. Bull. 64. 52pp. Horak, G. J. 1985. Kansas prairie chickens. Comm., Wildl. Bull. No.3. 65pp. Kansas Fish and Game ' Jacobs, K. F. 1958. A drop net trapp~ng technique for greater prairie _ chickens. Proc. Oklahoma Acad. Sci. 38:154-157. ______ ,. 1959. Restoration of the greater prairie chicken. Oklahoma Dep. Wildl. Cons., Div. Fed. Aid Wildl. Restoration Proj. W-65-R. 42pp. ______ • 1964. An electrically actuated release mechanism for dropnets. Proc. Annu. Conf. Southeastern Assoc. Game Fish Comm. 18:30-34. McCune, R. A. 1970. Prairie chicken moving days. Wildl. 28(7):12-15. Texas Parks and Robel, R. J., J. N. Briggs, J. J. Cebula, N. J. Silvy, C. E. Viers, and P. G. Watt. 1970. Greater prairie chicken ranges, movements, and habitat usage in Kansas. J. Wildl. Manage. 34:286-306. Silvy, 'N. J., and R. J. Robel. 1967. Recordings used to help trap booming greater prairie chickens. J. Wildl. Manage. 31:370-373. ______ , and . 1968. Mist nets and cannon nets compared for capturing prairie chickens on booming grounds. J. Wildl. Manage. 32:175-178. �161 Toepfer, J. E., J. A. Newell, and J. Monarch. 1988. A trapping prairie grouse he~s on display grounds. A. J. Bjugstad, Tech. Coord. Prairie chickens on National Grasslands. U.S. Oep. Agric. For. Servo RM-159. method for Pages 21-23 in the Sheyenne Gen. Tech. Rep. �162 APPENDIX B. LEK PERSISTENCE AND ATTENDANCE OF MALE GREATER PRAIRIECHICKENS IN NORTHEASTERN COLORADO INTRODUCTION Many species of Tetraoninae congregate on leks for breeding purposes including sage grouse (Centrocercus urophasianus), grouse (Tymoanuchus ohasianellus), pallidicinctus), sharp-tailed lesser prairie-chickens and greater prairie-chickens. (Tympanuchus Density of leks and attendance of males at leks have both been used as indices to overall status of their populations (Cannon and Knopf 1981). Despite frequent use of such indices, little. is known about male attendance at leks and the stability, consistency, and/or distribution of leks. Previous research on greater prairie-chickens suggested that only about 50% of males attend leks on any given day (Robel 1970). Robel's (1970) conclusions were based on capture of males on 3 leks and subsequent observation of marked males on the same leks. His data did not include observations of marked males captured off leks. Also, Robel (1970) did not track radio-marked males during peak breeding periods eliminating the possibility of observing males at locations other than the 3 lek sites. Similar research on sage grouse suggested that although visitation rates may be relatively high (approximately 90%), vistation may depend on time of year (Emmons and Braun 1984). Miller (1984) suggested that 41.5% of greater prairie-chicken disappeared between any 2 years. leks However, these conclusions were based �163 on 3 years of research on the edge of occupied range eliminating the possible differentiation between permanent and temporary leks (referred to as dominant and satellite leks, respectively, by Hamerstrom and Hamerstrom [I973]). This latter factor is particularly important because of Cannon and Knopf's (I98I) suggestion that lek densities adequately represent population trends because of the formation of satelite leks by subordinate males. Greater prairie-chickens are a useful subject for research on the dynamics of males and/or leks; (I) they can be captured during the winter to reduce biases associated with lek captures, (2) they can be monitored with radio-telemetry, monitored. and (3) all leks can be located and This paper documents the attendance at leks of radio-marked male greater prairie-chickens and the stability and distribution of leks. METHODS A study· area of 301 knf, centered 10 km northeast of Eckley, Colorado (40 II' N, 102 22' W) was monitored in 1986-90 to estimate 0 0 lek density and male lek attendance for greater prairie-chickens. additional 631 knf peripheral area was added in 1988. displaying males were considered a lek. An Two or more Attendance for each lek (within a year) was estimated by using the maximum of at least 2 counts of males at each site. Males, at leks were counted during March, prior to visitation by females. Leks were defined as 'persistent' (active during all previous years of research, 'permanent' (active during all 5 years of research), 'additional' 'temporary' (inactive at least 1 year), and/or (not described in previous years). �164 Trapping was concentrated on a core area of approximately during 1986-88. Male greater prairie-chickens 100 km2 were captured on winter feeding sites using walk-in traps baited with corn and on leks using walk-in traps and cannon nets. Captured males were banded with a numbered aluminum band and a unique combination of 3 colored plastic bands, and fitted with battery- or solar-powered radio transmitters attached to poncho-type markers (Amstrup 1980). Radio weights' ranged between 1.8 and 2.3% of each birds' body weight. yearlings Birds were classed as (first breeding year) or adults (> first breeding year) (Ammann 1944). Observations of 20 adult and 14 yearling radio-marked males were gathered between 0.5 hours before t9 2.0 hours after sunrise during 1 March-30 April, 1986-88; these dates were chosen to adequately represent the normal display season for males of 15 FebruarY-IS May. Radio-marked greater prairie-chickens were located using a portable receiver and 3-element yagi antenna. Observations of birds consisted of visual signtings of radio-marked males on leks (usually from 0.2 to 1.0 km away) and/or triangulation target transmitters (3 or more azimuths obtained ~ 0.5 km of and at angles-of-incidence greater than 35° and less than 145°. All locations were recorded using Universal Transverse Mercator coordinates Examinations (nearest 10-m interval). of accuracy indicated that 90% of the locations derived by triangulation 2). were within 250 m of actual locations (Chapter Even so, differentiation leks were relatively distinct. between observations of males on and off Radio-telemetry was used to estimate locations of radio-marked males before leks were approached (when traps �165 were checked); inevitably males that were estimated to be on the lek flushed with the other males on the lek. RESULTS Seventy-six leks were documented on the study area during 1986-90; 35 leks were found on the surrounding 631 ~ Fig. B-1). area in 1988 (Table B-1, Fifteen locations (10 on main study area) were also documented that were used as display sites for single males only. The density of leks was relatively stable at 0.14 leks/km2 (0.36 leks/mile2)(Table B-2). Although attendance of males at leks fluctuated between years, attendance at permanent leks (n - 19 leks with counts of displaying males all years) was positively correlated with yearly lek f - 0.006)(Fig. B-2). Attendance at all leks showed a similar relationship (~ - 0.787, f - 0.072). density (~ - 0.960, Yearly changes in attendance of males at leks throughout the study were examined for consecutive years (Fig. B-3). that fluctuations independent; These results indicated in attendance of males at neighboring leks may not be for example, attendance of males at leks generally increased on the western side of the study area in 1988 and decreased 1989. in However, when yearly changes in attendance of males (number) were compared between each lek and the nearest neighboring lek, the yearly changes were not positively correlated for 1986-87 (~ - 0.062, f 0.663), 1987-88 (~ - -0.069, f - 0.582), 1988-89 (~ - -0.035, f 0.791), and 1989-90 (~ - -0.230, f • 0.028). relationship was not significant periods combined (Fig. B-4). Similarly, the (r • 0.028, f • 0.375) with all time �166 Table 8-1. Maximum attendance of male greater prairie-chickens at display sites in northeastern Colorado, 1986-90 (/+'.- active lek without a count of males; ,_, - activity at site not known). Univeral Transverse Male Mercators (Zone 13) Lek 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 attendance Legal description East (m) North (m) Township Range Section Quarter 707970 709090 709830 710230 710480 710650 711180 711380 711750 712900 713270 714390 714540 714880 715420 715820 715830 716370 716610 716670 717050 717100 717150 717180 717250 717730 717750 717780 717930 717890 718130 718350 718690 718860 719030 719040 Continued. 4448270 4449010 4447340 4454050 4449370 4454850 4449000 4453280 4450530 4458300 4462440 4464320 4460620 4453420 4454310 4453760 4448010 4453120 4456480 4453840 4455600 4457710 4448870 4454700 4454290 4441630 4451570 4447490 4464480 4448140 4450100 4449920 4453530 4457680 4453800 4440690 3N 2N 2N 3N 2N 3N 2N 3N 3N 3N 4N 4N 4N 3N 3N 3N 2N 3N 3N 3N 3N 3N 2N 3N 3N 2N 3N 2N 4N 2N 2N 2N 3N 3N 3N IN 46W 46W 46W 46W 46W 46W 46W 46W 46W 46W 46W 46W 46W 46W 46W 46W 46W 46W 46W 46W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 7 5 8 20 5 21 4 28 33 10 27 23 35 25 24 24 12 25 13 24 18 7 7 19 19 31 31 . 7 19 7 6 6 29 8 20 5 NW SW SE SE NE NW SW NE SE NE NE NE -SE NW SW SW NW NE NE SE SW SW NW NW SW NW NE SE NE SE NE NE NW SW SW NW 86 87 88 89 90 - - - - - + 14 3 + - - 3- - - 3 0 0 0 0 + 9 3 0 5 9 6 9 3 2 6 4 7 15 0 0 14 12 + - - 0 0 0 2 - 0 0 8 8 0 0 - 0 2 9 8 3 3 5 1 2 17 10 3 2 7 4 10 0 2 5 19 3 10 17 0 12 17 1 12 6 2 0 9 4 15 12 26 - - - - - - - - - 0 0 0 12 15 0 8 12 0 11 13 0 7 - 8 - 0 0 0 0 7 0 11 6 o 2 8 6 0 8 0 - - 0 6 14 0 6 9 0 14 11 0 10 - 6 0 10 0 9 0 - �167 Table 8-1. Continued. Male Univeral Transverse Mercators (Zone 13) attendance Legal description Lek East (m) North (m) Township Range,Section Quarter 86 87 88 89 90 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 719100 719340 719590 719630 719890 719920 720060 720470 720620 720980 721230 721250 721620 721750 721900 722100 722370 722440 722510 722850 723020 723300 723320 723440 723450 723780 724110 724120 724180 724270 724420 724450 724830 724960 725280 725750 725870 726290 726410 726520 Continued. 4443610 4451710 4464240 4453920 4464190 4449630 4448250 4456320 4455520 4458240 4455970 4450580 4445270 4461370 4455230 4453700 4463250 4453940 4456230 4456700 4456460 4458750 4463170 4450180 4455900 4444340 4453510 4454510 4463360 4459920 4449180 4455370 4448130 4447950 4450980 4447080 4445950 4447050 4449940 4455730 2N 3N 4N 3N 4N 2N 2N 3N 3N 3N 3N 2N 2N 4N 3N 3N 4N 3N 3N 3N 3N 3N 4N 2N 3N 2N 3N 3N 4N 3N 2N 3N 2N 2N 3N 2N 2N 2N 2N 3N 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 45W 44W 29 32 20 16 21 5 8 16 16 9 16 4 21 34 22 27 27 22 15 15 15 2 26 2 14 23 26 23 26 2 2 23 '11 12 36 13 13 13 1 18 NW NE NE SW NW SE NE NW SW NE SE NE NE NW . NW NW NE SE NE NE NE SW NW NW SW SW NE SE NE NE SE NE SE SW SW NW SE NE SE SW + + 19 16 11 5 0 0 - - 4 0 2 0 - - 3 14 18 24 0 2 0 0 0 8 0 2 0 6 6 16 0 0 8 0 0 8 + + 3 - - 6 18 10 12 11 14 14 6 0 5 0 0 1 0 4 5 4 4 6 6 5 0 0 2 0 0 4 0 4 1 0 0 5 2 0 0 0 0 1 1 5 6 13 10 8 10 0 0 1 12 6 14 7 8 0 7 8 8 0 o 10 2 5 0 2 0 0 0 2 1 12 9 9 - - - 4 0 - - 0 2 - - 14 0 6 0 5 2 0 10 3 3 0 2 1 0 + 9 9 10 12 9 - - 0 0 11 0 0 0 0 2 1 0 0 0 0 0 0 0 0 0 0 0 7 9 0 6 8 10 11 0 0 0 11 6 7 0 3 11 6 10 0 0 0 10 �168 Table 8-1. Continued. Male Univeral Transverse Mercators (Zone 13) attendance Legal description Lek East (m) North (m) Tow~ship Range Section Quarter 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 III 112 113 114 115 116 726700 727160 727280. 727410 727450 727590 727760 728090 728280 728300 728590 728630 728730 728740 728830 728940 729030 729820 730150 730360 730390 730430 730550 730970 731000 731320 732060 732420 732470 733080 734040 734150 734620 734700 735240 735690 725230 732740 733210 729960 Continued. 4450140 4444880 4444760 4461430 4454630 4456700 4462440 4458320 4447390 4460090 4448100 4448610 4445330 4448260 . 4464820 4448110 4457150 4466220 4458700 4449870 4446390 4450070 4464090 4455770 4447120 4445470 4462010 4445100 4454660 4446330 4459030 4451990 4459970 4453650 4448720 4456600 4455640 4445270 4444830 4452240 2N 2N 2N 4N 3N 3N 4N 3N 2N 3N 2N 2N 2N 2N 4N 2N 3N 4N 3N 2N 2N 2N 4N 3N 2N 2N 4N 2N 3N 2N 3N 3N 3N . 3N 2N 3N 3N . 2N 2N 3N 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 44W 45W 44W 44W 44W 6 19 19 31 19 18 30 8 17 5 8 8 20 8 20 8 8 16 9 4 16 4 21 16 16 . 21 34 22 22 14 2 35 1 25 12 13 13 22 23 33 NW SE SE NE SE NE SE NW NW NW SW NW NW NW NE SE SE NW NW SW SW NW SE SE NE NE NE SE SE SW SE NE NW NW NW NE SW NE SW NW 86 87 88 89 90 9 9 8 9 8 9 10 0 0 0 7 17 - 6 + 12 17 14 + + 9 4 - - 1 - - 8 4 0 0 0 1 0 0 1 0 8 7 0 0 9 10 10 8 0 o 10 9 8 0 0 1 0 5 + 2 2 3 0 0 1 2 7 18 26 12 0 0 4 0 6 - 9 8 10 14 10 0 0 4 0 6 6 4 5 0 4 4 0 0 0 2 3 + 8 - 10 3 1 0 0 0 3 0 0 0 7 0 0 o 11 0 0 0 3 - 1 0 9 - 25 4 - 0- 0- - - - - - - - - - - - 0 6 17 0 - 0 11 0 - 6 0 0 0 0 0 17 a �169 Table 8-1. Continued. Male Univeral Transverse Mercators (Zone 13) attendance Legal description Lek East (m) North (m) Township Range Section QUarter 86 87 88 89 90 117 118 119 120 121 122 123 -124 125 126 727720 716660 717290 719070 728830 716840 717280 719840 721780 716610 4452770 4452040 4451310 4445590 4453620 4451610 4450980 4452720 4457720 4458130 3N 3N 3N 2N 3N 3N 3N 3N 3N 3N 44W 46W 45W 45W 44W 45W 4SW 4SW 45W 46W 30 36 31 20 29 31 31 29 10 12 SE NE NW NW NE NW SW SE SW NE 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o 0 0 0 0 0 0 0 0 0 12 0 0 0 0 0 0 0 9 1 4 8 1 1 1 4 o 14 0 2 �.J../V N DISPLAY SITES o R47W! R4SW R45W ! R44W , I I T4N T3N I ~ ! 1 ~ I ; , : :: q 2( 100 :]::TJ;~~iC:;;,t!lo;~~~~J~it~;~ 1;:~;~J T3N ~ ~ I ; . , i :2 : I . : : 0 : ~'Q :.. : : 0.: : 52 54 ~80 i20 :0 i 111: 0: : 0: ;185 : ; ·······it~~~~~·:l24·t·······t···~t71···t····9.+·····1bS j +.., r······I·······l······I········I······i,······· I o~S1~13 !78~ ~047 07: : l' ~ . . CO : ! 9 80081 :0 ~ I ~ 75:)0: : : ~~': : :: o. o· ! i -r----r-- 0:: T2N. T1 N ! . r·······j······+······~····-+·····-+······ ·····.··i·······"'6'····82····a~··+······+···o·i······-+·······~~··i·Q.······· : I ~ ! ~~ 0 i i . 170! O~! ~ ~ S~70 i QOoJ2: i 1 10, :~::l~·:r=I:::~r:::I=;-T::t~~:r::J=T:::rtJ~Ivti;J~ 1 T2N :::r~t::::tTK¢Vi··r::l~rt··1°.1-:";._; l,otF @' , , , . :·+I+··-I-!·······H·····+·-r·l·ri@H, i· I : i I . . , : : " , i : '0' :48: : 82 : , i ~,o ,. ,02 ~ 0:011 i··' .;-_. Y fRP- - -!.•'_~-._••-'_ ••.,'_••'_••-_-•.'_.••. '•.•.•.: iii i iii R47W R4SW R45W R44W e , , T1N 2 I , 4KM I Fig. 8-1. Display sites of male greater prairie-chickens in northeastern Colorado during early - late spring (15 Feb-IS May) 198690. Numbers refer to the lek numbers on Table 1. �171 Table 8-2.· Indices of male greater prairie-chicken abundance in northeastern Colorado, 1986-88. 1986 1987 1988 1989 1990 Active 41 42 47 42 41 Persistent 41 33 28 25 24 Additional 41 9 15 6 5 33 30 34 34 Index Number of leks Still active from previous year Number of displaying mal es/l ek All leks .& 7.11 7.26 10.66 9.02 8.41 SO 3.72 4.35 6.46 3.80 4.72 .& 8.90 9.79 13.37 9.79 7.79 SO 3.64 3.93 5.05 2.40 3.19 Leks/krrf 0.14 0.14 0.15 0.14 0.14 Leks/mile2 0.35 0.36 0.40 0.36 0.35 Mal es/krrf 0.98 1.02 1.69 1.23 1.17 Ma 1es/mi 1e2 2.55 2.66 4.38 3.20 3.03 Permanent leks Lek density Displaying male density- ~ales displaying alone were used in the analysis. �172 16,-------------------------------~ 1988 6 ~--------~--------~--------~------~ 40 42 44 46 48 NUMBER OF LEKS Fig. 8-2. Relationship between maximum attendance of male greater prairie-chickens at 19 permanent leks (active every year with complete information) and total number of leks on the study area in northeastern Colorado, 1986-90 (vertical lines are 95% confidence intervals). �173 Fig. 8-3. 1986-87 1987-88 1988-89 1989-90 Change in male attendance at 86 display sites between years on a study area in northeastern Colorado, 1986-90. Lines represent contours of equal change in attendance of males at leks. Darkened shading indicates areas with an increase and lighter shading indicates areas with a decrease in lek attendance. �1./4 ~ * W ...J , , ~ W 20 - • •• ._._. ::: __ • 1. __ - : .•__ .• .•.• _~ .•.•.• , c::: L5 * * z 1() -~ * ~ ..••.... ~ .. ~~ , r-, o z o -- ~ ~ -10 W ~ , : 2 * *4 :*3** * t : 2* * ~* :* : 2 *: * : : * 2*:32 * : 2433: 2*'" ,* : * ** * ~4 *3* *.* :** ***5*2~62 4* ** • ·············-······f·········~-·~-·~~·~~~··~-···~···~* • 2442643*** * :* * 2 * * *3'**22 **4 : ** 24+4 3 : * * 2 * *3:* 3* : * *** *"1'* 2* 'I' *2*:** *: . 2: *2 2*: 2 2: , '" ' ••••••••••••••••••••••••••••••• _••••••• J••••••••••••••••••• _L._ ~ __ ., : . * '" Z « J: I . T (!') o :: .. " ... w C§ z w ** * -1() ~ . ~ . I . ,, , ** I I I o 1() 2() CHANGE IN ATTENDANCE AT EACH LEK Fig. 8-4. Comparison of yearly changes in attendance of males (number) at each lek and its nearest neighboring lek for the study area in northeastern Colorado, 1986-90. �175 Twenty percent (8 of 41) of leks active in 1986 were inactive in 1987, 29% (12 of 42) of leks active in 1987 were inactive in 1988, 28% (13 of 47) of leks active in 1988 were inactive in 1989, and 19% (8 of 42) of leks active in 1989 were inactive in 1990 (Fig. 8-5). lek disappearance rate was 23.8%. The annual Twenty-four leks were active all 5 years, 3 for 4 years, 10 for 3 years, 12 for 2 years, and 27 for 1 year (Fig. 8-6). Over the limited duration of this study, the number of permanent leks (active every year) appeared to approach an asymptote of over 20 leks. Likewise, the number of additional leks (leks not previously described) appeared to be approaching an asymptote indicating a finite number of possible lek locations on the study area. Male greater prairie-chickens ~ere on leks an average of 94.5% of the time they were located during normal periods of lek activity (n - 13 males with an average of >20.observations/bird periods)(Fig. B-7). during normal display Values ranged from 86.7% to 100.0%. Although 5 males captured during winter (X - 96.8%, n - 5) tended to have slightly higher lek attendance rates than males captured on leks (X - 93.1%, n = 8), differences in rates of lek attendance by individual males were not detected (~ - 10.647; f - 0.559). When lek attendance for radio-marked males was examined independent of individual differences, the attendance rate was 95.1% for 286 observations of 21 males. Males captured during winter (96.9%) tended to have slightly higher (~ - 2.719, f - 0.099) lek attendance rates than males captured on leks (92.7%). Although, there were no apparent differences associated with age (1 = 0.910, f • 0.382), yearlings apparently visited more leks during the breeding season than adults. Three of 4 yearling males visited> 1 �176 II4IW 14N N ---.---.-.~. ~:--.. --~: SIZE OF LEKS .9 TaN 2-5 MALES o 6-10 MALES o 11-15 MALES o >15 MALES o 2 II4IW I UN ~.~.~:~ TaN TIN 41<M , II•• W T4N T4N 9 UN TaN TIN 9 1987 WllAY 1988 WllAY T4N T4N ----------r.-""-'!"""""-""",,, ~ TIN .TIN 1989 II4IW Fig. 8-5. II•• W II4IW II•• W Distribution of greater prairie-chicken leks on the study area in northeastern Colorado~ 1986-90. �177 -•••o g;!1 ..• <2 -- ...... - en TEMPORARY L5 >3 .. .•. a: ,, LL .•. 1986 - ... - --- --- 1987 -< . ,, 1988 ~ :::c 0 ffi4 r::c PERSISTENT 1989 :E ::> Z5 1990 o 10 20 30 40 NUMBER OF LEKS Fig. 8-6. Stability of leks (histogram) and number of persistent (active all previous years of study) and additional leks (not previously described) on the study area in northeastern Colorado during 1986-90. �.lHS 4 rum CAPTURED ON LEKS [J CAPTURED IN WINTER C1J3 W ...J -c ::is LL °2 a: W to ::is ::> Z1 o >86-88 >88-90 >90-92 >92-94 >94-96 >96-98 >98-100 LEK ATTENDANCE (%) Fig. 8-7. Frequency of lek attendance by 8 male greater prairie- chickens captured on leks and 5 males captured at winter feeding sites in northeastern Colorado during 1986-90. �179 lek while only 1 of 17 adults visited> 1 lek ()( - 10.032, f - 0.002). In addition, 1 yearling was observed on 4 leks while another was observed on 6 leks. same morning. The latter male also was observed on 2 leks on the In only 1 case was a radio-marked yearling male not observed on a lek during the normal morning display period. DISCUSSION Examinations of lek stability indicate the possibility that a finite number of permanent leks may exist on the study area. there may be a fin ite number of potent iall ek 1ocat ions. information desirable is useful for numerous reasons. Likewise, Th is Permanent leks may be more for territory acquisition than temporary leks. Lewis and Zwickel (1980, 1981i, h) determined that yearling male blue grouse (Dend~agapus obscurus) spend more time near permanent territories. Whether selection of leks is due to the status of dominant males (Beehler and Foster 1988), accessibility to females (Lewis and Zwickel 1981a, Bradbury and Gibson 1983), or habitat quality (Wrangham 1980) has not been adequately examined. territory desirability, In addition to problems associated with permanent leks may be more consistent with respect to male attendance than temporary leks. Differences in attendance may be important if permanent leks are easier to find than temporary leks. This latter consideration could affect estimates of both lek density and male attendance. Yearling males appeared to have visited more leks than adults. addition to the unusual pattern of lek visitation by yearling males, yearlings also visited many temporary leks. specific evidence of age composition Although there was no at temporary leks, it was possible In �they were generally composed of males unable to obtain territories on permanent leks (Cannon and Knopf 1981). more likely to be yearlings. Presumably these birds were Although multiple lek visitations were observed in other populations, ages of males were rarely known ·(Hamerstrom and Hamerstrom 1949, Arthaud 1968, Silvy 1968, Robel et ale 1970, Robel and Ballard 1974). Rippin and Boag (1974) found that removals of territorial male sharp-tailed grouse from leks resulted in an influx of new males; they suggested that these newly established males were more likely yearlings that had previcrusly been non-territorial lek. Whether these males visited> in areas associated with the 1 lek during the breeding season or occupied territories on temporary leks was not known. Although numbers of males on leks may increase at the same time numbers of leks are increasing, no spatial correlation in yearly changes in male attendance at 1eks was found. The 1ack of a corre 1at ion may be . caused by interactions among possible factors associated with lek dynamics including: 1) formation of smaller temporary leks near larger permanent leks, 2) relative consistency in numbers of males at permanent versus temporary leks, 3) survival, mortality~ and/or movement of 'hotshot' males (Beehler and Foster 1988), 4) regional fluctuations in abundance of males, 5) compensatory changes in abundance of males at neighboring leks (if 1 lek increases, an adjacent lek may decline), and/or 6) maintenance of genetic heterozygosity. Lek visitation have showed similar variability. visitation of greater prairie-chickens and 50% (Robel 1970). Estimates of lek ranged between 95% (this study) Most variation in lek attendance my be due to time of year (Bradbury et al. 1989). Visitation rates of sage grouse �181 were> 90% during the period of peak male attendance at leks and between 67% (yearlings) and 100% (adults) during the peak of hen attendance (Emmons and S'raun 1984). These results for male lek attendance pertain to serious issues concerning the census of greater prairie-chickens grouse. and other prairie Robel's (1970) paper has been cited as evidence that the actual number of males may be twice as high as the number counted on leks. However, the data in this study indicated that most males (about 95%), may be attending leks every day. This discrepancy indicates that population size would be over-estimated when lek counts and visitation rates of 50% are used. Robel (1970) estimated a value for lek attendance by male greater prairie-chickens of 50% by dividing 33 late-April territory-holders into 60 males thought to be on the area during early March (actually 55%). There are several problems which may account for the differences between Robel's estimate and the lek attendance rate observed in this study. First, sUbstantial mortality could have occurred among the estimated 27 males (60 minus 33) that disappeared between early March and late April. Second, many males that disappeared may have dispersed from the study area, which was limited to 3 leks. Likewise, the presence and status of leks around the periphery of the study area was not documented making it difficult to quantify the status of the males that disappeared. Finally, radio telemetry would have made it possible to determine whether males had dispersed. from the study area, were on or off leks, or were dead. In addition to lek visitation, methods of surveying lek attendance of prairie grouse should be evaluated. Accurate counts of males may be �· .LO,," easier to obtain when birds are flushed than when they are observed from a distance. Some males may be off the edges of leks, and hence, difficult to observe. The methodology for estimating numbers of males could be of critical importance if rates of lek visitation are used to estimate population size. LITERATURE CITED Ammann, G. A. 1944. Determining age of pinnated and sharp-tailed grouses. J. Wildl. Manage. 8:170-171. Amstrup, S. C. 1980. 44:214-217. A radio-collar for game birds. J. Wildl. Manage. Arthaud, F. L.· 1968. Populations of the prairie chicken related to land use in southwestern Missouri. M.A. TheSiS, Univ. Missouri, Columbia. 134pp. Beehler, B. M., and M. S. Foster. 1988. Hotshots, hotspots, and female preference in the .organization of lek mating systems. Am. Nat. 131:203-219. Bradbury, J. W., and R. M. Gibson. 1983. Leks and mate choice. Pages 109-138 in P. Bateson, ed. Mate choice. Cambridge Univ. Press, Cambridge, U.K. ___ , S. L. Vehrencamp, and R. M. Gibson. 1989. Dispersion of displaying male sage grouse. I. Patterns of temporal variation. Behav. Ecol. Sociobiol. 24:1-14. Cannon, R. W., and F. L. Knopf. 1981. Lek numbers as a trend index to prairie grouse populations. J. Wildl. Manage. 45:776-778. Emmons, S. R., and C. E. Braun. 1984. Lek attendance of male sage grousew J. Wildl. Manage. 48:1023-1028. Hamerstrom, F. N., and F. Hamerstrom. 1949. Daily and seasonal movements of Wisconsin prairie chickens. Auk 66:313-337. ___ , and . 1973. The prairie chicken in Wisconsin. Nat. Resour. Tech. Bull. 64. 52pp. Wis. Dep. Lewis, R. A., and F. C. Zwickel. 1980. Removal and replacement of male blue grouse on persistent and transient territorial sites. Can. J. Zool. 58:1417-1423. , and . 1981A. Differential use of territorial sites by ---male blue grouse. Condor 83:171-176. �183 ___ , and _~_. 1981.12. Survival and delayed breeding in male blue grouse. Can. J. Zool. 60:1881-1884. Miller, G. C. 1984. Development of a preservation program for insular populations of prairie grouse. Colorado Div. Wildl. Fed. Aid Rep. N-I-R. Jan. Pages 129-170. Rippin, A. B., and D. A. Boag. 1974. Recruitment to populations of male sharp-tailed grouse. J. Wildl. Manage. 38:616-621. Robel, R. J. 1970. Possible role of behavior in regulating greater prair)e chicken populations. J. Wildl. Manage. 34:306-312. ___ .'J. N. Briggs, J. J. Cebula, N. J. Silvy, C. E. Viers, and P. G. Watt. 1970. Greater prairie chicken ranges, movements, and habitat usage in Kansas. J. Wildl. Manage. 34:286-306. ___ , and W. B. Ballard, Jr. 1974. lek social organization and reproductive success in the greater prairie chicken. Amer. Zool. 14:121-128. Silvy, N. J. 1968. Movements, monthly ranges, reproductive behavior, and mortality of radio-tagged greater prairie chickens (Tympanuchus cupido pinnatus). M.Sc. Thesis, Kansas State. Univ., Manhattan. 135pp. Wrangham, R. W. 1980. Female choice of least costly males; a possible factor in the evolution of leks. Z. Tierpsychol. 54:357-367. Prepared by _'l1LJJ~~':"=;..Jo..._~~_":_'..::;:~::;;;';;,_:;_--=:.._;_=-__ Michael A. Schroeder Graduate Research Assistant Approved by _..;;;;..a.....;;~;..;..;....__. _Z_. ....I.~-=--.;;____;;;_ Clait E. Braun Wildlife Research Leader _ �\j �185 JOB PROGRESS REPORT Colorado State of: Project: W-ls2-R Upland Bird Research Work Plan: 17 Job Title: Population Dynamics of White-tailed Ptarmigan Period Covered: Author: Job 7 _ 01 January through 31 December 1990 Clait E Braun and Kenneth M. Giesen Personnel: Kathy Martin, University of Toronto; Clait E. Braun and Kenneth M. Giesen, Colorado Division of Wildlife ABSTRACT Long-term studies of populations of white-tailed ptarmigan (Lagopus leucurus) were continued at hunted (Mt. Evans) and_unhunted (Rocky Mountain National Park) areas in Colorado through 1990. Densities .of breeding ptarmigan increased at Rocky Mountain National Park and were stable at.Mt. Evans. Nest success at Mt. Eyans was average (50%) and was below avera~e (40%) at Rocky Mountain National Park. At least 7% of the ptarmigan banded in 1990 at Mt. Evans were harvested during the 1990 hunting season. Nonreporting of bands may be an important problem. ��187 POPULATION DYNAMICS OF WHITE-TAILED PTARMIGAN C1ait E. Braun and Kenneth M. Giesen Long-term studies of trends in population size and investigation of reasons for fluctuations in size of tetraonid populations are lacking. Studies on the population dynamics of unhunted and hunted populations of white-tailed ptarmigan were initiated in Colorado in 1966 and have continued essentially uninterrupted at 2 sites. Studies of the unhunted population (Rocky Mountain National Park) identified possible short-term cycles of 7-8 years with an amplitude of 25-30% between high and low breeding densities. Conversely, studies of the manipulated population (hunted) at Mt. Evans have not indicated any cyclic pattern and it would appear that controlled hunting may mask any long-term trend that may occur. This study is designed to examine the question whether white-tailed ptarmigan are truly cyclic and whether hunting affects the apparent oscillations. P. N. OBJECTIVES The goals of this investigation are to be able to predict the length and amplitude of cycles in white-tailed ptarmigan in Colorado, to examine the impact of hunting on cycles, and to clarify underlying causes of the apparent cycles. SEGMENT OBJECTIVES 1. Conduct breeding (May-Jun) and brood (Aug-Sep) censuses of white~tailed ptarmigan using tape-recorded calls of males (breeding) and chicks (broods). 2. Censuses will be conducted on previously established, defined study areas at Mt. Evans (hunted) and at Rocky Mountain National Park (unhunted). 3. Capture (noose poles) and band (aluminum and plastic color-coded bands) all unmarked white-tailed ptarmigan encountered on study areas at Mt. Evans and at Rocky Mountain National Park. 4. Individually identify all ptarmigan observed on study areas at Mt. Evans and Rocky Mountain National Park through use of binoculars. 5. Make hunting season and bag limit recommendations for Mt. Evans and collect hunting data through use of volunteer wing barrels and hunter field checks. 6. Compile data, analyze results, and prepare progress reports. �188 STUDY AREA AND METHODS Areas investigated were Mt. Goliath-Mt. Evans in Clear Creek County and at Tombstone Ridge-Sundance Mountain to Fall River Pass in Rocky Mountain National Park in Larimer County. The physiography, geology, location, and vegetation of these study areas have been previously described (Braun 1969, 1971; Braun and Rogers 1971; Giesen 1977). Ptarmigan were located through use of tape-recorded calls (Braun et al. 1973), captured through use of telescoping noose poles (Zwickel and Bendell 1967) as described by Braun and Rogers (1971), and classified to age and sex and banded following Braun and Rogers (1971). Age of chicks was estimated following Giesen and Braun (1979). Numbered plastic bandettes were not used as in earlier years (Braun and Rogers 1971) as a color-code system using up to 4 different colored plastic bandettes was instituted in 1977-78. A check station was operated on the Mt. Evans highway during the opening weekend of the ptarmigan season in that area. A volunteer wing collection station WaS available to hunters in the area when the check station was not in operation until the season closed. RESULTS AND DISCUSSION Breeding Densities Mt. Evans.--Timing of breeding events in the Mt. Evans area was about the same in 1990 as in 1989. During the May-early June interval, 16 pairs were identified. Thus, breeding densities remained essentially unchanged from 1989 (Table 1). During the breeding season, 2 of 16 males identified were yearlings while 5 of 16 hens were yearlings. Recruitment of yearlings was lower than in 1989. Rocky Mountain National Park.--Timing of breeding events on the Trail Ridge study area was similar to the long term average and about 1 week later than in 1989. Surveys of ptarmigan on breeding territories along Trail Ridge Road in May and June indicated a minimum population of 75 birds and included 31 pairs and 13 unpaired males. This represents a 10% increase over 1989 and is the highest population since 1981. However, this population level is less than 70% of the breeding densities recorded during peak years in 1969 and 1976. The increased breeding density reflected above average survival of banded adult males (37 of 60, 61.7%) and females (17 of 35, 48.6%) from 1989. Survival of banded chicks was 20% (2 of 10) but yearlings comprised 26% of all adult ptarmigan identified in·1990. Mt. Evans.--Thirty hens were located during mid July-early September 1990 on or immediately adjacent to the study area. Fifteen hens (50.0%) were with broods while 15 were apparently unsuccessful nesters (without chicks). Average brood size to 1 September was poor (2.1 chicksjhen). Hatch dates varied from early to late July. Rocky Mountain National Park.--Nest success was estimated from the proportion of hens with broods and broodless hens observed in July and August. Seven of 18 hens observed during summer surveys were with broods for an estimated nest success rate of 40%. However, 4 hens (radio-marked) observed without chicks were known to have hatched clutches but lost all chicks soon after hatch. The �189 peak of hatch occurred during the 2nd and 3rd weeks of July. size in August was 4.2 chicksjhen. Table 1. 1966-90. Average brood White-tailed ptarmigan breeding densities (birdsjkm2), Colorado Study area Year 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 .1982 1983 1984 1985 1986 1987 1988 1989 1990 Rocky Mountain National Park (5.5 km2) Mt. Evans (4.0 km2) 11.3 9.8 11.5 12.0 9.6 9.1 8.7 7.8 8.0 11.1 13.5 12.9 10.7 8.7 8.4 8.2 7.8 6.7 5.8 6.0 4.5 6.0 5.4 6.2 7.6 3.0 2.7 2.7 2.2 2.0 4.2 7.5 6.2 6.2 6.2 6.7 > 6.0 7.5 10.3 9.5 9.0 6.5 6.5 8.0 8.0 6.5 5.0 7.5 8.0 8.0 Harvest Mt. Evans.--The hunting season at Mt. Evans in 1990 opened on 15 September and closed on 7 October (23 days) with a bag and possession limit of 3 and 6. Thus, the season was delayed 1 week from the statewide opening as it was in 1981 and 1986-89. The season opening was delayed 2 weeks from 1978 to 1980 and 1982 to 1985. Prior to 1978, experimental seasons were in effect (19701976) or the season opened with the statewide grouse seasons (dates from 17 Aug to 14 Sep). Unlike 1987 and 1988 when the Mt. Evans road was closed due to reconstruction (Lincoln Lake area in 1987, above Ptarmigan Flats in 1988), the Mt. Evans road was open tb Summit Lake from 15 to 28 September when it �190 closed because of snow. Twenty hunters were checked on 15-16 September. These hunters observed 50 ptarmigan and harvested 13 of which 12 were banded. Seven additional wings (no bands) were received on 21 and 23 September in the wing barrel. Thus, a minimum of 20 ptarmigan were harvested at Mt. Evans of which at least 12 were banded. Five of the banded birds harvested were banded in 1990 (5/69 - 7.2%) of which 4 were chicks (4/24 - 16.7%). The other banded birds harvested were banded in 1986 (1), 1987 (1), 1988 (1), and 1989 (4). LITERATURE CITED Braun, C. E. 1969. Population dynamics, habitat, and movements of whitetailed ptarmigan in Colorado. Ph.D. Thesis, Colorado State Univ., Fort Collins. l89pp. 1971. Habitat requirements of Colorado white-tailed ptarmigan. West. Assoc. State Game and Fish Comm. 51:284-292. Proc. _____ , and G. E. Rogers. 1971. The white-tailed ptarmigan in Colorado. Colorado Div. Game, Fish and Parks Tech. Publ. 27. 80pp. _______ , R. K. Schmidt, Jr., and G. E. Rogers. 1973. Census of Colorado whitetailed ptarmigan with tape recorded calls. J. Wild1. Manage. 37:90-93. Giesen, K. M. 1977. Mortality and dispersal of juvenile white-tailed ptarmigan. M.S. Thesis, Colorado State Univ., Fort Collins. 5Spp. _______ , and C. E. Braun. 1979. A technique for age determination of juvenile white-tailed ptarmigan. J. Wild1. Manage. 43:508-511. Zwickel, F. C., and J. F. Bendell. J. Wildl. Manage. 31:202-204. Prepared by Clait E.'Braun Wildlife Research Leader Kenneth M. Giesen Wildlife Researcher C 1967. A snare for capturing blue grouse. �JOB PROGRESS REPORT Colorado State of: Project: W-152-R Upland Bird Research Work Plan: 21 Job Title: Sandsage-B1uestem Period Covered: Author: Job _3_ 01 January Prairie Renovation through 31 December 1990 Warren D. Snyder Personnel: C. Braun, L. Crooks, T. Davis, T. Remington, M. Schroeder, Wilson, and W. Snyder, Colorado Division of Wildlife D. ABSTRACT Except for June, which was hot and dry, precipitation in 1990 was above average and conducive to growth of rangeland vegetation. Below average precipitation in 1989, however, was reflected in lower height-density indices (HDI) of residual grass-forb vegetation in early spring 1990. The data confirm that impacts of fire on grass-forb vegetation (either positive or negative) were relatively short-term. Effects of treatments conducted from 1984 through 1986 were not sustained intq 1990. Sand sagebrush (Artemisia filifo1ia) ~ecovered more slowly from fire and differences between treatments and controls were still noted in 1990. Prairie sandreed (Calamovilfa longifolia), especially, and other warm-season grasses, to some extent, were suppressed by hot, dry weather in June, 1990. There was no evidence that sand dropseed (Sporobolus cryptandrus) was impacted by fire. Limited data indicated that sand b1uestem (Andropogon halli) was enhanced by fire and consistently increased under the ungrazed management of the Tamarack Prairie. Neither perennial forbs nor annual forbs showed evidence of being impacted by fire. The height-density of switchgrass (Panicum virgatum) dominated strips, revegetated in 1985, declined slightly in 1990 due to decreased precipitation in 1989. However, the me,an HD;r of 3.6 dm was much greater than that of other vegetation within the TairiarackPrairie. Within the t~l1age-herbicide renovation tract, treated in 1986, sustained enhancement of switchgrass': b1uestem vegetation continued. Standing residual of sand sagebrush, killed by herbicide in 1985 within an east Tamarack Prairie site, deteriorated markedly from the previous year. Monitoring of greater prairie-chickens (Tympanuchus cupido) revealed deterioration of 2 established leks'on private lands near the southern edge of the Tamarack Prairie; establishment of a small lek at a mowed site on the property; and discovery of a new 1ek about 4.5 kID south of the Tamarack Prairie. Increased numbers of sharp-tailed grouse (I. phasianellus) were evident in spring 1990 and several hybrid crosses of the 2 species were observed at the new lek. Management personnel trapped 23 greater prairie chickens in Yuma County in April 1990 and released them on the east part of the Tamarack Prairie. Among 4 radio-marked hens that were released, 2 nested �and reared young on the property. Two of 4 radio-marked transplanted males survived and became active respectively at leks land 2. One-third of the 12 radio-marked hens (resident and transplanted) were lost to predation, however, 7 of 8 surviving hens nested successfully. This sample included 1 female sharp-tailed grouse. Brood survival through summer was not accurately assessed. �193 SANDSAGE-BLUESTEM PRAIRIE RENOVATION Warren D. Snyder P. N. OBJECTIVES Test renovation and revegetation techniques for increasing standing residual height-density of grasses, the proportion of tall warm-season grasses within the composition, and for reducing the quantity of sand sagebrush to <30% canopy cover in an ungrazed sandsage-bluestem prairie on the South Tamarack, South Platte Wildlife Area in northeastern Colorado. SEGMENT OBJECTIVES Monitoring follows: of environmental and vegetation conditions and changes continued as 1. Precipitation was monitored throughout the year supplementing data from 4 electronic rain gauges with information from nearby weather stations through the winter months. 2. Soil moisture accumulations, plant phenology, and weather were monitored primarily in spring and especially at the time of controlled burns. 3. Visual obstruction (height-density) measurements were obtained on treatments and controls where applicable in late winter and/or early spring prior to green-up. 4. Crown cover, species composition, and frequency of occurrence measurements were obtained from mid-summer to early fall. 5. Male and female greater prairie-chickens were trapped on leks adjacent to the Tamarack Prairie in April 1990 and equipped with battery-powered (7 g) transmitters. Their survival, movements, use of habitat types for nesting, feeding and loafing, and use of the Tamarack Prairie was monitored through spring, summer, and fall. 6. Data compilation and writing the annual job progress conducted during winter 1990-91. report were METHODS Approaches used were described by Snyder (1986~, 1986Q, 1987, 1988,' 1990) and are outlined in the Segment Objectives. Segment Objective #4 was conducted within the 1985 and 1986 burn sites and their controls after not being conducted in 1989, and was deleted within the 1984 burns. Walk-in traps were placed on leks near the Tamarack Prairie in early April 1990 to trap greater prairie-chickens, plains sharp-tailed grouse, and hybrids of the 2 species. Trapped birds were marked with numbered aluminum leg bands �and color-marked with plastic bandettes. Poncho-mounted, battery-powered transmitters were placed on 3 males (2 were sharp-tailed grouse) and 8 females (1 sharp-tailed grouse) resident in the area. Transmitters were also placed on 4 males -and 4 females among 23 greater prairie-chickens released on the Tamarack Prairie in April 1990. Additional males trapped on the leks were banded and released. RESULTS AND DISCUSSION Environmental Conditions Precipitation during the first few months of 1990 was slightly above average (Fig. 1) which increased soil moisture in comparison to spring 1989. Soil probe indices in early and late April and on 24 May remained nearly constant (Table 1) averaging 9.04 dm. This was almost twice the depth (4.67 dm) of probes recorded in 1989. • .JAN-MAR illIIll em X API=! MAY - 84 JUN 85 JUL U1 86 0: « W >- • AUG 87 SEP 88 • OCT-DEC 89 gO a 2 4 6 8 10 12 PRECIPITATION 14 16 18 20 22 (INCHES) Fig. 1. Monthly and annual precipitation (in.) from 1984 through 1990 in relation to the long-term mean, Tamarack Prairie, Colorado. �195· Table 1. Soil moisture accumulations (dm)a based on soil probe samples during spring 1990, Tamarack Prairie, Colorado. AJ2r Location West North-central South-central East ~ 24 30 2 8.95 10.35 12.13 7.62 8.51 8.95 12.32 6.82 aMean depth (dm) of 4 probes/location precipitation gauges. 8.06 8.32 10.22 6.22 taken near each of the 4 Precipitation during the first 3 months of 1990 was above average whereas it was below average in April, near average in May, and markedly below average in June (Fig. 1). Mean-temperatures in April and May remained below average, but June was exceptionally hot, especially during the last 2 weeks of the month (Fig. 2). Temperatures moderated in July, which was one of the wettest months recorded during the study. Precipitation continued to remain slightly above average through the late summer, fall, and early winter. Total precipitation in 1990 was above average and comparable to that received in 1987. Phenological conditions during April and May 1990 were monitored as in previous years (Table 2). Vegetation growth and development appeared similar to that recorded in 1989 although temperatures averaged slightly cooler (Fig. 2). A hard freez~ on 1 May 1989 accompanied by dry soils possibly retarded vegetation development that spring in contrast to 1990. ~ e4 85 0: -<: 111111111 A~~ [::::::::::::::1 MAY t::~:;:::;:::;:::;:::;::1 ..JUN 8S L.1..J >- 87 ee 89 90 30 35 40 45 SO 55 60 TEMPERATUI=lE 65 70 75 eo C F) Fig. 2. Monthly average temperature (F) from March through June, 1984-90 in relation to the long-term mean, as an index to vegetation phenology, Sterling, Colorado. �Table 2. Phenological conditions of selected vegetation during spring 1990, Tamarack Prairie, Colorado. Species Alliun textile Artemisia filifolia A. ludoviciana Astragalus sp. Cymopteris mont anus Erigeron bellidiastrun Lath:z:ruspolymorphus Leucocrinun montanun Mentzelia nuda Penstemon angustifolius Phlox andicola PSOralea lanceolata Sphaeralcea coccinea Tradescantia occidentalis Tragopogan sp. Agrop:z:ronsmithii Bouteloua gracilis Calamovilfa longifolia Panicun virgatun Paspalum stramineum Sporobolus cr:z:ptandrus Stipa ~ C:z:perussp. avegetation height (em). E = early, M = medium, L A r 19 2 5a budded E bloom F bloom emerging 5 emerging 5-7.6 leafing 5 late, F E bloom bloom leafed bloom 2.5 7.6-10 5 E bloom 15-18 emerging 10-13 bloom = full, 8 F blooni 5-7 leaf 5 P 2.5 15-18 = 21 4 L bloom 5-7.6 bloom L seedhead F bloom L bloom L bloom 5-10 7.6 20-30 F bloom 15-18 5 10-15 10 L bloom 5-7.6 E bloom 30-38 F bloom 20-25 5-7.6 15-20 15 P bloom 10-15 F bloom bloom 5 20-25 15 E head E bloom F bloom 5-7.6 7.6-10 emerging 5-7.6 2.5 = budded 2.5 leaf leafing 5 5-7.6 Jun Ma:z: 27 F bloom 12.7 25-30 7.6-10 15 headed past. Height-Density Sampling Within Burned Sites Below average precipitation in 1989 was the apparent reason that heightdensity indices (HDI) of residual grass-forb vegetation, in early spring 1990, were below those of the previous year. Within burns 1-84 and 3-84, treatment and control HDI transects have shown similar trends from 1987 through 1990 (Figs. 3 and 4, Tables 3 and 4) indicating there was no enhancement of vegetation growth after the initial (1984-86) suppression by fire. The HDI of grass-forb vegetation within the 3-84 burn remained suppressed based on pretreatment H~I levels (Fig. 4). Two possible explanations exist. Initial HDI samples may have been erroneous as sample size was small within the 3-84 burn. It is also possible that fire within burn 3-84, which was hotter than fire in burn 1-84, may have damaged vegetation to the extent that it was not able to completely recover. Sand sagebrush within the 1-84 and 3-84 burns recovered more slowly than grasses. Height-density indices were fully recovered by 1990 within burn 1-84 (Fig. 5), but within burn 3-84, treatment indices remained below those in controls (Fig. 6). Possibly, sage was more severely impacted by fire in burn 3-84. Grass-forb vegetation, based on HDI, recovered by the season after treatment within the 3 1985 burns (Table More rapid recovery was noted within the 3 1986 burns Their regrowth, in contrast to slower recovery within end of the 2nd growing 5, Fig. 7). (Table 6, Fig. 8). the 1984 burns, was �197 0.7 0.6 1\ E U u O.S >I(f) 0.4 CONTROL Z W 0 I 0.3 lI 19 0.2 W I 0.1 BURN a ~----~--~--------~--~----._ 84 85 86 87 88 89 90 YEAR Fig. 3. Height-density (dm) of residual grass-forb vegetation from 1984 (pretreatment) to 1985-90.(post-treatment) within the 1-84 burn and control sites, Tamarack Prairie, Colorado. / / \ \ \ > 85 86 87 88 89 90 YEAP Fig. 4. Height-density (dm) of residual grass-forb vegetation from 1984 (pretreatment) to 1985-90 (post-treatment) within the 3-84 burn and control sites, Tamarack Prairie, Colorado. �Table 3. Mean height-density (dm) within burn 1-84 and controls during spring 1984-90, Tamarack Prairie, Colorado. Years Grass/fb Burn Sandsage Combined 1984a .1985 1986 1987 1988 1989 1990 0.256 0.134 0.232 0.208 0.589 0.527 0.434 0.856 0.313 0.358 0.526 0.836 0.753 1.011 0.372 0.162 0.256 0.258 0.627 0.577 0.540 E 1984-90 1989-90 0.253 0.295 0.301 0.224 0.587 0.571 0.430 0.814 0.687 0.643 0.847 1.045 1.052 0.893 Combined 0.334 0.355 0.368 0.309 0.622 0.628 0.475 Values 1.12 0.54 0.01 0.65 Control Grass/fb Sandsage 0.79 3.25 apretreatment samples. Table 4. Mean height-density (dm) within Burn 3-84 and controls during spring 1984-90, Tamarack Prairie, Colorado. Years Grass/fb Burn Sandsage 1984a 1985 1986 1987 1988 1989 1990 0.222 0.021 0.106 0.077 0.466 0.647 0.378 0.827 0.121 0.356 0.286 1.215 1.435 1.068 E 1984-90 1989-90 2.54 0.04 apretreatment. Combined " 0.493 0.047 0.201 0.157 0.831 1.159 0.680 Values 0.88 0.58 2.26 0.86 Grass/fb Control Sands age Combined 0.183 0.191 0.200 0.216 0.625 0.934 0.446 0.935 0.797 1.044 0.688 1.494 1.888 1.579 0.531 0.503 0.629 0.424 1.059 1.548 0.984 �199 1.1 1.0 1\ E 0.9 U CONTROL U >- 0.8 I/) 0.7 " ,,l· ,, l•... )(,- Z W 0 , , , , , , -_.J,/" 0.6 I lI 0.5 W o.~ 19 I 8URN 0.3 0.2 84 8S 86 87 88 89 90 YEAR Fig. 5. Height-density (drn) of sand sagebrush from 1984 (pretreatment) to 1985-90 (post-treatment) within the 1-84 burn and control sites, Tamarack Prairie; Colorado. 2.0 1. B 'E' -0 '--.J >- I- 1.6 1.4 1.2 U1 :z: L.l.J 1.0 Cl I I- :c t.:J L.l.J :c 0.8 0.6 0.4 0.:2 0 S""I 8:5 86 87 88 89 90 YEAR Fig. 6. Height-density (drn) of sand sagebrush from 1984 (pretreatment) to 1985-90 (post-treatment) within the 3-84 burn and control sites, Tamarack Prairie, Colorado. �200 Table 5. Colorado. Mean height-density (dm) within 1985 burns and controls during spring 1985-90, Tamarack Prairie, ControL Burn Year 2 3 2 3 ! 0.374 0.325 0.322 0.511 0.774 0.423 0.346 0.280 0.376 0.775 1.220 0.667 0.158 0.180 0.156 0.443 0.771 0.316 0.323 0.277 0.325 0.644 1.025 0.529 0.8n 0.828 0.925 1.070 1.242 1.443 0.615 0.745 0.560 1.732 1.873 1.730 0.537 0.767 0.648 1.253 1.844 1.267 0.627 0.771 0.670 1.317 1.765 1.414 0.444 0.391 0.383 0.581 0.844 0.535 0.369 0.335 0.393 0.859 1.332 0.750 0.323 0.465 0.411 0.878 1.609 0.661 0.380 0.382 0.394 0.782 1.254 0.666 ! GRASS-FORB 1985a 1986 1987 1988 1989 1990 0.507 0.138 0.419 0.780 1.081 0.542 0.381 0.119 0.4n 1.028 1.297 0.552 0.180 0.053 0.244 0.667 0.850 0.315 0.379 0.110 0.408 0.877 1.142 0.495 SANDSAGE 1985a 1.008 0.417 0.523 0.938 1.313 0.688 1986 1987 1988 1989 1990 0.679 0.342 0.591 1.167 1.582 1.050 0.642 0.438 0.769 1.144 1.385 0.955 0.744 0.388 0.6n 1.125 1.446 0.914 COMBINED 1985a 1986 1987 1988 1989 1990 0.565 0.142 0.425 0.786 1.109 0.548 0.407 0.130 0.476 1.037 1.340 0.567 0.302 0.088 0.330 0.766 1.017 0.359 F VALUE 1989-90 1985-90 Grass-forb Conbined apretreatment. 2.56 10.95 1.36 8.75 0.429 0.124 0.426 0.899 1.196 0.513 �201 Table 6. Colorado. Mean height-density (dm) within 1986 burns and controls during spring 1985-90, Tamarack Prairie, Burn Year 2 Control 3 ! 2 3 ! GRASS-FORB 1985a 0.326 0.314 0.259 0.292 0.294 0.316 0.233 0.275 1986a 1987 1988 1989 1990 0.304 0.120 0.543 0.n3 0.386 0.337 0.437 1.359 1.159 0.666 0.256 0.202 0.824 1.019 0.361 0.290 0.226 0.855 0.963 0.438 0.277 0.234 0.387 0.794 0.360 0.312 0.404 0.858 1.141 0.561 0.213 0.269 0.644 1.074 0.432 0.265 0.289 0.600 0.983 0.435 0.829 0.756 0.885 1.265 1.353 1.557 0.417 0.300 0.833 1.667 1.250 1.000 0.618 0.690 0.671 1.197 1.810 1.343 0.682 0.693 0.750 1.237 1.650 1.430 0.345 0.342 0.325 0.494 0.886 0.454 0.317 0.331 0.413 0.873 1.145 0.564 0.298 0.323 0.357 0.743 1.304 0.509 0.320 0.332 0.357 0.679 1.116 0.500 SANDSAGE 1985 1986 1987 1988 1989 1990 0.621 0.838 0.169 0.904 1.047 0.860 0.375 0.500 0.250 1.000 1.250 0.395 0.650 0.250 1.194 0.857 0.600 0.566 0.793 0.189 0.945 1.007 0.852 COMBINED 1985 1986 1987 1988 1989 1990 0.421 0.470 0.127 0.616 0.815 0.486 Grass-forb Combined 0.315 0.339 0.434 1.355 1.159 0.473 0.2n 0.281 0.204 0.834 1.008 0.365 1985-90 F VALUE 1989-90 0.41 0.57 0.09 0.07 1985 and 1986 were both pretreatment years. 3 0.335 0.367 0.224 0.863 0.969 0.474 �202 1.2 1.1 1'"\ e 1.0 "0 0.9 >I- 0.8 (/l Z W 0.7 .,!. D.S o 0." v 0 0.6 :::t W :::t D.l 0.2 0.1 0 85 86 87 S8 89 90 YEAR Fig. 7. Height-density (dm) of residual grass-forb vegetation from 1985 (pretreatment) to 1986-90 (post-treatment) within the 1985 burn and control sites, Tamarack Prairie, Colorado. 1.0 D.9 O.B 'E' '0 V 0.7 ~ 0.6 VI Z W 0 O.S I I- ::I: 0.4 W 0.3 l!) ::I: 0.:2 0.1 0 IS 88 8B 87 89 90 YEAR Fig. 8. Height-density (dm) of residual grass-forb vegetation from 1985-86 (pretreatment) to 1987-90 (post-treatment) within the 1986 combined burn and control sites, Tamarack Prairie, Colorado. �203 attributed to greater precipitation subsequent to treatment. All grass-forb HDI's declined from 1989 to 1990 in direct relation to respective precipitation amounts (Fig. 8). The impacts of fire did not persist. Comparison of HDI's among the 4 controls showed similar trends for all except the 1-84 site in 1989 (Fig. 9). This was attributed to a local precipitation deficiency there in 1988 (Snyder 1990). 1.2 1.1 1985 1.0 1\ E lJ 0.9 U >I:- 0.8 0.7 (f) Z W 0 0.6 1986 I lI o 0.4 W I 0.3 0.2 "- 0.1 3-84 a 84 85 86 87 88 89 90 YEAR Fig. 9. Height-density (dm) of residual grass-forb vegetation among 1984 through 1986 controls from 1984 through 1990, Tamarack Prairie, Colorado .. Sand sagebrush within the 1985 and 1986 burns, like that in the 1984 burns, recovered more slowly than other herbaceous vegetation (Tables 5 and 6). However, comp arLs on among years showed sage recovered more rapidly in the 1985 and 1986 burns than in 1984 burns, apparently in response to increased precipitation. An initial rapid recovery was noted, but subsequent growth was slower. Three of the 4 control groups showed similar sage growth patterns from 1987 through 1990 (Fig. 10). However, growth of sage within burn 1-84, like that of grass-forb vegetation, was markedly reduced in 1989 due to deficient precipitation in 1988. Sandsage, within the 1986 burns, showed little recovery in 1990 from the previous year (Table 6). �ZU4 2.0 1\ 'l'-. '\ 'f~. '\ r I (\ E 1.6 I I 'o , >- I I 1.2 o I I 3-84 I l- ./ I l!) W I •.. •.. 0.8 '\ ~./ •.. .•.. I \ ./ .•.. ./ j \ ,~ \. \ /I"""'__ 1/ iJ _,....-- \ \\ // , i;1/ \ \\ 1/ I \ \\ .:i , tt V) Z // I l- w I \ 1/ I u ,'I \ \ '- \ , /1 /1 /1 1/ 1986 ••.•.. I \ ./ \ 1-84 ,7 /~ 1985 0.4 84 85 86 87 88 89 .90 YEAR Fig. 10. Height-density (dm) of sandsage among 1984 through 1986 controls from 1984 through 1990, Tamarack Prairie, Colorado. Crown Cover Analysis Point frame sampling of vegetati~n crown cover was completed in August 1990 within both the 1985 and 1986 burns ~nd their respective controls. Tables 710) .. Trends among major species and combined groups of species from 1984 (pretreatment) through 1990 for the 1985 burns and controls varied (Table 11). Both 1984 and 1985 samples were pretreatment within the 1986 burns (Table 12). Bouteloua gracilis.--Fire enhancement of blue grama occurred within both the 1985 and 1986 burns until 1988. No change occurred after that other than blue grama remained greater on burns. This may have resulted from removal of dead vegetation, or an actual sustained increase may have occurred. Stipa comata.--Needle-and-thread grass was severely depressed by the 1985 burn for several years, but full recovery was evident by late summer 1990. Trends were less evident within the 1986 burns. Pretreatment indices in 1984 and 1985 did not agree. Fire apparently depressed needle-and-thread and the treatment and control transects showed similar trends from 1988 to 1990. �205 Table 7. Crown cover (point frame total), species composition (X), and frequency of occurrence of vegetation within treatment transects on 3 sites burned in 1985, Tamarack Prairie, August 1990. Crown cover 2 3 Category/species Totals Bare ground Dead vegetation 262 557 289 767 263 213 814 1,537 Bouteloua gracilis ~ comata Sporobolus cryptandrus Calamovilfa longifola Andropogon hallii Agropyron smithii ~ virgatum Oryzopsis sp. Cyperus & Carex spp. Artemisia filifolia Opuntia sp. 262 399 125 225 24 9 308 858 366 308 54 894 1,509 633 575 4 47 3 204 13 324 252 142 42 94 8 109 1 9 64 23 Ambrosia psilostachya Artemisia ludoviciana Tradescantia occidentalis Evolvulus nuttalianus Erigeron sp. Psoralea tenuiflora Physalis subglabrata Thelesperma megapotimicum ~ leptophylla Mentzelia nuda Liatris sp-.- 54 20 17 108 Salsola kali Helianthus'petiolaris Croton texensis Chenopodium album Conyza canadensis Pepidium densiflorum Cirsium sp. Eriogonum ~ Ameranthus sp. Lactuca sp. Polygonum sp. 82 51 rr 5 5 6 9 2 3 16 2 6 10 1 87 9 11 12 9 5 3 47 9 1 12 23 2 2 5 C~. Freq. Occur. 94 109 1 16 315 36 17.91 30.22 12.68 11.52 3.44 1.88 2.18 0.02 0.32 6.31 0.72 0.94 1.00 1.00 0.94 0.65 0.76 0.12 0.06 0.29 0.76 0.35 182 17 5 11 9 2 4 17 2 16 1 3.65 0.34 0.10 0.22 0.18 0.04 0.08 0.34 0.04 0.32 0.02 0.59 0.18 0.06 0.29 0.06 0.06 0.18 0.29 0.06 0.18 0.06 181 74 11 16 59 23 1 1 1 1 5 3.63 1.48 0.22 0.32 1.18 .0.46 0.02 0.02 0.02 0.02 0.10 0.65 0.29 0.29 0.53 0.53 0.29 0.06 0.06 0.06 0.06 0.06 1n �Crown cover (point frame total), species composition (X), and frequency of occurrence of Table 8. vegetation within 3 1985 control sites, Tamarack Prairie, August 1990. Crown cover Category/species 2 3 Totals C~. Freq. Occur. Bare ground Dead vegetation 238 589 358 653 415 246 1,011 1,488 Bouteloua gracilis Stiea £2!!!!!.!! Sporobolus cryptandrus Calamovilfa longifola Andropogon hallii Paspalum stramineum Agropyron smithii Muhlenbergia sp. Aristida sp. Koleria cristata Panicum virgatum Amual spp. Cyperus & ~ spp. Artemisia filifolia Opuntia sp. 257 490 166 142 20 5 9 267 883 180 157 23 146 95 161 54 5 3 7 1 2 670 1,468 507 362 150 5 68 3 7 1 2 1 14 495 62 13.83 30.30 10.46 7.47 3.10 0.10 1.40 0.06 0.14 0.02 0.04 0.02 0.29 10.22 1.28 1.00 1.00 1.00 0.88 0.41 0.06 0.71 0.12 0.12 0.06 0.06 0.06 0.41 0.82 0.41 99 3 6 24 5 1 21 15 2 2 2 2.04 0.06 0.12 0.50 0.10 0.02 0.43 0.31 0.04 0.04 0.04 0.59 0.18 0.12 0.35 0.06 0.06 0.24 0.29 0.12 0.06 0.06 747 33 25 2 8 3 9 5 1 6 9 1 15.42 0.68 0.52 0.04 0.17 0.06 0.19 0.10 0.02 0.12 0.19 0.02 0.65 0.59 0.24 0.06 0.12 0.12 0.12 0.12 0.06 0.12 0.12 0.06 63 107 1 140 7 1 6 64 10 7 291 45 Ambrosia psilostachya Artemisia ludoviciana Tradescantia occidentalis Evolvulus nuttalianus Erigeron sp. Psoralea tenuiflora Physalis subglabrata Thelesperma megapotimicum Sphaeralcea coccinea lygodesmia ;uncea Mentzelia nuda 39 14 46 3 Salsola kali Chenopodium album Pepidium densiflorum Helianthus petiolaris Croton texensis Eriogonum !Q!l!:!!! Conyza canadensis Euphorbia sp. Cirsium sp. Polygonum sp. Ameranthus sp. ~sp. 10 13 5 6 11 2 13 5 1 19 6 2 1 n7 18 2 2 9 1 2 10 2 18 1 3 6 5 7 3 1 6 9 �207 Table 9. Crown cover (point frame total), species composition (X), and frequency of occurrence of vegetation within treatment transects on 3 sites burned in 1986, Tamarack Prairie, August 1990. Crown cover Category/species 2 3 Totals Compo Freq. Occur •. 0.95 1.00 1.00 0.74 0.53 0.74 0.26 0.05 0.05 0.05 0.37 Bare ground Dead vegetation 535 614 176 410 427 705 1,138 1,729 Bouteloua gracilis Stipa ~ Sporobolus cryptandrus Calamovilfa longifola Andropogon hallii Agropyron smithii Aristida sp. Panicl.J1l virgatl.J1l Muhlenbergia sp. Oryzopsis sp. Cyperus & ~ spp. 5n 384 219 147 148 9 8 128 344 151 278 33 24 633 517 131 301 15 37 2 1,338 1,245 501 726 196 70 10 23 23 8 1 6 3 6 8 1 15 25.05 23.31 9.38 13.59 3.69 1.31 0.19 0.43 0.15 0.02 0.28 Artemisia filifolia ~sp. 233 5 10 1 62 37 305 43 5.71 0.81 0.79 0.53 161 47 1 15 2 22 3 8 1 13 33 3.01 0.88 0.02 0.28 0.04 0·.41 0.06 0.15 0.02 0.24 0.62 0.47 0.16 0.05 0.26 0.05 0.32 0.16 0.05 0.05 0.05 0.32 343 45 72 34 31 13 5 4· 1 2 3 1 6.42 0.84 1.35 0.64 0.58 0.24 0.09 0.07 0.02 0.04 0.06 0.02 0.84 0.16 0.75 0.32 0.26 0.42 0.11 0.11 0.05 0.05 0.05 0.05 Ambrosia psilostachya Artemisia ludoviciana Tradescantia occidentalis Evolvulus nuttalianus Lathyrus polymorphus Erigeron sp. Thelesperma megapotimicum Haplopappus spinulosus Ipomoea leptophylla Mentzelia nuda SphaeralceS-COccinea 42 119 47 10 2 5 1 5 Salsola kali Helianthus petiolaris Chenopodium album Conyza canadensis Croton texensis Pepidil.J1l densiflorum Euphorbia sp. Eriogonum.!!!l!:!!! ~sp. Cirsium sp. Kochia scoparia Amaranthus sp •. 22 12 13 2 8 8 3 1 6 1 17 93 11 14 18 1 11 1 8 1 13 16 228 33 48 18 5 4 2 3 2 3 �208 Table 10. Crown cover (point frame tota'L), species composition (X), and frequency of occurrence of vegetation within 3 1986 control sites, Tamarack Prairie, August 1990. Crown cover 2 3 Category/species Totals C~. Freq. Occur. Bare ground Dead vegetation 340 814 125 400 355 882 820 2,096 Bouteloua gracilis 604 484 101 350 19 2 127 500 93 182 27 5 6 2 359 690 192 365 47 21 5 21 7 1 15 39 1,090 1,674 386 897 93 28 11 21 7 1 15 41 20.60 31.63 7.29 16.95 1.76 0.53 0.21 0.40 0.13 0.02 0.19 0.77 1.00 1.00 1.00 0.95 0.53 0.37 0.16 0.11 0.05 0.05 0.11 0.16 6 3 300 37 462 63 8.73 1.19 0.68 0.68 2 5 68 6 1 6 6 2 3 1 98 8 4 11 1 3 5 7 3 3 1.85 0.15 0.08 0.21 0.02 0.06 0.09 0.13 0.06 0.06 0.26 0.21 0.11 0.16 0.05 0.11 0.21 0.11 0.05 0.05 269 6 5 32 15 13 2 3 10 2 3 5.08 0.11 0.09 0.60 0.28 0.25 0.04 0.06 0.19 0.04 0.06 0.42 0.11 0.16 0.32 0.16 0.26 0.11 0.05 0.11 0.05 0.05 !!le~ Sporobolus cryptandrus Calamovilfa longifola Andropogon h!l!ii Agropyron smithii Paspalum stramineum Muhlenbergia sp,: Orvzoes issp. Koleria cristata Annual grass spp. Cyperus & ~ spp. Artemisia filifolia Opuntia sp. 156 23 Ambrosia Dsilostachya Artemisia ludoviciana Tradescantia occidentalis Evolvulus nuttalianus lathyrus polymorphus Physalis subglabrata Thelesperma megapotimicum Sphaeralcea coccinea lygodesmia juncea Mentzelia nuda 30 Salsola kal i Helianthus petiolaris Croton texensis Chenopodium album Eriogonum .!!!:!m!!! Conyza canadensis Euphorbia sp. Pepidium densiftorum Polygonum sp. Gaura A'iiiaranthus sp. 61 4 3 5 15 203 2 5 16 2 11 1 5 7 1 3 1 2 3 3 1 3 10 2 3 �209 Table 11. Crown cover (point frame mean/transect) for selected species and species groups among pre- and post-treatment samples within combined 1985 burns and their controls, Tamarack Prairie, Colorado, 1984-90. Species/category Bouteloua gracilis Stipa comata Sporobolus cryptandrus Calamovilfa .longifolia Andropogon hallii Agropyron smithii Selected warm season Total warm season Total cool season Artemisia filifolia Comb. peren. forbs Combined annual forbs Bare ground Dead vegetation 1985 28.5 31.4 4.8 36.8 1.7 0.6 39.4 72.7 32.1 22.5 4.4 4.1 30.9 260.1 21.2 27.7 21.1 54.5 5.1 1.8 61.8 104.0 29.5 8.2 3.4 2.8 110.3 170.1 Treatment 1986 20.6 48.2 21.1 58.8 9.6 10.4 70.5 112.2 58.6 11.9 5.7 3.5 90.7 145.1 1988 1990 26.6 36.2 19.8 47.0 11.2 11.6 63.1 109.5 47.9 18.0 17.5 15.5 31.1 189.6 52.6 88.8 37.2 33.8 10.1 5.5 50.4 140.2 94.3 18.5 15.6 22.1 47.9 90.4 20.2 43.1 23.5 35.4 9.1 8.9 44.6 88.2 52.0 34.6 12.7 20.9 42.7 176.0 39.4 86.4 29.8 2l.3 8.8 4.0 28.5 99.5 90.4 29.1 10.6 49.9 59.5 87.5 Control Bouteloua gracilis Stipa comata Sporobolus cryptandrus Ca1amovilfa longifolia Andropogon hallii Agropyron smithii Selected warm season Total warm season Total cool season Artemisia filifolia Comb. peren. forbs Combined annual forbs Bare ground Dead vegetation apretreatment. 30.8 31.3 8.1 33.1 2.1 2.2 35.9 74.8 33.5 24:7 2.9 3.6 42.2 249.3 21.9 55.2 22.7 28.5 4.1 3.5 32.8 77 .4 58.7 22.6 2.1 3.5 47.1 217.9 10.5 .67.2 22.1 26.4 .4.6 11.0 31.1 63.8 78.2 23.8 4.2 4.2 67.7 187.9 �210 Table 12. Crown cover (point frame mean/transect) for selected species and species groups among pre- and post-treatment samples within combined 1986 burns and their controls, Tamarack Prairie, Colorado, 1984-90. Species/category Boute1oua gracilis Stipa comata Sporobo1us cryptandrus Ca1amovi1fa longifo1ia Andropogon ha11ii Agropyron smithii Selected warm season Total warm season Total cool season Artemisia fi1ifo1ia Comb. peren. forbs Combined annual forbs Bare ground Dead vegetation 1985 37.3 42.5 10.3 26.9 1.9 28.9 76.5 46.1 18.1 7.2 5.2 39.5 234.2 36.1 40.0 13.7 25.3 2.4 4.3 27.6 77 .4 44.2 16.2 4.7 1.6 41.1 241.4 Treatment 1986 38.1 38.5 24.5 44.9 6.8 9.5 51.7 114.3 47.9 7.9 15.4 3.2 182.4 57.2 1988 1990 42.5 38.4 19.0 45.9 8.4 10.1 54.4 115.9 48.5 14.8 25.9 12.9 46.9 163.6 70.4 65.5 26.4 38.2 10.6 3.7 49.7 146.5 69.2 16.1 16.1 29.2 59.9 91.0 31.0 48.7 19.4 54.4 2.8 4.2 57.6 108.0 52.9 29.7 11.7 12.2 34.7 177 .0 57.4 &8.1 20.3 47.2 4.9 1.5 52.1 129.8 89.2 24.3 7.5 18.9 43.2 110.3 Control Bouteloua gracilis Stipa comata Sporobo1us cryptandrus Ca1amovi1fa longifo1ia Andropogon ha11ii Agropyron smithii Selected warm season Total warm season Total cool season Artemisia fi1ifo1ia Comb. peren. forbs Combined annual forbs Bare ground Dead vegetation apretreatment. 40.6 28.1 4.6 39.5 0.6 40.1 85.3 29.1 14.4 5.1 3.1 28.9 263.9 34.6 52.1 14.8 33.8 1.1 1.8 34.9 84.3 53.7 19.3 3.0 1.3 32.6 226.6 18.0 61.5 15.3 37.2 1.2 5.3 38.3 71.6 66.8 22.6 6.3 2.3 46.6 204.8 �211 Sporobo1us cryptandrus.--Sand fire within the 1985 burns. the 1986 burns. dropseed showed no evidence of being impacted by Short-term enhancement may have occurred within Ca1amovi1fa 10ngifo1ia.--The 1985 burns markedly stimulated growth of pra~r~e sandreed for 2 years. A similar trend was evident within the 1986 burns, however, data for the 2nd post-treatment year were lacking and enhancement did not continue to the third year (1988). There was no evidence that impacts of fire were more than temporary. Hot, dry weather in June was suspected as the reason reduced growth of prairie sandreed occurred in 1990 (Tables 11 and 12). Andropogon hallii.--Although sample sizes were small, sand b1uestem increased following fire within both the 1985 and 1986 burns. It also increased within the controls indicating lack of grazing may be enhancing the species. Warm-season Combinations.--Sand bluestem crown cover was combined with pra~r~e sandreed and switchgrass as selected warm-season grasses (Tables 11 and 12). A strong fire enhancement was noted, however, sandreed dominated this combined group so trends followed that species (Fig. 11). When total warm-season grasses were combined (blue grama and sand drop seed were added), the data show fire stimulated a pronounced short-term increase with retention of a lower rate of enhancement through 1990 (Tables 11 and 12). 80 8S BURN IU W (/) z « 0: 60 86 I- CONTROL "(f) / ..............•. l86 BURN I « IT ...• -/ 40 w > « ...•.....••. , - -.... / ..... ...•••...•.. _,...,.-:/•.... -'-' --- ........._._ ..•. ./ .~ ;;.t-........ "- .•... / . / .......•../ W 19 ---..." / / / \. / ./. / \. " \. " / " ~.~..7··- - -._ - - " .•••...... 85 CONTROL " "" " 20 84 85 86 88 90 YEAR Fig. 11. Crown cover (point frame) of selected warm-season grasses within the 1985 and 1986 burn and control ·sites from 1984 through 1990, Tamarack Prairie, Colorado. Pretreatment samples were obtained in 1984 (1985 burns) and 1984-1985 (1986 burns). �Sand Sagebrush.--Sand sagebrush was markedly reduced by 1985 and 1986 burns. Some recovery was noted in 1988 and 1990, but recovery to pretreatment levels was not attained (Tables 11 and 12). Perennial Forbs.--Combined perennial forbs showed no immediate effect of fire within the 1985 burns, but evidence they were stimulated by fire was indicated within the 1986 burns (Tables 11 and 12, Fig. 12). Increases in perennial forbs during both 1988 and 1990 were noted within the 1985 burns. Western ragweed (Ambrosia psi1ostachya), a warm-season perennial, showed evidence of fire enhancement within the 1985 and 1986 burns in 1988 (Snyder 1989). This increase was only partially sustained in 1990. Evidence of enhancement was not noted within the 1984 burns. 30 ...........•.... 25 I- / o W « ... . ..... (f) z r .! 20 85 BURN ......•. 0:: ..:"' I- . .•.. ". . . . <, (f)' l- 15 ,;<----_" I B6 BU'N W o « 0:: 10 W > « 5 /" "-~--""""// ~<.i>. ••••• •. l· -------.-" 85 CONTroL o 84 85 86 88 90 YEAR Fig. 12. Crown cover (point frame) of perennial forbs within the 1985 and 1986 burn and control sites from 1984 through 1990, Tamarack Prairie, Colorado. Pretreatment samples were obtained in 1984 (1985 burns) and 1984-1985 (1986 burns). Annual Forbs.--Annual forbs showed no post-tr~atment effects of fire based on crown cover sampling within the 1985 and 1986 burns (Tables 11 and 12). I~ 1990 annual forbs within the 1985 and 1986 controls increased much more than within the burns. Russian thistle (Saisola kali) was primarily responsible, increasing dramatically within some transects, especially within thin stands of need1e-and-thread. �213 Bare Ground and Dead Vegetation.--The amount of bare ground was near pretreatment levels in 1988 within the 1985 and 1986 burns and remained there through 1990 (Tables 11 and 12). Dead vegetation and litter declined for 2 years following the 1985 burns and remained in unison with that in the controls during both 1988 and 1990 sampling periods. Sampling was not conducted in 1987 within the 1986 burns and it is not known if a 2nd year of reduction occurred, but near full recovery was noted by 1988. Trends toward less dead vegetation were apparent within both the burned and control transects. Possible responsible factors include sampling when vegetation was greener in later years, slight changes in sampling procedure, or a combination. Revegetation and Renovation Treatments Tillage-Reseeding.--The height-density of residual vegetation, primarily switchgrass, was sampled beginning in early spring 1987 after the 2nd (1986) growing season. The average HDI was 1.8~ dm among 12 transects. Visual obstruction readings increased to 4.44 dm in 1988 and 4.38 dm in 1989, but declined to 3.55 dm in 1990. Although a downward trend was noted, HDI's continued to average above other vegetation within the Tamarack Prairie. Point-frame sampling of vegetation types within the 1985 revegetation strips in late summer 1990 continued to show dominance by tall, warm-season grasses (Table 13). Standing residual (primarily switchgrass) was the most frequently recorded item during the last 3 years. Increases in annual forbs were noted in 1990 but ot~er native grasses remained suppressed by taller grasses. The amount of bare ground continued to decline. Table 13. Crown cover (point frame total) among vegetation groups from 1985 through 1990 within 12 1985 revegetation transects, Tamarack Prairie, Colorado. Vegetation/category Bare ground Dead vegetation/litter Dominant native grasses Lesser grasses and sedges Seeded tall grasses Sandsage and cactii Perennial forbs Annual forbs 1985 1986 1987 1988 1990 804 212 217 79 311 6 22 76 812 156 226 37 475 10 12 0 278 372 183 21 833 8 2 31 120 620 98 13 829 15 20 13 107 394 138 14 850 14 14 197 Renovation of Interseeded Tracts.--The HDI of residual grass-forb vegetation declined from the 1988 peak in both the tillage-herbicide treatment and control transects during early spring 1990 (Table 14). However, the HDI within the treated area remained far greater than that within the control (f < 0.01), indicating treatment effect continued ~hrough the 1989 growing season. �L..14 Table 14. Mean height-density (dm) of grass-forb, sandsage, and combined cover from pre- (1986) to post-treatment (1987-90) intervals between a tillage-herbicide and untreated control within a previously interseeded location, Tamarack Prairie, Colorado. Year Tillage-herbicide Control Grass-forb 1986 1987 1988 1989 1990 0.382 0.314 1.554 1.388 1.043 0.393 0.271 0.551 0.449 0.375 Sandsage 1986 1987 1988 1989 1990 1.234 0.227 1.136 1.143 0.750 0.696 0.608 1.268 0.781 1.154 Combined 1986 1987 1988 1989 1990 0.579 0.306 1.525 1.373 1.038 0.544 0.375 0.677 0.520 0.544 Crown cover sampling in late summer 1990 also showed that bluestems and switchgrass continued to be enhanced by the early spring 1986 tillageherbicide treatment (f < 0.005), whereas blue grama, needle-and-thread, and other native grasses remained suppressed (Table 15). Prairie sandreed was apparently neither enhanced nor hindered by treatment. This tall, warm-season native grass survived the tillage-herbicide treatment because it was deeprooted like the bluestems and switchgrass. Perennial forbs, likewise, have shown little long-term effect of treatment (Table 15). In 1990, tall, warmseason species showed little change from the preceding year. Tillage-herbicide renovation was applied to numerous other interseeded tracts by management personnel in 1986-87. Pretreatment HOI data were lacking, but within a sample of 10 sites, the average HOI of standing residual was 2.71 dm in 1989. Their HOI increased to 3.41 dm in 1990 and was comparable with that (3.55 dm) within the strips revegetated in 1985. �215 Table 15. Average crown cover/transect (0.01-m2) of selected species and species groups from pre- (1985) to post-treatment (1986-90) intervals within tillage-herbicide renovation of an interseeded site and control, Tamarack Prairie, Colorado. 1985 1986 1987 1988 1989 1990 Andropogon/Panicum Calamovilfa longifolia 13.7 11.3 24.2 12.4 36.3 13.8 39.8 11.2 47.1 13.8 48.3 12.4 Bouteloua, !!ie!, etc. Perennial forb 17.6 1.5 5.4 0.6 6.4 1.2 6.8 1.6 9.9 2.6 12.5 4.9 16.4 10.7 17.1 2.2 16.6 10.6 16.8 1.7 22.1 10.2 19.8 3.4 24.6 8.1 20.4 1.7 33.9 8.5 27.6 1.2 32.2 9.0 35.0 2.3 Species/group Tillage-herbicide Control Andropogon/Panicum Calamovilfa longifolia Bouteloua, Stipa, etc. Perennial forbs F Values Andropo90n/Panicum Calamovilfa longifolia Bouteloua, !!ie!, etc. 8e < 1985-90 1989-90 42.198 1.44 34.828 4.08 1.42 0.04 0.005. Strip Spraying of Sandsage.--Much of the residual sagebrush that had remained standing after being killed in 1985 deteriorated in 1989, contributing little to the HOI in early spring 1990. Sandsage was the primary obstruction, 37.2% of the time in 1987, 24.1% in 1988, 22.7% in 1989, and 8.2% in 1990. The HOI of grass-forb vegetation declined to 0.49 dm in 1990 in a pattern similar to that within the 1985 and 1986 burns (Figs. 7 and 8). Grass-forb vegetation within the site sprayed in 1985 and burned in 1986 (Table 16) also showed markedly lower HOI's in spring 1990. Point frame sampling of crown cover, conducted in late May 1990 (Table 17) was compared with pretreatment and other preceding years. Grasses gradually increased with needle-and-thread being among the main benefactors. Increases in 1990 probably resulted from favorable spring moisture in contrast to 1989 (Table 17). Sandsage was beginning to show minor recovery and prickly pear cactus, already abundant, steadily increased. Combined perennial forbs also increased, except in 1989, when dry weather persisted in spring. Increases in total species contacts were observed. Monitoring of Prairie Grouse Radio-marked Birds from 1989.--0ata obtained in 1990 supplemented that obtained from 6 males and 7 female greater prairie-chickens radio-marked with solar-powered transmitters in spring 1989 in the vicinity of the Tamarack Prairie (Fig. 13). Among that group, 2 nested on the Tamarack Prairie, 1 nested a few meters to the south, and the others nested at more distant locations. However, none of the hens was confirmed to have successfully nested. Among the 7 hens, 3 (probably 4) were killed by predators while �216 Table 16. Mean height-density (dm) within the 1985 sandsage spray site during 1986 to 1990 post-treatment intervals and preburn (1986) to post-burn (1987-89) intervals within a portion burned in 1986, Tamarack Prairie, Colorado. Year N Transects Grass-forb Sands age Combined 1985 SANDSAGE SPRAY SITE 1986 1987 1988 1989 1990 2 11 11 11 11 0.246 0.272 0.613 0.675 0.494 0.879 0.800 1.127 0.960 1.021 0.468 0.469 0.737 0.740 0.538 0.713 0.333 1.250 0.404 0.129 1.133 0.911 0.63~ SANDSAGE SPRAY - 1986 BURN 1986 1987 1988 1989 1990 4 4 4 4 4 0.279 0.122 1.131 0.911 0.639 nesting and 3 survived until spring 1990. Among the latter, 2 survived through summer 1990. One nested successfully in 1990 but the other was unsuccessful. The 3rd hen was monitored as she visited Lek 1 in April, but her weak signal was not detected again and her survival and nesting success remain unknown. Among 6 males radio-marked in spring 1989, 4 were killed by predators in spring, 1 apparently slipped its harness, and 1 survived to mid summer after which it could not be located (probably due to a weak signal). Monitoring of Transplanted Prairie-Chickens.--Management personnel trapped 23 greater prairie-chickens in Yuma County in April 1990 and released them on the east half of section 15 (Township 10 N, Range 48 W) in the northeast part of the Tamarack Prairie (Fig. 13). Releases were made at a proposed 1ek site (R 1ek) and tape-recorded calls were used in an unsuccessful attempt to retain the males at the 1ek. Eight (4 of each sex) were equipped with 10-g batterypowered transmitters which had a 1-year life expectancy. These transmitters, attached with an elastic loop around the lower neck, worked well and seemed to cause little stress to the grouse. The transmitters, previously tested as operating, were not tested at time of release. The signal from 1 hen was not picked up in subsequent monitoring. Either the transmitter quit working while the hen was captive or she left the area immediately after release. The other 3 hens moved about 1.6 km south of the release site (near M lek, Fig. 13) where 2 (possibly 3) nested on the Tamarack Prairie. One was killed by a raptor and an abandoned nest (possibly hers) was later found in the vicinity. The other 2 hens successfully nested and raised their broods in the southeast part of the Tamarack Prairie. They shifted to the south in fall and their signals were eventually lost prior to early winter. �.217 Table 17. Crown cover (point frame total) of vegetation and ground cover within 11 random transects during pre-(1985) and post-treatment (1986-90) spring intervals in the June 1985 herbicide-treated sandsage spray tract, Tamarack Prairie, Colorado. Vegetation/cover Bare ground Dead vegetation Perennial grass Bouteloua gracilis Stipa ~ Sporobolus cryptandrus Calamovilfa longifolia Other perennial grasses Annual grass BrOlllJstectorun Festuca sp. Artemisia filifolia (alive) A. filifolia (dead) ~ & Echinocereus spp. Perennial forbs Ambrosia & Artemisia spp. Tradescantia occidentalis Lathyrus polymorphus Psoralea tenuiflora .Evolvulus nuttalianus Phlox andicola All iun textile MeiitZelia nuda Leucocrinum-montanun Penstemon angustifolius Thelesperma megapotimicun Cymopteris mont anus Abronia fragrans Erigeron sp. Liatris sp. Total perennial forbs Annual forbs Croton texensis Chenopodiun albun Pepidiun & Lesguerella sp. Miscellaneous annual forbs Pretreatment 1985 1986 1987 402 1,425 529 1,324 536 1,083 142 194 34 51 4 148 510 46 65 15 70 Post-treatment 1988 1989 1990 387 990 472 1,207 454 1,028 312 425 106 53 19 307 683 161 120 15 311 563 108 124 15 327 722 103 87 23 117 4 116 7 38 10 436 112 1 259 0 287 0 210 4 201 5 124 44 50 62 83 75 97 5 18 114 55 6 4 2 12 1 2 2 2 1 9 77 7 17 121 1 1 8 1 6 12 45 2 29 22 123 1 1 6 1 107 8 1 1 19 1 1 6 1 6 3 11 1 223 3 24 3 1 96 3 154 156 76 4 1 1 6 1 4 4 6 178 2 1 9 8 �"'d"1 •... N Ii 1-" IIIOQ 1-" , Ii 1-" 00 t-' R 49 W - ~ po- H ""1:1 W (I) W R 48 'II - R 47 'II ~p t-' \Or-' 13 \0(1) o~ ~ !;;. ~ III 8"d Ii III 1-" Ii 1-" CD I g. CrAMARACK PRAIRIE ~. .> 19 ~ M 7< X X '"""W ~---- o X * 25 12 :>;"' CD ::l 27 29 ::l III rt >- ~ () i 25 tTl If) N t-' o 19 23 * 9 1-" (I) 13 ~7< * 31 35 en 1, 33 0 ~ III 31 35 ,. 2 X rt i 1-" o ::l III >- 5 1 1-" 7< ::l 16 I 3 1 ~ X t5 'z Ii (I) t-' III rt 7 11 9 X *14 1-" o §N 11 ROAD 46 ::l rt o rt ::T (I) t-:l ~ III Ii III o :>;"' LI '13 7< X LEK GEND t 3,2 KM # NEST Il 0 1 SCALE 2 mi . j~ l 13 , I lJ 12 �219 Two of 4 radio-marked males died soon after release, probably to predation. One was recovered a short distance east of the release site and the other was found to the south near the Tamarack Prairie boundary. One surviving male became an active resident at lek 1 and the other was active at lek 2 through the remainder of the spring. They remained near «3 km) their respective leks through the remainder of summer and fall. Radio-marked Birds From 1990.--Trapping, banding, and instrumenting of resident prairie grouse using leks closely asso~iated with the Tamarack Prairie continued in spring 1990. Lek monitoring and searches for new leks also continued and 2 new leks were found and monitored. One new lek (lek 16, Fig. 13) contained 1 greater prairie-chicken, 2 or more plains sharp-tailed grouse and several male hybrid crosses of the 2 species. Several males were observed at lek 9 near the Tamarack Prairie border in early spring 1990. However, use suddenly diminished prior to initiation of trapping and only 1 male remained through spring. Two males began using a mowed lek (M lek) on the Tamarack Prairie near lek 9 (Fig. 13). Only 1 male prairie-chicken and 1 sharp-tailed grouse remained at lek 12 through spring 1990. Trapping was not conducted on either lek in 1990. Thus, prairie-chicken activity associated· with the Tamarack Prairie seemed diminished for unknown reasons in 1990. Thirteen resident greater prairie-chickens (7 hens and 6 males) were trapped and banded at leks 1 and 14 (Fig. 13). All hens and 1 male were instrumented with 7-g battery-powered transmitters (attached by a small elastic cord around the lower neck) with a life expectancy of 6 months. These transmitters worked well, seemed to have little impact on the grouse, and most transmitters operated for 7 to 8 months. One hen, whose solar transmitter no longer operated properly, was a retrap from the previous year. She was radio-marked with a new transmitter. Two hybrid males were trapped, banded and released. and 1 female sharp-tailed grouse were radio-marked. Two of 3 trapped males Total radio-marked grouse at the end of the April 1990 trapping effort included 10 female and 5 male prairie-chickens and 1 female and 2 male sharptailed grouse (Table 18). These data do not include 2 hens, 1 transplanted and 1 radio-marked in 1989, whose signals were not subsequently located. One hen (hen 921), instrumented in 1989, but not trapped in 1990, was subsequently located on her nest in late May 1990 adding to the monitored population through late spring and summer 1990. Most hens (7 of 8), that survived through summer 1990, successfully nested (Table 18). One-third of the 12 hens were killed by predators. Three of 7 males died including 2 transplants that died soon after release to predation or other causes. The height-density of grass-forb and sandsage vegetation was sampled at, and proximal to, nest sites and compared with samples taken at 2 random locations within a 65-ha area surrounding each nest. The average HOI of grass-forb vegetation at 10 nest sites was 0.622 dm, whereas that at 20 random sites averaged 0.567 (f> 0.10). The HOI of sandsage averaged 2.53 dm at nest sites compared to 2.14 dm at random locations (f> 0.10). There was no difference for either grass-forb or sandsage vegetation and similar findings were obtained when 1989 data were included. Among the 10 nests found in 1990, all but except 1 were partially concealed by sandsage. �220 Table 18. Transmitter I"IUItIer Radio-marked prairie grouse data, northeastern Logan County, Colorado, 1990. Species Age Survival days Resident! transplant 25a 200+ 200+ 15a R R R R R R R T T T R R Successful nest Nunber of nests Totals Hatched 2 6 6 2 12 12 8 0 11 8 ? 8 12 8 13 Eggs FEMALES 906 918 949#1 968 977 987 998 057 121 141 959b 921 PC PC PC PC PC PC PC PC PC PC STG PC 928 937 949#2 019 037 099 178 PC STG STG PC PC PC PC J A A A J A A J rr 200+ 200+ 25a A 152+ 200+ 163+ 100+ J J J 200+ 185+ 30a A A A No Yes No No No Yes Yes No Yes Yes Yes Yes 1 2 12 14 13 ~ A A J A r 185+ 14a 200+ R R R T T T T aKnown mortality. bHen 921 was radio-marked in 1989 and found incubating in May 1990. Radio-marked hens, that had successfully nested, were flushed in late August in an attempt to estimate brood size. However, by that date some broods had merged with others and some hens apparently no longer were with broods. Therefore, meaningful brood size data were not obtained. Although surviving radio-marked transplanted hens remained on the Tamarack Prairie and raised their broods there, little use of the property was noted by prairie grouse resident to the south. One hen, from 1ek 1, moved onto the Tamarack Prairie but was killed prior to nest initiation. Two other hens temporarily shifted to the .Tamarack Prairie after their nests were predated, but moved back to previously established home ranges within a few days. All hens with broods raised them within several kilometers of their respective nest sites. Several hens used grain field-rangeland interspersions near lek 14, but primarily resided in rangeland. Nearly all birds shifted south in fall to the vicinity of 1ek 14 where grain fields existed. The transplanted hens showed evidence of similar moves although their wintering residence was not found. �221 LITERATURE CITED . Snyder, W. D. 1986~.· Sandsage-b1uestem prairie renovation. Job Progress Rep., Colorado Div. Wi1d1., Wi1d1. Res. Rep., Fed. Aid Proj. 01-03-045 (W37-R). Apr.:475-498. 1986Q. Sandsage-b1uestem prairie renovation. Job Progress Rep., Colorado Div. Wi1d1., Wi1d1. Res. Rep., Fed. Aid Proj. 01-03-045 (W-37-R). Apr. :499-525. 1987. Sandsage-b1uestem prairie renovation. Job Progress Rep., Colorado Div. Wi1d1., Wildl. Res. Rep., Fed. Aid Proj. W-152-R. Apr. :331356. __________ 1988. Sandsage-bluestem prairie renovation. Job Progress Rep., Colorado Div. Wildl., Wi1d1. Res. Rep., Fed. Aid Proj. W-152-R. Apr. 3:395 -421. 1990. Sandsage-bluestem prairie renovation. Job Progress Rep., Colorado Div. Wildl., Wildl. Res. Rep., Fed. Aid Proj. W-152-R. Apr. :173202. Prepared by '%£&.)z!J.t!J) IJ¥ Warren D. Snyder Wildlife Researcher C �.~ './ �JOB FINAL REPORT . State of: Colorado Project: W-152-R Work Plan: Job Title: 21 : Job _4_ Feeding ecology of Sharp-shinned Hawks and nest site characteristics of accipiters in Colorado Period Covered: Author: Upland Bird Research 01 January 1987 through 31 December 1990 Suzanne M. Joy Personnel: C. E. Braun, R. W. Hoffman, Colo~ado Division of Wildlife; R. T. Reynolds, U.S.D.A. Forest Service; R. L. Knight, S. M. Joy, Colorado State University ABSTRACT Feeding ecology of 11 sharp-shinned hawk (Accipiter striatus) pairs and nest site characteristics of 14 sharp-shinned hawk, 4 Cooper's hawk (A. cooperii), and·2 northern goshawk (A. genti1is) nests in mature aspen, conifer, and mixed aspen-conifer habitats in southwest Colorado were investigated during 1988 and 1989. Small birds (i - 21g) and mammals (i- 4lg) comprised 91 and 9% of 513 prEy items identified, respectively. Unique plucking and feeding habits of individual pairs accounted for differences in total prey and avian prey numbers among nests. More (>50%) prey items were found during the nestling than incubation or fledgling stages. Although birds were consumed more often than mammals during all breeding stages, mammalian prey frequency progressively increased from incubation through fledgling. Numbers of avian prey at the nest sites increased 164% from incubation to the nestling stage. Nearly 60% of the birds eaten during nestling and fledgling stages were young of the year. This was reflected in a shift in median prey (bird) weight from 17.4 g during incubation to 12.1 g during the nestling stage. Hawks .at nests dominated by aspen habitat (n - 5) consumed fewer mammals (6.8% of diet) than hawks at 1 nest surrounded by coniferous habitat (28.3% of diet). Conifer habitats appeared to have less foraging value compared to mature aspen types. Avian prey were consumed in proportion to their size availability and species composition in habitats surrounding nests, whereas certain taxa and size classes of mammals were preferentially preyed upon. The data suggest that sharp-shinned hawks are vulnerable to predation and require the protective cover provided by conifers at the nest. Foraging success in aspen habitats may also influence nest site location for this species. Whereas northern goshawks appear to require relatively open, old-growth coniferous forests for foraging, as well as large aspen trees for nesting, Cooper's hawks primarily used aspen dominated habitats for foraging and nesting. Because accipiters require specific stand characteristics for nesting, active and potential nest sites should not be modified by timber harvests. �RECOMMENDATIONS 1. Insular patches (1-14 ha) of mature conifers (preferably species with a dense crown such as Engelmann spruce or subalpine-fir) on northerly exposures ·should be maintained within continuous stands of aspen to provide nesting habitat for sharp-shinned hawks. - 2. The insular patches of conifers should occur within 400 m of water and should be surrounded by 1-2 km2 of mature and or mixed conifer-aspen types with no more than 20% of the area in openings of < 10 ha. 3. The maximum distance between conifer patches within aspen types should be < 2 km. No roads should occur within 400 m of these insular conifer stands and no timber harvest should occur within 1 km. 4.. Active accipiter nest sites should be marked and protected. 5. Because sharp-shinned hawks forage opportunistically in a variety of habitats, limited timber harvest may occur in these habitats provided the density of small birds is not significantly altered. Small « 10 ha), irregular shaped cuts are preferred over large, block shaped cuts. Openings created by timber harvest should be no more than 60 m wide. �225 ACKNOWLEDGMENTS The Colorado Division of Wildlife (CDOW) and the U.S. Department of Agriculture Forest Service (USFS) provided partial funding for this project through a cooperative agreement. I received additional support from the Hawk Mountain Sanctuary Association (1989 Hawk Mountain Research Award) and Colorado State University (Colorado Graduate Fellowship). The financial support of all was appreciated greatly. I thank R. L. Knight, my major adviser, for advice, critiques, many open discussions, and his willingness to take on a microbiologist for a .wildlife study. For encouragement, constructive comments, and sharing his knowledge of and enthusiasm for accipiters, I thank.R. T. Reynolds. I thank G. C. White for statistical advice (without which Chapter 1 would have been a statistical nightmare) and lessons in hypothesis testing. B. Van Horne opened my mind to new ideas and provided critical comments on both my study design and thesis for which I am grateful. I thank R. W. Hoffman for many candid discussions, and for helpful comments on CDOW reports, study plan, and thesis. C. E. Braun also provided constructive comments on CDOW reports and the thesis. I am indebted to my field assistants for their hard work, unwavering enthusiasm, and friendship. S. Bedard, M. Kralovek, B. Rusk, and S. Severs greatly enriched my time in the field. For use of museum collections, I thank M. Bogan and C. Ramotnik of the U.S. Fish and Wildlife Service (USFWS) in Fort Collins, CO, and R. �c. Banks of the USFWS in Washington, D.C. I also thank C. Dove and R. Laybourne for invaluable help in improving my skills as a feather detective. I thank W. D. Shepperd of the USFS for permitting me to use his core counter and for many discussions on aspen ecology. I thank B. Cade of the USFWS for help in running MRPP. I am grateful to my fellow graduate students for the many coffee breaks, long talks, and parties although I didn't make it to all. I thank my family for their love and encouragement during the good and bad times, and for believing in me. Finally, I am especially grateful to S. C. Frye, my husband, for his moral support, love. and friendship . • �227 TABLE OF CONTENTS Page ABSTRACTOF THESIS ....•............................................ iii ACKNOWLEDGMENTS v LIST OF TABLES ix LIST OF FIGURES Chapter 1. x FEEDING ECOLOGYOF BREEDINGSHARP-SHINNEDHAWKSIN COLORADO Study 1 Area 2 Methods ........•..•..•........................................... Prey Collection Diet Composit;ion .......•....................................... 4 5 Foraging Zone Resource Use and Availability Diet 4 7 with Breadth Respect " to Habitat , 7 10 Results 10 Prey Collection 10 Diet Compos Led en 11 Fc'r'ag l ng Zone Resource Diet 18 Use and Availability with Respect Breadth to Habitat 18 20 Discussion 25 Prey Collection and Possible Data Bias Diet Composition .•........................................... 25 25 �TABLEOF CONTENTS(Continued) Foraging Zone .....•..................•....................... Resource Use and Availability Diet Chapter with 28 Respect to Habitat Breadth 29 30 Management Implications 31 Literature 31 2. Cited •............................................... NESTINGHABITATOF ACCIPITERS IN SOUTHWEST COLORADO Study Area 38 Methods .....•.............. Results ' ...•................................. 39 ...........•............................ Discussion 36 " 41 .........•............................................ 47 Management Implications 52 Literature 53 Cited .•.....•......•................................. APPENDICES...............•....... " Appendix 1 .................•.•............... Appendix 2 ...•.................................................. ~........•.... " 57 58 62 �229 LIST OF TABLES Table Page 1.1 Maximum likelihood log-linear model for numbers of total (avian and mammalian) prey and avian prey in the diet of breeding sharp-shinned hawks in southwest Colorado, 1988-89 12 1.2 General linear model analysis of variance for total (avian and mammalian) prey and avian prey biomass in the diet of breeding sharp-shinned hawks in southwest Colorado, 1988-89 16 1.3 Dominant, secondary, and limited habitats surrounding nests of sharp-shinned hawks in southwest Colorado during 1988-89 breeding seasons , 19 1.4 Taxonomic ranking of mammalian prey consumed by sharp-shinned hawks in dominant, secondary, and limited habitats surrounding nests in southwest Colorado during 1988-89 21 1.5 Size ranking of mammalian prey consumed by sharp-shinned hawks in dominant, secondary, and limited habitats surrounding nests in southwest Colorado during 1988-89 22 1.6 Food-niche breadth values of breeding sharp-shinned hawks in Alaska, Colorado, Oregon, and Utah based on numbers of prey species, genera, and size-class categories used in each study ...24 2.1 Characteristics of accipiter nest sites in southwest Colorado, 1988-89 0 •••••••••••••••••••••••••••••••• 45 �230 LIST OF FIGURES Figure Page 1.1 Gunnison and Grand Mesa National forests in Colorado 3 1.2 Proportion of total (birds and mammals) and avian prey consumed during incubation, nestling, and fledgling stages at nests of sharp-shinned hawks in southwest Colorado, 1988-89 13 1.3 Proportion of total and avian prey consumed during incubation, nestling, and fledgling stages by sharp-shinned hawks in southwest Colorado, 1988-89 14 1.4 Mean biomass (vertical bar) and SE (vertical line) of avian and mammalian prey during incubation, nestling, and fledgling stages at nests of sharp-shinned hawks in southwest Colorado, 1988-89 ..17 1.S Prey (avian and mammalian) availability and use curves of sharp-shinned hawks in southwest Colorado, 1988-89 23 2.1 Relative location of goshawk (NOGO), Cooper's hawk (CORA), and sharp-shinned hawk (SSRA) nests in 1 region of Gunnison and Grand Mesa National forests, Colorado, 1987-89 43 2.2 Aspect of sharp-shinned hawk, Cooper's hawk, and goshawk nest sites in southwest Colorado, 1988-89 46 Directional exposure of sharp-shinned hawk, Cooper's hawk, and goshawk nests in southwest Colorado, 1988-89 48 2.3 �231 Chapter 1 FEEDING ECOLOGY OF BREEDING SHARP-SHINNED HAWKS IN COLORADO In Colorado, sharp-shinned hawks (Accipiter striatus) occur in quaking aspen (Populus tremuloides) and conifer (Abies, Picea, Pseudotsuga)-dominated forests. Aspen stands comprise over 25% of the state's 4.58 million ha of commercial timberland (Green and Van Hooser 1983) and most (> 70%) of these stands are in mature (70-120 yr) and old-growth (120+ yr) age classes (Shepperd 1990). Management practices such as clear-cutting, thinning, and removal of invading conifers have been prescribed to encourage regrowth of aspen stands, especially in areas where aspen is seral to conifers (Jones et al. 1985). Reynolds (1989) suggested that differences in foraging habitats used by sharp-shinned hawks may be more closely related to prey availability than to tree species composition or habitat structure. Alterations in forest structure and/or composition may affect bird and mammal populations, which may in turn affect reproductive performance of sharp-shinned hawks. Small birds (10-30 g) associated with forest canopies comprise approximately 95% of the hawk's diet (Craighead and Craighead 1956, Storer 1966, Reynolds and Meslow 1984). Flack (1976) demonstrated that aspen canopies in 6 western states, including Colorado, contained 41% (818 of 1,975 individuals counted) of all breeding birds in the 4 nesting guilds he defined (canopy, shrub, hole, �232 and ground). Birds nesting in the canopies of mature aspen forests in western Colorado were 53% more abundant than in the other nesting guilds (Flack 1976). The upper-most stratum of Colorado's aspen forests thus appears to contain abundant food resources for foraging hawks. To understand the potential effects of aspen harvests on sharp-shinned hawks, pre-harvest data on hawk/forest relationships and hawk use of prey relative to prey availability in aspen and conifer forests are needed. During 1988-89r I examined the food habits of breeding sharp-shinned hawks in mature aspen, conifer, and mixed aspen-conifer forest types. Sizes and numbers of prey delivered to nests were compared among nests, nesting stages, and between prey taxa. Relationships between diet composition and resource availability were examined. Diet breadths of sharp-shinned hawks breeding in montane and subalpine regions of 4 states, including Colorado, were reviewed to learn if hawks in Colorado used prey similarly to sharp-shinned hawks elsewhere in the U.S. STUDY AREA The study was conducted in Gunnison and Grand Mesa National forests (Fig. 1.1) in Gunnison, Delta, and Mesa counties, Colorado. Large (> 500 ha) and small (100-200 ha) climax aspen stands and conifer communities existed in these forests between 2,750 and 3,200 m elevation. Principal conifers were subalpine fir (~. lasiocarpa), Engelmann spruce (l. engelmannii), and blue spruce (l. pungens). precipitation (primarily snow) averaged 50.7 cm (Natl. Oceanic and Annual �,, ,, , ,, .. _.....-- GRAND MESA N. F. , ,, , , ,, , , N .,. ,, ,, ,, .. , , ,, , ,, ,, , ,, ,, , ,, , , ,, GUNNISON N. F. ,, ,, .. , ,, , ,, ,, , • DENVER ...--------1 .. .. .' o .. ' 50 100 -» ' ' .. .' .' ' .' -» COLORADO Fig. 1.1. Gunnison and Grand Mesa National forests in .Colorado. Slash marks delineate approximate area searched. N W W �geranium (Geranium richardsonii) , Barbey larkspur (Delphinium barbeyi), white-flowered peavine (Lathyrus leucanthus), and monkshood (Aconitum columbianum). Prominent low-growing plants included elk sedge (Carex geyeri), wild strawberry (Fragaria ovalis), yellow prairie violet (Viola nuttallii), and fringed brome (Bromus ciliatus). The shrub component consisted primarily of snowberry (Symphoricarpos spp.), chokecherry (Prunus virginiana), and true mountain-mahogany (Cercocarpus montanus). Conifer understories were dominated by low-growing herbs including heart-leafed arnica (Arnica cordifolia), field horsetail (Eguisetum (Vaccinium myrtillus) and kinnikinnik (Arctostaphylos uva-ursi). Plant names follow Weber (1976). Portions of the forests were interspersed with privately-owned lands used for livestock grazing. In addition, sheep and cattle foraged freely in the study area during July and August. Consequently, most of the study area had been grazed by the end of each field season. METHODS Prey Collection Prey remains (flight and contour feathers, bills, and feet of birds; tails, fur, skull fragments, and feet of mammals) were collected �235 from nesting areas once a week. As changes in nesting stage (incubation, nestling, or fledgling) approached, prey remains were collected every 2 days. Nesting-stage changes were often indicated by changes in behavior of breeding hawks (e.g., females became increasingly aggressive prior to and during egg-hatch). Boundaries of nesting areas were delineated based on observations of prey exchanges, plucking, feeding, and roosting behavior of pairs around nests. were recorded from blinds placed near nests. Pair activities The area of activity near the nest tree, exclusive of foraging areas, was defined as the nest site. Nest sites were searched completely for prey remains during each nest visit. Prey remains were collected from nest sites until young dispersed or nests failed. Diet Composition Parts of uneaten prey were sorted by nest, collection date, size, color, and texture. Avian remains were reconstructed and compared with National Museum of Natural History (Washington, D.C.) specimens, identified, and counted following Reynolds and Meslow (1984). Muddy or matted feathers were washed with Ivory Snow and dried with compressed air before being identified (R. Laybourne, U.S. Fish and Wildlife Service, pers. commun.). Single prey feathers were not included, as they may have been from molting birds. Mammalian prey were processed similarly at the U.S. Fish and Wildlife Service museum in Fort Collins, Colorado. Adult prey weights were obtained from Hall (1946), Armstrong (1972), and Dunning (1984), or from museum specimens (APPENDIX 1). Prey were identified to species where possible. Weights of prey �236 identified to genera level were estimated by averaging weights of all species within the genus that occurred in the study area (Reynolds and Mes10w 1984). "Unknown birds" and "unknown sparrows" were assigned weights based on the mean weight of birds and mean.weight of sparrows in the study area, respectively. Sex-specific weights were used when sex of prey was known; otherwise, the mean weight of both sexes was assigned. Avian prey were classified to age (adult, subadu1t, or nestling) by plumage and amount of sheathing on flight feathers (Reynolds and Meslow 1984). Adults were defined as individuals with unsheathed or complete feathers, whereas, partly sheathed feathers were classified as from subadu1ts. Remiges on subadult birds emerged faster than retrices, which allowed further age classification. Subadults with unsheathed remiges and partly sheathed retrices were assigned the adult weight because they were nearly grown; subadu1ts with partly sheathed remiges and retrices were assigned thre£-quarters of their adult weight. Feathers from nestlings were defined as completely sheathed and assigned one-half the adult weight. Only adult weights could be assigned to mammals. Prey frequencies were compared among nests and nesting stages, between adult and young (subadult and nestling) avian prey, and between avian and mammalian taxa using a maximum likelihood log-linear model (MLLM) (CATMOD; SAS Inst. Inc. 1987). General linear models (GLM) (GLM; SAS Inst. Inc. 1987) were used to test for differences in total prey (avian and mammalian) and avian prey biomass among nests and nesting stages, between adult and young avian prey, and between avian and mammalian taxa. Data collected from unsuccessful nests (n - 5) were �237 excluded from the analyses. I tested the null hypothesis of no difference among the independent effects. All analyses were evaluated at the a - 0.05 significance level. Multi-response permutation procedure (MRPP; Mielke and Berry 1982, Biondini et al. 1988) was used to test for differences in distribution of avian and mammalian prey weights among nesting stages. from all nests (n - 11) were used in this procedure. Prey remains Distributional differences were examined further in pairwise tests of equal variances using Moses' rank-like procedure (Hollander and Yolfe 1973). In addition, nonparametric tests of equal means (analysis of variance) and medians (Yilcoxon rank-sum test) were performed with SAS (NPARlYAY; 1987). In all analyses, I tested the null hypothesis of no difference among independent effects. the a All pairwise comparisons were evaluated at 0.05/3 - 0.017 (Bonferroni inequality) level. Foraging Zone I compared prey numbers taken from each of 5 foraging zones [ground-shrub, shrub-canopy, canopy, aerial, and generalist (Reynolds and Meslow 1984)] (APPENDIX 1) using K2 goodness of fit tests (Steel and Torrie 1980) to examine if hawks in Colorado foraged equally in all zones. Birds were assigned to the zone in which they were observed most often. Birds not observed, but found in remains at nests, were assigned zones following Reynolds and Meslow (1984:APPENDIX 1). Resource Use and Availabili~y wi~h Respect to Habitat Prey use was compared with prey availability in 3 forest cover levels (dominant, secondary, and limited) surrounding nests to learn if �prey were used in proportion to their occurrence in these habitats. Forest composition within a 2-km radius of each nest was ascertained from aerial photographs (1:24,000). Sharp-shinned hawks forage primarily within an area of 1.5 km from the nest (Reynolds 1983); therefore, a 2-km radius was presumed to enclose most foraging areas used by the hawks. Cover types comprising ~ 50% of the area surrounding nests were termed "dominant". forest types occupying> "Secondary" habitats were defined as 5% to ~ 49% of £oraging areas. Cover types making up ~ 5% of surrounding areas were termed "limited". Because hawks were presumed to not forage extensively in limited cover types, tests of prey use versus availability in these forests were designed to assess differences in prey availability between restricted and more "common" (dominant and secondary) cover types. That is, were there differences in prey use between these habitat levels that might explain the low occurrence of limited types within the hawks' foraging radius? The null hypothesis that prey were equally used in each habitat level was tested using program PREFER (Johnson 1980); prey items were classified by size and taxon. each habitat level. A separate analysis was performed for PREFER examined the relationship between ranks of prey use and availability for each nest to identify if breeding hawks used prey in proportion to their availability in the 3 habitat levels. Use and availability data were paired on individual years to eliminate possible differences in prey abundance between years. Waller and Duncan's (1969) mUltiple comparison procedure was used in PREFER to assess relative component "preferencen• Analyses in PREFER were limited to sizes and taxa of prey likely to be consumed by sharp-shinned hawks so that number of nests would exceed �239 the number of size or taxon classes and produce a more robust analysis. Program PREFER was dimensioned for I (number of nests) - 1 (number of prey sizes or families) + 1 degree of freedom, and J ~ 1. Avian prey were assigned weights (Dunning 1984) and partitioned into 6 size classes following Storer (1966) (APPENDIX 2). Mammalian prey were assigned weights (Armstrong 1972, 1975) and partitioned into 9 size classes (Storer 1966). Mammalian prey in classes 9 (166-216 g), 6 (64-'91.1g), and 2 (8-15.6 g) were excluded from analyses because they were not found in remains nor counted during surveys (APPENDIX 2). Ten .avian and 5 mammalian taxonomic categories (families) were also used in the analyses (APPENDIX 2). To ensure that number of families did not exceed number of nests, families of avian prey in surveys, but containing S 2 consumed individuals at all nests were excluded from analyses. To further reduce the number of families, Sittidae and Certhiidae were combined based on their similar behavior. Weasels (Mustelidae) were excluded from analyses because they are unlikely to be consumed by sharp-shinned hawks. Finally, prey use was compared with the total range of "available" bird and mammal sizes surveyed in the area to identify overall patterns in prey size use by the hawks. Quantitative estimates of avian and small mammal availability during the 1988 and 1989 breeding seasons were provided by R. T. ,Reynolds (U.S. For. Serv., unpubl. data). Bird abundances (raw counts) were estimated between mid-June and mid-July using variable circular-plots on 15 40-ha plots (D. M. Finch and R. T. Reynolds, U.S. For. Serv., Study Plan RM-420l.l-l). Mammal abundances (raw counts) were estimated between late-July and late-August with baited live and pitfall traps on 15 IOxlO grids (15 m trap spacing) (total trap nights - �~4U 27,OOO/yr) (R. T. Reynolds and D. M. Finch, U.S. For. Serv., Study Plan RM-420l.l-2). The 15 plots (9 in aspen, 3 in conifer, 3 in mixed aspen-conifer cover types) were systematically sampled each year. Survey data were assumed to reflect (1) approximate abundances of bird and mammal populations present throughout the hawks' breeding season in each forest type and (2) approximate prey availabilities perceived by the hawks. Diet Breadth Food-niche breadths were calculated for breeding sharp-shinned hawks in Alaska (Clarke 1984), Colorado (this study), Oregon (Reynolds and Meslow 1984), and Utah (D. L. Fischer, unpubl. data) to examine geographical variation in resource use (Levins 1968:43). Calculations were based on the use coefficient, ~i1' which represents the proportion of food resource i used by consumer 1. Prey were grouped by species, genus, and size classes (Storer 1966). RESULTS • Prey Collection Eleven sharp-shinned hawk nests were studied during May 1988 (4) and 1989 (7). Most (91%) nest sites (exclusive of foraging areas) were within small (1-14 ha), insular conifer stands surrounded by aspen or mixed aspen-conifer stands. forest. One nest was in a contiguous conifer No nests were depredated in 1988 allowing collection of prey from 4 nest sites during all nesting stages. Five of 7 nests were depredated in 1989; thus, prey remains were only collected from 2 nest sites during all nesting stages, 7 nest sites during incubation, and 4 �241 nest sites during fledgling stages. A total of 686 prey items was identified, including 52 species and 39 genera of birds and 11 species and 10 genera of mammals (APPENDIX 1); 513 of these.prey (i.e, those from successful nests) were used in MLLM and GLM procedures. Mammals were found at 10 of 11 nests and birds were found at all nests. Diet Composition Prey Frequency. of the diet. Small birds comprised the largest (91.1%) portion The proportion of mammals in the diet ranged from 1.2 to 11.8% for nests dominated by aspen (n - 5) to 28.3% for 1 nest z, do~inated by conifers (indicated in a nest by taxon interaction; Table 1.1). Prey'numbers varied interactively with nest and nesting stage; more prey were consumed during the nestling period at the majority of nests (67%) than during other stages (Table 1.1, Fig. 1.2). Numbers of prey also differed interactively with prey taxon and nesting stage (Table 1.1). During all breeding stages, hawks. fed primarily on birds (Fig. 1.3); however, the proportion of mammals in the diet increased from 7.8 to 16.5% between incubation and fledgling stages. Voles (Clethrionomys, Microtus, and Phenacomys) comprised over 60% of the mammals eaten. Voles were also counted more often (n - 1,077) during surveys than other diurnal or mostly diurnal small mammals (Sorex, n 69.2;Tamias, n - 478; Thomomys, n - 18; and Zapus, n 37). Numbers of birds consumed differed with independent effects: nests, nesting stages, and prey ages (Table 1.1). Of the 466 birds used in MLLM analyses, 86 (18%) were found during the fledgling period,' 144 (31%) were during incubation, and 236 (51%) were during the nestling period. Overall, adults comprised a larger proportion (61%) of the �242 Table 1.1. Maximum likelihood log-linear model for numbers of total (avian and mammalian) prey and avian prey in the diet of breeding sharp-shinned hawks in southwest Colorado, 1988-89. Interactions are indicated by an "x". Source of variation J.2 df f. Total Prey Nest "5 74.07 < 0.001 Breeding stage- 2 4.50 0.105 Nest x Breeding stage 10 37.07 < 0.001 Taxon (Birds, Mammals) 1 89.83 < 0.001 Nest x Taxon 5 25.02 < 0.001 Breeding stage x Taxon 2 7.39 0.025 10 8.41 0.589 GOODNESS OF FIT Avian Prey Nest 5 183.14 < 0.001 Breeding stage 2 49.59 < 0.001 10 23.93 0.008 Age (Adult, Youngb) 1 32.81 < 0.001 Nest x Age 5 0.31 0.379 Breeding stage x Age 2 54.96 < 0.001 Nest x Breeding stage GOODNESS OF FIT 10 .i!lJ 8.41 -Incubation, nestling, and fledgling stages. bSubadults and nestlings. ,,'_., 0.838 �243 I OINCUBATION [ill NESTLING IFLEDGLINGI TOTAL PREY 224 53 85 61 34 56 100 80 I- 60 ::l 40 Z o o > m > w a:: c, I- 20 o AVIAN PREY 204 55 84 38 30 55 1 2 3 4 5 6 1..00 Z w 80 o a:: w 60 Q. 40 20 o NEST Fig. 1.2. consumed Proportion during sharp-shinned columns of total (birds and mammals) incubation, hawks nestling, in southwest are prey counted/nest. and fledgling Colorado, 1988-89. and avian prey stages at nests of Numbers above �244 TOTAL PREY 100% I• 100 BIRDS 0 MAMMALS 236 86 eo I- Z ::l o o 60 40 > 20 m o > W100 a: n. 36 12 AVIAN PREY 139 I OADUL T {8JYOUNG I I- eo Z W 60 o a:: w a. 48 130 40 20 5 o INCUBA TION NESTLING FLEDGLING BREEDING STAGE Fig. 1.3. Proportion of total and avian prey consumed during incubation, nestling, and fledgling stages by sharp-shinned hawks in southwest Colorado, 1988-89. Prey were partitioned by taxon (birds, mammals); avian prey were partitioned by age (adult, young). numbers are above each column. Prey I �245 avian diet than young (39%). The number of avian prey at individual nests varied interactively with nesting stage (Table 1.1). As with total prey numbers, more avian prey were found during the nestling than incubation or fledgling stages at the majority (67%) of nests. Age differences in avian numbers also occurred among nesting stages (Table 1.1). During incubation, sharp-shinned hawks fed primarily on adult birds (Fig. 1.3). Young birds (subadults and nestlings) became increasingly more important in the diet as the breeding season progressed. Yellow-rumped warblers (Dendroica coronata) appeared most often in the avian prey remains (n - 78), followed by American robins (Turdus migratorius) (n - 52), white-crowned sparrows (Zonotrichia leucophrys) (n - 44), and dark-eyed juncos (~hyemalis) Prey Biomass. The mean weight of all prey items differed between taxa (Table 1.2); mammals comprised almost twice the biomass ~ ± SE - 41.1 ± 3.3 g) of birds hawks' diet. voles. (n - 41). (n - (n - 47, 466, ~ ± SE - 20.9 ± 0.8 g) in the Over 54% of the prey biomass of mammals was contributed by Fifty percent.of the avian biomass was comprised of yellow-rumped warblers, American robins, white-crowned sparrows, and dark-eyed juncos. Interactions in total prey biomass existed among prey taxa (birds, mammals), nests, and nesting stages (Table 1.2, Fig. 1.4). The null hypothesis of no difference in avian prey biomass among main effects or interactions was not rejected (Table 1.2). Prey-weight Distribution. The null hypothesis that avian prey weights came from a common distribution among nesting stages was rejected (E - 0.051). showed significant (E stages. Pairwise MRPP comparisons of the distributions 0.011) variation between incubation and nestling Differences in measures of distributional variance �Table 1.2. General linear model analysis of variance for total (avian and mammalian) prey and avian prey biomass in the diet of breeding sharp-shinned hawks in southwest Colorado, 1988-89. Interactions are indicated by an "x". Source of variation df SS Total Prey Nest 5 1,342.00 0.87 0.500 Breeding stage- 2 1,169.25 1. 90 0.151 10 4,199.25 1.36 0.195 Taxon (Birds, Mammals) 1 4,343.62 14.09 < 0.001 Nest x Taxon 5 1,328.34 0.86 0.506 Breeding stage x Taxon 2 1,054.51 1.71 0.182 8 3,993.77 2.59 0.025 3,·033.24 2.12 0.062 Nest x Breeding stage Nest x Taxon x Breeding stage Avian Prey Nest 5 Breeding stage 2 151.46 0.26 0.768 10 4,828.30 1.69 0.082 Age (Adult, Youngb) 1 171.18 0.60 0.440 Nest x Age 5 1,022.71 0.71 0.613 Breeding stage x Age 2 341.03 0.60 0.552 Nest x Breeding stage x Age 8 4,356.00 1. 90 0.158 Nest x Breeding stage -Incubation, nestling, and fledgling stages. bSubadults and nestlings. �o 60 '"' m INCUBA TION 1m NESTLING ~FLEDGLING '"'" >w a: o, LL 40 BIRDS 20 o C/) C/) « s oJ o 20 z « w 40 -m s ,...., r::: MAMMALS 60 80 1 2 4 3 5 6 NEST Fig. 1.4. Mean biomass (vertical bar) and SE (vertical line) of avian and mammalian prey during incubation, nestling, and fledgling stages at nests of sharp-shinned hawks in southwest Colorado, 1988-89. N .p. "-I �(dispersion), as well as mean weight between the 2 stages, were not detected [l ~ 0.017 (Bonferroni inequality) for all tests]. However, median avian weights differed (l< 0.001) between incubation and nestling stages. Median weight of birds taken during incubation was 17.4 g compared to 12.1 g during the nestling period. Median bird weight increased to 14.7 g during the fledgling period. Density distributions of mammalian prey weights did not differ (l - 0.323) among nesting stages. Foraging Zone Sharp-shinned hawks captured food with equal frequency from ground-shrub, shrub-canopy, and canopy foraging zones (Xl - 0.121, df - 2, f - 0.942). differentially (X2 - Other zones (aerial, generalist) were used 62.3, df - 1, l< 0.005), with more prey .taken from the generalist (124 items or 18% of total prey) than aerial (27 items or 4% of total prey) zone. Zone use appeared to reflect relative prey availabilities in each foraging layer (28, 24, 30, 16, and 2%, respectively). Resource Use and Availability with Respect to Habitat Habitat designations for each nest varied (Table 1.3). Avian prey sizes were used in proportion to their availability in dominant (l ~ 0.25) and secondary (l - 0.172) habitat types. Avian size use differed (l - 0.03?) from availability in limited cover types. Bird taxa were consumed in proportion to their occurrence in all habitats (0.15 ~ l ~ 0.25). �249 Table 1.3. Dominant, secondary, and limited habitats surrounding nests· of sharp-shinned hawks in southwest Colorado during 1988-89 breeding seasons. Cover typeh Nest Year Dominant Secondary Limited 1 1988 A M C 2 1988 A M C 3 1988 A M C 4 1988 C M A 5 1989 A M C 6 1989 A M C 7 1989 A M C 8 1989 A M C 9 1989 A M C 10 1989 M A C 11 1989 M C A ·Dominant - cover types comprising ~ 50% of foraging areas; Secondary - cover types comprising> 5% to ~ 49% of foraging areas; Limited - cover types comprising ~ 5% of foraging areas. hA (aspen), C (conifer), M (mixed aspen-conifer). �Sharp-shinned hawks appeared to select similarly among size classes and taxa of mammals (l~ 0.03 for all habitat designations) (Tables 1.4, 1.5). Dipodidae and Geomyidae were most used among taxa, and Sciuridae and Sorcidae were least used in all habitat categories. Muridae, which contained all vole species and 1 deer mouse, was used most closely in proportion to its availability in all habitats, i.e., it had the lowest absolute mean difference between ranks of use and availability among taxa. Highest ranked among weight categories of mammals were size classes 8 (125.0-166.0 g), 7 (91.1-125 g), and 4 (27.0-42.9 g); size class 1 (3.6-8.0 g) was least used. Among the total range of bird and mammal sizes occurring in the study area, sharp-shinned hawks used only smaller (logloweight 0.7-2.1 g) size classes (Fig. 1.5). Within these smaller classes, the hawks consumed avian prey in nearly equal proportion to their overall occurrence. A lack of congruence between availability and use curves for m£mma1ian prey confirmed that hawks concentrated foraging efforts on only a few sizes of mammals. Diet Breadth Sharp-shinned hawks in Colorado preyed more uniformly over a wider range of prey species than hawks in either Oregon or Alaska (Table 1.6). Genera of prey were selected more uniformly by hawks in Colorado and Oregon than in Alaska (Table 1.6). Niche-breadth values with respect to biomass did not appear to differ among hawks breeding in Alaska, Colorado, Oregon, and Utah (Table 1.6). �251 Table 1.4. Taxonomic ranking of mammalian prey consumed by sharp-shinned hawks in dominant, secondary, and limited habitats surrounding nests in southwest Colorado during 1988-89. Taxon classes and average difference between ranks (MRD) of use and availability are Taxonomic use differed (f $ 0.01) in listed from most to least used. all habitats. Cover typeDominant Taxon Secondary MRDb Taxon MRD Limited Taxon MRD Dipodidae -1.50 Dipodidae -1.40 Dipodidae -1.70 Geomyidae -0.90 Geomyidae -1.00 Geomyidae -0.70 Muridae -0.35 Muridae -0.35 Muridae -0.35 Sciuridae 0.80 Sorcidae 1.05 Sorcidae 1.15 Sorcidae 1.95 Sciuridae 1.70 Sciuridae 1.60 -Dominant - cover types comprising ~ 50% of foraging areas; Secondary - cover types comprising> 5% to $ 49% of foraging areas; Limited - cover types comprising $ 5% of foraging areas. bMean rank difference. Negative values indicate proportional use was greater than availability; positive values indicate proportional use was less than availability. �252 Table 1.5. Size ranking of mammalian prey consumed by sharp-shinned hawks in dominant, secondary, and limited habitats surrounding nests in southwest Colorado during 1988-89. Taxa and average difference between ranks (MRD) of use and availability are listed from most to least used. Taxonomic usage differed (l~ 0.03) in all habitats. Cover typeDominant Weight (g) (Size c Las s") Secondary Limited Weight (g) (Size class) MRDc Weight (g) (Size class) (8) -1.30 125.0-166.0 (8) -1.15 91.1-125.0 (7) -1.20 91.1-125.0 (7) -0.75 27.0-42.9 (4) -0.70 27.0-42.9 {4) -1.15 42.9-64.0 (5) -0.55 91.1-125.0 (7) -0.70 42.9-64.0 (5) -0.S5 27.0-42.9 (4) -0.65 42.9-64.0 (5) -0.55 125.0-166.0 (8) -0.20 lS.6-27.0 (3) 0.8S lS.6-27.0 (3) 1.1S 15.6-27.0 (3) 1.15 3.4-8.0 (1) 2.25 3.4-8.0 (1) 1.95 3.4-8.0 (1) 1.95 125.0-166.0 MRD MRD -Dominant - cover types comprising ~ 50% of foraging areas; Secondary - cover types comprising> 5% to ~ 49% of foraging areas; Limited - cover types comprising ~ 5% of foraging areas. bFo1lowing Storer (1966). during surveys were excluded. Sizes classes of mammals not counted CMean rank difference. Negative values indicate proportional use was greater than availability; positive values indicate proportional use was less than availability. �253 40 AVAILABLE o AVIAN PREY USED 30 ---8--- 20 > 0 Z W 10 :J o W a: 0 W 35 l<t 30 0.9 0.5 1.3 2.1 1.7 2.5 2.9 3.3 3.7 LL - > ..J ~4 , , , , PREY I I , , 25 I I W a: MAMMALIAN I I I I I 20 . , I 15 • , 10 I. 5 0 0.5 0.9 1.3 1.7 2.1 2.5 2.9 3.3 3.7 4.1 4.5 4.9 5.3 5.7 LOG PREY WEIGHT (g) Fig. 1.5. Prey (avian and mammalian) availability and use curves of sharp-shinned hawks in southwest Colorado, 1988-89. �254 Table 1.6. Food-niche breadth values of breeding sharp-shinned hawks in Alaska, Colorado, Oregon, and Utah based on numbers of prey species, genera, and size-class categories used in each study. Food-niche breadtha Location H nests Prey species (n) Prey genera (n) Size classesb (n) Source Alaska 14 12.95 (41) 8.37 (32) 3.28 (6) Clarke (1984) Colorado 11 21.73 (63) 18.11 (49) 3.37 (8) This study Oregon 14 12.67 (44) 15.52 (37) 3.53 (9) Reynolds and Meslow (1984) 3 C Utah C 4:49 (6) D. L. Fischer (Unpubl. data) ·Ca1culated per Levins (1968). bFo1lowing Storer (1966). CData unavailable. .. �255 DISCUSSION Prey Collection Schipper determination biased and Possible Data Bias (1973) and Snyder and Wiley based on prey remains and casts collected estimates of diet composition. were underepresented Reptiles, in diets of the birds (1973) also found that in harrier also underestimated. amphibians) (1976) showed that diet Because and invertebrates diet must be detected they studied. lower vertebrates possibility of detecting difficult nesting to find. arthropods, of stomach amphibians, Another consumed Schipper contents casts were difficult and reptiles of the sharp-shinned and in the or casts 1984). excluded Casts were small of stomach contents and birds were their presence and Meslow and therefore I could not determine Analysis 5% by number) these prey. Furthermore, stage because regurgitated. « or cast contents and insects (e.g., reptiles are rarely plucked, (Snyder and Wiley 1976, Clarke 1984, Reynolds stomach amphibians, (Circus) diets, mammals through analyses not analyze at nests gave I did the (0.2-0.7 cm) and to assign to a when they had been was impractical. However, appear to make up a small portion hawk diet (Snyder and Wiley 1976). possible. bias in the data includes prey that were plucked and/or away from the nest site. may not depict all possible Thus, diet compositions prey consumed reported here by the hawks. Diet Composition Although hawk's geographic patterns birds. prey-species composition varies range, most investigators in prey-size Small birds use. the sharp-shinned have observed Hawks in Colorado (10-30 g) also comprised across primarily similar consumed a large portion small (> 95%) of �256 the hawks' diet in Wyoming, Craighead 1956, Storer addition, sharp-shinned 1966, Clarke hawks sizes and taxa of mammals reflected Michigan, present and maintaining foraging young, efforts vulnerability density nest defense, or understory use were reflected avian prey ages, vegetation by changes nest-taxon-nesting incubation increased energy both parents adults or fledgling demands stage. (Snyder and Wiley nest leaving fewer remains prey numbers responded consumed in foliage in prey taxa, and only in a the nestling stages, which probably During 1976). reflected the fledgling Also, after young at the nest site. adept at predator more often than young stage, to declining fledged, to forage prey (1) and their own food and eaten it away from the corresponded to seasonal period fewer prey in response Temporal to the abundance in terms of when young birds hatched, became prey differences fewer prey to encourage may have caught and/or require with nests, in prey biomass delivered (2) females avian prey changes Temporal in prey numbers of producing In addition, with seasonal of growing young. may have delivered overall demands stage interaction. probably populations of sharp-shinned and self-maintenance More prey were found at nests during during on certain This probably patterns The energetic height. and by changes In to predation. that vary with nesting may vary temporally and 1984). preyed in the study area. stages. (Craighead and Mes10w successfully (Clarke 1984) have examined hawk prey use across nesting and Oregon 1984, Reynolds in Colorado size or taxon vulnerability Few studies Alaska, changes escape. during in and vulnerability fledged, Consequently, in prey availability. than mammals changes all nesting of and migrated hawks may have Although stages, birds were mammalian �257 prey frequency reduction increased between in bird numbers incubation in mammalian Sharp-shinned stages. of mammals, was responsible hawks fed primarily season; however, nestling birds consumed and nestling the proportion through of adult, subadult, changed with nesting almost entirely stages, on adult birds the ~roportion avian prey consisted stage. of adult birds. of young birds incubation consume more young prey during the nestling the tendency period. (17.4 g) and of hawks prey .. Others (Newton 1979, Geer 1982, Clarke 1984, Newton stage prey biomass 1.4.). mammals period differences fully open. vegetated in use of prey biomass a pattern At 2 nests dominated were consumed corresponded During mid-summer and small mammals foraging sharp-shinned hawks. with nest, was apparent by aspen of young and Marquiss taxa, and regarding (nests 3 and 6, Fig. only during the incubation to early summer ground-shrub with the appearance period. (Jul) , the understory (especially Aspen understory all remaining available throughout nests became those associated remained (Fig. 1.4), the nesting This (Jun) when aspen understory season. was not densely with the zone) may no longer have been available At nearly of in accipiters. (Table 1. 2. Fig. 1.4). use. to Thus, nesting hawks similar patterns coincides In addition, sharp-shinned nesting in Colorado incubation in the diet increased there was a shift toward lighter prey between (12.1 g) stages, which reflected incubation, Between period. nestling the and During 5-fold and remained high during the fledgling Despite for the prey frequency. breeding 1982) reported A found at nests during the latter nesting stage, rather than elevated numbers increase and fledgling to dense until late August. mammals were apparently �Several investigators (Snyder and Wiley 1976, Clarke 1984, Reynolds and Meslow 1984) reported that during incubation and nestling stages, male sharp-shinned hawks provide .most of the prey. Females begin to forage during the late-nestling stage and continue to make prey deliveries through the fledgling period. Although females weigh about 69% more than males (Dunning 1984), and thus have the potential to capture larger prey (Storer 1966), they do not appear to do so. I detected no difference in mean prey biomass among nesting stages (l - 0.151). One explanation for the absence of larger prey during late-nesting stages may be that males catch a large portion of the prey delivered by females. During late-nesting scages , males were occasionally observed transferring food to females away from the nest; females then flew toward their nests with the prey. Behavioral differences among sharp-shinned hawks may exist as some hawks plucked more prey at nests than other pairs. Alternatively, variation in prey detectability and vulnerability among foraging sites may have caused differences in prey numbers among nests. It appeared that hawks at nests dominated by aspen habitat consumed fewer mammals than at 1 nest surrQunded by mostly coniferous habitat; however, insufficient numbers of nests in conifer habitat precluded statistical comparison between habitat types. In the relatively open understory of a conifer forest, small mammals may be more vulnerable to sharp-shinned hawks than in densely vegetated aspen understories. Foraging Zone Sharp-shinned hawks in Colorado foraged in nearly equal proportion in the canopy, shrub-canopy, and ground-shrub layers of the forest. �259 Conversely, sharp-shinned hawks in Oregon concentrated foraging efforts in upper portions of the forest canopy (Reynolds and Meslow 1984). An interdependence between prey size and foraging-zone occurrence (Reynolds and Meslow 1984) may explain these patterns of zone use. Small birds in Oregon tended to occur in upper portions of the canopy, whereas in Colorado they were distributed evenly among ground-shrub to canopy layers of the forest. A higher proportion of mammals in the diets of hawks in Colorado (9%) versus Oregon « 5%) may have account~d for different levels of ground-shrub use between studies. Most (92%) mammals consumed by hawks in Colorado occurred in the ground-shrub layer of the forest; most (64%) mammals taken by hawks in Oregon were zone generalists or canopy dwellers (Reynolds and Meslow 1984). Habitat differences between Oregon and Colorado study areas may have caused differences in prey vulnerability, and hence prey availability, among foraging zones. Study sites in Oregon consisted primarily of dense, contiguous conifer or conifer-dominated mixed stands (Reynolds et al. 1982). These forests allow little light to penetrate to lower vegetation levels, which may result in sparse undergrowth. Conversely, aspen stands permit sufficient light to penetrate the canopy to support abundant shrub, herb, and forb growth (Mueggler 1985). Due to insufficient cover, fewer small birds and mammals may exist in lower vegetation levels of Oregon's conifer forests than in the well vegetated understory of Colorado's aspen forests. Resource Use and Availability with Respect to Habitat An absence of preference for specific bird sizes and taxa in dominant and secondary habitats indicated that hawks foraged �260 opportunistically in each habitat. In limited habitats, avian prey use differed from availability for size classifications but not for taxa, suggesting that prey-size abundance or vulnerability varied between limited and ncommonn (dominant and secondary) habitats. Sharp-shinned hawks nested in conifers, yet coniferous habitat comprised 82% of the limited cover types; mature aspen and mixed aspen-conifer comprised 73 and 82% of dominant and secondary habitats, respectively. Perhaps hawks selectively foraged in aspen or aspen-dominated forests because avian prey of suitable sizes were more available in these forests. Similar taxa of avian prey were apparently available in each habitat. The importance of small avian prey in the diet of sharp-shinned hawks is probably a function of accipiter body size and evolutionary adaptations that permit energetically efficient hunting (Reynolds 1972). A sharp-shinned hawk's small body size limits the size of prey that it can capture and subdue without injuring itself. Within this .prey-size limit, the hawk exploits the entire range of available avian prey sizes. Diet Breadth Niche-breadth values provide comparable estimates of the extent of specialization in food selectivity among populations of breeding sharp-shinned hawks. A wider range and greater equitability of prey species were used by sharp-shinned hawks in Colorado than in Oregon or Alaska. The same pattern was true for classes of prey genera for hawks in Colorado and Oregon versus Alaska. However, hawks in Alaska, Colorado, Oregon, and Utah used size classes of prey similarly. Sharp-shinned hawks thus appear capable of exploiting variable numbers of prey taxa, while they are restricted to a relatively limited r~nge of �261 prey sizes. reflect Hawks Taxon niche-breadth the relative in Colorado differences availability consumed among these regions may of prey in each habitat twice as many species studied. of mammals and 1.3 times as many species of birds as hawks in Oregon or Alaska. habitats species used by hawks richness MANAGEMENT and evenness than habitats hawks conifers; appeared however, Manipulative needed forests. In addition, layers of the forest canopy while foraging. habitats integrity conifers appeared to be important of mature aspen, conifer, the nesting sharp-shinned be performed in mosaics hawks. experimentally, Mature of these forests areas for sharp-shinned with mature for nesting. and mixed cover types are Until controlled to perpetuate hawks aspen and foraging value of these habitats aspen management forest perturbation should maintain suitable nesting D. M. Univ. Kansas 1975. Assoc., 1972. Printing of mammals Serv., Lawrence. Rocky Mountain mammals. Inc., Estes Park, CO. 174 pp. in Colorado. 415 pp. Rocky Mountain can and foraging in Colorado. Distribution to the LITERATURE CITED Armstrong, of they exploited to have more foraging value when compared studies to examine breeding greater prey in Oregon or Alaska. in Colorado used prey resources aspen and aspen-associated several contain IMPLICATIONS Sharp-shinned mature in Colorado may therefore Foraging Nature �Banks, R. C., R. W. McDiarmid, and A. L. Gardner. 1987. Checklist of vertebrates of the United States, the U. S. Territories, and Canada. U. S. Dep. Inter., Fish and Wi1d1. Servo Resour. Pub1. 166, Washington, D.C. 79 pp. Biondini, M. E., P. W. Mielke, and E. F. Redente. 1988. Permutation techniques based on euclidean analysis spaces: a new and powerful statistical method for ecological research. Coenoses 3:155·174. Clarke, R. G. 1984. The sharp·shinned hawk (Accipiter striatus viei11ot) in interior Alaska. Fairbanks. M.S. thesis, Univ. Alaska, 130 pp. Craighead, J. J., and F. C. Craighead, Jr. and wildlife. Hawks, owls, Stackpole Co. and Wi1dl. Manage. Inst., Harrisburg, PA and Washington, D. C. Dunning. J. B. 1956. 1984. American birds. 443 pp. Body weights of 686 species of North Western'Bird Banding Assoc. Monogr. 1. 38 pp. Flack, J. A. 1976. North America. Geer, T. A. 1982. Bird populations of aspen forests in western Ornitho1. Monogr. 19. 97 pp. The selection of tits Parus spp. by sparrowhawks Accipiter nisus. Green, A. W., and D. D. Van Hooser. the Rocky Mountain states. Resour. Bull. INT-33. Hall, E. R. 1946. Los Angeles. Ibis 124:159-167. 1983. U. S. Dep. Agric., For. Servo 127 pp. Mammals of Nevada. 710 pp. Forest resources of Univ. California Press, �263 Hollander, M., and D. A. Wolfe. methods. Johnson, D. H. 1973. 'Nonparametric statistical John Wiley & Sons, Inc., New York, NY. 1980. 503 pp. The comparison of usage and availability measurements for evaluating resource preference. Ecology 6:65-71. Jones, R. J., ,R. P. Winokur, and W. D. Shepperd. Management overview. P. Winokur, eds. Pages 193-195 in N. V. DeBy1e and R. Aspen: western United States. 1985. ecology and management in the U. S. Dep. Agric., For. Servo Gen. Tech. Rep. RM-119. Levins, R. 1968. Evolution in changing environments: theoretical explorations. Monogr. Pop. Biol. 2. Univ. Press, Princeton, N. J. Mielke, P. W., and K. J. Berry. some Princeton 120 pp. 1982. An extended class of permutation techniques for matched pai~s. Commun. Statist. 11:1197-1207. Mueggler, W.' F. 1985. Vegetation associations. N. V. DeByle and R. P. Winokur, eds. Pages 45-55 in Aspen: management in the western United States. ecology and U. S. Dep. Agric., For. Servo Gen. Tech. Rep. RM-119. National Oceanic and Atmospheric Administration. 1988. Climatological data, Colorado. U. S. Dep. Comm., Nat1. Oceanic and Atmospheric Admin. 93(13):5, 11. Newton, I. 1979. Population ecology of raptors. Vermillion, S. D. 399 pp. Buteo Books, �__________ , and M. Marquiss. 1982. Food, predation, and breeding season in sparrowhawks (Accipiter nisus). J. Zool., Lond. 197:221-240. Reynolds, R. T. 1972. new hypothesis. 1983. Sexual dimorphism in accipiter hawks: Condor 74:191-197. Management of western coniferous forest habitat for nesting accipiter hawks. Servo Gen. Tech. Rep. RM-107. 1989. a U.S. Dep. Agric., For. 7 pp. The status of accipiter populations in the western United States. Pages 92-101 in B. Pendleton, K. Steenhof, and M. N. Kockert, eds. Proc. western raptor management symposium and workshop. Nat1. Wildl. Fed., Washington, D. C. __________ , and E. C. Mes1ow. 1984. Partitioning of food and niche characteristics of co~xisting Accipiter during breeding. ~ Auk 101:761-779. , E. C. Meslow, and H. M. Wight. 1982. Nesting habitat of coexisting accipiter hawks breeding in Oregon. J. Wildl. Manage. 46:124-138. SAS Institute Inc. Version 6 Ed. Schipper, W. J. A. 1987. SAS/STAT Guide for Personal Computers, SAS Institute Inc., Cary, NC. 1973. 1028 pp. A comparison of prey selection in sympatric harriers Circus in western Europe. Gerfaut 63:17-120. Shepperd, W. D. 1990. A classification of quaking aspen in the central Rocky Mountains based on growth and stand characteristics. West. J. Appl. For. 5:In press. �Snyder, N. F. R., and J. W. Wiley. 1976. in hawks and owls of North America. Sexual size dimorphism Ornitho1. Monogr. 20:96 pp. Steel, R. G. D., and J. H. Torrie. 1980. Principles and procedures of statistics -- a biometric approach. McGraw-Hill, Inc., New York, NY. Storer, R. W. 1966. 633 pp. Sexual dimorphism and food habits of three North American accipiters. Waller, R. A., and D. B. Duncan. Auk 83:423-436. 1969. A Bayes rule for the symmetric multiple comparisons problem. J. Am. Statist. Assoc. 64:1484-1503. Weber, W. A. 1976. Rocky mountain flora. Press, Boulder, CO. 479 pp. Colorado Assoc. Univ. �Chapter 2 NESTING HABITAT OF ACCIPITERS IN SOUTHWEST COLORADO North American accipiters are sympatric throughout much of the western United States (Reynolds et al. 1982; Moore and Henny 1983; Fischer 1986). During the nesting period, northern goshawks (Accipiter genti1is), Cooper's hawks (a. cooperii), and sharp-shinned hawks (a. striatus) exploit different habitats for nesting (Reynolds et a1. 1982, Moore and Henny 1983) and forage for birds and mammals of different sizes and taxa -(Storer 1966, Reynolds and Meslow 1984). In Colorado, accipiters occur on the east and west slopes of the Continental Divide where they nest and forage in mature quaking aspen (Populus tremu1oides) and conifer (abies, Picea, Pseudotsuga) forests. In western North America, accipiter nest-site characteristics have been quantified in conifer-dominated forests (Reynolds et al. 1982, Moore and Henny 1983), but few data exist on nests in or proximate to extensive deciduous stands. Shuster (1980) reported northern goshawks in predominantly pine (Pinus) forests of western Colorado nested in mature aspen trees (n - 10 nests) more often than in lodgepole pine (l. contorta) (n 5 nests) or ponderosa pine (l. ponderosa) (n - 5 nests); however, nest-site characteristics of other accipiters were not investigated. Fischer (1986) examined relative abundance of nesting accipiters in 6 habitat classes [including an aspen-bigtooth maple (Acer �267 grandidentatum) forest class], but did not identify habitat variables associated with nests in aspen forest. Accipiters appear to use foraging habitats opportunistically (Reynolds 1989). Sharp-shinned hawks, the smallest species, should therefore be capable of using a wider range of habitat than goshawks, the largest species. However, accipiters appear to have specific nesting habitat requirements (Reynolds 1983). In Oregon, sharp-shinned hawks nested in young, dense, even-aged conifer forests; Cooper's hawks used older, less dense, even-aged stands; and goshawks used mature to old-growth, multilayered stands (Reynolds et al. 1982). Aspen stands in Colorado comprise over 60% of the 1.78 million ha of commercial aspen areas in the western United States (Green and Van Hooser 1983). Currently, over 70% (1,484 of 2,004 stands surveyed) of Colorado~s aspen trees are in 70-120+ age classes (Shepperd 1990). Proposed aspen management by commercial thinning, clear-cutting, and . removal of conifers to encourage growth of replacement aspen stands (Jones et a1. 1985) emphasizes the need for data on accipiter use of aspen and aspen-associated forests. This study describes the vegetation and topography at accipiter nest sites in mature aspen, mature conifer, and mixed aspen-conifer forest types. Factors responsible for nesting-habitat use are discussed under the assumption that accipiters attempt to maximize nest productivity. are examined. Sharp-shinned hawk nesting chronology and productivity �STUDY AREA The study area included portions of Gunnison and Grand Mesa National forests in Gunnison, Delta, and Mesa counties, Colorado and was bordered on the north by Colorado Highway 65, northwest by Colorado Highway 330 extending east to the border between Pitkin and Gunnison counties, east by the Ruby Range, and south by the southern border of Grand Mesa National Forest. Climax aspen stands and conifer communities occur in these forests between 2,750 and 3,200 m in elevation. Large (> 500 ha) and small (100-200 ha) stands of mature aspen, conifer, and mixed aspen-conifer were searched for accipiter nests. conifer species were subalpine fir (a. lasiocarpa), engelmannii), and blue spruce (E. pungens). Principal Engelmann spruce (E. At lower elevations, forests contained large (100-500 ha) clearings with low shrub, forb, and grass cover. South-facing slopes were dominated by Gambel's oak (Quercus gambelii). Aspen forests were even-aged, single storied, and possessed narrow, dome-like crowns. Stands were relatively open due to sparse canopy cover and an absence of dead branches to within -1 m below the crown. Mixed aspen-conifer forests appeared more dense than pure aspen forests, and often possessed multi-layered canopies. Understory vegetation of both pure and mixed aspen stands was dense. Conifer forests were single- or multi-storied depending on the level of past disturbance (fire, cutting, disease) or deterioration, especially in old-growth (120+ yr) stands. All conifer forests had dense overstories and sparse understories. Understory vegetation types varied depending on elevation, slope, aspect, and forest cover type. Aspen and mixed aspen-conifer �lb9 understories were mostly herbaceous with a minor shrub component. Dominant forbs included butterweed groundsel (Senecio ~), white geranium (Geranium richardsonii) , Barbey larkspur (Delphinium barbeyi), white-flowered peavine (Lathyrus leucanthus), and monkshood (Aconitum co1umbianum). Prominent low-growing plants included elk sedge (Carex geyeri), wild strawberry (Fragaria ovalis), yellow prairie violet (Viola nuttallii), and fringed brome (Bromus ci1iatus). The shrub component consisted primarily of snowberry (Symphoricarpos), chokecherry (Prunus virginiana), and true mountain-mahogany (Cercocarpus montanus). Conifer understories were dominated by low-growing herbs including heart-leafed arnica (Arnica cordifo1ia), field horsetail (Eguisetum arvense), and elk sedge, and low shrubs including myrtle blueberry (Vaccinium myrti11us) and kinnikinnik (Arctostaphylos uva~ursi). Plant names follow Weber (1976). Private lands within the national forests were used primarily for livestock grazing. Sheep and cattle foraged freely in the study area during July and August. Most of the study area had been grazed by the end of the field seasons. METHODS Ground searches for accipiter nests began in May 1988 and 1989, and continued through the breeding season (incubation, nestling, and fledgling stages). Stands with characteristics of accipiter nest sites in western montane forests (Platt 1973, Shuster 1976, Hennessy 1978, Reynolds et al. 1982, Moore and Henny 1983, Fischer 1986) were selectively searched, although "unsuitablen stands were also explored en route to more nsuitablen stands. Stands for intensive search efforts �were selected from aerial photographs (1:24,000) and topographic maps (7.S-min series) and included mature aspen, conifer, and mixed aspen-conifer habitats near ephemeral (drainages, marshes) and permanent (streams, creeks, ponds) sources of water. In addition, known sharp-shinned hawk nest sites occupied in previous years (1 used in 1986, 1 used in 1986 and 1987, and 2 used in 1987) (R. T. Reynolds, U.S. For. Serv., unpubl. data) were examined. Active nest sites were identified by the presence of a nest, breeding pair, and plucking areas with recent signs of activity (e.g., feathers, fur, casts, feces, and molted accipiter. feathers). Nest site is defined as "the area (immediately) surrounding the tree ...used by a nesting pair during an entire nesting season, exclusive of foraging areas" (Reynolds et al. 1982:126). Vegetation and physiographic characteristics of active accipiter nest sites were measured after young dispersed or nests failed. variables measured included: Habitat 1) species, age, height, and diameter at breast height (dbh) of the nest tree; 2) nest-site elevation, aspect, slope, and canopy cover (the latter measured by point-centered quarter method) (Cottam and Curtis 1956); 3) "nest height and directional exposure; 4) distance of nest tree to water; 5) dominant understory vegetation (estimated visually as the species covering the largest proportion of ground); and 6) average stand age. Heights and slopes were measured with a clinometer, aspects and exposures with a compass, dbh with a logger's cm tape, canopy cover with a densiometer, distances with a meter tape, and elevations from topographic maps. Stand age was estimated by coring the nest tree and 3-5 randomly selected overstory trees in the nest site, then counting and averaging the core rings. �· Z /l. Twenty years were added to ring-counts of conifers for tree growth to breast height (Alexander 1974), whereas 0 years were added to aspen ring-counts (Y. D. Shepperd, U.S. For. Serv., unpubl. data). Differences in nest-tree height, dbh, and age, nest-site slope, and nest height between sharp-shinned and Cooper's hawks were tested with Mann-Whitney tests (NPAR1YAY; SAS Inst. Inc. 1987) and evaluated at the a - 0.10 significance level. Rayleigh's R statistic (Zar 1984) was used to test the null hypotheses that accipiter (1) nest-site aspect and (2) nest directional exposure were randomly distributed. were evaluated at the a - 0.05 significance level. Rayleigh's tests All aspects and exposures (0-359°) were assumed to be equally available. In addition, mean directional aspects and exposures and their angular deviations (AD) were determined for each species (Rayleigh's procedure, Zar 1984). Sharp-shinned hawk nests were visited 2-3 times each week and their status recorded until fledglings dispersed. Nesting chronology of goshawks and Cooper's hawks was not monitored. RESULTS Approximately 28,750 ha of national forest lands were searched for nesting accipiters. Teams of 2-4 individuals spent 160, 100, and 100 hours searching for nests in contiguous conifer, aspen, and mixed aspen-conifer stands, respectively. Twenty accipiter nests were found including 7 sharp-shinned hawk, 2 Cooper's hawk, and 1 northern goshawk nest in 1988 and 7 sharp-shinned hawk. 2 Cooper's hawk, and 1 northern goshawk nest in 1989. Of 4 sharp-shinned hawk nest sites used in 1987, 1 (25%) was reused in 1988. Two (29%) of the 7 sharp-shinned hawk nest sites found during 1988 were reused in 1989. At reoccupied sites, all �272 new nests (n - 3) were built < 40 m from former nests. Cooper's hawks did not reuse nest sites from previous years; however, the goshawk site was reoccupied. The 1988 and 1989 goshawk nests were 150 m apart.. Mean clutch size for 6 sharp-shinned hawk nests was 4.7 ± 0.2 (SE) eggs. Hatching occurred between 6 and 13 July in 1988 (n - 4), and on 28 June (n - 1) and between 4-6 July (n - 2) in 1989. nests were found post-hatch. The remaining Assuming a 30-32 day incubation period (Platt 1973, Hennessy 1978, Reynolds and Wight 1978), egg laying was initiated in late May and incubation in early June. Fledging occurred between 28 July and 8 August in 1988 and between 2 and 6 August in 1989. Thus, duration of the nestling period varied between 20 and 33 days. An average of 3 fledglings was observed at nest sites during 1988 (n - 8 nests, SE - 0.2) and 1989 (n - 2 nests, SE - 1). Fledgling dispersal occurred from mid- to late-August during both years. All (n - 7) sharp-shinned hawk nests in 1988 were successful; however, only 2 of 7 nests fledged young during 1989. A female and male disappeared at 2 nests and nestlings at 3 nests were depredated. One Cooper's hawk nest was depredated in 1988; young successfully fledged from the remaining nests (n - 3). Goshawk nests were successful both years. Most (70%) accipiter nests found were in 700-2,000-ha sections of forest separated by 3-6 km of forest containing no nests (Fig. 2.1). Average distance between active nests of sharp-shinned hawks (nearest neighbor) was 2.2 km and ranged from 1.0 to 2.5 km. Two sharp-shinned hawk nests were approximately 0.5 and 1.5 km from active Cooper's hawk nests, and another sharp-shinned hawk nest was within 1.2 km of a �NATIONAL FOREST BOUNDARY \ \/ ./ • ~ ,-.",. / . I J • • GRAND MESA NATIONAL FOREST . Km I I -1 -DENVER I 0 __ 1 /' • GUNNISON NATIONAL F~REST COLORADO, N .. .. .. I .. .' ...... ~i ..____ .. . ... J. ... :. .. .·1 o SSHA 1988 • SSHA 1989 ~COHA 1987 6COHA 1988 ONOGO 1988 .. Fig. 2.1. .. . . .. .NOGO 1989 Relative location of goshawk (NOGO), Cooper's hawk (COHA), and sharp-shinned hawk (SSHA) nests in 1 region of Gunnison and Grand Mesa National forests, Colorado, 1987-89. state map represents the expanded area. Slash marks delineate areas searched. Shaded portion of N .....• w �274 goshawk nest. Nests of goshawks and Cooper's hawks were not found in the same section of forest. Accipiter nest sites ranged from 2,354 (Cooper's hawk) to 2,935 m (goshawk) in elevation and were located 3 (goshawk) to 400 m (sharp-shinned hawk) from water (Table 2.1). All sharp-shinned hawk nests were in small (1-14 ha), insular conifer or mixed aspen-conifer stands surrounded by either aspen forest (10), mixed forests (3), or conifer forests (1). sparse. Understory vegetation at all nest sites was Surrounding forests varied from pure aspen (3) to mixed (1) forests for Cooper's hawk nests, whereas contiguous conifer forests surrounded goshawk nests. Carex, Arnica cordifolia, and species of moss dominated understories at sharp-shinned hawk nests. at goshawk nest sites. Carex was dominant Other prominent species included Vaccinium, Eguisetum, moss, and young 6. lasiocarpa. Dominant understory species were variable at nest sites of Cooper's hawks. Eleven of 14 sharp-shinned hawk nests were in mature (70-120 yr) stands; 1 nest was in an old-growth (120+) stand, and 2 nests were in young (60 yr) stands. Goshawks and Cooper's hawks nested in old-growth abd mature stands, respectively. Nest-site slope gradient did not differ (l - 0.14) between sharp-shinned and Cooper's hawks, but appeared steeper for sharp-shinned hawks than goshawks (Table 2.1). aspect for all species was northerly (n - 20, l ~0.002) (Fig. 2.2). n- & - 11°, AD - 54°; Mean aspects ranged from northwest (311°, 2, AD - 68°) for goshawks to northeast (51°, Cooper's hawks. Nest-site n- 4, AD - 56°) for Site canopy cover was high (~ 94%) for all 3 species. The majority (3 of 4) of Cooper's hawk nests were in aspen trees. Sharp-shinned hawks nested only in conifers (Abies, Picea) and goshawks �275· Table 2.1. Characteristics of accipiter nest sites in southwest Colorado, 1988-89. Accipiter Sharp-shinned hawk (n - 14) Characteristic a Cooper's hawk (n - 4) i SE Goshawk (n - 2) SE SE Nest Site Elevation, m 2,682 55 2,590 80 2,931 5 130 32 157 60 25 4 Slope, % 38 5 21 3 14 4 Stand age, yrs 86 5 84 6 Canopy cover, % 94 2 95 3 Distance to water, m 148 22 95 2 Ne.st Tree Species· AL (9), PE (4), PP (1) AL (1), PT (3) PT Height, m 19 1 23 3 26 0 Dbhb 29 2 36 7 44 4 Age, yrs 93 8 102 7 167 5 Height, m 11 1 16 1 19 o Canopy cover, % 99 1 97 2 94 2 Nest aAL - Abies lasiocarpa, PE - Picea engelmannii, PP - f. pungens, PT - Populus tremuloides; sample sizes are in parentheses. bDiameter of tree measured at breast height. �SHARP-SHIN'NED HAWK. COOPER'S HAWK .•• GOSHAWK. , • ~ ~ ~. I .,:() -, 1.. :::::::: :HHHn: • • • Fig. 2.2. 1988-89. Aspect of sharp-shinned hawk, Cooper's hawk, and goshawk nest sites in southwest Colorado, �'L only in aspen trees. II Nests of Cooper's and sharp-shinned hawks were in i 102 yrs, SE - 7 and n - 11, R - 93 yrs, trees of similar age (n 4, SE - 8, respectively; l 0.47), whereas goshawk nests were in old-growth aspen trees (n - 2, R - 167 yrs, SE - 5). Tree height and dbh were similar between sharp-shinned and Cooper's hawks (l - 0.22 for both tests), and appeared to be somewhat taller and larger for goshawks. Nest height was lower for sharp-shinned than Cooper's hawks (l - 0.06), and appeared to be lower than goshawk nests. On average, nests of goshawks and Cooper's hawks were at 73 and 70% of nest-tree height, respectively; sharp-shinned hawk nests were at 58% of total tree height. Whereas nests of sharp-shinned hawks were within the tree crown, Cooper's hawk nests were generally in the lower portion of the crown, and goshawk nests were below the crown. .Mean accipiter nest exposure in nest trees was southeasterly (n - 20, R- 135°, AD - 55°, l S 0.05) and ranged from 127° (n ~ 14, AD - 47°) for sharp-shinned hawks to 208° (n - 2, AD - 45°) for goshawks (Fig. 2.3). Nest-tree canopy cover did not appear to differ among species. DISCUSSION Despite the greater effort searching for nests in contiguous conifer habitat, more accipiter nests were found within large stands of aspen or aspen-dcmfnared forests. The northern goshawk was the only species that nested within conifer habitat. Small, insular conifer or mixed aspen-conifer stands were important to sharp-shinned hawks, as indicated by their exclusive use of these stands. Nest concealment and protection may have affected sharp-shinned hawk preference for these forests. This accipiter appears less �~- SHARP-SHINNED HAWK ~ I COOPER'S HAWK ~ GOSHAWK. t( \L (ll ~ El1illD ~ ~ Fig. 2.3. Directional exposure Colorado, 1988-89. 0 sharp-shinned (j) _,. hawk, Cooper's hawk, and goshawk nests in �279 effective in defending associated nests against predators. with deep, conical crowns of conifers not provided (Reynolds by the high, relatively 1989). The requirement explain why sharp-shinned conifers. leaf-out Layered Because offers protective open crowns of mature for nest concealment sharp-shinned hawks initiated conceal~ent of nest-building cover aspen trees would also hawks placed their nests within crowns of nest building of aspen trees, conifer or densely-stocked stands provided foliage prior to mixed conifer-aspen activities that pure aspen stands did not. The sharp-shinned or aspen-dominated Scott and Crouch conifer forests composition hawks' preference stands possibly (1988) reported of west-central between habitats to nest within stems from foraging that bird densities Colorado did. Sharp-shinned and Meslow birds occurring western Colorado in surveys) Flack's 1984, Chapter in the upper-most 1). than in other strata Flack (1976) demonstrated (shrub, hole, ground). hawks hawks. that nested of counted Although abundances between aspen contain In this study, the single pair of in conifer habitat consumed more mammals by aspen-dominated (7% of diet). The goshawk, because on that aspen forests (53%; 178 of 338 individuals (28% of diet) than hawks at 5 nests surrounded forests feed primarily forest types, his data showed that aspen canopies ample food for sharp-shinned sharp-shinned but species with the forest canopy (1976) study did not compare nest-guild and conifer in aspen and hawks stratum of mature were more abundant aspen requirements. did not differ, small ~irds. many of which are associated (Reynolds extensive of its larger size and ability nest, may have little need for nest concealment. Rather, to defend prey its �280 detectability and vulnerability, and foraging habitat structure probably affected goshawk nest-site choice and placement within the forest landscape. Goshawks feed largely on vertebrates associated with lower portions of the vegetative column (Reynolds and Meslow 1984). The openness of the conifer understory probably enhanced prey vulnerability and goshawk maneuverability more so than dense herbaceous understory in the aspen forests. Cooper's hawks, intermediate in size between goshawks and sharp-shinned hawks, require more open understories for unrestricted flight than sharp-shinned hawks and perhaps more nest concealment than goshawks. Despite nestling depredation at 1 nest, 75% of Cooper's hawk nests were clearly visible in mature aspen trees. Nest concealment, therefore, may not be as important to Cooper's hawks in southwest Colorado as to Cooper's hawks elsewhere in the U.S. (Reynolds et al. 1982, Moore .and Henny 1983). Nest shading and/or accessibility may be more critical in nest placement (Reynolds et al. 1982, Kennedy 1988). Cooper's hawks' nests in this study were surrounded by mature aspen (3 nests) or mixed aspen and conifer (1 nest) forests. Factors affecting Cooper's hawk nest proximity to mature aspen forests may be similar to those influencing sharp-shinned hawk nest-site choice (e.g., prey composition and foraging success). Overall accipiter nest-site aspect was northerly and nest exposure southeasterly. Reynolds et al. (1982) attributed the tendency of accipiters in Oregon to nest on sites with northerly aspects to a preference for cool, shaded sites. Northerly sites receive less direct sunlight during summer months and thus minimize the possibility of heat stress to nestlings. Northerly sites also experience less moisture loss �281 due to evaporation, southern-exposed exposure which results nests may be a function well as thermoregulation. Branch density side of the trunk, especially densities tree density sites (Reynolds et al. 1982). of accipiter southern in greater provided improved than dryer, The southeasterly of tree conformation tended to be greater in conifers. shade, nest support, Greater and perhaps as on the branch nest concealment. Nest-site goshawks. nested gradient was steep for sharp-shinned Shuster sharp-shinned (1980) also found that goshawks (& - on gentle 12.5%) slopes. hawks appeared power. Apparent in western Slope gradient to be steeper differences at nests of perhaps in nest-site due to lack of slope among species may result from the hawks' prefer.ence for specific are associated Distance to watEr varied greatly among species, was higher required Previous observed from the greater availability trees than Cooper's to support investigators that nest-site different that Finally, water Nest-site or Cooper's hawks, of old-growth goshawks or sharp-shinned appeared to use hawks, which were their large nests. (Reynolds et al. 1982, Moore and Henny characteristics forest successional among stands used by accipiters with young although for nesting. than sharp-shinned stands at higher elevations. larger-diameter pr?bably to all accipiters for goshawks and may have resulted conifer habitats with slope rather than choice of slope directly. seemed to be important elevation Colorado than at nests of Cooper's hawks, but they·did not differ statistically, statistical hawks and gentle for stages. of accipiters Associated [sharp-shinned (40-60 yr) stands, Cooper's corresponded 1983) to with age differences hawks were identified hawks with older (50-80 yr) �stands, and goshawks with mature (80+ yr) stands] were structural differences among nest sites. Conclusions about habitat partitioning among Colorado accipiters are speCUlative due to the small number of nests found. However, habitat partitioning among Colorado birds appears to be related less to stand age differences (particularly between Cooper's and sharp-shinned hawks), and more to structural differences, among forest stands. Sharp-shinned hawks require dense stands of conifers; Cooper's hawks use less dense stands of aspen or mixed aspen-conifer cover types; and goshawks use relatively open coniferous forests interspersed· with large aspen trees. In southwest Colorado, the apparent absence of habitat partitioning on tree age was perhaps due to a dearth of younger-aged stands. Aspen-associated forests also may exhibit less stand-age variability than pine- and fir-dominated forests surveyed in previous studies .. ~AGEMENT IMPLICATIONS Few studies of nesting accipiters (but see Shuster 1976, 1980) have focused on use of aspen forests. Aspen management, primarily clear-cutting, has been proposed for much of Colorado's aspen timberland and emphasizes the need for information on accipiterfhabitat relationships. The data suggest that sharp-shinned hawks are vulnerable to predation and require protective cover provided by conifers at the nest. Foraging success in surrounding aspen habitats may also influence nest-site location for this species. Whereas northern goshawks appear to require relatively open, old-growth coniferous forests for foraging, as well as large aspen trees for nesting, Cooper's hawks primarily use aspen-dominated habitats for foraging and nesting. �283 Because accipiters require specific stand characteristics for nesting (Reynolds 1983), active and potential nest sites should not be modified by timber harvests. Tree cutting or thinning would alter stand structure and vegetative composition, and perhaps make nest sites unsuitable for accipiters. Alternatively, because accipiters use forested lands opportunistically for foraging (Reynolds 1989), and include fragmented (whether natural or man-made) as well as continuous forests within their home ranges (Reynolds 1983), limited timber management may occur in habitats used for foraging, but only in years during which forests are not used by accipiters. Guidelines for aspen management should be developed on based recommendations obtained from this and future studies on accipiter use of these forests. LITERATURE CITED Alexander, R. A. 1974. Silviculture of subalpine forests in the central and southern Rocky llountains: the status of our knowledge. u.S. Dep. Agric., For. Servo Res. Paper RM-121. 88 pp. Cottam, G., and J. T. Curtis. 1956. in phytosociological sampling. Fischer, D. L. 1986. hawks in Utah. Provo, UT. Flack, J. A. The use of distance measure Ecology 37:451-460. Foraging and nesting habitat of Accipiter Ph.D. dissertation, Brigham Young Univ. , 33 pp. 1976. North America. Bird populations of aspen forests in western Ornithol. Monogr. 19. 97 pp. �Green, A. W., and D. D. Van Hooser. the Rocky Mountain states. Resour. Bull. INT-33. Hennessy, S. P. 1978. 1983. Forest resources of U. S. Dep. Agric., For. Servo 127 pp. Ecological relationships of accipiters in northern Utah -- with special emphasis on the effects of human disturbance. M.S. thesis, Utah State Univ., Logan. 66 pp. Jones, R. J., R. P. Winokur, and W. D. Shepperd. Management overview. P. Winokur, eds. Pages 193-195 in N. V. DeByle and R. Aspen: western United States. 1985. ecology and management in the U. S. Dep. Agric., For. Servo Gen. Tech. Rep. RM-119. Kennedy, P. L. 1988. Habitat characteristics of Cooper's hawks and northern goshawks nesting in New Mexico. in Pages 218-227 R. L. Glinski, B. G. Pendleton, M. B. Moss, M. N. LeFranc, Jr., B. A. Millsap, and S. W. Hoffman, eds. southwest raptor management symposium and workshop. Proc. Natl. Wildl. Fed., Washington, D. C. M oore, K . R ., an d C ..J Henny . 1983 . Nest site characteristics of three coexisting accipiter hawks in northeastern Oregon. Raptor Res. 17:65-76. Pl at,t J .'B 1973 . Habitat and time utilization of a pair of nesting sharp-shinned hawks (Accipiter striatus velox). M. S. thesis, Brigham Young Univ., Provo, UTe 41 pp. R eyno lds , R . T . 1983. Management of western coniferous forest habitat for nesting accipiter hawks. Servo Gen. Tech. Rep. RM-107. 7 pp. U.s. Dep. Agric., For. �285 1989. The status of accipiter populations in the western United States. Pages 92-101 in B. Pendleton, K. Steenhof, and M. N. Kockert, eds. Proc. western raptor management symposium and workshop. Natl. Wildl. Fed., Washington, D. C. __________________ , and E. C. Meslow. 1984. Partitioning of food and niche characteristics of coexisting Accipiter during breeding. Auk 101:761-779. and H. M. Wight. 1978. Distribution, density, and productivity of accipiter hawks breeding in Oregon. Bull. Wilson 90:182-196. _______________ , E. C. Mes1ow, and H. M. Wight. 1982. Nesting habitat of coexisting accipiter hawks breeding in Oregon. J. Wildl. Manage. 46:124-138. SAS Institute Inc. 1987. Version 6 Ed. SAS/STAT Guide for Personal Computers. SAS Instit~te Inc., Cary, NC. Scott, V. E., and G. L. Crouch. 1988. 1028 pp. Summer birds aridmammals of aspen-conifer forests in west-central Colorado. Dep. Agric., For. Servo Res. Paper. Shepperd, W. D. 1990. RM-280. U.S. 6 pp. A classification of quakirigaspen in the central Rocky Mountains based on growth and stand characteristics. Shuster, W. C. 1976. montane Colorado. 1980. West. J. Appl. For. S:In press. Northern goshawk nesting densities in West. Birds 7:108-110. Northern goshawk nest site requirements in the Colorado Rockies. West. Birds 11:89-96. �1989. The status of accipiter populations in the western United States. Pages 92-101 in B. Pendleton, K. Steenhof, and M. N. Kockert, eds. Proc. western raptor management symposium and workshop. Nat1. Wi1dl. Fed., Washington, D. C. _________________ , and E. C. Meslow. 1984. Partitioning of food and niche characteristics of coexisting Accipiter during breeding. Auk 101:761-779. and H. M. Wight. 1978. Distribution, density, and productivity of accipiter hawks breeding in Oregon. Bull. Wilson 90:182-196. _________________ , E. C. Meslow, and H. M. Wight. 1982. Nesting habitat of coexisting accipiter hawks breeding in Oregon. J. Wildl. Manage. 46:124-138. SAS Institute Inc. 1987. Version 6 Ed. SAS/STAT Guide for Personal Computers. SAS Instit~te Inc., Cary, NC. Scott, V. E., and G. L. Crouch. 1988. 1028 pp. Summer birds aridmammals of aspen-conifer forests in west-central Colorado. Dep. Agric., For. Servo Res. Paper. Shepperd, W. D. 1990. RM-280. U.S. 6 pp. A classification of quakirigaspen in the central Rocky Mountains based on growth and stand characteristics. Shuster, W. C. 1976. montane Colorado. 1980. West. J. App1. For. 5:In press. Northerrigoshawk nesting densities in West. Birds 7:108-110. Northern goshawk nest site requirements in the Colorado Rockies. West. Birds 11:89-96. �Storer, R. W. 1966. Sexual dimorphism and food habits of three North American accipiters. Weber, W. A. 1976. Rocky mountain flora. Press, Boulder, CO. Zar, J. H. 1984. Auk 83:423-436. 479 pp. Biostatistical analysis. Englewood Cliffs, NJ. Colo. Assoc. Univ. 718 pp. Prentice-Hall, Inc., �APPENDICES • �APPENDIX 1. Prey species at 11 sharp-shinned hawk nest sites in southwest Colorado during 1988-89 breeding seasons. Common names are in parentheses. Adult Foraging weighta•b Prey Actitis macularia (spotted sandpiper) Selasphorus platycercus (broad-tailed hummingbird) Sphyrapicus nuchalis (red-naped sapsucker) Picoides pubescens (downy woodpecker) g. villosus (hairy woodpecker) Picoides spp. (woodpecker) Contopus sordidulus (western wood-pewee) Empidonax hammondii (Hammond's flycatcher) E. oberholseri (dusky flycatcher) E. difficilis (western flycatcher) ·Empidonax spp. (flycatcher) Progne subll (purple martin) Tachycineta bicolor (tree swallow) I. thalassina (violet-green swallow) Parus atricapillus (black-capped chickadee) g. gambeli (mountain chickadee) Parus spp. (chickadee) Sitta canadensis (red-breasted nuthatch) Certhia americana (brown creeper) Salpinctes obsoletus (rock wren) Troglodytes aedon (house wren) Regulus satrapa (golden-crowned kinglet) zcne" (g) Adult (n) Prey age SubadultC Nestlingd (n) 1 40.4 2 2 3.6 1 3 50.3 3 3 27.0 6 3 66.3 2 3 46.7 1 3 12.8 13 3 10.1 10 3 10.4 6 3 10.9 4 2 3 10.3! 2 1 4 49.4 1 4 20.1 16 4 14.2 8 3 1 (l)g 2 -10.8 5 9 (3) 2 10.8 9 18 (2) 2 10.8 2 3 9.8 1 3 8.4 3 1 .16.5 1 1 10.9 23 3 6.2 3 1 5 (n) �APPENDIX 1. Continued. Prey R. calendula (ruby-crowned kinglet) Regulus spp. (kinglet) Sia1a mexicana (western bluebird) ~. curro ides (mountain bluebird) M~adestes townsendii .(Townsend's solitaire) Catharus ustulatus (Swainson's thrush) g,yttatus (hermit thrush) Catharus spp. (thrush) Turdus migratorius (American Robin) Dumate11a caro1inensis (gray catbird) Vireo solitarius (solitary vireo) y. gilvus (warbling vireo) y. olivaceus (red-eyed vireo) ~spp. (vireo) Vermivora celata (orange-crowned warbler) Dendroica petechia (yellow warbler) Q. coronata (yellow-rumped warbler) Dendroica spp. (warbler) Oporornis to1miei (MacGillivray's warbler) Yi1sonia pusi11a (Yilson's warbler) Piranga ludoviciana (western tanager) Pipilo chlorurus (green-tailed towhee) Aimophila spp. (sparrow) ~. Adult Foraging weight zone (g) Adult (n) Pre~ age Subadult Nestling .(n) (n) 6 (1) 3 6.7 11 3 6.4 2 5 28.1 2 5 29.6 1 5 34.0 1 1 30.8 1 1 31.0 10 1 30.9 5 5 77 .3 27 2 36.9 1 2 16.6 6 2 12.0 14 2 16.7 2 15.1 1 2 9.0 2 2 9.8d'd' 3 9.2~~ 12.1 3 10.8 1 1 10.4 5 2 6.9 8 3 28.1 6 5 2 29.4 5 1 1 19.7 1 1 2 4 (8) 2 15 (9) 14 (3) 1 2 (1) 7 3 39 4 1 38 (1) 1 �APPENDIX 1. Continued. Prey Adult Foraging weight zone (g) Sgizella arborea (American tree sparrow) .§.. gasserina (chipping sparrow) Pooecetes gramineus (vesper sparrow) Passerculus sandwichensis (savannah sparrow) Melospiza melodia (song sparrow) t1. lincolnii (Lincoln's sparrow) Zonotrichia leucophrys (white-crowned sparrow) Junco hyemalis (dark-eyed junco) Unknown juvenile sparrow Agelaius phoeniceus (red-winged blackbird) Molothrus ater (brown-headed cowbird) Pinico1a enucleator (pine grosbeak) Carpodacus cassinii (Cassin's finch) s:!. mexicanus (house finch) Cardue1is pinus (pine siskin) Coccothraustes vesgertinus (evening grosbeak) Unknown juvenile bird Sorex montico1us (montane shrew) Tamias minimus (least chipmunk) Tamaisciurus hudsonicus (Pine squirrel) Thomomys talpoides (northern pocket gopher) Peromyscus maniculatus (deer mouse) C1ethrionom;:!sgapgeri (Gapper's red-backed vole) Adult (n) Pre;:!age Subadult Nestling (n) (n) (1) 2 20.1 5 12.3 1 25.7 1 20.1 6 2 20.8 5 2 17.4 26 1 1 25.5 35 6 (3) 5 19.6 25 12 (4) 2 21.1 2 1 41.5 (1) 2 49.0rU 1 3 38.8~~ 56.4 8 1 3 26.5 2 3 21.4 2 5 14.6 10 3 59.4 1 1 1 1 (1) 22.1 1 1 (2) 1 10 2 1 6.8h 2 5 46.1 3 5 225.3 2 1 94.61 7 1 24.6 1 1 26.8 17 4 �APPENDIX 1. Continued. Prey Phenacom::lsintermedius (heather vole) Microtus montanus (montane vole) M. longicaudus (long-tailed vole) Microtus spp. (vole) Zapus princeps .(western jumping mouse) Unknown mouse Adult Foraging weight zone (g) Adult (n) 1 36.8 3 1 45.3 2 1 46.8 5 1 46~1 10 1 23.8 7 1 24.2 1 Pre::la~e Subadult Nestling (n) (n) -Bird weights are from Dunning (1984) and mammal weights are from Armstrong (1972) unless otherwise specified. bSubadults with unsheathed remiges and partly sheathed retrices were assigned the adult weight; subadults with partly sheathed remiges and retrices were assigned 3/4 (adult weight); nestlings received 1/2 (adult weight). CBirds with partially sheathed feathers. dBirds with fully sheathed retrices and remiges . •(1) ground-shrub; (2) shrub-canopy; (3) canopy; (4) aerial; (5) generalist. fWeight - 1/2(E. hammondii weight + E. oberholseri weight) &Numbers in parentheses are subadults with unsheathed remiges (adult weight). hHall (1946). iU.S. Fish and Wildlife Service museum specime~ labels, Fort Collins, CO. �APPENDIX 2. Size and taxonomic classification of prey used in preference analyses. Familyb Size class (.g). Avian prey Mammalian prey Avian prey Mammalian prey 3.4-8.0 (1) 3.4-8.0 (1) Picidae Sorcidae 8.0-15.6 (2) 15.6-27.0 (3) Tyrannidae Sciuridae 15.6-27.0 (3) 27.0-42.9 (4) Hirundinidae Geomyidae 27.0-42.9 (4) 42.9-64.0 (5) Paridae Muridae 42.9-64.0 (5) 91.1-125.0 (7) Sittidae/Certhiidae Dipodidae 64.0-91.1 (6) 125.0-166.0 (8) Trog1odytidae Muscicapidae Vireonidae Emberizidae Fringillidae ·Size classes according to Storer (1966). Size classes of mammals not found in remains nor counted during surveys were excluded. bFami1y names follow Banks et al. 1987. Prepared-by Approved by �JOB PROGRESS REPORT State of: Project: Colorado W-152-R Upland Bird Research Work Plan: 21 Job Title: Evaluation of Habitat Quality on Conservation Reserve Lands in Eastern Colorado Period Covered: Author: Job 5 _ 01 January through 31 December 1990 Warren D. Snyder Personnel: David C. Wilson and Warren D. Snyder, Colorado Division of Wildlife ABSTRACT Visual obstruction readings (VQR) , the primary index to grass-forb quality for wildlife, were 0.47 in early spring 1990 and 0.83 dm in mid summer within 140 Conservation Reserve Program (CRP) fields sampled in eastern Colorado. This overall sample included 105 fields randomly selected for.sampling in 1988. Early spring VOR indices averaged 0.39 dm contrasted to 0.67 dm in mid summer for this group (including 7 fields cost shared by the Division of Wildlife). These 7 fields, combined with 35 additional fields cost-shared by the Division of Wildlife, yielded average VQR indices of 0.66 dm (early spring) and 1.09 dm (summer). F.ields containing switchgrass (Panicum virgatum), grass-alfalfa, and grass-sweet clover mixtures had the highest summer VQR indices. Precipitation stimulated early spring and late summer vegetation growth, however, June was extremely hot and dry. Canopy cover averaged 52.3% in spring and 54.2% in summer 1990 of which seeded perennials respectively comprised 40 and 51%. A relationship between percent land in the CRP and ring-necked pheasant (Phasianus colchicus) crowing count indices could not be detected in spring 1990. �EVALUATION OF HABITAT QUALITY ON CONSERVATION RESERVE LANDS IN EASTERN COLORADO Warren D. Snyder INTRODUCTION Data collection continued for the third year as part of an ongoing study evaluating vegetation quality on Conservation Reserve Program (CRP) fields in eastern Colorado. Two data sets were under assessment. The first was a random sample of 105 fields for which data were supplied to the u.S. Fish and Wildlife Service, National Ecology Center (NEC) at Fort Collins. Seven of those fields were included within a second data set of 42 CRP fields which the Division of Wildlife cost shared to obtain better cover quality. This is the second year of evaluation of CDOW cost-shared fields. P. N. OBJECTIVES Determine distribution and quantity of Conservation Reserve Program land in eastern Colorado in relation to distribution of selected wildlife species, evaluate the quality of vegetation on these lands for selected wildlife species, measure response of selected wildlife species to the Conservation Reserve Program using existing annual surveys, and evaluate the impact of the Colorado Division of Wildlife's cost-share program on cover quality. SEGMENT OBJECTIVES 1. Conduct evaluations of randomly selected CRP fields within eastern Colorado as part of a regional and national assessment of the Conservation Reserve Program coordinated by the National Ecology Center (NEC) of the U.S. Fish and Wildlife Service. 2 .. Conduct intensive visual obstruction readings (VOR).in a stratified random sample of CRP fields and proximal controls; 3. Conduct intensive visual obstruction readings (VOR) in a sample of fields cost shared by the CDOW (for enhancement of cover quality) for comparison with CRP'fields not cost-shared. 4. Estimate response of selected wildlife species to the CRP based on annual population surveys. 5. Compile and analyze data and prepare the annual progress report. METHODS Methods used were described by Snyder (1989 and 1990). Visual obstruction readings were based on the Kirsch method of sampling rather than the procedure required by NEC personnel. However, data supplied to the NEC were converted to their index procedure. �L~O RESULTS AND DISCUSSION Environmental Conditions Precipitation averaged among 9 eastern Colorado weather stations through the first 4 months of 1990 was greater than that received during the same interval in 1989 (Tables 1, 2). Growth of cool-season grasses responded favorably (Table 3). May precipitation was near average, however, June was extremely hot and dry throughout eastern Colorado (Table 2). Above average rainfall was received in July. Increased precipitation continued through fall and early winter 1990 when compared to 1989. Extreme southeastern Colorado (represented by Springfield) consistently received above average precipitation in recent years and more moisture than most other eastern Colorado areas in 1988, 1989, and 1990 (Table 1). However, rainfall was more evenly ·distributed through eastern Colorado in 1990 except for Greeley. Although numerous fields had been mowed or sprayed during summer 1989 (23X), such efforts decreased in 1990 primarily because of advanced grass establishment. Herbicide treatments occurred in late June and July on several fields (16, llX) primarily in Baca County although most fields contained good stands of sideoats g~ama (Bouteloua curtipendu1a) and/or other species. One field in Prowers County was severely hailed in mid-June, 1 field in Pueblo County was redrilled, and a field in Yuma County was disked, apparently for replanting. Observations subsequent to the summer survey revealed that several fields, dominated by annual weeds, were mowed in mid to late summer 1990. Table 1. Annual precipitation eastern Colorado, 1987-90. (in.) at 9 U.S. Weather Bureau locations in Long.:.term Location Springfield Lamar Rocky Ford Limon Burlington Akron Greeley Holyoke Sterling Combined average ~ 16.65 15.40 12.50 15.09 17.41 .17.34 12.45 17.61 14.96 15.49 1987 1988 1989 1990 21.84 15.10 11.51 19.84. 18.22· 19.85 .15.00 20.06 14.92 17.43 11.58 9.42 14.53 13.'10 16.24 12.34 16.45 14.69 18.12 13.45 9.60 11. 71 16.23 13.55 15.71 16.76 13.57 18.75 15.71 17.87 19.60 16.10 20.88 13.70 16.41 18.28 17.37 13.98 14.30 17 .. 48 c ~. \ \ �Table 2. 1990. Monthly and annual precipitation (in.) at 9 U. Springfield Lamar Rocky Ford Limon Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1.32 1.38 0.65 1.10 1.93 0.54 5.58 1.57 2.67 0.44 1.16 0.41 1.00 1.87 0.73 0.92 2.11 2.47 2.30 0.64 2.12 0.23 0.80 0.52 0.80 0.79 0.96 0.28 3.63 0.38 4.91 1.22 2.37 1.07 1.07 0.39 1.04 0.42 1.50 2.19 1.91 0.90 4.34 3.00 2.15 1.14 0.96 0.05 1990 1989 1988 18.75 18.12 17.43 15.71 13.45 11.58 17.87 9.60 9.42 Longterm .! 16.65 15.40 12.50 Month s. Weather Burlington Bureau locations in Eastern Colorado, Akron Greeley 1.01 0.51 1.74 0.77 3.88 1.18 2.53 1.54 1.18 0.81 0.95 0.00 0.75 0.17 1.70 1.50 4.09 0.93 4.71 4.41 0.70 1.06 0.78 0.08 0.96 0.36 4.13 0.94 1.38 0.21 1.14 1".46 1.37 0.45 1.04 0.26 19.60 11.71 14.53 16.10 16.23 13.10 20.88 13.55 16.24 15.09 17.41 17.34 Holyoke Sterling 1.38 0.04 1.11 1.61 2.94 0.36 4.21 1.42 0.86 0.96 1.39 0.13 0.09 0.05 2.40 1.55 1.86 0.92 4.69 3.47 0.99 1.04 1.13 0.09 13.70 15.71 12.34 16.41 16.76 16.45 18.28 13.57 14.69 12.45 17.61 14.96 Table 3. Average visual obstruction readings (dm) within Conservation Reserve fields sampled during pre-greenup and nesting season intervals, eastern Colorado 1988-90. Pre-greenup Nesting Fields Within the NEC Sample 1988 1989 1990 Fields Within the cnaw 1989 1990 as even of 42 cnaw 0.39 0.34 0.39 0.20 0.56 0.67 0.51 0.66 1.13 1.09 Cost Sharea fields were included within the NEC sample. �Evaluation of Conservation Reserve Vegetation Quality Pre-greenup sampling in March 1990 yielded an average VOR of 0.39 dm; similar to early spring indices of previous years (Table 3). Among NEC samples, highest 1990 indices were obtained within the eastern tier of strata (Table 4, Fig. 1). Within stratum 4, 3 CDOW cost-share fields, which contained good cover, increased the average there. In spring 1990, fewer fields (63 vs. 89) were ranked as very poor «0.26 dm) compared to 1989 (Table 5). However, poor to very poor VOR categories «0.51 dm) still dominated (72%) the total sample. By summer (late Jun - early Jul) , VOR indices had increased to 0.67 dm among 105 NEC fields and 1.09 dm among 42 CDOW fields (Table 4), and were above indices from previous years (Table 3). Among all fields, 58 were rated very poor to poor «0.51 dm), 45 were fair (0.51-1.0 dm), and 37 were good to excellent in summer 1990 with respect to quality for pheasant nesting (Table 5). However, about 56% of the fields were in locations where pheasants were either absent or existed only in remnant numbers. Summer VOR's markedly improved over previous years. Summer VOR indices averaged higher in the eastern 3 strata as they had during pre-greenup sampling (Table 4, Fig. 1). VOR indices within Division cost-shared fields averaged >60% higher than fields that were not cost shared (Table 4). Cost-shared fields averaged 0.66 dm in early spring, or fair for pheasant nesting, and 1.09 dm in summer, or good for pheasant nesting. This was partially because most CDOW fields.were in the eastern tier of strata where growing condd t Lons were usually better. Many of the cost-shared fields also contained switchgrass and other grasses that possessed better growth characteristics. Several CDOW fields continued to possess poor to very poor cover through summer 1990. The pre-greenup VOR of cost-shared fields increased from 1989 to 1990 (Table 3). However, there was no marked difference between 1989 and 1990 samples during the summer nesting season. Paired comparison of cost-shared fields with nearby NEC sample fields indicated the cost-shared fields contained higher VOR indices '(f> 0.025, ~ - 2.77, df - 39). Conservation Reserve fields dominated by switchgrass continued, as in 1989, to possess' the highest VOR indices during early summer (Table 6). Fields containing alfalfa also possessed above average VOR indices, although the sample size was low and most possessed poor stands of grass (herbicides could not be used in establishment). Fields with no significant grass varied draJIlat.ically in cover quality from tall weeds to sparse stands of annual gxaases;: thu~:,the rang~:of VOR indices was also wide~ .However,' on average these fields (45) provided above average cover ·quality (Table ,6).' Sandour (Cenchrus spp.), an annual grass ,that was prevalent-in previous years, decreased markedly by 1990. Several fields of smooth brome (Bromus'inermis) were reseeded in spring 1989 (after previously being impacted by Glean herbicide) and the others were younger than average yielding more vigorous growth. In addition, favorable late winter and early spring precipitation stimulated growth of this cool season species, which was primarily planted in stratum 1. Several stands, classed as warm-season mixes, contained considerable sideoats grama and several were in areas marginal for farming in eastern Pueblo and Crowley counties. These factors reduced their average VOR �WI!! L D s ... • LAS ANIMAS ~.~.- . • .1_ -: .•~.L. :__ -,-, .. 1 Stratification Fig. 1. eastern Colorado. .... for random sampling ~ _ conservation Reserve fields in �jUU Visual obstruction readings (dm) within Conservation Reserve fields Table 4. in eastern Colorado during early spring and mid-summer, 1990. - N Stratum fields S12ring 1990 Sum Mean Summer 1990 Sum Mean INITIAL NEC RANDOM SAMPLE 1 2 3 4 5 6 Total 17 11 24 14 278 128 105a 7.192 6.678 9.841 4.091 10.501 1.903 40.206 0.423 0.607 0.410 0.292 0.404 0.190 12.817 8.766 14.795 7.855 18;504 7.329 0.754 0.797 0.616 0.561 0.685 0.611 0.394 70.066 0.667 CDOY COST-SHARED FIELDS ADDED IN 1989 35 24.626 0.704 40.671 l.162 25.269 18.644 28.122 13.093 23.017 8.592 0.972 0.888 1.004 0.727 0.719 0.573 116.737 0.834 65.176 45.661 0.664 1.087 COMBINED NEC AND COST-SHARED SAMPLES 1 2 3 4 5 6 Total 26 21 28 18 328 15a 13.850 12.993 12.754 9.004 13.052 3.179 0.5_33 0.619 0.456 0.500 0.421 0.245 1408 64.832 0.473 COMPARISON OF NON-COST SHARED AND COST SHARED FIELDS NEC CDOY·· 98a 42b .. 37.205 27.627 0.392 0.658 aOne field in stratum 5 and 2 fields within stratum 6 were omitted during spring 1990 samples reducing the NEC total to 102 and the combined total to 137. bInc1udes 7 CDOY fields sampled within the total 105 field NEG sample. �Ranking of Conservation Reserve fields for nesting pheasants by VOR Table 5. classification (Kirsch-dm) during pre-greenup and nesting intervals, eastern Colorado, 1988-90. N Sample <0.26 0.26-0.50 fields 0.51-1.0 1.1-2.0 >2.0 Totals Pre-greenup NEC-1988 NEC-1989 NEC-1990 All 89 fields All 90 fields 76 69 50 89 63 10 18 27 23 35 7 10 17 13 22 5 5 6 11 12 6 2 2 3 5 104 104 102 139 137 87 42 28 46 33 8 26 22 34 25 4 20 35 27 45 3 12 17 20 29 2 5 3 12 8 104 105 105 140 140 Nesting Season NEC-1988 NEC-1989 NEC-1990 All 89 fields All 90 fields Table 6. Visual obstruction readings (dm) in relation to dominant grass species within Conservation Reserve fields in summer 1990, eastern Colorado. Dominant species/cover SwitchgrassAlfalfa-grass inixes· Sweet clover-grass mixes No significant perennial grass Smooth br ome" Warm-season grass mixes Sideoats grama dominantb Wheatgrasses Fields 8 5 5 45 8 11 2826 ~ VOR 2.14 1. 70 1.41 0.95 0.80 0.77 0.69 0.52 aMost fields of smooth brome were planted more recently than others. bMany stands contained considerable blue grama and western wheatgrass. �302 quality. Stands dominated by sideoats grama, primarily in southeastern Colorado, often contained considerable blue grama (Bouteloua gracilis) and western wheatgrass (Agropyron smithii). Stand establishment there was above average because of favorable precipitation (Table 1) and earlier sign-up in ~he CRP resulting in earlier seeding. Wheatgrasses (Agropyron spp.) dominated in stratum 6, and several fields contained dense wheatgrass monocultures, usually with low VOR indices. Percent canopy cover of pere~nial grass increased from 1989 to 1990 during pre-greenup and early summer nesting intervals (Table 7). Percent annual vegetation remained nearly the same, ranging between 25 and 30%. Total canopy cover increased, in part because CRP fields contained more perennial vegetation. However, favorable moisture conditions and anticipated increases with time were also factors. Height remained nearly the same although increases from pre-greenup to summer 1990 were noted. Favorable spring moisture for growth and decreased mowing may have been factors. Both total canopy cover and height tended to be greater in the eastern tier of stra~a (Table 8). Among the 105 NEC fields, 59% contained >25% perennial grass canopy cover in summer 1990 and only 18% contai~ed ~5% (Table 9). Among the additional 35 CDOW fields, 37% contained >25% perennial grass. Winter cover on CRP fields, rated for its over-winter 1989-90 value for pheasants, was predominately poor quality. Among the 140 field sample, over 74% were rated poor, 13% were fair, and <9% were good to excellent. Anticipated quality during winter 1990-91 was estimated during summer sampling and showed similar results. However, some fields containing tall annuals, were mowed subsequent to sampling. Total NEC and additional cost-shared fields were compared with those within pheasant range (Table 10). Winter cover conditions during 1989-90 and 1990-91 were rated little better within pheasant range than within total samples. A higher proportion of the CRP fields within pheasant range contained food within 0.25 mile and were associated with good wintering sites «2 miles) (Table 10). A higher percentage of the fields within pheasant range also contained or were associated with pheasant brood habitat. Table 7. Canopy cover (%) of total vegetation, perennial grass, and annual vegetation, and mean vegetation height (em) within Conservation Reserve fields during pre-g~eenu~ and nesting intervals in 1989 and 1990, eastern Colorado. Pre-greenup Nesting Variable 1989 1990 1989 1990 Perennial grass Annual vegetation Total canopy cover Vegetation height 8.7 28.6 37.3 17.7 20.8 31.5 52.3 16.4 14.5 28.1 42.6 16.3 27.8 26.4 54.2 19.7 �Table 8. Canopy cover (%) of total vegetation, perennial grasses, annual vegetation, and mean vegetation height (cm) within Conservation Reserve fields among strata during pre-greenup and nesting season intervals, eastern Colorado 1990. fields 26 21 28 18 31 13 63.0 57.2 50.7 50.6 45.4 45.2 22.6 17.8 19.3 24.6 19.1 24.6 40.5 39.5 31.4 26.1 26.3 20.6 18.3 17.3 17.6 17.3 13.6 13.7 137 52.3 20.8 31.5 16.4 61.1 53.5 57.3 . 59.8 50.4 39.0 34.4 24.2 25.8 33.5 25.8 22.3 26.7 29.4 31.5 26.3 24.5 16.7 25.0 22.2 16.9 16.7 17.7 20.4 54.2 27.8 26.4 19.7 within NEC and CDOW N Stratum CanoI!~ cover Perennial Annual vegetation grass Total vege.tation Height Pre-greenuI! 1 2 3 4 5 6 Total/mean _-. --. .. Nesting 1 2 3 4 5 6 Total/mean 26 21 213 18 32 15 140 Table 9. Ranking of perennial grass stand establishment fields in eastern Colorado, summer 1990. Percent Variable <5.1 5.1-25 CanoI!~ Cover 25.1-50 >50 NEC SamI!1e 19 18.1 Additional CDOW Cost-share 5 14.3 24 22.9 40.0 42 17 48.6 17.1 20 19.0 SamI!le 6 7 20.0 �Table 10. Conditions on, and associated with, CRP fields rated for pheasants, eastern Colorado, 1990. Variable Sample size, fields Total NEC 105 Percent of CRP Fields within NEC within Additional CDOW within pheasant CDOW pheasant range cost share range 76 35 33 Winter Cover Conditions 1989-90 cover on CRP Poor Fair Good Excellent 80.0 15.2 2.9 1.9 77 .6 15.8 3.9 2.6 57.1 22.9 17.1 2.9 54.5 24.2 18.2 3.0 1990-91 cover on CRP Poor Fair Good Excellent 76.2 20.0 3.8 0.0 72.4 25.0 2.6 0.0 54.3 28.6 14.3 2.9 54.5 27.3 15.2 3.0 Food <0.25 mL 58.1 72.4 80.0 84.8 Good wintering area within 2 mi. 46.7 63.2 54.3 54.4 46.7 78.1 53.9 88.2 91.4 97.1 87.9 97.0 Summer Brood Conditions Brood cover on CRP Brood cover <0.5 mi. Wheat Stubble, Green Wheat and CRP Comparisons Drought conditions during early spring 1989 severely stunted the growth of green wheat throughout eastern Colorado so that residual stubble, left standing over winter (primarily in northeastern Colorado), was also of poor quality. The average VOR of standing wheat stubble in spring 1990 was 0.30 dm; much less than the 0.47 dm average for CRP vegetation during the pregreenup interval (Table 11). In 1988 wheat stubble VOR was 0.40 versus 0.39 dm for CRP. In 1989 wheat stubble VOR averaged 0.62 dm whereas that of CRP was 0.36. The VOR was only 0.13 dm for wheat stubble that was undercut or mulched with a sweep plow (similar to that of previous years). �Table 11. Respective comparisons (VOR) of wheat stubble and green wheat with CRP among strata during pre-greenup and summer intervals in 1990, eastern Colorado. Stratum 1 1 3 & 4 5 6 Average Pre-greenuJ;! Wheat stubble CRP Summer nesting Green wheat CRP 0.39 0.30 0.21 0.22 ·0.28 0.53 0.62 0.47 0.42 0.25 6.63 5.16 4.64 5.34 5.64 0.97 0.79 0.90 0.72 0.57 0.30 0.47 5.40 0.83 Wheat stubble fields were not secure nesting cover because nearly all were tilled between late April and early June. In 1990, 28% of the stubble had been tilled by 4 May, 52% by 15 May, 79% by 25 May and 94% by 8 June. This progression is about average for northeastern Colorado where the survey was taken (Snyder 1984). The VOR index of green wheat was several times greater than CRP during the early summer pre-harvest nesting interval (Table 11). However, VOR indices greater than 2 - 3 dm probably were of little additional value to nesting pheasants and other wildlife .. Taller covers usually were more open near the ground, and therefore, less attractive to ground-nesting avifauna. Green wheat often grows rapidly to become availab~e for nesting in early May. During spring 1990 in northeastern Colorado, the VOR of green wheat was 0.12 dm on 9 April, 1.47 dm on 28 April, 2.96 dm on 15 May and 5.08 dm on 25 May. Wheat growth was slightly earlier than average during 1990 and increased rapidly (Snyder 1984, 1990). Because of extremely hot, dry weather during June 1990, wheat harves.t started in late June, whereas the average harvest initiation date in northeastern Colorado is about 7 July. Thus, pheasant nests placed in green wheat had an increased probability of being destroyed or covered by straw and abandoned during wheat harvest in 1990 (Snyder 1984). Percent CRP and Pheasant Density Attempts to correlate pheasant crowing indices with the percentage CRP along pheasant crowing routes were initiated in 1989 (Snyder 1990). However, in spring 1990 data were. inadequate (3 routes completed) in northeastern Colorado preventing detection of any relationship, if it existed. Crowing count census was more complete in southeastern Colorado, but again, no relationship with CRP was evident (Table 12). Crowing indices and pheasant numbers remained low thr~ughout eastern Colorado in 1990 and there was no observed increase either in areas where CRP was common or sparse. Reproduction was poor in 1990 possibly because of June weather conditions, the early wheat harvest, or other unknown factors. �Table 12. Ring-necked pheasant crowing count indices (!calls/station) and the percentage of Conservation Reserve along established census routes, eastern Colorado 1986-90. Census route Stratun County Anilerst-Paoli Julesburg-Amherst Julesburg-Crook Holyoke-Fleming Wages-Haxtun Fleming-Leroy Eckley-Yuna Lonestar-Akron Sterling-Proctor Ft. Morgan-Narrows Platner-Elba Idal ia-Joes Bomy Reservoir Burlington North Smokey Hill Lamar-Bristol Las Animas Two Buttes Konatz-Stonington 1 1 1 1 1 1 1 1 1 6 2 2 2 2 2 3 Phi IIips Sedgwick Sedgwick-Logan Phill ips-Logan Phill ips-Yuna Logan Yuna Washington Logan Morgan Washington Yuna Yuna Kit Carson Kit Carson Prowers Bent Baca Baca 4 &5 3 3 % CR 1986 2.4 o <1.0 3.3 5.3 7.7 3.3 16.3 <1.0 2.7 3.3 2.5 0.9 3.2 0.5 5.4 1.7 33.3 12.0 8.8 4.1 6.2 1.3 11.5 16.0 7.6 9.3 1987 Crowing count index 1988 1989 1990 12.5 15.4 18.3 17.7 16.8 18.3 14.1 13.4 10.4 8.1 16.4 5.8 12.7 9.8 7.1 10.2 3.0 5.6 5.5 11.9 3.0 16.8 12.6 23.1 13.4 19.1 7.0 16.7 9.0 23.8 10.4 14.7 8.7 2.5 10.5 6.3 12.1 10.6 4.0 31.3 39.0 9.2 7.8 15.7 14.5 8.7 7.2 6.1 2.7 6.3 2.9 2.9 21.0 19.2 8.1 12.6 14.7 2.0 10.6 2.7 20.9 9.6 ·Percent CRP was determined using a 1 or 2 mi.-wide strip bisected by the census route. LITERATURE CITED Snyder,_ W. D. 1984. Ring-necked pheasant nesting ecology and wheat farming on the High Plains. J. Wi1d1. Manage. 48:878-888 _________1989. Evaluation of habitat quality on conservation reserve lands in eastern Colorado. Colorado Div. Wi1d1., Wi1d1. Res. Rep., Fed. Aid Proj. W-1S2-R. Apr. 221-244. _________1990. Evaluation of habitat quality on conservation reserve lands in eastern Colorado. Colorado Div. Wildl., Wildl. Res. Rep., Fed. Aid Proj. W-1S2-R. Apr. 205-223. Prepared by -;1tJdJp,) ¥ Warren D. Snyder �JOB PROGRESS REPORT Colorado State of: Project: W-152-R Upland Bird Research Work Plan: 21 Job Title: Evaluation of Wildlife Responses to the Conservation Reserve Program Period Covered: Author: Job _6_ 01 January through 31 December 1990 Thomas E. Remington Personnel: Clait E. Braun, Thomas E. Remington, Warren D. Snyder, David A. Wilson, Colorado Division of Wildlife ABSTRACT Breeding birds were counted along line transects within 27 Conservation Reserve Program (CRP) fields throughout northeastern Colorado. Densities of breeding birds were computed from counts using a Fourier series estimator. Horned larks (Eremophila alpestris) occurred in 19 (of 27) fields sampled at an average density of 6.9 ± 1.3 birds/lO ha. Lark buntings (Caiamospiza melanocorys) were present in 24 fields.at an average density of 6.1 ± 7.9 birds/lO ha. Meadowlarks (Sturnella neglecta) occupied all 27 fields (density 1.9 ± 3.2 birds/lO ha). Mourning doves (Zenaida macroura) were common but many probably went undetected because of their inconspicuous breeding behavior. They were found in just over half of the fields sampled at an average density of 3.0 ± 8.3 birds/lO ha. Grasshopper sparrows (Ammodramus savannarum) were common and abundant (25 of 27 fields; density 4.0 ± 8.7 birds/lO ha), probably because of maturing cover in fields. Breeding birds found in a few fields included ring-necked pheasant (Phasianus colchicus), Cassin's sparrow (Aimophi1a cassinii), dickcissel (Spiza americana), upland sandpiper (Bartramia longicauda), red-winged blackbird (Agelaius phoeniceus) and lark sparro:w (Chondestes grammacus). Dickcisse1s and red-winged blackbirds bred and pested wlthin fields only if tall; ,structurally ~obust plants such as sweet cLover-or alfalfa were present;. ,Other birds observed' were migrating (vesper sparrow [Pooecetes.. gramineus], white-crowned sparrow [Zonotrichia leucophrys], song sparrow [Melospiza melodia]), or nested in adjacent rangeland or shelterbelts (loggerhead shrike [Lanius ludovicianusJ, eastern and western kingbird [Tyrannus tyrannus and T. verticalus]). Rope drags were used to locate 194 nests of 8 species. Common nesting species were lark bunting (106 nests), mourning dove (60), meadowlark (9), grasshopper sparrow (6), horned lark (5), and red-winged blackbird (4). Some species were under-represented because peak of nesting occurre~ before we searched (horned larks and meadowlarks), or because of their inconspicuous response to the rope drags (grasshopper sparrows). ��Evaluation of Wildlife Responses to the Conservation Reserve Program Thomas E. Remington P. N. OBJECTIVES 1. Measure and compare avian use of CRP to use of alternative .(wheat and summer fallow). 2. Measure and compare nesting wheat and summer fallow. 3. Relate patterns characteristics land uses success of birds on CRP to success of avian use and nest success and surrounding land uses. on in CRP fields to cover SEGMENT OBJECTIVES 1. Measure and compare densities of birds breeding in green wheat, wheat stubble, and Conservation Reserve Program fields. 2. Measure and compare nesting success of birds nesting wheat stubble, and CRP fields; 3. Relate patterns characteristics 4. Capture and attach transmitters to 40 pheasant hens; periodi~ally relocate to determine extent, timing and type of use of CRP fields. 5. Compile in green wheat, of avian use and nest .success in CRP fields to cover and surrounding land uses. and analyze data, and prepare progress reports. METHODS A subset of CRP fields randomly selected by the U.S. Fish and Wildlife Service (from the universe of all CRP fields in eastern Colorado) was randomly chosen for study. A sample of fields in which the Colorado Division of Wildlife cost-shared on a wildlife grass seed mixture was added for comparison. Pe rmi.s.sLonto e?ter and measure bird abundance within these fields was obtained via letter, and usually by· telephone, from landowners. CRP, and some green wheat and wheat stubble· fields were sampled within an hour of sunrise to count breeding birds. A 0.8-km long transect was established .near the midpoint of each field with plastic flags. An observer walked along the transect line slowly watching and listening for birds. Birds observed were identified to species and. the perpend{cular distance from each bird to the line transect was measured to the nearest meter using a rolotape. Each field was censused once between 20 April and 20 May and again between 21 May and 20 June to ensure both early (horned larks, meadowlarks) and late (lark buntings, grasshopper sparrows) breeding species were counted. Breeding bird density was estimated from perpendicular distance measures (from the highe;r of the 2 counts) using a Fourier series estimator (Burnham et al. 1980, 1981). �Eight hectares within CRP fields were searched for nesting birds by dragging a 30-meter long rope between 2 ~bservers. The area around the point a bird flushed was searched intensively for a nest. Each field was searched 2-3 times throughout the breeding season in an attempt to document nesting by all birds using the field. We attempted to revisit each nest at 7-day intervals to evaluate nest success; this was not possible for all nests because of time constraints. RESULTS AND DISCUSSION Fifteen species of birds were observed along line transects within CRP fields, but only 6 species were common resident breeders (Table 1). Horned larks were the most abundant breeding bird while meadowlarks were the most ubiquitous, -i.e., they occurred in the most fields (27 of 27). Lark buntings were second in abundance and ubiquity (number of fields in which present). The relative importance of these sp~cies was indicative of the generally poor condition of the grass stand and cover within these fields. Grasshopper sparrows were relatively common, especially in fields with better cover. Cassin's sparrows were commonly observed in 1989 in fields that were planted to native bunchgrasses. We observed only 5 in 3 fields in 1990, primarily because fields -in northeast Colorado were planted to smooth brome or because cover had yet to develop in fields planted to bunch grasses. Mourning doves were fairly common in fields with low, sparse cover, but were probably under represented because of their tendency to display on telephone wires or from elevated perches near field edges. Dickcissels were observed while singing in only 1 field where sweet clover was abundant. Vesper sparrows were frequently observed in late April and early May, but were not observed later and were presumed to be using CRP fields while migrating. Occasional use of CRP fields by species that nested elsewhere (in trees or shrubs) was noted. These species included lark sparrow), northern oriole (Icterus ga1bula), American robin (Turdus migratorius), loggerhead shrike, and eastern and western kingbirds. Nests and/or broods of 8 species were found during searches of 29 fields. These were lark bunting (106), mourning dove (60), horned lark (5), meadowlark (9), pheasant (1), grasshopper sparrow (6), red-winged blackbird (4), and lark sparrows (3). Cassin's sparrow nests were detected in 1989, but not in 1990. Nest success estimates have not yet been calculated. The number of nests found for each species was not necessarily indicative of breeding density or effort. Horned larks and meadowlarks were probably .under represented because most nest searching was conducted after the peak of nesting for these species. The peak of nesting effort by horned larks in 1989 was late May. In 1990, despite intensive searching beginning in late April, we found only 5 horned lark nests, 4 of these were apparently second nest attempts found on 14 June. Either 1989 was a relatively late year or 1990 was a relatively early year for horned lark nesting. Grasshopper sparrow n~sts were difficult to find because birds either ran off nests prior to flushing or didn't flush in response to the rope. Most of the 6 grasshopper sparrow nests were found when a bird flushed off the nest because we walked within 1 meter. Only one pheasant nest was located in 1990. While the quality of cover for nesting within these fields was generally poor, it was also pos~ible that pheasant hens did not flush in response to the rope. Nest densities of mourning doves were more indicative of dove use of CRP fields than breeding density estimates from the line transects. �Table 1. Number observed, breeding density (birds/10 ha), and percentage of sampled Conservation fields in which birds were observed, 1990. Species Lark bunting Grasshopper sparrow Horned lark Yes tern Meadowlark Mourning dove Red-winged blackbird Vesper sparrow Cassin's sparrow Ring-necked pheasant Yestern kingbird Dickcissel Song sparrow Upland sandpiper White-crowned sparrow Eastern kingbird N Observed Frequency 226 153 140 108 35 24 8 5 4 4 4 4 3 1 1 89 93 70 100 56 41 22 11 15 11 4 7 11 4 4 % Density ! so 6.1 4.0 6.9 1.9 3.0 Conments 7.9 8.7 1.3 3.2 8.3 Breeding/migration Seen during migration Bunchgrass fields 1 field only Migrating Migrating The birds.breeding in CRP fields, at this point in the program, primarily represent habitat generalists rather than grassland or grassland/shrub species. Relatively few line transects or nest searches were conducted in green wheat or wheat stubble in 1990 to increase sample sizes in CRP f~elds. However, it was apparent that these habitats were used for breeding by lark buntings, horned larks, mourning doves, pheasants, and perhaps grasshopper sparrows .. These are also the species commonly using CRP fields. Thus, the benefits of this program to breeding birds are unclear. Woody plantings within CRP fields shou14 enhance diversity of breeding birds. Lark sparrows, loggerhead shrikes, American robins, mourning doves, and red-winged blackbirds would be expected to use CRP (or use it more extensively) for breeding if woody plantings were present. Attempts to capture and radio-mark pheasant hens to quantify pheasant use of CRP fields, versus alternative cover types, for nesting and brood rearing were not successful., Additional trapping techniques will be attempted in winter 1990-91. LITERATURE CITED Burnham, K. P., D. R. Anderson, and J. L. Laake. 1980. Estimation of . de·risityfrom line transect sampling of biological populations; Wildl. Monogr. 72. 202 pp. ___ , , and 1981. Li.ne transect estimation of bird population density using a fourier series. Studies Avian BioI. 6:466-482. Thomas E. Remington Wildlife Researcher B ��313 INTERIM FINAL REPORT State of: Colorado Project: W-152-R Work Plan: 21 Job Title: Author: : Job _7_ Avifauna Period Covered: Upland Bird Research Responses to Grazing 01 January through 31 December 1990 Cynthia P. Melcher Personnel: C. E. Braun, K. M. Giesen, T. E. Remington, Colorado Wildlife; C. P. Melcher, Colorado State University Division of ABSTRACT The hypothesis that high densities of elk (Cervus elaphus) in Rocky Mountain National Park had contributed to observed declines in breeding densities of white-tailed ptarmigan (Lagopus leucurus) was investigated. Willows (Salix spp.) are essential as food and cover for ptarmigan, and may have been impacted in areas heavily used by elk. Relationships between ptarmigan, elk, and willow were assessed by measuring occurrence of ungulate feces, willow characteristics, and ptarmigan foraging ecology/reproductive success during 1989 and 1990. Four study areas (17 - 22 ha) were selected in alpine/ krummholz habitat near Trail Ridge Road. Numbers of breeding Ptarmigan had declined at two sites, but not at the other two sites. Density and species richness of alpine/willow passerines were measured to establish baseline information against which future trends may be compared. Ungulate feces were more abundant (f < 0.01) in areas where ptarmigan had 4eclined. Willow characteristics hypothesized as important to foraging ptarmigan (willow patch perimeter/diameter, height, density of buds, and unbrowsed terminal leaders), did not differ in 'a consistent .and predicted pattern between high and low elk density sites. However, extreme high and low values were generally observed at sites where ptarmigan densities had declined and moderate values were observed at sites where densities had remained relatively stable. Lengths of unbrowsed terminal leaders were greater (f < 0.01) at sites where frequencies of ungulate feces were greater. Differences were not detected among other willow characteristics thought to be important indicators of heavy browsing. Avian species richness was greater in sites where ptarmigan had declined. Species suspected of using sites for feeding only, but which were observed at sites regularly during censuses, contributed to species richness and density. Twelve ptarmigan hens were marked with radios. One disappeared, one fledged 4 chicks, and the remaining 10 were unsuccessful. Hens spent 48.8% of their time foraging (23.4 to 95.9%), and an average of 26% of their time sitting/resting/sleeping. Hen foraging rates averaged 32.6 bites/minute (range 24.3 to 48.0) when foraging on shrub willow. No salient patterns emerged for hens among sites, possibly due to small sample size. A thesis �314 incorporating two manuscripts for publication and two appendices will be submitted by 31 December 1991 in partial fulfillment of the requirements for a Master of Science degree in Biology at Colorado State University. Prepared by C~;;'~:ic~· 1(VLc0..C/~ Graduate Research Assistant Approved bY~(. Thomas E. Remington Wildlife Researcher �315 JOB PROGRESS REPORT Colorado State of: Project: W-152-R Upland Bird Research Work Plan: 22 Job Title: Upland Bird Research Publications Period Covered: Author: Job _l_ 01 January through 31 December 1990 Clait E. Braun Personnel: Clait E. Braun and Richard W. Hoffman, Colorado Division of Wildlife ABSTRACT The following articles were published in 1990: Braun, C. E. 1990. Effects of regulations on sage grouse harvest and population size. Annu. Mtg., Central Mtns. and Plains Sect., The Wildlife Soc. 35:Abstract. 1990. Review of "Adaptive strategies and population ecology of northern grouse". A. T. Bergerud and M. W. Gratson, eds. Univ. Minnesota Press, Minneapolis, 1988:809pp. Wilson Bull. 102:191-192. 1990. Summary remarks of "Introductions and reintroductions of wildlife populations. Trans. No. Am. Wi1dl. and Nat. Resour. Conf. 55:633-634. Cade, B. S., and R. W. Hoffman. 1990. Winter Use of Douglas-fir forests by blue grouse in Colorado. J..Wildl. Manage. 54:471-479. Hoag, A. W., and C. E. Braun. 1990. Status and distribution of plains sharptailed grouse in Colorado. Prairie Nat. 22:97-102. Hoffman, R. W. 1990. Chronology of gobbling and nesting activities of Merriam's wild turkeys. Proc. Nat1. Wild Turkey Symp. 6:25-31. Schmutz, J. A., C. E. Braun, and W. F. Ande1t. 1990. Brood habitat use of Rio Grande wild turkeys. Prairie Nat. 22:177-184. VanSant, B. F., and C. E. Braun. 1990. Distribution and status of greater prairie-chickens in Co1orad~. Prairie Nat. 22:225-230. White, J. A., and C. E. Braun. 1990. Growth of young band-tailed pigeons in captivity. Southwest. Nat. 35:82-84. Prepared by _~&_V_<_~____.. ~u::::.._,--....:..;:_ __ C1ait E. Braun ��':)J.I JOB PROGRESS REPORT State of: Project: Colorado W-152-R Upland Work Plan: 25 Job Title: Evaluation Fannin Period Covered: Bird Research Job _1_ of Wildlife 01 January Responses through 31 December to Pesticides Used in Wheat 1990 Author: Thomas E. Remington Personnel: Clait E. Braun, Carol A. Mehaffy, Michael W. Miller, Thomas E. Remington, Joan D. Ritchie, Lyn Stevens, David A. Wilson, Colorado Division of Wildlife; James Echols, Wendy Meyer, Frank Peairs, Stan Pilcher, Colorado State University; John Pearson, Claude Ross, Ted Warfield, FMC Corporation. ABSTRACT The impacts of two methods using pesticides to control insect pests in winter wheat on bird communities were investigated. These were aerial spraying of Lorsban (chlorpyrifos)'or Di-Syston (disulfoton) to control Russian wheat aphids (Diuraphis noxia) in spring and microtubule injection of Furadan (carbofuran) at planting to control grasshoppers. No dead or impaired birds were found during a search of 16 ha within a wheat field sprayed with Lorsban. Searchers located 5 of 8 carcasses placed in fields to evaluate search efficiency. Spraying of Di-Syston or Lorsban had no effect (f < 0.05) on 24 or 48-hour survival of pheasant chicks in a controlled experiment. Spraying of Di-Syston or Lorsban to control Russian wheat aphids in spring does not appear to impact birds significantly. Two horned larks (Eremophila alpestris) were found dead during searches of 27 km around the perimeters of 8 fields·710 and 14-21 days after seed planting and microtube injection of Furadan. One horned lark appeared to have been hit by a car. Carbamate resi~ues in grasshoppers averaged 1.31 mg /kg , a level unlikely t e .cause av i an mo rt aLL ty. Canada geese (Branta canadensis) largely rej ected 'Furad.im-treated' wheat in a controlled experiment. About 34 g of wheat remained in 0.785 m2 plots in the treatment pen vs. 2 grams in the untreated pen. Brain cholinesterase activity of Canada geese exposed to Furadan-treated wheat was unaffected (f> 0.05), although plasma cholinesterase activity was depressed about 38%. ��EVALUATION OF WILDLIFE RESPONSES TO PESTICIDES USED IN WHEAT FARMING Thomas E. Remington INTRODUCTION Wheat is the predominant cultivated crop in Colorado with upwards of 3 million acres·planted each year. Wheat fields are used extensively for foraging. and or breeding by a diverse assemblage of wildlife including ring-necked pheasant (Phasianus colchicus), horned larks, lark buntings (Calamospiza melanocoIYs), mourning doves (Zenaida macroura), Canada geese, and pronghorn (Antilocapra americana). Russian wheat aphids have caused extensive damage to wheat in Colorado since arriving in 1985. Consequently, massive aerial spraying has been conducted to control aphids; as much as 45% of planted wheat has been treated annually. Aerial applications of Di-Syston or Lorsban (chlorpyrifos) have emerged as the predominant treatment methods. Both are highly toxic organophosphate pesticides with the potential for wildlife mortality (Smith 1987). Microtubule injection of Furadan is a relatively new technique for controlling grasshopper depredation on immature winter wheat in fall. This technique has also been shown to be.effective in controlling aphids in wheat (Guerra-Sobrevilla 1988). Microtubule injection has several advantages (from a wildlife perspective) compared to more conventional methods of pestici~e application .. The pesticide is applied only as a narrow border treatment (typically 12-14 rows) and is injected as.a liquid 5 cm deep in the soil around the seed; consequently wildlife exposu~e is minimized. Furadan is a systemic insecticide which is highly toxic to wildlife (Flickinger et al. 1980, James 1987, Smith 1987, Littrell 1988). Previous bioassays of immature winter wheat. treated by microtubule injection of Furadan have shown significant insecticidal activity into April. While this has positive benefits for control of grasshoppers and/or aphids, it suggests that Furadan residues or metabolites persist overwinter and indicates a potential for significant wildlife exposure. Wildlife potentially at risk of significant exposure to this pesticide would be those that feed directly on exposed seeds or immature wheat,. or on grasshoppers (or other insects) that feed on wheat. Horned larks and meadowlarks (Sturnella magna) feed on exposed wheat seeds. Pronghorn and Canada geese fe,ed on winter wheat extensively from late'fall until early' spring. Several insectivorous birds, primarily eastern and western kingbirds (Tyrannus tyrannus and I. verticalis), American kestrels (Falco sparverius), burrowing owls (Speotyto cunicularia), and loggerhead shrikes (Lanius ludovicianus) ,.could be expected to feed on contaminated grasshoppers and may be at some risk. Risks may be mitigated for some species by timing of fall migrations. However Swainson's hawks (Buteo swainsoni) assemble in large premigratory and migratory aggregations within farmland and rangeland of eastern Colorado and feed extensively, if not exclusively, on grasshoppers (Bailey and Niedrach 1965, Woffinden 1986, Johnson et al. 1987). The purpose of this study was to evaluate the impacts on avian wildlife of aerial spraying to control aphids and microtubule injection of Furadan to �320 control grasshoppers or aphids. Emphasis was on ascertaining direct mortality but indirect effects such as cholinesterase depression were also investigated. P. N. OBJECTIVES 1. Determine acute mortality of wildlife 1-3 days post-spray resulting from prescribed levels of Di-Syston and chlorpyrifos. 2. Recover carcasses of wildlife suspected of dying from pesticide poisoning for analysis of cause of death and pesticide residue levels. 3.' Monitor impacts of spraying prescribed levels of Di-Syston or ch1orpyrifos on avian nesting success. 4. Determine level of brain cholinesterase depression in songbirds and pheasants 24-48 hours post-spray as an index to both pesticide exposure and potential effects. 5. Measure toxicity of prescribed levels of Di-Syston and chlorpyrifos to 7-10 day-old pheasant chicks. SEGMENT OBJECTIVES 1. Measure acetylcholinesterase activity in brain tissue of carcasses found dead in, or collected from, wheat fields during fall 1999. 2. Conduct pesticide residue analysis of tissues from birds found dead in wheat fields and exhibiting ~ sox brain acetylcholinesterase inhibition. 3. Search wheat fields for dead or moribund wildlife following application of Di-Syston, chlorpyrifos, and possibly carbofuran. 4. Determine rates of carcass removal by scavengers, and carcass detection by search crews. 5. Compile and analyze data, and prepare progress reports. METHODS Wheae Aphid Study Two research approaches were used during this period. Transects were conducted to search for dead or impaired wildlife in sprayed fields. Acute toxicity and indirect effects of these pesticides on survival of pheasant chicks was evaluated by experiment. Specific methodology for each approach follows. Transects were conducted by 4-5 people walking abreast, about 20 rows apart 13 days post-spray until 8.1 ha had been searched per field. Most searches were conducted with the rows, although it was found that as wheat grew taller visibility of carcasses was greatest walking against the rows. Search efficiency was measured as the percent recovery of house sparrows (Passer dornesticus) placed in sprayed fields prior to the search. '_ �A randomized complete b~ock design was used in the pheasant chick experiment (Fig. 1). Twelve strips, 244 m long by 55 m wide, were marked with flagging within a 24-ha wheat field about 3 km south and 3 km east of Akron, Colorado. A 27-m buffer strip was marked between strips to prevent drift of pesticide across treatments. Treatments, Di-Sys-ton, Lorsban, or unsprayed control, were randomly assigned to 1 of 3 strips within each of 4 btocks. 'Within each strip, 2 of 16 possible 0.1 ha (1/4 acre) pen locations were randomly selected. Pens were constructed of 61 by 2.54 cm (24" by 1") mesh poultry nettin~ supported by rebar and aluminum rods. Within the center of each pen a 9.75-m circular pen was constructed of 1.22 m (48") hardware cloth. Hot boxes were constructed of 46 or 51 cm (18 or 20") diameter galvanized duct pipe, covered with fiberglass insulation and clear plastic and placed in each circular hardware-cloth pen. Hot boxes were heated to 32 C (90 F) by l25-watt heat; lamps suspended at the top and powered by 3 generators. Line voltage thermostats were used to maintain a temperature of approximately 32 C. A door was cut into the bottom of each hot box to allow chicks access. Ten, 6-day old pheasant-chicks were placed in each pen from 0645 to 0730 hours. DiSyston and Lorsban strips were sprayed on 22 May with 1.12 kg active ingredient (a.i.) per ha or 0.84 kg a.i./ha, respectively. Two Pawnee PA 25 aircraft calibrated to apply treatments in 3.1 liters of spray volume per ha (2 gallons/acre) were used. Spraying began at 0740 and was completed by 0830 hours. Conditions were ideal for spraying; sunny, warm and little or no breeze. To facilitate recovery and prevent escape, pheasant chicks were initially placed in the small pens. Chicks were placed within the hot boxes near sunset each day and during inclement weather periods. They were provided pelleted chick feed and water ad libitum. Chicks were released from the hot boxes each morning around 1000 when air temperature had warmed. Carbofuran Study The purpose of this research was to gather preliminary information on mortality or morbidity of wildlife thought to be at risk from microtubule injection of Furadan as an at-planting treatment to control grasshoppers. Effects on passerine birds were evaluated by searching borders of treated fields (Furadan 4F at a rate of 14.8 ml per 305 linear meters) for dead or impaired birds at about 1 and 2 weeks after planting. Searcher efficiency was estimated as recovery of house sparrow carcasses placed within field margins prio,r to the search._ The effect on Canada geese of consumption of furadan-treated wheat was evaluated by placing birds into pens containing furadan-treated wheat or untreated wheat (control), allowing them to eat for 48 hours, and then sacrificing them and measuring brain cholinesterase activity. Geese (29) were captured while flightless on 4 June from the Loveland Golf course and maintained at the Foothills Wildlife Research Facility until the feeding trial. Birds were fed a commercial pelle ted chow (Purina Turkey Ration) , although they supplemented this by feeding on grass and weeds within their pen. Geese were wing clipped in late July to minimize injuries within the pen and to prevent escape from the welded wire pens in the wheat field. A similar experiment in 1989 was hampered by extremely low residues of Furadan in the treated wheat to which geese were exposed, either because of poor �BLOCK 1 BLOCK 2 BLOCK 3 BLOCK 4 meter buffer 55 meter spray Fig. 1 Design used in pheasant chick experiment. uptake, metabolism, or possibly erroneous measurement of Furadan residues by the contract laboratory. To insure high residue levels, representative of a worst case scenario, we planted wheat into sub-irrigated ground and exposed the geese 25-26 days after planting rather than 98-99 days as in 1989. Agri Pro, Inc., provided an irrigated field at their research farm about 4 km southwest of Berthoud, Colorado. Winter wheat (Sandy variety) was planted on 17 September 1990, at a rate of 16.2 kg per ha and a 0.3 m (12-inch) row spacing. Furadan 4F (14.8 ml per 305 linear meters) and liquid fertilizer (7.68 kg N, 26.1 kg P20S per ha) were applied in-furrow by micro-tubule injection. Two blocks of untreated wheat were planted slmilarly, although without}'uradan Lnjec t Lon (Fig. 2). Geese were transported,to the site on 10 October and released into a 47.2 m by 14.6 m (48 row) welded wire enclosure around untreated wheat. Geese were allowed to feed within this enclosure-for 2 days to acclimate them to a wheat diet and to conditions at the site. They were they moved into 1 of 2 adjacent 47.2 m x 7.3 m. (24 row) enclosures containing either Furadan treated (15 geese) or untreated wheat (14 geese). The birds were left within the pens for two days to feed. They were then killed by CO2 asphyxiation. Heads were removed, placed on dry ice, then transported to and stored within a freezer at -60 C. Brain and plasma acetylcholinesterase activity was determined following Hill and Fleming (1982). All remaining wheat above ground level was clipped and weighed from 10, 0.785-m2 circular plots randomly located within treated and untreated enclosures to measure feeding intensity. �J.t:.J Two 100 g samples of treated and untreated wheat were collected from outside the enclosures on the first trial day, kept frozen, and sent to A&L Mid West Laboratories for analysis of Furadan and Furadan metabolite residues. Analysis was by HPLC with a ultraviolet detector (no other details available) with a detection. limit of 0.1 ppm. Because of questions about the accuracy of the residue levels found by A&L, the samples were sent to the ACG Developmental Chemistry Department laboratory of FMC Corporation in Princeton, New Jersey for additional analysis. RESULTS and DISCUSSION (f) o w IT W I- I- ~ w '\ IZ « w IT LO ~ Russian Wheat Aphid Study Mortality Transects.--Sixteen hectares within one field sprayed with Lorsban on 2 May were searched on 3 May for dead or impaired wildlife. No dead or impaired birds or other animals were detected, although 5 of 8 birds placed to evaluate searcher efficiency were located. Aphid infestations were relatively light. Treatable infestations occurred near Pietz and north into.southern Wyoming for the .first' time. o W I(f) IT W IW « W IT I- o W I- « Spraying of Di-Syston apparently resulted in ,W z the deaths of 9 jack rabbits (Lepus ~ « IT Ica1ifornicus) about 19 kilometers southwest of o '\ Z « Pritchett in Southeast Colorado. The dead LO ~ IT jackrabbits were found in a shortgrass pasture :::) LL on 10 May, 1990, 1-30 m from a wheat field which had been sprayed late the day before. No dead jackrabbits were found within the wheat field. Jackrabbits are extremely sensitive to a metabolite of Di-Syston produced when the parent ·compound is 48 ROWS metabi;>1izedby .growing vegetation. A likely scenario would be that vegetati,on in 'the pasture was contaminated with Di-Syston by Fig. 2 Field design of overspray or drift. Jackrabbits feeding on Furadan-wheat, goose study. vegetation within the pasture would be exposed to a large dose of the metabolite of Di-Syston because the spray would be concentrated on the relatively short vegetation in the pasture. Jackrabbits have been observed within wheat fields sprayed wit:h Di-Syston and were apparently unaffected. They appeared to be using maturing wheat fields for cover while foraging in nearby pastures. Jackrabbits are probably not at significant risk if spraying is confined to wheat. �Pheasant Chick Toxicity.--Spraying of Di-Syston or Lorsban did not decrease (f An average of 9.7, 9.7, and 9.9 (of 10) chicks survived for 24 hours post-spray in pens exposed to Di-Syston, Lorsban, or unsprayed, respectively. Survival to 48-hours post-spray for these groups was 9.4, 9.1, and 9.5 chicks per pen, respectively. Survival of chicks was markedly improved from the experiment conducted in 1989. This was attributed to use of the hot boxes which allowed maintainenance of chicks at or near their preferred temperature and eliminated the need to capture chicks and transport them indoors. Di-Syston significantly reduced survival of chicks in the previous experiment but had no effect in this experiment. This supports the argument (Remington 1990) that the cold temperatures associated with a thunderstorm the afternoon of the day spraying occurred resulted in disproportionately more chicks sprayed with DiSyston dying. Cold stress can make birds more susceptible to carbamate pesticides (Rattner et a1. 1982). > 0.05) 24 or 48-hour survival of pheasant chicks relative to controls. A male lark bunting was found apparently sick and unable to fly about 7 hours after spraying near strip 12 which had been sprayed with Lorsban. This bird was placed inside one of the pens and apparently recovered as it was not found later. It may have been exposed to Di-Syston or Lorsban. Two mallard (Anas p1atyrhynchos) nests were discovered in the wheat field while we were building pens. These hens were each incubating 10 eggs and both were in strips sprayed, -one with Lorsban and one with Di-Syston. Both hens continued to incubate their clutches for at least a week post-spray. Data from the mortality transects and pheasant chick experiments indicate that significant avian mortality is unlikely when labelled rates of these two pesticides are sprayed to control aphids. Pheasant chicks younger than 5-6 days of age may be more susceptible to these pesticides. However, most spraying occurs before most pheasant eggs have hatched, particularly nests in green wheat. Most sp~aying occurs early in the morning before temperatures have warmed up and winds begin to increase. Chicks younger than 5-6 days are probably brooded by hens at this time and not directly exposed to pesticides. Carbofuran Study, Mortality Transects.--Twenty-seven kilometers around the perimeters of 8 fields were searched for dead or moribund birds within 7-10 days of planting and again 2-3 weeks after planting. Two dead horned larks were found. Upon examination, 1 carcass found adjacent to a road had injuries consistent with being; struck by an automobile. The other carcass was too degraded to yield useful fnformation to cause of death.' In 1989 two horned lark carcasses were recov~red in '~e,archesof 3,8'Ian around 13'treat~d fields '. S~arch~r efficiency was not evaluated this year,'but averaged 69% (25 of 36 carcasses recovered) in 1989. Efficiency within each field was 67, 75, 63, 87, and 60%. These results indicate that had significant mortality occurred, we would have detected it, assuming carcasses remained until our searches. This assumption was not tested directly during this study. Fifty percent of house sparrow carcasses were still present after 7 days during previous research in wheat fields in eastern Colorado during spring (Remington 1990). as It appears that mortality of passerines is negligible under this application method of furadan to the borders of fields. These 'results should be '-' �interpreted cautiously. An inherent weakness in this approach is that birds could feed within treated field margins, flyaway to die elsewhere, and go undetected during our searches. This could be a problem with horned larks that have large home ranges in fall and winter. Swainson's hawks were plentiful in and around treated fields during the period we conducted mortality transects. Examination of hawk scats indicated almost complete feeding on insects, predominately grasshoppers. We did not detect any dead, moribund, or abnormally behaving Swainson's hawks. Exposure of other insectivorous birds to furadan-contaminated grasshoppers was presumably minimal since few insectivorous birds were observed during our searches. Fall migrations may mitigate potential exposure of these birds to furadan, although the extent to which this occurs may vary annually. Furadan residues of composite grasshopper samples measured by A&L laboratories were below detection limits from 1 treated field and up to 30 times levels measured in 1989 from another. Residues measured by FMC Corporation's lab were repeatable, much less variable (Table 1), and verified by spiking check samples. Thus-residues measured by FMC were used for hazard assessments. Assuming a SO g (0.05 kg) bird, a grasshopper weight of 0.89 g (0.00089 kg), and total carbamate residues of 1.31 ppm (from Table 1), ingestion of a single grasshopper represented about 5.6% of the LDSO for·red-winged blackbirds (Agelaius phoeniceus) and about 1.9% of the LDSO for house ·sparrows. Swainson's hawks may eat 100 grasshoppers per day (Johnson et al. 1987). Assuming an intake of 100 grasshoppers with an ·average ~arbamate residue of 1.31 ppm, and a bird weight of 0.908 kg, Swainson's hawks would be exposed to 3.2% of an LDSO. These hazard assessments suggest little avian risk from consuming grasshoppers killed or injured by Furadan, and support the complete lack-of insectivorous bird carcasses recovered during mortality transects. Analysis of scats found at several treated fields indicated that striped skunks (Mephitis mephitis) were feeding extensively on grasshoppers along field margins. It is difficult to assess the potential impact to skunks of this exposure since information on how many grasshoppers they consume in a day and their sensitiv·ity to furadan is not available. LDSO's of dogs and rats are 19 and 11 mg/kg, respectively (Smith 1987). Using 10 mg/kg as an LDSO, and assuming a body weight of 3 kg and consumption of 100 or 500 grasshoppers per night, skunks would be exposed to 0.39 - 1.94% of an LDSO. If these residues are accurate, and these assumptions reasonable, mortality of skunks seems unlikely, Canada Goose Eneriment.--Geese adapted·well to experimental conditions and grazed the untreated wheat heavily during the 2 days of acclimation. Almost no wheat remained in this pen after two days. Geese within the control (untreated) pen continued to graze heavily following their transfer to this pen, but feeding was minimal in the pen with Furadan-treated wheat. Avoidance of Furadan-treated wheat continued through the second day, despite the fact that there was no other food source. Wheat (above ground) within the control pen was essentially eliminated by the conclusion of the trial. When wheat samples were clipped and weighed fr~m each pen the next morning, some recovery of grazed wheat was apparent. Still, only 2;03 ± 0.86 g remained in 0.785 m2 'plots in the control pen, significantly less (l < 0.05) than the 33.95 ± 9.33 g remaining in plots within the treatment pen. �Avoidance of Furadan-treated wheat is significant, because large die-offs of geese and other waterfowl have occurred when alfalfa treated with Furadan 4F f1owab1e was (apparently) eaten (Flickinger et a1. 1980, reviewed in Smith 1987). Canada geese have been successfully deterred from feeding on rye and turf by methiocarb (another carbamate pesticide) application (Conover 1985, 1989), but methiocarb is substantially less toxic to birds than Furadan. Carbamate residues in treated wheat samples, adjusted for percent recovery, were 5.81 and 6.08 ppm. Dietary LC50 for mallards is 190 ppm (Smith 1987), over 30 times higher than levels measured in wheat. Mallard LD50's are substantially lower, in the range of 0.4-0.6 mgfkg (Smith 1987). A 2.5-kg Canada goose eating 0.35 kg of green wheat with a total carbamate level of 5.7 mgfkg would be exposed to a dose of 0.8 mgfkg body weight, or in excess of a mallard LD50. Thus, if geese had eaten large quantities of green wheat in this trial some mortality might have occurred. It is interesting that geese apparently eat enough Furadan-treated alfalfa to poison themselves yet avoid wheat containing potentially lethal levels. A possible explanation is that geese don't reject Furadan-treated vegetation on the basis of taste, but rather because of post-ingestive consequences such as feeling ill. Geese may sample alfalfa sprayed with Furadan 4F, be exposed to a lethal dose and die. Sampling wheat in this study would have exposed them to a sub-lethal dose that may have made them sick enough to avoid additional feeding. Table 1. Furadan and Furadan metabolite residue levels (ppm) in winter wheat from a Canada goose study treatment field (treated with an at-planting microtubule injection of Furadan of 14.8 m1/305 meters) and in grasshopper samples collected (dead or dying) from similarly treated fields (percent recovery of spiked samples from each matrix indicated in parentheses). Sample Wheat 102 103 Carbofuran 2.86 (94.2) 2.48 Grasshoppers 927 919 0.16 (87.5) 0.35 aNot detected. 3-Keto Carbofuran NDa (95.7) ND 0.01 (89.0) 0.03 3-Hydroxy Carbofuran 2.62 (94.2) 3.25 0.71 (85.1) 0.73 �Acetylcholinesterase (ChE) activity of brain tissue from geese in treatment and control pens did not differ (l < 0.05, Table 2). Plasma ChE was depressed (l < 0.05) an average of about 38% in birds exposed to Furadan treated wheat. Plasma ChE inhibition is a sensitive indicator of exposure to antiChE agents but is not in itself indicative of negative health consequences because the function of plasma ChE is not known (Kutty 1980). Plasma ChE may be inhibited by as much as 75% when brain ChE reaches a detectable and biologically significant 10-20% (Ludke et al. 1975). These results support the premise that initial feeding on treated wheat exposed geese to Furadan, but feeding ceased prior to significant brain ChE depression. . Table 2. Brain and plasma acetylcholinesterase activity (mean ± SD) of Canada geese from pens containing Furadan-treated (n - 15) or untreated (n - 14) winter wheat. Plasmaa Untreated Treated 672.1 ± 201.9 419.9 ± 124.3 5.57 ± 0.83 5.58 ± 1.48 ~U acetylthiocholine iodide hydrolyzed per min·per ml of plasma at 25 C. b Jlmol acetylthiocholine iodide hydrolized/g (wet weight) of brain tissue at 25 C. Wildlife risks from microtubule injection of furadan appear slight. Residue levels in green wheat are low relative to LC50 or LDSO values of mallards or geese. Pronghorn tested in 1989 showed no aversion to treated wheat nor consequences from ingesting it. Geese avoided eating treated wheat and kept intakes below levels that would reduce brain ChE. Risks to insectivorous birds are mitigated by timing of migrations and low furadan residues in grasshoppers. The primary risk appears to be to granivorous birds, principally horned larks and meadowlarks. Few unexplained mortalities were found, suggesting that losses were slight or nonexistent. LITERATURE CITED Bailey, A. M., and R. J. Niedrach. 1965. Nat. Hist. Denver, Colo. 895 pp. Birds of Colorado. Denver Mus. Conover, M. R. 1985. Alleviating nuisance Canada goose problems through methiocarb-induced aversive conditioning. J. Wildl. Manage. 49:631-636. 1989. Can goose damage to grain fields be prevented through methiocarb-induced aversive conditioning? Wildl. Soc. Bull. 17:172-175. Flickinger, E. L., K. A. King, W. F. Stout, and M. M. Mohn. 1980. Wildlife hazards from Furadan 3G applications to rice in Texas. J. Wildl. Manage. 44:190-197. �Guerra-Sobrevilla, L. 1988. Effectiveness of carbofuran applied to the soil and as a seed treatment for the control of aphids on wheat in northwestern Mexico. Crop Prot. 7:336-337. Hill, E. F., and W. J. Fleming. 1982. Anticholinesterase poisoning of birds: field monitoring and diagnosis of acute poisoning. Environ. Toxicol. Chem. 1:27-38. James, P. C., and G. A. Fox. 1987. Effects of some insecticides on productivity of burrowing owls. Blue Jay 45:65-71. Johnson, C. G., L. A. Nickerson, and M. J. Bechard. 1987. Grasshopper consumption and summer flocks of nonbreeding Swainson's hawks. Condor 89:676-678. Kutty, K. M. 1980. 13:239-243. Biological function of cholinesterase. Clin. Biochem. Littrell, E. E. 1988. Waterfowl mortality in rice fields treated carbamate, carbofuran. Calif. Fish and Game 74:226-231. with the Ludke, J. L., E. F. Hill, and M. P. Dieter. 1975. Cholinesterase (ChE) response and related mortality among birds fed ChE inhibitors. Arch. Environ. Contam. and Toxicol. 3:1-21. Rattner, B. A.., L. Sileo, and C. G. Scanes. 1982. Hormonal responses and tolerance to .cold of female quail following parathion ingestion. Pest. Biochem. Physiol. 18:132-138. Remington, T. E. 1990. Evaluation of wildlife responses to pesticides used in wheat farming. Colorado Div. Wild!. Job Prog. Rep., Fed. Aid Proj. W-152-R. Apr:253-264. Smith, G. J. 1987. Pesticide use and toxicology in relation to wildlife: organophosporous and carbamate compounds. U.S. Dep. Inter., Fish and Wildl. Servo Resour. Publ. 170. l7lpp. Woffinden, N. D. 1986. Notes on the Swainson's hawk in central Utah: insectivory, premigratory aggregations, and kleptoparasitism. Great Basin Nat. 46:302-304. Thomas E. Remington Wildlife Researcher �329 JOB PROGRESS REPORT Colorado State of: Project: W-152-R Upland Bird Research Work Plan: 26 Job Title: Analysis Period Covered: Author: Job _1_ of Upland Bird Population 01 January through 31 December Trends 1990 Clait E. Braun Personnel: C1ait E. Braun, Ken M. Giesen, Thomas E. Remington, Snyder, Colorado Division of Wildlife Warren D. ABSTRACT The following were prepared Braun, C. E. 1990. 1990. 1990. counties, Blue Mountain Cold Spring Mountain Sage grouse harvest Colorado, 1976-90. sage grouse harvest harvest data, Eastern Moffat and Western Eagle County sage grouse harvest 1990. Gunnison 1990. Middle 1990. Northcentral 1990. North Park sage grouse harvest 1990. Piceance 1990. Yampa Area sage grouse harvest R. W. 1990. data, 1976-90. data, 1976-90. 1990. Giesen, K. M. Colorado, 1990. .Hoffman, in 1990. data, 1990. Basin sage grouse harvest Park sage grouse harvest Routt data, 1990. data, 1990. Moffat County sage grouse harvest data, 1976-90. data, 1990. Basin sage grouse harvest data, 1990. data, 1990. 1990. Columbian sharp-tailed grouse harvest data, northwest 1976-90. Lesser prairie-chicken breeding survey, 1990 . 1990. Blue grouse wing analyses, Blue grouse wing analyses, Gunnison Northeast Region. Basin. �330 1990. Blue grouse wing analyses, Northwest Region. 1990. Disease monitoring guidelines for Merriam's wild turkey in Colorado. 1990. Results of tests for Mycoplasma in wild turkeys trapped in the Northwest Region. 1990. Rifle versus shotguns only for hunting wild turkey. Remington, T. E. Mountain. 1990. Analysis of blue grouse harvest trends on Blue Prepared by Clait E. Braun Wildlife Research Leader � https://cpw.cvlcollections.org/files/original/231b7e34bd7af6897431f00757ef261b.pdf 1c66cb0e132bc9434714d9cdd1176e1f PDF Text Text 1 Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~ _ Project No. W-1S3-R-4 Mammals Research Work Plan No. Multispecies Investigations Job No. Period Covered: Author: Mammals Publication, Editing, and Libraty Services 7 July 1, 1990 - June 30, 1991 J. A. Boss Personnel: J. A. Boss, N. W. McEwen . Abstract • 'Dul;:ingthe i990-91, Segment· 3·pub1~cations were purchased wi~h .Mamma1s -~esearch funds for' the Research Library, "13 publi-cations were acqui red ac BO cost, -and 20 theses were obtained via Interlibrary Loan or as gifts. _-Mammals Research staff had 13 manuscripts published in scientific journals or symposia proceedings. An additional 6 manuscripts were submitted for peer review in anticipation of publication. .r: ��3 MAMMALS PUBLICATION. EDITING AND LIBRARY SERVICES Jacqueline A. Boss P. N. OBJECTIVE To provide a centralized support program for manuscript editing and library services to facilitate publishing results of research conducted by staff of Federal Aid Project W-153-R. SEGMENT OBJECTIVE To provide a centralized support program for Mammals Research editing, library, and publishing services so that Mammals Research personnel can be most efficient in publishing results of their research. SUMMARY OF SERVICES Publications Purchased with Mammals Research Funds and Placed in the Research Center Library Bromley, M. 1989. Bear-people conflicts: proceedings of a symposium on management strategies. Northwest Territories Dept. of Renewable Resources. Yellowknit:~, Northwest "TerritorIes, Cattada. 246pp. Hoage, R.-J. 1989. Perceptions of animals in American culture. Institution Press. Washington, DC. l51pp. Forest, L. R. 1988. Field guide to tracking animals in snow. " Books. Harrisburg, PA. 185pp. Smithsonian Stackpole Publications Obtained Free or at Low Cost In addition to books purchased with Federal Aid Funds, about 13 free reports and short publications from state or federal agencies or from private sources were located, ordered, and obtained for use by Mammals Research personnel. Theses Purchased. Obtained on Interlibrary Loan or as Gifts for Use by Researchers Allen, R. B. 1985. Research and management implications of the pursuit of black bears with trained dogs. M.S. Thesis, University of Montana, Missoula. 51pp. Allred, W. S. 1989. The effects of Abert squirrel herbivory on ponderosa pines. Ph.D. Dissertation, Northern Arizona University, Flagstaff. 107pp. "Alt, G~_".L. 1989._ Reprodu~ti:v~"bio10gy .of female_black bears and early gro~th " _ and development of cubs in nortnwestern Pennsylvania. Ph.D. Dissertation, West Virginia University, Morgantown. 127pp. �4 Ball, L. C. 1989. Efficiency of nutrient and energy assimilation from mice and himalaya berries by gray foxes. M.S. Thesis, Humboldt State University, Arcata, CA. 59pp. Borden, D. L. 1990. Behavioral response of raccoons (Procyon lotor) to experimental manipulation of density. M.S. Thesis, Tennessee Technological University, Cookeville. 38pp. Bown, R. R. 1988. Beaver habitat along rivers and reservoirs in central Montana. M.S. Thesis, University of Montana, Missoula. Cassirer, E. F. 1990. Responses of elk to disturbance by cross-country skiers in northern Yellowstone National Park. M.S. Thesis, University of Idaho, Moscow. 101pp. De Marais, B. D. 1986. Morphologic variation in Qils (Pisces: Cyprinidae) and geologic history: lower Colorado River basin. M.S. Thesis, Arizona State University, Tempe. 85pp. Easter-Pilcher, A. L. 1987. Forage utilization; habitat selection, and population indices of beaver in northwestern Montana: M.S. Thesis, University of Montana, Missoula. 88pp. Evenden, A. G.- 1989, Ecology and distribution of riparian vegetation in the Trout Creek Mountains of southeastern Oregon. Ph.D. Dissertation, Oregon Sta~e University, Corvallis. 156pp. Gentile'- J. R. - 1983. The evolution and geographic aspects of the' antitrapping movement: -a classic resource cbnf1icc. -Ph.D. Dissert~tion, --Oregon State University, Corvallis. l45pp. Herriges, J. D. 1986. Movement, activity and habitat use of white-tailed deer along the lower Yellowstone River. M.S. Thesis, Montana State University, Bozeman. l32pp. Hewitt, D. G. habits. 1989. Correcting grizzly bear fecal analysis to observed food M.S~ Thesis, Washington State University, Pullman. 20pp. Keay, J. A. 1990. Black bear population dynamics in Yosemite National Park. Ph-.D. Dissertation, University of Idaho, Moscow. 126pp. Loy, R. R. 1981. An ecological investigation of the swift fox, (Vulpes velox) on the Pawnee National Grasslands, Colorado. M.A. Thesis, University of Northern Colorado, Greeley. 64pp. Neal, A. K. 1990. Evaluation of mark-resight population estimates using simulations and field data from mountain sheep. M.S. Thesis, Colorado State University, Fort Collins. 198pp. Reeves, K. A. 1989. Summer diet and status of river otters on Redwood Creek. M.S. Thesis, Humboldt State University, Arcata, CA. Rohlman, J. A. 1989. Black bear ecology near Priest Lake, Idaho. .'rhesis,_~iv!_~sity of Idaho, Mos.cow. 76pp. M.S . �5 Travis, S. E. 1990. Resources and sociality: effects of food resource variations on the mating system of Gunnison's prairie dog (Cynomys iUDDisoni). M.S. Thesis, Northern Arizona Univers~ty, Flagstaff. 63pp. Yeager, B. 1984. Use of cover by mule deer on a western Montana winter range. M.S. Thesis, University of Montana, Missoula. 76pp. Reference Document Location and Delivery The Research Center Library staff also located and delivered about 878 individual articles on request for Mammals Researchers during this segment; about 19 were not available locally and were obtained through Interlibrary Loan procedures. Manuscripts Published in FY 1990-91 Job Progress Reports; Federal Aid. All studies. Anderson, A. E. 1991. Frequency of mountain lion sightings by residents and employees of a housing development. (Abstract). Mountain Lion-Human Interactions Workshop and Symposium. Colorado Division of Wildlife, Fort Collins. (in press). Bear, G. B. 1990. A century of Colorado elk. Co~o. Outdoors 39(5):5-7. ·Carpenter,.L.·H.'. 19!H. Elk hunting regulations: 'the Colorado experience. Elk Vulnerability Symposium. Montana State University, Bozeman£ (in press). Gill, R. B .• and T. D. 1. Beck. 1991. ·W. Black Bear Workshop, Proc. 7. Black bear status report: Colorado. (in press) . Hobbs, N. T., and M. W. Miller. 1991. Interactions between pathogens and hosts: simulations of population regulation in bighorn sheep. in D. R. McCullough, ed. Wildlife 2000: populations. Elesevier Scientific. (in press). _____ , D. S. Schimel, C. E. Owensby, and D. J. Ljima. 1991. Fire and grazing in the tall grass prairie: contingent effects on nitrogen budgets. Ecology. (in press). Miller, M. W., N. T. Hobbs, and E. S. Williams. 1991. Spontaneous pasteurellosis in captive Rocky Mountain bighorn sheep (Ovis canadensis): clinical, laboratory, and epizootiological observations. J. Wildl. Dis. 27. (in press). O'Brien, S. J., M. E. Roelke, M. Yuhki, K. W. Richards, W. E. Johnson, W. L. Franklin, A. E. Anderson, O. L. Bass, Jr., F. C. Belden, and J. S. Martenson. 1990. Genetic introgression within the Florida panther (Felis concolor coryi). National Geographic Res. 6(4):485-494. Pojar,_ T. M., an4 R. B. Gill. _ 1990. Harvest management options for a pioneering pronghorn popUlation. Pronghorn Antelope Workshop, Proc. 14:112-122. . �6 Reed, D. F. 1990. Mirror-image stimu1ation--what can we ascertain about mountain goat social structure? Bienn. Symp. North Wild Sheep and Goat Counc. 7:274-281. Scribner, K. T., M. H. Smith, R. A. Garrott, and L. C. Carpenter. 1991. Temporal, spatial, and age-specific changes in genotypic composition of mule deer. J. Mammal. 72(1):126-137. Wild, M. A., and M. W. Miller. 1991. Detecting nonhemo1ytic Pasteurella haemglytica infections in healthy Rocky Mountain bighorn sheep (Ovis canadensis): influences of sample site and handling. J. Wildl. Dis. 27:53-60. ______ , and M. W. Miller. 1981. Bottle-raising wild ruminants in captivity. Outdoor Facts, No. 114. Colorado Division of Wildlife, Fort Collins. 6pp. Manuscripts in Review FY 1990-91 Andelt, W. F., D. L. Baker, and K. P. Burnham. 1991. Relative effectiveness of repellents for reducing elk damage. J. Wild1. Manage. (in review). Bartmann, R. M.·, G. C" White, and L. H. Carpenter·. 1991. Compensatory mortality in a Colorado mule deer population. Wildl. Monogr. (in review) • Pojar:. T.·M. 1991. 'CensUs technique~:' in R. McCabe, ed. Pronghorn management. Wildlife Management Institute, Washington, DC. (s~bmitted 6 Mar. 1991). 1991. The use of population models. in R. McCabe, ed. Pronghorn management. Wildlife Management Institute, Washington, DC. (submitted 6 Mar. 1991). ____ , D. C. Bowden, and R ..B. Gill. 1991. Evaluation of census techniques for pronghorn~ J. Wildl. Manage. (in review). Wild, M. A., M. W. Miller', D. L. Baker, R. B. Gill, N. T. Hobbs, and B. J. Maynard. 1991. Comparison of growth rate and milk intake of ·bott1e raised and dam-raised bighorn sheep, pronghorn antelope, and elk neonates. Can. J. Zool. (in review). o Prepared by ,~'~ (J ~ .; ABoJ.L ~~~ ac~lEline A. Boss ibUian �7 Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~ _ Project No. W-lS3-R-4 Mammals Research Work Plan No. 1 Multispecies.lnvestigations Job No. 9 Mammals 1 Research Administration Period Covered: Author: July 1, 1990 - June 30, 1991 R. B. Gill Personnel: R. B. Gill, L. E. Lovett Abstract Accomplishments ~f this Job are summarized in the Job Progress Report for W-lS3-R-4 Work Plan ~·Jo~ 3. R. Bruce Gill Wildlife Research Leader ��Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o _ Project No. W-153-R-4 Work Plan No. ~D~e~e~r~I~n~v~e~s~t~iQg~a~t~i~o~n~s Job No. Personnel: _ Development of Census Methods for Deer in Plains Riverbottom Habitats Period Covered: Author: Mammals Research July 1, 1990 ~,June 30, 1991 R. C. Kufeld D. Bowden, D. Younkin, J. Slater, B. Will, G. Ausmus, G. Everhart Abstract During January 3-9, 1991, 68 white-tailed deer were marked along the Arkansas River between Prowers, Colorado, and the Kansas State Line. Radiocollars and 2 numbered eartags were placed on 7 adult buc~, 32 adult does, and 5 doe fawns. Eleven ·adult bucks and 13 buck fawns r~ceived only eartags. ; These radJo-cq11ared:deer'vere located at about 2-week intervals· through Ju~y, '1991. Deer radio-corlared in·the South Platte Riverbottom during ,1987-89 weFe located at about 2-week intervals from July 1, 1990, through December 31, 1990. Deer in the Arkansas River between Prowers and Carlton, and the lower 12 Km of Big Sandy Creek, were counted and classified by sex and age 6 times by helicopter during January 21-24, 1991. Observers also recorded the number of radio-collared deer they saw during each count. Radio-collared deer were located by fixed-wing aircraft while. counts were in progress, so the number of radio-collared deer in the census area was known. A mean of 17% of radiocollared bucks and 43% of radio-collared does and fawns were seen. The population for the area flown 6 times was estimated within 38% with 95% confidence for bucks, within 12% for does and fawns, and within 14% for all deer. One count was made of the Arkansas River from John Martin Dam to the Kansas line plus the lower 12 km of Big Sandy Creek. Data suggest an estimated popUlation in that area of 806 white-tailed deer including 266 bucks and 540 does and fawns. Only 8 mule deer were counted in that river segment, which suggests that the Lower Arkansas Riverbottom habitat contains nearly all white-tailed deer. Buck/doe and fawn/doe ratios recorded during counts were believed to be too lo~, because (1) radio-collared does and fawns were found to be more observable than radio-collared bucks; and (2) the counts were made relatively late in the season when some bucks may have lost their antlers resulting in their being classified as does, and large size of fawns may have resulted in some fawns being classified as does. It is recommended that counts to determine population trends and sex and age ratios be made in December, when bucks still have their antlers and fawns are smaller, so both can be more easily distinguished from does. It is also recommended that the difference in obse!yability of bucks versus does an9.fawns be t~~en into consideration whe~ analyzing sex and age data, and when·adjusting aerial·deer count- data for unseen animals to project total population size~ ��11 DEVELOPMENT OF CENSUS METHODS FOR DEER IN PLAINS lUVEllBOTTOH HABITATS Roland C. Kufe1d P. N. OBJECTIVES 1. To determine seasonal movements and home range size of white-tailed and mule deer in plains riverbottom habitats. 2. To develop and test methods for estimating size of deer populations in plains riverbottom habitats. SEGMENT OBJECTIVE To determine seasonal movements and home range size of white-tailed and mule deer in plains riverbottom habitats. STUDY AREA The South Platte study area is the South Platte River extending from Platteville, Colorado, to the Nebraska State Line. It is dominated primarily by Cottonwoods (Populus sargentii) and ~~llows (Salix spp.). Th~s river .is. bordered mostly by agricultural lands, mainly ccznf'Le Lds'.. Some _stretches are bordered by rangelands dominated by mixed prairie ·or.sand sagebrush .(Artemisia £ili£olia) (Costello 1954). Streamflow in the South Platte is greatest of th~ plains rivers in eastern Colorado. The Arkansas study area is the Arkansas River extending from John Martin Dam to the Kansas State Line. The riverbottom supports some stands of cottonwood, but these are rapidly deteriorating due to lower river flows caused by upstream dam construction. The dominant vegetation along lower portions of the Arkansas River in Colorado is .sa1t cedar (Tamarix pentandra), which is replacing the cottonwoods (Snyder, 1988). Most of the riverbottom along the lower Arkansas River is bordered by agricultural lands. Deer populations along the South Platte River consist of both mule deer and-whitetails, but whitetails are the predominant species. The deer population within the lower Arkansas Riverbottom itself consists of almost all whitetails, but mule deer are common on the plains near the river. METHODS AND MATERIALS During January 3 through 8, 1991, white-tailed deer were captured and marked in the Arkansas Riverbottom between Prowers Bridge and the Kansas State Line, and along the lower 3 km of Big Sandy Creek. Some adult bucks, all adult does, and all female fawns received a radio-collar and 2 orange, numbered eartags. Radio collars placed on adult bucks were designed to expand and contract to allow for growth and expansion during the rut. Due to the limited number of expandable collars available, not all adult bucks captured were radio collared. Some adult bucks and all male fawns received only 2 orange, numbered eartags. Deer were captured in Clover traps (Clover 1956) baited with eazed eorn and alfalfa hay<--- �12 White-tailed and mule deer, radio-collared in the South Platte Riverbottom during January and February, 1987, 1988, and 1989 (Kufeld 1987, 1988, 1989), were located, primarily by aerial telemetry, at approximately 2-week intervals through December, 1990. White-tailed deer radio-collared in the Arkansas Riverbottom during January, 1991 were located, in the same manner, at approximately 2-week intervals through June, 1991. Deer locations were recorded by UTM coordinates and plotted on USGS 1:50000 scale maps. Vegetation type for each deer location was also recorded. During January 21 through 24, 1991, deer were counted 6 times by 2 observers (in addition to the pilot) in a Bell Soloy helicopter in the segment of the Arkansas between Prowers bridge and Carlton bridge, a distance of approximately 41 river km. The count area also included the lower 12 Km of Big Sandy Creek. This census area contained 98% of the radio-collared deer. Deer were counted once in the entire river segment from John Martin Dam to the Kansas State Line, a distance of approximately 99 km. plus the Big Sandy Creek section. Between John Martin Dam and Carlton bridge main roads, including state highways SO and 196 and Prowers County Road HR, parallel the river averaging about 1.5 km to the north and south o~ the river. The census area included the riparian habitat along the river, which averaged about 0.4 to 0.8 km in width, as well as agricultural lands between those roads. From Carlton bridge to the Kansas State Line other boundaries were used which included agricultural lands about 1 Km north and south of the riparian zone bordering the river. As the helicopter moved along the river it flew at treetop altitude and followed a zig-zag course from the outer edge of the riparian zone on one side of the river to the outer edge of t~e riparian zone on the other side. The adjacent agricultura~ lands in the censuS.area were ve~ open to vieli. Thus~ flights.·into ·the-ag~icultuJ:'alareas were made onl)i· to count and classify deer which were seen· from the hel~copter as it ~urned at the edge of the riparian zone. Each deer was counted and classified 'by species, sex and age, and a notation made if a deer was wearing a radiocollar. During each day that helicopter counts were conducted, a fixed-wing airplane flight was also made to locate all of the radio-collared deer. Thus, the number of radio-collared deer available to be seen in the census area while counts were in progress was known, and the proportion of radio-collared deer seen by. observers in the helicopter provided an estimate of the accuracy of their count. Unpaired-t tests were used to analyze sex and age ratio differences between counts. Differences were considered significant if P S 0.10. RESULTS Deer trapping and monitoring Sixty-eight white-tailed deer were marked along the Arkansas River between Prowers, Colorado, and the Kansas State Line and the lower 3 Km of Big Sandy Creek during the January 3 through January 9, 1991, period (Table 1). This included 18 adult bucks (7 radio collared and eartagged, and 11 only eartagged), 32 adult does (all radio collared and eartagged), 5 female fawns (all radio-collared and eart~gged), ~Ild 13 male fawns (all eartaggecl). No mule deer were c~ught'-auring the trapping operation. AnalysiS of data for �13 Tabla 1. Whit.a-t.ailad daar t. •••ed alema t.haArk__ aa lUvar bat._en Prowar., Colorado IIDdt.haKan.a. St.at.a Lin. Japuary 3. t.hroushJapuary 8, 1991.' Eart... As. whan Dat.a Radio-collar attachad 'numb.r Sax capturad capt.ur.d Captura locat.ion 148,140 Doa Adult. 1-3-91 Ro.ar. farm, O.S mi. E. of Prowar. Co. Rd. 13 149.210 Doa Yrl, 1-3-91 Rosar. farm, O.S mi. E. of Prewar. Co. Rd. 13 149.190 Doa Yrl, 1-3-91 Rosar. farm, O.S mi. E, of Prewar. Co. Rd. 13 149,422 Buck Yrl, 1-3-91 Rosar. farm, O.S mi, E. of Prewar. Co, Rd. 13 149,351 # Doa Yrl. 1-3-91 Bridsa farm, BiS Sandy Craak, 0.7S mi. H. of Hwy, 196 149,291 # Doa Adult. 1-3-91 Bridsa farm, BiS Sandy Craak, 0.7S mi. H. of Hwy. 196 148.060 Doa Yrl. 1-3-91 Bridsa farm, BiS Sandy Craak, 0.7S mi. H. of Bwy. 196 148.390 Doa Yrl. 1-3-91 Bridsa farm, BiS Sandy Craak, 0.7S mi. H. of Bwy. 196 148.040 Doa Adult. 1-3-91 Fayco.b farm, O.S mi. E. of Prowar. Co. Rd. 4 148.330 Doa Adult. 1-3-91 Fayco.b farm, O.S mi. E. of Prewar. Co. Rd. 4 Buck Fawn 1-3-91 Fayco.b farm, 0.2S mi. E. of Prewar. Co, Rd. S 148,1~0 Buck Adu-lt. 1-3-91 Cantar farm; 0.3 mi. E. of Prowar. Co. Rd. lS 149,431 Buck Adult. 1-3-91 Cantar farm, 0.3 mi. E. of Prewar. Co. Rd, lS 148,250 Doa Adult. 1-3-91 Cantar farm, 0.3 mi. E, of Prewar. Co. Rd. 16 Buck Fawn 1-3-91 Cant.arfarm, O.S mi. E. of Prewar. Co. Rd. 16 149,320 Doa Fawn 1-3-91 Cantar farm, 0.6 mi. E, of Prewar. Co, Rd. 16 Buck Fawn 1-3-91 C.nt.arfarm, 0.6 mi. E. of Prowar. Co, Rd, 16 Buck Fawn 1-3-91 McMillllDfarm, 0.4 mi. E. of Prowar. Co. Rd. 17 i 148,430 II Doa Adult. 1-3-91 McMillan farm, 0.4 mi. E. of Prewar. Co. Rd. 17 149,461 Buck Adult. 1-3-91 HcHillllDfarm, 0.4 mi. E. of Prewar. Co. Rd. 17 148,100 Buck Adult. 1-3-91 McMillllDfarm, 0.4 mi. E. of Prewar. Co. Rd. 17 148.130 Buck Adult. 1-3-91 Doranc.mp farm, O.S mi. W. of Kan.a. Stat.aLina Buck Yrl. 1-3-91 Dorancamp farm, O.S mi. W. of Kan.a. St.ataLina 148.290 $ Doa Fawn 1-4-91 Rosar. farm, O.S mi. E. of Prewar. Co. Rd. 13 Buck Fawn 1-3-91 Duvall farm, at.Prewa~. Co. Rd. 32 Buck Fawn 1-4-91 Rosar. farm, O.S mi. E. of Prewar. Co. Rd. 13 $ 149,770'" Doa Adult. 1-4-91 Rosar_ farm, O.S mi. E. of Prewar. Co. Rd., 13 Buck Fawn 1-4-91 Rosar_ farm, O.S mi. E. of Prewar. Co. Rd. 13 148,090 Buck ~ult 1-4-91 Bridsa farm, BiS SlIDdyCraak, 0.7S mi. H, of Bwy, 196 148,300 Doa Adult. 1-4-91 Bridsa farm, BiS SlIDdyCraak, 0.7S mi. H. of Bwy. 196 Doa, Yrl. 1-4-91 Fayco_b farm, O.S mi. E. of Prewar_ eo. Rd. 4 149.180 148,420 + 'Doa AdUlt 1-4-91 fayco_b f,!lrm, 0.2S mi. E., of Prewar. Co. Rd. S 149:200 + Doa Yrl. 1-4-91 Fayco_h farm, 0.2S mi.'E. of Prowar. Co. Rd. S 149,140 Doa Adult. 1-4-91 Cantar farm, 0.3 mi. E. of Prewer. Co. Rd,15' 148,400 ., Ooa Fawn 1-4-91 Cant.ar'farm,0.3 mi. E. of Prewar_ Co, Rd. 16 149,520 Doa Adult. 1-4-91 McMillan farm, 0.4 mi. E. of Prewar_ Co. Rd. 17 Buck Adult. 1-4-91 McMillllDfarm, 0.4 mi. E. of Prewar. Co. Rd. 17 Buck Yrl. 1-4-91 Dorancamp farm, O.S mi. ~. of Kan.a_ Stata Lina Buck Fawn 1-4-91 Dorancamp farm, O.S mi. W. of Kan.a. Stat.aLina Doa Adult 1-S-91 Rosar_ farm, O.S mi. E. of Prewar_ Co. Rd. 13 148,200 149,020 Doa Adult. 1-S-91 Rosar_ farm. 0.5 mi. E. of Prewar. Co. Rd. 13 149,370 Doa Adult 1-S-91 Bridaa farm, BiS Sandy Craak, 0.7S mi. H, of Bwy, 196 Buck Fawn 1-S-91 Fayco_h farm, O.S mi. E. of Prewar. Co. Rd. 4 & Buck Fawn 1-S-91 Fayco_h farm, O.S mi. E. of Prewar_ Co. Rd. 4 & Doa Adult 1-S-91 Fayco_h farm, O.S mi. E. of Prewar. Co. Rd. 4 148.3S0 Doa Adult. 1-S-91 Fayco_h farm, O.S mi. E. of Prewar_ Co. Rd. 4 148,410 148,270 Doa Adult. 1-S-91 Fayco_h farm, 0.2S mi. E. of Prewar. Co. Rd. 5 Doa Adult. 1-S-91 Grasmick farm, 0.7S mi. E. of Prewar. Co. Rd. 10 149.150 Buck Adult. 1-S-91 Cantar farm. O.S mi. E. of Prewar. Co. Rd. lS Buck Fawn 1-5-91 Cant.arfarm, 0.6 mi. E. of Prewar_ Co. Rd. 16 Doa Adult. 1-5-91 McMillan farm, 0.4 mi. E. of Prewar. Co. Rd. 17 148.240 148,340 Doa Fawn 1-6-91 Fayco_h farm, O.S mi, E. of Prewar. Co, Rd. 4 Doa Adult 1-6-91 Fayco_h farm, 0.2S mi. ,E. of Prowar. Co. Rd. 5 149.230 Buck Adult 1-6-91 Cant.arfarm, O.S mi. E. of Prewar_ Co. Rd, lS Doa Adult. 1-6-91 Cant.arfarm, O,S mi. E. of Prewar. Co. Rd. 16 149,380 * Buck Fawn 1-7-91 Rosar. farm, O.S mi. E. of Prewar. Co. Rd. 13 148.450 Doa Adult 1-7-91 Rosar. farm, O.S mi. E. of Prewar. Co. Rd. 13 149.110 Doa Fawn 1-7-91 Bridaa farm, BiS Sandy Craak, 0.7S mi. H. of Bwy. 196 Doa Yrl. 1-7-91 Fayco_h farm, O.S mi. E. of Prewar. Co. Rd. 4 149.240 Buck Yrl. 1-7-91 Fayco_b farm, 0.2S mi. E. of Prewars Co. Rd. 5 Buck Adult 1-7-91 McHillllDfarm, 0.4 mi. E. of Prewar. Co. Rd. 17 Buck Adult 1-7-91 Cantar farm, O.S mi. E. of Prewars Co. Rd. lS Buck Adult. 1-8-91 Dorancamp farm, O.S mi. W. of Kan.a. Stat.aLina 149.170 Doa Adult. 1-8-91 Fayco.h farm, O.S mi. E. of Prowars Co. Rd. 4 Buck Fawn 1-8-91 Fayco.b farm, 0.2S mi, E, of Prewar. Co, Rd. S Buck Yrl. 1-8-91 Bridsa farm, BiS Sandy Craak. 0.7S mi. H. of Bwy. 196 149,220 Doa Adult. 1-8-91 Bridaa farm, BiS Sandy Craak. 0.7S mi. H, of Bwy. 196 Buck YrL 1-8-91-" Bridsa farm, Bis Sandy Creak, 'O,7S m1. fL'-OfBwy, 196 in tba ._a 'Pair_ of daar da.ianat.adwit.ht.hafollowins .ymbols wara t.rappador ratrappad t.osat.bar trap and may ba ralatad a. mot.har- off.prins, or a_ twin.: #, ., $, ",'+, *, &, 69 101 128 129 130 131 132 133 134 13S 136 137 138 139 140 141 142 143 144 14S 146 148 149 lS0 lS4 lSS 179 180 181 182 183 184 18S 186 187 188 189 190 191 192 193 194 19S 196 197 198 199 200 201 202 203 204 20S 206 207 208 209 210 211 212 213 214 21S 216 217 ,218 219 220 ---r- �14 movements, home range size, and habitat use will be presented in a future report when periodic monitoring of deer is completed. Deer Counts Presence of snow cover is usually considered a prerequisite to conducting aerial counts of deer. Adequate snow cover in Southeastern Colorado is relatively rare and may occur only once in several years. Thus, deer counts can rarely be scheduled when snow cover is adequate. Therefore, the decision was made to fly during average winter conditions which likely meant inadequate or no snow cover. Du~ing the counts, snow cover varied from almost none most of the time to as much as 100% during part of one day. The increased snow cover did not appear to affect the observabi1ity of deer. Percentages of radio-collared deer in the count area were 98% on 3 counts, 95% on 2 counts, and 93% on 1 count. The proportion of radio-collared deer seen was relatively low, averaging less than 40% on the 6 counts (Table 2). Kufe1d (1989) reported that an average of 69% of the radio-collared, white-tailed deer were seen on 3 similar counts of deer in the South Platte Riverbottom between Platteville, Colorado, and the Nebraska State Line. Does and fawns were much more observable than bucks (Table 2). The number of bucks and does and fawns recorded during a count was adjusted upward, based on the percent of radio-collared deer seen during' that count, to provide an estimat~ of the total deer population in the area censused (Table 2). Relative precision of population estimates is based on adjust~d total deer seen during the 6 counts . .~e popu~atio"!lwas estimated wi~hin 38% with 95% confidence for bucks, within 12% for does and fawns and within 14% for all deer. Table 2. White-tailed deer seen on January 21-24, 1991, helicopter counts of deer in the Arkansas Riverbottom between Prowers Bridge and Carlton Bridge. % Q{ I~dio-coll~I§ Does & fawn§ Fl.ight ~ucks 33% 56% 1 44 0 2 3 17 33 46 4 17 17 43 5 6 12 II x SE seen All deer 52% 38 31 41 39 aa Iotal de~[ seen Does & Bucks fawns 30 150 23 107 83 23 110 22 18 103 111 22 Adju§ted total Does & Bucks· fawns 268 91 230 243 135 252 239 129 240 106 129 ill deer1 deer 359 473 387 368 346 446 17% 43% 39% 137 260 397 4% 4% 3% 20 12 21 :Adjusted upward for the percent of radio-collars seen.' Example: 17% of total buck radio-collars seen and 23 total bucks seen: 23/.17 - 135 adjusted bucks seen. On flight 3, which provided a count of deer in all river segments from John ·Martin Dam to the Kansas Line plus-the lower 12 km of-Big Sandy Creek, 218 white-tailed deer (38 bucks and 180 does and fawns) and 14.3% of the.radio- ., �15 c~llared bucks and 33.3% of the radio-collared does and fawns were observed. The estimated adjusted total population of white-tailed deer for this area is 806 deer including 266 bucks and 540 does and fawns. Only 8 mule deer were counted during flight 3 and none were counted during the 6 repetitive flights, so no population estimate for mule deer is available. However, it appears safe to suggest that the mule deer population in the riverbottom downstream from John.Martin Dam to Kansas and in the lower 12 km of Big Sandy Creek is very low. Although mule deer were not seen in the riverbottom itself they were frequently seen in upland agricultural lands and rangelands within 2 Km or so of the study area. Deer Sex and A&e Classification ~ite-tai1ed deer sex and age ratios in all river segments (Flight 3) were 32 bucks/lOO does and 54 fawns/lOO does. These are similar to mean sex and age ratios for the 6 counts between Prowers Bridge and Carlton Bridge (Table 3). No significant differences in buck/doe ratios occurred between any of the 6 counts. No significant differences in fawn/doe ratios occurred between counts 1,2,3,4, or 6, but fawn/doe ratios on count 5 were significantly higher than those on the other counts (Table 3). Estimating precision for buck/doe ratios was better than for fawn/doe ratios. Based on 6 counts the mean buck/doe' ratio was estimated within 15% of the mean with 95% confidence compared to-28% of the mean for fawn/doe ratios. Table 3. Sex and age ratios for white-tailed deer seen on January 21-24, 1991, helicopter-counts of deer in the Arkansas-Riverbottom between Prow:ers Brigge and Carlton Bridge. Flight Bucks/laO Does Fawns/lOO- Does 1 2 3 4 5 6 x SE 29 31 41 30 31 42 II 43 322 49 37 48 49 74 5 DISCUSSION The Arkansas Riverbottom and lower Big Sandy Creek in eastern Colorado present a rather unique situation for aerial censusing of deer in that the area is very long, narrow, and winding. Because of its shape the area is not suited for implementation of a randomized helicopter quadrat census system (Kufeld et al. 1980), or an aerial line transect system (Burnham et al. 1980, ~ite et al. 1989). Thus, it was deemed more efficient to census the entire area. DeYoung (1985), Beasom et a1. (1986), Bartmann et al. (1986), and Kufeld (1989) have shown that during aerial counts of white-tailed and mule deer somewhat fewer than 100% of the deer present are actually seen and recorded. Beasom et al. (1986) reported accuracy of aerial counts for whitetails was unaffected by sample intensity, but precision increas~d with percent of the area sampled. Since we sampled- the--ent1re-area of interest, ftndings of· - Beasom et a1. (1986) suggest the only way to increase our precision is with �16 replicate counts. constraints. The number of replicate counts is subject to economic Sightabi1ity of animals during aerial counts is influenced by factors such as speed, height above ground, transect width, observers, group size and vegetation cover (Caughley et al. 1976, Barnes et al. 1986, Samuel et al. 19.87). Aerial deer counts in plains riverbottom habitats should be designed and conducted with these factors in mind. For example, the helicopter should fly at a speed of from 56-72 km/hr, and altitude of about 30 m. Zig-zag paths taken by the helicopter across the census area should be sufficiently narrow that there is good visibility of the area between subsequent passes. Observers should be experienced and familiar with the area. Counts should be conducted only in winter when leaves are gone from deciduous trees and shrubs. Kufeld (1989) suggested that, when censusing deer in the South Platte Riverbottom in northeastern Colorado, counts should be conducted only when there is 100% snow cover. That should not be a restriction when censusing deer in the lower Arkansas Riverbottom, because the relatively rare occurrence of adequate snow cover in that area could preclude deer counting for several years at a time. Even though snow cover might increase the number of deer observed, a realistic population estimate can be obtained without snow cover as long as data are available (such as provided by this study) to show the mean proportion of deer observed when snow is absent. The relatively low proportion of radio-collared deer seen on flights of the Arkansas River compared to flights of the South Platte may have been influenced to some extent by the presence of snow cover on the South Platte, but was more likely due to a difference in vegetation. It is more difficult to see deer in the thick salt cedar vegetation along-the lower Arkansas River than it is in the more open Cotto~wood typ~ along the South :Platte: Accuracy of deer sex and age ratio data is dependent upon validity of~the . assumption that deer in all sex and age categories are equally observable. Leon et al. (1987) found no sex or age bias in the composition of white-tailed deer encountered during helicopter counts in Texas. This is contrary, however, to our finding that radio-collared does and fawns were more observable than instrumented bucks. Lower observability of radio-collared bucks casts doubt on the accuracy of our recorded buck/doe ratios even though differences among the 6.counts in buck/doe ratios were not significant. A higher ratio than 32 bucks/lOO does should have resulted if bucks and does were equally observable. Fur~her evidence that the buck/doe ratio observed on counts may be too low is that 56 adult bucks/lOO does were caught during the trapping operation, and it has been the author's experience that adult whitetail bucks are usually much harder to catch than does.· The suspected relatively low buck/doe ratios on counts could have been due to a tendency of bucks to be more wary, but could also have been at least partly due to the time of year counts were made. Since counts could not begin until trapping was completed, these counts were made rather late in the year for accurate classification by sex and age. Some bucks may have lost their antlers which would have made it difficult to distinguish bucks from adult does. This was not a problem with radio-collared bucks, however, because they had collar configurations which identified them as bucks. Higher variability in buck/doe ratios compared to fawn/doe ratios were reported by Bowden et a1. (1984), and Kufeld (1989). However, during our 6 flights of the lower Arkansas River we observed lower variability and higher estimating preci"sion .fo'r -buck/do_eratios. The higher variability of -fawn/doe ratios was largely due--to the significantly higher ratio on the 5th count. If that count is deleted standard errors for fawn/doe ratios on the remaining 5 �17 counts are slightly lower than for buck doe ratios. Because the counts were made relatively late in the year it was difficult to distinguish fawns from adult does due to their size. Thus, reported fawn/doe ratios, like buck/doe ratios, may also be too low. These findings give rise to the following recommendations. RECOMMENDATIONS It is recommended that counts to determine population trends" and sex and age ratios be made in December when bucks still have their antlers and fawns are smaller, so both can be more easily distinguished from does. It is also recommended that the difference in observability of bucks versus does and fawns be taken into consideration when analyzing sex and age data, and when adjusting aerial deer count data for unseen animals to project total population size. LITERATURE CITED Barnes, A. G.", G. T. E. Hill, and G. R. Wilson. 1986. Correcting for incomplete sightability in aerial surveys of Kangaroos. Aust. Wildl. Res. 13:339-348. Bartmann, R. M., L. H. Carpenter,"R. A. Garrott, and D. C. Bowden. 1986. Accuracy "of he.licopter ccuncs of mule" deer in pinyon-j.uniper woodland. Wildl. Soc. Bull. 14:356-363.' Beasom, S. L., F. G. Leon III, and D. R. Synatzske. 1986. Accuracy and precision of counting white-tailed deer with helicppters at different sampling intensities. Wildl. Soc. Bull. 14:364-368. Bowden, D. C., A. E. Anderson, and D. E. Medin. 1984. Sampling plans for mule deer sex and age ratios. J. Wildl. Manage. 48:500-509. Burnham, K. P., D. R. Anderson, and J. L. Laake. 1980. Estimation of density from line transect sampling of biological populations. Wildl. Monogr. 72. 202pp. Caughley, G., R." Sinclair, and D. Scott-Kemmis. survey. J. Wild1. Manage. 40: 290- 300. Clover, M. R. 201. 1956. Single-gate deer trap. 1976, Experiments in aerial Calif. Fish and Game 42:199- Costello, D. F. 1954. Vegetation zones in Colorado. Pages iii-x in H, D. Harrington, ed. Manual of the plants of Colorado. Sage Books, Denver, CO. DeYoung, C. A. 1985. Accuracy of helicopter surveys of deer in south Texas. Wildl. Soc. Bull. 13:146-149. Kufeld, R. C. 1987. Development of census methods for deer in plains . riverbottom habitats-:- C-olo: Div. Wild!., Wildl Res. Rep. July: ]:-1".;;21. �18 Kufe1d, R. C. 1988. Development of census methods for deer in plains riverbottom habitats. Colo. Div. Wi1d1., Wildl. Res. Rep. Ju1y:11-2l. Kufeld, R. C. 1989. Development of census methods for deer in plains riverbottom habitats. Colo. Div. Wi1d1., Wi1d1. Res. Rep. Ju1y:11-19. Kufe1d, R. C., J. H. 01terman, and D. C. Bowden. 1980. A helicopter quadrat census for mule deer on Uncompahgre Plateau, Colorado. J. Wi1d1. Manage. 44:632-639. Leon, F. G., III, C. A. DeYoung, and S. L. Beasom. 1987. Bias in age and sex composition of white-tailed deer observed from helicopters. Wi1d1. Soc. Bull. 15:426-429. Samuel, M. D., E. o. Garton, M. W. Schlegel, and R. G. Carson. 1987. Visibility bias during aerial surveys of elk in northcentral Idaho. Wi1d1. Manage. 51:622-630. Snyder, W. D. 1988. Dynamics of cottonwood regeneration. Wi1d1. Res. Rep. Apri1:327:393. J. Colo. Div. Wi1d1., White, G. C., R. M. Bartmann, L. H. Carpenter, and R. A. Garrott. 1989. Evaluation of aerial line transects for estimating mule deer densities. J. Wi1dl. Manage. 53:625-635. Prepared by ·~c%/dd Roland C. Kufe1d Wildlife Researcher C. �19 . Colorado Division of Wildlife Wildlife Research Report July 1991 JOB FINAL REPORT State of ~C~o~l~o~r~a~d~o _ Project No. W-153-R-4 Deer Investigations Work Plan No. Job No. 8 Period Covered: Author: Mammals Research Accuracy of mule and white-tailed deer harvest reported by deer hunters on mailed questionnaire surveys. July I, 1990 - June 30, 1991 R. C. Kufeld Personnel: R. C. Kufeld, H. D. Riffel, D. C. Bowden, Numerous Northeast and Southeast Region field personnel . Abstract Successful dee-rhUnt~-rs who -were checked in the field with their deer during the 1990'plains deer seasons were sent mailed questionnaires, and thejr .answers compared with their known kill to determine the degree of accuracy with which hunters report the species, sex, and age of their deer ~n the annual Colorado Division of Wildlife hunter questionnaire survey. Species was reported correctly by 96% of hunters who killed whitetails compared with 85% of hunters who killed mule deer. All hunters reported sex of adult deer correctly, but only 58% of fawns killed were reported as fawns. The remaining 42% were reported as adult does. It is recommended that harvest projections based on questionnaire data be adjusted to allow for reporting error before using them in population models or in making management decisions. During the plains deer seasons (October and December), hunter questionnaire data (adjusted for hunter error in reporting deer by species) show that mule and white-tailed deer made up 83% and 17% of the harvest in'1989, and 81% and 19% in 1990 in all plainS game management units. ��21 ACCURACY OF MULE AND WHITE-TAILED DEER HARVEST REPOR.TED BY DEER HUNTERS ON HAILED QUESTIONnAIRE SURVEYS R.oland C. Kufeld P. N. OBJECTIVES To determine the degree of accuracy with which successful plains deer hunters report the species, sex and age of their kill on the annual Colorado Division of Wildlife hunter questionnaire survey. SEGMENT OBJECTIVE Same as P. N. Objective. STUDY .AREA. All game management units in eastern Colorado where plains deer seasons were scheduled ~uring October and December of 1990. QUODS AND MATERIALS Colorado: Division of Wildlife District Wildlife M~nagers and other DOW f'LeLd persopnel stationed in areas where plains deer seasons were scheduled~were _ asked to participate in collection of field data. Data collection was duringthe course.of·their regular law enforcement activities when patrolling the October and December, 1990, plains deer seasons. When a successful deer hunter was encountered the officer recorded the hunter's name, date of birth, and hunting license number on his regular hunter contact form, and the species, sex and age (whether fawn or older) of the deer. If the hunter asked the officer what species of deer they had killed, the officer, before answering, asked the hunter what species they thought they had killed. Then that information plus the actual species was recorded on the contact form. At the end of the plains deer seasons, wildlife research personnel reviewed the contact forms and extracted the pertinent contact information. Since all plains deer licenses are specified licenses, names and addresses of all license holders are available prior to beginning of the season, and the annual, random, questionnaire survey sample is drawn before the season starts. A questionnaire was sent to each successful deer hunter who was contacted in the field. Only about 55% of deer hunters are sampled during the annual questionnaire survey. Thus, successful, field contacted deer hunters not selected in the annual questionnaire survey were sampled in a separate mailing using identical questionnaire forms. Questionnaire responses from all field contacted plains deer hunters were compared with field contact forms to·determine the proportion of questionnaires on which species, sex, and age (fawn or older) of deer was .reported c;:orr~ctlyand incorrectly. �22 Deer hunters in plains game management units have been surveyed, annually, by mailed questionnaire for a number of years. During 1989 and 1990, hunters were asked to report their deer kill by species. To date, the annual Colorado Division of Wildlife B~g Game Harvest Report has reported the number of deer killed, but the harvest was not separated by species. The 1989 and 1990 plains deer hunter questionnaire data were further analyzed a~ part of this study to provide an estimate of plains deer harvest of mule and white-tailed deer in each game management unit. Harvest estimates were adjusted for hunter error (error data acquired during this study) in reporting species of . deer harvested on mailed questionnaires. RESULTS AND DISCUSSION Only 85 usable questionnaire forms were received from hunters who were checked in the field with their deer by DOW personnel. There are at least 2 reasons for the low sample size.. (1) Most plains deer hunters return home each day following their hunt. Thus, unlike deer hunters in the mountains, relatively few stay in camps for several days at a time where they are available for contact by law enforcement personnel. Their tendency to return home after each day's hunt and the extensive road system on the plains 'reduces the likelihood that a successful deer hunter, 'accompanied by his or her kill, will be encountered by an officer. (2) Not all successful deer hunters contacted -returned their questionnaires even though up to 2 fo110wup questionnaires were' sent to nonrespondents. The proportion, of-questionnaires returned by hunters, known to have been 'suc;cessfu1,was 78%. Hunters who harvested a white-tailed deer (Odocoileus virg~nianus) had a higher rate of repoiting the speci~s correctly tha~ did hunters who harvested a mule deer (Odocoileus hemionus). More mule deer ,hunters tended to report their deer as a white-tail (Table 1). All hunters who harvested an adult buck or an adult doe reported the age and sex correctly (Table 1). Rasmussen and Palmateer (1984) also observed a low error rate of only 1.3% in reporting sex of adults, but their questionnaires on which sex was reported erroneously showed a tendency of hunters to report adult females as adult males. In our study, although the sample size is low, a large proportion of fawns of both sexes harvested were reported as adult does (Table 1). These findings have some important implications for management uses of harvest data derived from the hunter questionnaire. They suggest that the harvest of white-tailed deer projected from'questionnaire data may be too high and projected harvest of mule deer may be too low. However, harvest projections of each species could be adjusted according to the percentages reported in Table 1. The questionnaire data also suggest that, since fawns are frequently reported as adults, estimates of adult doe harvest from questionnaire surveys, may be too high by a substantial percentage, and estimates of fawn harvest may be too low. If fawn/doe ratios in the harvest, based on questionnaire data, are used in population models without adjustment for incorrect reporting of age of antler1ess animals, substantial error could occur in projected population estimates. . �23 Table 1. Percentage of deer, checked by Division of Wildlife personnel during October and December, 1990 plains deer season, that were reported correctly and incorrectly by species, sex, and age on mailed hunter survey questionnaires. % Reported Actual No. of Reported Correctly Incorrectly Deer Deer Killed Deer Killed Whitetail Mule Deer 50 96 _2. 4 52 Mule Deer Mule Deer Whitetail 28 85 _2 15 33 Adult Buck Adult Buck 36 100 0 Adult Doe Adult Doe 30 100 0 Fawn Buck Fawn Buck Adult Doe 5 63 37 .1 8 Fawn Doe Fawn Doe Adult Doe 2 50 50 .2. 4 Fawn (all) Fawn Adult 7 58 _2 42 -12 Sinc~mailed questionnaire responses from hunters with known 15% of hunters who killed a mule deer tend to report it as a of hunters who killed a whitetail tend to report it as a ~le the following procedure was used to adjust the 1989 and 1990 hunter questionnaire data for hunter error in reporting deer kills show that whitetail and 4% deer (Table 1), plains deer kill by species: Where: Reported harvest of -mule deer x 0.15 - A And: Reported harvest of mule deer x 0.04 - B Then: Reported harvest of mule deer - B + A - Adjusted harvest of mule deer. And: Reported harvest of whiteotailed deer - A + B - Adjusted harvest of white-tailed deer. Total adjusted harvest of both species must equal total reported harvest. Thus, if adjusted harvest of one species is more than the total reported harvest of both, the adjusted harvest of that species becomes equal to the total reported harvest of both, and the adjusted harvest of the other species is O. For example, this could happen if the ~eported harvest of mule deer was very high and reported harvest of whitetails very low. Adjustments were made only in certain game management units which had relatively large portions of white-tailed dee'r in t_lleharvest during 1989:-~Q (Table 2). �24 Tmb 2. Barve.t of mul. and whit.-t.iled d••r durins 1989 and 1990 Octob.r and D.cemb.r 9 9 llDi~ t2!all st•• , 87 88 89 90 91* 92* 93* 94* 47 41 9S* 78 56 20 41 84 92 51 47 71 15 141 527 39 i78 52 75 65 951* 96* 97 98 99 100 101 102* 103* 104 lOS 106 107* 109" 110 111 112 113* 114 115* 116 117 118"' 119 120 121 122" 123* 124* 125* 126* 127* 128* 129* 130'" 13Z'" 133 134 13S 136 137 138* 139'" 141 142 143 144 145"' 146* 147 Total 3S 21 lS 16 6S 4S 2S 26 71 ·29 18 9 13. 30 ·14 6 64 4 40 83 14 49 39 12 . 13 41 7 2 8 23 11 7 39 S 29 SO 0 2 31 ___a 2733 !:!!!UI~aU.1 4 4 2 1 47 26 0 23 S 21 82 0 S S 3 1 21 22 2 44 0 12 lS 6 2 3 2 S 8 4 0 . 14 0 1 0 S 11 4 25 11. 17 7 1!1 11 31 0 1 1 1 0 3 9 0 0 0 0 6 10 _0 558 pl.ina rifl. d•• r 990 Iotal ~1. 12•• , Wh!t!taH!I! Total Sl 4S 39 42 34 29 7 17 43 1 0 1 3 75 36 1 23 0 29 89 4 9 1 7 3 21 29 7 40 42 37 22 62 42 6S 68 83 77 102 41 89 97 54 48 92 37 143 571 39 190 67 81 67 28 28 76 37 22 9 27 .30 15 . S6 78 S7 17 36 81 104 48 37 82 7 141 521 66 186 42 104 49 23 26 '78 39 31 9 19 62 lS 6 11 69 15 44 108 S9 2S 66 46 27 24 72 7 '3 9 24 11 10 48 12 19 72 32 S6 39 9 31 S6 0 8 41 __ 2 9 2 3 21 4 27 32 0 31 84 3 12 27 __ 0 3291 2876 S 29 SO S2 0 6 7 5 3 0 2 10 0 0 0 8 4 0 1 6 7 8 41 20 31 9 9 6 28 2 0 0 0 0 S 12 0 0 7 0 12 14 _0 644 3S 32 82 53 44 79 78 86 106 40 90 105 S5 40 103 36 148 573 66 192 59 109 S2 23 28 88 39 31 9 ., 27 .66 lS 1"2 65 19 27 113 52 87 48 18 37 84 11 2 3 21 4 32 44 0 31 91 3 24 41 __ 0 3540 * Th ••• sam. manas.aent unit. had r.lativ.ly lars. portion. of whit.-tail.d d ••r in the harv ••t durins 198990. Barv •• t ••timate. in the •• unit. have bean adju.ted fo~ e~ror in reportina .peci.. of deer harve.t.d on mailed qu •• tionair ••• _.DUring the plains deer seasons (October and'December)., hunter questionnaire d&ta show that mule and white~tailed deer made up 83% and 17% of the harvest �25 in 1989, and 81% and 19% in 1990 (Table 2). Both species of deer occur throughout the eastern Colorado plains. Whitetails occur mostly in or near riparian h~bitat along rivers and creeks, and around lakes and ponds. Game management units where high harvest of whitetails occurred (Table 2) were those along the South Platte, Arkansas, and South Republican Rivers, Fountain Creek, and Big Sandy Creek, as well as tributaries of all of those streams. Mule deer occur in those same habitats as well as being found far out on the plains away from riparian habitat. Mule deer have occurred on the plains of eastern Colorado since before the first white men came to the state. According to Hunter (1949) there were no white-tailed deer in Colorado in the late 1940s. There is evidence that the whitetail population in eastern Colorado has grown at a relatively rapid rate (Kufeld 1989). If white-tailed deer popUlation trends continue upward_on the plains of eastern Colorado, competition between whitetails and mule deer could possibly result in a negative impact on mule deer, at least in riparian habitats where both species occur. A need may arise for separate management of white-tailed and mule deer populations in plains game management units in order to keep the 2 populations in balance. Also, as a result of the increasing whitetail population, deer damage to irrigated agricultural fields, which are commonly located near riparian habitat favored by whitetails, may become more of a problem. Deer popUlation control for purposes of alleviating damage to such fields may be more efficiently accomplished if white-tailed and mule deer populations are managed separately. Colorado deer hunting licenses have traditionally been issued with no specification as to species of deer that can be taken. " Manipulation of the population level of one deer species through hunting without changing the population level of the other species would be possible only by issuing deer licenses which specify speci-es of deer to be taken. This "would require "tnat hunee rs be "able to idei}.tify deer by species in the field. _ -" Data in Table 1 suggests that most hunters are able to identify mule and white-tailed deer. -The minority of hunters who cannot identify them correctly could probably be educated by including pictures of identifying characteristics in the license application brochure and with the specified license when issued. LITERATURE CITED Hunter, G. N. 1948. History of white-tail"ed deer of Colorado. and Fish Dept., Denver. 10pp. Colorado Game Kufeld, R. C. 1989. Development of census metho~s for deer in plains riverbottom habitats. Colo. Div. Wildl. Wildl. Res. Rep. July 1:11-17. Rasmussen, G. P., and J. R. Palmateer. 1984. Hunter error in reporting the sex of deer. New York Fish and Game Jour. 31:138-145. Prep!,"ed by ~ .. - . C .Ro1a 9~ C. K fela Wi1d1i£e Researcher ��Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~ _ Project No. W-153-R-4 Mammals Research Deer Investigations Work Plan No. Job No. Period Covered: Author: Compensatory Effects of Harvest in a Mul~ Deer Population 5 July 1, 1990 - June 30, 1991 R. M. Bartmann, G. C. White Personnel: A. W. Alldredge, L. H. Carpenter, K. C. Crane, W. I. Dean, W. Devergie, B. L. Dupire, D. J. Freddy, J. Frothingham, J. L. Godbey, V. K. Graham, J. P. Gray; R. Harthan, E. K. Jones,- J. D. Madison, J. E. Morris, D. G. Saltz, C. L. Vardaman, M. A. Warner, and numerous others from the Colorado Division of Wildlife and Colorado State University. Abstract. Two aerial line transect surveys were flown on the Ridge study area to try and detect the extent of deer reduction on the treatment unit during the December hunting season. The estimated decline from 57 to 32 deerfkm2 was about 40% greater than what could be accounted for by the estimated harvest. Based on other data, the deer population on the ·treatment unit is still considered above the target level of 40fkm2. Poor trapping conditions allowed only 71 fawns to be radio collared--far below the goal of 120 fawns. Estimated fawn survival rates were 0.320 (SE - 0.090) and 0.274 (SE - 0.078) on control and treatment units, respectively. Twenty-seven does were radio collared bringing the totals to 39 and 42 on the control and treatment units, respectively. Estimated adult survival to IS June was 0.949 (SE - 0.035) and 0.853 (SE - 0.(61) on the same respective units. All adult deaths except for 1 on each unit were hunting related. Fawn:doe ratios were estimated before (control 79:100, treatment 81:100) and after (control 67:100, treatment 64:100) the late season. Neither the differences between units for each survey, nor within units between the 2 surveys were significant (~> 0.050). The harvest estimate for the late season was 392 of which 32% were fawns. Male fawns continued to be larger than females in weight, total body length, and left hind foot length (~< 0.001), but there were no differences between study units (~~ 0.239). The estimated age structures of does harvested during the 1990 regular and late seasons were different (~- 0.050). As in 1989, more yearlings and fewer old does (>7 years old) were harvested during the regular seasons. To date, no meaningful differences have been found in body size parameters of yearling and adult does between the 2 study units. Som~ ~if.fere11:~es J,n_antler and body _size c;haracteristics.were. 4!!t;ec.ted with year+ing bucks, but sample sizes were small (1-9). ��29 COMPENSATORY EFFECTS OF HARVEST IN A MULE DEER POPULATION Richard M. Bartmann and Gary C. White P. N. OBJECTIVES 1. Increase the winter survival rate of mule deer fawns by lowering total deer density to reduce competition for for~ge during winter. 2. Increase the harvest rate of deer througn increased productivity of adult does and decreased natural mortality of fawns resulting from closer alignment of population size with carrying capacity. 3. Evaluate deer harvest rates and population response on a DAU basis resulting from bucks-only hunting and from buck hunting with additional antlerless permits designed for annual removal of 20% of the adult female population. SEGMENT OBJECTIVES 1. Reduce the winter population of mule geer on the Ridge treatment area to a density <40jkm2 and maintain' t?e density. for at least 3 y~ars~ 2. Estimate winter survival rates of fawns on control ~nd treatment.a.reas. 3. Estimate annual survival rates of adult females. 4. Estimate annual survival rates of adult ·males. 5. Estimate productivity 'of deer on control and treatment areas. 6. Estimate harvest rates of bucks, does, and fawns on control and treatment areas. 7. Estimate condition of fawns on control and treatment areas. 8. Estimate age structure of adult females on the treatment area and condition of yearling females on control and treatment areas. 9. Estimate age structure of adult males and condition of yearling males on control and treatment areas. METHODS Most methods remain the same as previously reported (Bartmann 1990). The main exception is the use of the staggered-entry Kaplan-Meier estimator (Kaplan and Meier 1958, Pollock et al. 1989) to estimate fawn survival rates instead of .the ..binomial e.s.timator. Unlike ..the binomial.es1:_imator, the Kaplan..-Me.ier._ estimator uses censored animals (those with failed radios or with collars that �30 dropped off prematurely) to calculate annual survival rates. For data with no censored observations, Kaplan-Meier and binomial estimates are identical. The past few years, the number of censored animals has increased. During the 1989-90 winter, a problem occurred with premature collar drop-offs beginning in mid-March. This past winter, there was a greater than expected number of radio failures. When such problems occur later in the winter, a considerable amount of information can be lost unless these animals are included in survival rate estimates. The exception to the use of the Kaplan-Meier estimator is when multifactor analyses are used for hypothesis testing. These situations require that fawn survival data be treated as a binomial process. RESULTS AND DISCUSSION Population Reduction From 1985 to 1988, deer density estimates from helicopter line transect surveys on control and trea~ent areas fluctuated around 70~ (Fig. 1). The removal of an estimated 451 deer by hunting in December 1989 was not reflected in line transect results that year as deer density on the control area, 47jkm2, was lower than on the treatment area, 66~. In 1990, 2 line transect surveys were flown, 1 immediately before and the other immediately after· the experimental December late season, to see if ~e could detect an imm.ediate·effect·of·the harvest on deer. density. Pre-season ..dens icy estimates seemed- reasonable.·.67 and 57 deerjkm2 on the control and treatment areas, respectively. An estimated_392 deer were harvested during the 1990 late season, but the post-season density estimate of 32 deerjkm2 indicated a population reduction about 40% greater. The predicted density was still well within the 95% confidence interval because of high variability. We presume this was due, in part, to observing fewer groups as a result of the lowered density. In the future, additional transects will have to be flown to increase the number of groups seen. Unexpectedly, density on the control area increased 27% to 85 deer~ and was significantly higher than on the treatment area (l < 0.05) despite wide confidence intervals. This increase was not explained by movement of animals because radio-collared deer remained on .their respective areas. The use of different observers for the 2 surveys was a potential source of bias, but we had no way to evaluate it. Based on other data, we believe true deer density on the treatment area is still above the target level of 40jkm2. Accordingly, the number of late season licenses for the December, 1991, season (350) will only be slightly less than in 1990 (400). Fawn Suryi val Deer were trapped from November 12-30, 1990. Extremely poor trapping conditions resulted in only 71 fawns being radio collared; slightly more than half the l2a fawns desired. Contributing to the problem was the limited trapping period that was constrained by the end of the third regular deer season and the start of the late season. Trapping may be mo~e_difficult in 1991-,-even with more··conducive weathe-r conditions, because. the number. of fawns �31 to be radio collared increases to 160, and there will be fewer deer available on the treatment area. Estimated fawn survival on control and treatment areas in 1989-90 was greater than 50% for only the second time (survival was 0.537 on the control unit in 1985-86) since collection of survival data began on the Ridge study area in 1982-83 (Table 1). That winter was quite mild, but there haye been similar winters without such high survival. These higher survival rates will decrease the chance of detecting differences in survival between the 2 areas over time because of the increased variation added to the survival time series. Table 1. Survival rate estimates (i) for radio-collared mule deer fawns on control and treatment units of the Ridge study area in Piceance Basin, Colorado, from time of collaring in November and December until the following 15 June 1982-83 through 1990-91. Winter 1982-83 1983-84 1984-85 1985-86 1986-87 1987-88 1988-89 1989-90 1990~-9l n r 29 28 34 59 60 32 34 38 34 Control unit SE(.~) i 0.321 0.071 0.196 0.537 0.431 _0.241 'o. 270 0.7580.320 0.088 0.049 0.078 0.070 0.064 .0-.077 0.083 0.078 0.090 n 31 32 26 58 58 28 28 44 36 TIeatment unit SE(i) i 0.387 0.033 0.431 0.439 0.471 0.107 0.445 0-.657 0.274 0.087 0.033 0.105 0.070 0.067 0.058 0.096 0.072 0.078 .f of equal i(.~) 0.578 0.774 0.075 0.157 0.565 _ 0.006 0.509 0.250 0.487 Winter conditions in 1990-91 were more typ~ca1 and estimated fawn survival rates on the control (0.320) and treatment (0.274) areas declined to near past levels and did not differ significantly from each other (l- 0.487). -Although deer density has been lowered on the treatment area, our previous efforts at lowering density by trapping in 1985 and ~986 indicated a considerable reduction will be required before there is a significant impact on survival. Further, stress from increased harassment during the montholong late hunting season may tend to enhance mortality on the treatment area. A higher than expected number of radio failures compounded the problem of poor trapping success (Table 2). Nine fawn radios were assumed to have failed; however, it is possible that at least some were on fawns killed during the late season and not reported. Most failures occurred with units purchased from 2 new vendors. As expected, hunting and starvation were major causes of fawn mortality on the treatment area. Nine fawns (27%) were known to have been shot and 8 (24%) were determined to have starved. In contrast, predation was the major mortality cause on the control area accounting for 10 fawn deaths' (37%) with .__.another 6 (22%}_dead of sta~ation ..'These numbers and survival rates may s.till change because effor_ts to account for all fawns will continue until fall, 1991. �32 Table 2. Cause of mortality treatment units of the Ridge of collaring in November and through 1990-91. Percentages Unit Winter No. of fawns Censored 1982-83 1983-84 1984-85 1985-86 1986-87 1987-88 1988-89 1989-90 1990-91 Treatment 1982-83 1983-84 1984-85 1985-86 1986-87 1987-88 1988-89 1989-9{} ,. 1990 .• 91 . Control for radio-collared mule deer fawns on control and study area in Piceance Basin, Colorado, from time December until the following 15 June 1982-83 are of total uncensored· fawns. 28 28 34 59 60 32 34. 38 34 31 32 26 58 58 28 28 44 ·36 1 7 11 6 2 4 14 7 1 1 4 9 5 3 9 3 Starvation % No. 15 22 16 10 14 22 10 3 6 15 27 8 17 16 19 9 6 8 56 79 59 21 26 73 33 13 22 50 87 36 35 30 68 36 17 24 cause Mortalit;)!: PIedation Hunting % % No. No. 4 4 5 7 17 15 14 19 15 31 5 17 Other No .. % 1 7 3 7 3 1 2 3 1 1 5 5 -4 3 14 2 2 18 20 11 9 2 2 9 2 3 2 11 13 1 1 33 7 10 9 22 25 4 4 3 9 .... 5 . 9 8 14 27 4 15 6 7 23 13 4 7 ._.Uncensored fawns are those with nonfai1ing radios or with collars ehac; did not drop off prematurely. Adult Doe Survival Twenty-seven does were radio collared, which in~reased numbers to 39 on the control area and 42 on the treatment area. Another 14 mature and 4 yearling does and 16 year1i~g bucks were measured and released. All yearlings were ear tagged for future identification as known-age. Compared to fawns, adult doe survival has been relatively high from year to year with little annual variation (Table 3) .. Through 15 June 1991, doe survival was 0.949 on the control area and 0.853 on the treatment area; the difference being mostly due to hunting mortality as only 1 deer on each area died from non-hunting causes. As with fawn radios, failures also were higher than expected with adult radios. There were 10 assumed failures but, again, some may have been for does killed during the late season and not reported. Seven does were killed during the late season. One had been trapped on the control area. The trapsite is close to the boundary between the 2 areas, so it is possible the deer was on the treatment area when killed. Of the 2 does not killed by hunters, 1 was killed by a mountain lion (Felis concolor) and the other ~ied from an undetermined cause during late February. These·numbers and survival rates-ean still change because adult survival is·calculated on an annual basis from 1 December to 30 November. �33 Table 3. Annual (1 Dec-30 Nov) survival rate estimates (i) for radiocollared adult female mule deer on control and treatment units of the Ridge study area in Piceance Basin, Colorado, 1982-83 through 1990-91. 'Winter 1982-83 1983-84 1984-85 1985-86 1986-87 1987-88 1988-89 1989-90 1990-91· • n 10 15 9 23 27 137 23 40 ContIol unit SE(i) i 0.800 0.779 1.000 0.955 0.709 0.818 0.857 0.765 0.949 0.126 0.113 0.044 0.093 0.116 0.132 0.105 0.035 lI!i:atmentunit SE(i) i n 11 15 10 21 17 11 5 28 35 0.909 0.929 1.000 0.900 0.811 1.000 0.800 0.672 0.853 0.087 0.069 0.067 0.099 0.179 0.089 0.061 .f of ' equal i 0.448 0.271 1.000 0.486 0.544 0.329 0.854 0.179 0.175 Survival rate estimates for 1990-91 are only to 15 June 1991. All radio-collared deer were located 3 times (January, February, and ,March) to check for movements between the treatment and control units. No fawns were located off the unit on which they-were trapped during any of the 3 periods. Only 4 does from the treatment Unit were located 1 or more times on the control unit, and 1 doe from the control unit was located 2 tf~es on the trea~ent unit. Thus, no major:movements ~ave been detecte4 that might be attriouted to the ~educed density on the treatment unit. Productivity 'We estimated post-season fawn:doe ratios to serve as a crude index to possible changes in productivity, i.e., recruitment to December or January, between the control and treatment ,areas. In 1988, the year before the first late season, ratios were not significantly different (f> 0.050), 73 and 70 fawns/100 does on the control and treatment areas, respectively. In 1989, the'ratio on the treatment area (106:100) was significantly higher (l< 0.050) than on the control (63:100), but was too high to be explained by the number and composition of deer removed. In 1990, surveys were flown before and again after ·the late season to see if we could detect an effect of the harvest. Pre-season ratios (control 79:100, treatment 81:100) and post-season ratios (control 67:100, treatment 64:100) were not significantly different (l> 0.050) between units, and neither were the decreases within units between the 2 periods (.f>0.050). As with the pre- and post-season line transect surveys, there were different observers for the 2 classification surveys. Age classification surveys will not be conducted in the future. Although we would expect an increase in fawn production as density declines, it would be difficult to detect such a change for several reasons. First, fawn:doe ratio estimates have been imprecise, usually no better than ±1520% of the mean at the 95% confidence level, which makes it d~fficult to ~~tect any except qui~e large changes. Second, ~he true fawn_production is confounded by t~e unkriown extent ot'mortality from birth to 6 months of age. TJhile it can be argUed that age ratios measure recruitment to 6 months of age, this information has little practical value and can also �34 be derived from census data. Therefore, the costs are better spent to expand line transect surveys because density estimates are more crucial to decisions on harvest levels. Harvest Several assumptions are made concerning harvest. One is that there is no harvest on the control area. We know this is not true, but assume the effect is negligible compared to the treatment area. Another is that there are no bucks killed. Again, we know this is not true. Several bucks killed in 1989 had antlers less than 5 inches long, which made them legal antlerless deer under the hunting regulations. Other bucks have either been checked or found abandoned in the field. Except for being illegal, these bucks have little effect on the study because they comprise a small proportion of the total population. Late season permits were increased by 25 to 400 in 1990 (Table 4). However, the estimated number of deer killed declined by 59 deer from the previous year to 392. The proportion of fawns in the'harvest (32%) increased slightly over that in 1989 (28%). Compared to 1989, more people reported hunting in 1990, but more were unsuccessful and more killed only 1 deer. The overall lower hunter success rate probably reflects a combination of lower deer density and snow conditions. that were worse than in 1989. Even with good snow conditions in 1991, we expect to see a further drop in hunter success because of still lower deer density. Table 4. Hunter participation and success and deer harvest estimates for the_December late·season on the treatment unit of the Ridge study area, 1989-90. 1989 No. 375 Number of Licenses· Number·of survey respondents 60 Hunter estimates - Did not hunt 81 Unsuccessful 37 Harvested 1 deer 63 Harvested 2 deer 194 Harvest estimates - Does Fawns Total 324 127 451 1990 % No. % 400 92 21.6 10.0 16.7 51.7 48 104 104 144 12.0 26.1 26.1 35.8 71.8 28.2 261 126 66.7 32.2 392b • Hunters were allowed to take 2 antlerless deer on a license. b One respondent reported harvesting a male fawn, but the deer checked in the field was a yearling (illegal) buck. This projects to 5 bucks and accounts for the difference between the estimated number of does and fawns harvested and the total. __ �35 Body Condition of Fawns Mean body weights of fawns on control and treatment units were within the range of means for the respective units during the previous 8 years (Table 5). Males were larger than females with respect to weight, total body length, and left hind foot length (l < 0.001) but, for all fawns, no differences were detected between units (l ~ 0.239). Table 5. Weights (kg) and body measurements (cm) of mule deer fawns on control and treatment units of the Ridge study area in Piceance Basin, Colorado, 1982-91. Weight SD Unit Year n Control 1982 1983 1984 1985 1986 1987 1988 1989 28 28 34 60 58 33 34 40 34.6 31. 7 32.3 32.6 31. 9 29.9 29.5 32.7 1990 1982 1983 1984_ 1985 1986 1987 1988· 1989 1990 35 30 32-. 26 60 61 28 30 47 36 30.8 4.29 32.8 4.18 3.1232.3 32.3 . 5.07 32-.3 4.62 31. 7 4.13 30.2 5.34 28.8 4.13 30.6 3.33 30.7 4.41 Treatment • n- h c nn- X 3.10 4.40 4.65 4.02 3.89 3.60 3.10 3.31 Total body l~ngth g SD Left hind foot length g SD 124.0 124.2 123.9 124.4 128.1· 127.3 123.8 131.0 4.64 5.65 7.25 6.26 6.53 6.12 7.83 5.81 41.1 40.6 40.8 41.1 41.0· 40.8 41.0 41.8 126.5 121. 7h 123.6 124.7 124.4 126.0· 127.5 124.9 126.6 127.6c 9.02 5.45 5.53' -7.25 6._28· 6.62 8.86 7.07 5.33 6.57 40.8 1.75 41.1h 1.65 40.6 1.34 89 40.8 _1 .. 40.8 1.77 41.0lL 2.11-41.2 1.66 40.6 1.88 40.7 1.41 41.1c 1.69 1.08 1.73 1.53 1.48 .95 1.72 1.37 2.16 60 31 32 Body condition was also indexed by the ratio of body weight to total body length. As with the separate measurements, there was no difference in mean ratios between units (l- 0.297). Age Structure and Body Condition of Does As in 1989, age estimates from dental cementum and from examination of lower jaws were inconsistent, particularly with the younger (yearling and 2 years old) and the older (>7 years old) age classes. Compared to Jaw aging, dental cementum tended to overestimate the age of younger animals and underestimate the age of older animals (Fig. 2). We are quite confident that we can accurately age yearlings and most 2-year-01ds from jaws. On the other hand, limited tests of the dental cementum technique with known-age teeth suggest errors for these 2 age classes may approach SOX, all biased high. Therefore, all analyses are based on age estimates derived from jaws. . �36 The estimated age structure of does harvested differed between the regular and late seasons (l- 0.050). During the regular seasons, more yearlings and fewer old (>7 years) deer were killed suggesting a differential vulnerability (Fig. 3). We do not know the true age structure of the population, but assume the late season harvest data are more representative because of the greater intensity of hunting pressure and the better hunting conditions. Age structures almost differed significantly between years (l- 0.087). The trend was towards more yearlings and fewer old animals in 1990. However, if the various ages of deer are being removed in similar· proportions to their presence in the population, we would not expect large changes in structure over time. Rather, the greatest effect would be from annual changes in fawn survival as it affects the number of yearlings recruited into the population. the increased proportion of yearlings killed during the 1990 late season did follow a winter of exceptionally high fawn survival. If this relationship holds true, we would expect the proportion of yearlings in the December harvest to drop in 1991 because fawn survival in 1990-91 was below 30%. As expected, carcass weights of adult does killed during the regular and late seasons in 1990 (44.4 kg, SD - 5.82) were greater than for yearlings (37.2 kg, SD - 4.12) (l< 0.001). Also, all deer harvested during the regular seasons averaged about 2 kg heavier than those taken during the December late season (l < 0.001). No differences in mean weights were found between deer killed in 1989 and 1990 (l- 0.618). There were no differences in live weights or total body lengths of adult does trapped in 1989 and 1990 (l~ 0.426), or between study units (l0.318) ·within years (Table '6)~ Likewise, li~e weights and total body leng,ths of yearling d~es did not differ between'years (f ~ 0.308), but ye,arlings on the treatment Unit averaged t?ear_ly6 cm Longez chan those 'on the control unit (l- 0.054). . Table 6. Weights (kg) and body measureme.nts (cm) of yearl~ng and adult female mule deer on control and treatment units of the Ridge s~udy area in Piceance Basin, Colorado, 1988-90. Unit Year n X Total bod:t:length SD X We1&bt SD Left hind foot length SD X IeAIl1n'gs Control Treatment 1988 1989 1990 1988 1989 1990 2 2 10· 2 7 8 46.2 46.0 49.4 50.2 53.3 50.8 1.91 6.43 2.38 0.35 9.61 3.38 146.1 148.4 147.9 151.2 158.7 150.1 10.75 2.26 2.49 3.18 11.03 4.94 45.8 47.8 45.8 46.0 46.7 45.6 0.99 3.04 1.08 168.6 166.7 165.9 166.8 5.20 6.98 6.76 5.81 48.1 47.3 47.8 48.1 1.10 1.09 1. 32 1.44 0.78 1.26 Adults Control Treatment 1989 1990 1989 1990 19 21 39 25 67.7 66.9 65.0 67.6 • Sample size for weight is 9. -'. 5.22 5.51 5.78 5.14 �Body Condition of Yearling Males There were no diffe~ences in mean antler lengths of yearling males between study units (l~ 0.782) or years (l~ 0.609) (Table 7). Live weights were nearly significantly different among years (l- 0.086). Yearling males on the treatment unit averaged nearly 5 kg heavier than those on the control unit (l- 0.004) and were nearly 8 cm longer in total body length (l- 0.02l). There were also differences in body length among years (l- 0.014) with the mean length in 1988 (148.5 cm) smaller than in 1989 (157.4 cm) and 1990 (157.1 cm). There were no differences in left hind foot length between areas (l- 0.093) or years (l- 0.836). Table 7. Weights (kg), body measurements (cm), and main antler beam measurements (cm) of yearling male mule deer on control and treatment units of the Ridge study area in Piceance Basin, Colorado, 1988-90. Weight Total bodv 19th Left h1l'ld foot 19th Unit Year n ! SO ! SO ! SO Control 1988 1989 1990 1988 1989 1990 6 2 2 6 1 9 54.0 48.5 52.2 51.8 60.8 60.6 4.91 5.30 3.99 4.01 145.1 151.8 154.8 151.9 168.5 157.6 11.53 8.13 6.67 6.07 47.4 46.7 48.0 48.5 50.0 48.7 1.39 0.71 3.52 1.19 Treatment 3.20 5.75 1.08 Main antler beam length Left Right SO SO t ! 16.9 15.8 16.6 17.3 14.5 19.3 3.49 1.77 4.47 3.47 5.52 16.4 18.4 15.6 16.9 13.5 20.1 2.30 0.49 4.03 4.11 6.07 SUMMARY The questionable accuracy and imprecision of recent deer density estimates based on aerial line transects mandate a cautious approa~h to evaluating the extent of the reduction on the treatment unit. The 1990 post-season density estimate indicates we have achieved the desired reduction, :-but co'rolLary data suggest the population is stil·l above our goal. Therefore, we consider 1 additional year of reduction to be necessary. Thereafter, the number of licenses will be reduced to a level that will maintain the desired density. Adjustments in the timing and length of the late season are also contemplated to allow a greater period to complete trapping, to reduce the period of stress on the deer,' and to reduce the cost of collecting harvest data. Although significant differences were found between many of the parameters we estimated, it would be surprising if they were influenced to any great extent by the reduction in deer density that has occurred thus far . .Rather, they probably are more a result of annual variation that makes it extremely difficult to separate treatment effects from environmental "noise". LITERATURE Bartmann, R. M. population. CITED 1990. Compensatory effects of harvest in a mule deer Colo. Div. Wildl., Wild1. Res. Rep. July:187-196. Kaplan, E. L., and P. Meier. incomplete observations. 1958.' Nonparametric estimation from J. Am. Stat. Assoc. 53:457-481. �Pollock, K. H., S. R. Winterstein, C. M. Bunck, and P. D. Curtis. 1989. Survival analysis in telemetry studies: the staggered entry design. J. Wi1d1. Manage. 53:7-15. Prepared by &/_~ IRichard M. Bartmann Wildlife Researcher 90r---------~------------------------------~~ CONTROL - 80 a: 70 C ..._, 60 - .•• ~ TREATMENT -- N ::E ~ ..._ w w \ \ ~ CiS 50 1------·-----------------------------------------,···--·---\----\ Z \ \ W C 40 __ ._ __ _ _--._-_ ..--. .. .. .. \ \ .... --... -.- ...----.-- ..... ---.~.-.-----. \ \ , '. 30~------~------~--------~------~------~~ 1986 1987 1988 1989 1990 1985 YEAR Fig. 1. Deer density estimates from aerial line transects during early winter. on control and treatment units �39 +5 6 : +4 (J'J •••• Z W +3 5 +2 7 8 2 W AGREE 6 16 17 17 9 a:: o Z a:: US >;,.... Z -c -, ~ 0:E 2 I 11 2 4 17 3 6 2 2 12 -2 3 8 4 2 11 -3 1 4 3 8 1 5 2 1 -1 -4 3 1989 -5 3 -6 +7 +6 ; ; ; +5 , 1 i 1 ·1' j . -_ J ! 1 I 3 ; +1 I 19 1, 13 I 11 26 2 ~ ~ , , +4 , , ; I , -~ AGREE - -1 > W 0 I , ,I +2 0 ! 1 i o -_ +3 a: u, Z 17 : W C!l 8 1 +1 :E 2 6 . - 0-0 4 5 , 2 1 , 5 2 I 6 , ! ! 7 I 4 2 -2 2 2 -3 I : 8 3 9 I : 2 : 1 2 I 5 6 1 3 2 1 -4 2 17 I 15 I 4 3 3 , 2 1 1990 , -5 1 ; -6 1 2 1 345 6 7 >7 JAW AGE (YEARS) Fig.- 2. Comparisons of deviations between dental cementum and jaw/incisor-based age estimates of does harvested during the 1989 and 1990 hunting seasons on the Ridge study area. Values are numbers of animals. �40 • - REGULAR SEASONS .• - LATE SEASON 50 ~----------------------------------------------~ 1989 40 ---- -.---- ..- --- - - - -- - 30 ------_._--_._ .. __ , - - -..- . I ._ __ .._ --_._ _ _ I·· _._ ...•. I I 20 I- Z W 0 ~------~----~------~----~------~----~------~ ~ W c.. 50 ~------------------------------------------------~ 1990· . 40 ~-----------~---.-------- .. ..-.-------.-------~. _ _-_ _ _ _ ..•......... _ _--_ _. .. - ...... -.- .--f..-I --_._--_ _. __ ._---_ _._ _ _ - - -. .................. _/I I l 10 --._-- 1 2 3 4 5 6 7 >7 ESTIMATED AGE (YEARS) Fig. 3. Estimated study area, age structure 1969 and 1990. of does harvest during regular and late seasons on the Ridge �Colorado Division of Yildlife Yildlife Research Report July 1991 JOB FINAL REPORT State of ~C~o~l~o~r~a~d~o _ Project No. Y-IS3-R-4 Elk Investigations York Plan No. Job No. 2 Period Covered: Author: Mammals Research Trapping, Transporting, and Maintenance of Elk at Livestock-Elk Grazing Study July I, 1990 - June 30, 1991 G. D. Bear Personnel: Bert Rakestraw, Chuck Yoodward Abstract Four years of field work have been comple"ted and tech~ical publicati~-!_lS are being prepared under Federal Aid Reports York Plan 3, Job 5; and York Plan 9A, Job I (Impact of Elk Yinter Grazing on Livestock Production). ��43 TRAPPING TRANSPORTING AND MAINTENANCE OF ELK AT LIVESTOCK-ELK GRAZING STUDY J J G. D. Bear P. N. OBJECTIVE To provide assistance to the Livestock-Elk Grazing Study near Maybell, Colorado, by capturing and maintaining an eXperimental elk herd. SEGMENT OBJECTIVES Same as P. N. Objective. METHODS AND RESULTS The primary purpose of this job was to assure the experimental pastures near Maybell in northwestern Colorado were properly stocked with elk and cattle during the designated grazing periods, which is a satellite of a more detailed job reported on by D. L. Baker (Federal Aid Report Work Plan 3, Job 5) and N. T. Hobbs (Federal Aid Report Work Plan 9A, Job 1): Impact of Elk Winter G~azing on Livestock Production . • 'Four years o-f field research has been completed and the final results ar~ :being prepared.~oi·technical pub~ication. . Prepared by _~ -i',--·__ ceorge:D.iear SJ. ~_"__e_e_,,--::~~ Wildlife Researcher ��45 Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o _ Project No. W-153-R-4 Work Plan No. Elk Investigations Job No. 6 Period Covered: Author: Mammals Research Effect of Elk Harvest Systems on Elk Breeding Biology July I, 1990 - June 30, 1991 D. J. Freddy Personnel: M. Miller, M. Cousins, C. Wetherill, Colorado Division of Wildlife; D. Bowden and G. White, Colorado State University; E. Ryland, Forbes Trinchera Ranch. Abstract . We· evaluated' effects of blood type. (plasma or se~), time 'sinc~'collection,· and storage temperature on progesterone concentrations in whole bloo~ collected fro~ 4 captive pregnant elk in December 1990 and May 1991~ '-Effects~ of blood. type, time, and temperature varied between months. In December, progeste~one was higher in serum than plasma (l_ 0.015) and higher in refrigerated samples (f.'_ 0.045), but not affected by time since collection (l_ 0.687). Plasma stored at ambient temperature provided the most stable values. In May, progesterone was not affected by blood type or temperature (l > 0.635) but markedly Lncreased in all samples, except; refrigerated serum, with time since colleetion (l _ 0.. 0001). Refrigerated serum provided the most stable values. In both months, progesterone did not decline with time since collection. These data suggest that progesterone values in samples collected by hunters would have a tendency to be higher, not lower, than actual progesterone levels. We continued to collect reproductive tracts from female elk harvested by hunters on the Forbes Trinchera Ranch. Pregnancy rates for adult cows (~ 1 yr old) were 61% and were the lowest recorded since 1986. This low rate was associated with low pregnancy rates in cows 1-3 years old which may reflect effects of low moisture during the last 2 years. Fetal sex ratios approached unity for the first time since 1986 and were 46 M: 54 F. One set of female twins was observed. Sizes of male and female fetuses increased from 1989. Conceptions occurred from 13 September.to 7 October, a 25 day interval, with a median date of 23 September. This was the shortest conception interval and earliest median date observed in this population. Brucellosis Was not detected in 45 blood samples from predominately female elk. Average age of bull eLk har{ested on_Forbes TriJlchera has st.~adily increased while ages of harVested'b~ck deer and female elk have remained,relatively stable. Average age of female deer harvested abruptly increased' in 1990' to 4.8 years. ��47 - EFFECT JOB PROGRESS REPORT OF ELK HARVEST SYSTEMS ON ELK BREEDING BIOLOGY David J. Freddy P. N. OBJECTIVE To evaluate effects of harvest systems on breeding biology of elk. _ SEGMENT OBJECTIVES 1. Continue to determine reproductive status of elk on the Forbes Trinchera Ranch using fetal collections and blood assays. 2. Continue to determine physical condition of elk and deer on the Forbes Trinchera Ranch by collecting body weights, antler weights and measurements, and ages of animals harvested. 3. Complete, by June 30, 1991, a Program Narrative (approved study plan) to assess reproductive, body weight, and survival responses of elk to large scale habitat improvements on transition and winter ranges. Study would begin in FY 91-92. METHODS Blood Assays - Pregnancy Testing We evaluated effects of time and ambient temperature on progesterone concentrations in plasma and serum collected from elk (Cervus elaphus). Using a syringe, we collected 60 cc of whole blood via the jugular vein from ~ yearold captive female elk on 26 December 1990 and again on 14 May 1991. In December, we collected blood from 4 pregnant and 1 non-pregnant elk and in May, we sampled the same 4 pregnant elk (about 35 days prior to term) and 1 different non-pregnant elk. We used xylazine (0.3-0.4 mgfkg) or medetomidine (0.05 mgfkg) to calm elk prior to collecting blood. Upon collection, blood from each elk was immediately divided into 20, 3.0 cc .subsamples and maintained at ambient temperature (13-16 C) during the 1 hr when blood was collected from all elk. These 20 subsamples were allocated as follows: 1) 10 were placed into heparinized glass tubes (plasma) with 5 each to be stored at 22-24 C and 2-4 C for up to 24 hours, and 2) 10 were placed into non-heparinized glass tubes (serum) with 5 each also stored at 22-24 C and 2-4 C for up to 24 hrs. At 1 hr post-collection (Time 0), 1 sample from each blood and temperature treatment· for each elk (4 samples/elk) was centrifuged, and plasma and serum were harvested and frozen at -18 C, and all remaining samples were placed in either a refrigerator or container maintained at ambient temperature. At 3, 6, 12, and 24 hours thereafter, samples were removed from their respective thermal environments, centrifuged, and plasma and serum were harvested and frozen at -18 C. _.Prostesterone ~0!lcent~~tions in each sample were ~~termined by radioi~unoassay on 7 JanuAry o~ 27 May 1991 by the Physiology Laboratory, Colorado. State University, Ft. Collins, CO. ~~Qeesterone concentrations transformed to log; �48 were analyzed using analysis of variance with repeated measures (serial blood samples for time intervals) (Proc GLM, SAS 1988). We also continued to monitor progesterone levels in ant1er1ess elk harvested by hunters in December, 1990, on the Forbes Trinch~ra Ranch. Hunters were instructed to obtain blood from the thoracic cavity of elk immediately after harvesting their elk and keep the non-heparinized vials of blood cool until depositing vials at ~heck stations. Blood was received from hunters usuallywithin a few hours of when animals were harvested and then refrigerated until centrifuging (usually within 12 hrs) at which time serum was frozen and stored at -18 C until processing. Hunters also collected the reproductive organs from their elk which allowed us to determine the pregnancy status of each elk. Blood ASSAYS - Disease Monitorin, Serum from elk harvested by hunters during December, 1990, on the Forbes Trinchera Ranch was tested for the presence of brucellosis in April, 1991, by the USDA Laboratory, Denver, CO. Serum was stored at -18C from centrifuging until tested for brucellosis. Fetal Collections Reproductive tracts of female elk were collected by hunters on the Forbes Trinchera Ranch from 8-17 December 1990. Tracts were deposited at check stations and kept cool until processing. Pregnancy status was determined from the presence of fetUses, embryos, and developed uterine tissue. Questionable uteri were preserved for later examination. Feta~ measurements w.ere made. on fresh ~pec::imens(subsequently pre~erVed) and .followed-definitions of·Aimstrong (1950). Fetal age was estimated from growth curves of-Morrison et a1. (1959). Inst~ctions showing hunters how to collect reproductive organs from elk wereimproved by providing better step-by-step illustrations: Body Measurements Eviscerated body weight, antler weight (including frontal bone), antler score (Nesbitt and Reneau 1986), and age were obtained for male elk and mule deer (Odocoileus hemionus) harVested on Forbes Trinchera Ranch. Eviscerated body weight, hind leg length, and age were also obtained for female elk and deer that were harvested. Age for all animals was estimate4 using both replacement and wear (Quimby and Gaab 1957, Robinette et al. 1957) and dental cementum (Keiss 1969, Stevens 1987). RESULTS AND DISCUSSION Blood Assays Progesterone-Temperature and Time Experiment Analysis of the effects of blood type, temperature, and time since collection on progesterone concentrations was limited to the 4 pregnant elk. In these animals, progesterone at time 0 hours ranged from 1.31 to 1.52 ng/ml in December and 2.15 to 2.29 ng/ml in May (Table 1). Progesterone in the nonpregnant elk was S 0.16 ng/ml and at these low concentrations effects of _~l_oodtyp~_, time, and _~emperature wer~_ undetectable. �49 Table 1. Average progesterone concentrations in blood collected from 4 captive pregnant elk in December 1990 and May 1991. Progesterone determined at 0, 3, 6, 12, and 24 hours post-collection for plasma and serum stored at 22-24 C or 2-4 C. . Time Since Plasma Progesterone (ng/ml) Serum Progesterone (ng/ml) Collection (hr) 22-24 C 2-4 C 22-24 C 2-4 C December o 3 6 12 24 o 3 6 12 24 1.31 1.23 1.32 1.40 1.30 1.49 1.40 1.68 1.66 1.57 1.52 1.65 1.47 1.47 1.50 1.48 1.61 1.77 1.84 1.88 2.15 2.12 1.99 3.12 2.66 2.29 2.22 1.97 3.08 2.92 2.22 2.25 2.16 3.18 2.72 2.26 2.53 2.40 2.60 2.49 December Samples .' Progesterone was higher in se~ tha~ plasma (~ ~ 0.015) and'higher in refri"gerated t~an ambient samples (f - 0.045). H<;Iwever,progesterone ~as not 'affected by time since collection (l - 0.687; Table 2, Fig. 1) .. In-general, steady declines in progesterone did not occur with any of the treatments, but~ a steady increase in concentration occurred in refrigerated serum and the most stable values were in ambient plasma (Fig. 1). At 12 hours, refrigerated serum. concentrations had increased 20% (0.30 ng/ml) over values at 0 hours. May Samples Progesterone increased markedly with time since collection (f - 0.0001) but was unaffected by blood type (l - 0.615) and temperature (l - 0.635). All samples, except refrigerated serum, decreased slightly through 6 hours then increased at 12 hours post-collettion (Fig. 1). Refrigerated serum provided the most consistent values increasing only 10% (0.25 ng/ml) over values at 0 hours. Unlike December, time since collection was involved with all significant effects (Table 2). December and May Samples Pooled Progesterone was higher in May than December and, overall, increased with time since collection (Tables I, 2). Effects of blood type, temperature, and time on progesterone. were highly dependent upon the month of collection (Table 2). �.IV Table 2. Results of univariate tests from analysis of variance of progesterone values in plasma and serum stored at either 22-24 C or 2-4 C and centrifuged at 0, 3, 6, 12, and 24 hours post-collection. Whole blood obtained from 4 captive preiDant elk in December, 1990, and May. 1991, Effect Tested DF Prob > F December Blood Type Temperature Time Blood Type X Temp Blood Type X Time Temp X Time Blood Type X Temp X Time 1 1 4 1 4 4 4 0.0149** 0,0450** 0,6868 0.9429 0.5169 0.0159** 0,1152 Blood Type Temperature Time Blood Type X Temp Blood Type X Time Temp X Time Blood Type X Temp X Time 1 0,6149 0.6349 0.0001** 0,1324 0.0248** 0.1215 0.0433** 1 4 1 4 4 4 December and May Pooled Month Blood Type Temperature Time Month X Blood Type Month X Temp Month X Time Blood Type X Temp Blood Type X Time Temp X Time Month X Blood Type X TempMonth X Blood Type X'Time Month X Temp X Time Blood Type X Temp X T~me Month X Blood Type X Temp X Time " 1 1 1 4 1 1 4 1 4 4 1 4 4 4 4 0.0061** 0.0814 0.1097 0.0019** 0.0100** 0.0077** 0.0583** 0.3957 0.0573** 0.6289 0.1519 0.4550 0.0042** 0.1331 0.0363** The inconsistency of our results may indicate an inadequate number of test animals, highly variable RIA analyses, or possibly the need to validate RIA analyses specifically for progesterone in elk. Our data suggest that progesterone in either plasma or serum has a greater tendency to increase than decrease in concentration with time since collection. These results contrast with observed decreases in both plasma and serum progesterone in muskox (Rowell and Flood 1987). Our data also suggest that it is prudent to consistently control the storage conditions for whole blood to reduce var~ationJn progesterone assay~ and that yalues d~rived from plasma and serum should not be treated as equiva~ent data. �51 Our low threshold value of 1.8 ng/ml for pregnant elk in December/January (Freddy 1990) does not appear to be low because progesterone decayed in samples collected by hunters. We were concerned that samples obtai~ed by hunters might be misleading because of the potential time delay between obtaining whole blood from the harvested elk and centrifuging the blood. Progesterone-Forbes Elk Average serum progesterone concentrations in known pregnant elk have been ~ 2.13 ng/m1 and for known nonpregnant elk, S 0.34 ng/ml in all years since 1987 (Table 3). These data will be used to refine our predictive curve for determining pregnancy status of elk (Freddy 1990). Table 3. Serum progesterone (ng/ml) in known pregnant and nonpregnant adult elk (~ 1 year old) harvested by hunters on Forbes Trinchera Ranch 1987-1990. ~erum ~rogesterone Pregnant Year/Statistic (ngLml) Non~regnant llll Mean SD SE CV% n 3.53 2.42 0.41 68.5 35 0.30 0.26 0.09 86.0 8 2.79 1.38 0.21 49.6 -42 0.29 0.59 0.17 201.0 12 4.40 2.97 0.53 67.4 31 --0.34 0.27 0.11 80.1 6 ill.§. Mean SD SE CV% n1989 -_Mean SD SE CV% n 1990 Mean SD SE CV% 2.13 0.10 0.19 46.9 27 n Disease Surveys-Forbes 0.14 0.22 -0.05 155.7 16 Elk All serum samples collected during December, 1990, from elk on the Forbes Trinchera Ranch tested negative for brucellosis. The 45 samples were from 1 male calf, 7 female calves, and 37 adult females. Previous tests for brucellosis on serum collected in 1987 and 1988 were also negative (Freddy 1989). Fetal Collections-Forbes Elk Hunters provided 52 ~eproductive tracks from 54 female elk (including calves) harves ted.---- �52 Precnanc;y Rates Pregnancy rates in 1990 for adult cows (~ 1 yr old) were 61% and were the lowest recorded since 1986 (Table 4). This low rate was associated with pregnancy rates of 0, 50, and 67% in yearlings, 2-year olds, and 3-year olds, respectively. For all years, pregnancy rates for prime-aged adults (3-10 yr old) were about 90% but were 15% for yearlings and < 60% for cows aged ~ 11 years (Table 4). Pregnancy in calves (age 6 mos) was not observed. Table 4. Pr.snancy 9 6-90 r.t.. for as. cl..... 1986 4&'':IE.1 1987 la-, D f,·. D of famal •• lk coll.cted • 1988 1989 fE·. l:E!1 D D 2 7 6 3 4 1 2 3 7 0 S S lS 15 10 9 5 4 3 3 1 0 3 2 7 2 6 4 19 17 12 11 7 8 2 2 0 0 7 4 S 3 12· 12 5 5 3 4 Tot..l. 34 28 49 38 61 47 % Pr., 82 78 77 1 2 3-4 5-6 7-8 9-10 11-12 13-19 6 7 6 3 4 1 2 5 "4&. for ~2 frOID r.pl.c_ent and •• ~; on the Forb.. Trinch.r. 1990 D fE·. D 0 3 6 3 8 4 1 3 34 27 61 42 30 15 7 23 49 38 46 28 239 78 61 1 2 10 11 5 5 2 2 9 6 9 5 8 4 1 4 1986-90 fre. Ranch in D.cemb.r %EIi:·. S 21 54 37 28 15 5· 14 15 78 89 88 93 100 71 61 179 75 75 for 3+, frOID dent.l c_entUID. Litter size was 1 in all but 4 (2%) of 179 litters. The 4 sets of twins were: 2 females and 1 male and 1 female in cows 9 and 12 years old, respectively in 1986; 2 ff!ma1e~ in a 6-year-01d cow in 1989; and, 2 females in a 4 year. old ~ow in 1990. infected uteri not ~apable of supporting pregnancy occu~red in 5 (2%) of 239 adu1t:s examined. Infec:;tionswe're in ;I., yearling and 4 cows ~ .i3 years old with 3 found in 1986, 1 iri 1988, and 1 in 1989. Fetal Sex Ratios In 1990, the fetal sex ratio was 46 M:54 F and the ratio pooled among all years was 49 M:50 F (Table 5). Fetal sex ratios approached unity in 1990 for the first time since 1986 when collections began, and this occurred with the lowest. observed pregnancy rate (Tables 4, 5). Tabl. S. 9 -90 4&''lAl~ 1 2 3-4 5-6 7-8 9-10 11-12 13-19 Tot.la F.t.l .ex r.t.io. for ),9!W .s. cl..... 1987 H E 1l 1 1 4 3 3 0 2 3 17 0 2 1 0 0 2 1 0 6 1 4 1 0 1 0 0 0 7 of famal. .lk coll.ct.d 19§9 12§8 E !l H E !l H 0 0 3 2 3 11 2 7 2 2 1 1 0 0 1 1 12 24 0 0 1 .1 2 8 8 S 1 0 1 26 0 2 S 3 2 1 0 1 0 2 0 0 0 0 0 3 1 0 4 4 0 0 1 H o . 0 1 0 0 2 2 15 E !l H 0 0 0 0 1 1 1 0 0 3 0 1 3 0 6 2 2 6 7 4 4 1 2 0 12 24 0 1 13 on th. Forb.. Trinch.ra 1990 F 0 2 4 3 2 1 1 2 is 1986-90 !l H l 0 3 7 22 17 16 4 3 8 80 0 10 27 20 10 9 3 5 84 0 0 0 0 1 0 0 1 30 38 44 74 63 % H!la ~3 .' "4&a for ~2 frOID r.plac_ant. and .aar: "Fat.l .ax H-mala F-f-.1. U-unlmown. - 39 29 33 46 for 3+, frOID dent.l c_antUID. % !l Tot.l Fatu ••• Ranch in D.cemb.r 180 49 2 4 4 1 2 3 0 0 16 Hal· 100 41 45 46 62 31 SO 62 49 �, 53 Fetal Size Body weight, crown-rump length, and hind foot length for male and female fetuses were larger than in any previous year except for male fetuses in 1987 (Table 6). These larger fetuses occurred during what was considered to be the second consecutive year of below average moisture. Table 6, Year/ Statistic HeasuIements of e~ IIS!!!I Weisbt ~151 Ma.e [ema.e fetuses from Forbes Trinchera Ranch, Crown-Rump Bind Foot Lenl5th ~aml ~aml l£enl5th Hale Femal. [ema •• Hlle 1986-1990, 29 Nov-5 Dec 1986 Hean SO lllin III!X CV% n 20,9 7.0 11.9 29.0 33.5 6.0 90,2 16.7 63.5 115.5 18,5 17,0 86,0 9.5 72.0 94.0 11.1 5.0 60.4 33.2 12.0 135.0 55,0 24.0 141.4 21.1 113.0 180.0 14.9 12.0 66.7 ~9.7 23.0 120.0 44.5 15.0 60.0 45.4 4.9 149.0 27,6 13.8 12.2 58.5 50.0 17.0 20.5 4.8 . 13.5 28.5 23.4 17.0 19.8 2.7 16.5 23.0 13.6 5.0 115.4 23.3 66.0 151.0 20,2 24.0 42.3 10.9 31.0 68.0 25.8 12.0 30.3 8.8 14.0 46.0 29.0 24.0 120.0 19.9 77,0 163.0 16.6 26.0 121.7 17.9 87,.0 150.0 14,·7 15.0 32.6 7.7 17,0 47.0 23.6 26,0 33.1 7.0 20.0 45.0 21.2 15,0 24.0 102.4 37.5 35.0 169.0 36.6 12.0 111.5 33.4 38.0 163.0 30,0 24.0 27.9 12.3 13.0 53.0 44.1 11.0 29.9 10.8 10.0 48.0 36.1 23.0 78,4 43.0 31.0 166.0 54.9 14,0 128.0 25.1 84.0 170.0 19.6 13.0 127.6 22.6 95.• 0 161.0 17,7 15,0 35.1 9,7 19,0 51.0 27.7 13,0 35,7 10.5 22.0 58.0 29.5 15.0 12-14 & 19-21 Dec 1987 Heail SD lllin III!X CV% n 118.7 54.7 66.0 242.0 46.1 12.0 10-12 & 17-1·9Dec 1988 Hean SO IlliD III!X CV% D 74.5 35.2 22.0 162.0' 47.3 26,0 ;.- 9-11 & 16-18 Dec 1989 Hean SD IlliD III!X CV% D ·57.8 59.9 3.5 188.0 103·.6 12.0 7S.7 8-17 Dec 1990 Hean SD IlliD III!X CV% n 92.2 52.5 26.0 190.0 56.9 13,0 Concention Dates Conceptions occurred from 13 September to 7 October, a 25-day interval, with a median conception date of 23 September. This is the shortest conception interval and the earliest median date for breeding among all years (Fig. 2). One hypothesis that might explain this compressed'breeding period is that breeding was more restricted, than in previous years, to those prime-aged.cows that achieved adequate body condition to breed during a prolonged period of drought. Larger and relatively less variable sized fetuses may also reflect -_fewer fetuses fr~m young' cows (Table 4)." �forbes Elk and Deer Harvests Average ages of buck deer and female elk harvested from 1986 to 1990 have remained relatively stable with generally increasing, but variable, harvests (Table 7). Average age of bull elk harvested has steadily increased along with increasing harvests, and this most likely reflects greater selectivity for and improved efficiency in finding older bulls for harvest (Table 7). Average age of female deer harvested remained relatively stable from 1986-1989 but abrUptly increased in 1990 (Table 7). This increase may reflect poor recruitment of young deer in 1989. Table 7. Average age of adult (~ 1 year old) deer and elk harvested on the Forbes Trinebera Ranch, 1986-90, Species-Season/ Statistic· 1986 1987 1988 1989 1990 4.8 0.2 72 4.9 0.2 93 4.8 0.2 87 5.2 0.2 102 5.7 0.2 117 5.6 0.2 87 6.6 0.2 109 6.6 0.2 lOS 6.0 0.2 11S 6,0 0.2 lOS ·Bull Elk - PrivateMean SE. n Buck Deer - Privateb Mean SE n Female Elk Publ~cc ~ 5,-5 O.S 34 -Mean SE n 5.2 0.6 51 5.4 0.5 64 5.7 0.6 51 - 5.4 -0,6 46 Female Deer - Publicd Mean SE_ n -Age bAge CAge dAge 3.S 3.5 3.5 3.6 4.S 0.3 0.2 0.2 0.2 0:2 .50 . 113 115 153 134 based on tooth replacement and wear. based on tooth replacement and wear. for 1-2 from replacement and wear; for 3+, from dental cementum. for 1 from replacement and wear; for 2+, from dental cementum. Eviscerated body weight, antler weight, and antler score were obtained for nearly all male elk and deer harvested. Eviscerated body weight and hind leg length were also obtained for nearly all female elk and deer harvested. These data have not as yet been completely summarized. Program Narrative A program narrative regarding elk survival rates was not completed this segment because long-term research needs for elk were being evaluated. z; �55 LITERATURE CITED Armstrong, R. A. 1950. Fetal development of northern white-tailed Amer. Mid. Nat. 43:650-666. deer. Freddy, D.~. 1989. Effect of elk harvest systems on elk breeding biology. Colo. Div. of Wildl. Game Res. Rep. July:35-60. 1990. Effect of elk harvest systems on elk breeding biology. Colo. Div. of Wildl. Game Res. Rep. July:19-29. Keiss, R. E. 1969. Comparison of eruption-wear patterns and cementum annuli as age criteria in elk. J. Wildl. Manage. 33:175-180, Morrison, J. A., C. E. Trainer, and P. L. Wright. 1959. Breeding seasons in elk as determined from known-age embryos. J. Wildl. Manage. 23:27-34 . .Nesbitt, W. H., ana J. Reneau (eds.). 1986. Boone and Crockett Club's 19th big game awards. Boone and Crockett Club, Dumfries, Vermont. Quimby, D. C., and J. E. Gaab. 1957. Mandibular dentition as an age indicator in Rocky Mountain elk. J. Wildl. Manage. 21:134-153. Robinette, W. L., D. L. Jones, G. Rogers, and J. S. Gashwei1er. 1957. Notes on tooth development and wear for Rocky Mountain mule deer. J. Wi1dl. Manage. 21:134-153. 'Rowell, J..,-and P. F. Flood. 1987.. Changes in muskox 'blood progesterone' concentration between' collection and 'ce·ntrifugation. J. Wildl. Manage. =-51:901-903. SAS Institute, Inc. 1028pp. 1988. SAS/user's guide. SAS Inst. Inc., Cary. N. C. Stevens, M ..L. 1987. Apparent accuracy of cementum annuli for estimating ages of mule deer. M. S. Thesis, Colorado State University, Fort Collins. Prepared by -4~"""~WW;id'_J""'~-"'1,,--~_"'~,-=·:!f;=..I.~..o:;.;:~-· _ Wildlife Researcher �56 1.4 . PLASMA 22-24 C SERUM 22-24 C ----.---. 1.2 -t--------------PLASMA 2-4 C SERUM 2-4 C o - ---fi--· c::- E 1 C) .s ...-- w z o a: ...8-- _ ---------------0 MAY w til w ~ ~ .--~ . 06 . -+--------------~--------------~~--~~-~--~--~---------l c.. ~. C( G) 3 0.4 0.2 DECEMBER o o 3 6 12 24 HOURS POST-COLLECTION Fig. 1. Average progesterone concentrations (log. ng/ml) in plasma and serum collected in December 1990 and May 1991 from 4 captive elk. Whole blood samples stored at 22-24 C or 2-4 C and centrifuged at 0, 3, 6, 12, and 24 hours post-collection. �57 so :0 :0 :0 I I :! I U) z 0 i= ~ 40: e, 0 0 :- 30 !Z w : : 0 a: w e, - 1986 1987 .......•.••..__ .. ~ ®1~~411988 ------_ .•. w Z 0 YEARLY MEDIAN DATES n =26 n =37 n =44 0 1989 n =35 I22J 1990 -- n =27 20 10 I I o 9/8 In ~ ~ 9/18 9/28 10/8 II 10/18 B T 10/28 11/7 11/17 MONTH AND DAY (BEGIN 5-DAY INTERVALS) ~------------------------------------------~ ~ •. so _ - MEDIAN DATE ~-----------~------------------~----------~~ ~ 40 -1------- ~ o z o o !Z w ~ w a, _ 1986-1990 n = 169 30 -4------- 20 -4-.-----~----- o 9/8 9/18 9/28 10/8 10/18 10/28 11/7 11/17 MONTH AND DAY (BEGIN 5-DAY INTERVALS) Fig. 2. Conception dates for elk on the Forbes Trinchera Ranch, 1986-1990. ��59 Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o _ Project No. W-153-R-4 Work Plan No. 3 Job No. Mammals Research Elk Investigations Elk Census Methodology Period Covered: Author: July I, 1990 - June 30, 1991 D. J. Freddy Personnel: R. Bartmann, G. Byrne, G. White Abstract .. Estimates of population sizes for elk and deer in the Troublesome sub-unit of ~iddle Park were obtained using systematically spaced aerial line transects. Additionally, an estimate~of popuiation size for deer was obtained using a random quadrat -(2.59 km2) sY$tem .. All flights were cortducted in Jan~ry, 1990,- and March, 1991, using a Bell-Soloy helicopter. The exponentialpolynomial (EXPL) sighting model provided the best combination of precision and model fit for both elk and deer. Precision (± 95% CI) ranged from ± 4350% and 13-38% for elk and deer, respectively. Estimates of population size varied with each sighting model and ranged from 2,364-4,263 for elk and from 3,908-7,496 for deer. Line transects provided higher estimates of total deer and better precision than quadrats in both years (l< 0:10). Differences between technique~ were greater than expected with quadrats estimating only 26-37% of the deer estimated by line transects. High estimates prov~ded by line transects were related to the-high proportion of groups of elk or deer seen ~i_thin-. the,center line interval compared to intervals away from the center line." A video .camera ,system with further. improyeni~nt~_may. provide a possible means.'to docunient groups along the center line interval. ± ��6l JOB PllOGllESS UPOB.T EIJC CENSUS METHODOLOGY David J. Freddy P. N. OBJECTIVE Evaluate methods to estimate numbers of elk during winter. SEGMENT OBJECTIVES 1. Determine efficacy of line transect methodology to estimate numbers of elk and mule deer sharing sagebrush-aspen-conifer winter ranges. Specifically, attempt to ascertain apparent problems with assigning observed groups to the ·center line" interval by using a video camera. 2. Compare estimates of mule deer density based on Lf.ne transects and quadrats in an area where both methods can be emp~oyed. 3. Prepare manuscript for publication. INTRODUCTION Methods to reliably esti~te numbers of ~lk (Cervus elap1;1us)have yet to be -developed. Bear et al. (1989):evaluated mark-res~ghting-to estimate population size, and they -found the method: provided-precise estimatj!s of popUlation size that were likely negatively biased; was sensitive to-colors of markers placed on elk; and was costly. Samuel et a1. (1987) and Unsworth (1990) developed and used sightability factors to correct for negatively biased counts of elk during surveys attempting to completely count all elk. This approach has merit although not having a fixed sampling design to determine those areas searched may lead to yearly variability in estimates due to changes in observers and patterns of search. These methods for elk are all subject to underestimating true population size as has been found in many efforts to estimate true densities of ungulates (LeResche and Rausch 1974; Bartmann et al. 1986; Pollock and Kendall 1987; Samuel et al. 1987). Underestimates occur because all animals are not observed on defined sample units such as quadrats or strip-transects. Line transect theory allows observers to miss animals, except those occurring directly on the center line of the transect and, therefore, could provide less negatively biased estimates of population size (Burnham et al. 1980; White et al. 1989). We chose to assess the field logistics and precision of aerial line transects as a sampling method to estimate numbers of elk. Secondarily, we also wanted to further evaluate line transects for estimating numbers of mule deer (Odocoileus hemionus) (White et al. 1989). The area selected for evaluating line transects was the Troublesome portion of Game Management Unit (GMU) 18 within Middle Park, northcentral Colorado. During winter, significant numbers of elk and mule deer concentrate into a 250 Iqn2 area.which can_be efficiently sampled with aerial surveys, Vegetatio~ ---within winter -ranges frequented by elk is primarily sagebrush (Artemisia tridentata), aspen (Populus tremuloides), conifer forests (Pinus conCorta, �62 Pseudotsugs menziesii, Pice. engelmanni), and mixed stands of aspen-conifer. For deer, winter ranges are dominated by sagebrush and aspen. from rolling hills to steep canyons. Terrain varied METHODS Two sets of parallel line transects, each having 26 transects systematically_ spaced at 1,000-m intervals, were flown to estimate numbers of elk and deer. These 2 sets resulted in transects occurring every 500 m across the sampled winter range. Transects were oriented on true north-south bearings perpendicular to changes in elevation and expected gradients in elk and deer densities (White et al. 1989), were delineated on 1:24,000 scale topographic maps, and were not marked with flight markers on the ground. Placement of transects allowed for counting elk and deer simultaneously. Line transects flown to estimate densities of elk totaled 948 km (588 mi) in length, were 1-15 km long, and were distributed within an area of 246 km2 (95 mi2) between elevations of 2,257-2,990 m (7-,400-9,800 ft). Transects were limited to those areas where elk generally reside during January and February. The same line transects were flown to estimate densities of deer but only deer found at elevations S 2,590 m (8,500 ft, primarily sagebrush habitat) were counted. With this restriction, line transects for deer totaled 602 km (374 mi) in length, were 1-14 km long, and were distributed within an area of 166 ~ (64 mi2) , which was also the area delineated for a quadrat (2.59 km2, 1 2 mi ) sampling system used to estimate numbers of deer in the Troublesome area during the last 22 yrs rcrn -1969).Trans~cts were conducted with a Bell-Soloy helicopter flown at 65-80 kmph (40: 50 mph) and 35-50 m above the ground or tree canopy. We flew each set of transects twice (4 replicate flights) and attempted to fly each set once in the morning and once in the afternoon but weather altered this scheduling of transects. Transects were flown in 1990 on 9-and 11 January and in 1991 on 1, 3, 4, and 8 March. A navigator and observer were responsible for observing elk or deer. The observer, seated on the right, estimated perpendicular distances to and counted those groups of elk or deer located from the transect center line to the right. The navigator, seated in the middle, maintained course bearing, and aided in locating groups on or near the transect line. Observers were experienced in aerial counts of elk and deer and practiced estimating distance intervals from the helicopter using markers placed at 10-m intervals along a practice transect line. Primary observers were different each year. We considered sets of transects to be independent and thus pooled results from the 4 replicate flights to derive estimates of elk and deer populations. We had no indication that counting elk or deer disturbed either sufficiently to cause them to move from 1 transect to another while flying one set of transects and thus we feel duplicated counts within a set of transects did not occur. Estimates of population size derived from line transects followed methods outlined by White et a1. (1989) and estimates derived from quadrats followed methods of Gill (1969) and Mendenhall et al. (1971). We _wanted--to compare estimates of population siZe -for deer derived from -lrite transects and quadrats. We, therefore, expanded an existing quadrat system �63 from 10 to 30 quadrats by drawing at random an additional 20 quadrats to improve precision of the estimate. Quadrats were flown on 10 January 1990 and 3-4 March 1991 using the same helicopter and pilot used each year for line transects. Quadrats and transects were flown at similar flight speeds and elevations above the ground. At least 1 corner of each quadrat was marked on the ground to aid in locating quadrats from the helicopter. The navigator and observer both searched for and counted deer. Estimates of population density were compared using a z-test. RESULTS AND DISCUSSION . Although we searched for deer and elk simultaneously on line transects, the 2 species were seldom seen in close proximity. Ye, therefore, believe that searching for both species had little effect on detecting either species. Ye found little evidence to suggest elk were moving prior to detection. Elk were often bedded or standing in aspen or conifer habitats where snow depths were 25-60 cm. However, deer moved in response to the helicopter more than did elk because snow depths did not deter deer from moving. In 1990, snow cover was nearly 100% but snow depth was only 4 cm at lower elevations while in 1991, many south-facing slopes were free of snow. Even with the mild snow conditions both years, deer were almost exclusively within the sampled area demarcated for deer. There were 2 and 1 group(s) of deer in 1990 and 1991, respectively, that were seen along line transects outside the sample area demarcated for deer quadrats and line transects. Line Transects-Elk . Estimated population size for elk varied with which· sighting probability- model was used. In 1990, estimated size ranged from 3,404 to 4,263 (Table 1). A minimum number of elk in the sampled area based on helicopter flights was 419 in January 1990 and 744 in January 1~88 (pers. ·comm. R. Thompson). Our estimates in 1991 were more variable and of lower precision because fewer groups of elk were encountered on transects. In 1991, we found elk were widely distributed outside our defined sample area because low snowfall had allowed elk to reside at higher elevations~ Ye, therefore, discontinued flights for elk after completing one replicate of each set of transects (Table 4). The EXPL models provided the best precision during both years which was ± 43% and ± 50% of the mean (95% CI, Table 1). Sighting curves were spiked at the center line both years indicating that probability of detecting elk away from the center line fell rapidly and effectively ended at 95 m (Fig. 1). This spiked distribution was largely responsible for the unexpectedly high estimates of population size. Enlarging or reducing the width of the center interval or the cut-point for strip width generally resulted in models that fit the data poorly. All models fit reasonably well with about equal quality (good fit - Chi-square l> 0.10; Table 1). �Table 1. Population estimates for elk based upon different sighting probability models for line transects, Troublesome sub-unit, Middle Park, January 1990 and March 1991, Pop. Size & 95% CI Density Center Interval/ Groups Chi-square Prob, (P) Elk/mi2 Cut Point (m) Mean Upper Lower Modela n 0-15 0-15 0-15 0-15 0-15 / / / / / 155 95 95 95 95 66 57 57 57 57 0.8252 0.7310 0.8248 0.7514 0.7309 3659 3664 3662 4263 3404 5232 5224 5380 9813 5053 2086 2104 1943 o 1754 38,5 38.6 38.6 44.9 35.a 24,9 4738 2364 EXPLb 0-15 / 155 27 0.6397 o 3247 6136 0.6470 358 34.2 EXPL 0-15 / 95 23 6194 3247 34.2 0.8163 302 NEXP 0-15 / 95 23 4163 12,506 43.8 0.8010 o EXPS 0-15 / 95 23 0,6470 2743 5184 301 28.9 EXfLc 0-15 / 95 23 aModels are: EXPL-exponential polynomial, NEXP-negative exponential, EXPS-exponentia1 power series. ~ese models provided the best precision: ±43% of the population mean in 1990; ±50% of the population mean in 1991. C!n these models, average group size was.based only upon the groups seen •within the cut-point truncat~on distanc~; other models used all groups seen to .calculate average group's ize .. Average number of elk per group tended to increase with distance away-from the ceriter interval (X - 0.30, slope positive). This was pronounced in groups observed at ~ 95 m which suggests a bias in detecting large groups beyond this distance (Fig. 2), In calculating population size, program TRANSECT uses all groups observed to calculate an average group size, regardless of the cutpoint for the sighting curve (White et al. 1989). We altered the program so that only groups seen within the truncation distance were used to calculate average group size which reduced estimates of population size for the EXPL . model 7-16% in 1990 and 1991 (Table 1). Groups were generally larger and more frequently observed in aspen and sagebrush than in conifer habitats but differences in average group size among major habitat types were not significant (ANOVA, E> 0.50, Fig. 3). Line Transects-Deer Estimated population size for deer also varied with which sighting probability model was used. In 1990, estimated size ranged from 5,021 to 9,541 and in 1991 from 3,908 to 5,158 (Table 2). The EXPL models provided the best precision during both years which was ± 13% and ± 38% of the mean (95% CI, Table 2). Precision declined in 1991 because average group size increased (6.08 to 7.55) and was more variable and total groups observed decreased (208 to 132). These changes reflected the more concentrated distribution of deer in 1991. Sighting models for deer were more variable in their goodness-of-fit than for elk, and in 1990 especially, models often fit poorly (Chi-square ... l < O._lO;_._Table2)'--· �65 Table 2. Population estimates for deer based up~n different sighting probability models for line transects, Troublesome sub-unit, Middle Park, January 1990. Pop. Size & 95% Cl Density Center Interva1/ Groups Chi-square Model· Cut Point (m) n Prob. (P) Mean Upper Lower Deer/mi2 1990 EXPL EXPLb NEXP EXPS EXPLbc 0-15 0-15 0-15 0-15 0-15 / 155 / 95 / 95 / 95 / 95 185 139 139 139 139 0.0001 0.0908 0.1420 0.2024 0.0908 5021 7496 7494 9541 7005 7144 8466 10,538 17,327 7992 2898 6526 4451 1746 6018 78.4 116.9 117.0 149.0 109.3 ll2l EXPLb EXPL NEXP EXPS EXfLc 0-15 / 155 123 0.1797 4483 6190 2776 69.9 0-15 / 95 101 0.1877 5158 8177 2139 80.5 0-15 / 95 101 0.2711 5156 7314 2998 80.4 0-15/95 101 0.1964 5771 10,783 757 90.0 0-15 I 95 101 0.1872 3908 6207 1610 61.0 -Models are: -EXP-L- exponential polynomial, NEXP - negative exponential, EXPS - exponential power series. bThese models provided the best precision: ±13% of population mean in 1990; ± 38% in 1991. cIn these models, average group size was based only upon the groups seen within the cut-point truncation distance; other models used all groups seen to calculate averag~ group -size. . As with elk, sighting curves were spiked at -the center line indicating that probability of detecting deer away from the center line fell rapidly and effectively ended at 95 m (Fig. 2). This spiked sighting curve was observed both years even ~hough primary observers were different each year. Similar sighting distributions for deer occurred with other observers and habitats, suggesting that these sighting distributions are a function of technique and not observer (Freddy 1990). As with elk, _this spiked sighting curve was largely responsible for the unexpectedly high estimates of population size. Average number of deer per group tended to increase with distance away from the center interval (X - 0.45, slope positive) and was again pronounced in groups observed at ~ 95 m (Fig. 4). Using only groups within the truncation distance to calculate average group size, reduced estimates of population size 7-24% in 1990 and 1991 (Table 2). Quadrats-Deer Estimated population size for deer was 1,848 in 1990 and 1,647 in 1991 (Table 3). Precision declined from ± 32% to ± 53% of the mean (95% CI) from 1990 to 1991. Deer were more concentrated in 1991 which resulted in more variablity in numbers of deer per quadrat. Estimates of population size were not different between years (~0.50). . �66 Table 3~ Estimated size of the mule deer population in the Troublesome subunit of Middle Park, January, 1990 and March, 1991 based upon deer counted on square-mile quadrats. Variances calculated using finite population correction factor and N - 64.1 mi2. 95% C.l, Precision Density Quadrats Deer/mi2 Lower Upper % of Mean n Mean Year 1848 1264 2431 28.8 1990 30 ± 32% 1647 25.7 1991 30 771 2524 + 53% Line Transects vs. Quadrats-Deer Line transects provided a higher estimate of total deer than did quadrats in 1990 (l< 0.001) and 1991 (l< 0.10) and generally provided better precision (Tables 2, 3). Population estimates derived from quadrats in 1990 and 1991 represented only 26 to 37%, respectively, of the deer estimated by the most precise EXPL models for line transects (Tables 2, 3; Fig. 5). We expected quadrats to underestimate true population size because area based sampling strategies assume 100% of the animals present are counted and this seldom occurs. In juniper-pinyon (Juniperus oseeosperma-Pinus edulis) habitats, observers detected only 65% of the known deer on quadrats (Bartmann et al. 1986).· In open sagebrush habitats frequented by our deer, we might detect 80% of the deer under optimal conditions (LeResche and Rausch 1974), and if true, the corrected estimated population of deer based on quadrats would be 2,310 and 2,050 in 1990 and 1991, respectively. Given a worst case scenario of detecting only 65% of the deer on quadrats, we would expect a true population of 2,843 and_2,534 in these-same years, respectively. Because line transects ~a.ve been found .to estimate 90% .of the true population ("Whiteet a1.,·-1989)we ·might_have-reasoned that line transects wo~ld provide an ~stimate of about 3,OOO-de~r instead of an est1mat~d 4,000-7,000. The data leave us in-doubt as to which method is most biased. Fiyin, Effort Actual flying time used to count elk and deer along line transects was consistent among replicated flights in 1990 (Table 4), In 1991, flying time was also consistent when transects were flown for elk and deer (replicates 1) and for deer only (replicates 2) (Table 4). Groups detected per replicate were somewhat consistent; although in 1990, flights conducted in the morning always detected more groups of either elk or deer. Line transects for deer accounted for about 65% of the total flying time devoted to transects that sampled both deer and elk. Compared to quadrats, line transects for deer used 1.3-l.8x the amount of flying time to sample the same geographic area. The amount of flying time devoted to replicating transects was dictated by our objective to detect 130 groups of elk and 200 groups of deer to achieve precision approaching ± 15% ("Whiteet al, 1989). In general, we did not achieve this desired precision suggesting that densities of groups were insufficient. �67 Table 4. Numbers of groups of 'elk and deer detected on transects and estimates of counting times for transects and quadrats flown in the Troublesome sub-unit, Middle Park, January, 1990 and March 1991. Groups Detected· Elk Deer Right Right Flight Method Countingb Time (mins) l2.2Q Trans. Trans. Trans. Trans. Set Set Set Set 1 2 1 2 Rep Rep Rep Rep 1 1 2 2 AM PM AM PM Trans. Totals 24 22 60 44 60 16 44 229 227 229 220 79 208' 90S 17 445 Quadrats (30) for Deer Only illl Trans. Trans. Trans. Trans. Set Set Set Set 1 Rep 2 Rep 1 Rep 2 Rep 1 1 2 2 PM AM AM PM Trans. Totals 21 12 n/a n/a 33 29 257 262 46 27 30 174 132 855 162 366 Quadrats (30) for Deer Only -Groups of elk and deer to the right of center line. . botime shown is the best estimate of flying time used to count anima~s. . ,. Flying. time to/frC?m for refueling not included. . Evaluation of Video Camera System We explored the potential to use a video camera system to document the accuracy of assigning groups of deer or elk to the center line interval of line transects. We mounted a Canon CI-20 miniature video camera (Sx8x10 cm) along the center console of a Bell-Soloy helicopter. The. camera was'wired to a Sony Video Walkman 8 mm recorder using Sony metallic particle color tape. Both wide-angle and telephoto lenses, ranging from 4.8 mm to 2S mm focal length, were used. To determine angle and width of coverage, we flew test flights down an airport runway where runway markers could be used to . accurately determine camera ~overage. All lenses provided coverage to either side of a hypothetical center line with the 16 mm providing the most acceptable coverage. We then flew both sagebrush and juniper-pinyon habitats where deer were present. Although deer were detectable on the video tape, primarily in open habitats, they generally could not be seen until the helicopter was close, thereby reducing the ability to detect groups at reasonable distances in front of the aircraft. Aircraft vibration, slow electronic shutter speeds, and rapid changes in exposure contributed to reduced quality of the video image. A better aircraft mounting system combined with newer cameras having faster shutter speeds and higher resolution may allow the camera to provide an independent estimate of groups within the center interval. �68 CONCLUSIONS Sighting distributions for elk and deer were spiked at the transect line during both 1990 and 1991. This characteristic of line transect data collected from a helicopter appears to be independent of species, observer, or habitat type. For Middle Park, line transects produced surprisingly high estimates of popUlation sizes for elk and deer, and this is attributed to the high proportion of groups observed in center interval of the transect. Estimates of deer population size derived from transects were significantly higher than estimates based on quadrats and were more precise. We expected differences but not to the degree observed and, therefore, are left with the difficult objective of determining which method is most biased. We found that intense efforts by the pilot, navigator, and observer were required to effectively fly line transects. Whether this effort is more or less intensive than quadrats, is open to debate; but, subjectively, line transects were more likely to increase observer fatigue. At the suspected moderate densities of elk and deer on our study area, we had difficulty acquiring the required numbers of groups to achieve desired precision for line transect estimates even though we replicated transects. Our data suggest that transects may be more costly to fly than quadrats depending upon desired precision. LITEBATQJE CITED Ba~tmann, R. M., L. H. Carpenter, R. A. Garrott. and D. C. Bo~den. 1986. A~curacy of helicopter counts of mule"~eer in pinyon-juniper woodland. vriai. Soc. Bull. 14:356-363. Bear, G. D., G. C. White, L. H. Carpenter, R. B. Gill, and D. J. Essex. Evaluation of aerial mark-resighting estimates of elk populations. Wildl. Manage. 53: 908-915. 1989-. J. Burnham, K. P., D. R. Anderson, and J. L. Laake. 1980. Estimation of density from line transect sampling of biological populations. W~ldl. Mono. 72. 202pp. Freddy, D. J. 1988. Elk census methodology. Rep. July (1):78-82. __ '. 1990. Elk census methodology. July: 31-43. Colo. Div. Wildl. Game Res. Colo. Div. Wildl. Game Res. Rep. Gill, R. B. 1969. A quadrat count system for estimating game population. Colo. Game, Fish, & Parks Game Info. Leaflet 76. 2pp. LeResche, R. E., and R. A. Rausch. 1974. Accuracy and precision of aerial .moose censusing. J. Wildi. Manage. 38:175-182. Mendenhall, Y., L. Ott, and R. L. Scheaffer. 1971. Elementary survey. sampling'. DUxbury Press, Belmont, Calif. 247pp . Pollock, K. H., and W. L. Kendall. 1987. Visibility bias in aerial surveys: a-review of estimation procequres. J. Yildl. Manage. 51:502-510. �69 Samuel, M. D., E. O. Garton, M. W. Schlegel, and R. G. Carson. 1987. Visibility bias during aerial surveys of elk in northcentral Idaho. Wildl. Manage. 51:622-630. J. Unsworth, J. W., L. Kuck, and E. O. Garton. 1990. Elk sightability model validation at the National Bison Range, Montana. Wildl. Soc. Bull. 18:113-115. White, G. C., R. M. Bartmann,' L. H. Carpenter, and R. A. Garrott~ 1989. Evaluation of aerial line transects for estimating mule deer densities. J. Wildl. Manage. 53:625-635. �IU 20 ELK TROUBLESOME ff:::l UNIT 15 o a:: e ~ JAN 1990 n=66 It:::t/:J MAR 1991 n=27 u, o a:: w m ::E :::l 10 Z 5 0 .•..• U) I <:) U) t\I ..It) U) (') U) ~ I U) U) U) U) It) U) ••••• CD U) Q) It) It) U) It) U) U) .•.. I It) It) t\I (') It) •.... U) U) ~ DISTANCE FROM CENTER UNE (m) U) en CD 70 . MULE DEER TROUBLESOME til UNIT -so Q. :::l ~ 0 50 a:: n e JAN 1990 = 185 mFi:~:1 MAR 1991 n = 123" LL 0 40 a: w m ::E 30 :::l Z 20 ......... ~.---.. - .. 10 0 ..- It) <:) U)" It) t\I (') ~ U) U) (') It) I ..It) t\I It) It) I() U) It) • ~ <0 U) It) •.... U) It) CD Q) It) U) It) It) •.... CD It) It) ..It) Q) DISTANCE FROM CENTER UNE (m) Fiq. 1. Numbers of qroups of elk and deer observed at different distance intervals from the center line of line transects, Troublesome sub-unit, MIddle Park; -January -1990 and-March 1991. - �11 35 8J( 6.97 ~ -b--------------- TOTAL GROUP SIZE GROUPS 1990-1991 n =- 95 ~ 1-5 • 6-10 • 11-15 [] >16 25 fJ) 0.. ~ ·-·_-·--·---------------------------------f 20 CJ o Z 14.27 15 7.56 10 12.00 7.38 10.43 22.29 4.33 -------.---------.1><1----1 5 o 45-55 15-25 0-15 65-75 75-85 85-95 95-155 INTERVAL DISTANCE (M) Fia. 2. - Frequacy of .U: &rOup -a elistanc •. int.rvw for lin. trans.cts, Troubl.som. suh-uD1t, Middl. Parlt, . J_ary 1990 and March 1991. A_ras •. ala. of_all &rOUpsoba.rved within an int.rvaf -is shown above _th. to~al aroups· s.a in •• ch int.rval. . . 50 11.94 ELK GROUPS 1990-1991.. 40 , "~" ._.__ ._._. I- Z w 30 0 a: w 7.32 11.91 a.. 20 8.63 10 o CONIFER Fia. 3. -Fr.ciuac:y of .U: sroups -a January 1990 and March 1991. ASPEN habitat Av.ras. SAGEBRUSH OR OPENING MIXED CONIFER! ASPEN typea for lin. trans.cts, Troubl.som. suh-unit, Middl. Parlt, croup ala. for .ach habitat type is shown at th. top. �72 100 5.07 • TOTAL 1990-1991 GROUP SIZE GROUPS n •• 307 80 ~ 1-5 • 6-10 111 11-15 [J >16 ~ - -. _ .. "_"-_._--"---._._-"_ .. .." DEER 60 ~--.;><J.-.-.--------- ~- ... .. 9.06 ---------- 40 20 o 0-15 45-55 15-25 65-75 75-85 85-95 95-155 INTERVALDISTANCE (M) Fia. 4. FJ:eqa~ of d•• r aroups __ diatclc. iIlt.rvala for liD. trmaect., Troubl•• OIIIe .ub-un1t.. Middlti Pad:, J_ary 1"0 mel March1991. A_r •••• iz. of all aroup. ob•• rved within an int.rval b .hown move th. tot.al aroups ••••. iIl .ach iIlt.rval. ._ 10,000 MEANS +/- 95%CI ------_._-_ 8,000 ffiw ... __ .-r------ .-r- 6,000 C - o Z r- 4,000 2,000 _. , -=t=- o 1990 QUADS. Fia. S. 1990 TRANS. Populat.ion siz •• of d.er b•• ed upon quadrat.s and lin. . Yad:, January 1990 and March1991. - 1991 1991 QUADS. TRANS. t.rans.ct.s in th. Troublesom.sub-unit., Middle �73 Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o _ Project No. W-153-R-3 Work Plan No. Mammals Research· Multispecies Investigations 1A Job No. Animal and Pen Support Facilities for Mammals Research Period Covered: Authors: Personnel: July 1, 1990 - June 30, 1991. M. W. Miller, M. A. Wild, B. J. Maynard, and G. A. Stout. D. D. K. C. L. R. W. L. Baker, A. L. Case, R. B. Gill, C. Y. Irvin, B. Krabel, Magnuson, M. J. McArtor, J. K. Ringelman, T. R. Ritchie, Scott,· R. B. Snyder, M. R. Szymczak, A. N. Torres, Wagner, J. Whipperman, and S. M. Willis. Abstract . . The"·.coloradoDivision of Wildlife's Foothtlls Wildlife Research Facility (FWRF) maintained captive animals (up to"95 wild and domestic ungula~~s of 6 species and 103 migratory and upland game birds of 6 species) and facilities supporting 14 different mammalian and avian research projects. Routine animal care a~d facility maintenance programs were conducted as previously described. In accomplishing these ongoing activities, however, we attempted to develop ways to improve current facility management practices, particularly those that would increase efficiency and efficacy of feeding and maintenance activities related to research facility operations. All daily feeding and weekly cleanup duties associated with research animal maintenance were accomplished using about.25-30 hrs/wk of work-study labor; consequent~y, costs associated with these activities have been reduced by about 75%. A variety of modifications in feeding regimes and practices were also evaluated; elimi~ating supplement from adult bighorn maintenance diets, feeding cub~d alfalfa to elk, and using hay racks for feeding alfalfa hay appeared viable approaches for further reducing animal maintenance costs. Thirty neonatal ungulates were bottleraised Using established procedures; we also began evaluating modifications to improve our rearing protocol. Surgical treatment appeared to offer limited success in curing lumpy jaw in pronghorn based on preliminary evaluations; a Bacteroides nodosus vaccine produced antibody responses but failed to protect adult pronghorn from developing jaw abscesses. ��75 ANIMAL AND SUPPORT FACILITIES MAMMALS RESEARCH FOR Michael V. Miller P. N. OBJECTIVE To provide and ~intain popula~ions of captive animals and pen facilities to support Mammals and Avian Research Programs. SEGMENT OBJECTIVES 1. Main~ain and improve animal research and holding facilities. 2. Coordinate all rearing, training, maintenance, and research activities. 3. Maintain up to 15 elk, 40 mountain sheep, 30 pronghorn antelope, 15 mul~ deer, and 10 domestic cows in suitable health to perform required research experiments. 4. Conduct management experiments to increase efficiency and efficacy of feeding and maintenance activities related to research facility operations. .METHODS ANn MATERrALS Routine animal care and facility maintenance programs supporting new-~nd ongoing Terrestrial Wildlife Research Program projects were conducted ·as previously described. In accomplishing these ongoing activities, emphasis was placed on developing ways to improve current facility management practices. This year, we emphasized approaches for increasing efficiency and efficacy of feeding and maintenance activities related to research. facility operations. To this end, we worked toward improving management and operation of CDOW"s Foothills Wildlife Research Facility through the following: ANIMAL MAINTENANCE General: We established a labor force for daily feeding and care of research animals that relies wholly on workstudy students for routine feeding, cleaning, training, weighing, and other related duties. In order to estimate costs of maintaining captive wildlife at FWRF, a log of time spent feeding, stocking feed storage. areas, and cleaning pens was recorded. The time spent .in these activities was estimated each day by the person assigned to feed over a l7-day period. Approximations of time spent stocking and cleaning were also made during that period. NUTRITIONAL MAINTENANCE Feeding protocols: We evaluated utility of a feeding regime for elk based on calculated energy requirements for various age, sex, and reproductive classes. In addition,._we conducted pil_ot ~tudies to evaluate effects _9f dietary supplementation qn performanc~ of dam-ra~sed calves, as well as -efficacy of �76 high-energy wafers and alfalfa cubes as alternatives base diet for adult elk. to long-stem hay as a As a means of improving access to and reducing waste of alfalfa hay, we installed hay racks in bighorn, pronghorn, and mule deer pens. In addition, we began evaluating alternative feeding regimes for maintaining captive bighorn and pronghorn herds; modifications revolved largely around adjusting the amount of high-energy feed offered to adult animals to supplement their base. diets of longastem alfalfa hay. Bottle-raisin, neonates: Neonatal elk, mule deer, pronghorn antelope, and bighorn sheep wer~ hand-raised in 1990 and/or 1991 for use in various ongoing research projects. All neonates were bottle-raised using methods described elsewhere (Wild"and Miller 1991). In 1991, we began evaluating a modification of our established feeding protocol. This modification involved feeding evaporated milk at ad libitum rates only through 6-8 weeks of-age, and limiting daily milk consumption after that time to the average daily intake for the last 1-2 weeks of ad libitum consumption. Milk volumes offered were then gradually decreased until weaning at 90 days of age. Copper, in the form of CuS04 (100 mg/ml, 0.4 ml/day), was added to pronghorn milk in an attempt to prevent health problems that were attributed to copper deficiency in previous years. HEALTH MAINTENANCE General: We developed and implemented use of a system for recording daily health status_ for, research animals. That ~ystem wa~ evaluated and modified .throughout the year. •. Methods for treating and/or preventing lumpy Jaw in captive pronghorn~ We began studying the pathogenesis of pronghorn lumpy jaw using evaluations on 9 does (consisting of diagnostic skull radiographs and documentation of size and site of current lesions) to identify, describe and monitor progress of the disease. To identify the etiologic agent(s), we collected samples from peripheral and deep lesions from four does £or bacterial culture. To develop and evaluate a surgical protocol for treatment of lumpy jaw lesions, six does were paired based on radiographic changes and randomly assigned to treatment group. Treatment animals were anesthetized for surgical approach to apical tooth root abscesses on upper and/or lower premolars and molars. Apical abscesses were treated by trephining through the bone into the root abscess, then curetting to debride the site of infected bone and necrotic tissue. Extraction was used only in one case of extensive bone resorption around the tooth root with tooth instability. Sites were flushed with betadine solution, then saline, and left open to drain and heal by second intention. Ceftiofur (150 mg subcutaneously) was administered intraoperatively and again two days postsurgery. Control animals received no treatment. Animals that became moribUnd during the study period were humanely euthanized using intravenous injection of T6la. Gross necropsies and tissue collection for histopathology and bacterial culture were performed on these animals. We obtained 4-mon~~ postoperative skull radiographs from treatment and control .. pronghorn· to .. aid in prelimi~ry evaluation of -surgical treatment. �77 In a related study, we began testing the efficacy of a killed Bacteroides nodosus vaccine (Footvaxa) in prevention of lumpy jaw in unaffected pronghorn. Prevaccination, we collected blood from all pronghorn for determination of titers to Bacteroides sp. One affected doe (SF) was initially vaccinated subcutaneously in the neck with 1 m1 vaccine using aseptic technique to test safety of the vaccine in pronghorn. Subsequently, four does and two bucks were vaccinated and three control castrates received 1 m1 sterile saline using the same procedure. Two vaccinated animals (236 and MI) were housed with affected does; 4 others (JJ, LA, ~I and BD) remained unexposed to affected animals. We collected blood from all pronghorn again about 10 weeks postvaccination. Plasma and sera were stored at -40 C until assayed. Serum samples from clinically affected, unaffected vaccinated and unaffected, assumed unexposed free-ranging pronghorn were submitted to Greg Ferrier at the Regional Veterinary Laboratory, Victoria, Australia. Titers to B. nodosus were determined using an enzyme-linked immunosorbent assay (ELISA) previously developed for sheep (Ferrier et al. 1988); pilot studies had previously revealed that anti-sheep/goat IgG could be used as a conjugate for detecting pronghorn antibody. In addition to serologic studies, vaccinated pronghorn were observed daily for development of jaw abscesses. FACILITY MAINTENANCEjREPAIRS/IMPROVEMENTS A vaxiety ~f scheduled and unscheduled maintenance and repair activities were necessary to.support faci1ity·ope~ation and ongoing re~earch.programs. As with appr'oaches to modifying our ANIMAL MAINtENANCE program, emphasis was placed on improving current facility man~gement practices through preventive maintenance projects and high-quaiity repairs to existing facilities~~ A "project board" system was implemented for identifying and assigning repair and maintenance tasks at FWRF. We continued to modify and improve that system throughout the year. RESEARCH PROJECTS .Facility operations supported offered support for pilot studies, special studies, and research experiments that were initiated, conducted, or continued using FWRF animals and facilities throughout the year. RESULTS AND DISCUSSION ANIMAL MAINTENANCE Estimated time required for accomplishing routine animal maintenance activities per individual animal was generally less when the number of animals per pen was large, but the total time required for accomplishing these activities increased with increasing numbers of animals. Estimated time spent in these activities was quite consistent among individual caretakers on a dayto-day basis. Time required for feeding, stocking feed storage areas, and cleaning pens averaged about 2.2 hrs/day or 15.5 hrs/week (Table 1). Estimates of time required for the specific duties described are given in Table J.. �78 Table l. Estimated time (minutes) required for accomplishing care activities at FWRF. daily animal A!I:!;;1v1~ Number of Individuals Feeding Stocking Cleaning Total Time Elk 15 25.7 4.3 6.6 36.6 2.4 Sheep 28 22.9 4.3 8.6 35.8 1.3 Goat 1 3.9 0 2.1 6.0 6.0 Pronghorn 14 16.3 4.3 4.3 24.9 1.8 .Deer 10 11.3 2.1 2.9 16.3 1.6 Cow 1 3.8 0.7 1.4 5.9 5.9 43 4,5 0 2.9 7.4 0.2 112 88.4 15.7 28.8 132.9 1.2 Species Waterfowl Totals All daily feeding and weekly clean-up accomplished using about 25-30 hrs/wk costs associated with these activities $207/wk for Utility Worker I labor to Time/ An./day duties, as well as most repairs, were of work-study labor. Consequently, have been reduced by about 75% (from $47/wk for student labor). -NUTRITIONAL MAINTENANGE Feeding protocol's: Preliminary analysis of performance data suggested the origi!tai feeding regime developed for elk underestimated maintenance-=. requirements for both nonlactating and lactating (particularly lactating) cows. Based on this assessment, we recalculated energy requirements andadjusted the feeding regime accordingly. Its evaluation is in progress. Supplemented elk calves showed somewhat higher average daily gains than calves fed alfalfa alone (0,40 and 0.35 kg/day for supplemented vs. 0.35 and 0.30 kg/day for unsupp1emented), Feeding high-energy wafers ad libitum caused digestive upset (as indicated by anorexia, cribbing, and changes in'defecation patterns) in adult elk; changing their diets to commercial alfalfa cubes eliminated these problems. Alfalfa cubes offered an alternative experimental foodstuff that was readily consumed, easily quantified, and without apparent digestive complications in short-term feeding trials using adult elk. We plan further evaluations in both elk and bighorn sheep. Hay racks installed in bighorn, pronghorn, and mule deer pens appeared to improve access to and reduce waste of alfalfa hay; this approach was particularly successful for feeding bighorns: subjectively, modification of hay feeders, combined with restriction of supplemental feed (see below) appeared to reduce their hay waste by about 90%. For both bighorn sheep and pronghorn, our feeding regimes have called for providing ad libitum quantities of alfalfa and supplement in recent years to assure all individuals were in optimum condition. This approach has proven both wasteful and detrimental. We eliminated supplement from daily diets of adult bighorns in mid-November; after 1 month of restricted feeding, their average weights were unchanged, and feeding efficiency had improved dramatically (see above). We continued monitoring responses and adjusted �79 diets as energy requirements increased during late gestation. This feeding regime had no apparent detrimental effects on lamb birth weights or survival. Our results suggest supplementation is unnecessary for adult bighorn sheep through most of the year. Using a similar approach, we restricted the amount of supplement offered to pronghorn. In late October, we began feeding them quantities of high-energy pellets just sufficient to meet average daily maintenance requirements. Our goals with this modified regime were to increase alfalfa consumption and reduce fatness in adult does. The new feeding program appears to have stabilized average doe weights since November; in contrast to this year's weight dynamics, the same individuals gained weight during November-December 1989. As with the bighorn trial, we continued monitoring responses and adjusting diets to meet seasonal changes in maintenance requirements. Several older does failed to maintain base body weights late in gestation, as reflected in postparturient weights, suggesting the calculated ration of supplement was insufficient to sustain both maintenance and fetal growth requirements. However, we observed no apparent adverse effects on birth weights or survival of pronghorn fawns. A reevaluation of this feeding regime is planned for next year. Bottle-raising neonates: We successfully hand-raised 2 deer fawns and 2 elk calves in 1990. In 1991, a total of 26 neonates were being bottle-raised by late June; these included bighorn lambs (4 male, 3 female), elk calves (2 male, 2 female), mule deer fawns (2 male, 2 female), and pronghorn fawns (5 male, 6 female) were born at the facility. Aside from 2 elk calves, 2 deer fawn.s.,and 1 pronghorn fawn, all necnaces were· born in capt·ivity at FWR¥. Birth dates ranged,from April·28 (bighorn) through .June 28 (pronghorn) (Table 2),-and varied by ·species. Average daily intakes and average weights on a weekly·basis for each spe~ies are shown in Figs. 1-2. Table 2. Birth dates and mean weights for neonatal ungulates born at FWRF dUIi.ng Ha:£-J:une},991. BIRTH DATES BODY WEIGHT (kg) SPECIES N bighorn sheep 7 28 Apr elk 4 17 May - 28 Jun (10 Jun) 21.0 pronghorn 11 4 Jun - 26 Jun (16 Jun) 2.9 mule deer 4 15 Jun - 19 Jun (19 Jun) 3.1 RANGE (MEAN) 16 May (9 May) 5.0 Minor neonatal health problems varied among the four different species. Mild viral enteritis attributed to rotavirus occurred in elk calves in both 1990 and 1991. Clinical signs included diarrhea, slight depression, and anorexia (0 - 50% of normal milk intake). In elk calves, this disease appeared to be self-limiting without treatment -- milk intake returned to normal within 1-7 days, and diarrhea resolved within 1-2 weeks. Captive-born mule deer (n-2) and pronghorn (n-2) fawns developed diarrhea within 2-7 days of birth. Affected animals with fecal pH >7 and/or body temperature >103 F were treated with injectable or oral trimethoprim-sulfa; mule deer fawns were also provided with electrolyte solution in bo~ls. These ·cases resolved within 1 week. Six �80 of 7 hand-raised bighorn lambs developed pneumonia by 6 weeks of age. (See WP2A,J4 for additional details.) Affected lambs decreased milk intake and weight gains as pneumonia developed, but these rates returned to near-normal within 1-1.5 weeks of initiating antibiotic therapy (Wild and Miller 1991). To date, no mortalities have occurred in association with any of these health problems. Limiting milk consumption at 6-8 weeks was implemented in an attempt to more. closely approximate intakes and weight gains observed in dam-raised neonates.· Milk consumption of dam-raised ungulates peaks at about 3 weeks of age (Robbins et al. 1981), at which time the young begin to consume more dry matter. Our existing protocol does not limit the neonates' milk intake, and it is conceivable that excessive milk intake could delay the surge in dry matter intake for our bottle-raised neonates, consequently depressing their growth rates below those of dam-raised individuals. Under our approach, limitation was delayed until 6-8 weeks of age to allow neonates to fully accept bottle feeding .. Only bighorn lambs had reached 6-8 weeks of age by June 30. and they had not been on the limited intake schedule long enough to evaluate its effect on performance. We plan to continue monitoring weights of all neonates both before and after intake limitation to evaluate this modification of our rearing protocol. A new technique was used for starting reluctant calves on the bottle. On separate occasions, 2 elk calves that resisted bottle-raising were put in a pen with· a socialized calf at feeding time. The recalcitrant calves would try to suckle from the socialized calves; the feeder could then place a bottle under the socialized calf for the ~ther to take .. This "surrpgate mother" technique was used only at scheduled feeding times. and only after the feeder had tried to promote suckling on her own, Because this technique could hamper imprinting on the human feeder, it was used only to get calves startea on the~ bottle. After-2-3 days, the calves were no longer allowed contact with their "surrogate mothers," forcing them to take the bottle from their human feeder. This approach appeared to be an effective means of preventing 7-14 day delays in initiating bottleQnursing in elk calves previously endured at FWRF. HEALTH MAINTENANCE General: Our system for recording daily health status for research animals markedly improved communications, detection, and treatment of animal health problems at FWRF. Overall, captive wildlife maintained at FWRF remained healthy throughout the year. In addition to ongoing problems with lumpy jaw -inpronghorn and pasteurellosis in bighorn described elsewhere, chronic wasting disease was confirmed in a SQyear-old elk cow (B86) in May; this represents the second case since our 1985 attempt to eradicate this disease from captive cervids at FRWF. Methods for treating and/or preventing lumpy jaw in captive pronghorn: Examination of captive pronghorn does revealed that 3 does (203, 236. NI) had no visible soft tissue abscesses, and 6 had 1-4 soft tissue abscesses each. Skull radiographs from all animals showed mild to moderate dental changes, including periodontitis, widening of apical germinal buds (suggestive of early abscesses), apical tooth root abscesses, osteomyelitis, tooth loss, malapposition of teeth and retained deciduous teeth. Of 27 root abscesses detected radiographically, 18 were associated with mandibular teeth. The second molar was mos~ frequently-involved on the lower arcade; however, the �81 fourth-premolar and first and third molar were all commonly abscessed. On the upper arcade, the fourth premolar was most frequently abscessed; the third premolar and first and second molar were involved less frequently. Two 27month-old does and one 39-month-01d doe had retained deciduous premolars permanent premolars usually erupt at 27-29 months of age in pronghorn. Radiographic abscessation pronghorn. attributable findings suggested that a progression from periodontitis to root to osteomyelitis may occur in the pathogenesis of lumpy jaw in Initiating factors for periodontitis remain unclear, but may be to abnormal tooth eruption and/or wear or gingivitis. Preliminary culture results revealed presence of Actinomyces pyogenes, Pasteurella multocida, Proteus mirabilis, Bacteroides sp. and Fusobacterium necrophorum in lesions associated with abscesses. Although these bacteria could be part of normal oral flora, presence in high proportions could lead to colonization and infection. Sanitation, high animal density and/or contact with infected animals may contribute to increased bacterial exposure, while diet form and composition, oral lesions and/or immunocompromise may increase the possibility of bacterial colonization. We performed surgery on 1 pilot case (SF) and 3 treatment cases (202, 231 and JO). We treated 2 maxillary and 8 mandibular root abscesses identified on radiographs, and 1 maxillary lesion identified by a draining tract. In addition, 1 lower molar was extracted (202) due to extensive bone resorption around the root, exposing it to the skin surface. All does recovered uneventfully postoperatively, with the exception of 202: she developed myiasis -at th~ site of molar extraction and ~emained ~epressed for about 10 day~. Although treatment with betadihe solution flush, KRS~ fly spraY'and 3 additional doses of ceftiofur appeared to resolve this problem, 'she subs~quent1y developed bronchopneumonia and died about 10 days postsurgery. In addition, 1 control animal (SB) developed severe necrotizing aspiration pneumonia refractory to antibiotic therapy; she was euthanized about 2 weeks after study initiation. . Preliminary evaluation of radiographs taken 4 months after surgery revealed that 1 or more lesions appeared to be healing in each of 3 treatment animals; however, 1 animal (231) still had 1 active tooth root abscess and another (SF) had 2. Healing was evidenced by formation of bony callous where lytic bone was surgically removed. These observations suggest that surgical treatment of tooth root abscesses can resolve the lesions, especially if lesions are acute. However, lumpy jaw itself may not be resolved in these animals because other tooth roots may subsequently be independently infected and require additional surgery. Skull radiographs and possibly surgery may be indicated if repeated attempts to manage abscesses by draining and flushing are not effective or result in chronically draining tracts. No adverse reaction to the killed B. nodosus vaccine was observed in the first doe vaccinated (SF). However, al16 study animals vaccinated subsequently developed firm swellings at vaccination sites; 2 of these drained pus, but subsequent culture results revealed these were sterile abscesses. Lesions resolved without treatment in 6-12 weeks. No reactions occurred in 3 controls injected with sterile saline. Despite these localized reactions, Footvax~ appeared to be safe in pronghorn. �Estimated antibody titers to B. nodosus did not appear to differ between clinically affected and unaffected animals; however, postvaccination titers were markedly higher than those in any unvaccinated animal (Table 3). We may not have detected titers in affected animals for any of several reasons: 1) pronghorn may harbor a different antigenic strain or species of Bacteroides than that used for the vaccine or ELISA antigen; 2) Bacteroides sp. organisms may be present in low numbers or "walled off" and protected from host immune response; 3) natural titers may be occur upon initial infection but be short~ lived. Table 3. Serologic affected pronghorn. History Unaffected Unexposed· Vaccinated Pre titers to B. nodosus in unaffected, Animal ID 1 2 3 236 LA NI JJ BD ;MI vaccinated Titer History Animal ID 150 150 330 Exposed 233 234 238 246 180 360 310 560 190 190. Postb 236 LA NI JJ. BD MI and Titer 220 350 190 290 3300 11760 7020 20000 80000 133000. Affected JO SL SF 202 SB 231 203 270 ·180 150 310 250 400 190 ·Freemranging pronghorn bSerum collected about 10 weeks after initial vaccination Jaw abscesses occurred in both vaccinated bucks (BD, MI) in February, 1991. Actinomyces sp., Fusobacterium necrophorum, Fusobacterium sp. and Bacteroides sp. were cultured from these abscesses. Soft tissue lesions resolved within 1 week of draining and flushing the abscesses; however, bony proliferatIon is apparent on BD's mandible. Four does remained clinically unaffected until June, when #236 showed signs of a small maxillary abscess that may have developed and ruptUred. We plan to continue monitoring vaccinated animals for development and progression of lesions to further evaluate protective ability of the measured antibodies. �H3 FACILITY MAINTENANCE/REPAIRS/IMPROVEMENTS Significant maintenance/repair/improvement year included: projects completed at FWRF this - installing drainage ditches in the west alleyway and upper bighorn pens; - cleaning, sterilizing, and regraveling the common area east of the isolation pens, installing new gates to improve access to that area, and installing cutoff gates to improve animal handling capabilities in this· area; . - staining alleyways and shelters in the east facility to reduce weather damage; - completing a facility-wide clean-up -- numerous unused items were removed to increase storage space for research materials at FWRF; - installing new feeding structures in elk paddocks, and constructing and installing wooden or steel pipe hay racks in bighorn, pronghorn, and mule deer pens; - building a feed storage sheds and shelters in mule deer and pronghorn pens; - weather-proofing the hay storage shed; - adding new latches and completing other improvements for both east- and west-side alleyways; - preparing a SOP listing all procedures undertaken in our annual facility-wide winterization process; - preparing a plan for expansion of hoofed-stock paddocks; - rebuilding and fortifying the elevated ramps entering the digestion cages; .".. buildirig and" ins.ta:Uing new· dcczs- in the west side· scale room, freezer room: and primary feed storage shed;· -. _.:_ installing plywood flooring in the east side primary feed storage ahed ;> - installing wing fences and visual barriers in pronghorn and mule deer pens; . " - rebuilding the lumber storage rack; - constructing and installing a new facility for weighing and handling pronghorn and mule dee~; - planting windbreaks along the main road and creek bottom. RESEARCH PROJECTS In addition to ongoing facility management experiments and improvements described above. the following (listed in no particular order of importance) pilot studies, special studies, and research experiments were initiated, conducted, or continued using FWRF animals and facilities this year: - New models of the functional response in vertebrate herbivores: the role of plant availability and animal morphology -- Spalinger, Hobbs, Wunder, and Gross; - Relative effectiveness of repellents for reducing feeding by elk -Andelt, Baker, and Burnham; - Use of behavioral observations to estimate conception and recurrent estrus in captive elk -- Ritchie, Baker, and Lehner; �84 - Effects of plant and free water on voluntary feed intake in bighorn sheep -- Anderson, Hobbs, and Baker; - Development of an experimental model to reproduce clinical carfentanil renarcotization in elk -- Miller, Lance, Wild, Dunn, and Tipton; - Experimental evaluation of a sustained-release formulation of naloxone hydrochloride for preventing carfentanil renarcotization in elk -Miller, Lance, Wild, and Dunn; - Effects of sample handling on measured blood progesterone captive elk -- Freddy, Miller, and White; - Pronghorn spectral sensitivity levels from -- Maynard, Lehner, Gill, and Roberts; - Epizootiology of pasteurellosis in captive Rocky Mountain bighorn sheep -- Miller, Wild, Mills, and Snipes; - Seasonal changes in fecal cortisol excretion in captive Rocky Mountain bighorn sheep -- Miller and Ritchie. - Field dose determination of medetomidine-ketamine sedation of cervidae with reversal by atipamezole Wild; - Nutritional combination for -- Miller, Lance, and ecology of sage grouse during winter -- Remington; E~feet~ of'pregruincy on intake and digest~Dility and MagnUson .. LITERATURE in captive elk :"-.Baker CITED Wild, M. A., and M. W. Miller. 1991. Bottle~raising wild ruminants in captivity. Outdoor Facts 1/114, Colo. Div. Wildl., Denver. 6pp. Robbins, C. T., R. S. Podbielancik-N~rman, D. L. Wilson, and E. D. Mould. 1981. Growth and nutrient consumption of elk calves compared to other ungulate species. J. Wildl. Manage. 45:172-186. �85 Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o_ Proj ect No. 0 __ Mammals Research ..:;W:..;;..• 1.&5"",3.;;.,i-R!;l:,-...;:4~ __ Work Plan No. lA Multispecies Job No. 3 Mammals Research Administration Period Covered: Author: Investigations July 1, 1990 - June 30, 1991 0 R. B. Gill Personnel: R. B. Gill, L. E. Lovett Abstract Duri~g the 1990-91 segment members of the Mammals Research staff produced the following: 0 ;dr~f~s of 5 management analysis repprts; ~oarticres in professional journalsfbooks; -:7 articles in professional sympos La ; 1 agency technical publication; and 2 non-tachnical 0 publications. Staff members served on a variety of management task forces and steering committees and produced drafts of 5 species management analysis reports. The Mammals Research staff exceeded all of the production objectives for Federal Aid Prooject W-153-R-4 and expended only 95% of the resources allocated to accomplish those objectives. ��87 HAHKALS RESEARCH ADMINISTRATION a. Bruce Gill P.N. OBJECTIVE Administer research within the Mammals 1 and·2 Research Units for the highest productivity at the lowest cost. SEGMENT OBJECTIVES 1. Assign and supervise the research of 6 Wildlife Researchers. 2. Assign and supervise secretarial and clerical work of 1 Senior Secretary. 3. Lead the development and implementation of statewide species management plans. 4. Assist in planning of Rocky Mountain Arsenal Watchable Wildlife Showcase. RESULTS ~ DISCUSSION During the FY 1990·-91 segment; I prepar~~_'performance plans, supervised, and· During -.the evaluated the technical performance 11 Wildlife Researchers. segment these employees produced the following: drafts of 5 management analysis reports; 6 articles in professional journalsfbooks; 7 articles in professional symposia; 1 agency technical publication; and 2 non-technical publications. In addition, I co-authored 4 manuscripts which have been accepted for ·publication in 1991-92 pending revision and co-authored 3 manuscripts which currently are in internal peer review and will be submitted to professional journals for acceptance in FY 91-92. Members of the Mammals Research staff served on the Division's Habitat Partnership Steering Committee; the Commercial Wildlife Parks Working Group; the Rocky Mountain Arsenal Watchable Wildlife Steering Committee; the Mountain Sheep and Mountain Goat Auction Project Selection Committee. Mammals Research staff produced a draft Problem Bear Management Administrative Directive; policy level objectives for the Long Range Plan update on black bears; worked closely with the Habitat Section and the Public Services Section to develop solutions to the San Juan grizzly .bear controversy; developed a Mission Statement and alternative Program Structures for DNR; worked closely with the mountain lion symposium committee to organize ana evaluate the-Mountain Lion Symposium and develop implementation recommendations for the Director's consideration.· �88 The Mammals Research staff produced drafts of 5 management analysis reports: deer, elk, pronghorn, mountain sheep, and trapping; developed a second survey of public attitudes concerning Colorado's black bear management program which would include only those likely to vote; produced a draft of a Black Bear Technical Bulletin on schedule for release at the September, 1991, Wildlife Commission Meeting; developed successful proposals for "decision item" -funding concerning lynx status survey, kit fox status survey, and development of a black bear inventory process; developed 5 research proposals: a) ef!ects of early hunting on the distribution of elk in Northwestern Colorado; b) the effects of disturbance by recreationists on the Arkansas River mountain sheep population; c) development of fertility control techniques to manage unhuntable deer popUlations; d) experimental evaluation of mountain sheep transplanting and disease management; e) effects of density on dispersal of pronghorns in Middle Park Colorado. During FY 1990-91, we were allocated $1,194,056 to accomplish the objectives of Federal Aid Project W-153-R-4. We were unable to match the allocation against real expenditures because the Division's COFRS system was unable to produce budget status reports for all of FY 199091. However, the Mammals Research in-house computerized "checkbook" accounting system indicated we exceeded the production objectives for FA Project W-153-R-4 at a total cost of $1,131,324 or at 5% under budget. Prepared by ~~.~.~w9 R~aGiil -.- Wildlife Research Leader �0;;1 Colorado Division of Wildlife Wildlife Research Report July 1991 JOB FINAL REPORT State of ~C~o~l~o~r~a~d~o~ _ Project No. W-153-R-4 Mammals Research Work Plan No. lA Multispecies Investigations Job No. 4 Wild Ruminant Forage Selection Dynamics Period Covered: Author: July 1, 1990 - June 30, 1991 B. J. Maynard Personnel: B. J. Maynard, P. N. Lehner, R. B. Gill Abstract A Master of Science Thesis entitled: Spectral Sensitivity of Pronghorn (An~ilocapra americana) was completed-under the supervision of Dr. P. N. Lehner of the Department of Biology at Colorado State University, Fort Collins, Colorado-80523. The abstract of that thesis follows: The spectral sensitivity- of pronghorn, Antilocapra americana, was - examined by the use of corneal ~lec~roretinography and with a two-choic~ behavioral discrimination procedure. Electroretinography revealed a ~rk-adapted curve of the typical shape with peak sensitivity around 550 nm. _Behavioral discrimination tests confirmed that spectral sensitivity decreases rapidly between 700 and 750 nm. Pronghorn failed to respond to stimuli of 750 nm and longer wavelengths under both procedures. Prepared by _._A.-;;, ...•.••• A ~""",",N J~A,/Jn",,+1--' •...••. ~~ Lr.=.;. A=-->o' ~~ Master's Candidate IJ •,'--•... _ ��Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~ _ Project No. W-153-R-2 Mammals Research Work Plan No. lA Multispecies Investigations Job No. 5 Consulting Services for Mark-Recapture Analysis Period Covered: Author: July 1, 1990 - June 30, 1991 G. C. White Personnel: R. M. Bartmann, D. Saltz, L. H. Carpenter, R. B. Gill, T. D. I. Beck Abstract Progress towards the objectives of this job include: 1. A manuscript s~arizing ~he results of the Piceance Basin deer populatiQn studies has been accepted for publication as a WildlifeMonograph of The Wildlif~ Society. 2. A study of compensatory effects of harvest on the Piceance Basin mule deer population has been designed, with experimental harv~sts in December, 1989 and 1990. Radio collars to monitor over-winter survival of fawns were placed on the animals during November, 1989 and 1990. 3. The TRAPMARK database has been developed to store records of marked animals. Users are able to enter data, and to interrogat,e the database for potential radio frequencies or neck collar colors that could be used in a specifi~!igeographic area. 4. Consultation has been provided in the design and analysis of evaluating the validity of harvest estimates of elk and deer in North Park. 5. Consultation has been provided on sampling and design and analysis procedures to estimate crayfish biomass to aid in river otter recovery research. ��93 CONSULTING SERVICES FOR MARK-RECAPTURE ANALYSES G. C. White . P. N. OBJECTIVES Model and simulate population estimates of deer, elk, mountain sheep, and mountain goats with mark-recapture methods. SEGMENT OBJECTIVES Evaluate correlations of over-winter survival rates of wild mule deer (Odocoileus hemionus) fawns with levels of urinary cortisol:creatinine and urea nitrogen:creatinine ratios in 14 tame yearlings. RESULTS AND DISCUSSION Determining population condition is critical to the sound management of wild populations. Although never clearly defined, 'population condition' generally refers to the ability of a population to function in a deteriorating environment in terms of survival and birth rates. Population condition has been assessed by a variety of indices. Most fall under one of 3 categories .(Hanks 1978): (1) physiological condition of individual animals determined by .fat deposits, bl-ood parameters,' body' growth, etc., (2) demographic' parameters such ~s survival and fecundity of each sex and age group in the populC!tion, and (3) behavioral attributes such as feeding strategy and the rate and quality of social interactions. Physiological indices of popUlation condition are the most commonly investigate~ (Franzmann 1985). Nonetheless, as Nisbet et al. (1989) point out, these indices have a fundamental problem - they are measured at the level of the individual animal, while the manager's primary interest is at the population level. It is often assumed 'that, taken collectively, individual animal mea$urements can depict the condition of the population, although there are few data to support this hypothesis (Hanks 1978, Nisbet et al. 1989). Cortisol and urea nitrogen are physiological parameters recently used as animal condition indices (Saltz and White 1991a, DelGiudice et al. 1989). Cortisol is a glucocorticoid that mobilizes energy reserves in animals experiencing chronic stress (Stephens 1980). As such, it is assumed to reflect the net instantaneous energy loss by an animal. By contrast, urea nitrogen is a metabolite that is positively correlated with protein intake (Franzmann 1985) and is, therefore, indicative of diet quality_ However, this relation is reversed under extreme conditions (Brown 1984). Both cortisol and urea nitrogen can be measured in serum or as ratios to creatinine in urine (Franzmann 1985, Miller 1991). In a recent study, Saltz and White (1991a) investigated the effects of different environmental conditions' on the levels of urinary cortisol:creatinine and urea nitrogen:creatinine in tame mule deer. The tame deer wintered in two fenced pastures stocked with wild deer at high and low densities. Cortisol:creatinine ratios increased with population density and as winter progressed, and were lower in animals entering the winter with greater body mass. Urea nitrogen:creatinine ratios decreased as winter �94 progressed and increased with cortisol levels. In a parallel study conducted in the same pastures (Bartmann et al. 1991), fawn survival decreased with population density. Thus, we hypothesize that both cortiso1:creatinine and urea nitrogen:creatinine are reliable indices of mule deer population condition. The purpose of this paper is to test these hypotheses. We do so by correlating cortisol:creatinine and urea nitrogen:creatinine ratios described by Saltz and White (1991a) with the fawn survival rates described by Bartmann et al. (1991). METHODS The study was conducted in fenced pastures just east of the Colorado Division of Wildlife Little Hills Experiment station in northwestern Colorado. Two pastures (66 and 169 ha) were stocked with wild mule deer during NovemberDecember 1987, at high (1.33 deerjha) and low (0.44 deerjha) densities (Bartmann et al. 1991). The stocked populations consisted of 50 radiocollared fawns in each pasture and the number of adults needed to achieve the desired densities. Radios were equipped with mortality sensors. The fawns were radio monitored on a daily basis between December 1987 and mid-April· 1988. Fawns with collars that emitted mortality signals were located, and the cause of mortality determined. A detailed description of the pastures, trapping, and collaring techniques, can be found in Bartmann et a1. (1991). Urine samples were obtained from 14 hand reared mule deer yearlings. Yearlings were paired based on sex and body'mass, and individuals from each pair ~ere assigned randomly to the high- and low-density pastures·. They were place~ in the pastures November 18, 1987, and except tor token amount~ of .pellet feed (Saltz and White 1991a) survived by feeding on existing native vegetation. Urine was collected by placing the yearlings in specially built cages located in the pastures. An effort was made to collect one sample per yearling per week. Levels of urine cortisol and urea nitrogen were determined in relation to urine creatinine levels (Berman et al. 1980). Analyses for cortisol were radioimmunoassay procedures '(Olson et al. 1981), and were validated by .para1lelism and quantitative recovery (Saltz and White 1991b). Analysis for urea nitrogen was a colorimetric procedure using a Gilford spectrophotometer. Creatinine levels were determined by the Jaffe (1886) procedure with an Hitachi analyzer. A detailed description of the urine collecting methods, urine analysis and assay validation can be found in Saltz ~nd White (1991a,b). All statistics were performed and are presented using the ratio of micrograms cortisol per milligram creatinine (cortisol:creatinine ratio), or milligrams urea nitrogen to milligrams creatinine (urea nitrogen:creatinine ratio). Mean cortisol:creatinine ratio and urea nitrogen:creatinine ratio were determined weekly for each pasture. Weekly survival rates of radio-collared fawns were calculated as the number of fawns surviving at the end of the week divided by the number alive at the beginning of the week. Data were analyzed using logistic regression procedures (PROC CATMOD, SAS 1987), with weekly survival rate as the dependent variable. We ran separate analyses with weekly means of cortisol:creatinine as the predictor, and weekly means of urea nitrogen:creatinine as the predictor. Survival was weighted by number of animals alive at the start of the week. and data were blocked by pasture (density). Because higher cortisol:creatinine and urea nitrogen:creatinine ratios, as well as lower survival rates, were associated with the higher density pasture (Saltz and White 1991a), a co1inearity exists between the �95 predictors and blocking factor. Furthermore, when running the regressions on the combined data from both pastures, significance may be due to pasture effects alone and not to fluctuations within each pasture. To determine if weekly survival rates were correlated to weekly means of cortisol:creatinine or urea nitrogen:creatinine, we ran additional regressions using data from each pasture separately. Results were considered significant at f < O.OS. RESULTS A total of 19 weeks of survival and urinary data were collected between December 7, 1987, and April 15, 1988. Data from the two smallest yearlings were excluded from our analyses after the high density yearling developed an abscess and was subsequently artificially fed. By the 17th week all fawns in the high density pasture died. Consequently, we ran logistic regressions on the weekly survival from both pastures for the first 17 weeks only. Cortisol:creatinine in the high density pasture increased throughout the winter while survival decreased (Fig. 1). By contrast, ·survival and cortisol:creatinine response patterns in the low density pasture were more ambiguous (Fig. 2). There was a mild decline in survival throughout the winter with a possible increase towards the end of the winter. Cortisol:creatinine levels increased at the beginning of the winter and remained roughly constant until the end of the winter when they declined to their lowest levels. Initially, we ran a full model logistic regression on suryival with cortisol:creatinine and pasture density as·predictors. We found no significant interaction (f - 0.1007) between the predictors and therefore removed the interaction term. In the reduced model, the effect of �96 mGH DENSITY PASTURE 1.0 1.0 0.11 ,I• -= ---=.- 0.9 <lie - = IE •• 0.6 &l 0.5 8 0.4 ~: --I ---_. ---W === =~ == = === = I i 0.9 0.8 0.7 til 0.6 ~ 0.5 ~ 0.4 ~ 0.3 0.2 0.1 ~ O.~ o Figure 1. Fawnsurvival (_-..-) and yearling urinary cortisol: creatinine - -) and urea nitrogen:creatiniue (••••• ) levels in the high density pasture. -(- - �97 LOW DENSITY PASTURE 0.11 1.0 1.0 0.9 0.10 0.8 0.09 0.7 fIl U 0.6 ~ 0.5 Z o 0.4 0.08 ~ 6 0.6 ~ 0.07 0.5 ~ 0.06 0.4 ~ ~:~8 0.3 O.OS 0.2 ~ 0.1 ~ 0.04 0.1 o o I DEC 87 II JAN 88 II FEB 88 IIMAR 88 II APR I Figure 2.· Fawn survival (---) and yearling ur1nary cortisol:creatinine .- -) and urea nitrogen:creatinine (••••• )-~evels in the low density pastur-e. (- cortisol:creatinine was highly significant (f <0.0001), but pasture density was not (f - 0.5087). When regressions were run separately for each density we found a highly significant effect (f < 0.0001) of cortisol:cr~atinine on survival in the high density pasture, but no significance in the low density pasture (f - 0.8830 for 17 weeks, and f < 0.6793 for 19 weeks). Urea nitrogen responses were similar in both pasture, declining at the onset of winter and increasing at the end. In the full regression model the interaction between the two predictors (urea nitrogen:creatinine and population density) was not significant (f - 0.4914). In the reduced model, urea nitrogen:creatinine was significant (f - 0.0074), as was population density (f - 0.0020). Regressions run separately for each pasture produced a significant effect (f - 0.0204) of urea nitrogen:creatinine in the high density pasture, but no effect in the low (f - 0.2832 for 17 weeks, and f 0.7835 for 19 weeks). DISCUSSION AND MANAGEMENT IMPLICATIONS If an index of population condition is to be of any practical use, it must be linked to the survival and/or birth rates of the population. In this study we had no data on adult survival and reproquctive success, and compared our indices with fawn survival only" Neve rrheLess , juvenile survdva'l,is the major factor in the dynamics of mule deer (Connolly 1981), .and other mammalian populations (Hanks 1978). To our knowledge, this is the first time a �98 physiological index has been successfully correlated to a component of population condition. Our study was carried out in only 2 pastures with different densities. Thus, because there are no pasture replicates, results are limited to these pastures alone. Although the differences in survival, cortisol: creatinine, and urea nitrogen:creatinine ratios between the 2 pastures are real, their applicability to other areas should be viewed with caution. Both cortisol:creatinine and urea nitrogen:creatinine were correlated to fawn survival. In the urea nitrogen:creatinine model both predictors (urea nitrogen:creatinine and pasture density) were significant. By contrast, we found no effect of pasture density in the cortisol:creatinine model. This suggests cortisol:creatinine accounts for density effects while urea nitrogen does not. We therefore conclude that cortisol:creatinine is superior to urea nitrogen:creatinine as a predictor of population condition. This is in agreement with results presented by Saltz and White (199la). The lack of significance in regression of cortisol:creatinine on fawn survival in the low density pasture may be the result of 2 factors: (a) Minor changes in mean survival and cortisol: creatinine 'in relation to the variance. This suggests that under low stress levels, the noise in the data overshadows the actual effects, rendering this technique questionable u~der such conditions. (b) A drop in cortisol:creatinine towards the ,end of the winter that was not associated with_a rise in survivorship. This may be due to correlating a physiological response of yearlings with the survival of fawns. Yearlings may be able to recover from winter starvation more quickly than fawns, causing the above discrepancy. Regressions of just the first 15 weeks of data in the low density pasture did produce a significant (f - 0.0446) effect of cortisol: creatinine, but not of urea nitrogen:creatinine (f 0.3525). Cortisol is a mobilizer of energy reserves needed for survival in a deteriorating environment. Thus, cortisol is not a direct indicator of condition, but rather an index to the rate at which an animal's condition is deteriorating. Physiologically, elevated blood levels of cortisol are defined as stress (Stephens 1980). Ecologically, stress may be described as any environmental change that acts to reduced the fitness of an individual Koehn and Bayne (1989). Although widely used in ecological studies, the term still draws substantial criticism. The debate over the term is not over its definition, but rather whether the term should be used at all in ecology (Grime 1989). Data presented in this paper demonstrate that physiological stress is in fact correlated to fitness; and, therefore, its use in ecology is justified. Urinary cortisol offers an approach for managers and agencies to assess deer population condition and fawn survival. Urine collection methods, and the logistic problems involved in them, have been previously discussed by Kreeger et al. (1986) and Saltz and White (199la). Although further research is needed, urinary cortisol app~ar~ __ to be a reliable and easy technique to asses popUlation condition: �99 LITERATURE CITED Bartmann, R. M., G. C. White, and L. H. Carpenter. 1991. Compensatory mortality in a Colorado mule deer population. Wildl. Monogr. In press. Brown, R. D. 1984. The use of physical and physiological indices to predict the nutritional condition of deer - a review. Pages 52-63 in Proc. deer in the southwest: a workshop. New Mexico State Univ., Las Cruces. Connolly, G. E. 1981. Limiting factors and population regulation. Pages 245-286 in Wallmo, O. C., ed. Mule and black-tailed deer of North America. University of Nebraska Press, Lincoln. DelGiudice, G. D., ,L. D. Mech, and U. S. Seal. 1989. Physiological assessment of deer populations by analysis of urine in snow. J. Wildl. Manage. 53:284-291. Franzmann, A. W. 1985. Assessment of nutritional status. Pages 239-259 in R. J. Hudson and R. G. White, eds. Bioenergetics of wild herbivores. CRC Press, Inc. Boca Raton, FL. Grime, J. P. 1989. The stress debate: J. Linn. Soc. 37:3-17. symptom of impending synthesis? BioI. Hanks, J. 1978. Characterization of population condition. Pages 47-7~ in C. W. Fowler, and J.:D. Smith, eds. Dynamics of large mammal "popul.at Lons . Wiley, New York. Jaffe,-M. 1886. Veber den Reidersch1ag, we1chen Pikrinsaeure in normalen Harn erzeugt and veber eine neue Reuktion des Kreatinins. Z. Physiol. Chem. 10:391-400. Koehn, R. K., and B. L. Bayne. 1989. Towards a physiological and genetical understanding of the energetics of the stress response. Bio1. J. Linn. Soc. 37:i57 -171. Kreeger, T. J., G. D. DelGiudice, U. S. Seal, and P. D. Karns. 1986. Methods of urine collection for male white-tailed deer. J. Wild1. Dis. 22:442444. Miller, M. W., N. T. Hobbs, and M. C. Sousa. 1991. Detecting stress responses in Rocky Mountain bighorn Sheep (Ovis canadensis canadensis): reliability of cortisol concentrations in urine and feces. Can. J. Zoo1. 69:15-24. Nisbet, R. M., W. S. C. Gurney, W. W. Murdoch, and E. MCCauley. 1989. Structured population models: a tool for linking effects at individual and population level. BioI. J. Linn. Soc. 37:79-99. Olson, P. N., R. A. Bowen, P. W. Husted, and T. M. Nett. 1981. Effects of storage on concentration of hydrocortisone (cortisol) in canine serum and plasma. Am. J. Vet. Res. 42:1618-1620. Saltz, D.;"and G. C:-White. 1991a. Urinary cortisol and urea nitrogen responses to winter stress in mule deer. J. vrrai . Manage. 55-: 1-16. �100 ______ , and G. C. White. 1991b. Urinary cortisol and urea nitrogen responses in irreversibly undernourished mule deer fawns. J. Wi1d1. Dis. 27:41-46. SAS Institute, Inc. 1987. SAS/STAT guide for personal computers, version 6 ed. SAS Inst. Inc., Cary, NC. 1028pp. Stephens, D. B. 1980. Stress and its measurement in domestic animals: review of behavioral and physiological studies under field and laboratory situations. Adv. Vet. Sci. Compo Med. 24:179-210. Prepared by ~C0t;;b;;~te .. Colorado Sta~e University a �101 Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~ _ Project No. W-153-R-4 Mammals Research Work Plan No. 2A Mountain Sheep Investigations Job No. 4 Experiments to Identify and Manage Stress in Mountain Sheep Populations Period Covered: Authors: Personnel: July 1, 1990 - June 30, 1991 M. W. Miller, N. T. Hobbs, and M. A. Wild. K. W. Mills, K. P. Snipes, E. S. Williams, A. Boeger-Fields, and T. R. Spraker. Abstract We propose using an adaptive environmental assessment approach for studying and managing bacterial and viral diseases in free-ranging bighorn populations. Our .;tpproachwill involve simultaneous development'of_.a.computer model simulating bighorn population dynamic~ (including e~izootiology of . pasteurellosis) and of tools for identifying strains of Pasceurella haemolycica and quantifying immunological responses of bighorns to infection by these pathogens. We will use the model to identify variables sensitive to management perturbations in altering the dynamics of disease in bighorn populations; results will serve as the basis for designing management level experiments in the future. Diagnostic tools under development will be key components of laboratory and field experiments designed to evaluate potential tactics (including vaccination and/or treatment) for managing pasteurellosis in wild sheep, and appear prerequisite to initiating management level experiments. In conjunction with numerous cooperators, we summarized data gathered to date from a series of studies conducted in Colorado and elsewhere to develop a simulation model and serologic and bacteriologic tools for use in studying and managing pasteurellosis in free-ranging bighorn populations. We examined Pasceurella spp. isolates (n-5l) from wild bighorns (n-142) representing 5 indigenous herds during January-March 1991. Four of 5 herds sampled (Taylor River, Avalanche Creek, Tarryall Mountains, Chalk Creek) yielded Pasceurella spp. isolates. Prevalence estimates based on cultures of pharyngeal swabs ranged from 17-83% (mean 49%) among sampled herds. At least 6 distinct phenotypes (T3; 4; 3,4; 3,4,10; A7; and untypable) of Pasceurella spp. were identified among the 4 herds; we recovered T3 isolates from all 4 herds, but prevalence varied. Representative isolates from each herd have been submitted for genomic fingerprinting, and sera will be submitted for ELISA to exami.neexposure to a battery of P .. beemo l.ytz i.ce ..strains. �102 A pneumonia epizootic in the Taylor River-Almont Triangle bighorn herd killed at least 17 sheep across all age/sex classes; necropsies of 5 dead sheep (2 rams, 3 ewes) revealed subacute to chronic bronchopneumonia. Four distinct serotypes (T3; 4; 10; and 3,4,10) of nonhemo1ytic P. haemolytica were isolated from 4 sheep; Horaxella spp. and Actinomyces pyogenes were also isolated from some affected individuals. Immunoperoxidase staining of lung tissue revealed presence of bovine respiratory syncytial virus in 1 ewe; other viral or chlamydial agents were not detected. Gross, histologic, and fecal examinations revealed that lungworm did not appear to play a role in this epizootic. Preliminary evaluation of data from monthly collections of feces from captive bighorns suggested reproductive status may influence fecal cortisol excretion in bighorn ewes (Fig. 2); by May, fecal cortisol concentrations from pregnant ewes (mean±SE-39.S±6.9 ng/g dm) were about 77% higher than those from open ewes (22.2±3.0 ng/g dm)(P<O.OS). Based on these findings, further evaluation of seasonal and other influences on fecal cortisol measurements is warranted before these techniques are applied to studies of stress responses in freeranging bighorns. �103 EXPERIMENTS TO IDENTIFY AND MANAGE STRESS IN MOUNTAIN SHEEP POPULATIONS Michael W. Miller P. N. OBJECTIVE To treat bighorn sheep to control disease where necessary. SEGMENT OBJECTIVES 1. Develop a research strategy and proposal for managing bacterial and viral diseases in mountain sheep populations; begin conducting approved and funded research. 2. Design a population-level experiment to evaluate techniques for detecting stress in free-ranging bighorn sheep; begin conducting approved and funded research. MANAGEMENT OF BACTERIAL AND VIRAL DISEASES IN MOUNTAIN SHEEP POPULATIONS Inability to control infectious disease ou~breaks and subsequen~ mortality in mountain sheep populations. represents a significant obstacle to long-term success in their management. Although the "bighorn pn~umonia complex~_has been studied intensively for over 3 decades, little is known about many aspects of its etiology and epizootiology. Moreover, management interventions recommended for preventing or controlling this problem remain untested. Most previous efforts to improve understanding and management of the epizootiology of pneumonia in bighorns involved post hoc investigations .of dieoffs occurring in free-ranging sheep herds. These studies identified various etiological agents associated with known mortalities and attempted to determine predisposing causes and population consequences of individual outbreaks. From these investigations, comparisons of real or perceived patterns became the basis for hypotheses on the epizootiology of pneumonia in bighorns. Recognition of similar patterns in other outbreaks served as evidence supporting these as unifying hypotheses. Unfortunately, several of these hypotheses have failed to withstand rigorous experimental testing (Miller 1988, Miller et al. 1990, 1991). And, despite our best management efforts, bighorns continue to die. Our strategy for developing a better understanding of the epizootiology and management of bacterial and viral diseases in bighorn populations differs -generally, we propose to take an adaptive environmental assessment approach for studying the bighorn pneumonia complex. As a foundation for our research strategy, we have initially attempted to assimilate existing knowledge on bighorn population dynamics (including the epizootiology and consequences of infectious disease) into computer simulation models (Hobbs et al. 1990, Hobbs and Miller 1991). Because pasteurellosis appears to underlie virtually all r~s·piratory disease problems reported for bighorns: our modeling efforts have focused on the epizootiology of pasteurellosis in sheep populations .. We have constructed models that reflect dynamics of bighorn populations seen in nature �104 using the simplest assumptions necessary to reproduce those behaviors. Once we have a reliable working model, we plan to conduct simulation experiments to identify variables that might be particularly sensitive to management perturbations in altering the dynamics of disease in bighorn populations. Those results will serve as the basis for designing management level experiments in the future. In parallel with our modeling efforts,-we plan to conduct a series of experiments to develop, improve and standardize methods for collecting and interpreting diagnostic data to provide better estimates of key parameters driving our models. In particular, _we have been developing tools for identifying strains of Pasteurella haemolytica and quantifying immunological responses of bighorns to infection by these pathogens. These tools will be key components of laboratory and field experiments designed to evaluate potential tactics (including vaccination and/or treatment) for managing pasteurellosis in wild sheep, and appear prerequisite to initiating management level experiments. To this end, our recent efforts have focused on simulation modeling and on improving tools available for use in future management experiments that will be designed to study etiology, epizootiology, and prevention or control of disease outbreaks in bighorn populations: METHODS AND MATERIALS In conjunction with numerous cQoperators, we summarized data gathered to ~ate from a series of cooperative studies conducted in-Colorado and elsewhere to :devel-ppa simulation model (see details in WP2A,J8 Progress Report) and -- serol~gic and bacteriologic tools for use i~ studying and managing pasteurellosis in free-ranging bighorn popUlations; specific methods used in these projects have been described in detail elsewhere. Based on preliminary tindings generated from these efforts, we prepared a Program Narrative (Appendix A) and a Study Proposal (Appendix B) outlining additional experiments designed to provide data and to further develop diagnostic tools for eventual application in statewide bighorn management programs. Both plans were peer-reviewed and studies are in progress; one of these will be funded largely through Colorado Division of Wildlife Special Bighorn Sheep and Mountain Goat Auction and Raffle Funds available in FY91-92. Epizootiology of pasteurellosis in Colorado's indigenous Rocky Mountain bighorn sheep populations: We collected blood samples and nasal and pharyngeal swabs from indigenous bighorn herds trapped in January-March, 1991. Methods used to collect and handle field samples were as described in Appendix A, except that nasal swabs from 3 herds (Avalanche Creek, Tarrya11, Chalk Creek) were transported in modified Amies medium rather than Port-a-cul* tubes. _ Laboratory methods were as described in Appendix A. In a related activity, we also investigated an all-age pneumonia epizootic that occurred in the Taylor River-Almont Triangle bighorn herd. We performed postmortem examinations on 5 sheep carcasses and collected representative samples for diagnostic evaluation using established laboratory techniques. We also assisted in field operations to assess the extent and severity of this epizootic. ... .- Immunity to pasteurellosis in Rocky Mountain bighorn sheep: assessingspecificity of antibody responses to Pasteurelia haemolytica: We collected sera from free-ranging bighorns in conjunction with the preceding study. �105 Preparation of antigens from distinct phenotypic strains of P. haemolytica is currently underway, and serologic assays will be completed in FY9l-92 once funding becomes available. EXPERIMENTS ON MEASURING AND MANAGING STRESS IN BIGHORNS A proposal to evaluate stress responses of acclimated and wild free-ranging bighorn sheep to human disturbances in the Arkansas River corridor was developed as part of a comprehensive 3-year study to assess the impacts of recreational activities on bighorn population performance and habitat use in that area. Briefly, we plan to use both heart rate telemetry and fecal cortisol concentrations to compare stress responses between wild and bottleraised bighorns exposed to spontaneous and controlled human disturbances, and to evaluate management strategies for mitigating adverse responses (should they occur). The experimental approach proposed for use in this study is described in more detail in the 1990-91 Program Narrative for WP2A,J9. In planning that study, it became apparent that further development and understanding of fecal cortisol measurements were necessary in order to credibly apply these techniques to the Arkansas River study. In order to anticipate potential confounding influences on field applications of fecal cortisol measurements, we collected feces from captive bighorns at monthly intervals to examine seasonal influences on cortisol excretion. Samples were collected over a 3-5 day period at the-beginning of each month from individual captive bighorns of varied age/sex classes .. Feces were stored at -20 C until proce~sed for cortisol determination. Methods f~r processing feces and measuring cortisol were as described by MIller et al. (1991). RESULTS AND DISCUSSION The following abstracts summarize significant findings from a series of cooperative studies conducted in Colorado and elsewhere to develop tools for use in studying and managing pasteurellosis in free-ranging bighorn populations: REGULATION OF POPULATIONS BY INFECTIOUS DISEASE: SIMULATIONS OF PASTEURELLOSIS OUTBREAKS IN BIGHORN SHEEP (OVIS CANADENSIS). N. Thompso~ Hobbs and Michael W. Miller. Abstract: Many populations of bighorn sheep (Ovis canadensis) appear to be limited by their interactions with pathogens, notably Pasteurella spp., rather than by food supplies or predators. We developed a simulation model to represent interactions ~etween Pasteurella spp. and bighorn sheep populations. The model is an adaptation of the classical SIR system of coupled differential equations that has been widely applied to human diseases. Our model differs, however, in that its compartments (susceptible, infected, recovered) are represented as states within individual animals. Flows among compartments are translated into probabilities of transitions among states. We used this model to examine the idea that prevalent patterns in bighorn population dynamics can be explained by__intrinsic features of host-pathogen interactions. Averaged over several simulated populations, our individual-based model predicted an equilibrium virtually identical to that of the SIR model. However, because our model is inherently �106 stochastic, single populations showed a broad range of dynamical behavior including stasis, exponential growth, and episodic crashes in abundance. Thus, our model is faithful to 2 overriding patterns in bighorn population dynamics: regional suppression of animal numbers, and nonequilibrium behavior at local scales. We argue that both of these patterns can be explained by internal properties of host-pathogen interactions. External expla~ations, including habitat degradation and· fragmentation, environmental stress, parasitism, and contact with domestic animals are not necessary to explain epidemics and the ensuing population cycles frequently observed in bighorns. EPIZOOTIOLOGY OF PASTEURELLOSIS IN CAPTIVE ROCKY MOUNTAIN BIGHORN (OVIS CANADENSIS) LAMBS. Michael W. Miller, Margaret A. Wild, Kenneth W. Mills, Elizabeth S. Williams, and Amy Boerger-Fields. CANADENSIS Abstract: Poor lamb survival is often observed in Rocky Mountain bighorn sheep (Ovis canadensis canadensis) populations, particularly in the years following pneumonia epizootics. Causes for this reduced lamb recruitment are incompletely understood. Following an outbreak of pasteurellosis in a captive bighorn herd in 1984, 19 of 29 lambs born into that herd between 1985 and 1990 developed bronchopneumonia before 3 mo of age. We attributed all cases of pneumonia to nonhemolytic Pas~eurella haemoly~ica infections uncomplicated by protostrongylosis. Infection with P. haemoly~ica occurred shortly after birth. Three of 6 ewes sampled annually between 1988 and 1991 consistently -~hed Pa.~~eurella spp. in nasal ·secret;ionsat p~rttirition. Nonhemolytic P. haemoly~ica was not isola-ted from nasal or pharyngeal swabs of·n~wbo~ ~ambs (524 hrs old; n-22) , but was recovered from both sites in lambs ~ 5 days old. Lamb-to-lamb transmission also appeared to contribute to epizootic spread of Pas~eurella spp. Overall, 30 of 30 lambs sampled over a 4-yr period were infected by mid-summer. Biotype T. serotype 4, and untypable catalase positive isolates of nonhemolytic P. haemolytica were predominantly recovered from both sick and healthy lambs. An enzyme-linked immunosorbent assay measuring levels of antibodies to nonhemolytic P. haemoly~ica. biotype T, serotype 4, in colostrum from ewes and serum from lambs revealed the half-life of passive antibody levels in bighorn lambs was about 3 wks. Passive antibodies may have afforded lambs temporary protection from disease; pneumonia tended to occur in lambs >3 wks old. Our observations suggest that neonatal pasteurellosis may have profound effects on health and survival of b Lgho rn lambs. AN ENZYME-LINKED IMMUNOSORBENT ASSAY FOR DETECTING ANTIBODIES TO PASTEURELLA HAEHOLYTICA IN BIGHORN SHEEP (OVIS CANADENSIS). Ken Mills, Amy Boerger-Fields, Michael Miller, Margaret Wild, and Beth Williams. Abstract: Periodic pasteurellosis outbreaks cause extensive mortality in bighorn sheep (Ovis canadensis) populations, and may limit bighorn abundance throughout North America. It follows that tools for detecting presence of or exposure to Pas~eurella spp. infections could enhance the efficacy of management efforts for bighorns. We developed an enzymelinked immunosorberit assay (ELISA) to detect antibody to P. haemoly~ica in bighorn sheep. Antigen was initially prepared from a 20-hr culture of nonhemolytic P. haemoly~ica, biotype T, serotype 4, isolated from a �107 captive bighorn. Blocking assays using the original antigen strain, other P. haemolytica serotypes, and other bacterial species demonstrated high type-specificity for this ELISA. Based on these results, we developed a multivalent ELISA measuring antibody levels to distinct strains of P. haemolytica isolated from bighorn sheep or domestic livestock. Antibody levels measured with this multivalent ELISA appeared to differ between two captive bighorn herds differing in histories of exposure to P. haemolytica. Our results suggest measuring antibodies to P. haemolytica by ELISA may have applications in studying the epizootiology of pasteurellosis in bighorn populations, as well as i~ guiding relocation and other bighorn management activities. USING RIBOSOMAL RNA GENE RESTRICTION PATTERNS IN DISTINGUISHING STRAINS OF PASTEURELLA HAEMOLYTICA FROM BIGHORN SHEEP (OVIS CANADENSIS). K. P. Snipes, K. P., R. W. Kasten, M. A. Wild, M. W. Miller, D. A. Jessup, R. L. Silflow, and T. E. Carpenter. Abstract: Pasteurella haemolytica isolates (n - 31) from 2 captive herds of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) were characterized using established phenotyping and newer genomic fingerprinting methods. Phenotypes of isolates varied both within and between source herds. Nine different pheno cype.swere identified; biotype T and serotypes 4 and 3,4,10 predominated. Most isolates (23 of 31) were nonhemolytic, and all hemolytic isolates were from one herd. Three phenotypes (nonhemolytic T4; T3;4; and T3,4,10) were common to 'both herds. Evaluation of 14 restriction endonucleases revealed that· EcoRI, HincII, and PstI yielded optimal DNA fragmentation patterns for fibotyping P. haemolytica isolates using a 32P-labeled Escherichia coli rRNA probe. Ribotype pattern appeared to be a relatively stable trait: an identical ribotype was conserved within and across 19 passages of a stock P. haemolytica strain. Among the 31 bighorn isolates, ribotyping produced 6 subjectively distinct patterns; probing after digestion with EcoRI, HincII, or PstI consistently assigned isolates to respective ribotype groups. In contrast to phenotype~, ribotypes appeared unique to each herd. Comparing phenotypic and genotypic traits among isolates revealed associations of multiple serotypes with a single ribotype and mUltiple ribotypes with a single serotype, as well as presence and absence of hemolysis among otherwise identical isolates. These findings suggest ribotyping may be a useful adjunct to other bacteriology methods in.studying the epizootiology of pasteurellosis in bighorn sheep. EXPERIMENTAL AND FIELD EVALUATION OF PORT-A-CUL® TRANSPORT TUBES FOR RECOVERY OF PASTEURELLA HAEMOLYTICA FROM BIGHORN SHEEP (OVIS CANADENSIS) PHARYNGEAL SWABS. Margaret A. Wild, Michael W. Miller, Terry R. Spraker, and William J. Adrian. Abstract: Three pharyngeal swabs were collected from each of 25 healthy captive bighorn sheep (Ovis canadensis). We recovered nonhemolytic Pasteurella haemolytica from 23 of 25 (92%) swabs streaked onto blood agar plates and incubated immediately, from 16 of 25 (64%) swabs held in Port-A-Cu1® transport tubes for 24 hr, and from 1 of 25 (4%) swabs held in Port-A-Gul® tubes for 48 hr. Although the recovery rate from swabs held in Port-A-Cu1® tubes for 24 hr was only about 70% of that from direct swabs, rates were markedly higher than those for other transport �108 media. We subsequently used Port-A-Cul® tubes to transport pharyngeal swabs from healthy, free-ranging bighorns trapped throughout Colorado in winter 1990-91. Nonhemolytic P. haemolytica was isolated from 7 of 8 herds sampled; within those herds, isolation rates ranged from l7-87X of individuals sampled. Isolation rates for P. haemolytica exceeded rates in previous years when pharyngeal (1989-90) or nasal (1988-89) swabs were transported in modified Amies with charcoal, suggesting our previous sampling efforts may have underestimated prevalence of P. haemolytica infections in free-ranging herds. Using Port-a-cul® tubes and minimizing time between sample collection and processing (~24 hr) appears to be a practical way to optimize recovery of P. haemolytica from bighorn pharyngeal swabs. Complete manuscripts describing these studies and their results are in prep (Miller et al., Mills et al., Wild et al.) or are in review (Hobbs and Miller, Snipes et al.) for publication in peer-reviewed professional journals or proceedings. Epizootiology of pasteurellosis in Colorado'S indigenous Rocky Mountain bighorn sheep populations: One hundred forty-two wild bighorns from 5 indigenous herds were sampled in conjunction with capture operations during January-March, 1991. We examined Pasteurella spp. isolates (n-5l) from 4 of 5 bighorn herds sampled (Taylor River, Avalanche Creek, Tarryall Mountains, Chalk Creek); failure to recover Pasteurella spp. from 19 samples collected at Cottonwood Creek was likely due to delayed laboratory processing. Prevalence estimates based on cultures of pharyngeal swabs ranged from l7-83X· (mean 49X) among sampled herds (Fig. 1). Based on serotyping data from isolates we . examined,·there appeared to be differences in strains of P. haemolyti~a _ endemIc to these herds. In all, we encountered at least 6 distinct phenotypes (T3; 4; 3,4; 3,4,10; A7; and untypable). among the 4 herds. We recovered T3 isolates from all of these, but prevalence of this strain appeared to vary among herds (Fig. 1). Representative isolates from each herd have been submitted for genomic fingerprinting, and sera will be submitted for ELISA to examine exposure to a battery of P. haemolytica strains. We plan to use comparisons of genotypic and phenotYJ1ic traits of Pasteurella spp. among indigenous herds, along with serological evidence of exposure, to improve our understanding of the epizootiology and management of pasteurellosis in Colorado'S bighorn populations. The pneumonia epizootic in the Taylor River-Almont Triangle population occurred in the face of one of the more intensive bighorn herd management programs in Colorado; that program includes ongoing lungworm treatment and popUlation control programs, as well as extensive habitat improvement and protection efforts. Coughing rams were first observed in mid-March; further field observations revealed signs of respiratory disease in bighorns of all age/sex classes scattered throughout the winter range. To date, about 17 bighorns are known to have died; necropsies of 5 dead sheep (2 rams, 3 ewes) revealed subacute to chronic bronchopneumonia. Nonhemolytic P. haemolytica was isolated from 4 of these (the fifth was too decomposed to attempt bacteriology). At least 4 distinct serotypes (T3; 4; 10; and 3,4,10) were identified; 3 of these were from lungs of different individuals. Horaxella spp. and Actinomyces pyogenes were also isolated from some affected individuals. Immunoperoxidase staining of lung tissue revealed presence of bovine respiratory syncytial virus in 1 ewe; other viral or chlamydial agents have not been detected to date. Based on gross, histologic, and fecal examinations, lungworm did not appear to playa role in this epizootic. The duration of this outbreak prior to its detection remains unknown: although �109 prevalence of Pasteurella spp. was lowest among herds sampled this year, at least 1 yearling ram transplanted from the Taylor River-Almont Triangle herd to Glenwood Canyon in January died after developing pasteurellosis in late March; the fate of 39 other sheep removed from the Taylor River-Almont Triangle area remains unknown. We will continue working with Southwest Region Personnel to study this outbreak and its aftermath. EXPERIMENTS ON MEASURING AND MANAGING STRESS IN BIGHORNS Preliminary evaluation of data from monthly collections of feces from captive bighorns suggested "reproductive status may influence fecal cortisol excretion in bighorn ewes (Fig. 2); by May, fecal cortisol concentrations from pregnant ewes (mean±SE-39.S±6.9 ng/g dm) were about 77% higher than those from open ewes (22.2±3.0 ng/g dm)(P<O.OS). Based on these findings, further evaluation of seasonal and other influences on fecal cortisol measurements is warranted before these techniques are applied to studies of stress responses in freeranging bighorns. LITERATURE CITED Miller, M. W. 1988. Experiments toward detecting and managing stress in ROCky Mountain bighorn sheep (Ovis canadensis canadensis). Ph.D. Thesis, Colorado State University, Fort Collins. 106pp. Miller, M. W., "N. T. Hobbs, and M. C. -Sous a , 1991. Detecting stress responses in Rocky Mountain bighorn sheep (Ovis canadensis canadensis): reliability of cortisol conceritrations in urine and feces. Can.-J. Zoo1. 69:15-24. > Miller, M. W., N. T. Hobbs, and E. S. Williams. 1991. Spontaneous pasteurellosis in captive rocky mountain bighorn sheep (Ovis canadensis canadensis): clinical, laboratory, and epizootio10gica1 observations. J. Wi1d1. Dis. 27: in press. Wildlife Researcher ��111 Appendix A PROGRAM NARRATIVE State of Colorado Project No. W-1S3-R-4 Mammals Research 2A Mountain 4 Experiments to Identify and Manage Stress in Mountain Sheep Work Plan Job No. No. Sheep Investigations EPIZOOTIOLOGY OF PASTEURELLOSIS IN COLORADO'S INDIGENOUS ROCKY MOUNTAIN BIGHORN SHEEP POPULA~IONS A. NEED Successful bighorn sheep management appears depends on mitigating or eliminating pneumonia epizootics in otherwise thriving herds. Periodic pneumonia outbreaks cause extensive mortality in bighorn sheep populations throughout North America (Buechner 1960, Forrester 1971). Viral, bacterial, and parasitic agents have all been incriminated in these outbreaks. spp. are perhaps the most common pathogens associated with bronchopneumonia in bighorns. Two species (P. haemolytica and P. multocida), and several biotypes and serotypes within those species, have been isolated from bighorns during die-offs in the last decade (Feuerstein et ale 1980, Wishart et ale 1980, Foreyt and Jessup 1982, Onderka and Wishart 1984, Spraker et ale 1984, Schwantje 1986, Coggins 1988, Festa-Bianchet 1988, Onderka and Wil;Jhart1988., Onderka et al. 1988, Foreyt 1989)." A nonhemolytic variant of P. haemolytica biotype"T that may be .endemic in some bighorn herds (Onderka and Wishart 1988, Onderka et ale 1988) has been linked to a pandemic that affected bighorn populations across southwestern Canada in the early 1980's (Onderka and Wishart 1984, 1988). Experimental infections with other strains of P. haemolytica isolated from healthy domestic sheep have shown marked pathogenicity in bighorns (Onderka and Wishart 1988, Onderka et ale 1988, Foreyt 1989), supporting field reports linking bighorn and domestic sheep interactions with pneumonia in bighorns (Goodson 1982, Foreyt and Jessup 1982, Coggins 1988). Pasteurella Epizootiology of pasteurellosis in bighQrn populations is poorly understood. A sound unifying hypothesis explaining the ecological basis of pneumonia in bighorn sheep has not emerged (Miller 1988, Miller et ale 1991). The relative importance of endemic and introduced disease agents as factors limiting bighorn abundance remains unclear (Miller et ale 1991, Wild and Miller 1991). In the absence of knowledge about the epizootiology of pasteurellosis, effective strategies for managing pneumonia in bighorn populations have not emerged. Wildlife managers can neither predict nor prevent outbreaks in bighorns. consequently, long-term attempts to manage bighorns often fail. In order to effectively manage pneumonia in bighorn sheep, we must begin to unravel and understand complicated ecological relationships involving disease agents, wild and domestic hosts, and environmental factors affecting both. To begin doing this, we need to compare distribution, prevalence, and transmission of specific pathogens among and within bighorn populations, compare individual and population responses to specific pathogens, and assess exposure history and status of bighorn herds with respect to various disease agents. Because pasteurellosis prevails as an important component of pneumonia outbreaks in bighorn sheep," we propose to sample indigenous bighorn herds to meaeuze and compare distribution, prevalence, and immunity to Pasteurella spp. infections. �112 B. OBJE~IVES Specific objectives of this study are to: (1) compare rates for tonsillar carriage and nasal shedding of Pasteurella spp. among 10 indigenous bighorn herds, as well as among ewe, ram, and lamb subpopulations within those herds, (2) compare isolated strains of P. haemolytica among and within sampled herds using phenotypic and genotypic characterizations of isolates, (3) compare serum antibody titers to Pasteurella within sampled herds, and (4) examine correlations between infection rates, P. haemolytica strains, herd immunity, and population performance (historic and current) in sampled bighorn populations. C. spp. among and EXPECTED RESULTS AND BENEFITS Managing the bighorn pneumonia complex is essential to improving success of management programs for Rocky Mountain bighorn sheep. By understanding how Pasteurella spp. persist in, spread through, and are distributed among bighorn populations, specific management practices can be directed toward preventing pneumonia outbreaks. Knowledge of distribution and prevalence of various Pasteurella spp. strains will aid in detecting and/or preventing introduction of novel strains to susceptible bighorn populations. Determining relationships between antibody levels and susceptibility or resistance to pasteurellosis will be useful in developing approaches for predicting pneumonia outbreaks ~hrough herd moni~oring. Incorporating these estimates for pa~ameters describing bighorn pasteurellosis-into simulation models (eg. Hobbs et al. 1990) will allow managers to explore potential consequences of management actions with respect to disease outbreaks, and to examine -alternatives for controlling pneumonia outbreaks. Moreover, analyzing strain and immunity data could lead to development of vaccines preventing pasteurellosis in bighorns. Ultimately, we believe developing approaches for estimating these parameters will provide a foundation for herd health monitoring and management as part of comprehensive management programs for bighorn sheep in Colorado and elsewhere. D. APPROACH 1. Hypotheses Rates for tonsillar carriage and nasal shedding of Pasteurella spp. will not differ among or within indigenous bighorn herds sampled. Phenotypic and genotypic traits of P. haemolytica will not differ among-or within herds. Serum antibody titers to Pasteurella among or within herds. isolates spp. will not differ 2. Methods a. Study herds - We will sample 10 indigenous herds of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) over a 2-year period. Five of these (Alamosa Canyon, Chalk Creek, Ouray, Taylor River, and Waterton Canyon) have experienced documented pneumonia outbreaks within the last 10 years; 5 others (Avalanche Creek, Cottonwood Creek, Sangre De Cristo Mountains, Tarryall MQ~ntains, and Trickle _ Mountain) have -been free -of epizootic- pneumonia for at lea-at 20 years. Estimates of population performance and composition for each herd will be obtained from existing inventory data generated by regional management programs. �113 E. F. b. Sample collection - Based on current population estimates, we will calculate target sample sizes for each herd necessary to provide prevalence estimates within ± 10% of true prevalence at 95% confidence level (DiGiacomo and Koepsell 1986). Samples for bacteriology and serology will be collected from each herd in conjunction with live capture operations and/or hunter surveys. Nasal and tonsillar swabs from individually identified bighorns will be plated directly onto bighorn sheep blood agar and MacConkey's agar and incubated immediately (Wild and Miller 1991, and unpubl. data). We will also collect 12 ml of blood from each sheep sampled; serum will be separated and stored at -20 C. c. Characterization of P. haemolytica isolates - Pasteurella spp. colonies will be isolated and identified from primary culture plates using established methods (Carter 1984). All Pasteurella spp. isolates will be lyophilized. Those biochemically identified as P. haemolytica (regardless of hemolysis reactions) will be serotyped using both rapid plate agglutination (Frank and Wessman 1978) and indirect hemagglutination (Biberstein et ale 1960). We will further characterize P. haemolytica isolates using genomic fingerprinting (Snipes et ale in review). d. Serology - Serum antibodies to Pasteurella spp. will be measured using an enzyme-linked immunosorbent assay (Gillette et ale 1989, Mills et ale in prep). We will use western blot analysis to examine strain specificity of bighorn antibodies to Pasteurella spp. among and within sampled herds. ANALYSIS We will calculate prevalence rates for tonsillar carriage and nasal shedding of Pasteurella spp. and compare these among herds and among ewe, ram, and lamb subpopulations within herds using'categorical m9deling. We .will use Cochran's Q test to compare distributions of phenotypically and/or genotypically distinct strains of P. haemolytica among and-within herds. Serum antibody levels to Pasteurella spp. will be compared by analysis of variance with herd, subpopulation, and health histories as main effects. SCHEDULE February 1991 - April 1993 May 1991 - July 1993 Collect samples from indigenous herds, culture and identify Pasteurella spp. isolates. Perform genomic fingerprinting on P. isolates, measure serum antiboby levels and examine strain specificities. haemolytica August - December January 1993 - May 1994 G. PERSONNEL Michael W. Miller' Margaret A. Wild' Kurt P. snipes2 Colorado Prospect 2 Analyze data. Prepare manuscripts for publication in peer-reviewed journals and offer management recommendations based on data generated. Principal Investigator co-principal Investigator Co-Principal Investigator Division of Wildlife, Wildlife Research Road, Fort Collins, ·Colorado 80526. ' center,- 317 West Department of Epidemiology and Preventive Medicine, School of Veterinary Medicine, University of California, Davis, California 95616. �114 Kenneth W. Mills3 H. Co-Principal BUDGE~ Personal Services Operating Supplies and Services Bacteriology Serotyping DNA Typing Serology Total Operating Travel Expenses Capital Expenditures TOTAL I. Investigator LI~RATtJRE $ 40,000 $ $ $ S $ 5,000 2,500 5,000 2,500 15,000 3,000 2,000 60,000 CI~D Biberstein, E. L., M. G. Gills, and H. D. Knight. 1960. Serologic types of haemolytica. Cornell Vet. 50:283-300. Buechner, H. K. 1960. The bighorn sheep in the United States, its past, present, and future. Wildl. Mono. 4:74. Carter, G. R. 1984. Diagnostic procedures in veterinary bacteriology and mycology. C. C. Thomas, Springfield, Ill., 515 pp. Coggins, V. L. 1988. The Lostine Rocky Mountain bighorn sheep die-off and domestic sheep. Bienn. Symp. Northern Wild Sheep and Goat Counc. 6:57-64. DiGiacomo, R. F., and T. D. Koepsell. 1986. Sampling for detection of infection or disease in animal populations. J. Am. Vet. Med. Assoc. 189: Pasteurella 22-23. Festa-Bianchet, M. 1988. A pneumonia epizootic in bighorn sheep, with comments on preventive management. Bienn. Symp. Northern Wild Sheep and Goat Counc. 6:66-76. . Feuerstein. V., R. L. Schmidt, C. P. Hibler, and W. H. Rutherford. 1980. BighQrn sheep mortality in the Taylor River-Almont Triangle area, 1978-1979: a case study. Colo. Div. of Wild., Spec. Rep. No. 48. l~-pp. Foreyt, W. J. 1989. Fatal Pasteurella haemolytica pneumonia in bighorn sheep after direct contact with clinically normal domestic sheep. Am. J. Vet. Res. 50:341-343. Foreyt, W. J., and D. A. Jessup. 1982. Fatal pneumonia of bighorn sheep following association with domestic sheep. J. Wildl. Dis. 18:163-169. Forrester, D. J. 1971. Bighorn sheep lungworm-pneumonia complex. pp. 158-173 in J. W. Davis; and R. C. Anderson, eds. Parasitic Diseases of Wildlife. Iowa State Univ. Press, Ames. Frank, G. -H., and G. E. Wessman. 1978. Rapid plate agglutination procedure for serotyping Pasteurella haemolytica. J. Clin. Microbiol. 7: 142-145. Gillette, K. G., G. H. Frank, and J. M. Sacks. 1989. Development and evaluation of an enzyme-linked immunosorbent assay for bovine antibody (IgG) to Pasteurella haemolytica. Am. J. Vet. Res. 50:106-110. Goodson, N. J. 1982. Effects of domestic sheep grazing on bighorn sheep populations: a review. Proc. Biennial Symp. Northern Wild sheep and Goat Counc. 3:287-313. Hobbs, N. T., M. W. Miller, J. A. Bailey, D. A. Reed, and R. B. Gill.. 1990. Biological criteria for introductions of large mammals: using simulation models to predict impacts of competition. Trans. N. Am. Wildl. Nat. Res. Conf. 55: 620-632. Miller, M. W. 1988. Experiments toward detecting and managing stress in Rocky Mountain bighorn sheep (Ovis canadensis canadensis). Ph.D. Thesis, Colorado State Univ, Ft. Collins. l06pp. Miller, M. W., No T. Hobbs, and E. So Williams. 1991. Spontaneous pasteurellosis in captive Rocky Mountain bighorn sheep (Ovis canadensis canadensis): clinical, laboratory, and epidemiological observations. J. Wildl. Dis. 27: in press. - 3 Wyoming state Veterinary Laboratory, Street, Laramie, Wyoming 820700 University of Wyoming, 1190 Jackson �115 Mills, K. M., M. W. Miller, E. S. Williams, and M. A. Wild. 1991. Development and evaluation of an enzyme-linked immunosorbent assay for measuring antibody" titers to Pasteurella haemolytica in Rocky Mountain bighorn sheep (Ovis canadensis canadensis). in prep. Onderka, D. K., and W. D. Wishart. 1984. A major bighorn sheep dieoff from pneumonia in southern Alberta. Bienn. Symp. Northern Wild Sheep and Goat Counc. 4: 356-363. Onderka, D. K., and W. D. Wishart. 1988. Experimental" contact transmission of Pasteurella haemolytica from clinically normal domestic sheep causing . pneumonia in Rocky Mountain bighorn sheep. J. Wildl. Dis. 24: 663-667. Onderka, D. K., S. A. Rawluk, and W. D. Wishart. 1988. Susceptibility of Rocky Mountain bighorn sheep and domestic sheep to pneumonia induced by bighorn and domestic livestock strains of Pasteurella haemolytica. Can. J. Vet. Res. 52: 439-444. " schwantje, H. M. 1986. A comparative study of bighorn sheep herds in southeastern British Columbia. Bienn. Symp. Northern Wild Sheep and Goat Counc. 5: 231-252. Snipes, K. P., R. W. Kasten, M. A. Wild, M. W. Miller, D. A. Jessup, R. L. Silflow, and T. E. Carpenter. " Using ribosomal RNA gene restriction patterns in distinguishing strains of Pasteurella haemolytica from bighorn sheep (Ovis canadensis). J. Wildl. Dis., in review. Spraker, T. R., C. P. Hibler, G. G. Schoonveld, and W. S. Adney. 1984. Pathologic changes and microorganisms found in bighorn sheep during a stress-related die-off. J. Wildl. Dis. 20:319-327. Wild, M. A., and M. W. Miller. 1991. Detecting nonhemolytic Pasteurella haemolytica infections in healthy Rocky Mountain bighorn sheep (Ovis canadensis canadensis): influences of sample site and handling. J. Wildl. Dis. 27: in press. " Wishart, W. D., J. Jorgenson, and M. Hinton. 1980. A minor die-off of bighorns from pneumonia in southern Alberta. Bienn. Symp. Northern Wild Sheep and Goat Counc. 2: 229-247. ��117 Appendix B STUDY PROPOSAL IMMUNITY TO PASTEURELLOSIS IN ROCKY MOUNTAIN BIGHORN SHEEP: ASSESSING SPECIFICITY OF ANTIBODY RESPONSES TO PASTEURELLA HAEHOLYTICA Michael W. Miller1, Kenneth W. Mills2, Amy Boerger-Fields2, Margaret A. Wild1, and Elizabeth S. Williams2, Principal Investigators 1 Colorado Division of Wildlife, Wildlife Research Center, 317 West Prospect, Fort Collins, Colorado 80526. 2 Wyoming State Veterinary Laboratory, University of Wyoming, 1174 Snowy Range Road, Laramie, Wyoming 82070. _ A. NEED Long-term success of bighorn management depends on our ability to manage or eliminate pneumonia epizootics in otherwise thriving herds. Periodic pneumonia outbreaks cause extensive mortality in bighorn- sheep populations, and limit bighorn abundance throughout North America (Buechner 1960, Forrester 1971). Various viral, bacterial, and parasitic agents have been incriminated in these out1::lreaks historically (Spraker and,Hibler 1982), but Past:eurella spp_ are perh~ps the most common pathogens associated with bronchopneumonia in bighorns. Two species (P. haemolyt:ica and P. mult:ocida) and several '~strains" (biotjpes and serotypes) of Past:eurella spp. have been isolated from bighorns during dieoffs in the last decade (Feuerstein et al. 1980, Wishart et al. 1980, Foreyt.and Jessup 1982, Onderka and Wishart 1984, Spraker et al. 1984, Schwantje 1986, Coggins 1988, Festa-Bianchet 1988, Onderka and Wishart 1988, Onderka et al. 1988, Foreyt 1989). Among these, a non-hemolytic vari~nt of P. haemolyt:ica biotype T may be endemic in bighorn herds in Colorado and elsewhere (Onderka and Wishart 1988, Onderka et al. 1988, Miller et al. 1991, M. W. Miller, unpubl. data); this agent appears responsible for the pandemic that affected bighorn populations from southern British Columbia an~ Alberta to Montana and Idaho 5-6 years ago (Onderka and Wishart 1984, 1988). Other strains of P. haemolyt:ica isolated from healthy domestic sheep have shown marked pathogenicity in experiments using captive bighorns (Onderka and Wishart 1988, Onderka et al. 1988, Foreyt 1989), supporting field reports linking bighorn and domestic sheep interactions with pneumonia in bighorns (Goodson 1982, Foreyt and Jessup 1982, Coggins 1988). Despite compelling data from experiments and retrospective field studies, the relative importance of endemic and introduced disease agents as factors limiting bighorn abundance remains unclear. Because many epidemiological .aspects of the bighorn pneumonia complex are poorly understood, wildlife managers can neither predict nor prevent pneumonia in bighorns. Consequently, long-term attempts to manage bighorns often fail. In order to effectively manage pneumonia in bighorn sheep, we must begin to unravel and understand complicated ecological relationships involving disease agents, wild and dC?_mestichos~s, and environmental factors affecting both. To do this, we need tools for measuring individual and population responses to specific pathogens, �118 as well as for assessing exposure history and status of bighorn herds with respect to various disease agents. Serological tests provide this type of information by detecting or measuring antibodies induced by host/pathogen interactions. Antibody levels indicate exposure to specific pathogens, and may also be correlated with disease . resistance in some cases (reviewed by Confer 1988 for bovine pasteurellosis). Data of this nature could be invaluable in efforts to clarify many aspects of the bighorn pneumonia complex. Over the past two years we have developed an enzyme-linked immunosorbent assay (ELISA) that measures antibodies to Pasteurella spp. in bighorn sheep (Mills et al., 1991). Preliminary data generated using this ELISA have already provided insights into the epizootiology of pasteurellosis in bighorn lambs (Mills et al. 1991, M. W. Miller, unpubl. data). We propose to use-sodium dodecyl sulfatepolyacrylamide gel electrophoroesis (SDS-PAGE) and western blot analyses to further develop our assay. This approach will allow ELSIA_measurement of antibody levels to specific strains of P. haemolytica isolated from freeranging bighorn herds throughout Colorado. Data from these analyses will be used in comparing performance of bighorn herds exposed to different strains of P. haemolytica. Such data will also be used in evaluating health of potential donor herds as a means of minimizing introduction of novel pathogens to recipient herds through the statewide bighorn transplanting program. B. OBJECTIVES Spec Lf Lc objectives of this study ,are to: (i) use SDS-PAGE and western blot ana~yses to separate and identify strain-specific antigenic proteins from 5 strains of P. haemolytica isolated from Rocky Mountain bighorn sheep, (2) modify the Pasteurella spp. ELISA using a battery of strainspecific antigens, and (3) compare levels of antibody to Pasteurella spp. in sera from 5 geographically distinct bighorn herds using the modified ELISA. C. EXPECTED RESULTS AND BENEFITS Managing the bighorn pneumonia complex is essential to improving success of management programs for Rocky Mountain bighorn sheep. By understanding how respiratory pathogens persist in and spread through bighorn populations, management practices can be directed toward preventing pneumonia outbreaks -developing assays that measure antibodies to specific disease agents in bighorns appears pivotal in gaining this knowledge. Techniques for measuring bighorn antibodies to specific strains of Pasteurella spp. will allow biologists and researchers to document, study, and perhaps differentiate between pneumonia epizootics in bighorns caused by endemic and introduced strains. Data from studies of relationships between antibody levels and susceptibility or resistance to pasteurellosis will be useful in developing approaches for predicting pneumonia outbreaks through herd monitoring and/or simulation modeling; moreover, these data could lead to development of vaccines preventing pasteurellosis in bighorns. Ultimately, we believe these and other similar tools will provide a foundation for herd health monitoring �119 and management as part of comprehensive management programs for bighorn sheep in Colorado and elsewhere. D. APPROACH 1. Hypothesis Ho: 2. Antibody levels to strain-specific P. haemolytica antigens will not differ among or within geographically-distinct sheep herds. Methods Techniques described elsewhere (Ellis et al., 1991) will be used in SDSPAGE and western blot analyses to separate and identify strain-specific antigenic proteins from P. haemolytica isolates recovered from Rocky Mountain bighorn sheep. Generally, we will use SDS-PAGE to separate bacterial proteins from 5 phenotypically-distinct strains of P. haemolytica isolated from free-ranging Rocky Mountain bighorn sheep. Separated proteins will be transferred directly to nitrocellulose filters. We will then react bighorn sheep sera to these proteins to determine antigen specificity and activity of antibodies to the various P. haemolytica strains. Once unique strain-specific antigens have been identified and produced, we will incorporate them into the existing Pasteurella spp. ELISA (Mills et al., 1991). We will then measure antibody leve-ls to these 5 P". haemolytica strains 'Ln sera from 5 _ geographically:distinct bighorn-herds using ELISA techniques described-by Mills et al. (1991). All antibody levels will be reported as optical density (OD) readings. E. ANALYSIS Antibody levels measured in bighorn sera will be compared using two-way analysis of variance, with P. haemolytica strain and herd as main effects. All analyses will be performed using the SAS program for general linear models (SAS 1987). F. SCHEDULE January-March 1991 July-August 1991 Collect sera and P. haemolytica isolates from freeranging bighorns in conjunction with ongoing studies. Perform SDS-PAGE and western blot analyses on P. isolates, identify and produce unique antigens. haemolytica September-October 1991 Modify, test, and revalidate ELISA. November-December January-March 1992 1991 Measure antibody levels to sera from free-ranging bighorn herds using modified ELISA. Analyze and summarize data, prepare manuscripts for publication in peer-reviewed journals. �120 G. BUDGET Personal Services Laboratory Technician, 1 mo Operating Expenses SDS-PAGE and western blot analyses Antigen purification and production ELISA determinations TOTAL· * $ 1000 2000 1000 1000 $ 5000 (Amount requested from Special Bighorn Sheep and Mountain Goat Auction and Raffle Funds. In addition, CDOW will provide support for collecting and preparing serum and bacterial samples, and will pay publication charges; WSVL will provide miscellaneous supplies and capital equipment needed to run assays, and will waive administrative charges. Investigators' salaries will be paid by their respective agencies.) H. LITERATURE CITED Buechner, H. K. 1960. The bighorn sheep in the United States, its past, present, and future. Wi1dl. Mono. 4:74. Coggins, V. L. 1988. The Lostine Rocky Mountain bighorn she~p die-off and domestic sheep. Bienn. Symp. Northern Wild Sheep and Goat Counc. 6:57-64. Confer ,.A. W. 1988.· Bovine pneumonic pasteurellosis': Immunity to . Pasteurella liaemolyiica. J. Am. Vet. Med. Assoc. 193: 1.308~13l6. Ellis, J. A., D. A. Hawk, K. W. Mills, and D. L. Pratt. 1991". Ant Lgen specificity and activity of ovine antibodies induced by immunization with Corynebacterium pseudotuberculosis culture filtrate. Vet. Immuno1. Immunopath. in press. Festa-Bianchet, M. 1988. A pneumonia epizootic in bighorn sheep, with comments on preventive management. Bienn. Symp. Northern Wild Sheep and Goat Counc. 6:66-76. Feuerstein, V., R. L. Schmidt, C. P. Hibler, and W. H. Rutherford. 1980. Bighorn sheep mortality in the Taylor River-Almont Triangle area, 1978-1979: a case study. Colo. Div. of Wild.·, Spec. Rep. No. 48. 19 pp. Foreyt, W. J. 1989. Fatal Pasteurella haemolytica pneumonia in bighorn sheep after direct contact with clinically normal domestic sheep. Am. J. Vet. Res. 50:341-343. Foreyt, W. J., and D. A. Jessup. 1982. Fatal pneumonia of bighorn sheep following association with domestic sheep. J. Wi1dl. Dis. 18:163-169. Forrester, D. J. 1971. Bighorn sheep lungworm-pneumonia complex. pp. 158-173 in J. W. Davis, and R. C. Anderson, eds. Parasitic Diseases of Wildlife. Iowa State Univ. Press, Ames. Goodson, N. J. 1982. Effects of domestic sheep grazing on bighorn sheep populations: a review. Proc. Biennial Symp. Northern Wild sheep and Goat Counc. 3:287-313. Mills, K. M., M. W. Miller, E. S. Williams, and M. A. Wild. 1991. Development and evaluation of an enzyme-linked immunosorbent assay for measuring levels of antibody to Pasteurella haemolytica in Rocky Mountain bighorn sheep (Ovis canadensis canadensis). in prep. Onderka, D. K., and W. D. Wishart. 1984. A major bighorn sheep dieoff from pneumonia in southern Alberta. Bf erm Symp. Northern Wild Sheep and Goat Counc. 4: 356-363. �121 Onderka, D. K., and W. D. Wishart. 1988. Experimental contact transmission of Pasteurella haemolytica from clinically normal domestic sheep causing pneumonia in Rocky Mountain bighorn sheep. J. Wildl. Dis. 24: 663-667. Onderka, D. K., S. A. Rawluk, and W. D. Wishart. 1988. Susceptibility of Rocky Mountain bighorn sheep and domestic sheep to pneumonia induced by bighorn and domestic livestock strains of Pasteurella haemolytica. Can. J. Vet. Res. 52: 439-444. SAS. 1987. SAS/STAT Guide for personal computers, version 6 edition. SAS Institute, Cary, North Carolina. 1028pp. Schwantje, H. M. 1986. A comparative study of bighorn sheep herds in southeastern British Columbia. Bienn. Symp. Northern Wild Sheep and Goat Counc. 5: 231-252. Spraker, T. R., and C. P. Hibler. 1982. An overview of the clinical signs, gross and histological lesions of the pneumonia complex of bighorn sheep. Bienn. Symp. Northern Wild Sheep and Goat Counc. 3:163-172. Spraker, T. R., C. P. Hibler, G. G. Schoonveld, and W. S. Adney. 1984. Pathologic changes and microorganisms found during a stress-related die-off. J. Wildl. Dis. 20:119-327. Wishart, W. D., J. Jorgenson, and M. Hinton. 1980. A minor die-off of bighorns from pneumonia in southern Alberta. Bienn. Symp. Northern Wild Sheep and Goat Counc. 2: 229-247. �122 .---. ~ 0 - 100 _ ..._... 80 W T3 DT4 f2SCI 0 Z 60 ...I 40 > W 20 OTHER T oOTHER W <C x"49 H A I:C Q. 0 AC TR TA CC HERD .-..E "0 -- 50 C') C') c ....,_, ..J 0 40 30 en -III: -.- PREGNANT -.- OPEN I RUT I /i 'I T 20 ~~_-_,t' __ 0 o ...I <C 10 W 0 c LL ---.•.. - --- rOCT NOV DEC JAN /,1 T -' FEB MAR MONTH T I ,,'''1 I l.AMBING I APR MAY �123 Colorado.Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~ _ Project No. W-153-R-4 Mammals Research Work Plan No. 2A Mountain Sheep Investigations Job No. 7 Experimental Evaluation of Mountain Sheep Transplanting and Disease Treatment Period Covered: Authors: Personnel: July I, 1990 - June 30, 1991 M. W. Miller, C. Anderson, Jr., and J. Vayhinger D. A. Reed, S. Ogilvie, C. Anderson, Sr. Abstract To foster the concept of approaching statewide transplanting and disease treatment programs for mountain sheep populations as management experiments, we prepared a research·prospectus outlining a management experiment to·evaluate ·and compare management strategies for reducing lungworm burdens a~d improving lamb ~urvival in selected mountain sheep herds. We proposed to evaluate alternative lungworm treatment regimes in a 4-year management experiment with l~tin square design, using mountain sheep populations in the Tarryall Mountains and Collegiate Peaks to evaluate the following treatment·regimes: a) baiting with alfalfa hay and apple pulp treated with fenbendazole (bait/treat); b) baiting with alfalfa hay and apple pulp without fenbendazole (bait/no treat); c) placing fenbendazole-treated salt blocks on bait stations (no bait/treat); ·and d) withholding bait and fenbendazole (no bait/no treat). Treatments will be rotated among herds ,such that at the end of 4 years each site will have received all 4 treatments. We pLan to compare lainbsurvival among ewe/treatment groups as a measure of treatment efficacy using individual radioco1lared ewes (n-20/site) for our'observations. . During February-March, 1991, 50 adult ewes were captured and radiocollared at 4 sites, 2 in the Tarryall (Cotton Gordon's, Sugarloaf Mountain) and 2 in the Collegiate Mountains (Chalk Creek, Cottonwood Creek); both dropnets and chemical immobilization were used in captures. At least 2 ewes died as a direct result of capture, and 2 others have died since capture. Preliminary pretreatment observations revealed that 31 of 46 surviving ewes (67%) were observed either lactating (n-ll) or nursing lambs (n-20) during May and/or June 1991; 6 ewes showed no evidence of lambing, and the status of 9 others remained undetermined as of late June. Only 1 known lamb loss, presumed a mortality, has been detected to date. Movements have varied widely both among and within monitored herds. ��125 EXPERIMENTAL EVALUATION OF MOUNTAIN SHEEP TRANSPLANTING AND DISEASE TREATMENT Michael W. Miller P. N. OBJECTIVES Design, conduct, and report on management experiments to evaluate efficacy of transplanting and disease treatment practices for managing mountain sheep populations. AGREEMENT OBJECTIVES Prepare a prospectus for management level experiments evaluating Colorado's mountain sheep transplanting and parasite control programs. Colorado's mountain sheep management program is recognized as among the most aggressive in North America. A combination of management practices, including transplanting to establish new herds and anthelmintic treatment to improve herd health, appears to have produced a threefold increase in bighorn numbers statewide over the last 20 years. However, the contributions of individual management strategies to the overall success of this program cannot be discerned (Bailey 1990). Transplanting bighorns to unoccupied ranges and treating resident herds to control lungworms are 2 of the most intensive (and costly) practices used to manage sheep in Colorado, yet neither of these vrograms has ever been evaluated experimentally to assess long-term efficacy. Recent" analyses of available herd data suggested that only about half of all transplant efforts succeed in establishing viable bighorn herds, and that parasite treatment does not necessarily prevent disease outbreaks or improve performance of treated bighorn herds (Bailey 1990). Unfortunately, management practices for most of Colorado's bighorn populations are so confounded that even interpretation of the aforementioned evaluation is equivocal. Clearly, management-level experiments are needed to evaluate and compare efficacy and efficiency o~ bighorn management practices in Colorado. The Colorado Division of Wildlife's Terrestrial Wildlife Research Section is committed to conducting management experiments to evaluate- efficacy of transplanting and disease treatment practices for managing mountain sheep populations. In conjunction with the Division's Southeast Regional staff, we have proposed the following management experiment to evaluate and compare management strategies for reducing lungworm burdens and improving lamb survival in selected mountain sheep herds: RESEARCH PROSPECTUS Improving Mountain Sheep Population Performance With Anthelmintic Treatment: An Experimental Evaluation of Management Alternatives Michael W. Miller, Jack Vayhinger, and Stan Ogilvie PRDBIEH Mountain sheep (Ovis canadensis canadensis) popula-tions throughout North America are plagued by pneumonia outbreaks caused by a complex of bacterial, �126 parasitic, and/or viral agents (reviewed by Spraker and Hibler 1982). These epizootics and subsequent population declines represent a significant obstacle to long-term success in mountain sheep management (Buechner 1960, Forrester 1971). Treating with anthe1mintics to reduce parasitic lungworm (Protostrongylus spp.) burdens has become an integral part an aggressive management program to reduce disease outbreaks and enhance productivity of mountain sheep herds in Colorado (Schmidt et al. 1979). Although some combination of treating, trapping and other management activities has increased sheep numbers statewide over the last 2 decades, it is unclear which strategies were most influential in this achievement (Bailey 1990). In light of the growing number of significant mountain sheep herds throughout Colorado, the apparent intensity of management required to perpetuate individual populations, and the costs associated with applying intensive management, it is becoming increasingly important to explore alternatives for efficient but efficacious management practices. Here, we propose a management experiment to examine effects of alternative lungworm treatment strategies on mountain sheep lamb survival and population performance. APPROACH We plan to evaluate alternative lungworm treatment regimes in a 4-year management experiment with latin square design. We will use mountain sheep populations in the Tarryall Mountains and Collegiate Peaks to evaluate treatment regimes. Four existing bait stations are already established within occupied ranges of the 3 distinct populations (Tarryall, Cottonwood Creek, Chalk Cliffs) that will be included in our study; 2 sites with distinct group fidelity (Sugarloaf Mountain, Twin Eagles) are established for the Tarryal1 herd.· Sites will be paired by location (Tarryall ~r ColIegiate) and average annual site attendance. At each site, we will initially capture, radiocollar, and release 15-20 adult ewes that will be used to measure treatment effects. Beginning in the following winter, we will impose one of the following management treatments at each site: a) baiting with alfalfa hay and apple pulp treated with fenbendazole (bait/treat); b) baiting with alfalfa hay and apple pulp without fenbendazole (bait/no treat); c) placing fenbendazole-treated salt blocks on bait stations (no bait/treat); and d) withholding bait and fenbendazole (no bait/no treat). In each succeeding winter, these treatments will be rotated such that at the end of 4 years each site will have received all 4 treatments. We will compare lamb survival among ewe/treatment groups as a measure of treatment efficacy. Radio-collared ewes with known treatment histories will be relocated every 2 weeks from 1 May to 30 September. We will observe ewes for presence or absence of a nursing lamb, and will also note condition, behavior, and apparent health of all lambs that are observed. We will also collect fecal pellet groups from lambs nursing marked ewes at monthly intervals. In addition to data on lamb survival and fecal lungworm levels, we will record group sizes, composition, and locations for all sheep observed. Differences in lamb survival and fecal lungworm levels within and among- ewe/treatment groups will be examined using rep~ate(Cmeasures analysis of variance. �127 SCHEDULE Activity Capture and radiocollar ewes 1991 Impose treatments and monitor responses 1992-96 Analyze data, publish results, and recommend management alternatives 1996-97 MATERIALS AND METHODS We began capturing bighorn ewes in preparation for our management-level experiment evaluating Colorado's mountain sheep parasite control program. During February and March, 1991, we used dropnets and/or chemical immobilization (about 2.6 mg carfentanil HCl and about 15 mg xylazine HCl/animal) to capture adult and yearling ewes at 4 sites in the Tarryall and Collegiate Mountains. Captured ewes were fitted with radiocollars (148.0-149.9 MHz) marked with color/symbol combinations unique to each capture site to allow visual identification of individuals; ewes were also eartagged using color/number combinations unique to each capture site. Radiocollared ewes were monitored irregularly to detect mortality and movements between February and May. To aid in planning further captures and in refining design of the field monitoring phase of this management experiment, pretreatment data were gathered from May to'present. Telemetered ewes were ·located and observed every 2-4 weeks. Location (by UTM coordinate) and .presence o~ absence of a -mrr s Lng lamb was recorded for each observa t Lon, All field data were transcribed into a computerized database to aid in mapping seasonal range movements and determining preliminary lamb survival rates. RESULTS AND DISCUSSION Fifty adult ewes were captured at 4 sites, 2 (Cotton Gordon's, Sugarloaf Mountain) in.the Tarryall and 2 (Chalk Creek, Cottonwood Creek) in the Collegiate Mountains (Table 1). At least 2 ewes died as a direct result of capture, and 2 others have died since capture. Further attempts to collar ewes were thwarted by unfavorable weather that precluded helicopter flights and by impending lambing seasons. Additional capture attempts are planned for late summer and/or for ~id-November after big game seasons close. Overall, 31 of 46 surviving ewes (67%) were observed either lactating (n-ll) or nursing lambs (n-20) during May and/or June; 6 ewes showed no evidence of lambing, and the status of 9 others remains undetermined (Table 1). Only 1 known lamb loss, presumed a mortality, has been detected to date. Movements have varied widely both among and within monitored herds. A summary of field observations follows: COLLEGIATE - Chalk Creek Ewe P was found dead about 200-300 m northeast of the Chalk Creek bait site on 15 May; she may have fallen from a cliff, and appeared to have died >2 weeks earlier. All 10 remaining collared ewes in this area have been seen with lambs and·appear to he lactatiD:g ("circle";· "square", "tria~gle", 1, 2, 4, 5, 6, 7, and E), and 6 of these ("square", 2, 4, 5, 6, and 7) have been observed nursing lambs. Ewe 2's lamb apparently disappeared in late �128 June -- she was observed on 10 July for 2.5 hours and was alone for the entire time. Six of these ewes ("square", "triangle", I, 5, 6, and E) currently inhabit Cascade Canyon. The other 4 ("circle", 2, 4, and 7) seem to travel back and forth from the Brown's Creek area to private salt licks near the Love Ranch Meadow. - Cottonwood Creek Five of the 13 collared ewes have been seen with lambs and appear to be _ lactating ("square", 1, 4, 9, and E), and 3 of these ("square", 4, and 9) have been observed nursing lambs. Four ewes (2, 5, 6, and 7) are not lactating and do not appear to have lambs (ewe 7 showed teats but no udder development in June, suggesting she may have lost her lamb before monitoring began). The status of 4 ewes ("circle", "triangle", 8, and H) is unknown; 3 of these ("circle", "triangle", and 8) have been observed in ewes/lambs groups, but their individual status co~ld not be determined. Ewe H has not been seen. The sheep in this area are quite mobile and travel in large groups of >30 individuals. They have been moving back and forth between Mount Yale and a natural salt lick near Cottonwood Hot Springs. TARRYALL - Cotton Gordon's Nine of 15 collared ewes in this group have been seen with lambs and appear to be lactating ("circle", "square", "triangle", I, 6, 7, K, U, and X); 5 of these ("square", I, 6, U, .and X) have been observed nursing lambs. None of these ewes appear to have Los t,iambs. to date. The other 6 collared ewes in this area have not been seen -with lambs (2, 4; 8, 9, M, and T). Ewes 8 and 9 are not lactating and do not appear to have lambs. Ewes M and T didnot have lambs with them when seen on 5 June, and ewe 4 did not have a lamb with her when seen on 7 June, but lactation status for these ewes remains undetermined. Ewe 2 (a 2-yr-old) has been seen with other ewes and lambs, but has not been observed lactating or nursing a lamb. It appears that most of these ewes lambed on south facing slopes northeast of the Tarryall River and Carpenter Ranches (Hay Creek area) in early June. After lambing, they moved into the Goose Creek drainage (approx. 1-3 km northeast of Goose Creek Trailhead) in mid-June, then moved back into the Hay Creek area at the end of June. - Sugarloaf Mountain Ewe "square" was found dead on 22 May about 1.2 km northeast of the Sugarloaf bait site. She was found under a tree, had died without apparent struggle, and appeared to have died about 1 to 2 weeks earlier. Six of the 8 remaining collared ewes in this group appeared to be lactating and have been seen nursing lambs ("circle", ~triangleW, I, 4, 5, and R). Ewe T did not have a lamb when observed on 2 June, but appeared to be lactating. The status of ewe 2 is unknown -- she was seen only once on 23 May. This ewe group was observed in the area between "X-rock" and Sugarloaf Mountain near the Tarryall River Road in late May and early June, and then moved over McCurdy Mountain into an area around the intersection of Lost and--McCurdy Creeks. They--have remained in this area ·since early .June-Although it appears to be a lambing area, only 1 lambing (ewe "circle") has been confirmed at this site -- the other ewes had already lambed when first observed in this area in late May. �129 Intensive monitoring will continue through September with emphasis on documenting movements and survival of known lambs. Additional monitoring is also planned for November-December in preparation for initiation of experimental treatments in late December. LITERATURE CITED Bailey, J. A. 1990. Management of Rocky Mountain bighorn sheep herds in Colorado. Colo. Div. Wildl. Spec. Rep. 66, Colo. Div. Wildl., Denver. 24pp. Buechner, H. K. 1960. The bighorn sheep in the United States, its past, present, and future. Wildl. Mono. 4:74. Forrester, D. J. 1971. Bighorn sheep lungworm-pneumonia complex. Pages 158-173 in J. W. Davis, and R. C. Anderson, eds. Parasitic Diseases of Wildlife. Iowa State Univ. Press, Ames. Schmidt, R. L.,·C. P. Hibler, T. R. Spraker, and W. H. Rutherford. 1979. An evaluation of drug treatment of lungworm in bighorn sheep. J. Wildl. Manage. 43:461-467. Spraker, T. R., and C. P. Hibler. 1982. An overview of the clinical signs, gross and histological lesions of the pneumonia complex of bighorn sheep. in J. and G. G. Schoonveld, eds. Proc. Bienn. Symp. N. Wild Sheep 3:163-172. Wildlife Researcher �130 Table 1. Summary data for individual bighorn ewes captured for use in experimental evaluation of alternatives strastegies for lungworm treatment. COLLEGIATE - CHALK CREEK1 FREQUENCY COLLAR -SEX EARTAG AGE LAMBING STATUS 149.040 BLUE • YEL 12 F 5+ Lactating. .080 BLUE 13 F 5+ Nursed lamb. .100 • BLUE 14 F 5+ Lactating. .120 BLUE 1 2 F 4+ Lactating. .148 BLUE 2 3 F 4+ Nursed lamb; lamb lost. .180 BLUE 4 15 F 4+ Nursed lamb. .202 BLUE 5 5 F 4+ Nursed lamb. .220 BLUE 6 6 F 5+ Nursed lamb. .240 BLUE 7 16 F 6+ Nursed lamb. .318 BLUE E F 4+ Lactating. 1 1 Blue/white collars; freq. 149.040 - 149.492; black/yellow eartags; trapped 28 February 1991 (7 E; 2 L; 2 R); additional ewes darted 11-20 March 1991. COTTONWOOD CREEK2 COLLEGIATE FREQUENCY COLLAR 149.520 BLACK • .540 BLACK • .560 BLACK .•. .582 BLACK .620 EARTAG RED 8 SEX AGE LAMBING STATUS F 4+ Undetermined. 13 F 4+ Nursed lamb. 9 F 5+ Undetermined. 1 14 F 3+ Lactating . .BLACK 2 20 F 3+ Not lactating; no lamb . .642 BLACK 4 10 F 4+ Nursed lamb. .660 BLACK 5 17 F 5 Not lactating; no lamb. .697 BLACK 6 15 F 2 Not lactating; no lamb. . 722 BLACK 7 11 F 3 Not lactating; no lamb . .740 BLACK 8 6 F 5+ Undetermined. .782 BLACK 9 19 F 2+ Nursed lamb. .800 BLACK E 12 F 6 Lactating . .820 BLACK H F 2 Undetermined; not seen . 2 Black/yellow collars; freq. March 1991 (13 E; 7 L; 1 R). 1 148.520 - 148.980; wh1teJred eartags; trapped 16 �131 TARRYALL - COTTON GORDON' S3 FREQUENCY COLLAR EARTAG • • SEX AGE LAMBING STATUS F 3.5 Lactating. 9 F 3.5+ Nursed lamb. 10 F 5.5+ Lactating. 1 29 F 2.5 Nursed lamb . BlACK -2 5 F 1.5 Undetermined . .120 BlACK 4 31 F 2.5 Undetermined. .160 BlACK 6 25 F 4.5 Nursed lamb . .180 BlACK 7 38 F 3.5+ Lactating. .200 BlACK 8 23 F 4.5 Not lactating; no lamb. .220 BlACK 9 12 F 1.5 Not lactating; no lamb. .302 BlACK K 6 F 3.5 Lactating. .340, BlACK M 3 F 6.5+ Undetermined. .418 BlACK T 48 F 3.5+ Undetermined. .440 BlACK U 32 F 3.5 Nursed lamb . .460 BlACK X· 27 F 3.5 Nursed lamb. 148.020 BlACK -.040 BlACK .060 BlACK ••• .080 BlACK .100 YEL 43 3 Black/white collars; freq. 148.020-148.460; black/yellow eartags; trapped 21 February 1991 (16 E; 12 L; 6 R) TARRYALL - SUGARLOAF MOUNTAIN4 FREQUENCY COLLAR AGE LAMBING STATUS EARTAG SEX OR 35 F 2+ Nursed lamb. F 5 Nursed lamb. 149.530 BlACK .580 • BLACK ••• .600 BLACK 1 6 F' 5 Nursed lamb. .620 BLACK 2 7 F 3+ Undetermined. .642 BlACK 4 4 F 4 Nursed lamb. .660 BlACK 5 10 F 4 Nursed lamb. .880 BlACK R 49 F 5+ Nursed lamb. .940 BlACK T 28 F 2 Lactating. 38 4 Black/b1ue collars; freq. 149.500-149.999; black/orange eartags; trapped 9 March 1991-(9 E; 13 L· .' 4 R). ��133 Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~ _ Project No. W-1S3-R-4 Mammals Research Work Plan No. 2A Mountain Sheep Investigations Job No. 8 Statewide Mountain Sheep Management Plan Period Covered: Author: July 1, 1990 - June 30, 1991 N. Thompson Hobbs, Michael W. Miller Personnel: D. Reed Abstract A survey of attitudes on management of mountain sheep populations revealed differences in opinion among the general public, mountain sheep hunters, and D·ivision of .Wildlife employees. The public at'large tended to disapprove of hunting of mountain sheep,-particularly hunting .~or·trophies and huriting ewes. Hunting rams is strongly supported by mountain sheep hunters, but they expressed some disfavor for ewe hunting, even if they knew it would be inexpensive and would help prevent disease outbreaks in bighorn populations. Division of Wildlife (DOW) employees held beliefs intermediate to those of the general public and mountain sheep hunters. Hunters and the general public expressed strong approval for current management programs for mountain sheep. However, in the case of the general public, it was clear that their approval was not based on knowledge of DOW actions. We developed a discrete-time, stochastic simulation model to represent interactions between Pasteurella spp. and mountain sheep (Ovis canadensis) populations. Our model is derived from a system .~'f.differential equatri.ons describing dynamics ~f susceptible,· immune, and recovered (S~R) compartments in a popUlation. Our model differs from the SIR·approach, however, in that we represent compartments as states within individual animals and represent flows among compartments as probabilities of transitions among states. Results of simulations averaged over several populations showed Pasteurella spp. regulating bighorn numbers at a steady state approached via damped oscillations. This result closely resembled the outcome of the SIR model. However, because our model is stochastic, single populations showed a broad range of dynamical behavior including exponential growth, stasis, and episodic crashes in abundance. Equilibrium never prevailed. We surmise from our simulations that fluctuations in bighorn abundance can be plausibly explained by internal properties of host-pathogen interactions. External forces, including habitat degradation and fragmentation, environmental stress, and contact wi~h domestic animals axe.not necessary to p~oduce periodic epizootic. ��135 STATEWIDE MOUNTAIN SHEEP MANAGEMENT PLAN N. Thompson Hobbs Michael W. Miller P. N. OBJECTIVES 1. Develop a model of disease transmission in mountain sheep populations simulating alternatives for disease management. 2. Develop a Statewide Mountain Sheep Management Plan incorporating modeling results, information from the scientific literature, and input from organizational units. 3. Present Management Report to organizational units and interested publics. METHODS AND MATERIALS Opinion Survey We surveyed the general public, mountain sheep hunters, and Division of Wildlife (DOW) employees to identify issues likely to affe~t mountain sheep management during the coming decade. We chose to sample these three groups based on the following reasoning: The DOW is mand~ted to serve the public in .Colorado. Understanding the beliefs and values of those we serve will facilitate setting meaningful objectives for bighorn management and will help identify political and sociological constraints on meeting those objectives. Mountain sheep hunters take a somewhat greater interest in how mountain sheep are managed than does the public at large. Because of this interest, and because these hunters represent clients we sere directly, their views are also critical to guiding our future management. Finally, we chose to sample DOW employees because our own beliefs are likely to influence how we manage. In formulating strategies and tactics for managing Colorado's wildlife, we need to be particularly mindful of how our own beliefs differ from those of the people we serve. Surveys were conducted by Standage Accureach using telephone interviews .. Five hundred members of the general public were chosen at random from telephone directories; 125 mountain sheep hunters were selected from records of license holders, and 100 DOW employees were chosen from a personnel roster. Survey questions were written to obtain responses in 4 general areas: 1) quality of service provided by the DOW, 2) values and beliefs about mountain sheep populations, 3) attitudes on bighorn management, and 5) willingness to pay for mountain sheep management via alternative funding. The survey included 12 questions and took about 15":20 minutes to deliver. Simulation Model The classical model of transmission of microparasites- (viruses, bacteria, . etc.) in animal populations represents interactions of 3 pools within a host �136 population (Anderson and May 1979, May 1983, May 1986, Hassell and Anderson 1989, Anderson 1991). These pools include animals that are susceptible to infection (S), those that are infected and infectious (I), and those that have recovered from the disease and are immune to it (R) (hence, the acronym for the model, SIR). At any given time, the sum of these 3 compartments gives the total number of animals in the population, i.e., (1) Changes in the sizes of these compartments over time can be specified in three, coupled differential equations: tiS dt = a (S+I+R) ~~ = -bS-~SI ~SI- (cub+l) dR dt = I (2) (3) (4) lI-bR where a is the per capita rate of birth, b is the per capita rate of death from causes other than disease, B is a transmission coefficient, a is the disease induced mortality rate, and 1 is the ra~e of recovery from disease. Productipn of new infections is given by the average number o~ infective contacts per infected-(i.e. clinically ill) animal per unit time (p) multiplied by the total number of contacts between infected and susceptible individuals (SI). The transmission coefficient, p, is roughly analogous to the searching efficiency of a predator in simple predator-prey models (Hassell and Anderson 1989, Anderson 1991); its ~eciprocal is proportional to the time between infectious encounters (Anderson et al. 1981). In the case where immune animals are also infective (i.e. carriers), a second transmission term (e) can be applied to produce infections as a result of contacts between recovered and susceptible individuals (eSR) (Cooke 1982). The SIR model depends on assumptions that are inappropriate for mountain sheep. For example, we must assume that populations mix homogeneously and instantaneously (Bailey 1975). This assumption fails when social structures and movement patterns restrict contacts among individuals (May 1986, Mollison 1987, Andreasen and Christiansen 1989). More importantly, like all compartment models, the SIR model offers highly misleading results when applied to small, local populations because it allows pool sizes and flows among pools to fall to levels of less than one animal. This allows steady states to occur in models that would not occur in nature. These problems motivated us to develop an individual-based (Ackerman et al. 1984, Huston et al. 1988), discrete-time formulation that applies to small populations (e.g. 10-1,000 animals) characteristic of mountain sheep; and that relaxes assumptions on mixing. There are other discrete alternatives to the SIR model (e.g., Olsen et al. 1988), but these assume a constant flow of new infectives into the population, an assumption we wished to avoid. Our model is based on the following rules.- Infected animals t~ansmit infection to'susceptible animals at a high rate; and recovered animals transmit infection to susceptible animals at a relatively low rate. Once �137 infected, an animal can recover or die. Recovered animals cannot become infected again. These rules follow from observations of pasteurellosis in both mountain sheep and domestic ruminants. Mountain sheep with clinical pasteurellosis consistently shed bacteria in nasal secretions (Onderka and Wishart 1984, Miller and Hobbs 1989, Miller et al. 1991, Wild and Miller 1991), but Pasteurella spp. are recovered from nasal secretions of healthy mountain sheep relatively infrequently (Dunbar et al. 1990, Miller et al. 1991, Wild and Miller 1991). Infection with Pasteurella spp. may convey lasting immunity to recovered animals (Confer et al. 1984, Cho and Jericho 1986, Donachie et al. 1986, Confer 1988, Miller et al. 1991), but apparentlyimmune mountain sheep remain weakly infective after they recover from the disease -- bighorn lambs ,and subadults have developed clinical pasteurellosis when exposed to symptomless ewes who had recovered from this disease several years before (Miller and Hobbs 1989, Miller et al. 1991, Wild and Miller 1991). Such lifelong infectivity is not unusual for bacterial diseases (Smith 1982). Our model represents changes in the disease state of individuals. At any given time, an individual can be susceptible or infected or recovered. The model tracks the state of each animal and represents dynamics of the population by summing over all individuals at the end af each time step. Individual states are analogous to pools in the SIR model, and changes in state are analogous to flows. Transitions in state are regulated by probabilities derived from the turnover rates used in the SIR model. Deriving probabilities in this way allows state transitions of large populations to be directly comparable,to flow rates in the SIR model (Ackerman et al. 1984, King 1991). ' Hence, although our model is stochastic and the SIR model is deterministic, both models can be based on the same parameter values. For example, Equation 3 represents deaths of infected animals as a first order process. It follows from this representation that the probability that an animal remains in the infected pool (i.e., remains alive) after t units of time following infection is P{infected) t = (5) e-ct• where lla is the average life expectancy of an animal that eventually will die of 'the disease, as in the SIR model. If time periods are discrete and independent, Equation 6 can be used. to calculate the probability that an individual animal dies during each time step: PUnfected - dead) = (6) l-e-C, Following the same logic, we can derive the probability of recovery and of transmission. Given that an animal is infected at the beginning of a time step, then the probability that it recovers during that time step is PUnfected - recovered) = (7) l-e-1 �138 where 1/1 is the mean duration of infection of animals that will eventually recover. Similarly, given that an animal is susceptible at the beginning of a time step, the probability that it is infected at the end of the time step is P(susceptible~infected) = 1- (e-1I1 • e-er) (8) where P is the average number of infections produced per infected animal per unit time, e is average number of infections produced per recovered animal per unit time, i is the number of infected animals encountered by a susceptible individual and r is the number of recovered animals encountered by a susceptible individual. In our model, the number of encounters during each time step is determined by the average group size (gs). For each infected and recovered animal, a random draw of gs individuals from the current population determines which animals are encountered. In addition to its disease state, each individual in the population has states for sex (male or female) and for age (lamb, yearling, adult). Births and deaths due to causes other than disease (Jorgensen.and Wishart 1986), as well as the sex of offspring, are determined using the probabalistic approach outlined above. Changes in state are determined for each animal by comparing the transition probabilities to random deviates drawn from a uniform distribution with endpoints. 0 and 1 (Ackerman et al. 1984). Thus, our algor~thm requires cy~ling through all "animals in the populatj.on at each time step. Disease states of individuals are updated weekly; births and deaths due to causes other than disease are updated annually. We estimated parameter values for p, e, a, and 1 based on observed duration of infections and life expectancy of captive mountain sheep infected with Pasteurella spp. (Miller and Hobbs, unpubl.), and on time series data for pasteurellosis outbreaks in wild bighorn popUlations (Simmons 1982, Festabianchet 1988). Estimates of P and e are particularly coarse, and may not be reliable for quantitative predictions. However, we believe they allow an adequate starting point for examining qualitative behavior. Values for life history parameters of mountain sheep were set to produce an average intrinsic rate of increase of 0.12 (Haas and Decker 1980, Jorgensen and Wishart 1986). For simplicity. we did not represent density-dependent effects on birth and death rates. This means that in th~ absence of disease, simulations would produce exponential growth. RESULTS AND DISCUSSION Opinion Survey As in past surveys, the DOW received high levels of public approval. Sixtythree percent of the public at large and 74% of mountain sheep hunters reported a generally favorable impression of the DOW (Appendix, Table 1). SJmilar approval ratings were given for managing big game hunting, fishing opportunity, and mountain sheep populations (Appendix, Table 3). Both of our constituent groups expressed a high level of trust in bur ability to manage mountain sheep "effectively and correctly" (Appendix, Table 3). However, this �139 was despite the fact that 40% of the general pubic reported that they did not know much about us (Appendix, Table 4). These responses suggest that for much of the public, we do a good job of projecting an "image" to the public without communicating information on precisely what we do. On the other hand, 81% of mountain sheep hunters said they knew a great deal or quite a bit about the DOW. Thus, bighorn hunters believe they are quite knowledgeable about our activities, the general public appears to know substantially less about us, but both groups hold us in high regard. The survey revealed a marked discrepancy between the general public and mountain sheep hunters on why they value mountain sheep (Appendeix, Table 5). Over 80% of the public believed that "...the value of mountain sheep as a part of a camping and backpacking experience exceeds the animal's value for sport hunters.", while only 20% of bighorn hunters believed this to be tue. DOW employees were evenly split on this issue. No other question produced such a polarization among the 3 populations sampled. In contrast, there was strong agreement among the 3 populations on the statement "I may never see a mountain sheep in the wild, but it-is very important for me to know that they exist in Colorado." (Appendix, Table 5). Over 80% of all 3 groups expressed some level of agreement with that statement. We interpret this to mean that all of the people we serve want to see viable bighorn populations in Colorado for their cultural and heritage values. On the other hand, the people we serve disagree about the relative importance of consumptive vs. non-consumptive values. Knowledge of mountain sheep biology differed among sample groups. A sub~tantial proportion of all 3 groups sampled knew that the status of mountain sheep had improved in Colorado since 1970 (Appendix, Table 6). However, over 60% of the public believed that "Mountain sheep are among the endangered species in Colorado", while in excess of 75% of bighorn hunters and DOW employees realized this was not the case (Appendix, Table 7). This may reflect some misunderstanding about the meaning of "endangered species", because only 45% of the public surveyed believed that "...mountain sheep populations will disappear in many parts of Colorado in the next ten years." It was also not widely understood by the public that, "Mountain sheep are likely to have more diseases than most other wildlife." Over 80% of bighorn hunters and about half of DOW employees recognized that disease was a particularly important problem for mountain sheep. These responses indicate that the general public and mountain sheep hunters have strong opinions on the value of mountain sheep populations. However, the public is not particularly knowledgeable about biological problems confronting mountain sheep, while hunters appear to have somewhat greater understanding of those problems. It should be emphasized that a significant portion of the public seems to believe that survival of mountain sheep as species is one of the important issues in bighorn management. Mountain sheep hunters and DOW employees believed that this is not a particularly important problem. The schism in consumptive and non-consumptive values between the general public and mountain sheep hunters was also reflected in specific attitudes about hunting. Eighty-five percent of the general public opposed hunting bighorn rams as trophies, and 78% opposed hunting rams for recreation. We asked the question about recreational val--ueof hunting rams in--two forms (Appendix, Table 9 and 10). Regardless of how we asked the question, 70% or more of the general public opposed hunting rams as "sport" or "recreation" (Appendix, Table 9 and 10). However, opposition was less strong to hunting �140 rams as a source of food. About half of the public was opposed to " ...hunting adult male mountain sheep as a source of food"; about half were in favor. There was no clear trend in opinions on hunting relative to age of respondents in the general public. The proportion of the population opposed to hunting rams was quite uniform across all age groups. It was not surprising that mountain sheep hunters strongly supported recreational hunting and hunting for food. DOW employees expressed similar support for these types of hunting. However, a surprisingly large proportion of bighorn hunters (27%) and DOW employees (34%) opposed hunting rams as trophies. With respect to hunting females, we asked bighorn hunters whether they would buy a ewe license for $25. Sixty-two percent of bighorn hunters said it was not at all likely they would do so (Appendix, Table 12). Knowledge that ewe hunting might be important to reducing disease outbreaks did not appreciably change this ambivalence (Appendix, Table 13). The lack of interest in ewe hunting was attributable to a competing interest in hunting for trophies (40% of those who wouldn't buy a ewe license) as well as to the belief that ewe hunting reduces the population (35% of those who would not buy a license) (Appendix, Table 14). Twenty-three percent of bighorn hunters who would not buy a ewe license opposed ewe hunting as a matter of principle (Appendix, Table 14). We focused several questions on specific approaches to managing disease in bighorn populations (Appendix, Table 15): Over 80% of all 3 populations approved of "Placing some mountain sheep in captivity for disease resear~h purposes." Among mountain sheep hunters and DOW employees~ there was also relatively high approval for "Increasing habitat for mountain sheep, even though it could be harmful to some habitat used for other wildlife, such as deer." (Appendix, Table 15). The general public was less supportive of such actions. Seventy-three percent of bighorn hunters approved of using ewe hunting to control disease (Appendix, Table 15). However, remember that despite this view, only 26% of bighorn hunters were likely to buy a ewe license (Appendix, Table 13). DOW employees expressed similar approval of ewe hunting (62%). Forty-two percent of the general public was opposed to ewe hunting (even as part of an effort to reduce disease); 22% were srrongly opposed to ewe hunting (Appendix, Table 15). We pointed out to all persons surveyed that the preponderance of financial support for bighorn management in Colorado came from hunting revenues. We asked whether they felt bighorn management should depend on license sales. Sixty-one percent of the general public and over 80% of bighorn hunters and DOW employees felt that mountain sheep management should be supported by" ... some sort of contribution" from funding sources other than sale of hunting licenses. However, this left 39% of the public believing that bighorn management should depend entirely on hunting revenue. This is problematic in light of the opposition to hunting expressed by most of the public. Of those who supported alternative funding sources, there was strong support for using general fund revenues, unredeemed bottle return deposits and tax check-offs to pay for mountain sheep management. There was not strong support for generating additional revenue by taxes on sporting goods or for users' fees on public land. Several political issues are likely to impact the ability of the DOW to manage mountain sheep populations in Colorado during the coming decade. The general public and bighorn hunters hold sharply different opinions on the objectives �141 population density. However, declines in the number of recovered animals resulting from natural mortality opposed these trends, and occasionally allowed the population to escape the regulating effects of disease (Fig. 2A). The magnitude of simulated disease outbreaks was strongly dependent on time since the previous epizootic. This dependence resulted because the frequency of disease-induced deaths during a simulated epizootic increased in proportion to the number of susceptible animals available for infection. The susceptible pool increased as long as the population remained disease-free. Consequently, long intervals between epizootic were associated with high levels of diseaseinduced mortality during previous epizootic. During the last century, bighorn populations have fluctuated unpredictably, largely as a result of episodic outbreaks of disease and parasitism. Many workers believe that fluctuations in bighorn numbers are ultimately caused by changes in their habitats. Disease is seen as a proximate symptom of deficiencies in habitat resources; these deficiencies include poor forage conditions (Stelfox 1976), lack of migration corridors (Risenhoover et al. 1988), and excessive disturbance from man (Sprake~ et al. 1984). This view holds that the dynamics of diseases in mountain sheep populations are ultimately driven by extrinsic forces like plant succession (Risenhoover and Bailey 1985, Wakelyn 1987, Risenhoover et al. 1988), human encroachment on traditional ranges (King and Workman 1986) and recurrent interactions with domestic livestock (Goodson 1982, Foreyt and Jessup 1982, Onderka and Wishart 1988,'Foreyt 1989, C~llan et al. 1991). Our view differs. Onc~.Pasteurella spp. are introduced'into a bighorn' population by domestic livestock our other means, our model illustrates that 2 simple assumptions on disease transmission are sufficient to produce local epizootic at irregular intervals. We show that disease-induced fluctuations can result whenever 1) infected animals transmft disease at high rates and 2) immune animals transmit disease at low rates. High rates of transmission between infected and susceptible animals ~plify the effect of an initial infection and allow disease to spread geometrically among susceptible individuals once a single animal becomes infected. A low rate of transmission between immune and susceptible animals following an epizootic delays the onset of another outbreak and allows large numbers of susceptible individuals to accumulate in a population. The tension between these two routes of transmission produces unpredictable cycles of population growth and decline (Fig. 2A-C). Our assumptions appear quite plausible for Pasteurella spp. infections in mountain sheep. Many animals that show no signs of disease harbor Pasteurella spp. in their tonsils (Rosen 1981, Onderka and Wishart 1988, Dunbar et al. 1990, Wild and Miller 1991). When this is the case, the probability of transmission of Pasteurella spp. to another animal is extremely low. However, when animals are clinically ill, then Pasteurella spp. are abundant in nasal exudates (Rosen 1981, Onderka and Wishart 1984, Onderka and Wishart 1988, Miller and Hobbs 1989, Miller et al. 1991, Wild and Miller 1991). As a result, coughing and nasal discharge associated with illness dramatically increase the likelihood of transmission (Rosen 1981). We believe this simple, physical mechanism can explain many of the dynamics of disease outbreaks in mountain sheep. We invoke stochast Icf.cy to explain these"dynamics, but it Ls--also possible that disease outbreaks are deterministically chaotic (Aron 1984, Schwartz 1985, Olsen et al. 1988, O'Lseri and Schaffer 1990). Although data on mountain sheep are inadequate to distinguish between chaos and noise, we emphasize that �142 for bighorn management and disagree on the role of hunting in meeting those objectives. Although there was a broad consensus among all groups surveyed that mountain sheep were highly valuable in their own right, bighorn hunters favored management that includes hunting as a primary use of mountain sheep, while the public at large seemed to favor managing mountain sheep to enhance their value as part of other recreational pursuits, like camping and backpacking. As a result, the appropriate goals for bighorn management are not particularly clear. There is also disagreement about what management tactics are appropriate in achieving those goals. Harvest is a important tool in managing mountain sheep as well as other wild ungulates. However, the general public does not strongly support hunting bighorn males or females. Bighorn hunters failed to show strong support for ewe hunting, even if it were needed to prevent disease outbreaks. These responses emphasize that using harvest to regulate the distribution and abundance of bighorn populations may not be feasible in the foreseeable future. It is certain, however, that continued harvest of rams and expanded harvest of ewes will depend on documenting benefits of hunting relative to specific objectives for bighorn populations. For example, if we believe that hunting is needed to reduce the frequency and magnitude of disease outbreaks, then we will need to convince the public and sport hunters that this is the case. In the absence of convincing arguments we may face stout political opposition from the public and lack of meaningful participation from bighorn hunters. Simulation Model Individual-based simulations produced episodic, self-limiting epizootic (Fig. 1). Outbreaks of disease were initiated by conversion of a single animal from the susceptible state to the infected state after contact with a weakly infective, recovered animal. Because susceptible animals were much more likely to become infected after contact with an infected animal than after contact with a recovered one, the addition of a single infected animal into the population caused a rapid increase in the likelihood of new infections. If the infected animal transmitted the disease before it died, then a geometric rise in the number of infected animals usually ensued, resulting in -a full-blown epizootic with high mortality. As time passed, the decline in the number of available susceptible animals and the recovery or death of infected animals acted collectively to reduce disease transmission. As the number of new infections approached 0, the population stabilized at a new, reduced level. These dynamics depended only on the probabilities of changes in state and were not driven by any external processes. Epizootics caused dynamic, varied behavior in simulated mountain sheep populations. We ran simulations to represent 20 separate populations over 50 years. All populations had the same transition probabilities and differed only in the series of random numbers used to drive state transitions. Trajectories of these populations included exponential growth following stasis (Fig. 2A), cycles (Fig. 2B), and erratic fluctuations following exponential growth (Fig. 2C). Final populations sizes varied from 100 to 1,500 animals. However, when we averaged results over all populations, our model approached an equilibrium of about 200 animals via damped oscillations (Fig. 2D). This behavior resembled the approach to steady state predicted by the SIR model. �143 t/J ...J -e ~ Z 400 -- ---" 300 < II. 0 ffim . 100 SUSCEPT. .6 , \ \ o6o6 ~ 2 RECOV. " ,, ,, ,, 200 .• ~-- ,' .•. ! __ -~- 0 0 5 TOTAL 10 __ INFECT • ---------- •....t...•...•... 15 20 25 WEEKS Figure 1. Changes in numbers of susceptible. infected. and recovered mountain sheep during the course of a simulated epizootic initiated by infection of a single susceptible animal following contact with a recovered animal in year O. Final steady state included 6 susceptible animals; all other survivors were immune and weakly infectious. Figure 2. A-C. Simulation output for individual populations given identical parameter values and different random number seeds. Three infected animals were introduced to each population at year O. Parameter values for disease dynamics were ~ - 0.10 animal weeks", e - 0.0001 animal weeks", 1 = 0.125 weeks", & - 0.5 weeks". ~ - 10 animals. D. Simulation output averaged over 20 individual populations. Steady state conditions illustrate the ability of disease to regulate population growth. In the absence of disease, growth would have been exponential. The occurrence of simulated disease outbreaks was weakly dependent on time since the previous epizootic. This was the case because the number of susceptible animals relative to the number of recovered animals fell to a local min:i,mumimmediately aft~:ran epizootic and .i.ncreasedthereafter. As the number of susceptibles increas~d. the ratio of susceptible to recovered animals within a group also increased. As a result, the contact rate between individuals harboring disease and those susceptible to it tended to rise with �144 both processes are internally driven and do not require external driving forces. Thus, if the behavior of our model is faithful to processes in nature, then external forces like environmental stress and habitat loss are not necessary to sustain episodic outbreaks of disease in wild bighorn populations. This does not mean that changes in habitat cannot influence the frequency and intensity of epizootic by influencing transmission and pathogenicity. But it does mean that restoration of pristine habitat conditions, elimination of ~stress", and segregation of mountain sheep from domestic livestock would not necessarily eliminate disease cycles from many established bighorn populations. Pasteurella spp. appear to be thoroughly endemic in many mountain sheep populations in North America -- if our assumptions on the mechanism of transmission are correct, then we should probably expect that even the best-managed herds will experience epizootic (e.g. Bailey 1990). Our simulations offer several important cautions for revealing cause and effect in bighorn population dynamics. Internally driven cycles offer tremendous opportunity for spurious correlation with external conditions and events. Consider a population regulated as in Fig. 2A. If we began treating the population for parasites during year 25 and observed its subsequent _ growth, we might be severely tempted to assume that treatment improved the population's performance. Similar problems can arise in evaluating bighorn popUlations established by relocation. Given the diversity of trajectories that we might expect from populations regulated by the mechanisms we propose (Fig. 2A-C) , we should anticipate high variability in performance among transplanted ~heep herds. Such variability is commonly observed (e.g. Bailey 1990). However, differences in performance among transplanted h~rds m~y be only weakly related to habitat conditions, environmental s trre ssoxs , genetic heterozygosity, or other factors that are often invoked to explain the success (or failure) of transplants. Our simulations emphasize that separating the effects of disease from the effects of other influences on bighorn population dynamics will require careful experimental design and large samples. We are likely to be misled by anything less. It is becoming increasingly clear that population models based on the behavior of individuals offer qualitatively different results than models based on molar, average behavior (Lomnicki 1988, May and Southwood 1990). At regional scales, our model suggests that disease can suppress the growth of metapopulations of mountain sheep and can maintain steady state conditions (Fig. 2d). At local scales, however, disease appears to produce dramatic fluctuations in animal numbers (Fig. 2A-C). Contrast between regional and local behavior has emerged as a pivotal feature of populations of plants and animals in nature (Wiens and Rotenberry 1981, Allen and Starr 1982, Shugart and Urban 1988, Hanski 1991, Verboom et al. 1991). Many management decisions on ungulates are inherently local in scope, but the inferences of molar population models may not be appropriate on local scales. Such models offer inferences on "average behavior", while managers must often respond to the variation that creates the average. We believe that the concept o~ equilibrium derived from molar models, a concept that dominates thinking on regulation of animal numbers (Sinclair 1989), may rarely apply to the local dynamics of mountain sheep popUlations affected by disease. LITERATURE CITED Ackerman, E., L. R. Elveback, and J. P. Fox. 1984. Simulations of Infectious Disease Epidemics. Charles Thomas, Springfield, IL. 202pp. �145 Allen, T. F. H., and T. B. Starr. 1982. Hierarchy: perspectives for ecological complexity. Univ. Chicago. Press, Chicago. 310pp. Anderson, R. M. 1991. Populations and infectious diseases: ecology or epidemiology? The eighth Tansley lecture. J. An. Eco1. 60:1-50. Anderson, R. M., and R. M. May. 1979. Population biology of infectious diseases: Part I Nature 280:361-367. Anderson, R. M., H. C. Jackson, R. M. May, and A. M. Smith. 1981. dynamics of fox rabies in Europe. Nature 289:765-771. Population Andreasen, V., and F. B. Christiansen. 1989. Persistence of an infectious disease in a subdivided population. Math. Biosci. 96:239-253. Aron, J. L. 1984. Seasonality and period-doubling bifurcations in an epidemic model. J. Thero. BioI. 110:665-679. Bailey, N. T. J. 1975. its Applications. Bailey, J. A. 1990. Colorado Colo. The Mathematical Theory of Infectious Diseases and Charles Griffin and Co., London. Management of Rocky Mountain bighorn sheep herds in Div. Wild1. Spec. Rep. 66. 24pp. Buechner, H. K. 1960. The bighorn sheep in the United States, its past, present, and future. Wi1d1. Mono. 4:74. Callan, R. J., T. p. Bunch, G. W. Workman, and R. E. Mock. 19-91. Development of pneumonia .in desert bighorn sheep after exposure to a flock of exotic· wild and domestic sheep. J. Am. Vet. Med. Assn. 198:1052-1056. Caugh1ey, G. 1970. Eruption of ungulate populations with emphasis on Himalayan thar in New Zealand. Ecology 51:53-71. Cooke, K. L. 1982. Models for epidemic infections with asymptotic cases l: one group. Math. Modelling 3:1-15.. Dunbar. M. R., A. C S. Ward, and G. Power. 1990. Isolation of Pasteurella-haemolytica from tonsillar biopsies of Rocky Mountain bighorn sheep. J. Wi1dl. Dis. 26:210-213. Foreyt, W. J., and D. A. Jessup. 1982. Fatal pneumonia of bighorn sheep following association with domestic sheep. J. Wild1. Dis. 18:163-168. Forrester, D. J. 1971. Bighorn sheep lungworm pneumonia complex. Pages 158-173 in J. W. Davis and R. C. Anderson, eds. Parasitic Diseases Of Wild Mammals. Iowa State University Press, Ames. Goodson, N. J. 1982. Effects of domestic sheep grazing on bighorn sheep: review. Biennial Symp. N. Am. Wild Sheep and Goat Counc. 3:287-313. a Hanski, I. 1991. Single-species metapopu1ation dynamics - concepts, models and observations. BioI. J. Linn. Soc. 42:17-38 . .._ HasseLL, M. P .• and R. M. Anderson , 1989. Predator-prey and host pathogen interactions. Pages 147-196·in J. M. Cherret, ed. Ecological Concepts. Blackwell Scientific, Oxf'ord , �146 Houston, D. B. 474pp. 1982. The Northern Yellowstone Elk. Macmillan, New York. King, M. M., and G. W. Workman. 1986. Response of desert bighorn sheep to human harassment: management implications. Trans. N. A. Wildl. Nat Res. Conf. 51:74-85. Klein, D. R. 1968. The introduction, increase, and crash of reindeer on St. Matthew Island. J. Wildl. Manage. 32:350-367. Lomnicki, A. 1988. Population ecology of individuals. Princeton Univ. Press. 223pp. Monog. Pop. Ecol. 25. Lutz, L. L. 1970; The bighorns: wild sheep of California, part 1. Forests. 76:28-31. . Amer. May, R. M. 1983. Parasitic infections as regulators of animal populations. Am. Sci. 71:36-45. May, R. M. 1986. Population biology of microparasitic infections. Pages 405-442 in T. G. Hallam and S. A. Levin, eds. Mathematical Ecology. Biomathimatics Vol. 17. Springer-Verlag, Berlin. _____ , and T. R. E. Southwood. 1990. Introduction. Pages 1-19 in B. Shorrocks and I. R. Swingland, eds. Living in a Patchy environment. Oxford Univ. Press, Oxford. McCullo~gh, D. R. 1979. The George Res~rve deer herd: population ecology of a K- selected species. Univ. Michigan Press, Ann Ar~or. 27lpp. Mollison, D. 1987. Population dynamics of mammalian diseases. Pages 329-342 in S. Harris, ed. Mammal Population Studies. Symp. ·Zool. Soc. Lond. 58. Olsen, L. F., and W. M. Schaffer. 1990. Chaos versus noisy periodicity: alternative hypotheses for childhood epidemics. Science 249:499-504. Olsen, L. F., G. L. Truty, and W. M. Schaffer. 1988. Oscillations and chaos in epidemics: a nonlinear dynamics study of six childhood diseases in Copenhagen, Denmark. Theor. Pop. BioI. 33:244-370. Onderka, D. K., and W. D. Wishart. 1984. A major bighorn sheep dieoff from pneumonia in southern Alberta. Pages 356-363 in Proc. N. Wild Sheep and Goat Counc. 4. _____ , and 1988. Experimental contact transmission of Pasteurella-haemolytica from clinically normal domestic sheep causing pneumonia in Rocky Mountain bighorn sheep. J. Wildl. Dis. 24:663-667. Risenhoover, K. L .• and J. A. Bailey. 1985. Foraging ecology of mountain sheep ovis-canadensis implications for habitat management. J. Wildl. Manage. 49:797-804. _____ • • and L. A. Wakelyn. 1988. Assessing the Rocky Mountain bighorn sheep management problem. Wildl. Soc. Bull. 16:346-352. Rosen, M. N. 1981. Pasteurellosis. Pages 244-252 in J. W. Davis, L. H. Karstad, and D. O. Trainer. Infectious Diseases of Wild Mammals. Iowa State Univ. Press, Ames, Iowa: �147 Schwartz, I. B. 1985. Multiple stable recurrent outbreaks and predictability in seasonally forced nonlinear epidemic models. J. Math. Biol. 21:347-362. Shugart, H. H., and D. L. Urban. 1988. Scale, synthesis, and ecosystem dynamics. Pages 279-290 in L. R. Pomeroy and J. J. Alberts, eds. Concepts of Ecosystem Ecology. Springer-Verlag. New York. Sinclair, A. R. E. 1977. The African Buffalo: A Study of Resource Limitation of Populations. Univ. Chicago Press. 355pp . . 1989. Population regulation in animals. J. M. Cherrett, ed. Ecological Concepts: to an Understanding of the Natural World. Oxford. Pages 197-241 in The Contributions of Ecology Blackwell Scinentific, Smith, C. E. G. 1982. Major factors in the spread of infections. Pages 207-235 in M. A. Edwards and U. McDonnell, eds. Animal Disease in Relation to Animal Conservation. Symp. Zool Soc. Lond. 50. Spraker, T. R., C. P. Hibler, G. G. Schoonveld, and W. S. Adney. 1984. Pathologic changes and microorganisms found in bighorn sheep ovis-canadensis-canadensis during a stress-related die-off. J. Wildl. Dis. 20:319-327. Stelfox, J. G. 1971. Bighorn sheep in the canadian rockies a history 1800-1970. Can. Field. Nat. 85:101-122. 1976. Range eco'Logyof rocky mountain bighorn sheep in Canadian national parks. Pages 1-50 in Can Wildl Serv Rep Ser. (39). 1976. Turner, J. C., and J. B. Payson. 1982. Occurrence of selected infectious diseases in the desert bighorn sheep herds of the Santa-Rosa Mountains, California. Calif. Fish. Game 68:235-243. Verboom, J., K. Lankester, and J. A. J. Metz. 1991. Linking local and regional dynamics in stochastic metapopulation models. BioI. J. Linn. Soc. 42:39-55. Wiens, J. A., and J. T. Rotenberry. 1981. Habitat associations and community ·structure of birds in shrubsteppe environments. Ecol. Monogr. 51:21-41. Wild, M. A., and M. W. Miller. 1991. Detecting nonhemolytic Pasteurella-haemolytica infections in healthy Rocky Mountain bighorn sheep (Ovis-canadensis) - influences of sample site and handling. J. Wildlife. Dis. 27:53-60. Prepared by __;7\.}=-\~_.;._-=-;..;,;~~---!.]b~ N. Thompson Hobbs Wildlife Researcher _ Wildlife Researcher �148 APPENDIX Table 1. Responses of the general public and bighorn sheep hunters to the question: "In general, are your impressions of the Colorado Division of Wildlife very positive, somewhat positive, neutral, somewhat negative, or very negative?" Population Sampled Random Sample Bighorn Sheep Hunters DCN PersOfYlel Nl.Ililer Percent Nl.Ililer Percent Nl.Ililer Percent Responding Responding Responding Responding Responding Responding Impression of Division of Wi ldl ife not asked 92 18 28 22 · · Somwhat positive 225 45 65 52 134 27 18 14 · · · Neutral 30 6 10 8 · Very ne98tive 6 1 3 2 · DK/no answer 11 2 1 1 · Very positive Somewhat negative · · · · Table 2. Responses of the general public and bighorn sheep hunters to the question: "Tell me if you feel the Colorado Division of Wildlife is doing an excellent-job, good job, fair job, or poor job in: . . Managing big game hunting. Managing the bighorn sheep population in Colorado. Providing adequate fishing opportunities throughou~ the state of Colorado. Population Random Sample Sampled Bighorn Sheep Hunters DCN Personnel Nl.Ililer Percent Nl.Ililer Percent Responding Responding Responding Responding Nl.Ililer Percent Responding Responding How well does DCN manage bi 9 game? 52 10 32 26 · Good 239 48 61 49 Fair 127 26 29 23 Poor 25 5 3 2 Do not know 55 11 . . · · · · Excellent · · · · · �149 Table 2. cont. Population SiIq)led Bighorn Sheep Hunters Random S8q)le . DOW Personnel NUJi)er NUJi)er Percent NUJi)er Percent Percent Responding Responding Responding Responding Responding Responding How well does DOW manage bighorns? 60 12 56 45 · · Good 215 43 48 38 · Fair 98 20 11 9 · Poor 10 2 7 6 115 23 3 2 · · · · · · Excellent Do not know Population S8q)led Random S8q)le Bighorn Sheep Hunters DOW Personnel NUJi)er NUJi)er Percent NUJi)er Percent Percent Responding Responding Responding Responding Responding Responding How well does DOW manage fishing? Excellent · 98 20 17 14 Good 256 51 59 48 Fair 85 17 29 23 · Poor 25 5 8 6 Do not know 34 7 11 9 · · · -- · · · Table 3. Responses of the general public and bighorn sheep hunters to the question: "Do you strongly agree, somewhat agree, somewhat disagree or strongly disagree with the following: I trust the Colorado Division of Wildlife to manage bighorn sheep effectively and correctly in Colorado." Population S8q)led Random SiIq)le Bighorn Sheep Hunters DOW Personnel NUJi)er NUJi)er NUJi)er Percent Percent Percent Responding Responding Responding Responding Responding Responding I trust DOW to manage bighorns well. Strongly agree 253 51 88 70 Somewhat agree 215 43 24 19 Somewhat disagree 12 2 6 5 Strongly disagree 13 3 6 5 5 1 1 1 Do not know/No opinion · · · · · · · · · · �150 Table 4. Responses of the general public and bighorn sheep hunters to the question: "Would you say you know a great deal about the Colorado Division of Wildlife, quite a bit, some or not too nuch?" Population S~led Random S~le Bighorn Sheep Hunters DOW Personnel Nurber Percent Nurber Percent Nurber Percent Responding Responding Responding Responding Responding Responding Knowledge of Division of Wi ldl ife · · · · 24 2 100 14 11 . . · · · A great deal 22 4 26 21 Quite a bit 77 15 55 44 Some 195 39 30 Not too nuch 197 40 6 1 None (volunteered) · Table 5. Responses of the general public, bighorn sheep hunters, and Division of Wildlife (DOW) employees to the question: "Do you strongly agree, somewhat agree, somewhat disagree or strongly disagree with the following: I think the value of bighorn sheep as a part of a c~ing exceeds the animal's value for sport hunters. and backpacking experience I may never .see a bighorn sheep in the w.ild, but it is very ilJl)Ortantfor me to know that they exist in Co~orado." . " Population S8q)led. Random S8q)le Bighorn Sheep Hunters DOW Personnel Nurber Percent Percent Nurber Percent Nurber Responding Responding Responding Responding Responding Responding Nonconsumptive value exceeds hunting value. Strongly agree 284 57 10 8 20 20 Somewhat agree 127 26 15 12 31 30 Somewhat disagree 58 12 65 52 20 20 Strongly disagree 22 4 27 22 25 25 7 1 8 6 6 6 Do not know/No opinion �151 Table 4 cont. Population S~led DOW Persomel Bighorn Sheep Hunters Random SlIq)le ; Percent Nl.II1ber Percent Nunber Percent Nunber Responding Responding Responding Responding Responding Responding I value "knowing bighorns are there." Strongly agree 380 76 87 70 89 87 Somewhat agree 96 19 14 11 9 9 Somewhat disagree 11 2 12 10 2 2 Strongly disagree 8 2 6 5 1 1 Do not know/No opinion 3 1 6 5 1 1 Table 6. Responses of the general public, bighorn sheep hunters, and DOW employees to the question: "As far as you know, have the nunber of bighorn sheep in Colorado decreased, increased, or remained about the same since 19701" Population SlIq)led Bighorn Sheep Hunters Random S~le DOW Persomel Percent Nl.I1ber Percent Nunber Percent Nunber Responding Responding Responding Responding Responding Responding Status of bighorns since 19701 . .: Decreased __ Increased Remained the same Do not know 61 12 1 1 10 10 208 42 102 82 67 66 90 18 15 12 12 12 138 28 7 6 13 13 Table 7. Responses of the general public, bighorn sheep hunters, and Division of Wildlife (DOW) employees to the question: "00 you strongly agree, somewhat agree, somewhat disagree or strongly disagree with the following: Bighorn sheep are among the endangered species in Colorado. At the current rate of mortality, I think the bighorn sheep population will disappear in many parts of Colorado in the next ten years. Bighorn sheep are likely to have more diseases than most other wildlife." Population S...,led Random S...,le Bighorn Sheep Hunters DOW Persomel Nunber Nunber Percent Nunber Percent Percent Responding Responding Responding Responding Responding Responding Bighorn sheep are an endangered species. Strongly agree 106 21 4 3 9 9 Somewhat agree 201 40 7 6 7 7 Somewhat disagree 117 24 82 66 75 74 Strongly disagree 44 9 32 26 11 11 Do not know/No opinion 29 6 . . . . _-- �152 Table 7 cont. Population SiIq)led Random SlIq)le Bighorn Sheep Hunters DOW Personnel NUlber Percent NUlber Percent NUlber Percent Responding Responding Responding Responding Responding Responding Bighorn populations likely to disappear in future. Strongly agree 74 15 6 5 6 6 Somewhat agree 151 30 4 3 14 14 Somewhat di sagree 160 32 87 70 60 59 Strongly disagree 75 15 26 21 17 17 Do not know/No opinion 37 7 2 2 4 4 Population S8q)led Random SiIq)le Bighorn Sheep Hunters DOW Personnel NUlber Percent NUlber Percent Percent NUlber Responding Responding Responding Responding Responding Responding Bighorn sheep are prone to diseases. Strongly agree 51 10 68 54 Somewhat agree 123 25 35 28 . 28 27 32 31 19 19 Somewhat dis~ree 186 38 7 6 StrOngly disagree 76 15 12 10 14 14 Do not know/No opinion 58 12 3 2 9 9 Table 8. Responses of the general public and bighorn sheep hunters to the question: "Dg you favor or oppose hunting adult male bighorns to obtain a trophy?" Population Sampled Bighorn Sheep Hunters Random Sample DOW Persomel NUlber Percent Nl.Ilb!r Percent Nl.Ilb!r Percent Responding Responding Responding Responding Responding Responding Opinion hunting rams as trophies? Favor 52 10 90 72 53 52 Oppose 422 85 34 27 35 34 22 4 1 1 14 14 No opinion �:1.53 Table 9. Responses of the general public, bighorn sheep hunters, and Division of Wildlife (DOW) employees to the question: "00 you favor or oppose hunting adult male bighorns as recreation?" Population SBq)led Random S8q)le Bighorn Sheep Hunters DOW Persomel Nl.IIber Percent Nl.IIber Percent Responding Responding Responding Responding Nl.IIber Percent Responding Responding Opinion of hunting rams as recreation? Favor 86 17 105 84 79 78 Oppose 386 78 17 14 18 18 No opinion ·23 5 3 2 4 4 Table 10. Responses of the general public, bighorn sheep hunters, and Division of Wildlife to the question: (DOW) employees liDo you strongly agree, somewha.t agree, somewhat disagree or strongly disagree with the following: Hunting male bighorn sheep is a form of sport and recreation, them should be allowed to do SO." and people who want to hunt Population SBq)led Randon! SBq)le Bighorn Sheep Hunters DOW Personnel Nl.IIber· Percent Nl.IIber Percent Responding Responding Responding Responding Nl.IIber Percent Responding Responding -, People should be allowed to hunt rams. Strongly agree 52 11 111 92 70 rz Somewhat agree 95 19 8 7 14 14 Somewhat disagree 117 24 . . 5 5 Strongly disagree 227 46 1 1 7 7 2 0 1 1 1 1 Do not know/No opinion Table 11. Responses of the general public, bighorn sheep hunters, and Division of Wildlife to the question: (DOW) employees "Do you favor or oppose hunting ac:lul t male bighorns as a source of food?- Population Random SlIq)le SlIfI1lled Bighorn Sheep Hunters DOW Personnel Nl.IIber Percent Nl.IIber Percent Responding Responding Responding Responding Nl.IIber Percent Responding Responding Opinion of hunting rams as food? Favor 250 50 104 83 84 82 Oppose 221 45 18 14 12 12 25 5 3 2 6 No opinion .. _'_" 6 �154 Table 12. Responses of bighorn sheep hunters to the question: If the Colorado Division of Yildlife were to allow female bighorn sheep to be hunted in Colorado and the license fee to hunt bighorn sheep was $25, how likely would you be to buy a license to hunt female bighorns? Very likely, somewhat likely, or not at all likely? Population Random Sample Sampled Bighorn Sheep Hunters DOIJ Personnel NUJi:ler Percent NUJi:ler Percent NUJi:ler Percent Responding Responding Responding Responding Responding Responding Yould you buy a ewe license for S25? · · · Very likely Somewhat likely Not at all likely Table 13. Responses · · 33 26 1 9 15 12 3 27 · 77 62 7 64 of bighorn sheep hunters to the question: UDoes knowing that hunting female bighorn sheep would help control population size and help prevent disease outbreaks among bighorn sheep make you change your mind about how likely you would be to buy a license to hunt adult female bighorns in Colorado?" Population Random Sampl e Sampled Bighorn Sheep Hunters DOIJ Personnel Nl,IIj)er Percent Nl,IIj)er Percent NUJi:ler Percent Responding Responding Responding Responding Responding Responding Buy a eWe license (ifit reduces disease). -- Yes . No 1 Do not know 1 . 17 22 . 50 58 74 6 50 3 4 . . 100 . �155 Table 14. Responses of people who said they would not buy a ewe license to the question: "\lhich of the following statements best describes why you would not be likely to buy a license to hunt female bighorn sheep in Colorado? I am not interested in hunting female bighorn sheep because I only hunt bighorn for the trophy. I don't think adult female bighorns should be hunted because it will cause a decrease in the bighorn population. I think it is OK to hunt male bighorns. but I oppose hunting female bighorns just as a matter of principle.Population S8q)led 00\1 Persomel Bighorn Sheep Hunters Random S8q)le Percent NUlber Percent NUlber Percent NUlber Responding Responding Responding Responding Responding Responding \lhy would you not buy a ewe license? Interested in trophy . . 30 40 6 86 Reduces population 1 50 26 35 . . Matter of principle 1 50 17 23 1 14 None of "these (volunteered) . . 2 3 . . Table 15. Responses of the general public. bighorn sheep hunters. and Division of Wildlife (00\1) employees to the question: "Do you strongly approve. somewhat approve. somewhat disapprove, or strongly disapprove of the following methods for minimizing disease outbreaks among bighorn sheep in Colorado. Placing some bighorn sheep in captivity for disease research purposes. Increasing"habitat for bighorn sheep. even though it could be harmful to some habitat used for other wildlife. such as deer: " Allowing sport hunting of adult female bighorns to control the sheep population size in Colorado and reduce the incidence of disease outbreaks." Population S8q)led Random S8q)le Bighorn Sheep Hunters 00\1 Persomel Percent NUlber Percent NUlber Percent NUlber Responding Responding Responding Responding Responding Responding OK to use captive bighorns for research? Strongly approve 218 44 85 68 61 60 Somewhat approve 203 41 32 26 26 25 Somewhat disappr~ve 40 8 4 3 7 7 Strongly disapprove 36 7 2 2 4 4 0 2 2 4 4 No opinion 1 �156 Table 15 cont. Population Sampled Random Sample B ighom Sheep Hunters DOW Persomel Nunber Percent Nunber Percent Nunber Percent Responding Responding Responding Responding Responding Responding Increase bighom harms deer? habitat if Strongly approve 88 18 T7 62 43 42 Somewhat approve 198 40 31 25 34 33 Somewhat disapprove 146 29 7 6 10 10 Strongly disapprove 58 12 8 6 8 8 8 2 2 2 7 7 No opinion Population Sampled Random Sample DOW Persomel Bighorn Sheep Hunters Nunber Percent Nunber Percent Nl.II1ber Percent Responding Responding Responding Responding Responding Responding Allow ewe harvest to control disease? Strongly approve 88 18 73 58 63 62 Somewhat approve 196 39 28 22 22 22 Somewhat disapprove 99 20 16 13 12 12 Strongly disapprove 108 22 7 6 2 2 7 1 1 1 3 3 No opinion �157 Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~ _ Project No. W-153-R-4 Mammals Research Work Plan No. 2A Mountain Sheep Investigations Job No. 9 Quantity and Quality of Mountain Sheep Habitat with Regard to Minimum Viable Populations and Response of Mountain Sheep to Human Activity Period Covered: Author: July I, 1990 - June 30, 1991 D. F. Reed Abstract Increasing recreation in the recently designated Arkansas Headwaters Recreation_Area has resulted in a concern that increa$ed human activity might be detrimental to resident mountain sheep populations. Cooperative efforts have developed between the Bureau of Land Management (BLM) ,'the Colorado Division of Parks and Outdoor Recreation, and the Division of Wildlife (DOW). BLM became committed to evaluating bighorn sheep habitat. It was judged that a DOW ManagementjResearch joint effort could do the habitat evaluation in cooperation with BLM as well as test a habitat model and the effects of disturbance on bighorn sheep. A Research Proposal, "Impacts of human activity on mountain sheep distribution and abundance" was prepared and presented to BLM. Secondly, a Program Narrative (PN) was prepared. Thirdly, a Cooperative Agreement was signed between the BLM and DOW where BLM committed $30,000 to the work described in the PN for the Segment beginning 1 July 91 and potentially $30,000 each of 3 following years, for a total of $120,000. Contract work has been planned with the University of Colorado Colorado Springs Geography and Environmental Studies Department to map and evaluate potential mountain sheep habitats. This will be done by using existing geographic information systems (GIS), scanning in BLM IR photos, and inputing bighorn sheep distribution and habitat field data. ��159 QUANTITY AND QUALITY OF MOUNTAIN SHEEP HABITAT WITH REGARD TO MINIMUM VIABLE POPULATIONS AND RESPONSE OF MOUNTAIN SHEEP TO HUMAN ACTIVITY Dale F. Reed P. N. OBJECTIVE Evaluate the quantity and quality of mountain sheep habitat with regard to minimum viable populations and test the response of mountain sheep to human activity. SEGMENT OBJECTIVES 1. Prepare Research Proposal. 2. Prepare Program Narrative. 3. Complete Cooperative Agreement between BLM and DOY for joint funding. ACKNOWLEDGMENTS I thank co-principal investig~tors M. Y. Mi-Her. R. B. Gill, J. Vayhinger, and S. Ogilvie for their ideas and suppor t, Division personneL D. Finch, Y. Travnicek, and J. Backstrand were most helpful in establishing the study areas. Division personnel D. L. Schrupp and D. C. Lovell were most helpful for their ideas and in coordinating GIS. BLM personnel E. Brekke provided base-line information, digital elevation maps (DEMS) , IR photos, and important coordination; and T. R. Grette assisted with plant identification. T. P. Huber (University of Colorado, Colorado Springs) scanned in 1R photos and assisted in establishing habitat training sites or "ground truthing". DESCRIPTION OF AREA Two areas of the Arkansas River Canyon between Nathrop and Parkdale were included in the study: Area A - about 10 mi2 north of the Arkansas River from about 1.0 mi east of Texas Creek to 1.5 mi west of Parkdale, and Area B about 20 sq mi north and east of the Arkansas River from east of Nathrop to east of Salida. Areas A and B include approximately the lower half of Segment 4 and Segment 2, respectively, as delineated by BLM (Bureau of Land Management 1988:1-3). The areas include steep to very steep mountain slopes both north and east of the Arkansas River Canyon. Rock outcrops are mainly of igneous rock, intermingled with very shallow soils, terraces, and gravelly alluvia. The vegetation is typically Pinus-Juniperus Spp. and/or mountain shrub interspersed with graminoid and Cholla communities. �160 METHODS AND RESULTS Methods for evaluating both the quantity and quality of bighorn sheep habitat follows Smith et al. (in prep). Methods for testing the response of bighorn sheep to human activity as covered in the PN will need to be developed further. RESULTS AND DISCUSSION A Research Proposal and a Program Narrative were prepared. Agreement between BLM and DOW was completed. A Cooperative LITERATURE CITED Bureau of Land Management. 1988. Final Arkansas River Recreation Management Plan and Environmental Analysis. U.S. Dep. of Int. Smith, T. S., J. T. Flinders, and D. S. Winn. 19 A habitat evaluation procedure for Rocky Mountain bighorn sheep in the intermountain west. (in prep) prepar9~eoQ Dale F. Reed Wildlife Researcher �161 Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~_ Project No. W-153-R-4 Mammals Research Work Plan No. 3A Pronghorn Investigations Job No. 2 Habitat Selection and Population Performance of a Pioneering Pronghorn Population Period Covered: Author: July 1, 1990 - June 30, 1991 T. M. Pojar Abstract The distribution of the Middle Park pronghorn (Antilocapra americana) herd has been monitored ~ince January 1, 198.1. During this. time, the population has increased from 80 to approximately 280 aruma.Ls.. (summer 1991). Based on 546 relocations, the"area of the minimum convex polygon (Mep) was 936 km2 (361 mi2) for "the season of maximum dispersal, i.e. summer. During winter when the popUlation distribution is most compressed, the area of the MCP was 81 km2 (31 mi2) based on 745 relocation points of marked animals. The populations rate of increase ranged from 0.17 to 0.52 and averaged 0.35 over the 4 years of available data. Based on a regression of popUlation size and rate of increase, the K-value for the population is in the range of 400 to 625 animals. Pronghorn hunting was permitted in Mid~le Park" during the 1990 season for the first time since the season was closed statewide in 1899. Fifteen permits were issued (10 buck and 5 doe/fawn) with 13 of the 15 permittees participating in the hunt. Nine bucks and 4 does were harvested and 1 buck was found unretrieved." Horn le~gths of 10 bucks were measured and averaged 32.3 cm (12.7 in)·'and.ranged from '26.2 em (10.3 in) '"to' 36-.'6cm (14.4 in) (Sherwick Min, Pers. Comm.). ��163 HABITAT SELECTION AND POPULATION PERFORMANCE OF A PIONEERING PRONGHORN POPULATION Thomas M. Pojar P.N. OBJECTIVE Describe population dynamics and habitat use of a pioneering, expanding pronghorn population. .SEGMENT OBJECTIVES 1. Describe seasonal and annual distribution of the Middle Park pronghorn population. 2. Determine sample sizes of radio-collared animals and observations necessary to describe habitat preferences. 3. Monitor population dynamics of Middle Park pronghorn with: a. Ground counts to describe changes in population size. b. Ground counts to quantify population sex and age composition. . STUDY AREA The study area is described in Pojar (1988:183-184). For orientation of Middle Park in relation to the state of·Colorado see Figure 1. The approximate area of sagebrush steppe habitat in Middle Park is outlined in Figure 1. This is considered to be the potential area of distribution for pronghorn in Middle Park. METHODS AND MATERIALS Seasonal and Annual Distribution Tracking was done mostly from the ground to increase the probability of observing and identifying animals with numbered plastic collars. A fixed-wing aircraft was used if an animal could not be located after a reasonable effort from the ground. Legal descriptions of animal locations were recorded to the nearest quarter mile then converted to UTM (U.S. Army 1973) coordinates for computer processing. All radioed animals have been located biweekly· (with very few exceptions) since January 1, 1987. The program MCPAAL (Stwue NO) was used to calculate the area of the m~n~mum convex polygon and the 95% ellipse for summer and winter areas of habitation. The relocation points for May, June and July define the "summer" area and points for December, January and February define the "winter" area. Population Size and Structure .... Herd structure ·estimates are obcaf.ned in late summe r or early autumn by locating all radioed animals and·classifying all anima_ls that accompany them. The herd structure estimate that is used in population projections is the one with the largest sample size obtained in August or September. Classification �164 after October 1 is not used because the probability of mistaking early fawns for does increases. In all winters since this population has been monitored, they have wintered in essentially the same relatively limited area. At some time during the winter they are all in a single group, which makes it possible to locate the entire population and obtain a complete count. In addition, it is possible to count all mature bucks (age 1~5 years and older) and verify or correct the buck:doe ratio from the earlier herd structure estimates. The total population count and number of mature bucks counted during winter are used in population projections. Population projections are based on the following assumptions: 1. Winter counts represent the total population and the total number of mature bucks in Middle Park. 2. Late summer age ratio estimates represent "recruitment" into the population. 3. Annual survival of mature bucks and does and female fawns is 92.5%. 4. Annual survival of males in their first year (after weaning) is 50%. (This severe mortality on male fawns is arbitrary, however, it allows the number of mature males in subsequent years of match fairly well with winter counts.) RESULTS Seasonal and Annual Distribution The last deployment of radios in Middle Park was in December, 1988. Attrition of the radios and mortality of radioed animals have resulted in a steady decline in the number of working radios. From a maximum of 24 functional radios in December, 1988, that number has decreased to 17 as of June, 1991. There are very few of the numbered yellow plastic collars that were put on animals during the December, 1986, trapping operation still remaining on animals. Many of the numbered blue plastic collars installed in December 1988 are still providing relocation data. Since December, 1986, there have been 2,659 relocations of radioed and plastic collared pronghorn in Middle Park. The total number of plastic collar relocations is 868 and the total number of radio relocations is 1,791. The relocations in these data bases have been sorted by "winter" which includes the months of December, January and February, and "summer" which includes May, June and July (Table 1). Winter relocations define the critical area inhabited during the time the population distribution is most compressed. The area of habitation during summer represents the maximum dispersion of the population. For this population the wintering area relocations are located within the area circumscribed by the summer area relocations (Figures 2,3,4 and 5). The wintering area comprises 2.3% of the summer area for 1991 and 8.6% of the summer area for all years. In Alberta Canada, the northern most range for this species, Barrett (1982) suggests that wintering areas typically repr~sent about 8% of th~ summer range. �165 Table 1. Area of habitation for Middle Park pronghorn in square kilometers (divide by 2.59 to convert to square miles) for 2 estimators of area--minimum convex polygon (MCP) and 95% ellipse as calculated by the program MCPAAL (Stuwe ND}. WINTERz SUMMERl 95% 95% N3 Ellipse MCP Ellipse MCP N3 1991 Radios Plastic Collars 85 437 1128 131 19 33 29 799 1981 49 7 15 114 817 1329 180 19 35 Radios Plastic Collars 426 507 954 571 75 67 120 821 1131 174 38 71 BothS 546 936 996 745 81 71 Both4 All Years 1 Includes relocations from May, June and July. z Includes re·locations from December, January and February. 3 Total- number of relocations. 4 See Figures 2 and 3 fQr a graphic representation of these locations. S See Figures 4 and 5 for a graphic representation of these locations. Population Size and Structure Accurate counts of the total population size can be obtained during winter and herd structure estimates are obtained in late summer (Table 2). The annual changes in population size are used to calculate the rate of increase (Nz - Nl / N1) (Table 3) which is then regressed on population size to estimate the populations K-value (Figure 6) (Caughley 1977). The rate of increase for 1990-91 of 0.17 is well below the 4-year average of 0.35. For this reason, the regression predicting the K-value has a steeper negative slope than the regression from the previous year and predicts a K-value of 377 animals (Figure 6). This is probably an unrealistic regression because it projects the intrinsic growth rate (the Y-intercept) at 0.70 which is most likely well above what is biologically possible for·this species given the observed herd structure of this population. Since there are only 4 points upon which to base the regression, the best estimate of carrying capacity for the Middle Park pronghorn, at this point in time, is a range of between 400 and 625 animals. As more data points are available, the reliability of the projected K-value should increase. Hunting was permitted for pronghorn in Middle Park during the 1990 season for the first time since the season was closed statewide in 1899 (Hoover et. al 1959) . Fifteen permits were issued (10-buck and 5 doe/fawn) with 13 of ·the 15 permittees participating. Nine bucks and 4 does were harvested-with 1 confirmed buck wounding loss and 1 additional suspected buck wounding' loss or �166 poaching (Sherwick Min, Pers. Comm.). Therefore, a total of 11 bucks and 4 does were removed from the population during the hunt. Having been an unhunted population, it would be expected that the harvested animals would represent older age classes and that the males would have relatively large horns. Min (1990) measured the horns of the 9 harvested males and 1 unretrieved buck. Horn length ranged from 26.2 cm (10.3 in) to 36.6 cm (14.4 in) and averaged 32.3 cm (12.7 in). The Boone and Crockett scores for these 10 animals averaged 69.58 and ranged from 58.0 to 79~25. The highest score in Boone and Crockett records is 93 for an animal taken in Arizona. Colorado's highest scoring animal is from Weld county with a score of 914/8, The minimum score to be included in the Boone and Crockett record book is 82 (Nesbitt and Wright 1981). The population projection for late summer 1991 is presented in Table 4. The projection is based on the age ratio obtained in August, 1990, and the total count of the herd and the number of bucks obtained during the winter of 19901991. In this projection, it is assumed that the age ratio will be the same as in 1990--47 fawns:lOO does. This is a critical assumption and the observed ~ge ratio for 1991 will have a significant impact on this projection. Table 2. Herd structure of Middle Park pronghorn based on a sample obtained by locating radioed animals in late summer. POP. NO. 'X B:D F:D SAM'X OF .YEAR RATIO· SIZE RADIO RADIO RATIO PLE POP. 1986' 1987 1988 1989 1990 80 122 160 223 261 7 24 22 17 5.7 15.0 10.2 6.5 36 54 40 56 22 77 77 -32 50 47 47 63 108 161 148 59 52 68 72 66 , This year's data based on the sample of the population trapped 16 December 1986. Table 3. Population size of the Middle Park pronghorn herd during winter and the calculated rate of increase. YEAR POP. SIZE RATE OF INCREASE 1986-87 1987-88 1988-89 1989-90 1990-91 80 122 160 223 261 .52 .31 .39 .17 �167 Table 4. Population projection for the Middle Park pronghorn population. text for the assumptions. POPULATION BUCKS DOES FAWNS TOTAL 62 124 60 246 WINTER MORTALITY 62 X .075 - 5 MORT 124 X.075 - 9 MORT 30X.5-l5B 30X.075-2D 31 PRE-FAWNING 1991 62 - 5 57 MATURES + 15 YRLS TOTAL - 72 124 - 9 115 MATURES + 28 YRLS TOTAL - 143 MATURE 57 YRLS 15 TOTAL 72 MATURE 115 YRLS 28 TOTAL 143 See WINTER '90-91 LATE SUMMER 1991 215 @ 47F:lOOD 143 X .47 67 FAWNS 282 LITERATURE CITED Barrett, M. W. 1982. Ranges, habitat and mortality of pronghorns at the northern limits of their range. Ph.D. Thesis. University of Alberta, Edmonton, Alberta. 223pp. Caughley, G. 1977. NY. 234pp. Analysis of Vertebrate Populations. John Wiley ~ Sons, Hoover, R. L., C. E. Till, and S. Ogilvie. 1959. The Antelope of Colorado. Colorado Game and Fish Dep. Tech·. Bull. 4. 1l0pp. Min, S. 1990. Effects of female choice on male reproductive success in male pronghorn: 1990 field season report. Dep. Systematics & Ecology, University of Kansas, Lawre~ce. 5pp xerox. Nesbitt, W. H -. , and P. L. Wright. 1981. Records of North American big game. Eighth Edition. The Boone and Crockett Club, Alexandria, VA. 409pp. Pojar, T. M. 1988. Habitat selection and population performance of a pioneering pronghorn population. Colo. Div. Wildl. Res. Rep. July, 181-l92pp. Stuwe, M. (ND). MCPAAL micro-computer programs for the analysis of animal locations. Program Documentation. Cons. and Res. Center, National Zoological Park, Smithsonian Institution, Front Royal, Virginia, USA. 18 printout pages. U.S. Army. 1973. Technical Manual: Universal Transverse Mercator Grid. Headquarters, Dep. of the Army, Washington D.C. TM No. 5-241-8, 64 pp. ��169 Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~ _ Project No. W-lS3-R-4 Mammals Research Work Plan No. 3A Pronghorn Investigations Job No. 4 Statewide Pronghorn Management Guidelines Period Covered: Author: July 1, 1990 - June 30, 1991 T. M. Pojar Abstract Discussions were held with Division of Wildlife biologists and administrators to help identify prominent issues regarding pronghorn management in Colorado. Using these issues as a general guide, a questionnaire was designed to identify other issues as perceived by the general public, pronghorn hunters and Division of Wildlife employees. An Lndependent; coinpany ; Standage Accureach,. Inc., conducted. the survey and the results '.areavailable from the author or the Research Center Library in Fort Collins. A document titled Pronghorn Management Analysis Guide, 1992-1994 (third draft) is available from the auchor . This document outlines the history of pronghorn management in Colorado and provides an analysis of the management environment. The issues are examined in terms of the social, political, economic and biotic environment. Public meetings will be held to discuss currently identified issues and attempt to identify other issues that the public might raise. (_ ~ Prepared by ~~ . . omas M. POJa Wildlife Researcher oyw . ��171 Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~ _ Project No. W-1S3-R-4 Mammals Research Work Plan No. 6A Mountain Lion Investigations Job No. 1 Mountain Lion Population Dynamics Period Covered: Author: July 1, 1990 - June 30, 1991 A. E. Anderson Personnel: See Acknowledgments Abstract A'working outline for the CDOW Tech. B~ll. nThe puma (Felis concolor hippolestes) on Uncompahgre Plateau Colorado" by A. E. Anderson, D. C. Bowden, and D. M. Kattner is presented with percentages of each major section completed. Essentially, all the narrative is complete except for the RESULTS .AND DISCUSSION section (30%) and the SYNTHESIS AND CONCLUSIONS section (0%). ��173 MOUNTAIN LION POPULATION DYNAMICS Allen E. Anderson P. N. OBJECTIVE To assess the effects of sport hunting on mountain lion populations. SEGMENT OBJECTIVE To prepare final reports for publication. ACKNOWLEDGMENTS Most statistical analyses and computer graphics were performed by Dr. D. C. Bowden, Dept. Statistics, Colorado State University, Fort Collins. D. Masden, Inventory Biologist, Southwest Region, CDOY, assisted with mapping relative average densities" of·deer and elk on winter ranges of Game Management Units 61 and 62. N. McEwen produced or supervised CSU Graphics Dept. personnel prepare most of the figures for the puma publication. M. Roelke, D.V.M., and her colleagues from the Florida Panther Biomedical Investigation and the National Institute of Cancer kindly provided their information on the hematology genetics, spermatozoa, and drug immobilization of Uncompahgre Plateau puma. METHODS AND MATERIALS Between 16 April 1981 and 15 April 1988, 57 puma were captured and 49 were fitted with radio collars. I obtained 3,117 aerial locations of 38 surviving radio-collared puma on 349 fixed-wing flights totaling 1,081 hours (3."1 hours/flight). These locations, recorded as UTM coordinates, permitted calculation of indices of puma home range size, movement, intraspecific interactions and survival. General methodology is described in Anderson (1983). Additional information on some aspects of morphology and physiology came from opportunistic acquisition and necropsy of puma carcasses. RESULTS AND DISCUSSION The manuscript for CDOY Technical Publication, "The puma (Felis concolor hippolestes) on Uncompahgre Plateau, Colorado" by A. E. Anderson, D. C. Bowden, and D. M. Kattner was not completed because of severe arthritis coupled with the side effects of several new, mostly ineffectual prescription drugs for arthritis during the fall, winter, and early spring of 1990-91. Here, I present the outline of that manuscript with the estimated percentages of each section completed in handwritten form. This does not include the "final handwritten copy ready for typing. �174 Percent Complete INTRODUCTION 100 DESCRIPTION OF STUDY AREA AND VICINITY Physiography and Geology Climate Vegetation Livestock and Range Condition Timber Harvest Mammals and Birds Puma.-Mule deer.-Elk. -Pronghorn ante1ope.-Desert bighorn sheep.-Black bear.-Bobcat.-Coyote.-- 100 100 METHODS General Approach Capture and Drug Immobilization Processing Radio Telemetry Home Range Movements Intraspecific Interactions Interspecific Interactions Puma and wild prey.-Puma and 1ivestock.-Puma and humanso-Population Dynamics Sex and age structure.-Litter size.-Numbers and density.-Mortality.-Estimates of survival.-Morphological and Physiological Body mass and measurements.-Growth rateso-Indices of carcass fat.-Organ-gland masses and measurements.-Genetics.-Cellular and chemical constituents of b1ood.-Semen characteristics.-Parasites. diseases and injuries.-Population Dynamics Sex and age structure.-Litter size.-Calculation of numbers and density.-Morta1ity.-- RESULTS AND DISCUSSION Capture Drug Immobilization Aerial Telemetry Indices of Home Range Size. Indices of Movements Intraspecific Interactions �175 Percent Complete Interspecific Interactions Puma and wild prey.-Puma and livestock.-Puma and humans.-Morphological and Physiological Body mass and measurements.-Growth rates.-Indices of carcass fat.-Organ-gland masses and measurements.-Genetics.-Cellular and chemical constituents of blood.-Semen characteristics.-Parasites. diseases and injuries.-Population Dynamics Sex and age structures .--Litter size.-Numbers and density.-Mortali ty. -Estimates of survival.-Population model-potential harvest rates.--a o SYNTHESIS AND CONCLUSIONS LITERATURE CITED 80 _aTo be completed by Gary C. White, if he deems the_available data are relevant and adequate for that exercise. As previously stated, about 50 tables, 30 figures, and 7 appendices will be included. LITERATURE C.ITED Anderson, A. E. 1983. Program Narrative Proj. 45-01-503-15050, Work Plan 6, Job 1. Mountain lion population dynamics. 7pp. (+3 tables and 1 appendix) . Prepared by atLt;-t<) £_' {f_'1l iJ'/f''l.t T Allen E. Anderson Wildlife Researcher ¢;ti ) ��Colorado Division of Wildlife Wildlife Research Report July 1991 JOB PROGRESS REPORT State of ~C~o~l~o~r~a~d~o~ _ Project No. -W-lS3-R-4 Work Plan No. Mammals Research 8A Small Carnivorous Mammals Investigations Job No. Development of River Otter Reintroduction Procedures Period Covered: Author: July 1, 1990 - June 30, 1991 T. D. I. Beck Personnel: T. Benjamin, J. White, G. White Abstract .. . Three juvenile male river otters-(Lutra canadensis) were received· in good health from Oregon in 1990 for release into the Dolores River. At least 2 died prior to spring, and the fate of the third is unknown. Radio telemetry on the animals released in 1989 has been limited because of technical deficiencies in equipment. Limited results from the 3 otters this year suggest telemetry problems may be solved. Dispersion of river otters is widespread throughout the Dolores and San Miguel Rivers. Survival of reintroduced juvenile river otters seems. to be less than for adults. A third population estimation procedure was tested for estimating crayfish (Orconectes virilis) density. Number captured indicate a minimum density of 6.4 adults/m2• Estimation procedure analyses have not been completed. Sightings of river otter at previous release sites suggest the reintroductions have been successful in the short-term and dispersal is occurring. ��179 DEVELOPMENT OF RIVER OTTER REINTRODUCTION PROCEDURES Thomas D. I. Beck P. N. OBJECTIVE Develop procedures for river otter reintroductions in Colorado and establish a self-sustaining population of river otters from which to collect river otters for future translocations. SEGMENT OBJECTIVES 1. Introduce up to 10 river otters-into the Dolores River drainage. 2. Develop techniques to monitor survival, reproduction, dispersion, and dispersal of river otters after introduction. 3. Monitor other river otter release sites in Colorado to evaluate success of past reintroductions. METHODS AND MATERIALS Dolores River Release River otters were captured ~hroughout Oregon by personnel of the-Or~gon Dept. of-Fish & Wildlife under the direction of Meg Eden. The cage-type trap' developed by-Oregon staff was used. River otters were shipped in_transpor.t cages (41 X 41 X 76 cm) via commercial airline to Durango, Colorado. Animals were shipped at 0700 (PDT) and arrived in Durango at 1630 (MDT). River otters were transported to Dolores and released in holding pens (2.6 X 5.2 m) with running water. Food (crayfish and suckers) was provided. All prototype radio transmitters from AVM Equipment Co. were reconstructed to provide greater power to the transmitter in order to increase range from subterranean beaver dens. The larger battery resulted in a slightly heavier and longer trarismitter package; the unit weighs 26 gms and is 70 mm long with a diameter of 17 mm. The 185 mm long whip antenna has an epoxy bead on the distal point to provide a blunt surface. The desired specifications for the upgraded radio transmitter required reception at 300 m when the transmitter was buried in wet soil to a depth of 20 cm and-battery life of 24 months. River otters were removed ~rom the holding pens and transported to Cortez Veterinary Clinic for surgical implantation of the radio transmitters on the morning following their arrival. The river otters were transferred to a squeeze box at the clinic, where immobilization was obtained from intramuscular injection of ketamine (100 mg/ml) and xylazine (20 mg/ml) at a dose rate of 15 mg ketamine per kg of animal. A paste made from betadine and petroleum jelly was thoroughly massaged into the incision areas. This allowed the hair to be combed away from the incision line, omitting the need to shave the area. Two incisions were made along the dorsal mid-line. The larger (2-3 cm) was made at a point between the shoulders while the smaller (1 cm) was made 190 mm posterior to the first. A pocket large enough to hold the -t-ransmitte-r was made under the skin at the anterior LncLsLcn , Blunt sponge -forceps were used to push under the skin from the posterior to anterior incision. The transmitter antenna was pulled under the skin from the anterior �180 incision. Both incisions were closed with subcuticular sutures and Super Glue. Each river otter was tagged with a Monel #3 metal tag in the web between front toes and was measured for total length; tail length; neck, chest, and head girth; and weight. All injuries were recorded. Fecal parasites, white blood cell count, and hematocrit were analyzed. River otters were placed in transport boxes in a cool room until recovered from anesthesia. They were transported to the Dolores River for release. Radio tracking was conducted on foot, by canoe, and from the air. All locations were recorded to the nearest 0.1 mi. Two aerial searches .of the San Miguel, Dolores, and Colorado Rivers downstream to Lake Powell were conducted after coordination with Utah Div. of Wildlife Resources. Crayfish Studies A 5-day mark-recapture study was conducted at RM 151.3 during late July. Baited wire crayfish traps were set in a 5 X 5 grid equally spaced throughout an area 21-m square (the width of the river). A pe1leted, commercially available bait was used with a standard amount in each trap. Traps were checked once daily for 4 days. Each captured crayfish was uniquely marked by writing a number on the carapace with an ultra fine point Sharpie permanent marker. The carapace length, sex, identification number, trap location, and day were recorded for each capture. Marked crayfish were released at the site of capture prior to returning the baited trap to the river. Data were stored in a dBase file and forwarded to Gary White, Colorado State University, for analyses of population estimates and possible bias. Release Site Monitoring .. A.standardized river otter-sighting-form was developed and distributed- to District Wildlife Managers in areas of river otter release. All reported sightings are stored by river drainage. An l8=km stretch of the Piedra River was surveyed by canoe during low water (July) to search for river otter sign. The selected area was chosen because of consistent reports by fishermen of river otter presence. Periodic contact with Utah Division of Wildlife Resources personnel was continued to monitor movement of radio-transmittered river otters in the Green River along the state borders. Contacts were made with commercial boating companies and BLM river rangers to obtain river otter sightings in the Colorado River in the Utah-Colorado border area. RESULTS AND DISCUSSION Dolores River Release Four male river·otters were received from Oregon. Three juveniles were received in good health in late October and early November (Table 1). All animals ate promptly upon release in pens. Recapture the following mo~ing was accomplished by leaving the transport boxes in the pen for a den, with the sliding door in the up position. By quietly entering the pen at first light, the door was closed with the unstressed animal within. The modified surgical procedure which omitted shaving of hair appeared to work well although more time was needed to close the incision cleanly. �l8l Table 1. River otters released in the Dolores River, CO, 1990. Length (cm) Iotal IaU ~lI~YmfeIence (cm) Che§t H~ad He~k III S~X Yt(kg) RO-35 M 3.9 95 35 23.0 21.5 32.5 35 Tenmile Lake, OR RO-36 M 5.2 106 41 24.5 25.0 34.5 36 Tenmile Lake, OR RO-37 -M 6.0 106 44 24.5 26.0 34.5 37 Yillamette Slough, OR lag ~ Qrigin An adult was dead on arrival. He had chewed a large hole through the metal trap upon capture and was considerably stressed. A necropsy indicated massive hemorrhaging in the lungs but no metal scraps in the gastrointestinal or pulmonary tracts. One juvenile male was found dead along the shoreline 3 km upstream from the release site 2 weeks following release. A necropsy indicated an absence of subcutaneous and mesenteric fat with accompanying signs of severe emaciation. The stomach and intestines were empty. As no other wounds were discovered, starvation was considered the likely cause of death. Another juvenile male remained in an abandoned beaver den near the release site. The river iced over the first week of December. Fresh river otter scat was regularly observed near the den area throughout December. This male also died during the winter. The decomposed body was discovered at the entrance to the beaver den in 0.7 m of water after ice break up in the spring. The third juvenile male- expelle-d the radio transmitter in a beaver den _soon after release. Fresh rive~ otter scat, tracks, prey:remairts, and 2 sightirigs indicated a river otter used the beaver den regularly through December and January. The transmitter was recovered at a depth of 1.7 m and 16 m from the shoreline. The improved radio transmitters did allow for location when river otters wer·e in subterranean beaver dens although the short periods of tracking provided limited data. ~adio transmission exceeded 300 m at all times, even when the transmitter was. deep within a beaver den. The initial prototype radio transmitter performed inadequately to allow consistent monitoring of river otter movements. If the animal was on shore or swimming, the transmitters could be detected at distances of 250-400 m. Ho~ever. once the river otter entered a beaver den, reception usually went to zero and rarely exceeded 30 m. An adult male (RO-4) from the November, 1988, release was located in the San Miguel River near the mouth of Horsefly Creek in August, 1990, 43 river miles upstream from the Dolores River confluence. This site is 124 river miles from the release site. He had not been located since April, 1989, until this time. Other river otters from the 1988 release were last located within the Dolores River. Cessation of radio transmission on all was likely normal battery exhaustion. RO-l, an adult male, was last located at RM 130 in May 1990. He had been remaining between RM 130 and 140 during March, April, and May. RO-7, an adult male, was-found in McPhee Reservoir through most of the-summer of 1990 and was last located in September at RM 170, about 12 miles downstream of the dam. An adult male, RO-3, and an adult female, RO-5, were last located in December, 1989, using the area between RM 165 and 170. �182 Location of the river otters released in 1989 remains largely unknown because of poor equipment performance. Two transmitters were recovered from beaver dens after being expelled from the animal, likely because of suture failure. An adult female, RO-2s, was recovered dead at RM 107 on 26 July 1990. She was lying on a sandbar where we camped 3 weeks previous. Her whereabouts between release at RM 146 on 9/12/89 and death are unknown. An adult female, RO-26, moved downstream into the Colorado River where she was located several times in August and September, 1990, in the Castle Creek area about 10 miles downstream of the Dewey Bridge (Utah). Distance moved was at least 158 miles since release on 10/5/89. Personnel of Utah Div. Wildlife Resources were notified of her location and we ceased monitoring in September, 1990. Two juvenile females, RO-27 and 28, died within 2 weeks of release within 2 miles of the release site. An adult female, RO-31, was located at the confluence of the San Miguel and Dolores River,-RM 64.5, in September, 1990. She had been at RM 135 in late March. RO-32, an adult male, left the river and was found dead 6 miles from the river. Another transmitter, from adult male RO-12, was located in a draw amidst wheat fields approximately 4 miles from the Dolores River. Transmission was weak at the time (July 1990). By the time permission was obtained to trespass, no signal was received and aerial searches have not located the transmitter. An unmarked, nursing female was killed in a conibear trap set for beaver on 10 June, 1991, about 5 miles above the town of Dolores. No young were found after 1 day of ground searching. The source of this animal is unknown, but she may be the offspring of-RO-S. Although presence of young was never confirmed for RO-S in 1989, her restricted movement in April and May, 1989, suggested she may have young. The strong affinity for large subterranean beaver-~ens ~imited_our success at visual sightings. Although RO-s moved -about ls--miles upstream in late summer, such a move would- not be difficult for jUvenile river ~tters at this time. Juvenile river otter received from Oregon in early September have ranged from 90 to 105 -cm in total length. A dead juvenile river otter was recovered from the Piedra River on 6/30/91 and had a total length of 49 cm. _Although quite limited, it appears that juveniles have attained nearly SOX of their adult length by 1 July. This suggests that accurate identification of juvenile age status will become increasingly difficult after 1 July. The loss of released animals to death and dispersal further suggests the need to release a lot of animals in each release site. The relatively poor survival of juvenile river otters after translocation suggests this age group should be avoided for reintroductions. Another 10 river otters are anticipated for release in 1991. With the apparently improved radio transmitter, prospects of learning" appear to be better in 1991-92. Crayfish Studies Total crayfish marked during the 4 capture periods was 3,101. Over 800 individuals were recaptured and only 2 individuals had unreadable markings. Both of these were initially marked on day 1 and recaptured on day 4. Analyses of the data are not completed. Complete reporting and discussion of the 3 crayfish population estimation tests (removal, unique mark for day of capture only, unique numbered individual) will be completed in the coming .segment. Using the same capture procedure at 3 sites for the 3·tests has produced 4-day capture totals of 1,390, 2,470, and 3,101. Minimal densities of adult . crayfish based on captures range from 2.7 to 6.4/m2. Since captures likely do �183 not represent the total population density can be presumed to be higher. A density of 6.4/m2 provides a standing stock biomass of crayfish of 1,012 kg/ha (903lb/ac) (avg. adult crayfish - 15.75 gms, n - 2,470). Crayfish provide an abundant food source for river otters in the Dolores River. There is reason to believe that crayfish numbers are increasing in the lower canyon where crayfish were rare in 1988. The relative abundance survey conducted from RM 173 to RM 74 will be repeated in 1991. An observation of a river otter foraging at RM IlIon 8 December 1990 was enlightening. This stretch of river had few crayfish present in 1988, yet the river otter was successful at catching a crayfish on each of 21 consecutive dives during an hour period during a season when crayfish are inactive. Release Site Monitoring Observations by outdoorsmen strongly indicate that river otters are present in Navajo Reservoir and all the major tributaries of this large reservoir. While the majority of sightings occur in the reservoir and the Piedra River, reputable sightings also come from the San Juan, Navajo, and Pine Rivers. River otters are consistently sighted throughout the Piedra River drainage and the small tributaries. At least 3 river otters released in the Green River in Utah have ventured into Colorado, traveling in both the Green and Yampa Rivers. Since only a small pr'oportion of the animals released in Utah were radio transmitter equipped, there could be others. It appears likely that continued releases in Utah will result in some river otters taking permanent .residence in .Colorado'.sportion '.o-f'the Green River. Sightings of river otter are consistently made on the Colorado River between Westwater Ranger Station and Dewey Bridge in Utah. The regularity of sightings is probably a response to the high recreational use of this river segment. While at least 1 river otter from the Dolores release has joined this population, the appearance of this population predates the initial Dolores release. It is speculated that this population is the result of dispersal from either or both the North Fork Colorado River or the Gunnison River releases. There was a reputable sighting of a river otter in the White River during 1990. Either overland travel from the Colorado River or a long dispersal from the Green River are possible sources for this animal. By .---.L~· -"",=~....;...;;....;j)J:;.;;......_~___;;;;;;~_ Thomas D. I. Beck Wildlife Researcher ��185 Colorado Division of Wildlife Wildli~e Research Report July 1991 JOB PROGRESS REPORT State of Colorado Project No. W-lS3-R-4 Work Plan No. 9A job No. 1 Mammals Research Elk Investigations Impact of Elk Winter Grazing on Livestock Production and Work Plan No. 3 Job No. S Period Covered: Author: July 1, 1990 - June 30, 1991 N. T. Hobbs, D. L. Baker, and G. Bear Personnel: D. Bowden Abstract We continued analysis of cattle weight responses. Calf weights taken at the end of the spring grazing season showed weak effects of treatment (30 elkfkm2 vs. control, ~ - 0.091) when effects of calf weights into the pasture were removed. using covariance. Analysis of covariance was needed to increase precision in the analysis and to remove significant tendency for calf weigh,ts i:qtothe pasture to be heaviest in the contrro Ls . This cendency was not rela.'tedto treatment and resulted froJ;ll random assignment of replacement animals. Calf weights in fall were also weakly ·influenced by elk grazing (linear effects ~ - 0.09). Cow weight performance was not affected by elk grazing. a ��187 IMPACTS OF WINTER GRAZING BY ELK ON CATTLE PRODUCTION P. N. OBJECTIVES 1. To test the hypothesis that elk grazing during winter influences the productivity and botanical composition of herbage on sagebrush grassland ranges during spring. 2. To test the hypothesis that elk grazing during winter influences the body weights and rates of gain of cows and calves using sagebrush grassland ranges during spring. METHODS AND MATERIALS Study Area We conducted experiments on the Little Snake Wildlife Management Area in northwestern Colorado (township 9 north, range 95 west, sections 9, 10). The area is about 35 km (19 mi) north of Maybell, Colorado, on County Road 19. Although this area does not typically contain high concentrations of elk during winter, it is representative of areas that do have those high densities. Topography of the area includes level ridge tops, rolling hills, and deep gullies, ranging in elevation from 1800 to'2000 m (5900 to 6600 ft). Aspects are southern and southwesterly with'an, average slope of 15 degrees. Soils care generai.lY sandy and sandy loam .. Climate of the area is dry and cold. The growing season averages only 81 days. Annual mean temperature is 6.06 C (42.9 F). Annual precipitation averages 27.5 cm (12.5 in). Vegetation is dominated by big sagebrush (Artemisia tridentata) with 'an understory predominated by needle and thread (Stipa comata). western wheatgrass (Agropyron smithii), Indian ricegrass (Oryzopis hymenoides), Junegrass (Koleria cristata), and cheatgrass (Bromus tectorum). Important forbs include wallflower (Erysimum asperum), peppergrass (Lepidium perfoliatum), silver lupine (Lupinus argenteus), and, scarlet globe mallow (Sphaeralcea coccinea). Experimental Design We observed effects of elk grazing on forage and cattle responses in a randomized'comp1ete block design with 4 levels of elk density (0 elkjkm2, 8 e1kfkm2, 15 e1kfkm2, and 31 elkjkm2) and 3 replications per level. There were 3 blocks, each consisting of 4 pastures. Each pasture within a block was stocked with one level of elk density such that each block contained all levels. During year 1, the 12 available pastures were blocked by pretreatment biomass of perennial grasses with the 4 lowest grass biomass pastures forming I block, and the 4 highest grass biomass pastures forming a second block, and the remaining 4 pastures serving as the third block. The 4 levels of elk density were randomly assigned ,to pastures within each block during year 1. Procedures We stocked pastures with elk in December and January, 1987-89. Average date of release int:opastu~es.was Jan~ry~. All elk were removed from pastures during April 10-20. We introduced 7 cow-calf pairs and one dry heifer into each pasture on May 9; 1990, and removed them 5 weeks later. This represents a departure from the first 2 study years when animals remained in the pastures for 6 weeks. �.... ,.,., .. "'.. ,~"..... , .... ,...•.•••••.• " ,.•""u~. 188 However, a marked reduction in forage production during the 1988-1989 growing seasons compelled us to reduce the stocking rate during 1990 in order to preserve consistent utilization rates in control pastures. With the exception of addition of new heifers and other replacements required by death losses etc., cows during year 4 were the same animals we observed during year 3 and were assigned to the same pastures they were in previously. We observed the birth dates of all calves and weighed them to the nearest 0.05 kg immediately after birth. Cows and calves were weighed to the nearest 1 kg when they were introduced to pastures and were reweighed 5 weeks later when they were removed. We estimated canopy cover of herbs shrubs immediately after removing cattle from pastures. Cover was estimated from the summed length of interception by each plant along 30, l2-m transects randomly placed in each pasture during year 1. We estimated standing crop, productivity, and utilization of forbs, perennial grass, and annual grasses by harvesting samples from 40 pairs of 0.70-m2 plots in each pasture on each of 3 sample dates. Pastures were sampled immediately after the elk were removed (April 27-29), at the midpoint of the spring grazing season (May 30-J'une 1), and at its end (June 30-July 2). Samples were dried at 60 C for 48 hrs, separated by hand into live and dead, and weighed to the nearest 0.01 g. We used an analysis of covariance for a randomized complete block design to analyze weight responses of cattle. Calf weight into the pasture was used as a conco~itant observation for calf weights out of pastures and for rates of gain. Cow weights into the.pastures were used similariy for adult cattle and .heifers. We are in·the process of consUlting with Dave Bowden (Statistics Department, Colorado State University) on the details of. this analysis to assure our statistical approach is reliable. Future analyses will reflect these consultations, and may offer somewhat different results than we report here. RESULTS AND DISCUSSION Averaged across the 4 study years, elk grazing during winter and early spring caused small reductions in calf performance during spring on sagebrush grassland range (Fig. 1). These reductions were shown in statistically weak effects on calf weights at the end of the spring grazing season (control vs. 30 elkfkm2, ~ - 0.091, linear effect ~ - 0.11, Appendix Table 1) and·in the fall (control vs 30 elkfkm2, ~ - 0.12, linear effect ~ - 0.11, Appendix Table 2). Calf Weights at Weaning Covariate-Calf Weight Into Pasture Calf Weights out of Pasture Covariate-Calf Weight Into Pasture 130 270 120 250 ~ 110 --;; 100 ~230 --;; 210 o ~ 90 ~ ~ 80 70 1/1 .. 60 ~ 50 ~ 190 ] 170 I---..1 I -tI----~·TI----------__J~ ~ 10 20 Elk Oensity (animols/km2) 30 I ~ 150 ~ 130 ~ 110 40 o I--____~I_-'+l------tI 40 90 70~ -r o ~ 10 20 ~ 30 --r 40 Elk Density (animols/km2) Fisure 1. Effects of elk srazins on calf ~eishts at the end of the sprins srazing season and in the fall averased over 4 study years. Means adjusted to common weight into pasture. Vertical bars - ! 2 standard errors of the mean. �·r.o·" ...•.•_.,., .... ,',.' ..•..•~:,_•.•'~.'.'.'.:.', ' •..••. ", .•.•• ":' ..• .'.: ..' •... ,'., ', ,',_". , ...•. , ... . "< ., ....•.•. 189 Although there appeared to be a statistically significant effect of treatment on the covariate (linear effect ~ - 0.02, Appendix Table 3), this appearance was created by effects of initial randomization and replacement of cattle· over the 4 study years. Weights of animals taken into the pasture in the animal's first study year tended to be heaviest in the control pastures (linear effect ~ - 0.13. level effect - 0.10, Appendix Table 4). It is clear that there was no opportunity for treatment to influence these weights, since these animals were not in the experiment the previous year. Consequently, it was important to remove the effect of weight into the pasture from the analysis of weight out of the pasture to remove this spurious influence. Effects of elk grazing on cow weights were less strong than effects on calf weights (Fig. 2). Cow weights at the end of the spring grazing season were not influenced by treatment (level effect ~ - 0.53, Appendix Table 5), nor were weights in the fall (level effect ~ - 0.81 Appendix Table 6). Cow Weights at Weaning Covariate-Cow Weight Into Pasture Cow Weights Out of Pasture Covariate-Cow Weight Into Posture soo 700 'Clsoo 'Clsoo Co c ~400 Co I e I I I '":! ~ 500 ..., I :! ~300 I I I ~400 -.. -.. III III ~300 ~200 ..J 100 200 0 . 10 20 30 40· 0 "0 20 30 Elk Density (animols/km2) Elk Density (animols/km2) Fi&ure 2. Effects of elk &raziD&on cow wei&hts at the end of the sprins &razins season and in the fall averqed over 4 study years. Meena adjusted to coamon wei&ht into pasture •. Vertical bars - :t 2 standard errors of the .ean. AJ! Prepared by JI. ~~~~~~~ __,~~~-------N. Thomp~obbs Wildlife Researcher Dan L. Baker Wildlife Researcher &-:;9.~ George D. Bear ,!ildlife.R~searcher 40 �190 APPENDIX Table 1. Analysis of effects of elk grazing on calf weights out of the pasture. Weight into the pasture used as a covariate. Source DF Sum of Squares F Value Pr > F Model 27 70258.8345613 Error 269 8677.1499520 Corrected Total 296 78935.9845133 R-5quare C.V. 0.890074 7.317328 Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Source LEVEL 80.67 0.0001 CALFWT3 Mean 77.61754376 DF Type III SS F Value 3 653.84565390 1.83 Pr > F 0.2429 Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Contrast linear in level > DF Contrast S5 F Value 1 411.35624562 3.45 0.1128 Pr F_. Tests of Hypotheses using the Type III MS for LEVEL*BLOCK .as an error term Contrast control vs others DF Contrast SS F Value Pr > F 1 150.47337906 1.26 0.3045 Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Contrast control vs 30 DF Contrast S5 F Value Pr > F 1 479.59535164 4.02 0.0919 �191 Table 2. Analysis of effects of elk grazing on calf weights at weaning. Weight into the pasture used as a covariate. Source DF Sum of Squares F Value Pr > F 8.91 0.0001 Model 27 90144.7329757 Error 194 72660.5311826 Corrected Total 221 162805.2641582 R-Square C.V. CALFWT4 Mean 0.553697 10.26008 188.62436648 Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Source LEVEL DF Type III SS F Value Pr > F 3 1905.21474849 1.56 0.2948 Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Contrast linear in level DF Contrast SS 1 1642~36756617 F Value· 4.02 Pr > F 0.0917 Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Contrast control vs others DF Contrast SS F Value Pr > F 1 355.89964895 0.87 0.3865 Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Contrast control vs 30 DF Contrast SS F Value Pr > F 1 1347.22823490 3.30 0.1192 \" �192 Table 3. Analysis of effects of elk grazing on calf weights into the pasture. Source DF Sum of Sguares F Value Pr > F Model 23 2911.23904230 Error 282 31535.07620304 Corrected Total 305 34446.31524534 1.13 0.3097 R-Square C.V. CALFWT2 Mean 0.084515 20.50860 51. 56277357 Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Source DF Type III 55 F Value Pr > F LEVEL 3 911.82076041 3.30 0.0993 Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Contrast linear in level DF Contrast·5S F Value Pr > F 1 788.27400753 8.56 0.0264 Tests of Hypotheses using the Type III M5 for LEVEL*BLOCK as an error term Contrast control vs othe.rs DF Contrast 5S F Value Pr > F 1 681.64425126 7.41 0.0346 Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Contrast control vs 30 DF Contrast S5 F Value Pr > F 1 902.62088763 9.81 0.0203 �193 Table 4. Analysis of level effects on calf weights into of the pasture for animals that had not been exposed to treatment during the previous year. Dependent Variable: CALFWT2 Calf Wt. into Pasture (kg> Source DF Sum of Squares F Value Pr > F Model 23 2582.60168367 1.03 0.4327 Error 111 12072.78073069 Corrected Total 134 14655.38241435 R-Square C.V. CALFWT2 Mean 0.176222 20.95520 49.76802617 Tests of Hypoth~ses using the Type III MS for LEVEL*BLOCK as an error term Source LEVEL DF Type III SS F Value Pr > F 3 320.17215152 2.98 0.1183 Tests of Hypotheses using th~ Type III MS for LEVEL*BLOCK as an error term Contrast linear in level DF 1 Contrast SS F Value Pr > F 108.66582810 3.03 0.1322 Tests of Hypotheses using the Type III KS for LEVEL*BLOCK as .an error term Contrast control vs others DF 1 ss F Value Pr > F 26.31300408 0.73 0.4243 F Value Pr > F 3.52 0.1098 Contrast Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error termContrast control vs 30 DF 1 Contrast SS 125.98786452 �194 Table 5. Analysis of treatment effects on cow weights out of the pasture. Weight into the pasture used as a covariate. Source DF Sum of Squares F Value Pr > F 259.20 0.0001 Model 27 2506670.67384 Error 321 114976.27262 Corrected Total 348 2621646.94646 R-Square -C.V. COWWT3 Mean 0.956143 4.611057 410.44136229 Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Source LEVEL DF Type III SS F Value Pr > F 3 10098.2755001 0.82 0.5280 Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Contrast linear in level DF Contrast SS F Value Pr > F 1 7688.19114~03 1.88 0.2199 Te_sts of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Contrast control vs others DF Contrast SS F Value Pr > F 1 5297.15925425 1.29 0.2990 Pr > F Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Contrast control vs 30 DF Contrast SS F Value 1 9345.20106116 2.28 0.1'818 �195 Table 6. Analysis of level effects on calf weights out of the pasture. into the pasture used as a covariate. Dependent Variable: COWWT4 Cow Wt. in Nov. (kg) Source DF Sum of Squares F Value Pr > F Model 27 1387620.27444 76.55 0.0001 Error 295 198063.05616 Corrected Total 322 1585683.33060 R-Square C.V. COWWT4 Mean 0.875093 5.630769 460.17495866 . Dependent Variable: COWWT4 Cow Wt. in Nov. (kg) Tests of Hypotheses using the Type III MS for LEVEL*BLOCK. as an error term Source LEVEL DF Type III SS F Value Pr > F 3 1827.83167023 1.26 0.3704 Contrast 55 F Value Pr > F 31.43407666 0.06 0.8076 Tests of Hypotheses using the Type III MS for LEV.EL*BLOCK as an error term Contrast linear in level DF 1 Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Contrast control vs others DF Contrast 5S F Value Pr > F 1 1149.45664340 2.37 0.1748 Contrast 55 F Value Pr > F 162.37424777 0.33 0.5841 Tests of Hypotheses using the Type III MS for LEVEL*BLOCK as an error term Contrast control vs 30 DF 1 Weight � https://cpw.cvlcollections.org/files/original/d8e3d34335d9f1fbe05e530e5782cb36.pdf e43924251705d46137dd522c25f6e5e7 PDF Text Text 1 Colorado Division of Wildlife Wildlife Research Report October 1991 JOB FINAL REPORT State of _......:::C~o~l~o~r~a~d~o:..._ _ Project Work Plan Avian Research - Migratory Game Birds W-152-R-4 _1_ Job 17 Job Title: Habitat use by wintering mallards near the Front Range of Colorado Period Covered: Author: 1 April 1990 through 31 March 1991 James K. Ringelman Personnel: R. Falise, Colorado State University; L. Roberts, Front Range Land and Cattle Company. ABSTRACT All data from this project have been collected and partially analyzed. Analyses continued early in this segment, but were later temporarily suspended while the principal investigators explored the feasibility of using a Geographical Information System (GIS) as a more desirable tool for data analysis and reduction. Training on appropriate GIS systems will take place next segment, with data analysis and manuscript preparation scheduled for completion next segment. Final analyses and publication preparation will be conducted under Work Plan 22, Job 2, Migratory Game Bird Publications. Prepared by: James K. Ringelman Wildlife Researcher C ��3 Colorado Division Wildlife Research September 1991 of Wildlife Report JOB FINAL REPORT State of __~C~o~l~o~r~a~d~o~ Project 1__ : Job Job Title: Winter Author: Avian Research W-152-R-4 Work Plan Period _ Covered: Clint W. Jeske, Game Birds 18 Survival 1 April - Migratory and reproductive 1990 through success 31 March James K. Ringelman of female mallards 1991 and Michael R. Szymczak Personnel: J. Ringelman, M. Szymczak, Colorado Division of Wildlife; G. White and B. Wunder, Colorado State University; D Anderson, J. Armstrong, J. Boulanger, K. Frye, M. Gilbert, D. Gilbert, Colorado Cooperative Wildlife Research Unit; M. Nail and R. Schnaderbeck, U.S. Fish and Wildlife Service, Monte Vista National Wildlife Refuge. ABSTRACT Mallards (Anas platyrhynchos) wintering in the San Luis Valley, Colorado were trapped and banded on the Monte Vista National Wildlife Refuge from December through March 1986-87,1987-88, and 1988-89. Body mass and a condition index for each bird were recorded to compare mass and condition among the age-sex classes; to identify :trends in.body mass through the winter; and to compare consistency of condition, relative to the population, of birds captured in subsequent years. Generally, .adults lla.,rl greater mass than Lmmatiuxe birds, and males had greater mass than .f'ema Les. .Females tended .to be in .be t ce r condition than males., and adults in better condition than immatures. Birds recaptured 'Lri subsequent years tended to be in similar relative condition classes. The low body masses recorded for mallards in the San Luis Valley may reflect responses to local environmental conditions (high elevation, predictable food resources, and avian predation) rather than poor nutrition. Carcass searches were conducted on the Monte Vista National Wildlife Refuge from January through April 1988 and January through April 1989. In 1988 and 1989, we recovered 4,604 and 1,738 carcasses, respectively. Avian cholera, which was a minor source of mortality in 1989, was prevalent in 1988. The sex ratio of carcasses recovered differed from the sex ratio of the population determined from aerial photographs in 1988 (X2 ~ 80.8, f < 0.0001), but not in 1989 (X2 ~ 0.3386, f - 0.5607). Starvation, determined from lipids in the ulna, was more prevalent among mallards which had been banded than unmarked birds. Logistic regression was used to determine relations of condition at time of banding and ��5 INTRODUCTION This final report is written primarily in dissertation format. The dissertation is composed of chapters that will be submitted for publication. All future work on this job by project personnel will be covered under Work Plan 22, Job 2 - Migratory Bird Publications. CHAPTER 1 BODY MASS AND CONDITION OF MALLARDS WINTERING IN THE SAN LUIS VALLEY, COLORADO Evans and Smith (1975) defined condition as "a measure of the chances of survival of an individual at a particular time of year, and/or of its potential for breeding successfully." Condition can be quantified by comparing body reserves of biologically important compounds, such as lipid and protein, in relation to environmental demands at any particular time. For waterfowl, body mass is often used in conjunction with external measurements to estimate lipid reserves and calculate a condition index (Bailey 1979, Chappell and Titman 1983, Gauthier and Bedard 1985, Ringelman and Szymczak 1985). These condition indices are then used to quantify changes in condition. Several important events (e.g., prebasic molt and pairing) occur during winter for migratory waterfowl (Heitmeyer 1985). Studies of cross-seasonal interactions among body condition and timing of biological events suggest body condition and hunting mortality are related (Bain 1980, Greenwood et al. 1986, Hepp et al. 1986, Reinecke and Schaiffer 1988), as are body mass and annual survival rate estimates (Haramis et al. 1986). Hepp (1986) found body mass and age to be related to time of pairing in American black ducks (~ rubripes). Pattenden and Boag (1989) found pairing and l~ying date to be related to winter body mass for captive mallards (~ p1atyrhynchos), but no relation between clutch size and body mass was found. Because body reserves used in waterfowl reproduction often accumulate before arrival on the breeding grounds (Heitmeyer and Fredrickson 1981), numerous studies have documented when and where reserves are accumulated (i.e., Krapu 1981, Heitmeyer 1985, Delnicki and Reinecke 1986, Hohman et al. 1988, laGrange and Dinsmore 1988). Here, we report on variations of body mass and condition for a semi-resident mallard population wintering under severe environmental conditions. Our objectives were to (1) identify trends in body mass and condition indices of marked birds from January through March; (2) compare body mass and condition of marked and unmarked mallards within and between winters; and (3) identify environmental components that may influence condition dynamics. STUDY AREA This study was conducted in the San Luis Valley (SLV), Colorado. The SLV is a l2,960-km~ intermountain basin in south-central Colorado, bounded by the San Juan Mountains to the west and the Sangre de Cristo Mountains to the east. Soils within the SLV are primarily fine sandy clay with little humus (Fenneman 1931). As a result of the surrounding mountains and a valley �6 elevation of 2,286 to 2,438 m, the SLV has an arid climate characterized by short, cool summers and cold, dry winters (Lantis 1942). The growing season is 100 to 120 days beginning in mid-May, but frost and snow may occur any day of the year (Rama1ey 1942). The cool, arid climate and sandy soils have resulted in a 'cold desert' plant association (Oosting 1956). Greasewood (Sarcobatus vermiculatus) and rabbit brush (Chrysothamous spp.) are the dominant vegetative species on the SLV floor (Lantis 1942, Enright 1971, u.s. Department of Interior 1979). In very alkaline soils, saltgrass (Distichlis stricta) is the only vegetative cover (U.S. Department of Interior 1979). Sedges (Carex spp.), rushes (Juncus balticus), spikerush (E1eocharis spp.), and saltgrass are common plants along wetland edges (Enright 1971, Szymczak 1986). Cattail (~ latifolia) and bulrush (Scirpus validus and~. paludosis) are the dominant emergent species (Enright 1971). Although precipitation within the SLV is low, spring run-off from the surrounding mountains provides ample water for irrigation (Hopper et al. 1975). Streams entering the northern part of the SLV percolate under the ground and continue flowing toward the center of the SLV under a layer of clay. This water emerges in central portions of the SLV as artesian wells (Carhart 1932). During the 1970's, irrigation techniques changed from flood irrigation to center pivot sprinklers. Water removed by center pivot sprinklers and reduced surface flows lowered the water table and subsequently reduced the number of artesian wells (U.S. Department of Interior 1979). The small human population in the SLV « 38,000) is concentrated in towns along the Rio Grande and Conejos Rivers (Mason 1974). The local economy is agriculturally based (Mason 1974). Major crops are irrigated potatoes, barley, vegetables, and hay (Hopper et al. 1975). Livestock production occurs throughout the SLV (Mason 1974). From 1964 through 1980, breeding duck estimates averaged 25,371 pairs, but declined after 1980 primarily because of decreasing habitat (Szymczak 1986). Mallards are the most abundant nester (Szymczak 1986). An average of 18,734 ducks winter in the SLV (1984-90 average, Colo. Div. Wi1d1., unpubl. data); most are mallards on the Monte Vista National Wildlife Refuge (MVNWR). Wintering mallards rest on open water maintained by pumping or artesian flow, and forage in nearby grain fields. METHODS Body Mass and Condition Mallards were captured on the MVNWR with Salt Plains bait traps (Szymczak and Corey 1976) and cannon nets (Dill and Thornberry 1950) in December 1986 and 1988, January 1987, 1988, and 1989, and February-March 1987, 1988, and 1989. Age and sex of all birds captured were determined using plumage characteristics (Carney 1964), and body mass (± 2 g), and wing length (to nearest mm) were recorded, and a condition index (estimated body fat / estimated fat-free body mass; Ringelman and Szymczak 1985) calculated for each. All mallards were banded with standard U.S. Fish and Wildlife Service leg bands. Mean body mass and condition indices were calculated for each trapping period. The Shapiro-Wilk statistic (Shapiro and Wilk 1965) was calculated using the UNIVARIATE Procedure (SAS Institute 1985) to test for normality of body mass and condition index distributions by age-sex class for each trapping period. Duncan's multiple range test was used to compare body mass and �7 condition index means by trapping period and age-sex class. To examine relations among body condition and trapping method, body mass of mallards captured in bait traps and cannon nets were compared for birds captured 11-18 January 1988 and 9-10 February 1989. . Body mass and condition index for mallards banded in 1987 or 1988 and recaptured in subsequent years were examined for similarity between years using linear regression. Body masses and condition indices were adjusted by subtracting the mean body mass and condition index for the corresponding agesex class and banding period to develop a relative condition index for additional between-year comparisons. Linear regression was used to examine relations between relative body mass and·condition in the banding year and subsequent years. Energy Intake Apparent metabolizable energy (AME) was measured for 3 grains grown in the SLV and fed upon by wintering mallards. Ten captive adult mallards (5 males and 5 females) were fed test food gg libitum for a minimum of 21 days before testing to assure gut morphology had adjusted to the diet (D. Johnson, Colo. State Univ., pers. comm.). Birds were placed in isolation cages and trials commenced when all birds were eating and had returned to their preacclimation body mass. If birds had not returned to pre-acclimation body mass, they would have been excluded from the trails, but all did return to pre-trial body mass. Before the 7-day trial, 8 meals exceeding gg libitum intakes were weighed to the nearest gram and divided into 2 portions, 1 to be fed in the morning and the other in the evening. Birds were weighed the day before trial initiation and again at its completion. Ducks were denied food for 8 h before the first day of the trial to allow food in the intestinal tract to be passed. Throughout the trial, birds were maintained at thermoneutrality (26°C, Smith and Prince 1973). Dry mass of meals fed, feces produced, and food not eaten were recorded. A composite fecal sample from days 3-6 was used for gross energy and nitrogen content measurements. After drying and grinding, composite grain and fecal samples were frozen and later analyzed for gross energy with a bomb calorimeter. Nitrogen content was determined by the Kjeldahl method, then multiplied by 6.25 to estimate protein content (Robbins 1983). The difference between mass of food fed and grain spilled was considered Lnt.ake.;differences between energy: intake and energy excre t ed was termed AME (Mhi'~~ ·~tici Reinecke 1984). T-tests were used to cOInpare'AME among foods. Determination of Foraging Rates Twelve captive birds (6 of each sex) were transported daily to an 64-ml enclosure erected in a field of standing barley on the MVNWR. After a 4 week acclimation period, birds appeared to be foraging in a manner similar to wild ducks. The enclosure was then moved to a site with abundant standing grain, and the birds were denied food for 18 h. Six mallards, 3 of each sex, were weighed to the nearest gram immediately before the trial. All captives were released ~ ~ into the enclosure, allowed to forage for precisely 5 min, then captured and reweighed. The amount of barley ingested was assumed to equal the difference between starting and ending body mass. �8 Estimation of Energy Expenditure Standard metabolic rates (SMR) were measured using the open circuit oxygen consumption method. Captive adult mallards, held in a pen with indoor and outdoor access and subject to natural photoperiod, were supplied with food (commercial poultry food and barley) and water ~ libitum. Individual test birds were denied access to food and water a minimum of 8 h before taking measurements. Birds were placed in a darkened respirometer (35.5 x 17.8 x 27.3 cm) between 2000 and 0400 h and room air pumped through the chamber at the rate of 1.6 l/min. Flowmeters measured flow into and out-of the chamber. For analysis, air from the respirometer was passed through columns of soda lime and drierite to remove COl and HlO, respectively. Oxygen content of the dried effluent air was measured with a Beckman F3 oxygen analyzer. Room air and a standard gas with 20.27% oxygen were used for calibration. All measures were adjusted to standard temperature and pressure. Lower critical temperature was estimated by taking mean SMR measures at -10°C and a line developed through the mean SMR measure and the intersection with the x axis at 42°C (mallard body temperature, unpubl. data) to estimate thermal conductance (McNab 1980). The point at which this line intersected the mean value of SMR measures made within the thermoneutral zone (Smith and Prince 1973) was identified as the lower critical temperature. Mean lipid reserves for each age-sex class were calculated by year to estimate distances the birds could travel if they migrated in response to severe weather. Flight energy was assumed to be 14 x SMR (Berger et al. 1971). Mean lipid levels were multiplied by the lipid energy content (assumed to be 9 kcal/g; Ricklefs 1974) to estimate energy reserves. Potential flight range was estimated by dividing energy reserves by flight energy (flight hours) and multiplying flight hours by the flight speed of mallards (assumed to be 64 kmjh; Whyte and Bolen 1988). Survival times were calculated using the same SMR and energy content estimates. Daily energy expenditure of free-living mallards in autumn was estimated as 3.0 x SMR (Prince 1979). Year-specific energy reserves were divided by daily energy expenditure to provide estimates of survival time, in the absence of food (fasting endurance), for the average mallard age-sex class. Mean monthly temperatures and departures from normal, total precipitation, snowfall, and departure of total precipitation from normal were obtained from monthly National Oceanic and Atmospheric Administration summaries for the Alamosa Airport, located 30 km east of the MVNWR. Generally, temperatures at the Alamosa Airport tended to be < 2°C lower than at the MVNWR. Snowfall in the SLV was variable, with the MVNWR usually receiving more snow than the Alamosa Airport. RESULTS Condition Indices Population ~.-Distributions of body masses and condition indices of mallards captured during each trapping period were not different from normal distributions (£ > 0.1) for each age-sex class. Body mass and condition indices were greatest in 1987-88 and least in 1988-89 (Tables 1.1 and 1.2). Adult females were in better condition than the other age-sex classes. Adult males and immature females were in similar condition, whereas �9 Table 1.1. Yearly and overall mean mass (SD) of mallards of different age-sex classes captured Dec-Mar, 1986-89, in the San Luis Valley, Colorado. Comparisons with letters a-c denote differences in the means among years (a 0.05, Duncan's Multiple Range Test). Letters w-z denote differences among age-sex classes within a year (a - 0.05, Duncan's Multiple Range Test). Yearly overall means are grand means rather than weighted means. Age Sex Adult Female Adult Male Immature Female 1986-87 933(87)by 948(78)ay 1988-89 909(77)cy Overall 931(82)y (N - 192) (N - 411) (N - 324) 1,043(100)bw (N - 573) 1,088(93)aw (N - 884) 1,028(82)cw 1,054(95)w (N - 602) (N - 2,059) (N - 927) 904(82)az 554) 896(81)az 262) (N - 844(74)bz 887(83)z (N - 201) (N - 1,017) 978(90)bx 594) 1,015(89)ax (N - 595) (N - (N - Immature Male 1987-88 (N - 959(81)cx 987(90)x 244) (N - 1,473) Table 1.2. Yearly and overall mean (~) condition indices of mallards of different age-sex classes captured Dec-Mar, 1986-89, in the San Luis Valley, Colorado. Comparisons with letters a-c denote differences in the means among years (a - 0.05, Duncan's Multiple Range Test). Letters w-z denote differences among age-sex classes within a year (a - 0.05, Duncan's Multiple Range Test). Yearly overall means are grand means rather than weighted means. Age Sex 1986-87 1987-88 1988-89 Overall Adult Female 14.5(4.9)bw (N - 192) l5.3(4.5)aw (N - 411) 13.2(4.6)cw (N - 324) Adult Male 12.7(4.7)bx (N - 573) 14.9(4.2)aw G! - 884) 13.5(4.5)x 12.7(4.1)bw (N - 1,059) (N - 602) Immature Female l4.0(4.5)aw (N - 262) 14.3(4.5)ax (N - 554) l2.0(4.6)bwx 13.5(4.7)x (N - 201) (N - 1,017) Immature Male 11.6(4.4)by (N - 594) 13.2(4.2)ay (N - 595) 10.9(4.2)bx 12.0(4.4)y (N - 1,473) (N - 244) 14.4(4.7)w (N - 927) �10 immature males were in the poorest condition. Body mass and condition of adult males and females and immature males were greatest in 1987-88 (Tables 1.1 and 1.2). Males had greater condition indices in 1987-88 than the other 2 years, whereas condition indices of adult females were different in all three years. Immature females had similar body mass and condition in 1986-87 and 1987-88, and both parameters were less in 1988-89. Each year, adult females were in the best and immature males the poorest condition. Adult males and immature females were in similar condition in 1987-88 and 1988-89, but immature females were in better condition in 198687 (Table 1.2). Condition indices of adult females generally reached lowest levels in January before beginning to increase through early March (Table 1.3). Condition of immature females decreased through February, but increased thereafter. Condition indices of adult and immature males were greatest in the first trapping period each year, whether in December or January, and rapidly dropped to a relatively constant level for the rest of the trapping season. Table 1.3. Mean (SQ) condition index, by trapping period, of mallards captured in the San Luis Valley, Colorado. Letters a-d compare means by agesex class within a banding period (a - 0.05, Duncan's Multiple Range Test). Letters t-z compare means by banding period, within an age-sex class (a 0.05, Duncan's Multiple Range Test). Year 1986-87 1988 1988-89 Trapping Period Adult Female 19.9(4.4)at (N - 18) Jan 13.6(4.7)avw (N - 121) Feb 14.8(3.7)auv (N - 56) Jan 15.9(4.4)au (N - 274) Jan-Feb 13.0(5.2)avw (N - 43) Feb 12.1(3.1)aw (N - 18) Feb-Mar 14.6(4.0)auv (N - 91) 13.9(6.0)auvw Dec (N - 21) 12.3(4.6)aw Jan (N - 219) Feb 14.0(3.3)auvw (N - 25) Feb-Mar 15.3(3.8)auv (N - 77) Dec Adult Male 18.0(3.6)abt (N - 78) 12.5(3.9)bwx (N - 343) 10.4(3.5)cx (N - 165) 15.4(4.0)au (N - 783) 13.3(3.4)avw (N - 34) 10.9(3.0)ax (N - 46) 12.1(3.5)bwx (N - 152) 14.6(4.3)auv (N - 42) 12.4(4.2)awx (N - 553) 11.7(3.1)bcwx (N - 37) 12.0(3.8)bwx (N - 134) Immature Female Immature Male 17.1(4.7)bt 16.5(3.8)bt (N - 30) (N - 63) 13.7(4.0)atuv 11.8(4.0)buv (N - 169) (N - 330) 13.3(3.8)btuv 9.7(3.6)cv (N - 69) (N - 216) 14.8(4.3)btu 13.9(3.8)ctu (N - 390) (N - 495) 14.0(3.3)atu 10.6(4.6)bv (N - 45) (N - 16) 9.7(4.9)av 9.7(2.9)av (N - 22) (N - 11) 12.6(4.5)buv 10.0(3.8)cv (N - 122) (N - 144) 13.9(4.3)atuv 12.6(3.6)auv (N - 19) (N - 18) 10.9(4.4)auv 10.6(4.4)av (N - 163) (N - 225) 13.1(4.5)abtuv 10.5(2.7)cv (N - 15) (N - 20) 11.9(4.4)buv 10.5(3.7)cv (N - 47) (N - 57) �11 Effect Qf Capture Method. - In January 1988, mallards captured in cannon nets were in better condition than those captured in bait traps (Table 1.4). Differences were significant for all age-sex classes except adult females (~- -4.17, 623 df, £ < 0.0001; ~ - -1.83, 416 df, £ - 0.0679; ~ - 2.47, 348 df, f - 0.0139; and ~ - -1.16, 130.8 df, £ - 0.2499 for adult males, immature males, immature females,and adult females respectively). On 9-10 February 1989, condition indices were greater for mallards captured with cannon nets (Table 1.4), but only differences for immature males approached significance (~ - -1.64, 30 df, £ - 0.1108; f > 0.15 for other age-sex class comparisons). Table 1.4. Mean condition indices (SE) of mallards captured 11-18 January 1988 and 9-10 February 1989, in the San Luis Valley, Colorado, in cannon nets and Salt Plains bait traps. Year Trap Method Male b,gylt Female Immat1U:~ Male Female 1988 Cannon Net 16.8(3.8) n - 88 16.4(3.8) n - 63 14.9(3.6) n - 38 16.7(3.6) n - 32 Bait Trap 14.9(4.1) n - 537 15.8(4.7) n - 191 13.7(3.8) n - 380 14.7(4.3) n - 318 Cannon Net 12.5(3.1) n - 56 12.4(3.8) n - 37 11.2(2.5) n - 18 12.3(4.2) n - 28 Bait Trap 11.7(3.0) n - 22 12.4(3.9) n - 12 9.5(3.2) n - 14 9.8(3.3) n-6 1989 Recaptureg Indivigyals. - Mallards banded and then recaptured in 1988 had lower mass and condition indices at recapture than at the time of initial capture (l - 16.96, 1,204 df, f - 0.0001 and l - 5.83, 1,204 df, f - 0.0166, for body mass and condition indices, respectively). At recapture, immature birds had lower body mass than unmarked birds trapped at the same time, whereas adult males recaptured were similar to unmarked birds. In 1989, recaptures did not differ in body mass (l - 2.67, 1,500 df, £ - 0.1026) or condition index (l - 0.51, 1,499 df, f - 0.4753) between initial capture and recapture. All age-sex classes of unmarked and marked birds showed similar body mass each banding period. One hundred and twenty mallards banded in 1986-87 were recaptured in 1987-88. Only 4 adult females from 1986-87 were recaptured in 1988, and no relation of condition or relative condition (condition index - mean condition index) between the 2 years was detected (f 0.00, 1,3 df, £ - 0.9998 and l -0.00, 1,2 df, £ - 0.9892 for condition and relative condition, respectively). Condition in 1986-87 was related to condition in 1987-88 for adult males (f - 13.39, 1,50 df, £ - 0.0006), and immature males (f - 8.66, 1,36 df, £ - 0.0057), but not for immature females (f - 0.44, 1,5 df, £ - 0.5362). Relative condition classes showed the same relations (Table 1.5; Fig. 1.1 for males) �12 co CO I 15 I"CO 12 (J) ~ 9 C 6 C 3 a 0 C (3) a U CD > ......., ~ --...- Immature ·····0······ ......, ."0 Adult o o , 00 O. .:" (6) o • ..'. . -~0 ~• 0 ~ , .' 0_,," • - 8.,-0;. _ .,0 • -:'0 ",'. • • " , • -• 0 •• " (9) . • o " (12) CD a: (15)(15) (12) (9) (6) (3) 0 3 6 9 12 15 Relative Condition in 1986-87 Figure 1.1. Relative condition indices of adult and immature males captured in 1986-87 and recaptured in 1988 in the San Luis Valley, Colorado. The solid line represents the least squares linear regression line for adult males and the dotted line the regression line for immature males. �Table 1.5. Linear regression relations between condition index of mallards at the time of initial capture and recapture in subsequent years in the San Luis Va1ley, Colorado. l:;aIlt1U;:!il Initial X!ilSlI': Recapture a& bb r2 i'" Error df £ Age Sex Adult Male 1986-87 1986-87 1988 1988 1988-89 1988-89 0.46 -0.71 0.16 0.40 -0.34 0.23 0.82 1.33 0.05 8.93 9.13 4.92 49 32 91 0.0044 0.0050 0.0290 Female 1988 1988-89 0.42 -1.08 0.21 4.30. 17 0.0546 Male 1986-87 1986-87 1988 1988 1988-89 1988-89 0.97 -0.81 0.38 0.97 0.01 0.18 0.44 0.720.27 18.32 3.43 13.68 30 17 38 0.0002 0.0827 0.0007 Female 1986-87 1986-87 1988 1988 0.34 0.38 0.24 1988-89 -0.82 2.39 0.31 1988-89 0.96 -0.30 0.58 1.59 1.40 16.05 6 4 13 0.2634 0.3224 0.0017 Immature • Slope of the regression function. b Intercept of the regression function. C Two-tailed test of the hypothesis of the slope ~ o. Fifty-seven mallards banded in 1986-87, including only 1 adult female, were recaptured in 1988-89. Condition indices in 1986-87 were positively related to condition indices in 1988-89 for adult males (£ - 9.24, 1,31 df, f - 0.0048), as were relative condition indices (Table 1.5; Fig. 1.2). Neither condition indices nor relative condition indices were related for immature mallards (~ - 2.57, 1,16 df, f - 0.1283 and ~ - 1.56, 1,3 df, £ - 0.3001, for male and female condition indices, respectively; Table 1.5 for relative condition indices; and Fig. 1.2 for immature males). One hundred and sixty-three mallards captured in 1987-88 were recaptured in 1988-89. Condition indices of adult females captured in 1987-88 were not related to indices in 1988-89 (~ - 2.22, 1,16 df, f - 0.1553), but other agesex classes were positively related (~- 5.44, 1,90 df, f - 0.0219; ~ - 17.14, 1,37 df, f - 0.0002; and ~ - 15.18, 1,12 df, f - 0.0021 for adult males, immature males, and immature females, respectively). Relative condition indices in 1987-88 were positively related for all age-sex classes (Table 1.5; Figs. 1.3 and 1.4). Metabolizable Energy Three grains grown in the SLV were measured for metabolizable energy: triumph and steptoe barley, and field peas. Gross energy of steptoe barley was 18.85 (~ - 0.24) kj/g, of triumph barley l7.90(~ - 0.19) kj/g, and of field peas 18.37 (~ - 0.05) kj/g. Overall, birds maintained on steptoe barley gained 13.2 (~ - 21.6) g, those on triumph barley gained 20 (~ 33.3) g, whereas those fed field peas lost an average of 19.3 (~ - 19.8) g. Apparent metabolizable energy was similar for steptoe barley and field peas (~- 0.27,1 df, f - 0.4161), while the AME of triumph barley was less than the �14 . I i 0') CO I CO CO 15 -.- Adult 0') "r- iO c: Immature ······0······ X CD 5 "0 c: c: a • c: a 0 ,~" 0 0cl' ~ " . 0,'· •o· 0 • -+-' "0 • •° °• • .. . (5) .: ,, ._~ (10) -+-' -C'UCD (15) a: (15) ,, ,, • ' • • •• 0 o (10) (5) 0 5 10 15 Relative Condition Index in 1986-87 Figure 1.2. Relative condition indices of adult and immature males captured in 1986-87 and recaptured in 1988-89 in the San Luis Valley, Colorado. The solid line represents the least squares linear regression line for adult males and the dotted line the regression line for immature males. :.~'~'. .. �15 15 -..- (j) COI CO CO (j) .,.... .e e _ a ...._ "'C e a 0 CD Adult 12 9 6 0 • • •• • I· 3 •• •• 0 (3) .,' 0 •• ••• 0 o • (6) ._ ...-> (9) CD (12) •• • (15\15) ., • • • 0 • • ~ a:: •• Immature .....-0 ...... • (12) (9) (6) (3) 0 3 6 9 12 15 Relative Condition in 1987-88 Figure 1.3. Relative condition indices of adult and immature males captured in 1987-88 and recaptured in 1988-89 in the San Luis Valley, Colorado. The solid line represents the least squares linear regression line for adult males and the dotted line the regression line for immature males. �16 (j') COI 15 CO 12 CO (j') .,.... 9 C 6 C a .+-' .- -.-- Adult Immature ······0······ • 0:> o..~·· 3 o 0 • "'0 C (3) a 0 (6) (].) > .- (9) - m (12) ~ (15)(15) • • 0 • ..- .' • • o • (12) (9) (6) (3) 0 3 6 9 12 15 Relative Condition in 1987-88 Figure 1.4. Relative condition indices of adult and immature females captured in 1987-88 and recaptured in 1988-89 in the San Luis Valley, Colorado. The solid line represents the least squares linear regression line for adult females and the dotted line the regression line for immature females. �17 others (~ ~ 6.15,1 df, f ~ 0.0513 and ~ - 4.61, 1 df, f ~ 0.0680 for comparisons of triumph and steptoe barley and field peas, respectively; Table 1. 6). Table 1.6. Mean (£Q) daily intake, fecal energy (Kj/day), and apparent metabolizable energy (Kj/day) of field peas and barley grown in the San Luis Valley, Colorado. Food Intake energy (Kj/day) Fecal energy (Kj/day) Apparent metabolizable energy (Kj/g intake) Peas 787.9(232.8) 193.6(67.0) 13.91(0.42) Steptoe 984.0(213.6) 258.2(51.9) 13.85(0.56) Triumph 764.5(185.4) 210.1(49.8) 12.97(0.26) Feeding Trials Drift in the electronic balance used in the field-feeding trials resulted in some erroneous body mass measurements; these measurements were excluded from analyses. Females ingested barley at the rate of 0.92 g/min (~ - 0.77, range 0.0-2.4 g/min, n - 27) and males consumed 1.50 g/min (SQ - 0.99, range 0.0-4.0, n - 31) from fields on MVNWR. There were differences in the rate of consumption between sexes (F - 6.05, 1,54 df, ~ - 0.0170) and among individuals (F - 8.69, 1,54 df, ~ - 0.0047), but no individual*sex interaction was detected (F - 0.89, 1,54 df, ~ - 0.3507). Males consumed standing grain heads, whereas females were only observed foraging on shelled grain. Standard Metabolic Rate SMR trials require that the birds be inactive long enough for a stable rate of oxygen consumption to be identified (approximately 45 min). Only 11 SMR measurements were obtained under these conditions (Fig. 1.5). The basal rate was estimated as 368 (~ - 75, n - 5) kj/day, the mean of the values obtained at 20-30 °c. At -9 to -10°C, SMR was 675 (~ - 189, n - 6) kj/day. Based on these measures, the lower critical temperature is about 13 to 14°C. DISCUSSION Although age and sex variations in body mass of SLV mallards are similar to those found in other wintering mallard populations (Sugden et al. 1974, Owen and Cook 1977, White 1982, Jorde et al. 1984, Delnicki and Reinecke 1986, Whyte et al. 1986), mean body mass appears to be lower (Table 1.7). However, structural size does not seem to account for the lower body masses of SLV wintering mallards, because wing lengths, a common index of structural size (Ringelman and Szymczak 1985), were no smaller for SLV mallards than for other wintering populations (Table 1.8). Environmental conditions could, however, account for low mean body masses either directly by resulting in a negative energy balance (the forced hypothesis), or indirectly where low body mass is an adaptive response to conditions (the adaptive hypothesis). I used �18 1,100 • 1,000 900 • 800 700 > CO --o_ 600 0 500 ~ 400 300 200 100 0 (20) Figure 1.5. (10) 0 10 20 30 40 Ambient Temperature Standard metabolic rate measurements of captive, post- absorptive, adult mallards measured using the open circuit oxygen consumption method at temperatures above and below the lower critical temperature in the San Luis Valley, Colorado. 50 �19 energetic data to explore these alternative hypotheses. Table 1.7. Mean body mass (g) for wintering mallard populations. Location Reference· Alberta Male agYlt Female Male Imm51tyte Female Male Qo!Ut!ined Female 1,221 (1) N - 1,479 England New Jersey (2) 1,183 N. - 594 1,068 N. - 774 1,111 N - 135 1,106 N - 96 1,400 106 (3) N Missouri (4) Missouri (5) Missouri (6) Mississippi (7) Texas (8) Oklahoma (9) SLV (10) 1,020 N. - 103 1,102 N - 143 1,220 N - 215 1,246 1,095 N - 1,308 N - 453 1,237 1,088 N - 87 N. - 42 1,196 1,052 N - 92 N - 71 1,053 930 N - 2,059 N - 927 1,059 H - 703 1,264 N - 97 990 N - 88 1,133 N - 66 1,040 1,181 N - 169 N - 188 1,214 996 N - 19 N - 20 1,123 976 1,160 H - 105 N - 119 984 881 1,019 N - 1,473 N - 1,017 1,008 906 • (1) Sugden et a1. (1974); (2) Owen and Cook (1977); (3) Figley and VanDruff (1982); (4) White (1982); (5) Heitmeyer (1985); (6) calculated from Combs (1987); (7) De1nicki and Reinecke (1986); (8) Whyte et al. (1986); (9) Gordon (1981); (10) this study. �20 S Table 1.8. Mean wing lengths populations. (mm) reported for wintering mallard Reference Adult Male Owen and Cook (1977) 274 338 N- Female W'hite (1982) N Delnicki and Reinecke (1986) 293 1,308 297 N - 2,059 N This study a 259 465 275 - 103 N- 276 N - 453 281 N - 927 Male N N N Immature Female 273 - 121 286 - 169 284 - 1,473 257 N - 94 272 N - 88 N N 270 - 188 271 - 1,017 Techniques for measuring wing length may have varied between studies. The Forced Hypothesis Severe environmental conditions, such as low ambient temperatures or food limitations, could regulate boodymass and condition of mallards wintering in the SLV. If ambient temperature directly controls body condition by increasing mallard thermoregulatory demands, then their condition should have been related to ambient temperatures before and during our trapping efforts. Yet, mallards in the SLV were in better condition in 1987-88 than the other two trapping years, even though December and January temperatures were lowest in 1987-88 (Table 1.9). Therefore, ambient temperature does not appear to directly control body condition. Similarly, no relations are apparent among condition and December and January snowfall (Table 1.9). These results were not unexpected, because SMR measurements suggest that mallards acclimate well to cold temperatures. Like many other avian species, such acclimatization may include the ability to restrict carbohydrate use (Marsh and Dawson 1982), and vasoconstriction in the bill and legs to reduce heat loss (King and Farner 1961, Hagan and Heath 1980). �21 Table 1.9. Mean and departures from normal for monthly temperature (OC), total and departure from normal for precipitation (em), and snowfall (em) recorded at the Alamosa Airport, Alamosa, Colorado, December - March 1986-87, 1987-88, and 1988-89. Month Year Dec Jan Feb &r Dec Jan Feb Mar Dec Jan Feb Mar Temperature Precipitation Mean Departure from Normal Total Snow Departure from Normal 1986 -6.4 1987 -10.3 1987 -4.8 1987 -0.6 1987 -9.6 1988 -15.3 1988 -8.2 1988 -0.3 1988 -7.9 1989 -9.4 1989 -5.8 1989 2.9 1.3 -1.4 0.3 -0.3 -1.8 -6.4 -3.1 -0.1 -0.1 -0.6 -0.7 3.1 0.3 1.7 1.2 0.7 1.3 0.7 0.6 O.~ 0.3 0.8 0.7 0.3 4.8 32.5 17.8 9.9 19.1 15.2 7.4 8.6 3.6 13.2 7.6 2.5 -0.6 1.0 0.6 -0.2 0.4 -0.0 -0.0 -0.5 -0.6 0.1 0.1 -0.7 Using mean ambient temperatures to determine daily energy requirements of SLV mallards may cause an overestimation of these energy requirements. SLV mallards roost on open water areas where water temperatures may be several degrees above freezing. In addition, the steam that rises from the water surface may produce a warmer microclimate than general SLV ambient temperatures as recorded at the Alamosa Airport. Also, mallards may use daily solar radiation (Lustick 1969, Heppner 1970) and may alter their behavior (Lustick 1973, Brodsky and Weatherhead 1985) to reduce thermoregulatory energy costs. Proximate factors, such as snow cover and waste grain density, are important in determining energy intake by field-feeding ducks. Jorde et al. (1983) reported that mallards in Nebraska use fields in which grazing cattle trampled the snow, thereby making grain available to ducks. Likewise, waterfowl wintering on the MVNWR must field-feed because little food remains in wetlands. Captive mallards chose durum wheat and barley over hard spring wheat (Clark et al. 1986), a preference that was attributed to the difference in handling time (i.e., the time required for the bird to remove the kernel from the head and ingest it). Clark et al. suggested the rate of energy intake was more important than energy content of the food. Our observations of females not using standing grain heads suggest different handling times for males and females. Prince (1979) suggested free-living mallards required 3.0 x SMR for daily energy expenditure (DEE). Based on monthly mean SLV temperatures during 1964-88, if the lower critical temperature is 13°C and SMR at -10°C is 675 kj/day (SMR measurements), then a mallard would have to consume 129.9 g of barley/day in November, 150.3 g of barley/day in December, and 154.5 g of barley/day in January to meet DEE. Therefore, a female mallard would have to field-feed for 141 min/day in November, 162 min/day in December, and 168 min/day in January. A male would need to forage 87 min/day in November, 99 �22 min/day in December, and 102 min/day in January to meet DEE. A SLV mallard would need to consume 13.35 kg of triumph barley from 1 November through 31 January to meet DEE. Thus, a wintering population of 20,000 mallards would require 267 metric tons of triumph barley from November through January. If triumph barley yields 51.4 bujha and bushel mass is 24.5 kg/bu (Dillion 1989), triumph barley would produce 1,259 kgjha. Consequently, 212 ha would be needed to support 20,000 wintering mallards from November through January assuming the ducks completely utilized the grain. During the three years of our study, from 96 to 167 ha were cultivated on MVNWR (S. Brock, pers. comm.), suggesting that the low body masses observed may result from insufficient food supplies if, in fact, 212 ha are needed to support the SLV population and mallards only foraged on the refuge. Although food may be a factor limiting body condition of SLV mallards, the year with greatest grain production (167 ha produced 38,500 bu in 1989; S. Brock, pers. comm.) was also the year that mallards had the lowest condition indices. Conversely, in 1986 and 1987, substantially less grain was produced on MVNWR (23,600 and 26,300 bu in 1986 and 1987, respectively; S. Brock, pers. comm.), but mallards were in better condition. Presently, grain availability in fields adjacent to MVNWR appears to have little effect on mallard body condition from December through February. Mallards may have foraged in grain fields adjacent to MVNWR to supplement intake, although our observations suggest few mallards forage off MVNWR from December through February. In summary, low body masses ("poor" condition) of mallards wintering in the SLV are not entirely attributable to food availability because the winter with the most food available corresponded to the year mallards were in poorest condition. Additionally, ambient temperatures and snow fall do not account for yearly differences in winter body condition. The Adaptive Hypothesis There may be selective advantages for low winter body mass in the SLV. Consistency of relative condition indices between years suggests that body condition is controlled endogenously. In support of this, captive mallards in the SLV were maintained with ~ libitum barley supplemented with high-protein poultry pellets; these birds maintained body masses similar to wild birds captured in the SLV (mean mass for 8 adult males was 1,178 g (SQ - 79) and for 9 adult females was 1,114 g (SQ - 86) on 5 January 1989; unpub1. data). Selective forces that may determine optimum winter body mass are the risks of starvation and predation (Lima 1986): body mass should decrease as the predictability of food resources increases or as predation risk rises. In Lima's model, optimal body mass decreases with increases in the frequency of predator attacks or probability that attacks will be successful. Advantages of reduced body mass would be reduced foraging time and an increased probability of evading predator attacks. Conversely, heavier body mass reduces the risk of starvation in unpredictable environments. Predictable, but not plentiful, food resources for wintering SLV mallards are barley grown and left standing in fields on the MVNWR and waste grain in fields adjacent to the refuge. Mean lipid reserves would allow birds to survive 2.5-4 days (Table 1.10) at 3-4 times SMR (Prince 1979) or to make the 400 km flight to the Rio Grande River Valley in New Mexico or the 600 km Table 1.10. Mean body mass, estimated basal metabolic rate, mean estimated lipid reserves, energy content of lipid reserves, and estimated flight range �23 and survival time for San Luis Valley mallards. Age Sex Body mass SMR Fat (g) (kcal/h) (g) Fat energy (kcal) Flight range (km) 933 948 909 3.48 3.52 3.41 120 127 107 1,080 1,143 963 1,421 1,485 1,293 4.3 4.5 3.9 1986-87 1,043 1987-88 1,088 1988-89 1,028 3.78 3.90 3.74 119 143 112 1,071 1,287 1,008 1,293 1,510 1,235 3.9 4.6 3.7 896 904 844 3.38 3.40 3.24 112 114 84 1,008 1,026 756 1,363 1,382 1,069 4.1 4.2 3.2 978 1986-87 1987-88 1,015 1988-89 959 3.60 3.70 3.55 101 120 91 909 1,080 819 1,152 1,331 1,056 3.5 4.1 3.2 Year Adult Female 1986-87 1987-88 1988-89 Adult Male Immature Female 1986-87 1987-88 1988-89 Immature Male Survival time (d) flight to the Southern High Plains in Texas (Table 1.10). During 3 field seasons, snow sufficient to cover the barley left standing in refuge fields occurred only for about 1 week in January 1987 (Table 1.9); during that period, many birds succumbed to starvation (unpubl. data), but I did not observe any obvious migratory flights of mallards leaving the SLV. Few data have been presented to substantiate that predators remove weakened individuals from small mammal or avian populations (Temple 1987). Temple suggested that the degree to which predators removed weakened individuals was influenced by how difficult the prey was to kill. Difficultto-kill species would show the greatest deviations (e.g. numbers of parasites, body condition, age, number of injuries) between the individuals killed and the population. Factors that help determine how difficult prey is to kill include environmental complexity, escape maneuvers of the prey, and once caught, how difficult the prey is to dispatch. In the SLV, raptors account for most mallard predation. Mallards may increase their probability of detecting predators (Moriarty 1976), and the complexity of their environment by flocking (Rubenstein 1978, Pulliam and Millikan 1982). When attacked by a raptor, escape maneuvers are a mallard's last defense. Most avian predators' easily kill mallards once the birds are caught. Bald eagles (Ha1iaeetus 1eucocepha1us) were the primary predator of waterfowl wintering in the SLV, although we also observed golden eagles (AQuila chhYsaetos), peregrine falcons (~ pere~rinus), and prairie falcons (~ mexicanus) capturing wintering waterfowl. Attacks usually occurred when waterfowl were roosting. When a raptor approached, the flock flushed and circled until the raptor either made a kill or ended the attack. Birds separated from the main flock were usually targeted for attack. When singled out by a raptor, a flying mallard's principle escape maneuver was to attempt to outfly the predator until the mallard could land on open water and dive, or land in vegetation and hide. Lower body mass of mallards wintering in the SLV may be advantageous in escaping avian predators, because reductions in wing �24 loading (g/cm2 wing area) increase maneuverability (Greenwalt 1975). In 198788, when mallard body condition was greatest, a severe outbreak of avian cholera resulted in numerous carcasses; eagles scavenged these carcasses, thereby reducing their predation on live birds. Low body mass of mallards wintering in the SLV may also reduce flight energetics at the high elevation (2,300 m). Most interest in altitude physiology has focused on the effects of hypoxia (e.g., Monge and Whittembury 1976, Cerretelli 1987). Little interest has been shown on other effects (such as reduced air density) of high-altitude environments. At the 2,300 m elevation of the SLV, air density is about 79.8% of the air density at sea level (Ava~lone and Baumeister 1987). Energy per unit distance flown at 2,300 m altitude would be 25.4% greater than a similar flight at sea level when all variables other than air density are held constant (Greenwalt 1975). Alternatively, if variables other than body mass are constant, a bird flying a given distance at sea level could weigh 12.0% more and expend the same energy as a bird flying the same distance at 2,300 m (Greenwalt 1975). However, mallards wintering in Mississippi (26-33 m elevation) weighed 17-20% more than mallards wintering in the SLV (Delnicki and Reinecke 1986; Table 1.7); which is more than the estimated body mass differences expected if flight energetics alone limited SLV mallard body mass in the winter. I conclude that low body mass of mallards wintering in the SLV does not directly reflect stressful winter conditions, but instead may be a response to an unusual wintering environment. Although ambient temperatures in ~he SLV appear severe, microclimates of winter roosts probably are not severe. Grain production appears to be insufficient for this wintering population, but years with greatest grain production on MVNWR did not result in greater condition indices. Altitude may be an important factor controlling body mass by influencing flight energetics and the ability to elude avian predators. While aspects of both the forced and adaptive hypotheses probably influence body mass of mallards wintering in the SLV, my evidence suggests low body masses are more adaptive than forced. My results emphasize the need to include environmental parameters other than temperature and precipitation when evaluating an animal's adaptive responses to environmental conditions. LITERATURE CITED Avallone, E. A., and T. Baumeister, III. (eds.) 1987. Mark's standard handbook for mechanical engineers. McGraw-Hill Book Co., New York. 1,239pp. Bailey, R. O. 1979. Methods of estimating total lipid content in the redhead duck (Aythya americana) and an evaluation of condition indices. Can. J. Zool. 57:1830-1833. Bain, G. A. C. 1980. The relationship between preferred habitat, physica~ndition and hunting mortality of canvasbacks (Aythya valisineria) and redheads (Aythya americana) at Long Point, Ontario. M. S. Thesis, Univ. Western Ontario, London. 38pp. Berger, M., J. S. Hart, and O. Z. Roy. 1971. Respiratory water and heat loss of the black duck during flight at different temperatures. Can. J. Zool. 49:767-774. �25 Brodsky, L. M., and P. J. Weatherhead. 1985. Variability in behavioural response of wintering black ducks to increased energy demands. Can. J. Zool. 63:1657-1662. Carhart, A. H. 1932. Colorado. Coward - McCann, Inc., New York, NY. 322pp. Carney, S. M. 1964. Preliminary keys to waterfowl age and sex identification by means of wing plumage. U. S. Fish Wildl. Serv., Spec. Sci. Rep. -- Wildl. 82. 47pp. Cerretelli, P. 1987. Extreme hypoxia in air breathers: some problems. Pages 137-150 in P. Dejours, ed. Comparative physiology of environmental adaptations, Vol. 2. 8th Conf. European Soc. Camp. Physiol. Biochem. Strasbourg 1986. S. Karger AG, Basel, Switzerland. 224pp. Chappell, W. A., and R. D. Titman. 1983. Estimating reserve lipids in greater scaup (Aythya marila) and lesser scaup (a. affinis). Can. J. Zool. 61:35-38. Clark, R. G., H. Greenwood, and L. G. Sugden. 1986. Influence of grain characteristics in optimal diet of field-feeding mallards Anas platyrhynchos. J. Appl. Ecol. 23:763-771. Combs, D. L. 1987. Ecology of male mallards during winter in the Upper Mississippi Alluvial Valley. Ph.D. Thesis, Univ. of Missouri, Columbia. 22lpp. Delnicki, D., and K. J. Reinecke. 1986. Mid-winter food use and body weights of mallard and wood ducks in Mississippi. J. Wildl. Manage. 50:43-51. Dill, H. H., and W. H. Thornberry. 1950. A cannon projected net trap for capturing waterfowl. J. Wildl. Manage. 14:132-137. Dillion, M. A. 1989. 1989 small grain research report. Colorado State University Cooperative Extension, Center, Colo. 14 pp. Enright, C. A. 1971. An analysis of mallard nesting habitat on the Monte Vista National Wildlife Refuge, Colorado. M.S. Thesis, Colorado State University, Fort Collins. l13pp. Evans, P. R., and P. C. Smith. 1975. Studies of shorebirds at Lindisfarne, Northumberland. 2. Fat and pectoral muscle as indicators of body condition in the bar-tailed godwit. Wildfowl 26:64-76. Fenneman, N. M. 1931. Physiography of western United States. McGraw-Hill Co., Inc., New York, NY. 534pp. Figley, W. K., and L. W. VanDruff. 1982. The ecology of urban mallards. Wildl. Monogr. 81:1-39. �26 Gauthier, G., and J. Bedard. 1985. Fat reserves and condition indices in greater snow geese. Can. J. Zool. 63:331-333. Gordon, D. H. 1981. Condition, feeding ecology, and behavior of mallards wintering in northcentral Oklahoma. M. S. Thesis, Oklahoma State Univ, Stillwater, OK. 66pp. Greenwalt, C. H. 1975. The flight of birds. Trans. Amer. Phil. Soc. 65:1-67. Greenwood, H. R., R. G. Clar~, and P. J. Weatherhead. 1986. Condition bias of hunter-shot mallards (Anas platyrhynchos). Can. J. Zool. 64:599-601. Hagan, A. A., and J. E. Heath. 1980. Regulation of heat loss in the duck by vasomotion in the bill. J. Therm. BioI. 5:95-101. Haramis, G. M., J. D. Nichols, K. H. Pollock, and J. E. Hines. 1986. The relationship between body mass and survival of wintering canvasbacks. Auk 103:506-514. Heitmeyer, M. E. 1985. Wintering strategies of female mallards related to dynamics of lowland hardwood wetlands in the upper Mississippi delta. Ph.D. Thesis, Univ. Missouri, Columbia. 378pp. _____ , and L. H. Fredrickson. 1981. Do wetland conditions in the Mississippi Delta hardwoods influence mallard recruitment? Trans. N. Am. Wi1dl. Nat. Resour. Conf. 46:44-57. Hepp, G. R. 1986. Effects of body weight and age on the time of pairing of American black ducks. Auk 103:477-484. ----- , R. J. Blohm, R. E. Reynolds, J. E. Hines, and J. D. Nichols. 1986. Physiological condition of autumn-banded mallards and its relationship to hunting vulnerability. J. Wildl. Manage. 50:177183. Heppner, F. 1970. The metabolic significance of differential absorption of radiant energy by black and white birds. Condor 72:50-59. Hohman, W. L., T. S. Taylor, and M. W. Weller. 1988. Annual body weight change in ring-necked ducks (Aythya collaris). Pages 257-269 in M. W. Weller, ed. Waterfowl in winter. Univ. Minnesota Press, Minneapolis. Hopper, R. M., A. D. Geis, J. R. Grieb, and L. Nelson, Jr. 1975. Experimental duck hunting seasons, San Luis Valley, Colorado, 1963-1970. Wildl. Monog. 46:1-68. Jorde, D. G., G. L. Krapu, and R. D. Crawford. 1983. Feeding ecology of mallards wintering in Nebraska. J. Wildl. Manage. 47:1044-1053. �27 King, J. R., and D. S. Farner. 1961. Energy metabolism, thermoregulation and body temperature. pp. 215-288 in A. J. Marshall, ed. Biology and comparative physiology of birds. Vol. II. Academic Press, New York, NY. Krapu, G. L. 1981. The role of nutrient reserves in mallard reproduction. Auk 98:29-38. LaGrange, T. G., and J. J. Dinsmore. 1988. Nutrient reserve dynamics of female mallards during spring migration through central Iowa. Pages 287-297 in M. W. Weller, ed. Waterfowl in winter. Univ. Minnesota Press, Minneapolis. Lantis, D. W. 1942. Sage of the San Luis Valley in Colorado. Folks and Fortunes 1:38-40. Lima, S. L. 1986. Predation risk and unpredictable feeding conditions: determinants of body mass in birds. Ecology 67:377-385. Lustick, S. I. 1969. Bird energetics: effects of artificial radiation. Science 163:387-390. _____ . 1973. Cost-benefit of thermoregulation in birds: influences of posture, microhabitat selection, and color. Pages 265-294 in W. P. Aspey and S. I. Lustick, eds. Behavioral energetics: the cost of survival in vertebrates. Ohio State Univ. Press, Columbus, OH. Marsh, R. L., and W. R. Dawson. 1982. Substrate metabolism in seasonally acclimatized American goldfinches. Am. J. Physiol. 242:R563-R569. Mason, J. 1974. San Luis Valley resource area -- social -- economic profile. Western Interstate Commission for Higher Education, Boulder, CO. 2l9pp. McNab, B. K. 1980. On estimating thermal conductance in endotherms. Physiol. Zool. 53:145-156. Miller, M. R., and K. J. Reinecke. 1984. Proper expression of metabolizable energy in avian energetics. Condor 86:396-400. Monge, C., and J. Whittembury. 1976. High altitude adaptations in the whole animal. Pages 289-308 in J. Bligh, J. L. Cloudsley-Thompson, and A. G. MacDonald, eds. Environmental physiology of animals. John Wiley & Sons, New York. 456pp. Moriarty, D. J. 1976. The adaptive nature of bird flocks: a review. The Biologist 58:67-79. Oosting, H. J. 1956. The study of plant communities. W. H. Freeman and Co., San Francisco, CA. 440pp. Owen, M., and W. A. Cook. 1977. Variations in body weight, wing length and condition of mallard Anas platyrhynchos and their relationship to environmental changes. J. Zool. (Lond.) 183:377-395. �28 Pattenden, R. K., and D. A. Boag. 1989. Effects of body mass on courtship, pairing, and reproduction in captive mallards. Can. J. Zool. 67:495-501. Prince, H. H. 1979. Bioenergetics of postbreeding dabbling ducks. Pages 103-117 in T. A. Bookhout, ed. Waterfowl and wet1ands--an integrated review. Proc. 1977 Symp. Northcent. Sect., Wild1. Soc., Madison, Wis. 152pp. Pulliam, H. R., and G. C. Millikan. 1982. Social organization in the nonreproductive season. Pages 169-197 in.D. S. Farner, J. R. King, and K. C. Parks, eds. Avian Biology, Vol. VI. Academic Press, New York, NY. Ramaley, F. 1942. Vegetation of the San Luis Valley in southern Colorado. Univ. Colo. Studies. Series D. Physical and Biological Sciences. 1:237-279. Reinecke, K. J., and C. W. Shaiffer. 1988. A field test for differences in condition among trapped and shot mallards. J. Wi1d1. Manage. 52:227-232. Ricklefs, R. E. 1974. Energetics of reproduction in birds. Pages 152-297 in R. A. Paynter, Jr., ed. Avian energetics. Nuttall Ornith. Club, Cambridge, Mass. Ringelman, J. K., and M. R. Szymczak. 1985. A physiological condition index for wintering mallards. J. Wildl. Manage. 49:564-568. Robbins, C. T. 1983. Wildlife feeding and nutrition. Academic Press, New York, NY. 343pp. Rubenstein, D. I. 1978. On predation, competition, and the advantages of group living. Pages 205-231 in P. P. G. Bateson and P. H. Klopfer, eds. Perspectives in ethology, vol. 3. Plenum Press, New York, NY. SAS Institute, Inc. 1985. SAS procedures guide for personal computers, version 6 edition. Cary, N.C. 373pp. Shapiro, S. S., and M. B. Wilko 1965. An analysis of variance test for normality (complete samples). Biometrika 52:591-611. Smith, K. G., and H. H. Prince. 1973. The fasting metabolism of subadult mallards acclimatized to low ambient temperatures. Condor 75:330335. Sugden, L. G., W. J. Thurlow, R. D. Harris, and K. Vermeer. 1974. Investigations of mallards overwintering at Calgary, Alberta. Can. Field-Nat. 88:303-311. Szymczak, M. R. 1986. Characteristics of duck populations in the intermountain parks of Colorado. Tech. Publ. 35. 88pp. �29 _____ , and J. F. Corey. 1976. Construction and use of the Salt Plains duck trap in Colorado. Colorado Div. Wildl., Div. Rep. 6. l3pp. Temple, S. A. 1987. Do predators always capture disproportionately from prey populations? substandard individuals Ecology 68:669-674. U.S. Department of Interior. 1979. Final environmental Basin Division, San Luis Valley Project, Alamosa counties. Colorado Bur. Rec. FED 79-37. v.p. statement, Closed and Saguache White, D. C. 1982. Leaf decomposition, macro invertebrate production wintering ecology of mallards in Missouri lowland hardwood wetlands. M. S. Thesis, Univ. Missouri, Columbia. 264pp. Whyte, R. J., G. A. Baldassarre, and E. G. Bolen. 1986. Winter condition of mallards on the southern high plains of Texas. J. Wildl. Manage. 50:52-57. _____ , and E. G. Bolen. 1988. Flight ranges and lipid dynamics mallards wintering on the Southern High Plains of Texas. Ornithol. 59:143-148. and of J. Field �30 CHAPTER RELATIONS 2 AMONG WINTER BODY CONDITION AND SURVIVAL OF MALLARDS WINTERING IN THE SAN LUIS VALLEY, COLORADO Nonhunting mortality of waterfowl is an important component of the compensatory versus additive mortality issue (e.g. Anderson and Burnham 1976; Conroy and Eberhardt 1983; Nichols et al. 1984). Most reports of nonhunting mortality are related to extreme environmental conditions that result in starvation or disease outbreaks (Stout and Cornwell 1976). Other estimates of nonhunting mortality have focused on lead poisoning losses (e.g., Bellrose 1959, Zwank et al. 1985). Regardless of the cause, estimates of nonhunting mortality are difficult to obtain because scavengers remove carcasses quickly and birds often hide before they die, making the carcass more difficult to find (Humburg et al. 1983, Stutzenbaker et al. 1986). Many reported deaths probably reflect mortality that swamped the ability of local scavengers to remove carcasses. Factors which may decrease an individual's survival probability are difficult to quantify. Many waterfowl studies have quantified protein and lipid reserves through the nonbreeding season as a measure of condition (e.g., Baldassarre et al. 1986, Miller 1986, Whyte et al. 1986, Heitmeyer 1988, Whyte and Bolen 1988, Hohman et al. 1988, Serie and Sharp 1989), but few have quantified how body reserves are related to survival or reproduction. Most studies that have attempted to quantify the relation between body condition and survival have focused on relations among condition and hunting mortality. Hepp et a1. (1986) found a negative relationship between body condition and direct recovery probability of autumn-banded mallards (Anas platyrhynchos). Greenwood et a1. (1986) also found hunter-killed birds weighed less than their collected sample. Haramis et al. (1986) reported relations between earlywinter body mass and overwinter and annual survival rates for canvasback (Aythya va1isineria). Krementz et a1. (1989) did not find a relation between late-winter body mass and annual survival rates for American black ducks (Anas rubripes), but the power of their tests was low. Here, we report on winter mortality of marked mallards in a severe winter climate. Our objectives were to (1) document and identify causes of nonhunting mortality, (2) estimate the percent recovery of carcasses, and (3) determine if survival was related to body condition. METHODS Mallard Handling and Marking Mallards on the Monte Vista National Wildlife Refuge (MVNWR) were captured with Salt Plains bait traps (Szymczak and Corey 1976) and cannon nets (Dill and Thornberry 1950) in December 1986 and 1988, January 1987, 1988, and 1989, and February-March 1987, 1988, and 1989. After removal from the trap, mallards were placed in cages lined with straw and transported back to a �31 central processing area. Upon arrival, birds were unloaded from the cages and placed in holding pens lined with straw in a darkened building to dry and to digest grain remaining in their crops. Birds in the holding pens were disturbed when birds were captured for processing or more birds were brought from the traps. This disturbance caused birds to thrash against the fabric sides of the holding pens and the ground, which often frayed their primary tips. Birds remained in the holding pens varying periods of time, from about 2-24 hr. For processing, mallards were removed from the holding cages in groups of 10-20 and carried to another building where data on age, sex, body mass, and wing length were obtained, and a condition index (estimated body fat / estimated fat-free body mass; Ringelman and Szymczak 1985) calculated for each. All mallards were banded with standard U.S. Fish and Wildlife Service leg bands. During 11-18 January 1988 and 12-17 January 1989, most mallards also had monel bands affixed to the shaft of primary feather VIII of both wings. Only leg bands were applied during the other trapping periods. After processing, birds were placed in poultry crates until all crates were full (approximately 120 birds), then birds were transported to within 200 m of open water and released simultaneously. Releases generally occurred during the daylight hours, but some birds (generally around 100 per day) were released during twilight or after dark during the January trapping sessions. Handling Effects To determine possible handling effects, mallards recaptured within 7 days of their initial capture were plotted as a percent of the bird's initial weight. Linear regression was used to test for any relation between duration of time between recapture and differences in initial and recapture body masses. Carcass Collection and Processing In 1987, carcass remains were collected incidentally while conducting other field work. After marking in 1988 and 1989, waterfowl concentration areas and raptor perches on the MVNWR were regularly searched to collect remains of dead waterfowl. Waterfowl concentration areas and eagle perches were searched by walking and/or wading the periphery of the wetland or perch while collecting all carcass remains. Each wing was assumed to represent 1 carcass. When 2 wings were found attached, 1 wing was retained for analyses, the other had the primaries clipped and was transported with the carcasses for disposal by burning. Remains were picked up by the bill, bagged to avoid disease transmission (Friend 1987a), and the location noted. Carcasses were transported to a central location for processing. When possible, species, age, sex, location recovered, and band numbers (if bands were present) were recorded for each carcass. In 1988, every fifth mallard wing, excluding those from banded carcasses, was frozen in airtight bags for later analyses of lipids in the ulna and Pasturella in the radius marrow. One wing from each marked (wing or leg banded) carcass and one wing from each carcass in 1989 was retained for the same analyses. Hutchinson and Owen (1984) suggested that lipids within the ulna are exhausted immediately before a bird succumbs to starvation. To further clarify the use of ulna lipids as an index of malnutrition, I captured 12 mallards, sacrificed the birds after they had been denied food for varying time periods and extracted lipids from the ulna and the carcass (Appendix A). �32 A relation between body lipids and ulna lipids was found where ulna lipids appeared to be depleted when carcass lipids were around 4-5%. Refinement of the technique led to a simple blotter test, wherein an ulna is broken and the contents touched to blotter paper to reveal lipid residue. If a visible lipid· spot remained after being allowed to dry, then the bird had not exhausted its lipid stores (Appendix A). No tests were made to determine if lipids leached from the ulna over time. Wings from 1987, 1988, and 1989, were tested and classified as to the status of lipid reserves. From mid-December 1988 through mid-March 1989, up to 10 complete mallard carcasses were collected weekly and frozen for subsequent necropsies. Carcasses were necropsied and lesions noted (Wobeser 1981). Ulna lipids were used to assess the status of lipid reserves. Impression smears were made of the marrow of a longitudinal slice of the radius and the hepatic parenchymal surface, stained with methylene blue and examined for bipolar-staining bacteria. Cultures were made from the same tissues and examined for growth of Pasturella multocida. Subsequent diagnoses were used to estimate relative importance of the different mortality factors. Percent Carcass Recovery Carcasses with monel bands attached to primary VIII of both wings were planted around wetland roost concentration areas to obtain estimates of the percentage of dead birds being found. Carcasses were placed in locations where dead birds had been previously found. In 1988, 25 carcasses were placed around 3 roost areas searched every·third day by field technicians. In 1989, 65 carcasses were placed around 5 roost areas searched every third day. Only the person planting the carcasses knew when carcasses were planted and their locations. At the end of the field season, percent of the planted carcasses recovered was calculated each year as an estimate of the percent of carcasses recovered. No estimates were made of the number of leg-banded birds recovered. Sex Ratios Aerial photographs of roosting waterfowl were taken 4 February 1988 and 18 January 1989 from an elevation of 150 m. Male and female mallards were counted from selected transparencies in which sex identification was possible. These sex ratio estimates were assumed to represent the population. Sex ratios of carcasses collected were compared with those from the photographs using a Chi-square test to determine if nonhunting mortality was sex-specific. Relations of Body Condition and Survival Body condition of birds found dead within the January-April period of the banding year, reported as recovered during the subsequent hunting season, and recaptures the year after banding were analyzed to identify relations among recovery status and condition using logistic regression in the CATMOD Procedure (SAS Institute Inc. 1987). We used forward, stepwise, univariate selection procedures with a - 0.25 as criteria for inclusion in multivariate models (Hosmer and Lemeshow 1989). Age and sex were bivariate variables included in the screening process because different age/sex mean condition indices may lead to incorrect inferences of relations among body condition and survival. Condition index is treated as a continuous variable. Because some cells contained zero frequencies, maximum-likelihood estimates were obtained for those cells (SAS Institute Inc. 1987). Differences in the likelihood ratio Chi-square of the model with and without the variable of interest are �33 Chi-squares with 1 df, and were used to determine significance of a variable (Hosmer and Lemeshow 1989). RESULTS Handling Effects In 1988, mean body mass of birds recaptured within 7 days of initial capture was less than at initial capture (Fig. 2.1). The difference in mass approached significance while that for condition was not significant (r 3.026, 1,114 df, f - 0.0846 and r - 0.917, 1,114 df, f - 0.3402, for body mass and condition indices, respectively). In 1989, mass and condition were less when recaptu~ed within 7 days, than at initial capture (Fig. 1.2; r - 4.70, 1,307 df, f - 0.0309 and r - 4.91, 1,307 df, f - 0.0274, for body mass and condition indices, respectively). Table 2.1. Numbers of mallard carcasses found and bands collected each field season in the San Luis Valley, Colorado. Year Number of Mallard Carcasses Found Number of Bands Found Percent 1987 229 30 13.1 1988 4,193 201 4.8 1989 1,663 169 10.2 Carcass Collections In 1987, carcasses were collected incidental to other field work, resulting in limited search time; only 229 remains, which included 30 leg bands, were recovered (Table 2.1). In 1988 and 1989, variable effort was devoted to searching for carcasses (Table 2.2). Between 4 January and 1 April 1988 and between 17 January and 1 April 1989, 6,281 carcasses were collected (5,856 mallards), which included 370 banded birds (Table 2.1). Other carcasses were primarily Canada geese (Branta canadensis; 140 carcasses) and northern pintails (Anas acuta; 128 carcasses). �34 CIJ115 CIJ C'U ~ Adult • 110 ~ "0 o 105 c: .- 100 o 95 c: Q) o ~ 90 co C'U 0) ~ ..•....• (23) i (12) o (24) I (6) (5) ~ (19) .J.. (4) Q) CL Immature 850~----~----~2------~3------4~-----5~----~6 Days to Recapture Figure 2.1. Body masses (as % of initial capture mass) of adult and immature male mallards recaptured within 7 days of initial capture in the San Luis Valley, Colorado, January through March 1988. Sample sizes are shown in parentheses with adults above and immatures below the standard deviations. �35 00 115 ~--------------------------------------~ 00 C'O ~ Adult • 110 ~ '"C a CO Immature o 105 ~ -- en l... o 100 (3) 95 ..•...•. c CD o l... (4) 90 f CD CL 85 0 1 234 - (4) 5 6 Days to Recapture Figure 2.2. Body masses (as % of initial capture mass) of adult and immature female mallards recaptured within 7 days of initial capture in the San Luis Valley, Colorado, January through March 1988. Sample sizes are shown in parentheses with adults and immatures below the standard deviations. �36 CIJ 115 CIJ Adult Clj ~ (10) u a co - 105 ~ 100 -en (72) (~5) (34) 95 (1-7) I ~ (26) (10) 1 T I 1 I ~ o • 110 ~ 2 3 l) Immature (2) T 1 • 456 o (1 ) • 7 8 Days to Recapture Figure 2.3. Body masses (as % of initial capture mass) of adult and immature male mallards recaptured within 7 days of initial capture in the San Luis Valley, Colorado, December 1988 through March 1989. Sample sizes are shown in parentheses with adults above and immatures below the standard deviations. �37 en en 115 CO ~ Adult (1) ~ "0 a co - 105 ~ 100 -- (11 ) (7) - 01 \0- 0 ...-c CD o • 110 ~ I 95 I (7) (14) (10) 90 Immature (9) 0 •(7) 0 I (1 ) \0- CD n, 85 0 1 2 3 4 5 6 7 8 Days to Recapture Figure 2.4. Body masses (as % of initial capture mass) of adult and immature female mallards recaptured within 7 days of initial capture in the San Luis Valley, Colorado, December 1988 through March 1989. sizes are shown in parentheses with adults and immatures below the standard deviations. Sample �38 Table 2.2. Hours per week spent searching for waterfowl carcasses and number of carcasses found on MVNWR in 1988 and 1989. Weeks are encoded to start after the January banding effort (11-18 January 1988, and 12-17 January 1989). Week Hours of Search Time 1988 1989 1 2 3 4 5 6 7 8 9 10 11 12 52.0 39.0 27.8 29.8 33.2 33.8 33.5 18.0 12.5 21.5 43.2 20.5 17.0 24.0 3.5 20.0 7.0 0.0 19.5 7.0 11.0 4.5 Number of Carcasses Collected 1989 1988 544 591 383 469 543 399 391 265 169 172 184 93 237 157 45 197 182 3 169 101 95 22 In December 1987, an outbreak of avian cholera on MVNWR prompted premature closure of the refuge to waterfowl hunting. Throughout January and early February 1988, more than 400 carcasses per week were collected (Table 2.2). Although the number of carcasses collected per week declined through late February and early March, this was more a function of reduced search effort and dispersal of birds as wetlands thawed than reduced mortality. Avian cholera was the suspected cause of death in most recorded cases, but some waterfowl died from lead poisoning, starvation, predation, and collisions with wires. Ninety-three mallard carcasses were necropsied. Forty-five of the carcasses had petechiae on the epicard;.um, lesions associated with avian cholera; 8 had penetrating trauma wounds; 4 had exhausted lipid reserves; 2 appeared to have succumbed to lead poisoning; 1 had lesions of both avian cholera and lead poisoning; 1 appeared to have succumbed to aspergillosis; and 20 had no visible lesions. Only 14 cultures of the marrow and 6 hepatic cultures were positive for avian cholera. Four hepatic smears were positive for avian cholera. The strain of avian cholera in the SLV has proven difficult to culture at the National Wildlife Health Center (M. Miller, Colo. Div. Wildl., pers. comm.). In 1988, age and sex was determined from 735 mallard remains; two hundred and five (27.9%) were adult females, 307 (41.8%) were adult males, 106 (14.4%) were immature females, and 117 (15.9%) were immature males. Percentage of males in the carcass collection (57.7%) differed (X2 - 80.8, 1 df, f < 0.0001) from the percentage of males counted in photographs taken 4 February 1988 (79% of 803 mallards counted). In 1989, avian cholera resulted in high waterfowl mortality (Fig. 2.2, and Table 2.2). Of 591 carcasses aged and sexed, 238 (40.3%) were adult males, 96 (16.2%) were immature males, 162 (27.4%) were adult females, and 95 (16.1%) were immature females. Males, which were 56.5% of the carcasses, did not differ from that counted in the aerial photographs (58% of 1,135 mallards counted 18 January 1989; X2 - 0.3, 1 df, f - 0.5607). In 1987, 11 of 85 wings (12.9%) sampled for ulna lipids came from birds �39 that had depleted their lipid reserves. In 1988, more banded than unmarked birds had starved (29 of 201 [14.4%] marked and 31 of 699 [4.4%] unmarked mallards; X2 - 25.1, 1 df, f < 0.0001). Similar analyses in 1989 determined greater percentage of banded than unmarked birds starved (26 of 106 [24.5%] .banded and 42 of 911 [4.6%] unmarked birds; X2 - 60.4, 1 df, P < 0.0001). Percent Carcass a Recovery Bands were recovered from 17 (68%) of the planted carcasses in 1988. (31.5% of 130 wings), representing 23 birds (35.4%) of the birds were recovered. In 1989, 41 wings Relations of Body Condition and Survival Mortality of birds found dead within 3 months of banding was not related to body condition at banding in any year (Table 2.3). Logistic regression identified a relation between condition and recaptures in 1987 (X2 - 4.8, 1 df, f - 0.0293), with adult males in poorer condition and the other age-sex classes being in better condition then most other classification categories (Table 2.3). No condition relation among birds found dead or shot in 1987 was detected (X2 - 0.1, 1 df, f - 0.7913 and X2 - 0.9, 1 df, f - 0.3349, for birds found dead or shot by hunters, respectively). �40 Table 2.3. Mean (SO) condition indices of mallards banded in the San Luis Valley, Colorado in 1987-89 according to status: found dead January -- April of the banding year, direct hunting recovery, recaptured one year later, or not contacted again. Year Age 1987 Adult Sex Not Contacted Found Dead Male 12.8(4.3) N - 495 Female 14.7(5.0) N - 75 Immature Male 11.3(4.3) N - 535 Female 14.0(4.0) N - 248 1988 Adult Male 14.9(4.2) N - 717 Female 15.3(3.9) N - 207 Immature Male 13.2(4.1) N - 498 Female 14.4(4.2) N - 500 1989 Adult Male 12.1(4.2) N - 556 Female 13.0(4.6) N - 292 Immature Male 10.4(4.4) N - 218 Female 10.7(4.7) N - 186 12.7(4.5) N - 10 15.8 N - 1 11.1(6.2) N - 9 14.3(8.4) N - 3 15.7(4.0) N - 70 14.5(5.8) N - 14 13.4(4.2) N - 50 13.8(5.4) N - 35 11.8(4.7) N - 36 11.0(4.6) N - 6 10.0(2.8) N - 22 10.7(4.2 N - 13 Direct Recovery 12.8(5.0) N - 15 19.1(4.2) N - 2 13.3(3.8) N - 12 11.2(9.5) N - 4 15.6(4.6) N - 13 14.1(4.6) N - 3 12.5(6.2) N - 8 12.8(4.3) N - 5 Recapture 11.9(4.2) N - 53 16.7(3.3) N - 5 11.8(3.3) N - 37 15.4(4.9) N - 7 14.5(3.9) N - 83 16.3(2.7) N - 12 13.2(4.0) N - 39 13.7(4.4) N - 14 11.0(3.6) N - 7 13.6(2.3) N - 2 7.6(4.4) N - 3 In 1988 univariate analyses, condition did not meet the a - 0.25 screening criteria for inclusion in a multivariate model, so no multivariate model was tested. Only birds found dead January-April and direct hunting recoveries were available for analysis in 1989, and condition approached significance (X2 - 1.8, 1 df, f - 0.1859 and X2 - 0.3, 1 df, f - 0.5839 for found dead and direct recoveries, respectively). DISCUSSION Differences between percent of marked birds and unmarked birds which starved suggests either unmarked birds included many migrants that did not winter in the SLV or that handling affected survival probabilities of banded birds. Many mallards wintering in the SLV are thought to be residents (Szymczak 1986), but we are unable to estimate numbers of mallards migrating through the SLV to determine if our sample of dead mallards included many migrants. Similarities in condition indices among unmarked birds and shortterm recaptures trapped January through March each year (Chapter 1) suggests condition of marked birds through this period does not differ substantially �4~ from unmarked birds. Handling probably contributed to mortality of some marked birds. Several components of our handling could have affected the survival of marked birds. Some birds flew into fences when released and injured themselves. Other birds were released after dark and they may have been unable to find suitable roosting habitat, and predators may have killed some birds or others succumbed to the low ambient temperatures. Frayed primaries resulting from the birds attempting to escape holding pens may reduce flight efficiency and alter the bird's energy budget such that it may be more likely to succumb to starvation. Logistic regression did not detect a condition effect for banded birds found dead, suggesting that condition and any handling effects are not related. Recovery rates of marked carcasses placed around roost areas were similar to other studies (Humberg et al. 1983, Stutzenbaker et al. 1986). Humberg et al. (1983) reported a recovery rate of 61 (73%) of 79 planted carcasses. Their observations indicated half the carcasses were scavenged within 1 day and the remaining half removed from the area within 4 days. They found recovery of planted carcasses was greatest for visible species, such as snow geese (Chen caerulescens), and least for female dabbling ducks. Stutzenbaker et al. (1986) reported that 50% of the duck carcasses were removed within 1 day. They noted that carcasses restrained in open water persisted longer (11.2 days) than those placed along open (3.8 days) or in vegetative cover (2.6 days). Humberg et al. (1983) suggested shoreline searches cannot be used to provide reliable estimates of total nonhunting mortality. We had more of a controlled situation than just a shoreline search and used our estimates of carcass recovery and the total number of carcasses collected to estimate January through April losses. If carcass recovery in 1988 was 70%, then approximately 6,577 birds died. However, because search effort was variable and carcasses were planted only around roost areas searched, 70% probably overestimates the true recovery rate. The 1989 recovery rate (35%) was probably less than in 1988 because of reduced search effort (Table 2.1). The 35% recovery rate suggests that 4,791 birds died. Because an unknown number of migrants died in the SLV, these estimates cannot be used to directly estimate mortality rates of the wintering population. Mortality in 1988, a year with severe cholera, appeared to have been greater for females than males (57.7% of carcasses collected but 79% of the birds counted in the photographs in 1988 were males). In 1989, no differential mortality related to sex was identified. The 1988 results may have resulted from poor quality photographs which biased counts towards the more easily detectable males. Alternatively, environmental conditions that resulted in the severe avian cholera outbreak may have affected female susceptibility to avian cholera. ~cLandress (1983) found more male than female Ross' geese (Chen rossii) and lesser snow geese died during cholera epizootics, but no differences in species vulnerability was observed. Likewise, Friend (1987b) reported species losses during avian cholera outbreaks were similar to species composition in the area of the outbreak. The lack of any relations among condition at banding and probability of being found dead in January-April may be a result of the large number of avian cholera mortalities. Because susceptibility to avian cholera is not related to body condition (Wobeser 1981, McLandress 1983), and it rarely affects body condition before the bird dies (Wobeser 1981), any relations among body condition and other causes of mortality are relatively insignificant. �42 A threshold response may exist, whereby some minimum body condition is needed for survival, but additional lipid reserves do not increase survival probability substantially. Mallards in the SLV, on average, have lipid reserves to survive at least 2.5 - 4 days without food during the winter (Chapter 1). Food resources in the SLV may be predictable for wintering .ma11ards (Chapter 1), and a mallard may gain little in survival probability by increasing lipid reserves. If lipid reserves are insufficient for a bird to survive 2 days without food, survival probability may decrease substantially. A condition index of 5 - 6 represents about 50 g of lipids for both sexes, which equates to 1.8 days survival time (using a standard metabolic rate (SMR) of 85 kcal / day, energy content of lipids of 9 kca1 / g, and a free-living existence of 3.0 x SMR). In 1987 and 1988, few birds with condition indices of < 6.were reported as hunting mortality or recaptured. Most banded birds that starved had low condition indices (Table 2.4), so many low condition birds may die before the hunting season or trapping periods. Table 2.4. Mean (SD) condition indices at time of capture for banded mallards that died from malnutrition in the San Luis Valley, Colorado. Year Age Adult Sex Female Male Immature Female Male 1988 6.8(12.4) N - 2 12.9(5.0) N - 12 12.2(4.5) N - 9 9.4(12.6) N - 3 1989 4.7(4.5) N - 3 12.5(5.5) N - 10 8.0(0.9) N - 3 10.0(6.9) N - 2 Because annual survival rates of mallards banded preseason in the SLV (63%, 59%, 58%, and 65% for adult and immature males, and adult and immature females, respectively; Szymczak 1986) are similar to or greater than the continental mallard population (63%, 56% and 50% for adult males and females and immature of both sexes combined, respectively; Anderson 1975:22), avian cholera may be compensatory in this population. Low hunting mortality may result in winter mallard populations that exceed carrying capacity for MVNWR, resulting in dense winter concentrations that facilitate cholera transmission. The failure to identify relations among winter body condition and survival may be the result of small sample sizes and mortality resulting from avian cholera. These results do not support or refute the hypothesis that winter or annual survival is directly related to winter body condition. �43 LITERATURE CITED Anderson, D. R. 1975. Population ecology of the mallard. V. Temporal and geographic estimates of survival, recovery, and harvest rates. U.S. Fish Wi1d1. Serv., Resour. Pub1. 125. 110 pp. _____ , and K. P. Burnham. 1976. Population ecology of the mallard: VI. The effect of exploitation on survival. U.S. Fish Wi1d1. Serv., Resour. Pub1. 128. 66pp. Baldassarre, G. A., R. J. Whyte, and E. G. Bolen. 1986. Body weight and carcass composition of nonbreeding green-winged teal on the Southern High Plains of Texas. J. Wi1d1. Manage. 50:420-426. Be11rose, F. C. 1959. Lead poisoning as a mortality factor in waterfowl populations. Illinois Nat. Hist. Surv. Bull. 27:235-288. Conroy, M. J., and R. T. Eberhardt. 1983. Variation in survival and recovery rates on ring-necked ducks. J. Wi1dl. Manage. 47:127-137. Dill, H. H., and W. H. Thornberry. 1950. A cannon projected net trap for capturing waterfowl. J. Wi1dl. Manage. 14:132-137. Friend, M., ed. 1987a. Field guide to wildlife diseases. U.S. Fish Wi1dl. Serv., Resour. Publ. 167. 225 pp . . 1987b. Avian cholera. Pages 69-82 in M. Friend, ed. Field guide to wildlife diseases. Vol. 1. General field procedures and diseases of migratory birds. U.S. Fish Wildl. Servo Resour. Publ. 176. 225pp. Greenwood, H., R. G. Clark, and P. J. Weatherhead. 1986. Condition bias of hunter-shot mallards (Anas platyrhynchos). Can. J. Zool. 64:599-601. Haramis, G. M., J. D. Nichols, K. H. Pollock, and J. E. Hines. 1986. The relationship between body mass and survival of wintering canvasbacks. Auk 103:506-514. Heitmeyer, M. E. 1988. Body composition of female mallards in winter in relation to annual cycle events. Condor 90:669-680. Hepp, G. R., R. J. Blohm, R. E. Reynolds, J. E. Hines, and J. D. Nichols. 1986. Physiological condition of autumn-banded mallards and its relationship to hunting vulnerability. 'J. Wildl. Manage. 50:177-183. Hohman, W. L., T. S. Taylor, and M. W. Weller. 1988. Annual body weight change in ring-necked ducks (Aythya co11aris). Pages 257-269 in M. W. Weller, ed. Waterfowl in winter. Univ. Minnesota Press, Minneapolis. Hosmer, D. W., Jr., and S. Lemeshow. 1989. Applied logistic regression. John Wiley & Sons, New York, NY. 307pp. �44 Humburg, D. D., D. Graber, S. Sheriff, and T. Miller. 1983. Estimating autumn-spring waterfowl nonhunting mortality in north Missouri. Trans. N. Am. Wildl. Nat Res. Conf. 48:241-256. Hutchinson, A. E., and R. B. Owen. 1984. Bone marrow fat in waterfowl. J. Wildl. Manage. 48:585-591. Krementz, D. G., J. E. Hines, P. O. Corr, and R. B. Owen, Jr. 1989. The relationship between body mass and annual survival in American black ducks. Ornis Scand. 20:81-85. McLandress, M. R. 1983. Sex, age, and species differences in disease mortality of ROSS'· and lesser snow geese in California: implications for avian cholera research. Calif. Fish and Game 69:196-206. Miller, M. R. 1986. Northern pintail body condition during wet and dry winters in the Sacramento Valley, California. J. Wildl. Manage. 50:189-198. Nichols, J. D., M. Compensatory evidence and Amer. Wildl. J. Conroy, D. R. Anderson, and K. P. Burnham. 1984. mortality in waterfowl populations: a review of the implications for research and management. Trans. N. and Natur. Resour. Conf. 49:535-554. Ringelman, J. K., and M. R. Szymczak. 1985. A physiological condition index for wintering mallards. J. Wildl. Manage. 49:564-568. SAS Institute Inc. 1987. SAS/STAT guide for personal computers, Version 6 edition. Cary, NC. 1028pp. Serie, J. R., and D. E. Sharp. 1989. Body weight and composition dynamics of fall migrating canvasbacks. J. Wildl. Manage. 53:431441. Stout, I. J., and G. W. Cornwell. 1976. Nonhunting mortality of fledged North American waterfowl. J. Wildl. Manage. 40:681-693. Stutzenbaker, C. D., K. Brown, and D. Lobpries. 1986. Special report: an assessment of the accuracy of documenting waterfowl die-offs in a Texas coastal marsh. pages 88-95 in J. S. Feierabend and A. B. Russell (eds). Lead poisoning in wild waterfowl- a workshop. Proc. of the symposium held 3-4 March 1984, Wichita, KS. Szymczak, M. R. 1986. Characteristics of duck populations in the intermountain parks of Colorado. Colorado Div. Wild1., Tech. Publ. 35. 88pp. �45 _____ , and J. F. Corey. 1976. Construction and use of the Salt Plains duck trap in Colorado. Colorado Div. Wildl., Div. Rep. 6. l3pp. Whyte, R. J., G. A. Baldasssarre, and E. G. Bolen. 1986. Winter condition of mallards of the southern high plains of Texas. J. Wildl. Manage. 50:52-57. _____ , and E. G. Bolen. 1984. Impact of winter stress on mallard body composition. Condor 86:477-482. _____ , and . 1988. Flight ranges and lipid dynamics of mallards wintering on the southern high plains of Texas. J. Field Ornithol. 59:143-148. Wobeser, G. A. 1981. Diseases of wild waterfowl. Plenum Press, New York, NY. 300pp. Zwank, P. J., V. L. Wright, P. M. Shealy, and J. D. Newsom. 1985. Lead toxicosis in waterfowl on two major wintering areas in Louisiana. Wild1. Soc. Bull. 13:17-26. �46 CHAPTER 3 SURVIVAL OF ADULT FEMALE MALLARDS INSTRUMENTED IN THE SAN LUIS VALLEY, COLORADO Declines in the continental mallard (Anas platyrhynchos) population have greatly concerned waterfowl managers in re~ent years. Independent indices indicate a genuine decline in mallard numbers and an uncoupling of the relation between May pond conditions and mallard population size (Johnson and Shaffer 1987). Because survival estimates using band recovery data do not partition mortality into different periods, researchers have often used radiotelemetry to estimate waterfowl survival rates for different periods (e.g., Ringelman and Longcore 1983; Kirby and Cowardin 1986; Bowman and Longcore 1989; Conroy et al. 1989). Telemetry allows a cohort of instrumented birds to be intensively monitored and fates of most birds to be determined. My objectives were to determine January through April survival rates of adult female mallards in relatively "good" and "poor" body condition using radio telemetry. STUDY AREA This study was conducted in the San Luis Valley (SLV) , Colorado. The SLV is a l2,960-km2 intermountain basin in south-central Colorado, bounded by the San Juan Mountains to the west and the Sangre de Cristo Mountains to the east. Soils within the SLV are primarily fine sandy clay with little humus (Enright 1971). As a result of the surrounding mountains and a valley elevation of 2,286 to 2,438 m, the SLV has an arid climate characterized by sort, cool summers and cold dry winters (Lantis 1942). The growing season is 100 to 120 days beginning in mid May, but frost may occur any day of the year (Ramaley 1942). The cool, arid climate and sandy soils have resulted in a 'cold desert' plant association (Oosting 1956). Greasewood (Sarcobatus vermiculatus) and rabbit brush (Ch£Ysothamnus spp.) are the dominant vegetative species on the SLV floor (Enright 1971, Szymczak 1986). In soils that are extremely alkaline, saltgrass (Distichlis stricta) is the only vegetative cover. Sedges (Carex spp.), rushes (Juncus balticus), spikerush (Eleocharis spp.), and saltgrass are common plants along wetland edges (Enright 1971, Szymczak 1986). Cattail (Typha latifolia) and bulrush (Scirpus validus and~. paludosis) are the dominant emergent species (Enright 1971). Although precipitation within the SLV is low, spring run-off from the surrounding mountains provides ample water for irrigation (Hopper et al. 1975). Streams entering the northern part of the SLV percolate under the ground and continue flowing toward the center of the SLV under a layer of clay. This water emerges in central portions of the SLV as artesian wells (Szymczak 1986). Recently, irrigation techniques have changed from flood irrigation to center pivot sprinklers. Water removal by center pivot �47 sprinklers and reduced surface flows have lower the water table and reduced the number of artesian wells recently (Szymczak 1986). The human population in the SLV is low (less than 38,000) and has declined throughout this century; prospects for growth are considered to be low (Mason 1974). Most of the population is concentrated in towns along the Rio Grande and Conejos Rivers (Mason 1974). The local economy is agriculturally based (Mason 1974), with the major crops being irrigated crops, primarily potatoes, barley, vegetables, and hay (Hopper et al. 1975). Livestock production occurs throughout the SLV (Mason 1974). From 1964 through 1980 breeding pair estimates averaged 25,371 pairs, but have declined since primarily because of decreasing habitat (Szymczak 1986). Mallards are the most abundant nester (Szymczak 1986). An average of 18,734 ducks wintered in the SLV (1984-90 average, Colo. Div. Wildl., unpubl. data), with most being mallards wintering on the Monte Vista National Wildlife Refuge (MVNWR). Wintering mallards rest on open water maintained by continuous pumping or artesian flow and forage in nearby grain fields. METHODS We captured mallards wintering on MVNWR with Salt Plains bait.traps (Szymczak and Corey 1976), baited with barley, or cannon-projected nets (Dill and Thornberry 1950), from 11-18 January and 20-22 February 1987 and 11 January through 4 March 1988. Data on age, sex, weight, and wing length were obtained, and a condition index (estimated body fat / estimated fat-free body mass; Ringe1man and Szymczak 1985) calculated for each (See Chapter 1 for Additional Data). We summarized the condition indices of adult females captured the first trapping day of each trapping period, then assigned adult females to 1 of 3 condition classes based upon their condition index relative to the population distribution of the females captured. Subsequently, birds with a condition index in the upper 33% of the range were classified as in "good" condition, the middle 33% were considered "average," and the lower 33% were considered in "poor" condition. In January 1987, 52 adult females in good condition and 51 in poor condition were instrumented with 26 g, back-mounted transmitter packages attached with a harness similar to that described by Dwyer (1972). In February 1987, 18 adult females in good condition and 17 in poor condition were instrumented. In January 1988, 52 adult females in good condition and 51 in poor condition were instrumented. High mortality of instrumented females in 1987 prompted us to anticipate high mortality again in 1988. Initially, we planned to trap weekly and reuse radios collected from dead females by re-applying radios to adult females based upon their condition index relative to the condition index classes used during the 11-18 January trapping period. This protocol resulted in transmitters being re-applied to 23 adult females, 6 in good condition, 1 in average condition, and 16 in poor condition. However, by early February extremely high mortality, difficulties with trapping, and changes in the condition indices of the population made it impractical to reuse radios weekly. Consequently, all radios subsequently collected were reapplied during trapping on 29 February through 4 March. Procedures for determining the relative condition of each bird compared to the population were similar to those used in early January. We instrumented 22 females in good condition, 17 in average, and 24 in poor condition. Standard techniques were used to obtain weekly locations of instrumented ducks from the ground (Cochran 1980:517-518) using vehicle-mounted and hand- �48 1 Good • CO > .> ':::J en Poor 0.8 --{)--. 1 1 0.6 CD > +-' ~ :::J .. 0.4 E :::J o 0.2 a Week Figure 3.1. Cumulative weekly survival rates and standard errors of adult females instrumented in January 1987. �49 held antenna-receiver systems. Birds not found early in the week were located from the air (Gilmer et al. 1981) using a strut-mounted antenna attached to a Cessna 182. All birds located from the air were ground-checked the next day to determine if they were alive or dead, because the radio transmitters did not have mortality sensors. Any birds contacted from the ground that were in unusual locations, did not have attenuating signals, or were in the same location for 2 consecutive weeks were checked visually to determine whether they were alive or dead. The date, estimated date of death, likely cause of death, site description, Universal Transverse Mercator coordinates, and other pertinent comments were recorded for each dead instrumented bird. Carcass remains found with the radio were frozen for further analyses. In 1988, wings from carcasses of instrumented females were analyzed for ulna lipids to determine if the females died from malnutrition, as indicated by ulna lipids of 4-5% (Appendix A). Logistic regression (Hosmer and Lemeshow 1989) was used to determine if the probability of an instrumented females succumbing to malnutrition was related to body condition at instrumentation in 1988. Survival rates of females instrumented in January through 1 April 1987 and January through 26 March 1988 were estimated using the Kaplan-Meier method (Lee 1980, White and Garrott 1990). When an individual cannot be located and classified as alive or dead, the animal is classified as censored. Censored individuals were delete from further analyses. Survival functions were estimated by plotting Kaplan-Meier survival estimates. Comparisons of weekly survival between condition classes were made using 2 x 2 Chi-square tests. All Chi-square tests are one-sided tests assuming survival of birds marked in good condition was greater than survival of poor condition birds. Comparisons between condition class survival of females instrumented in January 1987 and January 1988 were made using logistic regression (Hosmer and Lemeshow 1989). Survival functions of females instrumented in January 1987 and January 1988 were compared using log rank tests (White and Garrott 1990). Because nearly all the mallards wintering in the SLV roost on the MVNWR, counts of mallards on aerial photographs taken on 28 January and 4 February 1988, were used to estimate the survival rate for the period between the 2 photgraphic surveys. This estimate was then compared with the corresponding survival estimate for all instrumented females using a z test to determine if survival rates of instrumented birds differed from the population. RESULTS In 1987, weekly survival rates identified better survival by good condition birds between weeks 3-4 and 7-8 (X2 - 3.2, 1 df, f - 0.0369 and X2 3.7, 1 df, f - 0.0272 for weeks 3-4 and 7-8, respectively). Between weeks 5-6 and 9-10, greater survival rates of good condition birds approached significance (X2 - 1.8, 1 df, f - 0.0890 and X2 - 1.9, 1 df, f - 0.0834 for weeks 5-6 and 9-10, respectively). Logistic regression also identified a relation between condition indices and status (f - 0.0025) and the log rank test identified different survival functions, with better survival for good condition birds (X2 - 4.1, 1 df, f - 0.0422). Kaplan-Meier survival estimates also suggest a relation between condition and survival (Fig. 3.1). In 1988, survival of good condition females was greater between weeks 56 (X2 - 3.3, 1 df, f - 0.0338) and approached significance between weeks 0-1 and 6-7 (X2 - 2.4, 1 df, f - 0.0626 and X2 - 1.9, 1 df, f ~ 0.0838 for weeks 0-1 and 6-7, respectively). Logistic regression (f - 0.2143) and the log rank �50 test (Xl - 1.4, 1 df, f - 0.2432) failed to detect a difference in survival rates or survival functions between the two groups. Kaplan-Meier survival estimates assuming censored birds lived or died does not suggest any relations between condition and survival (Fig. 3.2). Because the two groups did not show differences in survival rates, the samples were pooled for further analyses. The 1 week population survival rate estimated from the aerial photographs, 0.885, did not differ from the pooled estimate for the instrumented females during that week (0.841 ± 0.043, z - 1.023, f - 0.3063) in 1988. This suggests that the instrumented sample was representative of the population during this week. Twelve of 52 wings (23.1%) collected from instrumented females that died in 1988 had exhausted (0-4%) lipid reserves in the ulna (Fig. 3.3). Seven more had reduced (4-8%) lipid reserves in the ulna (Fig. 3.3). Most birds (14 of 18, 78%) with reduced lipid reserves were collected within 3 weeks of instrumentation (Fig. 3.4). Similar percentages of females instrumented in good and poor condition succumbed to malnutrition (Xl - 0.14, 1 df, f 0.7085). Equal numbers of birds instrumented in good and poor condition (6 for each class) were recovered with ulna lipids in the 0-4% category. All birds collected with reduced ulna lipid reserves, 4-8%, were instrumented in poor condition. Recovery patterns for each condition-ulna lipid class were similar (Fig. 3.5) except for the lack of birds instrumented in good condition with 4-8% ulna lipids. Percent of instrumented females dying with exhausted ulna lipids (0-4%) did not differ (Xl - 1.6, 1 df, f - 0.21) from the percent of banded birds found dead with exhausted ulna lipids, (29 of 201, 14.4%, Chapter 2), but the power of this comparison was low (lambda - 2.28, 1 df, B - 0.33, a - 0.05). DISCUSSION Survival was related to condition in 1987 but not in 1988, even though data from instrumented females collected in 1988 suggested that the transmitter package affected weight dynamics of most females (Chapter 4). Analyses of birds banded but not instrumented also revealed a relation between survival and condition in 1987, but not in 1988 (Chapter 2). Carcass collections (Chapter 2) and survival rate estimates of adult females instrumented in the SLV suggest high winter mortality from January through March. Analysis of band recoveries of adult females banded preseason in the SLV produced an survival rate estimate of 0.55 (95% C. I. 0.50 - 0.60; Szymczak 1986:46), substantially higher than 70-day winter survival estimates for our samples of instrumented females (0.3 to 0.4; Figs. 3.1 and 3.2). Both years, survival the rest of the year would have to approach 1.00 to produce an annual survival rate similar to that of females banded in late summer. The preseason mallard population in the SLV may be substantially different from the wintering population, but the distribution of band recoveries suggests many mallards are residents in the SLV. Likewise, these 70-day survival rates are less than mean annual estimates presented in Nichols and Hines (1987:126-151) and Hyland and Gabig (1980) for mallards banded postseason, although annual and geographic variation in survival rate estimates can be high. Weekly mortality was not consistently greater for females instrumented in poor condition. A couple of factors may explain these results. Weekly survival estimates are a function of the number of birds alive at the start of the week. If more good condition birds are at risk, such as in 1987, it is �51 Good ~ 0.8 ._ • Poor \> ,,_ - - B-- :::l (f) CD > ._ ......., -:::l 0.4 (\j --_ E :::l o 0.2 Week Figure 3.2. Cumulative weekly survival rates and standard errors of adult females instrumented in January 1988. �52 15 ~ Q) +-' o Q) 0 o 10 (/J 0), c: .~ "t- O 5 ~ CD .0 E :::l Z 0 0-4 4-8 8-1212_1616-202Q_~424:-2828_3232-3636_4040-44 Percent Llpld in the Ulna Figure 3.3. Distribution of percent lipids in the ulna of 50 wings recovered from instrumented adult female mallards that died in 1988. Ulnas with less than 4-5% lipids are associated with exhaustion of body lipid reserves (starvation). �53 5 "'0 CD +-' as o o •• 0-4 % Ulna Lipid LJ 4-8 % Ulna Lipid 4 en 3 0') ._C ~ *-2 o \.,. CD .0 E 1 ~ z o .• 2. 3 4 5 6 7 week After Instrumentation Figure 3.4. « Chronology of recovery of instrumented birds with low 8%) ulna lipid levels. Figure includes 2 females instrumented in average condition in March, 1988 that were recovered 2 and 3 weeks after instrumentation. �54 5 "'0 "Gooo" Condition 0-4 % Ulna Lipids CD ......, (.) 4 CD 1771 "Good" Condition o o ~ ~ ~ 3 C/) D 0') C ._ 4-8 % Ulna Lipids IIPOOr Condition 0-4 % Ulna Lipids IIPOOrl Condition 4-8 % Ulna Li ids l ~ ,+-2 o ~ CD .c E1 :J Z o 1 2 345 6 7 8 Week of Collection Figure 3.5. Recovery week of wings co1lected with < 8 percent ulna lipids and condition class of the female at instrumentation. �55 possible that more good condition birds may die. Also, if the transmitter package affected survival, poor condition birds may not die at greater rates than good condition females. Although avian cholera was an important cause of mortality of unmarked birds, we saw no instrumented females displaying cholera symptoms. All carcasses recovered that had not been scavenged exhibited a degree of malnutrition (mass loss) or effects of the transmitter package (e.g., the bill being caught in the harness). In both years, most deaths of instrumented females occurred within 4 weeks of instrumentation (Figs. 3.6 and 3.7). Less aerial search time in 1987 resulted in the recovery of some transmitters several weeks after the bird had died. Because most birds that died from malnutrition in 1988 died within 4 weeks of instrumentation, I believe that birds found dead within that period in both years probably died of transmitter-package related reasons (Chapter 4). Although direct causes of death usually could not be identified, the high percent of deaths attributable to malnutrition suggests that many birds may have succumbed to proximate causes of death (e.g., predation), but the ultimate cause of death was associated with the transmitter package. My results suggest that body mass losses identified for instrumented birds (Chapter 4) affected survival of our samples. Although the transmitter package may have affected results, the relation between survival and condition in 1987 but not in 1988 suggests that mallards in better condition in January do have greater survival under certain environmental conditions. Generally, January and February 1987 had a lower prevalence of avian cholera, greater levels of avian predation, milder temperatures and greater snowfall than January and February 1988. The greater snowfall made food unavailable and many instrumented and unmarked mallards were found which had starved. Although no instrumented birds were observed with symptoms of avian cholera, the greater prevalence of avian cholera in 1988 probably did result in some instrumented birds succumbing to avian cholera. Because susceptibility to avian cholera is not related to body condition (Wobeser 1981, McLandress 1983), relations between body condition and other mortality factors may be masked by more females instrumented in good condition dying from avian cholera. Relations between winter body condition and survival need to be examined as the relations among body condition and specific causes of mortality. My results suggest survival is related to winter body condition when starvation and predation are important mortality factors, but not when avian cholera is the prevalent mortality cause. LITERATURE CITED Bowman, T. D., and J. R. Longcore. 1989. Survival and movements of molting male black ducks in Labrador. J. Wildl. Manage. 53:10571061. Cochran, W. W. 1980. Wildlife telemetry. pp. 507-520 in S. P. Schemnitz (ed.). Wildlife management techniques. Fourth ed. Wildlife Soc. Inc., Washington, D. C. Conroy, M. J., G. R. Costanzo, and D. B. Stotts. 1989. Winter survival of female American black ducks on the Atlantic Coast. J. Wildl. Manage. 53:99-109. �56 Dill, H. H., and W. H. Thornberry. 1950. A cannon-projected net trap for capturing waterfowl. J. Wildl. Manage. 14:132-137. Dwyer, T. J. 1972. An adjustable radio package for ducks. Bird-Banding 43:282-284. Enright, C. A. 1971. An analysis of mallard nesting habitat on the Monte Vista National Wildlife Refuge, Colorado. M.S. Thesis, Colorado State University, Fort Collins, co. l13pp. Gilmer, D. S., L. M. Cowardin, R. L. Duval, C. W. Schaiffer, and V. B. Kuech1e. 1981. Procedures for the use of aircraft in wildlife biotelemetry studies. U.S. Fish and Wildl. Serv., Resour. Publ. 140. 19pp. Hopper, R. M., A. D. Geis, J. R. Grieb, and L. Nelson, Jr. 1975. Experimental duck hunting seasons, San Luis Valley, Colorado, 1963-1970. Wildl. Monog. 46:1-68. Hosmer, D. W., and S. Lemeshow. 1989. Applied logistic regression. John Wiley & Sons, New York. 307pp. Hyland, J. M., and P. J. Gabig. 1980. Survival and recovery distribution of central and western Mississippi flyway winter-banded mallards. Nebraska Game Parks Comm., Tech. Ser. 6. l32pp. Johnson, D. H., and T. L. Shaffer. 1987. Are mallards declining in North America? Wildl. Soc. Bull. 15:340-345. Kirby, R. E., and L. M. Cowardin. 1986. Spring and summer survival of female mallards from northcentral Minnesota. J. Wildl. Manage. 50:38-43. Krapu, G. L. 1981. The role of nutrient reserves in mallard reproduction. Auk 98:29-38. Lantis, D. W. 1942. Sage of the San Luis Valley in Colorado. Folks and Fortunes 1:38-40. Lee, E. T. 1980. Statistical methods for survival data analysis. Lifetime Learning Publ., Belmont, CA. 557pp. Mason, J. 1974. San Luis Valley resource area -- social economic profile. Western Interstate Commission for Higher Education, Boulder, CO. 2l9pp. McLandress, M. R. 1983. Sex, age, and species differences in disease mortality of Ross' and lesser snow geese in California: implications for avian cholera research. Calif. Fish and Game 69:196-206. �57 Nichols, J. D., and J. E. Hines. 1987. Population ecology of the mallard. VIII. Winter distribution patterns and survival rates of winter-banded mallards. U.S. Fish Wildl. Serv., Resour. Publ. 162. l54pp. Oosting, H. J. 1956. The study of plant communities. W. H. Freeman and Co., San Francisco, CA. 440pp. Ramaley, F. 1942. Vegetation of the San Luis Valley in southern Colorado. Univ. Colo. Studies. Series D. Physical and Biological Sciences. 1:237-279. Ringelman, J. K., and J. R. Longcore. 1983. Survival of female black ducks, Anas rubripes, during the breeding season. Can. Field-Nat. 97:62-65. _____ , and M. R. Szymczak. 1985. A physiological condition index for wintering mallards. J. Wildl. Manage. 49:564-568. Szymczak, M. R. 1986. Characteristics of duck populations in the intermountain parks of Colorado. Colo. Div. Wildl. Tech. Publ. 35. 88pp. _____ , and J. F. Corey. 1976. Construction and use of the Salt Plains duck trap in Colorado. Colorado Div. Wildl., Div. Rep. 6. 13pp. White, G. C., and R. A. Garrott. 1990. Analysis of wildlife radiotracking data. Academic press, New York, NY. 383pp. Wobeser, G. A. 1981. Diseases of wild waterfowl. Plenum Press, New York, NY. 300pp. �58 10 _ "GOOD" CONDITION h----J "POOR" CONDITION 9 8 (J) U •.... Co 7 6 U m Q) 0 a •.... 5 4 '.. Q) .!J E :J Z 3 ~. 2 .,.. ." " 1 0 1 2 3 4 5 6 7 8 9 10 ·11 12 Weeks After Instrumentation Figure 3.6. Week of recovery of females instrumented in 1987. I considered the week after the last radio was applied during each banding session as the first week. �59 30 25 (/) 0 a: CO 20 0 « w 0 u, 15 0 a: w CO 10 ~ ::J Z 5 o 1 2 3 4 5 6 7 8 9 Weeks After Instrumentation Figure 3.7. Week of recovery of females instrumented in 1988. I considered the week after the last radio was applied during each banding session as the first week. Because we detected no survival differences related to condition, condition classes are combined. �60 CHAPTER 4 EFFECTS OF INSTRUMENTATION ON BODY MASS OF ADULT FEMALE MALLARDS WINTERING IN THE SAN LUIS VALLEY, COLORADO Biotelemetry can provide insights often unattainable using other methods. Numerous studies of waterfowl have used radio telemetry to determine habitat use (e. g. Gilmer et al. 1977, Ringelman et al. 1982, Costanzo et al. 1983, Jorde et al. 1984, Kirby et al. 1985, Thompson and Baldassarre 1988, Morton et al. 1989); survival rates (e. g. Ringelman and Longcore 1983, Kirby and Cowardin 1986); and field-feeding behavior (Jorde et al. 1983). Ideally, behavior of instrumented animals should not be altered by a transmitter or its harness. Yet only a few studies have evaluated potential effects of radio-markers on birds. Greenwood and Sargeant (1973) found that captive mallards (Anas platyrhynchos) and blue-winged teal (~ discors) equipped with back-mounted radiopacks lost more mass and showed skin irritation and behavioral differences when compared with control groups. Perry (1981) noted similar physical and behavioral effects, but no mass loss in canvasbacks (Aythya valisineria). Conversely, Gilmer et al. (1974) was unable to detect effects of breast-mounted transmitters on breeding and social behavior of wild mallards and wood ducks (Aix sponsa). Similarly, Cowardin et al. (1985) and Ringelman et al. (1982) were unable to detect any effects on reproduction attributable to back-mounted transmitters. As part of a study on the relations among winter body condition, survival and reproduction, I applied radios to adult female mallards (Anas platyrhynchos) in January 1987, then noted high mortality of instrumented birds. To investigate sources of this mortality, adult female mallards were again instrumented in 1988 and a sample of these females collected 2-5 weeks after instrumentation. I hypothesized that the high mortality was related to depletion of body reserves caused by behavioral changes associated with instrumentation. The objective of these collections were to determine changes in body mass after instrumentation. STUDY AREA This study was conducted in the San Luis Valley (SLV), in south-central Colorado. The SLV is a 12,960 km2 intermountain basin bounded by the San Juan Mountains to the west and the Sangre de Cristo Mountains to the east. As a result of the surrounding mountains and an elevation of 2,286 to 2,438 m, January temperatures average -4 C, and snow and ice fog are common. An average of 14,700 mallards winter in the SLV (1982-84 average, Colo. Div. Wildl., unpubl. data), with most residing on the Monte Vista National Wildlife Refuge (MVNWR). Wintering mallards rest on open-water areas maintained by continuous pumping or artesian flow, and forage in nearby grain fields. Temperatures below the lower critical temperature for mallards (Chapter 1) and snow cover that reduces food availability make the SLV an �61 energetically stressful environment for wintering mallards. METHODS Instrumentation We captured mallards wintering on MVNWR with Salt Plains bait traps (Szymczak and Corey 1976) or cannon-projected nets (Dill and Thornberry 1950) from 11 January through 4 March 1988. Data on age, sex, weight, and wing length were obtained, and a condition index (Ringelman and Szymczak 1985) calculated for each bird. We summarized the condition indices of adult females captured the first trapping day of each trapping period, then assigned adult females to 1 of 3 condition classes based upon their condition index relative to the population distribution of the adult females captured. Subsequently, birds with a condition index in the upper 33% of the range were classified as in "good" condition, the middle 33% were considered "average," and the lower 33% were considered in "poor" condition. In January 1988, 52 adult females in good condition and 51 in poor condition were instrumented with 26 g back-mounted transmitter packages attached with a harness similar to that described by Dwyer (1972). From 29 February through 4 March, 22 females in good condition, 17 in average, and 24 in poor condition were instrumented. From 18 January through 4 March 1988, mallards were captured periodically and processed similarly to the 11-18 January trapping period. Some mallards captured during earlier trapping efforts were recaptured and differences in mass and condition were calculated and compared with condition indices of the collected samples. Collection In 1988, 10 instrumented females (5 in good and 5 in poor condition at instrumentation) were collected 2-3 and 4-5 weeks after the 11-18 January trapping period, and 2-3 weeks after the March trapping effort. Females were collected opportunistically, because time limitations prevented randomly selecting a particular female to be collected. Additional instrumented females were captured during other field activities during the collection periods and data on body mass recorded and included in analyses of changes in condition. Birds were collected by hand-held dip nets, cannon nets, shotguns or rifles. Collected birds were immediately placed in plastic bags. As soon as possible, body mass, wing length, condition index, and any pertinent comments were recorded before the carcasses were frozen. Carcasses were later thawed and necropsied. Continuous Monitoring In 1989, 5 male and 5 female mallards were instrumented 13 December 1988. Beginning 20 December 1988, 1 male and 1 female per week were continuously monitored from 45 min before sunrise until the bird settled on the roost after sunset. Time of movement initiation and termination were recorded for the instrumented bird relative to important events involving unmarked birds (e.g., movements of large numbers of birds to and away from the site the instrumented bird was using, predator activity, and initiation of field-feeding flights). �62 RESULTS I collected 8 instrumented females in the good and 7 in the poor condition classes during the first collection period, and 5 in each condition class during the second period. Three good, 4 average, and 3 poor condition females instrumented in March were collected. Mean body mass declined in most birds collected 2-3 weeks after instrumentation, but birds appeared to have regained lost mass by weeks 4-5 (Fig. 4.1). During the first collection period, females were collected an average of 15.0 (±2.2) days after instrumentation and mean mass change was -238 g (range 59 to -410 g). Body mass change resulted in an average decline in condition of 15.4 (range 4.4 to -27.8). Body mass and condition of collected females did not differ by condition class at the time of collection (Tables 4.1 and 4.2). In the first collection period, unmarked adult females weighed more than the collected birds (.t - -6.45, 51 df, £ - 0.0001) and were in better condition (.t - -6.51, 51 df, £ - 0.0001). Table 4.1. Mean (SE) body mass (g) and condition index at the time of collection, and changes since initial capture for instrumented female mallards collected 2-3 and 4-5 weeks after instrumentation in 1988 in the San Luis Valley, Colorado. Collection period Januar:£ 2-3 weeks 4-5 weeks Initial condition class Body mass Condition index mass Change in condition Good Poor 752(117) 2.3(8.0) 720(115) 1.8(6.8) -298(86) -18.9(6.8) -170(106) -11.5(7.2) Good Poor 920(63) 13.1(3.3) 799(30) 6.1(1.5) -151(27) -112(23) - 8.3(2.1) - 7.4(1.3) 805(31) 784(29) 817(59) -186(35) -152(30) - 54(31) -12.0(2.3) -10.2(2.6) - 3.2(1.7) Februa:O:-March 2-3 weeks Good Average Poor 7.0(2.3) 5.4(3.3) 7.6(4.0) �63 1,200 1,150 Good 1,100 Average .... ~ .... 0 (1 1,050 Poor - - 8-- en1,000 en Unmarked • ctl 950 ~ 900 ~ "'C a co 850 800 750 700 650 600~~~~'_~~~~~~~~~~~'_'_~~~~ Jan 1 Jan 21 March 1 March 21 Date Figure 4.1. Mean body mass and standard error for females collected 2-3 and 4-5 weeks after instrumentation. Also given are mean body masses at capture for the collected birds and unmarked adult feamles captured during similar time intervals. near the mean. Sample sizes are shown in parenthesis �64 Table 4.2. Comparisons of body masses and condition indices at collection and mass and condition index changes for adult female mallards instrumented in good and poor condition and collected 2-5 weeks after instrumentation in January 1988. Collection period Comparison ,t value df f 2-3 weeks Body mass Condition Mass change Condition change 0.53 0.11 -2.05 -l. 61 13 13 13 13 0.6069 0.9154 0.0611 0.1323 4-5 weeks Body mass Condition Mass change Condition change 3.81 4.31 -2.16 -0.74 8 8 8 8 0.0052 0.0026 0.0632 0.4799 In the second period, females collected 28.3 (±2.6) days after instrumentation lost an average of 132 g (range -71 to -177 g) and declined an average of 8.3 (range -4.4 to -10.1) in condition. Mass and condition declines were similar between the two groups (Tables 4.1 and 4.2). Four unmarked females were captured during the second period. Neither their mean mass of 805 g nor their condition was different from the mean body mass or condition of the collected birds (,t 0.96, 12 df, f - 0.3574 and,t - 0.78, 12 df, f - 0.4491, respectively). Females instrumented in March were collected 18.1 (±4.5) days after instrumentation, lost an average of 133 g (range -32 to -209 g), and condition indices declined an average of 8.6 (range -1.4 to -14.4). Body mass and condition changes differed between good and poor condition females, and between average and poor condition females, but not between good and average condition females (Tables 4.1 and 4.3). �65 Table 4.3. Comparisons of body masses and condition indices at collection and mass and condition index changes for adult female mallards instrumented in good, average and poor condition 29 February-4 March 1988 and collected 2-3 weeks after instrumentation. Condition classes compared Comparison .t value df f Good and Poor Body mass Condition index Mass change Condition change -0.31 -0.24 -4.87 -4.35 4 4 4 4 0.7702 0.8230 0.0082 0.0122 Good and Average Body mass Condition index Mass change Condition change -0.91 -0.73 1.38 0.81 5 5 5 5 0.4028 0.5001 0.2257 0.4541 Average and Poor Body mass Condition index Mass change Condition change -0.98 -0.83 -4.18 -3.47 5 5 5 5 0.3708 0.4455 0.0087 0.0179 High mortality rates among mallards instrumented in December 1988 only allowed for 4 continuous monitoring sessions. Most deaths occurred 2-3 weeks after instrumentation. Instrumented birds were among the last birds to leave roosts on field-feeding flights in the evening, and among the first to return to roost areas. Consequently, instrumented birds were away from the roost for only 48.5 (± 15.2) min whereas the entire flock field-feeding flight lasted 133.3 (±40.0) min. We recorded no instances of large groups of mallards returning to roost areas after having initiating field-feeding and then leaving again for another flight. DISCUSSION Without a larger sample of females that were banded concurrently during the time radios were applied and then recaptured when instrumented birds were collected, it is impossible to determine if measured mass loss indicates: (1) a handling effect from the banding process; (2) a response to the radio package; or (3) a general reduction in mass of adult females during this period. Comparative mass losses of recaptured banded birds suggest that handling effects were not alone responsible for the mass losses observed among instrumented females (Chapter 1). Also, we cannot determine the relation of observed mass loss to high mortality rates of instrumented females (Chapter 3), because other winter survival estimates (Chapter 2) suggest high winter mortality within this mallard population. Effects of transmitter packages on bird behavior and survival range from little to no effect (e.g., Gilmer et al. 1974, Herzog 1979, Hines and Zwickel 1985, Wanless et al. 1988, Sedinger et al. 1990) to reduced survival (Warner and Etter 1983, Marks and Marks 1987), and include body mass loss and behavioral effects (Greenwood and Sargeant 1973), abnormal behavior (Perry 1981), and increased energy expenditure during flight (Gessaman and Nagy �66 1988). This wide range of reported avian responses to transmitter packages may occur because: (1) sampling has been insufficient to detect effects; (2) instrumentation may affect certain species more than others; or (3) species may be more sensitive to instrumentation at certain times of the year. Although instrumented mallards participated in field-feeding flights in 1989, foraging time was less than the time required to meet estimated standard metabolic rate needs (Chapter 1). Because standard metabolic rate does not include energy required for activity, instrumented females were in a negative energy balance that resulted in the observed mass loss. Morton et al. (1989) found that an unexpected number of American black duck (Anas rubripes) females instrumented in the winter remained on their study area after they should have migrated. They could not rule out the possibility of the radio package ~ffecting behavior, but suggested that because flight behavior seemed normal, it was more likely that resident birds had been instrumented. These birds may also have been affected in ways that could not ·be detected simply by evaluating flight behavior. Based only on this criterion, we would also have concluded that radio packages had no effect because instrumented mallards participated in field-feeding bouts. Sedinger et al. (1990) found no increase in energy expenditure of Pacific black brant (Branta bernicla ni~ricans) affixed with radio transmitters housed in cages that allowed little activity, whereas Gessaman and Nagy (1988) found homing pigeons (Columbia livia) flying with transmitter packages increased CO2 production from 41 to 52%. Results from these studies suggests transmitter packages affect flight, but not maintenance energetics. Transmitter packages probably increase mallard energy expenditure during flight in a way similar to pigeons. SLV mallards already have low body masses (Chapter 1), and may be reluctant to increase energy expenditure in response to radio transmitters. Most studies have not been designed to identify subtle behavioral effects that may influence results, or tracking intensity has not been sufficient to determine if mortality and migration (or lack of normal migration) occurs normally. One approach (i.e., Derleth and Sepik 1990) is to exclude birds obviously affected by the transmitter packages (i.e. birds which die soon after instrumentation) but assume surviving birds behaved normally, which may not be the case. Experimental design should allow for evaluation of possible adverse effects of the transmitter package itself. Results from my study suggest that application of transmitters during energetically stressful times may alter body mass dynamics of the instrumented sample of birds. �67 LITERATURE CITED Costanzo, G. R., T. T. Fendley, and J. R. Sweeney. 1983. Winter movements and habitat use by wood ducks in South Carolina. Proc. Annu. Conf. Southeast. Assoc. Fish and Wildl. Agencies 37:67-78. Cowardin, L. M., D. S. Gilmer, and C. W. Shaiffer. 1985. Mallard recruitment in the agricultural environment of North Dakota. Wildl. Monog. 92. 37pp. Derleth, E. L., and G. F. Sepik. 1990. Summer-fall survival of American woodcock in Maine. J. Wildl. Manage. 54:97-106. Dill, H. H., and W. H. Thornberry. 1950. A cannon projected net trap for capturing waterfowl. J. Wildl. Manage. 14:132-137. Dwyer, T. J. 1972. An adjustable radio package for ducks. Bird-Banding 43:282-284. Gessaman, J. A., and K. A. Nagy. 1988. Transmitter loads affect the flight speed and metabolism of homing pigeons. Condor 90:662-668. _Gilmer, D. S., I. J. Ball, L. M. Cowardin, and J. H. Riechmann. 1974. Effects of radio packages on wild ducks. J. Wildl. Manage. 38:243252. _____ , R. E. Kirby, I. J. Ball, and J. H. Riechmann. 1977. Post-breeding activities of mallards and wood ducks in north-central Minnesota. J. Wildl. Manage. 41:345-359. Greenwood, R. J., and A. B. Sargeant. 1973. Influence of radio packs on captive mallards and blue-winged teal. J. Wildl. Manage. 37:3-9. Herzog, P. W. 1979. Effects of radio-marking on behavior, movements, and survival of spruce grouse. J. Wildl. Manage. 43:316-323. Hines, J. E., and F. C. Zwickel. 1985. Influence of radio packages on young blue grouse. J. Wildl. Manage. 49:1050-1054. Jorde, D. G., G. L. Krapu, and R. D. Crawford. 1983. Feeding ecology of mallards wintering in Nebraska. J. Wildl. Manage. 47:1044-1053. Jorde, D. G., G. L. Krapu, R. D. Crawford, and M. A. Hay. 1984. Effects of weather on habitat selection and behavior of mallards wintering in Nebraska. Condor 86:258-265. Kirby, R. E., J. H. Riechmann, and L. M. Cowardin. 1985. Home range and habitat use of forest-dwelling mallards in Minnesota. Wilson Bull. 97:215-219. �68 Kirby, R. E., and L. M. Cowardin. 1986. Spring and summer survival of female mallards from northcentral Minnesota. J. Wildl. Manage. 50:38-43. Marks, J. S., and V. S. Marks. 1987. Influence of radio collars on survival of sharp-tailed grouse. J. Wi1dl. Manage. 51:468-471. Morton, J. M., R. L. Kirkpatrick, M. R. Vaughan, and D. F. Stauffer. 1989. Habitat use and movements of American black ducks in winter. J. Wildl. Manage. 53:390-400. Perry, M. C. 1981. Abnormal behavior of canvasbacks equipped with radio transmitters: J. Wild1. Manage. 45:786-789. Ringe1man, J. K., J. R. Longcore, and R. B. Owen, Jr. 1982. Breeding habitat selection and home range of radio-marked black ducks (Anas rubripes) in Maine. Can. J. Zool. 60:241-248. _____ , and . 1983. Survival of female black ducks, Anas rubripes, during the breeding season. Can. Field-Nat. 97:62-65. _____ , and M. R. Szymczak. 1985. A physiological condition index for wintering mallards. J. Wild1. Manage. 49:564-568. Sedinger, J. S., R. G. White, and W. E. Hauer. 1990. Effects of carrying radio transmitters on energy expenditure of Pacific black brant. J. Wi1dl. Manage. 54:42-45. Szymczak, M. R., and J. F. Corey. 1976. Construction and use of the Salt Plains duck trap in Colorado. Colorado Div. Wild1., Div. Rep. 6. 13pp. Thompson, J. D., and G. A. Baldassarre. 1988. Postbreeding habitat preference of wood ducks in northern Alabama. J. Wildl. Manage. 52:80-85. Wanless, S., M. P. Harris, and J. A. Morris. 1988. The effect of radio transmitters on the behavior of common murres and razorbills during chick rearing. Condor 90:816-823. Warner, R. E., and S. L. Etter. 1983. Reproduction and survival of radio-marked hen ring-necked pheasants in Illinois. J. Wildl. Manage. 47:369-375. Prepared by: ~.{'i..!l::f>7F~ Wildlife Researcher C �69 APPENDIX A USE OF ULNA LIPIDS TO IDENTIFY STARVATION IN MALLARDS Condition indices are important tools for monitoring nutrient reserves in wild animals (Kirkpatrick 1980). Cheatum (1949) first described the use of bone marrow fat to indicate starvation in deer. Hutchinson and Owen (1984) examined lipid storage in medullary bone of American black ducks (Anas rubripes), common eiders (Somateria mo11issima), and brant (Branta bernic1a) and the possibility that medullary lipid levels could be used as a condition indicator. They reported that medullary lipids were mobilized disproportionately to other lipid depots, and were one of the last depots depleted before death. Their results suggest that medullary lipid levels may serve as an indicator of death resulting from malnutrition. The objectives of this study were to confirm that depletion of medullary lipid levels in the ulna of mallards (Anas p1atyrhynchos) is indicative of death resulting from malnutrition, and to develop a test that could identify individuals dying·of malnutrition without extracting medullary lipids. METHODS Twelve mallards (1 adult female, 3 adult males, 7 immature males, and 1 immature female) were trapped 18 March 1987. Three birds were euthanized immediately using CO2 in an airtight box. The remaining birds were held in captivity with water, but no food, for varying periods before being euthanized. Carcasses were plucked and frozen in plastic bags for storage. Later, carcasses were thawed and the bill, feet below the proximal end of the tarsus, and gut contents were removed. Before grinding, both ulnas were excised from the wings, cleaned of adhering tissue, and frozen in plastic bags for later lipid extraction. The partly refrozen carcasses were weighed and ground three times through the 9-mm plate of a commercial meat grinder. The grinder was thoroughly cleaned in hot water between each samp1e.After partial refreezing, the homogenate was passed three more times through a 3.5-mm grinding plate. During the final grinding, two subsamp1es of about 20 g were selected and placed into preweighed 25- x 100-mm cellulose extraction thimbles. Samples in thimbles were weighed (0.0001 g) and then dried in a convection oven at 100 C to a constant weight (48 h) to determine percent carcass water. After drying, fat was extracted for 6-8 h using petroleum ether in a Soxh1et extraction apparatus. Ulnas were cracked open, placed in preweighed extraction thimbles and processed similarly to the carcass homogenate samples. Percent fat in the ulna and percent total body fat, on a dry weight basis, were plotted. To reduce time and cost of exam~n~ng a large sample of wings collected from dead mallards, a simpler test was examined. A random sample of 50 ulnas were cracked open, then the marrow touched to a clean piece of blotter paper. The resulting spot was allowed to dry and then was examined for residual fat. �70 The resulting blots indicated if a bird had starved. The cracked ulnas were placed in preweighed extraction thimbles; lipids extracted in a manner similar to the extraction procedure for the ulnas from the complete carcasses. Three observers repeated classification of the resulting blots three times. Classifications were then compared with lipid extraction results to determine classification error rate. RESULTS Body masses ranged from 565 to 1022 g, and percent body fat from 0.7 to 26.6% dry weight. Relatively constant ulna lipid levels were maintained to a critical range, around 5% total body fat, after which ulna lipid levels declined (Fig. A.l). To simplify examination of a larger sample, 2 of the 50 ulnas used in the blotting paper spot tests came from birds that had very low lipid levels in the ulna and were classified as having succumbed to depletion of body lipids. No classification errors were made in any trial; birds classified as starved had depleted body lipids, and those classified as not starved did not deplete reserves. DISCUSSION Determining whether a mallard had died with depleted lipid reserves allows mortality to be partitioned into causes that affect physical condition and those that do not affect condition. However, this technique does not allow the ultimate cause of mortality to be determined. Several mortality causes, such as malnutrition and plumbism, result in depletion of lipid reserves. The technique of cracking an ulna and touching it to blotter paper provides a quick and simple test to determine if a bird has exhausted its lipid reserves. Using this technique to determine percentage of birds dying from starvation, we were able to sample more than 1,000 wings in less than a week. Although ulna lipids have been shown to be related to total body lipids in other waterfowl species, we suggest that before sampling wings to determine starvation percentages in other species, these relations be verified for the species in question. Further work may be able to combine other measures, such as lead levels in the humerus or staining for Pasturella mu1tocida in the radius, to allow ultimate causes of mortality to be identified. By identifying ultimate mortality causes, managers will be able to manipulate conditions that are indirect causes. For example, although identification of predation as a proximate cause of death may be easy, individuals vulnerable to predators may have died because some ultimate factor altered their physiology, behavior, or habitat such that their survival probability is decreased. �71 30 * 25 - * ~ C"U * LL C"U 20 c: :J ~ * :I< - * ;5 - c: CD o ~ ;0 - CD (L * 5 0 0 " ;0 5 ;5 20 25 Percent Carcass Fat Figure A.I. Relation between total body lipids and lipids extracted from the ulna of 12 mallards. 30 �72 LITERATURE CITED Cheatum, E. L. 1949. Bone marrow as an index of malnutrition in deer. New York State Conserv. 3:19-22. Hutchinson, A. E., and R. B. Owen. 1984. Bone marrow fat in waterfowl. J. Wildl. Manage. 48:585-591. Kirkpatrick, R. L. 1980. Physiological indices in wildlife management. pp 99-112 IN S. D. Schemnitz (ed.). Wildlife management techniques manual, 4th ed. The Wildlife Soc., Washington, D.C. �73 APPENDIX B USE OF BANDS ON PRIMARY FEATHERS TO IDENTIFY MORTALITY OF MARKED MALLARDS Avian researchers have marked birds with leg bands since the turn of the century (Marion and Shamis 1977). Unfortunately, leg bands are often not recovered from birds killed by predators or from scavenged carcasses. Such carcasses are often represented just by the wings, which mayor may not be attached by the coracoids. In our study of wintering mallards (Anas p1atyrhynchos), loss of leg bands to predators or scavengers probably reduced the information we obtained from our banded sample the first year. To increase our sample of marked carcasses recovered, we developed a technique to mark a primary on each wing with a numbered monel band. METHODS Mallards captured in the San Luis Valley, Colorado, in January 1988 and January 1989 were captured in Salt Plains bait traps (Szymczak and Corey 1976) and cannon nets (Dill and Thornberry 1950). Data on age sex, body mass, and wing length were obtained for all birds, and a condition index (estimated body fat / estimated fat-free body mass; Ringe1man and Szymczak 1985) calculated for each. All birds were marked with standard USFWS leg bands, and most marked with similarly numbered size 4 monel bands (National Band and Tag Co. , Newport, Kentucky) placed on the rachis of primary VIII on each wing. To determine rates of wing band loss, mallards subsequently recaptured were examined for retention of both wing bands. To restrain the bird for attachment of the bands, a 50 cm x 50 cm piece of 0.8 mm p1exig1ass had 4 pairs of holes drilled as shown in Figure B.1. Cord was looped through the holes with 1 end secured by a knot and the other by a sliding catch. A mallard was secured by placing the head through the top loop and securing the loop snugly around the neck. The wings were individually pulled through a loop and the cord secured next to the body. The bottom loop could be placed over the abdomen for additional restraint if necessary. Epoxy was attached to the bottom of the p1exig1ass, or edges were trimmed, to assure all restraining boards were equal mass. The bird was then weighed on the restraining board to reduce handling. RESULTS In 1988 and 1989, 1,700 and 2,061 wing bands were placed on wintering mallards (Table B.1). Of the 161 mortalities of banded birds recorded in 1988, 96 (59.6%) were identified only by the recovery of at least 1 wing band from the bird. In 1989, 136 mortalities of banded birds were recorded, of which 107 (78.7%) were identified from wing band recovery. In both years, use of wing bands increased the recovery of marked birds. �74 30CM 3CM c5c9 0 ~$.SCM -, 13 eM 3OCM 0 7CM ~3CM 0 SCM 9CM Figure B.l. Diagram showing hole locations in the plexiglass panel used for restraining mallards. �75 Table B.l. Numbers of wing bands placed on wintering mallards in 1988 and 1989 in the San Luis Valley, Colorado. Number Win& Banded Age Adult Adult Immature Immature Sex Female Male Female Male 1988 1989 236 683 320 461 414 988 274 385 Forty-six mallards were recaptured and examined for wing band retention in 1989. Only 2 (4%) of the wing banded birds (1 adult and 1 immature male) had lost both wing bands (Table B.2). Six (13%) had lost 1 wing band (Table B.2). Although sample sizes are small, band loss appears to be greatest for immature females and least for adult males (Table B.2). Table B.2. Number of wing bands retained by 46 mallards recaptured in the San Luis Valley, Colorado, in 1989. All birds initially had 1 band attached to primary VIII on each wing. Age Sex Number of Wing Bands on Recaptured Mallards 0 2 1 Adult Adult Immature Immature Females Male Female Male 0 1 0 1 1 2 2 1 4 24 2 8 DISCUSSION We found the use of monel bands on primary VIII to be an effective technique to increase the recovery of banded mallards. Wing bands provided an individual marker that did not present any visible cues that might affect survival rates. Scavengers often remove leg bands from a carcass, which results in small recovery samples in studies focusing on non-hunting waterfowl mortality. By using wing bands, we were able to more than double our recovery samples. Additional uses included using wing bands to measure the number of mallard carcasses that were planted by one researcher and recovered by the people searching for waterfowl carcasses. Use of wing bands allowed the number of carcasses represented by single wings recovered to be estimated. Loss of wing bands probably reflects the interaction of 2 factors: diameter of the primary rachis and variability in who applied the wing band. Diameter of the rachis of primary VIII tends to be less in females than males, and smaller in immatures than adults. Consequently, loss in immature females should be greatest, as we observed. Additionally, the person applying the bands may not test the band by attempting to move the band on the rachis. If the band moved, it could be tightened before the bird was released. A potential problem with the use of wing bands involved applying too �76 much pressure during application such that the band crushed the rachis of the primary. When this occurs, the primary may be broken soon after release. We believe this rarely happened in our sample since no birds were recaptured with primary VIII broken. Use of wing bands provides researchers studying non-hunting mortality in waterfowl a technique to increase sample sizes. Application time is only a couple of minutes, and the individualized markers appear to have little effect upon the bird. LITERATURE CITED Dill, H. H., and W. H. Thornberry. 1950. A cannon projected net trap for capturing waterfowl. J. Wildl. Manage. 14:132-137. Marion, W. R., and J. D. Shamis. 1977. An annotated bibliography of bird marking techniques. Bird-Banding 48:42-61. Szymczak, M. R., and J. F. Corey. 1976. Construction and use of the Salt Plains duck trap in Colorado. Colorado Div. Wildl., Div. Rep. 6. l3pp. �77 APPENDIX C FACTORS INFLUENCING SIZE OF THE MALLARD POPULATION WINTERING IN THE SAN LUIS VALLEY, COLORADO Nichols et al. (1983) reported that mallards (Anas platyrhynchos) wintering in the Mississippi Alluvial Valley were recovered further south during cold winters, and more immatures and adult females were recovered in the Mississippi Alluvial Valley in wet winters than dry winter. Adult males did not show any response in wet and dry years. They concluded that temperatures, precipitation, and population size did affect winter distributions. Our objective in this study was to identify whether winter temperatures, precipitation and size of the breeding population are important factors determining the number of mallards wintering in the San Luis Valley, Colorado. STUDY AREA This study was conducted in the San Luis Valley (SLV), Colorado. The SLV is a 12,960-km2 intermountain basin in south-central Colorado, bounded by the San Juan Mountains to the west and the Sangre de Cristo Mountains to the east. As a result of the surrounding mountains and a valley elevation of 2,286 to 2,438 m, the SLV has an arid climate characterized by short, cool summers and cold dry winters (Lantis 1942). From 1964 through 1980, breeding pair estimates averaged 25,371 pairs, but have declined since then primarily because of decreasing habitat (Szymczak 1986). Mallards are the most abundant nester (Szymczak 1986). An average of 18,734 ducks wintered in the SLV (1984-90 average, Colo. Div. Wildl., unpubl. data); most are mallards wintering on the Monte Vista National Wildlife Refuge (MVNWR). Wintering mallards rest on open water maintained by pumping or artesian flow, and forage in nearby grain fields. METHODS To identify factors determining the number of mallards wintering in the SLV, winter survey and breeding mallard popUlation estimates in the SLV from 1964 through 1988 were obtained from the Colorado Division of Wildlife (unpubl. data). National Oceanic and Atmospheric Administration weather summaries for the Alamosa Airport reporting station were examined for mean monthly temperatures and total precipitation for November, December, and January for years corresponding to those that had winter inventory data available. Linear regression was used to identify relations among winter population size and the other variables. Linear regression was used to compare estimated breeding populations with the estimated wintering population the previous January to examine a relation between wintering population size and the subsequent breeding population. Relations between dependent variables were e~amined with the Pearson product-moment correlation. �78 RESULTS The number of mallards wintering in the SLV was influenced by size of the breeding population (F - 22.98, 1,18 df, f - 0.0002), December temperature (F - 9.12, 1,18 df, f - 0.0077), total precipitation in December (F - 8.33, 1,18 df, f - 0.0102), and an interaction between breeding population size and December temperature (F - 5.73, 1,18 df, f - 0.0284). Because year and breeding population size were strongly correlated (r - -0.828, f - 0.0001), the relation between year and winter population size that was first identified (F - 6.02, 1,18 df, f - 0.0397) reflects the change in breeding population rather than a relation between winter population and year. December temperature and precipitation were negatively correlated (r - -0.652, f - 0.0004). Winter population size was positively correlated with December temperature (r - 0.128, f - 0.5428) and negatively correlated with December precipitation (r - -0.224, f 0.2822). The breeding population in a year is related to size of the population the previous January (F - 14.08, 18 df, f - 0.0016). DISCUSSION The positive relation between breeding and wintering population sizes is not surprising considering many mallards are thought to be residents of Colorado (Szymczak 1986). The relations between winter population estimates and December temperatures and precipitation suggest more mallards winter in the SLV in winters that begin with warm, dry conditions. Mallards may be assessing food availability through December, and if environmental conditions reduce food availability, may then migrate from the SLV. Because counts are made in January, the lack of any relation with January weather variables may reflect that counts generally occurred before many birds could respond to severe weather. Although systematic counts were not taken during our study, our belief is chat no noticeable exodus of mallards from the SLV occurred during periods of severe weather in January. We believe that mallards will respond to severe environmental conditions, probably by responding to food availability by migrating in December, but severe conditions later in the winter do not result in migration of many mallards from the SLV. LITERATURE CITED Lantis, D. W. 1942. Sage of the San Luis Valley in Colorado. Folks and Fortunes 1:38-40. Nichols, J. D., K. J. Reinecke, and J. E. Hines. 1983. Factors affecting the distribution of mallards wintering in the Mississippi Alluvial Valley. Auk 100:932-946. Szymczak, M. R. 1986. Characteristics of duck populations in the intermountain parks of Colorado. Colorado Div. Wildl., Tech. Publ. 35. 88pp. �79 APPENDIX D NESTING CHRONOLOGY OF MALLARDS IN THE SAN LUIS VALLEY, COLORADO Several factors have been related to waterfowl nest initiation dates. Sowls (1955) reported a relation between environmental temperatures and nest initiation dates, but noted several inconsistencies in the data. Other factors that influence nest initiation dates are spring water conditions (Krapu et al. 1983), geographic origin (Batt and Prince 1978, 1979), diet quality (Eldridge and Krapu 1988), and winter body mass (Pattenden and Boag 1989). Our objective in this study was to determine the date of hatch for mallards nesting in the San Luis Valley, Colorado. STUDY AREA This study was conducted in the San Luis Valley (SLV), in south-central Colorado. The SLV is a 12,960 km2 intermountain basin, bounded by the San Juan Mountains to the west and the Sangre de Cristo Mountains to the east. As a result of the surrounding mountains and a valley elevation of 2,286 to 2,438 m, the SLV has an arid climate characterized by short, cool summers and cold dry winters (Lantis 1942). From 1964 through 1980, breeding pair estimates averaged 25,371 pairs, but have declined since then, primarily because of decreasing habitat (Szymczak 1986). Mallards are the most abundant nester (Szymczak 1986). An average of 18,734 ducks wintered in the SLV (1984-90 average, Colo. Div. Wildl., unpubl. data); most are mallards wintering on the Monte Vista National Wildlife Refuge (MVNWR). Wintering mallards rest on open water maintained by pumping or artesian flow, and forage in nearby grain fields. METHODS Nesting chronology of mallards was monitored using pair and brood counts. In 1987, brood counts were made whenever broods were encountered. A survey route was established on MVNWR and driven weekly from 19 April through 15 June 1988, and 22 April through 14 June 1989. Male mallards encountered were classified as paired (with female), lone male (single isolated drake without a visible associated female), or grouped (2-5 associated males in 1987 and 1988, 2-4 associated males in 1989). In 1989, groups of 5 males were not considered grouped to conform with standard operating procedures for breeding pair counts (H. Funk, pers. comm.). Broods encountered along the route or at any other time were recorded as to species, number, and age (Gollop and Marshall 1954). Brood ages were used to back-date to the estimated hatching date. �80 RESULTS Throughout the nesting period, many males appear paired (Figs. 0.1 and 0.2). In two of the three years, estimated hatch dates of mallard broods reflected the drawn-out nesting period suggested by the pair counts (Figs. 0.3, 0.4, and 0.5). In 1988, the hatching curve showed a peak in hatch the week of 1 June (Fig. 0.4). In 1987 and 1989, the hatch peak covered several weeks from mid-May through mid-June (Figs. 0.3 and 0.5). DISCUSSION The pair counts and hatch curves suggest that nest initiation is prolonged in the SLV. Whether this pattern results from the low winter body mass or other environmental factors can not be determined from these data. Pattenden and Boag (1989) reported that low body mass in winter had a greater influence on laying date than low body mass in spring. The extended period of nest initiation may reflect variability in the low body masses and the time required for a female to achieve the body condition necessary for a reproductive attempt. We do not know how rapidly a female can increase her body condition when environmental conditions improve. Heitmeyer (1988) suggested timing of events (e.g., prebasic molt and pairing) in the annual cycle of female mallards are influenced by a female's body condition, and the females that complete these events early may realize reproductive advantages. Unlike mallards wintering in Missouri, mallards wintering in the SLV had not initiated prebasic molt in January 1988 (C. W. Jeske, unpubl. data). This suggests mallards wintering in the SLV are not as advanced in their reproductive cycle as mallards in Missouri. Because most mallards wintering in the SLV do not migrate, they delay molt until after severe winter conditions have passed and molt while other wintering populations are migrating. This delay also may influence the initiation of nesting. More information on the reproductive chronology of this population is needed. We were not able to determine if winter body condition is related to subsequent reproduction. Consequently, this remains an important question in determining if the low body conditions measured in SLV mallards are related to the unusual nesting chronology in the SLV. The prolonged nesting chronology noted may reflect different reproductive efforts by immature and adult females, or it may reflect different efforts by residents and migrants. How age and residency influence a female's reproductive effort need to be explored. �81 260 ~--~--------------------------------------. 240 220 U 200 CD 180 +-' C 160 ::J a (J en 140 120 CD 100 C\j 80 ~ 60 40 20 o 4/19 4/26 5/10 5/17 5/24 6/3 6/8 6/15 Date of Count Figure 0.1. Number of male mallards counted from a census route on MVNWR and classified as lone or paired from mid-April through mid-June 1988. �82 260 240 _ Lone Male 220 ~ Pair Grouped Males r2Z3 '"C 200 Q) 180 ~ C 160 ::J a (J 140 120 CIJ 100 C'U 80 Q) ~ 60 40 20 o 4/22 4/30 5/6 5/14 5/22 5/30 6/8 6/14 Date of Count Figure 0.2. Number of male mallards counted from a census route on MVNWR and classified as paired, lone, or grouped from mid-April through mid-June, 1989. �83 40 CIJ -0 30 a a ~ CO '+- 020 MAY 15 JUNE 1 JUNE 15 JULY 1 JULY 15 Week Figure 0.3. Estimated hatch dates of mallard broods encountered in the SLV, Colorado, 1987. �84 40 CIJ "'C 30 a a \"". co lot- a 20 o MAY 15 JUNE 1 JUNE 15 JULY 1 JULY 15 Week Figure 0.4. Estimated hatch dates of mallard broods encountered in the SLV, Colorado, 1988. �85 CIJ U o 020 1- CO '+- o 1- CD ..c E 10 :::J Z o MAY 1 MAY is JUNE 1 JUNEiS JULY 1 JULY1S Week Figure 0.5. Estimated hatch dates of mallard broods encountered in the SLV, Colorado, 1989. �86 LITERATURE CITED Batt, B. D. J., and H. H. Prince. 1978. Some reproductive parameters of mallards in relation to age, captivity, and geographic origin. J. Wildl. Manage. 42:834-842. , and . 1979. Laying dates, clutch size and egg weight of --------- captive mallards. Condor 81:35-41. Eldridge, J. L., and G. L. Krapu. 1988. The influence of diet quality on clutch size and laying pattern in mallards. Auk 105:102-110. Gollop, J. B., and W. H. Marshall. 1954. A guide for aging duck broods in the field. Mississippi Flyway Tech. Sect. 14 pp. Heitmeyer, M. E. 1988. Body composition of female mallards in winter in relation to annual cycle events. Condor 90:669-680. Krapu, G. L., A. T. Klett, and D. G. Jorde. 1983. The effect of variable spring water conditions on mallard reproduction. Auk 100:689-698. Lantis, D. W. 1942. Sage of the San Luis Valley in Colorado. Folks and Fortunes 1:38-40. Pattenden, R. K., and D. A. Boag. 1989. Effects of body mass on courtship, pairing, and reproduction in captive mallards. Can. J. Zool. 67:495-501. Sowls, L. K. 1955. Prairie ducks. Stackpole Co., Harrisburg, PA. 193pp. Szymczak, M. R. 1986. Characteristics of duck populations in the intermountain parks of Colorado. Colorado Div. Wildl., Tech. Publ. 35. 88pp. �87 APPENDIX E NESTING OF INSTRUMENTED ADULT FEMALE MALLARDS IN THE SAN LUIS VALLEY, COLORADO Cross-seasonal interactions between winter body condition and reproductive success of waterfowl have been suggested (Heitmeyer and Fredrickson 1981, Heitmeyer 1985, Pattenden and Boag 1989), but no data are available on the winter body condition of individual females and subsequent reproductive success. Our objective in this study was to measure reproductive success of adult female mallards (Anas p1atyrhynchos) whose January body condition was known. STUDY AREA This study was conducted in the San Luis Valley (SLV) , in south-central Colorado. The SLV is a 12,960 km2 intermountain basin, bounded by the San Juan Mountains to the west and the Sangre de Cristo Mountains to the east. As a result of the surrounding mountains and a valley elevation of 2,286 to 2,438 m, the SLV has an arid climate characterized by short, cool summers and cold dry winters (Lantis 1942). From 1964 through 1980, breeding pair estimates averaged 25,371 pairs, but have declined since then, primarily because of decreasing habitat (Szymczak 1986). Mallards are the most abundant nester (Szymczak 1986). An average of 18,734 ducks wintered in the SLV (1984-90 average, Colo. Div. Wi1d1., unpub1. data); most are mallards wintering on the Monte Vista National Wildlife Refuge (MVNWR). Wintering mallards rest on open water maintained by pumping or artesian flow, and forage in nearby grain fields. METHODS We captured mallards wintering on MVNWR with Salt Plains bait traps (Szymczak and Corey 1976) or cannon-projected nets (Dill and Thornberry 1950) from 11-18 January and 20-22 February 1987 and 11 January through 4 March 1988. Data on age, sex, weight, and wing length were obtained, and a condition index (Ringe1man and Szymczak 1985) calculated for each. We summarized the condition indices of adult females captured the first trapping day of each trapping period, then assigned adult females to 1 of 3 condition classes based upon their condition index relative to the population distribution of the females captured. Subsequently, birds with a condition index in the upper 33% of the range were classified as in "good" condition, the middle 33% were considered "average," and the lower 33% were considered in "poor" condition. In January 1987, 52 adult females in good condition and 51 in poor condition were instrumented with 26 g back-mounted transmitter packages attached with a harness similar to that described by Dwyer (1972). In February 1987, 18 adult females in good condition and 17 in poor condition �88 were instrumented. In January 1988, 52 adult females in good condition and 51 in poor condition were instrumented. High mortality of instrumented females in 1987 prompted us to anticipate high mortality again in 1988. Initially, we planned to trap weekly and reuse radios collected from dead females, by applying radios to adult females based upon their condition index relative to the condition index classes used during the 11-18 January trapping period. This protocol resulted in transmitters being reapplied to 23 adult females, 6 in good condition, 1 in average condition, and 16 in poor condition. However, by early February extremely high mortality, difficulties with trapping, and changes in the condition indices of the population made it impractical to reuse radios weekly. Consequently, all radios subsequently collected were reapplied during trapping on 29 February through 4 March. Procedures for determining the relative condition of each bird compared to the population were similar to that used in early January. We instrumented 22 females in good condition, 17 in average, and 24 in poor condition in late-February and early-March. Standard techniques were used to obtain weekly locations of instrumented ducks from the ground (Cochran 1980:517-518) using vehicle-mounted and handheld antenna-receiver systems. Birds not found early in the week were located from the air (Gilmer et al. 1981) using a strut-mounted antenna attached to a Cessna 182. All birds located from the air were ground-checked the next day to determine if they were alive or dead. Any birds contacted from the ground that were in unusual locations, did not have attenuating signals, or were in the same location for 2 consecutive weeks were checked visually to determine whether they were alive or dead. In both years, instrumented females were monitored through June to locate their nests. When a nest was found, it was checked after the estimated hatching date to determine success. RESULTS In both years, 71 females were possibly alive during the nesting period. Each year, only 2 instrumented females were found with nests. In 1987, a female instrumented in poor condition in January and another female in good condition in February nested. In 1988, both nesting females were in poor condition when instrumented in January. None of these four females successfully hatched any ducklings. DISCUSSION The low number of instrumented females nesting each year may reflect effects of the transmitter package on weight dynamics of these instrumented females, or females wintering in the SLV may have low reproductive rates. Instrumented females may not be able to recover body mass lost during the instrumentation adjustment period, and never obtain the body reserves important for mallard reproduction (Krapu 1981). Alternatively, the generally low body condition of mallards wintering in the SLV may result in low reproductive rates. Our results suggest that body mass losses identified for instrumented birds (Chapter 4) affected survival of our samples. We caution other researchers to carefully evaluate any effects their marking technique may have on the behavior being studied. �89 LITERATURE CITED Cochran, W. W. 1980. Wildlife telemetry. pp. 507-520 in S. P. Schemnitz (ed.). Wildlife management techniques. Fourth ed. Wildlife Soc. Inc., Washington, D. C. Dill, H. H., and W. H. Thornberry. 1950. A cannon projected net trap for capturing waterfowl. J. Wildl. Manage. 14:132-137. Dwyer, T. J. 1972. An adjustable radio package for ducks. Bird-Banding 43:282-284. Gilmer, D. S., L. M. Cowardin, R. L. Duval, C. W. Schaiffer, and V. B. Kuech1e. 1981. Procedures for the use of aircraft in wildlife biotelemetry studies. u.s. Fish and Wildl. Serv., Resour. Pub1. 140. 19pp. Heitmeyer, M. E. 1985. Wintering strategies of female mallards related to dynamics of lowland hardwood wetlands in the Upper Mississippi Delta. Ph. D. Thesis, Univ. Missouri, Columbia. 376pp. _____ , and L. H. Fredrickson. 1981. Do wetland conditions in the Mississippi delta hardwoods influence mallard recruitment? Trans. North Am. Wildl. Nat. Resour. Conf. 46:44-51. Krapu, G. L. 1981. The role of nutrient reserves in mallard reproduction. Auk 91:28-38. Lantis, D. W. 1942. Sage of the San Luis Valley in Colorado. Folks and Fortunes 1:38-40. Pattenden, R. K., and D. A. Boag. 1989. Effects of body mass on courtship, pairing, and reproduction in captive mallards. Can. J. Zool. 67:495-501. Ringelman, J. K., and M. R. Szymczak. 1985. A physiological condition index for wintering mallards. J. Wild1. Manage. 49:564-568. Szymczak, M. R. 1986. Characteristics of duck populations in the intermountain parks of Colorado. Colorado Div. Wildl., Tech. Publ. 35. 88pp. _____ , and J. F. Corey. 1976. Construction and use of the Salt Plains duck trap in Colorado. Colorado Div. Wildl., Div. Rep. 6. l3pp. Prepared by: Michael R. Szymczak Wildlife Researcher C ��91 Colorado Division Wildlife Research October 1991 of Wildlife Report JOB PROGRESS REPORT State of Colorado Project W-152-R-4 Work Plan Job Title: 1__ : Job Evaluation Period Covered: Authors: Avian Research - Migratory Game Birds 19 of nesting habitat 1 April 1990 through David W. Gilbert. management 31 March James K. Ringelman for ducks 1991 and David R. Anderson Personnel: D. Anderson, Colorado Cooperative Fish and Wildlife Research Unit; J. Ringe1man, M. Szymczak, Colorado Division of Wildlife; D. Gilbert, Colorado State University; S. Brock, S. Berlinger, A. Morkill, R. Schnaderbeck, U.S. Fish and Wildlife Service. ABSTRACT Personnel at the Monte Vista National Wildlife Refuge (MVNWR) used transect surveys to collect information on duck nests annually since 1964 (except 1977). Total transect distance was originally (1964-1968) 323.6 mi per year (one walk), but was latter reduced by half. The 141 transects (71 later years) were run twice annually (plus additional nest fate checks). Transect surveys sampled 4-5.5% of the 14,189 acre refuge. Mallards composed 54.5% of the duck nests on MVNWR, followed in abundance by teal species and pintail. Units 6, 9, and 18 had highest nest densities (1164, 1050, and 1366 nests/mil respectively) and units 5, 20, and 23 had the lowest nest densities (27, 156 and 140 nests/mil respectively). Refuge-wide nest densities ranged from a low of 92.7 nests/mi2 in 1979 to a high of 417.9 nests/mi2 in 1973. Mean annual nest success was 49.4%, (52.4% for the 4,156 nests included over the entire period) but ranged from 27% in 1978 to 72% in 1966. Available habitat was quantified using color-infrared aerial photography, ground truthing and geographic information system software. Ground cover on the MVNWR was 48.4% baltic rush, 29% greasewood and rabbitbrush, 4.8% saltgrass, 3.4% cattail and 4.6% grass species. The remainder of the refuge has varying small amounts of 6 other vegetation types. Ten percent of the refuge was non-surveyed, water was 4.25% and roads were <1%. The 2 most predominant cover types, baltic rush and greasewood, accounted for 68% and 16% of total nests, respectively. Species composition and nesting success of 4,156 duck nests located over 26 years provide a basis to evaluate the benefits of habitat management practices including grazing, water application, burning and predator control. Three different grazing schedules were utilized. One, the rest rotation schedule, will allow grazing effects to be evaluated. Grazing ranged from 0.0 to 1.8 AUM/acre. Prescribed burning treatments were conducted 14 times. Eight such burns were evaluated and �92 ABSTRACT (cont.) indicate a decrease in nest density the year of the burn. Predator control was conducted at 3 intensities. The first period saw widespread use of poison and was significantly effective in decreasing nest failure due to predation as compared to a second, limited predator control effort period. A third period again had intensive predator control, but no poison and did not significantly reduce predation on .duck nests. Evaluation of a haying program (1964-1976) indicated that there was a slight impact on nesting density during cutting. Some confounding was found between treatments and is reported. The interim completion report for this project is presented this segment. Additional analyses will be performed next segment, and a comprehensive monograph will be prepared for submission to a scientific journal. �93 EVALUATION OF NESTING HABITAT MANAGEMENT FOR DUCKS David W. Gilbert James K. Ringelman David R. Anderson P. N. OBJECTIVES 1. Relate nesting duck species composition, density to habitat management practices. nest success rate, and nest 2. Assess changes in wetland and upland vegetation between 1962 and 1985 by contrasting digitized habitat information derived from aerial photographs. 3. Determine nesting habitat preferences of duck species by comparing of nesting habitat with relative habitat availability. usage SEGMENT OBJECTIVES 1. Locate records on grazing, burning, water application and predator control (habitat treatments) for individual wetland units on the Monte Vista National Wildlife Refuge (MVNWR). Computerize these data for entry as independent variables for categorical data analyses. 2. Conduct categorical analyses of nest transect data, employing log-linear models, logistic regression and contingency table methods to test hypotheses concerning the effects of habitat treatments on the species composition, nest success and nest density of breeding waterfowl. 3. Obtain aerial photography of the MVNWR for three time periods (1960's, 1970's, and 1980's). Using ARC/INFO and other remote sensing software, digitize vegetation habitat maps for the MVNWR. Calculate areal coverage of habitat types, and relate changes over time to habitat management practices and natural vegetation succession. 4. Relate changes in waterfowl nesting densities, distribution success to changes in vegetative associations over time. 5. Write interim and final reports, and submit findings to relevant scientific publications and interested natural resource agencies. and nesting STUDY AREA Duck nesting and management records evaluated were collected on the MVNWR in the San Luis Valley (SLV), 9.6 km (6 mi) south of Monte Vista, Colorado. The MVNWR is at 2,316 m (7,600 ft) elevation and is considered a cool desert, high elevation mountain park. Surrounding mountain ranges, including the San Juan range on the west and the Sangre de Christo mountains on the east, collect snow pack and subsequently supply water to the SLV via the Rio Grande River and a network of irrigation canals. Underground sources of water from �94 vast aquifers also are an important source of water for both the SLV and the MVNWR. The refuge began to use these water sources to produce and enhance wetlands in 1953, when it was established. A network of artesian wells, pumped wells, ditches and dikes have since been developed to keep many of MVNWR 24 management units (5,742 ha, 14,189 acres) flooded to varying depths for waterfowl and other wildlife to use. The SLV receives less than 30 cm (12 in) of precipitation annually. Therefore, the refuge and surrounding agricultural communities rely on irrigation and pumped water from underground sources to supplement the low precipitation. Vegetation on the MVNWR is predominantly baltic rush (Juncus balticus), greasewood (Sarcobatus vermiculatis), and rabbitbrush (Chrysothamnus spp.). General topography can be described as extremely flat with an overall minor downward slope from west to east. Szymczak (1986) further describes characteristics of the MVNWR. The physical boundaries of the refuge stretch 12.9 km (8 mi) east from the base of the San Juan mountains, and is 6.4 km (4 mi) wide from north to south. The 24 individual management units are separated by fences, roads, and/or ditches (Fig. 1). Details on size and other characteristics for each unit are given in Appendix A. Most units have the ability to be managed separately from other units with respect to grazing, burning and water application. The MVNWR has recorded 194 different species of migratory and nonmigratory birds; about one-third (66 species) are listed as common or abundant during some time of the year (USDI, USFWS 1986). Principal duck species nesting include mallards (Anas platyrhynchos), gadwall (Anas strepera), pintail (Anas acuta) blue-winged teal, (Anas discors), cinnamon teal (Anas cyanoptera), shoveler (Spatula clypeata), and redhead (Aythya americana). Other duck species nest at MVNWR, but are less numerous and were not examined in this study. Banding studies (Szymczak 1986) reveal that the mallard population is largely resident year round. The other species are mostly migratory, and few winter in the SLV. METHODS The following sections describe the many sources of data collected and how they are used in analysis. Nest data originate from actual or summarized survey forms provided by the refuge. These data were entered into a general computerized spreadsheet for analyses using SAS (SAS Institute 1987) and Quattro Pro (Borland International 1990). Area, size, length of transects and other similar measurement information used to derive density estimates and cover area were computed from GIS (Arc-Info) analysis of aerial photographs. Refuge features were corrected for scale using U.S. Geological Survey 1:24000 topographic maps. Nesting Data Nesting survey data used in this analysis extended from 1964-1990 excluding 1977, a drought year when no survey was conducted. The duck nests detected and used in all evaluations were as follows: �GJ 3: - .•.. "•.... "0 •.... C ftJ •.... ftJ o .•.. ~ ftJ z: ~ en ..-> CIJ o C ~ X - i ; 95 �96 Species No. Detected Mallard Percent 2,264 54.5 Teal Pintail Gadwall Shoveler 563 359 251 116 13.5 8.6 6.0 2.8 Redhead Unknown 83 529 2.0 12.6 4,156 ·100.0 Total Other minor species were removed from analysis. Teal species include bluewinged teal, cinnamon teal and green-winged teal (Anas crecca), but nearly all (550 of 563) were blue-winged or cinnamon teal. Nest data were used for all nests located during mid-May and mid-June searches. June walks were used to determine the fate of May nests as well as to locate new nests. A July walk was included only for the purpose of determining the fate of nests located in June. In some years, nests located in July were included because nesting in those years was thought to be delayed. These nests, however, were removed from analysis to maintain consistency. Analysis of May to June nest ratios in years with July nests do not reveal exceptionally later than normal nesting chronology when the entire period is examined. Production and density estimates from years where late nests were recorded are not comparable to other years. Appendix B gives the year and number of late nests eliminated from analysis and chronology of nesting between years, thus the rational for their removal. Information collected at each nest included: date, unit number, transect number, species, incubation stage, number of eggs, and vegetation cover surrounding the nest. If nest failure was encountered, probable cause was recorded. Distance to the transect centerline was often collected as an aid in nest relocation, but in some years distance data were discarded nest records were summarized. The 529 nests recorded as "unknown" were reapportioned among the other species based upon species composition values for each year. Unknown nests typically were labeled as such if the hen was absent from the nest or the eggs destroyed. The percentage of unknown nests in the early years was greater than in later years (Appendix C), probably because a reference egg collection used in later years facilitated identification. Information on refuge management programs was taken from Annual Narrative Reports (MVNWR 1964-1990), and was supplemented by detailed files on specific activities such as grazing and water application. Data in this report can be considered final for the period of record described. Values were derived from actual nest data forms collected, not from summarized reports. Transect Survey The transect survey design resulted designed such that 640 acres of transect from pre-sampling in 1961-63. sampling would result in nest It was �97 estimates within 10-15% of the true value 95% of the time. In early years (1964-68), 142, 16.5-ft. wide "strip" transects, 300 feet apart (west to east) were used. At w - 8.25 ft., (8.25 ft./side of transect centerline), 5.5% of the refuge was sampled. The transects covered approximately 320 mi. each walk (described below), sampling 640 acres of the 11,570 acres available for nesting. The survey technique called for searchers to "line sight" 2 or more numbered, transect marker poles with the aid of binoculars. The searcher then walked the transect centerline and observed for nest signs or ducks flushing from a nest. Upon location of a nest, surveyors marked nests and recorded distance measurements from transect centerline so the nest could be relocated during the subsequent nest fate search. Nesting information was also recorded at this time. Beginning in 1969, the number of transects were halved by removing all even-numbered transects. In order not to decrease the area sampled by half, transect width was increased to 24 ft. (w - 12 ft.), resulting in coverage of 4.0% of the total nesting habitat. Sampling in 1971 was further reduced (that year only) to walking every other odd-numbered transect (1 of every 4 original transects) because of a labor shortage and a very dry year when nesting was thought to be poor. Since 1972, all odd-numbered transects have been walked twice each year. Transect widths were kept at 24 ft from 1971 through 1979, changed back to 16.5 ft during 1980-1986, again increased to 24 ft for 198687, then changed back to 16.5 ft wide 1988-1990 (Table 1). All data are corrected to adjust for these variations, although these changes cause the precision of the nest density estimates to vary. Nest abundance was estimated from the number of nests found in the strip divided by the fraction of the area sampled. Production estimates were derived from the number of total nests corrected for the percent of each species in the breeding population, species composition of the nests found, percent hatch success, and brood size for each species (see Appendix D for weighting calculations). Our interest was with nest densities and variability in nest density through time in relation to a variety of natural conditions and management treatments. Brood data and production estimates were not considered here. All values are reported as nests/mi2 and are corrected for nests undetected in the strip. Estimation of Nest Density An assumption of a strip transect require that all nests are found within the strip. This assumption was shown to be unrealistic by Anderson and Pospahala (1970), who estimated that approximately 11% of the nests at MVNWR were not detected, even with the narrow transect width of 16.5 ft. Thus nest density was estimated using contemporary theory for line transect sampling (Burnham et al. 1980 and Buckland et al. 1992) and the distance from detected nest to the transect centerline. The percent of nests undetected varies with �98 Table 1. Summary of changes in transect survey statistics due to changes in search effort, 1964-1990.~ Years shown in bold italic indicate that measurements from each nest to the centerline of the transects are available. Width Year Total Acreage Year Width Total Acreage transect sampled ft. transect sampled ft. (2w) length, (2w) length, one walk one walk 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 16.5 16.5 16.5 16.5 16.5 24 24 24 24 24 24 24 24 323.6 323.6 323.6 323.6 323.6 170.6C l70.6c 80.7 161.6 161.6 161.6 161.6 161.6 647 647 647 647 647 496 496 253 469 469 469 469 469 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 24 24 16.5 16.5 16.5 16.5 16.5 16.5 24 24 16.5 16.5 16.5 161.6 161.6 161. 6 168.8 168.8 168.8 168.8 168.8 168.8 168.8 168.8 168.8 168.8 469 469 323 337d. 337 337 337 337 337 491 337 337 337 aValues may differ slightly «1%) from that reported by MVNWR but were determined using GIS and are assumed to be more accurate. bNo survey was conducted in 1977. CUnit 6 had extra effort during 1969 & 1970. dUnit 24 added to survey in 1981-90. changing strip width over the years (see results). Therefore, unbiased estimates of nest density (D) were computed with program DISTANCE (Laake 1991) using the following general estimator: 15 - nr(o) /2L where n - the number of nests det~cted within the strip, the estimated probability density function of the distances, L the length of transect line. £(0) The central issue in estimation of density from line transects is the selection of a proper model for £ (x) , the probability density function for the distance data, x. Here a half-normal key function was used with a Hermite polynomial adjustment function, however estimates of nest density were similar for other models of £(x). The estimator of D can be used for individual �99 species, management units, and years, or can be pooled over some of these categories. Standard procedures were used to estimate standard error, confidence intervals and other measures of precision. Data were also evaluated for differences in detectability among species and between years using Chi-square tests (whenever nest distance data from transect centerline were available). Years were pooled to increase sample size when evaluating differences in detectability between species. Final estimates for each year were derived using data from all duck species and all years with distance measurements at both w - 8.25 ft and w 12 ft. This approach fully utilized available distance data (n - 1,476 nests with distances for w - 12 ft, and n - 1,788 for w - 8.25 ft distance years). Values used to correct any w - 12 ft year (refer to Table 1) were obtained from these data. However, data were truncated at 11 ft-1l in. to remove heaping near the transect boundary. Values to correct derisity for any year in which w - 8.25 ft were calculated the same way. Here again, the last 0.25 ft were truncated to eliminate heaping near the transect boundary. Density estimates for individual species were calculated using the same methods, but because of smaller sample size had less precision. All estimated nest densities reported here are corrected for undetected nests using methods outlined above. Vegetation Mapping, Transect Length and Area Calculations The Arc-Info Geographical Information System (GIS) was used to derive the cover attributes of area, patch perimeter, total transect distance, and transect distance within cover patches. These measurements are important to determine use/availability values. The original polygon delineation of refuge features used in GIS were derived from color infra-red photography of MVNWR, at a scale of 1:7,920 (8 in on photo equaled 1 mi). Polygon size was limited to approximately 1 acre as the minimum mapping unit (Campbell 1987). Some smaller polygons occurred where a road or other feature bisects a given polygon. Polygons of vegetation associations were delineated on mylar overlays wherever distinct contrast differences could be detected between patches from the photograph. A baltic rush patch, for example, could easily be delineated form a greasewood upland community directly from the aerial photographs. However, some patches that had even interspersion of several plant species initially had only the external perimeter delineated, then a ranking of species dominance was later assigned during field inspection ("ground truthing"). Although ground truthing was done 5 years after initial photography, it is unlikely that any patch changed significantly with respect to composition. It is more likely that patch boundaries advanced or receded for a given patch but composition remained constant. Most fields had to be walked thoroughly to determine actual plant composition of plants for a dominance ranking. Some species appeared dominant when in bloom and viewed from a distance, but actually make up a small fraction of the vegetation complex. Most patches were single species, but if not, patches were ranked for the 3 most predominant species in descending order. Patches with >4 dominant plant species were labeled as "transition". A typical example would be a seasonally-flooded greasewood-rabbitbrush community in transition to a spikerush-baltic rush, sedge-wet meadow (scientific names given in a later table). Only a relatively small fraction «25% of vegetation polygons) of the refuge could not be classified into patches containing 1 dominant plant �100 species. Transect locations were noted on the mylar overlays whenever a transect marker pole could physically be located on the photograph by association to a recognizable feature. Upon completion of ground truthing, unit boundaries, polygons, and known transect locations were digitized into Arc-Info GIS. Remaining transect lines were generated easily by Arc-Info because of the known spacing. Attribute information were then entered into the GIS, yielding summary information. Digitizing and polygon summary concerning area, perimeter, and individual transect length was performed by TGS Inc., Computer Mapping Division, Fort Collins, Colorado. Use of photographs was restricted to the approximate effective areas. Mylar overlays were computer-registered to U.S. Geological Survey, 1:24,000 topographic maps to correct for any photographic distortion error. The polygon "stretching" required for correction was minor, but enhanced the accuracy of polygon boundaries. Original study plans called for comparison of the 1985 analysis with earlier years aerial photographs. Two sets of photographs were found (1969 and 1978 black and white photographs) and were enlarged for the comparison. It was hoped to that changes in polygon boundaries could be detected, thus tracking succession and wetland development. Unfortunately, delineation problems associated with the black and white photography prohibited this analysis. Only major wetland development changes were obvious and some general trends were observed and are reported. This technique offers promise if additional infrared photography is obtained at a future date. Additional Data Evaluated Data were also available on water conditions in the SLV for determination of relative nesting conditions off of the refuge. Data for this purpose came from gauging station records collected above Del Norte, Colorado. This station serves as a monitor of water within the Rio Grande drainage prior to extensive diversion for irrigation. Finally, also included are estimates of breeding populations from surveys performed in the SLV by the Colorado Division of Wildlife for the same period as the nesting survey. This survey was an aerial transect survey which enumerated breeding pairs and included most of the SLV. Breeding pair populations within the SLV are probably related to the nesting density on the refuge. RESULTS Species Composition Adjustments A total of 4,156 duck nests was found during 1964-1988 (Table 2). Annual differences in number of nests found are attributable both to real changes in nest density and variable search effort. Mallards were the most common nesters, followed in abundance by teal species, pintail, and gadwall (Table 3). Species abundance changed over time (Fig. 2). �100 , ,< i it <. K:SI5 iJ 5 i , < i ts:SJ '''" "'" '"" "'11 1968 1970 1972 1974 I< <I LL:1Ii [ <• p::::;;i4 m r7 ] i," <l , < i 1< \j [ '" i K <I i '" q iC '" 10 ; , m P' 7 j c:s::::s r 7] V 71 I eo ••••• coo Q) ~ Q)4O D.. 20 0' "II "'" 1964 1966 1111' 1976 11"' 11"' 1979 1981 11'11 1983 11"' 11"' 1985 1987 1111, " 1989 Year D Mallard • Teal III Pintail II] Gadwall ~ Shoveler ~ Redhead Fig. 2. Species Composition of duck nests on MVNWR, 1964-1990. t-' o t-' �102 Table 2. Number of duck nests found on transects during 1964-1990.8 Year Number Year Number 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 261 212 260 244 315 230 229 114 127 239 109 65 95 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 Total 55 53 89 104 110 114 150 152 197 262 150 130 90 4,156 Data represent real changes in nest density caused by differential search effort (see Table 1). Nest data were not collected in 1977. 8 Estimation of Nest Density Nest detectability did not differ among species or years (P > 0.05). A histogram of distance data available for all duck species in all years when w - 12 ft illustrates the decreasing probability of nest detection with increasing distance from transect centerline (Fig. 3). Heaping of nests at 0 and 3 ft and apparent "missing" nests at 1 ft are shown. Heaping at 3 ft probably results from rounding to "1 yard" rather than measuring nest distances. A similar situation also occurs at 10 ft. The low number of nests at 1 ft is caused by observers categorizing nests close to centerline as being on "center1ine". The 12th ft interval actually was only 1 in. wide (at 144 in.) because nests were only included out to 12 ft. This also is the case for the last 0.25 ft in the w - 8.25 ft years. Histograms for most species and years show little deviation from this pooled histogram, as reflected in the Chi-square tests. Histograms for pintail and teal, however, did differ slightly from than that shown for all ducks. Teal nests were generally less detectable than other species and the pintail data were problematic because fewer than expected were found near centerline due to their substantial preference for greasewood. Greasewood is sturdy, full of thorns, and may be avoided by nest searchers, thus causing nests near the centerline to be missed. Detectability difference of nests in the 2 major vegetation groups, greasewood and baltic rush, were insignificant (X2 - 7.12, P - 0.789), but the greasewood histogram resembled that of the pintails. Estimates of annual nest density varied markedly during 1964-90 (Fig. 4, Appendix E). The sampling variance of n, (var(n)), was about 1.7 n, and the coefficient of variation (cv) of n ranged from 7.3 to 17.9%. The cv(f(O)) �200 ~--------------------------------------------------~ 150 •.. Q) .0 E 100 ::l Z 50 o centerline 1 2 3 7 8 4 5 6 Distance from transect centerline 10 9 {Ft 11 12 1 Fig. 3. Nest detection at distances from transect centerline, data from all species during all years with distance data available. (n =1,476 nests) f--' o w �500 ~-----------------------------------------------. --~cen 400 Q) -0 t5 Q) 300 c "'C Q) 10 -_E t5 w 200 100 o 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 Year Fig. 4. Estimated nest density, nests/sq. mi. MVNWR 1964-1990, 19n excluded • ..:t a rl �105 varied from 6.1 to 10.1% during 1964-1990. Analysis of the relative contribution of var(n) vs. var(£(O)) indicated the 2 sources to be of similar magnitude. Mean estimated density for all survey years and cv values for the w - 12 ft years for individual species are: CV Species Mean estimated density Mallard 164.5 8.2 Teal 49.5 10.1 Pintail 35.6 8.5 Gadwall 19.8 11.6 Shoveler 10.4 17.2 The above values indicate greater uncertainty in the estimates of nest density for the minor species due to smaller sample sizes. Some units of the refuge consistently have more nests than do other units (Fig. 5). Annual importance to nesting of each unit fluctuates and is not shown, but clearly there are large differences between the best and worst units. The 4 best units (3, 8, 9 and 18) compose 22.9% of available nesting habitat and account for 49.3% of nests detected. Conversely, the worst 4 units (5, 20, 22 and 23) account for 12.4% of available nesting area but only 3.2% of the nests found. Unit 24 is a better nesting unit than figure 5 would indicate; it was added to the survey in 1981 and only nests found from 1981 to 1990 are reflected in the figure. Appendix F gives yearly and mean nest density for all units. Breeding Pair Survey A positive relationship with low correlation (r - 0.0896) existed between mallard nesting density on MVNWR and the mallard breeding population surveyed in the SLV (Fig. 6). Variability in the data are probably caused by relative differences in water conditions between the MVNWR and the SLV. Most mallards are resident year round in the SLV, (Szymczak 1986) and are therefore partially dependent on wintering conditions in just 1 region. This same relationship would not be expected for the more migratory species because many migrate out of the SLV after the survey and do not winter in the SLV. Nevertheless, refuge nest density, heavily influenced by mallards, is only a weak indicator of the annual breeding population in the SLV. Total numbers of breeding pairs have declined in the SLV but remained relatively stable at the MVNWR (Fig. 7); particularly for mallards (Fig. 8). Thus, the refuge is important in maintaining local duck populations. There is no apparent shift to MVNWR as habitat was reduced elsewhere in the SLV, merely a reduction in numbers valley-wide. Szymczak (1986) believed that reduced habitat in the SLV was caused by the reduction of flood irrigation, which create wetlands from runoff. The relationship between North American breeding pair surveys (U.S. Fish and Wildlife Service 1989) and the SLV breeding pair survey show low correlation for either mallards, total ducks, or total species other than mallards (r - 0.149, 0.187, and 0.099 respectively). Thus, the �t-' o 0\ 25 ~------------------------------------------------------------~ ~ I '::::: It@rl " of available area contributed by unit Q) rn 15 t-------------I - CO ....., "of all nests found {:::::::';:':In each unit Note:Units12 & 13 arenotsurveyed. C Q) ::;::: .;:::~~: U 'Q) n, 10 I m',f--. --------1 ~:}i ..::: :;~~~f 5 t---- ::.:-. o 1 2 3 :~~~~t .:}: ..;:.: :::~;: 4 5 :'i:: 1 6 7 8 9 10 11 14 15 16 17 18 19 20 21 22 23 24 UnH Fig. 5. Percent available area and nests for each unit, MVNWR 1964-1990, 1977 excluded. See Appendix A for % nests I % area values. �300 ~----------------------------------------------~ 13 .. o o o o 50 0 o o ~----~----~~----~----~------~----~------~ o 2,000 4,000 6,000 8,000 10,000 12,000 Estimated mallard breeding pairs, SLV 14,000 Fig. 6. Relationship between mallard nests MVNWR & mallard breeding pairs SLV, 1964-1990. No survey done In 19n & 1985. f-' a -...J �I-' o co 35,000 CJ) l.- [ 30,000 II CJ) c .- II SLVtotal pair. MVNWR excluded MVNWR total pairs - - 25,000 r- 20,000 ~ - 15,000 i- - - - - - - - - - U Q) Q) l- .e 0 - - - _- - - - - - - - - - - - - - - - - - - - _- - - - - - -- - - - - .- I- Q) .e E 10,000 ~ - - ,-- 5,000 >--III--~lf~ -~~~-~tt~J~11 -- 68 68 70 72 74 76 78 80 82 Year Fig. 7. SLV total breeding pairs and total breeding pairs on the MVNWR. No survey was conducted In 19n & 1985. - - - ~ ~ - - ..- ; .' 0 64 - ._I ::J Z -- 84 8S I'll ~ 88 J -90 �14,000 .----------------------------. 12,000 1----- ~ ·cuCo 10,000 t- 8,000 I- 6,000 I- 4,000 I- 2,000 I- O) ----.-.--.--.-- .. • II SLY mallard pairs MVNWR excluded MVNWR total pairs .5 "0 m... .0 '0 ... ~ -.- E ::l Z ~I~. o 64 66 sa 70 72 74 76 78 eo e2 84 e6 ee 90 Year Fig. 8. SLV mallard breeding pairs and mallard breeding pairs on the MVNWR. No surveys were conducted in 1977 & 1988. I--' o \.0 �110 SLV breeding populations evidently fluctuates relatively independent of the North American population surveyed. Water Early water, defined as water applied to wetland units before 1 April, is needed to attract nesting ducks to the MVNWR (Schroeder et al. 1976). The MVNWR staff secured increasing amounts of water for early water applications (Fig. 9). Valley conditions (as indexed by Rio Grande River water), however, are more susceptible to the natural variations in precipitation (Fig. 10). Figure 11 shows the water by source for the totals given in figure 9. Vegetation Composition at MVNWR The MVNWR, which totals 13,912 acres (not included are unit 12, or units 13 and 19 west of the Monte Vista Canal), was classified into 697 polygons for GIS analysis. Nine polygons (1,506 acres) were not surveyed (generally agricultural fields). Five additional polygons (88 acres) were county roads between units and the Empire Canal. These 14 polygons were removed from consideration. Of the remaining 683 polygons important to nesting ducks, 513 (75%) were single-feature or single-vegetation patches. The remainder were patches consisting of 2 or more species in a patch. All areas (except the 591 acres of open water and the non-surveyed areas) were considered as habitat available for nesting, because ducks are known to nest on dikes, ditch banks, and near buildings. Accordingly, total area available to nesting ducks was 11,727 acres (18.3 mi2, excluding unit 12, units 13 and 19 west of Monte Vista Canal, all non-surveyed areas and open water bodies). There were 11 types of vegetation and transition type associations (4 or more dominant species in 1 patch Table 4). Even though there were 71 combinations of these types, the majority of polygons could be delineated into single-species patches unless they were extremely heterogenous. A total of 772 acres (146 polygons, 6% of the surveyed refuge) did not contain vegetation and were classified as: No. polygons No. acres Attribute 81 Open Water 591 28 134 Dike roads 7 9 Parking area& 30 38 Ditches 146 772 &Includes research facility. Individual unit characteristics varied (Appendix G). Addition printouts describing individual polygons will be filed at MVNWR and are not reported here. All digital data and computer-generated maps derived from the GIS work �600,000 ,.----------------, 35,000 ,.---------------, - 30,000 •.. ca:: 500,000 r---t 25,000 ;S Q) _ 1U 3: - 20,000 ! 15,000 e--I-I •.. 0 -c 1::: 11111111 _ lu III;IIJIIIIIIIIIIII ~ 300 000 , 1----------. 200,000 ~ ••••••••• - •• - I111I1I111111I 0'···················--------1 90 75 80 85 70 65 Year fig. 9. MVNWR water total, all sources for 1964·1990. ' '0 1D .e - 400 000-- 100,000 01---------------------------. 65 70 75 80 85 90 Year Fig. 10. Rio Grande total water measured at the Del Norte gauging station, 1964·1990. (An Index of water conditions In the SLV) I--' I--' I--' �•..... •..... N 35,000 ,---------------------------. Monte Vista Canal 30,000 II Spring Creek HtM Artesian Water Pumped Water Empire Canal Other Decreed Water 25,000 t-----------------------l ~ Q) 'ta ~ 20,000 (5 Q) .e e 15,000 ~ 10,000 5,000 o 64 66 68 70 72 74 Year 76 78 82 84 86 "rot. 1981, pump & artesian omitted separately brol Fig. 11. Water by source MVNWR 1964-1990 80 1982, pump & artesian omitted separately 88 90 �113 are also on file with the Migratory Division of Wildlife. Nesting Game Bird Program Unit of the Colorado Cover Preference The MVNWR is dominated by 2 plant species: baltic rush and greasewood (some rabbitbrush also in association with the greasewood). During ground truthing, greasewood communities were classified as either having an understory or devoid of understory (e.g. greasewood on otherwise alkali field). Ducks nested more commonly in greasewood bushes with some understory (typically rabbitbrush, baltic rush, saltgrass or weeds). Nest records do not provide comparable detail, but this information was quantified during ground truthing and may be useful to refuge managers in deciding where to develop wetlands. Preference for nest vegetation is evident from nest records (Table 5). Of the 4,156 nests evaluated, 2,582 (62%) were found in baltic rush (48.4% of the refuge). An additional 226 nests were found in baltic rush combined with another species, but with baltic rush the dominant type. Thus, 68% of all nests were associated with baltic rush. Conversely, greasewood covers 29% of the refuge yet accounted for only 16% of nests (619 nest sites). Less than half (295 of 619) of all nests were found in pure stands of greasewood; the remainder were in mixtures of greasewood and some other vegetation. Of the 226 baltic rush/combination nests, 66 were in cattail, 65 were in spikerush, 47 were in sedge, and 15 in greasewood; the few remaining nests were distributed among the other types (Table 5). The greasewood/combinations consisted of mixtures of baltic rush (140 nests), saltgrass (121 nests), and other grass species (31 nests). Many nests located in other nesting cover types also had baltic rush as a vegetative component. Saltgrass, cattail and weeds also serve as important plant species when nests are located in combination with other vegetation. Duck species preference varied slightly among cover types (Table 6). Pintail preferred greasewood and saltgrass, whereas shoveler appear to avoid greasewood. Redhead nest in cattail more than other species, whereas gadwall avoid this covertype. However, gadwall appear to be the most general nester, nesting at a higher rate in the "all other" category more often than the other duck species. �114 Table 3. Species composition of duck nests found (i.) for the period 19641990, adjusted for unknown nests. Year Mallard Teal spp. Pintail 1964 71 8 11 1965 73 8 1966 73 1967 Gadwall Shoveler Redhead 6 2 3 8 5 2 5 8 10 5 3 1 70 8 12 4 3 2 1968 72 8 13 4 2 1 1969 66 10 12 6 4 2 1970 62 14 16 2 5 1 1971 67 11 11 3 3 4 1972 59 8 16 10 5 2 1973 50 22 16 3 4 5 1974 75 5 11 3 4 1 1975 63 14 22 2 0 0 1976 57 20 6 14 4 0 1978 49 24 22 0 2 2 1979 27 40 17 8 2 6 1980 40 36 15 4 1 4 1981 49 29 10 7 1 5 1982 55 25 8 6 1 6 1983 70 16 4 4 0 6 1984 75 9 4 8 0 3 1985 48 29 4 13 5 1 �115 Table 3. Continued Year Mallard Teal 1986 60 23 6 1987 52 25 1988 62 1989 Pintail Gadwall Shoveler Redhead 9 2 2 9 8 6 0 20 0 11 5 2 57 6 9 18 9 0 1990 64 9 3 20 3 0 Means 60 17 11 7 3 2 �116 between mallard nesting density on MVNWR and the mallard breeding population surveyed in the SLV (Fig. 6). Variability in the data are probably caused by relative differences .inwater conditions between the MVNWR and the SLV. Most mallards are resident year round in the SLV, (Szymczak 1986) and are therefore partially dependent on wintering conditions in just 1 region. This same relationship would not be expected for the more migratory species because many migrate out of the SLV after the survey and do not winter in the SLV. Nevertheless, refuge nest density, heavily influenced by mallards, is only a weak indicator of the annual breeding population in the SLV. Total numbers of breeding pairs have declined in the SLV but remained relatively stable at the MVNWR (Fig. 7); particularly for mallards (Fig. 8). Thus, the refuge is important in maintaining local duck populations. There is no apparent shift to MVNWR as habitat was reduced elsewhere in the SLV, merely a reduction in numbers valley-wide. Szymczak (1986) believed that reduced habitat in the SLV was caused by the reduction of flood irrigation, which create wetlands from runoff. The relationship between North American breeding pair surveys (U.S. Fish and Wildlife Service 1989) and the SLV breeding pair survey show low correlation for either mallards, total ducks, or total species other than mallards (rZ - 0.149, 0.187, and 0.099 respectively). Thus, the SLV breeding populations evidently fluctuates relatively independent of the North American population surveyed. Water Early water, defined as water applied to wetland units before 1 April, is needed to attract nesting ducks to the MVNWR (Schroeder et al. 1976). The MVNWR staff secured increasing amounts of water for early water applications (Fig. 9). Valley conditions (as indexed by Rio Grande River water), however, are more susceptible to the natural variations in precipitation (Fig. 10). Figure 11 shows the water by source for the totals given in figure 9. Vegetation Composition at MVNWR The MVNWR, which totals 13,912 acres (not included are unit 12, or units 13 and 19 west of the Monte Vista Canal), was classified into 697 polygons for GIS analysis. Nine polygons (1,506 acres) were not surveyed (generally agricultural fields). Five additional polygons (88 acres) were county roads between units and the Empire Canal. These 14 polygons were removed from consideration. Of the remaining 683 polygons important to nesting ducks, 513 (75%) were single-feature or single-vegetation patches. The remainder were patches consisting of 2 or more species in a patch. All areas (except the 591 acres of open water and the non-surveyed areas) were considered as habitat available for nesting, because ducks are known to nest on dikes, ditch banks, and near buildings. Accordingly, total area available to nesting ducks was 11,727 acres (18.3 mi2, excluding unit 12, units 13 and 19 west of Monte Vista Canal, all non-surveyed areas and open water bodies). There were 11 types of vegetation and transition type associations (4 or more dominant species in 1 patch Table 4). Even though there were 71 combinations of these types, the majority of polygons could be delineated into single-species patches unless they were extremely heterogenous. A total of 772 acres (146 polygons, 6% of the surveyed refuge) did not contain vegetation and were classified as: �117 Table 4. Vegetation categories Common name Scientific Baltic rush Juncus GreasewoodRabbitbrush Sarcobatus vermiculatus, Chrysothamnus and acreage name balticus on the MVNWR. a,b Acreage % of available 5,967 48.4 3,577 29.0 595 4.8 578 4.6b spp. Saltgrass Distichlis stricta Grasses Several Cattail Typha latifolia 424 3.4b Spikerush Eleocharis macrosachya 149 1. 2b Bulrush Scirpus 59 0.4b Sedge Carex spp. 39 0.3b Weeds Several spp. 36 0.3 Transition 4+ spp/patch 44 0.3 spp. validus Foxtail Hordeum jubatum 3 0.0 barley arable does not show water, roads, and park~ng areas. Values are rounded the nearest acre. bExtremely heterogenous patches cause less dominant species to be under represented compared to dominant species (mainly bullrush and cattail). to Nest Success Nest success, defined as the percentage of nests that hatch at least 1 egg, has fluctuated widely at MVNWR over time but has always been relatively high (~ - 49.4%, SE - 9.5, n - 26) for all years averaged over all species. The lowest recorded success was 27% in 1978 (following the drought years); the highest was 72% in 1966. The mid- and late-1960's saw widespread use of strychnine as a means of predator control at MVNWR (a yearly success table is given later when success is compared with management treatments). Causes of nest failure were: Cause of failure Percent Range (%) lPredation 25.8 9.2 to 43.6 Flooding 4.9 0.0 to 18.0 Desertion 10.6 3.3 to 27.0 Unknown 10.8 0.0 to 32.0 �us Table 5. Availability and nest site selection for all duck nests recorded at MVNWR,. 1964-1990. Values are heavily influenced by mallards. Non-surveyed areas excluded. Area of Total when Cover 11 when II when II when available sole combined dominant and subdominate habitat species but the (%) (%) dominant Baltic-Rush Greasewood Saltgrass Cattail Grass spp. Weeds Spikerush Sedge Unidentified All other 48.4 29.0 4.8 3.4 4.6 0.3 l.2 0.3 2,582 295 31 84 78 74 57 51 62 226 324 103 10 68 55 6 6 0 0.3 2,808 619 134 94 146 129 63 57 62 44 (67.6) (14.9) (3.2) (2.3) (3.5) (3.1) (l.5) (l.4) (l.4) (l.1) Table 6. Species use of nest cover at MVNWR 1964-1990a. percent of nests found in each major cover. 341 17 128 74 48 37 74 60 10 Values represent Mallard Gadwall Teal Species Pintail 66.3 59.8 73.9 58.2 15.6 19.5 6.9 24.2 3.1 0.0 l.2 0.6 Sa1tgrass Grasses 2.3 l.6 4.8 6.7 3.1 4.8 6.6 2.8 8.6 Spikerush Weeds l.5 0.4 * 3.2 * l.1 0.9 2.4 3.5 6.0 * 0.7 * 3.6 2.6 2.4 Cover type Baltic rush Greasewood Cattail * Shoveler Redhead * 70.7 74.7 * 2.6 * * * 9.6 5.1 6.0 * 5.1 0.0 * 2.4 * * All 4.5 4.3 2.6 2.7 8.0 * 2.4 * Others 4Aster1sks represent range ot h1gh and low use spec1es tor each vegetat1on. Only primary vegetation is represented. �119 The number of nest failures from unknown causes fluctuated widely each year. This annual variability reflects partly on the nest searcher's willingness to carefully examine a destroyed nest. Because of fluctuations in "unknown" failures, variation in annual success, and small sample sizes I have not reported annual rates of nest success. Success for all species across all nests and years was 52.4% (2,179 successful nests/4,156 total) Individual species' success varied little (mallard were 54.2% successful, gadwall 63.7%, teal spp. 54.5%, pintail 57.6%, shoveler 56.0% and redhead 55% successful). Success of 520 unknown nests was lower (~- 31.9%), probably because destroyed nests could not always be identified to species. The result, however, is that individual species' success are biased upwards. When the different species have "unknown" nests reapportioned based upon overall species composition, and a 31.9% success rate applied to those "unknown" apportionments, success declines slightly (mallard 51.4%, gadwall 59.8%, teal spp. 51.7, pintail 54.4%, shoveler 52.9%, and redhead 52.5%). Chi-square tests for significant differences between species or between species and overall success showed no difference. Gadwall, the species with the largest difference in nest success, had a X2 P value of 0.082. Management activities Grazing. - Grazing by domestic cattle was used to manipulate nesting habitat at MVNWR throughout the study period under three grazing schedules. The objective of the grazing program was to open dense vegetation mats and increase stand vigor (Melvin T. Nail, Pers. Comm.). First, from 1964-1976, dormant season grazing was allowed after the nesting season (usually after September 15) through early winter (usually before December 31), with only minor variability in these dates. Almost all units were grazed annually. Second, from 1976-1987, dormant season grazing was continued but individual units were placed on a 3-year, rest-rotation cycle. There was a reduction in total ADM during the rest rotation period, however, there was an increase in grazing intensity on average over the area actually grazed (Fig. 12) in a particular year. A third period began in 1988 with most units grazed as described for 1976-1987, but others were changed to short-term, high-intensity, growingseason grazing requiring units be subdivided into smaller cells. Short-term, high-intensity grazing has a variety of objectives; primarily this program is used at MVNWR for weed control and to reduce residual cover. This program was expanded and by 1990 included all or a portion of 7 units. Appendix G reports grazing intensity (ADM/acre) for each year and unit, however grazing density is difficult to access in the multi-cell units because only portions were grazed and cattle rotated; those values are omitted in the Appendix. This third period was in a state of constant change during 1988-1990 as the new grazing program was expanding. During 1964-1976, an evaluation of grazing effects on nest densities was impossible because the units very rarely went ungrazed (most were always grazed), thus no control exists for comparison. The second rest-rotation period, however, allows for a critical evaluation of nest density response immediately after, and 2 nesting seasons following grazing. The rest-rotation schedule (1976-1987 and partially continued to 1990) was used on 19 units included in the transect nest survey (Units 5, 12, 13, 23, 24 and year 1976 are excluded because they were not grazed, partially surveyed for nests but grazed completely, or data were unavailable). No nest survey was done in 1977 �I-' N 7,000 o 1----------------------- 6,000 1 5,000 :E ::> -c 4,000 3,000 2,000 1,000 o 64 66 68 70 72 74 76 78 Year Fig. 12. Annual grazing totals (AUM) MVNWR 1964-1990. 80 82 84. 86 88 90 �121 thus nest densities are unavailable, and units changed to the third grazing schedule are also omitted from the analysis after they were managed under the short-term, high-intensity grazing system. It was known by the mid-1960's that the number of duck nests varied substantially among units and years. Thus for the analysis, units and years were treated as class variables and estimated nest density (D) was regressed on grazing intensity (I) recorded as AUM/acre, and sub-period (5). Sub-period denoted either the 1st, 2nd, or 3rd nesting season following a graze cycle in the 3-year rest-rotation grazing schedule (i.e., the values of the variable sub-period were 1, 2, or 3). The analysis of the effect of grazing on the density of duck nests was based on the following regression model: E(D~)- b~ + b1(i) + b~(j) where: + bl(1) + bi(5~) + €~ i-year - 1977-1990 (grazing occurred in 1977, but no nesting survey was conducted that year). j - unit 1,2,3,4,6,7,8,9,10,11,14,15,16,17,18,19,20,21,22. bo - intercept b; and b4 - partial regression coefficients. b~ - vector of partial regression coefficient for the 14 units. b~ - vector of partial regression coefficient for the 19 years. €i1 - error terms, assumed to have mean of zero, independent and constant variance. Grazing intensity (Appendix H) was a continuous independent variable. Clearly, if grazing increased nest density the following year, then b3 would be positive; however, if grazing intensity decreased nest density thefollowing year, then b3 would be negative. The null hypothesis of no effect of grazing is b3 - O. Our ~ priori belief was that grazing intensity tends to decrease nest density and we treated the test of the null hypothesis as onesided. We explored a log-transformation of D, but found no improvement and, since it made interpretation more difficult, these results are not presented. Sub-period was treated as a continuous independent variable. The null hypothesis of interest was that b4 - 0 while the one-sided alternative hypothesis is that nest density increased each sub-period (year) following grazing (thus b4 > 0). The response of nest density to years of non-grazing was slightly nonlinear, thus 5~ was used in the model. There was significant variation in nest density across years and units (Table 7). In particular, the variation among units is very substantial. Grazing intensity significantly decreases nest density. Nest density increases each year after grazing is terminated. The regression model can be expressed for an average year and average unit by taking the mean of the partial regression coefficients (bl and b2, respectively). Then estimated density of nests per square mile (D) is expressed by the following equation: 5- 590 - 263.7(1) + 20.25(Sub2). This equation combines the average of the partial regression coefficients for years (b1) and units (b2) into the intercept term, thus bo - 590. This model, with 32 parameters, fit the data well (R2 - 0.60, residual MSE 406.5). We explored a log-transformation of D, but found no improvement and, since it made interpretation more difficult, these results are not presented. �122 Table 7. Analysis of variance results for nest density and the significance of four main effects. Source df Sum of s uares Mean s uare F value Pr > F Model 32 44,206,980 1,381,468 8.36 0.0001 year 12 6,535,762 544,646 3.30 0.0003 unit 18 36,120,180 2,006,677 12.14 0.0001 intensity 1 696,968 696,968 4.22 0.0415" Sub-period 1 854,070 854,069 5.17 0.0242" 175 28,920,182 165,258 Error 73,127,161 207 Corrected total "See text for one-tailed significance levels. The partial regression coefficient for grazing intensity (-263.7) indicates that nest density declined (t - 1.79, one-tailed P - 0.0367) as grazing intensity increased (Fig. 13). Nest density increased (t - 2.27, onetailed P - 0.01) each of the 3 years following termination of grazing. Examination of residuals from the model (Draper and Smith 1981) revealed that the 8 most extreme points (all positive) were associated with the 3 best units (units 3, 9, 18) in good years. Thus, the model failed to predict the density of nests in the best units in generally good years. We explored several squared and cubic terms in the model but found no significant improvement. We conclude that the model represents the variability in the data quite well. The regression model allows predictions of the decline in nest density caused by moderate grazing and how nest density increases each year following the termination of grazing. Expected nest densities 1-, 2- and 3-years following grazing for two grazing intensities (I - 0.5 and 1.0 ADM/acre) are: Expected nest densities (nest/mi2) by year following cessation of grazing Grazing intensity 1st year 2nd year 3rd year 0.5 478 539 640 1.0 347 407 509 It is difficult to predict the nest density for an average year and unit because no controls (units that were not grazed for 7-10 years) are available. However, without extrapolating beyond the available data, one can set I - 0 and predict nest density at the third year after grazing had been terminated, using: 5 - 590 + 20.25(32) - 772. This figure is probably too low, as the recovery in ne-stdensity probably would take >3 years. Using this estimate of 772 nests per square mile, nest �123 1000 >- -+- 900 (J) c <D 800 0 -+- 700 (J) <D Z 600 lJ <D 500 -+- 0 E 400 -+(J) w 300 1 200 0 0.5 1 1.5 Subperiod Grazing Intensity Fig. 13. Estimated duck nest density as a function of grazing intensity and the number of years following the termination of grazing (subperiod). �124 density is decreased 38% ([772 - 478]/772) the first nesting season after being grazed at 0.5 ADM/acre, and 55% the first nesting season after being grazed at 1 ADM per acre. Does the vegetation (primarily baltic rush) get too thick and matted for good nesting habitat? The extensive data at MVNWR suggest quite the opposite; ducks require heavy residual cover for nesting. Moderate, winter grazing on a 3 year, rest-rotation cycle has had a significant detrimental effect on the density of duck nests on the MVNWR. Even 3 years following the termination of grazing at 0.5 AUM/acre, the expected nest density is depressed at least 17% ([772 - 640]/772). It.is not clear if moderate grazing is beneficial if applied, for example, every 8 or 10 years. Nest density would decrease for at least 3 years following grazing, but perhaps there would be a long-term benefit in occasional grazing. Prescribed Burning. - Burning was not used as a habitat manipulation procedure until 1981. Often, prescribed burning followed grazing during years when a unit was grazed during the rest-rotation grazing regime. . Burns which were conducted in early spring prior to nesting were intended to clean a unit of residual cover. Caution should be exercised in evaluation of these data because they are confounded by grazing, were often incomplete, and because of small sample size. Ten prescribed burns have occurred at MVNWR, (some burns covered part of 2 units for a total of 14 treatments). Two more burns, 1 <25 acres, and 1 in a unrecorded unit, are not reported. Only 8 of the 14 treatments burned >50% of a unit, making an evaluation of treatment difficult (Table 8). No effort was made to evaluate treatments with <50% coverage. Evaluation of the 8 burns with >50% coverage showed that in 7 out of 8 burn treatments (88%), nesting density decreased from the previous year while during 5 of those 8 cases, refuge-wide nest density (burn units excluded) went up. This small sample of 8 burns appears to indicate that nest density is reduced the year of a burn. MVNWR has high densities of early nesting mallards which, combined with a short growing season would support the data suggesting that burning inhibits nesting directly after a burn. One year after burn treatments, 6 of 8 units had increases in nest density and 1 remained unchanged. On a refuge-wide basis, nest densities 1 year after burning increased in only 3 of 8 cases. These data suggest that a burn treatment has a negative effect the year of the burn but may be beneficial to nesting 1 year thereafter. �125 Table 8. Prescribed burning % burned Year Unit 4 9 19 14 15 17 3 treatments on the MVNWR, 1964-1990. ab % burned Year Unit 39 lOOC 1982 1983 4 18 47 60 1984 1984 28 1983 1984 6 100 100 1989 1984 1984 17 9 1984 10 42 48 75 33 .SAcreage burned was generally bIncomplete burning. CReported unit burns usually 8 estimated resulted as: "burned unit 9", assumed 73 1989 1989 50 72 1989 1989 by refuge staff. from greasewood to be a complete vegetation not burn. Predator control. - Predator management records revealed 3 separate periods of predator control effort during 1964-1990 (Table 9). Unfortunately, qualitative measures of predator control (person-days trapping, number of traps, number of bait stations) are essentially unavailable. In addition, the effect of these programs is likewise essentially unknown or unrecorded, because exact numbers of dead avian predators, skunk etc. were not always accurately recorded. Thus, only a very qualitative index to predator control can be deduced from the data presented. All available records were used in these analyses, however total numbers are not reported here. From 1964-1970, (period 1) nest predators were poisoned and trapped. Poison control made it difficult to quantify effect because animals may wander before death. This is especially true with avian predators, which are the predominate nest predators at MVNWR. Numeric records of trapped mammals were found for this period. Period 1 was probably the most effective of the 3 time periods because of the effectiveness of poison baits. From 1971-1980, (period 2) there were few records found concerning numbers of trapped mammals. Data were found that indicated extensive aerial gunning for coyote (Canus 1atrans) during this period. Poison control ceased at the beginning of period 2, but magpie bait traps were reported to be used frequently. Magpie nest destruction was also employed, but no numbers were recorded. The 1971-1980 period had a less aggressive predator control program compared to earlier years. In the third period, 1981-1990, predator management intensified. Predator removal was quantified and data were retained on file. Mammals and avian predators were trapped and shot at every opportunity. Predator control appears related with nest success (Fig. 14). Nest .success, however, is dependent on other variables in addition to predation. When only the nests predated is expressed as a percentage of total nests, predator removal has a noticeable effect (Fig. 15). The mean percent of predated nests of all failed nests during the three periods was 16.6, 33.7 and 25.1 respectively. Nest success varied among predator management periods �t-' N 0\ 80 Posion & active trapping .: \ \ Active trapping, avain & mammal 60 End of poison, decreased trapping / / ---... period 2 -, \ -. .•....• C ID () 40 LID n, 20 o 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 Fig. 14. Nest Success MVNWR all species 1964-90 Year �100 End of pOison, decreased tra~ // mean = 33.7% period 2 Active trapping, avain & mammal \ I~ / 80 = \ mean 25.1% • period 3 Poison & active trapping / 60 mean = 16.6% period 1 ~ c Q) o \... 40 Q) o, 20 o 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 Year Fig. 15. Percent of failed nests due to predators, all species, MVNWR 1964-1990 •..... N '-l �128 Table 9. Summary of predator control efforts on MVNWR, 1964-1990. specific records are on file at the MVNWR Control Period 1 Period 2 Period 3 Poison bait Magpie trapping Destroy magpie nests Mammal trapping Aerial coyote gunning Overall control effort yes no no yes yes High no yes yes limited yes Low no yes some yes yes Hf.gh" aProbably not as effective as period 1 when poison was used (F - 6.89, 2 df, P - .0045) with nest success during period 1 significantly greater than during period 2. Period 3 was not significantly different from either period but had greater success than period 2. Three important factors must be considered when evaluating these data. First, there was no survey of predator levels in conjunction with predator control. Second, the "unknown" nest failures fluctuated greatly throughout the survey period. Most certainly, some predated nests were recorded as "unknown" cause of failure. For example, if all eggs were removed from the nest area by a predator and the nest bowl could not be located, then the nest would probably have been recorded as unknown resulting in a negative bias of predation rates. Third, a regression of nest success on nest density (Fig. 16) yields a positive relationship (rZ of 0.309, P - <0.01), indicating possible that nest density may increase faster than predator numbers. It is possible that the "surplus" nests are predated at a lower rate. Either scenario complicates evaluations of the effects of predator control. A more detailed examination is necessary to address this issue. Data provided by the nest survey, and the qualitative data collected on predator control (especially during the second period), are insensitive measures of this treatment effect. Haying Program. - In 1964, hay was cut on units 4, 7, 14, 20, 22, and 23 (Bill McDermith, MVNWR Pers. Comm.) The amount hayed was 14.4% of the refuge (1,665 acres). Only portions of each units were cut and specific areas actually cut within these units is not available. The program was reduced, and finally eliminated by 1977 (Fig. 17). Nest density' in units that were hayed was compared to refuge-wide nest density (hayed units removed). Mean nest density for the units hayed during the first 7 years (1964-1970) of the hay program was 257 nests/miz. During this same period, refuge-wide nest density, less hayed units, was 599 nests/mi2. Additional analyses of these same hayed units for the period 1984-1990 (a later 7-year period with no haying) show a mean density of 361 nests/mi2• Refuge wide nest density, less the 6 units, for the same period was 705 nests/mi2. Chi-square tests for difference between units hayed during active cutting vs. non-cut units for the 2 time periods are not appropriate because the density values represent means, not frequency data. However, analysis of �80 ~------------------------------------------------~ o ro U) I 0 60 . ~ 0 ~ it 0 Z 40 0 0 u UU~ 50 o 0 0 0 O~ :.._;..;.;;0 0 30 20 t 0 0 . 100 200 Nest density 300 400 500 (nests I sq.rnl.) Fig. 18. Success In relatIon to nest density, MVNWR 1964·1990. •.... N \.0 �•..... w o 2,000 '"0 r---~~-----------------___;_' 1,500 Q) iO' .c: Q) en 1,000 CO Q) 'o « 500 o 64 65 66 67 68 69. 70 71 Year 72 73 74 75 76 rt No acreage hayed data available 1965,1973-74. Fig. 17. Acreage and percent hayed on the MVNWR, 1964-1977 �131 tall dense cover represents a behavioral deterrent as well as physical barrier to crows hunting on foot, thus predator management may be partially controlled by vegetation manipulation. Schranck (1972) and Dwernychuk and Boag (1972) also noted that predation was less in dense cover. Duebbert and Kantrud (1974) determined that predator control efforts made a significant contribution in areas with high nest density. However, predator removal in areas which do not have an abundance of prime nesting cover will not result in greatly increased duck production. Predators quickly reoccupied habitats when control programs ceased. Lastly, Picozzi (1975) demonstrated that marked nests were predated at a higher rates than unmarked nests, thus predation at MVNWR may be somewhat inflated. This was not studied at MVNWR but demonstrated elsewhere (MacInnes and Misra 1972). Clearly, predator management can be effective in some circumstances. However the amount of benefit and therefore the cost-effectiveness, varies among habitats and has not been quantified at MVNWR. Kirsch (1969) stated "that grazing should be discontinued as a regular land-use practice on areas managed primarily for upland nesting ducks and upland game birds". Despite conflicting opinion to the contrary (Kantrud 1986), results of our analyses of grazing on the MVNWR support Kirsh's view of the detrimental effects of grazing. Grazing under the dormant season, 3-year rest-rotation system employed in the past had dramatic, negative effects on nesting ducks. Continued use of this grazing system is not recommended. Burning treatments at MVNWR seem to indicate a decrease in nest density the year of a burn followed by an increase the following year. Bouffard et al. (1987) discussed burn treatments and concluded they should be used sparingly, only in "small blocks", and that nesting may be affected longer than just the year of the initial burn for overwater-nesting species. Burn treatments, however, were again never experimentally controlled or in isolation from other treatments. The small sample of large-scale burn treatments also limit evaluation. The MVNWR is subject to many external factors that may affect nest density. It has been speculated that good SLV water conditions could possibly redistribute ducks from the refuge and reduce density regardless of management activities. Johnson and Grier (1988) pointed out that by virtue of their mobility, ducks have many options for selecting habitat in which to breed. They proposed 3 settling patterns which determine distribution of nesting ducks. The species evaluated at MVNWR (with the lessor exception for pintail and teal spp.) were shown to have homing-inherent settling patterns. Therefore these species may move on if nesting conditions are inadequate. Johnson and Grier also demonstrated that homing to a successful area has reproductive advantage over pioneering. This implies that changing habitat conditions which force ducks to new areas may result in lower success rates. The composition of nesting duck species fluctuated over time. The SLV breeding pair survey shows a decrease in the number of ducks valley-wide. However, the refuge counts remain more consistent over the same time period. This may suggest that duck populations and hence nesting densities in the valley are related to relative water conditions. Species composition data show general trends of an overall increase in gadwall nests but a decrease in pintail. Mallard nest numbers declined during a dry years in the mid-1970's whereas teal species increased. Neither group has changed much when viewed over the entire period. Shoveler and redhead nest densities show no trend and remain relatively constant over time, however sample sizes are low for these species (131 and 121 annually, respectively). Duck nests on MVNWR have a high success rate (52.4% for all nests �132 in high densities (26 year ~ _ 422 nests/mi2 for all units, range - 27 to 1366 nests/mi2). Higgins (1977) evaluated success in untilled and tilled agricultural land in the Dakotas. He found success rates of 25% and 17%, respectively, and reported other work with 39% and 33% nest success. He found a mean of 8.0 nests/mi2 (3.1 nests/km2) for the 2 types of habitat. Martz (1967), comparing mowed vs. unmowed lands, reported a high of 268 nests/mi2 (4.2 nests/lO acre) in the best year in the unmowed areas. Duebbert and Lokemoen (1976) studied duck nesting in undisturbed grass-legume cover in north central South Dakota and found a three-year density of 121 nest/mi2 (47 nests/km2). Duebbert and Kantrud (also from study in northcentral South Dakota) found density as high as 775 nests/mi2 (299 nests/km2) in predator-controlled idle lands. Nest success in their work ranged from 51% to 92% for agricultural areas without predator control and idle lands with predator control respectively. Kirsch (1969) reported density in grazed vs. ungrazed areas of a North Dakota nest study to be 108 and 179 nests/mi2 (0.17 and 0.28 nests/ A.), respectively. Percent hatched in that study was 14% for grazed and 28% for the ungrazed areas. The MVNWR has a history as an area on which to apply unproven management practices in an experimental framework. The refuge continues to have this experimental potential because of the transect survey system and individual management units. Future management experiments that evaluate habitat treatments should be encouraged on the MVNWR. studied) and also occur MANAGEMENT RECOMMENDATIONS Because nesting success and nest density are already very high, additional management aimed at improving either parameter will likely result in limited success. One exception is the elimination of grazing, which would result in an immediate overall increase in duck nesting densities. In addition, managers should focus on increasing nest density in low density units through habitat enhancement. Monitoring, through proper evaluation, should precede and follow any management treatment to manipulate nesting qualities or vegetation characteristics at MVNWR. There are surfacing issues facing conservation agencies dealing with maintenance of biodiversity. MVNWR has the opportunity to become a hub for the evaluation of management activities on all species. Many miles of transect have been surveyed for evaluating duck production. This system, if maintained and or expanded, could also develop baseline information for other species. Management for optimal duck production mayor may not favor other wildlife. MVNWR has both the potential and the responsibility to fully understand the benefits and/or consequences of management practices. The Colorado Statewide Waterfowl Management Plan (1988) identifies limited funds for new land purchases for conservation as a problem facing ducks in Colorado. Steps have been taken to raise additional funds, such as the new state waterfowl stamp and the MARSH program. MVNWR has the potential to serve as an example for future land development and management. The transect system at MVNWR should be included in all future management activities to aid in the evaluation of implemented goals and objectives. The quality of the data was diminished when even-numbered transects were removed. However the survey is still good and worth pursuing. With minimal efforts such as including nests at increased distances from transect centerline~ incorporating program DISTANCE, and including other variables or species, the survey could be improved upon. Better analysis of management practices on �133 vegetation should also into refuge management evaluated. Additional conducted as part of a be included. Experimental design could be incorporated planning so that management activities could be recommendations will follow through work being separate contract. LITERATURE CITED Anderson, D. R. and R. S. Pospahala. 1970. transect studies of immotile objects. 146. Correction of bias in belt J. Wildl. Manage. 34:141- Balser, D. S., Dill, H. H. and H. K. Nelson. 1968. Effect of predator reduction on waterfowl nesting success. J. Wildl. Manage. 32:669682. Borland International. 1990. Quattro Pro Version 2.0 Users Guide. Borland International, Scotts Valley CA. 800pp. Bouffard S. H., Sharp, D. E. and C.C. Evans. 1987. Overwater nesting by ducks: A review and management implications. Paper presented at 8th Great Plains wildlife damage control workshop. Rapid City, S.D., April 27-30., 1987. Burnham, K. P., D. R. Anderson and J. L. Laake. 1980. Estimation of density from line transect sampling of biological populations, Wildl. Monogr. 72. 202pp. Campbell, J. B. 1987. Introduction to remote sensing. New York, NY. 55lpp. Gilford Press. Colorado Division of Wildlife. 1989. Statewide Waterfowl Management Plan. Colo. Div. Wildl., Migratory Game Bird Program Unit. Ft. Collins. 99pp. Doty H. A. and A.J. Rondeau. 1987. Predator management to increase duck nest success. Paper presented at 8th Great Plains wildlife damage control workshop. Rapid City, S.D. April 27-30., 1987. Draper, N. R. and H. Smith. 1981. Applied Regression Analysis. 2nd. ed. John Wiley & Sons. New York. 709pp. Duebbert, H. F. and H. A. Kantrud. 1974. to land use and predator reduction. Upland duck nesting related J. Wildl. Manage. 38:257-265. _________ , J. T. Lokemoen. 1976. Duck nesting in fields of undisturbed grass-legume cover. 40:39-49. ____________ , and D.E. Sharp. 1983. Concentrated nesting of mallards and gadwalls on Miller Lake Island, North Dakota. J. Wildl. Manage. 47:729-740. Dwernychuk, L. W. and D. A. Boag. 1972. ducks nests from egg-eating birds. How vegetative cover protects J. Wild. Manage. 36:955-958. �134 Hammond, M. C. and D. H. Johnson. 1984. Effects of weather on breeding ducks in North Dakota. U.S. Fish Wildl. Serv., Tech. Rep. 1. l7pp. Higgins K. F. Dakota. 1977. Duck nesting in intensively farmed areas of North J. Wildl. Manage. 41:232-242. Johnson, D. H. and J. W. Grier. 1988. Determinants of breeding distributions of ducks. Wildl Monogr. 100:1-37. Kantrud, H. A. 1986. Effects of vegetation manipulation of breeding waterfowl in prairie wetlands-a literature review. U.S. Fish and Wildl. Serv., Fish Wildl. Tech. Rep. 3. l5pp. Kirsch, L. M. 1969. Waterfowl production in relation to grazing. J. Wildl. Manage. 33:821-828. Monte Vista National Wildlife Refuge. 1964-1990. Annual Narrative Reports and miscellaneous files. Alamosa National Wildlife Refuge Files. Alamosa, Co. Enright, C. A. 1971. An analysis of mallard nesting habitat on the Monte Vista National Wildlife refuge. M.S. Thesis, Colorado State Univ., Ft. Collins. ll3pp. Labisky, R. F. 1957. Relation of hay harvesting to duck nesting under a refuge-permittee system. J. Wi1d1. Manage. 21:194-200. MacInnes, C. D. and R. K. Misra. 1972. Predation on Canada goose nests at McConnell River, Northwest Territories. J. Wild1. Manage. 36:414-422. Martz, G. F. 1967. Effects of nesting cover removal on breeding puddle ducks. J. Wildl. Manage. 31(2):236-247. Picozzi, N. 1975. 39:151-155. Crow predation on marked nests. J. Wildl. Manage. Robinson, G. w. 1971. Vegetation and physical factors influencing waterfowl production. M.S. Thesis, Colorado State Univ., Ft. Collins. l48pp. SAS Institute Inc. 1987. SAS/STAT user's guide release 6.0. SAS Inst., Inc., Cary, NC. 1028pp. Schranck, B. w. 1972. Waterfowl nest cover and some predation relationships. J. Wildl. Manage. 36:182-186. Schroeder, L. J. 1973. Effects of invertebrate utilization on waterfowl production. M.S. Thesis, Colorado State Univ., Ft. Collins. 44pp. Schroeder, L. J. et al. 1973. Effects of early water application on waterfowl production. J. Wildl Manage. 40(2):227-232. �135 Sugden, L. G. and G. W. Beyersbergen. 1987. Effect of nesting cover density on American crow predation of simulated duck nests. J. Wildl. Manage. 51:481-485. Szymczak, M. R. 1986. Characteristics of duck populations in the intermountain parks of Colorado. Colorado Div. Wi1d1., Div. Rep. 6. 13pp. U.S. Fish and Wildlife Service, and Canadian Wildlife Service. Status of waterfowl and fall flight forecast. 39pp. 1989. U.S.D.l. Fish and Wildlife Service. 1986. Birds of the Alamosa Monte Vista National Wildlife Complex. GPO 848-805., Alamosa, Colo. 8pp. Prepared by: ~ £ ~ g;man Jame~.R Wildlife Researcher C �136 Appendix A. Individual unit summaries of acreage, and nesting importance, MVNWR for the period 1964-1990.~ Unit Tot. A. Non surveyed Open water Available acerage % of tot. avai1able (A) % of nests found (B) Nest density 0 (B)/(A) 1 291 0 34 257 2.1 2.5 569 1.165 2 136 0 10 126 1.1 1.0 495 0.946 3 901 0 0 901 7.6 12.6 1000 1.647 4 641 0 1 640 5.4 3.0 366 0.545 5 625 322 0 303 2.6 0.1 27 0.055 6 625 0 44 581 4.9 6.8 1164 1.379 7 1052 0 38 1013 8.6 8.6 330 0.999 8 394 0 27 367 3.1 4.5 704 1.438 9 887 0 2 865 7.4 19.8 1540 2.677 10 629 0 18 611 5.2 3.5 412 0.670 11 611 0 3 608 5.1 2.1 194 0.399 14 655 132 51 473 4.0 2.4 301 0.582 15 599 0 94 504 4.3 5.1 519 1.185 16 625 0 40 585 4.9 2.3 235 0.458 17 602 45 83 474 4.0 5.3 570 1.303 18 661 91 19 550 4.7 12.3 1366 2.627 19 626 0 52 573 4.9 1.8 200 0.369 20 637 186 3 448 3.8 1.1 156 0.296 21 641 0 1 640 5.5 2.3 222 0.414 22 620 31 1 589 5.0 1.7 172 0.335 23 321 210 1 110 0.9 0.2 140 0.257 24 644 66 68 510 4.3 0.9 142 0.210c aUnits 12 and 13 are not surveyed. All acreage values are rounded. bDensity value is the mean of annual densities for the unit over the period of record. See Appendix E for annual refuge density. CUnit 24 was not sampled until 1981, no. nests is biased low. �137 Appendix B. Numbers of nests found and nest chronology MVNWR 1964-1990. year 1977 is excluded. Year No. July nests removed from survey statistics 1964 0 261 41 1965 4 212 40 1966 7 260 61 1967 57 244 43 1968 2 315 42 1969 4 230 57 1970 6 229 45 1971 3 114 60 1972 1 127 52 1973 6 239 44 1974 0 109 40 1975 3 65 15 1976 0 95 50 1978 0 55 33 1979 0 53 55 1980 0 89 75 1981 0 104 47 1982 4 110 54 1983 22 114 23 1984 10 150 37 1985 0 152 55 1986 1 197 39 1987 0 262 45 1988 0 150 40 1989 0 130 53 1990 0 90 39 Average "Does No. found, May & Percent found June searches in May not reflect effort changes 160a 45.6 The �l38 Appendix C. Annual number of unidentified nests found during nest searches on MVNWR, 1964-1990 that were reapportioned to other species. Year No. unknown Percent unknown Year No. unknown Percent unknown 1964 62 24 1978 14 25 1965 19 9 1979 5 9 1966 54 21 1980 4 4 1967 31 13 1981 1 1 1968 70 22 1982 6 5 1969 60 26 1983 1 1 1970 62 27 1984 1 1 1971 16 14 1985 6 4 1972 20 16 1986 6 3 1973 35 15 1987 14 5 1974 17 16 1988 0 0 1975 6 9 1989 1 1 1976 9 9 1990 0 0 �139 Appendix Forms used by the refuge to calculate D. ... - production on the MVNWR. , --·l''O'=-,........fzf'i'!~ .••. a,.) a.', UI C_tt. ••••1. r... r... 1u.!W__ 1_ ~41_~" ...t. -- ... )1 . ·l.'.••.' ':~, c.,. ". ...,•.., • Z 0. • _If..o:''' ~.11_ ~.i.!l.(C.l., i- .---F!;"'~m' .,.~ ". ~fcl·:.,~~:·E..••••. ,n Ultn-- '" ·-m!'!.. ..+n (.j C. c_,. _. (wl.' Ib,UUL I,.C.,. :£ ".l4IIt' la (~'.~~~: lR ••••• 5) (;'1.' f-l'. toU,l_ __ tlR'.U c:a.tw.11 I . '~e••l1n CIR •• T•• 1 CI.~ I T•• I ...~. _. _. ~.d~ •• ' ._- - , I I I I - TeT~1. I ce.t (Cll. • v T•• I Tr•••• ca. 1•. , (~~~ (~I ~C~!i. ~~, (~rea r.,., - , Ul' :Ia'•••l •• ~ IU' ....•...• ,. U~I U:J (U' :Ie. I'ooc:&llltca t •••• r",!., U" DTt:~ .• ''''C.a~ ~ u•• C:.'••l, .. (C.~, '!'~'.\;.' : I I ! T.ol ~j_ i ~ !dI' I I T~It. Cas Cr..... I T•• l •••~tI"'" h.UM •••••• 4 ... ..• .,,, I ....••'c•••• ,. ....r... ,...,... ......•. ••• .._.i.. .•.. '_~l ~~~,." . t.~. ,... .. f---._. ~-1-----,-, - -_. .-.. ±= _._" . I - ..._t. ••••• 11M f.'11 a.•••• ,. c.•• IIJ:'l.1l_ l'l!:s1.lU •......• - ••••••• (U) I,. !:IlJM.. ••;;:;;Cl';'.~-':~ ·iir-rr;:~·M.· .•~ 1••••••• , ".t. (SOl .JWIl... _LI I ,,'.uac imW._ I-- .t ! I .JIet." v,..,,, ••• - I I -r- __L___L =t' I- - i i-- I. ; .1- -..~ ! _j__ . i-- -4- ._1-- • I 1- I =ti---1._" �140 Appendix E. Summary of survey data and estimated nest density for MVNWR from 1964-1990, 1977 excluded. Transect width (2w) Length of transects (L) No. of nests Estimated (n) value Estimated nest density 1964 16.5 323.6 261 0.144 306.7 1965 16.5 323.6 212 0.144 249.0 1966 16.5 323.6 260 0.144 305.4 1967 16.5 323.6 244 0.144 286.7 1968 16.5 323.6 315 0.144 370.1 1969 24 170.6 230 0.107 380.9 1970 24 170.6 229 0.107 379.3 1971 24 80.7 114 0.107 398.7 1972 24 161.6 127 0.107 222.1 1973 24 161.6 239 0.107 417.9 1974 24 161.6 109 0.107 190.6 1975 24 161.6 65 0.107 113.7 1976 24 161.6 95 0.107 166.1 1978 24 161.6 55 0.107 96.2 1979 24 161.6 53 0.107 92.7 1980 16.5 161.6 89 0.144 209.4 1981 16.5 168.8 104 0.144 234.2 1982 16.5 168.8 110 0.144 247.7 1983 16.5 168.8 114 0.144 256.7 1984 16.5 168.8 150 0.144 337.8 1985 16.5 168.8 152 0.144 342.3 1986 24 168.8 197 0.107 329.6 1987 24 168.8 262 0.107 438.4 1988 16.5 168.8 150 0.144 337.8 1989 16.5 168.8 130 0.144 292.8 1990 16.5 168.8 90 0.144 202.7 Year Average f(O) 277 .1 �141 Appendix E. Summary of survey data and estimated nest density for MVNWR from 1964-1990, 1977 excluded. Year 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 Average Transect width (2w) Length of transects (L) No. of nests (n) value 16.5 16.5 16.5 16.5 l6.5 24 24 24 24 24 24 24 24 24 24 16.5 16.5 16.5 16.5 16.5 16.5 24 24 16.5 16.5 16.5 323.6 323.6 323.6 323.6 323.6 170.6 170.6 80.7 16l.6 16l.6 16l.6 16l.6 16l.6 16l.6 16l.6 16l.6 168.8 168.8 168.8 168.8 168.8 168.8 168.8 168.8 168.8 168.8 261 212 260 244 315 230 229 ll4 127 239 109 65 95 55 53 89 104 llO ll4 150 152 197 262 150 130 90 0.144 0.144 0.144 0.144 0.144 0.107 0.107 0.107 0.107 0.107 0.107 0.107 0.107 0.107 0.107 0.144 0.144 0.144 0.144 0.144 0.144 0.107 0.107 0.144 0.144 0.144 Estimated f(O) Estimated nest density 306.7 249.0 305.4 286.7 370.1 380.9 379.3 398.7 222.1 417.9 190.6 ll3.7 166.1 96.2 92.7 209.4 234.2 247.7 256.7 337.8 342.3 329.6 438.4 337.8 292.8 202.7 277 .1 �146 AppendixH. Densityof cattle,AUM/acrefor grazedunits MVNWR 1964-l990ab• Unit Year 1 2 3 4 567 1964 0.7 1.2 0.6 0.3 0.3 0.4 1965 0.0 0.0 0.4 0.2 1966 1.2 0.8 0.7 1967 0.0 0.8 1968 0.8 1969 8 9 10 0.3 0.6 0.5 0.2 0.6 0.2 0.4 0.4 0.4 0.0 0.0 0.0 0.5 0.0 0.4 0.7 0.0 0.7 0.1 0.6 0.5 0.2 0.4 0.7 0.0 0.8 0.4 0.1 0.0 0.5 0.3 0.5 0.3 0.0 0.9 1.0 0.5 0.6 0.0 0.6 0.5 0.4 0.2 0.0 1970 0.4 0.8 0.8 0.2 0.0 0.4 0.2 0.3 0.9 0.0 1971 0.4 0.6 0.7 0.2 0.0 0.5 0.2 0.3 0.7 0.0 1972 0.6 0.5 0.6 0.6 0.0 0.3 0.2 0.2 0.6 0.8 1976 0.6 0.5 0.3 0.5 0.4 0.7 0.1 0.2 0.3 0.4 1977 0.2 0.1 0.1 0.0 0.1 0.1 0.1 0.1 0.0 0.0 1978 0.0 0.1 0.0 0.0 0.1 0.1 0.1 0.1 0.0 0.0 1979 0.8 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.5 0.0 1980 0.0 0.0 0.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1981 0.0 0.8 0.0 0.0 0.4 0.0 0.4 0.4 0.0 0.6 1982 1.2 0.0 0.0 0.0 0.0 0.8 0.0 0.0 0.8 0.0 1983 0.0 0.0 0.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1984 0.0 0.0 0.0 0.3 0.3 0.0 0.3 0.0 0.0 0.3 1985 1.6 1.0 0.0 0.0 0.0 0.5 0.0 0.5 0.8 0.0 1986 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1987 0.0 0.0 0.0 0.3 0.4 0.0 0.3 0.0 0.0 0.3 1988 1.8 0.9 0.0 0.0 0.0 0.6 0.0 0.4 0.7 0.0 1989 0.0 0.0 0.7 0.0 0.1 0.0 0.0 0.0 0.0 0.0 1990 1.1 0.0 0.4 0.8 0.2 0.3 0.0 0.0 0.2 (continued) c �147 Appendix H. (continued) Unit year 11 14 15 16 17 18 19 20 21 22 23 64 0.4 0.4 0.2 0.7 0.6 0.7 0.3 0.3 0.6 0.9 0.2 65 0.4 0.5 0.0 0.5 0.4 1.3 0.2 0.9 0.7 0.1 0.0 66 0.5 0.5 0.2 0.6 0.4 1.0 0.2 0.5 0.8 0.5 0.4 67 0.5 0.5 0.2 0.6 0.4 1.0 0.1 0.6 0.8 0.7 0.0 68 0.6 0.5 0.2 0.5 0.5 0.3 0.2 0.5 0.7 0.4 0.0 69 0.8 0.5 0.3 0.5 0.4 0.0 0.3 0.6 0.8 0.2 0.1 70 0.8 0.5 0.2 0.6 0.3 1.1 0.6 0.6 0.8 0.6 0.3 72 0.8 0.5 0.2 0.6 0.2 0.9 0.3 0.2 0.8 0.3 0.2 72 0.8 0.5 0.2 0.6 0.2 0.8 0.2 0.5 0.8 0.5 0.* 76 0.3 0.3 0.2 0.5 0.2 0.4 0.0 0.4 0.2 0.2 0.5 77 0.1 0.2 0.0 0.0 0.1 0.0 0.0 0.2 0.0 0.1 0.0 78 0.1 0.0 0.0 0.0 0.1 0.0 0.* 0.2 0.1 0.1 0.0 79 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.5 0.0 0.0 0.0 80 0.0 0.3 0.3 0.5 0.0 0.8 0.0 0.5 0.0 0.0 0.0 81 0.4 0.0 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.8 0.0 82 0.0 0.0 0.0 0.0 0.0 0.0 0.8 0.0 0.9 0.0 0.0 83 0.0 0.4 0.4 1.0 0.0 0.8 0.0 0.8 0.0 0.0 0.0 84 0.3 0.0 0.0 0.0 0.0 0.0 0.7 0.0 0.0 0.9 0.0 85 0.0 0.0 0.0 0.0 0.5 0.0 0.0 0.0 1.2 0.0 0.0 86 0.0 0.3 0.3 0.9 0.0 0.5 0.0 1.2 0.0 0.0 0.0 87 0.4 0.0 0.0 0.0 0.0 0.0 0.9 0.0 0.0 1.1 0.0 88 0.0 0.0 0.0 0.0 0.4 0.0 89 0.1 0.2 0.2 1.0 0.0 1.2 90 0.2 0.0 0.0 0.0 0.0 0.0 aNo unit hvalues as 0.* data available 1973-75. rounded to nearest 0.1, values <0.05 ADM/acre but not 0 are recorded C---Reveals units where high intensity grazing paddock arrangement and cattle were rotated. was utilized in a multi- ��149 Colorado Division of Wildlife Wildlife Research Report September 1991 JOB PROGRESS REPORT State of __~C~o~l~o~r~a~d~o~ Project Work Plan _ Avian Research - Migratory Game Birds W-152-R-4 __l__: Job 20 Job Title: Development and evaluation of moist-soil management techniques in Colorado Period Covered: Author: 1 April 1990 through 31 March 1991 James K. Ringe1man Personnel: R. Brown, D. Ferrin, S. Hoover, T. Ostertag, J. Ringe1man, M. Szymczak, Colorado Division of Wildlife. ABSTRACT Wellington Wildlife Management Area, a 6,669 ha property owned and operated by the Colorado Division of Wildlife, was selected as the site for moist-soil experiments. A levee plow and water control structures were purchased in late winter, and the proposed site for impoundment construction was surveyed for grade by a professional engineer on 26 February 1991. Anticipated water depths in each impoundment were expected to range from 40 cm at the distal end of the impoundment to near 0 cm at the proximal end. Based on this engineering survey,S impoundments, each $0.5 ha in area, were constructed in March and April using 0.5 m high levees. A filling and drawdown schedule was established on 28 May, but ditchwater was unavailable until 1 June because of wet spring weather and resultant Lnsuf'f Lc Lent; call for irrigation water. Ditchwater was again unavailable in mid-June as early summer rains continued. After initially filling all impoundments on 1 June, it became apparent that the initial engineering of impoundment grades was in error, because water only accumulated for 3-6 m behind the distal levee at maximum capacity. Consequently, impoundments were effectively unusable for experimental purposes and no experiments were performed. The impoundment site will be re-examined for grade in fall and winter 1991 and a decision will be made whether to scrape and level the impoundments to enable continuation of the experiment, or whether to abandon the study. Prepared by: James K. Ringelman Wildlife Researcher C ��151 JOB PROGRESS Colorado State of Project No. Work Plan No. Job Title: Period REPORT Covered: W-152-R-4 Avian Research 1 Job No. Analysis of Mallard 1 September, Winter Game Birds 21 Banding 1990 - 31 March, - Migratory Data Collected in Colorado 1991 Personnel: M. Wotawa, D. Anderson, K. Burnham, Colorado Cooperative Fish and "Wildlife Research Unit; B. Wunder, Colorado State University; H. Funk, D. Hopper, M. Szymczak, J. Ringelman, Colorado Division of Wildlife. ABSTRACT During the winter of 1963-64 personnel from the state of Colorado began banding mallards in Eastern Colorado to assess the feasibility of managing mallards on a flock basis. They attempted to band 1000 mallards, 250 in each age and sex class, within 7 major winterfharvest concentrations in eastern Colorado. Banding continued until the early to mid 1980' s. Additionally, banding occurred in 1 major wintering area in western Colorado from 1973-82. A total of 128,211 banding and 11,263 recovery records representing 10 management units in eastern Colorado and 2 management units in Western Colorado are available to evaluate the possibility of distinct winter populations which potentially could be managed individually. Estimated survival and recovery rates and recovery distributions will be the criterion used to distinguish populations. I present in this initial report preliminary sorting and tabulation of data in preparation for various tests of age, sex, geographic, and temporal specificity of survival and recovery rates, and recovery distributions. ��153 ANALYSIS OF MALLARD WINTER BANDING DATA COLLECTED IN COLORADO Mark A. Wotawa P. N. OBJECTIVES 1. Estimate population parameters of mallards wintering in (1) the eastern or Central Flyway portion of Colorado, and (2) the western or Pacific Flyway portion of Colorado by age and sex class, and by management unit where possible. Specific parameters include: recovery rates, survival rates, mean life span, and geographic distribution of harvest. 2. Prepare a final report upon which to base management recommendations. SEGMENT OBJECTIVES 1. Obtain banding and recovery tapes from the u.S. Fish and Wildlife Service Bird Banding Laboratory for: a. Normal, wild mallards banded postseason in eastern Colorado during the period 1963-64 through'1986-87 and recovered during the 1964-65 through 1989-90 hunting seasons. b. Normal, wild mallards banded postseason in western Colorado during the period 1973-74 through 1982-83 and recovered during the 1974-75 through 1989-90 hunting seasons. 2. In all analyses use only recoveries resulting from the above bandings, recovered anywhere, and only those shot and/or found dead during the period September 1 through January 31. 3. Employ standard computer programs to produce desired printouts of number banded, recovery tables, and geographic distribution of recoveries by age and sex class and by banding location. 4. Estimate recovery rates, survival rates, and mean life spans from computer programs using two analysis methods developed by (1) Brownie and Robson (1974), and (2) Seber (1970), and Robson and Youngs (1971). Use other analysis methods when appropriate. 5. Analyze recovery data by banding location to compare population parameters among locations and to identify any distinct population sub-units. 6. All birds were aged (adult vs. subadu1t) during all years of banding in both eastern and western Colorado. However, the accuracy of such aging is questionable because of changes in personnel beginning with the 1976-77' banding period in eastern Colorado and with the 1981-82 banding period in western Colorado. Analyze data in each area separately for the two periods to check for differences before pooling. 7. Prepare progress report. �154 BACKGROUND A new era in managing waterfowl through harvest regulations began in 1952 with the acceptance of 4 flyways as the principle management units within the United States. Although these flyways were considered administrative units, they were generally based upon different major migrational pathways of birds, especially anatids, across the U.S. This was the first major step to manage waterfowl at a population level. Subsequent divisions and refinements of flyways were imminent as states became involved in the regulation process via flyway councils and the knowledge to better define unique waterfowl populations increased. Indeed, in 1961 a special mallard management unit was established at the Columbia Basin of the Pacific Flyway, and a second, the High Plains Mallard Management Unit (HPMMU) , was established in 1972 for the western portion of the Central Flyway. In the winter of 1963-64, Colorado independently began a long term winterbanding effort to study the possibility of managing their eastern Colorado mallard population on a flock basis. The resulting data set may well be the largest for any state in the country for mallards. Winter-banding of mallards east of the Continental Divide continued uninterrupted through the winter of 1984-85, except at Bonny Reservoir where banding continued through 1986-87. Efforts targeted 1,000 bandings, 250 of each age and sex class, for each of 7 management units. A similar effort was initiated in western Colorado in the winter of 1973-74 and ended in 1982-83. Approximately 114,000 and 14,000 mallards were banded in eastern and western Colorado respectively, of which approximately 10,000 of the eastern Colorado bandings and 1,400 of the western Colorado bandings were recovered during subsequent hunting seasons. The High Plains Mallard Management Unit (HPMMU) was proposed after analysis of banding data prior to 19~6 indicated differences in population and harvest parameters for the western and eastern Central Flyway (Grieb et al. 1966; Grieb and Funk 1966). In addition, the Central Flyway states initiated a cooperative mid-winter banding study in 1965-66 to gain further knowledge of major mallard wintering areas. The results of this study provided justification for such a unit (Funk et al. 1971), and in 1972 the HPMMU was established as that portion of the Central Flyway lying to the west of the 1000 W. longitude. Differences in distribution of harvest, recovery and survival rates, and hunting pressure were the main factors supporting 2 management units. Along with the split came differential hunting regulations favoring the HPMMU, specifically, those targeting drake mallards (Funk et a1. 1968; Grieb et al. 1970). More importantly, the creation of the HPMMU further established the trend of waterfowl managers to base regulations on biologically distinct populations. Preliminary analyses of the Colorado banding data are presented in previous federal aid game research reports but are limited to only partial summaries. Additionally, Hopper et al. (1978) examined age-specificity for mallards banded in eastern Colorado through the 1976-77 hunting season. They found no difference in recovery and survival rates between sub-adults and adults for either sex. However, they did find that sub-adults of both sexes tended to wander more than adults during the first year after banding. They did not examine sex specific differences by banding area. Nichols and Hines (1987) included Colorado bandings while analyzing winter-bandings nationwide. They also found no difference between survival rates by age. However, when Colorado was broken down into 4 �155 geographic regions, they found sex-specific differences in survival and recovery rates, and recovery distributions within some regions were age specific. The last analysis of data from western Colorado was conducted in 1980 for recoveries through the 1979-80 hunting season (Hopper 1981). Western Colorado is located in the Pacific Flyway and mallards were exposed to a generally more liberal set of regulations characteristic of that flyway. Several major events important to management of mallards have occurred since the onset of Colorado's banding studies. Foremost is the drought condition the prairie-pothole region has experienced in the 80's and the subsequent decline of the continental mallard population (Johnson and Shaffer 1987). The vast majority of Central Flyway and thus Colorado's wintering mallards are produced in this region (Anderson and Henny 1972). Because of declining duck numbers and the poor breeding ground conditions, the U.S. Fish and Wildlife Service has called for a reevaluation of the HPMMU to determine if it should continue in its present form. Analyses of Colorado's banding data will contribute strongly to this reevaluation. The views of how harvest affects overall mortality of mallard populations (additive vs. compensatory) are largely contradictory (Nichols et al. 1984), but have leaned toward the compensatory hypotheses in recent years (Anderson and Burnham 1976; Nichols et al. 1984). Inherent within the compensatory hypotheses is a threshold harvest level above which harvest is no longer compensatory, but becomes additive (Anderson and Burnham 1976). Continent wide, mallard harvest is probably below this threshold, but on a local basis this may not be necessarily true. The implications of the above is that proper management may rely heavily upon the ability to more closely identify individual populations and regulate harvest below the threshold levels via carefully selected sex-specific regulations. The development of proper methods to analyze banding data has increased rapidly during the past 20 years. A summary of these methods which derive parameter estimates and their standard errors, and tests among strata (e.g. sex, age and years) are given by Brownie et al. (1985). Several studies to evaluate the failure of assumptions associated with the models of Brownie et al. (1985) have also been conducted in recent years. Anderson and Burnham (1980) examined the effect of delayed reporting of bands and Nelson et al. (1980) examined the effect of band loss on survival estimates. The assumption of homogeneous individual survival probabilities was considered by Pollock and Raveling (1982), Nichols et al. (1982), and Rexstad (1990). Extensions of banding analysis methods include the simultaneous use of live recapture data (Anderson pers. comm.) and stratification after bands are recovered (Schwarz 1988; Schwarz et al. 1988). This proj ect is the culmination of the banding effort in Colorado since the winter of 1963-64. This report presents the initial efforts of data acquisition and tabulation by banding area, age, sex, and time. I also present summaries of distribution of recoveries within North America and Colorado. METHODS Data acquisition All records were obtained from the BBL and included only normal wild �156 mallards (code 3-00) banded in Colorado during Dec. - Mar., 1963-64 through 198687, and recoveries from these bandings which were shot (code 01) or found dead (code 00) during the hunting season (Sep. - Jan.) through 1989-90. Changes in age codes were implemented by the BBL in July, 1967 resulting in the following age classifications for this analysis: Birds banded prior to 1968 with code 1 are adults and code 2 or 5 are subadults. Birds banded in 1968 and later, during December and coded 1, 5, or 6 are adults and coded 2 are subadults. Birds banded in 1968 and later during Jan. -Mar. and coded 6 are adults and coded 2 are subadults. These files were reduced to include bandings from 20 Dec. -29 Feb. to minimize the time interval over which banding occurred (Brownie et a1. 1985). Consequently, estimation of annual survival rates will refer to the approximate period of 24 January to 23 January the following year. The few bandings which occurred outside the main study areas and any recoveries obtained the same winter as they were banded were dropped from the analysis. Unit and Region Designations One objective of this analysis was to identify biologically distinct wintering populations of mallards based on available banding data. Banding data are coded by 10' latitude/longitude blocks at the BBL, but in most cases, banding did not occur sufficiently or consistently within 10' blocks to conduct meaningful analyses. Consequently, adjacent 10' blocks will initially be grouped into larger areas for analysis representing Colorado's original management units. I had to make a compromise when grouping individual 10' blocks of data between a-priori knowledge of primary mallard winter/harvest concentrations and availability and location of data. My objective was to group the data into the smallest areas possible and still maintain sufficient data to produce meaningful results. When banding began in 1963, Colorado was divided into 16 "waterfowl management units" representing major winter/harvest concentrations (see ego Grieb and Funk 1966). Szymczak (1986) used similar "harvest units" in his analysis of waterfowl banded in Colorado's mountain parks, but divided western Colorado into 5 units and grouped the 6 units of southeast Colorado. I adopted unit boundaries and their respective names from Szymczak (1986) for this analysis. The 20 unit boundaries (Fig. 1) differ slightly from the original and Szymczak's to facilitate grouping of adequate data in each unit. In many cases, preliminary testing suggested data were insufficient at the unit level. For these cases, after appropriate tests to justify pooling, some adjacent units may be combined into what I define as regions (Fig. 1). Banding and recoveries for units of southeast Colorado were especially scarce (see appendix A). Although data are summarized separately for units in the southeast, parameter estimates and hypotheses testing will most likely require these units to be pooled into 1 region. In a few instances pooling of regions may be required; this is especially true for female mallards, particularly at Bonny Reservoir and Southeast Colorado where recovery rates were low. Mallards populations in eastern and western Colorado are recognized as completely different populations. Consequently, these 2 areas were kept separate during all phases of the analysis. Recovery Distribution Distribution of recoveries are presented (as a percent) for each banding �I Ll ~~~~~;~ I soun- PLAJ"TE R. I ~ Yampa \ River' \ \ FOOTHILLS 41 Sterling- Ft. Mor~a~~' \ Julesburg Greeley-" ...., Sterling Ft. Morgan \ Southern Foothills Colorado River ESTERN COLORADO ······················r······r·································l li L.···· . BONNY RESERVOIR MOUNTAIN PARKS Gunnison River Unit 10 Unit 13 ....J Unit 12 San Luis Valley Southwest f..· ' ····································l : 38 l····· ····················r····· Unit 11 Unit 14 ----, 109 108 Figure 1. 107 Unit and region 106 designations 39 SOUTHEAST South Park !.........- ~------------T\ Unit 8 ................................................................ , \ ~ ' 40 105 used in analyses of Colorado's winter banded 37 102 103 104 r mallards. I-' V1 -....J �158 region by age, sex, and year after banding (direct and indirect recoveries). Appendix B tables recoveries by state and flyway, while appendix C tables Colorado recoveries by unit and region. One should be aware when examining the recovery distribution tables in this report that true movement patterns are confounded with variable harvest and band reporting rates among age, sex, geographic and temporal classes. Variable bag limits, season timing and lengths, hunter preference, susceptibility to hunters, and band reporting rates across the continent and among years result in recovery distributions which reflect harvest and band reporting rates rather than true movement patterns. The tables presented in this report are only the first steps in analyzing movement patterns and are presented only as data summaries. RESULTS AND DISCUSSION Data Samples Banding occurred in 51 10' latitude/longitude blocks representing 10 management units in eastern Colorado and 2 management units in western Colorado. A total of 128,211 banded mallards and 11,263 recoveries were used in this analysis (table 1). Adult and subadult males were the most frequently banded in each region, comprising 31 and 26 percent of the total respectively, while adult and subadult females comprised 20 and 22 percent. The number of bandings varied annually, but age-sex ratios within years were fairly consistent. Percent recovered was highest for males which were 2-3 times that of females. Subadults tended to have a slightly higher percentage recovered than adults in both sex classes. Bonny Reservoir and the units of southeast Colorado tended to have a lower percent recovered especially for female mallards. Recovery Distribution Recovery distributions of subadults tended to be more scattered than adults; adults banded in eastern Colorado regions had a greater percentage recovered (from 7.5 - 37.5) in the High Plains Unit (tables 12-13). Greater differences occurred for direct recoveries and for those banded at Bonny Reservoir and Southeast Colorado. The difference was generally divided among the Low Plains Unit, Canada, and the Pacific and Mississippi Flyways. The higher proportion of subadults recovered in Canada may reflect differences in nesting chronology and timing of migration, although no obvious latitudinal patterns emerged between adults and subadults within the High Plains Unit. The greater proportions recovered elsewhere most likely reflect a true difference in movement patterns. The apparently low proportion of recoveries for mallards banded at Bonny Reservoir and Southeast Colorado (tables 2-3) may be misleading. These regions exhibited the lowest recoverY rates in Colorado which are lower than that of the Low Plains portion of the Central Flyway and the Mississippi Flyway. Thus the low recovery proportions in these areas may reflect differences in harvest patterns rather than true differences in movement. The distribution of Colorado recoveries (tables 4-5) indicate high fidelity to the winter location of banding. The South Platte and Foothills had the most exchange between any 2 regions. There were few recoveries south of their respective banding location for those recovered in Colorado indicating little �159 tendency for mallards to migrate further than where they spent their first winter. F1JTURERESEARCH During the next segment, analyses will include evaluation and parameter estimates of age, sex, geographic, and temporal variation of survival and recovery rates. Additionally, more objective methods to evaluate differential recovery distributions by age, sex, banding area, banding year, and year after banding will be implemented. LITERATURE CITED Anderson, D. R. and C. J. Henny. 1972. Population ecology of the mallard: I. A review of previous studies and the distribution and migration from breeding areas. Resour. Publ. 105. 94 pp. Anderson, D. R. and K. P. Burnham. 1976. Population ecology of the mallard: VI. The effect of exploitation on survival. Resour. Publ. 128. U.S. Fish and Wildl. Servo 66 pp. Anderson, D. R. and K. P. Burnham. 1980. Effect of delayed reporting of band recoveries on survival estimates. J. Field Ornithol. 51:244-247. Brownie, C., D. R. Anderson, K. P. Burnham, and D. S. Robson. 1985. Statistical inference from band recovery data: a handbook. 2nd ed. U.S. Fish Wildl. Servo Resour. Publ. 156. 216 pp. Brownie, C. and D. S. Robson. 1974. Models allowing for age-dependent survival rates for band-return data. Cornell Univ. Biometrics Unit. (mimeo). Funk, H. D., J. R. Grieb, G. F. Wrakestraw, and D. Witt. 1968. A proposed mallard. drake season in Central Flyway Montana, Wyoming, and Colorado. Central Flyway Technical Committee Report. 12 pp. Funk, H. D., J. R. Grieb, D. Witt, G. F. Wrakestraw, G. W. Merrill, T. Kuck, D. Timm, T. Logan, and C. D. Stutzenbaker. 1971. Justification of the Central Flyway High Plains Mallard Management Uni t. Central Flyway Technical Committee Report. 48 pp. Grieb, J. R. and H. D. Funk. 1966. Analysis of mallard recoveries from birds banded in eastern Colorado prior to 1962. Colo. Div. Wildl. Game Res. Rept., Oct., 109-126. Grieb, J. R., H. Funk, D. Witt, G. Wrakestraw, andL. Serdiuk. 1966. Aproposed Mallard Management Unit for the Central Flyway. Central Flyway Technical Committee Report. 32 pp. Grieb, J. R., H. D. Funk, R. M. Hopper, G. W. Wrakestraw, and D. Witt. 1970. Evaluation of the 1968-69 experimental mallard drake season in Montana, Wyoming and Colorado. 22 pp. �160 Hopper, R. M., H. D. Funk, and D. R. Anderson. 1978. Age specificity in mallards banded postseason in eastern Colorado. J. Wildl. Manage.42:263270. Hopper, R. M. 1981 Population characteristics of mallards wintering in westcentral Colorado. Colo. Div. of Wildl. Wildl. Res. Rept., Oct. p.37-50. Johnson J. H. and T. L. Shaffer. 1987. Are mallards declining in North America. Wildl. Soc. Bull. 15:340-345. Nelson, L. J., D. R. Anderson, and K. P. Burnham. 1980. The effect of band loss on estimates of annual survival. J. Field Ornitho1. 51:30-38. Nichols, J. D. and J. E. Hines. 1987. Population ecology of the mallard VIII: Winter distribution patterns and survival rates of winter-banded mallards. u.S. Fish Wildl., Resour. Publ. 162. 154 pp. Nichols, J. D., S. L. Stokes, J. E. Hines, and M. J. Conroy. 1982. Additional comments on the assumptions of homogeneous survival rates in modern bird banding estimation models. J. Wildl. Manage. 46:953-962. Nichols, J. D., M. J. Conroy, D. R. Anderson, and K. P. Burnham. 1984. Compensatory mortality in waterfowl populations: a review of the evidence and implications for research and management. Trans. N. Amer. Wildl. and Natur. Reour. Conf. 49:535-554. Pollock, K. H. and D. G. Raveling. 1982. Assumptions of modern band-recovery models, with emphasis on heterogeneous survival rates. J. Wildl. Manage. 46:88-98. Rexstad, E. A. 1990. Models of exploitation and heterogeneity in survival probabilities of banded waterfowl populations. PhD Thesis, Colorado St. Uni., Ft. Collins, CO. Robson, D. S., and W. D. Youngs. 1971. Statistical analysis of reported tagrecapture in the harvest from an exploited population. Cornell Univ. Biometrics Unit Mimeo. Series, Paper No. BU-369-M. Schwarz, C. J. 1988. Post Release Stratification and migration models in bandrecovery and capture-recapture models. PhD. Dissertation. U. Manitoba, Winnipeg, Manitoba, Canada. 384 pp. 1988 Post-release Schwarz, C. J., K. P. Burnham, and A. N. Arnason. stratification in band-recovery models. Biometrics. 44:765-785. Seber, G. A. F. 1970. Estimating time-specific survival and reporting rates for adult birds from band returns. Biometricka. 57(2):313-318. Szymczak, M. R. 1986. Characteristics of duck populations in the intermountain parks of Colorado. CO Div. Wildl. Tech. Publ. 35. 88 pp. Prepared by: ~C)~celJajL-0t.-~ Howard D. Funk Wildlife Program Specialist �161 Table A-1. Colorado. Recovery matrix for male mallards banded dur i ng winter within the Sterling-Julesburg management unit, Adults Year Recovered Nunber Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 19n 1978 1979 1980 1981 1982 1983 60 288 249 286 192 97 0 161 183 240 251 308 234 151 158 126 119 124 125 125 143 65 0 66 67 68 69 70 71 72 73 74 75 76 rr 78 79 80 81 82 83 84 85 86 87 88 89 0 6 5 0 8 8 14 0 9 7 5 5 0 4 5 5 8 3 2 1 0 7 6 3 0 0 4 1 3 2 3 0 11 0 0 2 6 4 7 0 11 13 0 0 2 2 1 0 0 2 9 15 0 0 0 1 1 0 0 1 1 4 6 0 0 1 1 1 0 0 2 4 5 11 16 0 0 0 0 0 1 0 2 1 7 3 7 8 0 0 0 0 1 0 0 3 0 1 4 4 2 3 0 0 1 0 0 0 0 0 1 5 2 2 6 3 5 0 0 0 0 0 0 0 0 0 1 5 1 3 1 4 5 0 0 0 0 0 0 0 0 2 0 2 2 3 0 3 1 1 0 0 0 0 0 0 0 0 0 0 0 3 4 0 3 2 2 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 3 1 2 0 0 0 0 0 0 0 0 0 0 1 0 3 0 1 1 3 2 5 4 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 2 0 3 3 1 7 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 2 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 Subadults Year Recovered Nunber Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 19n 1978 1979 1980 1981 1982 1983 81 82 274 328 201 114 0 143 175 207 257 299 222 210 162 127 121 125 124 125 146 5 65 66 67 68 69 70 71 72 1 3 1 0 8 1 2 5 8 2 2 7 6 14 3 2 4 9 2 3 0 0 4 7 3 8 0 1 1 2 6 0 1 0 3 1 0 3 3 2 1 0 6 11 74 75 76 rr 78 79 80 81 82 83 84 85 86 87 88 89 0 0 0 0 . 1 3 2 2 3 1 1 0 0 0 4 0 9 2 7 4 5 0 0 0 0 0 1 0 2 6 5 12 11 0 0 1 0 0 0 0 1 1 1 3 10 3 0 0 1 2 0 0 0 0 1 0 4 8 4 7 0 0 0 0 0 0 0 4 0 3 3 2 5 3 7 0 0 0 0 0 0 0 0 1 2 5 1 5 4 0 3 0 0 0 0 0 0 0 0 0 0 1 2 2 3 0 2 4 0 0 0 0 0 0 0 0 0 3 0 1 3 3 4 5 1 5 0 0 0 0 0 0 0 0 0 0 1 4 1 0 0 2 4 6 4 0 0 0 0 0 0 0 0 0 0 1 0 1 0 2 2 5 5 2 8 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 1 0 1 4 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 2 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 2 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 73 1 1 1 �162 Table A-2_ Colorado. Recovery matrix for male mallards banded during winter within the Ft. Morgan-Sterling management unit, Adults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 365 777 329 437 407 207 141 303 266 247 206 247 250 150 229 125 125 128 125126 137 128 8 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 7 12 8 12 6 7 16 7 13 4 15 3 5 19 3 13 3 8 11 10 5 6 6 13 20 14 3 5 3 3 6 7 7 5 14 0 6 1 6 10 1 8 17 14 0 1 0 1 3 3 2 9 14 8 0 0 0 0 0 0 1 3 3 3 1 0 0 0 1 3 0 1 2 5 4 7 6 0 0 0 0 0 0 1 1 1 3 4 7 8 0 0 0 0 0 0 0 2 0 3 1 4 5 4 0 0 0 0 0 0 0 0 0 1 3 5 11 3 5 0 0 1 0 1 0 0 0 0 2 1 0 0 6 4 4 0 0 0 0 0 0 0 1 1 1 0 1 1 1 6 2 1 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1 2 2 3 0 0 0 0 0 0 0 0 0 0 1 0 2 1 2 2 3 7 4 0 0 0 0 0 0 0 0 0 0 0 0 1 3 2 2 1 1 3 9 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 2 2 3 2 2 3 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 1 0 1 6 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 2 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 Subadults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 227 209 410 283 314 238 148 318 272 295 205 289 242 196 147 117 166 129 127 127 132 74 7 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 5 4 5 1 7 2 5 11 10 5 1 10 7 17 2 2 11 3 10 16 1 3 5 8 8 7 6 2 1 7 3 4 9 3 10 1 2 4 0 8 6 3 17 14 1 3 3 3 0 2 2 9 10 9 0 0 2 1 0 1 0 2 6 8 7 0 0 0 0 1 1 0 4 5 10 6 10 0 0 0 0 2 0 1 1 2 4 7 5 7 0 0 1 1 1 2 2 0 1 3 4 5 9 8 0 0 0 0 0 1 1 1 2 1 2 1 4 7 3 0 0 0 0 0 1 0 0 1 1 4 4 7 0 4 2 0 0 0 0 0 0 0 0 1 1 1 3 2 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 1 2 0 2 2 7 7 0 0 0 0 0 0 0 0 0 1 0 1 0 2 1 0 1 3 5 0 0 0 0 0 0 0 0 0 3 0 1 1 0 1 1 4 3 6 7 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 3 2 1 1 0 0 0 0 0 0 0 0 0 0 1 0 1 1 0 0 3 1 1 3 5 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 4 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 �163 Table A-3. Colorado. Recovery matrix for male mallards banded during winter within the Greele~-Ft. Morgan management unit, Adults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 99 410 287 250 252 162 150 198 204 241 197 248 354 103 302 139 125 125 146 125 134 5 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 1 12 0 10 7 1 9 10 14 0 6 6 8 11 0 5 8 2 7 4 2 5 3 4 10 6 5 0 2 4 5 5 1 7 12 0 5 1 1 3 4 2 5 10 0 2 1 1 1 4 0 4 5 14 0 1 0 0 0 1 2 3 3 6 2 0 0 0 0 2 0 0 1 1 2 4 11 0 0 0 1 0 0 0 1 3 2 2 3 11 0 0 0 0 1 2 0 2 2 4 4 3 13 3 0 0 0 0 0 1 0 0 1 0 6 1 5 6 7 0 0 0 0 0 0 0 1 0 0 0 2 4 1 4 2 0 0 0 0 0 0 0 1 0 0 1 1 1 0 4 3 1 0 0 0 0 0 0 0 0 0 1 0 0 4 0 4 2 3 7 0 0 0 0 0 0 1 0 0 0 0 0 3 0 3 4 1 1 4 0 0 0 0 0 0 0 0 0 0 1 0 1 1 3 2 1 7 7 7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 3 1 2 1 2 2 0 0 0 0 0 0 0 0 0 0 0 0 1 0 2 1 0 1 2 0 4 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 2 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 Subadults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 67 320 322 320 252 152 159 199 209 226 209 289 289 102 79 129 132 129 149 129 132 4 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 2 5 0 8 9 0 4 5 9 0 4 6 10 10 0 3 9 11 5 4 2 6 4 7 8 9 4 1 4 3 3 2 4 3 11 0 4 4 3 4 5 8 7 9 0 0 2 4 1 1 3 5 5 7 0 0 0 2 1 0 1 3 1 8 3 0 1 1 1 1 1 0 4 2 1 4 5 0 0 0 0 2 0 2 2 4 3 3 8 7 0 1 0 0 0 0 1 1 1 0 2 6 3 4 0 0 0 0 0 0 1 1 1 2 0 7 9 6 4 0 0 0 1 0 0 0 0 3 2 0 2 6 2 0 6 0 0 0 0 0 0 0 0 1 1 2 0 0 1 4 0 6 0 0 0 0 0 0 0 1 0 0 0 0 4 1 1 2 3 6 0 0 0 0 0 0 0 0 1 1 2 0 1 0 0 2 5 2 3 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 1 3 5 2 5 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 1 1 2 3 4 4 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 1 0 0 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 3 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 �164 Table A-4. Colorado. Recovery matrix for male mallards banded during winter within the Northern Foothills management unit, Adults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 493 472 284 290 252 150 150 160 197 201 153 245 176 213 196 185 78 127 124 129 143 160 7 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 10 12 5 10 5 7 12 12 12 12 8 8 10 5 3 4 2 7 9 5 3 6 4 4 7 7 6 2 3 2 1 9 2 2 10 1 1 1 6 2 3 5 6 12 0 1 1 3 0 0 6 3 5 7 1 0 1 2 0 0 0 2 2 2 4 0 1 0 0 2 1 1 3 3 4 6 6 0 0 0 0 0 1 1 0 0 1 3 7 0 0 0 0 0 0 0 0 0 1 2 3 6 7 6 0 0 0 0 0 0 0 0 1 1 5 9 10 9 7 0 0 1 1 0 1 0 0 0 1 0 2 4 6 5 10 0 0 0 0 0 0 0 0 1 0 0 1 0 4 3 1 3 0 0 0 0 0 0 0 0 0 0 1 2 3 3 1 4 2 8 0 0 0 0 0 0 0 0 0 0 0 1 0 0 2 1 1 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 3 1 2 6 3 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 1 2 3 4 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 1 1 2 1 3 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 1 1 1 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 Subadults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 333 238 299 289 245 160 152 152 226 89 158 178 149 135 214 75 76 119 135 137 130 52 9 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 10 6 11 2 11 2 4 6 13 2 7 7 5 5 5 2 5 9 7 5 2 1 9 4 12 5 5 1 2 4 5 2 5 8 7 1 1 4 1 4 8 3 3 12 0 0 1 2 5 4 3 5 9 6 1 0 0 1 0 0 0 1 2 2 3 0 0 0 0 0 1 0 0 4 0 3 9 0 0 1 0 0 0 1 1 5 1 1 3 0 0 0 0 0 1 0 2 2 1 2 2 0 1 0 1 0 0 0 0 0 0 0 2 0 0 0 0 0 0 1 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 0 0 0 2 0 2 2 2 2 3 2 0 0 0 0 0 0 0 0 0 0 0 2 2 0 0 0 0 0 1 0 2 1 1 5 1 0 1 6 1 2 1 0 1 1 1 5 7 8 1 0 2 0 1 1 6 6 0 0 2 0 1 1 2 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 3 3 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 3 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 0 0 6 1 1 2 3 1 2 5 2 2 1 4 7 0 2 9 �165 Table A-5. Colorado. Recovery matrix for male mallards banded dur i ng winter within the Southern Foothills management unit, Adults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 547 593 479 249 295 149 29 151 222 316 200 249 419 232 291 216 174 132 128 172 129 242 13 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 14 9 14 19 17 9 16 19 9 4 10 10 8 16 6 8 10 2 7 9 4 2 9 7 10 6 1 2 4 2 6 4 3 1 6 2 3 4 3 7 4 0 9 17 0 1 1 1 2 1 0 2 1 23 0 1 0 0 1 0 1 1 2 3 9 0 0 0 0 1 0 0 2 3 7 13 11 0 0 0 0 1 0 0 0 3 4 7 9 13 0 0 0 0 0 0 0 0 1 2 1 0 12 6 0 0 0 0 0 1 0 0 0 1 0 7 14 13 9 0 0 0 0 0 0 0 0 1 2 2 1 9 1 7 10 0 0 0 0 0 0 0 1 0 1 0 2 1 1 3 2 7 0 0 0 0 0 0 0 0 0 1 0 2 6 2 5 3 4 4 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 6 14 0 0 1 3 1 1 0 4 0 0 1 0 2 5 4 0 0 1 0 0 1 1 4 0 1 4 85 86 87 88 89 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 a 1 3 3 4 4 a 3 a 4 3 4 10 a a 1 a 2 4 4 10 a a a a a a a a a a a a 0 a a Subadul ts Year Recovered Number Year Banded 64 1963 1964 1065 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 196 240 300 265 305 130 25 205 232 311 228 266 418 231 256 236 173 149 127 136 126 108 9 65 66 67 68 4 6 5 1 12 3 12 4 17 4 5 5 7 14 69 70 71 72 73 74 75 76 77 78 2 1 6 6 11 16 5 3 0 2 3 5 4 3 1 9 0 2 2 4 7 5 0 3 13 1 1 1 2 1 5 2 6 6 15 0 0 0 0 0 0 0 2 8 6 7 0 0 1 0 0 a 0 a 0 0 0 0 0 0 1 0 0 a 7 2 10 2 a a 1 7 5 9 10 2 0 a 1 4 6 4 9 15 a 0 0 a a 2 1 3 1 5 11 10 a 0 1 5 2 3 12 9 10 79 80 81 82 83 84 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 0 6 5 1 2 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 a 0 0 0 0 a 0 1 a 4 3 4 3 11 6 a 0 0 0 0 0 0 3 2 4 5 2 a 0 1 0 2 5 1 4 12 a 0 a 0 0 1 2 2 5 5 5 2 6 11 a 1 0 a 0 1 0 0 1 1 1 3 9 a a a a a a 0 a a a a 0 1 a 3 1 1 1 5 1 3 a a 0 a 0 a a 1 0 1 a a a 1 a 0 1 3 3 a a a a a a a a a a a a 1 0 0 a a a a a a a 0 a 1 1 1 2 1 0 0 0 0 0 a a 0 a a a a 0 0 0 a a a a 0 a 0 a 1 1 �166 Table A-6. Recovery matrix for male mallards banded during winter within the Bonn~ Reservoir management unit, Colorado. Adults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 86 595 331 258 248 151 153 196 256 202 263 259 250 528 716 401 363 250 519 151 133 248 154 83 2 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 1 8 1 13 8 1 7 6 2 2 3 5 12 3 0 2 6 3 6 5 1 5 3 4 7 1 2 0 2 3 4 1 2 1 2 0 3 2 1 4 1 9 4 10 0 3 1 1 1 2 0 4 3 4 0 1 0 2 1 0 1 2 3 6 11 0 0 0 2 0 0 1 2 2 2 7 11 0 0 0 0 0 1 1 2 5 2 5 5 7 0 0 0 1 1 0 1 1 2 1 2 5 9 12 0 0 0 0 0 0 1 0 3 2 2 3 1 19 12 0 0 0 0 0 0 0 0 0 0 2 2 3 4 17 10 0 0 0 0 0 0 0 1 0 0 3 1 0 1 7 5 2 0 0 0 0 0 0 0 0 0 1 0 1 3 11 7 11 6 3 0 0 0 0 0 0 0 0 0 1 0 2 0 3 10 4 4 9 22 0 0 0 0 0 0 0 0 0 0 1 0 0 4 4 5 4 10 15 4 0 0 0 0 0 1 0 0 0 0 0 0 1 2 1 0 3 t 8 3 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 3 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 3 1 1 1 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 1 1 8 1 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 Subadults Year Recovered Number Year Banded 64 65 66 67 68 69 70 71 5 0 1 1 2 9 3 1 6 7 2 1 5 6 8 1 2 1 7 9 6 0 1 6 2 7 4 4 0 0 4 5 2 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 98 148 288 277 267 173 150 210 246 152 224 250 250 498 380 399 306 272 150 150 124 59 177 75 2 0 9 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 0 1 0 2 1 2 2 2 3 4 7 0 1 0 0 0 1 0 1 1 1 6 0 0 3 1 0 0 1 0 2 0 7 10 0 0 0 0 0 1 2 1 0 1 4 2 9 0 0 1 1 0 0 1 1 0 3 2 3 7 12 0 0 0 0 1 0 0 1 2 1 3 3 4 7 9 0 0 0 0 0 0 2 0 1 1 3 0 2 5 8 12 0 0 0 1 0 0 0 0 1 0 2 0 2 4 7 6 11 0 0 0 0 0 0 0 1 0 0 1 0 2 5 3 5 6 4 0 0 0 0 0 0 0 1 1 0 0 2 0 4 2 8 0 5 4 0 0 0 0 0 0 0 0 1 0 0 0 0 0 3 5 2 7 4 7 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 2 3 5 1 4 3 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 2 0 1 0 0 0 4 2 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 6 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 2 1 1 2 1 0 0 1 0 2 4 3 3 2 3 6 7 1 0 0 0 0 2 1 1 1 0 6 0 1 �167 Table A-7. Recovery matrix for male mallards banded during winter within management unit 10, Colorado. Adults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 19n 1973 1974 1975 1976 19n 1978 1979 1980 1981 1982 1983 135 0 138 0 0 125 0 0 0 53 0 0 0 0 0 0 0 0 0 3 32 2 65 66 67 68 69 70 71 72 73 74 75 76 rr 78 79 80 81 82 83 84 85 86 87 88 89 1 0 2 0 0 1 0 2 0 2 0 3 0 0 0 0 3 0 0 3 1 0 4 0 0 3 0 1 0 0 0 0 5 0 0 1 0 5 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 2 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Subadu[ts Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 19n 1973 1974 1975 1976 19n 1978 1979 1980 1981 1982 1983 76 0 169 0 38 161 0 0 0 46 0 0 0 0 0 0 0 0 0 2 33 3 65 66 67 68 69 70 71 72 73 74 75 76 rr 78 79 80 81 82 83 84 85 86 87 88 89 0 0 0 0 3 0 0 2 0 1 0 4 0 1 0 0 3 0 0 3 0 0 0 0 0 6 0 0 0 2 0 0 4 0 0 0 0 0 0 1 5 0 0 0 0 0 1 0 0 2 0 0 0 2 0 0 0 0 0 1 0 0 0 3 0 0 0 2 0 0 1 0 0 0 2 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 �168 Table A-8. Recovery matrix for male mallards banded during winter within management Unit 11, Colorado. Adults Year Recovered NUilber Year Banded 67 1966 1967 1968 1969 1970 1971 19n 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 0 0 0 77 11 100 87 154 119 217 241 38 250 194 271 0 0 0 0 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 2 0 0 0 3 0 3 4 0 0 0 1 0 0 0 0 0 0 1 2 2 0 0 0 0 0 1 1 6 1 3 0 0 0 0 0 2 0 1 2 2 6 0 0 0 0 0 0 1 0 1 1 6 2 0 0 0 0 0 0 0 2 1 2 2 0 6 0 0 0 0 0 0 0 1 1 1 3 0 6 3 0 0 0 0 0 0 0 1 1 0 4 0 1 3 7 0 0 0 0 0 0 0 0 0 0 0 1 2 2 .6 0 0 0 0 0 0 0 1 0 0 0 1 0 7 4 4 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O. 0 0 0 Subadults Year Recovered Number Year Banded 67 1966 1967 1968 1969 1970 1971 19n 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 8 0 0 60 15 68 24 47 171 84 200 23 175 113 28 0 0 1 0 68 69 70 71 rz 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 1 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 1 1 2 0 0 0 0 0 1 0 0 1 2 0 0 0 1 0 0 0 1 3 0 4 0 0 0 0 0 0 0 0 2 0 3 1 0 0 0 0 0 1 1 0 0 1 3 0 4 0 0 0 0 0 0 0 2 0 1 0 0 3 3 0 0 0 0 0 1 0 0 0 0 3 0 2 1 0 0 0 0 0 1 0 0 0 0 0 0 0 1 4 0 0 0 0 0 0 0 0 0 0 0 0 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 �169 Table A-9_ Recovery matrix for male mallards banded during winter within management unit 12, Colorado. Adults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 380 0 196 . 160 143 25 75 246 216 192 20 49 150 12 249 11 73 0 0 0 217 8 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 7 0 5 0 6 4 0 6 5 2 0 2 4 0 2 0 7 3 5 0 2 0 4 0 1 1 3 2 0 2 1 1 3 0 15 1 0 1 0 3 0 2 4 7 0 0 1 1 1 0 1 2 3 3 0 0 0 1 1 0 1 2 2 4 2 0 0 0 0 0 0 0 4 2 3 1 1 0 0 0 0 0 0 0 0 0 1 0 1 3 0 0 0 0 0 0 1 1 0 2 1 0 3 1 0 0 0 0 0 0 0 0 2 3 0 0 0 1 7 0 0 0 0 0 0 0 0 0 1 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 2 0 0 0 0 0 0 0 1 0 0 0 0 2 0 3 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Subadul ts Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 19n 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 157 0 102 152 147 30 77 186 40 154 8 17 150 7 185 4 26 0 0 0 217 3 65 66 67 68 69 70 71 2 0 3 0 0 1 0 2 4 1 0 0 3 3 1 0 2 1 6 0 1 0 0 2 1 0 3 0 0 1 1 6 2 2 4 rz 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 1 0 5 0 6 0 1 7 2 0 0 0 2 0 0 2 2 1 7 0 0 1 0 1 0 0 0 0 5 0 0 0 0 0 2 0 0 2 0 2 0 0 0 0 0 0 0 0 1 0 0 2 1 0 0 0 0 0 0 1 0 1 0 2 0 0 3 0 0 0 0 0 2 0 0 0 0 2 0 0 2 0 7 0 0 0 0 0 0 0 1 0 0 0 1 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 2 0 1 0 0 1 0 1 0 1 0 0 0 0 0 2 0 2 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 1 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 4 �170 Table A-10. Recovery matrix for male mallards banded during winter within management unit 13, Colorado. Adults Year Recovered Number Year Banded 67 1966 1967 1968 1969 1970 1971 1972 1973 1974 160 124 144 150 25 179 83 124 143 2 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 6 4 2 3 7 3 4 5 4 2 2 3 2 0 0 1 4 2 0 4 1 0 1 2 0 6 8 0 0 0 3 0 2 3 3 0 1 0 1 0 5 2 1 3 1 0 0 0 0 4 0 6 1 0 0 0 0 0 2 0 2 2 0 0 0 0 0 2 1 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 Subadults Year Recovered Number Year Banded 67 1966 1967 1968 1969 1970 1971 1972 1973 1974 147 75 61 29 4 97 19 37 53 6 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 6 0 4 0 2 5 2 1 2 4 0 0 2 2 0 1 2 1 0 0 0 0 2 2 0 0 2 0 0 3 1 1 1 0 0 0 0 3 0 0 2 1 0 0 0 0 1 0 2 1 0 1 0 0 0 1 0 2 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 1 1 �171 Table A-11. Recovery matrix for male mallards banded during winter within the Gunnison River management unit, Colorado. Adults Year Recovered Number Year Banded 74 75 76 1973 1974 1975 1976 19n 1978 1979 1980 1981 1982 140 157 241 165 245 295 64 153 100 99 3 5 6 1 10 10 rr 2 4 3 4 78 79 80 81 82 83 84 85 86 87 88 89 0 2 6 2 12 0 2 1 .3 5 13 3 1 4 3 5 7 4 0 0 3 3 3 2 2 4 0 0 5 1 1 6 1 5 4 0 0 0 0 0 1 1 3 3 4 0 0 0 0 2 1 1 2 1 2 0 0 0 1 0 0 0 1 1 2 0 0 0 0 0 0 0 0 0 2 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 Subadults Year Recovered Number Year Banded 74 75 76 1973 1974 1975 1976 19n 1978 1979 1980 1981 1982 161 271 274 313 307 232 42 159 45 103 7 8 13 rr 78 79 80 81 82 83 84 85 86 87 88 89 1 3 1 9 5 4 10 14 10 13 7 9 1 0 3 0 2 0 6 3 8 6 16 10 2 0 0 0 2 1 1 2 11 0 1 0 2 4 2 2 5 2 0 0 0 1 2 3 2 3 3 5 0 0 0 1 0 1 0 2 1 6 0 0 0 0 1 1 0 1 1 1 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 �172 Table A-12. Recovery matrix for male mallards banded during winter within the Colorado Adults Year Recovered Number Year Banded 74 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 167 236 155 253 484 209 240 236 118 100 2 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 1 4 2 6 9 0 6 3 11 0 1 5 7 21 1 2 1 3 19 10 0 3 2 4 8 4 17 1 1 1 4 7 3 4 5 0 0 1 4 5 3 5 8 5 0 0 0 0 2 2 2 6 1 6 1 0 0 0 2 3 2 7 4 3 0 0 0 1 0 0 0 4 2 2 0 0 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 Subadults Year Recovered Number Year Banded 74 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 113 267 92 168 408 339 258 245 82 100 4 75 76 77 3 7 2 6 3 0 9 1 4 78 79 80 81 82 83 84 85 86 87 88 89 1 3 5 7 19 . 0 3 0 3 15 15 0 2 0 3 6 11 18 2 0 0 4 9 5 8 12 0 1 0 0 3 7 5 5 4 0 1 0 0 3 6 3 9 6 4 0 0 0 0 1 4 1 7 2 4 0 0 0 1 2 2 1 1 2 1 0 0 0 1 2 1 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 River management unit, Colorado. �173 Table A-13_ Colorado. Recovery matrix for female mallards banded during winter within the Sterling-Julesburg management unit, Adults Year Recovered . Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 24 75 71 68 121 83 0 150 143 204 176 195 143 128 175 119 58 125 125 88 75 0 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 1 0 0 0 1 2 1 0 0 0 0 0 0 0 0 2 0 0 1 0 1 2 0 2 4 0 0 0 1 0 1 0 0 3 2 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 2 1 3 3 0 0 0 0 0 0 0 1 0 0 1 0 3 1 0 0 0 0 0 0 0 0 0 0 2 0 1 0 4 0 0 0 0 0 0 0 0 0 0 1 0 0 1 3 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 3 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 3 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O. 0 0 0 0 0 1 3 1 3 Subadults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 47 64 221 293 264 59 0 93 191 96 262 219 127 158 104 125 107 124 125 139 111 2 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 0 3 0 0 4 0 0 4 7 0 0 1 4 5 0 0 1 2 5 1 0 0 1 4 5 0 0 0 0 1 3 1 0 0 3 1 0 1 0 2 2 0 3 5 0 0 0 2 1 0 0 3 3 2 0 0 0 0 0 0 0 0 1 2 3 0 0 0 0 0 0 0 0 0 1 2 4 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 1 1 2 1 5 0 0 0 0 0 0 0 0 0 0 0 1 1 2 1 0 0 0 0 0 0 0 0 0 0 1 0 0 2 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 3 2 3 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 1 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 �174 Table A-14. Colorado. Recovery matrix for female mallards banded during winter within the Ft. Morgan-Sterling management unit, Adults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 72 143 213 109 253 237 72 238 265 246 212 136 216 125 63 86 116 157 155 137 120 81 0 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 0 4 0 1 4 0 2 2 2 1 0 0 1 2 0 1 1 0 3 7 0 0 1 0 4 2 2 0 0 2 1 2 2 1 4 0 0 0 0 2 1 0 3 6 0 0 0 0 1 0 0 2 2 4 0 0 0 0 0 0 0 1 1 2 6 0 0 0 0 0 0 0 0 1 1 4 2 0 0 0 0 0 0 1 0 0 2 3 1 3 0 0 0 0 0 0 0 0 0 1 0 0 2 2 0 0 0 0 0 0 0 0 0 1 1 0 2 1 1 0 0 0 0 0 0 0 0 1 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Subadults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 91· 61 285 118 260 165 239 191 200 206 173 222 234 179 60 120 93 84 93 108 111 116 2 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 0 0 1 2 2 0 1 5 6 0 0 0 3 3 0 0 0 1 8 1 0 0 3 0 1 4 3 0 0 0 0 0 2 6 6 0 0 1 0 3 1 2 2 2 0 0 1 0 0 0 2 2 3 2 0 0 0 0 0 0 1 1 0 5 1 0 0 0 0 1 0 1 1 1 4 3 4 0 0 0 0 1 0 0 0 0 1 3 0 5 0 0 0 0 0 0 1 0 0 1 0 0 1 2 0 0 0 0 0 0 0 1 1 0 0 0 1 1 0 0 0 0 0 1 0 0 0 0 1 0 2 4 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 2 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 �175 Table A-15. Colorado. Recovery matrix for female mallards banded during winter within the Greeley-Ft. Morgan management unit, Adults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 19n 1978 1979 1980 1981 1982 1983 43 103 170 152 174 138 104 192 160 273 146 155 198 48 63 154 126 111 95 69 143 65 66 67 68 69 70 71 72 73 74 75 76 rr 78 79 80 81 82 83 84 85 86 87 88 89 0 2 0 2 4 1 1 2 4 0 0 0 2 3 1 0 1 4 2 2 0 1 2 1 4 2 1 0 0 1 0 1 1 1 3 0 0 0 0 2 0 1 3 6 0 0 0 0 0 1 2 2 4 3 0 0 0 0 0 0 0 1 1 3 3 0 0 0 1 0 0 0 1 0 1 2 2 0 2 0 0 0 0 0 0 0 2 0 0 4 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 1 2 2 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 3 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Q 0 0 0 0 0 0 0 0 1 0 0 2 1 1 2 0 Subadults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 19n 1978 1979 1980 1981 1982 1983 71 124 218 278 321 147 186 210 223 148 241 156 205 65 50 133 117 134 108 62 88 2 65 66 67 68 69 70 71 72 73 74 75 76 rr 78 79 80 81 82 83 84 85 86 87 88 89 0 1 0 1 7 2 2 1 6 1 2 6 6 7 0 1 2 3 5 3 0 0 2 1 5 3 3 0 0 0 3 1 2 2 4 0 0 0 0 1 0 0 2 6 0 0 0 0 1 0 0 3 3 2 0 0 0 0 0 0 0 0 1 1 3 0 0 0 0 0 1 0 2 3 2 1 5 0 0 0 0 0 0 1 0 3 1 0 1 5 0 0 0 0 0 0 1 0 0 0 2 2 2 1 0 0 0 0 0 0 0 0 1 0 1 1 1 1 1 0 0 0 0 0 0 1 0 0 0 0 1 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 2 2 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 �176 Table A-16. Colorado. Recovery matrix for female mallards banded during winter within the Northern Foothills management unit, Adults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 70 117 188 210 253 203 111 145 160 260 109 252 169 155 233 111 46 105 139 136 133 121 2 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 0 6 0 1 1 0 1 4 3 0 1 0 0 6 0 0 2 0 4 4 0 1 1 3 1 4 5 0 0 0 2 4 2 0 8 0 0 0 1 0 4 1 2 2 0 0 0 1 2 0 0 2 2 8 0 0 0 0 0 0 0 1 0 3 2 0 0 0 0 0 1 0 0 1 4 2 4 0 0 0 0 0 0 0 0 0 3 1 4 1 0 0 0 0 0 0 1 0 0 3 0 2 1 0 0 0 0 0 0 0 0 0 0 1 0 0 1 3 3 0 1 0 0 1 0 0 0 0 1 1 2 0 3 2 3 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 3 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Subadults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 122 156 244 224 344 87 177 136 255 83 174 149 132 124 136 86 46 76 100 98 106 65 3 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 0 1 0 0 4 1 1 3 6 0 1 1 5 7 0 1 2 3 5 1 0 0 2 1 4 1 3 0 1 1 0 0 0 2 3 0 0 0 1 0 1 1 1 12 0 0 0 0 0 0 2 1 4 3 0 0 0 0 0 1 3 0 1 2 4 0 0 0 0 0 0 1 1 1 0 2 9 0 0 0 0 0 0 0 1 2 0 2 1 2 0 0 0 0 0 0 0 0 0 0 2 1 2 5 0 0 0 0 0 0 0 0 0 0 1 1 2 2 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 �177 Table A-17. Colorado. Recovery matrix for female mallards banded during winter within the Southern Foothills management unit, Adults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 19n 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 143 127 129 179 180 171 3 111 133 322 204 242 305 188 231 148 200 144 107 84 113 167 4 65 66 67 68 69 70 71 rz 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 2 0 0 1 1 0 1 4 2 1 0 0 2 4 0 0 0 0 1 3 0 0 0 1 1 3 0 0 0 0 2 2 1 0 1 0 0 0 0 1 2 0 4 2 1 0 0 0 0 1 0 0 2 5 0 0 0 1 0 0 0 0 0 3 7 0 0 0 0 0 0 0 0 0 2 3 3 0 0 0 1 0 0 0 1 0 3 1 3 4 0 0 0 0 0 0 0 0 0 2 0 0 0 4 0 0 0 0 0 0 0 0 1 2 0 0 3 3 7 0 0 0 0 0 0 0 0 0 0 1 0 5 1 1 2 0 0 0 0 0 0 0 0 0 0 0 1 1 1 2 0 1 0 0 0 0 0 0 0 0 0 0 1 0 1 1 1 1 2 3 0 0 0 0 0 0 0 0 0 0 0 1 0 0 3 0 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 2 2 1 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 0 2 2 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 Subadults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 19n 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 132 142 182 218 281 106 7 169 308 158 165 264 3n 196 205 246 202 145 136 107 130 182 2 65 66 67 68 69 70 71 rz 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 2 2 1 2 2 0 0 1 9 1 1 0 0 3 1 0 1 3 7 4 0 1 0 3 4 3 0 0 0 0 1 3 1 0 4 0 0 0 1 0 1 0 4 6 0 0 0 0 2 1 0 0 8 0 0 0 1 0 0 0 0 3 1 2 4 0 0 0 1 1 0 0 0 4 1 1 9 0 0 0 0 0 0 0 1 0 1 0 3 9 0 0 0 0 0 0 0 1 0 0 2 2 5 5 0 0 0 0 0 0 0 0 0 0 2 2 3 0 5 0 0 0 0 0 0 0 0 0 0 0 1 0 2 2 5 0 0 0 0 0 0 0 0 0 0 0 0 0 4 1 1 4 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 6 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 2 1 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 2 2 0 1 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 �178 Table A-18. Colorado. Recovery matrix for female banded mallards during winter within the Bonnl! Reservoir management unit, Adults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 24 160 162 148 186 153 155 129 246 148 235 219 148 203 348 247 428 325 178 92 197 123 74 65 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 0 1 0 2 1 1 2 0 2 0 1 1 2 3 0 3 1 1 2 0 0 0 0 0 2 2 5 0 0 0 0 0 5 2 4 0 0 0 0 3 1 1 3 5 0 0 0 0 0 1 0 1 4 2 0 0 0 0 1 0 1 0 0 1 0 0 0 0 0 0 1 0 1 1 2 1 2 0 0 0 0 0 0 0 0 0 0 0 3 2 0 0 0 0 0 0 0 0 0 0 2 1 1 3 0 0 0 0 0 0 0 0 0 0 1 1 1 2 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 4 0 0 0 0 0 0 0 0 0 0 0 0 1 1 2 1 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 4 2 0 0 0 0 0 0 0 1 0 0 0 1 0 0 2 0 5 4 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 Subadults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 48 87 215 315 299 120 184 216 249 116 147 264 197 315 149 232 356 233 144 136 93 113 80 54 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 1 0 0 0 7 0 1 2 7 0 0 0 6 4 0 0 2 6 2 4 0 0 1 1 3 1 1 0 0 0 2 1 0 2 6 0 1 0 1 2 1 1 4 3 0 0 0 0 1 0 1 0 1 1 0 0 0 0 2 0 0 0 2 0 2 0 0 0 0 1 0 2 0 2 1 2 6 0 0 0 0 0 0 0 0 3 1 0 1 0 0 0 0 0 0 0 0 1 0 1 5 0 0 0 0 0 0 0 0 0 0 0 3 1 5 2 0 0 0 0 0 0 0 0 0 0 0 2 0 1 0 4 0 0 0 0 0 0 0 0 0 0 0 1 0 2 0 3 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 6 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 3 5 2 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 2 0 2 4 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 4 3 4 o . 0 0 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 �179 Table A-19. Recovery matrix for female mallards banded during winter within management unit 10, Colorado. Adults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 44 0 52 0 34 62 0 0 0 13 0 0 0 0 0 0 0 0 0 0 32 0 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 0 0 1 0 1 1 0 2 0 1 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 83 84 85 86 87 88 89 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 81 " 82 Subadults Year Recovered Number Year Banded 64 1963 1964 1965" 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 91 0 129 0 37 122 0 0 0 29 0 0 0 0 0 0 0 0 0 0 56 2 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 0 0 0 0 3 0 0 2 0 0 0 0 0 0 0 0 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 2 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 �180 Table A-20. Recovery matrix for female mallards banded during winter within management unit 11, Colorado. Adults Year Recovered Number Year Banded 64 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 19n 1978 1979 1980 1981 1982 1983 65 66 17 0 0 108 59 191 88 214 82 73 122 6 30 44 153 0 0 26 67 68 69 70 71 72 73 74 75 76 rr 78 79 80 81 82 83 84 85 86 87 88 89 0 1 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 2 0 0 0 0 0 0 0 1 0 0 0 1 1 0 4 0 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Subadults Year Recovered Number Year Banded 64 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 19n 1978 1979 1980 1981 1982 1983 10 0 0 139 36 145 47 83 228 98 249 25 93 157 55 0 0 10 65 66 67 68 69 70 71 72 73 74 75 76 rr 78 79 80 81 82 83 84 85 86 87 88 89 0 1 0 0 0 0 0 0 0 1 1 0 0 2 1 0 0 0 1 0 6 0 0 0 0 0 2 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 3 0 0 0 0 1 0 1 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 2 0 1 4 0 0 0 0 0 0 0 0 0 1 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (J 0 4 �181 Table A-21. Recovery matrix for female mallards banded during winter within management unit 12, Colorado. Adults Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976. 19n 1978 1979 1980 1981 1982 1983 61 0 81 138 132 16 55 188 0 65 66 67 68 69 70 71 72 73 74 75 76 rr 78 79 80 81 82 83 84 85 86 87 88 89 2 0 1 0 1 1 0 1 2 0 0 0 1 3 0 0 1 1 1 0 0 0 0 1 2 0 0 0 0 0 0 0 0 0 1 1 0 1 0 0 0 2 2 1 0 0 0 0 0 0 0 2 1 2 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 rr 96 6 12 73 3 73 4 27 0 0 0 132 Subadul ts Year Recovered Number Year Banded 64 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 19n 1978 1979 1980 1981 1982 1983 rr 0 54 103 144 31 95 152 42 102 4 11 127 10 80 3 7 0 0 0 224 65 66 67 68 69 70 71 72 73 74 75 76 rr 78 79 80 81 82 83 84 85 86 87 88 89 0 0 1 0 1 0 0 0 4 0 0 O· 0 5 0 0 0 2 3 0 0 0 0 0 0 0 2 0 0 0 0 1 0 1 2 0 0 0 0 2 0 1 0 1 0 0 0 0 0 0 0 0 1 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 �182 Table A-22. Recovery matrix for female mallards banded during winter within management unit 13, Colorado. Adults Year Recovered Number Year Banded 67 1966 1967 1968 1969 1970 1971 19n 1973 1974 115 71 82 39 7 74 27 91 56 2 68 69 70 71 72 73 0 1 1 2 1 0 0 0 0 1 0 1 0 0 0 0 0 0 0 1 0 1 0 0 0 4 1 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 0 0 0 0 0 0 0 . 0 0 0 0 0 0 0 2 0 1 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Subadults Year Recovered Number Year Banded 67 1966 1967 1968 1969 1970 1971 19n 1973 1974 163 41 35 11 2 96 4 29 48 4 68 69 70 71 rz 2 2 0 0 0 1 1 0 0 0 0 1 0 0 1 0 1 0 0 0 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 �183 Table A-23. Colorado. Recovery matrix for female mallards during banded winter within Adults Year Recovered Number Year Banded 74 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 133 63 263 62 130 134 68 14547 92 5 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 0 1 0 0 6 2 1 4 2 1 0 3 2 0 0 0 0 0 2 2 1 1 1 1 2 2 4 0 1 0 0 1 0 0 3 0 0 1 0 0 0 0 1 2 0 0 0 0 0 0 0 1 2 4 0 0 0 0 0 0 0 2 0 1 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Subadults Year Recovered Number Year Banded 74 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 162 277 287 177 239 148 98 142 71 105 3 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 1 8 1 5 2 2 3 5 1 3 3 4 6 0 0 1 1 4 3 1 0 4 2 2 4 1 1 0 1 0 2 1 2 5 1 2 1 0 1 0 0 2 2 0 0 0 0 1 0 1 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 2 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 '6 the Gunni son River management uni t I �184 Table A-24. Colorado. Recovery matrix for female mallards banded during winter within Adults Year Recovered Number Year Banded 74 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 141 140 98 180 301 86 135 222 99 67 3 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 2 1 2 4 3 0 1 2 9 0 0 1 2 8 0 0 1 3 1 6 0 0 0 0 4 0 4 0 0 0 1 3 0 3 4 0 1 0 0 3 1 0 3 1 0 0 0 0 0 1 0 2 1 0 0 0 0 0 0 1 1 3 1 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 O. Subadults Year Recovered Number Year Banded 74 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 82 446 90 180 259 346 294 189 101 132 2 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 1 9 2 7 2 1 6 1 3 0 3 2 4 10 1 2 0 0 5 4 0 1 0 1 3 9 7 0 1 0 1 0 4 4 2 0 0 1 0 0 1 2 3 1 0 0 0 1 3 2 1 2 0 7 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 , 0 1 3 1 4 the Colorado River management unit, �185 Table B-1. Distribution of direct recoveries (expressed as a percent) for mallards banded during winter within the Sterling-Julesburg management unit, Colorado from 1963-83. Adult Male Georgia Atlantic Flyway IIIinois Iowa Louisiana Mississippi Missouri Tennessee Mississippi Flyway Total (percent) Total Recovered Female 1.6 1.6 0.8 3.3 1.8 1.8 3.6 3.3 3.3 0.8 7.1 3.6 7.1 14.3 1.6 2.4 11.4 60.3 57.1 33.3 1.6 13.5 14.3 75.4 Total birds 0.3 0.3 1.8 Colorado Kansas Montana Nebraska North Dakota South Dakota Texas Wyoming High Plains - Central Flyway Alberta Manitoba Ontario Quebec Saskatchewan Canada and Alaska Male 0.8 0.8 0.8 3.2 3.2 0.8 Wyoming Pacific Flyway Female 0.8 0.8 Kansas Nebraska North Dakota Oklahoma South Dakota Texas Low Plains - Central Flyway Arizona Cal ifornia Colorado Idaho Montana Oregon Utah Washington Subadult 71.4 3.3 18.7 0.8 4.9 0.8 0.8 62.6 5.4 3.6 1.8 3.6 8.9 21.4 1.8 1.8 10.7 1.8 3.6 41.1 1.8 43.5 0.3 2.1 15.0 0.3 1.8 0.6 0.9 64.6 1.6 1.8 1.8 3.6 1.8 1.8 1.8 5.7 1.8 16.1 0.3 5.7 0.8 2.4 0.8 2.4 3.0 2.7 0.6 0.3 1.5 1.5 9.6 0.3 0.3 0.6 0.6 1.8 0.6 0.3 0.9 0.8 0.8 0.8 0.3 0.3 1.2 0.3 0.3 0.3 2.7 7.9 7.1 8.9 0.8 0.8 21.4 1.8 0.8 4.0 12.7 7.1 14.3 6.5 17.1 5.4 28.6 10.5 0.6 0.3 0.3 5.4 17.1 100.0 126 100.0 28 100.0 123 100.0 56 100.0 333 �186 Table B-2_ Distribution of indirect recoveries (expressed as a percent) for mallards banded during winter within the Sterling-Julesburg management unit, Colorado from 1963-83. Adult Subadult Male Female Male Female Arkansas IIIinois Iowa Kentucky louisiana Minnesota Mississippi Missouri Tennessee Mississippi Flyway 1.2 0.3 1.6 1.9 0.3 0.3 1.1 2.4 4.7 Kansas Nebraska North Dakota Oklahoma South Dakota Texas low Plains - Central Flyway 1.8 0.9 1.2 0.6 1.6 Colorado Kansas Montana Nebraska New Mexico North Dakota South Dakota Texas Wyoming High Plains - Central Flyway 55.7 0.9 0.6 14.7 1_6 1.6 0.9 0.3 0.3 1.2 5.8 0.9 0.6 0.6 3.1 77.1 Colorado Idaho Montana Oregon Utah lJashington Wyoming Pacific Flyway 0.6 0.3 0.6 Alberta British Columbia Manitoba Ontario Saskatchewan Canada and Alaska Total (percent) Total Recovered 1.1 0.3 1.1 3.1 4.7 59.4 9.4 3.1 1.6 . 73.4 0.3 3.7 1.9 1.6 0.9 0.6 0.6 2.2 7.8 45.6 0.3 1.9 16.3 0.3 0.3 0.6 1.3 1.6 68.1 3.3 1.1 3.3 2.2 6.6 33.0 3.3 17.6 3.3 3.3 4.4 64.8 Total birds 1.5 0.2 0.2 0.1 0.5 0.1 0.1 0.2 0.1 3.2 1.6 1.1 1.5 0.5 0.2 1.6 6.6 49.4 0.5 1.4 15.2 0.1 0.9 1.1 0.9 2.4 71.8 1.6 1.6 0.3 0.3 2.1 0.9 0.9 0.3 0.3 0.3 0.9 3.1 3.7 7.0 14.1 0.9 9.7 0.3 0.3 4.6 12.5 14.1 6.2 16.6 1.1 5.5 25.3 10.0 0.1 0.5 0.1 5.0 15.7 100.0 327 100.0 64 100.0 320 100.0 91 100.0 802 0.6 0.5 0.5 0.2 0.1 0.5 0.1 2.6 18.7 �187 Table B-3. Distribution of direct recoveries (expressed as a percent) for mallards banded during winter within the Ft. Morgan-Sterling management unit, Colorado from 1963-84. Adult Male Arkansas IIIinois Iowa Louisiana Mississippi Missouri Mississippi Flyway 0.6 0.6 0.6 · Subadult Female Male Female 1.7 0.6 6.0 1.7 0.6 0.6 1.9 3.4 Kansas Nebraska North Dakota Oklahoma South Dakota Texas Low Plains - Central Flyway 1.3 1.3 2.6 0.6 3.4 3.4 5.8 12.1 Colorado Kansas Montana Nebraska New Mexico North Dakota South Dakota Wyoming High Plains - Central Flyway 59.6 0.6 1.3 5.1 53.4 0.6 0.6 3.2 71.2 1.7 Arizona Cal Hornia Colorado Idaho Montana Oregon Utah Washington Pacific Flyway Alberta British Columbia Manitoba Saskatchewan Canada and Alaska Total (percent) Total Recovered · 3.4 1.7 0.6 2.5 2.5 2.5 1.2 0.6 2.5 9.2 2.0 2.0 10.0 2.0 2.0 42.9 1.2 24.0 13.5 0.6 1.2 3.1 3.1 65.6 16.0 4.0 4.0 4.0 52.0 1.3· 0.6 2.0 0.6 0.6 1.8 1.8 1.2 0.6 1.2 7.4 4.0 2.0 1.7 8.6 1.7 67.2 0.6 · 3.2 2.0 10.0 Total Birds 1.2 0.2 0.7 0.7 0.2 0.2 3.3 2.1 1.9 1.4 0.9 0.2 0.9 7.5 48.2 0.7 0.7 10.1 0.2 1.4 1.9 3.0 66.3 0.2 0.5 0.5 1.4 1.2 0.5 0.2 0.7 5.2 17.2 9.2 7.1 17.9 17.2 1.2 4.9 15.3 10.0 26.0 11.5 0.2 0.5 5.6 17.8 100.0 156 100.0 58 100.0 163 100.0 50 100.0 427 10.9 14.0 2.0 �188 Table B-4_ Distribution of indirect recoveries (expressed as a percent) for mallards banded during winter within the Ft. Morgan-Sterling management unit, Colorado from 1963-84. Adult Male Subadult Female North Carol ina Atlantic Flyway 0.2 0.2 Arkansas Illinois Iowa Louisiana Minnesota Mississippi Missouri Wisconsin Mississippi Flyway 0.8 1.2 0.4 1.2 1.2 0.2 0.2 0.2 1.8 Kansas Nebraska North Dakota Oklahoma South Dakota Texas Low Plains - Central Flyway 0.6 0.8 0.4 Colorado Kansas Montana Nebraska New Mexico North Dakota South Dakota Texas Wyoming High Plains - Central Flyway 62.8 0.6 0.8 10.1 0.6 0.6 0.4 1.2 1.2 78.4 Colorado Idaho Montana Oregon Utah Washington Wyoming Pacific Flyway Alaska Alberta British Columbia Manitoba Saskatchewan Canada and Alaska 0.6 0.8 3.2 0.2 0.6 0.8 9.5 0.2 0.4 4.4 14.5 1.1 0.2 0.2 0.5 0.2 0.5 0.5 6.4 3.7 3.2 8.3 2.4 1.2 0.7 2.3 0.7 0.7 0.5 2.3 7.0 1.8 1.8 0.9 0.9 53.6 0.2 1.1 11.3 0.5 0.2 0.5 0.7 1.4 69.4 47.7 2.4 6.1 62.2 1.2 7.3 1.2 n.o 1.2 0.9 1.6 0.7 0.9 0.9 1.8 7.3 0.9 4.6 0.9 1.8 0.9 1.8 58.7 1.8 0.9 0.9 0.9 6.1 0.5 0.5 0.2 4.3 4.6 6.1 7.9 0.9 15.6 6.1 12.2 0.5 7.7 16.0 4.6 21.1 Mexico Total (percent) Total Recovered Female 0.2 100.0 495 Total birds 0.1 0.1 1.2 3.7 0.2 1.8 Male 100.0 82 100.0 444 1.5 0.1 0.1 0.5 0.3 0.3 0.3 0.1 3.1 0.7 1.4 0.7 0.4 0.4 1.6 5.3 57.7 0.4 1.0 9.8 0.4 0.4 0.6 0.9 1.2 n.5 0.4 1.2 0.7 0.1 0.4 0.4 0.2 3.4 0.1 9.2 0.1 0.4 5.8 15_6 0.1 100.0 109 100.0 1130 �189 Table B-5. Distribution of direct recoveries (expressed as a percent) for mallards banded during winter within the Greele~-Ft. Morgan management unit, Colorado from 1963-83. Adult Male Arkansas Iowa Louisiana Mississippi Missouri Mississippi Flyway Kansas Nebraska North Dakota Oklahoma South Dakota Texas Low Plains - CentraL Flyway Colorado Kansas Montana Nebraska New Mexico South Dakota Texas Wyoming High Plains - Central Flyway Cal Hornia CoLorado Idaho Montana Oregon Utah Washington gyoming Pacific FLyway Alberta British Columbia Manitoba Ontario Saskatchewan Canada and Alaska Total (percent) Total Recovered Subadult Female Male 0.7 1.3 2.0 2.4 0.8 0.8 0.8 2.0 2.0 4.8 0.8 0.8 3.2 1.3 Female 1.6 1.6 3.2 4.8 1.6 2.0 Total birds 0.8 0.5 1.3 0.3 0.3 3.1 1.0 0.3 1.3 0.8 0.5 0.3 4.1 1.3 2.0 4.8 3.2 1.6 11.1 69.5 56.9 0.7 2.6 11.8 42.4 1.6 1.6 9.6 46.0 1.6 1.6 3.2 55.4 0.8 1.0 6.2 3.2 55.6 0.3 0.8 0.3 2.3 66.9 0.8 1.6 0.7 1.3 74.8 0.7 1.3 2.0 2.0 2.0 n.5 . 2.0 2.0 0.7 3.2 60.8 · 1.6 1.6 2.4 2.4 0.8 1.6 0.8 3.2 1.6 1.6 0.3 0.5 1.5 2.1 0.3 1.3 0.5 0.3 6.7 0.7 5.3 3.9 8.0 · 9.5 10.6 17.6 12.0 0.8 12.7 1.6 5.3 16.6 2.0 19.6 8.8 21.6 · 1.6 4.8 20.6 12.3 0.5 0.3 0.3 5.9 19.2 100.0 151 100.0 51 100.0 125 100.0 63 100.0 390 0.7 �190 Table B-6. Distribution of indirect recoveries (expressed as a percent) for mallards banded during winter within the Greele:x:-Ft.Morgan management unit, Colorado from 1963-83. Adult Male Subadult Female Male New York Atlantic Flyway Arkansas Iowa Louisiana Michigan Minnesota Mississippi Mississippi Flyway Kansas Nebraska North Dakota Oklahoma South Dakota Texas Low Plains - Central Flyway 0.5 0.5 1.1 0.3 0.3 0.5 3.3 Colorado Kansas Montana Nebraska New Mexico North Dakota Oklahoma South Dakota Texas Wyoming High Plains - Central Flyway 61.5 0.5 0.8 9.1 0.3 0.3 0.3 0.5 0.8 1.1 75.3 Arizona Cal itornia Colorado Idaho Montana Oregon Utah Washington Pacific Flyway Alaska Alberta British Columbia Manitoba Ontario Saskatchewan Canada and Alaska Total (percent) Total Recovered 0.1 0.1 0.8 0.9 0.9 2.7 0.3 0.3 2.1 4.5 0.4 0.2 0.7 0.1 0.2 0.2 1.9 1.1 0.3 0.3 1.1 0.3 0.5 0.3 1.1 1.4 3.6 . 1.1 2.2 1•. 1 1.1 1.1 5.6 56.2 4.5 9.0 0.3 1.1 1.6 0.8 0.3 1.3 5.3 56.6 0.3 0.8 8.5 0.3 1.1 2.2 73.0 1.1 1.1 1.1 3.4 . Total birds 0.9 0.9 0.8 0.3 0.3 Female 0.9 1.8 2.7 1.8 3.6 10.8 42.3 0.9 2.7 11.7 0.9 0.5 1.3 2.7 71.0 1.8 1.8 3.6 65.8 0.3 0.8 1.9 0.3 0.8 1.3 0.3 5.6 0.9 . 0.9 0.9 2.7 0.9 9.9 0.6 1.0 1.4 0.7 0.2 1.3 5.2 56.8 0.4 1.4 9.1 0.2 0.3 0.1 0.6 1.1 2.1 n.2 0.1 0.4 0.4 1.3 0.9 0.4 0.5 0.2 4.3 8.8 0.3 0.3 13.5 9.6 1.1 7.4 16.8 2.2 16.9 0.3 0.3 5.9 16.0 3.6 15.3 0.1 9.7 0.1 0.4 0.1 5.9 16.3 100.0 364 100.0 89 100.0 376 100.0 111 100.0 940 0.9 �191 Table B-7. Distribution of direct recoveries (expressed as a percent) for mallards banded during winter within the Northern Foothills management unit, Colorado from 1963-1984. Adult Male Arkansas Illinois Iowa Louisiana Minnesota Missouri Mississippi Flyway Kansas Nebraska North Dakota Oklahoma South Dakota Texas Low Plains - Central Flyway Colorado Kansas Montana Nebraska New Mexico North Dakota South Dakota Texas lJyoming High Plains - Central Flyway Arizona California Colorado Idaho Montana Utah Washington Pacific Flyway Alberta British Columbia Manitoba Saskatchewan Canada and Alaska Total (percent) Total Recovered Subadult Female Male 1.5 1.5 0.7 3.0 3.0 . 0.7 1.5 1.5 3.0 0.7 0.7 0.7 0.7 2.2 2.2 7.5 n.7 65.7 51.5 0.7 4.9 0.7 0.7 0.7 0.7 2.1 83.2 1.5 4.5 0.7 5.2 0.7 0.7 2.2 0.7 Female 3.0 74.6 3.7 64.9 1.4 2.7 40.5 1.4 1.4 9.5 66.7 2.7 1.4 33.3 5.4 62.2 100.0 4.5 9.1 . 0.7 6.0 12.7 13.5 1.4 3.5 13.3 9.0 14.9 0.7 1.5 14.9 6.8 21.6 100.0 143 100.0 67 100.0 134 100.0 74 1.5 . 0.5 0.2 0.7 0.2 1.0 1.0 3.6 1.4 1.4 3.0 Total birds 0.5 0.2 0.2 0.5 0.5 0.2 2.1 1.4 1.4 1.5 0.7 0.7 2.2 1.5 1.5 1.5 9.7 0.7 0.7 Male 0.7 0.7 0.7 0.7 0.7 1.4 Unknown 59.1 0.2 1.0 5.7 0.5 1.2 1.2 0.2 3.3 72.4 0.5 0.2 1.2 1.7 1.2 0.7 1.0 6.4 1.4 4.1 2.7 1.4 2.7 12.2 10.5 0.2 0.5 4.3 15.4 100.0 3 100.0 421 �192 Table B-8. Distribution of indirect recoveries (expressed as a percent) for mallards banded during winter within the Northern Foothills management unit, Colorado from 1963-84. Adult Male Subadult Female Male South Carolina Atlantic Flyway Arkansas Illinois Iowa louisiana Minnesota Missouri Mississippi Flyway 0.2 Kansas Nebraska North Dakota Oklahoma south Dakota Texas low Plains - Central Flyway 0.5 0.2 0.5 0.2 0.2 0.2 1.9 Colorado Montana Nebraska New Mexico North Dakota South Dakota Texas Wyoming High Plains - Central Flyway 79.8 1.0 2.6 0.2 Cal ifornia Colorado Idaho Montana Nevada Oregon Utah lJashington Wyoming Pacific Flyway Alaska Alberta Manitoba Saskatchewan Canada and Alaska Total (percent) Total Recovered 0.2 1.8 1.8 0.9 0.9 0.9 2.8 65.1 2.8 2.8 0.9 0.2 1.4 85.2 3.7 75.2 . 0.2 0.2 0.5 1.8 0.9 0.9 1.6 0.3 0.3 1.1 0.8 0.5 4.6 0.5 1.4 0.3 0.3 0.3 0.8 3.5 63.4 1.9 4.9 0.8 0.3 0.3 2.2 73.7 Unknown Female 0.1 0.1 1.0 2.1 0.7 0.4 0.3 0.4 0.3 0.2 2.3 3.1 1.0 1.0 16.7 2.1 4.2 16.7 49.0 3.1 4.2 2.1 1.0 3.1 62.5 0.5 0.8 1.4 1.6 1.0 1.0 4.2 1.0 1.0 1.0 9.4 0.9 1.9 4.6 0.3 1.1 1.1 0.3 7.0 11.9 7.0 16.7 3.7 15.6 4.1 11.1 3.1 19.8 100.0 109 100.0 369 100.0 96 100.0 420 Total birds 1.0 1.0 0.5 0.5 0.2 6.0 0.2 4.3 10.7 Male 83.3 83.3 0.5 0.7 0.6 0.2 0.2 0.7 2.9 69.2 1.7 3.6 0.5 0.1 0.4 0.1 2.1 77.7 0.3 0.5 1.2 0.9 0.1 0.2 0.7 0.7 0.2 4.8 0.1 8.0 0.1 4.0 12.2 100.0 6 100.0 1000 �193 Table B-9. Distribution of direct recoveries (expressed as a percent) for mallards banded during winter withing the Southern .Foothills management unit, Colorado from 1963-84. Adult Male Subadult Female Male Female Arkansas Louisiana Mimesota Missouri Mississippi Flyway 0.9 0.4 1.3 0.5 2.2 Kansas Nebraska North Dakota South Dakota Texas Low Plains - Central Flyway 0.4 0.4 1.8 0.4 0.5 1.5 0.5 3.4 4.5 1.1 3.1 3.3 3.3 0.5 3.0 2.2 11.2 Colorado Montana Nebraska New Mexico North Dakota South Dakota Texas Wyoming High Plains - Central Flyway 75.8 2.2 1.8 0.4 0.4 0.4 0.9 2.2 84.1 77.0 1.6 1.6 1.6 68.2 2.0 4.5 0.5 0.5 0.5 51.7 1.1 2.2 3.3 85.2 2.0 78.3 3.4 60.7 Arizona California Colorado Idaho Montana Nevada Utah Washington Wyoming Pacific Flyway Alberta British Columbia District of Mackenzie Manitoba Saskatchewan Canada and Alaska Total (percent) Total Recovered 0.5 . 1.1 1.1 1.1 1.1 0.5 0.4 1.6 1.6 1.6 0.4 0.4 . . 1.3 4.9 6.2 4.9 2.0 2.5 1.1 5.6 1.1 1.1 1.1 Total birds 0.5 0.2 0.2 0.2 1.0 0.9 1.4 1.0 0.2 0.9 4.3 69.6 1.7 2.8 0.5 0.7 0.5 0.3 2.4 78.6 0.2 0.2 1.7 1.4 0.3 0.2 0.5 0.2 0.2 4.9 0.5 0.5 0.5 6.6 10.1 6.6 0.5 9.0 1.1 1.1 4.5 15.7 6.6 0.3 0.2 0.2 3.8 11.1 100.0 89 100.0 575 . 1.6 4.0 10.1 6.6 4.5 11.6 100.0 227 100.0 61 100.0 198 �194 Table B-10. Distribution of indirect recoveries (expressed as a percent) for mallards banded during winter within the Southern Foothills management unit, Colorado from 1963-84.· Adult Male Arkansas Illinois Kentucky louisiana Minnesota Mississippi Missouri Wisconsin Mississippi Flyway Subadult Female 0.2 1.2 3.7 Kansas Nebraska North Dakota Oklahoma South Dakota Texas Low Plains - Central Flyway 0.4 0.2 1.0 0.9 Colorado Kansas Montana Nebraska New Mexico North Dakota South Dakota Texas Wyoming High Plains - Central Flyway 73.4 0.2 1.0 5.3 0.2 0.4 0.4 0.2 2.1 83.2 Total (percent) Total Recovered Male 0.8 1.9 0.9 0.9 Alaska Alberta British Columbia District of Mackenzie Manitoba Saskatchewan Canada and Alaska Female 0.2 1.8 1.9 0.9 3.7 59.3 0.9 0.9 3.7 0.9 3.7 69.4 0.5 2.4 0.2 0.2 1.4 0.8 4.0 0.2 1.1 0.7 0.8 0.8 0.7 1.4 4.1 0.8 0.8 3.2 64.3 54.0 2.0 6.1 0.5 0.2 0.2 1.4 1.4 76.0 0.8 2.4 0.2 0.4 1.2 0.8 0.2 0.2 0.4 0.6 0.2 0.2 4.1 0.5 2.0 2.0 0.9 0.9 . 6.5 0.5 1.4 0.2 4.0 6.8 11.1 13.0 0.9 7.0 0.9 0.8 12.7 0.8 3.5 9.8 2.8 16.7 0.2 3.6 11.8 5.6 19.8 100.0 512 100.0 108 100.0 442 100.0 126 6.1 100.0 100.0 66.7 0.2 1.3 5.1 0.3 0.3 0.3 0.8 2.1 77.0 0.1 0.3 1.1 1.4 1.1 0.1 0.4 0.8 0.7 0.1 6.1 . 2.4 0.9 1.9 0.9 0.9 . 0.3 0.6 0.9 0.1 0.3 0.7 2.9 0.8 0.8 3.2 61.9 Total birds 0.2 0.2 0.1 0.7 0.2 0.2 0.3 0.1 1.8 0.5 0.2 0.2 0.2 0.2 0.2 Arizona Cal ifornia Colorado Idaho Montana Nevada Oregon Utah Washington Wyoming Pacific Flyway Male Unknown 2.4 1.6 0.8 0.1 7.7 0.5 0.1 0.1 3.7 12.2 0.2 100.0 1 100.0 1189 �195 Table B-11. Distribution of direct recoveries (expressed as a percent) for mallards banded during winter within the Bonn~ Reservoir management unit, Colorado from 1963-86. Adult Male Alabama Arkansas Illinois Iowa Louisiana Minnesota Mississippi Missouri Tennessee Mississippi Flyway Kansas Nebraska North Dakota Oklahoma South Dakota Texas Low Plains - Central Flyway Colorado Kansas Montana Nebraska New Mexico North Dakota Oklahoma South Dakota Texas Wyoming High Plains - Central Flyway Subadult Female Male 1.8 1.8 0.6 4.5 0.6 1.9 1.3 0.6 0.6 0.6 0.6 1.3 2.6 1.3 1.3 1.3 2.6 9.0 3.6 0.6 11.0 3.6 3.6 1.8 3.6 9.1 21.8 6.5 6.5 1.9 1.9 3.2 3.9 23.9 54.2 3.9 3.2 6.5 30.9 5.5 1.3 3.6 7.3 1.3 0.6 71.0 47.3 California Colorado Idaho Montana Oregon Utah Pacific Flyway 0.6 Alberta British Columbia Manitoba Saskatchewan Canada and Alaska 9.7 12.7 7.7 17.4 100.0 155 Total (percent) Total Recovered 14.8 1.9 1.3 11.0 1.3 0.6 1.3 1.3 33.5 Unknown Female Male Female 0.2 2.5 0.2 0.9 2.0 0.2 0.7 0.2 0.4 7.4 3.9 7.9 1.3 1.3 1.3 15.8 7.9 6.6 5.3 1.3 33.3 . 7.9 28.9 33.3 66.7 14.5 50.0 2.6 50.0 100.0 0.2 0.2 0.9 1.3 0.4 0.2 3.4 1.3 2.6 1.9 0.6 0.6 5.8 0.6 1.3 4.5 4.5 2.5 1.6 1.6 4.9 19.5 30.5 2.7 1.6 7.6 0.4 1.6 0.2 1.1 0.9 0.4 47.1 3.9 1.3 2.6 1.3 26.3 Total birds 2.6 1.3 5.3 13.2 33.3 1.8 12.7 27.3 13.5 0.6 0.6 11.0 25.8 1.3 9.2 23.7 33.3 12.1 0.2 0.7 9.6 22.6 100.0 55 100.0 155 100.0 76 100.0 3 100.0 446 100.0 2 �196 Table B-12. Distribution of indirect recoveries (expressed as a percent) for mallards banded during winterwithin the Bonn~ Reservoir management unit, Colorado from 1963-86. Adult Male Subadult Female Male Pennsylvania Atlantic Flyway Arkansas Illinois Iowa Louisiana Minnesota Mississippi Missouri Mississippi Flyway 0.6 0.2 0.2 0.6 3.2 Kansas Nebraska North Dakota Oklahoma South Dakota Texas Low Plains - Central Flyway 1.3 2.8 1.7 0.9 1.3 1.3 9.2 Colorado Kansas Montana Nebraska New Mexico North Dakota Oklahoma South Dakota Texas Wyoming High Plains - Central Flyway 45.4 2.2 1.1 10.5 0.9 1.7 0.4 0.6 1.5 1.1 65.4 California Colorado Idaho Montana Oregon Utah Ilashington Wyoming Pacific Flyway Alaska Alberta British Columbia Manitoba Ontario Saskatchewan Canada and Alaska Total (percent) Total Recovered 1.5 2.0 1.0 1.0 4.0 2.0 2.0 5.0 9.0 28.0 6.0 1.0 13.0 2.0 2.0 1.0 1.0 54.0 0.4 Female 9.5 0.2 0.2 Total birds 0.1 0.1 3.6 0.3 1.1 1.4 0.8 0.6 0.8 8.5 3.4 0.9 2.3 0.2 0.4 1.1 0.6 0.3 0.8 5.6 3.6 2.5 2.8 1.1 1.1 4.4 15.4 2.6 1.7 2.6 4.3 28.7 2.8 1.4 15.7 0.3 1.4 0.3 1.1 1.9 0.8 54.3 . 1.7 0.9 0.9 7.8 2.1 2.5 2.0 1.2 1.1 2.8 11.7 1.7 12.9 19.0 3.4 1.7 12.1 0.9 0.9 55.6 22.2 . 3.4 41.4 1.7 0.9 1.0 0.4 0.2 1.3 Male 0.9 0.9 0_3 0.3 2.5 0.3 0.3 0.2 Unknown 77.8 11.1 11.1 1.4 1.7 1.0 5.0 4.3 19.0 1.0 8.0 0.9 19.8 . 2.6 11.0 20.9 12.0 32.0 0.3 8_5 16.8 100.0 465 100.0 100 100.0 363 9.5 32.8 100.0 116 22.2 35.1 2.8 1.2 12.8 0.6 1.5 0.3 0.9 1.8 0.9 57.9 0.1 0.2 1.0 0.5 0.1 0.2 0.9 0.1 3.0 0.1 10.9 0.2 0.4 0.1 10.0 21.7 100.0 9 100.0 1053 �197 Table B-13. Distribution of direct recoveries (expressed as a percent) for mallards banded during winter in Southeast Colorado from 1963-83. Adult Male Arkansas Illinois Iowa Louisiana Missouri Mississippi Flyway 1.4 0.7 3.4 Kansas Nebraska North Dakota Oklahoma South Dakota Texas low Plains - Central Flyway 1.4 0.7 1.4 1.4 0.7 5.5 Colorado Kansas Montana Nebraska New Mexico North Dakota Oklahoma South Dakota Texas Wyoming High Plains - Central Flyway 44.8 1.4 0.7 6.9 0.7 1.4 0.7 0.7 4.1 2.1 63.4 Cal ifornia Colorado Idaho Montana Oregon Washington Wyoming Pacific Flyway Alberta Manitoba Saskatchewan Canada and Alaska Total (percent) Total Recovered 1.4 Subadult Female Male 2.5 2.0 1.0 . Female 2.5 . . 0.7 0.7 0.7 0.7 0.7 0.7 4.1 3.0 5.0 5.0 6.0 5.0 2.5 2.5 1.0 5.0 2.0 1.0 2.0 2.0 13.0 3.3 6.7 1.7 1.7 5.0 18.3 30.0 5.0 3.0 9.0 11.7 3.3 3.3 8.3 3.0 6.0 3.0 59.0 1.7 2.5 2.5 10.0 32.5 2.5 2.5 2.5 40.0 2.5 2.5 2.5 28.3 1.4 0.3 0.3 2.3 0.3 4.6 1.2 3.5 1.2 1.2 2.3 1.2 10.4 33.3 2.6 1.7 7.2 0.6 0.6 0.6 1.2 3.8 1.7 53.3 7.5 7.0 1.7 16.7 0.6 2.3 1.4 1.4 0.9 0.3 0.6 7.5 25.0 21.7 1.7 8.3 31.7 14.2 1.4 8.4 24.1 100.0 60 100.0 345 2.0 1.0 2.0 2.0 13.8 1.4 8.3 23.4 12.5 37.5 6.0 2.0 7.0 15.0 100.0 145 100.0 40 100.0 100 1.7 6.7 3.3 3.3 Total birds �198 Table 8-14. Distribution of indirect recoveries (expressed as a percent) for mallards banded during winter in Southeast Colorado from 1963-83. Adult Male Alabama Arkansas Iowa Louisiana Minnesota Mississippi Missouri Mississippi Flyway Subadult Female Male 0.3 2.1 0.3 1.0 0.3 Female 2.9 1.5 0.3 0.3 0.5 1.5 4.2 2.9 5.8 Kansas Nebraska North Dakota Oklahoma South Dakota Texas Low Plains - Central Flyway 0.8 1.5 2.6 1.5 0.5 1.8 8.7 1.5 1.5 1.7 2.1 1.4 1.4 1.5 0.3 0.7 4.2 9.0 2.9 2.9 2.9 11.6 Colorado Kansas Montana Nebraska New Mexico North Dakota Oklahoma South Dakota Texas Wyoming High Plains - Central Flyway 51.3 1.3 2.0 7.4 1.0 0.5 52.2 27.5 0.5 4.6 1.0 69.6 1.5 3.0 36.8 0.7 1.0 8.3 1.0 0.7 0.3 2.1 3.8 3.1 58.0 California Colorado Idaho Montana Nevada Oregon Utah Washington Pacific Flyway Alberta British Columbia Manitoba Saskatchewan Canada and Alaska Total (percent) Total Recovered 4.5 9.0 1.5 9.0 67.2 0.3 1.0 0.5 1.8 1.5 0.8 0.3 4.6 1.5 7.1 14.9 0.3 9.2 16.6 100.0 392 2.1 1.7 1.0 0.3 1.4 0.7 1.4 8.7 7.2 2.9 2.9 2.9 4.3 47.8 1.4 1.4 23.2 Total birds 0.1 0.7 0.1 0.7 0.1 0.2 0.2 2.3 1.2 1.7 1.2 1.2 0.7 2.9 9.1 44.2 0.9 1.5 7.8 0.9 0.7 0.1 1.3 4.0 2.0 63.5 0.1 1.2 1.0 1.2 0.1 0.5 0.7 0.6 5.5 1.5 4.5 20.9 9.7 0.3 2.1 8.0 20.1 10.1 33.3 10.0 0.1 1.0 8.5 19.6 100.0 67 100.0 288 100.0 69 100.0 816 �199 Table B-15. Distribution of direct recoveries (expressed as a percent) for mallards banded during winter within the Gunnison River management unit, Colorado from 1973-82. Subadult Adult Male Female Kansas Low Plains - Central Flyway Colorado Kansas Montana Nebraska New Mexico Wyoming High Plains - Central Flyway Arizona Colorado Idaho Montana New Mexico Utah Wyoming Pacific Flyway Alberta Saskatchewan total Total (percent) Total Recovered Male Female 1.1 1.1 5.7 3.1 4.7 7.8 1.6 62.5 4.7 1.6 1.6 7.8 4.7 84.4 0.5 0.5 2.5 2.5 6.9 6.9 79.3 3.4 3.4 . 86.2 1.1 2.3 3.4 12.5 1.1 65.9 3.4 2.3 1.1 5.7 1.1 80.7 4.7 3.1 7.8 6.9 6.9 4.5 1.1 5.7 100.0 64 100.0 29 100.0 88 Total birds 5.0 10.0 3.6 0.5 2.3 0.5 0.9 2.3 10.0 75.0 0.9 66.1 4.1 1.8 0.9 5.9 1.8 81.4 5.0 10.0 15.0 5.0 3.2 8.1 100.0 40 100.0 221 62.5 5.0 7.5 �200 Table S-16. Distribution of indirect recoveries (expressed as a percent) for mallards banded during winter within the Gunnison River management unit, Colorado from 1973-82. Adult Arkansas louisiana Minnesota Missouri Wisconsin Mississippi Flyway Nebraska North Dakota Texas Low Plains - Central Flyway Colorado Montana Nebraska New Mexico North Dakota South Dakota Texas Wyoming High Plains - Central Flyway Colorado Idaho Montana Nevada New Mexico Oregon Utah Washington Wyoming Pacific Flyway Alberta Saskatchewan Canada and Alaska Total (percent) Total Recovered Subadult Male Female 0.8 0.8 2.7 Male 1.4 . 1.4 2.7 0.6 0.6 1.3 2.7 0.6 1.6 2.7 0.6 1.3 5.4 2.7 1.6 Female 2.9 0.8 0.8 0.8 9.3 . 2.7 0.5 0.5 0.3 0.3 0.3 1.8 0.5 0.5 0.3 1.3 1.6 0.8 0.8 Total birds 3.2 0.6 2.5 0.6 1.3 10.1 1.4 2.9 1.4 2.5 10.8 1.4 17.4 53.6 1.4 1.4 5.1 0.5 1.8 0.8 0.5 0.3 0.3 1.5 10.7 60.5 9.3 0.8 62.2. 2.7 0.8 0.8 81.4 2.7 2.7 5.4 2.7 5.4 83.8 60.5 5.7 1.3 0.6 1.3 0.6 7.6 1.3 2.5 81.5 3.9 2.3 6.2 2.7 5.4 8.1 3.8 1.3 5.1 7.2 7.2 4.3 1.8 6.1 100.0 129 100.0 37 100.0 157 100.0 69 100.0 392 . 9.3 1.4 10.1 1.4 2.9 n.5 59.4 5.9 1.0 0.3 1.3 0.5 8.4 1.0 2.3 80.1 �201 Table B-17. Distribution of direct recoveries (expressed as a percent) for mallards banded during winter within the Colorado River management unit, Colorado from 1973-82. Subadult Adult Male Louisiana Mississippi Flyway Female Arizona Colorado Idaho Montana Oregon Utah Washington Wyoming Pacific Flyway Alberta British Columbia Manitoba Saskatchewan Canada and Alaska Total (percent) Total Recovered Female 1.1 1.1 2.2 2.2 1.1 1.1 1.1 0.4 0.4 0.8 4.4 4.3 3.3 2.1 2.6 1.1 1.1 6.7 63.3 5.6 4.4 Total birds 0.4 0.4 1.1 1.1 Nebraska Texas Low Plains - Central Flyway Colorado Kansas Montana Nebraska New Mexico South Dakota Wyoming High Plains - Central Flyway Male 2.6 8.9 4.3 10.6 61.5 7.7 2.2 50.0 13.3 2.2 2.1 55.3 6.4 2.1 8.5 2.1 2.1 78.7 3.0 0.4 1.9 0.4 0.4 0.4 1.1 7.5 1.1 57.1 8.6 2.6 0.4 10.5 0.4 1.9 82.7 11.1 2.6 15.4 8.9 1.1 85.6 87.2 3.3 80.0 4.4 5.1 6.7 2.2 6.7 5.1 10.3 1.1 1.1 8.9 2.1 10.6 5.6 0.4 0.4 2.3 8.6 100.0 90 100.0 39 100.0 90 100.0 47 100.0 266 6.4 2.1 �202 Table 8-18. Distribution of indirect recoveries (expressed as a percent) for mallards banded during winter within the Colorado River management unit, Colorado from 1973-82. Adult Male Arkansas Louisiana Mississippi Flyway Kansas Nebraska Oklahoma .South Dakota Texas Low Plains - Central Flyway Colorado Montana Nebraska New Mexico Texas Wyoming High Plains - Central Flyway Arizona California Colorado Idaho Montana New Mexico Oregon Utah Washington Wyoming Pacific Flyway Alberta British Columbia Manitoba Saskatchewan Canada and Alaska Total (percent) Total Recovered Subadult Female Male Unknown Female Male 1.0 2.0 2.0 0.4 0.2 0.6 1.0 1.0 0.5 0.5 0.4 0.4 0.2 0.2 0.2 1.4 1.1 1.1 0.6 0.6 4.0 1.7 0.6 2.0 1.1 7.5 2.0 64.9 5.7 0.6 2.0 2.0 64.7 3.9 2.0 0.6 7.5 2.0 9.8 1.1 80.5 7.8 94.1 8.6 0.6 0.6 1.7 11.5 2.0 100.0 174 2.1 2.2 4.6 1.5 2.2 1.1 1.1 1.1 2.6 0.5 1.5 10.8 0.5 1.0 60.8 5.2 1.0 1.0 0.5 6.7 1.0 1.5 79.4 1.1 6.7 58.9 3.3 1.1 50.0 50.0 50.0 1.1 13.3 3.3 81.1 4.6 0.5 7.8 2.0 1.5 6.7 2.2 10.0 100.0 51 100.0 194 100.0 90 . Total birds 50.0 3.9 1.4 0.4 1.2 0.2 1.2 8.2 0.4 0.6 62.2 4.9 1.0 0.4 0.8 8.4 0.4 2.3 81.4 6.3 0.4 0.2 1.6 8.4 100.0 2 100.0 511 �Table C-1. Distribution of Colorado recoveries (expressed as a percent for mallards banded during winter within the Sterling-Julesburg Colorado from 1963-83. Indirect recoveries Direct recoveries Subadult Adult Adult Subadult Male Female Male Female Total Male Female Male Female Total All birds Sterling-Julesburg Ft. Morgan-Sterling Greeley-Ft. Morgan South Platte River 60.8 20.3 5.4 86.5 75.0 18.8 30.8 23.1 23.1 76.9 55.2 21.7 6.3 83.2 56.3 20.2 9.8 86.3 71.1 18.4 · 45.0 25.0 5.0 75.0 89.5 35.1 26.4 13.5 75.0 40.0 20.0 16.7 76.7 48.6 22.3 10.8 81.7 50.4 22.1 9.6 82.1 Northern Foothills Southern Foothills Foothills 1.4 6.8 8.1 · · 2.5 17.5 20.0 7.7 7.7 15.4 2.1 9.1 11.2 4.4 6.0 10.4 10.5 10.5 · 4.7 16.2 20.9 3.3 16.7 20.0 4.0 11.0 15.0 3.5 10.5 14.0 Bonny Reservoir 1.4 · · 0.7 1.1 3.3 1.5 1.3 · · 6.2 · · · · · . 0.5 · · · · ·· 2.0 0.3 1.4 · · · · ·· · · · 0.3 0.2 0.2 0.2 0.2 0.7 · 0.7 0.7 1.4 0.5 0.3 0.8 0.7 0.4 1.1 · 0.5 0.3 0.8 0.4 0.4 0.7 100.0 399 100.0 542 Unit Unit Unit Uni t Southeast 8 10 11 12 Colorado San Luis Valley Middle Park Mountain Parks Gunnison River Colorado River Western Colorado Total (percent) Total recovered · 1.4 2.7 93.7 · · 6.2 2.5 · ·· · · 100.0 74 100.0 16 100.0 40 1.4 1.4· 2.5 2.5 2.5 management unit, · 7.7 7.7 · 100.0 13 0.7 0.7 0.7 2.1 · 0.5· 1.4 0.7 2.1 0.5 0.5 . 1.1 · 0.7 0.7 · 1.1 · · · · 100.0 143 100.0 183 100.0 38 · · · · · 0.7 0.7 100.0 148 . 100.0 30 N o w �Table C-2. Distribution of Colorado recoveries (expressed as a percent for mallards banded during winter within the Ft. Morgan·Sterling management unit, Colorado from 1963-84. N 0 ~ Direct recoveries Adult Indirect recoveries Subadult Adult Subadult All birds Male Female Male Female Total Male Female Male Female Sterling·Julesburg Ft. Morgan·Sterling Greeley·Ft. Morgan South Platte River 12.8 57.4 12.8 83.0 10.0 60.0 16.7 86.7 10.1 36.2 20.3 66.7 16.7 50.0 25.0 91.7 11.7 50.2 16.6 78.5 8.9 51.8 20.0 80.7 9.8 54.9 23.5 88.2 10.1 30.3 23.9 64.3 5.8 38.5 19.2 63.5 9.1 43.0 21.7 73.8 . 9.8 44.8 20.4 75.0 Northern Foothills Southern Foothills Foothills 1.1 11.7 12.8 3.3 6.7 10.0 11.6 17.4 29.0 8.3 5.4 12.2 17.6 2.6 13.1 15.7 3.9 5.9 9.8 6.3 24.8 31.1 15.4 17.3 32.7 5.1 17.2 22.3 5.2 16.0 21.2 1.1 · 2.9 1.5 1.3 · 0.8 1.9 1.1 1.2 0.5 0.7 0.7 ·· 0.4 0.5 0.5 0.2 0.8 1.9 0.5 0.4 0.2 0.6 1.6 0.4 0.4 0.5 0.5 0.7 0.7 0.4 0.8 1.3 0.2 0.3 0.5 0.1 0.2 0.4 100.0 646 100.0 851 Bonny Reservoir Unit Uni t Uni t Unit Southeast 8 10 12 13 Colorado San luis Valley Mountain Parks .. 1.1 · · · 3.3 2.1 2.1 1.1 Gunnison River Colorado River Western Colorado Total (percent) Total recovered 3.3 100.0 94 · · · 8.3 · ·· 0.5 · · · · 1.0 · 0.3 1.6 · 1.4 1.4 ·· 1.5 1.5 0.7 0.7 · · · · · · ·· 100.0 30 100.0 69 100.0 12 100.0 205 . 100.0 305 · 2.0 2.0 · · 100.0 51 . 1.9 0.4 1.3 2.1 1.9 100.0 238 100.0 52 Total �Table C-3. Distribution of Colorado recoveries (expressed as a percent for mallards banded during winter within the Greeley-Ft. Morgan management unit, Colorado from 1963-83. Direct recoveries Indirect recoveries Subadult Adult Adult Subadult -Male Female Male Female Total Male Female Male Female Total All birds Sterling-Julesburg Ft. Morgan Sterling Greeley-Ft. Morgan South Platte River 1.0 8.6 60.0 69.5 6.9 17.2 41.4 65.5 7.5 15.1 34.0 56.6 3.3 13.3 46.7 63.3 3.7 12.0 49.3 65.0 4.1 13.6 48.6 66.4 4.0 12.0 36.0 52.0 2.4 10.9 38.9 52.1 6.5 37.0 43.5 · 3.0 11.8 42.5 57.3 3.2 11.8 44.5 59.5 Northern Foothills Southern Foothills Foothills 5.7 22.9 28.6 6.9 20.7 27.6 5.7 34.0 39.6 10.0 23.3 33.3 6.5 25.3 31.8 8.2 22.7 30.9 18.0 28.0 46.0 12.3 30.8 43.1 21.7 30.4 52.2 12.0 27.1 39.1 10.3 26.6 37.0 1.0 3.4 1.9 1.4 0.9 · 0.9 2.2 0.9 1.1 · · · · · 3.4· · ·· 2.0 · 0.9 0.5 0.5 1.9 2.2 3.4 0.5 0.5 0.5 1.4 · 2.2· 0.8 0.6 0.4 1.7 0.5 0.4 0.4 1.3 · ·· . . ·· 0.4 Bonny Reservoir Unit Unit Unit Southeast 8 10 13 Colorado North ParI<: San Luis Valley Middle ParI<: Mountain Parl<:s Gunnison River Colorado River Ya~a River Western Colorado Total (percent) Total recovered 1.0 · ·· · · 1.9 · · · 0.5 0.5 0.5 0.5 0.5 1.4 0.5 · · 2.0 · · · · · · · · · · · · · · · · · 100.0 105 100.0 29 100.0 53 100.0 30 100.0 217 100.0 220 100.0 50 1.0 1.9 · 3.3 3.3 ·· 0.5 ·· · 0.5 0.5 0.5 0.5 0.5 1.4 100.0 211 · ·· · 100.0 46 0.4 0.1 0.4 0.1 0.7 0.2 0.2 0.2 0.6 0.1 0.1 0.1 0.4 100.0 527 100.0 744 N o VI �Table C-4_ Distribution of Colorado recoveries (expressed as a percent) for mallards banded during winter within the Northern Foothills management unit, Colorado from 1963-84. N 0 (J\ Indirect recoveries Direct recoveries Adult Subadult Male Female Male Female Sterling-Julesburg Ft. Morgan-Sterling Greeley-Ft. Morgan South Platte River 1.9 4.8 8.7 15.4 6.7· · 3.3· 6.7 1.4 8.5 7.0 16.9 Northern Foothills Southern Foothills Foothills 44.2 38.5 82.7 64.4 20.0 84.4 32.4 47.9 80.3 Bonny Reservoir Unit Unit Uni t Uni t Southeast 8 10 12 13 Colorado North Park South Park San Luis Valley Mountain Parks Southwest Gunnison River Colorado River Yafl1'8River Western Colorado Total (percent) Total recovered · 1.0 1.0 · 1.0 1.0 · · · 2.2· 2.2 2.2 · · 2.2 · · · ·· 2.2 2.2 4.4 100.0 104 100.0 45 · · ·· · · · · · 100.0 71 -- --- Male Female Male Female Male 50.0 1.6 4.4 7.1 13.1 0.9 1.5 6.3 8.7 1.4 7.0 8.5 · 0.8 5.9 17.2 23.9 2.1 8.3 10.4 44.8 38.5 83.3 52.6 36.6 89.2 56.3 31.0 87.3 28.6 44.5 73.1 50.0 35.4 85.4 0.4 2.1 0.8 0.4 · · · 50.0 43.3 93.3 50.0 50.0 3.3 3.3 · · · · · · · · · · · · · · 1.2 1.2 0.4 0.4 0.8 1.6 0.3 · 0.3 0.3 0.3 0.9 · 0.6· · · ·· · 0.4 0.8 0.3 100.0 2 100.0 252 100.0 333 · 100.0 30 Unknown Total 50.0 · · · Subadult Male 3.3 · 1.4 1.4 2.8 Adult Unknown · 0.4· 2.8 1.4 4.2 . . 1.3 · 0.6 · 0.3 · · · 100.0 71 0.4 0.4 0.4 · · ·· 2.1· 2.1· Total All birds 0.7 3.0 10.2 13.9 0.9 3.4 9.4 13.7 44.6 38.6 83.2 44.7 38.6 83.2 0.4 0.3 · · 0.6 0.3 0.1 0.3 1.3 0.4 0.2 0.1 0.5 1.3 · · 0.1 0.3 0.4 0.1 0.2 0.4 0.7 14.3 0.3 0.3 0.1 · · · 57.1 28.6 85.7 1.3 · 14.3 0.7 0.2 0.2 0.2 0.1 0.7 100.0 238 100.0 48 100.0 7 100.0 697 100.0 949 · · · · �Table C-5_ Distribution of Colorado recoveries (expressed as Colorado from 1963-84. 8 percent for mallards banded during winter within the Southern Foothills management unit, Direct recoveries Adult Indirect recoveries Subadult Adult Subadult Unknown Total All birds · ·· 1.5 3.5 11.3 16.4 1.4 3.0 10.9 15.3 · 19.0 62.2 81.2 17.5 63.6 81.1 0.4 0.4 0.1 0.1 0.1 0.2 0.3 0.3 0.4 1.1 Male Female Male Female Total Male Female Male Female Sterling-Julesburg Ft. Morgan-Sterling Greeley-Ft. Morgan South Platte River 1.2 3.0 10.9 15.2 · 17.0 17.0 · 1.4 1.4 7.9 10.8 2.0 2.0 5.9 9.8 1.2 2.0 10.0 13.2 1.6 3.2 9.3 14.1 1.5 3.1 4.6 1.8 4.2 14.1 20.1 1.4 4.3 18.8 24.6 Northern Foothills Southern Foothills Foothills 13.3 68.5 81.8 6.4 72.3 78.7 15.8 66.2 82.0 21.6 54.9 76.5 14.4 66.4 80.8 22.3 61.7 84.0 16.9 73.8 90.8 15.5 62.5 78.1 17.4 52.2 69.6 100.0 100.0 · · 0.7 2.0 0.5 0.5 · 0.4 · 2.1 · · 0.4 1.4 1.4 2.2 0.2 0.5 0.5 1.2 2.5 · · 2.1 · · 2.0 2.0· · · · 2.2· 0.4 2.9 · 2.1· 1.4 · · 3.9· 1.4 3.9 0.5 0.2 0.5 1.2 · 0.8· 2.0 3.9 5.9 . 0.3 1.4 1.4 2.9 0.7 1.0 1.7 0.3 0.5 3.1 3.1 0.7 2.9 · 100.0 139 100.0 51 100.0 402 100.0 376 100.0 65 100.0 283 100.0 69 100.0 1 Bonny Reservoir Unit Unit Unit Uni t Southeast 8 10 12 13 Colorado 0.6 0.6 0.6 1.2 3.0 South Park San luis Valley Middle Park Mountain Parks · · Southwest Gunnison River Colorado River Western Colorado · · · · Total (percent) Total recovered · 100.0 165 2.1 · ·· 100.0 47 · · · · · · · 0.8 · 0.4 1.5 · 0.4· · 0.7 1.5 · ·· · · 2.9 Male · · · 0.4 · · · · · 0.1 0.5 0.6 0.3 0.4 0.2 0.8 0.1 0.3 0.6 1.0 0.1 0.4 0.8 1.3 100.0 794 100.0 1196 . N o -...J �Table C-6. Distribution of Colorado recoveries (expressed as a percent) for mallards banded during winter at Bonny Reservoir, Colorado from 1983-86. N 0 co Direct recoveries Adult Subadult Indirect recoveries Adult Unknown Subadul t Unknown --Male · Female Male Female · 4.3 8.7 · · Sterling-Julesburg Ft. Morgan Sterling Greeley-Ft. Morgan South Platte River 7.1 2.4 9.5 5.9 5.9 11.8 Northern Foothills Southern Foothills Foothills · 5.9 3.6 3.6 Bonny Reservoir Uni t Uni t Uni t Uni t Southeast 10 12 13 14 Colorado San Lui s Valley Mountain Parks Gunnison River Colorado River Western Colorado Total (percent) Total recovered 85.7 5.9· 64.7 · · 17.6 1.2 1.2 · · · 13.0 · 16.7 16.7 · 34.8 34.8 16.7 16.7 47.8 41.7 · · 4.3· 4.3 8.3 Male Total Male Female Hale Female 0.7 6.6 3.6 10.9 4.3 3.8 5.2 13.3 3.6 13.6 3.6 7.7 7.7 7.7 23.1 0.7 9.5 10.2 1.0 2.9 3.8 3.6 7.1 10.7 4.8 11.5 16.3 13.6 73.0 80.5 78.6 50.0 68.2 ·· 2.2 1.5 3.6 . 0.5 0.5 1.0 3.6 · 2.9 3.8 1.9 0.7 4.4 1.9 7.1 8.7 · 1.0 1.0 0.7 0.7 0.5 100.0 137 100.0 210 · ·· · · · · 100.0 · · · · · 8.3 8.3 ·· · · · · 8.3 8.3 ·· · · ·· 100.0 84 100.0 17 100.0 23 100.0 12 100.0 1 · · 17.6 8.3 · --- · 0.7 0.7 . . . 0.5 · 4.5 18.2 13.6· Total All birds · · 5.7 4.3 6.2 16.3 4.3 4.9 5.5 14.8 · ·· 3.0 5.4 8.4 2.4 6.5 8.9 70.5 71.1 1.4 1.4 1.4 · 4.1 1.6 1.4 1.0 0.2 4.2 Male 60.0 60.0 40.0 · ·· · · · · · 0.3 0.3 0.4 0.4 1.0 · · · ·· · 0.5 · . 0.5 0.4 0.2 0.6 100.0 28 100.0 104 100.0 22 100.0 5 100.0 369 100.0 506 · · . 1.0 · . . �Table C-7. Distribution of Colorado recoveries (expressed as a percent) for mallards banded during winter in Southeast Colorado from 1963-83. Indirect recoveries Direct recoveries Adult Subadult Adult Subadul t Male Female Male Female Total Male Female Male Female Total All birds Sterling-Julesburg Ft. Morgan-Sterling Greeley-Ft. Morgan South Platte River 1.6 6.3 7.9 15.9 3.3 3.3 0.8 5.1 4.2 10.2 3.0 7.5 4.0 14.6 6.2 12.5 3.6 5.4 3.6 12.6 · · ··· 6.2 7.1 5.3 5.3 10.5 3.3 6.1 4.2 13.6 2.7 5.8 4.2 12.7 Northern Foothills Southern Foothills Foothills 3.2 1.6 4.8 7.1 7.1· 23.3 23.3 9.1 9.1 · 2.5 7.6 10.2 2.5 8.5 11.1 12.5 12.5 · 6.3 17.1 23.4 · · 3.3 11.1 14.4 3.1 10.2 13.4 Bonny Reservoir 1.6 · 6.7 9.1 3.4 2.0 3.1 2.7 5.3 2.5 2.7 0.8 2.5 · 0.9 5.3 1.9 1.7 13.6 5.9 24.6 22.9 0.8 68.6 10.6 13.1 18.1 25.1 15.6 9.4 25.0 18.8 10.5 10.5 26.3 26.3 69.3 · 68.7 · 10.8 0.9 18.0 22.5 0.9 54.1 11.1 8.9 19.1 23.8 0.3 65.1 11.7 8.1 20.5 23.6 0.4 66.0 0.5 2.5 3.1 · 3.1· 0.9 0.9 0.9 2.7 0.6 2.2 0.3 3.0 1.0 2.1 0.6 3.8 0.6 0.8 Unit 8 Uni t Uni t Unit Unit Uni t Southeast 10 11 12 13 14 Colorado South Park San Luis Valley Middle Park Mountain Parks Gunnison River Colorado River Yampa River Western Colorado Total (percent) Total recovered 7.1 · · · 1.6 12.7 6.3 31.7 22.2 1.6 76.2 21.4 21.4 13.3 6.7 16.7 23.3 71.4 60.0 · 1.6· 7.1 7.1 1.6 14.3 28.6· ·· · · 100.0 63 100.0 14 · · 3.3 3.3 6.7 · · 9.1 9.1 · 45.5· 27.3 18.2 · 18.2· 2.5 1.7 1.7 5.9 9.1 0.8 · 9.1 18.2 100.0 30 100.0 11 3.0 1.7 · · 100.0 118 100.0 199 . 0.8 · · · 78.9 · 5.3 5.3 1.8 2.7 · · 4.5 · 1.4 0.6 0.6 0.2 1.5 100.0 32 100.0 111 100.0 19 100.0 361 100.0 479 . Table C-8. Distribution of Colorado recoveries (expressed as a percent for mallards banded during winter within the Gunnison River management unit, Colorado from 1973-82. N 0 I.D �Table C-8. Distribution of Colorado recoveries (expressed as a percent for mallards banded during winter within the Gunnison River management unit, Colorado from 1973-82. N I-' 0 Indirect recoveries Direct recoveries Subadult Adult Male Sterling-Julesburg Ft. Morgan-Sterling Greeley-Ft. Morgan South Platte River · 2.4 Northern Foothills Southern Foothills Footh ills 2.4 Bonny Reservoir 2.4 Unit Unit Unit Southeast 8 13 14 Colorado San Luis Valley Mountain Parks Southwest Gunnison River Colorado River Ya~a River Western Colorado Total (percent) Total recovered · · · 2.4 2.4 · Female Male · ·· 1.6 Female · · · · 1.6· · ·· 1.6 3.2 4.8 · · 1.6· · · · · · · 1.6 · · · 92.9 · 4.3 73.9 17.4 4.3 100.0 100.0 42 100.0 23 76.2 16.7 Adult Total 0.7 · 1.2 1.2 · · · 1.3 1.3 2.6 2.4 2.4 · 0.7 · · · · 0.7· · 0.7 0.7 · 4.2 4.2 8.0 80.0 12.0 1.2 78.8 11.8 79.2 12.5 1.0 66.3 26.5 91.8 · 91.7 · 93.9 100.0 85 100.0 24 100.0 98 0.7 100.0 · 100.0 63 100.0 25 100.0 153 · Male · 92.1 · Female · 0.7 2.0 71.2 20.9 0.7 94.8 63.5 28.6 Male Subadult ·· Female 2.0 2.0 2.4 1.2 1.6 · 1.0 2.0 3.1 7.1 2.4 9.5 1.6 2.4 4.0 1.5 2.0 3.5 2.4 · · · 0.8 0.7 1.2 1.2 · · · · · · · 2.4· · 2.4 0.4 0.4 . 0.4 1.2 0.2 0.5 0.2 1.0 0.8 0.8 0.7 0.7 69.0 16.7 0.8 72.3 18.5 85.7 · 91.6 1.2 71.9 19.4 0.2 92.8 100.0 42 100.0 249 100.0 402 · 2.4 · 4.2 4.2 · · 1.0 1.0 0.4 All birds 0.2 0.2 0.7 1.2 · 2.4 Total . �Table C-9. Distribution of Colorado recoveries (expressed as a percent for mallards banded during winter within the Colorado River management unit, Colorado from 1973-82. Direct recoveries Adult Indirect recoveries Subadult Adult Subadult Unknown --Male Sterling-Julesburg Ft. Morgan Sterling Greeley-Ft. Morgan South Platte River 1.7 Northern Foothills Southern Foothills Foothills 1.7 1.7 1.7 Unit 8 Uni t 13 Southeast Colorado South Park San Luis Valley Middle Park Mountain Parks Southwest Gunnison River Colorado River Yampa River Western Colorado Total (percent) Total recovered Female · · · · · · · · · · · ·· · · · · 29.2· 1.7 10.2 84.7 70.8 96.6 100.0 59 Male · · · · · 4.1 4.1 Female · ·· · 7.1· 7.1 2.0 2.0 4.1 · · 2.0· · 2.0 100.0 · 2.0 16.3 69.4 2.0 89.8 100.0 24 100.0 49 · · 3.6 3.6 Total Male Female Male · 0.8 0.6 · 0.6 · 2.9 0.8 1.7 3.1 3.1 1.7 1.7 0.6 0.6 1.3 1.7 1.7 · 0.6 0.6 1.3 3.6 · 0.8 0.8 · · · 0.8 2.4 3.1 2.9 · 0.8 0.8 · 3.6 · · · · Total All birds · · · 0.3 0.9 0.6 1.8 0.2 0.8 0.4 1.4 · 0.3 1.8 2.1 0.2 2.2 2.4 Male 50.0 50.0 ·· · ·· . 0.9 0.9 0.2 0.8 1.0 0.6 1.5 0.3 2.4 0.4 1.2 0.4 2.0 1.0 15.1 76.1 1.0 93.2 100.0 498 · · 0.8 3.9 · 0.8 · 4.7 1.8 1.8 14.2 80.0 · 2.9 14.7 79.4 1.8 18.2 70.9 3.6 94.5 50.0 · 50.0· 0.9 15.4 75.4 1.2 92.9 100.0 55 100.0 2 100.0 338 0.8 · 89.3 1.3 14.4 77.5 0.6 93.7 94.2 · 97.1 0.8 15.7 72.4 1.6 90.6 100.0 28 100.0 160 100.0 120 100.0 34 100.0 127 7.1 82.1 Female · · · N •..... •..... ��Colorado Division Wildlife Research September 1991 of Wildlife Report JOB PROGRESS REPORT State of __~C~o~l~o~r~a~d~o~ Project _ Avian Research W-152-R-4 Work Plan 10 Job Title: : Job Cooperative Management Programs 01 April 1990 through 31 March 1991 Author: R. Szymczak Personnel: Game Birds _1_ Period Covered: Michael - Migratory James K. Ringelman Wildlife and Michael R. Szymczak, Colorado Division of ABSTRACT The final draft of the San Luis Valley Waterbird Plan was completed and submitted for administrative approval. Recommendations concerning waterfowl and wetland issues were made to committees formulating the North Park waterfowl plan and San Luis Valley Water Plan. Recommendations for wetland habitat improvements on present holdings or proposed acquisitions were provided for Russell Lakes, South Republican and Riggs SWA's and the Ham property and Pole Mountain Reservoir. Presentations on various aspects of waterfowl ecology were given at training and educational schools, workshops, and short courses. Waterfowl counts designed to help identify population limiting factors were conducted on ducks and/or geese in portions of North Park and South Park. An extensive study of duck production was conducted in montane habitat study areas on the Routt National Forest. Responsibilities as Colorado's representative on Pacific Flyway Study Committees and Council were fulfilled. ��215 Cooperative Migratory Bird Management Programs Michael R. Szymczak James K. Ringelman In 1988, the Colorado Division of Wildlife (CDOW) created the Migratory Game Bird Program Unit (MBPU) within the Terrestrial Wildlife Section. This administrative change combined all individuals having statewide responsibilities for research and management of migratory game birds. Members of the MBPU work in concert to improve migratory bird management in Colorado, This job was created to allow team members to participate in these management programs. P. N. OBJECTIVES 1. Participate in developing and implementing habitat-based waterfowl management plans on a statewide, habitat region, and project basis. 2. Advise state and federal land managers on beneficial habitat acquisitions and/or developments and provide expertise in preparation of development and/or management plans. Advise private land managers in developing habitat management plans and assessing impacts on waterbird populations. 3. Present information on the principles of waterfowl management to workshop attendees, educational classes, and conservation organizations. 4. Participate in migratory bird management meetings at the state and flyway levels. 5. Cooperate in developing surveys and techniques that will assess the impact of migratory bird management programs. SEGMENT OBJECTIVES 1. In conjunction with the statewide waterfowl management plan, begin work on waterfowl habitat region plans. 2. Provide biological expertise for wetland development programs on the Brush, Russell Lakes, South Republican State Wildlife Areas, Hebron Ponds and Walden Reservoir (BLM-CDOW), Routt National Forest (U.S. Forest Service - TAKING WING), and other areas when requested. 3. Prepare and present informational programs on migratory bird management when requested. 4. Compile appropriate population status information and represent Colorado at Pacific Flyway Technical Committee and Council meetings. Attend migratory bird management program meetings in Colorado when requested. 5. Provide methodology for wetland habitat and migratory bird population surveys when requested. �216 RESULTS Waterfowl Management Plans The San Luis Valley Waterbird Plan was completed by a multi-agency plan committee and awaits submission to CDOW administrators. Migratory Game Bird personnel compiled sections of the plan dealing with historical levels of game bird resources and formulated objectives, issues, and strategies dealing with game bird populations and their habitats. The entire plan was reviewed a number of times by project personnel. The current draft of the CDOW Water Management Plan for the San Luis Valley was reviewed. Input on current years water allocation was provided in a meeting of plan committee members. Current and future management plans for the Monte Vista National Wildlife Refuge were discussed with refuge personnel. Current on-the-ground changes were visited and unofficial comments were made to refuge personnel on the direction of current management. Some preliminary information on waterfowl populations was forwarded to CDOW personnel responsible for developing a Waterfowl Management Plan for North Park. In conjunction with the North Park Plan, project personnel participated on a multi-agency committee formulating a proposal for a major expansion of the Arapaho NWR. The proposal encompasses the purchase of MacFarlane and Pole Mountain reservoirs and a major portion of the Soap Creek Ranch. Completion of planned purchases would result in a reliable water source for the Hebron Sloughs development. Wetland Developments and Acquisitions Potential sites for wetland developments and existing wetlands were visited on the Russell Lakes SWA in the San Luis Valley, the South Republican SWA at Bonny Reservoir and the Rigg SWA near Rocky Ford. Recommendations for wetland construction, water management, and management of existing wetlands were given to CDOW management personnel. Possible solutions for impending water availability problems at Eads Lakes were discussed with CDOW Southeast Regional personnel. Proposed areas for wetland enhancement in the Denver Metropolitan area were toured and suggestions made for development to CDOW Central Region personnel. Waterfowl count information for Pole Mountain Reservoir in North Park was compiled and forwarded to the Northeast Region in support of acquisition of the Reservoir. Wetlands on the Ham property located along the lower Arkansas River in Southeast Colorado were evaluated for CDOW acquisition. Project personnel, as members of the multi-agency Waterfowl Habitat Project Review Committee, reviewed and rated wetland enhancement and acquisition proposals from land management agencies for funding with Colorado State Duck Stamp monies. Ten enhancement proposals were recommended for funding and forwarded for CDOW Terrestrial staff and appropriate Regional approval. Informational Programs Formal presentations on waterfowl recruitment in montane habitats were presented to U.S. Forest Service personnel in Steamboat Springs, the Colorado Natural Areas Committee, and the national meeting of the Society of Wetland Scientists. Presentations on waterfowl ecology and management were made to CDOW District Wildlife Management Trainees, the Platte River Symposium, the Wildlife Management Shortcourse and Wildlife Biology Workshop at Colorado State University and the Avian Management course at Colorado State University. Presentations on �217 wetland development for waterfowl and duck identification were given at the Southeast Region training school. cnaw Waterfowl Technical Committee and Council Meetings The Rocky Mountain Greater Sandhill Crane and Rocky Mountain Canada Goose Management Plans were reviewed and revisions proposed by respective population committee members, including Colorado, at a special meeting in January 1991. Crane plan changes were forwarded to the Pacific Flyway Council and approved in March 1991. All RMP goose plan changes have yet to be finalized. Colorado was represented at the July 1990 and March 1991 Pacific Flyway Study Committee meetings by project personnel. Waterfowl population status was reviewed in July and hunting season recommendations forwarded to the U. S. Fish and Wildlife Service's Regulation Committee. Populations of specific interest to Colorado whose status was reviewed in July were (1) breeding and wintering mallards inhabiting the Pacific Flyway portion of Colorado and (2) the Rocky Mountain Canada goose population. General information on Pacific Flyway migratory game bird populations was exchanged by committee members in March. Regulatory recommendations made to the Pacific Flyway Council included hunting season regulations for Rocky Mountain Greater Sandhill Cranes and Four-corners Band-tailed Pigeon populations. Population Survey Methodology Spring duck count surveys were conducted on Spinney Mountain SWA in South Park and in kettle lake-beaver pond habitat immediately south of Big Creek Lake in North Park. Spinney Mountain counts were designed to obtain pre-wetland development baseline information on breeding pairs on the SWA. Counts in North Park were designed as a test of a predictor equation for estimating the number of duck breeding pairs in montane habitats using aerial photographs, with pond size the critical variable. The equation was developed using information obtained during a cooperative study of waterfowl recruitment in montane habitats (Langley et al. 1990). An extensive, cooperative study of nesting waterfowl on forested study sites immediately west of North Park (Routt National Forest) continued in 1990. New study sites were selected in 1990 with the primary intent of establishing protocol for future waterfowl research and management on Forest Service lands. Results of this cooperative study are presented as an appendix to this report. Surveys of nesting and brood rearing Canada geese on Walden and MacFarlane reservoirs in North Park during spring 1990 documented poor productivity at both sites. Goose nests visited, marked, and mapped in early May just prior to hatch, and revisited after all had hatched showed good hatchability. Periodic brood counts made post-hatch indicated gosling mortality probably occurred shortly after hatch. A detailed report was submitted to Northeast Regional and Bureau of Land Management personnel. DISCUSSION Project personnel proved to be a useful resource in planning and evaluating waterfowl management and habitat enhancement programs in Colorado and educating land management agency personnel about the habitat requirements of waterfowl. We experienced increased involvement in long-range planning for waterfowl on specific areas. We anticipate that with increased emphasis on habitat enhancement in Colorado as outlined in the statewide Waterfowl Management Plan that our services will be more in demand. �218 Continued participation on Flyway committees ensures that Colorado will remain informed on migratory bird matters and have input in migratory bird hunting regulations. Prepared by: Michael R. Szymczak Wildlife Researcher C �219 APPENDIX A Report on the cooperative investigation of waterfowl recruitment habitats in the Routt National Forest, Colorado in montane Field Personnel R. Langley, Colorado Division of Wildlife M. Wotawa, Colorado Division of Wildlife J. Ringelman, Colorado Division of Wildlife Cooperators C. Neelan, u.s. Forest Service, Steamboat Springs S. Kozlowski, U.S. Forest Service, Walden G. Hetzel, U.S. Forest Service, Denver L. Mullen, U.S. Forest Service, Denver S. Porter, Colorado Division of Wildlife, Walden K. Snyder, Colorado Division of Wildlife, Walden M. Szymczak, Colorado Division of Wildlife, Ft. Collins R. Hopper, Colorado Division of Wildlife, Ft. Collins ��221 WATERFOWL ABUNDANCE AND PRODUCTION ON THE ROUTT NATIONAL FOREST, COLORADO, 1990 James K. Ringelman, Mark A. Wotawa, and Richard S. Langley Colorado Division of Wildlife, Ft. Collins, CO 80526 Abstract: We enumerated duck breeding pairs and broods, derived indices of nesting success, and documented duckling survival in 6 montane wetland communities in the Routt National Forest near the western edge of North Park, Colorado. Of the estimated 92 resident pairs, the majority were mallards (51%) and ring-necked ducks (21%), followed by bufflehead (13%) and green-winged teal (10%). Overall pair density averaged 11.2 patrs/krn". Pair densities ranged from 6.0 pairs/krrr' at Newcomb Creek to 25.7 palrs/krn" at Upper Beaver Creek. Newcomb Creek and Lone Pine\Bear Creeks had fewer than 10.0 pairs/krn", whereas Colorado Creek, Livingston Park, and Upper Beaver Creek had > 20.0 palrs/krrr'. Ratios of lone males to pairs indicated that nest success was relatively high (> 50%) for all areas and species. A minimum of 56 broods were produced, but duckling survival was low for ring-necked ducks and bufflehead. Consequently, the 99 ducklings that were observed on the areas near the time of fledging was far short of the potential recruitment of 230 birds. Compared with the 1989 Routt Forest study area, the 6 areas surveyed in 1990 had higher pair densities on a unit area basis (11.2 versus 6.1 km2) but similar densities of pairs per pond (0.30 versus 0.32). Nest success appeared high during both years. Overall estimates of minimum brood survival were also similar (54% in 1989 versus 48% in 1990). However, high duckling mortality rates among ring-necked ducks and buffleheads limited recruitment both years. Recent declines in North American duck populations have prompted coordinated action by state and federal natural resource agencies. Under the umbrella of the North American Waterfowl Management Plan, the U.S. Forest Service (USFS) has initiated a 5-year, $18 million program to survey and improve waterfowl habitat on USFS lands. This program, called "Taking Wing", addresses the needs of breeding waterfowl through habitat preservation and development. Based on USFS landholdings in 1988, forested montane habitat covers at least 56,000 km2 in the central Rocky Mountain region. Although comparable in size to the United States portion of the prairie pothole region (280,000 km2), Rocky Mountain montane waterfowl habitats have attributes that set them apart from their grassland counterparts. First, montane wetland communities are relatively intact compared to the widespread wetland degradation typical of the northern Great Plains. Second, except for relatively small, confined, impacts such as mining operations, roads, and ski areas, adjacent upland plant communities still possess a compliment of native plant species despite some grazing and timber harvest. Third, snowfall provides a reliable source of spring water, creating waterfowl breeding habitat that is relatively stable compared to prairie breeding grounds. Such stability may be particularly important during times of widespread drought on the prairies, which has occurred in recent years. Habitat development techniques proposed for the ''Taking Wing" program include (1) wetland vegetation management and construction of new wetlands, (2) upland nesting cover enhancement and creation of secure nesting habitat in the form of islands, nest structures, or predator-proof enclosures, and (3) provision of additional permanent water areas and establishment of animal and vegetative foods. These techniques, which have been developed and tested primarily in prairie habitat, may attract and hold breeding pairs, increase nest success, and enhance brood survival, respectively. Unfortunately, little is known about which of these factors may limit waterfowl production in Rocky Mountain breeding habitat. Applying any management technique without first identifying the limiting factor is a waste of valuable resources. In 1989, 4 wetland complexes in Routt National Forest were investigated to determine which phase of the waterfowl reproductive life cycle inhibited production (Ringelman et aI., 1989). Their �222 results indicate that low brood survival was the major cause of low duck recruitment. In 1990, we used the same survey techniques to determine inhibiting factors on 6 new wetland complexes within Routt National Forest. Our specific objectives were to (1) determine the species composition, abundance, and habitat use by waterfowl breeding pairs in 6 wetland communities on Routt National Forest, (2) use the ratio of lone males to pairs as an indication of nesting chronology and nest loss/renestlnq activity, (3) measure duckling survival rates, hatch to fledging, and habitat use by brood-rearing hens, and (4) identify management options to improve waterfowl recruitment. STUDY AREAS We surveyed 6 wetland communities within Routt National Forest along the western edge of a dry intermountain area known as North Park, Colorado (Figs. 1-7). Number, density, origin, and elevation of ponds varied for each study unit (Table 1). Other general characteristics unique to each study unit are described below. Dominant forest vegetation consisted of lodgepole pine (Pinus contorta), Engelmann spruce (~ engelmannii), subalpine fir (~ lasiocarpa), and quaking aspen (Populus tremuloides). Riparian zones were dominated by willows (Salix spp.), with smaller amounts of mountain alder (~~). Common aquatic vegetation included cowlily (Nuphar polysepalum), northern mannagrass (Glyceria borealis), grassleaf pondweed (Potamogeton gramineus), fineleaf pondweed (.E. filiformis), spiked watermilfoil (Myriophyllum spicatum), and sedges (~ vescaria and Q. utriculata). Predators which could prey upon waterfowl and their nests in the area include coyote (~ latrans), badger (Taxidea ~), mink (Mustela ~), pine marten (Martes americana), striped skunk (Mephitis mephitis) and northern goshawks (Accipiter gentilis). Newcomb Creek The largest, deepest ponds in this unit (Teal Lake, Tiago Lake, and Burns Reservoir) were accessible by a maintained road and were used extensively for recreational purposes. Camping in developed and undeveloped sites, fishing, and use of small boats at these lakes began in early June (Memorial Day), increased substantially by early JUly (Independence Day), and continued throughout the summer. Other ponds had various degrees of accessibility (main road, logging roads, and no roads) but were not used for recreational purposes. Clearcuts of pine (north of Newcomb Creek) and aspen (south of Newcomb Creek) were common and bordered several ponds. Runoff from snowmelt and the low summer precipitation were the only source of water for ponds in this unit. Thus, ponds were shallow, water level declined during the summer, and aquatic vegetation was prominent by late summer. Colorado Creek This unit is composed of two different segments, east and west. The western ponds were higher in elevation and were ice-free at least 2 weeks later than the eastern ponds. A high percentage of snow cover persisted in the western segment until early June. The lower elevation, eastern segment had been heavily clearcut adjacent to most ponds, and revegetation of both forest and herbaceous vegetation was minimal. Clearcuts skirted the western segment and some of the ponds along the perimeter, but the segment as a whole was uncut. Large amounts of forest debris from blowdown and cut trees that weren't removed was common in both segments. Cattle grazing began in late August in both segments, but was most pronounced in the clearcut areas of the eastern segment. Other than the main road, use of logging roads by recreationists was rare during the summer. As with Newcomb Creek, the water source of these ponds was limited to snowmelt and summer precipitation, resulting in decltninq water levels as the summer progressed. �223 Table 1. Compartative attributes of 6 study units located in Routt National Forest, Colorado, 1990. Size (km2) Study Unit Newcomb Creek Number of Wetlands Beaver Glacial Wetland Density Elevation (m) 5.16 3 47 9.7 2667 (west) 0.37 8 16 64.9 2804 (east) 0.54 5 28 89.2 2728 0.42 33 2 83.3 2658 (LPC) 0.35 27 4 88.6 2697 (BC) 0.35 26 0 74.3 2743 Upper Beaver Creek 0.35 35 13 137.1 2819 Lower Beaver Creek 0.68 55 1 82.3 2652 Total 8.22 192 111 36.9 Colorado Creek Livingston Park Lone Pine! Bear Creeks �224 . ," ~~~ .. u P f~ r t Lo •••.•cw- I , 41\11\& ~C\'IeC'" (.~c\< . " ,• \. .. - #., . . ", ' •..• ~". ·•·. .. , I I I ...•• •.. tt <I ~ , ... . " d C D .; " :z. ., . ( I ,, r . ~ I f~ ~U'( 5.) z ;,.Ioe\ \.u; \ At'ww~" I ~ :' . , , ., .". ---. -_ ....~ , •\ LC)\'\.( rih~ to 8'lcu.. ~ l.)e c\... C1"ee. \<.5 mo",,~ .'" rr, j . I ~ "' .••., o �:;.0 c-'l 0- o ~ 0 \) '0 ~c;; ~ c;?~ \j :r 225 a- 0 :r' (-L 0 . ~, II CJ �226 o -ee l- o - U 2t.e~ l-L �- ·2 -...J ,/ \ ....••. \ \ 227 \\ 1\ / \ I \ \ \ - \ \ \ \,. '\ "'laI �228 =z ~ v. -...._,/ 1 ~ cJ 6: ~ \ -.(. '-s C!) �,~ ~ ..1l ;r ~ r-~ ~ ~ :;:) <:» 0 :7" 0 ~ J ~ c1 ~ ':.. '::) C- C- cY ~ q~ ..•0 ;;r <, 229 �230 j f / / / / / rv <,.. J - a: u. �231 .MIBd 15 en "'C o o l.... 10 rn "t- O l.... CD .o E ::s Z 5 o 2 3 4 5 6 7 8 9 Week Figure 8. Week of hatch for duck broods found on Routt National Forest, Colorado, 1990. Week 1 corresponds to 28 May - 3 June. 10 11 �232 Livingston Park This unit is a beaver complex located in the back of an broad, open, steep sided boxed valley which opens to North Park proper in the east. In addition to snowmelt and surface ground water from precipitation, these ponds are fed by a small creek draining the mountains to the west. The bottom of the valley to the east of the main beaver complex was intermittently saturated with runoff and surface ground water, but contained few ponds. A portion of the Grizzly-Helena trail system bordered the main beaver complex, but the unit was generally isolated and undisturbed. Cattle were present on the unit in August, but numbers were unknown. Lone Pine/Bear Creeks This unit could also best be described as 2 segments separated by a large ridge: Lone Pine Creek to the south and Bear Creek to the north. Both segments had a constant source of runoff , water available to most ponds. The Lone Pine segment is a beaver complex that is accessible by a road along its north side. Recreationists in this segment were common but not necessarily abundant. It appears that beaver activity in Lone Pine is minimal. The complex is a series of ponds with a braided creek flowing through them, rather than a series of well maintained beaver ponds. Beaver dams are degenerating and willows are revegetating the complex. The Bear Creek segment consists of a series of small beaver complexes located in a narrow, forested, steep-sided valley. Access is limited to rough trails, resulting in little or no disturbance during the early summer months. Several of the ponds that were not fed directly by Bear Creek were dry. Upper and Lower Beaver Creeks The 2 units fed by Beaver Creek have similar wetland and upland habitats, and were considered separate units only because of a small separation between them and ease of sampling. Each is characterized by a large complex of stable beaver ponds, although the upper unit does contain some distinct, relatively large glacial ponds. Good roads border each unit, and logging roads and trails exist in the upper unit. The road along the north border of the lower unit is directly adjacent to ponds and is used consistently by logging trucks. Except for traffic on the main roads, disturbance to both units is probably minimal. Clearcuts are common near both units (especially the glacial ponds of the upper unit), but are not directly adjacent to the main beaver complexes of either unit. Cattle were present near the west border of the upper unit in mid August but did not enter the unit during this study. METHODS Abundance and Success of Nesting Pairs We surveyed Newcomb Creek, Colorado Creek, Livingston Park, and Lone Pine/Bear Creeks weekly from 16 May - 21 June, and Upper and Lower Beaver Creek weekly from 6-21 June. For each pond visited we recorded time, species present, sex, number of lone males, lone females, pairs, grouped birds, and whether birds were flushed. Ponds were approached silently to avoid flushing birds and duplicating counts. Surveys began during late morning (0800-1000) because incubating female otten take incubation breaks during early morning; surveys that consistently counted these females would result in lone male to pair ratios that were not indicative of nesting chronology or success. Changes in lone male to pair ratios were used as an index to nest success. We located nests opportunistically and recorded species, number of eggs, egg fertility, incubation stage, nest fate, and general habitat characteristics. �233 Brood Survival Surveys to locate and follow broods through fledging began on 25 June. Survey times included the first and last 4 hours of daylight (approximately 0500-0900 and 1700-2100). Only wetlands that were consistently used by breeding pairs were surveyed for broods. High priority ponds (those receiving highest pair use) were checked weekly, whereas lower priority ponds were checked intermittently. Lone Pine and Bear Creeks were dropped from brood surveys due to insignificant use by breeding pairs. We again approached ponds quietly, then remained until we observed broods or believed that the observation time was adequate to have detected broods had they been present (usually 15-90 minutes). For each brood, we recorded species, brood size, brood age (Gollop and Marshall, 1954), presence or absence of the hen, and pond number. Since broods were not marked, re-identification was based on records of previous locations, and brood size and age. We attempted to relocate all broods once a week. RESULTS Species Composition and Abundance We observed 8 species of ducks during the nesting season (Table 2). Estimated numbers of pairs decreased from 104 to 68 (35%) after the first week, remained relatively stable for the next 3 weeks, then dropped again during the final 2 weeks. The progressive decrease in pair numbers was similar among species, but was most pronounced at Newcomb Creek and Livingston Park but not Colorado Creek or Lone Pine/Bear Creeks (Table 3). Because ducks were probably migrating through the area during the first week of pair surveys, we averaged the estimated number of pairs for weeks 2-4 to obtain estimates of number of resident breeding pairs for each species (Table 4). Of the 92 estimated pairs of breeding ducks, the majority were mallards (Anas platyrhynchos: 51%) and ring-necked ducks (Aythya collaris; 21%), followed by bufflehead (Bucephala albeola; 13%) and green-winged teal (Anas crecca; 10%). This method underestimated pairs known to have hatched broods for ring-necked ducks at Newcomb Creek and buffleheads at Colorado Creek, Livingston Park, and Upper Beaver Creek. Breeding pair surveys for ring-necked ducks may be biased, because this species did not begin incubation until after surveys ended. Additional waterfowl species observed on the study unit were a pair of sandhill cranes (~ canadensis) at Colorado Creek, a molting male wood duck (Aix sponsa) at Lower Beaver Creek, and several pairs and non-breeding groups of Canada geese (Branta canadensis). The largest group of Canada geese were 14 birds observed at Livingston Park on 25 May. No geese were seen after 7 June. Breeding Chronology Estimated date of hatching was estimated by backdating duckling age using published information on duckling development (Gollop and Marshall 1954). Date of nest initiation was predicted by subtracting mean incubation period (Klett et at. 1986) from the date of hatch (Table 5). Fledging chronology was estimated using values from Bellrose (1976). Nest initiation had already begun upon our arrival on 15 May. Mean date of nest initiation was earliest for mallards and latest for ring-necked ducks, with 5 weeks separating them. Peak of hatch occurred during the last half of June for mallards and green-winged teal, and during mid-July for ring-necked ducks and buffleheads. The resulting hatching curve had a bi-modal distribution of hatching dates (Fig. 8). Mallard hatch spanned 8 weeks, whereas hatching of ring-necked ducks, bufflehead, and greenwinged teal nests spanned only 4, 4, and 3 weeks respectively. Mean date of hatch was latest at Colorado Creek for mallards and ring-necked ducks, and nearly so for bufflehead. Mallards at Upper and Lower Beaver Creeks hatched earlier than in the other 4 units. �234 Table 2. Weekly changes in estimated number of pairs for 8 species of ducks found on Routt National Forest, Colorado, 1990. Numbers with parentheses include Upper and Lower Beaver Creeks to facilitate comparisons between weeks. Species May 16-19 May 22-25 May 28-31 June 1-7 June 11-14 June 18-21 Mallard 42 34 40 30 20 7 (57) Ring-Necked Duck 32 15 16 (48) 20 (19) Bufflehead 16 11 10 8 4 4 1 0 2 2 1 0 0 Total 104 68 76 (108) 0 ( 0) ( 1) 0 ( 0) ( 0) 0 ( 0) 50 (73) 33 (39) 1 ( 1) 0 1 ( 1) ( 0) 0 1 1 1 ( 1) ( 0) ( 2) American Coot ( 2) 2 0 2 6 ( 8) ( 3) ( 0) Common Merganser (7) 3 3 0 5 ( 5) (11) ( 3) Northern Pintail (14) 11 7 3 14 (17) (13) (11) American Wigeon (19) 13 9 4 (8) (24) (15) Green-Winged Teal (30) ( 1) 71 (101) �235 Table 3. Weekly changes in estimated number of pairs found on 6 study units in Routt National Forest, Colorado, 1990. Numbers in parenthesis exclude Upper and Lower Beaver Creek to facilitate comparisons between weeks. May 16-19 May 22-25 May 28-31 June 1-7 Newcomb Creek 54 29 32 32 17 7 Colorado Creek 25 22 21 29 20 15 Livingston Park 17 11 15 9 8 9 8 6 8 1 5 2 Upper Beaver Creek 9 17 14 4 Lower Beaver Creek 23 13 9 2 108 (76) 101 (71) 73 (50) 39 (33) Study Unit Lone Pine/Bear Creeks Total 104 (104) 68 (68) June 11-14 June 18-21 �236 Table 4. Estimated number of breeding pairs for 7 species of ducks found on 6 study units in Routt National Forest, Colorado, 1990. Species Mallard Newcomb Colorado Livingston Creek Creek Park Lone Pine\ Bear Creeks Upper Beaver Creek Lower Beaver Total & Creek (Percent) 14 13 5 3 5 7 47 (51) Ring-Necked Duck 6 6 3 2 1 1 19 (21) Bufflehead 7 1 1 0 2 1 12 (13) Green-Winged Teal 1 2 1 1 1 3 9 (10) American Wigeon 2 0 1 0 0 0 3 (3) Common Merganser 0 1 0 0 0 0 1 (1) American Coot 1 0 0 0 0 0 1 (1) 31 23 11 6 (34) (25) (12) (6) Total Percent 9 12 (10) (13) 92 �237 Table 5. Nesting chronolgy of 5 species of ducks found on Routt National Forest, Colorado, 1990. Species Nest Initiation Mean Date of Incubation Commencment Hatching Fledging Number of Broods Ma11ard 24 May 31 May 25 June 20 August 21 Ring-Necked Duck 21 June 25 June 21 July 10 September 18 Bufflehead 31 May 4 June 3 July 24 August 10 9 June 2 July 6 August 4 Green-Winged Teal 2 June American Wigeon 31 May 1 June 26 June 14 August 1 Common Merganser 10 June 15 June 12 July 15 September 1 American Coot 11 June 17 June 9 July 3 September 1 �238 Pair Density Overall pair density averaged 11.2 pairs/krn", but ranged from 6.0 pairs/krn" at Newcomb Creek to 25.7 palrs/krrr' at Upper Beaver Creek. Newcomb Creek and Lone PlnexBear Creeks had < 10.0 pairs/krn", whereas Colorado Creek, Livingston Park, and Upper Beaver Creek had > 20.0 palrs/km". Because these wetland complexes tend be isolated areas with variable pond densities, pairs per pond is a more meaningful statistic than pairs/krrr' to compare units. Newcomb Creek had the highest pairs per pond (0.62), followed by Colorado Creek (0.40), Livingston Park (0.31), Lower Beaver Creek (0.21), Upper Beaver Creek (0.19), and Lone PinevBear Creeks (0.10). Nest Success .. We did not conduct nest searches, and therefore needed to rely on indices of nest success. Lone male to pair ratios increased throughout the survey period for all species except mallards (Table 6). Interpretation of lone male to pair ratios for ring-necked ducks is questionable because they had just begun nesting at the time surveys were completed. A peak in mallard lone male to pair ratios occurred just before peak incubation commencement, indicating some nest failure occurred during early incubation. In addition, high brood sighting/pair ratios occurred for all species except mallards, further indicating some nest failure occurred for mallards. A consistent increase then steady decline in lone male to pair ratios suggests that nest failure and subsequent repairing of lone males was uncommon among dabbling ducks. Nest 'success appears to be high (6080%) for all species except mallards (40-60%). We only found 3 duck nests incidental to our surveys. A green-winged teal at Colorado Creek hatched all 8 fertile eggs of a 9 egg clutch on 26 June. We found a freshly depredated mallard nest at Lower Beaver Creek on 8 June, which had at least 5 incubated eggs. Another mallard nest bowl with no down or eggs was also found at Lower Beaver Creek on 8 June. Other waterfowl nests included 2 Canada goose nests on beaver lodges at Newcomb Creek and a sandhill crane nest on an island at Colorado Creek. We believe all 3 of these nests hatched, but the sandhill crane lost its young during brooding-rearing. Duckling Survival We found a minimum of 56 broods of 7 species of ducks (Table 7). Number of broods in each area generally reflected estimated breeding pairs (Table 4). However, 51% of the breeding pairs were mallards whereas only 37% of the broods were mallards. In turn, the proportion of ring-necked duck and bufflehead broods was greater than their respective breeding pairs. Also, the proportion of broods at Newcomb Creek (41%) was greater than the proportion of breeding pairs (34%) using this unit. Mean brood size decreased between la and Ib age classes for all species, and continued at a steady decline through class III for bufflehead (Table 8). After the initial decrease, mallards and ring-necked ducks remained relatively constant. Mean brood size for ring-necked ducks again declined at the IIc age class, and average brood size even of young broods was low for this species. The notable increase in size of class IIc and III mallards is a result of relocating several large broods. Data on mean brood size were less reliable for mallards than for other species, because we rarely located mallard broods in 2 consecutive age classes. However, when mallard broods were sighted on 2 consecutive age classes after classes la-Ib, loss of young was recorded on only 1 of 11 occasions. Total Production We estimated waterfowl production using observed and estimated number of young fledged (Table 9). Numbers from observed values represent a minimum because both pair and brood surveys probably underestimated true numbers. To derive our total production estimates we used �239 Table 6. Weekly changes in lone male to pair rat~os for 7 species of ducks found on Routt National Forest, Colorado, 1990. Species May 16-19 May 22-25 May 28-31 June 1-7 June 11-14 June 18-21 Mallard 0.8 :1 1.3 :1 3.7 : 1 3.0 :1 3.2 :1 3.0 :1 0.4 : 1 0.9 : 1 0.3 : 1 0.5 : 1 1.0 : 1 1.8 : 1 0.2 : 1 0.4 :1 0.3 :1 1.0 :1 3.7 :1 4.0 :1 0.4 : 1 1.0 :1 4.5 :1 10.0 : 1 6.0 :1 8.0 :1 American Wigeon 1.0 : 1 0.0 : 1 0.5 :1 0.0 :3 0.0 :2 1.0 :1 Northern Pinta i1 0.0 :0 1.0 : 1 0.0 :0 0.0 :0 0.0 :0 0.0 :0 Common Merganser 0.0 :2 1.0 : 1 1.0 :1 1.0 :1 1.0 :1 0.0 :0 Total 0.5 : 1 0.9 :1 1.6 : 1 1.5 :1 2.3 : 1 3.3 :1 Ring-Necked Duck Bufflehead Green-Winged Teal �242 Table 9. Minimum production estimates for 7 duck species using observed and estimated number of young fledged. Species No. of Fledged Young Broods Estimated Young Number of Young Fledged ger km2 Per Pair Obs. Est. Obs Est. 10 51 140 6.2 17.0 1.1 3.0 Ring-Necked Duck 7 21 55 2.5 6.7 1.1 2.9 Bufflehead 7 18 25 2.2 3.0 2.1 2.1 Green-Winged Teal 1 1 3 0.1 0.4 0.1 0.3 American Wigeon 1 1 1 0.1 0.1 0.3 0.3 Common Merganser 0 a 2 0.0 0 .. 2 0.0 0.2 American Coot 1 7 4 0.8 0.5 7.0 4.0 27 99 230 12.0 28.0 1.1 2.5 Mall.ard Total �243 the following species-specific values: a. b. c. Breeding Pairs = Breeding pair estimates (Table 4) Nest Success = 50% for mallards, 70% for other species Duckling Survival = Mean size of class liB broods (Table 8) therefore: Total Production = axbxc We observed 27 broods age lib or older, totaling 99 young. The estimated potential recruitment from all areas (230 young) was 2.3 times greater than that observed. Observed and estimated production differed substantially for mallards and ring-necked ducks but not for buffleheads. Minimum/Maximum production for each species varied from 0.0-0.2 younq/krrr' for common merganser to 6.2-17.0 younq/krn" for mallards. Observed number of young fledged per pair was greatest for Upper Beaver Creek and Newcomb Creek (Table 10). DISCUSSION Species composition was similar to that found by Ringelman et at. (1989) on Routt National Forest in 1989, except we found no cinnamon teal (Anas cyanoptera), and mallards composed > 10% of the breeding pairs during 1990. Gadwall (Anas strepera) are a common nesting species in Colorado but were not found during this study. In contrast, ring-necked ducks and bufflehead are uncommon breeders elsewhere in Colorado, but were common in Routt National Forest. Gadwall and cinnamon teal prefer more open areas for nesting, whereas bufflehead are commonly found in forested montane wetlands throughout it's range. Ringelman and Kehmeier (1989) first documented a successful nesting pair of bufflehead in Colorado just a year ago. Our results show a range extension for nesting bufflehead, however the range of breeding buffleheads in Colorado is unknown. Mean date of nest initiation was 3-4 days later than that observed in 1989 (Ringelman et al. 1989) for early nesting species (green-winged teal and mallard), but 14-15 days later for late nesting species (bufflehead and ring-necked duck). A similar pattern was evident in the mean date of hatch, but to a lesser degree (2-3 days and 8-10 days, respectively). Wetlands became available to waterfowl 1-2 weeks later in 1990 than in 1989, which could account for the relatively later nest initiation dates. Clutch sizes were less than those reported for prairie-nesting habitats (Klett et al. 1986). Our estimate of 11.2 pairs/km'' was almost double that of 1989 (6.1 pairs/km"), and also exceeded the 1.4 pairs/km" reported by Rutherford and Hayes (1976) and the 0.6 palrs/km" observed by Frary (1954) in forested habitats elsewhere in Colorado. However, number of pairs/pond was similar on the Routt National Forest during 1989 (0.32 pairs/pond) and 1990 (0.30 pairs/pond). Wetland availability could account for the differences in pairs/pond among study units. Newcomb Creek was one of the first areas available (ice-free) to breeding ducks, whereas Colorado Creek was the last. In addition, Bear Creek not only was ice free late, but its location in a steep valley may have made it unattractive to waterfowl. Based on the generally increasing lone male to pair ratios and the high proportion of pairs for which broods were observed, nest success appears to be relatively high in Routt National Forest. Similar results were recorded in 1989. Predators were common in the area, but appeared not to have affected nest success to a great degree. Availability of alternate prey or habitat preferences of foraging predators could account for the lower nest success of mallards than later nesting species. Our minimum estimate of 48% duckling survival is slightly less than the 54% found in 1989 on Routt National Forest. This estimate is only a minimum because of several factors: (1) mallards and green-winged teal tended to be secretive and commonly moved their broods to unknown locations. �244 Table 10. Minimum production estimates for 5 study units using observed number of young fledged. Study Unit Number of Fledged Young Broods Number of Young Fledged per km2 per Pair Newcomb Creek 12 45 5.5 1.4 Colorado Creek 5 21 2.5 0.9 Livingston Park 3 9 1.1 0.8 Upper Beaver Creek 5 14 1.7 1.5 Lower Beaver Creek 2 10 1.2 0.8 27 99 12.0 1.1 Total �245 (2) ring-necked ducks and buffleheads broods tended to disperse and merge by class liB. and (3) we only sampled a portion of the available wetlands. Our estimate fell within the large range of 27-81% duckling survival rates found by others (Ball et at. 1975, Ringelman and Longcore 1982, Talent et at. 1983, Duncan 1986). However, our estimate of 3.7 young fledged per brood was less than the 5.05.5 found in the above studies and the 5.6 ducklings per brood for mallard and green-winged teal found by Frary (1954) in montane habitat of northwest Colorado. Compared to last year, we fledged 10% fewer young per brood, but also appeared to have hatched 22% fewer young per clutch. Thus, although total production of young per brood was less in 1989, percent duckling survival was greater. Reasons for relatively low duckling survival rates are unknown. Mortality rates may have increased when emergent cover became dry, thus making ducklings more susceptible to mammalian predators. Another more likely possibility is that ducklings became separated from adults and died from exposure during the frequent cold or stormy nights. Lone ducklings were commonly observed during brood surveys. To what extent this is a natural occurrence or due to vegetation hindering brood cohesiveness is unknown. Why buffleheads experienced a continuous decline in mean brood size while other species did not is also unknown. Buffleheads usually remained on the same pond throughout brood rearing while other species commonly used several ponds. Predator search images may have focused on ponds in which they were previously successful. In addition, bufflehead ducklings are dependent upon aquatic invertebrates for food. Competition between fish and ducklings for this limited food has been implicated in brood studies of the closely related goldeneye (Bucephala spp.). MANAGEMENT OPTIONS The phase of the reproductive cycle that most inhibited recruitment varied by species and area. Livingston Park, Lone Pine Creek, and Bear Creek did not appear to attract and hold breeding pairs. Nest success appeared to be low for mallards and good for other species. Duckling survival was high for mallards but generally low for ring-necked ducks and buffleheads. Management techniques to attract and hold breeding pairs are generally associated with creating new wetlands, providing additional nest structures or areas, and improving the overall wetland environment. Techniques to improve nest success include habitat predator control and management to improve or provide secure nesting cover. Predator management is not considered a management option for 2 major reasons: (1) it is usually costly, logistically difficult, and largely ineffective in the long term unless continued indefinitely, (2) techniques we used in this study weren't designed to quantify predator effects, thus implementation of predator management without further research could be a waste of time and money. Habitat management to improve food and cover for ducklings are the management techniques most often used to increase duckling survival. The management options discussed below are tailored to the portion of the Routt National Forest covered in this study. Although they may vary in economic and logistic efficiency, all should result in increased waterfowl production. General Treatments The following 3 management options could be applied to all study units. If one or more of these options is selected, we urge that (1) no more than one treatment be applied to a wetland complex, (2) portions of the treated unit(s) be set aside as a control area(s) with no treatment, and (3) that a follow-up evaluation be made to assess the results of the treatment. 1. To reduce separation of ducklings on ponds with dense cowlily growth, an aquatic herbicide (such as Rodeo, a trademarked product from Monsanto) could be applied to produce open travel lanes through some ponds. Most ponds with active beaver colonies naturally maintain such travel lanes. However, most ponds currently choked with cowlily �246 are probably too shallow or lack food to maintain beaver populations throughout winter months. 2. The dominant emergent plants in the area typically grow in less than 0.3 m of water (Windell et aI., 1986). Consequently, they are very susceptible to drying in glacial ponds by the time brood rearing commences and are unlikely to become established in beaver ponds, which tend to have deeper shorelines. To increase cover and food during brood rearing, one might introduce an emergent that has a wider range of water depth tolerances. A promising candidate is hard-stem bulrush. It is currently growing in at least 3 areas in North Park and Routt National Forest. If this treatment is implemented, we suggest planting root stocks during spring or fall at rates of 1,000 plants/acre (Lemberger, 1981). Planting is most easily accomplished by firmly shoving rootstocks into the pond substrate. Establishing hard-stem bulrush by seeding may be more difficult because of the need to scarify seeds (spring seeding) or control water levels (fall seeding) (Harris and Marshall 1960), and because the colder sediment temperatures at this elevation may cause poor germination. 3. Buffleheads are present throughout the study areas. No natural nest sites were located during casual searches this season. Nest boxes erected in early spring also received no documented use. However, surveys conducted near larger wetlands typically used by buffleheads revealed very few natural nesting cavities. Given the age of structure and species composition of the surrounding forest, it is likely that a lack of suitable nest sites limits the breeding population of buffleheads. Rejection of nest boxes this year may be related to the strong homing traditions of buffleheads and/or the relatively few nest boxes installed. Consequently, installation of additional nest boxes is a reasonable strategy to augment breeding populations of this species. Gauthier (1988) found that buffleheads readily use artificial nesting boxes. Maximum dimensions of 15 x 15 x 40 cm with a 6.5 cm hole are recommended (Fig. 9). Several boxes around a pond, placed 3-7 m high and close to the wetland edge, will probably bring best results. Boxes should be placed at larger ponds and ponds with records of pairs that did not produce broods. Colorado Creek The Colorado Creek study unit is virtually devoid of upland nesting cover in clearcut areas. We recommend seeding grasses in clearcut areas adjacent to wetlands to stabilize soils and provide nesting cover for waterfowl. Cattle exclosures should be erected to allow proper development of newly seeded areas and assure residual vegetation is present in early spring. Newcomb Creek This complex has generally high waterfowl production, so care must be taken not to overdo management treatments. Some ponds on Newcomb Creek are in the later stage of wetland succession, and consequently fill with emergents by mid-spring and dry out thereafter. This may attract nesting ducks to the wetland, but then strand broods without suitable rearing habitat. Pond #44 in this unit is an example of a wetland that could be deepened in one or two locations to provide brood habitat and a refugia for aquatic invertebrates during dry periods. Other open water areas could be created using heavy equipment or explosives in select wetlands. �247 Lone Pine Creek Most of the Lone Pine Creek wetland complex consists of old, inactive beaver ponds with failing dams. One approach to rejuvenate this area would require several steps. First, the water levels could be reduced by breaching old dams. Next, the area would be allowed to revegetate into willow and aspen stands. Later, beaver could be reintroduced and maintained by a limited harvest strategy. New beaver complexes are more productive of waterfowl foods and have greater habitat diversity, thus this management strategy would increase the potential for waterfowl production. Livingston Park Livingston Park has high potential for an increased number of wetlands. Currently, the main wetland complex covers only about 30% of the open valley floor. Norris Creek along the south edge of the valley and runoff and surface ground water from a large watershed could supply water for additional, stable wetlands. After a mid-summer rainstorm, six previously dry beaver ponds filled virtually overnight, and the valley floor became saturated with ankle deep water from runoff which persisted beyond the end of the study. If this undependable source of water could be supplemented with water from Norris Creek in the early spring, a stable complex of wetlands could persist throughout the summer months. Beaver are already plentiful in the area and would probably create wetlands if a water source were available, thus keeping the number of man-made impoundments, and cost, to a minimum. Once stable beaver impoundments became established, timing and amount of water from Norris Creek would be targeted to assure persistence of ponds through the waterfowl production season. The exact methods to create this wetland complex are beyond the scope of this study. Among others, consideration of the drainage patterns of the valley and amount of water to maintain additional wetlands would have to be addressed. This management treatment is a large undertaking, but would result in the creation of significant new waterfowl habitat. LITERATURECITED Ball, I. J., D. S. Gilmer, L. M. Cowardin, and J. H. Reichman. 1975. Survival of wood duck and mallard broods in north-central Minnesota. J. Wildl. Manage. 39:776-780. Bellrose, F. C., (ed.). 1976. Ducks, geese, and swans of North America. Stackpole Books, Harrisburg, Pa. 543pp. Coward in, L. M., A. B. Sargeant, and H. F. Duebbert. 1983. Problems and potentials for prairie ducks. Naturalist 34:4-11. Duncan, D. C. 1986. Survival of dabbling duck broods on prairie impoundments in southeastern Alberta. Can. Field-Nat. 100:110-113. Frary, L. G. 1954. Waterfowl production on the White River Plateau, Colorado. M.S. Thesis, Colorado State University, Ft. Collins. 93 pp. Gollop, J. B. and W. H. Marshall. 1954. A guide for aging duck broods in the field. Unpublished report, Mississippi Flyway Council Tech. Sec., 14 pp. Gauthier, G. 1988. Factors affecting nest-box use by buffleheads and other cavity-nesting birds. Wildl. Soc. Bull. 16:132-141. Harris, S. W. and W. H. Marshall. 1960. Germination and planting experiments on soft-stem and hard-stem bulrush. J. Wildl. Manage. 24: 134-139. �248 Klett, A. T., H. F. Duebbert, C. A. Faanes, and K. F. Higgins. 1986. Techniques for studying nest success of ducks in upland habitats in the prairie pothole region. U. S. Fish Wildl. ServoResour. Publ. 158. 24 pp. Lemberger, J. J. 1981. What brings them in? Wildlife Nurseries, Oshkosh Wisc. 32 pp. Ringelman, J. K., and J. R. Longcore. 1982. Survival of juvenile black ducks during brood rearing. J. Wildl. Manage. 46:622-628. Ringelman, J. K., M. A. Willms, and R. S. Langley. 1989. Waterfowl abundance, production, and habitat use on the Routt National Forest, Colorado. Unpublished field report, Colorado Division of Wildlife, Fort Collins, CO. Ringelman, J. K., and K. J. Kehmeier. 1990. Buffleheads breeding in Colorado. Colo. Field Ornith. 24(2):46-47. Rutherford, W. H. and C. R. Hayes. 1976 Stratification as a means for improving waterfowl surveys. Wildl. Soc. Bull. 4:74-78. Talent, L. G., R. L. Jarvis, and G. L. Krapu. 1983. Survival of mallard broods in south-central North Dakota. Condor 85:74-78. Windell, J. T., B. E. Willard, D. J. Cooper, S. Q. Foster, C. F. Knud-Hansen, L. P. Rink, and G. N. Kiladis. 1986. An ecological characterization of Rocky Mountain montane and subalpine wetlands. U.S. Fish Wildl. ServoBioI. Rep. 86( 11). 298 pp. �249 Colorado Division of Wildlife Wildlife Research Report September 1991 JOB PROGRESS REPORT State of Colorado Project W-152-R-4 : Job 22 Work Plan Job Title: _2_ Migratory Game Bird Publications Period Covered: Author: Avian Research - Migratory Game Birds 01 April 1990 through 31 March 1991 Michael R. Szymczak Personnel: James K. Ringe1man and Michael R. Szymczak, Wildlife Colorado Division of ABSTRACT The following list contains those articles that were prepared submitted for publication or published during this segment: and/or Gilbert, D. W., D. R. Anderson, J. K. Ringelman, and M. R. Szymczak. Analysis of duck nesting in relation to vegetation on the Monte Vista National Wildlife Refuge, 1964-90. Wildlife Monograph (In prep.) Ringe1man, J. K. 1991. Differential harvest of mallards under conventional bag and point system regulations. Wi1dl. Soc. Bull. 19:258267. Ringe1man, J. K. 1991. Evaluating and managing waterfowl habitat CoLorado . Co10. Div ..WUdl.,. Div. Rep. 16. 46pp. . . . in . Ringe1man, J. K., M: R. Szymczak, C. W. Jeske, and.K. E. Ragotzkie. Ulnar lipid as an indicator of depleted fat reserves in mal,lards..J. Wi1dl. Manage. (In review). Szymczak, M. R., and E ..A. Rexstad. 1991. Harvest distribution and survival of a gadwall population. J. Wild1. Manage. 55: (In press) . Willms, M., and J. K. Ringe1man. mallards. (In revision) Prepared by: ~ R, ~~ Michael R. Szymczak Wildlife Reasercher C Use of cattle feedlots by wintering � https://cpw.cvlcollections.org/files/original/00180de9a148002f0e3977d2e5105446.pdf 33fd921801c322366e51dd0985b3252c PDF Text Text .1 JOB PROGRESS REPORT State of: Colorado Upland Bird Research Project: 'W-167-R 'Work Plan: _1_: Job Title: Evaluation of Habitat Development for Ring-necked Pheasants in eastern Colorado Period Covered: Author: Job _1!L 01 January through 31 December, 1991 'Warren D. Snyder Personnel: C.E. Braun, T.E. Remington, and 'W.D. Snyder ABSTRACT This study remained in a planning phase through 1991. Some contractual efforts with farmers in extreme northeastern Colorado were conducted on a test basis during spring 1991. Farmers were paid to establish sorghum survival plantings for pheasants on small areas using a modified CHIP (Cooperative Habitat Improvement Program) contract. Quality of the plantings varied widely, but response of farmers was generally favorable. Time and manpower required in preparation of voluminous contracts and slow payment made the approach impractical. Alternate approaches were under review and development. Personnel also reviewed, analyzed, and developed recommendations concerning CHIP, CRP cost share, and other habitat development programs. A report was submitted to Division admi~istrators for review and approval. Prepared by: 1t;1.u.u,) I) ¥ 'Warren D. Snyder 'Wildlife Researcher ��3 JOB PROGRESS REPORT State of: Project: Colorado Upland Bird Research Y-167-R York Plan: 1__ Job Title: Farmin~ for Rin~-necked Pheasants - Pro~ram Development and Evaluation Period Covered: Job __~2=5 __ 01 January through 31 December 1991 Author: Thomas E. Remin~ton Personnel: C1ait E. Braun, Thomas E. Remington, Yarren D. Snyder, Colorado Division of Yi1d1ife. ABSTRACT Ring-necked pheasant (Phasianus co1chicus) populations in Colorado have declined markedly because of habitat loss and degradation resulting from intensive farming. Current cost-share programs do not provide incentives for landowners to develop habitat or reimburse them for income lost from land developed into wildlife habitat. Pheasant hunters have indicated a willingness to pay for hunting opportunity in numerous surveys and by their support of existing fee hunting areas. Ye developed and proposed a conceptual model for a community-based fee hunting program that increases funding for and development of, habitat, controls access, and compensates landowners at minimal cost to the Division of Yi1d1ife in dollars or FTE commitments. ��5 FARMING FOR RING-NECKED PHEASANTS - PROGRAM DEVELOPMENT AND EVALUATION ,, Thomas E. Remington INTRODUCTION Pheasant populations have steadily declined in Colorado over the last 30-40 years. While severe winters have been responsible for occasional die-offs, habitat deterioration caused by intensive farming has been implicated as the cause of long term declines. Preservation or development of pheasant habitat excludes that land from crop production and, thus, represents an economic loss to farmers. While Division of Wildlife (and some Federal) programs have shared the costs of habitat development, no programs have provided economic incentives to replace revenue lost on developed lands, or loss in yields from altering farming practices to benefit pheasants. Pheasant hunters provide significant economic benefits to farming communities by renting motel rooms" eating in restaurants, and by buying gas, groceries, etc. A~though most economic models assume this money "turns over" 2-3 times within these communities, it is unlikely that much, if any, money gravitates to farmers who actually provide the resources which are hunted. On the contrary, hunters (at their worst) represent a source of harassment by trespassing, leaving gates open, damaging fences, fields, etc. Habitat development programs funded by the Division of Wildlife, such as the Cooperative Habitat Improvement Program (CHIP), or the Pheasant Habitat Improvement Program (PHIP; Work Plan 1, Job 24), can begin to replace pheasant habitat losses. However, it is unlikely these programs can restore pheasant populations over a large area for two reasons. First, habitat losses are so extensive that it is unlikely the Division could allocate either enough money, or for a long enough period to completely replace them. Second, some landowners are unlikely to participate in habitat developments on their land or alter farming practices unless they derive an economic benefit from increased pheasant populations, or at least are compensated for lost income. A program to provide additional (non-CDOW) funding for habitat development through economic incentives to landowners to participate could complement existing programs and contribute substantially to improving pheasant hunting in Colorado. Nationally, both participation in, and acceptance of, fee hunting programs is increasing (Smith et al. 1992). Colorado pheasant hunters have indicated a willingness to pay for the opportunity to hunt pheasants through their support of community-based fee hunting programs (i.e., Burlington and Yuma), shooting preserves, and by their responses in the Upland Bird Questionnaire recently conducted by the Upland Bird Program (Upland Bird Management Guide, Colorado Division of Wildlife, 1992). Unfortunately, this payment has not resulted in significant habitat improvements. Revenue generated by the Burlington access fee program, sponsored by the Rotary Club, has been used in part to purchase game farm pheasants for stocking rather than for habitat development. �6 P. N. OBJECTIVES ,, Develop a program to link hunters willing to pay for pheasant hunting opportunity with landowners willing to 1) provide access for a fee, 2) develop habitat~for pheasants within the program area, and 3) amend farming practices to make them more compatible with production and survival of pheasants. SEGMENT OBJECTIVES 1. Meet with farm groups, Chambers of Commerce, sportsman groups (Colorado Wildlife Federation, Pheasants Forever, etc.), Cooperative Extension Service, Agricultural Stabilization and Conservation Service, and Division of Wildlife personnel to identify interest in, and willingness to support, a fee hunting/habitat program for pheasants. 2. If interest level is sufficient, develop draft guidelines for a prototype program in consultation with interested parties from these groups. 3. Disseminate draft guidelines to interested parties for review and amend as appropriate. 4. Present prototype program to appropriate Division personnel for approval to proceed on a trial basis. 5. Select area(s) for implementation and evaluation of prototype program. 6. Prepare detailed study plan for implementation and evaluation of program. RESULTS and DISCUSSION Segment objectives 1-4 were completed. The conceptual framework for a community-based fee hunting program and draft guidelines were presented to the Director's staff in November. Following that meeting the decision was made to defer implementing a prototype program for at least a year to avoid impeding progress on redirecting the CHIP program and implementation of the new PHIP program. In the interim, surveys will be conducted to ascertain hunter interest in a program of this type, the potential market for fee hunting under different fee rates and hunt qualities, and landowner interest and needs. PHEASANT COOPERATIVE PROGRAM The Pheasant Cooperative Program is designed to develop habitat and increase pheasant populations by overcoming several significant barriers to habitat improvement for pheasants and other farm wildlife in eastern Colorado; namely providing financial and other incentives for landowners to develop habitat, offering technical assistance, and generating funding. The Division, landowners, and sportsman will be equal partners in improving pheasant populations and hunting in Colorado. In addition, this program has �educational benefits, increases access for hunting, and should significantly ,, increase pheasant harvest and decrease landowner-sportsman conflicts over hunting. The program minimizes CDOY FIE commitments because sportsman do much of the legwork and habitat developments are completed by landowners and/or sportsmen. At least two communities in eastern Colorado have organized programs to match hunters willing to pay to hunt pheasants with landowners willing to provide access for a fee. These are Ringneck Raiders in Yuma, run by the Future Farmers of America, and Rooster Roundup, run by the Burlington Rotary Club. These programs provide and control access but do not improve habitat and consequently have not increased pheasant populations. Landowners do not receive any proceeds from these programs because they are used as fund-raisers for the sponsoring groups. Hunter satisfaction is poor and organizers may be tempted to stock pen-raised pheasants to the gun to retain hunter interest and dollars. Ye propose that the Division assist in the formation of Community Pheasant Cooperatives consisting of individual farmers and sportsman groups. Hunters would pay a fee to hunt lands within the Cooperative. Some of this money would be paid to the landowners, some would pay for habitat developments within the Cooperative, and a small portion would pay expenses of Cooperative administration. The Division of Yildlife would match hunter contributions for habitat development. Community groups, particularly those which benefit from hunting revenue such as gas stations, restaurants, motels, Chambers of Commerce, etc., would be encouraged to join the Cooperative as sponsors by donating $100, $250, $500, etc. for habitat development. The Division would match these contributions as well. The Division would contract with the Cooperatives while the Cooperatives would contract with the individual farmers. This greatly reduces CDOY FIE requirements to process contracts. Habitat developments would follow prescriptions described in the Pheasant Habitat Improvement Program (PHIP) and would be detailed in individual management plans prepared for each farm in the Cooperative at the outset. It is anticipated that this habitat development money can be used to leverage significant Federal Farm Bill money by paying the farmer's cost share on developments through the Conservation Reserve Program, Forest Stewardship Program, and other Farm Bill programs. Thus, the Division contribution may represent only 25% of total costs. The Cooperative would contract with individual farmers to provide required amounts and quality of habitat, and agree to alter specified farming practices to benefit pheasants (such as timing of stubble tillage in spring to prevent pheasant nest destruction). The Cooperative would also serve as a forum for educational efforts to increase landowner and sportsman knowledge about farming and habitat development practices beneficial to pheasants and other farm wildlife. Many details about how this program would be administered remain to be developed. We believe most details should be left to individual cooperatives since it will be their program. For the Division to participate and cost share developments, habitat plans would have to be developed and habitat quantity and quality goals would have to be met. Cooperatives would be run by a Board consisting of landowner representatives, sportsman representatives, and a CDOY representative. This board would make decisions about program implementation, monitor compliance, and make cash distributions (of hunter fee money). Examples of questions/answers about program implementation details are illustrated in Table 1. Actual programs may differ from this example. �8 Table 1. Questions/answers about Pheasant Cooperative Program implementation. ,, Q. What are significant advantages of this program? A. Provides monetary return to the farmer for access for hunting and burden of hunter control is shifted from the landowner. Farmers are compensated for developing habitat on productive farm ground and this compensation is from groups directly benefitting, i.e., hunters, motels, restaurants, etc. Will significantly increase pheasant populations and harvest at minimal cost to the Division in dollars and FTEs. Access and hunter participation should increase, albeit at a fee. Q. Where will money come from to develop habitat? A. From hunter fees (25-50% to habitat, remainder to farmers after costs). and community sponsors (motels, restaurants, Chambers of Commerce. Pheasants Forever. etc.). The Division of Wildlife would match these contributions. and the entire pool would be used to leverage Federal Farm Bill program $. Q. How much will hunters be charged? A. Rates will be set by individual cooperatives and influenced by supply and demand, but $15/day, $25/weekend. $75/season seem reasonable. Possibilities exist for embellishments such as reduced fees or a sliding scale for youngsters, discounts for mid-week, or surcharges for opening weekend. Q. What about enforcement? A. Additional enforcement to prevent trespass will likely be necessary, at least initially. It is anticipated this program will be self-policing to some extent, because both landowners and hunter participants have a vested interest to prevent trespass. Participating hunters will be identifiable by windshield/dashboard cards and by some form of identification worn on their backs or on their head to facilitate enforcement. Acreage enrolled will be intensively signed (provided by CDOW and erected by cooperative) and participants will be furnished maps. Q. What about liability to landowners and other cooperative members? A. They may be covered under state's general liability immunity (true for participants in South Dakota's pheasant program). If not, liability insurance would be obtained by the Cooperative and paid from fees generated. Q. How will money be paid to landowners equitably. and yet in a manner that encourages habitat and farming practices to benefit pheasants? A. We suggest half of the money to be paid to farmers be allocated based on the amount of land enrolled. The other half would be allocated based on what proportion of pheasants harvested came from that farmers' land, or what proportion of hunters hunted on his land. Evaluation The type, quantity, and distribution of habitat developments will parallel those in PHIP; thus, intensive evaluation of pheasant population responses will not be necessary as they can be inferred from evaluation of PHIP. Evaluation will focus on hunter participation, harvest per unit area and effort, and hunter and landowner satisfaction relative to pre-Cooperative levels and/or similarly farmed areas not in the Program. Acreage of habitat improvements and income generated for farmers will also be documented. �LITERATURE CITED ,, Smith, J. L. D., A. H. Berner, F. J. Cuthbert, and J. A. Kitts. 1992. Interest in fee hunting by Minnesota small game hunters. Wildl. Soc. Bull. 20:20-26 Thomas E. Remington Wildlife Researcher ��1 )~ JOB FINAL REPORT State of: Colorado Project: Y-37-RIW-152-R 'Work Plan: Job Title: 3 Job l3b Responses of Sage Grouse to Vegetation Fertilization Period Covered: Author: Upland Bird Research 1 July 1985 through 31 December 1991 Orrin B. Myers Personnel: C. E. Braun, Colorado Division of 'Wildlife; O. B. Myers, Colorado State University. ABSTRACT I integrated field and laboratory studies to estimate effects of nitrogen fertilization on nutritional quality of big sagebrush (Artemisia tridentata) for sage grouse (Centrocercus urophasianus). By manipulating sagebrush chemistry and morphology on 33 10-ha plots, I tested whether grouse use of 2 sagebrush subspecies was affected. I also used captive sage grouse to experimentally estimate forage preference rankings and nutritional quality. Nitrogen fertilization had large effects on sagebrush morphology and foliar crude protein. Protein content of foliage increased 30 - 52% following treatment but declined rapidly. Morphological changes were more persistent. Sage grouse increased their use of fertilized 'Wyoming big sagebrush (~. ~. xyomingensis, [AT'W])relative to unfertilized AT'Wbut not of fertilized mountain big sagebrush (~. ~. vaseyana, [ATV]). Elevated grouse herbivory rates on fertilized AT'Wwere more persistent than foliar chemistry effects and were correlated with effects on plant morphology. I allowed captive-reared sage grouse to develop feeding preferences for fertilized and unfertilized AT'W and ATV without the confounding influences of variable resource availability or predictability common in field studies. I conducted paired comparison preference trails with these birds and used one-way and factorial BradleyTerry models to estimate preference rankings and the effects of experimental treatments on rankings. Cap.tivebirds developed strong .. preferences for AT'W over ATV, like wild birds, but also increased their consumption of ATV when it was fertilized. I used birds captured from a population that specialized on AT'W during fall - spring and tested their ability to assimilate nutrients from fertilized and unfertilized ATV and AT'W. Assimilation coefficients for drY matter and energy were strongly influenced by the subspecies tested but not by fertilization. Nitrogen balance was not affect by fertilization or subspecies, despite substantial between treatment variation in nitrogen intake. These birds did not fully acclimate to captive conditions and mos.t replications were at sub-maintenance intakes. Although I used analysis models that are less sensitive to level of intake than traditional approaches; potential problems due to captive birds may have prevented detection of fertilization effects. ��,' DISSERTATION SAGE GROUSE HABITAT ENHANCEMENT: EFFECTS OF SAGEBRUSH FERTILIZA nON Submitted by Orrin Bruce Myers Department of Fishery and Wildlife Biology & Program for Ecological Studies In partial fulfillment of the requirements for the Degree of Doctor of Philosophy Colorado State University Fort Collins, Colorado Spring 1992 �14 COLORADO STATE UNIVERSITY March 10, 1992 WE HEREBY RECOMMEND THAT THE DISSERTATION PREPARED UNDER OUR SUPERVISION B:' ORRIN BRUCE MYERS ENTITLED SAGE GROUSE HABITAT FERTn.IZATION ENHANCEMENT: EFFECTS BE ACCEPTED AS FULFILLING FOR THE DEGREE OF DOCTOR OF PHILOSOPHY. Department Head OF SAGEBRUSH IN PART REQUIREMENTS �15 ABSTRACT OF DISSERTA nON SAGE GROUSE HABITAT ENHANCEMENT: EFFECTS OF SAGEBRUSH FERTILIZATION I integrated field and laboratory studies to estimate effects of nitrogen fertilization on nutritional quality of big sagebrush (Artemisia tridentata) for Sage Grouse (Centrocercus urOjlhasianus). By manipulating sagebrush chemistry and morphology on 33 lO-ha plots, I tested whether grouse use of 2 sagebrush subspecies was affected. I also used captive Sage Grouse to experimentally estimate forage preference rankings and nutritional quality. Nitrogen fertilization had large effects on sagebrush morphology and foliar crude protein. Protein content of foliage increased 30 - 52 % following treatment but declined rapidly. Morphological changes were more persistent. Sage Grouse increased their use of fertilized Wyoming big sagebrush (d. 1. wyomineensis, [ATW]) relative to unfertilized ATW but not of fertilized mountain big sagebrush (d. 1. vaseyana, [ATV]). Elevated grouse herbivory rates on fertilized ATW were more persistent than foliar chemistry effects and were correlated with effects on plant morphology. I allowed captive-reared Sage Grouse to develop feeding preferences for fertilized and unfertilized ATW and ATV without the confounding influences of �16 variable resource availability or predictability common in field studies. I conducted paired comparison preference trials with these birds and used one-way and factorial Bradley-Terry models to estimate preference rankings and the effects of experimental treatments on rankings. Captive birds developed strong preferences for ATW over ATV, like wild birds, but also increased their consumption of ATV when it was fertilized. I used birds captured from a population that specialized on ATW during fall spring and tested their ability to assimilate nutrients from fertilized and unfertilized ATV and ATW. Assimilation coefficients for dry matter and energy were strongly influenced by the subspecies tested but not by fertilization. Nitrogen balance was not affected by fertilization or subspecies, despite substantial between treatment variation in nitrogen intake. These birds did not fully acclimate to captive conditions and most replications were at sub-maintenance intakes. Although I used analysis models that are less sensitive to level of intake than traditional approaches, potential problems due to captive birds may have prevented detection of fertilization effects. Orrin B. Myers Department of Fishery and Wildlife Biology & Program for Ecological Studies Colorado State University Fort Collins, CO 80523 Spring 1992 �1./ TABLE OF CONTENfS TITLE PAGE - .. w • • • • • • • • • • • • • • • • • • • • • • • • • •• SIGNATURE PAGE 1 11 iii ABSTRACT OF DISSERTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . .. v TABLE OF CONTENTS ACKNOWLEDG~S Vlll CHAPTER 1 EFFICACY OF NITROGEN FERTILIZATION FOR ENHANCING SAGE GROUSE HABITAT . 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . •. . 1 ME'I"H ODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 INTRODUCTION Study area .•...•................•..•............. 3 Experimental design and treatment of plots •..........•......• 5 Vegetation and soil sampling and analyses Data analysis . .•.................................... RES'ULTS ni . S o il nitrate-nitrogen 7 . ........•........................ 5 9 9 Sagebrush response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11 Sage Grouse response 15 DISCUSSION 20 �18 LI1"ERATURE CI1'ED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 26 < APPENDIX 1 31 CHAPTER 2 BRADLEY-TERRY MODEL ESTIMATION OF PREFERENCE RANKlNGS FROM PAIRED COMPARISON EXPERIMENTS . . . . . . • . . . . . . . . . . .. INTRODUCTION ~ODS 35 . . . . . . . . . . . . • . . . . • . . . . . • . . . . . . . . . . • .. ..•.•.........•.........••..•....•.••... 35 0 37 Paired comparison preference trials . • . . . . . . . . . . . . • . . . . . . . .. 37 Statistical analysis 39 Bradley-Terry models . . . . . . . . . . . . . . . . . . . . . . . . • . . . .. 39 Parameter estimation and hypothesis testing 41 ..•.......•..•.. RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 43 DISCUSSION 46 ...........................•.•..•...... LI1"ERATURE CI fED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 50 APPEND IX 2 •.........•......•.....••..•.••..••.••. S2 CHAPTER 3 EXPERIMENTAL ESTIMATION OF SAGE GROUSE FEE.DIN'G PREFERENCES ......•.•..•...•.•••. INTRODUCTION CI • • • • • • • • • •• 55 . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . • . . . .. 55 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 56 Preference trials . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . • . . . .. 56 Statistical analysis 58 ME11iODS .....•..•..........•..••••.....•.. RESULTS Bradley-Terry model analysis General linear model analysis eo.. ..........•.........•...•.. • • • • • • • • •• 60 60 62 < �DISCUSSION 64 LrrERA TURE CI'TED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 67 CHAPTER 4 EFFECT OF NITROGEN FERTILIZATION ON THE NUTRITIONAL QUALITY OF BIG SAGEBRUSH FOR SAGE GROUSE 69 INTRODUcrI'ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 69 ME'l'HODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . .. 70 Feeding trials 70 Statistical analysis 73 RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 75 DISCUSSION 80 LrrERA TURE CI'TED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 87 �20 ACKNOWLEDGMENTS Support for this work carne from the Colorado Division of Wildlife, the U. S. Bureau of Land Management, the Department of Fishery and Wildlife Biology and its Alumni, the Program for Ecological Studies, and a Colorado Mined Land Reclamation Fellowship. The Arapahoe National Wildlife Refuge, U. S. Fish and Wildlife Service provided facilities to house captive Sage Grouse. I am especially thankful to refuge staff Eugene C. Patten, Raymond N. Varney, and Terri L. Follett for keeping my coffee mug filled. Colorado Division of Wildlife District Wildlife Managers, Kirk F. Snyder and Stephen H. Porter, came through numerous times to help me out of sticky situations and provided hours of welcome entertainment. Drs. Gary C. White and Clait E. Braun served on my graduate committee as co-advisers. I also benefitted from the service of Drs. Richard L. Knight and David M. Swift on my graduate committee. My friends and fellow graduate students gave me much support and stimulation: Robert E. Bennetts, Ada C. Fowler, Frank P. Howe, Leslie A. Robb, Michael A. Schroeder, and last but not least Marilet A. Zablan were the best at this. �< CHAPI'ER EFFICACY OF NITROGEN ENHANCING 1 FERTILIZATION FOR SAGE GROUSE HABITAT INTRODUCfION Sage Grouse, Centrocercus urgphasianus, are sagebrush (Artemisia spp.) obligates (patterson 1952). Over the last half century sagebrush control programs have impacted > 10% of the 20 million ha of this vegetation type on public lands (Vale 1974) and an unknown proportion of the estimated historical total of 38 million ha (Blaisdell et al. 1982). During the same period Sage Grouse also apparently have declined, at least in overall distribution (Braun 1987). Sagebrush stands have been physically removed by plowing, burning, chaining, and herbicide use (Vale 1974, Braun 1987). Although declining numbers of Sage Grouse have been associated primarily with decreasing landscape coverage of sagebrush, reduced quality of remaining sagebrush stands for maintaining grouse populations may have exacerbated the areal loss. Livestock at high stocking density have been cited as having deleterious effects on quality of Sage Grouse and other wildlife habitats (Cooperrider 1990). Habitat fragmentation that occurs concomitant to sagebrush removal operations also has likely reduced the capacity of remaining sagebrush areas to support grouse. Another human-mediated process capable of lowering quality of Sage < �22 Grouse habitats is disturbance caused by human activities, particularly those caused by extraction of petroleum or mineral reserves (Vale 1974, Braun 1987). In many areas inhabited by Sage Grouse, open pit mining operations and other habitat alteration activities can remove or fragment Sage Grouse habitats. Many of these areas are critical habitats for Sage Grouse, especially when sage-covered ridges and benches are affected. available forage in winter. These wind-swept, exposed sites often offer the only Forage quality may not be uniform among or within sites however, as variation in plant chemistry between those plants used and not used as forage by grouse has been reported (Remington and Braun 1985). Part of this observed selectivity was attributable to subspecies of big sagebrush used by grouse. Birds fed mainly on Wyoming big sagebrush [ATW]) and little on mountain big sagebrush CA. t. vaseyana CA. tridentata) CA. t. wyomingensis [ATV]). The population studied by Remington and Braun (1985) also showed significant feeding preferences for plants having higher foliar crude protein and lower monoterpene levels. Although preference studies are not reliable for inferences about herbivore nutritional requirements, one could speculate that grouse select plants on the basis of protein and that increased foliar crude protein could increase their reproductive success (Beckerton and Middleton 1982). Alternatively, foliar monoterpenes or other secondary plant compounds could act as anti-herbivory compounds, thereby lowering the nutritional quality of ATV relative to ATW and causing some plants to be avoided. In either case, plant primary and secondary chemistry may be influenced by resources available to plants (Bryant et al. 1984). Thus, this could represent < �opportunities for improving nutritional quality of sagebrush if resources available to plants can be manipulated. I tested whether nitrogen fertilization of sagebrush altered forage selection patterns of free-ranging Sage Grouse. I examined the effects of nitrogen fertilization on soil nitrate and foliar crude protein dynamics under field conditions. I also examined the responses of free-ranging Sage Grouse to habitat manipulation with fertilizer as a first step in evaluating efficacy of fertilization as a habitat enhancement, mitigation, or remediation tool in sagebrush shrubsteppe. METHODS Study area I conducted my study in North Park, Jackson County, Colorado (40· 50' _. 106· 20'), where Sage Grouse and coal, oil, and natural gas extraction activities cooccur. North Park is an intermountain basin at an elevation of about 2,500 m. It is drained to the north by the North Platte River, which is fed by many smaller streams. Topography is flat to rolling with numerous ridges and benches. Climate is cold and dry with an average annual frost-free period of 46 days. Sagebrush-dominated grasslands cover upland sites, and grasses and sedges occur in native and irrigated meadows that border drainages. Artemisia tridentata is the dominant sagebrush species and includes 2 subspecies, A. 1. wyomin~ensis and A. 1. vaseyana. Other species of sagebrush occurring with limited distribution in North Park are A. lon~iloba, A. sana. and A. auil10sa (Beetle 1960). �24 MODERATE HIGH -., LOW JACKSON COUNTY • FERTILIZED D CONTROL 1 km FIg. 1-1. Study plot locations in North Park, Jackson County, Colorado. Locations were stratified into areas expected to have low, moderate, and high levels of grouse use. �25 Experimental desien and treatment of plots In October-November < < 1985 granular ammonium nitrate fertilizer (33.5% N) was applied at a rate of 112 kg-N/ha to 33 fertilizer treatment plots using conventional agricultural spreaders. Locations for 33 experimental blocks were chosen by restricted randomization among 3 strata (Fig. 1-1) predicted as having low, moderate, and high levels of winter use by Sage Grouse (C. E. Braun, personal communication) within the McCallum anticline area of North Park (Beekly 1915) where petroleum development has occurred. The 11 blocks in each stratum were 20 ha in size. Their dimensions in the low and high-use strata were about 183 x 1094 m. In the moderate-use stratum, blocks were about 366 x 547 m due to constraints of terrain. The long axis of each block was east-west. Each block was divided in half along the long axis and fertilization treatments (fertilized or control) were assigned at random to each half. In October 1987 fertilizer was applied to 6 additional randomly-located l-ha treatment plots. Unfertilized plots were not true controls, because fertilizer spreaders did not traverse the plots. Vegetation and soil sampling and analyses Focus for the study was on early-spring forage selection by grouse to coincide with the period when maternal nutrition might most likely affect Sage Grouse reproduction. I sampled 12 randomly-selected blocks in the 4 years subsequent to the first growing season response to fertilization; the springs of 1987-90 correspond to years 1 - 4 of the experiment. May. Sagebrush foliage was sampled in mid-April to early Equal numbers of each subspecies were sampled along transects in control and fertilized plots of randomly-selected study blocks. Sampling points were at random �26 distances along transects. Stems and leaves from 5 plants of each subspecies at each level of fertilization were clipped, bagged, and placed on dry ice or snow, and then stored in a freezer. Once leaves were separated from stems, equal amounts from each plant were pooled and ground in a mortar and pestle under liquid nitrogen and frozen until chemical assays were performed. Kjeldahl nitrogen (Horwitz 1980) was measured to estimate foliar crude protein (% nitrogen x 6.25) in addition to neutral detergent fiber (NDF) and acid detergent fiber (ADF) (Van Soest 1963,a,h; Mould and Robbins 1981; Van Soest 1982). Gross energy estimates were obtained by bomb calorimetry. Coumarin content of sagebrush leaves was indexed by percent transmittance following Welch and McArthur (1986). Sage Grouse use of study blocks was estimated by examining individual plants for evidence of feeding activity prior to removing stems for analysis of foliar chemistry. The characteristic appearance of leaves that have been fed upon by grouse was described by Remington and Braun (1985). I scored plants as 1 if fed upon by grouse or 0 if not. I described sagebrush growth responses by measuring new growth of stems on plants. Three stems were measured from plants along 20-m transects in 5-m segments. Density within l-m wide strips and canopy cover along transect lines also were measured in the 3 blocks I sampled in each stratum. I scored each transect segment as 1 if ~ 1 plant was fed upon by grouse or 0 if no plants had been used by grouse. �27 I used the 6 I-ha blocks fertilized in 1987 to estimate the response of soil nitrogen to fertilizer treatment. Two experimental blocks located on Bosler loam and 4 were on Morset loam (Fletcher 1981). In June of each year 6 subsamples from the A and B horizons were pooled from each subplot. Soil chemistry analyses were performed by the Colorado State University Soil Testing Laboratory, Fort Collins (Workman et al. 1988). Data analysis Foliage samples came from random subsets of the blocks available, thus experimental units were not completely independent between years nor were repeated measurements made on the same experimental units in each year. I used nonlinear least-squares regression models to describe responses of sagebrush foliage to fertilization following Potvin et al. (1990). My global model for jointly describing the data and for testing hypotheses about the responses of the 4 sagebrush treatments over time consisted of each treatment level being estimated by its own exponential decay model of the form: (1.1) I systematically reduced the parameter space of the global model to test hypotheses about the responses of sagebrush and to obtain more parsimonious models. I assessed the significance of the reductions in parameter space by computing E-ratio tests between full and reduced models (Zar 1984): �28 << (1.2) ResSSlt is the residual sums of squares obtained by fitting the reduced model having q parameters, ResSSpis the residual sums of squares obtained by fitting the full model having p parameters (p > q), and n is sample size. I reduced the exponential models to linear least-squares models to test for linear trends in time. Parameter estimates from curve-fitting exercises can have ecological interpretations beyond that available from inferential methods (potvin et ale 1990). I constructed tests about parameter estimates and computed E-ratio tests or Student's 1 tests for the equality of 2 parameters (Zar 1984). My times series data consisted of winter-spring foliage chemistry for years 1-4 after the initial growth response by sagebrush. I coded year as (year-I) before analyses to aid in interpretation of parameter estimates. My observations of Sage Grouse herbivory on plants formed binary responses suitable for maximum likelihood logistic regression of the probability of grouse herbivory on subspecies and fertilization status of plants (pROC CATMOD, SAS Institute, Inc. 1988; Hosmer and Lemeshow 1989). I also scored each pooled foliage sample as 1 if ~ 1 plants were fed upon by grouse or as 0 if no plants in the pooled foliage sample had been fed upon by grouse. Pooled foliage samples assayed for crude protein represented 5 plants for each combination of block, subspecies, and fertilizer treatment level. Standard logits of binary responses were regressed on subspecies and foliar crude protein to estimate their effects on probability of grouse herbivory using maximum likelihood logistic regression where �L':1 (1.3) and where fJ is the probability of grouse herbivory on at least 1 plant in a pooled sample of 5, given the crude protein content (x) of the foliage. I collected soil samples from the same experimental units in each year and used repeated measures analysis of variance (ANDV AR, PRDC GLM, SAS Institute, Inc. 1988) when analyzing soil nitrate-nitrogen data. I used univariate ANDV AR hypothesis tests and multivariate ANDV AR profile analysis to examine the response of soil nitrate-nitrogen to fertilization treatments during years 1-3. Mauchly's criterion was used to test the assumption of compound symmetry for the variancecovariance matrix, and Greenhouse-Geisser (G-G) corrected probability values were used to establish the significance of tests if the variance-covariance asymmetrical. matrix was The G-G tests were the most conservative of the adjusted E tests (SAS Institute, Inc. 1988). RESULTS Soil nitrate-nitrocen Prior to fertilization in October 1987 (Year 0) control and treatment plots contained similar nitrate-nitrogen levels (f = .363, Fig. 1-2). The following June treatment plots contained about 9x the nitrate-nitrogen levels of controls. By year 2 nitrate-nitrogen on fertilized plots decreased to 170% of controls and decreased to 122% of controls in year 3. Averaged over 3 years, soil nitrate-nitrogen was �30 increased by fertilization (f = .043, Table 1-1), with the size of this effect changing over time (f = .031). Maucbly's criterion test for sphericity of the variance- covariance matrix rejected (f = .023) due to high variance in year 1, so probabilities for within subject tests were based on Greenhouse-Geisser adjusted F tests. The magnitude of the treatment effect declined (f = .038) between the first and second years after fertilization, however, fertilized plots still retained greater (f = .025) soil nitrate-nitrogen levels than controls in year 2. By the third year after treatment soil nitrate-nitrogen returned to control levels (f = .587). Other soil parameters showed little variation in response to fertilization (APPENDIX 1). ,,--.... E 00....._.... 10 CONTROL 8 FERTILIZED Z w C) 0 6 ~ ~ Z 4 I w ~ « ~ 2 ---...-~ ~ Z 0 0 2 1 __ ..._.. •••••• 3 YEAR Fig. 1-2. Nitrate-nitrogen (::r ± SE) dynamics of soils in control and fertilized plots in North Park, Jackson County, Colorado. << �31 Table 1-1. Univariate repeated measures analysis of variance of soil nitrate-nitrogen measured from f-ha study plots. Probabilities for within subjects effects were based on Greenhouse-Geisser adjusted E tests. Source of variation df F MS Between subjects Blocks 5 4.27 0.59 .709 Fertilizer 1 52.56 7.30 .043 Error 5 7.19 2 20.84 5.24 .066 10 4.57 1.15 .439 2 33.15 8.33 .031 10 3.98 Within subjects Years Years*blocks Years*fertilizer Error Sa,eebrush response Fertilization produced dramatic changes in plant structure so that treated plots were readily identifiable without the aid of plot markers when I was on foot, in vehicles or in fixed-wing aircraft. Fertilized plots were easily recognizable during the first and second years after treatment, less so in the third year, and were difficult to identify without plot markers and a compass in the fourth year. The annual growth increment of sagebrush in the first year more than doubled, and number of reproductive structures increased many times (personal observation), which apparently contributed to the visual differences between fertilized and control plots. for fertilized ATV (FATV) was 7.1 em + 0.2 New growth (SE), which was about 240% of < ' �32 controls, compared to 7.3 em ± 0.3 for fertilized ATW (FATW) and 2.9 em ± 0.2 for ATW. Density of sagebrush plants (! = 3.3 plants/rrr', f = .639) and canopy cover were not altered by fertilization (! = 11%, ~ = .815). Total plant height of ATV, excluding reproductive structures, increased from 26.8 to 31.8 em after fertilization ~ = .005), but height of ATW was not affected (! = 23.4 em .f = .560) Total big sagebrush cover differed between strata ~ = ± 0.9, .031) with the expected low-use stratum having 15% canopy cover compared to 10% in the moderate-use stratum and 7% in the high-use stratum. Cover values for each subspecies differed between strata as density for each subspecies varied among strata ~ < .001). Density of ATV in the low-use stratum averaged 3.1 plants/m" compared to 1.1 and 0.6 plants/nf in the high and moderate-use strata, respectively. The low-use stratum contained the lowest density of ATW (! = 0.5 plants/m~ = 2.6, compared to the other strata ~ Licb = 2.0). Total density of big sagebrush did not vary among strata (.f = .734). Crude protein in the foliage of unfertilized ATV and ATW varied between r = 0.10, Fig. years with a weak linear trend (.f = .004, more crude protein (.f < .001, I = 12.45%, SE SE = 1-3), but ATW contained 0.26) than ATV (X = 10.14%, = 0.22). Gross energy content of ATV (! = 23.80 kJ/g) was greater than ATW (! = 23.04 kJ/g), but NDF re = .003) ex = 0.266, f = .125) and ADF (! = 0.181, .f = .124) were similar for each subspecies. Transmittance at 364 nm was higher for ATW (23.6%) than in ATV (10.9%) indicating higher ~ < .001) coumarin levels in ATV relative to ATW . < < �33 _.... 24 ATV ~ 0 o ~20 ...__ ATW A FATV FATW -.- z A w 16 r0 a::: CL w 0 :::> 0:: 8 .------_. ---------'-".~~+ ~-----~ ------------~ -~$ U a::: « 4 _J 0 u, o 1 2 4 3 YEAR Fig. 1-3. Foliar crude protein levels (x % DM spring in years subsequent to fertilization. ± SE) of big sagebrush during early Foliar crude protein in fertilized sagebrush subspecies increased and then declined exponentially in the years subsequent to fertilization (Fig. 1-3). Fertilizer treatments increased foliar crude protein by 52% for ATV and 30% for ATW in the first year of response (Fig. 1-3). In each year, but year 2, fertilized sagebrush contained more crude protein than unfertilized sagebrush ~ < .03). In year 2 FATW contained more protein that ATW ~ = .038). Two jointly estimated functions for FATV and FATW gave a better fit to the data ~ = 0.80) than a single function ~ < .001, Table 1-2). Exponential decay �34 Table 1-2. Parameter estimates for nonlinear models describing responses of sagebrush to fertilization. < < Model Full Parameters al (Ji A; Reduced a· I Estimate 95% CI r FATV 10.03 8.67 - 11.39 0.80 FATW 13.64 12.49 - 14.80 FATV 7.24 5.43 - 9.06 FATW 8.48 6.79 - 10.17 FATV 1.59 0.41 - 2.76 FATW 2.36 0.34 - 4.38 FATV 10.02 9.03 - 11.01 FATW 13.69 12.71 - 14.68 Treatment level (J FATV &.FATW 7.84 6.61 - 9.07 x FATV &.FATW 1.95 0.89 - 3.00 models not only gave a good summary of the data cr - also can have meaningful ecological interpretations. 0.79 0.80), but the parameters The asymptotic level of crude protein in foliage was estimated by a. Thus, a test of the hypothesis that aj = a was equivalent to testing LTV = L1W. Asymptotic protein levels in foliage were not the same for FATV and FATW (Table 1-2, :e < .(01). These levels did not differ from the average level for ATV (f = .561) but did for ATW (f = .032). The initial effect of fertilization on each subspecies was estimated by {J. Under the null hypothesis {Ji = 0, and if {JFATV ¢ {JPA1Wthere subspecies x fertilizer interaction. was evidence for a I found no evidence of significant subspecies x fertilizer interaction effects (Table 1-2, :e = .327), and fertilization increased each subspecies by 7.84 percentage points over unfertilized controls <:e < .001). Hypothesis tests about a and {J resemble between-subjects tests in an ANOV AR, while A described the rate of decline in foliar crude protein and was �analogous to ANOV AR within-subjects tests. The 2 subspecies I tested had the same exponential decay constant (Table 1-2, f = A71). Precision of A was low (cv = 37 - 43%), however, relative to the other parameters (cv = 7 - 16%), and power to detect a difference between ~ of this size (0.77) was only about 11 %. I formed a reduced model for predicting the functional responses of FA TV and FA TW by estimating common a and P and separate A for each subspecies (Table 1-2). The reduced model did not differ from the full model in the amount of explained variation ~ = .263, r = 0.79). The form of the response by FATV and FATW, therefore, differed only in the predicted asymptotic protein levels. Foliar crude protein in FA TW was a predictable function of ATW from adjacent control plots and time since fertilization (f < .001, r = 0.753). This relationship was (1.4) FATW - ATW + 9.066e-1.547(ycar-l). Fertilization did not influence estimated gross energy ~ = .844), or ADF ~ = .370) of sagebrush. <e = .468), NDF Although I detected significant site effects (Blocks, f = .014) on coumarin levels, these differences were not related to sampling strata ~ = .880). Sage Grouse response During my 4 years of monitoring rates of Sage Grouse herbivory on sagebrush plants the proportion of plants used by grouse in a season varied between 4 and 8 % • Total herbivory rates on ATW plants (0.120 ± 0.016) were higher than on ATV < < �36 < <. 0.35 ... ,.-, ATV ATW ---0--FATV ~FATW -6-- 0.30 >- 0::: 0.25 0 > co 0.20 • 0:::: W I L-.J 0.15 rn 0 0::: 0.10 0.. 0.05 __.. .. 0.00 1 ::::===:::--. 3 2 4 YEAR Fig. 1-4. Probability of sage grouse herbivory (J> years subsequent to fertilization. (0.012 ± 0.005, :f ± SE) on big sagebrush plants in < .001). No trend was evident in total herbivory rates for either subspecies during the study ~ = .315). Although total herbivory did not change, shifts in foraging locations of grouse were inferred from the observed rates on plants in fertilized and control plots (Fig. 1-4). Herbivory rates were greater on FATW than on ATW in year 1 ~ = .004) and year 2 (f < .001) but not in year 3 ~ = .063) or year 4 (f = .508). Sampling effort for estimating herbivory rates was not intensive, so only differences >0.25 could be detected with 95% probability at ex = 0.05. Increased sampling effort of n = 80, 120, and 250 plants in each treatment group would have �.)1 been necessary to detect differences of 0.2, 0.15, and 0.10, respectively with the same probability. For ATW and FATW, I partitioned the 3 df from year effects into single df contrasts. The average herbivory rate for FATW during years 1 to 3 differed from the herbivory rate in year 4 ~ = .039). The same contrast for ATW was not significant ~ = .492). The average herbivory rates in year 1 and 2 were not different from the average rate for year 3 and 4 for FATW ~ ~ = .075) or ATW .186). Herbivory rates on ATV and FATV were low and no annual or treatment effects could be detected (f > .1). (1 - = e c Power to detect these effects was low 0.30). I summarized annual patterns of Sage Grouse herbivory rates on ATW and FATW using linear and quadratic logistic regression models. The model containing terms for intercept, year, and treatment x year, where year = to, 1, 4, 9}, = produced the best fit to the data (likelihood ratio goodness-of-fit X:4 1.53, f = .822). The joint model for predicting probability of herbivory on ATW and FATW was: 1Pr (herbivory I year, treatment) - 1- 1 1 + e -1.Gl2 • -O.IlS)'etr 1 1 + e -3.176 • O.079)'etr ' 1.42, £ = I observed no strata x treatment interaction (x22 = , FATW (1.5) ATW .491) effects on herbivory rates, but total herbivory on ATW and FATW did vary among strata (x21 = 19.46, £ < .001). Total herbivory on the ATW subspecies was not related to �38 <- 1.00r--------------ATV ,...., ••••••••• 0.80 .. .. ... """": ..... :o---..., ' ' ....•. ....• ....••. ....'. . ATW ' .........,... 0.60 ......' 0.40 ~ >o > .........~ 0.20 ,;' •...•~ ,--... 0:: ....... ..•... . ,. »" ___ ........• --. ........• ~. ........... .. .•....~ ,. • Ii•• ••• , co O.OO~~---~---~--~---~--~ W 1.00r----------------~-___, 0:: I "-" rn o g: 0.80 .'.' .. ..... .' ' 0.60 .. .' .. ." 0.40 ..••.' ' ...... .. .' .' ........ ,-: ' ' ............. ,.... 0.20 •.•..•. ........... 0.00~-8~~~10----~12-----1~4-----1~6----~18 FOLIAR CRUDE PROTEIN (% DM) Fig. 1-5. Predicted herbivory rates for sagebrush samples from experimental plots. Dotted lines are 95 % confidence intervals. The approximate probability for a single plant is P(O.2). ' �Table 1-3. Parameters for logistic prediction of sage grouse herbivory rates from foliar crude protein (Fig. 1-5). The approximate probability for a single plant is p15. Likelihood ratio goodness of fit Parameters Model 111 110 2 Subspecies: ATV -4.658 0.218 ATW -4.879 0.353 -6.873 0.496 Combined f>~ .701 .685 plant density when density of ATW was substituted for strata (likelihood ratio goodness of fit X-2 = 5.43, f = .066). The high-use level of strata had an observed probability of grouse herbivory of 0.063 (SE = 0.020), significantly lower than what I observed in the moderate-use (p = 0.188 + 0.033, f = (p = 0.118 ± 0.027, £ = .(03) and low-use strata .002). I used crude protein estimates obtained from pooled foliage samples and Sage Grouse herbivory scores to estimate the probability of herbivory in relation to foliar crude protein (Fig. 1-5). The 2 subspecies model was adequate for joint prediction of subspecies-specific herbivory rates on ATV and ATW plants (likelihood ratio goodness of fit, f = .700, Fig. 1-5). However, this model was indistinguishable from a reduced model that predicted herbivory rates for both subspecies with a single function ~ = .281, Fig. 1-5, Table 1-3). For both models, prediction of the probability of herbivory on individual plants was approximated by P(0.2) since analyses were conducted on pooled foliage samples. �40 DISCUSSION There is little dispute that sagebrush shrubsteppe has been altered by human activities and that further impacts will continue (Vale 1974, Braun 1987). One potential means for manipulating habitat quality for Sage Grouse is use of nitrogen fertilizer. Fertilization treatment used in this study produced changes in soil nitrate- nitrogen and sagebrush chemistry and structure that caused an increase in the use of treated sites by grouse. The rapid decline in soil nitrate-nitrogen likely was due in part to increased growth increments and increases in foliar crude protein. Movement of nitrogen deeper into the soil profile and uptake of soil nitrogen by grasses, forbs, and soil microbes also contributed to loss of nitrate-nitrogen (Schimel and Parton 1986). Mineralization of organic nitrogen should have continued to provide inorganic nitrogen for sagebrush in later years, which probably accounts for significant elevations of crude protein in sagebrush foliage 4 years after treatment. Variation among sites occupied by ATV and ATW could account for different asymptotic FA TW levels from ATW but not for FATV and ATV. Nitrogen mineralization varies spatially and temporally with soil moisture, temperature, and the availability of other nutrients controlling nitrogen mineralization at small spatial and temporal scales (Burke 1989). Although ATV and ATW plants sometimes were separated by < 1 m, they tend to segregate by soil depth and topography (Burke et al. 1989). ATW tends to occupy sites with warmer soil temperatures and shallower soils relative to ATV (West 1983) and could be limited more by soil moisture than ATV. Fertilized plots tended to capture and hold more �"'t.J.. snow than control plots, which could delay onset of spring growth but provide additional soil moisture. Total herbivory rates on sagebrush did not change during the study. One interpretation of this observed constancy is that numbers of grouse on the study area were not affected by fertilization. My estimates of herbivory rates did not include an estimate of the amount of biomass removed; thus increased rates of tissue removal from individual plants could not be detected. I cannot evaluate, therefore, whether grouse population size on the study area changed in any way as a result of fertilization. Birds shifted foraging activities at least within scales of S 300 m, as shown by the higher herbivory rates on fertilized plots relative to controls. Fertilization may have shifted grouse foraging activities at greater spatial scales, but I did not have data on Sage Grouse behavior before and after treatment upon which to base an evaluation. The probability of grouse herbivory on ATW plants was a predictable function of foliar crude protein. Remington and Braun (1985) used crude protein and plant vigor in discriminant function analysis on pooled plant samples to discriminate between browsed, unbrowsed, and random plants, but discrimination was poor. By substituting predicted foliar crude protein levels in fertilized sagebrush based on unfertilized plant chemistry and time since treatment (1.4) into the model that predicts herbivory rates from foliar crude protein (Table 1-3), I summarized expected results obtained by fertilizing sagebrush having different levels of crude protein (Fig. 1-6). The increase in the probability that a sagebrush plant was used as forage by grouse may be greatest on sites where crude protein is lowest prior to fertilization, but the �42 .,--.... w (f) 0.15 ~ .....__.., 0::: CL. o W 0.10 0.05 (f) « w 0::: o U 1 Z 10 4 Fag. 1-6. Predicted increase in herbivory rates on sagebrush plants in relation to prefertilization foliar crude protein (% DM) and time after treatment. benefits may also decrease most rapidly at these sites. However, effects of fertilization may still be > 0 after 4 years, regardless of initial conditions. Although the probability of herbivory on plants was related to crude protein, patterns of herbivory I observed over time had a qualitatively different response: the response of foliage and herbivory rates predicted on the basis of foliar crude protein was concave, whereas the measured herbivory response was convex. The general appearance of fertilized sagebrush over the 4 years varied in a way that was consistent with the observed herbivory response, which suggests that plant morphology is an important determinant of forage selection. Remington and Braun (1985) previously detected a correlation between their subjective assessment of plant vigor and grouse �43 use. Red Grouse lLagopus la~2Pus scoticus) also increased their use of fertilized sites ' over unfertilized sites that differed both in plant appearance and chemistry (Miller 1968). Fertilization altered the appearance and chemistry of both subspecies, but only ATW was used regularly by Sage Grouse. Remington and Braun (1985) suggested that ATV was unsuitable forage due to plant secondary chemistry. One may speculate that increased dietary nitrogen produced by fertilization could overcome certain negative effects of plant secondary compounds (Remington 1990). Why then were FATV plants not used more by grouse? Variation in sagebrush chemistry among plants (Remington and Braun 1985, Welch et al. 1988), populations and subspecies (Welch and McArthur 1979, 1981), and species (Kelsey and Shafizadeh 1979) is not unusual, but plant chemistry has not always correlated well with feeding preferences (White et al. 1982, Hupp 1987). Variation exists also in the sagebrush taxa used by Sage Grouse as forage. For example, Sage Grouse studied by Hupp (1987) used only ATV and Sage Grouse studied by Welch et al. (1988) fed upon ATV, ATW, and A. 1. tridentata. Forage use efficiencies have been correlated with grouse feeding preferences (Remington 1990). These observed preferences could be a result of localized adaptations to variation in forage quality ranldngs or could be due to more dynamic physiological adaptations to forage quality rankings that are conditional upon forage availability. For the North Park Sage Grouse I studied, ATW was, on average, more available to grouse than ATV. ATW tends to occupy sites more likely to be exposed during winter. If there is a transient cost associated with dietary switching (Levey and Karasov 1989), foraging preferences for ATW should have �44 evolved and my failure to detect a fertilization effect in FA TV would be caused by confounding influences of availability and not because forage quality was not adequate. Even if availability was even, time-lagged responses of grouse due to experience and learning could have been important (Wiens et al. 1986). Prediction of grouse use areas from earlier studies with other objectives were not adequate for predicting intensity of grouse use. Designation of grouse use areas apparently was a function of sampling intensity, although spatial shifts in grouse-use areas could have occurred. Pretreatment description of grouse use area and grouse herbivory rates probably would have expedited more effective placement of experimental units and would have provided a background upon which to judge the effectiveness of fertilization for increasing the total amount of foraging on the study area. The predicted low-use stratum may provide the best opportunity of the strata I used for continued testing of Sage Grouse-sagebrush foraging relationships. The stratum had the highest density of ATV, yet received the highest degree of herbivory by grouse. Numerous small patches of ATW that were a few metres in diameter occurred among the ATV. These ATW patches were completely covered by snow in some years, thereby reversing the typical availability ranking for the 2 subspecies. Additional study of grouse foraging dynamics on fertilized and unfertilized sites in this strata could reveal increased use of FA TV with time. Estimation of the relationships between Sage Grouse herbivory and plant chemistry in this and other studies (Remington and Braun 1985, Hupp 1987) were limited by pooling plant samples before chemical assays. Nested sampling designs �would better allow assessment of plant chemistry and grouse foraging at the scales of plants, sites, subspecies, and species and would aid identification of the appropriate units for management actions. Fertilization of sagebrush shrub steppe with 112 kg-N/ha sufficiently altered soil and plant chemistry to the extent that Sage Grouse exhibited localized shifts in foraging sites to treated areas. Whether or not fertilization caused the total number of birds using the study area to increase could not be assessed due to insufficient information on pretreatment conditions. Treated sagebrush foliage contained increased levels of crude protein 4 years after treatment. Sage Grouse herbivory rates on ATW were increased by fertilization but seemed to have no effect on ATV, although time lags in Sage Grouse responses could have prevented my detection of this effect. Whether use of fertilized sagebrush will have substantive nutritional benefits for Sage Grouse requires information on use efficiencies of forages and nutritional requirements of grouse. Fertilization was predicted to have the largest effect on Sage Grouse herbivory rates on sagebrush in areas where foliar crude protein was lowest. Regardless of initial conditions, fertilization should increase the probability of use of preferred subspecies for forage with benefits potentially lasting 4 seasons or more. Nitrogen fertilization therefore has potential for locally increasing the probability of feeding by grouse within areas already used by grouse. By fertilizing within Sage Grouse habitats, land managers might shift grouse-use areas away from impact areas. The increase in growth of fertilized sagebrush might also speed remediation of degraded sagebrush shrub steppe. < < �46 LITERATURE CITED Beckerton, P. R., and A. L. A. Middleton. 1982. Effects of dietary protein levels on Ruffed Grouse reproduction. Journal of Wildlife Management 46:569-579. Beekly, A. L. 1915; Geology and coal reserves of North Park, Colorado. U. S. Geological Survey Bulletin 596, 121pp. Beetle, A. A. 1960. A study of sagebrush-section Tridentatae of Artemisia. University of WYQmingAgricultural Experiment Station Bulletin 368. 83pp. Blaisdell, J. P., R. B. Murray, and E. D. McArthur. 1982. Managing intermountain rangelands-sagebrush-grass ranges. U. S. Department of Agriculture, Forest Service, General Technical Report INT-I34. 41pp. Braun, C. E. 1987. Current issues in Sage Grouse management. Proceedings of the Western Association of Fish and Wildlife Agencies 67:134-144. Bryant, J. P., F. S. Chapin, m, P. Reichardt, and T. Clausen. 1984. Adaptation to resource availability as a determinant of chemical defense strategies in woody plants. Recent Advances in Phytochemistry 19:219-237. Burke, 1. C. 1989. Control of nitrogen mineralization in a sagebrush steppe landscape. Ecology 70: 1115-1126. Burke, I. C., W. A. Reiners, and R. K. Olson. 1989. Topographic control of vegetation in a sagebrush steppe landscape. Vegetatio 84:77-86. Cooperrider, A. Y. 1990. Conservation of biological diversity on western rangelands. Transactions North American Wildlife and Natural Resources Conference 55:451-461. �'+1 Fletcher, L. A. 1981. Soil survey of Jackson County area, Colorado. U. S. Deparrnent of Agriculture, Soil Conservation Service, U. S. Government Printing Office 237-568/69, Washington, D.C, USA. 159pp. Horwitz, W., editor. 1980. Official methods of analysis of the Association of Official Analytical Chemists. Association Official Analytical Chemists., Washington, D.C., USA. 1018pp. Hosmer, D. W., and S. Lemeshow. 1989. Applied logistic regression. John Wiley and Sons. New York, N. Y. USA. 307pp. Hupp, J. W. 1987. Sage Grouse resource exploitation and endogenous reserves in Colorado. Ph.D. Thesis, Colorado State University, Fort Collins. 73pp. Kelsey, R. G., and F. Shafizadeh. 1979. Sesquiterpene lactones and systematics of the genus Artemisia. Phytochemistry 18:1591-1611. Levey, D. J., and W. H. Karasov. 1989. Digestive responses of temperate birds switched to fruit or insect diets. Auk 106:675-686. Miller, G. R. 1968. Evidence for selective feeding on fertilized plots by Red Grouse, hares and rabbits. Journal of Wildlife Management 32:849-853. Mould, E. D., and C. T. Robbins. 1981. Evaluation of detergent analysis in estimating nutritional value of browse. Journal of Wildlife Management 45:937-947. Patterson, R. L. 1952. The Sage Grouse in Wyoming. Sage Books, Denver, Colorado, USA. 341pp. �48 Potvin, C., M. J. Lechowicz, and S. Tardif. 1990. The statistical analysis of ecophysiological response curves obtained from experiments involving repeated measures. Ecology 71:1389-1400. Remington, T. E. 1990. Food selection and nutritional ecology of blue grouse during winter. Ph.D. dissertation. University of Wisconsin, Madison. 116pp. Remington, T. E., and C. E. Braun. 1985. Sage Grouse food selection in winter, North Park, Colorado. Journal of Wildlife Management 49:1055-1061. SAS Institute, Inc. 1988. SAS/STAT'" user's guide, release 6.03 edition. SAS Institute, Cary, North Carolina, USA. 1028pp. Schimel, D. S., and W. J. Parton. 1986. Microclimatic controls of nitrogen mineralization and nitrification in shortgrass steppe soils. Plant and Soil 93:347-357. Vale, T. R. 1974. Sagebrush conversion projects: an element of contemporary environmental change in the western United States. Biological Conservation 6:274-284. Van Soest, P. J. 1963.a,.Use of detergents in the analysis of fibrous feeds, I. Preparation of fiber residues of low nitrogen content. Journal of Association Official Agricultural Chemists 46:825-829. ___ . 1963}2. Use of detergents in the analysis of fibrous feeds. n. A rapid method for the determination of fiber and lignin. Journal of Association Official Agricultural Chemists 46:829-835. ___ . 1982. Nutritional ecology of the ruminant. 0 and B Books, Inc., Corvallis, Oregon, USA. 374pp. �Welch, B. L., and E. D. McArthur. 1979. Variation in winter levels of crude protein among Artemisia tridentata subspecies grown in a uniform garden. Journal of Range Management 32:467-469. Welch, B. L., and E. D. McArthur. 1981. Variation of monoterpenoid content among subspecies and accessions of Artemisia tridentata grown in a uniform garden. Journal of Range Management 34:380-384. Welch, B. L., and E. D. McArthur. 1986. Wintering mule deer preference for 21 accessions of big sagebrush. Great Basin Naturalist 46:281-286. Welch, B. L., J. C. Pederson, and R. L. Rodriguez. 1988. Selection of big sagebrush by Sage Grouse. Great Basin Naturalist 48:274-279. West, N. E. 1983. Western intermountain sagebrush steppe. Pages 351-374 in N. E. West, editor. Temperate deserts and semideserts. Ecosystems of the World Series. Volume 5. Elsevier, New York, New York, USA. White, S. M., J. T. Flinders, and B. L. Welch. 1982. Preference of pygmy rabbits (Brachyla~us idahoensis) for various populations of big sagebrush (Artemisia tridentata). Journal of Range Management 35:724-726. Wiens, J. A., J. T. Rotenberry, and B. Van Horne. 1986. A lesson in the limitations of field experiments: shrub steppe birds and habitat alteration. Ecology 67:365-376. Workman, S. M., P. N. Soltanpour, and R. H. Follett. 1988. Soil testing methods used at Colorado State University for the evaluation of fertility, salinity and trace element toxicity. Technical Bulletin LTB88-2. Colorado State University Cooperative Extension, Fort Collins, USA 29pp. ,' �50 Zar, 1. H. 1984. Biostatistical analysis. Second edition. Prentice-Hall, Englewood Cliffs, N. 1., USA 62Opp. �J.L < < APPENDIX 1 APPENDIX 1-1. Soil chemistry estimates from study plots in North Park, Jackson County, Colorado, at time of fertilization (Year 0) and in subsequent growing seasons (Years 1-3). Within subjects and between subjects effects tested were Years x Fertilizer and Fertilizer, respectively. Control Soil parameter Conductivity Cu Fe K MD NO~ Year l>f Fertilized I SE I SE 0 0.2 0.03 0.1 0.03 1 0.2 0.03 0.3 0.03 2 0.2 0.02 0.2 0.02 3 0.5 0.03 0.5 0.03 0 2.1 0.06 2.1 0.06 1 1.9 0.09 1.7 0.09 2 8.5 0.21 8.7 0.21 3 2.5 0.27 2.8 0.27 0 23.9 1.99 24.0 1.99 1 14.9 2.56 19.6 2.56 2 22.1 1.54 21.0 1.54 3 23.5 1.90 20.6 1.90 0 231 10.5 205 10.5 1 194 7.9 203 7.9 2 218 11.0 208 11.0 3 235 24.3 241 24.3 0 3.0 0.14 2.9 0.14 1 2.0 0.14 2.4 0.14 2 2.2 0.11 2.1 0.11 3 3.5 0.59 3.7 0.59 0 0.6 0.06 0.7 0.06 1 0.8 1.53 7.0 1.53 Between subjects Within subjects .441 .120 .552 .528 .879 .236 .847 .732 .424 .697 .043 .031 �52 APPENDIX 1-1. Continued. Control Soil parameter OM P pH Zn Year :1 SE Fertilized :1 SE 2 1.0 0.15 1.7 0.15 3 1.8 0.39 2.2 0.39 0 3.1 0.15 2.9 0.15 1 1.8 0.19 1.8 0.19 2 2.6 0.09 2.3 0.09 3 1.8 0.16 1.5 0.16 0 4.2 0.35 3.7 0.35 1 2.6 0.19 2.8 0.19 2 2.0 0.17 2.3 0.17 3 3.0 0.62 3.6 0.62 0 6.8 0.13 6.7 0.13 1 7.5 0.21 7.2 0.21 2 7.1 0.02 7.0 0.02 3 6.8 O.OS 6.9 0.05 0 0.8 0.07 0.8 0.07 1 0.4 0.06 0.5 0.06 2 0.5 0.01 0.5 0.01 3 0.6 0.08 0.5 0.08 '. < P>F Between subjects Within subjects .132 .627 .280 .762 .471 .388 .844 .188 �)j APPENDIX 1-2. Crude protein dynamics (% DM) in sagebrush foliage subsequent to fertilization in October-November 1985 from study plots in Jackson County, Colorado. ANOV A summary Year Month 1986 May ATV ATV ATV ATV ATV ATW 1988 April 17.27 0.70 Subspecies <.001 No 13.00 0.52 Fertilizer <.001 Yes 22.12 0.65 SxF .016 No 8.83 0.17 Blocks .501 Yes 10.74 0.27 Subspecies <.001 No 10.64 0.37 Fertilizer <.001 Yes 11.59 0.22 SxF .167 No 8.42 0.20 Blocks .017 Yes 9.09 0.22 Subspecies No 10.75 0.29 Fertilizer .026 Yes 11.82 0.56 SxF .166 No 8.54 0.14 Blocks .001 Yes 9.93 0.37 Subspecies <.001 No 11.47 0.29 Fertilizer <.001 Yes 12.82 0.53 SxF .939 No 11.40 0.16 Blocks .564 Yes 11.52 0.46 Subspecies No 12.86 0.55 Fertilizer .118 Yes 14.45 0.75 SxF .177 No 8.72 0.38 Blocks .049 Yes 10.17 0.46 Subspecies No 12.27 0.34 Fertilizer .153 Yes 13.95 1.30 SxF .811 No 8.56 0.23 Blocks .006 Yes 10.29 0.20 Subspecies No 11.68 0.38 Fertilizer .002 Yes 13.54 0.89 SxF .858 Yes ATW 1988 January <.001 10.73 ATW 1987 May Blocks No ATW 1987 February 0.36 ATV ATW 1986 November f>E Fertilizer ATW 1986 August Source Subspecies ATV ATW ! SE <.001 <.001 <.001 <.001 c, e, �54 APPENDIX 1-2. Continued. ANOV A summary Year Month 1988 June 0.24 Blocks .296 7.81 0.17 Subspecies .001 No 9.71 0.68 Fertilizer .461 Yes 10.41 0.24 SxF .084 No 7.91 0.32 Blocks .003 Yes 7.86 0.35 Subspecies No 10.29 0.21 Fertilizer .914 Yes 10.99 0.48 SxF .135 No 9.40 0.21 Blocks .003 Yes 10.11 0.37 Subspecies No 12.05 0.50 Fertilizer .026 Yes 13.76 0.80 SxF .202 ! ATV No 8.37 Yes ATV ATW 1989 April f>f .Fertilizer ATW 1988 October Source Subspecies ATV ATW SE <.001 <.001 �< < CHAPTER 2 BRADLEY-TERRY MODEL ESTIMATION OF PREFERENCE RANKINGS FROM PAIRED COMPARISON EXPERIMENTS INTRODUCTION Ecologists often use animals in experimental situations to establish preference or avoidance rankings for objects with different properties. These objects or subjects may differ naturally as in coloration or size or may differ because their attributes were manipulated by the experimenter. Preference rankings of objects or experimental treatments often are estimated from cafeteria-style trials where each test animal is permitted to choose among several objects or alternatives simultaneously. The response of interest is whether or not a particular object is selected in each trial. Examples of how selection may be registered are the mass of each test ration consumed, the total leaf area removed, the number of bites taken of each forage, or the number of other behaviors observed in reference to each object during the trial. Thus, each object or treatment accumulates some sort of preference score during the test interval, be they grams, bites, or number of courtship displays. Analyses of these data generally follow analysis of variance procedures or contingency table analyses. When one or more test objects are strongly preferred or avoided certain conditions or assumptions relevant to statistical procedures can be violated, especially �56 those of homogeneity of variances and the minimum number of observations per cell. Cafeteria-style trials also may have low ability to discriminate rankings of the less preferred objects. For example, consider the alternatives offered to a human community regarding the fate of a local stream: a) allow a stretch of highly-prized trout stream to remain undeveloped and undegraded, b) construct a moderately-sized dam and reservoir to help meet several community needs and, at the same time, inundate 50% of the stream, c) construct a larger reservoir that floods 75% of the stream but provide mitigation elsewhere at a rate of 3 miles of mitigation to every mile of inundated stream, and d) construct a large dam that floods the entire stream reach but provide no mitigation. If an angling club devoted to stream fishing was asked "Which option do you prefer: A, B, C, or D?", then one might expect results to highly favor response A. The preferred alternative for this population would be identified without providing much information about less desirable but possibly acceptable alternatives. cafeteria-style. A similar situation could arise when testing animal forages One highly preferred forage with high nutritional value that generally is in short supply could be used with little or no use of other more abundant but nutritionally adequate alternatives. An alternative to cafeteria trials for estimating preference rankings is to use paired comparison trials where each subject chooses among test objects or treatments offered in all possible pair-wise combinations (David 1988). For the dam example where responses were multinomial, responses are binomial when alternatives are evaluated with a paired comparison design. When responses are continuous each pairing of treatments can be treated as separate experiments where treatments are �57 paired and analyzed as paired 1 tests. For each pairing one can compute multiple tests of the hypothesis that each alternative in a pair has the same probability of being preferred. An acceptable overall experimentwise error rate can be achieved by applying the Bonferroni inequality to the a-level for each pairing. The continuous data situation also may be handled as a balanced incomplete block design, which should be more efficient and would enable analysis of factorial as well as one-way treatment structures. A combined analysis of qualitative responses from paired comparison experiments is possible in a way that is analogous to the normal-theory balanced incomplete block design. I use results of paired comparison feeding preference trials to demonstrate the utility of Bradley-Terry models (Bradley and Terry 1952) for estimating preference rankings. I also show the model can be reparameterized to include factorial treatment structures of ecological experiments. METHODS Paired comparison preference trials I used 4 sage grouse in paired comparison preference trials to estimate the preference rankings of 4 sagebrush treatments formed by factorial combinations of 2 levels of subspecies (Artemisia tridentata vaseyana [ATV] and A. 1. wyomingensis [ATW]) and 2 levels of nitrogen fertilization (fertilized [PATV and FATW] and unfertilized [ATV and ATW]). Ammonium nitrate (33% nitrogen) was applied to sagebrush rangeland in North Park, Jackson County, Colorado at a rate of 112 kg- N/ha: in a randomized complete block design (Chapter 1) to manipulate foliar < < �58 chemistry. In winters after the first year of growth response, I removed leaves from plants for estimating feeding preferences of grouse. The 4 treatment levels of the 2 x 2 factorial treatment structure were grouped into the 6 possible pairs and assigned an identification code at random. I presented each pairing to birds in paired comparison preference trials. Preference trials involved simultaneous presentation of sagebrush leaves in 400-ml beakers to each bird, allowing it to feed for 60 min, and estimating the fresh mass intake to the nearest 0.1 g of each treatment in the paired comparison. Position of treatments on the left or right side of each cage was randomized, and positions were switched on the subsequent replication of the experiment. Mass changes of control sagebrush leaves were used to estimate moisture loss during each trial. Birds were fasted overnight prior to each trial, and trials commenced in the first hour after sunrise. Simultaneous to intake-based preference trials, I observed onset of feeding by birds. At the start of each replication, I retreated from view of the birds and recorded the first beaker into which each bird approached and initiated feeding. I defined the initiation of feeding as whenever a bird broke the plane formed by the top of the beaker with its beak. I scored these treatments as preferred (1) and the beakers not used first as not preferred (0). If a bird did not initiate feeding within 15 min both treatments were scored as not preferred. I also scored the intake assays as 1 or o on the basis of relative intakes so that feeding initiation patterns could be compared with feeding preferences over longer periods. << �Statistical analysis Bradley-Teny models.-I used a series of models based on the Bradley-Terry (BT) model (Bradley and Terry 1952) to estimate preference ranks of each treatment from paired comparison preference trials. The behavioral assay for forage preference consisted of independent Bernoulli trials where a bird was scored as preferring (1) or not preferring (0) treatments in paired comparisons. If only 2 objects or treatments existed and were compared by several judges (or birds), the probability of choosing object i over objectj in a paired comparison is estimated by the number of times object i is selected divided by the total number of choices made (i + J). Likewise, the probability of choosing object j over object i is the number of wins by object j divided by the total number of paired comparisons. These probability estimates are simple binomial probabilities that can be represented as Tij' the probability of object i being chosen over object j in a paired comparison of the 2 objects. The BT model can be applied to situations where I objects, 1'" 1'2' ••• , 1'" are compared by n judges, with the 'Ythjudge making r~ replications of all possible (~) combinations. When an object i is selected over object j in a paired trial by judge 'Y making the oth comparison of i and j it can be scored as a random variable, a, such that 1 indicates preference for the object in the trial and 0 indicates the object was not preferred. Let this random variable be represented as: ~, i,j = 1,2, ... , I, i=Fj; 'Y = 1,2, ... , n; 0 It is assumed that all comparisons are independent so that independent, except for ~ + aj~ = = aij-,~ 1,2, ... , r.,. are mutually 1. The probability of object i being chosen over objectj in a particular paired comparison is represented as Pr(a~ = 1) = TiirO �60 with the restriction that 0 ~ 1 and that the sum of all preference probabilities Tij,& ~ within a paired comparison is 1. Assuming no effects due to replication or due to judge then the BT model simplifies to its basic form: T, Tij where Tij • (0 :S ~--~ (T.I +. T.) J T; :S 1, r, T, • 1, i ¢j). (2.1) is the probability of object i being preferred over objectj in a paired comparison. Parameters -,rj and Tj are the preference probability rankings of particular objects over the paired-comparison experiment to be estimated from measurements from the pair-wise preference probabilities, Tij. Thus, the Tj estimate the probability of each treatment being selected when t objects are compared. Under Ho: Tj = T = for estimating = lit Tj 0.25 for the model in this experiment. The likelihood equation has the form (Bradley 1976): n T, il, !£(T, la,) • --'--- n<.J (T, + T,)"" (aj• r , '" , a..), (2.2) fI I where aj are the row sums of the preference scores in a preference matrix when preferences are scored as 1 or 0 by each judge in each paired comparison. The a; also rank preferences when designs are completely balanced. Independent maximum likelihood estimates of (t - 1) preference probabilities are achieved via solution of the likelihood equations (Bradley 1976), �61 , I (i • 1, 2, ... , t and r it - 1) . (2.3) i E j "i I reparameterized the basic B-T model to test for main effects of subspecies (a) and fertilization (/1) in a 2 x 2 factorial framework (Abelson and Bradley 1954, Table 2-1). The multiplicative parameterization of subspecies and fertilizer effects reproduce the Ti when the interaction term (0) allows the effects of fertilizer to vary among levels of a. Parameter values for a and ~ were constrained to the interval o - 1 and 0 must lie between -1 and 1. The null hypothesis for the factorial model thus was Ho: a = 0.5, ~ = 0.5, and 0 = O. In my paired comparison experiments I tallied the number of times sagebrush treatment i was chosen over treatment j in the 6 possible pairings of 4 treatments. Treatment positions in cages were randomized and reversed in 2 replications for each bird. I assumed there were no nonrandom effects due to individual birds. Parameter estimation and hypothesis testing.-lterative numerical estimation of parameters was accomplished using Program SURVIV (White 1983). The program constructs the likelihood functions from the BT model (2.1), uses the observed cell values to produce maximum-likelihood estimates of the unknown parameters by solving the likelihood equations (2.2), and constructs likelihood ratio tests between nested sub models that are formed by constraining one or more of the parameters to their values under H,', The software also can perform Monte Carlo simulations for evaluating power associated with pre-planned hypothesis tests. Overall adequacy of models used in tests and for estimating parameters was assessed with likelihood ratio < �62 Table 2-1. Parameterization of Bradley-Terry models for one-way and 2 x 2 factorial classifications of treatments. Factorial parameterization One-way parameterization 1- Tl - T2 - T3 Subspecies (a) Fertilizer (1 - a) (1 - (J) (/3) a T2 (1 - a) T3 a ATV + 0)] [1 - (/3 Tl Sagebrush treatment ATW {J (/3 FATV + 0) FATW goodness-of-fit tests and using Akaike's Information Criterion (AlC) (Akaike 1973), defined as AlC = -2ln(~ + 2(number of parameters estimated). The AlC is useful in selecting the most parsimonious model upon which to base inferences (Lebreton et al. 1992). I used the basic BT model to obtain summary statistics for each of the 4 sagebrush treatments. I obtained estimates of rATW, TpATV' and TpATW and their associated standard errors directly from Program SURVIV using the basic BT model. Preference probability for ATV was estimated as that ETi = 1 (Table 2-1). I estimated variance of T' ~, u! + 2T' u.. ~ i «] 'r,,'ffJ TATV = TATV 1- rATW - TpATV - TpATW as (Steel and Torrie 1980:109). The factorial model parameterization was equally general, compared to the so �OJ basic model, when interaction effects were included and was used to test hypotheses about the effects of subspecies and fertilization on feeding preferences of grouse. By constraining one or more parameters in the factorial BT model to their expected values under Ho: a sequence of nested submodels was constructed that, when tested .- against their more general alternatives, were analogous to tests about effects in a 2 x 2 factorial analysis of variance. with df = Tests were likelihood ratio x- tests calculated as dfRcduced - dfOcacra.l. RESULTS I compiled preference matrices from scores (0,1) for each pairing of treatments in the behavior and intake assays (Table 2-2). Rows contain counts of the number of times the row treatment was preferred over the treatments heading up each column. The row sums (aJ were used in solving the likelihood equations (2.2), but the preference matrix was used as data input (APPENDIX 2). The basic 3-parameter BT model predicted that treatment selection based on initiation behavior was a random process (,(-3 Behavioral scores). not cover 0.25. = 4.746, f = .191, Table 2-2: Only FATV had an asymptotic 95% confidence interval that did Several trials could not be used in the analysis because some birds did not initiate feeding within 15 min. I used 1000 Monte Carlo simulations to estimate statistical power to reject the null hypothesis that at least 1 Power was about 0.4 for this example. Tj ¢ 0.25. , < �0'\ -'" Table 2-2•. Preference matrices and estimated preference probabilities (i-) from intake and behavioral paired comparison preference trials for sagebrush. Parameter estimates Preference matrix Sagebrush treatment ATV ATW FATV FATW al i- SH 95% CI Behavioral scores 2 ATV ATW 3 FATV 1 2 FATW 3 3 4 2 8 0.257 0.103 0.054 - 0.458 6 4 13 0.383 0.113 0.161 - 0.603 3 6 0.116 0.050 0.018 - 0.215 11 0.245 0.086 0.077 - 0.414 5 Intake scores 0 ATV ATW 8 FATV 5 0 FATW 8 5 3 0 3 <0.001 <0.001 -0.001 - 0.001 8 3 19 0.374 0.009 0.357 - 0.392 0 5 <0.001 <0.001 -0.002 - 0.002 21 0.626 0.008 0.609 - 0.642 8 �65 I was able to score all intake based trials (Table 2-2: Intake scores). Preference probabilities were not equal for all treatments .f = < .(01). ~3 < = 45.372, Two treatments did not receive non-zero scores when paired against the other 2 treatments and caused their preference probabilities to approach zero. The other 2 treatments were used significantly more than expected by chance (Table 2-2). The presence of this many zeros in the preference matrix also caused rounding errors to dominate the numerical solution algorithm after parameters were estimated to 3 significant digits. The strong preference for ATW and FATW in the one-way BT model analysis was expressed in the factorial BT model analysis as a strong effect by the a (subspecies) main effect (Table 2-3). Tests for factorial effects correspond to model a_ft_o vs. a_ft for the interaction effect (0), model a_ft vs. f3 for the subspecies effect, and a _ft vs. a for the fertilization effect. Each model also can be tested against the null model (In[;e:] -25.2204, df = 6, Ale = 50.4407), where all parameters were constrained to their assumed values under Ho. These results in an analysis of variance table format indicated non-significant effects for subspecies x fertilization interaction ~ > .999), and fertilization (f = .315) and a strong effect on selection probability due to subspecies ~ < .001). The small Ale for model a indicates it was the best-fitting, parsimonious summary of these data. Factorial model analysis of the behavioral scores revealed no significant main effects (Table 2-4). Power to detect differences of this size was not good null model (In[~ (f = -9.4352, df = 6, Ale = « 0.30). The 18.8704) gave an adequate fit to the data .489), but its Ale was larger than for model a {3. Under this model an ATW < �66 Table 2-3. Factorial Bradley-Terry model analysis of paired-comparison preference trials for sagebrush. Data are scored intake values and parameterization follows (Table 2-1). Model parameters estimated afJa afJ fJ a In(~ df AIC G-O-P- -2.5343 3 11.0686 >.999 -2.5343 4 9.0686 >.999 -24.9697 5 51.9394 <.001 -3.0397 5 8.0793 .962 Likelihood ratio tests between models General submodel Reduced sub model Main effect tested afJa afJa afJa afJ afJ afJ fJ a fJ a Interaction Subspecies had a 0.356 + 0.964 df 0.001 1 >.999 44.871 2 <.001 1.011 2 .603 44.871 1 <.001 1.011 1 .315 Fertilizer • Likelihood ratio goodness of fit test f > subspecies had a 0.644 )(2 ± f>)(2 t. 0.096 probability of being selected and a fertilized plant probability of being selected. DISCUSSION A strongly preferred object in a cafeteria-style preference trial should be chosen in accordance with its preference probability, leaving few if any observations < < �01 Table 2-4. Factorial Bradley-Terry model analysis of paired-comparison preference trials for sagebrush. Data are scored feeding behaviors and parameterization follows (Table 2-1). Model parameters estimated In(!:e) df Ale G-O-F" apo ap -7.0624 3 20.1248 .8760 -7.1489 4 18.2977 .9301 P -8.1843 5 18.3685 .7105 a ":8.1843 5 18.3685 .7105 Likelihood ratio tests between models General sub model Reduced sub model Main effect tested expo expo apo ap exP exP p ex p ex Interaction df ~>-K 0.173 1 .6775 2.244 2 .3257 2.244 2 .3257 Subspecies 2.071 1 .1501 Fertilizer 2.071 1 .1501 • Likelihood ratio goodness of fit test f -K > -K. for addressing the relative preferences of the remaining objects. Thus, paired comparison experiments potentially are more powerful for discriminating preferences among several objects (David 1988). When preferences for objects can only be scored subjectively as 1 or 0, the BT model can be used to estimate the individual probabilities of the objects tested in paired comparison experiments. be generalized and reparameterized This model can to account for replication effects, within-pair e, < �68 1.0 0.8 ~ 0.6 ~ 00.4 ~ 0.2 '1t' UNDER Ha: N Fig. 2-1. Empirical estimates of power to detect differences from T = 0.50 with a factorial Bradley-Terry model for several sample sizes and alternative hypotheses. Power was estimated from 1000 Monte Carlo simulations of each scenario. ordering effects (Bradley 1976) and, as I have done, to test for factorial effects (Abelson and Bradley 1954). If a judge evaluates every possible paired combination of objects, the resultant situation is equivalent to a Round-Robin tournament in sport where every player competes against every other player. The problem of obtaining rankings of multiple objects from paired comparisons was first given attention by Zermlo (1929) (cf. David 1988) in attempting to rank chess players and again by Bradley and Terry (1952) while developing statistical methods for sensory difference tests (Bradley �1976). The BT model was formulated to deal with the situation where t objects (or treatments) are compared and scored by n judges in ~~) paired comparisons. Paired comparisons have an advantage over cafeteria-style comparisons when objects can only be judged subjectively and when fine-scale judgements are otherwise difficult by extraneous influences from the presence of > 2 objects (David 1988). The influence of multiple objects may confound preference scoring in cafeteria trials especially when different object attributes or combinations of attributes drive choices in different pairings of objects. For example, color might drive choices of fruits chosen by foraging birds, but other cues related to ripeness or nutrient content may influence choices within or between color classes. The approach is to formulate a general model using the parameters of interest and to fit increasingly reduced models to the data until the "best" fitting model is selected, given the data. Tests of hypotheses can be formulated based on sets of sub models. By constraining a parameter equal to some nominal value or equal to another parameter, the parameter space is reduced. The remaining parameters then are estimated under an imposed constraint that corresponds to an assumption about the nature of the data. This assumption can be tested by performing a likelihood ratio test against the more general model. I tested the hypotheses that effects of a (subspecies), {3(fertilization), and (a x (3) did not influence the preference probabilities for sagebrush. ° The full factorial BT model (model a_ft_o) produced individual T identical to the basic BT model (2.1). To form the test for a significant interaction effect I constrained ° = O. Tests of main effects, a and {3,were estimated by constraining a = 0.5 and {3 = 0.5 in model , ' �70 a_fi to produce models f3 and a, respectively, and calculating the likelihood ratio x: relative to a_fi. Bradley-Terry models suffer from reduced efficiency relative to normal theory analogs under optimal conditions (Bradley 1955). These models are useful, however, for data sets that do not meet assumptions for analysis of variance. Numerical solution of likelihood equations is no longer a problem; the software I used has capabilities for modeling many conditions (White 1983). The method of paired comparison experiments to estimate preference and avoidance rankings should have broad applicability in studies of sexual selection and mate choice, forage selection, or evaluating the efficacy of feeding deterrents. LITERATURE Abelson, R. M., and R. A. Bradley. comparisons. Akaike, H. CITED 1954. A 2 x 2 factorial with paired Biometrics 10:487-502. 1973. Information theory and an extension of the maximum likelihood principle. Pages 267-281 in B. N. Petran and F. Csaki, editors. symposium on information theory. Second edition. International Akademiai Kiadi, Budapest, Hungary. Bradley, R. A. 1955. Rank analysis of incomplete block designs. ID. Some large- sample results on estimation and power for a method of paired comparisons. Biometrika 42:450-470. -_. 1976. Science, statistics, and paired comparisons. Biometrics 32:213-232. �11. Bradley, R. A., and M. E. Terry. 1952. Rank analysis of incomplete block designs. I. The method of paired comparisons. Biometrics 16: 178-188. David, H. A. 1988. The method of paired comparisons. Charles Griffin, London, England. 188pp. Lebreton, J. D., K. P. Burnham, J. Clobert, and D. R. Anderson. 1992. Modeling survival and testing biological hypotheses using marked animals: a unified approach with case studies. Ecological Monographs. 62:67-118. Steel, R. G. D., and J. H. Torrie. 1980. Principles and procedures of statistics. McGraw-HilI, New York, New York, USA. 633pp. White, G. C. 1983. Numerical estimation of survival rates from band-recovery and biotelemetry data. Journal of Wildlife Management 47:716-728. Zermlo, E. 1929. Die Berechnung der Turnier-Ergebnisse als ein Maximumproblem der Wahrscheinlichkeitsrechnung. Mathematische Zeitschrift 29:436-460. < < �72 '. APPENDIX 2 APPENDIX 2-1. Example of SURVW (White 1983) input file used to analyze paired comparison preference trial data with a one-way Bradley-Terry model. PRoe TITLE BRADLEY-TERRY MODEL ANALYSIS: ONE-WAY MODEL: PRoe MODEL NPAR=3: eOHORT=5 1* Total Dumber paired comparisons: pairing 1 */: 2:(I.DO-S(1 )-S(2)-S(3»/«I.00-S(1 )-S(2)-S(3» + S(1» 1* Wins by ATV in pairing 1 *1; 3:S(I)/«1.00-S(I)-S(2)-S(3»+S(I» 1* Wins by ATW in pairing 1 *1; COHORT = 5 1* Total Dumber paired comparisons: pairing 2 *1; 4:(I.00-S(1 )-S(2)-S(3»/«1.00-S(1 )-S(2)-S(3» + 5(2» 1* Wins by ATV in pairing 2 *1; 1:S(2)/«1.00-S(I)-S(2)-S(3»+ S(2» 1* Wins by FATV in pairing 2 *1; eOHORT=S 1* Total Dumber paired comparisons: pairing 3 *1; 2:(I.00-S(I)-5(2)-S(3»/«I.DO-S(1)-5(2)-S(3» + 5(3» 1* Wins by ATV in pairing 3 *1; 3:S(3)/«I.00-S(1)-S(2)-S(3»+ S(3» 1* Wins by FATW in pairing 3 */: COHORT =8 ,. Total Dumber paired comparisons: pairing 4 *1; 6:S(I)/(S(I) + 5(2» 1* Wins by ATW in pairing 4 */: 2:5(2)/(S(I)+ S(2» /* Wins by FATV in pairing 4 *'; eOHORT=8 /* Total Dumber paired comparisons: pairing 5 */; 5:5(1)/(5(1)+5(3» /* Wins by ATW in pairing 5 */; 3:5(3)/(5(1)+5(3» /* Wins by FATW in pairing 5 */: COHORT = 8 /* Total Dumber paired comparisons: pairing 6 */; 3:5(2)/(5(2) + 5(3» /* Wins by FATV in pairing 6 *'; 5:S(3)/(5(2) + 5(3» /* Wins by FATW in pairing 6 *1; LABELS; 5(1)=PROB(ATW) SELECTED; S(2)=PROB(FATV) SELECTED; S(3)=PROB(FATW) SELECTED: 1* (1.DO-S(I)-5(2)-S(3»=PROB(ATV) SELECTED *1 PRoe ESTIMATE NAME = GENERAL; INITIAL; 5(1)=0.2; 5(2)=0.01; S(3)=0.4; PROe ESTIMATE NAME=NULL; INITIAL; 5(1)=0.25; CONSTRAINTS: 5(1)=5(2); S(I)=S(2): S(I)=S(3); PROe TEST; PROe STOP; ' �1.5 APPENDIX 2-2. Example of SURVIV (White 1983) input me used to analyze paired comparison preference trial data with a factorial Bradley-Terry model. PROC TITLE BRADLEY-TERRY MODEL ANALYSIS: FACTORIAL MODEL; PROC MOOEL NPAR=3; 1* Total number paired comparisons: pairing 1 *1; COHORT= 5 2:(1.00-S(I»*(1.00-(S(2)+S(3)))1 «1.00-S(I»*(I.00-(S(2)+S(3)))+S(I)*(1.00-S(2))) 1* Wins by ATV in pairing 1 *1; 3:S(I)*(I.00-S(2»/«I.DO-S(1»*(I.00-(S(2)+S(3»)+S(I)*(1.00-S(2») 1* Wins by ATW in pairing 1 *1; 1* Total number paired comparisons: pairing 2 *1; COHORT=5 4:(I.00-S(I»*(I.DO-(S(2)+ S(3»}1 «I.00-S(I»*(I.00-(S(2)+S(3)))+(I.00-S(I))*(S(2)+S(3)}) 1* Wins by ATV pairing 2 *1; 1:(1.00-S(I»*(S(2)+S(3»1 «I.00-S(1»*(I.00-(S(2) +S(3))) + (1.00-S(I»*(S(2) + S(3») 1* Wins by FATV in pairing 2 *1; 1* Total number paired comparisons: pairing 3 *1; COHORT=5 2:(I.00-S(I»*(I.00-(S(2)+S(3»)/«I.00-S(I»*(1.00-(S(2)+S(3»)+ S(I)*S(2» 1* Wins by ATV in pairing 3 *1; 3:S(I)*S(2)/«I.00-S(1»*(I.00-(S(2)+S(3)))+ S(I)*S(2» 1* Wins by FATW in pairing 3 *1; COHORT=8 1* Total number paired comparisons: pairing 4 *1; 6:S(I)*(I.00-S(2»/(S(I)*(I.00-S(2»+(I.00-S(I»*(S(2)+ S(3») 1* Wins by ATW in pairing 4 *1; 2:(I.00-S(I»*(S(2)+S(3»/(S(I)*(I.DO-S(2»+(I.00-S(1»*(S(2)+ S(3)}) 1* Wins by FATV in pairing 4 *1; COHORT=8 1* Total number paired comparisons: pairing 5 *1; 5:S(I)*(I.00-S(2»/(S(I)*(I.00-S(2»+S(I)*S(2» 1* Wins by ATW in pairing 5 *1; 3:S(I)*S(2)/(S(I)*(I.00-S(2»+S(1)*S(2» 1* Wins by FATW in pairing 5 *1; COHORT= 8 1* Total number paired comparisons: pairing 6 *1; 3:(I.00-S(I)}*(S(2)+S(3)}/«(1.00-S(I»*(S(2)+S(3»+S(I)*S(2» 1* Wins by FATV in pairing 6 *1; 5:S(I)*S(2)/«I.00-S(1»*(S(2)+S(3»+S(I)*S(2» 1* Wins by FATW in pairing 6 *1; LABELS; S(I)=ATW LEVEL OF SUBSPECIES; S(2)=TREATMENT LEVEL OF FERTn.IZATION; S(3)=INTERACTION TERM; PROC ESTIMATE NAME=A_B_X; INITIAL; S(I)=0.4; S(2)=0.6; S(3)=0.1; CONSTRAINTS; S(3) > -1.0; S(3) < 1.0; PROC ESTIMATE NAME=A_B; INITIAL; S(I)=0.3; S(2)=O.4; CONSTRAINTS; S(3)=0.0; �74 APPENDIX 2-2. Continued. PROC ESTIMATE NAME=B; INITIAL; S(2) =0. 1; CONSTRAINTS; S(I)=0.5; S(3)=0.0; PROC ESTIMATE NAME=A; INITIAL; S(I)=O.25; CONSTRAINTS; S(2)=0.5; S(3)=0.0; PROC ESTIMATE NAME=NULL; INITIAL; S(I)=0.5; CONSTRAINTS; S(I)=S(2); S(I)=S(2); S(3)=O.O; PROCTEST; PROC STOP; < < �7) CHAYI'ER 3 EXPERIMENTAL ESTIMATION OF SAGE GROUSE. FEEDING PREFERENCES INTRODUCTION Sage Grouse forage selectively with respect to topography (Hupp and Braun 1989), sagebrush subspecies (Remington and Braun 1985, Welch et 31. 1991), and chemical characteristics of individual plants (Remington and Braun 1985, Welch et 31. 1988). Forage selection patterns, however, have not been consistent. Sage Grouse in north-central Colorado forage selectively on Wyoming big sagebrush (Artemisia tridentata wyomineensis) and avoid mountain big sagebrush CA. 1. vaseyana) (Remington and Braun 1985, Chapter 1), but Sage Grouse in southern Colorado (Hupp and Braun 1989) and Utah (Welch et 31. 1991) use mountain big sagebrush. Plant chemistry was correlated with forage selection in some cases (Remington and Braun 1985, Welch et 31. 1988) but not others (Hupp 1987, Welch et 31. 1988). The availability of different forages (Welch et 31. 1991) and Sage Grouse physiological adaptation to particular diets (Levey and Karasov 1989) likely are strong components of any explanation for observed inconsistencies in forage selection patterns. I increased the use of Wyoming big sagebrush by Sage Grouse by applying nitrogen fertilizer to plants (Chapter 1), presumably by improving forage quality. �76 Use rates of mountain big sagebrush were not affected, which does not preclude an increase in forage quality when nitrogen availability is increased. < < If Sage Grouse experience with forages of variable availability or predictability is an important determinant of forage selection, then unequal predictability or availability of forages can confound evaluation of forage selectivity. To remove the potential confounding effects of forage availability on feeding preferences, I used captive-reared Sage Grouse to experimentally estimate foraging preferences for 2 sagebrush subspecies. I also tested whether feeding preferences for these subspecies were affected by nitrogen fertilization. METHODS Preference trials I used 8 Sage Grouse in preference trials to estimate the effects of 2 subspecies and 2 levels of nitrogen fertilization (0 or 112 kg-N/ha) on feeding preferences of grouse. Ammonium nitrate (33 % nitrogen) was applied to sagebrush rangeland in North Park, Jackson County, Colorado in a randomized complete block design (Chapter 1) to manipulate foliar chemistry. In winters after the first and second year of growth response by each subspecies, I removed leaves from plants for estimating feeding preferences of grouse. The 4 treatment levels formed from the 2 x 2 factorial were randomly grouped into the 6 possible pairs and presented to each bird in paired comparison (David 1988) preference trials . I used 4 hand-reared birds from eggs obtained from Sage Grouse in North Park to estimate preferences of birds for sagebrush treatments in the first year of �I I fertilizer response. Birds were about 8 months old when testing began. They had been maintained primarily on commercial game bird rations but were also given all 4 sagebrush types to become familiar with experimental treatments. equally available to birds. Treatments were In the second year of fertilizer response I used 2 birds obtained on loan from the University of Wyoming, Laramie captive flock and 2 birds obtained from the wild population in North Park. reared from eggs collected s The Laramie birds were captive- 150 km NE of North Park. Maintenance conditions were similar to those I used except that no attempt was made to provide access to all treatments until several weeks preceding the trials. The 2 North Park birds were captured during February and trained to consume the same ration used to maintain the Laramie birds. All birds were held in 77 x 62 x 161 em (width x height x length) or 74 x 62 x 145 em metabolism cages in an airy, unheated garage. The posterior 1/3 of each cage was covered so that birds could be isolated from disturbance at the front of the cage caused by placement and removal of treatments. Snow was placed in each cage to provide a water source as temperatures were mostly below freezing. Trials conducted in year 1 were run under a controlled photoperiod of 14: 10, dark:light hrs: I did not control photoperiod in year 2. Preference trials involved simultaneous presentation of sagebrush leaves in 2 400-ml beakers to each bird, allowing it to feed for 60 min, and estimating the fresh mass intake to the nearest 0.1 g of each treatment in the paired comparison. Positions of treatments on the left or right side of each cage were randomized, and positions were switched on the subsequent replications of each experiment. Mass changes of �78 control sagebrush leaves were used to estimate moisture loss from sagebrush during each trial. Birds were fasted overnight prior to each trial, and trials commenced in the first hour after sunrise. Simultaneous to the intake-based preference trials, I observed onset of feeding by birds. At the start of each replication, I retreated from view of the birds and recorded the first beaker into which each bird approached and initiated feeding. I defined the initiation of feeding as whenever a bird's beak:broke the plane formed by the top of the beaker. I scored treatments used first as preferred (1) and the beakers not used first as not preferred (0) in the paired comparison. If a bird did not initiate feeding within 15 min both treatments were scored as not preferred. I also scored the intake assays as 1 or 0 on the basis of relative intakes so that feeding initiation patterns could be compared with feeding preferences over longer periods. I used the behavioral assay only with sagebrush in the first year of response to fertilization. Statistical analyses Paired comparison experiments to estimate feeding preference rankings and to evaluate factors governing preferences were analyzed as balanced incomplete blocks with main and subplot structure. Birds (ID) and pairings of sagebrush treatments (pairing) formed main plot effects that were tested against the main plot error term formed by the ID x Pairing effect. Each pairing formed an incomplete block having 2 of 4 possible treatments. Sagebrush treatment was the subplot effect that I partitioned into 3 single degree of freedom contrasts for subspecies, fertilizer, and subspecies x fertilizer interaction., These data were subjected to a rank-transformation (Conover and Iman 1981) due to heterogeneous variances of sagebrush treatment response �I ';j groups and analyzed in a generalized linear model framework (SAS Institute, Inc. 1988:549-640). For each of the 6 pairings of treatments I also tested the hypothesis that intakes were equal by computing Bonferroni paired 1 tests. The behavioral assay for forage preference consisted of independent Bernoulli trials where a bird was scored as preferring (1) or not preferring (0) treatments in paired comparisons. In my paired comparison experiments I tallied the number of times sagebrush treatment i was chosen over treatment j in the 6 possible pairings of 4 treatments. Treatment positions in cages were randomized and reversed in 2 replications for each bird, so the effect of replication was removed by design. assumed there were no nonrandom effects due to individual birds. I I used Bradley-Terry (BT) models to estimate the preference probability ('J') ranking for each treatment from paired comparison preference trials (Bradley and Terry 1952), and tested for factorial treatment effects with a reparameterized BT model (Chapter 2). Preference probabilities estimate the probability of treatments being selected in a simultaneous test of all treatments. o - 1 and I:Tj = Thus, their parameter values fall into the interval 1. I obtained numerical solutions of BT model parameters (1t) and constructed likelihood ratio x: tests of nested submodels using program SURVIV (White 1983). Program SURVIV computed asymptotic 95 % confidence intervals (CI) for preference rankings as T ± 1.96sE. �80 RESULTS < < Bradley-Terry model analysis The initial treatment selection by grouse making paired comparisons among sagebrush treatments was a random process Behavior scores). ~3 = 4.746, f = .191, Fig. 3-1: The expected value for .•. under Ho: was 0.25, and only FATV had a T with an asymptotic 95% CI that did not cover 0.25. 60 min for ATV and FATV were not different from 0 ~ Preference probabilities after < .05), and ATW and FATW were selected significantly more than expected by chance (Fig. 3-1). Estimates for ATV and FA TV were 0 because these treatments did not receive nonzero scores when paired against ATW or FA TW. Fertilizer had no effect on preference ~ = .315, Fig. 3-1), despite FATW having a significantly higher individual preference probability compared to ATW (Fig. 3-1). Although Fig. 3-1 indicates a subspecies x fertilizer interaction effect among treatments, FA TV was favored over ATV at the same rate as FA TW over ATW. The factorial BT model has a multiplicative combination of subspecies and fertilizer effects rather than an additive one (Chapter 2), thus the apparent interaction was caused by the estimate of the fertilizer effect being multiplied by the near-zero value of the estimate of the effect of ATV subspecies status on treatment preference. Power to detect a significant subspecies x fertilizer effect of the observed magnitude was 7%. Behavioral assay estimates differed from preference probabilities estimated from the intake assays ~3 = 19.688, f < .001). Replication had no effect on preference probability estimates ~3 = 1.081, f = .782), so use of the basic BT model without replication effects was justified. Power to detect replication effects was low (12 %) �81 0::: 0 ~ I w CD ATV ATW FATV FATW • I HO: 1f = SOURCE SSP FERT S*F 0.150 0.150 0.678 SOURCE SSP FERT S*F p <0.001 0.315 1.000 P 0.25 ATV ~ « ATW rz FATV FATW w t-e-l 0.0 0.4 0.2 0.6 0.8 1.0 PROBABILITY PREFERENCE Fig. 3-1. Sage grouse preference probabilities (7 and 95% CI) for sagebrush in the first year after treatment. model analysis. (/) w 0:: 0 ATV I-e--I <..> ATW w ~ ~ FATV (/) Main effects summary is from a factorial Bradley-Terry P SOURCE SSP <0.001 FERT 0.215 S*F 0.918 • • z FATW HO: 1f 0.0 0.2 = 0.4 PREFERENCE 0.25 0.6 0.8 1.0 PROBABILITY Fig. 3-2. Sage grouse preference probabilities (?f- and 95 % CI) for sagebrush in the second year after treatment. model analysis. Main effects summary is from a factorial Bradley-Terry �82 for effects of this size. < < In the second year of foliar response to fertilization the preference probabilities for ATV and FATV increased over the first year, but both were significantly lower than 0.25 (Fig. 3-2). The preference probability for FATW was significantly greater than 0.25, and overall, a large subspecies effect persisted (Fig. 3-2, £ < .001). Fertilizer did not cause an overall increase in preferences for sagebrush ~ = .215). General linear model analysis Consumption (g fresh matter) of treatments by birds varied significantly in the paired comparison intake trials (Table 3-1). Subspecies status had a large effect on intake ~ < .(01), as birds consumed ATW and FATW at about 5 - 10 times the ATV subspecies (Fig. 3-3). No subspecies x fertilization interaction was detected, thus fertilizer affected the intake of both subspecies ~ = .043). Consumption patterns by grouse in the second year of fertilizer response were similar to those observed in the first year (Fig. 3-3, Table 3-2) except that fertilizer no longer influenced intake ~ = .152). Power to detect this effect was about 0.29 and would not have been improved substantially by increasing the number of birds used by a factor of 5. Experimental error of this experiment (CV = 33.8%) was larger than in the first year (CV = 22.4%), however, if experimental errors in the second year trials were of the same magnitude as in the first year power to detect this effect would only increase to 57%. I partitioned the 3 df associated with birds to include a contrast of Colorado vs. Wyoming birds and found that bird source did not affect the total amount consumed during trials ~ = .644). �Table 3-1. Factors affecting consumption of sagebrush during preference trials in first year of sagebrush response to fertilization. Source of variation df £>1: 1: MS Pairing 5 292.94 6.90 ID 3 466.17 10.99 <.001 15 42.43 1.40 .232 3 2106.06 69.67 <.001 Subspecies 1 6132.78 202.88 <.001 Fertilizer 1 140.28 4.64 .043 Subspecies x fertilizer 1 45.13 1.49 .252 21 30.23 Pairing x ID (main plot error) Treatment Subplot error YEAR 1 .002 TREATMENT YEAR 2 MEAN (SE) QTI 0.151 3 0.8 (004) ) '" FATV QIJ 9 [J 1 ) -,~ <y ,7 r-, 0 0 0 2.3 (0.7) ) ? r") -, 0.144 FATV 0.640 0 0 I.() ci 0 ~ ~ N 0 0 ~ FATW 3.9 (0.7) D:J 1 ) 0.558 FATW 8.3 ( 1.1) Fag. 3-3. Average intakes of sagebrush (g fresh mass) during paired comparison preference trials. Values along arrows are probabilities of treatments within paired comparisons being the same. < < �84 Table 3-2. Factors affecting consumption of sagebrush during preference trials in second year of sagebrush response to fertilization. Source of variation df F MS £>F Pairing 5 254.62 2.82 .055 ID 3 192.88 2.14 .138 1 20.02 0.22 .644 15 90.24 1.32 .274 3 1336.36 19.54 <.001 Subspecies 1 3773.63 55.18 <.001 Fertilizer 1 150.95 2.21 .152 Subspecies x fertilizer 1 84.50 1.24 .279 21 68.39 Bird source Pairing x ID (main plot error) Treatment Subplot error Paired Bonferroni 1 test analyses were considerably less efficient than the balanced incomplete block analysis (Fig. 3-3). Subspecies effects were detectable in year 1 but not in year 2 when experiment-wise Type I error rate was controlled with the Bonferroni inequality. No effect of fertilizer could be detected with this analysis. DISCUSSION I gave captive-reared Sage Grouse equal access to all 4 treatments tested and allowed them to establish feeding preferences without the potentially confounding influences of variable availability or predictability. These birds showed the same, strong feeding preference for Wyoming big sagebrush and against mountain big sagebrush as observed in field studies in North Park, Colorado (Remington and Braun , < �1985, Chapter 1). Preference for Wyoming big sagebrush does not, however, mean mountain big sagebrush was nutritionally inadequate for maintaining Sage Grouse. I also make no claim that Wyoming big sagebrush is universally preferred over mountain big sagebrush and agree with Welch et ale (1988) that previous field studies of Sage Grouse foraging ecology have not adequately accounted for availability differences (Remington and Braun 1985). I compared equal numbers of Wyoming and mountain big sagebrush plants (Chapter 1) and experimentally estimated feeding preferences where availability was equal (this study). In each case, Wyoming big sagebrush was favored over mountain big sagebrush. Sagebrush chemistry can vary according to species (Kelsey and Shafizadeh 1979), subspecies and accessions (Welch and McArthur 1979,1981), and among plants within a feeding site (Remington and Braun 1985, Welch et ale 1988) making formulation of a general explanation of forage selectivity patterns difficult without experimental evidence across taxonomic units and geography. Nitrogen availability for sagebrush had a positive influence on my measures of forage preference. Birds consumed more sagebrush foliage of both subspecies when it was fertilized than when it was not. An effect of fertilization of forage use was not detected in field studies of mountain big sagebrush (Chapter 1), which may have be due to lag effects between habitat manipulations and population responses (Wiens et ale 1986). Birds also may avoid switching among sagebrush taxa if physiological adaptation to a different diet imposes transitory metabolic costs (Levey and Karasov 1989). These costs would discourage use of less available or predictable forages. < v �86 The initial selection of sagebrush by grouse was a random process, but after sampling, birds strongly preferred Wyoming big sagebrush over mountain big sagebrush. In my experiments, several potential edaphic and morphological cues were eliminated by presenting sagebrush as leaves in beakers. Without these cues birds could not correctly choose the "best" food without random sampling. Even with all morphological and edaphic cues available to birds it is possible that grouse may still sample plants within a site to locate individual plants of acceptable quality. This aspect of Sage Grouse foraging ecology has not received rigorous attention as variation among plants within plots or sites have been pooled into between-plot variation for analyses (Remington and Braun 1985, Hupp 1987) or replication of feeding sites has been inadequate (Welch et al. 1988). Better understanding of the dynamics of plant characteristics and Sage Grouse herbivory could be obtained with studies that have nested sampling structures so that hierarchial analyses of plant chemistry and herbivory can be incorporated into models of forage selection. Preference studies can be made more powerful relative to paired 1 test analyses by using paired comparison experiments that have a balanced incomplete block design. Qualitative responses in preference bioassays also should be considered when planning preference/avoidance studies. Bradley-Terry model analysis allows one-way and factorial effects analysis of treatments tested in paired comparison experiments (Chapter 2). <' �87 LITERATURE CITED Bradley, R. A., and M. E. Terry. 1952. Rank analysis of incomplete block designs. 1. The method of paired comparisons. Biometrics 16:178-188. Conover, W. J., and R. L. Iman. 1981. Rank transformations as a bridge between parametric and nonparametric statistics. The American Statistician 35: 124-128. David, H. A. 1988. The method of paired comparisons. Charles Griffm, London, England. 188pp. Hupp, J. W. 1987. Sage Grouse resource exploitation and endogenous reserves in Colorado. Ph.D. Thesis, Colorado State University, Fort Collins. 73pp. Hupp, J. W., and C. E. Braun. 1989. Topographic distribution of Sage Grouse foraging in winter. Journal of Wildlife Management 53:823-829. Kelsey, R. G., and F. Shafizadeh. 1979. Sesquiterpene lactones and systematics of the genus Artemisia. Phytochemistry 18:1591-1611. Levey, D. J., and W. H. Karasov. 1989. Digestive responses of temperate birds switched to fruit or insect diets. Auk 106:675-686. Remington, T. E., and C. E. Braun. 1985. Sage Grouse food selection in winter, North Park, Colorado. Journal of Wildlife Management 49: 1055-1061. SAS Institute, Inc. 1988. SASISTA'J"1' user's guide, release 6.03 edition. SAS Institute, Cary, North Carolina, USA. 1028pp. Welch, B. L., and E. D. McArthur. 1979. Variation in winter levels of crude protein among Artemisia tridentata subspecies grown in a uniform garden. Journal of Range Management 32:467-469. �88 Welch, B. L., and E. D. McArthur. 1981. Variation of monoterpenoid content among subspecies and accessions of Artemisia tridentata grown in a uniform garden. Journal of Range Management 34:380-384. Welch, B. L., J. C. Pederson, and R. L. Rodriguez. 1988. Selection of big sagebrush by Sage Grouse. Great Basin Naturalist 48:274-279. Welch, B. L., F. J. Wagstaff, and J. A. Roberson. 1991. Preference of wintering Sage Grouse for big sagebrush. Journal of Range Management 44:462-465. White, G. C. 1983. Numerical estimation of survival rates from band-recovery and biotelemetry data. Journal of Wildlife Management 47:716-728. Wiens, J. A., J. T. Rotenberry, and B. Van Home. 1986. A lesson in the limitations of field experiments: shrubsteppe birds and habitat alteration. Ecology 67:365-376. �CHAPTER 4 EFFECT OF NITROGEN FERTILIZATION ON mE NUTRITIONAL QUALITY OF BIG SAGEBRUSH FOR SAGE GROUSE INTRODUCTION The Sage Grouse, Centrocercus urwhasianus, is a seasonal dietary specialist on sagebrush foliage, Artemisia spp. (patterson 1952). Sage Grouse subsist as generalist omnivores when insects and forbs are available but switch to a diet consisting almost totally of sagebrush foliage during other months. The specific sagebrush taxa exploited varies at landscape scales as sagebrush species composition changes across the range of the Sage Grouse. At smaller scales, Sage Grouse sometimes make selective use of sagebrush subspecies and plants (Remington and Braun 1985, Welch et al. 1991). One explanation advanced to explain observed forage selectivity of Sage Grouse in north-central Colorado was an interplay between plant primary and secondary chemistry (Remington and Braun 1985). If Sage Grouse populations are limited by metabolizable energy or nitrogen of sagebrush, the potential exists to manipulate plant chemistry and thus improve habitat quality for Sage Grouse. Remington and Braun (1985) proposed applying nitrogen fertilization to sagebrush to alter resources available to sagebrush (Bryant et al. 1983) so that �90 nutritional quality is increased. They assumed that unused plants and subspecies were not nutritionally adequate and that fertilization would increase plant quality. With improved quality, use of formerly palatable plants and subspecies should be increased. Increased dietary nitrogen has produced an increase in several fitness correlates of Ruffed Grouse @onasa umbellus) (Beckerton and Middleton 1982) and Red Grouse lLa&<wus la&wus scoticus) (Miller et ale 1970). In this way the amount and quality of foraging habitat could be increased and provide a tool for habitat remediation, enhancement, or mitigation. In other work I showed that nitrogen fertilization increased the use of Wyoming big sagebrush, Artemisia tridentata ~omingensis (ATW) under field conditions (Chapter 1). On that study area, ATW was the winter forage most likely to be selected, whereas mountain big sagebrush, A. 1. vaseyana (ATV) was avoided (Remington and Braun 1985). In laboratory trials I also demonstrated that consumption of both ATW and ATV could be increased with fertilization (Chapter 3). Here I test whether nitrogen fertilization affects the availability of energy and nitrogen in these forages for Sage Grouse. METHODS Feedin& trials I used 8 female Sage Grouse captured from a wild population in North Park, Jackson County, Colorado to experimentally estimate forage digestibility. I captured birds during February and March and held them in metabolism cages (77 x 62 x 161 cm or 74 x 62 x 145 em) in an airy, unheated garage. The posterior �91 1A of each cage was covered so that birds could be isolated from disturbance at the front of the cage caused by placement and removal of treatments. Snow was placed in each cage to provide a water source as temperatures were mostly below freezing. Photoperiod was set at 14:10, dark:light hrs. I manipulated foliar chemistry of ATV and ATW, the 2 sagebrush subspecies that predominate in the areas I captured grouse. By applying 112 kg-N/ha to ATV and ATW plants I produced 4 treatments (ATV, FATV, ATW, and FA TW) having a 2 x 2 factorial structure for the main effects subspecies (SSP) and fertilization (FERT). Foliage was collected in the winter following the first growing season after nitrogen application and promptly tested in bioassay. I collected foliage from sites on or 'near Sage Grouse feeding sites. Fertilization produced increased nitrogen levels in foliage (fable 4-1), but not as much as in more extensive field testing (Chapter 1). I used a modification of Sibbald's (1979) true metabolizable energy (TME) assay rather than classical digestion trials, because preliminary work indicated that wild birds would not consume diets at maintenance levels. The TME assay has been previosuly used on wild birds (Jorde and Owen 1988). Trials were conducted by presenting to birds a single treatment at a time for 2 d and collecting all excreta. After 2 d, birds were fasted for another 1 d to collect any food remaining in the gut (Sibbald 1979). Rather than controlling intake to 3-4 pre-selected levels I allowed birds to feed aQ libitum and used the observed variation in intake to explore relationships among ingested and retained nutrients. At the same time I estimated palatability of different forages from amounts consumed. I weighed each bird at the start and finish of each trial to monitor body mass dynamics. �92 Table 4-1. Characteristics of sagebrush foliage fed to captive sage grouse. Nitrogen (% DM) Gross energy (kJ/g-DM) NDF (% DM) ADF (% DM) Subspecies Fertilization ATV No 1.27 23.04 27.1 17.3 Yes 1.40 23.21 26.6 16.1 No 1.67 22.89 31.1 19.1 Yes 2.03 23.03 31.1 19.1 ATW The experimental design was 2-4 x 4 latin squares with assignments randomized by row and column separately for each latin square. I presented treatments as whole stems, because most wild birds could not be conditioned to feed upon picked leaves. sunrise. Sagebrush stems and foliage were added to cages at about Sagebrush also was placed on top of cages in the morning and weighed at night to estimate water loss during the day. After the evening feeding period sagebrush was removed from the cages and weighed. collected, weighed, and discarded. Spilled sagebrush was Diurnal fecal droppings were collected and stored overnight in resealable plastic bags. The following morning fecal droppings were collected and added to those already stored. Cecal droppings were placed into separate plastic bags. Droppings were frozen until processed by freeze-drying and grinding in a mortar and pestle. Dry matter content of foliage and grouse droppings was determined after drying overnight at 100°C. Samples were ashed overnight at 500°C to determine organic matter and ash content. energy (Horwitz 1980) of samples were measured. Kjeldahl nitrogen and gross �Statistical analysis I estimated effects of subspecies (SSP) and fertilization (FERT) on daily intakes of dry matter, energy, and nitrogen with analysis of variance (pRDC GLM; SAS Institute, Inc. 1988). I used analysis of covariance (ANCDV A) procedures to test hypotheses about effects of subspecies and fertilization on relationships between dry matter intake and grouse body mass dynamics (SAS Institute, Inc. 1988). I report precision estimates for parameters as ± ISE. Apparent metabolizable energy (AME) intake (kJ/g dry matter intake) and assimilation coefficients (AMEC) are traditional measures for summarizing nutritional quality of avian forages. They are the appropriate measures when test animals are fed at maintenance levels and when predicting forage intake requirements from existence metabolism. TME is appropriate for estimating forage intake requirements to meet energy requirements calculated as a multiple of basal metabolism (Miller and Reinecke 1986). AMEC is estimated by (4.1) where Qi = g DM intake, Qe = g DM excreted, GEi = kJ/g DM of food, and G~ = kJ/g DM of all excrement. AME and AMEC are not independent of level of intake, because they do not include excretion of fecal metabolic energy (FF,J or urinary endogenous energy ('lTEe)as excretory energy that is not immediately of food origin (Miller and Reinecke 1986). AMEC values are related to true metabolizable energy coefficients (TMEC) by -£FEm + UEJ/(Q(GEJ (Sibbald 1979, Miller and Reinecke 1986). The value for �94 £FEm + UEJ is constant under standard conditions and has been estimated from ( Qc'GEe measured from fasting birds (Sibbald 1976, 1979). Although the size of this bias is only about -0.03 when birds are fed at maintenance (Karasov 1990), AMEC estimates become progressively more biased at low intake rates. Any tests for differences among AMEC for different forages therefore are also biased by level of intake. TMEC and TME are unbiased by level of intake (Sibbald 1979, Miller and Reinecke 1986). TMEC as a fraction of intake energy is estimated by TMEC • GE.oQ. - (GE oQ - [FE + UE]) J e J GEj e -a, me. (4.2) Rearrangement of (4.2) gives a linear model, for estimating TMEC from data normally collected during digestion trials. This model is more general than simple ratio estimators, emphasizes the relationship among the intake and retention of nutrients, and provides a familiar framework for displaying relationships and testing underlying assumptions for valid inference (Sokal and Rohlf 1981). By combining terms, a general model for any nutrient (v) having an endogenous or urinary loss component, e.g., energy, nitrogen and dry matter, has the form . a..-t :«,, AR • where: AR. = apparent retained amount of nutrient, v, a. = true metabolizability or digestibility coefficient for v J. = amount of v ingested, and (4.4) ( �'.:1:) a, = fecal metabolic plus urinary endogenous contribution to AR~. < This model can be coupled with dummy variables (ANCOVA) to test hypotheses about treatment effects on 0 and a, e.g., TMEC and [FEm + UEJ, respectively. I used model (4.4) in an ANCOVA to estimate 0, and a, for fertilized and unfertilized ATV and ATW foliage. Dummy variables in ANCOVA models were SSP, FERT, and individual birds used in the trials (ID). I examined the residuals from all models to ascertain their compliance with assumed normality and homogeneity of error variances. No information is lost by using (4.4) since apparent use efficiency coefficients and 0, are related by Apparent use efficiency of J! •• (4.5) 0, - ;' . , RESULTS I used 8 birds during the experiment, but only 6 completed testing on all treatments thereby reducing the design to randomized complete blocks. I estimated treatment effects on palatability of sagebrush by measuring daily foliage ingestion rates. Daily intakes of dry matter and energy were not strongly affected by sagebrush subspecies or fertilization status (Table 4-2). Birds consumed more fertilized ATW than unfertilized ATW ~ = .059), which also caused nitrogen intake on this diet to be nearly 3 x greater than for other diets (Table 4-2). Nutrient intakes for fertilized and unfertilized ATV were similar ~ > .6). < �\0 0\ Table 4-2. Effects of big sagebrush subspecies (SSP) and fertilization (FERl) status on intake of dry matter, . energy and nitrogen by 6 captive sage grouse. Intake Dry matter (g/d): Subspecies Fertilization ATV No ATW Energy (kJ/d) Nitrogen (g/d) SB X SB X 22.7 5.2 524 119 0.29 0.07 Yes 17.1 8.0 397 186 0.24 0.11 No 14.9 6.6 341 151 0.25 0.11 Yes 36.7 9.4 846 215 0.75 0.19 E f>E E X SB ANOVA f>E f>E df E ID 5 0.91 .502 0.91 .502 1.03 .436 SSP 1 0.61 .446 0.59 .455 3.36 .087 FERT 1 1.15 .301 1.18 .295 3.12 .098 SSP"'FERT 1 3.31 .089 3.29 .090 4.62 .048 Source Error 15 �'71 Table 4-3. Effects of sagebrush subspecies (SSP) and fertilization (FERT) on sage grouse body mass dynamics (g fresh mass lost or gained per day). £>E E Source df Intake 1 963.9 7.29 .013 SSP 1 442.2 3.35 .078 Intake*SSP 1 1342.9 10.16 .004 FERT 1 <0.1 <0.01 .988 Intake*FERT 1 7.6 0.06 .812 SSP*FERT 1 130.9 0.99 .324 Intake*SSP*FERT 1 38.0 0.29 .597 24 132.1 Error MS Intakes of sagebrush foliage were below maintenance levels, and Sage Grouse lost an average of about 2% of body mass per d. Dry matter intake ~ sagebrush subspecies ~ = = .013) and .004) both affected body mass dynamics of birds (Table 4-3). Conversion efficiency of dry matter intake to body mass for ATV-FATV was not different from 0 ~ > 0.8, Fig. 4-1), and birds lost an average of 31.4 g/d while on ATV-FATI. treatments regardless of intake (Fig. 4-1). When only ATW-FATW treatments were considered, the relationship between mass balance and intake was Y = -49.6 + 0.70·?, ~ < .001, r = 0.597). Predicted maintenance intake was 70.8 g-DM/d. Fertilization did not affect the rate of metabolizable energy capture ~ = .948) from intake energy, but TMECs differed ~ The TMECs were 0.414 + 0.063 and 0.561 = .013) between subspecies (Table 4-4). + 0.047 for ATV and ATW subspecies, �98 '. < 20 ATV -e-,--.... ATW • -0 <, 01 0 Y - -O.03x Y - O.70x - 49.6 • "-"" w - 31.4 • • • u ~ -20 _.J « CD (f) (f) « ~ -40 • • • - 60 '--"-- o "'-...I.._,____''' 20 40 60 80 DRY MATTER INTAKE (g/d) o Fig. 4-1. Sage grouse body mass dynamics in relation to daily dry matter intake of 2 big sagebrush subspecies. respectively. Metabolizable energy was extracted from dry matter at 9.6 for ATV and 12.9 ± + 1.4 kJ/g 1.1 kJ/g for ATW. For birds consuming sagebrush foliage at the predicted maintenance rate, estimated TME intakes were 609, 769, 1050, and 888 kJ/d for ATV, FATV, ATW, and FATW, respectively. I estimated £FEm+ UEJ to be 71.6 fertilization (f CEs.ll = ± 30.8 kJ/d for all levels of subspecies (f = .118) and .390). Estimates of £FEm+ UEJ also did not differ among birds = 1.34, ~ = .316). Predicted AME intakes were calculated as TME - £FEm+ UEJ. �Table 4-4. Effects of big sagebrush subspecies (SSP) and fertilization (FERT) status on digestibility (6) of dry matter, energy and nitrogen by 6 captive sage grouse. Digestibility coefficients Dry matter A Nitrogen A 6 SE 6 SE 0.077 0.37 0.080 -1.49 0.994 0.47 0.074 0.47 0.076 0.14 0.858 No 0.62 0.088 0.65 0.091 -0.62 0.858 Yes 0.55 0.046 0.54 0.048 0.08 0.371 E f>E E 6 Subspecies Fertilization ATV No 0.35 Yes ATW Energy A SE ANCOVA E f>E Source df Intake 1 102.85 <.001 99.44 Intake"'SSP 1 7.85 .Oll 7.52 Intake"'FERT 1 0.15 .707 Intake"'SSP"'FERT 1 2.37 .140 Error <0.01 2.39 <.001 f>E 0.77 .391 .013 0.33 .574 .948 2.76 .113 .139 0.46 .505 19 <.C \.( �100 Birds did not consume enough forage to maintain a positive nitrogen balance (intake nitrogen - excretory nitrogen) on any diet. Nitrogen balance (g/d) was -1.2 ± 0.3 for ATV, -0.7 for FATW. ± 0.1 for FATV, -1.1 + 0.8 for ATW, and -0.8 ± 0.4 Nitrogen balance was not influenced by subspecies ~ = .999) or fertilization ~ = .183). Although total nitrogen intake was 3 x greater for FATW than for ATW, nitrogen balance was not affected ~ = .430). nitrogen (g/d) was a function of intake nitrogen ~ = .018, Total excretory f = 0.228), but amounts of metabolized nitrogen were not related to intake nitrogen (Table 4-4, £ = .391). Dry matter digestibility coefficients mirrored TMECs (Table 4-4). Digestibility was affected by subspecies ~ = .011) but not fertilization ~ = .707). Combined fecal metabolic plus endogenous dry matter excretion averaged 4.9 1.3 gld and did not differ among birds <Es.11 = 1.26, f = ± .346). DISCUSSION This study demonstrated that Sage Grouse forage selectivity observed in field studies (Remington and Braun 1985, Chapter 1) was correlated with several measures of food quality. Although fertilization of ATW in the field produced significantly increased use by grouse (Chapter 1) and increased consumption rates for both subspecies in laboratory trials, fertilization had no measureable effect on forage quality. The rate of metabolizable energy capture from foliage was greater for Wyoming big sagebrush, the forage selected in the field by the population of birds I sampled, than for mountain big sagebrush. Predicted metabolizable energy intake of ATW at maintenance was 913 kJ/d and provided 84 - 94% of predicted field �lUJ.. metabolic rate for non-passerines the size of female Sage Grouse (971 - 1084 kJ/d, Nagy 1987). Mountain big sagebrush at the same level of dry matter intake provided 63 - 70 % of predicted field metabolic rate. Predicted existence metabolism for the birds I tested should have been 719 - 793 kJ/d (Andreev 1988), which was slightly larger than predicted daily metabolizble energy intake of ATV (681 kJ/d). Birds on ATW diets converted dry matter intake to body mass at an efficiency of 70%, which was significantly greater than for ATV, to further support assertions that quality differences existed among subspecies. My regression of body mass dynamics on dry matter intake explained about the same amount of variation in mass balance (i = 0.597) Red Grouse (i = as did the relationship between ME intake and mass balance for 0.53, Moss and Trenholm 1987). Remington (1990), however, found no relationship between forage intake and body mass dynamics. Sage Grouse have meager endogenous nutrient reserves to exploit during reproduction (Remington and Braun 1988, Hupp and Braun 1989) making dietary sources critical. Variation in nitrogen intake of the magnitude I produced in Sage Grouse significantly enhanced fitness correlates in Ruffed Grouse, e.g., for every 1 % increase in dietary crude protein content, clutch size was increased by 0.7 (Beckerton and Middleton 1982). Nitrogen balance should be achieved at intakes of between 0.5 - 0.6 g-N/d (Robbins 1981) or 0.4 - 0.9 g-N/d (Andreev 1988). All treatments contained enough nitrogen to match predicted maintenance nitrogen requirements if consumed at predicted maintenance dry matter intake. Reproductive costs are about 175% of maintenance (Robbins 1981), however, and only ATW and FATW would meet this level. Actual maintenance needs may be higher than predicted, because ,' �102 detoxification metabolism of sagebrush anti-herbivore chemistry may impose energetic and nitrogen costs (Remington 1990). Fertilization effects on sagebrush chemistry should influence metabolizable energy and nitrogen by mitigating detoxification costs, but these effects have been difficult to demonstrate with typical environmental variation in plant secondary chemistry. Remington (1990) measured increased ornithuric acid and ammonium ion excretion by Blue Grouse IDendra~apus obscurus) when benzoic acid was added to Douglas-fir (Psuedotsu~a menziesii) needles but detected no effects on ME, MN, or nitrogen balance. By quadrupling the monoterpene load of Douglas-fir he caused a significant reduction in ME and nitrogen balance, but these parameters were not affected by a doubling of dietary monoterpenes. ME showed no linear trend with level of monoterpene intake. The measured reduction of ME and nitrogen balance was attributed to increased contributions of ammonium and glucuronic acid nitrogen to excretory nitrogen at the highest levels of monoterpene intake. Although total nitrogen excretion may have been increased due to detoxification metabolism, this was not reported. By introducing additional explanatory variables into linear models additional variation in dependent variables can be explained and added insight gained if these terms represent ecological processes. The energy excreted for each g of nitrogen retention or loss is potentially an important determinant of forage quality (Remington 1990), so rather than assuming a constant value, this parameter can be estimated from digestion trial data. The linear model, ,< �lUj estimated 0 (AMECN) for ATV and ATW as 0.42 and 0.56, respectively (f = 0.88). The coefficient, "I, was 37.6 kJ/g N balance did not differ by subspecies even though the ATV diet should have more anti-herbivore compounds (Remington and Braun 1985). Karasov (1990) presented a non-linear, mechanistic model for predicting apparent MEC that has an equivalent linear form similar to (4.6). from (4.6) in the adjustment to zero nitrogen retention. The difference The amount of retained nitrogen is multiplied by a constant, 34.5 kJ/g N, that is essentially the same as values used in conventional estimates of nitrogen-corrected energy (~, apparent metabolizable Sibbald 1979) and the one I estimated. I used linear models to estimate the rates of nutrient capture by Sage Grouse, rather than estimated ratios of retained and ingested nutrients, e.g., AMB. Had I constructed hypothesis tests about apparent assimilation coefficients the tests would have been biased by level of intake. The difference between dry matter digestibility of ATW and ATV at observed dry matter intakes was 36 % larger than if both estimates had been made at maintenance (Fig. 4-2). By using a linear model I tested whether endogenous dry matter excretion and digestibility were affected by treatments and transformed the primary test of interest from one of a difference in the elevation of 2 curves to a test of slopes (Fig. 4-2). The latter test is independent of intake. Other models can be formulated to aid understanding and analysis in forage digestibility studies. For example, the effect of ingesting putative anti-herbivory compounds on metabolizable energy could be estimated by substituting g of the �104 ,, __.- . 0.60 ,....-----------------, ATV ATW 0.40 (:) OBSERVED ?7~~ /~ ::E (:) t- Z 0.20 w a::: t ~/ -c MAINTENANCE INTAKE ," , Q.. Q.. I I I I -c 0.00 .,__-+-;.-: ----------------4 -0.20 50 ---. "'0 40 <, 0\ t- '-" ::E w (:) Z »: 30 ,;' 0::: -c Q.. Q.. -c (:) w 20 OBSERVED INTAKES 10 ~ Z ~ w a::: ;,' """"""".. /" .,1/(" t " MAINTENANCE INTAKE ... ,..,../' ' " 0 0 20 40 60 80 100 INTAKE (g/ d) Fig. 4-2. Relationships among apparent dry matter digestibility (DMD), apparent retained dry matter (DM), and DM intake under linear and nonlinear model formulations. �lU) compound ingested for nitrogen balance. If anti-herbivory compounds exert a net negative effect on bioenergetics, the rate coefficient would be significantly < 0 and should estimate detoxification costs. There are several advantages to analyzing digestion trial data with mechanistic models over simple ratio estimators: 1) because they are mechanistic, they promote rigorous estimation and testing of effects on ecological or physiological processes, 2) the estimation and testing theory is well-developed with numerous supporting software packages, and 3) plots provide useful summaries of relationships among dependent and independent variables and may provide insight into whether assumptions are being met. Inference from any model is limited by the validity of attendant assumptions regarding their use. For the linear models I described the assumptions are essentially those of linear least-squares regression. I observed few problems with homogeneity or normality of errors in residual plots from models having reasonable fits (f > 0.80) to the data. Measurement errors in quantities of nutrients. ingested are controllable and should be small relative to experimental errors in dependent variables. When other explanatory variables, such as nitrogen balance, are added measurement errors could cause precision estimates to be biased. processes that are modeled may in fact be nonlinear. Finally, ecological Adequate nonlinear models may be formulated that include dummy variables for hypothesis testing. Fertilization significantly increased the potential for Sage Grouse to ingest nitrogen at rates shown to have positive effects on fitness. Measurement of an effect on the availability of nutrients was problematic. The birds I tested were adapted to ATW, which is qualitatively and quantitatively different from ATV. Use efficiency < < �106 of nutrients in ATV may have improved over time (Levey and Karasov 1989) as Sage Grouse physiology adapted to a qualitatively different diet. The effects of diet switching on use efficiency could be tested by estimating use efficiencies with birds from populations that are physiologically adapted to different diets and then switching diets in a cross-over experiment. Digestibility trials would need to be conducted for longer than usual for avian studies to measure rate of physiological adaptation. One may argue that birds in negative energy and nitrogen balance do not provide reasonable models for free-ranging birds consuming the same forage, yet dry matter digestibility and metabolizability energy estimates were not unusual for grouse (Karasov 1990). Variation in bird performance certainly contributed to my failure to detect fertilization effects on nitrogen balance when inter-treatment variation in nitrogen intake varied 3-fold. Starvation causes accelerated sloughing of gut mucosa (Bayer et al. 1981) and by-products of protein catabolism likely confounded treatment effects. Both processes add to fecal metabolic and urinary nitrogen, part of which is recycled to the ceca and rapidly decomposed by cecal microbes (Mortensen and Tindall 1981). Cecal recycling may spare nitrogen from excretory processes (Mortensen and Tindall 1984) and may explain why I found only a weak relationship between nitrogen intake and excretory nitrogen and no relationship between intake itrogen and nitrogen balance. <' �10i LITERATURE CITED Andreev, A. V. 1988. Ecological energetics of Palaearctic Tetraonidae in relation to chemical composition and digestibility of their diets. Canadian Journal of Zoology 66: 1382-1388. Bayer, R. C., J. H. Rittenberg, F. H. Bird, and C. B. Chawa. 1981. Influences of short term fasting on chicken alimentary canal mucosa. Poultry Science 60: 1293-1302. Beckerton, P. R., and A. L. A. Middleton. 1982. Effects of dietary protein levels on Ruffed Grouse reproduction. Journal of Wildlife Management 46:569-579. Bryant, J. P., F. S. Chapin, m, and D. R. Klein. 1983. Carbon/nutrient balance of boreal plants in relation to vertebrate herbivory. Oikos 40:357-368. Hupp, J. W., and C. E. Braun. 1989. Endogenous reserves of adult male Sage Grouse during courtship. Condor 91:266-271. Jorde, D. G., and R. B. Owen. 1988. Efficiency of nutrient use by American Black Ducks. Journal of Wildlife Management 52:209-214. Karasov, W. H. 1990. Digestion in birds: chemical and physiological determinants and ecological implications. Studies in Avian Biology 13:391-415. Levey, D. J., and W. H. Karasov. 1989. Digestive responses of temperate birds switched to fruit or insect diets. Auk 106:675-686. Miller, G. R., A. Watson, and D. Jenkins. 1970. Response of Red Grouse populations to experimental improvement of their food. Pages 323-335 in A. Watson, editor. Animal populations in relation to their food resources. British �108 Ecological Society Symposium 10. Blackwell Scientific Publ., Oxford and Edinburgh, England. Miller, M. R., and K. J. Reinecke. 1986. Proper expression of metabolizable energy in avian energetics. Condor 86:396-400. Mortensen, A., and A. R. Tindall. 1981. Caecal decomposition of uric acid in captive and free ranging Willow Ptarmigan (Lae;qpuslae;Oj)uslae;opu~). Acta Physiologica Scandinavica 111:129-133. Moss, R., and 1. B. Trenholm. 1987. Food intake, digestibility and gut size in Red Grouse. British Poultry Science 28:81-89. Mortensen, A., and A. R. Tindall. 1984. The role of urea in nitrogen excretion and caecal nitrogen metabolism in Willow Ptarmigan. Journal of Comparative Physiology B 155:71-74. Nagy, K. A. 1987. Field metabolic rate and food requirement scaling in mammals and birds. Ecological Monographs 57:111-128. Patterson, R. L. 1952. The Sage Grouse in Wyoming. Sage Books, Denver, Colorado, USA. 341pp. Remington, T. E. 1990. Food selection and nutritional ecology of Blue Grouse during winter. Ph.D. dissertation. University of Wisconsin, Madison, USA 116pp. Remington, T. E., and C. E. Braun. 1985. Sage Grouse food selection in winter, North Park, Colorado. Journal of Wildlife Management 49:1055-1061. Remington, T. E., and C. E. Braun. 1988. Carcass composition and energy reserves of Sage Grouse during winter. Condor 90:15-19. �Robbins, C. T. 1981. Estimation of the relative protein cost of reproduction in birds. Condor 83:177-179. SAS Institute, Inc. 1988. SASISTAT'" user's guide, release 6.03 edition. SAS Institute, Cary, North Carolina, USA. 1028pp. Sibbald, I. R. 1976. A bioassay for true metabolizble energy in feeding stuffs. Poultry Science 55:303-308. _. 1979. Metabolizable energy evaluation of poultry diets. Recent Advances in Animal Nutrition 13:35-49. Sokal, R. R., and F. J. Rohlf. 1981. Biometry. 2nd ed. W. H. Freeman and Co., San Francisco, California, USA. 859pp. Welch, B. L., J. C. Pederson, and R. L. Rodriguez. 1988. Selection of big sagebrush by Sage Grouse. Great Basin Naturalist 48:274-279. Welch, B. L., F. J. Wagstaff, and J. A. Roberson. 1991. Preference of wintering Sage Grouse for big sagebrush. Journal of Range Management 44:462-465. Prepared by ~r----. Orrin B. M ers Graduate Research Assistant Approved by t1~2. ~ Clait E. Braun Wildlife Research Leader ��JOB PROGRESS REPORT State of: Colorado Project: Y-167-R York Plan: Job Title: 13 Upland Bird Research Job: 10 Movements. Reproductive Success. and Habitat Use by Introduced Plains Sharp-tailed Grouse Period Covered: 01 July through 31 December 1991 Author: Personnel: Yildlife Kenneth M. Giesen Clait E. Braun and Kenneth M. Giesen, Colorado Division of ABSTRACT A study plan for evaluating success of transplants of plains sharp-tailed grouse (Tympanuchus phasianellus jamesi) into historic range along the Front Range of Colorado was completed. A trip to sharp-tailed grouse range in southeastern Yyoming was completed in October to evaluate potential trapping sites and coordinate transplant activities with Yyoming Game and Fish personnel and local landowners. ��MOVEMENTS, REPRODUCTIVE SUCCESS, AND HABITAT USE BY INTRODUCED PLAINS SHARP-TAILED GROUSE Kenneth M. Giesen INTRODUCTION Plains sharp-tailed grouse (Tympanuchus phasianellus jamesi) historically occurred along the Front Range of Colorado. Sharp-tailed grouse populations declined with human settlement and were extirpated from most of their range in eastern Colorado by the late 1800's. In recent years breeding populations were documented only in Douglas County, although winter migrants or transients have been reported from Yuma, Logan, and Weld counties (Hoag and Braun 1990). Plans to increase distribution and populations of plains sharp-tailed grouse in Colorado will rely primarily on transplants (Braun et al. 1992). While numerous transplants of prairie grouse have occurred, few have been successful (Toepfer et al. 1990, Rogers 1992, Hoffman et al. unpubl. ms.). Thus, it is desirable to document responses of sharp-tailed grouse to experimental transplants and evaluate parameters potentially affecting success including movements, habitat use, mortality, and reproduction. P. N. OBJECTIVES The objectives of this project are to assist with trapping and transplanting plains sharp-tailed grouse into selected sites along the Front Range of Colorado and evaluate transplant success. Population characteristics of the transplanted population including movements and home range size, mortality, and production will be compared to a naturally pioneering sharp-tailed grouse population in Logan County near the Tamarack State Wildlife Area. SEGMENT OBJECTIVES 1. Review literature on prairie grouse introductions, movements, and habitat use. 2. Coordinate efforts with Wyoming Game and Fish personnel and affected landowners in southeastern Wyoming to locate potential trapping sites for plains sharp-tailed grouse. 3. Prepare annual progress report. RESULTS AND DISCUSSION After review of the draft recovery plan for plains sharp-tailed grouse in Colorado (Braun et al. 1992) and appropriate literature, a study plan was prepared to evaluate transplants of plains sharp-tailed grouse into the Front Range of Colorado. A work trip was taken to southeastern Wyoming in October to meet with Wyoming Fish and Game personnel and explore habitats occupied by sharp-tailed grouse in Laramie and Goshen counties. Wyoming personnel had little information on sharp-tailed grouse populations (lek surveys, hunter harvest) in these areas, but observations indicated adequate populations existed for trapping and transplanting. �I ]1.+ LITERATURE CITED Braun, C. E., R. B. Davies, J. R. Dennis, K. A. Green, and J. L. Sheppard. 1992. Plains sharp-tailed grouse recovery plan. Colorado Div. Wi1d1., Denver. 33 pp. Hoag, A. W., and C. E. Braun. 1990. Status and distribution of plains sharptailed grouse in Colorado. Prairie Nat. 22:97-102. Hoffman, R. W., W. D. Snyder, G. C. Miller, and C. E. Braun. (in prep.). Reintroduction of greater prairie-chickens in northeastern Colorado. Rogers, R. D. 1992. A technique for establishing sharp-tailed grouse in unoccupied range. Wi1d1. Soc. Bull. 20:101-106. Toepfer, J. E., R. L. Eng, and R. K. Anderson. 1990. Transplanting prairie grouse: what have we learned? Trans. North Am. Wi1d1. and Nat. Resour. Conf. 55:569-579. Prepared by _ .• ~~....;.....;._;..:...:.'#I._..:;.L~~·....;.... __ Kenneth M. Giesen Wildlife Researcher C �JOB PROGRESS REPORT < <. State of: Project: ~C~o~l~o~r~a~d~o ~W_-~1~67~-~R~ 14 Work Plan: Job Title: _ Job Upland Bird Research 4 Movements. Reproductive Success. and Habitat Use by Introduced Greater Prairie-chickens Period Covered: Author: _ 01 January through 31 December 1991 Grant M. Beauprez Personnel: Clait E. Braun, Shane Briggs, Larry Rogstad, Mike Schroeder, Colorado Division of Wildlife; Grant M. Beauprez, Jennifer Clarke, University of Northern Colorado ABSTRACT Greater prairie-chickens (Tympanuchus cupido pinnatys) were captured on leks in Colorado and Kansas with walk-in traps during March-April 1991. The birds were released between 2 and 9 April at Pinneo and Yells Ranch, Colorado. Forty-three birds (23 hens, 20 males) were released at Pinneo, while 50 (23 hens, 27 males) were released at Yells Ranch. Twenty-four birds (6 hens and 6 males at each site) were equipped with battery-powered, necklace-attached radio transmitters, and were periodically relocated to obtain data on survival, movements, lek establishment, and nesting. Birds were tracked from 2 April through 31 December. Eight birds were depredated (3 males at Pinneo; 2 males, 3 females at Wells Ranch), 7 birds lost their radio transmitters (3 males, 1 female at Pinneo; 2 males, 1 female at Wells Ranch), and radio contact was lost with 7 birds (4 females at Pinneo; 2 males, 1 female at Wells Ranch). Eight leks were formed (5 at Pinneo; 3 at Yells Ranch). The maximum number of males on any lek was. 7 at Pinneo. Seven hens were known to have nested (5 at Pinneo, 2 at Yells Ranch), and 6 were successful (4 at Pinneo, 2 at Wells Ranch). Mean distance of nests from the nearest lek was 2.9 km. Average clutch size was 11.8 eggs (range 10-16). The maximum documented dispersal distance was 79 km by a hen released at Yells Ranch and found at the Pinneo study area. Birds from Yells Ranch had a mean dispersal distance of 20.1 km compared to 9.0 km for Pinneo birds. ��111 MOVEMENTS, REPRODUCTIVE SUCCESS, AND HABITAT USE BY INTRODUCED GREATER PRAIRIE-CHICKENS Grant M. Beauprez The greater prairie-chicken originally ranged over much of the central and eastern Great Plains of North America (Aldrich 1963); it's distribution has been greatly reduced due to destruction of native grassland habitats (Aldrich 1963, Jones 1963, Christisen 1969, Johnsgard 1983). The first record of greater prairie-chickens in Colorado occurred in 1897 in the extreme northeast part of the state (Cooke 1898). Evidence suggests that greater prairie-chickens markedly expanded their range west and north with human settlements and advent of grain farming during the late 1800's and early 1900's (Sclater 1912, Schorger 1944, Beck 1957, Stempel and Rodgers 1961, Christisen 1969, Horak 1985). However, with intensified farming, overgrazing, and a series of drought years in the 1930's, their distribution and numbers in Colorado markedly decreased (Evans and Gilbert 1963). By 1963, the reported number of greater prairie-chickens in Colorado had dropped to 700-800 (Evans 1964). In 1973, population estimates were as low as 600 birds (Graul 1975) and the greater prairie-chicken was declared endangered under Colorado's Nongame, Endangered, or Threatened Species Conservation Act (Title 33, Article 8, Colorado Revised Statutes) (Pusateri 1990). The most current population estimates (1981-83) indicate that at least 3000 and possibly 6000 birds were present in Yuma, Washington, and Phillips counties (VanSant and Braun 1990). In 1990, the Colorado Division of Wildlife prepared a greater prairie-chicken recovery plan (Pusateri 1990). The main objective of this plan is to remove the greater prairie-chicken from the state's endangered and threatened list by 1995. An eventual goal is to classify the greater prairie-chicken as a game species. Attainment of these goals involves increasing -the greater pra1r1echicken's distribution in the state by means of transplanting birds into previously occupied and unoccupied range. P. N. OBJECTIVES The objectives of this study are to successfully transplant greater pra1r1echickens to two sites in northeastern Colorado, evaluate the success or failure of greater prairie-chickens to establish breeding populations at the two sites and in surrounding areas, and define guidelines for introduction of greater prairie-chickens into new or previously occupied habitats. < < �118 SEGMENT OBJECTIVES 1. Review literature on prairie grouse introductions, movements, reproduction, and habitat use. 2. Periodically relocate all radio-marked greater prairie-chickens at the Pinneo and Wells Ranch release sites until the radios fail or are lost. 3. Ascertain seasonal movements of all radio-marked greater prairiechickens. 4. Document establishment and attendance at leks. 5. Determine nest establishment and nest success of radio-marked greater prairie-chickens. 6. Document juvenile recruitment. 7. Identify habitats used by radio-marked greater prairie-chickens. 8. Compile data, analyze results, and prepare reports/thesis and publish findings in appropriate technical journals. STUDY AREA Greater prairie-chickens were studied at two separate areas. One area (Wells Ranch) was 26 km east of Greeley, in Weld County, and the other area (Pinneo) was19 km southeast of Brush, in Washington County. Transplant stock for the Wells Ranch was obtained from southcentral Kansas near Winfield, and stock for Pinneo was obtained in Yuma County, Colorado near Wray. The Yuma County area is characterized by rolling sandhills with a mix of sand sagebrush, grasses, and nearby agricultural fields. The Kansas site was more mesic with tall grass pra1r1e in a landscape of rolling hills with exposed rock on side hills and wooded draws or agricultural fields at lowest elevations. METHODS Greater prairie-chickens were captured on leks with walk-in traps (Schroeder and Braun 1991). Captured birds were weighed, classified to age and sex, .and marked with a serially-numbered aluminum band on the right leg and colored plastic bandettes on both legs (red at Pinneo, green at Wells Ranch). The two releases were completed between 2 and 9 April 1991. Forty-three birds (23 hens, 20 males) were released at Pinneo, while 50 (23 hens, 27 males) were released at Wells Ranch. Twenty-four birds (6 hens and 6 males at each site) were equipped with battery-powered, necklace-attached radio transmitters (Holohil Inc., Woodlawn, Ont.). Radio-marked prairie-chickens were relocated using a Telonics TR-2 portable receiver and a hand-held, 3-element yagi antenna. Each bird was visually observed once every 7-14 days. Additional observations (at least 2 every 7 days) were obtained by triangulation. Three �119 or more azimuths were obtained <1.5 km of target transmitters and at anglesof-incidence >35 degrees and <145 degrees (Schroeder 1991). Locations of radio-marked birds, leks, and nests were recorded to.the nearest 20 m as Universal Transverse Mercator (UTM) grid coordinates (Grubb and Eakle 1988), and plotted on U.S. Geological Survey 7.5-minute topographic maps. Leks were located by systematically searching suitable habitats using a spotting scope and a parabolic microphone listening device during morning display periods. Counts of male and female greater prairie-chickens on all known leks were made 1-2 times weekly during the morning display period. Greater prairie-chicken nests were located by tracking radio-marked hens. Clutch size, incubation period, number of eggs hatched, nest fate, distance from release site, and distance from nearest lek were recorded. Three flights using a Cessna 185 with strut-mounted antennae and a Telonics receiver/scanner were made (23 Apr, 29 May, 14 Nov)· to locate missing radio-marked birds. Habitat types used and selected by radio-marked greater prairie-chickens will be described in detail during the 1992 field season. RESULTS AND DISCUSSION Lek Surveys Eight leks were located (Figs. 1 and 2) and surveyed (Tables 1 and 2). The mean distance of leks from release sites was 7.0 km for Pinneo and 10.9 km for Wells Ranch. The maximum number of males on any lek was 7 on lek #4 at Pinneo. No females were ever observed on a lek, however, 0906 was near lek #1 at Pinneo on several occasions during the morning display period. Also, female 0369 was 2.8 km west of lek #1 at Wells Ranch with a non-radio-marked male on one occasion. Lek #3 at Pinneo was discovered on 14 May in an alfalfa field, 1.7 km southwest of the release site with 4 displaying males in attendance. However, subsequent visits to this site showed no males in attendance. Nesting Seven radio-marked hens definitely nested (5 at Pinneo, 2 at Wells Ranch) (Figs. 1 and 2, Table 3). At Pinneo, 4 hens successfully nested and a fifth hen was on a clutch of ~l eggs until 21 May. She was no longer on the nest after this date, but was still in the area until the end of October. It is unknown if she was successful as her nest was not relocated after she left it. The 2 hens that nested at Wells Ranch were both successful. Average clutch size for 5 nests was 11.8 eggs (range 10-16). It is unknown how many eggs were in the clutches of two of the hens as no opportunity to count their eggs occurred because they were not located away from their nests. Three eggs failed to hatch (10 of 11 from 0896 and 9 of 11 from 0378). The mean distance of nests from leks was 2.9 km suggesting that hens were attracted to the leks. Five of seven nests were in areas with heavy sand sagebrush (ArCemisia filifolia), and were well hidden within the vegetation. Another nest was in dense, tall grass while the final nest was in a wheat field. Brood counts conducted on 21-22 July revealed that 3 hens at Pinneo (0906, 0896, 0554) had broods consisting of at least 10, 3, and 1 chicks respectively. Females 1096, ~ « �120 PINNEO STUDY AREA ;R56~ T6 N I : ---If---I-R1r~-~---l---- N 'T" -Rl4\J--- ---- ________8>.3~/ ;-_ I I i1 ii- / • BRUSH ~ /' V / COLORADO I I I I iI , I I I I I I I 1 ° /' , ./ V V • i:J !--- LEKS ° NESTS ° fa .--V 1- • , ,, ,, ,, ,, ,,, ,, T 4N ,, ,, , ,, ,, ,, , X RELEASE SITE L. .O_C iBH US ~---~ :, I ./ I J '/ V I I V [L -~ ,/ I r-.. I I I I !'- r-. ~ ,, ,, I. ·,1' I I I T3 N , ,, , ,T ,,, 5N , ,, ../ I I I I T4 N : T6 N ,,, , ,,, /' I T5 N --- -R52Y{, <, I I I <, r-......... I ~ = "" I I I \. ';!I I 1 , 3. ' \ ~' ,. .. I I I I I I T2 N i I I I I I I ! , ,, ,, ,, , I I I I ! T1 N ,, , I I ,---- ---- .•-_ •. R56W I •.. :" ,, , ,T ,, 3N ,, , ,, ,, ,, ••••• ,,, ,, ,, : :T , 2N ,, , ,, --- •.•..._ --- R55W --- --- --- --- --- :T1 N __ 1- R54W --- _- ---- _ •.•. -.. --- .__ . •.-•.•. _.- •._-- R53W , ---..,~ R52W Fig. 1. Pinneo study area, Five leks and nests of five radio-marked hens were located. �WELLS R65W •••~ ••• r'" II •• ••••••• );tQh<'ii. ••••••• ... ... Elfi .~ ... .... ..8QQ : ~ I r-'B ~Rt ES JIL I E H vy- 26 - l- __.fI"!_ I ,...... """'" . 2. ~ Wy -3 l~ <, III... ~ i. ~. ••••• "\.... ~ I L~ TE GREELEY , ! 1\ ~RI VEf S I [ E ~ RE' ERYOI 'l1li C '-., r---.."'0111~ 0 I'--. ~ ~V ~ -L ~ r- ]_ COLORADO M I I I I I • I I I I I I I • LEKS 0 NESTS X .. • ,..,. :..... I R65W ---- ---~------- Fig. 2. Wells ........ - I RELEASE I I Ranch study area. Three R62W leks and nests I I SITE .... R63W I I R ,~ I ~ ~ -, :T 4N I I J '\ I ~ : '-,1,: : 't : --- ....t... Jl.,.J,."l, ..Jl.,. --- --- -_ ~------- -- R64W ,--~ ~ C:_T il:'Dci I I I I I : I ,......_ I ! : : T 5N ~ ~ r-, ~I I I T3 N ! I ~ r- I I I R. I I I T4 N ~ I I - "•..•.... -.__ •.......•••.. • l---- I T 6N i I I I I I I ! 3. " I I I I 0 I ~ 'f" I «:~ V If I I I : (RE EL ""y ., AREA / I I I I I I I T5 N: STUDY R91W." ... ." "" ~9 .W ••"." " I I I T6 N RANCH .•.. of two radio-marked 'T : 3N : ".1..,. ... ...J.... ... R61W I I : ... _I .• , 1 1: •••.••.••.•• R60W hens were located. I-' N I-' ~~ �122 Table 1. Location of and attendance at greater prairie-chicken leks formed by birds released at Pinneo, < < Colorado, 1991. VTM's Lek Legal location Range (West) Section Observation date .ti males NW 17 Apr 19 Apr 21 Apr 23 Apr 24 Apr 28 Apr 04 May 10 May 01 Jun 3 2 3 2 4 0 1 1 0 1 NE 24 Apr 26 Apr 28 Apr 04 May 10 May 11 Jun 4 4 2 0 0 2 54 5 SE 14 May 21 May 4 0 4 54 19 SW 03 Jun 05 Jun 08 Jun 11 Jun 20 Jun 7 7 6 3 1 4 54 19 SW 03 Jun 05 Jun 08 Jun 3 1 0 Township (North) Meters East Meters North 1 633700 4447300 2 54 4 2 629540 4447880 2 55 3 632960 4446800 2 4 630120 4461200 5 630680 4461280 Quarter observed �l.L') Table 2. Location of and attendance at greater prairie-chickens leks formed by birds released at Wells Ranch, '.'. Colorado, 1991. UTM's Lek Township (North) Legal Location Range (West) Section Observation Date N males Meters East Meters North 1 551721 4471620 5 63 13 SW 01 03 05 09 12 17 23 24 30 07 May May May May May May May May May Jun 6 5 5 4 4 3 3 0 3 0 2 565260 4476940 6 61 32 SE 04 Jun 06 Jun 07 Jun 10 Jun 12 Jun 19 Jun 4 1 1 6 5 0 3 568260 4477200 6 61 34 SE 04 06 10 12 19 4 3 3 1 0 Quarter Jun Jun Jun Jun Jun observed �Table 3. Nesting activity of greater prairie-chickens released at Pinneo and Wells Ranch, Colorado, 1991. I-' N Freq. Age Date of Date of nesting8 hatch Distance from Nearest lek{km) Clutch release area{km) size ~ !! eggs hatched Fate of nest pinneo 0976 y 31May 0906 A 0896 Unknownb 11 Jun #5 (5.5) 17.1 All Lost contact with hen after 11 Jun. 10 May 8 Jun #1 (0.6) 1.4 16 16 Flushed with 10 chicks on 21 Jul. y 31 May 27 Jun #4 (1.0) 14.8 11 10 Flushed with 3 chicks on 21 Jul. 0554 A 31 May 27 Jun #5 (0.7) 14.0 All Observed with 1 chick on 21 Jul. 1096 y 13 May Unknown #5 (1.2) 12.8 11 Unknownb Unknown? Was no longer on nest after 31 May. Not flushed with any chicks. Wells Ranch 0.~40 y 17 May 19 Jun #1 (9.8) 11.7 10 10 Not flushed with any chicks. 0378 A 04 Jun 6 Jul #2 (1.2) 14.6 11 9 Not flushed with any chicks. aDate when first observed on a nest. bClutch size was unknown because hen was not observed away from nest. cFailed to relocate nest after hen left. �125 0440, and 0378 were not flushed with a brood. However, this may not have been a true indicator of their brood status. It is possible that not all broods flushed when approached, that broods were separated from hens when the hens flushed or there may have been significant mortality among broods. Brood hens stayed in areas with good sand sagebrush and grass cover, and high concentrations of insects (grasshoppers). Telemetry Investigations Two hundred and fifty-five radio locations were obtained from April through December. Twelve birds (6 males, 6 females) accounted for 90% of the radio locations (Tables 4 and 5). At Pinneo, radio contact was lost with 7 birds (5 females, 2 males) within 5 days post-release while at Wells Ranch contact was lost with 8 birds (5 females, 3 males) within 7 days post-release. A 3-hour aerial search on 23 April was successful in locating 5 birds (3 females, 2 males) from Pinneo and 7 birds (4 females, 3 males) from Wells Ranch. However, ground contact was not made with 2 females from Pinneo nor with 3 females and 3 males from Wells Ranch. A second aerial search on 29 May was successful in locating 2 femaies from Pinneo and 2 males and 3 females from Wells Ranch. Radio contact was confirmed from the ground for all of these birds. Eight mortalities were documented; 3 males from Pinneo and 2 males and 3 females from Wells Ranch. Five mortalities were caused by mammalian predators and two by raptors. One female from Wells Ranch was shot on 27 November southwest of Riverside Reservoir on the Eagle's Nest Ranch. Radio transmitters were lost from 7 birds (3 males, 1 female at Pinneo; 2 males, 1 female at Wells Ranch). No evidence of predation could be found for any of these birds. As of 31 December, locations of 2 birds were known (one female at each site) and location/fate of 7 birds were unknown (Tables 4 and 5). The maximum distance any bird was located from the release site was 79 km. This bird was an adult female (0288) released at the Wells Ranch. She was located by aerial search on 29 May in the same area as several birds from Pinneo between Interstate 76 and Highway 34. She was found dead on 20 June. It is unknown if she was nesting. The mean dispersal distance for all birds at both sites was 14.5 km (Tables 4 and 5). Birds from Wells Ranch had a mean dispersal distance of 20.1 km compared to 9.0 km for Pinneo birds. This may indicate the Pinneo site has more suitable habitat within a smaller range than the area around Wells Ranch. Future habitat analysis will test this hypothesis. Females at both sites (Wells Ranch-27.0 km; Pinneo-12.l km) dispersed farther than males (Wells Ranch-13.1 km; Pinneo-3.8 km). This may indicate that females range farther when searching for suitable nesting habitat. Dispersal from the release site at Pinneo was oriented west and northnorthwest (Fig. 1). Four hens (1096, 0976, 0896, 0554) moved approximately 14 km north-northwest to an area between Highway 34 and Interstate 76. Two males (0079, 0018) localized approximately 5 km west of the release site where they were observed displaying on lek #2. One female (0906) localized within 1.5 km of the release site while the final hen (0968) was not located by aerial or ground search after the release. One male (0301) localized within 1 km of the < < �126 Table 4. Movements of greater prairie-chickens released at Pinneo, Colorado, 1991. N radio Freq. Sex locations Distance from release site where bird localized (km) Fate 0976 Y F 3 0968 A F 0 0906 A F 16 1.5 0896 y F 14 14.8 Nested successfully. Found transmitter on 31 Aug. 0554 A F 21 14.0 Nested successfully. Lost contact after 20 Sep. 1096 y F 20 13.2 Nest success unknown. Still alive on 31 Dec. 0301 y M 12 2.1 0280 A M 1 Found dead on 6 Apr. 0109 y M 3 Observed displaying on lek #1 in association with 0301 on 17 Apr. Found dead on 28 Apr. 0079 A M 20 0048 A M 4 0018 y M 21 17.0 Nested successfully. Lost contact after 11 Jun. Not located after release. 4.7 Nested successfully. Lost contact after 20 Sep. Observed displaying on lek #1. Found transmitter on 10 Jul. Observed displaying on lek #2 in association with 0018. Found transmitter on 27 Aug. Found transmitter on 23 Apr. 4.7 Observed displaying on lek #2 in association with 0079. Found dead on 20 Sep. <"' �127 Table 5. Movements of greater prairie-chickens released at Wells Ranch, Colorado, 1991. !! radio Freq. Sex locations Distance from release site where bird localized (km) Fate 0449 Y F 0 0440 y F 17 11.7 Nested successfully. Was shot on 27 Nov. 0378 A F 27 14.6 Nested successfully. 31 Dec. 0369 A F 4 2.8 0310 y F 2 0288 A F 5 78.9 Found dead on 20 Jun 79.1 km from release site. 0419 y M 14 16.4 Observed displaying on lek #3 in association with 0349 and 0339. Found transmitter on 13 Jul. 0410 y M 3 3.8 0349 A M 24 16.2 Observed displaying on lek #3 in association with 0339 and 0419. Found dead on 25 Oct 0339 y M 23 16.1 Observed displaying on lek #2 on 4 Jun. Observed displaying on lek #3 on 6 Jun in association with 0349 and 0419. Lost contact after 3 Oct. 0319 A M 0 Located by aerial search on 23 Apr. Lost contact after 23 Apr. 0089 A M 1 Found dead on 18 Apr. Not located after release. Still alive on Lost contact after 29 May. Found transmitter on 21 Nov. Found dead on 18 Apr. Found transmitter on 25 Apr. �128 release site and was observed displaying on lek #1 but later moved 5 km west of the release site near 0079 and 0018. Two males (0280, 0109) were found dead within 1.5 km of the release site within 30 days post-release. The final male (0048) lost his radio 0.8 km from the release site. The radio was found on 23 April. At Wells Ranch, dispersal was oriented east, south, and southeast (Fig. 2). Four birds (3 males, 1 female) localized 16 km east of the release site in an agricultural area of wheat and summer fallow. All 3 males were observed displaying on leks. Bird 0089, an adult male, was found dead on 18 April, 3.7 km west of the release site. On 25 April, the radio collar of 0410, a yearling male, was found 3.8 km west of the release site. Bird 0319, an adult male, was located east of the National Hog Farm Complex by aerial search on 23 April, however, ground contact was not made with this bird. The second aerial search on 29 May also failed to locate this bird. Bird 0449, a yearling female, was not located after release by air or ground search. Bird 0310, a yearling female, was found dead on 18 April, 1 km west of the release site. Bird 0369, an adult female, was located by aerial search on 23 April, 26 km east of the release site. On 30 April, this same bird was located 0.7 km south of the release site. Contact'was lost with this bird after 3 May. Her radio transmitter was found on 21 November approximately 7 km southeast of the release site on the National Hog Farm property. Bird 0440, a yearling female, localized 11.7 km southeast of the release site. A snowstorm in late October induced some migratory movements by the remaining radio-marked birds. One female (0378) from Wells Ranch was found approximately one mile south of Jackson Reservoir in a corn stubble field. One female (1096) from Pinneo wintered along the South Platte River in the corn stubble fields approximately 2-3 miles southwest of Prewitt Reservoir. Both of these birds were still in these areas as of 31 December. I also flushed one flock of 8 birds near the release site at Pinneo following the snowstorm in October. There were several other reports of flocks of prairiechickens being seen along the South Platte River between Hillrose and Prewitt Reservoir from October through December. LITERATURE CITED Aldrich, J.W. 1963. Geographic orientation of North American Tetraonidae. J. Wildl. Manage. 27:529-545. Beck, J.V. 1957. 25:8-12. The greater prairie chicken in history. Nebraska Bird Rev. Christisen, D.M. 1969. National status and management of the greater prairie chicken. Trans. North Am. Wildl. and Nat. Resour. Conf. 34:207-217. Cooke, W.W. 1898. Bulletin 37. Further notes on the birds of Colorado. An appendix to Colorado Agric. ColI. Bull. 44. Tech. Ser. 4:147-176. Evans, K.E. 1964. Inventory of greater prairie chickens. Colorado Dep. Game and Fish, Fed. Aid Rep. W-37-R-17. April; pp. 343-367. « �, and D.L. Gilbert. 1963. Grouse of the grasslands: the greater prairie chicken in Colorado. Colorado Outdoors. 12(6):15-18. Graul, W. 1975. Grassland boomers. Colorado Outdoors. 24(6):24-28. Grubb, T.G., and W.L. Eakle. 1988. Recording wildlife locations with the universal transverse mercator (UTM) grid system. U.S. Dep. Agric., For. Serv., Res. Note RM-483. 3 pp. Horak, G.J. 1985. Kansas prairie chickens. Wildl. Bull. 3. 65 pp. Kansas Fish and Game Comm. Johnsgard, P.A. 1983. The grouse of the world. Lincoln. 413 pp. Univ. Nebraska Press. Jones, R.E. 1963. Identification and analysis of lesser and greater prairie chicken habitat. J. Wildl. Manage. 27:757-758. Pusateri, F.M. 1990. Greater prairie-chicken recovery plan. Wildl. Fort Collins. 25 pp. Colorado Div. Schorger, A.W. 1944. The prairie chicken and sharp-tailed grouse in early Wisconsin. Trans. Wisconsin Acad. Sci., Arts, and Letters. 35:1-59. Schroeder, M.A. 1991. Movement and lek visitation by female greater prairiechickens in relation to predictions of Bradbury's female preference hypothesis of 1ek evolution. Auk. 108:896-903. _____ , and C.E. Braun. 1991. Walk-in traps for capturing greater prairiechickens on leks. J. Field Ornitho1. 62:378-385. Sc1ater, W.L. 1912. A history of the birds of Colorado. London, U.K. 576 pp. Stempel, M.E., and S. Rodgers, Jr. Iowa. Proc. Iowa Acad. Sci. Witherby and Co., 1961. History of prairie chickens in 68:314-322. Van Sant, B.F., and C.E. Braun. 1990. Distribution and status of greater prairie-chickens in Colorado. Prairie Nat. 22:225-230. Prepared by: « ��131 JOB PROGRESS REPORT State of: Colorado Project: W-167-R Upland Bird Research 17 Job Title: Population Dynamics of White-tailed Ptarmigan Period Covered: Author: Job __z__ Work Plan: 01 January through 31 December 1991 Clait E Braun and Kenneth M. Giesen Personnel: Kathy Martin, University of Toronto; Clait E. Braun and Kenneth M. Giesen, Colorado Division of Wildlife ABSTRACT Long-term studies of populations of white-tailed ptarmigan (Lagopus leucurus) were continued at hunted (Mt. Evans) and unhunted (Rocky Mountain National Park) areas in Colorado through 1991. Densities of breeding ptarmigan at Rocky Mountain National Park decreased while those at Mt. Evans were essentially stable. Nest success at Mt. Evans was poor in 1991 while that in Rocky Mountain National Park increased over that recorded in 1990. At least 10% of the banded birds alive at Mt. Evans were reported shot in 1991. Nine of the 10 banded birds reported harvested were banded in 1989 and 1990. Nonreporting of bands may be an important problem. ��lJJ POPULATION DYNAMICS OF WHITE-TAILED PTARMIGAN Clait E. Braun and Kenneth M. Giesen Long-term studies of trends in population size and investigation of reasons for fluctuations in size of tetraonid populations are lacking. Studies on the population dynamics of unhunted and hunted populations of white-tailed ptarmigan were initiated in Colorado in 1966 and have continued essentially uninterrupted at 2 sites. Studies of the unhunted population (Rocky Mountain National Park) identified possible short-term cycles of 7-8 years with an amplitude of 25-30% between high and low breeding densities. Conversely, studies of the manipulated population (hunted) at Mt. Evans have not indicated any cyclic pattern and it would appear that controlled hunting may mask any long-term trend that may occur. This study is designed to examine the question whether white-tailed ptarmigan are truly cyclic and whether hunting affects the apparent oscillations. P. N. OBJECTIVES The goals of this investigation are to be able to predict the length and amplitude of cycles in white-tailed ptarmigan in Colorado, to examine the impact of hunting on cycles, and to clarify underlying causes of the apparent cycles. SEGMENT OBJECTIVES 1. Conduct breeding (May-Jun) and brood (Aug-Sep) censuses ptarmigan using tape-recorded calls of males (breeding) (broods). 2. Censuses will be conducted on previously established, defined study areas at Mt. Evans (hunted) and at Rocky Mountain National Park (unhunted). 3. Capture (noose poles) and band (aluminum and plastic color-coded bands) all unmarked white-tailed ptarmigan encountered on study areas at Mt. Evans and at Rocky Mountain National Park. 4. Individually identify all ptarmigan observed on study areas at Mt. Evans and Rocky Mountain National Park through use of binoculars. 5. Make hunting season and bag limit recommendations for Mt. Evans and collect hunting data through use of volunteer wing barrels and hunter field checks. 6. Compile data, analyze results, and prepare progress of white-tailed and chicks reports. �134 STUDY AREA AND METHODS Areas investigated were Mt. Goliath-Mt. Evans in Clear Creek County and at Tombstone Ridge-Sundance Mountain to Fall River Pass in Rocky Mountain National Park in Larimer County. The physiography, geology, location, and vegetation of these study areas have been previously described (Braun 1969, 1971; Braun and Rogers 1971; Giesen 1977). Ptarmigan were located through use of tape-recorded calls (Braun et al. 1973), captured through use of telescoping noose poles (Zwickel and Bendell 1967) as described by Braun and Rogers (1971), and classified to age and sex and banded following Braun and Rogers (1971). Age of chicks was estimated following Giesen and Braun (1979). Numbered plastic bandettes were not used as in earlier years (Braun and Rogers 1971) as a color-code system using up to 4 different colored plastic bandettes was instituted in 1977-78. A check station was operated on the Mt. Evans highway during the opening weekend of the ptarmigan season in that area. A volunteer wing collection station was available to hunters in the area when the check station was not in operation until the season closed. RESULTS AND DISCUSSION Breeding Densities Mt. Evans.--Timing of breeding events in the Mt. Evans area was about the same in 1991 as in 1990. During the May-early June interval, 13 pairs were identified, 3 less than in 1990. Only 5 of 13 males identified were yearlings while 8 of 20 hens were yearlings. Thus, recruitment of yearlings was higher than in 1990. Despite fewer males in 1991, the breeding density increased slightly (Table 1). Rocky Mountain National Park.--Timing of breeding events on the Trail Ridge study area was similar to the long term average and about 1 week later than in 1990. Surveys of ptarmigan on breeding territories along Trail Ridge Road in May and June indicated a minimum population of 61 birds and included 26 pairs and 9 unpaired males. This represents a 19% decline over 1990 and is less than 50% of the breeding densities recorded during peak years in 1969 and 1976. The decreased breeding density reflected low survival of banded adult males (34 of 57, 59.6%) and females (17 of 38, 44.7%) from 1990. There was no recruitment of chicks banded in 1990, although yearlings comprised 42% of all adult ptarmigan identified in 1991. Nesting Success and Brood Size Mt. Evans.--Twenty hens were located during August-early September 1991 on or immediately adjacent to the study area. Sixteen (80%) were without broods while only 4 had broods. Average brood size to 1 September was poor (2.7 chicks/hen). Hatch dates for 13 chicks varied from 13 July to 3 August. Rocky Mountain National of hens with broods and 16 hens observed during success rate of 50%, an Park.--Nest success was estimated from the proportion without broods observed in July and August. Eight of summer surveys were with broods for an estimated nest 85% increase from 1990. The median hatch date �1,)::> calculated from wing molt of 28 juveniles was 12 July (range 4-24 July) and was similar to the 1966-90 average. Brood size in August averaged 3.4 chicksjhen (range 2-6). Table 1. White-tailed ptarmigan breeding densities (birdsjkm2), Colorado 1966-91. Study area Year 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 Rocky Mountain National Park (5.5 km2) 11.3 9.8 11.5 12.0 9.6 9.1 8.7 7.8 8.0 11.1 13.5 12.9 10.7 8.7 8.4 8.2 7.8 6.7 5.8 6.0 4.5 6.0 5.4 6.2 7.6 6.7 Mt. Evans (4.0 km2) 3.0 2.7 2.7 2.2 2.0 4.2 7.5 6.2 6.2 6.2 6.7 > 6.0 7.5 10.3 9.5 9.0 6.5 6.5 8.0 8.0 6.5 5.0 7.5 8.0 8.0 8.2 Harvest Mt. Evans.--The hunting season at Mt. Evans in 1991 opened on 14 September and closed on 6 October (23 days) with a bag and possession limit of 3 and 6. Thus, the season was delayed 1 week from the statewide opening as it was in 1981 and 1986-90. The season opening was delayed 2 weeks from 1978 to 1980 and 1982 to 1985. Prior to 1978, experimental seasons were in effect (19701976) or the season opened with the statewide grouse seasons (dates from 17 Aug to 14 Sep). Unlike 1987 and 1988 when the Mt. Evans road was closed due to reconstruction (Lincoln Lake area in 1987, above Ptarmigan Flats in 1988), �136 the Mt. Evans road was open to Summit Lake throughout the season. Twenty-one hunters were checked on 14-15 September. These hunters observed 50 ptarmigan and harvested 4 of which all were banded. Nine additional wings (7 on 20 Sep 1991, 2 on 29 Sep 1991) were received in the Mt. Evans wing collection barrel (but no bands) and bands from 6 birds were received through the mail. Thus, at least 10 banded birds were harvested in 1991 (4 of 13 possible from 1989, 31%; 5 of 25 possible from 1990, 20%; 1 of 53 possible from 1991, 2%). This represented at least lOX of the birds believed alive in September 1991 on the study area. However, it is possible (probable) that not all banded birds harvested were reported. LITERATURE CITED Braun, C. E. 1969. Population dynamics, habitat, and movements of whitetailed ptarmigan in Colorado. Ph.D. Thesis, Colorado State Univ., Fort Collins. l89pp. 1971. Habitat requirements of Colorado white-tailed ptarmigan. West. Assoc. State Game and Fish Comm. 51:284-292. Proc. _______ , and G. E. Rogers. 1971. The white-tailed ptarmigan in Colorado. Colorado Div. Game, Fish and Parks Tech. Publ. 27. 80pp. _______ , R. K. Schmidt, Jr., and G. E. Rogers. 1973. Census of Colorado whitetailed ptarmigan with tape recorded calls. J. Wildl. Manage. 37:90-93. Giesen, K. M. "1977. Mortality and dispersal of juvenile white-tailed ptarmigan. M.S. Thesis, Colorado State Univ., Fort Collins. 55pp. _______ , and C. E. Braun. 1979. A technique for age determination of juvenile white-tailed ptarmigan. J. Wildl. Manage. 43:508-511. Zwickel, F. C., and J. F. Bendell. J. Wildl. Manage. 31:202-204. 1967. __;;;&,--V...;;_·_.z._.--+~-==""""",,_ Prepared by _ Clait E. Braun Wildlife Research Leader Kenneth M. Giesen Wildlife Researcher C A snare for capturing blue grouse. � https://cpw.cvlcollections.org/files/original/12ebd80b9cd347febbcd8e280db11ae4.pdf 654db8da94918a4428c03d42d3ae415d PDF Text Text lJl JOB FINAL REPORT State of ~C~o~l~o~r~a~d~o~ _ Project: W-152-R(W-165-R Upland Bird Research Work Plan: -=2..=1 : Job _3_ Job Title: Sandsage-Bluestem Prairie Renovation Period Covered: 01 January 1984 through 31 December 1991 Author: Warren D. Snyder ABSTRACT Prescribed burns, tillage~herbicide and herbicide renovation, and revegetation treatments were applied to sites within the Tamarack Prairie during 1984-86 to increase the proportion of tall, warm-season grasses and height-density of standing residual, and reduce the composition of sand sagebrush (Artemisia filifolia). Evaluations through spring 1991 demonstrated that prescribed burns that coincided with emergence of warm-season grasses reduce4 heightdensity for: 1 year post treatment on all sites, several years if precipitation was below average, and increased it for one or more if precipitation was above average. Precipitation received prior to and after a fire was the primary factor influencing vegetation" response. The heightdensity value of sand sagebrush was severely impacted for several years by fire. Burns conducted in late spring more severely impacted sage, however, it was seldom killed. Composition of blue grama (Bouteloua gracilis), needleand-thread (Stipa comata), prairie sandreed (Calamovilfa longifolia), and sand dropseed (Sporobolus cIYtandrus) was not markedly altered by a single spring burn. Needle-and-thread, a cool-season species, was most severely impacted during the first growing season, but recovered with dramatic seed production during the 2nd year. Crown cover of blue grama, prairie sandreed, and sand bluestem (Andropogan hallii) increased when burned under favorable moisture conditions, whereas sand dropseed was little affected by fire. Sample sizes for perennial and annual forbs were too small to provide meaningful data and no consistent trends were evident. Western ragweed (Ambrosia psilostachya) increased after the 1985-86 burns but total forb composition was low and number of species did not change after fire. Revegetation (tillage to remove shallow-rooted species, application of atrazine herbicide, and seeding' to tall warm-season grasses) was effective in rapid co~version of rangeland to taller, more lodge-resistant cover with greater r'esLduaL height-density. Drilling tall grasses into undisturbed sod was ineffective as between-row competition severely suppressed seeded grasses where an interseeder opened furrows for planting prior to this study (1982-83). Tillage-herbicide renovation (1986) was highly effective in removing between-row competition and increasing composition and height-density of deep-rooted seeded species. Tillage and tillagefherbicide treatments effectively renovated deep-rooted, warm-season tallgrass species. Aerial application of 2,4-D herbicide to thin stands of sand sagebrush resulted in near total kill of sage and severe repression of forbs. Sand sagebrush was used extensively for nesting and loafing by prairie grouse. In spite of greater grass height-density within the ungrazed Tamarack Prairie than on adjacent grazed rangelands, the latter received more use by pra1r1e grouse. Thus, factors in addition to height-density must be considered in management for prairie grouse. However, prairie grouse use of the Tamarack Prairie increased steadily during the study~ "Management options to enhance the quality of the Tamarack Prairie are presented with direct application to other rangelan~s. .._._-_.._._- 111~11111~)II~)jil~imlli~~mii~1 ~mlli~11 BDOW026417 �138 RECOMMENDATIONS 1. Rangelands in eastern Colorado, such as the Tamarack Prairie, should be retained in a vigorous subclimax condition for prairie grouse. Fire, tillage; and partial revegetation are recommended in preference to grazing where management· can be directed toward prairie grouse. Such sites should not be left completely idle and unmanaged, nor should they receive annual grazing. 2. The Tamarack Prairie lacks a strong base of forbs, legumes, and foodproducing vegetation essential to prairie grouse and the site remains dominated by mid and shortgrass species of marginal value. Most other eastern Colorado rangelands have similar composition characteristics. Management procedures should strive to provide a mosaic of diverse habitat components, including food, that will provide year-long needs of prairie grouse in close proximity. 3. If ungrazed, sites (~ 130 ha) should be burned on a 8-10 year rotation to remove residual. More frequent burns, at 5-10 years, should be used where tall, warm-season grasses occur within revegetated or interseeded sites. At least 0.75 m of soil moisture should be available (based on soil probe samples) before burning. Burns should be timed to coincide with emergence of warm-season grasses following procedures summarized by Wright and Bailey (1980). Burns, conducted where sand sagebrush exceeds 15% crown cover, should be less frequent and relatively smali « 16 ha) because of slow sandsage recovery. 4. Aerial application of herbicides should not be used to thin sand sagebrush. Where needed, spraying with a tractor-mounted sprayer should be conducted in narrow, linear strips, 10-30 m wide, to create mosaics of openings that impact < 25% of the site. Less than 50% of the openings should be revegetated to tall, warm-season grasses « 1 ha). Other openings should be cultivated and seeded to seed-yielding annual forbs/grasses and to perennial legumes to provide green leafy vegetation. Periodic tillage should be used to renovate these sites and annual disturbance tillage may be needed on some sites. 5. Tillage destruction of shallow-rooted grasses, especially needle-andthread, and seeding of tall, warm-season mixtures into small « 1 ha) linear tracts is r~ommended in preference to int~rseeding. Su~h sites should be distributed throughout the Tamarack Prairie with a revegetation goal of 33% of the area. Where interseeded strips already exist, tillage-herbicide renovation combinations can used to release interseeded species. Seed rates should be reduced below those normally recommended in attempts to obtain moderate (as opposed to dense) stands of seeded grasses. 6. Sites dominated by indigenous pra1r1e sandreed, sand bluestem, and other deep-rooted vegetation should be renovated using a prescribed burn followed by shallow disturbance tillage to remove competing shallowrooted species such as needle-and-thread and blue grama. Direct seeding, using a range drill, into existing undisturbed range should not be used in this semiarid climate as competition from existing vegetation is too severe. �7. Application of atrazine herbicide (at low rates) (Snyder 1990~) effectively suppressed annual forbs within revegetated ~nd renovated sites (previously interseeded) and allowed switchgrass and bluestems to quickly establish. even during years when spring moisture was marginal. Other newly registered applicable herbicides may be substituted for atrazine in future plantings. 8. Two or more, 2-ha winter food plots dominated by grain sorghums are recommended on a 2 to 3-year trial basis within the Tamarack Prairie. Their use by, and retention of, prairie grouse through winter should be monitored. Patches « I ha) of alfalfa, vetches, and other legumes should be tested and monitored. Fire lines; prepared during the summer prior to burning, should be planted in fall to winter annuals such as rye, triticale, or winter wheat to provide green succulents through winter. Fire lines prepared in early spring should be planted to oatslegume (alfalfa) combinations. 9. Several large unused irrigation wells exist north of 1-76. Potentially, one of these could be changed from off-season to growing season use and water could be pumped under 1-76 to irrigate up to 65 ha within the Tamarack Prairie to raise alfalfa, corn, sorghums, etc. to benefit prairie grouse. 10. At several windmills, overflow basins, previously underlain with sheet plastic, should be tilled, seeded to legumes, and managed to retain wetmeadow vegetation. Change-of-use permits for the windmills should be obtained and drip systems (equipped with filters) should be installed to distribute water directly from the windmills. Water in eXisting stock tanks should be lowered to shallow «1 dm) depths to reduce drowning by passerines and still provide water for mourning doves, deer, and other resident wildlife. 11. Management procedures, previously described, are not compatible with intensive livestock grazing management. If grazing is used as a substitute for burning on part of the Tamarack Prairie, it should not be replicated more frequently than once ever 4 - 5 years (> 75% would remain idle each year) on sites.no larger than 40 - 50 ha using electric fences.to facilitate rotations among years .. Moderately·intense.fallwinter grazing to remove residual 'and disturb the soil while not impacting p Lant; vigor is t~e preferred procedure. 12. Vehicle noise along Interstate 76 is hypothesized as a deterrent to lek establishment closer than 1 - 1.5 km to the highway, which in turn may limit other use of the Tamarack Prairie by prairie grouse. If prairie grouse use of portions of the Tamarack Prairie proximal to 1-76 does not increase within the next 3-5 years, even with provision of food plots, new management alternatives should be considered. Among these could be exploration of exchange-af-land, or exchange-of-use for other sites away from the Interstate. For example, the narrow west 3.2 - 4.8 km (2-3 miles) of the Tamarack Prairie could be exchanged for lands south of the property that are managed by the Colorado State Land Board. Portions of rangelands north of 1-76 might also be traded while retaining hunter access rights.' Neither receives significant use by prairie grouse nor is it managed for other wildlife at the present. 13. Predator calling and trapping activities should be encouraged on and adjacent to the Tamarack Prairie to manage numbers of coyotes. �141 SANDSAGE-BLUESTEM PRAIRIE RENOVATION Warren D. Snyder INTRODUCTION Greater prairie-chickens (Typanuchus cupido) were declared endangered in 1973 under Colorado's Nongame, Endangered, or Threatened Species Conservation Act (Title 33, Article 8, Colorado Revised Statutes) (Pusateri 1990). Through the 1960's and early 1970's only a few hundred were present in Yuma County based on lek inventories. Prairie-chickens increased dramatically, and extensive range expansions occurred in the late 1970's and early 1980's, with several thousand birds present by 1982 (Van Sant and Braun 1990). These higher numbers have been sustained since. Attempts to restore the Division of Wildlife's Tamarack Prairie in eastern Logan County for greater prairie-chickens were begun in 1978. A habitat management plan, prepared by W. Busby for W. D. Graul, was submitted to R. Desilet in December 1978. Recommendations of a State Wildlife Areas Planning Committee were also submitted to R. Desilet by R. M. Hopper in October 1978. Nongame research personnel began vegetation sampling on the site, and, based on Busby's recommendation, an interseeder was acquired and native grass seeding was initiated in 1982 and 1983. Following appraisal of initial results of the interseeding effort, a consultant (L. M. Kirsch) was contracted to provide habitat renovation recommendations (L. M. Kirsch to R. M. Hopper and W. D. Graul, Sep. 1983). This study was designed to measure the impact of manipulations and to provide recommendations for future prairie restoration efforts. In 1984, the year this study was initiated, 36 prairie-chickens, trapped in Yuma County, were released on the Tamarack Prairie. Prior to the release, 1 male had been found by L. R. Crooks (District Wildlife Manager) on private rangeland during a survey of the Tamarack Prairie and adjacent lands. An additional 40 birds from Yuma County were released on the Tamarack Prairie in 1985. That spring, 5 leks (1 to 7 males/lek) were found on lands primarily south of the Tamarack Prairie. The resident population has slowly increased and expanded since then. In recent years (1989-91) a small, but expanding, population of plains sharp-tailed grouse (~ phasianellus jamesi) has become established in the area. These birds are presumed transients from Nebraska. STUDY AREA The Tamarack Prairie is the rangeland portion of the South Platte Wildlife Area (Tamarack Ranch) south of Interstate Highway 1-76 (Fig. 1). It contains approximately 1,820 ha bounded on the east by Logan County Road 93, on the west by Colorado Highway 25, and by private land and state school lands containing sandsage-bluestem prairie on the south. The elevation approximates 1,160 m progressively rising in sandy ridges and hills southeast from the South Platte River Valley. Soils are Dailey and Valent loamy sands (Amen et al. 1977). Precipitation averages approximately 40 cm (16 in.) per year. D~minant vegetation includes blue grama, needle-and-thread, sand dropseed, and prairie sandreed along with sand sagebrush. Sand b1uestem and other warmseason grasses, which are still present, were believed more prevalent prior to years of intensive grazing. �142 The Tamarack Prairie was purchased by the Colorado Department of Game and Fish (Division of Wildlife) in 1949 as part of the Tamarack Ranch, The property was primarily acquired for waterfowl hunting along the South Platte River. The rangeland portions of the Ranch continued to be grazed by cattle under lease agreements through 1977. Prior to that time it is assumed they were annually grazed by livestock following settlement of the locality. Portions of the Prairie were homesteaded and farmed, and then reverted back to rangeland. Interstate Highway 1-76 was constructed through the rangelands and completed in the late 1960's. �I T I I i I I i i i J .. l Ir III ~ Ir \ '-" --___j _ CIt N , __ •• 4 ,• ,, ,__ , 0 N -----------;~~---------N~! I I ! I I I ...I • t• , f•• Q 1&1 - ••~~ N >< E z- : ,~ ,,~ , Z 1&1 1&1 .J e o Fig. 1. Prescribed burns, renovation treatment, and revegetation treatments conducted within the Tamarack Prairie, eastern Logan County, Colorado. �144 P. N. OBJECTIVES Test renovation and revegetation techniques for increasing standing residual height-density of grasses, the proportion of tall warm-season grasses within the composition, and for reducing the quantity of sand sagebrush to <30% canopy cover in an ungrazed sandsage-bluestem prairie on the South Tamarack, South Platte Wildlife Area in northeastern Colorado. METHODS Following coordination with management personnel concerning site selection and fire management procedures, and design coordination with D. C. Bowden (statistician), two burn (treatment) sites were selected in 1984 (burns 1-84 [50 hal and 3-84 [20 hal) for evaluation (Fig. 1). The sites were mapped, gridded at 100-m intervals, and random vegetation sampling sites were positioned using a measuring wheel and compass. Approximately 5-m wide disked fire guards were placed around the burns and control areas. Burn 1 contained 9 treatment and 9 control vegetation sampling transects and burn 3 contained 4 of each. Each transect point was permanently marked using a steel post; metal pins were used to mark vegetation lines extending away from the point. In preparation for fires in 1985, 3 areas were selected, mapped, gridded at 100-m intervals, and subdivided into equal units. Random selection was used to determine burned and control portions. Due to dry conditions in spring 1985, only part of each of the 3 treatments was burned. The remainder of each was burned in spring 1986 (Fig. 1, Table 1). Each of the 3 areas contained 24 transect points (12 in each treatment and control area), or 72 transects among all areas. The 1985 burns encompassed 17 transects; 19 were contained in the 1986 burns with identical numbers in their control areas. The size and dates of burns conducted in 1984, 1985, and 1986 varied (Table 1). Management personnel tilled a fire guard around each burn, back fired along the leeward edge of the burn, and then used a progressive series of headfires. Propane torches were used in fire ignition and vehicle-mounted pumper units were used to control fires. Table 1. Characteristics of prescribed burns conducted during 1984-86, Tamarack Prairie Colorado. Phenolo~y (hei~ht cm) Stipa comata Calamovi1fa spp. ac Transects Date burned Year Site ha 1984 1 3 50.0 20.0 1985 1 2 3 17.8 26.7 14.5 124 49 44 66. 36 9 4 4 May 4 May 5 8 4 16 May 16 May 16 May 59.0 146 17 46.0 19.0 27.1 114 47 67 7 4 8 Subtotal 108.2 268 19 Subtotal 1986 1 2 3 30 Apr 23 Apr 23 Apr 15 Not emerged 50 (heading) 25 15-25 15-25 30 15 7.5-15 �14J Height-density indices (HDI) of residual vegetation within all treatments and controls were taken following Robel et al. (1970) as modifie~ by L. M. Kirsch (unpubl. rep., U. S. Fish and Wildl. Serv., Jamestown, N.D., 1977; the highest obstructed 0.5 dm was recorded using a 0.5-dm diameter square Robel pole). Sampling was conducted in March and early April subsequent to major snowfall and prior to significant green-up of vegetation. The first 4 readings (1 from each side of the Robel pole) were taken starting 5 paces to the right of the transect post, and subsequent readings were taken at 8-pace intervals in a rectangular direction around each transect within all burns and their controls. Ten stops (40 readings) were completed per transect. Sample size was reduced to 24 readings/transect in 1991. Grass-forb or sand sagebrush were recorded separately based on the primary visual obstruction when reading the Robel pole. Height-density indices of grass-forb, sandsage, and total (combined) vegetation were tested by analysis of covariance, analysis of variance, ~ tests, and regression analysis. Crown cover, species composition, and frequency of vegetation within the 1-84 and 3-84 burns were measured using metric-belt transects (Schmutz et al. 1982) during pretreatment (spring 1984) and post-treatment (mid to late summer) intervals in 1984, 1985, 1987, and 1989. A 50-m line extended from the steel post in a randomly selected direction. It was divided at 0, 12.5, 25.0, 37.5, and 50.0 intervals, and 5 7.9-m transect lines were extended 90· to the left, right, left, etc. at 5 points along the line. A 0.1-m2 frame (31.6 cm/side) was divided in half and one-half was further divided into 5 0.01-m2 segments. This frame was positioned 25 times along each 7.9-m line yielding a 2.5-m2 sample/line or 12.5 m2 /transect. Crown cover occupied by each species within each sample frame was visually estimated. Beginning in 1985, monitoring intensity was reduced by sampling alternate frames (13 instead of 25; 52%) along each 7.9-m line or 6.5 m2 /transect. Data were adjusted for analysis to directly compare with that obtained in 1984. A point-frame vegetation composition sampling procedure (Floyd and Anderson 1983) was used in mid to late summer to sample crown cover within the 1985 and 1986 burns and controls during mid to late summer from pre- through posttreatment years. A framework 0.5 x l-m in size, on telescoping legs, contained a grid of fluorescent-yellow, nylon fishing line spaced at 1 dm intervals to yield 36 sample points. A second grid was positioned 1 dm directly below the first, providing 2 pairs of cross-hairs on a vertical plane to sight past in recording vegetation. Each transect line was in a randomly selected direction, with 3 lines (7-m long) running perpendicular (left, right, left) to the main line at randomly selected points. The 36-point frame was positioned 4 times (at every other m) along each of the 3 lines yielding 144 points/line and 432 points/transect. Analysis of covariance was use in all crown cover evaluations. Within sites where prescribed burns and wildfires occurred in 1984, 1985, and 1986, individual sand sagebrush plants in clusters of 5 or 10 in random locations were marked with metal pins and monitored for survival in comparison with controls in proximal unburned locations. Precipitation gauges were placed within or near burns 1-84 and 3-84 in 1984, but could not be read immediately following each rain. Rainfall data were obtained from M. J. Gardner at the Tamarack State Wildlife Area headquarters, from H. F. Hamilton (Crook), and the U.S. Weather Service.recording station �146 (south of Sedgwick). Two automatic rain gauges that recorded each 0.025 cm (0.01 in) of rainfall were installed near burn 1-84 and east ,of burn 3-85 in spring 1985 to monitor rainfall through the growing season. Four automatic gauges were used in 1986 and subsequent years. Information was supplemented with U.S. Weather Service data during winter months as the gauges did not accurately measure snowfall. Attempts to use a soil moisture meter to determine percent moisture at 5, 15, and 30-cm depths in 1984 were discontinued because measurements were neither accurate nor meaningful. A soil probe (steel rod), approximately 1.9 m long and 1.4 cm in diameter was used to measure accumulated soil moisture starting in 1985. This device, used by agronomists for determining subsoil moisture in croplands (D. E. Smika, pers. commun.), provided reliable indices of spring subsoil moisture accumulations in the fine sands. Tests showed that when the probe was inserted by hand into the ground it consistently penetrated the moist soil, but stopped in the transition zone to dry soil. Sandy soils retain about 2.5-3.8 cm moisture/0.3 m (1 to 1.5 in./ft.) (D. E. Smika, pers. commun.). The probe was used in spring before top soils dried, hindering penetration. Leafing, budding, etc. status of plants resident on the Tamarack Prairie' was monitored at approximate 10-day intervals each spring to determine differences in plant phenology among years. Approximately 21 ha of rangeland dominated by needle-and-thread and blue grama within the northeast to middle part of the Tamarack Prairie were selected for revegetation in late winter 1985. Nineteen strips of varying length, each 26m wide, were placed perpendicular to prevailing winds. The strips were double disked with a tandem disk by management personnel after the ground thawed in late winter. Supplemental treatments included harrowing with a spike-toothed harrow and application of atrazine herbicide at 0.75 kg/ha (0.67 lb/ac); Seeding of a switchgrass-dominated tall, warm-season grass mixture followed within 1 or 2 days of herbicide application in late April 1985. Heightdensity and point-frame sampling techniques were used in subsequent evaluations. In 1986, management personnel shallow disked, applied atrazine herbicide at 0.75 kg/ha (0.67 Ib/ac), and harrowed the majority of 30 small tracts that had been interseeded to tall, warm-season grasses in 1982-83. Most contained fair to good stands which were suppressed by competition with native vegetation and annual forbs. Some, containing poor stands of grass, were reseeded. Heightdensity and metric-belt pretreatment sampling had been conducted on 1 location, so renovation treatment was applied to one-half (randomly selected) of the site. Each half contained 15 random transects (1 was subsequently lost in the treated portion), each with a single 7.9-m metric-belt line. Posttreatment evaluations of the treatment were continued. Height-density sampling of residual vegetation was also conducted on 10 addition (randomly selected) interseeded, renovated tracts during post-treatment intervals from 1987 through 1990. A herbicide application to reduce sandsage canopy cover was implemented by management personnel in spring 1985 within a 83.3-ha site in the east central portion of the Tamarack Prairie (Fig. 1). An aerial applicator was contracted to apply 0.84 kg/ha of 2,4-D low vol with 18.7 £/ha of water (0.75 Ib/ac of �herbicide in 2 gal of water) plus a wetting agent in 18.3-m wide strips at 36.6-m wide intervals (50% cover) during the bloom state of ~andsage (early Jun). The site, containing varying moderate to high densities of sandsage, was gridded and 12 random points under the center of the spray plane path were selected for vegetation sampling: At each of the 12 points, a transect was marked to obtain 8 36-point frame samples at I-m intervals . .In summer 1986, 38 transects, that contained nearly pure stands of prairie sandreed and sand b1uestem, distributed among 1984, 1985, and 1986 burns, their controls, 1985 revegetation strips, and 1986 renovation (interseeded) strips, were sampled. At each transect, percent seeded status was evaluated by ocular estimate. In addition, 12 height measurements and 12 HDI's were obtained within stands of both grass species. Residual grass-forb and sand sagebrush were sampled along 27 transects within grazed pastures primarily south of the Tamarack Prairie during early spring 1989 using height-density procedures. Stratification among pastures was used to insure that all pastures were included. Starting points of transects along accessible vehicle trails within, or adjacent to pastures were selected based on odometer readings derived from a random numbers table. All transects began at least 50 m from fencelines. Direction of transects was away from fencelines, if present, or randomly selected if a fence was not present. Walk-in traps (Schroeder and Braun 1991) were placed on leks near the Tamarack Prairie in early April 1989 and 1990 to trap greater prairie-chickens, plains sharp-tailed grouse, and hybrids of the 2 species. Trapped birds were marked with numbered aluminum leg bands and color-marked with plastic bandettes. Poncho-mounted, solar powered (1989) and battery-powered (1990) transmitters were placed primarily on females, but also on males, resident in the area. Additional males trapped on leks were banded and released. Four males and 4 females were radiomarked among 23 prairie chickens trapped in Yuma County and released on the Tamarack Prairie in April 1990. RESULTS Environmental Conditions Preciuitation and Phenology -- Above average precipitation in 1983 influenced the quality of residual vegetation in spring 1984. Annual precipitation was below the long-term average (approximately 41 cm) during 1984, 1985, and 1988 and was above average during 1986, 1987, 1989, and 1990 (Fig. 2). Wide monthly fluctuations and varied amounts within different parts of the Tamarack Prairie occurred during the study. The automatic recorders did not effectively document differences due to occasional problems with rodents, deer, batteries, etc. Most precipitation was received during the growing season with peak moisture occurring during May and June (Table 2). �148 _ x JAN-MAR ~APR 84 ~MAY ~JUN 85 a: w t2SJ JUL L2J AUG CSJ SEP l1li OCT-DEC 86 <C >- 87 88 89 90 o 5 10 15 20 25 30 35 40 45 50 55 PRECIPITATION (CM) Fig. 2. Monthly and annual precipitation (cm) from 1984 through 1990 in relation to the long-term mean, Tamarack Prairie, Colorado. �Table 2 •. Annual precipitation (em) from 1983 to 1990 and the long-term mean (IT Colorado. K) on Month the Tamarack Prairie, IT-K" 1983 1984 1985 1986 1987 1988 1989 1990 Jan 0_81 0.13 1.19 1.19 0.20 0.41 3.00 1.37 2_79 Feb 0.89 0.15 2.84 0.33 2_36 5.26 0.30 1.27 0.13 Mar 1.98 9.25 1.68 0.97 1.37 3.05 2.67 0.76 3.43 Apr 5.13 3.96 8.69 5.69 10.01 1.60 3.28 1.83 3.89 May 6.48 6.35 5.11 6.32 6.45 12.55 13.77 4.06 5.99 Jun 6.40 14.78 7.11 2.08 7.62 7.75 4.22 8.99 2.97 Jul 5.31 5.59 1.24 9.60 2.90 6.32 9.88 3.71 13.28 Aug 5.18 3.28 1.68 2.11 3.89 5.84 1.75 7.90 6.53 Sep 3.48 0.08 1.12 3.61 5.33 2.41 2.87 3.66 5.21 Oct 2.51 1.55 3.53 0.94 5.16' 1.17 0.10 0.56 2.67 Nov 1.12 5.50 0.03 2.69 1.09 3.12 0.33 0.33 3.30 Dec 1.25 1.01 2.03 3.05 1.12 2.11 0.32 0.59 0_00 40.54 51.61 36.25 38.58 47.50 51.59 42.49 35.03 50.19 Totals "tong-term (44 year) means, 1983, and data for winter months were obtained from U. S. Weather Service records. Spring temperatures, which influenced vegetation growth and conditions at time of prescribed burns, averaged above the long-term mean each all spring except 1984 (Fig. 3). Average temperatures .in March and/or April especially, were frequently above normal. Plant phenology on 1 May reflected accumulated (MarApr) temperature departures from the long-term average (Fig. 3). Warm-season grasses had not yet emerged at the time of the 4 May 1984 burns during an especially cool spring (Fig. 3, Table 1). In contrast, needle-andthread was already heading and prairie sandreed was about 30 cm tall when burns were conducted on 16 May 1985. Plant phenology was approximately 3 weeks earlier in 1985 than during the previous spring. Spring 1986 phenology was slightly in advance of that in 1985 and warm-season grasses had started growth when burns were initiated on 23 April. Weather factors prevented completion that day and most of burn 1 in 1986 was completed on 30 April. Plant phenology in spring 1987 was slightly behind that of the previous spring primarily because of below average temperatures in March (Fig. 3). Several hard freezes in mid to late April 1988 and on 1 May 1989 (accompanied by prolonged dry weather) retarded vegetation growth in relation to average temperatures. Phenology in spring 1990 was similar to that of preceding years. �1)U _MAR X ~ APR 84 ~MAY 85 ~JUN c: 86 -c w >- 87 88 89 90 o 5 10 15 20 25 30 35 40 45 50 55 TEMPERATURE (F) Fi~. 3. Monthly average temperatures (OF) from March through June, 1984-90 in relation to the long-term mean, as an index to vegetation phenology, Sterling, Colorado. �1.'::>1. Soil Moisture -- Little soil moisture was stored from one year to the next within rangelands. Native range vegetation used available moisture as late as October. Most winters were relatively dry (Fig. 2) and not conducive to major soil moisture accumulation. Therefore, precipitation received during the spring - early summer growing season was the primary determinant of annual growth. Cool-season grasses (needle-and-thread and western wheat [Agropyron smithiil) grew well during years with favorable winter and/or early spring moisture, whereas warm-season species were most benefitted by above average May through July rainfall. Soil probe samples (Table 3), obtained primarily in April and May (1985-90), revealed a close relationship with winter-early spring precipitation patterns (Fig. 2) among years. Winter and early spring moisture accumulated in the soil. However, as spring growth advanced, depletion of soil moisture accelerated. Most favorable accumulations occurred in spring 1986 through 1988; whereas, deficient precipitation in spring 1989 was evident (Table 3). Dry soils at or near the surface usually prevented sampling during summer. Table 3. Soil probe depths (dm) as an index to available soil moisture within the Tamarack Prairie, northeastern Colorado, 1985-90. ·SE Year Date Sample size X depth 1985 22 Apr 17 May 5 Jun 86 26 20 6.66 10.92 11.91 0.19 0.34 0.73 1986 4 7 19 30 Apr May May May 21 11 8 13 12.19 17.17 18.16 16.20 0.65 0.38 0.08 0.65 1987 1 Apr 29 Apr 6 May 2 Jun 2 Jul 32 28 16 16 17 12.04 9.86 12.86 11.21 7.32 0.23 0.32 0.47 0.42 0.49 1988 4 18 27 4 22 Apr Apr Apr May May 16 16 16 16 16 9.76 8.99 10.37 12.73 13.43 1.02 0.63 0.74 0.49 0.46 1989 12 2 15 31 9 Apr May May May Jun 16 16 12 16 16 4.13 4.48 4.89 5.24 6.30 0.16 0.22 0.51 0.40 0.45 1990 2 Apr 30 Apr 24 May 16 16 16 9.16 9.76 8.21 0.69 0.64 0.52 �152 Height-Density Sampling Within Burned Sites Height-density indices (HDI) sampled standing residual vegetation in late winter or early spring prior to significant growth of new vegetation. Therefore, they reflected the previous year's growth and the vegetation's ability to remain standing during the subsequent fall and winter. The 2 burns conducted in 1984 (burn 1-84 and burn 3-84, Fig. 1) were separated for analysis because of apparent site differences in soil, vegetation, and precipitation that affected HDI. The 1985 and 1986 sites possessed similar soils, vegetation, and precipitation, and trends were similar. Therefore, initial analyses were conducted separately, but data were combined for additional analysis (ignoring year; paired ~ of differences between treatments and controls) using the 6 site means. Grass-forb HDI -- Prescribed burns conducted in May 1984 on sites 1-84 and 384 reduced the height-density quantity of residual grass-forb vegetation in spring 1985 (f < 0.001) and subsequent years (Fig. 4, Tables 4 and 5). Grassforb residual within burn 1-84 recovered by 1987; that within burn 3-84 by 1991. Possible reasons for slower recovery in burn 3-84 include greater density of sand sagebrush (which resprouted rapidly and may have suppressed grasses), a fire that was more intense and potentially more damaging, poorer quality soils, and less rainfall during 1984. Grass-forb HDI's increased dramatically in 1988 from previous years within the burned and control transects on both burns (Fig. 4). Prescribed burns in 1985 also reduced grass-forb HDI through the first growing season (Tables 6 and 7, Fig. 4, f < 0.001). However, in contrast to the 1984 burns, grass-forb HDI recovered by the end of the 2nd growing season within the 1985 burns and exceeded the controls by the end of the 3rd year (f < 0.001). It remained high through the 4th year before fire enhancement was negated (Fig. 4). Departures of HDI means in 1991 were believed a result of error due to reduced sample size. Within the 1986 burns, grass-forb HDIs were not markedly suppressed following the first post-treatment growing season (f > 0.05) and exceeded controls by the end of the 2nd post-treatment growing season (Fig. 4, £ < 0.001). However, the enhanced growth caused by fire lasted only 1 year and was not evident in 1989 and subsequent years. �1::>,) Table 4. Height-density (dm) within burn 1-84 and controls during spring 1984-90, Tamarack Prairie, Colorado. Years Sandsage GrassLfb x x SE x SE Combined SE Burn 19848 1985 1986 1987 1988 1989 1990 0.256 0.134 0.232 0.208 0.589 0.527 0.434 0.022 0.019 0.028 0.026 0.061 0.048 0.062 0.856 0.313 0.358 0.526 0.836 0.753 1.011 0.082 0.040 0.022 0.082 0.078 0.066 0.109 0.372 0.162 0.256 0.258 0.627 0.577 0.540 0.041 0.017 0.025 0.024 0.051 0.041 0.051 0.123 0.043 0.083 0.171 0.179 0.118 0.122 0.334 0.355 0.368 0.309 0.622 0.628 0.475 0.038 0.025 0.024 0.035 0.622 0.047 0.035 Control 1984 1985 1986 1987 1988 1989 1990 0.253 0.295 0.301 0.224 0.587 0.571 0.430 0.021 0.023 0.026 0.012 0.051 0.041 0.044 0.814 0.687 0.643 0.847 1.045 1.052 0.893 F Values Pre- to post-treatment 1984-85 1984-86 1984-87 1984-88 1984-89 1984-90 8 b c d Grass-fb Sandsage Combined 47.50d 4.24 0.52 0.00 0.78 0.01 40.10d 14.98d 1.28 0.60 1.18 1.12 66.10d 10.51d 2.05 0.01 0.51 0.79 Pretreatment samples. f. < 0.050. f. < 0.025. f. < 0.001. Post-treatment Grass-fb 1985-86 1985-87 1985-88 1986-87 1986-88 1987-88 1988-89 1989-90 8.19c 0.64 . 20.39d 0.04 7.39c 0.15 1.10 0.65 Sands age Combined 8.06c 0.41 1.33 1.40 0.22 0.32 0.02 1.48 9.32d 0.01 6.73c 0.10 0.79 3.25 0.54 �154 Table 5. Mean height-density (dm) within burn 3-84 and controls during spring 1984-91, Tamarack Prairie, Colorado. Years 19848 1985 1986 1987 1988 1989 1990 1991 0.222 0.021 0.106 0.077 0.466 0.647 0.378 0.488 Combined Sandsage Grass/fb X SE 0.033 0.005 0.021 0.023 0.052 0.138 0.058 0.120 X SE 0.827 0.121 0.356 0.286 1.215 1.435 1.068 1.575 X SE 0.059 0.037 0.026 0.054 0.086 0.110 0.089 0.211 0.493 0.047 0.201 0.157 0.831 1.159 0.680 1.023 0.053 0.014 0.015 0.027 0.052 0.119 0.029 0.167 0.088 0.040 0.094 0.062 0.161 0.226 0.309 0.280 0.531 0.503 0.629 0.424 1.059 1.548 0.984 0.900 0.028 0.028 0.050 0.069 0.051 0.252 0.165 0.224 Control 1984 1985 1986 1987 1988 1989 1990 1991 0.183 0.191 0.200 0.216 0.625 0.934 0.446 0.417 0.021 0.028 0.020 0.046 0.064 0.264 0.058 0.119 0.935 0.797 1.044 0.688 1.494 1.888 1.579 1.369 F Values Pre- to post-treatment 1984-85 1984-86 1984-87 1984-88 1984-89 1984-90 1984-91 8 b C d Grass-fb Sandsage Combined 22.50d 5.96 6.62b 5.68 2.13 2.54 0.01 114.10d 35.31d 13.55c 0.85 1.44 0.88 1.18 187.00d 53.18d 9.22b 3.77 1.21 2.26 0.58 Pretreatment samples. f < 0.050. f < 0.025. f < 0.001. Post-treatment Grass-fb 1985-86 1985-87 1985-88 1986-87 1986-88 1987-88 1988-89 1989-90 2.32 2.77 2.89 4.34 1.73 0.70 0.21 0.04 Sandsage Combined 0.91 4.45 0.13 4.68 1.27 0.19 0.44 0.58 0.14 0.00 0.02 1.46 0.89 0.00 0.27 0.86 �Table 6. Mean height-density (dm) within 1985 burns and controls during spring 1985-91, Tamarack Prairie, Colorado. Burn Year 1 2 3 All Control 3 1 2 Al1 0.374 0.325 0.322 0.511 0.774 0.423 0.301 0.346 0.280 0.376 0.775 1.220 0.667 0.376 0.158 0.180 0.156 0.443 0.771 0.316 0.357 0.323 0.277 0.325 0.644 1.025 0.529 0.345 0.872 0.828 0.925 1.070 1.242 1.443 1.068 0.615 0.745 0.560 1.732 1.873 1.730 1.815 0.537 0.767 0.648 1.253 1.844 1.267 1.226 0.627 0.771 0.670 1.317 1.765 1.414 1.408 0.444 0.391 0.383 0.581 0.844 0.535 0.385 0.369 0.335 0.393 0.859 1.332 0.750 0.583 0.323 0.465 0.411 0.878 1.609 0.661 0.694 0.380 0.382 0.394 0.782 1.254 0.666 0.551 Grass-Forb 19858 1986 1987 1988 1989 1990 1991 0.507 0.138 0.419 0.780 1.081 0.542 0.604 0.381 0.119 0.472 1.028 1.297 0.552 0.526 0.180 0.053 0.244 0.667 0.850 0.315 0.663 0.379 0.110 0.~08 0.877 1.142 0.495 0.579 Sandsage 19858 1986 1987 1988 1989 1990 1991 1.008 0.417 0.523 0.938 1.313 0.688 1.500 0.679 0.342 0.591 1.167 1.582 1.050 1.000 0._642 0.438 0.769 1.144 1.385 0.955 1.853 0.744 0.388 0.672 1.125 1.446 0.914 1.438 Combined 19858 1986 1987 1988 1989 1990 1991 8 0.565 0.142 0.425 0.786 1.109 0.548 0.675 Pretreatment. 0.407 0.130 0.476 1.037 1.340 0.567 0.577 0.302 0.088 0.330 0.766 1.017 0.359 0.916 0.429 0.124 0.426 0.899 1.196 0.513 0.680 �.L)O Table 7. Height-density (dm) within 1985 combined burns and combined controls during spring 1985-91, Tamarack Prairie, Colorado. Years Sandsage GrassLfb SE X. x SE X Combined SE Burn 19858 1986 1987 1988 1989 1990 1991 0.379 0.110 0.408 0.877 1.142 0.495 0.579 0.036 0.011 0.038 0.058 0.076 0.034 0.074 0.065 0.095 0.050 0.103 0.112 0.149 0.168 0.429 0.124 0.426 0.899 1.196 0.513 0.680 0.031 0.009 0.031 0.046 0.069 0.031 0.077 0.062 0.059 0.106 0.191 0.136 0.145 0.157 0.380 0.382 0.394 0.782 1.254 0.666 0.551 0.026 0.024 0.029 0.048 0.096 0.046 0.069 0.744 0.388 0.672 1.125 1.446 0.914 1.438 Control 1985 1986 1987 1988 1989 1990 1991 0.323 0.277 0.325 0.644 1.025 0.529 0.345 0.027 0.019 0.034 0.051 0.086 0.047 0.021 0.627 0.771 0.670 1.317 1.765 1.414 1.408 F Values Pre- to post-treatment 1985-86 1985-87 1985-88 1985-89 1985-90 1985-91 Grass-fb Sandsage Combined 96.62d 1.59 7.78d 0.28 2.56 10.12d 95.85d 0.38 1.31 115.2sd 0.18 3.53 1.22 10.95d l.S9 Pretreatment samples. l < 0.050. e l < 0.025. d l < 0.001. 8 b Post-treatment Grass-fb 1986-87 1986-88 1987-88 1988-89 1989-90 1990-91 21.60d 17.29d 6.80e 0.27 1.36 9.41d Sandsage 2.71 1.47 1.53 Combined 2.02 3.04 2.43 3.15 8.7Sd 1.67 �0.7 1 E :5!.. 0.5 enz 0.4 W 0.3 :Eo07 co~~~, £; . CONTROL ~ en 0.6 ~,' z t-!- J: 0.4 C!J 0.3 jjj 0.2 J: .•....... ---I._'"""-_1.84 85 86 87 88 89 90 91 YEAR OI.....l.._.l:I;;....---'---'-_ YEAR 1-84 BURN enz w a t-!I C!J iii I 3-84 BURN '.2 1.2 1.1 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 "0 • E >o.a l- e;; Z w aU I l- ::I: 52 •.• w ::I: 0.2 85 86 87 88 89 YEAR 1985 BURN Fig. 4. , ,, 0.1 o~---~--------~--------~----84 85 88 87 88 8g go E __~_--b--~ 0.2 0.1 ~ ~ , ~ 0.5 ,, ,, ,, (!) W :J: " E 0.8 ~ ~ :J: ,~ , , ,' ,, ,,, , , , 0.9 0.6 90 91 •• •• ., •• •• YEAR 10 "' 1986 BURN Response of grasses and forbs to burning, Tamarack Prairie, Colorado. �158 Height-density was analyzed (ignoring year) using differences between site means for the 6 sites burned during 1985 and 1986. There was significant 1styear post-treatment reduction in grass-forb HOI but a significant increase in HOI by the 2nd year (Table 10). This 2nd year increase above pre-treatment levels was not evident within the 1984 burns. Sandsage HOI -- Sand sagebrush recovered more slowly than grass-forb vegetation and did not recover completely until 1990 (burn 1-84) and 1991 (burn 3-84) based on HOI (Fig. 5, Tables 4 and 5). Sage was potentially more severely impacted by the more intense fire within burn 3-84. Sage recovered more rapidly within the 1985 burns (Fig. 5, Tables 6 and 7) than within either the 1984 or 1986 burns (Fig. 5, Tables 8 and 9). Reasons for more rapid recovery subsequent to the 1985 burns are uncertain (sample sizes were small) but more favorable precipitation and cooler, less damaging headfires occurred in 1985. Fires were phenologically later than in 1984. There was no evidence that fire enhanced growth. Height-density indices derived from sagebrush obstructions were consistently higher than those for grass. Thus, it contributed to visual obstruction (HOI) in greater proportion than its composition within the study sites. Transect sample sizes for sandsage within the 1-84 burn, and the 1985 and 1986 burns were often small which increased variance. Therefore, HOI means were not as precise as those for grass-forb vegetation. �1.':>9 ~---4 ' , , , , , ,,~ 1.0 E :E. ~ enz 0.8 ~ o.e W J: e jjj J: ,, 'A_ 0.7 , ---~ ' ,, ,, , , E 1.6 CONTROL , o.s . 2.0 1.8 1.1 '0 •... CONTROL', ~1.4 en 1.2 Z w c 1.0 ,, ,, ,," ~ o m::I: 0.4 0.3 0.2 84 .•, 85 86 87 8g 88 0 go 84 85 86 87 88 89 90 91 YEAR 3-84 BURN • 1.8 1.8 ,, , ,, , , , 1.6 , ,, ,, ,, " ,, 1.6 \ 1.4 1.4 E ::E. 1.2 1.2 CONTROL I 0 ,.:.. 0.8 l: Cl W 0.6 l: 0.6 BURN 0.4 0.4 0.2 0.2..__---85 86 87 ---~-88 89 90 91 o •.....•. _-"-_-"-_-'-_-'-_-'-_-'-85 86 88 89 90 91 1986 BURN 1985 BURN of sand sagebrush 87 YEAR YEAR Response " ',/ , z w am 0.8 5. - ... _- I (i) t-!- Fig. , , ~ w 1.0 c I \ BURN 1-84 BURN enz \ 0.6 0.4 0.2 YEAR ~ ,' ::I: 0.8 0.5 -.-g , ,, to burning, Tamarack Prairie, Colorado. �160 Table 8. Mean height-density (dm) within 1986 burns and controls during spring 1985-91, Tamarack Prairie, Colorado. Burn Year 1 2 3 All 1 Control 2 3 All Grass-Forb 19858 19868 1987 1988 1989 1990 1991 0.326 0.304 0.120 0.543 0.723 0.386 0.398 0.314 0.337 0.437 1.359 1.159 0.666 0.470 0.259 0.256 0.202 0.824 1.019 0.361 0.418 0.292 0.290 0.226 0.855 0.963 0.438 0.425 0.294 0.277 0.234 0.387 0.794 0.360 0.385 0.316 0.312 0.404 0.858 1.141 0.561 0.440 0.233 0.213 0.269 0.644 1.074 0.432 0.376 0.275 0.265 0.289 0.600 0.983 0.435 0.395 0.829 0.756 0.885 1.265 1.353 1.557 1.258 0.417 0.300 0.833 1.667 1.250 1.000 1.167 0.618 0.690 0.671 1.197 1.810 1.343 1.463 0.682 0.693 0.750 1.237 1.650 1.430 1.387 0.345 0.342 0.325 0.494 0.886 0.454 0.502 0.317 0.331 0.413 0.873 1.145 0.564 0.457 0.298 0.323 0.357 0.743 1.304 0.509 0.631 0.320 0.332 0.357 0.679 1.116 0.500 0.547 Sandsage 19858 19868 1987 1988 1989 1990 1991 0.621 0.838 0.169 0.904 1.047 0.860 0.988 0.375 0.500 0.250 1.000 1.250 1.667 0.395 0.650 0.250 1.194 0.857 0.600 0.794 0.566 0.793 0.189 0.945 1.007 0.852 0.973 Combined 19858 19868 1987 1988 1989 1990 1991 a 0.421 0.470 0.127 0.616 0.815 0.486 0.567 0.315 0.339 0.434 1.355 1.159 0.473 0.498 Pretreatment years. 0.272 0.281 0.204 0.834 1.008 0.365 0.443 0.335 0.367 0.224 0.863 0.969 0.474 0.500 �Lo L Table 9. Height-density (dm) within 1986 combined burns and combined during spring 1985-91, Tamarack Prairie, Colorado. Years Sands age GrassLfb x x SE controls Combined x SE SE Burn 1985a 1986a 1987 1988 1989 1990 1991 0.018 0.023 0.039 0.092 0.067 0.052 0.027 0.292 0.290 0.226 0.855 0.963 0.438 0.425 0.566 0.793 0.189 0.945 1.007 0.852 0.973 0.066 0.098 0.046 0.122 0.086 0.085 0.111 0.335 0.367 0.224 0.863 0.969 0.474 0.500 0.020 0.028 0.063 0.087 0.058 0.050 0.029 0.064 0.054 0.080 0.210 0.204 0.147 0.115 0.320 0.332 0.357 0.679 1.116 0.500 0.5470 0.016 0.013 0.024 0.049 0.063 0.031 0.048 Control 1985 1986 1987 1988 1989 1990 1991 0.275 0.265 0.289 0.600 0.983 0.435 0.395 0.017 0.018 0.025 0.054 0.054 0.029 0.021 0.682 0.693 0.750 1.237 1.650 1.430 1.387 F Values Pre- to post-treatment 1985-87 1985-88 1985-89 1985-90 1985-91 1986-87 1986-88 8 Grass-fb Sandsage Combined 3.13 4.69b 0.51 0.41 0.19 5.26b 4.58b 28.22d 11.15d 8.45d 3.31 6.88c 0.57 1.11 8.71d 3.60 Pretreatment f < 0.050. c P < 0.025. d f < 0.001. b 26.42d 5.19b samples. Post-treatment 1987-88 1988-89 1989-90 1990-91 Grass-fb Sandsage Combined 33.88d 2.67 0.09 0.77 0.19 5.69c 10.99d 0.07 0.55 �162 Table 10. Height-density (dm) differences (1 test) among pre- and post-treatment intervals (ignoring year) within 6 sites burned in 1985 and 1986, Tamarack Prairie, Colorado. Post-treatment Interval 2 1 3 Year 4 5 Grass-forb Pretreatment 1st year post-treatment 2nd year post-treatment 3rd year post-treatment 4th year post-treatment 2.968 l. 91 7.34c l.06 2.25 l.11 2.758 0.72 0.40 l.19 3.42b 1.55 Sand Sagebrush Pretreatment 1st year post-treatment 2nd year post-treatment 3rd year post-treatment 4th year post-treatment 8.50c 8 b c 3.82b 0.25 2.738 0.96 l.32 0.07 2.07 0.50 0.28 Combined Pretreatment 1st year post-treatment 2nd year post-treatment 3rd year post-treatment 4th year post-treatment l. 76 2.728 3.108 Vegetation l.43 10.36c 0.34 l.82 0.79 l.06 l.3l 0.65 1.39 l. 91 0.12 f < 0.05. f < 0.02. f < 0.0l. Moderate fluctuation in percent obstruction occurred from year to year among the control transects (Table 11). Sampling differences among personnel, primarily in 1990, were partially responsible. Combined vegetation -- Sandsage obstructed 10 - 20% of the HDI readings within burn 1 in 1984 and within all burns in 1985 and 1986 (Table 11). Therefore, trends for combined vegetation (total HDI) were heavily weighted by grassforb, and followed grass-forb HDI trends (Figs. 6, Tables 4, 6 - 9). In contrast, about 50% of the HDI obstructions within burn 3-84 were by sandsage (Table 5), thus sage and grass-forb residual contributed equally to combined HDI (Fig. 6). �IbJ Grass-forb - Weather Relationships -- Early spring HDI's of residual grassforb (primarily grass) vegetation were impacted by previous-year growing conditions and over-winter snow accumulations. Correlations of grass-forb HDI's within controls, averaged for the 1985-86 burns, with precipitation received during (1) the previous year, (2) the previous spring and summer, and (3) the previous May-June interval showed the latter to be most closely related to subsequent HDI's (K - 0.73, l < 0.05, 5 df). When an index of average maximum snow depth was subtracted from the May-June precipitation index, the correlation coefficient increased (K - 0.82, l < 0.05, 5 df). Although both sample sizes and coefficients were relatively weak, they supported empirical observations that the relationship existed. Table 11. Percent obstruction of height-density readings by sand sagebrush within the burns and their controls, Tamarack Prairie, 1984-91. Burn 3-84 1-84 1985 1986 Treatment Control Treatment Control 51.5 13.8 18.7 15.5 11.0 38.1 50.8 4.8 21.3 15.2 15.7 13.6 38.3 44.0 7.1 20.1 6.4 14.7 15.3 7.8 48.8 50.0 9.1 20.4 9.0 12.4 1989 22.2 11.9 65.0 64.4 17.7 30.9 13.4 20.0 1990 18.3 9.7 43.8 47.5 4.3 15.4 8.7 6.6 49.2 50.8 11.8 19.1 13.8 15.3 Year Treatment Treatment Control 1984 19.4 16.7 44.8 46.3 1985 13.3 15.9 26.3 1986 12.7 12.9 1987 15.8 1988 Control 1991 Average' (controls) Overall average' among controls • All years conbined 50.1 13.7 19.4 20.9 13.5 �164 0.7 1.6 i b 0.5 A _1.4 - O.6 ! 12 ~ . ~ 1.0 Q 0.8 ffi o 0.4 !2 ~ 0.6 ~ 0.3 0 ~ 0.4 0.2 0.1 0.2 0 84 85 86 87 88 89 90 84 85 86 87 88 89 90 91 YEAR YEAR 5-84 BURN 1-84 BURN i ~ ffi Q ~ 1.4 1.2 1.2 i 1.0 - 1 ~ ffi 0.8 0.8 Q 0.6 ~ 0 0.4 0.6 ~ ~ 0.4 I, 0.2 O~----------'_~--85 86 87 88 89 90 91 '-------=---------85 86 87 88 89 90 91 0.2 YEAR 1985 BURN F.ig. 6. Response of all Colorado. vegetation YEAR 1986 BURN (combined) to burning, .- Tamarack Prairie, �16~ The HOI of grasses was suppressed by fire within all 4 burns through the 1st post-treatment growing season. However, in 1986, when May-June precipitation totaled 1.40 dm (contrasted to 1.15 dm [1984] and 0.84 dm [1985]) fire suppression seemed less severe (Fig. 7). Ouring the 2nd post-treatment growing season consistent HOI recoveries were noted. Grass-forb HOI increased 0.10 dm (burn 1-84) and 0.09 dm (burn 3-84) during 2nd post-treatment growing seasons when May-June rainfall was 0.84 dm. Grass-forb HOI increased 0.30 dm (1985 burns) when May-June rainfall was 1.41 dm; and increased 0.71 dm (1986 burns) when May-June rainfall was 2.03 dm. Post-treatment changes in grassforb HOI from the previous year within 1984-1986 burns were tested against rainfall departures from the 8-year (1983-90) mean for (1) May-June and (2) April-July intervals. The latter showed the highest correlation (I - 0.69, ~ < 0.01, 13 df). Rate of grass-forb recovery was directly related to rainfall. The same relationship was evident for sand sagebrush (Fig. 7). These data support the precipitation-snow compaction relationship with grass-forb HOI within the controls. Increased precipitation through spring intervals from 1986 through 1988 (Fig. 2) was the most logical reason for fire enhancement of grass-forb vegetation subsequent to the 1985 and 1986 burns. In contrast, below average precipitation was received for 2 years following the 1984 burns and enhanced HOI's did not occur. Trends of grass-forb HOI's within the 4 controls were similar through most of the study (Fig.8). All HOI's increased following the 1987 growing season as a result of above average precipitation. Less precipitation was received within burn 1-84 (40 dm) than within site 3-84 (49 dm) in 1988; burn 1-84 was the only site departing from the trend (Fig. 8). All HOI's declined following dry weather in 1989. Trends for sandsage HOI's within controls followed a similar pattern (Fig. 8). Similar HOI trends among controls strengthens confidence that departures among the treatments were caused by fire. Crown Cover and Composition Pretreatment sampling of crown cover was conducted in early spring 1984, prior to initiation of the spring 1984 burns. Vegetation that had grown the previous year was not easily distinguished from older residual and some forbs had deteriorated beyond recognition. This probably weakened pre- to posttreatment comparisons (the latter were conducted in mid to late summer) among 1984 burn analyses. Pretreatment samples for 1985 and 1986 burns were conducted in mid to late summer, and therefore, were more directly comparable with post-treatment data. Blue Grama (Bouteloua gracilis) -- Prescribed burning within site 1-84 provided evidence of enhancing blue grama from pre- to 1984-87 post-treatment intervals (f < 0.01, Tables 12 and 13). In contrast, no evidence of crown cover increase due to fire for the species occurred within the 3-84 burn (Fig. 9, Tables 14 and 15). Fewer transects and less blue grama/transect reduced sample sizes in the 3-84 burn. Some of the increase in blue grama may be attributed to fire removal of overs tory residual which made blue grama more visible. B~ue grama responded positively to fire following both the 1985 and 1986 burns (Fig. 9, Tables 16 through 19). Major recovery occurred during the second post-treatment growing season and extended through the 4th year within the 1985 burns (f < 0.05). Recovery occurred during the Ist>growing season within the 1986 burns, apparently because of increased precipitation that year f< 0.01). This recovery was not sustained during subsequent years. Fire �166 1.2 E 1.0 ~ 0.8 - 1985 ~ ./"' "'C en z w c 1986 f-!. C} W 0.4 ::c 0.2 ... ;"\ \ ,./ '-.,. ,,, \ \ I 0.6 -'.~.....,, ,, ,, , ..".. .... I ::c .. \ .. , o ~--~"-'--~--~--~--~--_.YR-1 YR·2 YR-3 YR-4 YR-5 YR-6 YR-7 YEAR 1.6 3-84 1.4 E -c - 1.2 ~ 1 z w c 0.8 ~ 0.6 en CJ m ::c , ~ . ... __ ..,., 1986 '...... .•.... /'....... PRE ,, , ,, <: ~/ - _, , '~ ,,, "" , 0.2 ,, , ,, .•.......... '\"\ .....:r / 0.4 0 ." ,,. 1985 ,., ~ ,, ,, 2 3 4 5 6 7 YEAR Fig. 7. burning, Recovery Tamarack of grasses and forbs (upper) and sand sagebrush Prairie, Colorado. (lower) to �167 1.2 E ~ ~ .~ ~ ._!. J: Cl w 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 J: 0.3 0.2 0.1 ------~-.---3-84 O~--~--~~--~--~~~ 84 85 86 87 88 89 90 YEAR GRASS/FORB 2.0 " 10, /j\ ".. .!/ \ .• - I· •• II ..-1 E 1.6 , \ • i/ ," .,:i ~ ,, .,h ~ , '1 UJ w 1.2 3·84 ~ J: o " 0.8 ., '.. '\ ~ .~\ . . ;.~~ 1986 . , fJ Z mJ: • ...•.. " .-.....,' " ..... . ' ""' .••..•. • ., ,. ,'l--- . , ,:... ........._198S 84 85 86 87 88 89 90 YEAR SAND SAGEBRUSH Fig. 8. Response of grasses and forbs (upper) and sand ~agebrush control plots, Tamarack Prairie, Colorado. (lower) in �168 Table 12. Mean crown cover (proportion/l-m2 x 100) for selected species, species groups, and covers within burn and control samples dtiring pretreatment (1984) and post-treatment (1984-89) intervals, burn 1-84, Tamarack Prairie, Colorado. Burn/ control Pre-tr 1984 Aug 1984 Jul 1985 Aug 1987 Jul 1989 Bouteloua gracilis B C 29.0 40.8 24.8 26.0 9.3 7.4 12.4 10.9 15.5 13.7 Stipa comata B C 20.6 15:0 6.9 14_7 8.3 10.1 10.2 12.1 17.1 19.0 Sporobolus cryptandrus B C 3.6 2.8 6.0 3.0 4.7 1.5 4.2 2.8 4.5 3.4 Calamovilfa longifo1ia B C 14.9 15.6 15.8 15.3 5.9 7.6 8.3 9.9 8.8 10.0 Andropogon hallii B C 2.3 1.7 3.8 2.3 1.3 0.8 2.6 2.0 3.4 2.4 Tall warm-season grass8 B C 17.1 17.4 19.7 17.7 7.2 8.5 10.9 12.0 12.3 12.5 Total warm-season grass B C 49.7 60.9 50.5 46.7 21.2 17.3 27.6 25.7 32.2 29.6 Artemisia filifolia B C 8.2 5.1 6.1 5.4 6.7 4.0 6.1 2.6 6.3 1.8 Perennial forbs B C 1.3 2.2 3.3 2.3 1.0 1.3 1.2 2.6 2.2 4.1 Annual forbs B C 0.2 0.1 0.3 4.0 1.3 .0.2 0.5 1.3 0.7 1.7 Bare ground B C 9.4 8.4 30.9 7.3 36.7 18.5 20.8 15.9 13.6 12.0 Dead vegetation B C 10.0 7.3 0.6 18.7 24.2 48.1 32.0 38.2 26.2 30.5 Species/category 8 Includes Ca1amovilfa, Andro:gogon, Panicum virgatum, and Pas:galum spp. �16Y Table 13. Crown cover relationships for selected species among years, burn 1-84, Tamarack Prairie, Colorado. and species groups Pre- to Post-treatment E. Value Species/catagory 1984-Aug Bouteloua gracilis Stipa comata Sporobolus cryptandrus Calamovilfa longifolia Andropogon hallii Tall warm-season grasses Total warm-season grasses Artemisia filifolia Combined perennial forbs Combined annual forbs Bare ground Dead vegetation Post-treatment 84 21. 64c 38.75c 3.61 0.32 1.46 1.06 45.54c l7.32c 8.06b 9.80c 132.70c 211. 01 c Bouteloua gracilis Stipa comata Sporobolus cryptandrus Calamovilfa longifolia Andropogon hallii Tall warm-season grasses Total warm-season grasses Artemisia filifolia Combined perennial forbs Combined annual forbs Bare ground Dead vegetation < 0.05. < 0.025. c f < 0.010. b P l 14.89c 19.26c 9.82c 5.728 1.54 3.16 10.18c 0.00 0.11 l7.22c l66.60c 87.05c 1984-87 1984-89 16.42c 22.36c 2.50 1. 32 0.02 0.64 8.48b 1. 30 2.01 4.04 10.75c 1l.16c 0.01 5.088 0.66 0.22 0.04 0.00 7.86b 3.09 1.12 2.64 0.82 5.498 to Post-treatment Aug 84-85 a 1984-85 4.24 3.37 l5.56c 7.2lb 0.02 5.558 2.58 l4.l0c 5.998 7.92b 0.82 1.54 Aug 84-87 2.72 5.178 0.16 2.56 1. 95 2.08 0.07 l3.00c 10.l9c 2.33 4.37 0.37 1985-87 0.03 0.05 1.09 0.43 0.74 0.94 0.48 3.75 6.36b 5.928 6.86b 1l.18c Aug 84-89 1.25 2.24 0.12 0.82 0.09 0.62 0.03 l6.86c 4.00 0.93 l7.23c 1. 69 �170 50 40 a:: 80 ,, , !!;! o o , 86 BURL_ / co " ,~ , 30 § 5 70 1-84 CONTROL ~ 50 z 20 Ixl § 40 Ixl 30 ...... 10 , 20 o L- PRE-84 ~ POST-84 1985 1987 10 ._. 84 1989 .•..•••• __ 85 YEAR 1984 Fig. 9. Trends ,,• , , ,,~ " , , ~_ ...... ...... ' , --"L.' 85 CONTROL "-- __ 86 .....•. _ 88 YEAR 1985-86 BURNS in cover of blue grama, Tamarack 25 Prairie, BURNS Colorado. 100 go , , , 20 ,' ,-", 1-84 CONTROL ,,~ ....• ,'.-- , 80 c: ~ 70 ;: co 8z 85 CONTROL 0 c: o / 50 Ixl 40 5 30 o ~------~------~----~------._ PRE·84 POST-84 1985 1987 1989 20 .__---~--------------~ 84 85 86 YEAR 1984 BURNS Fig. 10. Trends in cover of needle-and-thread, 88 gO YEAR 1985-86 Tamarack BURNS Prairie, Colorado. �171 Table 14. Mean crown cover (proportion/l-m2 x 100) for selected species, species groups, and covers within burn and control samples during pretreatment (1984) and post-treatment (1984-89) intervals, burn 3-84, Tamarack Prairie, Colorado. Species/category Burn/ control Bouteloua gracilis B C Stipa comata B C Sporobolus cryptandrus B C Calamovilfa longifolia B C Andropogon hallii B C Tall warm-season grass8 B C Total warm-season grass B C Artemisia filifolia B C Perennial forbs B C Annual forbs B C Bare ground B C Dead vegetation B C 8 Pre-tr 1984 Aug 1984 Jul 1985 Aug 1987 Jul 1989 13.3 10.5 7.0 7.5 2.8 2.1 5.4 4.9 7.6 5.7 10.6 13.6 l.9 7.0 4.7 4.1 6.7 1l.0 16.4 15.8 8.8 10.4 5.6 5.7 4.2 3.3 6.2 8.7 4.4 7.3 7.8 9.7 5.5 5.8 6.9 4.9 7.4 5.1 6.5 5.8 l.4 l.2 0.7 0.8 0.4 0.4 l.2 l.4 2.6 3.0 10.2 12.5 7.2 7.2 7.6 5.6 10.1 7.3 10.5 9.9 32.4 33.4 19.7 20.4 14.7 1l.0 2l. 6 2l.0 22.3 22.8 19.4 18.0 9.3 23.5 15.7 20.0 12.3 15.4 13.7 16.6 8.2 4.9 6.8 3.5 4.0 2.2 4.2 3.0 4.2 4.7 0.2 0.1 l.1 0.8 5.0 l.4 2.6 l.0 l.8 0.8 16.2 24.1 56.5 15.1 20.0 2l.9 28.8 2l.2 18.7 13.8 9.7 11.4 2.5 27.0 12.2 36.9 22.0 25.6 20.3 22.2 Includes Calamovilfa, Andropogon, Panicum virgatum, and Paspalurnspp. �172 Table 15. Crown cover relationships for selected species and species groups among years, burn 3-84, Tamarack Prairie, Colorado Pre- to Post-treatment I Value Species/catagory Bouteloua gracilis Stipa comata Sporobolus cryptandrus Calamovilfa longifolia Andropogon hallii Tall warm-season grasses Total warm-season grasses Artemisia filifolia . Combined perennial forbs Combined annual forbs Bare ground Dead vegetation 1984-Aug 84 2.29 6.78a 0.43 0.32 0.10 0.30 0.00 23.90c 2.60 0.68 280.20c 90.00c 1984-85 0.43 0.95 0.71 4.15 0.40 3.18 l.89 0.07 0.24 18.00c 94.49c 3l.81c 1984-87 l.39 2.42 9.00a 3.72 0.49 4.43 0.42 0.23 0.03 2.23 4.99 l.05 1984-89 0.01 6.22 l.65 0.52 0.36 0.44 0.02 0.18 0.39 3.31 10.70c 0.02 Post-treatment to Post-treatment Aug 84-85 Bouteloua gracilis Stipa comata Sporobolus cryptandrus Calamovilfa longifo1ia Andropogon hal1ii Tall warm-season grasses Total warm-season grasses Artemisia fi1ifo1ia Combined perennial forbs Combined annual forbs Bare ground Dead vegetation a P < 0.05. b E < 0.025. c f < 0.010. 3.23 l.53 0.30 3.55 0.07 l.95 l.81 12.10b 0.02 16.78c l.18 0.00 Aug 84-87 0.36 0.88 5.79 9.45b 0.32 7.898 0.50 14.04b 0.04 2.40 0.39 l.15 1985-87 3.16 7.088 10.42b 0.04 0.00 0.08 0.40 0.47 0.08 0.46 0.08 0.52 Aug 84-89 0.68 0.65 2.07 0.23 0.18 0.06 0.00 3.58 2.16 3.58 2.87 0.83 �173 Table 16. Crown cover (mean point-frame ta11ies/432-point transect) for selected species and species groups among pre- and post-treatment samples within combined 1985 burns and their controls, Tamarack Prairie, Colorado, 1984-90. Species/category Burn/control .1985 1986 1988 1990 Bouteloua gracilis B C 28.5 30.8 21.2 21.9 20.6 10.5 26.6 20.2 52.6 39.4 Stipa comata B C 31.4 31.3 27.7 55.2 48.2 67.2 36.2 43.1 88.8 86.4 Sporobolus cryptandrus B C 4.8 8.1 21.1 22.7 21.1 22.1 19.8 23.5 37.2 29.8 Calamovilfa longifolia B C 36.8 33.1 54.5 28.5 58.8 26.4 47.0 35.4 33.8 21.3 Andropogon hallii B C 1.7 2.1 5.1 4.1 9.6 4.6 11.2 9.1 10.1 8.8 Agropyron smithii B C 0.6 2.2 1.8 3.5 10.4 11.0 11.6 8.9 5.5 4.0 Selected warm-season B C 39.4 35.9 61.8 32.8 70.5 31.1 63.1 44.6 50.4 28.5 Total warm-season B C 72.7 74.8 104.0 77 .4 112.2 63.8 109.5 88.2 140.2 99.5 Total cool-season B C 32.1 33.5 29.5 58.7 58.6 78.2 47.9 52.0 94.3 90.4 Artemisia filifolia B C 22.5 24.7 8.2 22.6 11.9 23.8 18.0 34.6 18.5 29.1 Combined perennial forbs B C 4.4 2.9 3.4 2.1 5.7 4.2 17.5 12.7 15.6 10.6 Combined annual forbs B C 4.1 3.6 2.8 3.5 3.5 4.2 15.5 20.9 22.1 49.9 Bare ground B C 30.9 42.2 110.3 47.1 90.7 67.7 31.1 42.7 47.9 59.5 Dead vegetation B C 260.1 249.3 170.1 217.9 145.1 187.9 189.6 176.0 90.4 87.5 a Pretreatment. �174 Table 17. Crown cover relationships for selected species among years, 1985 burns, Tamarack Prairie, Colorado and species groups Pre- to Post-treatment .E Value Species/catagory Boute1oua gracilis Stipa comata Sporobo1us cryptandrus Calamovi1fa longifolia Andropogon hallii Tall warm-season grasses Total warm-season grasses Total cool-season grasses Artemisia filifolia Combined perennial forbs Combined annual forbs Bare ground Dead vegetation Post-treatment 1984-86 1984-88 1984-90 0.11 15.99c 0.46 17.11c 0.68 19.02c 18.19c 16.99c 30.01c 0.18 0.10 92.20c 32.35c 5.91b 4.708 0.64 20.77c 5.65 37.20c 41.44c 2.98 15.96c 0.19 0.34 30.10c 14.74c 4.278 0.06 1.74 0.00· 3.78 8.98c 0.14 11.35c 0.00 0.70 0.44 1.09 2.70 0.02 4.298 3.65 0.00 5.028 9.99c 0.11 3.23 0.06 3.52 0.20 0.08 1985-86 1985-88 1986-88 1988-90 8.00c 6.98b 0.07 6.02b 5.348 0.35 3.41 0.17 4.678 0.22 0.50 9.65c 5.098 0.19 1.08 13.62c 4.658 0.04 1.00 0.60 11.51c 2.98 2.14 0.00 1.41 4.178 1. 70 0.00 0.04 1. 98 4.00 0.91 2.62 0.39 2.89 0.00 0.25 1.12 to Post-treatment Bouteloua gracilis Stipa comata Sporobolus cryptandrus Ca1amovi1fa longifolia Andropogon hallii Agropyron smithii Tall warm-season grasses Total warm-season grasses Total cool-season grasses Artemisia fi1ifolia Combined perennial forbs Combined annual forbs Bare ground Dead vegetation 8 P < 0.05. b f < 0.025. c f < 0.010. 1984-85 1.69 4.938 6.96b 22.70c 9. nc 3.06 0.06 0.09 3.80 3.68 5.87b 0.06 3.60 0.06 0.00 0.68 23.2Sc 10. nc �175 Table 18. Crown cover (mean point-frame tallies/432-point transect for selected species and species groups among pre- and post-treatment samples within combined 1986 burns and their controls, Tamarack Prairie, Colorado, 1984-90. Species/category Burn/control 19848 19858 1986 1988 1990 Boute1oua gracilis B C 37.3 40.6 36.1 34.6 38.1 18.0 42.5 31.0 70.4 57.4 Stipa comata B C 42.5 28.1 40.0 52.1 38.5 61.5 38.4 48.7 65.5 88.1 Sporobolus cryptandrus B C 10.3 4.6 13.7 14.8 24.5 15.3 19.0 19.4 26.4 20.3 Calamovi1fa longifo1ia B C 26.9 39.5 25.3 33.8 44.9 37.2 45.9 54.4 38.2 47.2 Andropogon ha11ii B C 1.9 0.6 2.4 1.1 6.8 1.2 8.4 2.8 10.6 4.9 Agropyron smithii B C 4.3 1.8 9.5 5.3 10.1 4.2 3.7 1.5 Selected warm-season B C 28.9 40.1 27.6 34.9 51.7 38.3 54.4 57.6 49.7 52.1 Total warm-season B C 76.5 85.3 77.4 84.3 114.3 71.6 115.9 108.0 146.5 129.8 Total cool-season B C 46.1 29.1 44.2 53.7 47.9 66.8 48.5 52.9 69.2 89.2 Artemisia filifolia B C 18.1 14~4 16.2 19.3 7.9 22.6 14.8 29.7 16.1 24.3 Combined perennial forbs B C 7.2 5.1 4.7 3.0 15.4 6.3 25.9 11.7 6.1 7.5 Combined annual forbs B C 5.2 3.1 1.6 1.3 3.2 2.3 12.9 12.2 29.2 18.9 Bare ground B C 39.5 28.9 41.1 32.6 182.4 46.6 46.9 34.7 59.9 43.2 Dead vegetation B C 234..2 263.9 241.4 226.6 57.2 204.8 163.6 177 .0 91.0 110.3 8 Pretreatment. �176 Table 19. Crown cover relationships for selected species among years, 1986 burns, Tamarack Prairie, Colorado. and species groups E Value Pre- to Post Treatment 1985-86 1985-88 8.93c 2.59 1.14 3.01 0.28 Stipa comata 6.l4b 0.34 1.47 1.07 1.34 Sporobolus cryptandrus 8.11b 0.01 3.52 3.41 3.66 longifolia l7.00c 0.27 0.21 6.38b 0.08 7.67b 2.30 3.91 0.61 0.21 0.79 0.50 1. 74 0.48 0.00 Species/group Bouteloua gracilis Calamovilfa Andropogon hallii Agropyron smithii Tall warm-season grasses 1985-90 Post-treatment 1986-88 20.83c 1.04 0.90 8.44b 1988-90 Total warm-season grasses 28.62c 2.43 7.16c 11. 77c 1.22 Total cool-season grasses 2.33 2l.16c 0.05 1.34 2.18 3.27 6.46b 2.19 5.398 2.21 8 3.19 1. 79 0.40 0.09 0.09 0.14 0.17 1.77 Bare ground 0.15 l80.89c 1.04 2.76 13 .42c 1.33 Dead vegetation l37.04c 2.61 4.80b 3.32 2.31 Artemisia filifolia Combined perennial Combined annual a b c r. < r. < r. < forbs forbs 4.26 0.05. 0.025. 0.010. apparently increased blue grama crown cover within the 3 burns where it was abundant and increases were partially sustained through 1989 and 1990. Blue grama was one of the dominant species on the Tamarack Prairie with composition ranging from 10 to 30% among the 4 control groups (Table 20). Needle-and-thread (Stipa comata) -- Crown cover of needle-and-thread was reduced during the first growing season following fire within all sites (r. < 0.05, Fig. 10, Tables 12 - 19). This cool-season species had attained considerable growth (heading was noted in 1985) by the time burns were conducted (Table 1). First-year growth was severely repressed but extensive seed production occurred consistently during the following spring. Crown cover of needle-and-thread recovered slowly in subsequent years. The phenologically earlier burns in 1984 seemingly had a less severe impact on the species (Fig.lO), but enhancement due to fire was not evident. Precipitation and soil moisture during spring markedly influenced growth of this cool-season species. Composition within the 4 control groups averaged between 17 and 30% for this species (Table 20). It was far more abundant than other cool-season grasses, primarily western wheatgrass (Agropyron smithii, 0.1 - 3.1% composition) and sandhill muhly (Muhlenbergia pungens., 0 - 0.5% composition). �177 Table 20. Species composition (%) averaged over the interval of sampling years) within burned site control groups, Tamarack Prairie, Colorado. Catagory/species Grasses & Sedges Bouteloua gracilis Stipa comata Sporobolus cryptandrus Calamovilfa longifo1a Andropogon ha11ii Agropyron smithii Panicum virgatum Aristida sp. Paspa1um stramineum Muh1enbergia sp. Minor perennial grassesa Total perennial 3-84 1985 1986 30.67 25.43 4.74 20.19 3.23 0.35 10.11 17.12 12.02 10.76 2.28 0.01 0.39 12.86 28.79 10.67 15.94 2.79 3.10 0.04 0.11 0.09 0.06 0.01 16.51 30.20 8.46 20.91 1.10 1. 65 0.04 0.07 0.05 0.21 0.03 0.09 0.15 1.03 0.53 0.01 84.86 54.25 74.46 79.23 Annual grasses Cyperus & Carex spp. 0.37 0.50 0.01 2.13 0.16 0.31 0.09 0.75 Sage Artemisia 6.89 34.08 14.22 11.74 Cactus Opuntia grasses 1-84 filifolia sp. Perennial 0.50 1.23- 0.84 1.22 1.11 0.27 1.68 0.25 0.24 0.07 0.09 0.07 1.59 0.43 1.24 0.12 0.35 0.88 0.36 0.02 0.38 0.07 0.10 0.01 0.01 0.12 0.04 0.02 0.04 1.15 0.51 0.42 0.14 0.22 0.04 0.07 0.03 0.07 0.15 0.54 0.02 0.03 0.01 0.82 0.05 0.04 0.10 0.01 0.01 0.02 0.55 0.16 0.99 0.03 0.46 0.03 0.49 0.12 0.14 0.05 0.29 0.27 0.10 0.03 0.01 0.03 4.51 6.91 Forbs Ambrosia psilostachya Artemisia 1udoviciana Tradescantia occidenta1is Phlox andico1a Evolvu1us nutta1ianus Lathyrus po1yrnorphus Erigeron sp. Psora1ea tenuif10ra Physalis subg1abrata The1esperrna megapotimicum Sphaera1cea coccinea Mentzelia nuda Lygodesmia juncea Hap10pappus spinu10sis Penstemon angustifo1ius Allium testi1e Cichorium intybus Lesguerel1a 1udoviciana Ipomoea 1eptophy11a Minor perennial forbsb Total perennial forbs 0.01 0.01 0.01 0.03 0.02 3.07 3.44 (5 �178 Table 20 cont. Catagory/species 1-84 Annual Forbs Helianthus petiolaris Croton texensis Chenopodium album Euphorbia sp. Conyza canadensis Cirsium sp. Cryptantha sp. Eriogonum annum Amaranthus sp. Lactuca sp. Polygonum sp. Salsola kali Lepidium densiflorum Plantago purshia Other minor speciesc Total annual 0.01 0.25 1.16 0.18 0.34 8 Includes Koleria cristata, b Includes Asclepias, C Includes Froelichia, 1985 1986 0.03 0.28 0.64 0.07 0.74 0.02 0.02 0.16 0.02 0.16 0.05 1.27 0.07 3.55 0.01 0.12 0.07 0.01 0.01 0.11 0.17 0.01 0.08 0.28 1.21 0.20 1.22 0.09 0.02 0.07 0.10 0.17 0.05 3.23 0.16 0.01 0.05 2.37 1.66 6.94 0.09 0.12 0.01 0.01 forbs 3-84 Erogrostis Astragalus, 0.34 0.54 0.20 0.01 0.01 0.07 0.02 0.01 cilianensis, Cymopteris Guara, Argemone, 0.02 and Oryzopsis montanus, and Liatris spp. punctata. and other species. Sand Dropseed (Sporobolus cryptandrus) -- Fire impact on sand dropseed was not consistent among burns and it appeared least responsive among the grasses to fire (Tables 12 -.19). Some evidence of enhancement was noted within burn 184 but not within burn 3-84 (Fig. 11). No enhancement occurred within the 1985 burns but a temporary 1st-year increase was noted within the 1986 burns (f < 0.025, Fig. 11). First-year stimulation of seed production was evident. This species comprised between 5 and 12% of the total composition among controls for the 4 burns during the study interval. It ranked 4th among the dominant grasses. Prairie Sandreed (Calamovilfa longifolia) -- Comparisons from the 1984 burns are uncertain with little evidence of fire impact (Fig. 12). Crown cover was suppressed from pretreatment to 1985 (f < 0.05). Growth within 3-84 burned transects was enhanced from summer 1984 through 1987. Rainfall following the 1984 burns was not conducive to dramatic growth of this warm-season species. In contrast, phenologically later burns in 1985 and 1986, followed by increased rainfall, stimulated growth of prairie sandreed (Fig. 12, f < 0.025). Increased growth was sustained for 2 years following the 1985 burns. Second-year sampling, following the 1986 burns, was not conducted, but . increased growth occurred for at least 1 year. Fire impact was not evident by the 3rd year. Composition of prairie sandreed ranged between 11 and 21% within the burn site controls (Table 20). It ranked 3rd'among dominant grasses within the Tamarack Prairie. �12 40 10 - \ - ... \~84 ~ 8 ~ 8 - CONTROL I -. \ •... •... ···· -.~3-84 I / / 6 - ~ ..... / / ... ------~ Ixl .:fI' ~~ 2 - 1-84 CONTROL ~ •• ' " i ...... ,--- _. 20 ~ POST-84 1985 1987 .. 10 1989 ... '. ..../.~. 861:0NTROL / // ~------~----~------~----~-84 85 86 90 88 YEAR 1984 BURNS Trends . ... YEAR Fig. 11. ,\, ..•. o Ixl o~~----~------~----~------~ o PRE-84 ,----_ ..-," ,'... -----~ ,, 86 BURN , I BURN ....~ 5 85 CONTROL 30 I 1985-86 in cover of sand dropseed, Tamarack BURNS Prairie, Colorado. 20 60 16 / .•.. / .•...•.. 50 1-84 CONTROL " -, -, ~ " .~ ..~.~.':."_'~ ...: ---------- ~ 4 § 3-84 BURN ~ --- / ~ 86 BURN 40 (3 Ixl .... =r: . / I I ~~.<»> 30 3-84 CONTROL ..... .. - .. ," " ,', ~,, .•... 85 CONTROL o ~------~----~----~------~ PRE-84 POST-84 1985 1987 1989 20 ._...------~----__..------~----~-84 85 86 YEAR Trends in cover of prairie , 88 YEAR 1985-86 1984 BURNS Fig. 12. .... " .... II: sandreed, Tamarack BURNS Prairie, Colorado. , 90 �180 Sand Bluestem (Andropogon hallii) -- This tall, warm-season species, although widely distributed, comprised only I - 3% of the total composition within the Tamarack Prairie. Thus, sample sizes were small. A one-year growth increase was noted in burn 1-84, however, no increase was evident within burn 3-84 (Fig. 13). Data from the 1985 burns provided limited evidence that the species was enhanced by fire. Evidence was more positive within the 1986 burns (f < 0.025). Increased crown cover was sustained through 1990 within both the 1985 and 1986 burns (Fig. 13). Crown cover of sand bluestem declined from 1984 to 1985 following a dry growing season, but sustained increases within the controls were noted on all burns through the remainder of the study (Table 20). Selected Warm-season Grasses -- This group included prairie sandreed, sand bluestem. and minor amounts of switchgrass (Panicum virgatum) and sand paspalum (Paspalum stramineum). Trends were similar to prairie sandreed which dominated the group (Tables 12 - 19). Total Warm-Season Grasses -- This group included most of the major grasses within the Tamarack Prairie (needle-and-thread, western wheatgrass. and sandhill muhly were excluded) and comprised 37 - 59% of the total composition. Fire increased crown cover of these combined species within burn 1-84 and the increase was sustained through 1989 (f < 0.05. Fig. 14. Tables 12 and 13). In contrast. little change was noted within burn 3-84 although sample sizes were much smaller (Tables 14 and 15). Sustained crown cover increases occurred within the 1985 burns (f < 0.01. Fig. 14. Tables 16 and 17). and were also apparent within the 1986 burns (Tables 18 and 19). These data provide strong evidence that prescribed burns, especially in 1985 and 1986 benefitted combined warm-season grasses. One site. previously interseeded to 1-84. was sampled pre-treatment and growing season (1985). Analysis of switchgrass crown cover was greater. controls from pre- to post-treatment big bluestem and switchgrass within burn at the end of the 2nd post-treatment covariance revealed that bluestemwhere impacted by fire, than within intervals (F1,27 = 7.27. f < 0.05). Total Cool-season Grasses -- This group. which included western wheatgrass and sandhill muhly. was dominated by needle-and-thread and trends closely followed those for this species (Tables 16 - 19). Sandhill muhly primarily occurred within the more hilly. sandy conditions in burn 3-84. Observations indicated it was suppressed by fire. Western wheatgrass was often approaching dormancy. and therefore. was probably underrated in crown cover samples. It was least evident within burn 3-84 and most abundant within the 1985 burns and their controls (Table 20). Prickly Pear Cactus (Opuntia spp.) -- Most above-ground parts of prickly pear cactus were severely burned during the 1984 burns. It, like sand sagebrush. quickly resprouted. Based on crown cover samples. the species was suppressed and gradually recovered. Samples within the controls showed no marked trends. Fires in subsequent years were cooler and less destructive to prickly pear. Trends within burned sites were not clearly indicated. Crown cover gradually increased within the combined 1985 and 1986 controls, but not within the 1984 c9ntrols. �181 5 12 4 1.········ ,;, 10 .... 1-64 BURN ~ 8 3 ...... / / ./ 1 1 85CONTROL 1 1 ...~ --~,,/~ / ~ 52 .. Ixl ,~, - -.....••• .•••.. .~, ,, . ·.1-84 CONTRO~ '. ~ "":"-::_ ,,~. ..... ~.~ 3-84 CONTROL .~., , , /~ / ' 1... .: I·' ' .; / .' ,~ "'~ 86 BURN ..... 3-84 BURN . 2 ..•••.-./ PRE-64 POST-84 1985 1987 .;/~ 84 1984 BURNS , ~ " 90 160 , 140 cr w ffi 40 - Z 30 -.I. 8z 120 > o (J "~ a: \ ..~ 1~120 .~ "~ ~ 10 88 ~1-84CONTROL 60 o 86 Trends in cover of sand bluestem, Tamarack Prairie, Colorado. 80 ;:: 85 YEAR 1985-96 BURNS YEAR Fig. 13. 86 CONTROL o ~---~---'----~---~ 1989 '" '" '" ",""/ --- o'--'----...&.-----'----'-----'-- '" .•• S-84BURN o '-- __ PRE·84 .•..•.. \ :;:: 0 / 5100 \ , \ \ \ ..., ..•...-,-.~ ....•. ,, Ixl ... / " .... ~~·••. ·4 , '~ .•. / •• ~ --'- __ ---'~_~__ POST-84 85 YEAR 1984 BURNS / / 89 / ,~,. , , """"* , / /, 80 , , 3_.8_,~_C_O_N_T_R_'O,'_L_ 87 / ,'85 " """""- T CONTROL " 60 84 85 86 88 YEAR 1985-86 BURNS Fig. 14. Trends in cover of all warm-season grasses, Ta~arack Prairie, Colorado. 90 �182 Combined Perennial Forbs -- Trends within burns, in relation to those within controls, were variable. A 1st-year increase (f < 0.025) oc'curred in burn 184, but no similar trend for total forbs occurred within 3-84 (Fig. 15). Perennial forbs within the 1986 burns showed 1st-year enhancement (f < 0.05) which was sustained through 1990. In contrast, burns conducted in 1985 did not increase perennial forbs through 1986, but increases,were noted during 1988 and 1990 (Fig. 15). Sample sizes for individual species were generally too small to provide meaningful data. Combined perennial forbs comprised 3 7% of the composition among controls and included about 20 primary species (Table 20). There were no distinct pre- to post-treatment changes in numbers of sampled species. Several early species, including sweet pea (Lathyrus polymorphus), Psoralea spp., and Phlox andicola, had matured and nearly disappeared by mid to late summer sampling. Grasshoppers and other insects reduced the crown cover of some species. Western ragweed (Ambrosia psilostachya) and spiderwort (Tradescantia occidentalis) were the most common species (Table 20). Western ragweed, a warm-season species, showed evidence of fire enhancement within the 1985 and 1986 burns in 1988. This increase was only partially sustained in 1990. Fire impact on western ragweed was not evident within the 1984 burns. Annual Forbs -- Combined annual forbs were highly variable as to species and occurrence within both the treatments and controls among all burns. Pretreatment data for the 1984 burns were especially weak because much of the residual of annual forbs had deteriorated when sampled in early spring 1984. Fire suppressed annual forbs through the 1st growing season within burn 1-84 (Fig. 16). This trend was not evident among other burns. Annual forbs increased more within burn 3-84 than within its controls. This contrasts with trends on other burns. Annual forbs increased markedly within controls in the 1985 burns during 1988 and 1990 samples (Fig. 16). Most of the increase was attributed to 2 species; Russian thistle (Salsoli kali) and horseweed (Conyza canadensis). Similar trends were evident during 1988 and 1990 sampling within the adjacent 1986 burns; however, annual forbs in the treated sites exceeded those in the controls. When data from the 1985 and 1986 burns were combined, no evidence of fire impact on annual forbs was evident. Fire neither increased nor suppressed numbers of species. Mean composition within controls for combined annual forbs averaged < 2% (burn 3-84) to almost 7% (1985 controls, Table 20). Bare Ground and Dead Vegetation -- Removal of dead vegetation (f < 0.01) and sand sagebrush with fire dramatically increased the amount of bare ground within all burns (f < 0.01, Tables 12 - 19). More residual was removed during the earlier, more intense fires conducted in 1984 than in subsequent years. Recovery was nearly complete by late summer 1987 within the 1984 burns. Nearly full recovery occurred by late summer 1988 within sites burned in 1985 and 1986. �183 so 10 25 8 , ex: 20 § ex: ~CI o .: / 85 BURN ~ 15 ia Ixl 86 BURN ~./ 10 Ixl 2 PRE-84 POST-84 1985 YEAR 1987 - - __ - in cover -, ~', , 86 CONTROL ' --~ 85 CONTROL o ~---~---~--~---~ 1989 84 85 88 86 90 YEAR 1984 BURNS Trends - . #,-, '" Y,/' .. 5 O •......•.. ------'-----..___--_._--~ Fig. 15. ,.... •••• 5 54 1985-86 of perennial forbs, 5 50 4 40 ~ o o Tamarack BURNS Prairie, Colorado. ....,,' , , ,, 85CONTROL I 30 z :s: 86BURN...,~ , , ,, ..... ""· I ~ 20 Ixl 85 BURN.......' . -> _,. .~... _,. .';;' 10 .,./ ,'/ , o ~---_'_------'---~-~~~ PRE-84 POST-84 1985 YEAR 84 1987 Trends in cover 85 86 88 YEAR 1985-86 1984 BURNS Fig. 16. 86 CONTROL --- of annual forbs, Tamarack Prairie, BURNS Colorado. 90 �184 Sand Sagebrush (Artemisia filifolia) -- All fires reduced the crown cover of sand sagebrush (Fig. 17, Tables 12 - 19, f < 0.01). Nearly' all above-ground woody portions were destroyed by fire in 1984; most were destroyed during 1985 and 1986 burns. The 1985 and 1986 burns were cooler than those conducted in 1984 and were phenologically later in spring. Therefore, they potentially stressed sage plants more, since leafing and use of energy reserves were more advanced. Rapid first-year regrowth following burns in 1984 did not occur in 1985 and 1986. However, nearly all plants survived and had made considerable recovery by 1988. Crown cover sampling, when compared to HDI data, indicated more rapid recovery because the latter sampled the species when it was dormant. Prescribed spring burns severely impacted sandsage but did not increase mortality. Monitoring of wildfires that occurred on the Tamarack Prairie on 24 June 1985 (lightning) and 5 July 1986 (highway traffic) showed that mortality was not markedly reduced, but plants were severely stunted and recovery was extremely slow. Late August sampling indicated low survival but sampling during the subsequent spring showed 96% of the marked plants survived the 24 June 1985 burn. Late August 1986 inventory of sandsage survival within the 5 July burn showed only 14 of 50 plants (28%) had resprouted and 42 of 50 (84%) had resprouted in a location where the fire was less intense. However, as during the previous year, some plants were just beginning to sprout indicating slow recovery especially where burns were intense. Herbicide Treatment to Reduce Sand Sagebrush Aerial application of 2,4-D herbicide, applied on 6 June 1985 to alternate strips within an 80.8-ha site in the east-central part of the Tamarack Prairie, caused dramatic mortality of sandsage. Winds, which should have been nearly calm, were blowing from the south at approximately 8-13 kmjhr causing herbicide drift. The hilly terrain also prevented the spray plane from remaining close to the ground in all locations increasing drift. Precipitation was not received for several weeks following the treatment. As a consequence, nearly all of the sand sagebrush and broad-leafed vegetation within the site was killed rather than the partial strip reduction that was planned. Mortality of sandsage extended 100 m to the north of the tract and stunting of broad-leafed plants was noted for an additional 300 m. All sand sagebrush plants within established transects were killed and only 17 of 689 plants (2.5%) were alive within a walking traverse of the site in June 1986. Dead sage remained standing for several years deteriorating primarily in 1989. During early spring post-treatment HDI samples (time constraints prevented pretreatment sampling), sandsage was the primary obstruction 37.2% of the time in 1987, 24.1% in 1988, 22.7% in 1989 and 8.2% in 1990. Height-density trends within the sprayed site were similar to those within nearby site 2 and 3 controls for burns conducted in 1985 and 1986 (Tables 6 and 8). Grasses growing within dead sands~ge contributed to its HDI. Dramatic pre- to post-treatment changes in vegetation occurred within the herbicide-treated site based on crown cover sampling (Table 21). Blue grama, �25 1984 BURNS ", ..•••. ..•••. ", ", a: w > 0 ", 20 ". ",.~" o Z ~ 0 --- -. 15 ..•••. ......•.••. s-84 CONTROL ••••• ..... ..... s-84BURN ••••••• .............-........ a: w o ••••••••••_----- . . .. . . . .... ....... .-.. .... ..... CJ < a: . ",_ 10 ., w > < ~1.a4BURN -----_ .. ----_ --- 5 - 1.a4CONTROL --------III --- _ ------_ o PRE-84 POST-84 1985 1987 1989 YEAR 40 a: w > o 32 85CONTROL~ 0 Z ~ 28 0 a: o w 24 --- - - - _ _ 20 < a: ---."...""" w .""" 16 " ,,,,, ", CJ > < ,.. ,, .... .... ,,'''..... " ..... 1985-86 BURNS 36 "" . ". ". _ - - ."...""" ."...""" -. -,-, 12 ,'''' ~~ " ,. ..... •••••• ..... ~ Be CONTROL .... . ....•.•••.••... ........ .' ..' ....... .. •••••• .' .....:...~ Be BURN ' 8 84 85 86 88 90 YEAR Fig. 17. Trends in cover of sand sagebrush, Tamarack Prairie, Colorado. �186 needle-and-thread, and sand dropseed increased markedly; pra~r~e sandreed increased at a slower rate. Prickly pear (abundant in parts,of the treated area) increased steadily from 1985 through 1990. Perennial forbs were impacted both in quantity and number of species. Gayflower (Liatris sp.), a late-season species, was the only perennial forb observed on the site in summer 1985. Sweet pea was among the first to recover. Increased numbers and species were noted from 1986 through 1990, but full recovery of forbs had not occurred by 1990 (Table 21). Deficient precipitation in spring 1989 (Fig. 2) probably caused declines that year. Annual forbs were uncommon and showed trends similar to those for perennial f'orbs, Prescribed fire was applied to a 16-ha segment of the herbicide-treated site in spring 1986. Residual (grass) vegetation was reduced in early spring 1987 (HDI - 0.13 dm, f <0.05), but recovered under favorable precipitation in 1987 yielding increased HDI (1.13 dm) in early spring 1988 when compared with nearby controls (f < 0.001). Height-density indices in 1989 and 1990 gradually declined; apparently because of low amounts of precipitation. Renovation and Revegetation Treatments Renovation of Interseeded Tracts -- A site that had been interseeded in 198283 and partially burned in May 1984 was selected for renovation treatment (disked, treated with atrazine, and harrowed) in April 1986. Interseeded bluestems and switcbgrass were present within rows spaced 1.1 m apart. However, they were suppressed by between-row competition from native and annual vegetation. The objective of renovation was to stimulate growth of interseeded grasses. Sampling was conducted to document vegetation changes occurring following the 1986 renovation effort. Height-density of grass-forb residual grass-forb vegetation was suppressed during the first growing season following treatment (Fig. 18). HDI increased within the treated site during the 2nd growing season (1.55 dm); this increase was sustained through the end of the study (f < 0.05). Renovation increased the HDI quality of grass-forb vegetation. Sandsage (sparsely present) was severely suppressed by renovation. Height-density sampling of other interseeded sites that received the same renovation treatment in 1986 or 1987 confirmed that interseeded grasses were released from competition yielding markedly higher height-density indices. Pretreatment data were not obtained, but within 10 sites, the average HDI of standing residual was 2.71 dm in 1989 and 3.41 in 1990 (greater than within the initial test site). Observations indicated pretreatment HDI was similar to that within the previously renovated site « 1.0 dm). Crown cover sampling of selected species and species groups within the initial study site in late summer showed renovation increased growth of interseeded bluestems and switchgrass, even during the first season after treatment. Increases were sustained for several years (Table 22). Prairie sandreed, a deep-rooted indigenous grass, was neither enhanced nor decreased by treatment. Short- and midgrasses were suppressed and recovered slowly. Perennial forbs were suppressed but sustained limited recovery in subsequent years. �Hi / Table 21. Crown cover (mean point frame tallies/288-point transect) of vegetation and ground cover within 11 transects during pre- .(1985) and posttreatment (1986-90) spring intervals in the June 1985 herbicide-treated sandsage spray tract, Tamarack Prairie, Colorado. Vegetation/cover Pretreatment 1985 1986 Bare ground Dead vegetation Perennial grasses Boute1oua gracilis Stipa comata Sporobo1us cryptandrus Ca1amovi1fa longifo1ia Other perennial grasses Annual grasses Bromus tectorum Festuca sp. Artemisia filifo1ia (live) A. filifolia (dead) Opuntia & Echinocereus spp. Perennial forbs Ambrosia & Artemisia spp. Tradescantia occidental is Lathyrus po1ymorphus Psora1ea tenuiflora Evo1vu1us nutta1ianus Phlox andico1a Allium textile Mentze1ia nuda Leucocrinum montanum Penstemon angustifo1ius The1esperrna megapotimicum Cymopteris montanus Abronia fragrans Erigeron sp. Liatris sp. Total perennial forbs Annual forbs Croton texensis Chenopodium album Pepidium & Lesguere11a sp. Miscellaneous annual forbs Post-treatment 1987 1988 1989 1990 402 1,425 529 1,324 536 1,083 387 990 472 1,207 454 1,028 142 194 34 51 4 148 510 46 65 15 312 425 106 53 19 307 683 161 120 15 311 563 108 124 15 327 722 103 87 23 70 117 116 4 7 38 10 436 112 1 o o 4 259 287 210 201 5 124 44 50 62 83 75 97 5 1 9 77 7 6 29 22 123 17 121 12 45 107 18 114 55 6 4 2 1 6 1 1 1 6 1 1 1 6 2 8 1 1 12 8 1 1 19 1 2 2 1 3 2 1 1 11 1 223 96 154 156 76 3 24 2 1 4 1 1 4 1 9 4 1 6 6 8 3 1 178 3 �188 1.6 1.4 -E 1.2 "C ~ en Z w 0 t-!- :I: G W ~ 1 RENOVATION 0.8 0.6 :I: 0.4 0.2 0 86 87 ·89 88 90 91 YEAR Fig. 18. Response of all vegetation following grass) areas, Tamarack Prairie, Colorado. renovation of interseeded (with �189 Table 22. Average crown cover (proportion/1-m2 x 100) of selected species and species groups from pre- (1985) to post-treatment (1986-90) .intervals within tillage-herbicide renovated and control portions of a previously interseeded site, Tamarack Prairie, Colorado. Species/group 1985 1986 1988 1989 1990 36.3 13.8 6.4 1.2 39.8 11.2 6.8 l.6 47.1 13.8 9.9 2.6 48.3 12.4 12.5 4.9 22.1 10.2 19.8 3.4 24.6 8.1 20.4 1.7 33.9 8.5 27.6 1.2 32.2 9.0 35.0 2.3 1987 Tillage-Herbicide Andro~ogon/Panicum Ca1amovi1fa longifo1ia Boute1oua, Sti~a, etc. Perennial forb 13.7 11.3 17.6 1.5 24.2 12.4 5.4 0.6 Control Andro~ogon/Panicum Calamovi1fa longifo1ia Boute1oua, Sti~a, etc. Perennial forbs 16.4 10.7 17.1 2.2 16.6 10.6 16.8 1.7 E Values Andro~ogonl Panicum Calamovilfa longifo1ia Boute1oua, Perennial forbs Sti~a, etc. Pre-to Post-treatment 1985-86 1985-87 1985-88 1985-89 1985-90 34.688 61. 948 51. 938 28.118 42.198 1.04 2.76 2.03 3.23 1.44 62.118 66.708 38.838 30.968 34.828 1. 76 2.92 0.03 3.62 3.54 4.08 1. 78 2.87 0.34 0.04 l. 56 Post-treatment 1986-87 1986-88 1989-90 8 .r. < 0.05. l.42 �190 Revegetated Strips -- Nineteen strips were double disked (to destroy existing vegetation), treated with atrazine, harrowed, and seeded to tall, warm-season grasses in 1985. Stand establishment, primarily switchgrass, ranged from sparse to moderate. Height-density sampling of residual within 12 of 19 strips was not conducted in spring 1986, but HOI would have approximated 0.5 dm. Favorable precipitation and herbicide suppression of annual forbs prompted rapid growth of seeded grasses. The HOI in spring 1987 (after the 2nd growing season) was 1.83 dm and standing residual peaked in 1988 and 1989 at over 4 dm (Fig. 19). Comparisons with grass-forb HOI within nearby controls (for 1985 and 1986 burns) show marked contrast from 1987 through 1991. Late summer point-frame sampling documented gradual decreases in bare ground and dramatic increases in tall, warm-season grasses (Table 23). Prairie sandreed was not destroyed by treatment. Seeded species seldom established where it occurred. Few other grasses survived the treatment. If they did, they were suppressed by seeded tallgrasses. Little pronounced change occurred among other vegetation. Revegetation in subsequent years often yielded dense stands of switchgrass that did not obtain the tall, vigorous growth occurring in sparse to moderate stands.' However, height-density values remained greater than those in adjacent native range. Sampling in late summer 1986 of indigenous pra1r1e sandreed and sand bluestem within revegetated strips showed tillage released them from competition and stimulated growth. Extensive production of seed heads was noted and mean height for both averaged about 1 m, over twice that on untreated controls. �1'::11 5 -- 4 E "C ~ en Z w 3 SWITCHGRASS ~ C I I-- ::I: C!J 2 w ::I: 1 o ~------~----~----~----~----~86 87 88 89 90 91 YEAR Fig. 19. Response of all vegetation to revegetation, Tamarack Prairie, Colorado. �192 Table 23. Crown cover (mean point tallies/144-point transect) among vegetation groups from 1985 through 1990 within 12 1985 revegetation transects, Tamarack Prairie, Colorado. 1985 1986 1987 1988 1990 Bare ground 805 812 278 120 107 Dead vegetation/litter 212 156 372 620 394 Dominant 217 226 183 98 138 79 37 21 13 14 311 475 833 829 850 6 10 8 15 14 22 12 2 20 14 76 0 31 13 197 Vegetation/category native grasses Lesser grasses Seeded tall grasses Sandsage Perennial Annual and sedges and cactii forbs forbs Comparison of HDI's Among Grazed, Ungrazed, and Treated The mean HDI for residual grass-forb vegetation in transects in grazed pastures, south of the Tamarack = 0.028, n - 719). Sandsage obstructed 361 (33.4%) a mean HDI of 1.030 dm (SE = 0.063). The mean for (SE - 0.053). Sites early spring 1989 among 27 Prairie, was 0.160 dm (SE of 1,080 samples yielding combined data was 0.451 dm Within grazed sites, residual grass-forb vegetation was much lower than within either burned sites or ungrazed controls (Fig. 20). There was less contrast among sand sagebrush samples, however, that within grazed pastures remained lower. The dramatically greater HDI's for renovated and revegetated grasses is evident. Wildlife Use of the Tamarack Prairie Greater Prairie-chickens -- Releases of greater prairie-chickens (transplanted from Yuma County) were conducted on the Tamarack Prairie in 1984 (36), 1985 (40), and 1990 (23). Only 1 male was found near the Tamarack Prairie during a pretransplant search for leks. Five leks with 1 to 7 males were found in grazed rangelands adjacent to the Tamarack Prairie in spring 1985. Numbers of leks and males have slowly, but steadily, increased since then, primarily south of the Tamarack Prairie (Fig. 21). An active lek, containing several males, established about 150 m south of the Tamarack Prairie in 1987, was trapped during spring 1989, but was abandoned by all males but 1 for unknown reasons in spring 1990 and was not used in 1991. Two males were subsequently observed using a mowed lek about 1 km north within the Tamarack Prairie. The �4.5 GRASS 4 "E -c '-' > Ien Z W 3.5 3 III SAGE TOTAL ~ 2.5 C I I- J: G 2 J: 1.5 W 1 0.5 o PRIV BURNS CONT RENOV REVEG VEGET A TION TYPE Fig. 20. Vegetation response by treatment (and control), Tamarack Prairie, Colorado, 1984-90. �194 R49W-R48W ~ .skW V -"'" 13 ~* rrAMAl ~CKP J{AlRIE ~ 19 ~ ~ ~ 13 R48W-R47W ~ M* '--- 19 23 *9 ~25 ~ Z ~ 35 -. :c 0 E-< 31 ~ 25 27 29 , ~ 33 ~ 35 31 .. 2 z 0\ E-< 5 1 1 3 *16 11 7 8 9 * 14 ~ 0 ...J 11 ROAD 46 13 13 LEGEND *LEK# ~~~I~~~3·1KM o 1 SCALE Fig. 21. Colorado. Location ~ ~ of greater prairie-chicken 2rni. leks, Tamarack Prairie, 0 u l't ~ 812 Ul CI) �mowed lek was not used in 1991 but a new lek with several males was found 200300 m away, within a site previously burned by wildfire. At. least 2 hens, among 1990 transplants, nested and reared broods within the Tamarack Prairie. Nesting efforts there, by wild radio-marked hens, were unsuccessful. Monitoring of radio-marked greater prairie-chickens, trapped on leks south of the Tamarack Prairie in 1989 and 1990, indicated that hens were not strongly attracted to the ungrazed Tamarack Prairie for nesting possibly because of distances involved. Grass-forb HDI's were significantly greater there than in grazed rangelands to the south (Fig. 20), however, those for sandsage were not. All but 1 of 15 nests found during 1989-90 were associated with sandsage and most were within 1 km of established leks. Observations of greater prairie-chickens have gradually increased within the Tamarack Prairie; most occurring in the southeast part of the property (Fig. 21). Little use has been noted within the more narrow, western part of the property based on both monitoring and observations. Use of ungrazed rangelands between 1-76 and the South Platte River bottom to the north (Fig. 21) was not noted during the study. Only an occasional sighting in that area, primarily during winter, has been reported. Limited monitoring of radio-marked grouse, primarily in 1990, showed most shifted south from the Tamarack Prairie toward grain fields in fall. Birds present at lek 1 during spring 1990 were observed flying out of sight to the south, apparently to grain fields. Limited monitoring and observations within the Tamarack Prairie also suggested that hens were concentrating along mowed trails and other disturbed sites to feed. More detailed accounts of radiomarked greater prairie-chicken activities and use of the Tamarack Prairie were previously reported (Snyder 1990Q, 1991). Plains Sharp-tailed Grouse -- This species has been observed sporadically during winter months along the Tamarack Prairie or along the nearby South Platte River in recent years. Three males were observed displaying on greater prairie-chicken leks in spring 1989. Several males and 2 hens were associated with several leks in 1990. One hen, radiomarked and monitored, nested successfully and reared a brood. Surveys in 1991 showed continued increases and several males were found on a newly established lek within the Tamarack Prairie. In addition, the Tamarack up to 4 hybrids of the 2 species were observed Prairie in 1990 and 1991. on a lek south of Other Wildlife -- Horned larks (Eremophila alpestris), lark buntings (Calamospiza rnelanocorys), western meadowlarks (Sturnella neglecta), mourning doves (Zenaida rnacroura), and grasshopper sparrows (Arnmodramus savannarum) were common summer avifauna. Cassin's sparrow (Airnophila cassinii) were present but not abundant. One or more pairs of upland plovers (Bartramia longicauda) were inconsistent occupants, primarily during years when burns were conducted. Ring-necked pheasants (Phasianus colchicus) were present in low numbers «12) and mallards (Anas platyrhynchos) occasionally nested on the site. Swainson's hawks (Buteo swainsoni), red-tailed hawks, (~. jamaicensis), kestrels (Falco sparverius), and great-horned owls (Bubo virginianus) were among raptors observed on the property but nest locations were not available for these species. Only 2 jack rabbits (Lepus spp.) were .observed and there was little evidence of desert cottontails (Sylvilagus audubonii). Pocket gophers, (Geornys sp.) thirteen-lined ground squirrels (Sperrnophilus tridecernlineatus), and kangaroo rats (Dipodomys sp.) were common rodents, and �196 undoubtedly the primary food for resident coyotes (Canis latrans). Only occasional evidence of badgers (Taxidea taxus) and striped skunks (Mephitis) was noted. Mule deer (Odocoileus hemionus) and white-tailed deer (Q. virginianus) were common at all times of year, whereas pronghorn (Antilocapra americana) used the site inconsistently. A few other wildlife species occasionally passed through the property. DISCUSSION This study examined several aspects of range manipulation and management with enhancement of habitats for greater prairie-chickens as the underlying theme. Kirsch (1974) stated that quality of nesting and brood-rearing habitats appears to be the universal limiting factor for prairie-chickens through their range. Management and evaluations were based on that assUmption. The primary questions asked at study initiation were: will prescribed burning increased the quality of standing residual grass to enhance nesting cover for prairiechickens? Will burning increase the quantity of tall, warm-season grasses, which usually possess better ability to remain standing over winter (Duebbert et al. 1981)? Will burning thin dense stands of sand sagebrush which are present only within this western edge of the greater prairie-chicken's range? Little information concerning the impact of fire on sand sagebrush was found within literature reviewed prior to this study. Grasses Prescribed burns have been used successfully to increase the composition of tall, warm-season grasses primarily within tallgrass prairies to the east where cool-season grasses commonly invade decadent stands of warm-season species, or in locations with lower precipitation/evaporation ratios than those in eastern Colorado (Kucera and Ehrenreich 1962, Anderson et al. 1970, Wright and Bailey 1980). In areas of higher precipitation, mulch increases rapidly on ungrazed range and suppresses growth of grasses so that periodic renovation is needed. Prescribed burns have been used successfully to restore grassland for prairie grouse and several species of waterfowl (Westemeier 1972, Kirsch et al. 1978) and to manage habitats for northern bobwhite (Colinus virginianus) and cottontails (McWorter and Lange 1973, Queal 1973, George et al. 1978). This study was initiated to evaluate the effect of prescribed burn management within a semiarid site considered marginal for prairie grouse. We did not know if prescribed burns could be used effectively to enhance vegetation quality within the Tamarack Prairie. A consultant (L. Kirsch) was contracted in 1983 to assess the potential. He recommended prescribed spring burning as the primary management tool (memo from L. Kirsch to R. Hopper and W. Graul, Sep. 1983). Wright and Bailey (1980) stated that evaluations of prescribed burns had not been conducted within the Central High Plains including eastern Colorado. Previous evaluations of burning were conducted on wildfires which generally occurred during dry conditions and usually were harmful. Continued review of the literature indicates little additional pertinent information has been published. A study in southcentra1 Nebraska within loam soils (Schacht and Stubbendiech 1985) is partially applicable. Other data are available from the Nebraska Sandhills (Wolfe 1972, Bragg 1978, Morrison et ai. 1986), but only Bragg's data involved prescribed burns. Soils within Nebraska sandhill studies contained higher percentages of sand than those within the Tamarack �Prairie. Interpretation of findings conducted within semiarid regions from Texas (Wright 1974h) through the Dakota's (White and Currie ~983, Engle and Bultsma 1984, Whisenant and Uresk 1989) all suggest using managed fire with caution. Findings of this study within a mixed-prairie sandhill setting of northeastern Colorado support that contention. Wright and Bailey (1980) reported that prescribed burning should not be used on shortgrass prairie except in unusual situations. Precipitation within the Tamarack Prairie is the same as that within nearby shortgrass ranges. Soil types (loamy sands vs. loams) are the primary differences. About one-fourth to one-third of the grass composition within the Tamarack Prairie is shortgrass. Grass-forb Vegetation Findings obtained on the Tamarack Prairie show prescribed burns reduced the height-density of residual grass-forb vegetation for 1 or more years on all sites. Part of that reduction resulted from removal of standing residual and was expected. Actual changes in phytomass were not sampled although crown cover sampling provided insight (Robel et al. 1970). Increased production of seed heads was noted for warm-season grasses during the first year and for needle-and-thread grass during the second growing season. If below average precipitation was received following burns, as in 1984, recovery was slow and fire did not increase the height-density quality of standing residual (Fig. 4). If above average precipitation occurred prior to and following the burn as in 1985 and 1986, grass-forb vegetation growth was more positive and height-density quality, exceeding that on the controls, was attained by the end of the 2nd post-treatment growing season. Enhancement due to fire lasted only 1 to 3 years (Fig. 4). Results indicate burns should be conducted during years of above average rainfall. This agrees with findings and recommendations of Wright and Bailey (1980), White and Currie (1983), Engle and Bultsma (1984), and Whisenant and Uresk (1989) for the semiarid High Plains. We can select years for burning when soil moisture conditions in early spring are above average. However, we can not predict post-treatment precipitation. Crown cover sampling provided insight into vegetation changes but left many unanswered questions. The 1984 burns, which were followed by below average precipitation, did not markedly enhance warm-season grasses. In contrast, burns during 1985 and 1986 stimulated increased growth of blue grama, prairie sandreed, and sand bluestem, and this growth began during the first post-burn growing season based on crown cover data. Prairie sandreed was probably the primary species contributing to increased height-density following the 1985-86 burns. Sand dropseed appeared least affected. Blue grama and sand dropseed were neither harmed nor benefitted by fire in southern mixed prairies (Wright 1974E). Needle-and-thread, which had attained considerable growth at the time it was burned, was negatively impacted during the first year, but consistently responded with dramatic seed production during the 2nd post-treatment growing season although crown cover did not increase. Kirsch and Kruse (1972) listed this species as an increaser under burning management. Time of burning undoubtedly is an important factor. Sample sizes for other grasses including western wheatgrass, sandhill muhly, sand paspalum, and June grass (Koleria cristata) were too small to detect changes. Observations indicated western wheatgrass and sandhill muhly, both cool-season species, were retarded by prescribed burns. These single-treatment burns did not change composition toward switchgrass, Indiangrass, and bluestems to any detectable extent. Sand bluestem was the only species present in more than trace amounts (except within interseeded or �198 revegetated sites) and it showed evidence of modest increase. It was increasing within the ungrazed control sites as well, especially during years of above-average precipitation. Its height-density cover value, when occurring naturally, was generally low within the Tamarack Prairie. Limited data indicate tall, warm-season species used in interseeding and revegetation efforts responded more favorably than indigenous species to prescribed burns. Thus, if these species were more prevalent within the Tamarack Prairie, prescribed burning might more effectively increase height-density of standing residual and the quality of the site for prairie grouse. Further evaluation is needed. Schacht and Stubbendieck (1985) noted that a single burn did not revert warmseason shortgrass to tallgrass prairie in southcentral Nebraska where annual precipitation averages about 30% greater than on the Tamarack Prairie. Fire increased shortgrasses. The same was evident on the Tamarack Prairie. Kirsch et al. (1978) noted that a period of restoration management may be needed before maintenance management can be practiced. Thus, revegetation, at least in small scattered tracts, may be needed to reduce blue grama and other native grasses in preference for taller species before applying prescribed burns to increase height-density within the Tamarack Prairie. Sand Sagebrush All prescribed burns severely impacted sand sagebrush but did not kill it. Height-density sampling, which occurred when the species was dormant, showed slower recovery than crown cover sampling, which occurred when the species was fully leafed. The 1984 burns were phenologically earlier than those in subsequent years, vegetation was drier, and nearly all above-ground twigs and stems were burned. Burns in 1985 and 1986 were conducted under more humid conditions, but after considerable leafing of sand sagebrush had already occurred. Sand sagebrush rapidly produced new growth after the 1984 burns. Within burn 3-84, where high densities of sage existed, it appeared to outcompete and suppress adjacent grasses following fire. Emergence of sand sagebrush was much slower following the 1985-86 burns, apparently because fire had depleted the energy reserves of sandsage. However, survival of the species approached 100% on all sites. Monitoring within sites burned by late June and early July wildfires revealed that emergence of new growth was often extremely slow, but nearly all plants survived. An initial study objective was to reduce sand sagebrush canopy cover to below 30%. It approximated such densities only within burn 3-84 and adjacent, more sandy and hilly rangelands (Fig. 1). Fire markedly reduced both the visual obstruction (height-density) and crown cover of the species and complete recovery had not been achieved by the end of the study. Percent visual obstruction of HDI's for sand sagebrush was approximately twice the percent composition obtained during crown cover sampling. This illustrates the importance sand sagebrush plays in providing concealment to pra1r1e grouse and other wildlife because of its taller lodge-resistent growth form. Aerial spraying, designed to remove up to 50% of the sand sagebrush within a . test area resulted in a 97% kill. Based on accumulated knowledge obtained during this study and previous studies (G. C. Miller pers. commun., Schroeder and Braun 1992), sage is used extensively by greater prairie-chickens for nesting and loafing protection in northeastern Colorado. It is a valuable component of their habitat. Similar findings have been ~eported where sandsage occurs within the range of lesser prairie-chickens (~ pallidicintus) �lYY (Jones 1963) and positive Cannon and Knopf (1981). Prickly correlations were found with percent sagebrush by Pear Cactus Wright (1974Q) reported that fire did not directly kill prickly pear cactus but that it injured the species making it vulnerable to attack by insects resulting in indirect kill. Prickly pear was severely burned during 1984 fires and less severely impacted during subsequent burns. Based on crown cover samples, it was suppressed by fire but gradually recovered. Spring burns did not markedly reduce the species in northeastern Colorado. It increased where competing sand sagebrush was killed by herbicides. It also increased steadily (140% from 1984 through 1990) within the 1985-86 control transects but did not increase within controls monitored for the 1984 burns. Perennial and Annual Forbs Native perennial forbs and grasses reacted similarly to fire. Cool-season species, such as wild onion (Allium textile), may be retarded by mid- to latespring burns whereas warm-season species, such as western ragweed, may be enhanced (Anderson et al. 1970, Kirsch and Kruse 1972, Mueggler 1976, Wright and Bailey 1980). Bragg (1978) found that sunflowers (Helianthus spp.) and Mentzelia nuda were adversely affected by spring fires. Early spring burns are preferable, however, wildfires under dry conditions can be injurious (Launchbaugh 1972, Wright 1974Q) and may favor annuals (Mueggler 1976). Bidwell et al. (1990) found that forbs increased when backfires, rather than headfires were used in spring and reported that backfiring small areas in late spring could be used to increase wildlife habitat. Impacts of fires on perennial forbs during this study were not clearly evident. Sample sizes were small and cool-season forbs had often matured and dried or been consumed by grasshoppers by the time crown cover samples were taken. Western ragweed benefitted from the 1985-86 burns but increases were temporary. Trends concerning fire impacts on annuals were even less apparent than for perennials. Jones (1963) noted the importance of subclimax vegetation containing forbs and higher densities of insects as brood habitat for both greater and lesser prairie-chickens. Kirsch et al. (1973) reported that prairie-chickens, like some other upland game birds, have a marked affinity for subclimax vegetation. Nesting and brood rearing habitats were considered limiting for prairiechickens throughout their range (Kirsch 1974). It was not a study objective to increase perennial and annual forbs for prairie grouse within the Tamarack Prairie, however, hindsight indicates it probably should have been. Forbs represented only a small proportion of the total composition (Table 20). Late spring head fires were not the proper management tool for enhancing most forbs. Other techniques, primarily disturbance tillage and seeding, would be needed to increase their abundance. Some species including leadplant (Amorpha canescens) still occur as remnants within nearby roadsides, but past grazing has depleted them within the Tamarack Prairie and adjacent rangelands. Such species could potentially be restored by seeding. Renovation and Revegetation Treatments Both treatments increased height-densities of standing residual. Conversions to tall, warm-season grasses, known to respond to fire in higher rainfall climates, were also achieved. These decreasers are more lodge resistent and �200 provide better residual cover for early spring nesting by pra~r~e grouse (Duebbert et al. 1981). Removal of most shallow-rooted perennial vegetation seems essential in such efforts. Direct seeding of grasses into existing stands in spring 1984 by management personnel yielded no detectable composition change. Competition of existing grasses was too great to allow new seedlings to establish and survive. Even where stands were established within interseeded furrows, adjacent vegetation quickly invaded and suppressed growth. Single treatments of atrazine herbicide were effective in suppressing annual weeds and allowing seedlings or established plants to attain vigorous growth. A 2nd application during early spring of the following year continued weed suppression and aided grass establishment. As with burning, best results occurred during years of above average rainfall. Costs/unit were greater than for burning but much greater results were obtained quickly and sustained for several more years. Based on preliminary data, future prescribed burns will be more effective, when applied to these sites, than to native grass or sagedominated sites. Findings showed tillage or sites containing indigenous effectively stimulate major renovate revegetated stands densities occur. tillage-herbicide treatments can also'be applied to stands of prairie sandreed and sand bluestem to growth. Such treatments may also be needed to of switchgrass, etc. especially when high Monitoring failed to show that interseeded tracts were used by prairie grouse within the Tamarack Prairie. Possibly, height-density qualities were too great. However, data within the literature (Miller 1963, Westemeier 1972, Kirsch 1974) tend to discount this suggestion. Monitored hens continued to use sand sagebrush for nesting and reared broods in either grazed or ungrazed native range. Prairie Grouse Occurrence on the Tamarack Prairie Prairie grouse, monitored through fall 1990 shifted toward grain fields south of the Tamarack Prairie. There they spent much of their loafing time in rangeland which was the greatest distance from windmills and least intensively grazed. It is hypothesized that if food sources had been associated with the tillage-herbicide renovated and revegetated tracts, they may have been used by grouse through fall and winter. Reasons that the Tamarack Prairie has not received greater use by pra~r~e grouse remain uncertain. Available data suggest potential benefits of providing both tillage disturbance and supplemental food sources within the Tamarack Prairie. Greater prairie-chickens visit established leks during almost all months of the year (G. C. Miller, pers. commun.). It is possible that if food sources are not available within flying distance of potential lek' sites, establishment of new leks and range expansion is less likely to occur. If leks are not present, use by hens for nesting and brood rearing is also less likely to occur. This is one possible explanation for the limited use of the Tamarack Prairie to date. Attempts to attract males to establish new leks by mowing knolls, resulted in use of one location in 1990. Truck traffic along Interstate 76 was suspected a~ another possible factor in limited grouse use of the Tamarack Prairie (Fig. 21), Traffic, while not heavy, was fairly constant. It was difficult to listen for displaying prairie grouse within 2 km of the highway due to �201 persistent truck traffic which could be heard for up to 3.2 km. Possibly, prairie grouse found this near-constant noise too competitive with their own auditory displays. Grouse use of Grazed Rangeland Monitoring of radio-marked prairie-chickens, which were trapped on private or lands managed by the Colorado State Land Board showed they usually remained there. Height-density samples taken at nest locations and at random locations within 0.8 km. failed to detect any increased vegetation quality at nest sites. Monitoring of hens showed most use occurred in lands that were not intensively grazed and contained considerable residual grass as well as sand sagebrush. Observations of rangelands in western Nebraska, where warm-season grasses are intensively grazed and sand sagebrush is lacking, show greater prairie-chickens are fairly abundant there. Height-density there was considerably lower than within sand sagebrush rangelands on and near the Tamarack Prairie. Thus, factors other than vegetation height-density appear to at least partially determine greater prairie-chicken presence and density. Annual grazing and long-term (~ 10 year) idled habitats are undesirable for prairie grouse (Kirsch 1974). Much of the Tamarack Prairie has been idled for > 10 years whereas most adjacent rangelands are grazed annually. Management for prairie grouse should be directed toward developing and maintaining vigorous subclimax grass-forb communities (Miller 1963, Kirsch et al. 1973). Thus, the future direction of management for prairie grouse on the Tamarack Prairie seems apparent. Prescribed burns on a 7 - 10 year rotation accompanied by revegetation of small tracts to native tall, warm-season grasses should be used in preference to grazing. Provision of legumes and seed producing annuals' should be evaluated. �202 Literature Cited Amen, A. E., D.L. Anderson, T. J. Hughes, and T. J. Weber. 1977. Soil Survey of Logan County, Colorado. U.S. Dep. Agric., Soil Conserv. Serv., Washington. D.C. 252pp. Anderson, K. L., E. F. Smith, and C. E. Owensby. 1970. Burning bluestem range. J. Range Manage. 23:81-92. Bidwell, T. G., D. M. Engle, and P. L. Claypool. 1990. Effects of spring headfires and backfires on ta11grass prairie. J. Range Manage. 43:209-212. Bragg, T. B. 1978. Effects of burning, cattle grazing, and topography on vegetation of a choppy sands range site in the Nebraska sandhi1ls pra~r~e. Proc. Int. Rangeland Congr. 1:248-253. Cannon, R. W., and F. L. Knopf. 1981. Lesser prairie chicken densities on shinnery oak and sand sagebrush rangelands in Oklahoma. J. Wildl. Manage. 45:521-524. Duebbert, H. F., E. T. Jacobson, K. F. Higgins, and E. B. Podoll. 1981. Establishment of seeded grasslands for wildlife habitat in pra~r~e pothole region. U.S. Dep. Inter., Fish and Wi1dl. Servo Spec. Sci. Rep. - Wi1dl. 234. 21pp. Engle, D. A., and P. M. Bu1tsma. 1984. Burning of northern mixed prairie during drought. J. Range Manage. 37:398-401. Floyd, D. A., and J. E. Anderson. 1983. A new point intercept frame for estimating cover of vegetation. Pages 107-113 in Idaho Natl. Eng. Lab. Radioecology and Ecology Programs. U.S. Dep. Energy DOE/ID 12098. George, R. R., A. L. Farris, C. C. Schwartz, D. D. Humburg, and J. M. Kienzler. 1978. Effects of controlled burning on selected upland habitats in southern Iowa. Iowa Conserv. Cornm.,Wildl. Res. Bull. 25. 38pp. Jones, R. E. 1963. Identification and analysis of lesser and greater prairie chicken habitat. J. Wildl. Manage. 27:757-778. Kirsch, L. M. 1974. Habitat management considerations for prairie chickens. Wi1d1. Soc. Bull. 2:124-129. ____________ , and A. D. Kruse. 1972. Prairie fires and wildfire. Proc. Tall Timbers Fire Eco1. Conf. 12:289-303. __________ , H. F. Duebbert, and A. D. Kruse. 1978. Grazing and haying effects of habitats of upland nesting birds. Trans. North Am. Wildl. and Nat. Resour. Conf. 43:486-497. __________ , A. T. Klett, and H. W. Miller. 1973. Land use and prairie grouse population relationships in North Dakota. J. Wildl. Manage. 37:449453. Kucera, C. L., and J. H. Ehrenreich. 1962. Some effects of annual burning on central Missouri prairie. Ecology 43:334-336. Launchbaugh, J. L. 1972. Effect of fire on shortgrass and mixed prairie species. Proc. Tall Timbers Fire Ecol. Conf. 12:129-151. McWhorter, R. E., and C. Lange. 1973. Ecology of bobwhite quail management. Unpubl. rep., Annu. Meeting Central Mtns. and Plains Sect., The Wildl. Soc. 8pp. Miller, H. A. 1963. Use of fire in wildlife management. Proc. Tall Timbers Fire Eco1. Conf. 2:19-30. Morrison, L. C., J. D. DuBois, and L. A. Kapustka. 1986. The vegetational response of a Nebraska sandhi1ls grassland to a naturally occurring fall burn. Prairie Nat. 18:179-184. �203 Mueggler, W. F. 1976. Ecological role of fire in western woodland and range ecosystems. Pp 1-9 in Use of prescribed burning in western woodland and range ecosystems, a symposium. Utah State Univ., Logan. Pusateri, F. M. 1990. Greater prairie-chicken recovery plan. Colorado Div. Wildl., Fort Collins. 24pp. Queal, L. 1973. Fire -- Tool or tyrant. Kansas Game and Fish. 30(1):7-9. Robel, R. J., J. N. Briggs, A. D. Dayton, and L. C. Hulbert. 1970. Relationships between visual obstruction measurements and weight of grassland vegetation. J. Range Manage. 23:295-297. Schacht, W., and J. Stubbendieck. 1985. Prescribed burning in the loess hills mixed prairie of southern Nebraska. J. Range Manage. 38:47-51. Schmutz, E. M., M. E. Reese, B. N. Freeman, and L. C. Weaver. 1982. Metric belt transect system for measuring cover, composition, and production of plants. Rangelands 4:162-164. Schroeder, M. A. and C. E. Braun. 1991. Walk-in traps for capturing greater prairie-chickens on leks. J. Field Ornithol. 62:378-385. 1992. Seasonal movement and habitat use by greater prairie-chickens in northeastern Colorado. Colo. Div. Wildl. Spec. Rep. 68. 44pp. Snyder, W. D. 1990g. Establishing switchgrass for wildlife in eastern Colorado. Colo. Div. Wild1., Outdoor Facts. Game Infor. Leaf. 113. 4pp. 1990Q. Sandsage-b1uestem prairie renovation. Job Progress Rep., Colorado Div. Wildl., Wi1dl. Res. Rep., Fed. Aid Proj. W-152-R. Apr.:173-202. 1991. Sandsage-b1uestem prairie renovation. Job Progress Rep., Colorado Div. Wi1dl., Wi1d1. Res. Rep., Fed. Aid Proj. W-152-R. Apr. :191-221. Vance, R. 1977. Interactions of pheasants and prairie chickens in Illinois. Pp 9 (abstract) in Proceedings Prairie Grouse Technical Council Biannual Meeting. 12: Pierre, SD. Van Sant, B. F., and C. E. Braun. 1990. Distribution and status of greater prairie-chickens in Colorado. Prairie Nat. 22:225-230 Westemeier, R. L. 1972. Prescribed burning in grassland management for prairie chickens in Illinois. Proc. Tall Timbers Fire Ecol. Conf. 12:317-338. Whisenant, S. G., and D. W. Uresk. 1989. Burning upland, mixed prairie in Badlands National Park. Prairie Nat. 21:221-227. White, R. S., and P. O. Currie. 1983. Prescribed burning in the northern Great Plains: yield and cover responses of 3 forage species in the mixed grass prairie. J. Range Manage. 36:179-183. Wolfe, C. W. 1972. Effects of fire on a sandhills grassland environment. Proc. Tall Timbers Fire Ecol. Conf. 12:241-255. Wright, H. A. 1974g. Effect of fire on southern mixed prairie grasses. J. Range Manage. 27:417-419. 1974Q. Range burning. J. Range Manage. 27:5-11. and A. W. Bailey. 1980. Fire ecology and prescribed burning in the Great Plains -- a research review. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. INT-77. Prepared by: 1tJoJd:t.J~ Warren D. Snyder Wildlife Researcher ��205 JOB PROGRESS REPORT State of: ~C~o~l~o~r~a~d~o~ Proj ect: 'Work Plan: _ 'W-167-R 21 Job: Upland Bird Research 5 Job Title: Evaluation of Habitat Quality on Conservation Reserve Lands in Eastern Colorado Period Covered: 1 January through 31 December 1991. Author: 'Warren D. Snyder ABSTRACT Monitoring of vegetation quality as nesting cover was limited to 41 fields in 1991 of the 140 Conservation Reserve Program fields normally sampled. Sampling was primarily confined to the eastern tier of strata. Vegetation height density remained the same as that obtained in 1990 during pre-greenup sampling but increased dramatically during nesting season samples, primarily _ within northeastern Colorado. Above average rainfall in May and June resulted in the increased growth. Canopy cover of perennial grass continued to ( -v . increase within sampled fields. -, ��207 EVALUATION OF HABITAT QUALITY ON CONSERVATION RESERVE LANDS IN EASTERN COLORADO Warren D. Snyder P. N. OBJECTIVES Determine distribution and quantity of Conservation Reserve Program (CRP) land in eastern Colorado in relation to distribution of selected wildlife species, evaluate the quality of vegetation on these lands for selected wildlife species, measure response of selected wildlife species to the Conservation Reserve Program using existing annual surveys, and evaluate the impact of the Colorado Division of Wildlife's cost-share program on cover quality. SEGMENT OBJECTIVES 1. Conduct evaluations of randomly selected CRP fields within eastern Colorado as part of a regional and national assessment of the Conservation Reserve Program coordinated by the National Ecology Center (NEC) of the U.S. Fish and Wildlife Service. 2. Conduct intensive visual obstruction readings (VOR) in a stratified random sample of CRP fields and proximal controls. 3. Conduct intensive visual obstruction readings (VOR) in a sample of fields cost shared by the CDOW (for enhancement of cover quality) for comparison with CRP fields not cost-shared. 4. Estimate response of selected wildlife species to the CRP based on annual population surveys. 5. Compile and analyze data and prepare annual progress report. METHODS Methods used were described by Snyder (1989, 1990). Visual obstruction readings were based on the Kirsch method of sampling rather than the procedure required by NEC personnel. The number of CRP fields sampled in 1991 was reduced to 41 (contrasted to 140 in preceding years). These were concentrated within strata 1 through 4 (within the eastern part of Colorado). It is anticipated that all fields will be sampled in 1992, the last year for field surveys. �208 RESULTS AND DISCUSSION Environmental Conditions Precipitation recorded at 9 U. S. Weather Bureau stations, distributed within eastern Colorado, fluctuated extensively among months and locations in 1991 (Table 1). Large areas within strata 1 and 2 (Fig. 1) received considerable rainfall from early May through mid June, 1991 as indicated by data from Holyoke, Akron, and Burlington. Most stations recorded average or better precipitation in July, however, it was below that received the previous year. Overall, spring"'summer rainfall averaged near or above normal in 1991 and was conducive to considerable growth of vegetation within CRP fields, especially those within the eastern tier of strata. Springfield (Baca County) did not lead in total annual rainfall for th~ first time,in ~ev~ral years based on data through the 'fiq;t 10'monthsof.199l; howeve r , it ,iike most stations in the eastern part of Colorado, received above average precipitation (Table 1). Only 3 stations, Sterling, Akron, and Rocky Ford received below average amounts. Table 1. Monthly (Jan - Oct) precipitation (in.) at 9 U. S. ~eather Bureau locations in eastern Colorado, 1991. Springfield Lamar Rocky Ford Limon Burlington Akron Greeley Holyoke Sterling Jan 0.48 0.08 0.42 0.40 0.06 0.07 0.40 0.18 0.29 Feb 0.05 0.01 0.10 0.03 0.08 0.14 T 0.28 0.11 Mar 0.84 0.93 1.45 1.79 1.27 1.11 0.34 1.54 0.66 Apr 1.13 0.99 0.80 1.40 0.41 0.84 1.21 0.87 0.17 May 1.28 1.36 0.71 1.37 2.44 4.10 2.25 6.45 2.87 Jun 2.48 3.04 1.44 1.63 4.17 2.07 2.38 3.39 2.04 Jul 3.84 1.30 2.08 3.85 5.30 3.15 2.97 1.89 1.30 Aug 1.95 6.39 0.91 6.02 1.77 1.01 0.85 0.33 2.02 Sep 2.73 1.22 1.20 0.27 1.04 0.12 1.00 1.89 2.28 Oct 0.47 0.47 0.73 0.60 1.13 0.40 0.67 1.51 0.58 Sun 15.25 15.79 9.84 17.36 17.67 13.01 12.07 18.33 12.32 14.80 13.58 10.30 12.85 14.32 14.70 11.75 16.76 14.23 Month Longterm x ,"" �209 we L 0 1 ... Fig. 1. Strata for sampling conservation reserve program fields in eastern Colorado. ~ or �210 Evaluation of Conservation Reserve Vegetation Quality Monitoring of vegetation quality was confined to the eastern tier of strata (plus 4 fields in southern stratum 4) in 1991. It included 41 fields; 23 of which had been cost shared for cover quality enhancement by the Division of Wildlife. During pregreenup sampling, height-density within stratum 1 increased over that obtained the previous year (Table 2). However, changes within other strata were less evident and the overall average changed little from 1990 (0.74 dm) to 1991 (0.73 dm). Heightdensity changes from 1990 to 1991 during summer (nesting) were much more dramatic (Table 2). Abundant rainfall received in strata 1 and 2 was reflected in markedly higher height-density indices. Changes in strata 3 and 4 were less pronounced. Table 2. Average height-density (~) indi.ces obtained from a partial sample of Conservation Reserve Program fields during pre-greenup 'and nesting intervals during 1991 compared with indices from the same fields in 1990, eastern Colorado. 11 1990 Pre-greenuE 1991 1990 1991 1 14 0.54 0.80 1.01 2.51 2 10 0.95 0.62 1.06 1.76 3 13 0.58 0.65 1.08 1.28 4 4 1.42 0.99 1.64 1.24 41 0.74 0.73 1.14 1.81 Stratum Total Nesting Average height-density during pre-greenup sampling was 0.59 dm within 18 NEC random fields in comparison to 0.73 dm within 23 CDOW cost shared fields. During the nesting season these respective indices increased to 1.14 and 1.81 dm. Perennial grass approximated 45% canopy cover during both the pre-nesting and nesting season samples (Table 3). Perennial grass canopy cover during pre-greenup increased from 24.2% (1990) to 44.2% (1991), and from 30.6% (1990) to 45.2% (1991) during nesting season. Annual vegetation declined from 1990 to 1991 within both the pregreenup and nesting seasons. During nesting season sampling, vegetation height was tallest within stratum 1 (37.7 cm) and averaged 30.1 cm among all samples. �Table 3. Canopy cover (%) of total vegetation, perennial grass, and annual vegetation, and mean vegetation height (em) within Conservatio~ Reserve Program fields during pre-greenup and nesting intervals in 1990 and 199i, eastern Colorado. Nesting Pre-greenup Variable 1990 1991 1990 1991 Perennial grass 24.2 44.2 30.6 45.2 Annual vegetation 38.2 31.4 34.7 17.2 Total canopy cover 62.4 75.6 65.3 62.4 Vegetation height 16.4 11.9 LITERATURE CITED Snyder, Y. D .. 1989. Evaluation of habitat quality on conservation reserve lands in eastern Colorado., Colorado Div. Yildl., Yildl. Res. Rep., Fed. Aid Proj. Y-152-R. Apr. 221-244. 1990. Evaluation of habitat quality on conservation reserve lands in eastern Colorado. Colorado Div. Yildl., Yildl. Res. Rep., Fed. Aid Proj. Yl52-R. Apr. 205-223. Prepared by 11l4llrAt...2 ¥ Yarren D. Snyder Yildlife Researcher or ��213 JOB FINAL REPORT State of: Colorado Project: 'W-lS2/167-R Upland Bird Research 'Work Plan: 21 Job Title: Evaluation of 'Wildlife Responses to the Conservation Reserve Program Period Covered: Author: : Job _6_ 01 January 1989 through 31 December 1991 Thomas E. Remington Personnel: Clait E. Braun, Bradley J. Parks, Thomas E. Remington, 'Warren D. Snyder, David A. 'Wilson, Colorado Division of 'Wildlife ABSTRACT Breeding birds were counted a~ong line transects within 27-39 Conservation Reserve Program (CRP) fields throughout northeastern Colorado during spring 1989-91. Densities of breeding birds were computed from counts using a Fourier series estimator. Initially, horned larks (Eremophila alpestris) were the most common and abundant breeding bird, but the percentage of fields occupied and breeding densities declined over time (11.0, 6.9, 4.0 birds/10 ha, 1989-91, respectively). Conversely, frequency of occurrence and density of lark buntings (Calamospiza melanocotys), western meadowlarks (Sturnella neglecta), and grasshopper sparrows (Ammodramus savannarum) increased over time as cover quality increased. Breeding density of lark buntings increased from 4'.0birds/lO ha in 1989 to 6.1 and 13.1 in 1990 and 1991, respectively. Meadowlarks were common in all years, but at relatively low density (1.4, 1.9 and 3.3 birds/10 ha from 1989 to 1991, respectively. Grasshopper sparrows were common and reasonably abundant (3.7, 4.0, and 6.0 birds/10 ha from 1989 to 1991, respectively). Mourning doves (Zenaida macroura) were common breeders but many probably went undetected because of their inconspicuous breeding behavior. They were found in about half the fields sampled at a density of about 1-3 birds/lO ha. Breeding birds found in a few ffelds included ring-necked pheasant (Phasianus colchicus), Cassin's sparrow (Aimophila cassinii), dickcissel (Spiza americana), upland sandpiper (Bartramia longicauda), red-winged blackbird (Agelaius phoeniceus), northern bobwhite (Colinus virginianus), and lark sparrow (Chondestes grammacus). Other birds observed were migrating (vesper sparrow [Pooecetes gramineus], white-crowned sparrow [Zonotrichia leucophtys], song sparrow [Melospiza melodia]), or nested in adjacent rangeland or shelterbelts (loggerhead shrike [Lanius ludovicianus], eastern and western kingbirds [Iyrannus tyrannus and T. verticalus]). Common breeding birds in CRP fields.were also common breeders in green wheat and/or wheat stubble. Rope drags were used to locate nests in CRP fields, green wheat, and wheat stubble. Nests of.9 species were found in CRP fields, but nests of lark buntings, mourning doves, and meadowlarks comprised 90 and 93% of all nests found in 1990 and 1991. ��215 Evaluation of Wildlife Responses Thomas .to the Conservation Reserve Program E. Remington P. N. OBJECTIVES 1. Measure and compare avian use of CRP to use of alternative (wheat and summer fallow). 2. Measure and compare nesting wheat and summer fallow. 3. Relate patterns characteristics success of birds of avian use and nest success and surrounding land uses. land uses on CRP to success in CRP fields on to cover Title XII of the Food Security Act of 1985 established a Conservation Reserve Program (CRP). The goal of the CRP program is to retire 45 million acres of highly erodible cropland from production for 10 years. Benefits of the program are primarily to reduce erosion and surplus commodities, but other benefits, such as wildlife habitat improvement, are likely (Bartlett 1987). Response by Colorado landowners to the CRP has been enthusiastic, with almost 2 million acres enrolled. The response of many wildlife agencies and personnel has been no less enthusiastic. The Colorado Division of Wildlife (CDOW) established a program to cost-share up to 70% of the landowners share of costs to establish vegetative cover under CP 1, CP 2, or CP 4. The goal of this program is to improve habitat for primarily pheasants and prairiechickens (Tympanuchus spp.). The Division's investment in this program was about $385,000. CRP tracts may benefit rap tors by providing undisturbed areas where prey bases may increase. Other birds are expected to be affected primarily through changes in quantity and quality of nesting habitat. Bird populations may change either because the quantity of nesting habitat is altered so that some segment of the population is or is not non-breeding, or because nest success changes concurrent with changes in habitat quality. Wildlife response to the CRP will depend on land-use patterns in the surrounding area, seed mixture and techniques used to establish perennial cover, vegetative response within CRP fields, species composition and densities of wildlife in the region, and many other factors. The USDA and state wildlife agencies must have information on the benefits of CRP to wildlife to plan intelligently for the future of CRP tracts after contracts expire. Without knowledgeable planning, it is likely that most CRP land will, as in previous Federal set-aside programs, return to agricultural production and any wildlife values will be negated (Bedenbaugh 1987, Leitch 1987, Cacek 1988). The objective of this study was to measure and compare avian use of CRP to use in alternative land uses (wheat and summer fallow). �216 METHODS A subset (n-68) of CRP fields randomly selected by the U.S. Fish and Wildlife Service (from the universe of all CRP fields in eastern Colorado) was randomly chosen for study. A sample (12) of fields in which the Colorado Division of Wildlife cost-shared on a wildlife grass seed mixture was added for comparison. Permission to enter and measure bird abundance within these fields was obtained via letter, and usually by telephone, from landowners. Green wheat (n-17) and wheat stubble fields (n-13) near CRP fields were also sampled. CRP, and wheat and wheat stubble fields, were sampled within an hour of sunrise to count breeding birds. A 0.8-km long transect was established near the midpoint of each field with plastic flags. An observer walked along the transect line slowly watching and listening for birds. Birds observed were identified to species and the perpendicular distance from each bird to the line transect was measured to the nearest meter using a rolotape. In 1990, each field was censused once between 20 April and 20 May and again between 21 May and 20 June to ensure both early and late breeding species were counted. Breeding bird density was estimated from perpendicular distance measures (from the higher of the 2 counts) using a Fourier series estimator (Burnham et al. 1980, 1981). Eight hectares within each CRP and green wheat or wheat stubble fields were searched for nesting birds by dragging a 30-meter long rope between 2 observers. The area around the point from which a bird flushed was searched intensively for a nest. In 1990 each field was searched 2-3 times throughout the breeding season in an attempt to document nesting by all birds using the field. Hen pheasants were captured and fitted with radio transmitters between 6 March and 23 April 1991, to evaluate extent of use and relative success of pheasant hens nesting in CRP fields. Radio-marked hens were relocated periodically through the nesting season to ascertain the cover types in which they nested and measure nest success. Hens were captured at night with long-handled nets (Snyder 1977) on or adjacent to the Turk's Pond State Wildlife Area in Baca County. Captured hens were weighed, banded, primary 1 was removed for age classification, and radio transmitters were attached. Transmitters were manufactured by either Holohil Systems (model RI-2B; 9 gms) or by Telemetry Systems Inc. (model LT1800-lSM-LD, 19 grams with poncho). Holohil transmitters were equipped with 10 cm elastic loops which were used to attach them around the neck. Telemetry Systems radios were mounted on naugehyde ponchos and fitted to each birds neck. RESULTS AND DISCUSSION Breeding Bird Study Twenty-four species of birds were observed along line transects within CRP fields, but only 6 species were common resident breeders (Table 1). Frequency of occurrence and density of birds in CRP fields varied over time as grass became established and cover quality increased. Most fields sampled entered the program in 1986 or 1987, a cover crop (sorghum) was planted in 1987 or 1988, and grass was planted in 1988 or 1989. Thus, initial censusing was of �Table 1. Density of breeding breeds observed in Conservation Reserve Program (CRP) fields, wheat fields, and wheat stubble, 1989-91, and percentage of sampled CRP fields in which birds were observed. CRP Fields Freauencv1 Species Densitv 1989 1989 1990 1991 x Horned lark Lark bunting Grasshopper sp. Meadowlark Cassin's sp. Mourning dove Vesper sp. Red-winged b1ackb. Pheasant Western kingbird Mallard Dickcissel Song sparrow Northern bobwhite "Lark sparrow Field sparrow House wren Killdeer Northern oriole American robin Loggerhead shrike Upland sandpiper ~Percentage 64 67 46 82 26 46 28 10 8 10 8 3 3 3 3 3 3 3 3 3 3 3 70 89 93 100 11 56 22 41 15 11 42 95 84 82 13 63 0 21 26 5 4 7 0 0 0 0 0 0 0 0 11 8 0 5 5 0 0 3 0 0 0 0 11.0 4.0 3.7 1.4 0.8 1.2 1990 Wheat Stubble Density Density 1991 S.D. x S.D. x S.D. x 12.0 4.7 8.4 1.3 1.7 2.3 6.9 6.1 4.0 1.9 1.3 7.9 8.7 3.2 4.0 13.1 6.0 3.3 1.3 1.9 1.1 8.3 9.9 6.0 2.3 3.5 6.4 2.8 S.D. x 16.1 1.6 1.7 S.D. 3.8 9.9 7.0 of sampled fields species was found in. N •..... -.._J �218 fields either been planted. stands. during, 1, or in a few cases, 2 growing seasons after, grass had Censusing in 1990 and 1991 was of progressively maturing grass In 1989, when cover was sparse, horned larks were the most abundant breeding bird while meadowlarks were the most ubiquitous, i.e., they occurred in the most fields (27 of 27; Table 1). Density of horned larks in CRP declined steadily and fairly dramatically as grass cover increased. Lark bunting frequency and density increased markedly from 1989 to 1991 (Table 1). In 1991 they were the most common (observed in the most fields) and abundant bird in CRP fields. Grasshopper sparrows were relatively common, especially in CRP fields with better grass and/or weedy cover. Grasshopper sparrow densities also increased markedly from 1989 to 1991 when they were the second most common and abundant bird. Mourning doves were fairly common in fields with low, sparse cover, but were probably under represented because of their tendency to display from telephone wires or elevated perches near field edges. Cassin's sparrows were commonly observed in 1989 in fields that were planted to native bunch grasses. We observed only 5 in 3 fields in 1990, and 13 in 5 fields in 1991. Fields sampled in 1990 and 1991 were primarily in northeastern Colorado where most fields were planted to smooth brome. Fields planted to bunch grasses in this area had yet to develop good stands of grass. Dickcissels were observed while singing in 1, 2, and 3 fields in 1989-91, respectively, where sweet clover was abundant. Northern bobwhite were flushed from 3 fields that either had a tree grove within the field (1 field) or bordered wooded or brushy areas,.but breeding was not confirmed. Vesper sparrows were frequently observed in late April and early May, but were not observed later and were presumed to be using CRP fields while migrating. Occasional use of CRP fields by species that nested elsewhere (in trees or shrubs) was noted. These species included lark sparrow, northern oriole (Icterus galbula), American robin (Turdus migratorius), loggerhead shrike, and eastern and western kingbirds. Green wheat and wheat stubble were also used as breeding and nesting habitat for several of these birds. Horned larks were the most common and abundant bird in green wheat and wheat stubble fields (Table 1), although estimated breeding densities may have been inflated by inclusion of some birds foraging for waste grain or insects. Lark buntings were also observed, presumably breeding, in green wheat, and to a much lesser extent in wheat stubble. Meadowlarks were commonly observed in green wheat and wheat stubble, at densities comparable to (stubble) or higher (green wheat) than in CRP fields. Grasshopper sparrows were observed in wheat stubble, but not in green wheat. Estimated densities were low relative to densities in CRP fields (Table 1). Nests of 9 species were found during searches of CRP fields (Table 2). Lark bunting nests were most frequently encountered, followed by mourning dove and meadowlark nests. In 1990 and 1991 these 3 species accounted for 90 and 93% of nests encountered in CRP fields, respectively. Horned lark, grasshopper sparrow, red-winged blackbird, Cassin's sparrow, and pheasant nests were encountered at low densities. Green wheat and wheat stubble fields were searched for nests to confirm use by breeding birds. Relatively little effort was put into these habitats when few nests were found. Ten nests were found in 12 green wheat fields searched; 2 lark bunting nests, 5 red-winged blackbird nests, and 1 nest each of horned lark, mallard CAnas platyrhynchos) and pheasant. Four nests were found in 6 wheat stubble fields searched; 3 lark bunting nests and 1 horned lark nest. �219 Table 2. Number of bird nests located during rope-drag searches wheat, and wheat stubble fields in eastern Colorado, April-June, CRP Species (N fields) Lark bunting Mourning dove Meadowlark Red-winged blackbird Grasshopper sparrow Horned lark Lark sparrow Mallard Pheasant Cassins's sparrow of CRP, green 1989-l99l. Green wheat 'Wheat Stubble 1989 (29) 1990 (29) 1991 (36) 1989-1991 (12) 1989-1991 29 12 9 2 2 10 106 60 9 4 6 5 3 177 70 23 6 3 1 2 3 3 7 1 (6) 5 1 1 1 1 The relative lack of nests in green wheat fields was surpr1s1ng. During searches for carcasses in 11 green wheat fields (sprayed with insecticides to control wheat aphids) in spring 1989 we located 6 lark bunting nests, 5 horned lark nests, and 4 mourning dove nests. Although twice as much area was searched, search methodology presumably was less likely to detect nests since, rather than drag a rope between two observers, several people walked abreast about 20 rows apart. None of these fields bordered, or were within about 10 km of any CRP fields. It seems likely that increased density of birds and nests in CRP fields over time resulted, at least in part, from birds shifting breeding activity from wheat and/or wheat stubble fields into CRP fields. The relative lack of nests in green wheat or wheat stubble in this study probably occurred because we selected fields close to, or in some cases adjacent to, CRP fields. The number of nests found for each species was not necessarily indicative of breeding density or effort. Horned larks and meadowlarks were probably under represented because, in some years, nest searching may have been conducted after the peak of nesting for these species. The peak of nesting effort by horned larks in 1989 was late May. In 1990, despite intensive searching beginning in late April, we found only 5 horned lark nests, 4 of these were apparently second nest attempts found on 14 June. Either 1989 was a relatively late year or 1990 and 1991 were relatively early years for horned lark nesting. Grasshopper sparrow nests were difficult to find because birds either ran off nests prior to flushing or didn't flush in response to the rope. Most of the 6 grasshopper sparrow nests were found when a bird flushed off the nest because we walked within 1 m. Only one pheasant nest was located in 1990, and none were located in 1991. While the quality of cover for nesting pheasants within these fields was generally poor, it was also possible that pheasant hens did not flush in response to the rope. Nest densities of mourning doves were more indicative of dove use of CRP fields than breeding density estimates from the line transects. �220 Pheasant Nest Success Fifty-one hens were captured and fitted with radio-transmitters, 29 adults (57%), 21 juveniles (41%) and 1 bird for which age could not be ascertained. Of these 51, 8 birds were judged to have lost their transmitters (6 Ho1ohi1, 2 TSI), apparently by pulling them over their heads. This was confirmed in one instance when a bird was recaptured without it's radio (TSI). Some of these may have been predated by coyotes (Canis latrans), which seldom left carcasses or evidence of predation other than chewed radios in some cases. Contact was lost with 5 radios between 2 April and 15 May. Of these, 1 juvenile disappeared at a time period when other juvenal birds were dispersing from the core winter area (mid-Apr), and may have dispersed to a location where we were unable to get a signal. The other 4 birds were likely predated, although it is possible their radios failed. Two birds disappeared 2 weeks before any known dispersal off the area, and two disappeared several weeks after dispersal had apparently ended. Radios from predated birds were frequently difficult to recover, either because they were carried long distances to the nest by a great horned owl (Bubo virginianus) (1 known radio), or more frequently because coyotes had chewed off the antenna or buried the radio. Relatively little useful nesting information was obtained because of extensive mortality prior to, and during, laying. Of 43 birds known to have retained radios, only 8 (19%) were known to have survived long enough to complete incubation. Two of these 8 hens successfully brought off young. Nesting attempts by the other 6 hens failed because of nest predation (6) or abandonment (3). Mortality was attributed almost exclusively to predation by great horned owls and coyotes, although 1 hen was struck and killed by a vehicle along the county road which transected the study area. Owls were frequently observed along Horse Creek to the north, in the trees bordering Turk's Pond on the west, and on an abandoned trailer just south of the intensive trapping area. An active coyote den was located on the north end of the CRP field where most birds were trapped. This den was within the home ranges of most pheasants wintering on the study area. Another active den was located about 1.25 miles south. Predation was extensive despite the fact that cover in this area was relatively good. About half the CRP field (that served as a focal point for most pheasant home ranges) had been planted to a wildlife mixture consisting of bunch grasses, and about 40 acres was planted with the Division cost-shared seed mixture of primarily switchgrass. The wildlife area had ample cover, including strips of unharvested wheat, blocks of unharvested alfalfa, weedy cane along the pond, and extensive willow/weed complexes along Horse Creek. Why was mortality so extensive? I believe two factors were primarily involved. Because this region is a mosaic of cropland, rangeland, and wooded creek bottoms, the density of coyotes and owls appears quite high. The imposition of CRP fields into this mosaic may have created an ecological trap for pheasants, by concentrating them in an area where coyotes denned and hunted, and an area where owls could effectively hunt. Prior to CRP, pheasant hens would likely have been dispersed throughout the area, feeding, nesting, and roosting in primarily cropland. Coyotes likely denned and hunted in rangelands, while owls nested and hunted from creek bottoms. Thus, the net effect of CRP in mixed rangeland, cropland, and creek bottom areas such as this might have been to concentrate pheasants· and predat~rs in the same fields, with inevitable consequences. �221 MANAGEMENT IMPLICATIONS The net effect of the Conservation Reserve Program on birds in eastern Colorado is not clear cut or clearly positive. This study has demonstrated that about 8 species of birds utilize CRP for breeding to at least some degree. Other species use it for foraging or hunting. The birds breeding in CRP fields, at this point in the program, primarily represent habitat generalists rather than grassland or grassland/shrub species. Green wheat fields and wheat stubble fields were used for nesting by lark buntings, horned larks, mourning doves, red-winged blackbirds, pheasants, mallards, and probably grasshopper sparrows and meadowlarks. These are also the species commonly using CRP fields. Thus, the benefits of this program, which largely replaced a wheat/wheat stubble rotation, to breeding birds are unclear. If nesting success in CRP fields is superior to success in wheat and/or stubble, then populations may have increased. It is possible however, that birds would have bred at the same density and with the same success in those fields without the CRP. Species diversity within CRP fields was not enhanced to any significant extent, primarily because vegetative structure was similar to that provided by wheat and/or wheat stubble. The utility of the CRP on pheasants can be increased. Bunch grasses, particularly switchgrass, which provide ample residual cover in spring, should be encouraged where pheasant production is a priority. Smooth brome, the predominant grass planted in northeastern Colorado, was not used by pheasants for nesting. In future signups, or if revegetation is desired, switchgrass should be encouraged to increase nest success and survival of pheasants. Pheasant survival within CRP fields can probably be increased in arid areas such as Colorado by planting food-cover patches of tall forage sorghum, particularly in fields planted to smooth brome. Woody plantings within CRP fields would enhance diversity of breeding birds. Bobwhite quail, lark sparrows, loggerhead shrikes, American robins, mourning doves, and red-winged blackbirds would be expected to use CRP (or use it more extensively) for breeding if woody plantings were present. Bunch grasses seem to provide acceptable habitat structure for the broadest range of bird species, and provide significantly better nest protection for pheasants, mallards, and other large birds. Smooth brome was an adequate cover for horned larks, lark buntings, and mourning doves, but supported only low densities of other nesting birds. �222 LITERATURE CITED Bartlett, E. T. 1987. Social and economic impacts of the Conservation Reserve Program. Pages 52-54 in J. E. Mitchell, ed. Impacts of the Conservation Reserve Program in the Great Plains. U.S. Dep. Agric., For. Serv., Gen. Tech. Rep. RM-158. Bedenbaugh, E. J. 1987. History of cropland set aside programs in the Great Plains. Pages 14-17 in J. E. Mitchell, ed. Impacts of the Conservation Reserve Program in the Great Plains. U.S. Dep. Agric., For. Serv., Gen. Tech. Rep. RM-158. Burnham, K. P., D. R. Anderson, and J. L. Laake. 1980. Estimation of density from line transect sampling of biological populations. Wildl. Monogr. 72. 202 pp. _________ , and . 1981. Line transect estimation of bird population density using a fourier series. Studies Avian BioI. 6:466-482. Cacek, T. 1988. After the CRP contract expires. Conserv. 43:291-293. J. Soil and Water Leitch, J. 1987. Policy questions from CRP in the Midwest. Pages 91-94 in J. E. Mitchell, ed. Impacts of the Conservation Reserve Program in the Great Plains. U.S. Dep. Agric., For. Serv., Gen. Tech. Rep. RM-158. Snyder, W. D. 1977. Pheasant mortality investigation. Job Final Rep., Colorado Div. Wildl., Wildl. Res. Rep., Fed. Aid Proj. W-37-R-30. Apr. :1-33. Thomas E. Remington Wildlife Researcher �223 JOB FINAL REPOR.T State of: Colorado Project: W-152-R/W-167-R Work Plan: 21 Job Title: Avifauna Responses to Grazing Period Covered: Author: Personnel: Upland Bird Research : Job _7_ 01 January 1989 through 31 December 1991 Cynthia P. Melcher C. P. Melcher and Beatrice Van Horne, Colorado State University; C. E. Braun, K. M. Giesen, C. E. Poley, T. E. Remington, and S. M. Swift, Colorado Division of Wildlife Researchers from the Colorado Division of Wildlife monitored densities of white-tailed ptarmigan (Lagopus leucurus) on Trail Ridge in Rocky Mountain National Park (RMNP) from 1966-1988. A decline in the population was detected in the late 1970s when a population increase had been expected. The decline was deep and prolonged, with no sign of recovery by spring 1989. Willow (Salix spp.), an essential food resource for ptarmigan, appeared damaged and decadent in areas where breeding densities of ptarmigan had declined most. Researchers with the Colorado Division of Wildlife hypothesized that breeding densities of ptarmigan had declined in response to habitat (willow) degradation caused by elk (Cervus elaphus) in alpinejkrummholz habitat. Densities of elk in RMNP had been controlled artificially until 1968 when the National Park Service discontinued control programs; the elk population subsequently increased significantly. Fragmentation and loss of elk habitat, extirpation of predators, and heavy hunting pressure immediately outside RMNP's boundaries may have encouraged elk to remain within the Park and increase their use of some habitat types, including alpinejkrummholz. The objectives of this study were to evaluate relationships between avian abunda,nce/species richne~s, presence of ungulates, characteristics of willow, and activity budgets/reproductive success of ptarmigan hens ·in alpine/krummholz habitats of Rocky Mountain National Park. All bird species were censused at 4 17-22 ha sites using spot-mapping techniques from 27 May to 10 July 1989, and from June 7.to 1 August 1990. Activity budgets, foraging rates, and reproductive success of 12 radio-marked hens (three at each site) were studied during the breeding season of 1990. Percent willow cover (shrub and mat forms), bud densities and densities of live unbrowsed terminal leaders (shrub forms) were measured as available willow-food resources for ptarmigan among sites. Patch perimeter and diameter, height, densities of live browsed and/or dead terminal leaders, and lengths of terminal leaders of shrub willows were measured as indicators of browsing by ungulates among sites. Frequencies of ungulate feces were measured as indicators of ungulate presence among sites. Willow characteristics and ungulate feces were measured in both 1989 and 1990. Ungulate feces were significantly (f <0.01) more frequent at the two southeast (SE) sites on Trail Ridge than they were at.the two northwest �224 (NV) sites. Overall avian species richness and densities were greater at SE sites, primarily due to inherent site differences. However, .. ptarmigan densities, including pairs and unpaired males, were lowest at SE sites, and declines in ptarmigan densities since 1966 were significant (l <0.01). In 100 x 50 m sampling plots and on 10-m transects, willow characteristics indicative of food-resources available to ptarmigan tended to be greater at NV sites, although not significantly (l >0.05). On lO-m transects, however, willow cover was significantly greater (l <0.05) at locations used by ptarmigan hens than it was at random locations within the territories of the hen's mates. All but two willow characteristics indicative of browsing by ungulates were similar among sites (l >0.05). Lengths of live unbrowsed terminal leaders were significantly greater (l >0.05) at SE sites (where ungulate presence had been greater), perhaps in response to browsing. Also, willow-patch diameters (on transects) were greater (l <0.05) at SE sites; patch diameters were smaller (l <0.05) at locations used by ptarmigan hens than they were in random locations within the territories of the hen's mates; and patch diameters at locations used by hens more closely matched patch diameters found at NV sites. Time budgeted to feeding by, and bite rates of, ptarmigan hens were not different among regions of Trail Ridge. However, bite rates on shrub willow were significantly lower (l <0.01) than bite rates on other foods, including mat willow. Reproductive success was poor for all hens, which precluded detection of site-related differences in reproductive success. �225 THESIS AVIFAUNA RESPONSES TO INTENSIVE BROWSING BY ELK IN ROCKY MOUNTAIN NATIONAL PARK Submitted by Cynthia Porter Melcher Department of Biology In partial fulfillment of the requirements for the Degree of Master of Science Colorado State University Fort Collins, Colorado Spring 1992 �226 COLORADO STATE UNIVERSITY April 6. 1992 VE HEREBY RECOMMEND SUPERVISION INTENSIVE ACCEPTED THAT THE THESIS PREPARED UNDER OUR BY CYNTHIA P. MELCHER ENTITLED AVIFAUNA BROWSING BY ELK.IN ROCKY MOUNTAIN NATIONAL AS FULFILLING IN PART REQUIREMENTS RESPONSES TO PARK BE FOR THE DEGREE OF MASTER OF SCIENCE. .. Committee on Graduate Work Adviser ./"' I'~ Department Head �227 ABSTRACT OF THESIS AVIFAUNA RESPONSES TO INTENSIVE BROWSING BY ELK IN ROCKY MOUNTAIN NATIONAL PARK Researchers from the Colorado Division of Wildlife monitored densities of white-tailed ptarmigan (Lagopus leucurus) on Trail Ridge in Rocky Mountain National Park (RMNP) from 1966-1988. A decline in the population was detected in the late 1970s when a population increase had been expected. The decline was deep and prolonged, with no sign of recovery by spring 1989. Willow (Salix spp.), an essential " food resource for ptarmigan, appeared damaged and decadent in areas where breeding densities of ptarmigan had declined most. Researchers with the Colorado Division of Wildlife hypothesized that breeding densities of ptarmigan had declined in response to habitat (willow) degradation caused by elk (Cervus elaphus) in alpinefkrummholz habitat. Densities of elk in RMNP had been controlled artificially until 1968 when the National Park Service discontinued control programs; the elk population subsequently increased significantly. Fragmentation and loss of elk habitat, extirpation of predators, and heavy hunting pressure immediately outside RMNP's boundaries may have encouraged elk to remain within the Park and increase their use of some habitat types, including alpine/krummholz. �228 The objectives of this study were to evaluate relationships between avian abundance/species richness, presence of ungulates, characteristics of willow, and activity budgets/reproductive success of ptarmigan hens in alpine/krummholz habitats of Rocky Mountain National Park. All bird species were censused at 4 17-22 ha sites using spot-mapping techniques from 27 Hay to 10 July 1989, and from June 7 to 1 August 1990. Activity budgets, foraging rates, and reproductive success of 12 radio-marked hens (three at each site) were studied during the breeding season of 1990. Percent willow cover (shrub and mat forms), bud densities and densities of live unbrowsed terminal leaders (shrub forms) were measured as available willow-food resources for ptarmigan among sites. Patch perimeter and diameter, height, densities of live browsed and/or dead terminal leaders, and lengths of terminal leaders of shrub willows were measured as indicators of browsing by ungulates among sites. Frequencies of ungulate feces were measured as indicators of ungulate presence among sites. Willow characteristics and ungulate feces were measured in both 1989 and 1990. Ungulate feces were significantly (f <0.01) more frequent at the two southeast (SE) sites on Trail Ridge than they were at the two northwest (NV) sites. Overall avian species richness and densities were greater at SE sites, primarily due to inherent site differences. However, ptarmigan densities, including pairs and unpaired males, were lowest at SE sites, and declines in ptarmigan densities since 1966 were significant (f <0.01). In 100 x 50 m sampling plots and on 10-m transects, willow characteristics indicative of food-resources available to ptarmigan tended to be greater at NV sites, although not sigrtificantly (f .. �22~ >0.05). On 10-m transects, however, willow cover was significantly greater (f <0.05) at locations used by ptarmigan hens than it was at random locations within the territories of the hen's mates. All but two willow characteristics indicative of browsing by ungulates were similar among sites (f >0.05). Lengths of live unbrowsed terminal leaders were significantly greater (f >0.05) at SE sites (where ungulate presence had been greater), perhaps in response to browsing. Also, willow-patch diameters (on transects) were greater (f <0.05) at SE sites; patch diameters were smaller (f <0.05) at locations used by ptarmigan hens than they were in random locations within the territories of the hen's mates; and patch diameters at locations used by hens more closely matched patch diameters found at NV sites. Time budgeted to feeding by, and bite rates of, ptarmigan hens were not different among regions of Trail Ridge. However, bite rates on shrub willow were significantly lower (f <0.01) than bite rates on other foods, including mat willow. Reproductive success was poor for all hens, which precluded detection of site-related differences in reproductive success. Cynthia P. Melcher Department of Biology Colorado State University Fort Collins, CO 80523 Spring 1992 '. �230 TABLE OF CONTENTS TITLE PAGE.................................................... Page i SIGNATURE PAGE................................................ ii ABSTRACT. ..................................................... iii TABLE OF CONTENTS............................................. LIST OF FIGURES vi viii LIST OF TABLES................................................ ACKNOWLEDGEMENTS. ............................................. CHAPTER 1. ix x EXTENSIVE USE OF ALPINE/KRUHMHOLZ HABITATS BY WILD UNGULATES: CONSEQUENCES FOR WHITE-TAILED PTARMIGAN? Introduction . Ptarmigan-Elk-Willow Relationships . Hypotheses . Study Sites and Hethods . Plots and Transects: Selection and Sampling . Occurrence of Ungulate Feces . Willow Characteristics Indicative of Available Food Resources . Willow Characteristics Indicative of Browsing by Ungulates . White-tailed Ptarmigan: Sampling . Plots and Transects: Data Transformation and Analysis Occurrence of Ungulate Feces . Willow Characteristics . Ptarmigan Densities: Data Transformation and Analysis . Results Frequencies of Ungulates Feces . Willow Characteristics Indicative of Available Food Resources . Willow Characteristics Indicative of Browsing by Ungulates . White-tailed Ptarmigan Densities Among Sites . Discussion . Literature Cited ; / . .. 1 2 4 4 8 12 13 13 15 15 16 17 18 21 23 26 26 36 �231 CHAPTER2. AVIANSPECIES RICHNESSANDABUNDANCE IN ALPINEjKRUMMHOLZ HABITATSUSED EXTENSIVELYBY llILD UNGULATES IN COLORADO Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Study Sites....................................... Methods........................................... Results........................................... Discussion. . . . . . . . . . . . . . . . . . . • . . • • . . . . . . . . . . . . . . .. Literature Cited.................................. CHAPTER3. 42 44 45 47 53 59 PRE-NESTINGACTIVITY BUDGETSANDREPRODUCTIVE SUCCESSOF FEMALEWHITE-TAILEDPTARMIGAN USING HEAVILYBROllSEDALPINEjKRUMMHOLZ HABITATS Introduction. . . . . . . . . . . . . .•. . . . . . . . . . . . . . . . . . . . . . . Hypotheses. . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . Study Sites...... ................................. Methods Selection of Hens.. . . • . • • • • • • • • • • • . • . . . . . • . • • • . . Pre-Nesting Activity Budgets of Hens .••.••..•••. Data Analysis. . . . . . . . . . • • . . . • • . • . . . . . . . . . • . . . • . . Results and Discussion Activity Budgets........................... . • . .. Bite Rates...................................... Measures of Fitness............................. Literature Cited.................................. 63 65 66 68 69 71 72 74 76 83 .. �232 LIST OF FIGURES Figure 1-1 1-2 1-3 1-4 1-5 2-1 Locations of study sites and plots on Trail Ridge in Rocky Mountain National Park, 1989 and 1990 7 Schematic representation of sampling protocol and sample hierarchies used in plots and on transects in Rocky Mountain National Park, 1989 and 1990 10 Observed and average frequencies of ungulate feces in sample plots at four sites in alpinejkrummholz habitats, Rocky Mountain National Park, 1989 and 1990 19 Observed and average frequencies of ungulate feces on transects at four sites in alpinejkrummholz habitats, Rocky Mountain National Park, 1990 20 Densities of white-tailed ptarmigan at four sites in alpinejkrummholz habitats, Rocky Mountain National Park, 1989 and 1990............................................. 27 Avian species richness and average pairs/20 ha at four sites in a1pinejkrummholz habitats, Rocky Mountain National Park, 1989 and 1990 "...•.......................... 48 �233 LIST 1-1 1-2 OF TABLES ANOVA results testing for site (or region) effects on willow characterisitics important to white-tailed ptarmigan as food at four sites in Rocky Mountain Park, 1989 and 1990 22 ANOVA results testing for site (or region) effects on willow characterisitics indicative of browsing by wild ungulates at four sites in Rocky Mountain Park, 1989 and 1990 24 2-1 Average densities of avian species breeding or regularly foraging at four sites in alpinejkrummholz habitats in Rocky Mountain National Park, 1989 and 1990 .. 49 2-2 All avian species observed using four sites in alpine/ krummholz habitats in Rocky Mountain National Park, 1989 and 1990 '. 51 3-1 Summary of activity budgets of pre-nesting white-tailed ptarmigan hens in Rocky Mountain National Park, 1990 ..... 73 3-2 Summary of age, weight, and reproductive success of white-tailed ptarmigan hens in Rocky Mountain National Park, 1990............................................... 77 �234 ACKNOVLKDGEHERTS The financial support, equipment, and field housing for this study was provided by the Colorado Division of Wildlife. Funding sources included the Colorado non-game and endangered species program, Welder Wildlife Foundation, and Federal Aid Restoration Project W-l52-R. My graduate committee went through considerable evolution over time, and I am grateful to every member, past and present, for their respective contributions to this project. Dr. Beatrice Van Horne, Department of Biology, Colorado State University, served as my adviser and gave consistent advice, support, and encouragement; Dr. Thomas Remington, Colorado Division of Wildlife, gave my thesis and manuscripts very thorough review and patiently listened to my counter arguments on every point he made; Dr. David Steingraeber, Department of Biology, Colorado State University, gave many helpful suggestions concerning willow-sampling and some "Good Work" kudos when I needed them most; Dr. Myron Baker, Department of Biology, Colorado State University, challenged me with lively discussions and shared his ideas concerning approaches to this project; Dr. Clait Braun, Colorado Division of Wildlife, initiated this project and secured the funding and resources. Dr. Braun also provided me with opportunities to give presentations, both professional and popular, for which I am grateful. .. �235 I wish to acknowledge the generous cooperation, assistance, and support provided by the staff of Rocky Mountain National Park, National Park Service. In particular, David Stevens, biologist, ensured my procurement of necessary passes and keys to operate within the Park. My field work could not have been completed without the help of Sue Swift and Craig Poley. her companionship was a joy. Sue was an excellent field assistant, and Craig helped with several heavy tasks. I am very grateful to both of them. Many researchers and support personnel at the Colorado Division of Wildlife were very generous with their time and assistance. Kenneth Giesen, who "got" me my "life" ptarmigan, Richard Hoffman, and Dr. Thomas Remington willingly brainstormed with me and provided many exciting research ideas; Diane Hall helped me deal with computer crashes, solved paperwork puzzles, and supported me through several other traumas; Dr. N. Thompson Hobbs tolerated and answered endless questions concerning SAS and data analysis. Numerous other personnel with the Colorado Division of Wildlife also provided assistance or advice. My sincerest thanks go to everyone. At Colorado State University, advice was given generously by numerous faculty and graduate students, including Dr. William Alldredge, Dr. Phillip Lehner, Dr. Ronald Ryder, and Dr. Orrin Myers. Most invaluable was the patience of Dr. David Bowden, who saw me through the statistical analyses. Most of all, I give my love and very special thanks to Ken Giesen, Jean Melcher, Pete Melcher, Maggi Melcher, and Jean Boylan. Without their unfailing love, support, and belief in me, I could not have completed my graduate career. ~ �236 CHAPTER 1 USE OF ALPINE/KRUMMHOLZ HABITATS BY WILD UNGULATES: CONSEQUENCES FOR WHITE-TAILED PTARMIGAN? EXTENSIVE INTRODUCTION White-tailed use habitat sub-alpine in alpine drainage or co-dominated brachycarpa spring Nutt.; basins. almost communities, and drainage in Colorado and alpine basins Pursh, and dominated S. 1976) are used from fall through 1975, Braun et al. 1976, Schmidt on willow Willows Ptarmigan S. brachycarpa, prior early 1988) when buds and terminal in alpine(krummholz of breeding 1988). and catkins altipetens) (Salix planifolia exclusively components (S. planifolia, leaves, Krummholz 1972). et a1. 1980, Schmidt tips, krummholz after Weber (May and Braun willow tundra, and Braun forage also essential (Lagopus leucurus by shrub willows (Hoffman the birds tips ptarmigan territories habitats are (Braun 1969, Giesen hens forage S. nivalis leader extensively Hook.) to and during nesting on buds, leader (May and Braun 1972, May 1975). Elk (Cervus elaphus canadensis) Colorado by the late l800s transplants Colorado. received RMNP initiated residents (Swift 1940). extirpated from through a series However, in 1913, elk were successfully The Estes ParkfRocky 49 elk from northwest in 1915. were nearly The population Mountain Wyoming National just prior grew rapidly, and RMNP staff were complaining reintroduced Park of to (RMNP) area to establishment of and by 1941 local that browsing elk had caused �L~/ significant damage to vegetation (Ratcliff 1941, Packard 1947). As a result, prescribed numbers of RMNP elk were periodically shot or removed until 1968 when the National Park Service (NPS) adopted a new resource-management policy that discontinued manipulative approaches to wildlife management (Natl. Park Servo 1975, 1988). Subsequent surveys indicated exponential growth of RMNP's elk population: the estimated population grew from 1,000 in 1968 to over 3,000 by the late 1980s (Braun et al. 1991), and winter-use of alpine/krummholz regions increased from 29 elk in 1933 to over 300 in 1976 (Stevens 1980b; et al. 1989). Bear Hobbs et al. (1982) estimated that carrying capacity for elk in RMNP was between 1,000-1,700, well below densities observed by the mid 1980s. Ptarmigan-Elk-Willow Relationships Historical accounts (pre-1900s) indicated that elk in Colorado used alpine regions infrequently or intermittently (Swift 1940, Packard 1947, Murie 1951, Thomas and Toweil1 1982). However, accounts of habitat-use by ptarmigan (Braun 1969, Schmidt 1969, Braun and Rogers 1971, Braun et al. 1976, Giesen et al. 1980) and recent accounts of habitat-use by elk in RMNP (Nat1. Park Servo 1975, Stevens 1980b, Green 1982, Bear 1989) indicate that significant overlap of habitat-use by ptarmigan and elk may be occurring. As elk habitat was lost to development and became more fragmented, and as hunting pressure outside Park boundaries increased, elk may have been encouraged to concentrate in the Park, especially in areas where they could find preferred foods. Generally, willows do not comprise significant portions of elk diets, although elk commonly feed on willows in RMNP during all seasons (Kufeld 1973, Hobbs 1979, Hobbs et �238 al. 1981, Baker and Hobbs 1982), and at least two studies (Olmsted 1979, Stevens 1980b) implicated heavy browsing by elk in the decline of several Salicaceae species (S. planifolia, tremuloides S. brachycarpa, Populus Michx.) in RMNP. Structures of avian communities have been altered when habitats were subjected to intensive use by ungulates (Zwickel 1972, Butler 1979, Watson and O'Hare 1979, Ryder 1980, Taylor 1986, Myrberget 1987, Tucker 1987, Knopf et al. 1988, Jackson 1991). may have occurred in RMNP. A similar phenomenon Willard and Marr (1970) showed that heavy trampling by people caused severe damage to alpine vegetation in RMNP, the recovery of which has been exceptionally slow due to severe climatic constraints. While alpine vegetation has evolved to withstand severe climate (Billings 1979), it isn't likely to tolerate processes with which it did not evolve, including intensive and prolonged trampling or browsing by ungulates. Competition for food at high densities may have pressured elk within a1pine/krummho1z areas to incorporate more willow into their diets. As a result, willow-food resources may have declined, causing the decline in breeding densities of ptarmigan. Ptarmigan using areas near Trail Ridge Road (TRR) in RMNP have been censused and banded since 1966 (Braun and Giesen 1990). Prior to the late 1970s, population dynamics of TRR ptarmigan were characterized by 7 to 10-year cycles (Braun et al. 1991). However, during the late 1970s, when a population increase was expected, densities of ptarmigan at the southeast end of Trail Ridge began declining, and eventually fell well below historically-low densities. Braun et a1. (1991) suggested that the deep and prolonged decline .. �indicated that factors besides population were influencing dynamics. This study was designed presence (frequency potentially feces), to ptarmigan, of use by browsing of ungulates densities to quantify of ungulate important indicative presence cyclic fluctuations and ungulates. Hypotheses of ungulate 2) willow characteristics 3) willow characteristics My objective and characteristics of ptarmigan. 1) an indicator of willow was to relate to breeding tested were: Ho There are no differences (P >0.05) in frequencies of ungulate feces between areas where ptarmigan had and had not declined. Ho: Willow characteristics do not differ (P >0.05) between areas with high versus low frequencies of ungulate feces. I predicted that 1) current ptarmigan lower where frequencies cover and densities unbrowsed terminal of ungulate of willow-foods breeding densities feces were higher, used by ptarmigan of ungulate feces, and frequencies of ungulate feces would be characterized variations 2) willow (buds, live leaders) would be lower in areas with high frequencies of live browsed would be and/or dead terminal in willow-patch 3) willows leaders, perimeters in areas with high by high densities low shrub heights, or diameters, wide and short terminal leaders. STUDY SITES AND METHODS Two study sites were selected TRR [Sundance breeding Basin ptarmigan the northwest in the southeast (SB) and Tombstone had declined, Ridge (SE) region of (TR)] , where densities and two study areas were selected (NW) region of TRR [Medicine Bow Curve (MBC) and Gore of in �240 Turnout (GT)], where densities of breeding ptarmigan had not declined (Fig. 1-1). including Two additional criteria were used for site selection, 1) presence of alpine/ krummholz communities, including willows, and 2) minimal visibility from TRR (requested by NPS). Site boundaries were determined by using notable landmarks, compass bearings, and counted paces. Sites were plotted on U.S. Geological Survey topographic maps (scale 1:24000), and site areas were determined using a planimeter. Sites were the areal bases for comparisons of local ptarmigan densities. Approximate site areas were: MBC - 22 ha, GT - 17 ha, SB - 20 ha, TR - 19 ha. Marr (1967) described alpine communities and climates typical of Colorado's Front Range (data collected from four sites in Niwot Ridge area, approximately 32 km south of TRR study sites). typical throughout all TRR study sites were: Community types Trifolium cushion fellfield; Dryas octopetala hookeriana Juz. and/or Dryas-Salix (S. nivalis Hook.) turf; alpine meadow comprised of Kobresia, Carex, Trifolium, Poa, and/or Acomastylis rossii R. Br. (formerly Geum rossii R. Br.); snow accumulation areas comprised of Artemisia, Carex, Poa, and/or Acomastylis; and patches of krummholz comprised of Salix spp. (S. planifolia Pursh, S. brachycarpa Nutt.), Picea engelmanii Parry, and/or Abies lasiocarpa Hook. Communities more typical of dry windswept areas (Dryas and Kobresia turf) dominated NY sites, and communities more typical of moist snow-accumulation areas (Carex and Artemisia) dominated SE sites. Community types were described in detail and mapped by Braun (1969). �Fig. 1-1. Locations of four study areas on Trail Ridge in Rocky Mountain National Park, 1989-90. Northwest (NW) region sites: Medicine Bow Curve (MBC) and Gore Turnout (GT). Southeast (SE) region sites: Sundance Basin (SB) and Tombstone Ridge (TR). Sites are outlined, and were areal bases for censusing white-tailed ptarmigan. Relative locations of 100 x 50 m plots used for sampling frequencies of ungulate feces and willow characteristics are indicated with small solid rectangles. For each site, plot 1 is the most northern plot, plot 2 is the most southern. N ~ .. t-' �I',,) .l:"I',,) ROCKY MOUNTAIN NATIONAL PARK ·":~::::::::::::::1:::::::::. DENVER COLORADO MBC 3505·3658 m ~ W TRAIL RIDGE ALPINE VISITOR CENTER »: N w o > o ...J SUNDANCE MOUNTAIN ~ Z W RAINBOW CURVE RCS z i= z I o o MILES o o 1 1 2 3 2 3 FOREST CANYON '3385.3566 4 KILOMETERS SCALE • APPROXIMATELY 1:73500 .. TSR 0 m~ - =<:» ~ TO ESTES PARK �243 Slopes at each site ranged from near 0° to approximately NW sites were steepest, intermittently. level benches narrow benches SE sites were dominated by relatively and saddles, with steep areas occurring SB was the wettest driest. with relatively Aspect 45°. occurring wide nearlyintermittently. site, TR and MBC were intermediate, and GT was the W at GT, NE to SE at ranged from NE to NW at MBC, N to SB, and NE to S at TR. Plots and Transects: Selection and Sampling In May 1989, two permanent established ungulate 100 x 50 m (rectangular) at each site (Fig. 1-1) for sampling feces and characteristics each plot was chosen subjectively representative bearing willow. of willows. plots were frequencies A starting to ensure presence for compass the first 100-m plot side; subsequent plot sides were laid out in a clockwise marked with permanent point of locally- From the starting point, a random was used to delineate of pattern. 75-cm metal rebar stakes. Plot boundaries were Plots were overlaid with a l-m line grid (Canfield 1941) (Fig. 1-2); 30 line-intercept coordinates were selected plot, ensuring 50 m plot. plots from each 50 x 50 m half of each a fairly even distribution Line-intercepts (Fig. 1-2). plot) were established placement 3 August over each 100 x of l-m2 sample- centers were marked with permanent Thus, 120 l-m2 sample-plots of quadrats, 75- (60 per 100 x 50 m per study site, for a total of 480. edges of sample-plots so that they parallel led plot edges. May through of samples were used as the centers Sample-plot cm metal rebar stakes. standardize randomly To were oriented Sampling was conducted from 27 1989 and from 6 July through 22 July 1990. �I'V ~ ~ Fig. 1-2. Two 100 x 50 m rectangular plots were established within or adjacent to each of 4 sites to sample locally-representative examples of willow. A line-intercept grid overlay (Canfield 1941) was used to define 1-m line intercepts in each plot. Thirty line-intercepts were chosen randomly from each 50 x 50 m half of the plots, ensuring relatively even spacing of samples across plots, and were used to determine the centers of 1-m2 sample-plots. Line transects (10-m) were centered on locations (visual) of radio-marked hens (HL transects) observed during a concurrent study. A random compass bearing was taken from each hen location, and followed for 100 m, where the center of another 10-m transect (RL transect) was established. Sampled areas were delineated during sampling with quadrat frames. To standardize placement of quadrats, quadrat edges paralleled plot edges and quadrat center lines were placed on transect lines. " .' �PLOTS TRANSECTS 30 line-intercepts selected randomly from 1 x 1 m grid overlay hen location tsQ) / CJ) s:: ~ +-' E I 0 50x50 m half-plot ~ E 0 LO ~ 100 along random compass bearing I HL i m ,,' transect 1 tsQ) m 2 sample-plot CJ) c quadrats ~ +-' ~o.25m2 E o I ~O.~~·~2 T"" ........... quadrats Itt o::lm~2 (not drawn to scale) RL transect N .j:'- \J1 ~ �246 In 1990, an additional the frequencies sampling of ungulate occurring at specific nesting. Between feces and characteristics places selected 3, this volume). season). The total number period, divided by 4 to determine 1st relocation was selected, sequences on the 36 locations season), between to another location used and distances additional and known season was relocations - HL transects) locations and walking (i.e., the moved by ptarmigan (Fig. 1-2). (Fig. 1-2). their mates' .. To territories, (random locations a 2nd - RL were determined by selecting 100 m along that compass bearing areas hens during the breeding yielding Two hens without radios to be paired with males holding territories season; were centered - RL transects), to sites) were also located several per selected by hens and random 1969): 10-m line transects (random locations transects per were centered (100 m was chosen on the basis of typical see Braun 1969 and Schmidt those locations were chosen systematically. Ten-m line transects of these transects compass bearing locations to yield a sample of 4 relocations was established Locations from 21 May on the number of relocations they could have used within set of 10-m transects a random repeatedly (see then every other 2nd, 3rd, or 4th (hen locations differences transects). facet of this study of selected depending hen (a total of 36 relocations). locations hens from each study by hen, during pre-nesting was always selected, hen during pre-nesting evaluate hens prior to The place of every relocation relocations of relocations, to assess of willow To obtain a sample of these hen-selected across the pre-nesting relocation for another Hens were relocated and 26 June 1990 (pre-nesting was recorded. by ptarmigan 23 and 29 May 1990, 3 ptarmigan site (12 hens) were radio-marked Chapter scheme was initiated on 36 (both banded in or adjacent times during the pre-nesting �247 season. Four transects (2 HL, 2 RL) for each of these hens were established in the same manner. To minimize observer Thus, 80 transects bias, all transects were established. were oriented north Each 10-m transect was defined with a meter tape during standardize placed placement on transect August, of quadrats, lines. sampling. center lines of quadrats Sampling was conducted to south. were 23 July to 10 1990. Occurrence of Ungulate Feces Elk fecal material is generally easy to identify, although and age class cause form, shape, and size of fecal material precluding positive sympatrically observed using identifications measured identification (Neff 1968). and Rocky Mountain bighorn where ungulate Mule deer (Odocoileus sheep (Ovis canadensis the sites on several occasions, questionable occurrences regard for species in some instances. of ungulate of origin. the 480 sample-plots fecal material Occurrences and within species occur hemionus hemionus) 'canadensis) were rendering fecal Therefore, were recorded of ungulate .. all without feces within the first and every other l-m2 along (five l-m2 samples per transect) were scored as present or absent (0). This method was used instead of pellet-group (Bennett et al. 1940) because breakup of pellet-groups. immediately diet to vary, transects plots To several alpine factors after inspection. counts contribute In 1989, feces were removed (1) to from samp~e· �248 Willow Characteristics Indicative In sample-plots, Nutt., S. planifolia was estimated intercepted measured percent On transects, a meter tape placed densities (S. brachycarpa (S. nivalis where willow on transect Hook.) (shrub or mat) lines, percent cover was live unbrowsed in a 0.01 m2 sub-sample. were estimated by mUltiplying terminal leaders the number and/or dead) by the average buds per leader type, and adding the products. If willow plot, but not in the lower right corner, (clockwise) transect, were examined (where willow Willow occurred, Characteristics With a cm ruler, live browsed Indicative lengths node when lengths samples, and the nearest adjoining in sample-plots, and/or dead terminal leaders were counted as described above). of in the samp1ecorners For each at 0.5 m intervals edges). (live unbrowsed; as the distance An average number by Ungulates leaders (in 0.01 m2 sub-samples, were measured Live browsed live browsed of Browsing of terminal leaders were missing). each type of leader Leader consecutive 5-cm from willow and/or dead) were measured tip of the woody portion occurred in a 0.01 m2 sub-sample beginning type The lower right 0.01 m2 until willow was encountered. buds were counted Bud of each leader vs. live browsed of the quadrat was used. and buds Leaders were counted. (live unbrowsed corner per 1-m2 transect. For each sample-plot, were measured Food Resources cover of shrub willow Pursh) and mat willow visually. as m/10-m of Available between leader the (or leader length was calculated as described above). only. leaders were counted on transects) (only (in 0.01 m2 sub- for .. �Height of shrub willow was measured-by placing a meter stick vertically into the shrub: height was measured as distance from substrate to tip of highest woody portion that was closest to the meter stick. For plots, 2-8 measurements were made per l-m2 sample- plot (2 measurements were made in corners of each 0.25 m2 quadrat section occupied by shrub willow) and then averaged. Average heights were weighted by percent cover of shrub willow in each sample-plot to minimize biases possibly caused by differences in percent of willow cover. For transects, heights of shrub willow were measured at 0.25 m intervals where willow intercepted the meter tape (beginning 5 cm and ending at least 5 cm from willow edges) and then averaged for each transect. A willow patch was defined by canopy separations of ~ 0.1 m (if canopies arose from different basal stems). Patch perimeter was estimated for plots (1990, only), and patch diameter was measured for transects. The perimeter (m) of any shrub-willow patch that fell completely or partially within a l-m2 sample-plot was approximated with a meter stick, and if more than 1 willow patch fell in the quadrat an average of patch perimeters was used. On transects, intercept (m) of shrub willow was measured for each patch and an average diameter per transect was calculated. It appeared that close association with conifers (Picea engelmanii Parry or Abies lasiocarpa Hook.) had major effects on willow morphology. To control for conifer effects, occurrence of conifer was recorded during sampling. -Sampled willows growing within or leeward (within I m) of conifers were scored as "1", those not growing within or leeward to conifers were scored as "0". �250 White-tailed Ptarmi~an: Samplin~ Ptarmigan were censused at each site throughout the breeding seasons of 1989 and 1990. Absolute counts of all ptarmigan, including pairs, single territorial males, and non-territorial males were attempted. Methods used to locate birds were: 1) methodically traversing sites while playing taped recordings of territorial male vocalizations (Braun et a1. 1973), which elicited responses from most territorial males, 2) locating ptarmigan during spot-mapping census visits (International Bird Census Committee 1970), and 3) following ptarmigan tracks in fresh snow, which allowed detection of territorial (paired or single) and non-territorial males that were unresponsive to the tape. Most birds were identified by their unique bandette color combination (Braun and Giesen 1990), minimizing the possibility of inflated counts. If birds appeared to be using an area fully encompassed by site boundaries, they were counted as 1 pair (or 1 bird if single). If, however, the birds appeared to use additional space outside the site boundaries, they were counted as 0.5 pairs (or 0.5 single birds), according to International Bird Census Committee standards. Plots and Tansects: Data Transformations and Analysis Occurrence of Ungulate Feces Frequency of occurrence of ungulate feces in sample-plots was calculated by summing the 60 presence/absence scores within each 100 x 50 m plot, by year; frequency of occurrence of ungulate feces on transects was calculated by summing the 20 (or 10 for the hens without radios) scores within each hen, by transect type (HL or RL). Plots and transects (hens) were subsequently assigned to a feces frequency .. �L51 category (FFC): an FFC of "B" (below) was assigned if the observed frequency was below average frequency (across plots or hens) and an FFC of "A" (above) was assigned if observed frequency was above average frequency. (Average frequencies were adjusted for uneven sample sizes; Le.; hens with 4 vs. 8 transects.) Frequencies of ungulate feces in plots were converted to percent values (frequency/60) for each plot (within site), by year. Frequencies of ungulate feces on transects were converted to percent values (frequency/20 or 10) for each hen (within site), by transect type. Square-roots of percent values were taken, arcsine-transformed (Snedecor and Cochran 1980), and then data sets were subjected to ANOVAs to test for differences among sites (PROC GLM, SAS 1988). Nested error terms for main effects were used to generate appropriate F-va1ues according to the scheme as follows: For PLOT data I used plot(site) for site effect, [site x year(site)] for year and for site x year effects; For TRANSECT data set I used hen(site) for site effect, [hen x transect type(site)] for transect type and for hen x transect type effects. Least square differences were used to determine whether effects were significant (P < 0.05). If site effect was significant, a contrast (NY vs. SE sites) was used to ascertain regional differences. Subsequently, appropriate FFCs were assigned to sites. Willow Characteristics Zero values resulting from no occurrence of willow in a sampleplot were treated as missing values (except for percent willow covers). Within plots, measurements of willow characteristics were averaged (percent cover was totaled) by site, year (not used for patch .. �252 perimeter), and conifer score, and were log-transformed [In(y+1) for percent cover of mat willow, 1n(y) for all other variables]. Within transects, by FFC and transect type (site was not used, due to missing data cells that would have resulted), willow measurements were averaged and log-transformed when necessary: [In(y+1) for percent willow covers and patch diameters; 1n(y) for heights]. Plot and transect data sets were subjected to ANOVAs to test for differences among sites or FFCs (PROC GLM, SAS 1988). Nested error terms for main effects were used to generate appropriate F-va1ues according to the scheme as follows: For PLOT data set I used p1ot(site) for site effect, [plot x conifer(site)] for conifer and site x conifer effects, [plot x year(site)] for year and for site x year effects; For TRANSECT data set I used hen(FFC) for FFC effect, [hen x transect type(FFC)] for transect type and for FFC x transect type effects. Least square differences were used to determine whether effects were significant (P < 0.05). of freedom were> If main effects were significant (and degrees 1), contrasts (NW vs. SE sites) were used to ascertain regional differences. Conifer was not used as a main effect in ANOVAs testing for differences in transect (hen) willow characteristics because transects had few occurrences of conifer (resulting in numerous missing data cells). Instead, willow characteristics (except percent cover) on transects were analyzed in 2 ways: 1) all measures combined, and 2) only those measures taken when conifer was absent. Ptarmigan Densities: Data Transformation and Analysis Site densities were converted to birds (pairs or single males)/20 ha site and to birds/40 ha region (within.year), and then '. �253 averaged over years. densities To ascertain of ptarmigan were statistically significant, combined, Separate I applied trends Cox-Stuart in breeding males) in RMNP tests for trends 1990, Braun et data (Braun and Giesen tests were conducted for MBC/GT observed (including pairs and territorial (Daniel 1978) to the population al. 1991). whether on data for all sites sites only, and for SB/TR sites only. A one- tailed test was used in each case. RESULTS Freguencies of Ungulate Frequencies Feces of ungulate feces were not homogenous for 1989 or 1990, or among transects In plots, average for 60 l-m2 samples was 37.5 in 1989 and 41.5 in 1990 (Fig. frequency 1-3). (hens). among plots Ungulate feces were more frequent SB and TR; observed 57 in 1990. than average in both plots at values ranged from 51 to 58 in 1989 and from 53 to Ungulate feces were less frequent than average in both plots at MBC and GT; observed values ranged from 13 to 37 in 1989 and from 18 to 38 in 1990. On transects, average samples was 25.2 (12.6 for 20 l-m2 samples) were more frequent values ranged frequent than average observed values along transects Ungulate feces at SB and TR; observed from 32 to 35 for hens with 8 transects Ungulate for 40 l-m2 (Fig. 1-4). than average along transects 20 for hens with 4 transects. transects). •frequency fecal material and from 18 to was less for all hens at MBC and GT; ranged from 14 to 25 (all MBC and GT hens had 8 An FFC value of "A" was, therefore, and an FFC of "B" was assigned to NW sites. assigned to SE sites, �254 MBC PLOT 1 MBC PLOT 2 iii 1989 [] 1990 ~ AVERAGE. ALL PLOTS GT PLOT 1 S8 PLOT 1 TR PLOT 1 . o 10 20 30 40 50 60 FREQUENCY Fig. 1-3. Observed frequencies of ungulate feces in 2 plots (60 possible per plot) at each of 4 sites in Rocky Mountain National Park, 1989-90. Average frequencies for all plots, by year, are also shown. �MBC/1 MBC/2 MBC/3 GT/4 z GT/5 w J: ..._ w e-n GT/6 I- SB/7 SB/8 .. TR/10 TA/001 I OBSERVED TA/002 ~ AVERAGE, ALL HENS o 10 20 30 40 FREQUENCY Fig. 1-4. Observed and average frequencies of ungulate feces on 8 (4 for hens 001 and 002) 10-m transects per hen (40 possible per hen; 20 possible for hens 001 and 002) at locations used by 11 pre-nesting white-tailed ptarmigan hens in Rocky Mountain National Park, 1990. �256 Site was a significant factor explaining variation in 3·, frequencies of ungulate feces (PLOTS: F ~ 27.44, P ~ 0.004, df TRANSECTS: F ~ 25.72, P 0.0004, df - 3). SE frequencies were significantly higher than NW frequencies (PLOTS: F - 78.02, P 0.0009, df - 1; TRANSECTS: F - 68.33, P 0.0001, df - 1). Although a year effect was not evident (P > 0.05), 6 of 8 plots had higher frequencies of ungulate feces in 1990 than in 1989, which may be biologically significant (see discussion). Willow Characteristics Indicative of Available Food Resources ANOVA results regarding analyses of all willow characteristics indicative of food resources are summarized in Table 1-1. In plots, neither shrub nor mat willow covers were different among sites, although year (F - 33.59, P - 0.0044, df - 1) and site x year (F 21.75, P 0.0061, df - 3) effects were significant for shrub willow (SE vs. NW contrast was not significant). On transects, percent cover of shrub and mat willow were greater at NW sites than at SE sites, but not significantly (P - 0.2091 and P - 0.2811, respectively). However, more shrub willow occurred on HL transects than on RL transects (F 7.22, P - 0.0312, df - 1). In plots, densities of live unbrowsed terminal leaders were greater at NW sites, although significance was not detected (P 0.2463). Densities were greater when associated with conifer (F 21.69, P - 0.0096, df - 1). There was also a significant site x conifer interaction (F ~ 22.42, P - 0.0058, df - 3): densities of live unbrowsed terminal leaders were greater at SE sites when associated with conifer and greater at NW sites when not associated with conifer (F - 47.15, P ~ 0.0024, df - 1). On transects, no main effects �L:JI Table 1-1. ANOVA results testing for site or FFC [above (A) versus below (B) average frequency of ungulate feces] effects on willow characteristics indicative important as food resources (percent shrub willow or mat willow cover, densities of live unbrowsed terminal leaders, bud densities) to white-tailed ptarmigan on Trail Ridge in Rocky Mountain National Park, 1989 and 1990. Medicine Bow Curve (MBC) and Gore Turnout (GT) were northwest (NY) sites (FFC-B), and Sundance Basin (SB) and Tombstone Ridge (TR) were southeast (SE) sites (FFC-A). VARIABLE Shrub Cover Mat Cover Live Unbrowsed Terminal Leaders Buds SOURCE df F P T Site Site Typeb 3 3 1 1.78 1.96 7.22 NS NS 0.031 P Site 3 4.78 0.083 T Site 3 1.56 NS P Site Conifer 3 1 2.07 21.69 NS 0.010 Site x Conifer 3 22.42 Contrast 0.006 0.002 pa T FFC FFC x Type 1 1 0.06 7.92 NS 0.048 P Site Site x Conifer 3 2.17 3 7.12 Contrast NS 0.044 0.026 FFC Type 1 1 0.30 0.01 NS NS FFC x Type 1 0.29 NS T LS MEANS higher at NY HL-O.ll RL-0.05 GT-O.OO MBC-5.17 SB-0.69 TR-1.36 higher at NY higher NY 0-1.56 1 -1.82 NYx 0-1.97 NYx 1-1.85 SE x 0-1.17 SE x 1-1.80 higher at B B x HL-3.12 B x RL-2.83 A x HL-2.30 A x RL-3.46 higher at NY NYx NYx SE x SE x 0-3.44 1-3.27 0-3.11 1-3.40 HLRLB x B x A x A x 25.67 49.00 HL-36.74 RL-32.25 HL-17.28 RL-61.84 P _ plots, T - transects bType - transect type [Hen location (HL) versus Random location (RL)] cPresence of Conifer - 1, Absence of Conifer - 0 a .' . �258 influenced measures densities of live unbrowsed combined. conifer However, (because missing significant - 0.0481, data cells would have resulted, in which case effects measurements FFC x transect densities In plots, bud densities SE sites, although an interaction densities densities occurring 0.0255). At SE sites, bud densities conifer, at NW sites bud densities present. Effects On transects, of transect transect influenced measurements a 7.92, P (F at at NW sites. at NW sites than at However, there was df - 3), with with conifer with conifer and (F - 12.06, P - in the presence of were higher when conifer was not were not different type (F - 8.90, P 0.0406, (F - 10.48, but the effects could on RL transects on HL transects were higher bud densities type interactions significant, occurring at SE sites when associated at NW sites when not associated by of conifer had to (F - 7.12, P - 0.0441, greater conifer was detected was not detected. of site x conifer influenced by conifer), tended to be greater significance being greater influenced type interaction df - 1), with greater SE sites and greater leaders with all after removing measurements not be used as a main effect, be removed by deleting terminal df - 1) and FFC x P - 0.0318, df - 1) were disappeared were removed among FFCs. completely (P - when conifer- 0.9266 and 0.6174, respectively). Willow Characteristics ANOVA indicative results sites. However, of conifer regarding of browsing plots, perimeters Indicative analyses by ungulates of shrub-willow perimeters (F ~ 10.21, of Browsing P = of all willow are summarized characteristics in Table 1-2. In patches were not different were significantly 0.0331, by Ungulates df ~ 1). greater among in the presence On transects, all main .. �Table 1-2. ANOVA results testing for site or FFC [above (A) versus below (B) average frequency of ungulate feces] effects on willow characteristics indicative of browsing by ungulates (shrub willow patch perimeter or diameter, shrub willow heights, densities of live browsed and/or dead terminal leaders, lengths of terminal leaders) on Trail Ridge in Rocky Mountain National Park, 1989 and 1990. Medicine Bow Curve (MBC) and Gore Turnout (GT) were northwest (NW) sites (FFC-L), and Sundance Basin (SB) and Tombstone Ridge (TR) were southeast (SE) sites (FFC-H). VARIABLE SOURCE df Patch Perimeter pa Site Coniferb 3 1 0.85 10.21 NS 0.033 FFC 1 9.59 0.017 Typec 1 43.73 0.003 FFC x Type 1 56.62 0.002 Site Conifer 3 1 0.27 15.73 NS 0.017 FFC FFC x Type 1 1 0.06 7.92 NS 0.048 Length Live P Unbrowsed Terminal Leaders Site 3 7.67 Contrast 0.039 0.010 Live Browsed/ Dead Terminal Leaders P Site 3 0.77 NS Live Browsed T Terminal Leaders Site 3 0.30 NS Length Live Browsed and/or Dead Terminal Leaders Site 3 3.30 NS Diameter Height T P T P F P LS MEANS 0-2.77 1-3.39 B-0.67 A-l.32 HL-0.48 RL-1.52 B x HL-0.75 B x RL-0.60 Ax HL-O.21 Ax RL-2.43 0-3.09 1-3.73 higher at B B x HL-3.12 B x RL-2.83 Ax HL-2.30 Ax RL-3.46 NW-0.87 SE-1.50 P ~ plots, T - transects Presence of Conifer - 1, Absence of Conifer - 0 cType - transect type [Hen location (HL) versus Random location (RL)] a b ~ .. �260 effects influenced patch diameters. Patch diameters were greater at SE sites (F - 9.59, P - 0.0174, df 1) and greater on RL transect types (F - 43.73, P - 0.0027, df 1); FFC x transect type interactions were significant (F 56.62, P - 0.0017, df - 1): diameters were greatest on RL transects at SE sites and greatest on HL transects at NW sites. Also, extreme high and low values occurred on RL and HL transects (respectively) at SE sites; values observed for HL and RL transects at NW sites were intermediate and similar to each other. In plots, willow heights were similar among sites. However, willow height was taller- in the presence of conifer (F - 15.73, P 0.0166, df - 1). On transects, willow heights were not different among FFCs, although they tended to be shorter at SE sites. However, an FFC x transect type interaction was detected when measurements influenced by conifer were removed (F - 7.92, P - 0.0481), with height being greater on HL transects at SE sites and greater on RL transects at .NW sites. Densities of live browsed and/or dead terminal leaders (plots) and densities of live browsed terminal leaders (transects) did not differ among sites or between FFCs. Also, effects of conifer, transect type, and interactions of main effects were not significant. In plots, lengths of live unbrowsed terminal leaders were different among sites (F - 7.67, P - 0.0391, df - 3), with lengths being greater at SE sites than at NW sites [1.50 versus 0.87 em, (In-transformed) respectively; F - 21.89, P - 0.0095, df - 1]. Lengths of live browsed and/or dead terminal leaders were not different among sites. �261 White-tailed Ptarmigan Densities Among Sites The ptarmigan census was believed to be complete. were highest at NW sites where FFC was "B". Densities What contributed to higher densities at NW sites were not only more pairs, but more single territorial and non-territorial males. The 2-year average number of pairs/20 ha for MBC and GT sites was 2.50 and 2.90, respectively, versus 1.59 and 0.79 at SB and TR sites (Fig. 1-5). Single territorial males/20 ha numbered 0.68 and 0.29 at MBC and GT sites, respectively, versus 0.00 and 0.26 at SB and TR sites. Single non- territorial males/20 ha numbered 0.23 and 0.29 at MBC and GT sites, respectively, and 0.00 at both SE sites. Ptarmigan density/40 ha during the breeding seasons (averaged over 1989 and 1990) was 12.29 at NW sites and 4.84 at SE sites. The Cox-Stuart test revealed a highly significant downward trend in ptarmigan breeding densities across all sites [P (K ~ 0 1-12, 0.50) - 0.0002] between 1966 and 1989 (1990 densities not published yet). Interestingly, downward trends were significant at MBC/GT sites (P {K ~ 1 I 12, 0.50} - 0.0031) and at SB/TR sites [P (K ~ 0 I 11, 0.50) 0.0005] (1966 through 1990) (data extrapolated from Braun et a1. 1991). DISCUSSION Frequencies of ungulate feces were unquestionably greater at SE sites where ptarmigan densities had declined most consistently (Braun et al. 1991 explained that annual variations in breeding densities of ptarmigan were lower at SE sites than they were at NW sites, indicating a more steady downward trend at SE sites). As a relative index of elk presence and habitat use among sites, feces frequency �262 3.5 II PAIRS 3 ILl NON-TERRITORIAL MALES D SINGLE TERRITORIAL MALES 2.5 co .c: 0 2 C\I ~ en z w 1.5 Cl .. 1 0.5 o MBC GT 5B TR Fig. 1-5. Densities of white-tailed ptarmigan pairs, single territorial males, and single non-territorial males at Medicine Bow Curve (MBC), Gore Turnout (GT), Sundance Basin (SB), and Tombstone Ridge (TR) in Rocky Mountain National Park, 1989 and 1990 breeding seasons. Densities were calculated from a two-year average of complete counts. �263 data were useful: either more adult elk used SE sites, or similar numbers of elk used all sites but spent more time at SE sites. Transect data confirmed that frequency results in plots were not artifacts of bias resulting from observer choice of plots. It was surprising to find no differences in frequencies of ungulate feces on HL versus RL transects. Assuming that HL transects represented areas preferred by hens on a small spatial scale (within territory), ptarmigan did not seem to avoid areas used heavily by ungulates. However, on a larger scale, (sites) it may be that ptarmigan did avoid areas (SE sites) used heavily by ungulates. Frequencies of ungulate feces also represented presence of mule deer or bighorn sheep. Size, shape, and form generally allowed positive identification of fecal material originating from elk, but there were exceptions. In general, however, ungulate feces represented presence of elk. Although a significant year effect was not detected, frequencies of ungulate feces tended to be higher in 1990 than in 1989. Freezing and desiccation, 2 prevalent conditions in Colorado alpine systems, retard decomposition rates of biotic material (Marr 1967). As a consequence, ungulate feces counted in 1989 probably represented many years of deposition. However, because feces were removed from plots in 1989, feces observed in plots during 1990 were less than 1 year old (except where older feces may have blown into sample-plots between years). Therefore, higher frequencies of ungulate feces in 1990 may be biologically significant, even if not statistically significant. Ungulates presence in the alpine may be increasing. Interestingly, higher frequencies were mostly attributable to increases at NY sites. If presence of ungulates is increasing, it may be increasing at NY �264 sites faster than at SE sites, which could be predicted if food resources at SE sites have been diminished. Feces data from transects, which represented cushion fellfields, turf, meadows, snow accumulation areas, and areas below treeline, as well as willow(krummholz, indicated that ungulates occurred in all habitat types. Neff (1968) pointed out that ungulates tend to defecate where they rest and ruminate. In other words, high frequencies of ungulate feces in willow/krummholz habitat do not necessarily indicate that ungulates foraged in that habitat. However, elk were observed using willows for foraging in alpine/krummholz habitat throughout both field seasons. Elk cows with calves often were observed foraging or resting in or near GT plots where small ungulate feces, probably originating from calves, contributed to high frequencies of ungulate feces. While feces data did not distinguish among age classes of elk, it was apparent that elk of all ages used TRR sites. Holmgren and Hutchings (1972) and Clements (1990) found that shrub production and vigor declined when shrubs were browsed during periods of vegetative growth as opposed to being browsed during periods of dormancy (Clements examined a willow spp. in a montaneriparian habitat in northern Colorado). In alpine regions of RMNP, where low moisture availability and brief growing seasons constrain net primary production, it is likely that willow vigor and production would be especially poor under heavy browsing pressure during periods of growth. occurred. forms. Fecal form (pellets vs. chips) can indicate when browsing Presence/absence data did not distinguish between fecal It was clear, however, that pellets were considerably more prevalent than chips (after accounting for total volume/defecation) .. �throughout all sites, indicating that elk used sites primarily during periods of vegetation dormancy. In addition, 6 elk antlers were found at MBC in early spring 1990, confirming that bull elk were present during winter 1989-1990. Elk chips were encountered at all sites, indicating elk used sites during periods of vegetation growth, as well. I observed adult elk frequently foraging on willow at NY sites throughout spring and summer during 1989 and 1990; to be used similarly, but to a lesser extent. SE sites appeared Because browsing x season interactions can have profoundly different effects on shrub vigor, future studies of elk/willow relationships should be designed to evaluate levels of browsing among sites during each season. If breeding densities of ptarmigan along TRR in RMNP were limited by quantities of willow-food resources, then densities should have been lowest where willow foods were lowest. Also, significantly more shrub-willow cover should have occurred in locations chosen by hens than in random locations within their territories, which was observed. While no variables indicative of available willow-food resources differed among sites, cover of mat and shrub willow (on transects), densities of live unbrowsed terminal leaders, and densities of buds all tended to be greater at NY sites where ptarmigan densities were greater. Several factors may have precluded finding statistically significant differences. First, plots were chosen specifically to include willow, and it may be that plots did not adequately represent coverage of willow (scale too small). Second, transects were chosen on the basis of hen choices, which presumably would include some willow, and it may be that there is a lower threshold of willow cover with which they associate (see discussion in Chapter 3, this volume). Again, a larger-scale approach (measuring �266 willow cover over a whole site) may have yielded significant site effects. Third, it is possible that percent willow cover had been greater at SE sites prior to increases in RMNP elk populations, but was diminished over time so that differences between SE and NW sites no longer existed. Lack of historical data precludes making inferences concerning declines in percent cover of willow, although Braun et al. (1991) did find long-term declines of willow cover on transects in various sub-alpine and alpine regions of RMNP. Effects of year and site x year interactions on willow cover in plots were probably a result of observer differences between years, only. Fourth, if differences in willow cover did exist, then largescale differences in absolute numbers of buds and live unbrowsed leaders probably existed. Densities may be relatively similar from shrub to shrub (small scale). Fifth, it may be that there were no real differences in food resources among sites. Elk may have browsed equally at all sites. Significant downward trends in breeding densities of ptarmigan were detected for both SE and NW regions, and I observed groups of elk foraging on willow at NW sites frequently. Therefore, further studies should be designed to compare willows along TRR with willows in regions of Colorado that are relatively unused by browsing ungulates. Interestingly, live unbrowsed leader densities and bud densities were greater at SE sites (in plots) when associated closely with conifers. Conifers may have provided refuge for willows by diminishing willow "apparency" to browsing elk. The fact that leader and bud densities at SE sites were greater when associated with conifer supports this possibility. The FFC x transect type .. �267 interaction indicated that appeared when effects that SE hens selected lower densities selected This could happen unavailable see Chapter Willow browsing on willow shrubs while willow patches and heights patches and height. of leaders were as indicators to foraging When pre-nesting on the substrate of willow that patch perimeters have suggested dynamics that animals choose (Kamil et al. 1987). in terms of perceived are similar, but patch size at site B is larger, causing the other hand, numerous ptarmigan ptarmigan. reach. between efficiency. and foraging could contribute to ptarmigan sites A and B would be lower at site B. small and scattered and movement foraging food abundance abundance. ratios to be smaller at site B than at site A, then food abundance more searching foraging However, or "apparent" if areas of willow cover at hypothetical "perceived" or diameters of ptarmigan. For example, perimeter:area hens (i.e., they did not enter to foraging food abundance of ptarmigan, ptarmigan they fed along the perimeters theorists food must be measured leader densities). important could also be important could be important with greater (whereas NW hens densities potentially to feed), indicating Optimal-foraging leaders that had (too tall for hens to reach from the shrubs, standing shrubs 3, this volume). such as patch dimension foraged with higher characteristics by ungulates terminal shrubs that had higher if willows to the birds substrate; areas with willow of live unbrowsed areas with willow of conifer were removed patches, The same principle possibly require reducing If patch size does affect perceived efficiency, to localized patches might declines then sub-optimal in breeding patch size densities would apply to willow of too tall to On �268 Variations may indicate ptarmigan assumed in patch size were more extreme heavy browsing foraging at those sites. to be atypical. However, willows moderately-sized willow patches possibly see Bryant 1981) or die-back because territories However, ( in response appeared diameters to heavy browsing. to be "mowed" of willow patches diameters FFC x transect pre-nesting It appears diameters, not the extreme indicated of browsing diameters transformed), were on HL of willow patches at choice by of moderate at SE sites. did not differ among sites, they may be by ungulates, although variations I suggest that real [heights on HL at NW sites were 3.12 and 2.83 cm (In- respectively, and heights on HL versus RL transects SE sites were 2.30 and 3.46 cm (In-transformed), sites, willows on transects that willow-patch observed were masked by site-specific versus RL transects finding for all HL transects. that hens prefer patches willow heights poor indicators did not differ hens may depend on local average patch dimensions. differences patch diameters type interactions ptarmigan Because (severely hedged) were smaller across all sites, and average diameters NW sites more closely matched tended to > 30 m or < 0.05 m choice may have precluded Interestingly, in many (e.g., 2-4 m diameter). In plots, willow patch perimeter at SE sites. transects of willows were (via growth of new basal shoots; occurred among sites, and again observer greater patches for in patch dimensions in ptarmigan spreading In some cases, willow patches differences. Extremes at SE sites were extreme diameter), into tiny patches. and have consequences Based on my observations alpine areas of Colorado, grow in discrete by ungulates at SE sites, which were barely respectively]. taller than cushion plants areas, but many grew quite tall in snow accumulation at At SE in exposed areas where they .. �would receive abundant moisture, and where they would be protected from browsing and weather a large part of the year. The significant FFC x transect type interaction (with effects of conifer removed) indicated that hens chose sites with shorter willows at SE sites and sites with taller willows at NY sites. There is probably a maximum willow height suitable for ptarmigan, which may have been exceeded at SE sites more than at NY sites (willows on RL transects at SE sites were considerably taller than willows on HL transects at SE and NY sites or willows on RL transects at NY sites). Of the remaining willow characteristics believed to be important indicators of browsing by ungulates, only lengths of live unbrowsed terminal leaders were different among sites. SE sites. This result was unexpected. Lengths were greater at Assuming that more browsing on willows by elk had occurred at SE sites, and assuming that willow vigor at those sites would be poor, I expected all leaders to be shorter at SE sites. Interestingly, a large portion of live unbrowsed terminal leaders at SE sites were primary (new basal shoots), while most at NY sites were secondary, tertiary, etc. Bryant (1981) found that browsing by snowshoe hares (Lepus americanus) stimulated development of adventitious basal shoots in several tree/shrub species, including willows. If more browsing at SE sites resulted in removal of most terminal leaders (and terminal buds), then significant reductions in levels of auxin hormone (normally released by terminal meristems and which supresses development of new shoots) could have allowed development of unusually long leaders from any remaining buds. There are numerous alternative hypotheses that could explain declines in ptarmigan densities. One possibility is that browsing by elk elevated levels of secondary plant compounds (phenolic glycosides �270 and other compounds) in willows. Ptarmigan may avoid willows with elevated levels of toxins or exhibit lowered fitness by feeding on more toxic willows. Numerous studies have shown that herbivores avoid plants containing high levels of toxic compounds (Freeland and Janzen 1974, Bryant and Kuropat 1980, Bryant 1981, Coley et al. 1985, Clausen et al. 1989, and Remington 1990), and Bryant (1981) found that browsing stimulated growth of adventitious shoots that were heavily defended with elevated levels of secondary compounds. When blue grouse (Dendragapus obscurus) were fed unpalatable plants (assumed to have higher toxin levels), excretions of nitrogen per gram of ingested food were higher (Remington 1990), indicating that detoxifying secondary plant compounds was metabolically expensive. If severe and chronic browsing stimulated elevated levels of secondary compounds in willows, and if those compounds required ptarmigan to use significantly more nutrients to detoxify the compounds, then decreased ptarmigan survival and/or reproductive fitness could occur as a result. The combined effect of decreased food resources and greater toxicity could have synergistic effects. Breeding densities of ptarmigan fluctuated at fairly regular intervals until about 1979, indicating that ptarmigan densities may have cycled by virtue of intrinsic mechanisms (Wynne-Edwards 1964, Chitty 1967, Moss 1971, Moss et al. 1984). If densities were low in the late 1970s'due to such a cycle, but were "slammed" down further by other factors such as severe climatic events, increases in predator populations that followed increases in elk populations, and/or diseases, then a population low could have been deeper and more prolonged. Ptarmigan densities have increased slightly during the �LIL past two years, increase. indicating Time may be all that is needed In conclusion, Rocky Mountain restricted greater are positively In addition, of Trail Ridge. correlated significant abundance are prevalent However, of willows long-term establish corroborations that warrant my recommendation On the premise in eastern I believe further to the National regarding ungulate with greatest overlap LITERATURE occurrence resources of used by have declined most, pressure most. results are necessary to that my results present strong In addition, it is that current management be reviewed very critically. (Odocoileus virginianus) densities Parks are causing ecological densities and have declined to those I have studied here, Warren that ungulate is not densities Park Service in of elk and ptarmigan investigation. populations that high ungulate National on Trail Ridge that indicate heavy browsing data and experimental cause and effect. this possibility. More consistent of willow-food at sites where ptarmigan to an and the decline tend to be lower at sites where numbers and characteristics similar densities Park are significant, feces, and indicate ptarmigan may be yielding to support in ptarmigan to just one portion habitat-use. policies declines National declines ungulate that the decrease be controlled problems, problems (1991) has recommended artificially in National Parks. CITED Baker, D. L., and N. T. Hobbs. 1982. of elk summer diets in Colorado. 46:694-703. Composition and quality J. Wildl. Manage. Bear, G. D. 1989. 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Physiological ecology of white-tailed ptarmigan in Colorado. Ph.D. Diss., Univ. Colorado, Boulder. 3llpp. _____ , and C. E. Braun. 1972. Seasonal foods of adult white-tailed ptarmigan in Colorado. J. Wildl. Manage. 36:1180-1186. Moss, R., A. Watson, and P. Rothery. 1984. Inherent changes in the body size, viability, and behavior of a fluctuating red grouse (Lagopus lsgopus scoticus) population. J. Anim. Ecol. 53:171-189. Mossop, H. D. 1971. A relation between aggressive behavior and population dynamics in blue grouse. M.S. Thesis, Univ. British Columbia, Canada. l18pp. Murie, O. J. 1951. The elk of North America. Harrisburg, PA. 376pp. Stackpole Co., Myrberget, S. 1987. The effects of sheep grazing on a willow grouse breeding habitat. Fauna 40:144-149. National Park Service. 1975. Resource management plan: Rocky Mountain National Park and Shadow Mountain National Recreation Area. U.S. Dept. Inter., Natl. Park Serv., Estes Park, CO. 88pp. 1988. Statement for management. U.S. Dep. Inter. Natl. Park Servo NPS D-23d. Washington, D.C. 60pp. Neff, D. J. 1968. The pellet-group count technique for big game trend, census, and distribution: a review. J. Wildl. Manage. 32:597-614. Olmsted, C. E. 1979. The ecology of aspen with reference to utilization by large herbivores in Rocky Mountain National Park. Pages 87-89 in M. S. Boyce, and L. D. Hayden-Wing, eds. North American elk: ecology, behavior, and management. Univ. Wyoming, Laramie. .. �L/~ Packard, F. M. 1947. A study of deer and elk herds of Rocky Mountain National Park. J. Mammal. 28:4-12. Ratcliff, H. M. 1941. Winter range conditions in Rocky Mountain National Park. Trans. No. Am. Wildl. Conf. 6:132-139. Remington, T. E. 1990. Food selection and nutritional ecology of blue grouse during winter. Ph.D. Diss., Univ. of Wisconsin, Madison. l16pp. Ryder, R. A. 1980. Effects of grazing on bird habitats. Pages 51-64 in Management of western forests and grasslands for non-game birds. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. INT-86. SAS Institute, Inc .. 1988. SAS/STATe Procedures guide: release 6.03 edition. Cary, NC. 1029pp. Schmidt, R. K., Jr. 1969. Behavior of white-tailed ptarmigan in Colorado. M.S. Thesis, Colorado State Univ., Fort Collins. l74pp. 1988. Behavior of white-tailed ptarmigan. Pages 270299 in Bergerud, A. T., and M. W. Gratson, eds. Adaptive strategies and population ecology of northern grouse. University of Minnesota Press, Minneapolis. Snedecor, G. W., and W. G. Cochran. 1980. Statistical methods, 7th ed. Iowa State University Press, Ames. 507pp. Stevens, D. R. 1980a. The deer and elk of Rocky Mountain National Park: a ten-year study. U.S. Dep. Inter., Nat1. Park Servo Rep. ROMO-N-13, Estes Park, CO. 163pp. 1980b. Effect of elk on alpine tundra in Rocky Mountain National Park. Pages 228-241 in C.L. Jackson and M.N. Schuster, eds. Proc. High Altitude Revegetation Workshop 4. Colorado State Univ. Infor. Series 42. Swift, L. W. 1940. A partial history of the elk herds of Colorado. J. Mammal. 26:114-119. Taylor, D. M. 1986. Effects of cattle grazing on passerine birds nesting in riparian habitat. J. Range Manage. 39:254-258. Thomas, J. W. and D. E. Toweill. 1982. Elk of North America: Ecology and Management. Stackpole Books, Harrisburg, PA. 698pp. Tucker, T. L. 1987. Cattle grazing affects nongame wildlife populations and fish habitat in a montane riparian area. M.S. Thesis, Colorado State Univ., Fort Collins. 84pp. �276 Warren, R. J. 1991. Ecological justification for controlling deer populations in eastern National Parks. Trans. 56th N. Am. Wildl. and Nat. Res. Conf., Wildl. Manage. Institute. Watson, A., and P. J. O'Hare. 1979. Red grouse populations on experimentally treated and untreated Irish bog. J. Appl. Ecol. 16:433-542. Weber, W. A. 1976. Rocky Mountain Flora. Univ. Press, Boulder. 479pp. Colorado Assoc. Willard, B. E., and J. W. Marr. 1970. Effects of human activities on alpine tundra ecosystems in Rocky Mountain National Park, Colorado. Biol. Conserve 2:257-265. Wynne-Edwards, V. C. 1964. Sci. Am. 211:68-75. Population control in animals. Zwickel, F. C. 1972. Some effects of grazing on blue grouse during summer. J. Wildl~ Manage. 36:631-634. �L. I I CHAPTER 2 AVIAN SPECIES RICHNESS AND ABUNDANCE IN ALPINEjKRUMMHOLZ HABITATS USED EXTENSIVELY BY WILD UNGULATES INTRODUCTION Avian diversity can be altered and/or diminished when vegetation is severely and persistently damaged by grazing/browsing ungulates (Zwickel 1972, Butler 1979, Ryder 1980, Taylor 1986, Myberget 1987, Tucker 1987, Knopf et al. 1988, Jackson 1991). Although domestic livestock have been the focus of most ungulate-grazing/avifaunaresponse studies, high densities of wild ungulates have been implicated in at least two studies. Butler (1979) found that high densities of white-tailed deer (Odocoileus virginianus) using a small wildlife preserve in an eastern U.S. deciduous forest had eliminated the forest understory and its associated guild of ground-nesting birds. Jackson (1991) found that highest levels of browsing by elk (Cervus elaphus) and moose (Alces alces) were correlated with lowest densities of passerine birds in montane willow (Salix spp.) riparian systems in Wyoming. In Rocky Mountain National Park (RMNP) , situated within Colorado's Front Range, elk populations were controlled artificially from the mid-1940s until the late 1960s. However, in 1968, the National Park Service adopted a new policy that discontinued management of wild-animal populations. Discontinued management and .. �278 several other increase factors probably of the elk population concentrate in RMNP see Chapter 1, this volume). surrounding areas from browsing Olmsted (1979) concluded impaired Damage densities (Braun and Giesen alpine/krummholz other species 1966, Pattie a period when elk (pers. comm.) observed severely damaged that breeding to declines avifaunal communities habitats; 4-5 breeding occur less frequently and Verbeek that and densities in willow of cover (see vertical richness (1970) demonstrated in part due to low moisture are common growing by elk could significantly 1965, Johnson 1988). structure in Colorado's (human foot-traffic) as the alpine and a few Severe of plant alpine tundra. that growth of alpine vegetation availability, and very brief climate-constrained species in Rocky Mountain (Bailey and Niedrach composition/limited from perturbations debris, are simple 1966, Braun 1980, Kingery limit avian species and Marr and recovery browsing 1980b) (Lagopus leucurus altipitens) had declined 1988) in response and simple communities driven (1980a, 1. this volume). Typically. Willard Stevens during in RMNP were becoming ptarmigan of aspen (Salix planifolia Pursh, S. shrubs Braun and Giesen shrubs by the late 1970s. 1976) in RMNP was seriously by elk. by the early 1980s, and suspected white-tailed climate after Weber et al. 1991; in RMNP and and regeneration in RMNP had declined increased. alpine willow to vegetation that vigor rapid of those elk to by elk was observed cover of willow brachycarpa Nutt.) Chapter and the tendency by high levels of browsing found that canopy to a subsequent (Bear 1989, Bear et al. 1989, Braun (Populous tremuloides Michx.; decadent contributed shearing seasons. tundra, severe in RMNP effects In a system is slow, of windas and persistent alter associations and .. �279 morphologies of vegetation and, consequently, the structures of avian communities. Long-term monitoring can be useful for detecting community-level changes. First, however, baseline data must be established. The objective of this study was to establish baseline data by documenting current species richness and abundance of breeding birds in alpinejkrummholz habitats in RMNP. In addition, I recorded avian behaviors and habitat use that could be relevant with respect to changes in vegetation, and discuss the possible consequences of those changes for species using alpinejkrummholz habitats. STUDY SITES Four study sites were selected near Trail Ridge Road (TRR) in RMNP for comparisons of local avian communities: Medicine Bow Curve (MBC) , Gore Turnout (GT) , Sundance Basin (SB), and Tombstone Ridge (TR). The criterium for site selection was presence of relatively similar proportions of alpinejkrummholz-habitat types. Study area boundaries were determined by using compass bearings taken from distinctive geomorphic and topographic features. Boundaries were plotted on U.S. Geological Survey maps (scale 1:24000), and site areas were determined by using a planimeter. Approximate areas were: MBC 22 ha, GT - 17 ha, SB - 20 ha, TR ~ 19 ha. Elevations ranged from 3475 to 3660 m. Climate and community associations typical of Front Range alpinejkrummholz communities were described by Marr (1967). Vegetation associations found within my study sites were mapped and described by Braun (1969). Briefly, community types (after Braun 1969) and plant species (after Weber 1976) common throughout all sites �280 were: Trifolium and/or Dryas-Salix Kobresia, cushion fellfield; Dryas octopetala (S. nivalis Carex, Trifolium, hookeriana Juz. Hook.) turf; alpine meadow comprised of Poa, and/or Acomastylis rossii R. Br. (formerly Geum rossii R. Br.); snow accumulation areas comprised of Artemisia, Carex, Poa, and/or Acomastylis; comprised of Salix spp. (S. planifolia Picea engelmanii and patches of krummholz Pursh, S. brachycarpa Parry, and/or Abies lasiocarpa Hook. Nutt.), Communities more typical of dry wind-swept areas (Dryas and Kobresia turf) dominated sites at MBC and GT, and communities more typical of moist snow-accumulation areas (Carex and Artemisia) and TR. dominated sites at SB Sites were described in greater detail in Chapter 1 (this volume). METHODS Birds were censused at each site throughout the breeding seasons of 1989 and 1990. Census methods for ptarmigan included: 1) methodically traversing sites while playing tape recordings of territorial-male vocalizations (Braun et al. 1973), which elicited responses from most territorial males, 2) locating ptarmigan during spot-mapping census visits (International Bird Census Committee 1970), and 3) following ptarmigan tracks in fresh snow, which allowed detection of unresponsive males. Most ptarmigan were identified by their unique color-bandette combinations (Braun and Giesen 1990), minimizing the possibility of inflated counts. If a ptarmigan pair appeared to be using an area fully encompassed by site boundaries, it was counted as 1 pair. If, however, the pair appeared to use additional space outside site boundaries, it was counted as 0.5 pair .. �LOL (0.5 bird for single males). Single males, territorial and non- territorial, were counted similarly. Spot-mapping procedures were used to census all other species. Deep snow early in the breeding season and only sporadic occurrence of vegetation tall enough to mark rendered grid-marking impractical. Instead, census routes were established by counting paces along compass bearings taken from distinct geomorphic features. Locations of singing males were mapped on graph paper while traversing the unmarked grid. An attempt was made to use different routes for each census visit to minimize bias related to time of day. Censuses began between 6:00 and 7:00 a.m., and generally took 3-4 hours to complete. Unless a species was observed at least 3 times within a site it was not included in calculations of species richness or densities; however, all species observed during census visits were recorded and I attempted to determine how each species was using each site. Species known to nest in alpine habitat were recorded as nesting within sites if nests with eggs or young, unfledged young, adults carrying food, and/or adults performing distraction displays during observer presence were observed. Also, species observed using sites repeatedly for foraging, but typically not known to nest in alpine habitat (and with no evidence of nesting observed), were included in the results. In 1989, each site was censused 8 times, with at least 3 days between visits at each site. weather. Censuses were conducted regardless of Fog, precipitation, and strong wind severely impeded visibility and/or hearing during censuses; also, defense of avian territories broke down during poor weather. Therefore, the first 3 censuses from 1989 (all conducted during severe weather) were dropped before results were calculated; the 5th 1989 census .at GT was dropped .. �282 for the same reason. through 10 July. Censuses in 1989 were conducted from 27 May After the 1989 census, it was determined that only 4 census visits were required to capture the highest counts, as long as they were conducted when weather was relatively clear and calm. Four census visits in 1990 were conducted at each site between 7 June and 1 August 1990, with at least 3 days between visits at each site. However, the last 1990 census from each site was dropped because breeding territories appeared to have broken down (birds were not singing or were not present) by then. For each census and species, densities were converted to pairs (and single male ptarmigan) per 20 ha site. Species densities within sites were averaged across census visits, for both breeding seasons. To determine species richness, numbers of species using sites for nesting and/or foraging were summed. .. RESULTS Overall avian species richness and density were greater at and TR than at MBC or GT, both years (Fig. 2-1). sa Species richness in 1989 and 1990 was 6.0 at MBC, 5.0 at GT, and 7.5 at both sa and TR. The average number of pairs (not including single ptarmigan males) across all sites was 32.5 in 1989 and 25.6 in 1990. Total pairs/20 ha, averaged across both years, was 23.2 at MBC, 29.4 at GT, 30.5 at sa, and 33.2 at TR. In 1989, densities of ptarmigan pairs at MBC and GT exceeded densities at either sa or TR (Table 2-1). numbers of single males and pairs. Also, MBC and GT had higher The total 1989 ptarmigan density for each site was 7.8 at MBC, 7.0 at GT, 2.0 at sa, and 1.5 at TR. �~ White-crowned Sparrow D White-tailed Ptarmigan Yellow-rumped Warbler (Z3 Wilson's Warbler 40 o Uncoln'sS trmmmmi • D Rock Wren Homed Lark American Pipit tSSl American Robin Mountain Bluebird 30 as s: 0 C\I -..... en 20 a:: « a. .. 10 o ~~~~~~~~~~~~~~~~~ 1989 1990 1989 1990 1989 1990 1989 1990 M8C GT S8 TR Fig. 2-1. Avian species composition and relative abundance at four sites (MBC=Medicine Bow Curve, GT~Gore Range Overlook, SB~ Sundance Basin, TR=Tombstone Ridge) in Rocky Mountain National Park, 1989 and 1990. Species using sites for nesting and/or foraging were included. �284 Table 2-1. Average densities (SE) of avian species breeding or foraging in alpine/krummholz habitat at 4 sites in Rocky Mountain National Park. Densities were ascertained during spot-map census visits during 1989 (n-5; n-4 at GT) and during 1990 (n-3). Pairs/20 ha Site GT SB MBC TR Species AMPIa Year 1989 1990 6.2 (0.68) 6.1 (0.53) 7.1 (0.96) 5.5 (1.80) 6.6 (0.55) 5.0 (1.00) 4.4 (0.88) 4.6 (0.61) AMROb 1989 1990 1.5 (0.50) 0.9 (0.00) 2.1 (0.60) 1.2 (0.00) 1.2 (0.84) 1.0 (0.00) 3.2 (0.74) 1.8 (0.61) HOlA 1989 1990 4.5 (1.29) 3.6 (0.91) 2.4 (0.96) 1.6 (0.70) 3.2 (0.84) 0.3 (0.58) 3.6 (2.18) 2.1 (0.94) LISP 1989 1990 1989 1990 ROWRC 1989 1990 WCSP 1989 1990 WIWA 1989 1990 WTPT 1989 1990 1.6 (0.55) 2.3 (0.58) 1.2 (0.84) 1.1 (0.76) 0.9 (0.00) 1.2 (1.64) 0.8 (0.47) 1.4 (1.22) 9.5 (1.65) 7.0 (0.53) 17.7 (3.96) 15.3 (4.24) 3.2 0.9 d 0.5 e 1.8 0.5 d 1989 1990 2.9 0.6 d 0.6 e 2.9 16.2 (1.64) 14.3 (2.89) 22.5 (2.64) 17.2 (1.61) 2.8 (1.30) 2.3 (1.53) 1.3 (0.88) 1.0 0.5 0.5 d 2.0 1.1 0.6 (0.58) aAMPI-American pipit, AMRO=American robin, HOlA=horned lark, LISPLincoln's sparrow, MOBL-mountain bluebird, RO'WR-rock wren, WCSPwhite-crowned sparrow, WIWA-Wi1son's warbler, WTPT-white-tai1ed ptarmigan, YRWA-ye11ow-rumped warbler. bObserved singing male and female, but no nest: species may have used sites for foraging, only. cObserved territorial male, but no female or nest. dSing1e territorial males. eSingle non-territorial males. '. �285 The total density for each site in 1990 was 4.1 at MBC, 5.8 at GT, 4.0 at SB, and 2.2 at TR. Interestingly, between 1989 and 1990 densities dropped at MBC/GT sites and increased at SB/TR sites. White-crowned sparrows (Zonorrichia leucophrys) were the most abundant birds at all sites (Fig. 2-1). Mean densities of sparrow pairs/20 ha ranged from 7.0 at MBC in 1990 to 22.5 at TR in 1989 (Table 2-1). While nests were not observed at all sites (1 nest was found at MBC and 1 at TR), frequent observations of adult sparrows carrying food into krummholz cover confirmed nesting at GT and SB. American pipits (Anrhus rubescens) were the second most abundant birds at all sites (Fig. 2-1). Mean densities of pipit pairs/20 ha ranged from 4.4 in 1989 at TR to 7.1 in 1989 at GT (Table 2-1). Three nests were observed at MBC, and 1 was observed at TR,. Adults carrying food were observed at GT and SB, confirming nesting of this species at all sites. Horned larks (Eremophila alpesrris) used all sites for nesting (Fig. 2-1). Mean densities of lark pairs/20 ha site ranged from 0.3 in 1990 at SB to 4.5 in 1989 at MBC (Table 2-1). An unfledged lark was observed being fed by an adult at MBC (the nestling had probably been frightened away from the nest by my disturbance or by elk that had just moved through the area), and adult larks were observed performing territorial and distraction displays throughout the breeding season at all other sites. American robins (Turdus migrarorius) used all sites for foraging, and possibly for nesting (Fig. 2-1, Tables 2-1 and 2-2). Territorial males were observed at SB and TR, although nesting was not confirmed. A robin nest was observed in a conifer between SB and TR �286 Table 2-2. Avian species observed using study sites during breeding season c~nsuses along Trail Ridge in Rocky Mountain National Park, 1989 and 1990. Sites were Medicine Bow Curve (MBC; 22 ha), Gore Range Overlook (GT; 17 ha), Sundance Basin (SB; 20 ha), and Tombstone Ridge (TR; 19 ha). Species American Kestrel (Falco sparverius) American Pipit (Anthus rubescens) American Robin (Turdus migratorius) Barn Swallow (Hirundo rustica) Brown-capped Rosy Finch (Leucosticte arctoa) Brewer's Blackbird (Euphagus cyanocephalus) Broad-tailed Hummingbird (Selasphorus platycercus) Cassin's Finch (Carpodacus cassinii) Chipping Sparrow (Spizella pallida) Clark's Nutcracker (Nucifraga columbiana) Common Raven (Corvus corvax) Dark-eyed Junco (Junco hyemalis) Gray Jay (Perisoreus canadensis) Hermit Thrush (Catharus ustulatus) Horned Lark (Eremophila alpestris) Lark Sparrow (Chondestes grammacus) Lincoln's Sparrow (Helospiza lincolnii) Mountain Chickadee (Parus gambeli) Mountain Bluebird (Sialia currucoides) Northern Flicker (Colaptes auratus) Pine Grosbeak (Pinicola enucleator) Pine Siskin (Carduelis pinus) Red Crossbill (Loxia curvirostra) Rock Wren (Salpinctes obsoletus) Ruby-crowned Kinglet (Regulus calendula) Swainson's Hawk (Buteo swainsoni) . Townsend's Solitaire (Hyadestes townsendi) Unidentified Flycatcher (Empidonax spp.) Unidentified Sparrows Western Meadowlark (Sturnella neglecta) Wilson's Warbler (Wilsonia pusilla) White-crowned Sparrow (Zonotrichia leucophrys) White-tailed Ptarmigan (Lagopus leucurus) Yellow-rumped Warbler (Dendroica coronata) MBC GT SB TR N F F F N N N F Fn Fn F F F F ~ f f f f f x F F F f f N x f f F f F F f N F f f N N N f F f F f F F F f f F f f f x f n f x f f x N N F N N F x x F x N N N N N N f n aN-nested within site (nest, adults with food, unfledged young, and/or distraction displays observed), n-nesting within site possible (territorial male observed), F-used site for feeding (observed taking food), f-foraging probable (bird flushed from vegetation or rocks), x-present as migrant or wandering beyond typical habitat (may have foraged but no evidence to substantiate). .. �LOI sites, however. Mean densities of robin pairs/20 ha ranged from 0.9 in 1990 at MBC to 3.2 in 1989 at TR (Table 2-1). Mountain bluebirds (Sialia currucoides) foraging (Fig. 2-1, Tables 2-1 and 2-2). used 3 sites for In 1990, a pair nested under the eaves of the Alpine Visitor's Center (pers. obs.), which was approximately 350 m from the southern boundary of the MBC study site. Mean densities of bluebird pairs/20 ha site ranged from 0.9 in 1990 at MBC to 1.2 in 1989 at SB and TR (Table 2-1). Lincoln's sparrows (Helospiza lincolnii) used SB only (Fig. 2-1). One nest was observed in 1990, and adults carrying food were observed at SB in 1989. Lincoln's sparrows were heard singing just below GT in dense willow carr (no willow carr was present within MBC or GT study areas), but none were recorded within the study sites either year. Mean density of pairs at SB was 1.6 in 1989 and 2.3 in 1990 (Table 2-1). Wilson's warblers (Wilsonia pusilla) used SB in both years and used TR in 1989 (Fig. 2-1). Mean densities of warbler pairs/20 ha ranged from 1.3 in 1989 at TR to 2.8 in 1989 at SB (Table 2-1). No Wilson's warblers were observed using MBC or GT sites, although they could be heard singing just below GT in dense willow carr. TR was the only site where yellow-rumped warblers (Dendroica coronata) were observed consistently (Fig. 2-1). At least one male incorporated a portion of TR into his territory during 1989. Mean density of warbler pairs/20 ha was 0.6 at TR in 1989 (Table 2-1). Yellow-rumped warblers were observed using all sites for foraging (Table 2-2), but not enough observations occurred during census visits to include them in species richness or density results. . �288 The rock wren (Salpinctes obsoletus) was the only other species observed consistently during census visits (Fig. 2-1). At least one male incorporated part of TR into his territory during 1989, and two males used TR during 1990. were ever observed. However, no females or evidence of nesting Mean density at TR was 0.8 in 1989 and 1.4 in 1990 (Table 2-1). Table 2-3 lists all species, including occasionals (observed < 3 times per site), using study sites during census visits. Although, occasionals were not included in species richness or density estimates, their activities were documented. DISCUSSION Species richness and total abundance were greater at SB and TR sites than at MBC and GT sites. Habitat differences among sites probably accounted for most of the observed differences among sites. Patches of tall conifer-dominated krummholz were more extensive at SB and TR than they were at MBC and GT (Melcher 1990); this could account for large differences in densities of white-crowned sparrows, which tended to prefer dense conifer-dominated krummholz. Moderately-sized discrete patches of shrub willows were more prevalent at GT and MBC, while extensive willow carr or tiny hedged willow patches were more prevalent at SB and TR (see Chapter 1, this volume); this might have influenced densities of ptarmigan, which preferred moderately-sized discrete patches of willow (see Chapter 3, this volume). Lincoln's sparrows, Wilson's warblers, and yellow-rumped warblers were found only at SB and TR in willow carr and tall conifer-dominated krummholz. Rock wrens are known to use alpine areas where appropriate rocky habitats occur (Collister 1970, Pattie and Verbeek 1966, Medin 1987), �and only SB and TR had such habitat. Most species observed only occasionally were probably nesting in near-by cliff or subalpine habitats, and used alpinejkrummholz habitats only for foraging or while travelling to other areas. Some occasional species were observed very early or late in the breeding season and were probably migrants, non-breeding adults, or dispersing juveniles. Fewer species and lower bird densities were observed in 1990 than in 1989. The 1989 sampling period may have concentrated observations during peak territorial activities when birds were more vocal and were more likely to be counted. In 1990 the sampling period was extended further into the summer than it was in 1989, and may have been more representative of post-dispersal densities rather than breeding densities. While the 4th 1990 census was dropped to correct for dispersal effects, the 3rd census may have been somewhat effected as well. Also, I had determined previously that 4 counts were necessary to capture highest counts; lower density estimates in 1990 may have resulted from the smaller sample size. Little research has been done to determine typical densities of alpine species in Rocky Mountain alpinejkrummholz habitats, so comparisons between RMNP study sites and other alpine areas in the southern Rocky Mountains are few. Pattie and Verbeek (1966) described species observed on Beartooth plateaus (in the Beartooth Mountains, Montana and Wyoming), but densities of birds were not included. Densities of American pipits were lower on Trail Ridge than those found in the Beartooth Mountains, which were estimated at 10 pairs/20 ha by Verbeek (1970); Verbeek (1967) found 15 lark territories on 116 ha, approximately 2.59 pairs/20 ha, similar to lark densities on Trail Ridge. However, our results may not be very comparable. Verbeek's �290 study areas included alpine meadow habitat, only, while my study areas included alpine meadow, krummholz, carr, rocky outcrops, and windswept ridges. Therefore, densities of larks and pipits on Trail Ridge may have been similar to, or even higher than, those on Beartooth Plateau. Densities of American pipits were somewhat higher on Trail Ridge than in alpine regions of the Sierra Nevada (Medin 1987); Medin found 3.5-3.7 pairs of (water) pipits/20 ha. Species richness on Trail Ridge was considerably higher than it was in the Sierra Nevada; I found at least 7 nesting species while Medin found from 1-2 nesting species. Also, total pairs (all species)/20 ha were greater on Trail Ridge (23.2-33.2 versus 3.7-5.2) than in the Sierra Nevada. The differences between my results and those of Medin were probably due to large differences in associations/vertical structures of vegetation. Also, Medin's study area was over 40% rock-covered, whereas my study areas were considerably less rock-covered. He also stated that little, if any, grazing/browsing by domestic livestock had ever occurred in his study area (although he makes no mention of wild ungulates). If intensive browsing or grazing alters vegetation (and subsequently avian species diversity and/or abundance), then some of the differences cited above may have been attributable to effects of ungulates activities in RMNP. It is possible that grazing and browsing by wild ungulates enhances habitat for some birds, while degrading habitat for other species. Wild ungulates, especially elk, grazed and browsed extensively throughout the study sites during all seasons (see Chapter 1, this volume), and they undoubtedly shortened or perpetuated shortness of vegetation to some extent. Ungulates also trampled vegetation in willow and/or conifer-dominated krummholz, creating .. �L~l and/or perpetuating open areas, with very short or sparse vegetation surrounded by tall vertical cover. Most ptarmigan stayed in or near krummholz dominated by shrub willow. May and Braun (1972) found that ptarmigan forage on buds and twig tips of willows throughout the year. I observed ptarmigan foraging frequently on willows along willow-patch perimeters. Where trampling by elk perpetuated or left unchanged the "patchiness" of willow, ptarmigan foraging habitat probably was unaffected. However, where activities of elk altered patch dimensions (height and/or perimeter:area ratio) of willows, and/or where elk diminished canopy cover of shrub willow, then available willow-food resources for ptarmigan probably were diminished (see Chapter I, this volume). It is unlikely that changes to vertical structure affected ptarmigan cover. When alarmed, ptarmigan generally used "freeze" behavior to enhance their best cover: cryptic plumage. Also, vertical cover is not necessary for ptarmigan-nesting sites (Giesen et al. 1980), although a majority of hens nest where there is some vertical cover (geomorphic, topographic, or vegetative) to shield them from prevailing winds. White-crowned sparrows used conifer-dominated cover more than any other, although observed nests were located in willow and under an overhang of sod on the ground in an opening between patches of conifer. Generally, tallest branches of dwarf-conifers were used as perches for singing and for surveying territories. Elk never were observed foraging on conifers, so it is unlikely that perches used by sparrows were diminished by elk activities. Sparrows spent much time feeding in open areas between krummholz patches, where vegetation was shorter than sparrow height and sometimes quite sparse. ~ Sparrows fled .. �292 to adjacent conifer (and sometimes willow) cover when alarmed. While more conifer-dominated krummholz occurred at SB and TR sites, possibly explaining greater densities of white-crowned sparrows at those sites, it is possible that preferred sparrow habitat was maintained or increased as a result of elk activities. There is evidence indicating that elk activities have been greater at SB and TR sites (see Chapter 1, this volume). Robins used habitat much as white-crowned sparrows did, and changes in vegetation caused by browsing would be expected to have similar affects on robins and white-crowned sparrows. American pipit territories were generally located in open turf or meadow, although some used areas broken up by small patches of krummholz and/or large rocks from which they often surveyed their territories. Grazing and browsing by ungulates could perpetuate or create habitat preferred by pipits. Observed nests were situated under small overhangs of sod in fairly short dense turf (sedges, grasses, and cushion plants). In most cases, pipits were observed foraging in areas where vegetation was dense but roughly pipit height or shorter. However, if ungulate activities were to become so intensive that bare ground became prevalent, pipit habitat would be degraded. When alarmed, pipits almost never used vegetation cover, so it's unlikely that altered krummholz vegetation would affect pipits. Generally, larks used high wind-swept areas where vegetation (primarily cushion plants) was shorter than lark height and where little patches of bare, gravelly soil were common. It isn't likely that vegetation in lark habitat is suitable for foraging ungulates. Ungulates used lark habitat during travel, though, and the resulting trampling, coupled with wind effects, may perpetuate lark habitat by keeping succession in check. Larks never were observed using ~ .. �vegetation cover when alarmed. Therefore, intensive foraging activities of elk are not likely to affect larks. Pairs of mountain bluebirds foraged together, usually selecting areas where vegetation was shorter than bluebird height. Use of alpine tundra for foraging by bluebirds may have been preferred early in the breeding season when alpine areas were more snow-free than adjacent sub-alpine areas. Bluebirds were not seen as frequen~ly later in the breeding season. Hovering behavior was frequently observed while bluebirds foraged, probably because suitable dead snags from which to watch for invertebrate prey were few at most study sites. When alarmed, bluebirds used various escapes: flying short distances to open ground, flying short distances to tall rocks, or flying off sites altogether. were used. More rarely, dead snags in vegetation As long as invertebrate populations are not affected significantly by activities of ungulates, it isn't likely that .. bluebirds would be affected by intensive use of alpine tundra by ungulates. Lincoln's sparrows nested and were assumed to forage in willow carr (usually < I m high). willow carr (usually> high). heights. Wilson's warblers (Wilsonia pusilla) used I m high) and dense krummholz (usually> I m Yellow-rumped warblers used dense krummholz of various When alarmed, Lincoln's sparrows and both warbler species generally skulked within or flew to adjacent patches of dense krummholz cover; eventually, sparrows and yellow-rumped warblers would "tee-up" on tall perches to survey their territories, while Wilson's warblers generally remained concealed. If activities of ungulates were to fragment and/or diminish (heights or diameters) stands of carr �294 or krummholz, densities of Lincoln's sparrows and both warbler species could decline. In conclusion, there are numerous changes that could be inflicted on vegetation by ungulates in alpine/krummholz habitat. The possible changes could subsequently alter avian-community structure. Long-term monitoring would be a non-destructive method for evaluating effects of wild-ungulate activities in National Parks. questions to ask would be: Some important 1) are ungulates maintaining, retarding, or changing community associations and/or vegetation structure; 2) if structural changes are occurring in plant communities, how does that affect snow cover, what are the consequences of altered snow covers, and on what level of landscape would those consequences be realized, 3) how do avian communities respond over time to changes in habitat, and 4) how do similar communities outside Park boundaries compare to those inside Park boundaries? Answers to these questions could steer future decisions regarding management of wildlife on public lands and acquisitions of adjacent lands that could preserve or restore the integrity of Park ecosystems. As National Parks become more like islands of habitat in a fragmented landscape, high densities of wild ungulates within Park boundaries will continue to pose a threat to the very communities that Parks are supposed to preserve. LITERATURE CITED Bailey, A. M., and R. J. Niedrach. 1965. Birds of Colorado. Vols. I and II. Denver Mus. Nat. Hist., Denver, CO. 895pp. Bear, G. D. 1989. Seasonal distribution and population characteristics of elk in Estes Valley, Colorado. Colo. Div. Wildl. Spec. Rep. 65. l4pp. .. �_____ , G. C. White, L. H. Carpenter, R. B. Gill, and D. J. Essex. 1989. Evaluation of aerial mark-resighting estimates of elk populations. J. Wildl. Manage. 53:908915. Braun, C. E. 1969. Population dynamics, habitat, and movements of white-tailed ptarmigan in Colorado. Ph.D. Diss., Colorado State Univ., Fort Collins. l89pp. 1980. Alpine bird communities of western North America: Implications for management and research. Pp. 280-291 in Workshop Proc. Management of western forests and grasslands for nongame birds. (R.M. Degraff and N.G. Tilghman, compilers). U.S. Dept. Agric., For. Servo Gen. Tech. Rep. INT-86. _____ , R. K. Schmidt, Jr., and G. E. Rogers. 1973. Census of Colorado white-tailed ptarmigan with tape-recorded calls. J. Wildl. Manage. 7:90-93. _____ , and K. M. Giesen. 1989. Population dynamics of whitetailed ptarmigan, Job Progress Rep., Colorado Fed. Aid Project W-152-R. Apr. 1989. 245pp. _____ , and 1990. Population dynamics of white-tailed ptarmigan, Job Progress Rep., Colorado Fed. Aid Project Wl52-R. Apr. 1990. 264pp. _____ , D. R. Stevens, K. M. Giesen, and C. P. Melcher. 1991. Elk, white-tailed ptarmigan, and willow relationships: a management dilemma in Rocky Mountain National Park. Trans. 56ch N. Am. Wildl. and Nat. Res. Conf .. Wildl. Manage. Institute. Butler, D. C. 1979. Effects of a high-density population of ungulates on breeding bird communities in deciduous forest. M.S. Thesis, Colorado State Univ., Fort Collins. 67pp. Collister, A. 1970. An annotated checklist of birds of Rocky Mountain National Park. Museum Pictorial No. 18, Denver Museum of Natural History. 64pp. Giesen, K. M., C. E. Braun, T. A. May. 1980. Reproduction and nest-site selection by white-tailed ptarmigan in Colorado. Wilson Bull. 92:188-199. International Bird Census Committee. 1970. Recommendations for an international standard for a mapping method in bird census work. Audubon Field Notes 24:722-726 Jackson, S. 1991. Changes to bird communities from grazing by wild ungulates. Proc. Ecol. Soc. Am. Johnson, R. E. 1966. Alpine birds of the Little Belt Mountains, Montana. Wilson Bull. 78:225-227. �296 Kingery, H. E., (ed.). 1988. Colorado bird distribution latilong study, 3rd edition. Colorado Division of Wildlife, Denver. 81pp. Knopf, F. L., J. A. Sedgewick, and R. W. Cannon. 1988. Guild structure of a riparian avifauna relative to seasonal cattle grazing. J. Wildl. Manage. 52:280-290. Marr, J. W. 1967. Ecosystems of the east slope of the Front Range Colorado. Univ. Colorado Ser. BioI. 8. 134pp. May, T. A., and C. E. Braun. white-tailed ptarmigan 36:1180-1186. Medin, in 1972. Seasonal foods of adult in Colorado. J. Wildl. Manage. D. E. 1987. Breeding birds southern Snake Range, Nevada. of an alpine habitat in the Western Birds 18:163-168. Melcher, C. M. 1990. Avifauna responses to grazing, Job Progress Rep., Colorado Fed. Aid Project W-152-R. Apr. 1990. 264pp. Myrberget, S. 1987. grouse breeding The effects of sheep grazing habitat. Fauna 40:144-149. on a willow Olmsted, C. E. 1979. The ecology of aspen with reference to utilization by large herbivores in Rocky Mountain National Park. Pp. 87-89 in M. S. Boyce, and L. D. Hayden-Wing, eds. North American elk: ecology, behavior, and management. Univ. Wyoming, Laramie. Pattie, D. L., and N. A. M. Verbeek. 1966. Alpine Beartooth Mountains. Condor 68:167-176. Ryder, birds of the R. A. 1980. Effects of grazing on bird habitats. Pages 51-64 in Management of western forests and grasslands for non-game birds. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. INT-86. Stevens, D. R. 1980a. The deer and elk of Rocky Mountain National Park: a ten-year study. U.S. Dep. Inter., Natl. Park Servo Rep. ROMO-N-13, Estes Park, CO. 163pp. 1980b. Effect of elk on alpine tundra in Rocky Mountain National Park. Pp. 228-241 in C. L. Jackson and M. N. Schuster, eds. Proc. High Altitude Revegetation Workshop 4. Colorado State Univ. Infor. Series 42. Taylor, D. M. 1986. Effects of cattle grazing on passerine birds nesting in riparian habitat. J. Range Manage. 39:254-258. Tucker, T. L. 1987. Cattle grazing affects nongame wildlife populations and fish habitat in a,montane riparian area. M.S. Thesis, Colorado State Univ., Fort Collins. 84pp. .. �297 Verbeek, N. A. M. 1967. Breeding biology of the horned lark in alpine tundra. Wilson Bull. 79:208-217. 1970. 451. Breeding ecology of the water pipit. Weber, W. A. 1976. Rocky Mountain Flora. Univ. Press, Boulder. 479pp. Auk 87:425- Colorado Assoc. Willard, B. E., and J. W. Marr. 1970. Effects of human activities on alpine tundra ecosystems in Rocky Mountain National Park, Colorado. BioI. Conserv. 2:257-265. Zwickel, F. C. 1972. Some effects of grazing on blue grouse during summer. J. Wildl. Manage. 36:631-634. . �298 CHAPTER :3 ACTIVITY BUDGETS AND REPRODUCTIVE SUCCESS OF FEMALE WHITE-TAILED PTARMIGAN IN ELK-IMPACTED HABITAT INTRODUCTION In Colorado, white-tailed ptarmigan (Lagopus leucurus altipitens) occupy alpinejkrummholz and subalpine habitats that contain willow (Salix spp.) (Bailey and Niedrach 1965, Braun and Rogers 1971). Wintering areas must include willows that remain at least partially emergent above the snow (Braun 1971, Braun et al. 1976) because the birds forage almost exclusively on buds and terminal leaders of willow from late autumn to early spring (May and Braun 1972). Breeding territories also include shrub and/or mat-forming willows (Braun 1971, Giesen et al. 1980, Schmidt 1988). Ptarmigan continue to forage on willow buds and terminal leaders through the breeding season; in addition, leaves and catkins are eaten once they have emerged (May and Braun 1972). Breeding season in the alpine is compressed by climate (Giesen et al. 1980). A ptarmigan hen must delay nesting until she has molted into breeding plumage and suitable nest sites have become snow-free. However, nesting must begin soon enough to ensure an ample growth period for juveniles prior to onset of winter. Furthermore, early nesting increases a hen's potential for renesting if the first clutch is destroyed (Giesen and Braun 1979b, Parker 1981). Therefore, between mid-May and late June, when a full molt and egg production .. �occur, a ptarmigan hen must meet significant nutritional demands. To a large extent, willows provide the nutrients necessary to meet those demands (May 1975). Researchers have suggested that a ptarmigan hen bases her selection of a mate on how much willow his territory contains (Choate 1963, Watson and O'Hare 1979, Giesen et a1. 1980, Schmidt 1988). Also, Schmidt (1988) found evidence that ptarmigan hens, especially yearling hens, may "sample" potential breeding territories prior to settlement, possibly to avoid settling where food resources are inadequate. Because ptarmigan heavily depend on willow for food, declines in breeding densities of ptarmigan probably would occur in areas where willow also had declined. Heavy browsing and/or grazing by large ungulates has been shown to cause changes in habitat structure and vegetative communities, which in turn causes lower densities (or complete elimination) of certain avian species (Zwicke1 1972, Butler 1979, Ryder 1980, Taylor 1986, Myberget 1987, Tucker 1987, Knopf et al. 1988, Jackson 1991). A similar phenomenon may have occurred on Trail Ridge in Rocky Mountain National Park (RMNP), Colorado, where breeding densities of white-tailed ptarmigan have declined (Braun and Giesen 1990). Population levels of elk (Cervus elaphus) in RMNP were controlled until 1968 when the National Park Service discontinued control efforts (National Park Service 1975, 1988). elk population increased rapidly. Subsequently, the Estimates of elk densities in the RMNP-Estes Valley area (Stevens 1980a, Bear et al. 1989) indicated that the population had exceeded the winter carrying capacity (Hobbs et al. 1982) by the early 1980s, and was at least twice the carrying capacity by 1990 (Braun et al. 1991). Elk-inflicted damage to vegetation, especially species belonging to the Sa1icaceae family, in . �300 and around RMNP was reported by the late 1970s (Olmsted 1979; Stevens 1980a, 1980b). Ptarmigan habitats were among those being used by increasing numbers of elk for greater periods of time (Stevens 1980b, Bear 1989). Braun et al. (1991) hypothesized that heavy damage to willow in ptarmigan habitats had been caused by elk, which led to declines in breeding densities of ptarmigan on Trail Ridge in RMNP. Braun et a1. (1991) reported long-term declines in canopy cover of willow and in breeding densities of ptarmigan as elk densities increased. Melcher (Chapter 1, this volume) reported that areas in which breeding densities of ptarmigan had declined most were characterized by significantly higher densities of elk feces (pellets and chips), more browsing damage to willows, and lower abundance of willow-food resources. In response to diminished or degraded food resources, ptarmigan densities could decline through several mechanisms: HI Males experience poor survivorship, resulting in vacant territories. H2 Females select against resource-poor territories, resulting in reduced fitness among territory-holding males and leaving no male recruits to replace aged/deceased territory-holders, and/or males may avoid recruiting to resource-poor territories. H3 Females settle on resource-poor territories where they must spend more time searching for and traveling to food patches, which could result in poor production and/or poor rates of return in subsequent breeding seasons. Because manipulative experiments are not allowed in National Parks, I was unable to conduct experimental tests of these hypotheses. Thus, I conducted a pilot study to evaluate hypotheses relevant to the third hypothesis. Caraco (1980) and Weathers and Sullivan (1989) have shown that the amount of time allocated to foraging by birds can be �301 explained by their nutritional with reproduction. demands status and by energy costs associated Because ptarmigan associated hens must meet high nutritional with molt and egg production within 1968, May 1975, Thomas and Popko 1980, Moss and Watson assumed that difficulties through their foraging behavior. prey intake in procuring (bite rate) depends, Holling demonstrate responses and live unbrowsed of mitigating terminal ptarmigan I assumed to their "prey" hens settling supplies food supplies, of willow. in areas where elk-use as well as would (willow buds If hens are incapable fitness would be poor as compared with adequate that that ptarmigan densities. the effects of inadequate that their inclusive territories leaders) I (1959) demonstrated in part, on prey density, time. functional 1982), then I assumed to hens using I predicted that and elk-inflicted damage to willow was greatest would spend more time foraging search and travel time), have lower bite rates items), and/or experience poor reproductive hens using sites with less elk-inflicted that inclusive fitness values chicks fledged) they budgeted and distances (West enough food would be manifested search time, and food-handling similar 3-5 weeks (more (lower density success when compared damage. .. of food to I also predicted (pre and post-nesting weights, moved by hens would be related number of to time to foraging. STUDY SITES Several historical breeding and/or current season, communities, southeast criteria were used for site selection, and occupancy 2) presence including willows. by white-tailed including ptarmigan of alpine and krummholz 1) during vegetation- Two study sites were selected (SE) region of Trail Ridge, and two study ·sites were in the �302 selected in the northwest (NW) region of Trail Ridge. At SE sites breeding densities of ptarmigan had declined most, elk-use was significantly greater, characteristics of willow indicative of heavy browsing by ungulates were significantly greater, densities of willow buds and terminal leaders were lower, and percent covers of willows (both shrub and prostrate) were lower than they were at NW sites (see Chapter I, this volume). SE study sites were Sundance Basin (SB) and Tombstone Ridge (TR), NW study sites were Medicine Bow Curve (MBC) and Gore Turnout (GT) (approximately 105°45' W long and 40°26' N 1at). Site boundaries were determined by taking compass bearings from distinctive geomorphic and topographic features. Boundaries were plotted on U.S. Geological Survey maps (scale 1:24000), and site areas were determined by using a planimeter. Approximate areas were: MBC 22 ha, GT - 17 ha, SB - 20 ha, TR - 19 ha. Elevations ranged from 3475 to 3660 m. Climate and community associations typical of Front Range a1pine/krummho1z communities were described by Marr (1967). Community types (after Braun 1969) and plant species (after Weber 1976) common throughout all sites were: Trifolium cushion fe11fie1d; Dryas oc~ope~ala hookeriana Juz. and/or Dryas-Salix (S. nivalis Hook.) turf; alpine meadow comprised of Kobresia, Carex, Trifolium, Poa, and/or Acomas~ylis rossii R. Br. (formerly Geum rossii R. Br.); snow accumulation areas comprised of Ar~emisia, Carex, Poa, and/or: Acomas~ylis; and patches of krummho1z comprised of Salix spp. (S. planifolia Pursh, S. brachycarpa Nutt.), Picea engelmanii Parry, and/or Abies lasiocarpa Hook. Communities more typical of dry wind- swept areas (Dryas and Kobresia turf) dominated sites at MBC and GT, and communities more typical of moist snow-accumulation areas (Carex .. �303 and Artemisia) greater dominated sites at SB and TR. detail in Chapter Sites were described in 1 (this volume). METHODS Selection of Hens Two methods were employed sites: 1) methodically recordings traversing of male challenge 1973), which elicited 2) tracking birds of a long-term to locate all ptarmigan study sites while playing calls and flight screams responses from territorial study (Braun and Giesen using study sites had been banded by Colorado personnel. Use of color-band identifications of individuals From 15 through sites were monitored near those areas. breeding from unobtrusive to ascertain If known pairs season) were observed, ptarmigan unique of Wildlife to each bird allowed for breeding attempts they would maintain were made to observe their pair-bond status. separated by at least five days·, in mid to late May were assumed establishing Schmidt on at least two occasions, a pair bond for the 1990 breeding 1969). established together in or as a pair during the 1989 (unbanded prior to spring 1990) to ascertain Pairs observed As part found using the study it was assumed Repeated birds. distances. their potential (observed and 1990), all ptarmigan Division 22 May, 1990, ptarmigan site and mate fidelities. unknown combinations taped (Braun et al. males, in fresh snow to detect unresponsive population using study By late May, three established season of the 12 pairs were captured fitted with radio 4-g transmitters, their capture sites. Transmitters weighed (based on and/or potentially pairs at each site had been selected Females to be for intensive study. on 23 or 29 May, 1990, (± 5 g), then released at were fitted just below ~ the hens' �304 crops with 7 em black-elastic match breeding plumages; and transmitter neck bands, and were painted the batteries had 4 month brown to life expectancies, ranges were 400 m to 5.0 km, depending on topography and weather. Pre-Nesting Activity Budgets From 24 May through (Altmann budgets of Hens 30 June continuous 1974) was conducted of radio-marked to quantify pre-incubation hens. Attempts at least once every other day. Behavior one hour long, except when terminated weather or intolerance stratified focal-animal of observers by period of day: sampling activity were made to observe samples (observations) prematurely by hens. each hen were due to severe Observations were dawn to 1029, 1030 to 1459, and 1500 to dusk. Initially, sites were visited sites were selected been observed considerably of the behavior number selecting so that activities Hen behaviors (interpreted observer, By mid June, however, more often than others. some hens had For the remainder and locating hens, observers (unless another the intimidation (i.e., displacement behavior) factor clearly data were not collected them. disturbance displays, away from rapid feeding and/or constant caused the disturbance). until the hen appeared distances varied themselves disturbing 1969) were running or creeping vocalizations, Observer-hen situated without to indicate observer-induced from Schmidt while on alert to equalize made per hen per time period. of hens could be discerned assumed warning the observer. and hens within study, hens were chosen systematically of observations After budget randomly. systematically, vigilance Activity undisturbed from approximately by �JVJ 5-100 m, depending on tolerance by hens, concealment afforded by proximal geomorphic/vegetational structures, and weather. Digital lap-timer stop watches, with cumulative-time capability, were used to measure the amount of time hens spent in each subsequent activity during I-hour sample periods. Activities and times budgeted to them, weather, location, general activities of males, foods eaten (when discernable), bite rates, and distances hens moved were recorded during each sample observation. Behaviors recorded were: feed, sit (including rest, sleep), alert, maintenance (preen, bathe, scratch, yawn), nest (build nest, lay/cover eggs), court (including copulation), aggression (towards other ptarmigan), locomotion (when not associated with an ultimate behavior), and out of view. When a "proximate" behavior appeared to be associated with an "ultimate" behavior (e.g., walking or running associated with foraging or courtship, respectively), only the ultimate behavior was recorded. However, to eliminate ambiguities protocols were used as follows: walking at the start of an observation period (i.e., possibly no frame of reference to determine ultimate behavior) was recorded as walking; walking between unrelated activities (e.g., dust bathing, resting, or feeding) was recorded as walking; walking preceded by feeding was recorded as feeding for up to 15 additional seconds after feeding had stopped, and if by that time feeding had not resumed and/or was followed by an unrelated behavior, then walking was the behavior recorded. However, to account for the possibility that continued walking ( >15 seconds) actually represented long search times for food or great distances between food patches, walking was recategorized as feeding if feeding resumed within five minutes and no other behavior was apparent during the five minutes. Occasional bites or a series of .. �306 rapid bites assumed taken during disturbance to be "displacement" recorded as alert. of view. of visible to feed then behavior allowed. Behavioral incubating behavior parts of shrubs was recorded indicated as feeding, June through hatching were recorded of further success, for each hen. nesting not out if 1) shrub willow through the success (late Dates of clutch initiation, fledging that on each hen until she began to assess her reproductive late August). success, as Then, each hen was monitored and brood seasons being also. studies were conducted her clutch. was shrubs, hens were out of Food types eaten, categorized 2) other, were recorded nesting with ultimate When hens were feeding, bite rates were recorded visibility or behavior, While feeding on willow view often, but if motions hens continued and/or extreme vigilance attempts, and predation clutch type/failure After nesting failure as determined by subsequent non-breeding areas) or fledging transmitters were removed, sizes, dates (and no possibility movement of chicks, hens were recaptured, then hens were weighed to radio and released. Data Analysis It was reasoned experience effects of disturbance observer-influenced minutes that a recently-disturbed disturbance of each observation hen might even after outward had ceased; to signs of therefore, period were dropped continue the first 10 to further reduce the l possibility (recommended of including observer-influenced by B. Van Horne, pers. comm.). spent out of view was dropped, activity category in view during behavior Also, time that hens and total time budgeted was calculated as a percentage each sample period. data to each of total time spent .. �~VI Early breeding hens, chicks regressed feeding season weights (when radios were applied) fledged per hen, and distances (GLM Procedure, moved by hens were SAS 1988) against percentages (by observation). of time spent Date, hen age, date of clutch number of eggs laid, period of day (and the corresponding term), weather Percentages subjected between factors, and observer were all treated of time spent feeding were averaged, to a one-tailed NW and SE regions activities t-test to ascertain of Trail Ridge. were summarized. to ascertain differences initiation, quadratic as covariates. by hen, then differences Percentages Also, one-tailed in weights of (P <0.05) of other t-tests were conducted and ages between hens using SE versus NW regions. Bite rates observation, (by food type) were averaged within then averaged by hen and subjected (P for differences each sample to one-tailed <0.05) between regions of Trail Ridge. for average bite rates per hen were treated as missing t-tests Zero values data. RESULTS and DISCUSSION Activity Budgets Reported otherwise data represent indicated), (unless otherwise but represent indicated) from the study sites before them. Subsequent reproductive relocations success activity, (Table 3-1). followed because (unless only three hens at SE sites three SE hens moved 4-13 km away any behavior data had been collected of hens allowed assessment from of for all but one hen. Most hens budgeted activity all six hens at NW sites more time to feeding Sitting was generally by maintenance activities. than to any other the second most common Mean.time spent feeding �w o CO Table 3-1. Mean activity budgets (percent of time in view during a sample period) for 9 female white-tailed ptarmigan during pre-nesting season in Rocky Mountain National Park, 1990. Hens 9, 11, and 12 disappeared after being radio-marked. Number of sample periods (n) and total minutes (min) observed (in view) are given. ActivitvA Site Hen (bands) n (min) Feed Sit Maint Nest Alert Locom Court A££ress MBC 1 2 3 (RYYR) (RBBW) (RBYG) 15 9 14 (630.9) (374.8) (492.3) 5l.8 79.5 59.3 24.4 11.6 15.8 13.1 4.5 7.9 5.0 0.0 6.9 2.7 2.9 4.7 2.9 l.2 6.3 0.0 0.0 0.0 0.0 0.0 0.0 GT 4 5 6 (RYWG) (RWRW) (RGGW) 16 15 13 (646.6) (637.1) (571.9) 53.8 4l. 2 39.1 25.7 30.2 33.1 4.9 12.2 14.9 12.5 6.7 9.2 l.0 6.9 l.8 l.7 2.7 l.8 0.0 0.0 0.0 0.0 0.2 0.0 SB 7 8 (RBBR) (RGRY) 12 7 (487.9) (280.7) 58.0 23.7 30.7 43.8 8.1 2.7 0.0 14.1 l.1 5.4 0.5 0.4 0.0 14.3 0.0 0.0 TR 10 (RBRG) 8 (385.5) 39.6 27.6 16.0 12.4 2.6 l.7 0.0 0.0 Feed-search for and handle food. Sit-sit/rest/sleep. " Maint-preen/bathe. Nest-build nest/lay egg/cover eggs. Alert-vigilance/head up/frequent looking up or behind/hiding/creeping/running. Locom-walk/run/f1y. Court- court/chase/copulate. Aggress-aggression (towards any ptarmigan besides own mate) . a .. �by NW and SE hens was 54.1% respectively. ± Time hens budgeted 17.2 (n - 3), to feeding did not differ between 7). NW hens tended to budget more time to feeding hens did, which was opposite original core hypothesis, declined in response necessarily falsified indicator Although to predicted that breeding to declines densities in willow-food territory of food supplies breeding no previously-used season (and subsequent territories early in the breeding selection by yearling than time hens budget significant departures) to feeding. hens would have territories), hens on 1988). If yearling (and subsequently hens do avoid then it may be biologically hens found using SE sites early in the breeding season subsequently left those sites. settling at SE sites due to inadequate (and if hens don't make mistakes Therefore, season could be, in part, attempts prior to settlement that three yearling then differences hens may be a that they used in of yearling (Choate 1963, Schmidt on inferior had was not to which they could return. appearances sample territories the of ptarmigan (Schmidt 1988), yearling territories to assess resources However, resources, adult hens tend to return to territories the preceding settling results. than SE by these results. As stated earlier, better of Trail Ridge (0.10 < P < 0.15; df - significantly However, regions ± 14.6 (n - 6) and 40.4% They may have avoided supplies of willow. in their assessments in time spent foraging If true of resources) among hens would not have been expected. Bite Rates Mean bite rates of hens on shrub willow sites (within regions), did not differ between so hen was used as the error term when testing .. �310 for regional differences in bite rates on shrub willow. However, between-site differences (within regions) were found for bite rates on other foods, in which case site was used as the error term. Hens 1 (MBC) and 10 (TR) were not observed eating shrub willow, and hen 3 (MBC) was not observed eating other foods, which are reflected in sample sizes reported. I had expected that hens would exhibit functional responses to lower densities of food (buds and terminal leaders of willow and/or other food items) through lower bite rates. However, bite rates of hens feeding on shrub willow did not differ (P >0.10) between regions: bite rates/min were 33 f 8.4 (n - 5) and 31 SE hens, respectively. ± 13.7 (n - 2) for NY and Bite rates of hens on other foods (including mat willow) were similar (P >0.25) between regions as well: bites/min were 58 ± 7.3 (n - 2) and 51 ± 12.1 (n - 2) for NY and SE hens, respectively. Bite rates may have been similar for the same reason that foraging budgets were similar: hens may have avoided settling where food densities were inadequate, in which case differences in bite rates would not have been expected. SB hens had the lowest bite rates on other foods (39 and 45 bites/min). NY hens, however, had bite rates of 53-64 bites/min (average was 59) on other foods. Interestingly, the bite rate of hen 10 at TR also was 59 bites/min on other foods. Occurrence of mat willow may have been a main factor influencing these enigmatic results. Mat willow occurred on almost every transect examined in territories used by NY hens and the TR hen, but no mat willow occurred in territories used by SB hens (see Chapter 1, this volume). Although I was never sure when ptarmigan were eating mat willow, subsequent investigations of areas used for feeding on other foods, especially > .. �where bite rates had been high, often revealed presence of mat willow. May and Braun (1972) indicated that mat willow was eaten by ptarmigan, but they did not differentiate proportions of various willow species eaten. Mat willow may have constituted a greater portion of ptarmigan diets than previously believed. If true, and if mat willow escaped damage by foraging elk (too prostrate for elk to bite), then occurrence of mat willow could have accounted for highest bite rates for NY and TR hens, and may have mitigated declines in shrub-willow. This would explain, in part, why ptarmigan densities at NW sites have declined less than those at SE sites. Although elk impacts appeared to be lighter at NW sites, it did appear that shrub willows were damaged there as well. Bite rates on shrub willow (using data for all hens) were significantly greater than bite rates on other foods: 55 ± 9.2 bites/min on other foods versus 33 ± 8.9 bites/min on shrub willow (P - 0.0004; df - 13). The difference was probably due to slower rates of "attack" (longer handling times) when hens fed on shrub willow. When pecking at other foods on the ground, hens did not appear to hesitate between bites, However, when feeding on shrub willow, a relatively long time was spent "aiming at" and "twisting off" buds and tips of terminal leaders. Measures of Fitness Weights and reproductive success of hens are summarized in Table 3-2. 7 chicks. Only 1 hen (hen 2 at MBC) was successful: she fledged 4 of All nest failures were the result of predation, either avian (strongly suspected when hen 4 lost her 1st clutch) or mammalian (strongly suspected when hen 10 lost her clutch). Causes of other �w ~ N Table 3-2. Reproductive success and weights for 3 white-tailed ptarmigan hens/4 sites in Rocky Mountain National Park, 1990. MBC hens 1-3; GT hens 4-6, SB hens 7-9, and TR hens 10-12. Hens 9, 11, and 12 left sites shortly after release; hen 9 was not seen again, hens 11 and 12 were relocated after nesting season to remove transmitters and ascertain reproductive success. Hen 6 moved out of transmitter range, died, or her radio failed, 2 days after loosing her brood. Known-age (as of 15 July 1990) hens denoted with u_u; unknownage hens denoted with u+u; all unknown-age hens were ~ 3 years old by 15 July 1990. Dates are Julian. HEN AgeR 1 RYYR 3- 144 212 390 325 -65 165 200 2 RBBW 1- 144 241 420 370 -50 157 3 RBYG 1- 144 216 400 350 -50 165 4 RYWG 3- 150 212 420 375 -45 171 5 6 RWRW RGGW 3+ 3+ 150 150 212 410 420 380 -30 172 169 201 7 RBBR 1- 144 212 390 380 -10 171 196 "8 RGRY 2- 144 212 405 365 -40 162 193 RBYY RBRG RBRW RBYR 1111- 144 144 144 144 215 215 219 385 385 360 345 370 355 360 -15 -05 +15 165 9 10 11 12 Cap Rcp WtB WtA Chg ? ? XHc D1e D2C 100 2 6 191 100 7 57 194 100 5 o o 6 o 6 871 8 o 1001 6 o 100 6 o o 6 1 1 1 ? CIn ? ? Hch o 4 1 1 o o XFl Notes 1st clutch disappeared before completion. All chicks from 2nd clutch disappeared w/in 5 d of hatching. 3 chicks disappeared w/in 14 d of hatching. All chicks disappeared w/in 7 d of hatching. 1st clutch destroyed @ 14 d (avian). 2nd clutch destroyed @ 2 d. Only clutch destroyed @ 18 d. 1 egg or chick disappeared at or shortly after hatch. All chicks disappeared w/in 3 d of hatching. All eggs or chicks disappeared w/in 24 hrs of hatching. All chicks disappeared w/in 7 d of hatching. Hen disappeared; never observed again. Nest destroyed @ approx. 22 d (mammal), Apparently unsuccessful. Apparently unsuccessful. RCap-capture date, Rcp-recapture date, WtB-weight (g) before nesting, WtA-weight (g) after nesting, Chg=net weight (g) change, CIn-c1utch initiation date, Hch-hatch date, XHc-percent hatched, H1C-number of eggs in 1st clutch, H2C-number of eggs in 2nd clutch, XF1-percent fledged . .. �nest predations complete and of all brood failures brood losses occurred within chick mortality hatching. to chick mortality. inclement weather hens brooded their chicks than they did during good weather. albus) chicks contained Erikstad that drops in ambient air temperature with dense vegetation) reduced feeding critical densities of invertebrate during wet weather. time and avoiding proportions similar of nests depredated brood failures to those reported No measures due to stochastic events, probably reproductive of Giesen that were to be high compared by time budgeted to failure among hens, possibly related to period of day (quadratic any of the variation but they were not significant respectively; effects during this study. swamped any effects Only two covariates, and the date, explained foraging, of nests depredated of fitness were explained Near-total budgets. prey associated (1977). feeding by hens. foraging the dense in starvation. during this study appeared by Giesen they found areas with more prey at such a et al. (1980) reported However, during a warm The synergistic life stage easily could have resulted to proportions (1982) with rain reduced time of chicks by 601, and that chicks avoided (and the highest for longer (Lagopus lagopus In addition, coincident (1988) noted and Spids0 twice as much food (dry weight) dry summer than during a cold wet summer. vegetation all other 14 days of Schmidt found that crops of 0-27 day-old willow ptarmigan feeding All tended to be cold and rainy during peak of hatch, which may have contributed periods 7 days of hatching; (the 3 lost by hen 2) occurred within Weather that during remain undetermined. df - 1 for each covariate). (P among times spent 0.16 and P - 0.20, Less feeding occurred term) �314 during period 2 (mid morning to mid afternoon) than during periods 1 or 3, which agrees with Schmidt's (1988) observations that ptarmigan do most of their feeding early and late in the day. Hens spent a considerable amount of time (25 to 70 minutes, with 45 - 55 minutes being typical) meticulously covering their clutches with bits of vegetation after laying each egg. Between laying eggs, covering clutches, and walking or running to/from nest areas for each egglaying, hens budgeted considerable amounts of time to nesting activities prior to onset of incubation, accounting for the decline in time spent foraging as pre-incubation season progressed. Net weight changes of hens were not directly comparable because dates of recapture varied widely among hens in relation to their nesting schedules. Therefore, only pre-nesting weights of hens were regressed against time budgeted by hens to foraging; the variation in weights was not explained by foraging budgets. However, comparisons of pre-nesting weights and ages of hens using SE versus NY sites were considered later to be worth investigating. Mean pre-nesting weights of NY and SE hens differed (P - 0.01; df - 10), with NY hens weighing 410 ± 12.7 g and SE hens weighing 378 ± 21.8 g. However, GT hens were captured 6 days later than the other hens, and may have gained some weight in that time. hens, mean weight of NY hens was 403.3 ± 15.3 g. After dropping GT The weight difference was no longer statistically significant (P - 0.1232; df 7), although a tendency was still apparent, which may have important implications for hens returning to breed in subsequent years. At two different study areas, Robb et al. (1992) found that adult female willow ptarmigan that were heavier prior to nesting had significantly '. �greater rates of return in subsequent hens with lower body mass not true for yearling rates of return. breeding seasons than did adult (65% vs. 33% and 61% vs. 15%). hens, whose weight Robb et al. suggested for female willow ptarmigan differences The same was did not affect that the costs of reproduction may be cumulative over several breeding seasons, and that female willow ptarmigan survival as they age if they have greater body mass prior to nesting. Therefore, on the basis of weight rates of return for NY hens. yearlings (see below), reproductive weights weight have better However, because and hadn't undergone hens was 12 g lighter of NY yearling hens. age on Trail Ridge, and, ultimately, their survivorship in subsequent breeding could be affected. Mean age of hens at NY sites was 2.3 least 3 years), and rates of return records regions was significant 6.5), (and may have been a partial of hens at SE sites). may be an indirect indicator .. ± 1.0 years (which may be ages of 2 hens, although between the than May's show they were at and mean age of hens at SE sites was 1.2 The age difference weights (1975) study; that food is limiting their weights low due to unknown weight less than other hens of comparable it could be a good indicator seasons of the average than the average hens was 26 g heavier If SE hens weigh effects their lower However, hens at the same time of year in May's average weight yearling most SE hens were cumulative could affect their rates of return. of yearling of alone, one would expect greater cost, there would be a lag-time before of SE yearlings chances (P - factor influencing Age structure 0.0394; df pre-nesting of hens in a given area of food resources adult hens tend to return to previously-used ± 0.4 years. in that area. territories, Because and because �316 reproductive return failure in a prior breeding rates of adult hens generally (K. M. Giesen, should not dominate However, poor survivorship assessing territory quality in which case age structure to lower weights, for selecting inferior territories). reproductive been indicative observed distances (and subsequently settle effects habitat, towards to capture However, gross movements, moved by hens within periods. time spent foraging However, observed using a feeding instead, long- periods may have which could be more larger than those For example, their territories during several most gross ranged periods sample periods from 100-200 were generally hen 8 at SB was area at least 500 m away from her eventual nest site, yet I never captured Schmidt sampling during single observation 5-40 m. of stress samples were not on a spatial-scale I-hour sampling on would be affected. moved by hens during behavior during the 500 m movement during (1969) found that hens generally nests 46-91 m from feeding areas. Braun sampling. located their (1969) also measured daily of hens, with results being similar Interestingly, are and low rates skewed success would not have to differ; m, and those captured movements could become in resource-poor of food quantity In contrast, when food supplies If there were time-lagged by time spent foraging. inadequate at any location. poor survivorship, for both adults and recruits Distances explained territories with breeding term survival hens The same result would occur if hens use other criteria and/or pers. corom.), yearling (i.e., settle where of return), associated to affect could occur if hens make mistakes leading classes. is not known female age classes inadequate, younger season to those of Schmidt. hen 8 spent the least amount of time foraging and the �)1 feeding area hen 8 was travelling willow available to her. in a large drainage feeding; see Chapter wandering with inadequate farther If hens will settle on food supplies, distances too tall to use for then they could be expected to find food. Not only would hens in search of food spend more energy on locomotion, they would be exposed to a greater anecdotal, the movements inadequate food resources ptarmigan and was probably 1, this volume). to range over greater the nearest (Some willow was closer than that, but it occurred territories 500 m to use contained territory risk of predation. While of hen 8 may have been indicative at SB. Zablan of (1986) found evidence that sizes at SE sites were larger than they were in 1969 (Schmidt 1969). A final possibility impacted willow differences to consider throughout all Trail Ridge sites. in any behaviors would not have been expected. damage to willow was observed foraging on and adjacent 1989 and 1990. or fitness values As mentioned supported decline the original is supported predictions by data collected, densities (willow or otherwise) elk-inflicted by evidence densities hypotheses of ptarmigan resources, elk that elk use of ptarmigan (Melcher 1992). of this pilot study were not alternative on territories hens spring and summer, significantly On the basis of my results, may avoid settling earlier, at NY sites and that breeding in breeding supported. among ptarmigan to NY sites throughout at both SE and NY sites have declined While If true, then no at all sites, and I observed This possibility may be increasing is that elk have negatively the on Trail Ridge were I believe with obvious however, to explain that ptarmigan inadequacies hens of food they may not be able to make . I �318 perfect distinctions between marginally-suitable and moderatelysuitable territories. Therefore, some hens may select resource-poor habitat, undergo low gains in pre-nesting weight, and experience poor rates of return and/or survivorship. As a consequence, habitat with marginal food supplies should support low densities of ptarmigan and the population of hens should be dominated by younger age classes. 'LITERATURE CITED Altmann, J. 1974. Observational study of behavior: sampling methods. Behavior 49:227-365. Bailey, A. M., and R. J. Niedrach. 1965. Birds of Colorado. Vol. I. Denver Mus. Nat. Hist., Denver. 895 pp. Bear, G. D. 1989. Seasonal distribution and population characteristics of elk in Estes Valley, Colorado. Colo. Div. Wildl. Spec. Rep. 65. 14pp. Braun, C. E. 1969. Population dynamics, habitat, and movements of white-tailed ptarmigan in Colorado. Ph.D. Diss., Colorado State Univ., Fort Collins. 189pp. 1971. Habitat requirements of Colorado white-tailed ptarmigan. Proc. West. Assoc. State Game and Fish Comm. 51:284-292. _________ , and G. E. Rogers. 1971. White-tailed ptarmigan in Colorado. Colorado Div. Game, Fish and Parks Tech. Publ. 27. 80pp. _________ , R. K. Schmidt, Jr., and G. E. Rogers. 1973. Census of Colorado white-tailed ptarmigan with tape-recorded calls. J. Wildl. Manage. 7:90-93. _______ , R. W. Hoffman, and G. E. Rogers. 1976. Wintering areas and winter ecology of white-tailed ptarmigan in Colorado. Colorado Div. Wildl. Spec. Rep. 38. 38pp. _____ , and K. M. Giesen. 1990. Population dynamics of whitetailed ptarmigan, Job Progress Rep., Colorado Fed. Aid Project W-152-R. Apr. 1990. 264pp. _______ , D. R. Stevens, K. M. Giesen, and C. P. Melcher. 1991. Elk, white-tailed ptarmigan, and willow relationships: a management dilemma in Rocky Mountain National Park. Pages 74-85 in McCabe, R.E., (ed.). Trans. 56th N. Am. Wildl. and Nat. Res. Conf., Wild1. Manage. Institute. �Butler, D. C. 1979. Effects of a high-density population of ungulates on breeding bird communities in deciduous forest. M.S. Thesis, Colorado State Univ., Fort Collins. 67pp. Caraco, T. 1980. environment. On foraging time allocation Ecology 61:119-128. in a stochastic Choate, T. S. 1963. Habitat and population dynamics tailed ptarmigan in Montana. J. Wildl. Manage. 699. of white27:684- Erikstad, K. E., and T. K. Spids0. 1982. The influence of weather on food intake, insect prey selection and feeding behaviour in willow grouse chicks in northern Norway. Ornis Scand. 13:176-182. Giesen, K. M. 1977. Mortality and dispersal of juvenile whitetailed ptarmigan. M.S. Thesis, Colorado State Univ., Ft. Collins. 55pp. _____ , and C. E. Braun. 1979a. Nesting behavior ptarmigan in Colorado. Condor 81:215-217. _____ , and Colorado. _ 1979b. Renesting Condor 81:217-218. of white-tailed of white-tailed ptarmigan in _____ , and T. A. May. 1980. Reproduction and nest-site selection by white-tailed ptarmigan in Colorado. Wilson Bull. 92:188-199. .. Hobbs, N. T., D. L. Baker, J. E. Ellis, D. M. Swift, and R. A. Green. 1982. Energy and nitrogen-based estimates of elk winter-range carrying capacity. J. Wildl. Manage. 46:12-21. Holling, C. S. predation 398. 1959. Some characteristics of simple types of and parasitism. Canadian Entomologist 91:385- Jackson, S. 1991. Changes to bird communities wild ungulates. Proc. Ecol. Soc. Am. from grazing by Knopf, F. L., J. A. Sedgewick, and R. W. Cannon. 1988. Guild structure of a riparian avifauna relative to seasonal cattle grazing. J. Wildl. Manage. 52:280-290. Marr, J. W. 1967. Ecosystems of the east slope of the Front Range Colorado. Univ. Colorado Ser. BioI. 8. 134pp. May, T. A. 1975. Physiological ecology of white-tailed ptarmigan Colorado. Ph.D. Diss., Univ. Colorado, Boulder. 311pp. _____ , and C. E. Braun. 1972. Seasonal foods of adult white-tailed ptarmigan in Colorado. J. Wildl. Manage. 36:1180-1186. in in �320 Moss, R., and A. Watson. 1984. Maternal nutrition, egg quality, and breeding success of Scottish ptarmigan Lagopus mutus. Ibis 126:212-220. Myrberget, S. 1987. The effects of sheep grazing on a willow grouse breeding habitat. Fauna 40:144-149. National Park Service. 1975. Resource management plan: Rocky Mountain National Park and Shadow Mountain National Recreation Area. U.S. Dept. Inter., Natl. Park Serv., Estes Park, CO. 88pp. National Park Service. 1988. Statement for management. U.S. Dep. Inter. Natl. Park Servo NPS D-23d. Washington, D.C. 60pp. Olmsted, C. E. 1979. The ecology of aspen with reference to utilization by large herbivores in Rocky Mountain National Park. Pages 87-89 in M.S. Boyce, and L.D. Hayden-Wing, (eds.). North American elk: ecology, behavior, and management. Univ. Wyoming, Laramie. Parker, H. 1981. Renesting biology of Norwegian willow ptarmigan. J. Wildl. Manage. 45:858-864. Robb, L. A., K. Martin, and S. J. Hannon. 1992. Spring body condition, fecundity, and survival in female willow ptarmigan. J. Anim. Ecol. 61. (In Press). Ryder, R. A. 1980. Effects of grazing on bird habitats. Pages 51-64 in Management of western forests and grasslands for non-game birds. U.S. Dep. Agric., For. Servo Gen. Tech. Rep. INT-86. SAS Institute, Inc .. 1988. SAS/STATe Procedures guide: release 6.03 edition. Cary, NC. 1029pp. Schmidt, R. K., Jr. 1969. Behavior of white-tailed ptarmigan in Colorado. M.S. Thesis, Colorado State Univ., Fort Collins. 174pp. 1988. Behavior of white-tailed ptarmigan. Pages 270Adaptive strategies and population ecology of northern grouse. Minnesota Press, Minneapolis. 299 in Bergerud, A.T., and M.W. Gratson, (eds.). Stevens, D. R. 1980a. The deer and elk of Rocky Mountain National Park: a ten-year study. U.S. Dep. Inter., Natl. Park Servo Rep. ROMO-N-13, Estes Park, CO. 163pp. 1980b. Effect of elk on alpine tundra in Rocky Mountain National Park. Pages 228-241 in C.L. Jackson and M.N. Schuster, (eds.). Proc. High Altitude Revegetation Workshop 4. Colorado State Univ. Infor. Series 42. �)LI Taylor, D. M. 1986. Effects of cattle grazing on passerine birds nesting in riparian habitat. J. Range Manage. 39:254-258. Thomas, V. G., and R. Popko. 1980. Fat and protein reserves of wintering and prebredding rock ptarmigan from south Hudson Bay. Can. J. Zool. 59:1205-1211. Tucker, T. L. 1987. Cattle grazing affects nongame wildlife populations and fish habitat in a montane riparian area. M.S. Thesis, Colorado State Univ., Fort Collins. 84pp. Watson, A., and P. J. O'Hare. 1979. Red grouse populations on experimentally treated and untreated Irish bog. J. Appl. Ecol. 16:433-542. Weathers, W. A., and K. A. Sullivan. 1989. Juvenile foraging proficiency, parental effort, and avian reproductive success. Ecol. Monogr. 59:223-246. Weber, W. A. 1976. Rocky Mountain flora. Univ. Press, Boulder. 479pp. Colorado Assoc. West, G. C. 1968.· Bioenergetics of captive willow ptarmigan under natural conditions. Ecology 49:1035-1045. Zablan, M. A. 1968. Breeding territory size of white-tailed ptarmigan in Rocky Mountain National Park, Colorado. Colorado Div. Wildl. unpubl. rpt., Fort Collins. l5pp. Zwickel, F. C. 1972. Some effects of grazing on blue grouse during summer. J. Wi1dl. Manage. 36:631-634. Prepared by Coa\~ ( Approved 0- ~. \~\ Cynthia P. Melcher by Clait E. Braun Wildlife Research Leader •• .v.. ��)L) JOB PROGRESS REPORT State of: Colorado Project: W-167 -R Upland Bird Research I Work Plan: 22 Job Title: Upland Bird Research Publications Period Covered: Author: Job 01 January through 31 December 1991 Clait E. Braun Personnel: Clait E. Braun, K. M. Giesen, R. W. Hoffman, T. E. Remington, and W. D. Snyder, Colorado Division of Wildlife ABSTRACT The following articles were published in 1991: Benson, L. A., C. E. Braun, and W. C. Leininger. 1991. Sage grouse response to burning in the big sagebrush type. Proc. Issues and Technology in the Management of Impacted Western Wildlife. Thorne Ecol. Inst. 5:97-104. Braun, C. E. 1991. Distribution and status of sage grouse in Colorado. Trans. West. States Sage and Columbian Sharp-tailed Grouse Workshop. 17:12 (Abstract). _____ , D. R. Stevens, K. M. Giesen, and C. P. Melcher. 1991. Elk, whitetailed ptarmigan and willow relationships: a management dilemma in Rocky Mountain National Park. Trans. North Am. Wildl. and Nat. Resour. Conf. 56:74-85. George, J. L., C. E. Braun, R. A. Ryder, and E. Decker. 1991. Response of waterbirds ~o experimental disturbances. Proc. Issues and Technology in the Management of Impacted Western'Wild1ife. Thorne Eco1. Inst. 5:52-59. Giesen, K. M. _____ 1991. Broadcasting birds. Colorado Outdoors 40(3):28-29. 1991. Movements and nest site selection by lesser prairie-chicken hens in Colorado. Proc. Prairie Grouse Tech. Council 19:14 (Abstract). _____ , and C. E. Braun. 1991. Demography of white-tailed ptarmigan in Rocky Mountain National Park, Colorado. Central Mtns. and Plains Sect., The Wild1. Soc. 36:Abstract. Hupp, J. W., and C. E. Braun. 1991. Geographic variation among sage grouse in Colorado. Wilson Bull. 103:255-261. Olson, T. E., C. E. Braun, and R. A. Ryder. 1991. Agricultural land use and mourning doves in eastern Colorado: implications fbr nesting and production in the Great Plains. Prairie Nat. 23:1-10. : �324 Remington, T. E. 1991. Non-target effects of aerial spraying to control Russian wheat aphids. Central Mtns. and Plains Sect., The Wildl. Soc. 36:Abstract. _____ , and C. E. Braun. 1991. How surface coal m1n1ng affects sage grouse, North Park, Colorado. ·Proc. Issues and Technology in the Management of Impacted Western Wildlife. Thorne Ecol. Inst. 5:128-132. _____ , and W. D. Snyder. 1991. Conservation Reserve Program - panacea or ecological trap? Central Mtns. and Plains Sect., The Wi1dl. Soc. 36:Abstract. _____ , and W. D. Snyder. 1991. Outdoors 40(6):11-13. Past and present pheasants. Colorado Schmutz, J. A., and R. W. Hoffman. 1991. Variable first prebasic molt in Rio Grande and Merriam's wild turkeys. Wilson Bull. 103:295-300. Schroeder, M. A. 1991. Movement and 1ek visitation by female greater prairie-chickens in relation to predictions of Bradbury's female preference hypothesis of 1ek evolution. Auk 108:896-903. _____ , and C. E. Braun. 1991. Walk-in traps for capturing greater prairiechickens on leks. J. Field Ornitho1. 62:378-385. Snyder, W. D. 1991. Wheat stubble as nesting cover for ring-necked pheasants in northeastern Colorado. Wildl. Soc. Bull. 19:469-474. _____ , and G. C. Miller, 1991. Changes in plains cottonwoods along the Arkansas and South Platte rivers - Eastern Colorado. Prairie Nat. 23:165-176. Prepared by _tla __v_'_z._.-I.~:"="'_ __;;___ Clait E. Braun Wildlife Research Leader ~ �)L7> JOB FINAL REPORT State of: Project: Colorado Upland Bird Research 'W-152/l67-R 'Work Plan: 25 Job Title: Evaluation of 'Wildlife Responses to Pesticides Used in 'Wheat Farming Period Covered: : Job _1_ 01 January 1989 through 31 December 1991 Author: Thomas E. Remington Personnel: Clait E. Braun, Carol A. Mehaffy, Michael 'W.Miller, Bradley J. Parks, Thomas E. Remington, Joan D. Ritchie, Lyn Stevens, David A. 'Wilson, Colorado Division of 'Wildlife; James Echols, Wendy Meyer, Frank Peairs, Stan Pilcher, Colorado State University; John Pearson, Claude Ross, Ted Warfield, FMC Corporation .. ABSTRACT The impacts of two methods using pesticides to control insect pests in winter wheat on bird communities were investigated. These were aerial spraying of Lorsban (ch1orpyrifos) or Di-Syston (disulfoton) to control Russian wheat ", aphids (Diuraphis noxia) in spring and microtubule injection of Furadan (carbofuran) at planting to control grasshoppers. No dead or impaired birds were found during searches of 178 ha within 11 wheat fields sprayed with either Lorsban (113 ha) or Di-Syston (65 ha). Searchers located 61% of carcasses placed in fields to evaluate search efficiency. Fifteen active nests (or broods) of several bird species were found within sprayed fields and were not obviously affected. Spraying of Di-Syston, but not Lorsban, slightly decreased (l < 0.05) 48-hour survival of pheasant chicks in a controlled experiment. 'When this experiment was repeated, spraying of Di-Syston or Lorsban had no impact on.24 or 48~hour survival of pheasant chicks .. Spraying of Di-Sy!;ton or Lorsban to control Russian wheat aphids in spring does riot appear to impact birds significantly. Carcasses of·4 horned larks (Eremophila alpestris) and 1 meadowlark (Sturnella neglecta) were found dead during searches of 65 km around the perimeters of 21 fields, 7-10 and 14-21 days; after seed planting and microtube injection of Furadan. Two birds were apparently killed by collision with a vehicle or gunshot, causes of death for the other carcasses could not be ascertained. Carbamate residues in grasshoppers averaged 1.31 mgfkg, a level unlikely to cause avian mortality. Canada geese (Branta canadensis) largely rejected Furadan-treated wheat in a controlled experiment. An average of 34 g of wheat remained per 0.785-m2 . sampling plot in the treatment pen vs. 2 grams in the untreated pen. Brain cholinesterase activity of Canada geese exposed to Furadan-treated wheat was unaffected (f> 0.05), although plasma cholinesterase activity was depressed about 38%. ��327 EVALUATION OF WILDLIFE RESPONSES TO PESTICIDES USED IN WHEAT FARMING Thomas E. Remington INTRODUCTION Wheat is the predominant cultivated crop in Colorado with upwards of 3 million acres (1.2 million hectares) planted each year. Wheat fields are used extensively for foraging and or breeding by a diverse assemblage of wildlife including ring-necked pheasant (Phasianus colchicus), horned larks, lark buntings (Calamospiza melanocorys), mourning doves (Zenaida macroura), Canada geese, and pronghorn (Antilocapra americana). Russian wheat aphids have caused extensive damage to wheat in Colorado since arriving in 1985. Consequently, massive aerial spraying has been conducted to control aphids; as much as 45% of planted wheat has been treated annually. Aerial applications of Di-Syston or Lorsban (chlorpyrifos) have emerged as the predominant treatment methods. Both are highly toxic organophosphate pesticides with the potential for wildlife mortality (Smith 1987). Microtubule injection of Furadan is a relatively new technique for controlling grasshopper depredation on immature winter wheat in fall. This technique has also been shown to be effective in controlling aphids in wheat (Guerra-Sobrevilla 1988). Microtubule injection has several advantages (from a wildlife perspective) compared to more conventional methods of pesticide application. The pesticide is applied only as a narrow border treatment (typically 12-14 rows) and is injected as a liquid 5 cm deep in the soil around the seed; consequently wildlife exposure is minimized. Furadan is a systemic insecticide which is highly toxic to wildlife (Flickinger et al. 1980, James 1987, Smith 1987, Littrell 1988). Previous bioassays of immature winter wheat treated by microtubule injection of Furadan have shown significant insecticidal activity into April. While this has positive benefits for control of grasshoppers and/or aphids, it suggests that Furadan residues or metabolites persist overwinter and indicates a potential for significant wildlife exposure. Wildlife potentially at risk of significant exposure to this pesticide would be those that feed directly on exposed seeds or immature wheat, or on grasshoppers (or other insects) that feed on wheat. Horned larks and western meadowlarks feed on exposed wheat seeds. Pronghorn and Canada geese feed on winter wheat extensively from late fall until early spring. Several insectivorous birds, primarily eastern and western kingbirds (Tyrannus tyrannus and I. verticalis), American kestrels (Falco sparverius), burrowing owls (Speotyto cunicularia), and loggerhead shrikes (Lanius ludovicianus), could be expected to feed on contaminated grasshoppers and may be at some risk. Risks may be mitigated for some species by timing of fall migrations. However Swainson's hawks (Buteo swainsoni) assemble in large pre-migratory and migratory aggregations within farmland and rangeland of eastern Colorado and feed extensively, if not exclusively, on grasshoppers (Bailey and Niedrach 1965, Woffinden 1986, Johnson et al. 1987). The purpose of this study was to evaluate the impacts of aerial spraying to control aphids and of microtubule injection of Furadan to control grasshoppers '. �328 or aphids on avian wildlife. Emphasis was on ascertaining direct mortality but indirect effects such as cholinesterase depression were also investigated. P. N. OBJECTIVES 1. Determine acute mortality of wildlife 1-3 days post-spray resulting from prescribed levels of Di-Syston or ch10rpyrifos. 2. Recover carcasses of wildlife suspected of dying from pesticide poisoning for analysis of cause of death and pesticide residue levels. 3. Monitor impacts of spraying prescribed levels of Di-Syston or ch10rpyrifos on avian nesting success. 4. Determine level of brain cholinesterase depression in songbirds and pheasants 24-48 hours post-spray as an index to both pesticide exposure and potential effects. 5. Measure toxicity of prescribed levels of Di-Syston and chlorpyrifos to 7-10 day-old pheasant chicks. METHODS Wheat Aphid Study Three research approaches were used. Transects were conducted to search for dead or impaired wildlife in sprayed fields. Exposure of breeding birds to pesticides (potentially causing sublethal effects on behavior) was evaluated by collecting horned larks from sprayed and unsprayed fields and measuring • brain acetylcholinesterase activity. Acute toxicity and indirect effects of these pesticides on survival of pheasant chicks was evaluated by 2 experiments, 1 each in spring of 1989 and 1990. Specific methodology for each approach follows. Transects were conducted by 4-5 people walking abreast, about 20 rows apart 13 days post-spray until 8.1 ha had been searched per field. Most searches were conducted with the rows, although it was found that as wheat grew taller visibility of carcasses was greatest walking against the rows. Search efficiency was measured as the percent recovery of house sparrows (Passer domesticus) placed in sprayed fields prior to the search. A randomized complete block design was used in the pheasant chick experiment conducted in 1989 (Fig 1). Nine strips, 121.9 m wide and 381 m long, were marked with flagging and randomly assigned to 1 of 3 treatments; Di-Syston, Lorsban, or unsprayed control. Within each strip, 3 of 36 possible 0.1 ha (1/4-ac) pen locations were randomly selected. Pens were constructed of 61 by 2.54 cm (24" by 1") mesh poultry netting supported by rebar and aluminum rods. Pens were offset 13 m from either edge of the strip to prevent or minimize drift of pesticide across treatments. Within the center of each pen a 9.75 m2 circular pen was constructed of 1.22 m (48") hardware cloth. Ten, 6-day old pheasant chicks were placed in each pen from 0830 to 0950. Di-Syston and Lorsban strips were sprayed with 1.12 kg active ingredient (a.i.) per ha or 0.84 kg a.i./ha, respectively. Two Pawnee PA 25 airplanes calibrated to apply �329 treatments in 3.1 liters of spray volume per ha (2 gallons/acre) were used. Spraying began at 1030 and was completed by 1200 hours. Conditions were ideal for spraying; sunny, warm and little or no breeze. 122 m SPRAY STRIPS '. Fig. 1. Experimental design and layout of treatment assess toxicity of Lorsban and Di-Syston to pheasant 1990 (bottom). strips and pens used to chicks in 1989 (top) and �330 To facilitate recovery and prevent escape, chicks were initially placed in the small pens. Chicks were removed at the end of each day and kept indoors at 32.1 C (90 F) and provided pelleted chick feed and water. Thirty (of the original 90) chicks from each treatment were individually marked by wrapping a numbered strip of scotch tape around 1 leg. These chicks were weighed each morning and returned to the larger pens for 7 days to evaluate the suitability of sprayed areas as brood habitat. Remaining chicks were labelled with nail polish which identified the treatment to which they were exposed and kept indoors to monitor subsequent mortality (2 legs painted - Lorsban; 1 leg painted - Di-Syston; neither painted - control). A randomized complete block design was also used in the 1990 pheasant chick experiment (Fig. 1). Twelve strips, 244 m long by 55 m wide, were marked with flagging within a 24-ha wheat field about 3 km south and 3 km east of Akron, Colorado. A 27-m buffer strip was marked between strips to prevent drift of pesticide across treatments. Treatments, Di-Syston, Lorsban, or unsprayed control, were randomly assigned to 1 of 3 strips within each of 4 blocks. Within each strip, 2 of 16 possible 0.1 ha (1/4 acre) pen locations were randomly selected. Pens were constructed as in 1989. Within the center of each pen a 9.75-ml circular pen was constructed of 1.22 m (48") hardware cloth. Hot boxes were constructed of 46 or 51 cm (18 or 20") diameter galvanized duct pipe, covered with fiberglass insulation and clear plastic and placed in each circular hardware-cloth pen. Temperature within each hot box was maintained at 32 C (90 F) by 125-watt heat lamps (suspended at the top) controlled by line voltage thermostats. Three generators furnished electricity to heat lamps. A door was cut into the bottom of each hot box to allow chicks access. Ten, 6-day old pheasant chicks were placed in each pen from 0645 to 0730 hours. Di-Syston and Lorsban strips were sprayed on 22 May using equipment and procedures described for the 1989 experiment. Spraying " began at 0740 and was completed by 0830 hours. Conditions were ideal for spraying; sunny, warm and little or no breeze. To facilitate recovery and prevent escape, pheasant chicks were initially placed in the small pens. Chicks were placed within the hot boxes near sunset each day and during inclement weather periods. They were provided pelleted chick feed and water ad libitum. Chicks were released from the hot boxes each morning around 1000 when air temperature had warmed. Carbofuran Study The purpose of this research was to gather preliminary information on mortality or morbidity of wildlife thought to be at risk from microtubule injection of Furadan as an at-planting treatment to control grasshoppers. Effects on passerine birds were evaluated by searching borders of treated fields (Furadan 4F at a rate of 14.8 ml per 305 linear m) for dead or impaired birds at about 1 and 2 weeks after planting. Searcher efficiency was estimated as recovery of house sparrow carcasses placed within field margins prior to the search. The effect on Canada geese of exposure to furadan-treated wheat was evaluated in two experiments in 1989 and 1990 using slightly different approaches and methods. In 1989 12 wild geese were captured on corn bait piles using a cannon net, and immediately transported to, and placed within, 1 of 3 welded wire enclosures (4 in each). Enclosures consisted of either 6 rows of treated �331 wheat, 6 rows of treated and 6 rows untreated wheat, or 6 rows of untreated wheat (check). These enclosures were within 12, 305-m long strips of 6 rows of wheat each planted on 19-20 August in a field near Briggsdale. Furadan 4F was applied to alternate strips by microtubule injection at a rate of 14.8 ml per 305 linear m. The birds were left within the pens for a day and a half to feed. They were then killed by CO2 asphyxiation. Heads were removed, placed on dry ice, then transported to and stored within a freezer at -60 C. Brain acetylcholinesterase activity was determined following Hill and Fleming (1982). The 1989 experiment was hampered by extremely low residues of Furadan in the treated wheat to which geese were exposed, either because of poor uptake, metabolism, or possibly erroneous measurement of Furadan residues by the contract laboratory. The experiment was repeated in 1990 with a modified design to insure high residue levels, representative of a worst case scenario. We planted wheat into sub-irrigated ground and exposed the geese 25-26 days after planting rather than 98-99 days as in 1989. Agri Pro, Inc., provided an irrigated field at their research farm about 4 km southwest of Berthoud, Colorado. Winter wheat (Sandy variety) was planted on 17 September 1990, at a rate of 16.2 kg per ha with a 0.3 m (12-inch) row spacing. Furadan 4F (14.8 ml per 305 linear m) and liquid fertilizer (7.68 kg N, 26.1 kg P20S per ha) were applied in-furrow by micro-tubule injection. Two blocks of untreated wheat were planted similarly, although without Furadan injection (Fig. 2). Canada geese (29) were captured while flightless on 4 June from the Loveland Golf course and maintained at the Foothills Wildlife Research Facility until the feeding trial. Birds were fed a commercial pelleted chow (Purina Turkey Ration), although they supplemented this by feeding on grass and weeds within their pen. Geese were wing clipped in late July to minimize injuries within the pen and to prevent escape from the welded wire pens in the wheat field. Geese were transported to the site on 10 October and released into a 47.2 m by 14.6 m (48 row) welded wire enclosure around untreated wheat. Geese were allowed to feed within "this enclosure for 2 days to acclimate them to a wheat diet and to conditions at the site. They were then moved into 1 of 2 adjacent 47.2 m x 7.3 m (24 row) enclosures containing either Furadan treated (15 geese) or untreated wheat (14 geese). The birds were left within the pens for two days to feed. They were then killed by CO2 asphyxiation. Heads were removed, placed on dry ice, then transported to, and stored within, a freezer at -60 C. Brain and plasma acetylcholinesterase activity was determined following Hill and Fleming (1982). All remaining wheat above ground level was clipped and weighed from 10, 0.785-m2 circular plots randomly located within treated and untreated enclosures to measure feeding intensity. Two 100 g samples of treated and untreated wheat were collected from outside the enclosures on the first trial day, kept frozen, and sent to A&L Mid West Laboratories for analysis of Furadan and Furadan metabolite residues. Analysis was by HPLC with a ultra-violet detector (no other details available) with a detection limit of 0.1 ppm. Because of questions about the accuracy of the residue levels found by A&L, duplicate samples were sent to the ACG Developmental Chemistry Department laboratory of FMC Corporation in Princeton, New Jersey for additional analysis. ~ �332 61 m (/) co v Fig. 2. m FURADAN TREATED ~ o a: 61 UNTREATED UNTREATED Field design of Furadan-wheat Canada goose study. RESULTS and DISCUSSION Russian Wheat Aphid Study Mortality Transects.--Portions of 11 fields, 178 ha total, (65 ha treated with Di-Syston, 113 ha treated with Lorsban) were searched and no dead or impaired wildlife were found. Fields were searched 3 hours (1), 1 day (7), 2 days (1), or 3 days post-spray (2). Horned larks, lark buntings, meadowlarks, and mourning doves were commonly observed in sprayed fields and appeared to act normally. Nests with eggs or chicks and/or fledged baby birds were found in some sprayed fields, usually when the attending parent(s) flushed. We located 7 horned lark nests (2 with eggs, 2 with chicks) or fledged broods (3 broods of 1-3 chicks), 5 lark bunting nests (5 with eggs), and 3 mourning dove nests (2 with eggs, 1 with young). At least in these instances, spraying did not impair normal reproductive behavior such as incubation and feeding young, nor did it kill dependant young in nests. This was confirmed by follow up visits to most nests located within a day of spraying. We recovered 61% (17 of 28) of carcasses placed in fields prior to searches. Carcasses were removed from wheat fields slowly by scavengers (Fig. 3); 75% were still present and visible 3 days after placement and 50% were present after 6 days. These data suggest that if significant mortality had occurred as a result of spraying we would have detected it. Spraying of Di-Syston apparently resulted in the deaths of 9 black-tailed jack rabbits (Lepus californicus) about 19 kilometers southwest of Pritchett in Southeast Colorado. The dead jackrabbits were found in a shortgrass pasture on 10 May, 1990, 1-30 m from a wheat field which had been sprayed late the day before. No dead jackrabbits were found within the wheat field. Another jackrabbit die-off was reported following spraying of Di-Syston north of Eaton, but we were unable to locate any carcasses. Jackrabbits are extremely sensitive to a metabolite of Di-Syston produced when the parent compound is " �333 metabolized by growing vegetation. A likely scenario would be that vegetation in the pasture was contaminated with Di-Syston by overspray or drift. Jackrabbits feeding on vegetation within the pasture would be exposed to a large dose of the metabolite of Di-Syston because the spray would be concentrated on the relatively short vegetation in the pasture. Jackrabbits have been observed within wheat fields sprayed with Di-Syston and were apparently unaffected. They appeared to be using maturing wheat fields for cover while foraging in nearby pastures. Jackrabbits are probably not at significant risk if spraying is confined to wheat. 18 18 en w en en c:( o a: 14 12 c:( o Z 10 I eoL_--~~-----L2----~3------~4----~5~----~8------:7 DAYS Fig. 3. spring. Removal rate of house sparrow carcasses placed in wheat fields in Exposure of Breeding Birds.--Horned larks were collected from a field 2 days after Di-Syston spraying (5), from another field 1 day after Lorsban had been sprayed (5), and from a rangeland area about 20 km away (3 to serve as controls). Cholinesterase activity appeared depressed in horned larks collected from the field sprayed with Di-Syston relative to those collected from the field sprayed with Lorsban or the unsprayed controls (~± S.E. - 5.0 ± 0.5, 8.2 ± 0.8, and 6.7 ± 1.0 ~moles/min/g of brain tissue, respectively). Sample sizes are too small to make definitive conclusions, but results do suggest 20-30% depression in acetylcholinesterase activity, indicative of exposure to Di-Syston. The lack of detection of carcasses or moribund birds during mortality transects suggests this exposure was sublethal and effects relatively short term. Enzyme activity rates measured were only about 50% of levels found in horned lark brain tissue by McEwen et al. (1986). This may have been due to the prolonged (4-5 months) time carcasses were frozen. McEwen et al. (1986) found that aerial spraying of Lorsban on winter wheat at 0.56 and 1.12 kg a.i.jha to control cutworms resulted in significant depression of horned lark cholinesterase activity at 3 and 9 days post-spray. There was some evidence of suppression I day after spraying with Lorsban in this study, although sample sizes were small. '. �334 Pheasant Chick Mortality.--In the 1989 experiment, Di-Syston spraying lowered (f < 0.05) 48-hour, but not 24-hour survival of pheasant chicks (Fig. 4). An average of 7.3, 8.2, and 8.2 (of 10) chicks survived 48 hours per pen sprayed with Di-Syston, Lorsban or unsprayed, respectively. Subsequent survival was similar among treatment groups. 24-HOUR MORTALITY 10~----------------------------, SUBSEQUENT SURVIVAL 30~------------------------~ 28 8 --.--.-.---.-.-.----.--. ... --..... - ... -- .... --- 26 ---------~-.""..."...----. .... ..... . ' .. .;.~ ...• •• ~ (.) 61-------- 24~----------------------~' :c (.) u, o =It::41----r-----4 ~ CHECK LORSBAN DISYSTON 18 (.) 2 W _.-:r:(.) .. 16 - 14U---~---~--~--__U 1 2 3 4 5 DAYS SINCE SPRAYING Fig. 4. Survival of pheasant chicks 1-5 days following spraying with Lorsban (0.84 kg a.i./ha) or Di-Syston (1.12 kg a.i./ha). Chick weight dynamics were similar across all treatments (Fig. 5). Birds generally lost weight when kept outside. This suggests that wheat fields are poor brood habitat for chicks of this age, at least in the absence of a hen. In the 1990 experiment, spraying of Di-Syston or Lorsban did not decrease (f > 0.05) 24 or 48-hour survival of pheasant chicks relative to controls. An average of 9.7, 9.7, and 9.9 (of 10) chicks survived for 24 hours post-spray in pens exposed to Di-Syston, Lorsban, or unsprayed, respectively. Survival to 48-hours post-spray for these groups was 9.4, 9.1, and 9.5 chicks per pen, respectively. Survival of chicks was markedly improved from the experiment conducted in 1989. This was attributed to use of the hot boxes which allowed maintainenance of chicks at or near their preferred temperature and eliminated the need to capture chicks and transport them indoors. Di-Syston �335 significantly reduced survival of chicks in the previous experiment but had no effect in this experiment. In the 1989 experiment, a storm cell passing to the south late the afternoon of the day of spraying lowered temperatures dramatically and may have exasperated toxicity of Di-Syston. Cold stress can make birds more susceptible to carbamate pesticides (Rattner et al. 1982). Given that Di-Syston and Lorsban have similar avian toxicities (Smith 1987), it is puzzling that chick mortality differed in 1989. This may be due to lower application rates of Lorsban (0.84 kg a.i./ha versus·l.12 kg a.i./ha) or to higher rates of Di-Syston reaching ground (chick) level (F. Peairs, pers. commun.), or perhaps to differential effects of cold stress. 40 - -35 0> - CONTROL ---- DI-SYSTON LORSBAN r-ill o 1- L_ r~ ::> , 25 20 -~ 1 ---- ,~--- r- o --"r!./ /' J ,/ "'. ill Cl en ~ r- ::>::> 0 =«:..... / 3 4 5 ill Cl r- ~ 2 -, -,'., " " ~ ..--_"'_._'..".- en - _--- I: - 6 0 7 8 DAYS SINCE SPRAYING Fig. 5. Yeight dynamics of pheasant chicks sprayed with Lorsban (0.84 kg a.i./ha.) or Di-Syston (1.12 kg a.i./ha). In 1990, a male lark bunting was found apparently sick and unable to fly about 7 hours after spraying near strip 12 which had been sprayed with Lorsban. This bird was placed inside one of the pens and apparently recovered as it was not found later. It may have been exposed to Di-Syston or Lorsban. Two mallard (Anas platyrhynchos) nests were discovered in the wheat field while we were building pens. These hens were each incubating 10 eggs and both were in strips sprayed, one with Lorsban and one with Di-Syston. Both hens continued to incubate their clutches for at least a week post-spray. Data from the mortality transects and pheasant chick experiments indicate that significant avian mortality is unlikely when labelled rates of these two pesticides are sprayed to control aphids. Pheasant chicks younger than 5-6 days of age may be more susceptible to these pesticides. However, most spraying occurs before most pheasant eggs have hatched, particularly nests in green wheat. Spraying usually occurs early in the morning before temperatures have warmed and winds begin to increase. Chicks younger than 5-6 days are probably brooded by hens at this time and not directly exposed to pesticides. '. �336 Carbofuran Study Mortality Transects.--Sixty-five kilometers around the perimeters of 21 fields were searched for dead or moribund birds in 1989 and 1990 within 7-10 days of planting, and again 2-3 weeks after planting (12 fields). In 1989 two horned larks and 1 meadowlark were found dead, while 2 dead horned larks were found in 1990. None of these carcasses were fresh enough for measurement of acetylcholinesterase activity. The meadowlark had injuries consistent with death resulting from shotgun pellets (radius and ulna of right wing broken, hole in right thigh and right side of pelvis broken). One horned lark carcass found adjacent to a road had injuries consistent with being struck by an automobile. The other carcasses were too degraded to yield useful information as to cause of death, and may have been predated. One horned lark had 3 wheat seeds within it's stomach. Consumption of treated seeds is a possible route of exposure. Searcher efficiency averaged 69% (25 of 36 carcasses recovered). Efficiency within each field was 67, 75, 63, 87, and 60%. These results indicate that had significant mortality occurred, we would have detected it, assuming carcasses remained until our searches. This assumption was not tested directly in the fall. Fifty percent of house sparrow carcasses placed in wheat fields in eastern Colorado during spring were still present after 7 days (Fig. 3). It appears that mortality of passerines is negligible under this application method of furadan to the borders of fields. These results should be interpreted cautiously. An inherent weakness in this approach is that birds could feed within treated field margins, flyaway to die elsewhere, and go undetected during our searches. This could be a problem with horned larks that have large home ranges in fall and winter. Swainson's hawks were plentiful in and around treated fields during the period we conducted mortality transects. Examination of hawk scats indicated almost complete feeding on insects, predominately grasshoppers. We did not detect any dead, moribund, or abnormally behaving Swainson's hawks. Exposure of other insectivorous birds to furadan-contaminated grasshoppers was presumably minimal since few insectivorous birds were observed during our searches. Fall migrations may mitigate potential exposure of these birds to furadan, although the extent to which this occurs may vary annually. Furadan residues of composite grasshopper samples measured by A&L laboratories were below detection limits from 1 treated field and up to 30 times levels measured in 1989 from another. Residues measured by FMC Corporation's lab were repeatable, much less variable (Table 1), and verified by spiking check samples. Thus, residues measured by FMC were used for hazard assessments. Assuming a 50 g (0.05 kg) bird, a grasshopper weight of 0.89 g (0.00089 kg), and total carbamate residues of 1.31 ppm (from Table 1), ingestion of a single grasshopper represented about 5.6% of the LD50 for red-winged blackbirds (Agelaius phoeniceus) and about 1.9% of the LD50 for house sparrows. Swainson's hawks may eat 100 grasshoppers per day (Johnson et al. 1987). Assuming an intake of 100 grasshoppers with an average carbamate residue of 1.31 ppm, and a bird weight of 0.908 kg, Swainson's hawks would be exposed to 3.2% of an LD50. These hazard assessments suggest little avian risk from consuming grasshoppers killed or injured by Furadan, and support the lack of insectivorous bird carcasses recovered during mortality transects. �337 Table 1. Furadan and Furadan metabolite residue levels (ppm) in winter wheat from a Canada goose study treatment field (treated with an at-planting microtubule injection of Furadan of 14.8 m1/305 m) and in grasshopper samples collected (dead or dying) from similarly treated fields (percent recovery of spiked samples from each matrix indicated in parentheses). Sample Carbofuran Wheat 102 103 2.86 (94.2) 2.48 ND8 (95.7) ND 2.62 (94.2) 3.25 0.16 (87.5) 0.35 0.01 (89.0) 0.03 0.71 (85.1) 0.73 Grasshoppers 927 919 3-Keto Carbofuran 3-Hydroxy Carbofuran 8Not detected. Analysis of scats found at several treated fields indicated that striped skunks (Mephitis mephitis) were feeding extensively on grasshoppers along field margins. It is difficult to assess the potential impact to skunks of this exposure since information on how many grasshoppers they consume in a day and their sensitivity to furadan is not available. LD50's of dogs and rats are 19 and 11 mg/kg, respectively (Smith 1987). Using 10 mg/kg as an LD50,. and assuming a body weight of 3 kg and consumption of 100 or 500 grasshoppers per night, skunks would be exposed to 0.39 - 1.94% of an LD50. If these residues are accurate, and these assumptions reasonable, mortality of skunks seems unlikely. Canada Goose Experiment.-- In the 1989 experiment, brain acetylcholinesterase activity was unaffected by exposure to furadan treated wheat (Table 2). Two wheat samples collected at the Briggsdale site prior to this study had furadan residues of 0.06 ppm. Residues at the Loveland site were 0.84 and 1.16 ppm while treated wheat at the Severance site had residues of 0.34 and < 0.05 ppm. Variation among sites seems large since all 3 were planted at the same time, using the same equipment and applicator. It is not surprising that no effect was observed in geese at the Briggsdale site given these residues. In retrospect the Loveland site may have been a better test. It's possible that furadan at the Briggsdale site had been metabolized in the soil or wheat and was still present as a toxic metabolite. •• �338 Table 2. Brain acetylcholinesterase activity of 12 Canada geese after feeding in pens containing untreated, 50% furadan treated or 100% furadan treated wheat. Treatment Mean ± S.D. Untreated 50% Treated 100% Treated 1502 967 1007 959 867 751 1296 975 1072 1256 881 964 1108 ± 263 972 ± 234 1043 ± 162 In the 1990 experiment, geese adapted well to experimental conditions and grazed the untreated wheat heavily during the 2 days of acclimation. Almost no wheat remained in this pen after two days. Geese within the control (untreated) pen continued to graze heavily following their transfer to this pen, but feeding was minimal in the pen with Furadan-treated wheat. Avoidance of Furadan-treated wheat continued through the second day, despite the fact that there was no other food source. Wheat (above ground) within the control pen was essentially eliminated by the conclusion of the trial. When wheat samples were clipped and weighed from each pen the next morning, some recovery of grazed wheat was apparent. Still, only 2.03 ± 0.86 g remained in 0.785 m2 ~ plots in the control pen, significantly less (f < 0.05) than the 33.95 ± 9.33 g remaining in plots within the treatment pen. Avoidance of Furadan-treated wheat is significant, because large die-offs of geese and other waterfowl have occurred when alfalfa treated with Furadan 4F flowable was (apparently) eaten (Flickinger et al. 1980, reviewed in Smith 1987). Canada geese have been successfully deterred from feeding on rye and turf by methiocarb (another carbamate pesticide) application (Conover 1985, 1989), but methiocarb is substantially less toxic to birds than Furadan. Carbamate residues in treated wheat samples, adjusted for percent recovery, were 5.81 and 6.08 ppm. Dietary LC50 for mallards is 190 ppm (Smith 1987), over 30 times higher than levels measured in wheat. Mallard LD50's are substantially lower, in the range of 0.4-0.6 mgjkg (Smith 1987). A 2.5-kg Canada goose eating 0.35 kg of green wheat with a total carbamate level of 5.7 mg/kg would be exposed to a dose of 0.8 mgjkg body weight, or in excess of a mallard LD50. Thus, if geese had eaten large quantities of green wheat in this trial some mortality might have occurred. It is interesting that geese apparently eat enough Furadan-treated alfalfa to poison themselves yet avoid wheat containing potentially lethal levels. A possible explanation is that geese don't reject Furadan-treated vegetation on the basis of taste, but rather because of post-ingestive consequences such as feeling ill. Geese may sample alfalfa sprayed with Furadan 4F, be exposed to a lethal dose and die. Sampling wheat in this study would have exposed them to a sub-lethal dose that may have made them sick enough to avoid additional feedi~g. �339 Acetylcholinesterase (ChE) activity of brain tissue from geese in treatment and control pens did not differ (f < 0.05, Table 3). Plasma ChE was depressed (f < 0.05) an average of about 38% in birds exposed to Furadan treated wheat. Plasma ChE inhibition is a sensitive indicator of exposure to antiChE agents but is not in itself indicative of negative health consequences because the function of plasma ChE is not known (Kutty 1980). Plasma ChE may be inhibited by as much as 75% when brain ChE reaches a detectable and biologically significant 10-20% (Ludke et ale 1975). These results support the premise that initial feeding on treated wheat exposed geese to Furadan, but feeding ceased prior to significant brain ChE depression. Table 3. Brain and plasma acetylcholinesterase activity (mean ± SD) of Canada geese from pens containing Furadan-treated (n - 15) or untreated (n - 14) winter wheat, 1990. Plasmaa Brainb S.D. Untreated Treated 672.1 419.9 201.9 124.3 S.D. 5.57 5.58 0.83 1.48 &wu acetylthiocholine iodide hydrolyzed per min per ml of plasma at 25 C. b ~mol acetylthiocholine iodide hydrolized/g (wet weight) of brain tissue at 25 C. " Wildlife risks from microtubule injection of furadan appear slight. Residue levels in green wheat are low relative to LC50 or LD50 values of mallards or geese. Geese avoided eating treated wheat and kept intakes below levels that would reduce brain ChE. Risks to insectivorous birds are mitigated by timing of migrations and low furadan residues in grasshoppers. The primary risk appears to be to granivorous birds, principally horned larks and meadowlarks. Few unexplained mortalities were found, suggesting that losses were slight or nonexistent. LITERATURE CITED Bailey, A. M., and R. J. Niedrach. 1965. Birds of Colorado. Denver Mus. Nat. Rist. Denver, Colo. 895 pp. Vol. II. Conover, M. R. 1985. Alleviating nuisance Canada goose problems through methiocarb-induced aversive conditioning. J. Wildl. Manage. 49:631-636. 1989. Can goose damage to grain fields be prevented through methiocarb-induced aversive conditioning? Wildl. Soc. Bull. 17:172-175. Flickinger, E. L., K. A. King, W. F. Stout, and M. M. Mohn. 1980. Wildlife hazards from Furadan 3G applications to rice in Texas. J. Wildl. Manage. 44:190-197. �340 Guerra-Sobrevilla, L. 1988. Effectiveness of carbofuran applied to the soil and as a seed treatment for the control of aphids on wheat in northwestern Mexico. Crop Prot. 7:336-337. Hill, E. F., and W. J. Fleming. 1982. Anticholinesterase poisoning of birds: field monitoring and diagnosis of acute poisoning. Environ. Toxicol. Chem. 1:27-38. James, P. C., and G. A. Fox. 1987. Effects of some insecticides on productivity of burrowing owls. Blue Jay 45:65-71. Johnson, C. G., L. A. Nickerson, and M. J. Bechard. 1987. Grasshopper consumption and summer flocks of nonbreeding Swainson's hawks. Condor 89:676-678. Kutty, K. M. 1980. 13:239-243. Biological function of cholinesterase. Clin. Biochem. Littrell, E. E. 1988. Waterfowl mortality in rice fields treated carbamate, carbofuran. Calif. Fish and Game 74:226-231. with the Ludke, J. L., E. F. Hill, and M. P. Dieter. 1975. Cholinesterase (ChE) response and related mortality among birds fed ChE inhibitors. Arch. Environ. Contam. and Toxicol. 3:1-21. Rattner, B. A., L. Sileo, and C. G. Scanes. 1982. Hormonal responses and tolerance to cold of female quail following parathion ingestion. Pest. Biochem. Physiol. 18:132-138. Remington, T. E. 1990. Evaluation of wildlife responses to pesticides used in wheat farming. Colorado Div. Wildl. Job Prog. Rep., Fed. Aid Proj. W-152-R. Apr:253-264. Smith, G. J. 1987. Pesticide use and toxicology in relation to wildlife: organophosporous and carbamate compounds. U.S. Dep. Inter., Fish and Wildl. Servo Resour. Publ. 170. l7lpp. Woffinden, N. D. 1986. Notes on the Swainson's hawk in central Utah: insectivory, premigratory aggregations, and kleptoparasitism. Great Basin Nat. 46:302-304. Prepared by t. Thomas E. Remington Wildlife Researcher C �)41 JOB PROGRESS REPORT Colorado State of: Project: W-167-R Upland Bird Research Work Plan: 26 Job Title: Analysis of Upland Bird Population Trends Period Covered: Author: Job _1_ 01 January through 31 December 1991 Clait E. Braun Personnel: Clait E. Braun, Kenneth M. Giesen, Richard W. Hoffman, Thomas E. Remington, and Warren D. Snyder, Colorado Division of Wildlife ABSTRACT The following were prepared in 1991. Braun, C. E. 1991. 1991. Blue Mountain sage grouse harvest data, 1976-91. Cold Spring Mountain harvest data, 1976-91. 1991. Sage grouse harvest data, Eastern Moffat and Western Routt counties, Colorado, 1976-91. 1991. Eagle County sage grouse harvest data, 1991. 1991. Gunnison Basin sage grouse harvest data, 1991. 1991. Middle Park sage grouse harvest data, 1991. 1991. Northcentral Moffat County sage grouse harvest data, 1976-91. 1991. North Park sage grouse harvest data, 1991. 1991. Piceance Basin sage grouse harvest data, 1991. 1991. Yampa Area sage grouse harvest data, 1991. _____ , T. E. Remington, and W. D. Snyder. 1991. Habitat development programs: analysis and recommendations. Colorado Div. Wild1. Unpub1. rep. Fort Collins. 23pp. Giesen, K. M. 1991. Columbian sharp-tailed grouse harvest data, northwest Colorado, 1976-91. '. � https://cpw.cvlcollections.org/files/original/5c482de6ffb17ce3b1d181fcb81e4186.pdf dc06c892556d660e969b90e8c9ddaca6 PDF Text Text Colorado Division of Wildlife Wildlife Research Report July 1992 JOB PROGRESS REPORT State of Colorado Mammals Research Proj ect No. _W~-.::!:.15::::.;3~-...IR~--=5~ _ • Work Plan No. Mu1tispecies 1 Job No. Mammals Publication, Editing, and Library Services Period Covered: Author: Investigations July 1, 1991 - June 30, 1992 J. A. Boss Personnel: J. A. Boss, N. W. McEwen ABSTRACT During the Segment the following were accomplished: * 24 publications were purchased at the request of Wildlife Researchers and placed into the Colorado Division of Wildlife Research Library Collection. * 26 Theses or books were obtained on Interlibrary Loan or as gifts for use by Mammals Researchers. * * 15 manuscripts were published or accepted for publication. 6 manuscripts were prepared and submitted for peer review. ��3 MAMMALS PUBLICATION. EDITING AND LIBRARY SERVICES Jacqueline A. Boss P. N. OBJECTIVE To provide a centralized support program for manuscript editing and library services to facilitate publishing results of research conducted by staff of Federal Aid Project W-153-R . . SEGMENT OBJECTIVE To provide a centralized support program for Mammals Research editing, library, and publishing services so that Mammals Research personnel can be most efficient in publishing results of their research. ··SUMMARY OF SERVICES Publications Purchased with Mammals Research funds and Placed in the Research Center Library Agresti, A. 558pp. 1990. Categorical data analysis. New York; John Yiley & Sons. Bell, S. S., E. D. McCoy, and H. R. Mushinsky, eds. 1991. Habitat structure: the physical arrangement of objects in space. New York; Chapman & Hall. 438pp. Chatfield, C. 1989. Analysis of time series: an introduction. 4th edition. New York; Chapman & Hall. 241pp. Colgan, P. 1989. Animal motivation. Cressie, N. A. C. 1991. Sons. 900pp. New York; Chapman & Hall. Statistics for spatial data. l59pp. New York; John Wiley & Darling, L. M. 1990. Bears - their biology and management. International conference on bear research and management (8th: 1989: Victoria, British Columbia). Victoria, BC; T. D. Mock & Associates. 448pp. Dwight, H. J. 1971. The application of an antifertility agent in the control of a white-tail deer population. Ann Arbor, MI; University Microfilms. l62pp. Ehrenfeld, D. 1981. Press. 286 pp. The arrogance of humanism. New York; Oxford University Fan, L. T., D. Neogi, and M. Yashima. 1991. Elementary introduction to spatial and temporal fractals. New York: Springer-Verlag. l68pp. �4 G1adders, D., and N. Jotham, Coordinators. (1988). Proceedings: International Symposium on Trapping Wild Furbearers. Toronto, Ont.; Fur Institute of Canada. up. Gould, S. J. 1989. Wonderful life: the Burgess Shale and the nature of history. New York: W. W. Norton & Company. 347pp. Halfpenny, J. 1986. A field guide to mammal tracking in North America. Boulder, CO; Johnson Books. 16lpp. Hilfiker: E. L. 1991. Beavers: water, wildlife and History. Windswept Press. 197pp. Hoffmeister, D. F. 1986. Mammals of Arizona. Arizona Press. 602pp. Hosmer, D. W., and S. Lemeshow. 1989. York; John Wiley & Sons. 307pp. Interlaken, NY; [Tucson, AZ]; University of Applied logistic regression. New Hudson, R. J., K. R. Drew, and L. M. Baskin, eds. 1989. Wildlife production systems: economic utilization of wild ungulates. New York; Cambridge University Press. 469 pp. Knobil, E., and J. D. Neill, eds. York; Raven Press. 2 vo1s. 1988. The physiology of reproduction. New Li, H. 1989. Spatio-temporal pattern analysis of managed forest landscapes: a simulation approach. Ann Arbor, MI; University Microfilms International. l66pp. Palo, R. T., and C. T. Robbins. 1991. Plant defenses against mammalian herbivory. Boca Raton, FL; CRC Press. 192pp. Peterle, T. J. 1991. Wildlife toxicology. New York; Van Nostrand. 322pp. Renecker, L. A., and R. J. Hudson, eds. 1991. Wildlife production: conservation and sustainable development. AFES misc. pub. 91-6. Fairbanks, AK; University of Alaska-Fairbanks. 60lpp. Roberts, E. A. 1992. Sequential data in biological experiments: an introduction for research workers. New York; Chapman & Hall. 240pp. Southeastern Association of Fish and Wildlife Agencies. [1991]. Proceedings of the forty-second annual conference; Southeastern Association of Fish and Wildlife Agencies, November 6-9, 1988, Hilton Head Island, SC. 605pp. Servheen, C. 1990. Status and conservation of the bears of the world. Victoria, BC; T. D. Mock & Associates. 32pp. In addition to books purchased with Federal Aid Funds, about 7 free reports and short publications from state or federal agencies or from private sources were located, ordered, and obtained for use by Mammals Research personnel. �5 Theses and Books Obtained on Interlibrary Loan or as Gifts for Use by Researchers Allen, R. B. 1985. Research and management implications of the pursuit of black bears with trained bear dogs. M.S. Thesis, University of Montana, Missoula, MI. 5lpp. Alt, G. L. 1989. Reproductive biology of female black bears and early growth and development of cubs in northeastern Pennsylvania. Ph.D. Dissertation, West Virginia University, Morgantown, WV. l16pp . . Anderson, R. M., B. D. Turner, and L. R. Taylor, eds. 1979. Population dynamics: the 20th symposium of the British Ecological Society. Oxford: Blackwell Scientific Publications. 434pp. Beecham, J. J. 1980. Population characteristics, denning, and growth patterns of black bears in Idaho. Ph. D. Diss., University of Montana, Missoula, MI. 101pp. Berg, H. H. 1983. Random walks in biology. Princeton, NJ. l42pp. Princeton University Press, Davis, L. R. and R. E. Marsh, eds. 1990. Proceedings: vertebrate pest conference (14th: 1990: Sacramento, CA). University of California, Davis. 372pp. Feynman, R. P. 1988. "What do you care what other people think?" further adventures of a curious character. New York: W. W. Norton & Company. 255pp. Frost, H. C. 1990. Population and reproductive characteristics of black bears on an isolated mountain in southeastern Utah. M.S. Thesis, Brigham Young University, Provo, UT. 45pp. Graber, D. M. 1982. Ecology and management of black bears in Yosemite National Park: final report to the National Park Service. University of California, Davis, CA. 205pp. Keay, J. A. 1990. Black bear population dynamics in Yosemite National Park. Ph. D. Diss., University of Idaho, Moscow, 10. l26pp. Knowles, W. R., Jr. 1989. A national comparison of structural factors affecting participation in selected wildlife-related activities. M.S. Thesis, Texas A & M University, College Station, TX. 87pp. Koch, D. B. 1983. Population, home range, and denning characteristics of black bears in.Placer County, California. M.S. Thesis, California State University, Sacramento, CA. 7lpp. Levi-Montalcini, R. York. 220pp. 1988. In praise of imperfection. Basic Books, Inc., New �6 Li, H. 1989. Spatio-tempora1 pattern analysis of managed forest landscapes: a simulation approach. M.S. Thesis, Oregon State University, Corvallis, OR. 166pp. Malvil1e, L. E. 1990. Movements, distribution, and habitat selection of river otters reintroduced into the Dolores River, southwestern Colorado. M.A. Thesis, University of Colorado, Boulder, CO. 67pp. Organ, J. F. 1989. Mercury and PCB residues in Massachusetts river otters: comparisons on a watershed basis. Ph. D. Diss., University of Massachusetts, Amherst, MA. 69pp. Risenhoover, K. L. 1987. Winter foraging strategies of moose in subarctic and boreal forest habitats. Ph. D. Diss., Michigan Technological Univ., Houghton, MI. l20pp. Rohlman, J. A. 1989. Black bear ecology near Priest Lake, Idaho. Thesis, University of Idaho, Moscow, ID. 76pp. M.S. Ropek, M. M. 1990. Mercury levels in Michigan River otters in relation to population characteristics and habitat. M.S. Thesis, Eastern Michigan University, Ypsilanti, MI. 6lpp. Rose, C. L. 1990. Application of the carbon/nitrogen balance concept to predicting the nutritional quality of blueberry foliage to deer in southeastern Alaska. Ph. D. Diss., Oregon State University, Corvallis, OR. 16Opp. Ruther, S. A. 1988. Urban wildlife conservation in Arizona: public opinion and agency involvement. M.S. Thesis, University of Arizona, Tempe, AZ. 9pp. Seber, G. A. F. 1982. The estimation of animal abundance and related parameters. 2nd ed. Macmillan Publications, New York. 654pp. Sweanor, L. L. 1990. Mountain lion social organization in a desert environment. M.S. Thesis, University of Idaho, Moscow, ID. Smith-Swanson, S. A. 1990. Activities and habitat use of black bears in north-central Minnesota. M.S. Thesis, University of Minnesota, St. Paul, MN. 75pp. United States. Bureau of Outdoor Recreation. 1975. Proposed Bruneau Wild and Scenic River, Idaho. U.S. Bureau of Outdoor Recreation, Northwest Regional Office, Seattle, WA. 56pp. White, P. J. 1990. The pathological response of red foxes to unpadded foothold traps. M.S. Thesis, University of Minnesota, St. Paul, MN. 55pp. The Research Center Library staff also located and delivered about 545 individual articles on request for Mammals Researchers during this segment; about 15 were not available locally and were obtained through interlibrary loan procedures. �7 Manuscripts Published FY 1991-92 Job Progress Reports; Federal Aid. All studies. Andelt, W. F., D. L. Baker, and K. P. Burnham. 1992. Relative preference of captive cow elk for repellent-treated diets. J. Wildl. Manage. 56(1):164-173. Anderson, A. E. 1992. The puma on Uncompahgre Plateau, Ccolorado. Div. Wildl. Tech. Publ. No.40. Colo. I Bartmann, R. M., G. C. White, and L. H. Carpenter. mortality in a Colorado mule deer population. 1992. Compensatory Wildl. Monogr. 121. Beck, T. D. I. 1991. Black bears of west-central Colorado. Wild1. Tech. Publ. No. 39. 86pp. 37pp. Colo. Div. Freddy, D. J., E. R. Ryland, and R. M. Hopper. 1991 Colorado's wildlife ranching program: the Forbes Trinchera experience. In: Wildlife production: conservation and sustainable development. eds. L. A. Renecker, and R. J. Hudson, p.336-343. AFES misc. pub. 91-6. University of Alaska Fairbanks. Fairbanks, Alaska. Gill, R. B., and T. D. I. Beck. 1991. Black bear status report: Colorado. W. Black Bear Workshop, Proc. 7 (in press) Gross, J. E., L. A. Shipley, N. T. Hobbs, D. E. Spalinger, and B. A. Wunder. 1992. Foraging by herbivores in food-concentrated patches: tests of a mechanistic model of functional response. Ecoloy. (in press) Hobbs, N. T., and M. W. Miller. 1992. Interactions between pathogens and hosts: simulation of pasteurellosis epizootics in bighorn sheep popUlations. In: Wildlife 2001: populations. D. R. McCullough and R. H. Barrett, eds., Elsevier Science Publishers, Ltd., London, England, (in press) Miller, M. W., N. T. Hobbs, and E. S. Williams. 1991. Spontaneous pasteurellosis in captive Rocky Mountain bighorn ship (Ovis canadensis canadensis): clinical, laboratory, and epizootiological observations. J. Wildl. Dis. 27: 534-542. Miller, M. W., J. M. Williams, T. J. Schiefer, and J. W. Seidel. 1991. Bovine tuberculosis in a captive elk herd in Colorado: epizootiology, diagnosis, and management. Proc. U.S. Anim. Health Assoc. 95: 533-542 Rbyan, J. C., D. A. Saari, E. S. Williams, M. J. Wilson. 1992. Gross and microscopic tuberculosis in a captive herd of wapiti Colorado. J. Vet. Diagn. Invest. 4: (in W. Miller, A. J. Davis, and A. lesions of naturally occurring (Cervus elaphus nelsoni) in press) Snipes, K. P., R. W. Kasten, M. A. Wild, M. W. Miller, D. A. Jessup, R. L. Silflow, W. J. Foreyt, and T. E., Carpenter. 1991. Using ribosomal RNA gene restriction patterns in distinguishing isolates of Pasteurella haemolytica from bighorn sheep (Ovis canadensis). J. Wildl. Dis. 28: 347-354. �8 Spa1inger, D. E., and N. T. Hobbs. 1992. Mechanisms of foraging in vertebrate herbivores: new models of functional response. Am. Nat. 140:325-348. Thorne, E. T., M. W. Miller, D. L. Hunter, and E. s. Williams. 1992. Wildlife management agency concerns about bovine tuberculosis in captive cervidae. Proc. Bovine Tuberculosis in Cervidae Symposium. USDA/APHIS. (in press) Williams, E. 5., M. W. Miller, S. Young, and E. T. Thorne. 1992. Chronic wasting disease: a spongiform encephalopathy of mule deer (Odocoileus heminonus) and Rocky Mountain elk (Cervus elaphus nelsoni) in Colorado and Wyoming, USA. Proc. World Assoc. Vet. Microbio1. Immuno1. 12: (in press) Manuscripts in Review FY 1991-92 Pojar, T. M. 1991. Census techniques. In: Pronghorn management. ed. R. McCabe. Wildlife Management Institute, Washington D.C. Submitted March 6, 1991. 1991. ed. R. McCabe. March 6, 1991. The use of population models. In: Pronghorn management. Yi1d1ife Management Institute, Washington D.C. Submitted ___________ , D. C. Bowden, and R. B. Gill. 1991. techniques for pronghorn. J. Wild1. Manage. Evaluation of census (in review) Ringe1man, J. K., M. W. Miller, and W. F. Ande1t. 1992. Effects of ingested tungsten-bismuth-tin shot on mallards. J. Wildl. Manage. Torbit, S. C., R. B. Gill, A. W. Alldredge, and J. A. Liewer. 1993. Impacts of pronghorn grazing on winter wheat in Colorado. J. Wildl. Manage. (in press) Wild, M. A., M. W. Miller, D. L. Baker, R. B. Gill, N. T. Hobbs, and B. J. Maynard. 1992. Hand-raising wild neonates using an evaporated milk diet fed ad libitum: evaluation in bighorn sheep, pronghorn antelope and elk. Can. J. Zool. (in review) �9 Colorado Division of Wildlife Wildlife Research Report July 1992 JOB PROGRESS REPORT State of C~o~l:!:.:o~r!:.!a~d~o~ _ Project No. W-lS3-R- 5 Mammals Research Work Plan No. 1 Multispecies Job No. 9 Mammals 1 Research Administration Period Covered: Author: Investigations July I, 1991-June 30, 1992 R. B. Gill Personnel: R. B. Gill, L. E. Lovett, and D. K. Hall Abstract Accomplishments of this job are summarized in the Job Progress Report for W -lS3R-S Work Plan LA Job 3. . . '.' . . Wildlife .ResearchLeader ��11 Colorado Division of Wildlife Wildlife Research Report July, 1992 JOB PROGRESS REPORT State of Colorado Project No. ~W_-~1~5~3~~R~-5~ _ Mammals Research Work Plan No. =2 _ Deer Investigations Job No. 7 Period Covered: Author: Development of Census Methods for Deer in Plains Riverbottom habitats July 1, 1991 - June 30, 1992 R. C. Kufeld Personnel: D. Bowden, D. Younkin ABSTRACT White-tailed and mule deer, radio-collared in the Arkansas Riverbottom during January, 1991, were located at approximately 2-week intervals through December, 1991. Movement data from 50 deer, radio-collared as adults, (26 mule deer and 24 whitetails) suggest that adult deer in the South Platte Riverbottom fall into 4 movement categories. These categories include resident deer which occupy the same general area yearlong, and migratory deer which occupy separate winter and summer areas. These patterns were observed for both mule deer and whitetails and are described in detail including sizes of seasonal areas used. Dispersal of deer, eartagged as fawns, of up to 149.3 km was recorded for mule deer and up to 130 km for whitetails. Among deer radio-collared in the South Platte Riverbottom as adults 73% of the mule deer and 67% of the whitetails were nonmigratory. Most of the nonmigratory deer of both species lived in rhe riverbottom yearlong, but some, after being tagged in the riverbottom, established yearlong home ranges on the plains away from the river. All of the migratory mule deer'and most of the migratory whitetails followed a pattern of migration,'in late spring or summer, from the riverbottom to the plains with return l~ter in the summer or in the fall, but some whitetails migrated ,atvarious 'times of the year to distant sites within the riverbottom. Migratory deer of both species exhibited strong fidelity to their riverbottom and plains home ranges, returning to the same areas each winter and summer. Adult radio-collared white-tailed deer in this study were observed to occupy larger minimum convex polygon areas and to have longer movements in general than did the adult instrumented mule deer. Our findings also suggest that white-tailed deer in plains riverbottom habitats in eastern Colorado are considerably more mobile than whitetails in most other parts of the u.S. ��13 .DEVELOPMENT OF CENSUS METHODS FOR DEER IN PLAINS RIVERBOTTOM HABITATS Roland C. Kufeld P. N. OBJECTIVES 1. To determine seasonal movements and home range size of white-tailed and mule deer in plains riverbottom habitats. 2. To develop and test methods for estimating size of deer populations in plains riverbottom habitats. SEGMENT OBJECTIVE To determine seasonal movements and home range size of white-tailed and mule deer in plains riverbottom habitats. STUDY AREA The South Platte River study area was described by Kufeld (1989), and the Arkansas River Study area by Kufeld (1991). METHODS AND MATERIALS White-tailed and mule deer, radio-collared in the South Platte Riverbottom during January and February, 1987, 1988, and 1989, (Kufeld 1987, 1988, 1989, 1990,), were located at approximately 2-week intervals from January, 1987 through December, 1990. White-tailed deer, radio-collared in the Lower Arkansas Riverbottom during January, 1991 (Kufeld 1991), were located at approximately 2-week intervals from January, 1991, through December, 1991. Most locations were made by aerial telemetry using a Cessna 185 aircraft with a 2 element, "H" configuration receiving antenna mounted on each strut. A switchbox permitted the telemetry operator, a passenger in the aircraft, to operate antennas jointly or separately. W