https://cpw.cvlcollections.org/files/original/855270b8c56c4882d26973f2bb79d59d.pdf c774ad9e3262e07cc79bf2b42afce352 PDF Text Text CPW 2018 White-tailed Ptarmigan Southern White-tailed Ptarmigan (Lagopus leucura altipetens) Population Assessment and Conservation Considerations in Colorado Final Report 2018 Colorado Parks and Wildlife Amy Seglund, Colorado Parks and Wildlife, 2300 South Townsend, Montrose, CO 81403 amy.seglund@state.co.us Phillip A. Street, Program in Ecology, Evolution and Conservation Biology University of Nevada Reno, 1664 N. Virginia St., Reno, NV 89557 pstreet@cabnr.unr.edu Kevin Aagaard, Colorado Parks and Wildlife, 317 W Prospect Rd., Fort Collins, CO 80526 kevin.aagaard@state.co.us Jon Runge, Colorado Parks and Wildlife, 317 W Prospect Rd., Fort Collins, CO 80526. jon.runge@state.co.us Michelle Flenner, Colorado Parks and Wildlife, 317 W Prospect Rd., Fort Collins, CO 80526. michelle.flenner@state.co.us. 1 Page �CPW 2018 White-tailed Ptarmigan Abstract Status of the southern white-tailed ptarmigan (Lagopus leucura altipetens) in Colorado was assessed from 2013-2017 using a number of metrics to determine trends in abundance, survival, site fidelity, reproductive success, resource selection, and genetic structure. The species inhabits naturally fragmented alpine habitats that have been, and are currently impacted by anthropogenic threats that predominantly include climate change, sheep grazing, hunting, mining, and recreation. Fine-scale genetic structure was apparent between the San Juan Mountains (South population), and those in the central and northern mountain ranges (North population). Though some isolated pockets of white-tailed ptarmigan reside in the state (i.e., Flat Tops and Sangre de Cristo), there is adequate gene flow across Colorado to maintain high genetic diversity with currently no indications of severe effects of small population sizes. An Integrated Population Model was developed to assess populations at multiple spatial scales and a subsequent Population Viability Model produced to evaluate extinction probabilities 100 years into the future. Overall population trends for the state showed little evidence of an increase or decrease with abundance estimates ranging from a high in 2013 of 221,555 birds (CI = 178,615268,548) to a low of 147,798 birds (CI=128,289-171,563) in 2014. Local survey sites also appeared to be stable with regards to abundance estimates during our four year survey effort with the exception of one. We believe the observed decline at this site was the consequence of localized increases in human recreation and a resultant apparent movement of birds as well as extreme snow years that impacted productivity. Statewide estimated extinction probabilities were low (4% in 100 years; CI=0-0.17) with the North population having a higher projected extinction rate (0.42, CI=0.17-0.70) than the South population (0.10, CI=0.0-0.33). When potential immigration rates were modeled, extinction projections were reduced to 0% for all populations even with the inclusion of weak immigration (immigration parameter = -0.2). 2 Page �CPW 2018 White-tailed Ptarmigan Not unlike other studies conducted in the late 1960s and continuing until today (e.g., Braun and Rogers 1971, Martin and Wilson 2011, Wann 2017), we found that white-tailed ptarmigan have low reproductive success with high annual variability mostly driven by predation and to a lesser extent by weather. Mean probability of a white-tailed ptarmigan nest surviving until hatch was 0.393 (SE=0.07) with average clutch size of 5.46 (range 4-7). Survival of brood to fledging was highly variable (0.047-0.781) across sites and years. We attempted to model changes in white-tailed ptarmigan distribution under two climate change emission scenarios. Unfortunately, the resolution available to assess white-tailed ptarmigan resource use was insufficient to identify predictor variables. However, our results indicated that our defined Predicted Range Model was accurate at identifying suitable habitat for the species, emphasizing the importance of protecting the entirety of Colorado’s alpine to maintain viable populations of white-tailed ptarmigan. The overall indication from our work is that the southern white-tailed ptarmigan is a resilient species occupying all suitable habitats in the alpine, with stable populations in Colorado and low predicted extinction into the future. We recommend the development of a long-term monitoring plan to continue to assess changes in distribution and to evaluate demographic parameters as environmental changes become more pronounced. It is imperative for agencies to coordinate on the development of management practices to address increased recreation in the alpine, use adaptive management to deal with domestic sheep grazing as the state warms and climate conditions change, and continue the cleanup and closure of historic mine sites. Finally, effective methods to assess hunting pressure of white-tailed ptarmigan at localized areas that may be over exploited as a consequence of easy access and proximity to human population centers should be considered. 3 Page �CPW 2018 White-tailed Ptarmigan Acknowledgements This project would not have been possible without the dedication of hard working technicians and biologists that endured arduous hikes, long days of surveying, and constant inclement weather. These technicians included B. Bartz, M. Butnyski, A. Clifford, A. Dyson, J. Ellison, T. Johnson, S. Jordan, E. Latta, M. Leigh, H. Mackey, M. Markus, N. Myer, T. Peltier, E. Phillips, K. Rennie, J. Schas, R. Taylor, and R. Wertsbaugh. I would especially like to thank K. Bernier, L. Kaiser, and S. Rocksund who worked on the project during all survey years. They were excellent at training and guiding crews; they captured and banded the majority of birds over the study, and provided excellent input on ways to improve the project and insight into the biology of the bird. Their dedication to the project was invaluable. I appreciate S. Conner for his constant willingness to volunteer for surveys and to listen to my regular babbling regarding white-tailed ptarmigan. S. Waters conducted all of our winter survey flights and located missing white-tailed ptarmigan providing us with exceptional data for winter habitat use and movement by white-tailed ptarmigan. K. Langin and S. OylerMcCance completed all of the genetic analysis. Finally, I would like to thank G. Wann for introducing me to white-tailed ptarmigan and teaching my crews how to safely capture and process a bird. He was a wealth of information on the bird’s biology and behavior as well as helping with study design and developing questions that needed answering. This project would not have been possible without his guidance and assistance. Kathryn Bernier releasing a white-tailed ptarmigan, Serena Rocksund at Byers Peak, and Lee Kaiser whispering to birds 4 Page �CPW 2018 White-tailed Ptarmigan Table of Contents Abstract .......................................................................................................................................................................... 2 Acknowledgements ................................................................................................................................................... 4 Table of Contents ........................................................................................................................................................ 5 List of Tables and Figures ....................................................................................................................................... 7 Chapter 1...................................................................................................................................................................... 14 General Overview ..................................................................................................................................................... 14 Taxonomy ............................................................................................................................................................... 17 White-tailed Ptarmigan Natural History ................................................................................................... 21 Chapter 2...................................................................................................................................................................... 25 Threats Assessment ................................................................................................................................................ 25 Climate Change..................................................................................................................................................... 25 Grazing by Domestic Livestock ..................................................................................................................... 30 Hunting .................................................................................................................................................................... 31 Mining ...................................................................................................................................................................... 32 Recreation .............................................................................................................................................................. 35 Chapter 3...................................................................................................................................................................... 37 Population Dynamics .............................................................................................................................................. 37 Introduction .......................................................................................................................................................... 37 Study Areas ............................................................................................................................................................ 38 Field Methods ....................................................................................................................................................... 53 5 Page �CPW 2018 White-tailed Ptarmigan Analysis ................................................................................................................................................................... 60 Results ..................................................................................................................................................................... 69 Discussion .............................................................................................................................................................. 86 Chapter 4...................................................................................................................................................................... 97 Reproductive Output .............................................................................................................................................. 97 Introduction .......................................................................................................................................................... 97 Study Sites .............................................................................................................................................................. 98 Field Methods ....................................................................................................................................................... 98 Analysis ................................................................................................................................................................ 103 Results .................................................................................................................................................................. 105 Discussion ........................................................................................................................................................... 120 Chapter 5................................................................................................................................................................... 126 Resource Selection ................................................................................................................................................ 126 Introduction ....................................................................................................................................................... 126 Methods................................................................................................................................................................ 126 Results .................................................................................................................................................................. 128 Discussion ........................................................................................................................................................... 133 Management Implications ................................................................................................................................. 136 Conclusions .............................................................................................................................................................. 140 References ................................................................................................................................................................ 141 6 Page �CPW 2018 White-tailed Ptarmigan List of Tables and Figures Table 1. Measures of genetic diversity for Colorado, for the South population (San Juan Mountains) and the North population (all other mountain ranges in the state), and for each individual site where feathers and blood were collected from captured white-tailed ptarmigan. Columns show sample size (n), rarefied allelic richnes, and expected heterozygosity. Statistics were calculated using the FSTAT program. At the population and individual site level for allelic richness, the FSTAT program uses the smallest sample size to subsample and if there are missing data at a locus, a sample is not incorporated. This is why the sample was four in the individual site analysis and 93 for the population analysis. ....................................................................................................................................... 20 Figure 1. Average daily temperatures for summer months (June-August) recorded at Snow Telemetry (SNOTEL) Natural Resource Conservation Service (NRCS) National Water and Climate Center data near three survey sites in Colorado. Mean temperature began to be recorded at all sites in the mid-1980s. The Independence Pass SNOTEL site is the closest station to the Independence Pass and Mt. Yale survey sites. Red Mountain is close to the Ophir survey site and Slumgullion is closest to the Mesa Seco survey site. Date were collected at survey sites from 2013-2017. ........................................................................................................................................................................................................ 29 Figure 2. Active mining claim records intersected with the southern white-tailed ptarmigan predicted range model for Colorado. ....................................................................................................................................................................................... 34 Figure 3. Overview map of capture-mark-recapture survey locations sampled in 2013-2016 for white-tailed ptarmigan in Colorado and for breeding propensity, nest, and chick survival surveys from 2013-2017. Sites are overlaid on the Predicted Range Model for the species with three sites located in the North population and three sites in the South population defined by fine-scale genetic structure. ...................................................................................... 40 Figure 4. Byers Peak survey site for capture-mark-recapture surveys conducted in Colorado for white-tailed ptarmigan from 2013-2016. Surveys were conducted within the red polygon during the breeding, brood rearing, and fall primary periods. Survey boundaries were adjusted for the 2014 and 2015 breeding surveys due to heavy snow cover that caused areas of the site to be inaccessible. ......................................................................................................... 41 Figure 5. Emerald Lake survey site where capture-mark-recapture surveys were conducted from 2013-2016 in Colorado for white-tailed ptarmigan during the breeding, brood rearing, and fall primary periods. ........................ 43 7 Page �CPW 2018 White-tailed Ptarmigan Figure 6. Independence Pass survey site for capture-mark-recapture surveys conducted in Colorado for whitetailed ptarmigan from 2013-2016. Surveys were conducted within the red polygon during the brood rearing, and fall primary periods. Survey boundaries were adjusted for the 2014 and 2015 breeding surveys due to heavy snow cover that caused some areas of the site to be inaccessible. Breeding propensity, nest, and chick survival were evaluated at this site from 2014-2017. ....................................................................................................................................... 45 Figure 7. Mesa Seco sample area for capture-mark-recapture surveys conducted in Colorado for white-tailed ptarmigan from 2013-2016. Surveys were conducted within the red polygon during the breeding, brood rearing, and fall primary periods. Survey boundaries were adjusted for the 2014 and 2015 breeding surveys due to heavy snow cover making some areas of the site inaccessible. Breeding propensity, nest, and chick survival evaluated at this site from 2013-2017. ............................................................................................................................................................................ 47 Figure 8. Mt. Yale sample area for capture-mark-recapture surveys conducted in Colorado for white-tailed ptarmigan from 2013-2016. Surveys were conducted within the red polygon during the breeding, brood rearing, and fall primary periods. Survey boundaries were adjusted for the 2014 and 2015 breeding surveys due to heavy snow cover the cause areas of the site to be inaccessible. Breeding propensity, nest, and chick survival evaluated at this site from 2013-2017. ....................................................................................................................................................................... 49 Figure 9. Ophir sample area for capture-mark-recapture surveys conducted in Colorado for white-tailed ptarmigan from 2013-2016. Surveys were conducted within the red polygon during the breeding, brood rearing, and fall primary periods. Survey boundaries were adjusted for the 2014 and 2015 breeding surveys due to heavy snow cover causing some areas of the site to be inaccessible. Breeding propensity, nest, and chick survival evaluated at this site from 2013-2017. .................................................................................................................................................. 51 Photo 7. Uniquely number banded female white-tailed ptarmigan with attached radio-collar ................................... 53 Figure 10. Robust design was used in combination with Huggins closed capture model to estimate abundance of white-tailed ptarmigan for each primary occasion ( ). For each time interval between primary occasions, the Robust design model estimates apparent survival ( ), a combination of true survival and permanent emigration (note that we used estimates from true survival from telemetry data alone in our analysis and ignore the apparent survival estimated here). Temporary immigration was also estimated. white-tailed ptarmigan detected during is the probability that a survived time interval , but is unavailable for detection ( primary period because it has left the study plot. in is the probability that an individual that was not on the 8 Page �CPW 2018 White-tailed Ptarmigan study plot and unavailable for detection during primary period unavailable for detection during primary period remains off of the study plot and is Within each primary period there are secondary occasions. ............................................................................................................................................................................................................................... 58 Table 2. Total area surveyed for capture-mark-recapture surveys at six survey sites during three seasons for white-tailed ptarmigan in Colorado from 2013-2016. Only a survey during the brood rearing primary period was completed in 2016. ......................................................................................................................................................................................... 59 Figure 11. Three levels of immigration that were investigated in the Population Viability Analysis. Base function was number of immigrants = (abundance) (eimm * abundance). Number of immigrants is on the y-axis, abundance is on the x-axis, different levels of imm are represented by the different lines. .......................................................................... 68 Table 3. White-tailed ptarmigan density estimates (bird/km2) with associated 95% confidence intervals for six study sites for adult and subadult birds, per season, and per year in Colorado from 2013-2015 (2016 was not included in analysis as only a brood rearing season was conducted that year). Some sites were not accessible in late spring to conduct breeding surveys consequently surveys were not conducted (NC). Abundance estimates were derived from the Robust design analysis. Detection probability was constrained to remain constant across all plots and all occasions. Biologically, white-tailed ptarmigan behave differently during survey periods and conditions for surveys can vary. ............................................................................................................................................................... 70 Table 4. White-tailed ptarmigan abundance estimates for the entire state of Colorado and for the North and South populations from 2013-2016. Included with estimates are the lower and upper 95% credible intervals. ... 72 Figure 12. White-tailed ptarmigan abundance estimates for the entire state of Colorado and for the North and South populations from 2013-2016. Each survey was conducted during the brood rearing season when hens would respond to chick distress playbacks and males would respond to male territorial playback calls. Estimates were obtained from an Integrated Population Model. We found little evidence for a trend over time at either the state level or population level. .................................................................................................................................................................. 73 Figure 13. Abundance estimates of adult white-tailed ptarmigan from six study sites in Colorado. Each survey was conducted during the brood rearing season when hens would respond to chick distress playbacks and males would respond to male territorial playback calls. Estimates were obtained from an Integrated Population Model. We found little evidence for a trend over time at either the state level or population level, but evidence for a 9 Page �CPW 2018 White-tailed Ptarmigan negative trend at the Ophir site. Yellow boxplots represents sites in the North population and red represents those sites surveyed in the South population. ..................................................................................................................................... 74 Figure 14. Abundance estimates of white-tailed ptarmigan chicks from six study sites in Colorado. Each survey was conducted during the brood rearing season when hens would respond to chick distress playbacks and the number of chicks with marked and unmarked hens could be counted. Estimates were obtained from an Integrated Population Model. Yellow boxplots represents sites in the North population and red represents those sites surveyed in the South population. ................................................................................................................................................. 75 Table 5. Summary of distances moved during two defined seasons: summer (May 15-October 31) and winter (November 1-May 14) by 126 radio-collared white-tailed ptarmigan in Colorado from 2013-2017. ......................... 76 Figure 15. The probability of a white-tailed ptarmigan transitioning off of a survey site between the breeding, and brood rearing period for both males and females in Colorado 2013-2016. When birds were captured, they were either a subadult or an adult. Each adult captured was considered to be a minimum age of two, and only advanced in age if they were detected in multiple years of the study. ...................................................................................... 77 Figure 16. The probability that a white-tailed ptarmigan will transition back to the site where it was originally captured in Colorado prior to the onset of the breeding season. Since birds have to transition off of a site before they can come back and chicks were not marked, two is the minimum age a bird can transition back to the original plot of capture. ............................................................................................................................................................................... 78 Figure 17. Annual female survival estimates from 2013-2016 for individual survey site locations. Survival estimates are from breeding season to breeding season and estimates are based solely on radio-collared ptarmigan. Yellow boxplots represents sites in the North population and red represents those sites surveyed in the South population .................................................................................................................................................................................... 80 Figure 18. Annual female survival estimates from 2013-2016 for the North and South populations and statewide. Survival estimates are from breeding season to breeding season and estimates are based solely on radio-collared ptarmigan. Yellow boxplots represents the North population and red represents sites surveyed in the South population. ........................................................................................................................................................................................................ 81 Figure 19. Monthly adult survival modeled as a seasonal effect. May - June were considered to be the breeding period, July - August as brood rearing, September - October as fall, and November-April of the following year as winter. This seasonal effect was modeled with an additive structure with each year population combination. 10 Page �CPW 2018 White-tailed Ptarmigan Thus the pattern will be the same regardless of the population or year, but the estimates will be shifted up or down depending on the population and year combination. For simplicity of the figure, we chose to show only the North population in 2013. .......................................................................................................................................................................... 82 Table 6. Extinction probabilities (and 95% CIs) estimated from a Population Viability Analysis using data from six survey sites across Colorado from 2013-2016 and assuming no immigration. Extinction probabilities were calculated for the entire state, the North and South populations. ............................................................................................. 84 Figure 20. Projected extinction rates 100 years in the future for white-tailed ptarmigan in Colorado based on a Population Viability Analysis and assuming no immigration. Yellow represents the 95% credibility interval for sites in the North population, red represents the 95% credibility interval for those sites surveyed in the South population and brown is statewide. ........................................................................................................................................................ 85 Table 7. Estimated breeding densities (birds/km2) of white-tailed ptarmigan at study plots in Colorado during surveys conducted in 1966-1969 by Braun and Rodgers (1971), in the San Juan Mountains in 1998-1999 (Larison 2001), an introduced population at Pikes Peak (Hoffman and Giesen 1983), and sites in the Northern Colorado from 1990-1996 (Martin et al. 2000). .................................................................................................................................................... 88 Photo 8. Example of a nest examined during egg counts and a successfully hatched nest ............................................ 100 Photo 9. White-tailed ptarmigan hen with recently hatched chicks ....................................................................................... 102 Table 8. Snow Telemetry (SNOTEL) - Natural Resource Conservation Service (NRCS) National Water and Climate Center data for precipitation near the four study sites examined for reproductive success in Colorado from 20132017. Independence Pass is the closest SNOTEL sites to Independence Pass and Mt. Yale survey sites, Red Mountain is most representative of Ophir, and Slumgullion is closest to Mesa Seco. ...................................................... 107 Photo 10. Example of snow cover at Ophir survey site on 7 June 2016 ................................................................................. 107 Table 9. One hundred and fifteen white-tailed ptarmigan nests and 54 broods were monitored in Colorado at four study sites (Mesa Seco, Independence Pass, Mt. Yale, and Ophir) from 2013-2017. Successful nests were those that at a minimum hatched one egg and a chick left the nest. Successful broods were broods that survived to 49 days. .................................................................................................................................................................................................................. 110 Figure 21. Daily nest survival of white-tailed ptarmigan in Colorado across four survey sites from 2013-2017. 111 Figure 22. Probability of a White-tailed ptarmigan nest surviving a 29 day period. White-tailed ptarmigan lay approximately 1 egg/day, with an average clutch size of 5.45 eggs, incubate between 23 and 26 days, and thus, 11 Page �CPW 2018 White-tailed Ptarmigan spend a minimum of 29 days on a nest. Daily nest survival was modeled as a random intercept model for each year by plot combination around a mean (mu) survival probability and were allowed to increase with the age of the nest. Overall nest survival was derived as the product of daily nest survival among time of hatch and day 1, and every interval through the survival between age 28 and 29. Yellow boxplots represents sites in the North population and red represents those sites surveyed in the South population. .................................................................... 112 White-tailed ptarmigan nest sites found in Colorado 2013-2017 ........................................................................................... 113 Photo11. Female on a nest located in thick alpine avens next to a boulder ........................................................................ 113 Photo 12. Female nesting next to boulders ....................................................................................................................................... 113 Photo 13. Female nesting amongst boulders.................................................................................................................................... 114 Photo 14. Female nesting under common juniper.......................................................................................................................... 114 Photo 15. Female nesting in willows.................................................................................................................................................... 115 Photo 16. Female nesting in open within low stature vegetation ............................................................................................ 115 Photo 17. Female nesting below treeline ........................................................................................................................................... 116 Figure 23. Daily pre-fledging chick survival of white-tailed ptarmigan at four study sites in Colorado from 20132017. ................................................................................................................................................................................................................. 118 Figure 24. Site level estimates of the number of female chicks hatched for every hen of reproductive age at four study sites (two in the North population and two in the South population) in Colorado from 2013-2017. To be included in estimate chicks had to survive from time of hatch to 49 days. .......................................................................... 119 Table 10. Climate change emissions scenarios, the time period for which they were forecast, and the seasons and populations considered in this analysis. ............................................................................................................................................. 129 Table 11. Elevation associated with locations of radio-collared white-tailed ptarmigan in Colorado during the defined summer season (mid-May to November) and in winter (November to mid-May). We recorded 3379 locations of white-tailed ptarmigan from 2013-2017; 2950 locations in the summer and 429 locations in the winter. .............................................................................................................................................................................................................. 130 Table 12. Quantiles (0.025th, 0.25th, 0.5th, 0.75th, and 0.975th) associated with each covariate layer for the locations at which white-tailed ptarmigan were reported. Precipitation values are in centimeters, temperature values are in degrees Celsius, and Topographic Ruggedness Index is a unitless index of terrain ruggedness. All 12 Page �CPW 2018 White-tailed Ptarmigan other values are in meters (land cover class values are for distance to nearest raster cell of that type) or percent cover (percent of raster cell composed of that land cover class). ............................................................................................ 131 Table 13. Species-level model results and covariate 95% credible intervals (with mean posterior covariate estimate, and 2.5% and 97.5% credible intervals, CI) for models using Colorado Gap Analysis Project data. ...... 132 13 Page �CPW 2018 White-tailed Ptarmigan Chapter 1 General Overview The white-tailed ptarmigan (Lagopus leucura) resides in alpine habitats occurring in the western cordilleras from Alaska to New Mexico (Hoffman 2006, Martin 2014, Martin et al. 2015). Colorado supports the most extensive distribution of white-tailed ptarmigan in the lower 48 states due to the state’s high concentration of alpine habitats (Hoffman 2006). Doesken et al. (2003) stated that roughly three quarters of the Nation’s land above 3048 m elevation lies within Colorado. The State has 58 mountains 4267 m or higher, and about 700 peaks above 3962 m (Colorado Geological Survey – coloradogeologicalsurvey.org/Colorado-geology/topography/). Because the Colorado Rockies provide a massive ecoregion of alpine habitat, conservation and assessment of the white-tailed ptarmigan has become a priority for Colorado Parks and Wildlife (CPW). In 2010 the white-tailed ptarmigan was petitioned to be listed as threatened under the Endangered Species Act (ESA). The U.S. Fish and Wildlife Service (USFWS) determined on 5 June 2012 that substantial biological information existed to warrant a 12-month status review for two of the five recognized subspecies of white-tailed ptarmigan: the Mt. Rainier white-tailed ptarmigan (L. l. rainierensis) that occurs in Washington State and the southern white-tailed ptarmigan (L. l. altipetens) which occurs primarily in Colorado with peripheral populations in New Mexico (USFWS 2012). Concern for the species was based on predicted climate change that could directly affect the breeding success and survival of the white-tailed ptarmigan by impacting the health and distribution of alpine and subalpine willow species that are important forage for the species; changing temperatures in winter that could impact snow quality, limiting roost site availability; alterations in summer thunderstorm patterns potentially impacting vegetation and increasing mean daily temperatures; increases in the stochasticity and severity of spring storms that could affect vulnerable chicks and nesting hens; and increases in predation and competition from species 14 Page �CPW 2018 White-tailed Ptarmigan (e.g., dusky grouse - Dendragapus obscures) accessing higher elevations as an upward shift in alpine tolerant species occurs (Martin 2001, Hoffman 2006, Center for Biological Diversity 2010). The 12-month USFWS status review is to be published in 2020 and the information contained in this report will aid in this decision making process. The white-tailed ptarmigan is also a Species of Greatest Conservation need in Colorado’s State Wildlife Action Plan (SWAP; 2015) which cites domestic sheep grazing, recreation, and climate change as the main threats to the species. The SWAP stated that additional monitoring of white-tailed ptarmigan in Colorado is warranted to evaluate responses to changing environmental conditions. Though accessing alpine areas in Colorado and other parts of the white-tailed ptarmigan range can be difficult especially during certain times of the year, an impressive amount of research has been amassed on the species. This work includes monitoring of populations at two long-term study sites at Rocky Mountain National Park and Mt. Evans starting in the late 1960s by Braun (1969) and continuing until today (Wann 2012, 2017), extensive work on describing the ecology (Braun 1969) and behavior of the bird (Schmidt 1969), food selection (May and Braun 1972, Clarke and Johnson 2005), reproductive ecology (Braun and Roger 1971, Giesen and Braun 1979a, 1979b, Giesen et al. 1980, Braun et al. 1993, Wiebe and Martin 1995, 1997, 1998a, 1998b, Martin and Wiebe 2004, Larison 2001, Sandercock et al. 2005a, 2005b, Martin and Wilson 2011, Wann et al. 2016, Wann 2017), winter habitat use (Braun and Schmidt 1971, Giesen and Braun 1992, Braun et al. 1976, Hoffman and Braun 1975, 1977), and research on recruitment and dispersal (Giesen and Braun 1993, Martin et al. 2000). Outside of Colorado, studies have been conducted in southern Yukon Territory, Canada, where the species occurs sympatrically with rock and willow ptarmigan (L. muta and L. lagopus; Wiebe and Martin 1998a, Wilson and Martin 2010). White-tailed ptarmigan have also been studied in Glacier National Park (Choate 1963, Benson and Cummins 2011) and in an introduced population in the Sierra Nevada, California (Clarke 1989, Clarke and Johnson 1990, 1992, Frederick and Gutiérrez 1992). These studies have shown that white-tailed ptarmigan have 15 Page �CPW 2018 White-tailed Ptarmigan exceptional adaptive abilities to survive in extreme environments, with a k-selected life history pattern of low annual fecundity, and adult female survival being vital to maintaining local populations. Population dynamics are thought to be driven by predation, resulting in year-to-year variation in reproductive output and survival. Maintaining connectivity of suitable habitat patches for demographic rescue has been shown to be necessary to sustain populations. The extensive long-term research on the white-tailed ptarmigan has provided an exceptional opportunity to evaluate the current population status of the bird in Colorado. For example, in 2011 statewide occupancy surveys (Seglund 2011) showed that distribution of the species had not changed across the state since earlier mapping of white-tailed ptarmigan occupancy was conducted in 1966-1968 by Braun and Rodgers (1971). The 2011 project was the first step in a contemporary evaluation of the species’ status in Colorado. This current report includes CPW’s work evaluating demographic parameters including estimates of abundance, seasonal and annual survival, and reproductive success. Incorporating spatial and temporal variation in the demographic and abundance rates measured, we developed an Integrated Population Model (IPM) and a Population Viability Analysis (PVA) to provide an overall risk assessment of populations into the future across multiple spatial scales. The IPM and PVA will be useful to inform the Species Status Assessment by the USFWS for the 12-month status review, and to develop conservation strategies at local sites where birds may be enduring differential pressures, as well as across the state where environmental conditions may play a role in overall population viability. Finally, the use of individually radio-marked birds allowed assessment of resource selection during the summer and winter seasons, with spatial patterns evaluated to test the utility of a Predicted Range Model (PRM), and to identify predictor variables to model impacts of climate change on species occurrence. 16 Page �CPW 2018 White-tailed Ptarmigan Taxonomy The white-tailed ptarmigan belongs to the Order Galliformes, Family Phasianidae, and subfamily Tetraoninae. Five subspecies of white-tailed ptarmigan are currently recognized based on a combination of plumage and morphology (Aldrich 1963). The subspecies L.l. luecura occurs in Alaska, Canada, Montana, and the Yukon; L. l. altipetens in Colorado, New Mexico, and Wyoming with introduced populations moved from Colorado to California, New Mexico, and Utah; L. l. rainierensis in Washington state; L. l. peninsularis in Alaska, and L. l. saxatilis occurring on Vancouver Island in British Columbia. CPW, in conjunction with the U.S. Geological Survey, Fort Collins Science Center (USGS), and other partners collaborated to use traditional genetic markers (microsatellites) and a genomic approach (single nucleotide polymorphisms) to evaluate the historic subspecies designation (Langin et al. 2018). This collaborative research found that L. l. altipetens and L. l. saxatilis formed distinct groups that were divergent from each other and from the other three subspecies. This was not surprising as both L. l. altipetens and L. l. saxatilis are geographically isolated from the other purported subspecies (L.l. luecura, L. l. rainierensis, and L. l. peninsularis). In contrast, divergence between the other three subspecies was not as well-defined. Evaluating genetic differences in Colorado, the authors found fine-scale structure was apparent between white-tailed ptarmigan in the San Juan Mountains and those in the central and northern mountain ranges (in the remainder of the document these two population areas will be identified as the South population and North population, respectively). Though there is most likely periodic gene flow between the two populations, it is likely infrequent, resulting in populations remaining relatively isolated from one another. This lack of connectivity between the South population and the remaining alpine habitat to the north and east in the North population is not surprising based on the topography of the state. The nearest suitable alpine habitat to the San Juan Mountains is ~50 km to the Elk Mountain Range. Dispersal distance appears to be limited for the 17 Page �CPW 2018 White-tailed Ptarmigan white-tailed ptarmigan, with the longest distances recorded being from two transplanted males that traveled 43 and 50 km across primarily forested habitat to return to their original breeding site (Braun et al. 1993). Pikes Peak provides a second example of the limitations of dispersal distance. This isolated mountain contains suitable habitat, but no records of white-tailed ptarmigan occupying the area were known until individuals were successfully transplanted there (Hoffman and Giesen 1983). This mountain is >60 km from the nearest occupied habitat, demonstrating the limitations of birds traveling long distances to establish new populations. During this project we recorded movements for a radio-collared female that traveled 46 km from her breeding area to her wintering area and a second female moving 53 km during the winter season; both movements were contained within the San Juan Mountains. Thus, white-tailed ptarmigan can potentially travel the distances between the South population and the Elk, Sawatch or Sangre de Cristo Mountains in the North population, but it is most likely a rare occurrence due to the distance between potential suitable habitat and the lack of stopover alpine patches among the ranges. Measures of genetic diversity were estimated using microsatellite data for all sites where feathers were collected from white-tailed ptarmigan during capture. Allelic richness, which represents an average number of alleles per sampling group and adjusts for discrepancies in samples size by incorporating a rarefaction method was calculated using the FSTAT program (Goudet 2002); expected heterozygosity was calculated using the software diveRsity (Keenan et al. 2013; Table 1). Genetic diversity is an important measure for conservation as it plays a role in the long-term persistence and adaptability of a species (Greenbaum et al. 2014). The expected heterozygosity measured for both the North and South populations in Colorado were similar to other populations of white-tailed ptarmigan (Langin et al. 2018) with the exception of the small remnant populations found in New Mexico and on Vancouver Island in British Columbia, where there is concern of low population numbers and lack of connectivity (Braun and Williams 2015, Jackson et al. 2015). The individual site scale analyses also demonstrated comparable levels of 18 Page �CPW 2018 White-tailed Ptarmigan diversity for the subspecies. The results from isolated locations in Colorado (i.e., Flat Tops and Sangre de Cristo Mountains that are situated 50 km from neighboring alpine habitat) showed lower levels of heterozygosity and allelic richness than sites connected by abundant suitable habitat. Measures of allelic richness at each hierarchical level (statewide, North population vs. South population, and at the individual site) are dependent on the number of samples used in the comparison (i.e., analysis rarefies based on the smallest sample size; Bashalkhanov et al. 2009). Because we were only able to collect five samples at some locations, our sample size to evaluate allelic richness at the individual site level was low. Nevertheless, patterns were similar between the measures of allelic richness and expected heterozygosity that uses all samples collected from a population (i.e., not a subsample). Continued monitoring and further evaluation of these isolated areas is warranted to ensure they maintain viable populations in the face of climate change and increased disturbance. The measured genetic diversity in the North and South populations in Colorado indicates that there is adequate gene flow to maintain high genetic diversity, with currently no evidence of severe effects of small population sizes or deleterious effects of inbreeding. Changes are expected to occur across white-tailed ptarmigan habitat in Colorado due to anthropogenic influences and climate change, thus conservation actions should be focused at preservation of the current genetic structure and movement of alleles to ensure the species is able to adapt and survive future environmental modifications. 19 Page �CPW 2018 White-tailed Ptarmigan Table 1. Measures of genetic diversity for Colorado, for the South population (San Juan Mountains) and the North population (all other mountain ranges in the state), and for each individual site where feathers and blood were collected from captured white-tailed ptarmigan. Columns show sample size (n), rarefied allelic richnes, and expected heterozygosity. Statistics were calculated using the FSTAT program. At the population and individual site level for allelic richness, the FSTAT program uses the smallest sample size to subsample and if there are missing data at a locus, a sample is not incorporated. This is why the sample was four in the individual site analysis and 93 for the population analysis. n 224 Allelic Richness 7.74 n 248 Expected Heterozygosity 0.73 North population 93 6.99 153 0.72 Byers Peak Flat Tops Independence Pass Mt. Evans Mt. Yale Rocky Mountain National Park Sangre de Cristos 4 4 4 4 4 4 4 3.75 2.82 3.89 3.69 3.86 3.75 2.97 16 5 29 25 25 29 5 0.68 0.47 0.66 0.64 0.65 0.61 0.54 South population 93 6.9 95 0.7 Emerald Lake Mesa Seco Ophir Southern San Juan Mountains 4 4 4 4 3.7 3.57 3.58 3.71 29 36 25 5 0.65 0.63 0.62 0.61 Site Colorado 20 Page �CPW 2018 White-tailed Ptarmigan White-tailed Ptarmigan Natural History The white-tailed ptarmigan completes both breeding and nesting activities above treeline in the alpine biome which begins at around 3500 m in Colorado (Braun 1980, Hoffman 2006, Martin et al. 2015). The alpine breeding areas used by white-tailed ptarmigan are characterized by steep, rocky terrain that provides a structurally complex environment with fine-scaled microrefugia, persistent snow fields, short statured vegetation, intense ultraviolet radiation, extreme weather, and brief growing seasons (Martin 2001, Jackson et al. 2015). Breeding in the alpine exposes white-tailed ptarmigan to challenges not faced by avian species using lower elevations for reproductive efforts (Martin 2014). High elevation breeders have less time to breed and thus produce fewer offspring than congeners inhabiting lower elevation sites (Martin et al. 2009, Camfield et al. 2010). Because white-tailed ptarmigan require snow-free areas to initiate nesting; snow depth and persistence can impact the already condensed breeding season faced by this species. Their response to this harsh environment is increased plasticity and alteration of life history traits to favor adult survival over high reproductive output (Morton 1976, 2002, Martin and Wiebe 2004, Sandercock et al. 2005a, 2005b, Bears et al. 2009, Martin el al. 2009, Lu et al. 2010, Martin 2014). This lowered reproductive output is apparent in clutch size with the white-tailed ptarmigan laying the smallest average clutch size (Braun et al. 1993, Martin et al. 2015) of any North American Tetraonidae with the exception of the spruce grouse (Falcipennis Canadensis; Johnsgard 1973, Schroeder et al. 2018). There is however, within species variation with white-tailed ptarmigan at higher latitudes in the Yukon having larger average clutch sizes, higher fecundity, and lowered adult survival (Wilson and Martin 2011, Martin et al. 2015). White-tailed ptarmigan have also been found to have a longer incubation period making them potentially more prone to nest predation and decreasing their ability to renest if a first nest is lost. With their ability to raise only one brood per season, and with precocial chicks highly susceptible to predation, white-tailed ptarmigan maintain strong dependency on adult survival when compared to other grouse such as the willow ptarmigan that breed at higher 21 Page �CPW 2018 White-tailed Ptarmigan latitudes, but lower elevations (Martin et al. 1993, Wiebe and Martin 1998a, Sandercock et al. 2005a, 2005b, Wilson and Martin 2011). Because white-tailed ptarmigan have low reproductive success and annual fecundity that is highly variable, it is thought that connectivity among alpine sites is imperative to maintain viable and genetically diverse populations (Martin 2014). White-tailed ptarmigan are predominantly a monogamous species with males arriving to set up breeding territories prior to females (Schmidt 1969, Braun 1984, Hoffman 2006). Both females and males attempt to breed in their first year, though dominant adult males may occupy prime territories, leaving some males to defend marginal sites without securing a mate (Hoffman 2006). Unpaired females are rarely if ever encountered (Wiebe and Martin 1998a). Males are very vocal during territorial establishment and will actively defend territories from other males (Schmidt 1969, Braun and Roger 1971, Hoffman 2006). Pairs stay together during the nesting stage, but only the female incubates; males remain close and are vigilant for predators and other males in the area (Wiebe and Martin 1997, Martin 2014). Females are capable of renesting if their first nest fails early in the season (females will not renest if a brood is lost) and accordingly males will remain close to the female during nesting to ensure they maintain their pair bond for additional breeding opportunities if they arise. Incubation periods for white-tailed ptarmigan vary from 22-24 days with average nest survival measured at Mt. Evans to be 0.24 (0.19-0.30; Martin et al. 2015). Fecundity rates (hatched young/per female) also measured at Mt. Evans from 1987-1996 averaged 1.77 (1.57-1.97; Martin et al. 2015). After hatching precocial young, the male normally leaves the female to join up with other males or unsuccessful females. The female alone raises chicks though some females with chicks will forage together at common brooding areas and can be in very close proximity (Hoffman 2006). Females will adopt chicks (Braun and Rogers 1971). Adoption rates for white-tailed ptarmigan on Vancouver Island, British Colombia were found to be 13% and the Ruby Ranges, Yukon Territory 4% (Wong et al. 2009). During our surveys we observed instances of adoption with hens having 22 Page �CPW 2018 White-tailed Ptarmigan different aged chicks in the same brood; some hens caring for as many as 12 chicks; hens living in close proximity and sharing care of young chicks; and observations of females during the actual adoption phase of an abandoned or separated chick. White-tailed ptarmigan hens normally brood their chicks until they are one to three weeks old (Pedersen and Steen 1979). During the first few weeks of life, chicks are unable to maintain normal body temperature and need to interrupt feeding bouts with maternal brooding (Theberge and West 1973, Allen et al. 1977). White-tailed ptarmigan chicks are capable of flight at 10-12 days of age at which time survival of young increases (Martin et al. 2015). By early September, birds can be found in large flocks of >30 birds that consist of males, females, and juvenile birds (Hoffman 2006). At this time, deciphering distinct females with chicks for accurate brood counts is not possible (Braun and Rogers 1971). White-tailed ptarmigan remain gregarious in fall and winter until the breeding season is initiated in spring (Hoffman 2006). Hoffman and Braun (1977) reported that birds arrive at wintering areas sometime in October or November depending on snow depth, and remain there until they depart for breeding sites sometime mid-April to May depending on timing of spring snow melt. Flock composition on wintering areas is not static and numbers fluctuate; probably in response to weather and snow conditions. Flocks are usually partially sexually segregated, with males wintering closer to breeding areas than females (Hoffman and Braun 1977, Hoffman 2006). White-tailed ptarmigan appear to have high site fidelity to wintering areas and return to the same areas each year (Giesen and Braun 1992). However, Martin et al. (2000) suggested that white-tailed ptarmigan will migrate shorter distances during mild winters when food resources are more easily accessible. Suitable wintering habitats may be limiting for white-tailed ptarmigan (Hoffman and Braun 1975, Braun et al. 1976, Herzog 1980, Hoffman 2006) as a consequence of extreme weather and high snowfall limiting access to willow for foraging and increases of anthropogenic disturbances in montane and subalpine areas (e.g., ski areas, reservoir construction, roads etc.; Braun et al. 1976, 23 Page �CPW 2018 White-tailed Ptarmigan Giesen and Braun 1992). Winter home ranges are larger for females than males, who remain close to breeding areas (Hoffman and Braun 1975). Females also travel greater distances to wintering areas from breeding areas, with the longest recorded movement (prior to our study) being 22.7 km (Hoffman and Braun 1975, Giesen and Braun 1992). 24 Page �CPW 2018 White-tailed Ptarmigan Chapter 2 Threats Assessment Climate Change Climate is far from static and it has changed throughout the planet’s long history, but today the change is occurring at an extraordinary rate and driven by human activities that have increased atmospheric concentrations of greenhouse gases (Lukas et al. 2014). Average temperatures at the earth’s surface have increased by 1.6°F since 1900 and 0.8°F since 1980 with increases in storm severity and frequency (Easterling et al. 2000, Carey 2009, Intergovernmental Panel on Climate Change 2013). Colorado over the last 30 years has experienced rising temperatures of >2°F, resulting in the state warming more rapidly than the U.S. average (National Conference of State Legislatures 2008, Colorado State Forest Service at CSU 2018). This warming has been measured using Snow Telemetry (SNOTEL) data from the Natural Resource Conservation Service (NRCS) National Water and Climate Center which measures mean daily temperatures. Since 1985, mean daily temperature during June, July, and August near our study sites has risen with measures in June steadily increasing > 5°F over the past three decades (Figure 1). The projected climate for the state is a continuation of this warming trend with mid-century annual statewide temperatures increasing by an average of 5° to 6° F (National Conference of State Legislatures 2008, Lukas et al. 2014). Alpine ecosystems are extremely susceptible to warming as temperatures proceed at a disproportionately rapid rate at high elevations (Grimm et al. 2013). In addition, ozone concentrations are elevated and increased CO2 concentrations can impact growth rates and abundance of plant species in alpine ecosystems (Martin 2014). Unlike temperature, precipitation patterns are highly variable and projections for moisture changes are uncertain. However, nearly all 25 Page �CPW 2018 White-tailed Ptarmigan projections predict an increase in winter precipitation by 2050 (National Conference of State Legislatures 2008, Lukas et al. 2014, Colorado State Forest Service, Colorado State University 2018). Even with an increase in winter precipitation, earlier spring snowmelt is predicted due to rising temperatures, dust on snow events, and increases in airborne toxins, synergistically impacting spring snowpack and reducing late summer stream flows. These projected changes will exacerbate the warmer summers that could result in severe droughts and increases in wildfires (Lukas et al. 2014). Currently, Colorado snowpack appears to be less vulnerable to earlier snowmelt and lower winter snow levels than other western mountain ranges (Mote et al. 2005). Colorado’s expansive high elevation habitat remains cold with temperatures below freezing and snowpack levels more stable (Stewart et al. 2005, Mote et al. 2005). Inouye et al. (2000) found that spring temperatures have warmed over a 25 year period (1975-1999) at the Rocky Mountain Biological Laboratory near Gothic, CO (elevation 2945 m); however, the average melt off date had not changed as a result of enhanced snowpack at the highest elevations. The disappearance of winter snowpack is the primary determinant of the growing season in the alpine, thus Inouye et al. (2000) concluded that climate change had not yet impacted plant phenology at the highest elevations. Clow (2009) found that from 1978-2007, snowmelt runoff was occurring earlier in the year in the mountains of Colorado. The Climate Change in Colorado Report (Lukas et al. 2014) predicts an increase in winter precipitation, but this increase will be mediated by higher temperatures. Though climate change will continue to impact high elevation habitats in Colorado, it is expected that the most vulnerable places are at lower elevations where the climate is temperate and no alpine habitat occurs (Krajick 2004). At lower elevations earlier snowmelt has resulted in longer growing seasons, earlier migrations of birds, and earlier breeding of certain taxa resulting in shifts in phenologies (Inouye et al. 2000, Parmesan and Yohe 2003). 26 Page �CPW 2018 White-tailed Ptarmigan The alpine life zone in Colorado begins at around 3500 m, encompassing short statured herbaceous vegetation above the treeline. The weather in the alpine is harsh and consists of short growing seasons, long winters, low atmospheric pressure, high winds, and afternoon summer thunderstorms that keep mean daily temperatures low. This life zone is characterized by extreme topography and spatial variability that influences snow deposition and produces an array of microhabitats for plant communities. The alpine is not contiguous but naturally fragmented as a consequence of topography, and isolated high elevation mountains have been referred to as “sky islands” (Powledge 2003). Climate change can affect the alpine life zone with the rapid infusion of atmospheric pollution (Carbon dioxide, Nitrogen, and acid rain), warming temperatures, intensified weather events, and changes in precipitation and snow cover (Körner 2003, Martin 2014). These changes could impact alpine vegetation, soils, phenological adaptations, and could cause these vertical “sky islands” to become smaller and more fragmented if treeline expands upslope (Dirnböck et al. 2003, 2011, Hickling et al. 2006, Cannone et al. 2007, Illerbrun and Roland 2011, Grimm et al. 2013, Tingley and Beissinger 2013). In addition, other taxonomic groups could begin to migrate upslope to higher elevations in response to climate warming, increasing predation risk and competition for the white-tailed ptarmigan (Dirnböck et al. 2003, 2011, Hickling et al. 2006, Cannone et al. 2007, Illerbrun and Roland 2011, Grimm et al. 2013). Diaz and Eischeid (2007) found that because of rising temperatures the climactic type of the alpine tundra in the western United States has been reduced by 73%. However, other monitoring efforts have found that the alpine has remained relatively intact over the last 150 years and continues to be dominated by native species (Kiilsgaard 1999 in Martin 2014). It has been suggested that the white-tailed ptarmigan can serve as an indicator to the health of alpine ecosystems (Jackson et al. 2015). Research investigating potential impacts of climate change on white-tailed ptarmigan has documented median hatch dates as much as 15 days earlier due to warmer spring temperatures (Wang et al. 2002, Wann et al. 2016). The long-term consequences of 27 Page �CPW 2018 White-tailed Ptarmigan earlier breeding is a potential extension of the reproductive period, allowing more time to renest if a first nest attempt fails, thus increasing the potential reproductive output of a hen. It could also provide potential benefits to spring body condition as willow forage to build fat reserves is abundant earlier in the season. Conversely, earlier nesting could result in young chicks being exposed to unpredictable spring storms, mismatches in phenology of food availability reducing the quantity and quality of the food, increased competition by species moving upslope to breed, and an increase in predator activity (Walther et al. 2002, Diaz and Eischeid 2007, Jackson et al. 2015, Wann 2017, 2018 et al. in press). However, both Wang et al. (2002) and Wann et al. (2016) did not find evidence that earlier nesting in response to increases in spring temperatures negatively impacted white-tailed ptarmigan reproductive success. Wang et al. (2002) suggested that warmer winter maximum and minimum monthly temperatures may retard population growth rates of the whitetailed ptarmigan population in Rocky Mountain National Park, but they did not provide an explanation for this predicted reduction. Benson and Cummins (2011) found that white-tailed ptarmigan at Glacier National Park have changed their distribution by moving upslope a distance of 335 m, altered their use of habitats, and experienced a local population decline as a consequence of increases in temperature and a reduction in persistent snow. Modeling future climate scenarios on current measured habitat use of the Vancouver Island white-tailed ptarmigan indicated increased fragmentation and reduction in suitable summer resource areas, with consequences predicted to be reduced fecundity and survival (Jackson et al. 2015). It has been stated by several authors that moving forward in the face of climate change, it will be important to manage and maintain connectivity of white-tailed ptarmigan populations for demographic rescue and to preserve genetic diversity for conservation over the long-term (Martin 2001). 28 Page �CPW 2018 White-tailed Ptarmigan Figure 1. Average daily temperatures for summer months (June-August) recorded at Snow Telemetry (SNOTEL) - Natural Resource Conservation Service (NRCS) National Water and Climate Center data near three survey sites in Colorado. Mean temperature began to be recorded at all sites in the mid-1980s. The Independence Pass SNOTEL site is the closest station to the Independence Pass and Mt. Yale survey sites. Red Mountain is close to the Ophir survey site and Slumgullion is closest to the Mesa Seco survey site. Date were collected at survey sites from 2013-2017. 60 Mean Monthly Temperature °F 50 40 30 20 10 0 June July August Red Mountain June July August Independence Pass June July August Slumgullion Pass 1986-1990 44 48 46 44 47 47 45 47 47 2000-2005 47 50 48 46 52 48 47 52 48 2013-2017 49 50 48 49 52 49 52 53 50 29 Page �CPW 2018 White-tailed Ptarmigan Grazing by Domestic Livestock Sheep grazing in Colorado was established around the 1880s and was unregulated prior to the establishment of the USDA Forest Service (USFS) and the Department of the Interior Bureau of Land Management (BLM) (Colorado Wool Growers Association, USDA 2014). The number of sheep in the state peaked in 1886 with an estimated 2 million animals (History of Agriculture in Colorado 1926). Due to limited access to the high country except in summer, sheep generally grazed alpine areas in early July until mid-September. Unregulated sheep grazing that allowed large numbers of animals on the landscape, resulted in alteration of alpine forage and left many areas used for regular bedding denuded and trampled. Observations prior to 1903 noted that sheep left definite routes throughout alpine areas and caused damage to existing trails due to the widening and erosion of soils (DuBois 1903). In 1917 the USFS began regulating sheep grazing on public forest lands and by 1940, sheep numbers allowed on the National Forests had been reduced to about 250,000; today about 34,000 are permitted on National Forest lands in the Gunnison, Uncompahgre, San Juan, and Grand Mesa National Forests (Bradford et al. no date given, USDA 2014). In the 760-square-mile Weminuche Wilderness, there are six active grazing allotments with 5600 permitted sheep (Romeo 2017). In addition to a reduction in the total number of sheep, the public land agencies also implemented management recommendations aimed at sustainable grazing (Bradford et al. no date given). These changes included dividing the sheep range into allotments and assigning these to permittees with designated numbers of sheep and season of use. Today sheep can only graze an area from 1-10 days depending on forage conditions, and cannot return to the same area to graze in one season. The average band of sheep allowed to graze as a herd ranges from 2500-3000 animals; this includes both ewes and lambs. The herder is required to move sheep every few nights to reduce impacts of overuse of bedding sites. Sheep are also now managed to graze in an open fashion to help disperse 30 Page �CPW 2018 White-tailed Ptarmigan them across the landscape and reduce trampling and overgrazing. Permittees are required to meet with rangeland specialists on an annual basis to evaluate and alter grazing plans as needed. Though the number of sheep grazing in the alpine has steadily declined and management has improved since it became a practice in the west, concentrated sheep grazing and trailing in the alpine remains a concern. Wet areas are susceptible to trampling and drier sites have high erosion potential (Fleischner 1994). Sheep consume some of the plant species important for white-tailed ptarmigan such as willow and alpine buttercup (Ranunculus adoneus; May and Braun 1972) and plant species composition can be altered by domestic livestock grazing (Bonham 1971, Fleischner 1994). Bonham (1971) found that more species of palatable forbs occurred in ungrazed alpine meadows versus sheep grazed meadows. Western yarrow (Achillea lanulosa) was the most widely distributed species in grazed areas whereas marsh marigold (Caltha leptosepala), American bistort (Polygonum bistortoides), and alpine avens (Geum rossii) were more abundant on ungrazed sites. Alpine avens and bistorts are important forage species for white-tailed ptarmigan, comprising >30% of the diet (Clarke and Johnson 2005). Domestic sheep are often in the alpine during the brood rearing season of white-tailed ptarmigan and can cause separation and disruption of hen and chicks when chicks are young and vulnerable (Taylor Peltier, personal observation July 2016). Hunting The number of hunters engaged in harvesting white-tailed ptarmigan in the state is low due to limited access to areas and pursuit of a species with minimal reward (i.e., meat) for the effort required. Most hunters are interested in pursuing white-tailed ptarmigan to complete their list of hunted upland game species or as a novelty hunt. The primary concern regarding hunting in the state is that the easily accessible alpine areas such as those found at Mt. Evans, Independence Pass, Byers Peak, Crown Point, and Guanella Pass, receive most of the pressure. Because hunting takes place in the fall (September – November), birds are congregated in flocks and thus when a hunter encounters a flock, it is generally possible for them to harvest their daily bag limit (Daily Bag Limit 31 Page �CPW 2018 White-tailed Ptarmigan = 3, Possession Limit = 6; 2018 CPW Small Game and Waterfowl Brochure). Wann (2017) documented negative implications of hunting on populations at Mt. Evans, with extinction probabilities amplified and population growth rates reduced. However, hunting most likely has little state-wide population level impact. Mining The mountains in Colorado were formed by tectonic plates colliding and volcanic activity that created rich mineral deposits that attracted miners to the state starting in the late 1800s (Colorado Encyclopedia - https://coloradoencyclopedia.org/). These early miners left everlasting scars in the mountains as a result of excavating tunnels over 900 m deep and 8 km long in search of gold, copper, lead, zinc, and silver (Henderson 1926). The majority of mining occurred in an area defined as the Colorado Mineral Belt where ore deposits span from the La Plata Mountains in Southwestern Colorado to the Front Range near Boulder (Chapin 2012; Figure 2). Though this area contains naturally occurring metals in the soil and surface water, historic mining activity led to toxic mine tailings being dumped into rivers, large waste piles of unusable mined materials left on the surface, and thousands of abandoned mines dotting the landscape (Colorado Geologic Survey http://coloradogeologicalsurvey.org/mineral-resources/, The Interstate Technology and Regulatory Council Mining Waste Team (ITRC; 2008). Acid mine drainage resulting from seepage into abandoned mine shafts and erosion of mine waste has contaminated ground and surface watercourses with heavy metals negatively impacting plants, wildlife, aquatic species, and human water users downstream (Larison 2001, Macingova and Luptakova 2012, Handwerk 2015). Prior to 1977, laws did not exist that required mines be reclaimed after mining activities were terminated or mine disturbances mitigated. Today, the Colorado Division of Reclamation Mining and Safety is responsible for assuring that these mined lands are restored; however, this is currently nearly an impossible task as according to the ITRC “the sheer numbers of sites requiring attention in Colorado is overwhelming”. In Colorado there are an estimated 23,000 abandoned 32 Page �CPW 2018 White-tailed Ptarmigan mines with many assumed to be leaking toxic materials laced with cadmium, aluminum, lead, copper, and zinc resulting in 1645 miles of streams within 25 watersheds being impacted (Colorado Department of Public Health and Environment -https://www.colorado.gov/pacific/cdphe/wqmining). Long-term exposure to this acidic mine waste on humans has been found to have health effects ranging from mental health issues, cancer, and kidney disease (Simate and Ndlovu 2014). In addition, exposure can have negative impacts on aquatic life, stunt terrestrial plant growth, and harm wetlands. Most experts agree that the impacts due to mining in the state are likely to persist for centuries to come. Research has been conducted on the effects of cadmium, a metal mined in Colorado’s high country, on white-tailed ptarmigan (Larison 2001). Willow, essential forage for the species (May and Braun 1972), has been shown to biomagnify cadmium and willow carrs downstream of abandoned mines have regular uptake of cadmium. Larison (2001) found that current cadmium levels in the San Juan Mountains were toxic to white-tailed ptarmigan with 46% of the adult birds tested having kidney-cadmium thresholds above toxic level and lowered bone calcium levels. The cadmium-affected white-tailed ptarmigan had reduced fitness, smaller average clutch sizes, and lower reproductive rates compared to baseline populations outside of the Colorado Mineral Belt. Larison (2001) postulated that without immigration into these cadmium-impacted populations, localized extinction would occur. This study concluded that cadmium exposure is a concern for white-tailed ptarmigan inhabiting areas in the Mineral Belt of Colorado. Nonetheless, white-tailed ptarmigan continue to occur across the mineral belt almost 150 years after mining became a prominent resource extraction in Colorado’s alpine habitats. 33 Page �CPW 2018 White-tailed Ptarmigan Figure 2. Active mining claim records intersected with the southern white-tailed ptarmigan predicted range model for Colorado. 34 Page �CPW 2018 White-tailed Ptarmigan Recreation The human population has expanded from four billion in 1974 to over seven billion in 2017 with a projected increase to eight billion by 2025 (U.S. Census Bureau; World POPClock projection https://www.census.gov/popclock/). The United States population was estimated at 327,542,690 as of April 2018, with the 2017 population in Colorado being 5,607,154; an 11.5% increase since 2010. The increase in the population has not only meant more infrastructure, pollution, and habitat modification, but increased use of outdoor recreation sites by hikers, mountain bikers, off highway vehicles, snowmobiles, snow bikes, and skiers. The magnitude of human impact changes has been extreme and has occurred at a very rapid rate (Milligan et al. 2009). The environmental stressors (e.g., negative impacts to vegetation by overuse and lack of management, noise and air pollution, disturbing white-tailed ptarmigan in preferred use areas, extra trash etc.) produced by an increase in use of the alpine could impact the fitness, survival, and reproductive success of white-tailed ptarmigan. Popular and increasingly used hiking trails and all terrain vehicle (ATV) roads can often become deeply incised without proper maintenance and drainage. These incised recreational trails and roads capture and trap water from rain and snowmelt runoff which leads to improper flow patterns, accelerated erosion, dewatering and drying out of meadows, wetlands, fens, and willow carrs all which can occur down slope of these trails and roads. Lack of management and maintenance of these roads and trails can potentially impact suitability of winter and breeding areas for white-tailed ptarmigan. Snowmobiles, snow bikes, and recreational skiing can have negative impacts for white-tailed ptarmigan, including flushing of the species from preferred feeding, roosting or loafing areas, and causing them to expend extra energy when reserves may be low due to extreme temperatures and snow cover (Hoffman 2006, Martin 2014). Additional negative impacts for white-tailed ptarmigan by snowmobiles are compaction of snow and crushing of willows, affecting winter food resources, 35 Page �CPW 2018 White-tailed Ptarmigan and depletion of winter snow roost availability. Increases in the popularity of winter recreational activities may also attract and provide mammalian predators easier access to higher elevations by making available travel corridors along snowmobile and ski trails (Martin 2014). Recreation in both winter and summer in the alpine and subalpine has dramatically increased in many areas, particularly those that are easily accessible. Increased visitation can lead to more trash, trampling of sensitive areas in the alpine, unattended dogs harassing white-tailed ptarmigan adults and chicks, and disruption caused by noise pollution. Updating and instituting regulations such as camping restrictions, education on disposing of human trash and waste, and enforcement of existing regulations are warranted in many areas. 36 Page �CPW 2018 White-tailed Ptarmigan Chapter 3 Population Dynamics Introduction An essential task for wildlife conservation and management of species at risk is having the ability to accurately assess population dynamics and determine how populations will respond to current and projected environmental changes. Complicating this mission is defining and evaluating populations across multiple spatial scales. To understand factors impacting wildlife populations, knowledge about abundance and vital rates including annual survival, immigration, emigration, and reproductive output are required. Estimating species-specific demographic parameters across multiple spatial scales from a site or community level perspective to a regional landscape is extremely difficult, nevertheless it is needed to inform the most advantageous conservation strategies and guide Species Status Assessments for USFWS (Coates et al. 2018). Most surveys to estimate these parameters are generally only practical when conducted on a small, localized spatial scale due to the focus needed to obtain sufficient data to inform model predictions (McCaffery and Lukacs 2016). In order to upscale localized estimates to produce state and range-wide assessments, multiple randomly selected survey sites need to be incorporated into model parameters. Capture-mark-recapture surveys (CMR) have been advocated as a means to assess populations by providing precise estimates of abundance and survival for species of concern based on recapture rates of uniquely marked individuals (Sandercock 2006, Clifton and Krementz 2006). The merging of CMR data into a Robust design framework can further reduce biases in estimates caused by heterogeneity in recapture probabilities by accounting for temporary emigration to unobservable states (Kendall and Nichols 1995, Kendall et al. 1995, 1997, Sandercock 2006, Kendall et al. 2009, Sanders and Trost 2013). In addition, developing a model that integrates telemetry and CMR data 37 Page �CPW 2018 White-tailed Ptarmigan may increase accuracy and precision in population assessments and identify vital rates most influential to population changes (Johnson et al. 2010). We used intensive CMR methods in conjunction with a Robust design to evaluate population dynamics of the white-tailed ptarmigan at six survey sites (three in the North population and three in the South population). In addition we radio-collared individuals at each site to inform assumptions associated with our models (i.e., closure). The objectives of our surveys were to estimate age-specific site fidelity, abundance, apparent survival, and true survival. Using CMR abundance estimates in addition to vital rate information collected from radio-collared birds, we developed an IPM. IPMs have become a popular tool to evaluate the current health of populations (Kéry and Schaub 2012). Because we were not only concerned with defining the current state of the population, we used the IPM to inform a PVA to predict future viability of the population of whitetailed ptarmigan in Colorado and within the North and South population areas. Intersecting population patterns with a threats assessment we considered potential management and conservation strategies needed to ensure persistence. Study Areas Prior to our study, CPW had developed a PRM for white-tailed ptarmigan (Figure 3; CPW GIS 2006). This PRM incorporated areas > 3292 m in elevation and Colorado Gap Analysis Project (COGAP; Schrupp et al. 2000) vegetation types that included Mixed Tundra, Meadow Tundra, Prostrate Shrub Tundra, Bare Ground Tundra, Exposed Rock, Shrub Dominated Wetland/Riparian, and Graminoid/Forb Dominated Wetland. The PRM for summer habitat for white-tailed ptarmigan encompassed 7584 km2 or 2.8% of the state, with the dominant land manager being the USFS and 55% of the predicted range designated as USFS wilderness. In 2011, the first efforts were initiated by CPW to assess the distribution of white-tailed ptarmigan in the state (Seglund 2011). The primary parameter of interest for the project was the number of occupied plots within the white-tailed ptarmigan range. The PRM was used as the 38 Page �CPW 2018 White-tailed Ptarmigan sampling frame from which to select a population of 60 plots (5.5 x 4.6 km) to conduct occupancy surveys. Only plots that contained a minimum of 50% suitable habitat within their boundaries based on the PRM were selected for sampling. No other selection criteria were required so plots occurred in the middle of wilderness areas and in extremely steep, difficult to access terrain. Expanding the 2011 surveys to look more intensively at demographic parameters at smaller spatial scales, we randomly selected four plots (plot names are based on the associated quad map where site occurs) for the intensive CMR surveys. We also selected two sites (Mesa Seco and Independence Pass) intensively studied from 1966-1969 by Braun and Rogers (1971) (Figures 4-9) to be included in the CMR surveys. The six sites were evenly divided between the defined North and South populations based on fine-scale genetic structure (see Taxonomy for description of genetic differences). The South population exclusively contains the San Juan Mountains and the North population consists of all other mountain ranges where white-tailed ptarmigan occur in Colorado. Based on long term weather station data, the North population has been shown to receive more consistent winter snowfall and less consistent summer moisture and conversely, the San Juan Mountains making up the South population have less dependable winter moisture, but more reliable summer precipitation. The three survey sites in the North population included: Byers Peak, located north of Interstate 70 in the Arapaho National Forest outside of Empire, Colorado along the Front Range of the Rocky Mountains; Independence Pass, which is located midway between the towns of Aspen and Twin Lakes along the Continental Divide in the Sawatch Range; and Mt. Yale, located in the Collegiate Peak Wilderness west of Buena Vista. The three sites surveyed in the South population included Mesa Seco near Lake City; Ophir west of Silverton; and Emerald Lake in the Weminuche Wilderness. The six sites surveyed varied in topography, snow accumulation, weather patterns, wind velocity, hunting pressure, and disturbance levels. 39 Page �CPW 2018 White-tailed Ptarmigan Figure 3. Overview map of capture-mark-recapture survey locations sampled in 2013-2016 for whitetailed ptarmigan in Colorado and for breeding propensity, nest, and chick survival surveys from 20132017. Sites are overlaid on the Predicted Range Model for the species with three sites located in the North population and three sites in the South population defined by fine-scale genetic structure. 40 Page �CPW 2018 White-tailed Ptarmigan Figure 4. Byers Peak survey site for capture-mark-recapture surveys conducted in Colorado for whitetailed ptarmigan from 2013-2016. Surveys were conducted within the red polygon during the breeding, brood rearing, and fall primary periods. Survey boundaries were adjusted for the 2014 and 2015 breeding surveys due to heavy snow cover that caused areas of the site to be inaccessible. 41 Page �CPW 2018 White-tailed Ptarmigan Photo 1. Byers Peak – This site is characterized by steep, extremely rocky terrain with remnant snow fields persisting throughout most of the summer. This site has high unrelenting winds that made capture difficult at times due to safety considerations for the bird. Disturbance in the summer and fall in this area included hikers and big game hunters. In winter, snowmobiling and skiing occur at lower elevations around the site that may impact willow habitat. This population of white-tailed ptarmigan is hunted due to easy access in summer and fall by a 4-wheel drive road and proximity to the large human population areas along the Front Range. 42 Page �CPW 2018 White-tailed Ptarmigan Figure 5. Emerald Lake survey site where capture-mark-recapture surveys were conducted from 20132016 in Colorado for white-tailed ptarmigan during the breeding, brood rearing, and fall primary periods. 43 Page �CPW 2018 White-tailed Ptarmigan Photo 2. Emerald Lake – This site is in the middle of the Weminuche Wilderness and is difficult to access. It has very steep topography and remnant snow fields persist throughout most of the summer. The area is dotted with lakes and moist microsites. Disturbance is relegated to backpackers who mainly stay on designated trails around Rock Lake, the largest lake in the survey site. Hunting of white-tailed ptarmigan and winter recreation do not occur due to remoteness of the site. 44 Page �CPW 2018 White-tailed Ptarmigan Figure 6. Independence Pass survey site for capture-mark-recapture surveys conducted in Colorado for white-tailed ptarmigan from 2013-2016. Surveys were conducted within the red polygon during the brood rearing, and fall primary periods. Survey boundaries were adjusted for the 2014 and 2015 breeding surveys due to heavy snow cover that caused some areas of the site to be inaccessible. Breeding propensity, nest, and chick survival were evaluated at this site from 2014-2017. 45 Page �CPW 2018 White-tailed Ptarmigan Photo 3. Independence Pass- This site has steep topography and remnant snow fields that persist throughout the summer. Colorado State Highway 82 divides this survey site. This is an extremely popular road travelled by tourists to access the high country. However, most people stay along the road or designated trails. In spring after the road is open on Memorial Day weekend, skiing is popular and many backcountry enthusiasts use the area. Dogs frequent the area with their owners and many are allowed off leash to run free. Hunting for white-tailed ptarmigan occurs here due to easy access by the highway. 46 Page �CPW 2018 White-tailed Ptarmigan Figure 7. Mesa Seco sample area for capture-mark-recapture surveys conducted in Colorado for whitetailed ptarmigan from 2013-2016. Surveys were conducted within the red polygon during the breeding, brood rearing, and fall primary periods. Survey boundaries were adjusted for the 2014 and 2015 breeding surveys due to heavy snow cover making some areas of the site inaccessible. Breeding propensity, nest, and chick survival evaluated at this site from 2013-2017. 47 Page �CPW 2018 White-tailed Ptarmigan Photo 4. Mesa Seco – As the name suggests this is a dry mountain with snow only persisting in very high snow pack years and no lakes occurring at the study site. This site is a relatively flat mountain with little topographic relief. A 2-track road allows access to the area, but use is limited from July-October due to closures to protect elk (Cervus canadensis) calving and winter range. Sheep grazing occurs in the area in July with the timing impacting brood rearing. No reports of harvested white-tailed ptarmigan have been reported and winter recreation is limited due to the dirt road leading to the trailhead to access the area being closed by the USFS in late fall. 48 Page �CPW 2018 White-tailed Ptarmigan Figure 8. Mt. Yale sample area for capture-mark-recapture surveys conducted in Colorado for whitetailed ptarmigan from 2013-2016. Surveys were conducted within the red polygon during the breeding, brood rearing, and fall primary periods. Survey boundaries were adjusted for the 2014 and 2015 breeding surveys due to heavy snow cover the cause areas of the site to be inaccessible. Breeding propensity, nest, and chick survival evaluated at this site from 2013-2017. 49 Page �CPW 2018 White-tailed Ptarmigan Photo. 5. Mt. Yale – This site has steep topography and remnant snow fields persist throughout most of the summer. It is located in designated Wilderness. Small perennial lakes dot the landscape. The site is near the 4267 m peaks of Mt. Yale and Mt. Harvard – both are extremely popular destinations for climbers. It is also near Kroenke Lake which is a popular spot for recreationists. Most people who visit the area stay on established trails. No hunting of white-tailed ptarmigan has been reported for this area and no winter recreation occurs due to its remoteness. 50 Page �CPW 2018 White-tailed Ptarmigan Figure 9. Ophir sample area for capture-mark-recapture surveys conducted in Colorado for white-tailed ptarmigan from 2013-2016. Surveys were conducted within the red polygon during the breeding, brood rearing, and fall primary periods. Survey boundaries were adjusted for the 2014 and 2015 breeding surveys due to heavy snow cover causing some areas of the site to be inaccessible. Breeding propensity, nest, and chick survival evaluated at this site from 2013-2017. 51 Page �CPW 2018 White-tailed Ptarmigan Photo 6. Ophir – This site is west of Silverton and has become a very popular destination for day hikers and backpackers. It has steep topography and remnant snow fields persist most of the summer. The area contains numerous lakes and abundant mesic vegetation. Recreationists visiting the area commonly wander off established trails increasing disturbance in the alpine. Biking and climbing of peaks has become popular in the basin and the many dogs that accompany their owners to the area are allowed to roam freely. No hunting of white-tailed ptarmigan has been reported. 52 Page �CPW 2018 White-tailed Ptarmigan Field Methods Photo 7. Uniquely number banded female white-tailed ptarmigan with attached radio-collar To locate white-tailed ptarmigan at our six survey sites, territorial male calls were played using FOXPRO digital game units to increase detection rates. Males will readily respond to territorial male calls by responding with their own call or flying to the source of the suspected intruder (Braun et al. 1973). Males will respond to playbacks from May to late August, though responses decline after females start incubating. In late August through September when males are congregating in flocks, eliciting a response with playbacks becomes difficult. We used chick calls during the brood rearing season to attract female birds to observers. Playbacks of chicks have been shown to double the number of detections of females with chicks or for those that have recently lost chicks (Braun et al. 1973). Females will respond to chick distress calls by making a warning cluck, making themselves visible by standing up and coming into the 53 Page �CPW 2018 White-tailed Ptarmigan open or by investigating the call source by moving towards it (Braun et al. 1973). Females readily respond to playbacks from mid-July to late August when chicks range from two to seven weeks of age. Suitable habitats were surveyed within each of the six survey sites based on previous research showing areas used by white-tailed ptarmigan include alpine with the presence of willows, rocky or talus areas, dry ridge tops, moist alpine meadows, and snow fields (Choate 1963, Braun and Rodgers 1971, Frederick and Gutierrez 1992, Hoffman 2006). A noose pole was used to capture individual birds (Zwickel and Bendell 1967; modified for white-tailed ptarmigan by Braun and Rogers 1971). Each captured bird was weighed, aged as subadult or adult based on the presence of pigmentation on the 9th and 10th primary feathers (Braun and Rodgers 1967), marked with unique colored/numbered leg bands to identify individuals during encounter surveys, and feather and blood samples were collected for genetic and genomic analyses (Langin et al. 2018). We captured only subadult and adult birds; females with young chicks were not captured and marked to reduce disturbance and potential loss of chicks. Chicks were also not captured or banded. A portion of birds captured at each study site were fit with RI-2D 9.3 g VHF radio transmitters with a mortality switch (Holohil Systems LTD. Ontario, Canada). Collar battery life was normally 15-16 months so individual birds could be followed through completion of two breeding seasons. CMR surveys (termed secondary occasions) were conducted within defined primary periods to estimate abundance, site fidelity, and survival. Secondary occasions were designed to be spaced close enough in time to maintain the assumption of closure (i.e., no immigration, emigration or mortality), however, intervals between primary periods allowed for the population to be open to estimate apparent survival, temporary emigration, and immigration back to the sampling site (Figure 10). Assumption of closure was informed by following radio-collared birds during secondary occasions. 54 Page �CPW 2018 White-tailed Ptarmigan The four primary periods selected for sampling were in the breeding, brood rearing, fall, and winter seasons. The breeding primary period began at the end of May when the snow begins to melt in the alpine and birds return from wintering areas to their breeding territories. In general, we expected relatively high detection rates during this period owing to males being readily responsive to electronic playbacks as they defend territories (Braun et al. 1973). The breeding primary period lasted until mid-June when females began to incubate eggs. The brood rearing primary period was designed to follow immediately after nests hatched and females would be actively raising chicks (late July to late August). During brood rearing, females responded to playbacks imitating chick distress calls and detection rates remained relatively high. The fall primary period began in late August and lasted until October when white-tailed ptarmigan began to form flocks and move to ridgelines (Braun and Rogers 1971). During fall, birds were less likely to respond to playbacks, though once birds were detected, they were usually assembled into large flocks. The last season considered was the winter primary period when birds move to preferred wintering areas (Hoffman and Braun 1975). Estimating abundance within and survival between each primary period considered, was essential to help direct management and conservation towards the most critical times of the year and demographic age class. Primary periods for breeding, brood rearing, and fall contained a minimum of three and maximum of five secondary sampling occasions. Given the constraints of sampling in the Colorado alpine, all winter sampling was done via aerial telemetry surveys for radio-collared birds from a fixed wing airplane. The detection of birds was high with the use of aerial telemetry but the method costly; therefore only one secondary occasion for each of the winter primary periods was completed and thus abundance estimates during this primary period could not be determined. During each secondary occasion, observers used a Garmin GPS unit to collect tracks to define their daily CMR route. Tracks were downloaded into ArcGIS and a 100 m buffer (the distance estimated that playbacks could call a bird in) was drawn around the outer most survey route to 55 Page �CPW 2018 White-tailed Ptarmigan define the area sampled. Study site boundaries were refined from the 2011 occupancy survey plots to limit encounter efforts to specific basins and surrounding ridgelines that could be surveyed within a single day (Table 2; Figures 4-9). A secondary occasion therefore, was complete coverage of a study site boundary during a CMR sampling effort. Crews attempted to complete a secondary occasion within a single day, but inclement weather at times precluded this from happening. If weather interfered with our ability to complete a survey, crews returned the following morning to where the survey was ended the previous day, and reinitiated the survey. Crews remained in the field until a minimum of three or maximum of five secondary CMR surveys were completed. CMR surveys were conducted by two observers in 2013, but based on preliminary analyses (Seglund and Street 2013), the number of observers was increased to three or four surveyors per site from 2014-2016 to improve the probability of detecting birds. When white-tailed ptarmigan were detected during a survey effort, a total count of white-tailed ptarmigan observed, band combinations, and sex were recorded prior to additional trapping and banding occurring. We attempted to capture all unbanded adult birds encountered during secondary occasions, with the exception of hens with chicks. Many times however, we were only able to capture a portion of the unbanded birds encountered. This was because some birds immediately flew when encountered; some ran to an area that made capture unsafe for the field technician and/or bird; or approaching weather caused capture operations to be aborted and upon returning to an area, birds were no longer present. Birds encountered that were previously banded were not recaptured, but were identified by their unique band combination or numbered band. The incorporation of radio-collared white-tailed ptarmigan into the study design helped evaluate the assumption of closure for our model parameters. Radio-collared white-tailed ptarmigan were located daily during each secondary occasion survey by an observer dedicated to telemetry and independent of the CMR data collection. Telemetry locations were predominantly visual observations of birds unless the bird location was inaccessible and then we resorted to 56 Page �CPW 2018 White-tailed Ptarmigan triangulation to obtain a UTM coordinate. Inaccessibility occurred most often in early spring when snow conditions limited access to some areas of the site. Monitoring of radio-collared birds also informed appropriate timing to conduct primary period surveys to adequately measure populations during the correct defined season (i.e., we did not conduct brood rearing surveys until all radio-collared females were off of nests). 57 Page �CPW 2018 White-tailed Ptarmigan Figure 10. Robust design was used in combination with Huggins closed capture model to estimate abundance of white-tailed ptarmigan for each primary occasion ( ). For each time interval between primary occasions, the Robust design model estimates apparent survival ( ), a combination of true survival and permanent emigration (note that we used estimates from true survival from telemetry data alone in our analysis and ignore the apparent survival estimated here). Temporary immigration was also estimated. is the probability that a white-tailed ptarmigan detected during time interval , but is unavailable for detection ( survived in primary period because it has left the study plot. is the probability that an individual that was not on the study plot and unavailable for detection during primary period primary period remains off of the study plot and is unavailable for detection during Within each primary period there are secondary occasions. 58 Page �CPW 2018 White-tailed Ptarmigan Table 2. Total area surveyed for capture-mark-recapture surveys at six survey sites during three seasons for white-tailed ptarmigan in Colorado from 2013-2016. Only a survey during the brood rearing primary period was completed in 2016. CMR Byers Peak Independence Pass Mt. Yale Ophir Mesa Seco Emerald Lake Km2 Surveyed 2013 All Primary Periods 4.48 3.34 5.22 3.66 3.94 2.39 Km2 Surveyed 2014-2016 Brood Rearing and Fall Km2 Surveyed Breeding 2014 Km2 Surveyed Breeding 2015 4.48 5.02 5.22 3.66 3.94 2.39 1.38 3.22 1.70 2.01 1.93 2.39 2.43 3.13 1.61 2.31 2.96 2.39 59 Page �CPW 2018 White-tailed Ptarmigan Analysis Abundance A Robust design was used in combination with Huggins closed capture model (Huggins 1991) to estimate abundance for three primary periods (breeding, brood rearing, and fall) that could be converted to a density estimate based on area surveyed. This conversion allowed us to compare our estimates to earlier survey efforts conducted. For each time interval occasions between primary , the Robust design estimated apparent survival ( ), a combination of true survival and permanent emigration, as well as temporary emigration . is the probability that a white-tailed ptarmigan survived time interval , but is unavailable for detection ( in primary period because it left the study site, given that it was detected in primary period is the probability that an individual that was not on the study plot and unavailable for detection during primary period primary period remained off of the study plot and was unavailable for detection during Within each primary period there are secondary occasions. The probability that an individual is captured at least once during primary period is calculated as . To rank the fit of each model, an information-theoretic approach based on an Akaike Information Criterion adjusted for small sample size was used (AICc ; Burnham and Anderson 2002). Data analyses were conducted in Program MARK (White and Burnham 1999). Detection was allowed to vary by the type of mark the individual received (those containing a radio telemetry unit versus color banded birds). Each plot was considered as a categorical covariate with survival and temporary emigration concomitantly estimated for both radio-collared and non radio-collared white-tailed ptarmigan. 60 Page �CPW 2018 White-tailed Ptarmigan Integrated Population Model We were most interested in extrapolating an abundance estimate for the state based on the season with the most consistent and least variable survey effort, and to estimate trends in abundance over time. Based on the results from 2013-2015, we completed an additional CMR survey for 2016 during the brood rearing primary period only. We chose this period because logistics of completing the survey were the most feasible due to lack of snow cover, birds maintained high detection rates, they exhibited minimal movements during this primary period and met the assumption of closure, and it allowed for the most complete comparisons among all years of our project. We integrated the CMR data during the brood rearing season with vital rates from radio -collared birds to assess population change from 2013 to 2016 (Kéry and Schaub 2012). For each site surveyed, we assessed how abundance changed from year-to-year. Estimates of abundance were informed by counts of marked and unmarked individuals corrected for detection from CMR data as well as detailed demographic data gained through intensive radio telemetry: where survey effort is the number of secondary occasions completed during a primary survey on each study site. Detection probability (p) was estimated from data collected from encounters of uniquely banded individuals augmented with 500 pseudo individuals per study site by year combination. These individuals were never captured and were treated with a 0 encounter history. Detection was allowed to vary for each site (s) by year (t) combination, but not allowed to vary for each day of the survey. We estimated an inclusion probability (Ω) for the augmented individuals to determine how many individuals were present on the plot but never encountered during a survey as: 61 Page �CPW 2018 White-tailed Ptarmigan where encounter represents the encounter history for each marked individual. A 1 indicated the individual was detected and a 0 if it was not. An additional benefit for conducting the abundance surveys for adult and subadult birds during the brood rearing period was it allowed us to obtain counts of chicks on each survey site. If a hen responded to a chick distress playback, we knew that she potentially had chicks with her and thus, we counted the total number of chicks associated with a detected hen. The counts (C) were on done on each survey site (s), for each year 2013-2016 (t) and each secondary sampling occasion. Because we realized that we may not be detecting all chicks present on a survey site during the brood rearing primary period, we corrected our counts by estimating a detection probability There were insufficient data to estimate a site-by-year-by-study site specific detection rate, but we were able to estimate a separate detection rate for each year (t). Thus the number of chicks on each site during each year was estimated as: Given that we only began marking birds in 2012 during a pilot study (Seglund and Street 2013), there was little prior information to help inform the abundance estimates of adults, or chicks for the 2013 survey year. However, for each year after 2013, the number of adults, and chicks was informed by CMR surveys and demographic processes estimated from the radio-collared birds. The demographic estimates were put into a post birth pulse matrix projection model to help inform the abundance estimate in the following year for each site (Caswell 2001): 62 Page �CPW 2018 White-tailed Ptarmigan where F is fecundity (assumed to be the same for both age classes because subadults can breed), Nchick represents the number of chicks hatched in each site and year combination, and Schick is survival of chicks from hatch to the following breeding season. Sadult is annual survival of adults that are at least one year of age at the beginning of the breeding season. Adult survival was calculated directly from radio-collared white-tailed ptarmigan data; chick survival was calculated as the product of two months of fledgling survival from counts of chicks associated with radio-collared females and 10 months of adult survival. We model monthly adult female survival (MFS) with a nest survival model within the IPM. Each individual bird (i) received an encounter history (y) at a monthly interval (t). Each site (s) had its own unique intercept (α). Time variation was modeled as a seasonal effect with winter, breeding, chick rearing, and fall as additive effects: The number of adults and chicks were scaled up as: 63 Page �CPW 2018 White-tailed Ptarmigan A white-tailed ptarmigan female can only successfully produce a single brood of chicks per season either with her first nesting attempt or second nesting attempt. We defined fecundity (F) in each year (t) at each study plot (s) as: with components of reproduction as described above and the 0.5 to adjust for a 50:50 ratio of females to males at birth. Below we address each component of fecundity as though it were a separate model for simplicity of manuscript. However, each component was written into the same likelihood. The model was fit in Bayesian framework using program JAGS in R, with 100,000 Markov Chain Monte Carlo iterations with three chains and a burnin period of 90,000. Estimation of each parameter was assessed by R-hat statistics and visual inspection of the trace of each chain. Population Viability Analysis We used the IPM to generate parameters for a PVA to assess the risk of white-tailed ptarmigan going extinct in the future at the state level and North and South population level. To guarantee convergence for our model, we ran three chains of 315,000 iterations each, with 300,000 burn-in iterations, and thinning the trace by two. Individual iterations produced a collection of 66 estimates for the PVA, one for each of the 66 parameters of interest (see below). This resulted in the monitoring of 15,000 different estimates for each parameter. The basic population model used to track the simulated populations was a female-only, ‘postbirth pulse’ projection matrix (Caswell 2001): 64 Page �CPW 2018 White-tailed Ptarmigan where Nchick is number of chicks, Nadult is number of adults, F is fecundity as described above (assumed to be the same for both stage classes because subadults can breed), Schick is annual survival of chicks, and Sadult is annual survival of adults, t is the current year time step, and t+1 is the one year forward time step. As described above, adult (true) survival was calculated directly from birds that were radio-collared; chick survival was calculated as the product of two months of fledgling survival and 10 months of adult survival. Total parameters tracked and used in the PVA was 66, with 11 at each study area including three years of estimates for Schick, Sadult, and F, and one estimate each for Nchick and Nadullt. We simulated N = 15,000 (see below) permutations at each of the six survey sites, with three sites representing the North population and the three remaining sites representing the South population. We initiated the population simulations with estimates of chick and adult abundance from each survey site in the fourth year of the study (2016). We multiplied these abundances by the population projection matrix depicted above for 100 time steps in each simulation. If simulated populations at a site fell below two individuals, that area was assumed extinct. We assumed a carrying capacity of 200 individuals per km2. If simulated populations rose above this level they were re-set to 200 individuals per km2 at that survey site. At each time step we extrapolated the sum of the three site abundances to the entire regional population (i.e., North and South populations). The expansion factor (i.e., the ratio of the total population area to the sum area of the three survey sites) was 324.01 km2 for the North population and 281.72 km2 for the South population. If the resulting simulated abundance for the population was zero, then the population was considered extinct for the remainder of the 100 year simulation. As described above, the IPM analysis allowed us to estimate four years of abundance, but we could use only three years of data for the vital rates (e.g., survival and fecundity). To account for 65 Page �CPW 2018 White-tailed Ptarmigan temporal stochasticity in the PVA, at each time step we randomly selected one of the three annual population projection matrices depicted above that were estimated for each population. Parametric uncertainty in the PVA (McGowan et. al. 2011) was incorporated by running a simulation for each of the 15,000 iterations of estimates produced by the IPM analysis. To account for statistical covariance in the estimates, we did not ‘mix’ parameter estimates from different iterations. Accurate projections of populations should incorporate the four primary processes of population dynamics: birth, immigration, death, and emigration (Williams et al. 2002). We were able to track three of these: survival and emigration with radio-collar data, and birth through the estimation of various reproductive parameters. We were unable to estimate immigration. For the PVA (and for the IPM generating estimates for the PVA), we simulated varying levels of densitydependent immigration with the following equation: Number of immigrants = (abundance) (eimm x abundance) where abundance was the current level of abundance in the population simulation at the survey site, e is Euler’s mathematical constant, and imm was a parameter that was varied as we tested different levels of immigration in the PVA. Levels of imm tested were -0.05, -0.07, and -0.2 (Figure 11). With 15,000 combinations of statistical estimates generating 15,000 population simulations for each population, we binned 150 sets of 100 simulations thus obtaining 150 estimates of extinction probability for each population. The 2.5th and 97.5th quantiles of the 150 estimates were used to define a 95% credibility interval on extinction probability. As can be inferred from the description of the IPM above, some parameters shared data and thus estimates across survey sites, populations, and years due to sample size limitations. Breeding 66 Page �CPW 2018 White-tailed Ptarmigan propensity, clutch size, and re-nesting probability were estimated the same for each survey site and year. Chick survival and detection probability for chick abundance were calculated with a mean for all years and a random effect specifically estimating each year (i.e., there was no study site or population-level effects estimated for chick survival or detection probability for abundance). Nest survival and detection probability for adult abundance were modeled with a mean for all sites and year, but with a random effect parameter differently estimating each site and each year. Adult female survival was estimated independently for each site and each year. Ideally, every parameter would have been estimated independently for each survey site-year combination, but we lacked the sample size to do so. 67 Page �CPW 2018 White-tailed Ptarmigan Figure 11. Three levels of immigration that were investigated in the Population Viability Analysis. Base function was number of immigrants = (abundance) (eimm * abundance). Number of immigrants is on the y- Number of indiviuals immigrating axis, abundance is on the x-axis, different levels of imm are represented by the different lines. 8 7 6 5 4 imm = -0.05 3 imm = -0.07 imm = -0.2 2 1 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 Number of individuals in study area before immigration event 68 Page �CPW 2018 White-tailed Ptarmigan Results From 2013 to 2016 we captured and banded 637 individual white-tailed ptarmigan (263 females, 363 males, and 11 unknowns). Adult males made up the largest segment of the population captured (33%; n=207), followed by subadult females (24%; n=154), subadult males (24%; n=153), and adult females (17%; n=108). One hundred and twenty-six white-tailed ptarmigan were fit with VHF radio transmitters to help inform survival and emigration parameters. Of the 126 radiocollared birds, 92 were females (42 subadult and 50 adult) and 34 were males (11 subadult and 23 adult). A total of 3379 telemetry locations were recorded during all seasons of the year. Summer locations were collected from mid-May to November and included breeding, brood rearing, and fall locations. We collected 2950 telemetry locations during this time period from 2013-2017. We collected 429 telemetry locations in winter using aerial surveys one time per month from November until May. Of the total locations collected across seasons, 74% were from females and 26% from males. Abundance Abundance estimates for the three defined seasons (breeding, brood rearing, and fall) were derived with a Robust design with constrained estimates of detection probability to be constant across all sites and years (Table 3). By following radio-collared birds, we found that we were able to meet the assumption of closure within our surveys by 100%. The abundance estimates were converted to densities (bird/km2) based on area surveyed per season (Table 2). 69 Page �CPW 2018 White-tailed Ptarmigan Table 3. White-tailed ptarmigan density estimates (bird/km2) with associated 95% confidence intervals for six study sites for adult and subadult birds, per season, and per year in Colorado from 2013-2015 (2016 was not included in analysis as only a brood rearing season was conducted that year). Some sites were not accessible in late spring to conduct breeding surveys consequently surveys were not conducted (NC). Abundance estimates were derived from the Robust design analysis. Detection probability was constrained to remain constant across all plots and all occasions. Biologically, white-tailed ptarmigan behave differently during survey periods and conditions for surveys can vary. Survey Site Byers Peak Independence Pass Mt. Yale Ophir Mesa Seco Emerald Lake Byers Peak Independence Pass Mt. Yale Ophir Mesa Seco Emerald Lake Breeding NC NC 1.5 (1.3-2.5) 2.7 (2.4-4.1) 7.1 (6.3 -8.6) NC 2014 Breeding 3.6 (2.8-6.5) 5.3 (4.7-7.5) 2.9 (2.4-5.3) 4.8 (4.0-8.0) 8.8 (8.2-11.9) 2.1 (1.7-3.8) 2013 Brood Rearing 6 (5.1-8.2) 5.7 (4.8-7.8) 5.7 (4.8-7.7) 18.6 (15.6-23.5) 6.3 (5.8-8.1) 12.5 (10.9-15.9) Fall 5.3 (4.5-7.3) 7.2 (6.0-9.9) 2.2 (2.1-3.6) 11.2 (9.6-14.2) 15.2 (14.2-17.3) 18.8 (16.7-22.6) Brood Rearing 4.5 (4.0-5.6) 5.6 (5.0-6.8) 4.5 (4.0-6.7) 8.5 (7.6-10.4) 10.2 (9.4-12.2) 15.9 (5.6-18.8) Fall 3.8 (3.6-5.1) 3.4 (3.2-4.6) 3.8 (3.4-4.8) 7.1 (6.6-9.0) 15.6 (14.7-18.0) 8.4 (7.5-10.5) Brood Rearing 6.3 (5.6-7.6) 6.8 (6.0-8.4) 3.4 (3.3-4.6) 6.3 (5.7-7.9) 11.2 (10.4-13.4) 10.5 (9.2-13.4) Fall 7.4 (6.9-8.9) 4.6 (4.2-5.8) 5.7 (4.8-7.7) 10.7 (9.8-12.6) 14.5 (13.4-16.7) NC 2015 Byers Peak Independence Pass Mt. Yale Ophir Mesa Seco Emerald Lake Breeding 2.1 (1.6-3.7) 5.4 (5.1-7.4) 3.7 (3.1-6.2) 3.5 (3.0-5.6) 5.9 (5.6-8.2) 2.5 (2.1-4.6) 70 Page �CPW 2018 White-tailed Ptarmigan Integrated Population Model Unlike the Robust design analysis above that constrained detection to be constant across site and year combinations, detection was allowed to vary for each site and year combination. This was possible because we were only evaluating the changes in the brood rearing period and sampling was more consistent during this period. The model estimated daily encounter rates to range from 0.079 at the Ophir site in 2013 to 0.57 at the Emerald Lake site in 2015. The probability that an individual was detected at least once during a five day secondary occasion survey ranged from 0.23 at the Ophir site in 2013 to 0.98 at the Independence pass site in 2016. Abundance estimates (included adults and chicks) for the state ranged from a high in 2013 of 221,555 birds (CI = 178,615-268,548) to a low of 147,798 (CI = 128,289-171,563) birds in 2014 (Table 4; Figure 12). Abundance estimates at localized survey sites for adults were lowest at the Mt. Yale site in 2014, estimated at 24 birds (SE=5), and highest at the Ophir site in 2013, estimated at 85 birds (SE=18, Figure 13). Chick abundance appeared to be stable at most sites with some variability (Figure 14). 71 Page �CPW 2018 White-tailed Ptarmigan Table 4. White-tailed ptarmigan abundance estimates for the entire state of Colorado and for the North and South populations from 2013-2016. Included with estimates are the lower and upper 95% credible intervals. Abundance Estimate 2013 2014 2015 2016 Statewide 221,555 (178,615-268,548) 147,798 (128,289-171,563) 180,143 (154,376-211,462) 170,623 (149,466-196,423) North 121,942 (91,370-156,495) 79,418 (66,097-95,906) 114,478 (95,258-137,703) 92,457 (80,030-107,894) South 97,342 (76,910-120,576) 66,614 (58,578-76,346) 65,819 (57,471-76,064) 76,228 (66,204-88,742) 72 Page �CPW 2018 White-tailed Ptarmigan Figure 12. White-tailed ptarmigan abundance estimates for the entire state of Colorado and for the North and South populations from 2013-2016. Each survey was conducted during the brood rearing season when hens would respond to chick distress playbacks and males would respond to male territorial playback calls. Estimates were obtained from an Integrated Population Model. We found little evidence for a trend over time at either the state level or population level. 73 Page �CPW 2018 White-tailed Ptarmigan Figure 13. Abundance estimates of adult white-tailed ptarmigan from six study sites in Colorado. Each survey was conducted during the brood rearing season when hens would respond to chick distress playbacks and males would respond to male territorial playback calls. Estimates were obtained from an Integrated Population Model. We found little evidence for a trend over time at either the state level or population level, but evidence for a negative trend at the Ophir site. Yellow boxplots represents sites in the North population and red represents those sites surveyed in the South population. 74 Page �CPW 2018 White-tailed Ptarmigan Figure 14. Abundance estimates of white-tailed ptarmigan chicks from six study sites in Colorado. Each survey was conducted during the brood rearing season when hens would respond to chick distress playbacks and the number of chicks with marked and unmarked hens could be counted. Estimates were obtained from an Integrated Population Model. Yellow boxplots represents sites in the North population and red represents those sites surveyed in the South population. 75 Page �CPW 2018 White-tailed Ptarmigan Site Fidelity The mean distance moved from a summer telemetry location to a winter telemetry location based on defined dates was 6.36 km (range 0.026 – 41.05 km) for females and 1.27 (range 0.066 3.85 km) for males. The maximum distance recorded for a female to move within a season based on telemetry locations, was 53.01 km in winter and 46.46 km in summer after a failed breeding attempt. However, most movements in the summer were localized and limited with both females and males remaining close to breeding areas (Table 5). Table 5. Summary of distances moved during two defined seasons: summer (May 15-October 31) and winter (November 1-May 14) by 126 radio-collared white-tailed ptarmigan in Colorado from 2013-2017. Female Summer Winter Male Summer Winter Average Distance Moved in a season (km) Maximum Distance Moved in a season (km) 0.52 6.58 46.46 53.01 0.40 1.29 6.23 9.92 From the Robust design analysis that estimated temporary emigration among our surveys, we found an interaction between sex and minimum age ( ; Figure 14) with subadult females dispersing from sites at higher rates between the breeding and brooding season than adult females or males of any age. While all females had high probabilities of returning to their site of capture before the breeding period, young females were less likely to return than older females. Males had a low probability of transitioning away from a site during or after the breeding season. When transitioning back onto a plot after winter, we observed the higher return rates for older male birds than younger male birds (Figure 15 and 16). 76 Page �CPW 2018 White-tailed Ptarmigan Figure 15. The probability of a white-tailed ptarmigan transitioning off of a survey site between the breeding, and brood rearing period for both males and females in Colorado 2013-2016. When birds were captured, they were either a subadult or an adult. Each adult captured was considered to be a minimum age of two, and only advanced in age if they were detected in multiple years of the study. 0.45 Transition probability 0.40 0.35 0.30 0.25 0.20 males 0.15 females 0.10 0.05 0.00 0 1 2 3 4 5 Minimum age 6 7 8 77 Page �CPW 2018 White-tailed Ptarmigan Figure 16. The probability that a white-tailed ptarmigan will transition back to the site where it was originally captured in Colorado prior to the onset of the breeding season. Since birds have to transition off of a site before they can come back and chicks were not marked, two is the minimum age a bird can Transition probability transition back to the original plot of capture. 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00 males females 0 1 2 3 4 5 Minmum age 6 7 8 78 Page �CPW 2018 White-tailed Ptarmigan Survival Annual survival of female white-tailed ptarmigan regardless of age varied from a high of 0.894 (SE = 0.08) in 2015-2016 at Emerald Lake to a low of 0.269 (SE=0.11) at Independence Pass in 2013-2014 with an average annual survival of 0.644 (CI=0.471-0.807) in Colorado (Figure 17). The South population maintained higher annual survival of females (0.735, CI=0.559-0.886) and yearto-year survival was less variable compared to the North population (0.542, CI=0.374-0.719, Figure 18). Monthly survival estimates were lowest during the breeding and highest in the brood rearing season (Figure 19). 79 Page �CPW 2018 White-tailed Ptarmigan Figure 17. Annual female survival estimates from 2013-2016 for individual survey site locations. Survival estimates are from breeding season to breeding season and estimates are based solely on radio-collared ptarmigan. Yellow boxplots represents sites in the North population and red represents those sites surveyed in the South population 80 Page �CPW 2018 White-tailed Ptarmigan Figure 18. Annual female survival estimates from 2013-2016 for the North and South populations and statewide. Survival estimates are from breeding season to breeding season and estimates are based solely on radio-collared ptarmigan. Yellow boxplots represents the North population and red represents sites surveyed in the South population. 81 Page �CPW 2018 White-tailed Ptarmigan Figure 19. Monthly adult survival modeled as a seasonal effect. May - June were considered to be the breeding period, July - August as brood rearing, September - October as fall, and November-April of the following year as winter. This seasonal effect was modeled with an additive structure with each year population combination. Thus the pattern will be the same regardless of the population or year, but the estimates will be shifted up or down depending on the population and year combination. For simplicity of the figure, we chose to show only the North population in 2013. 82 Page �CPW 2018 White-tailed Ptarmigan Population Viability Model We estimated the North population to have a 25 year median extinction probability of 0.07 (95% CI 0.02-0.21), a 50 year median extinction probability of 0.26 (95% CI 0.08-0.51) and a 100 year median extinction probability of 0.42 (95% CI 0.17-0.70). We estimated the South population to have a 25 year median extinction probability 0.00 (95% CI 0.00-0.01), a 50 year median extinction probability of 0.03 (95% CI 0.00-0.18) and a 100 year median extinction probability of 0.10 (95% CI 0.00-0.33) (Table 6, Figure 20). Statewide extinction probabilities were lower, with a 25 year median extinction probability of 0.00 (95% CI 0.00-0.01), a 50 year median extinction probability of 0.01 (95% CI 0.00-0.07) and a 100 year median extinction probability of 0.04 (95% CI 0.00-0.17) (Table 6). Note that none of the estimates above included immigration in the simulations. When we did include immigration, two of the immigration functions tested in the PVA resulted in extinction estimates of 0.00 (95% CI 0.00-0.00) 100 years into the future for the South, North, and Statewide populations. Very weak immigration (immigration parameter = -0.2) also produced estimates of 0 extinction probability for the South, North, and Statewide populations throughout the 100 year simulations. For the South and Statewide populations the upper 95% CI of extinction probability was 0.0 for all years. For the North population, upper 95% CIs reached 1% after 68 years and 2% after 85 years, staying at 2% until the year 100. 83 Page �CPW 2018 White-tailed Ptarmigan Table 6. Extinction probabilities (and 95% CIs) estimated from a Population Viability Analysis using data from six survey sites across Colorado from 2013-2016 and assuming no immigration. Extinction probabilities were calculated for the entire state, the North and South populations. Extinction Probability 10 years Statewide North South 0.00 (0.00-0.00) 0.00 (0.00–0.01) 0.00 (0.00-0.00) 25 years 0.00 (0.00-0.01) 0.07 (0.02-0.21) 0.00 (0.00-0.04) 50 years 0.01 (0.00–0.07) 0.26 (0.08-0.51) 0.03 (0.00–0.18) 100 years 0.04 (0.00–0.17) 0.42 (0.17-0.70) 0.10 (0.00–0.33) 84 Page �CPW 2018 White-tailed Ptarmigan Figure 20. Projected extinction rates 100 years in the future for white-tailed ptarmigan in Colorado based on a Population Viability Analysis and assuming no immigration. Yellow represents the 95% credibility interval for sites in the North population, red represents the 95% credibility interval for those sites surveyed in the South population and brown is statewide. 85 Page �CPW 2018 White-tailed Ptarmigan Discussion Abundance Abundance is often of interest to wildlife managers, although this parameter can be difficult to estimate accurately. During the design phase of our project, we attempted to develop survey protocols with the rigor necessary to estimate abundance during three biologically meaningful primary periods that also had historic estimates from prior literature for comparison (Braun and Rogers 1971, Hoffman and Giesen 1983, Martin et al. 2000, Larison 2001). The breeding, brood rearing, and fall periods all presented their own logistical challenges when conducting CMR surveys, along with changes in white-tailed ptarmigan behavior and habitat use across a site. For this reason, our models had to be constrained to estimate detection as a constant probability across all sites and primary periods when analyzing the data in a Robust design framework. This constraint may have led to a potential bias in estimates however; we felt that a measure of abundance was much more informative than counts alone and conversion of abundance to a density estimate permitted data comparisons to previous studies. Comparing our estimates of density to past surveys in similar locations, we found limited evidence for biologically meaningful discrepancies in the numbers of animals per unit area. It is worth noting, that different methodologies and analyses were used to derive estimates produced by other authors. In addition, spring snowpack levels and snowmelt timing could impact estimates for the breeding season. For example, we encountered high snowpack levels during breeding surveys from 2014-2016 which limited access to survey sites and hindered our survey efforts. Higher snow levels may also delay arrival of birds to survey sites. Benefits of surveying during high snow levels are that white-tailed ptarmigan become easier to detect as they preferentially use snow-free areas for camouflage during their molt to nuptial plumage. Nevertheless, because white-tailed ptarmigan are a territorial species, we did not suspect that larger numbers of birds would congregate on smaller island areas resulting in higher densities recorded. 86 Page �CPW 2018 White-tailed Ptarmigan Considering all caveats, estimates for breeding densities at Mesa Seco (5.9-8.8 bird/km2) were higher than what was estimated by Braun and Roger (1971) at the same site (5.3-6.2 bird/km2), but lower at Independence Pass where we estimated 5.3-5.4 bird/km2 versus Braun and Rogers (1971) estimate of 6.9-8.3 bird/km2. Fall density estimates demonstrated the same pattern with our estimates higher at Mesa Seco (14.5-15.6 bird/km2) and lower at Independence Pass (3.4-7.2 bird/km2) than estimates in the late 1960s at Mesa Seco (8.6-12.7 bird/km2) and Independence Pass (7.4-14.2 bird/km2; Braun and Rogers 1971). Breeding densities at our Ophir site (2.7-4.8 bird/km2) were lower than were estimated by Larison (2001) in the same general area (7-8 bird/km2; Table 7). 87 Page �CPW 2018 White-tailed Ptarmigan Table 7. Estimated breeding densities (birds/km2) of white-tailed ptarmigan at study plots in Colorado during surveys conducted in 1966-1969 by Braun and Rodgers (1971), in the San Juan Mountains in 1998-1999 (Larison 2001), an introduced population at Pikes Peak (Hoffman and Giesen 1983), and sites in the Northern Colorado from 1990-1996 (Martin et al. 2000). Location Mean Density (range) Birds/km2 Year North Rocky Mountain National Park Mt. Evans Independence Pass Mesa Seco Crown Point Square Tops Guanella Pass Loveland Pass Pikes Peak (Introduced Population) 8.6 (4.3-13.5) 6.3 (2.2-10.3) 7.4 (6.9-8.2) 5.7 (5.3-6.2) 6.6 (5.6-8.2) 3.5 (2.7-4.4) 5.0 (2.1-6.4) 4.7 (4.4-4.8) 6.0 (3.4-8.4) 1966-1969 1966-1969 1966-1969 1966, 1967, 1969 1966-1969 1993-1996 1990-1996 1990-1992 1976-1980 <1 4 7-8 1998-1999 1998-1999 1998-1999 South McMillan Peak Treasure Mountain Ice Lake 88 Page �CPW 2018 White-tailed Ptarmigan Integrated Population Model The IPM allowed us to evaluate the current status of the white-tailed ptarmigan at multiple spatial scales; statewide, population, and the community level scale (defined as the survey site). Having the ability to assess a species across a spectrum of spatial scales is useful in evaluating potential extinction, variation in site potential (i.e., sinks versus source populations), and potential impacts due to differential pressures impacting a species across its range. The statewide assessment provided information on the overall viability of the southern white-tailed ptarmigan and predicted subspecies extinction probability. Evaluating the North and South populations allowed incorporation of community level variability and potential mechanisms of immigration and emigration to maintain a population into the future. Understanding the status of populations and persistence are imperative to evaluate large scale impacts such as climate change. Finally, the community level assessment helped inform threats that may produce negative local impacts to white-tailed ptarmigan and provide managers the ability to develop conservation strategies to mitigate potential disturbances. Because the six individual sites surveyed were not isolated islands that functioned as discrete population areas, but rather locations based on feasibility of completing adequate surveys, we suspect that there is immigration and emigration occurring based on our genetic information. The amount of exchange is currently unknown and probably varies year-toyear and across sites and thus, we were unable to model the impact of this important parameter on abundance at the community level scale. We can say with certainty that we did capture yearling animals every year at sites, but the question remains as to the proportion of these subadults that were born on the site or were recruited from other breeding areas. Of most interest to us, was how abundance estimates changed among years across the state as a whole, for the North and South populations, and at local survey sites. Building off of what we learned from the Robust design, we completed an additional survey in 2016 during the brood rearing period. We chose this period because logistics of completing surveys were the most 89 Page �CPW 2018 White-tailed Ptarmigan practical due to lack of snow cover, detection rates remained high, and birds maintained localized movements. Therefore, this period allowed for the most complete comparisons among all years of our project regarding trends in abundance. At both the statewide and North/South population level analysis, white-tailed ptarmigan populations appear to be stable after an initial decline following our first year of surveys in 2013 (Figure 12). Both 2012 and 2013 saw lower than normal snow pack and in 2013, we encountered high predation rates on nests and chicks (see Chapter 4). The 2014 snow pack was above normal and may have impacted survival of birds with estimates of adult female survival much reduced between 2013 and 2014; especially in the North population. The combination of weather events and predation rates may have caused the dip in abundance in 2014 with an overall uptick in estimates in 2015. Owing to weather and predation rates, annual variation would be expected for an alpine endemic ground nesting grouse that has been shown to have low fecundity and depends predominantly on high adult survival to maintain population viability (e.g., Wilson and Marin 2011, Sandercock et al. 2005a, 2005b, Wann 2017). At the community level of a survey site, we found relative stability in abundance with the one exception being Ophir where we observed declines each year of our survey effort. Observations over the last seven years of annual investigations (surveys began in 2011 for occupancy; Seglund 2011) suggested that increased recreation was pushing white-tailed ptarmigan out of occupied areas. This basin has become extremely popular for a number of activities (e.g., extreme mountain biking on scree slopes and tundra, mountain climbing, fishing, competitive running events, etc.). Though historically, visitors stayed predominantly near the two lakes in the area (Ice Lake and Fueller Lake), additional tourists and popularity of the area have resulted in people traversing into more isolated locations. Each year we found more birds occupying the periphery of the survey site and fewer birds at the commonly used areas when surveys were initiated. This is also the only site where we documented permanent emigration of radio-collared breeding females. Therefore, we 90 Page �CPW 2018 White-tailed Ptarmigan believe in part that the observed declines in abundance may be due to birds leaving the area as a consequence of localized increases in human recreation. Along with steady increases in human recreation during the survey period at this alpine site, abundant snow fell and lingered in the basin each year from 2014-2016. Because of the delayed melt of the snowpack, productivity rates were low potentially due in part to late nesting and no renesting documented. The site did maintain high female adult survival, but emigration and low productivity caused in part by weather resulted in declines in abundance each year of our survey efforts. Independence Pass and Byers Peak appear to have relatively stable populations, but if declines in the future are noted, potential management could be considered to improve community level dynamics. Potential negative impacts at Byers Peak and Independence Pass include hunting pressure (based on hunter band returns) as a consequence of easy access to the sites by vehicle and proximity to large human population centers. Wann (2017) documented negative implications of hunting around Mt. Evans with extinction probabilities amplified and population growth rates reduced at a localized site level. In addition to hunting, recreation at Independence Pass may be of concern. After the highway opens on Memorial Day, skiers annually infiltrate the area to access untracked slopes. The timing of the road opening normally coincides with the prime breeding time for white-tailed ptarmigan. Some skiers bring dogs that are at times, left off leash and seldom under voice control. While conducting surveys we observed dogs chasing and disturbing breeding birds and also documented an unleashed dog killing a white-tailed ptarmigan chick. These disturbances may result in white-tailed ptarmigan moving to other breeding areas or reducing survival of birds that stay. Human traffic in the area may also be an attractant for generalist predators such as red fox (Vulpes vulpes) and common raven (Corvus corax) which are attracted to the trash and food left behind by tourists. The two localized sites that appear to be most stable are Emerald Lake and Mt. Yale. Both Mt. Yale and Emerald Lake occur in wilderness areas where no hunting has been reported to occur, 91 Page �CPW 2018 White-tailed Ptarmigan winter recreation is nearly nonexistent due to their remoteness, and human traffic is limited to backpackers that predominantly restrict their use to trails in the area. Both of these sites also have abundant willow carr and mesic habitats, persistent snowfields, and permanent water. Mesa Seco showed high yearly variation in abundance estimates, but appeared overall stable during the short duration sampled. It is similar to the previous two sites by having limited recreation and hunting, but is different in that it is impacted by annual domestic sheep grazing. It is also one of the driest sites sampled with no permanent water and little to no persistent snow. Mesa Seco does maintain abundant willow habitat and is located near other areas (Cannibal Plateau) that appear to have high densities of white-tailed ptarmigan based on observations during radiotelemetry efforts conducted there. At the community level, various threats are evident across the range of the white-tailed ptarmigan. Understanding the impact of localized disturbances provides options for management when it is warranted to maintain occupancy. An indicator of potential population declines for a monogamous species is an increase in male bias (Hannon and Martin 1992). Braun et al. (1993), reported sex ratios were biased in favor of males due to higher female mortality. We captured 100 more male than female birds during the project, though this could be an artifact of not capturing female hens with chicks. Wann (2017) reported sex ratios of banded birds at Mt. Evans and Rocky Mountain National Park from 19662016 to be 825 females to 888 males. In contrast to our survey, this study did capture and band females with chicks which may have resulted in a more realistic account of sex ratio. Larison (2001) found the ratio of subadult females to subadult males to be a bit higher (52:48) but much lower for adults (38:62). Our ratios were 50:50 for subadults and 34:66 for adults. Thus our populations did not appear to be abnormally biased towards males, and therefore no indication of a population decline based on an abnormal male bias for a monogamous species. Site fidelity was lowest for subadult birds of both sexes at our survey sites with older birds showing high degrees of philopatry. Our findings lend themselves to the idea that outside 92 Page �CPW 2018 White-tailed Ptarmigan recruitment is important to maintaining populations of white-tailed ptarmigan (Martin et al. 2000). Natal and breeding dispersal of white-tailed ptarmigan has been found to be crucial to population connectivity (Martin et al. 2000). Dispersal by the species can occur from brood rearing and natal areas in fall when they move to wintering areas, and in spring when moving from winter sites to breeding areas. We found that female white-tailed ptarmigan moved further between seasonal habitats as well as longer distances within a season than males. This is similar to other studies that found female white-tailed ptarmigan travel greater distances between winter and breeding areas (Hoffman 2006). Based on band returns from birds banded on wintering areas and relocated on breeding sites, the average distance for females to travel was 7.3 km with a maximum distance of 22.7 km whereas males dispersed an average distance of 3.5 km with maximum distance of 10.8 km (Hoffman and Braun 1975). Clarke et al. (1997) found that there is a sex bias in avian dispersal with females more likely to leave a natal area or breeding area and to travel longer distances prior to settling at a site to breed. In Montana, Choate (1963) found that few white-tailed ptarmigan females born on a study site returned to that site the following season. Females have been found to move long distances during the breeding season after a failed nesting attempt (Martin et al. 2000). During our study, we also found radio-collared females occasionally dispersed from their breeding areas after a failed nesting attempt. Some of these females returned to their breeding areas the following season and several moved to new areas pointing to permanent emigration from a site. We found younger males were the least likely to transition back to their original breeding site after winter. This may be because they occupied marginal territories the previous breeding season. During surveys it was not uncommon to observe males defending areas with no female bird concurrently occupying their territory. Studies have found that up to one third of males may be unsuccessful at securing a mate; unpaired females are extremely rare (Choate 1963, Schmidt 1969, Hannon and Martin 1996). Younger males may opt to disperse to other areas to find a higher 93 Page �CPW 2018 White-tailed Ptarmigan quality breeding territory to increase their fitness opportunities (Hoffman 2006). As the males became more established, the propensity to return to breeding areas increased. Our estimates of female annual survival rates are similar to those measured at other locations in Colorado with females having lower survival overall than males (0.44 – 0.61; Martin et al. 2015). The females residing in the South population had higher rates of survival than those in the North population. Why survival was higher in the South population is unknown. White-tailed ptarmigan incurred the greatest mortality rates in May and June. Lower survival estimates in the breeding season were most likely due to birds moving from winter areas to breeding areas and once arriving at breeding grounds; competition by males for mates and females selecting breeding sites increased exposure to predators for both sexes. We observed males being taken by prairie falcons (Falco mexicanus) and golden eagles (Aquila chrysaetos) when preoccupied with defending territories from other males. Other research has also documented that white-tailed ptarmigan are at their most vulnerable during the breeding season (Sandercock 2005a, Wilson and Martin 2011). Population Viability Analysis Predicting population viability into the future includes uncertainty, especially given our limited knowledge about the exact potential condition of Colorado’s high elevation habitats in the face of climate change. However, the PVA has provided us a tool to understand the processes affecting population dynamics and potential data gaps (Gerber and González-Suárez 2010). Statewide the white-tailed ptarmigan population in Colorado appears to be secure with little indication of declining populations and high persistence into the future. The South population was estimated to have a lower extinction rate than the North population. Because we upscaled site survey data to inform our PVA, sites with extremely high or low vital rate values impacted modeled population extinction rates. For example, Emerald Lake was estimated to have very high adult female survival. This site specific vital rate likely contributed to the South population projected extinction rate being reduced, whereas adult survival in the three North population sites was lower as well as more 94 Page �CPW 2018 White-tailed Ptarmigan variable. Other research on white-tailed ptarmigan found that adult survival is the most important vital rate impacting population growth (Martin and Wilson 2011). Because we were only able to investigate six survey sites equally distributed between the North and South populations, and because vital rates can vary site-to-site and year-to-year, our lack of a source site in the North similar to Emerald Lake in the South, may have increased the extinction risk measured for the North population. Overall disturbances in the North population do not appear to be greater than those in the South with the exception of hunting. This activity is more common at locations in the North population area. On the other hand, sheep grazing mainly occurs in the South population. Both the North and South populations have seen increases in recreation and both populations have sites located in the Mineral Belt and thus are impacted by mining. Climate change could potentially have a greater impact in the South due to larger variation in annual snow fall in that part of the state. However, there are too many unknowns associated with current climate change predictions for the alpine in Colorado to adequately model future impacts. Including immigration into the PVA resulted in a 0% estimated extinction probability for all populations, suggesting a rescue effect at even very low levels of immigration. Clearly, more study is needed on movement between suitable habitat patches as it is poorly understood (Martin et al. 2000). Future simulation exercises would be made more valuable by including both high and extremely low immigration rates (i.e., 1% per year below a certain threshold density with stochastic effects such that immigration is zero in some years) to investigate whether slight amounts of immigration affect the probability of persistence. This is important because PVAs based on proportionally small survey sites that don’t include the effects of immigration, are effectively assuming that research areas are islands unreachable by dispersers. This is an unrealistic assumption when small study sites occur in much larger areas of suitable habitat across which dispersal most likely occurs. This may be the reason that previous studies calculating extinction at 95 Page �CPW 2018 White-tailed Ptarmigan site specific scales estimated higher quasi extinction rates as compared to our statewide or population estimates (Sandercock et al. 2005a, Wann 2017). 96 Page �CPW 2018 White-tailed Ptarmigan Chapter 4 Reproductive Output Introduction Extensive work has been done considering the reproductive biology of the white-tailed ptarmigan in Colorado (e.g., Braun and Rogers 1971, Giesen and Braun 1979a, 1993, Larison 2001, Martin and Wiebe 2004, Sandercock et al. 2005a, 2005b, Wann et al. 2016). These projects provided a unique opportunity to compare current results of breeding propensity, daily nest, and chick survival at our study sites with earlier studies before anthropogenic climate change effects became apparent (Intergovernmental Panel on Climate Change 2007) and to more recent studies that have reported earlier laying dates caused by warmer spring temperatures (Wang et al. 2002, Wann et al. 2016). Much of the long-term research on white-tailed ptarmigan in Colorado has been restricted to Rocky Mountain National Park and Mt. Evans with limited short-term studies and information from the San Juan Mountains (Braun and Rogers 1971, Larison 2001, Wann et al. 2016), the Collegiate Mountains (Braun and Rogers 1971), and Pikes Peak regarding an introduced population (Hoffman and Giesen 1983). These areas could potentially differ in reproductive responses due to human disturbance, localized weather, predator communities and associated prey, livestock grazing, topography, hunting, and proximity to mining impacts (i.e., located within the Colorado Mineral Belt). In addition, the North and South populations have been shown to have fine-scale genetic differences (see Taxonomy section above) indicating potential differences in adaptations and survival mechanisms. The objectives of our work were therefore to: 1) assess reproductive success at various sites throughout the state of Colorado where different precipitation patterns/temperatures exist as well as disturbance regimes; 2) compare results to earlier estimates to evaluate potential correlations to increases in temperature and anthropogenic disturbances, and 3) determine important vital rates that could be impacting populations. 97 Page �CPW 2018 White-tailed Ptarmigan Study Sites To evaluate reproductive success we radio-collared females at four of the six survey sites used for CMR surveys: Independence Pass, Mesa Seco, Mt. Yale, and Ophir. Access to Emerald Lake and Byers Peak during the early breeding season was rarely possible due to heavy snow cover each year and high water river crossings. In addition, the intensity that was required to conduct nest and brood monitoring restricted our abilities and limited us to evaluating fewer sites for reproductive success. Field Methods Breeding propensity, nest, and chick survival In 2013, radio-collared hens were monitored every two to four days at Mesa Seco and once every week to two weeks at the other three sites selected to assess reproduction (Independence Pass, Mt, Yale, and Ophir). This was because of limited time and resources for research that year. Beginning in 2014 however, radio-collared female white-tailed ptarmigan were monitored every two to four days at all four survey sites to check the progress of reproduction throughout the incubation periods, and subsequent monitoring of broods through fledgling date (when chicks reached a minimum of 25 days of age; Sandercock et al. 2005a). Collar battery life was normally 1516 months so individual birds could be followed through completion of two breeding seasons. Monitoring involved tracking radio-collared hens to within an observable distance and determining if the bird was on a nest. Once a nest site was discovered, the location and nest substrate were recorded (e.g., next to large boulder, under a willow etc.), a photo of the nest taken, and UTM coordinates collected at the nest so that it could be easily located by the observer conducting the nest follow-up survey. Subsequent checks of the nest were taken from a distance (30 m) to avoid further disturbance to the hen or to inadvertently attract predators. After a female had been documented on a nest for 10 days, she was gently persuaded off her nest to complete an egg count 98 Page �CPW 2018 White-tailed Ptarmigan of her clutch. If during any nest site visit a female was located off of a nest, the nest was revisited to determine the number of eggs hatched, number of unhatched eggs, and number of eggs potentially predated. Female white-tailed ptarmigan eggs hatch synchronously with an even age distribution of chicks that depart a nest six to 12 hours after hatching (Martin et al. 2015). Predation was concluded for nests if the nest was emptied of contents or there were scattered pieces of egg shell (Sandercock et al. 2005a). Hatched eggs were very easy to recognize as they were broken in half with the top of the egg usually flipped inside the bottom half (Photo 8). Nest success was defined as at least one egg hatched and produced a chick that departed the nest. 99 Page �CPW 2018 White-tailed Ptarmigan Photo 8. Example of a nest examined during egg counts and a successfully hatched nest 100 Page �CPW 2018 White-tailed Ptarmigan All females were visually located after leaving a nest to obtain a count of chicks (Photo 9). Brood counts were completed every two to four days. When conducting counts during early brood rearing, observers attempted to locate females in the early mornings when temperatures were low and the females would likely be found brooding chicks. When a radio-collared hen was found brooding, observers would watch the female from a good vantage point and wait until brooding was interrupted with browsing to make an accurate count of chicks. After chicks were able to thermoregulate and no longer required brooding, it was necessary to spend adequate time observing to ensure all chicks were counted as they foraged. Observers again found a good vantage point from which to watch the family group. If the group was found while roosting, the observer waited until the brood and female resumed foraging activities to obtain a count. The observer waited sufficient time to see all chicks get up and move off as sometimes chicks could be quite a distance from the hen and very well camouflaged. If the group was accidentally flushed, counts included chicks flying or running. Female hens with broods can flock together or single females may join with a hen and her chicks. This becomes more common as the season progresses. Deciphering broods when females start mixing with each other can be difficult. If several females were found together with chicks, and broods could not be determined, the observer would quietly walk into the flock and watch how the chicks dispersed and which chicks went with what hen. Counts would be made after the group had separated and began to forage on their own. 101 Page �CPW 2018 White-tailed Ptarmigan Photo 9. White-tailed ptarmigan hen with recently hatched chicks 102 Page �CPW 2018 White-tailed Ptarmigan Analysis Breeding propensity To evaluate the probability a female would breed in a given year, we assigned each female (i) a Bernoulli response ( ) of 1 if she was known to have survived the breeding period and nested or a 0 if she was known to survive and was never detected on a nest. There were not enough data to inform this parameter for each site*year combination, therefore we chose to model this as a constant value. Thus breeding propensity (BP) was modeled as: Similarly, to evaluate a renesting probability, that is if an individual hen was known to have initiated a nest, the first nest failed but she survived and was detected on a second nest, the hen was assigned a binomial response ( ) of 1 or 0 if she did not attempt a second nest after her initial nest failed. A renesting probability was then estimated as: Nest Survival We parameterized our models to estimate daily nest survival (DNS) from the first day that a nest was found until the nest either failed or hatched and had one chick depart. Daily nest survival was modeled as: 103 Page �CPW 2018 where y was 1 if a hen White-tailed Ptarmigan was observed on the nest at time t or 0 if her nest failed. For occasions after the nest was last known to be alive, and before the nest was discovered dead, the encounter history received an Not Applicable (NA) value in JAGS to allow for uncertainty in estimates. This was to account for the time period between nest site visits that were separated by two to four days. Daily nest survival was allowed to vary for each study site j and year y combination around a mean ( ) with a variance . We allowed daily nest survival to increase from the estimated age that the nest was initiated until hatch. The probability that a nest survived from when the first egg was laid until nest hatch (NS) was derived as: Chick Survival Due to low sample sizes, we pooled our study sites to represent the North and South populations, based on genetic structure (see Taxonomy Section). The North population consisted of Mt. Yale and Independence Pass and the South population included Mesa Seco and Ophir. We used an open N-mixture model (Dail and Madsen 2011) to estimate daily survival. We modeled the probability that an individual chick survived and remained with its original hen as Bayesian model framework using counts of chicks the chick . The number of chicks for the first occasion associated with each hen in a and age of was estimated as: where the number of chicks on each subsequent occasion was estimated as: 104 Page �CPW 2018 Detection White-tailed Ptarmigan was modeled as a constant rate across multiple occasions as: where where y is a count of chicks associated with hen . Daily chick survival was allowed to vary for each study site j and year y combination around a mean ( ) with a variance . We allowed survival to increase from the day the eggs hatched until 49 days. The probability that a chick survived from hatch to 49 days (CS) was derived as: Results Breeding propensity We monitored a total of 92 individual female (52 subadults and 40 adults) white-tailed ptarmigan from 2013-2017. Observations of the females during the breeding season resulted in very few nests being located during the egg laying stage; nests were predominantly found once a female was incubating eggs. We found a quadratic relationship of date when modeling the transition from breeding to nesting, with peak nesting occurring around early July. The earliest date a female was found incubating her eggs was on 11 June 2013 at Mesa Seco when there was little snow cover by the end of May (Table 8). In 105 Page �CPW 2018 White-tailed Ptarmigan 2014 and 2016, the first female found incubating was 17 June and in 2017 on 18 June. The latest date a first nest was found was 12 July 2015 at the Ophir site following a heavy snow year with snow melt delayed. The latest date of a renest attempt was 9 July 2015 at the Mt. Yale study site. Hatch dates ranged from 3 July to 4 August with an average hatch date of 18 July for all sites and years. Breeding propensity was estimated to be 0.897 (CI=0.84-0.942) indicating that a majority of females attempted to nest. Of the females that transitioned to nesting and had their first nests fail, 0.14 (CI=0.049) attempted a second nest. Of the six renesting attempts we recorded, four were made by adult birds (66%), and two by subadult females (34%). Renest attempts were recorded at all sites with the exception of Ophir. This site consistently recorded the latest nesting hens due to high annual snow levels and snow lingering for a longer duration as a consequence of the basin being north facing (Table 8; Photo 10). 106 Page �CPW 2018 White-tailed Ptarmigan Table 8. Snow Telemetry (SNOTEL) - Natural Resource Conservation Service (NRCS) National Water and Climate Center data for precipitation near the four study sites examined for reproductive success in Colorado from 2013-2017. Independence Pass is the closest SNOTEL sites to Independence Pass and Mt. Yale survey sites, Red Mountain is most representative of Ophir, and Slumgullion is closest to Mesa Seco. Snow Depth (cm) May 20 2013 2014 2015 2016 2017 Independence Pass 38 68 56 61 33 Red Mountain 35 122 127 135 132 Slumgullion Pass 0 63 63 28 15 Photo 10. Example of snow cover at Ophir survey site on 7 June 2016 107 Page �CPW 2018 White-tailed Ptarmigan Nest survival From 2013 to 2017 we located and monitored 115 individual nests; 60 in the North population and 55 in the South population. Of nests monitored, 65 hatched at least one chick (~57%; Table 9). In the North population 34 nests were successful (~56%) and 31 nests were successful in the South population (~66%). Of the 115 nests monitored, 103 had sufficient data to estimate mean daily nest survival. We found nest survival increased ( = 0.056, SE=0.024) from 0.938 (SE=0.020) when the nest was one day old to 0.987 (SE=0.006, Figure 21) when the nest was 31 days old. The mean probability of a nest surviving until hatch was 0.393 (SE=0.07), and varied from a low of 0.304 (SE=0.121) at Ophir in 2016 to a high at Independence Pass of 0.460 in 2014 (SE=0.142; Figure 22). We did not find evidence for an effect of hen age or nesting attempt on the daily nest survival. The mean number of chicks per brood at hatch was 4.66. All nests monitored that were unsuccessful appeared to fail due to predation. When females were no longer located on a nest, 43 nest checks resulted in the nests being completely emptied with no sign of eggs or shells. Two additional nests that failed also resulted in the death of the female with indications of a mammalian predator due to primary feathers of the female being the only thing not consumed and all eggs absent from the nest. Three nests were found intact with a hen mortality located a close distance from the nest. These three nests appeared to be raptor mortalities as we found plucked feathers under a tree for one hen; a head missing from intact body for another; and a large avian scat at the nest for the final female with her carcass located in an inaccessible cliff. We did find two incidences of nest abandonment by females during the egg laying stage; one nest with one egg, and one nest with three eggs. Both females initiated a new nest after abandoning the initial nest. Potential predators recorded during nest visits included short-tailed (Mustela erminea) and long-tailed weasel (M. frenata), coyote (Canis latrans), red fox, prairie falcon, golden eagle, yellowbellied marmot (Marmota flaviventris), and common raven. 108 Page �CPW 2018 White-tailed Ptarmigan We were able to conduct egg counts at 10-days for 67 nests. The average clutch size for first nesting attempt was 5.46 for all females (range 4-7 eggs per clutch). For second nesting attempts the average clutch size was 4.0 (range 3-5 eggs per clutch). A total of 409 eggs were counted from all nests surveyed from 2013-2017 of which 388 eggs hatched (egg viability ~95%). Unhatched eggs were broken open to inspect contents. All of the eggs inspected with the exception of two, contained only yolk indicating they had not been fertilized or were unviable. Two eggs contained partially developed chicks. White-tailed ptarmigan used various nesting substrates to conceal nests and to provide protection from sun and weather. Placement of nests next to a boulder or boulders was the most common with 51% located near this substrate (Photos 11-13). Nests under willow or other shrubs such as Alpine cinquefoil (Potentilla crantzii) and common juniper (Juniperus communis) were the next most common types of nest cover (34%; Photos 14-15); followed by open ground with low lying stature vegetation (12%; Photo 16), and only a few nests found in or below the krummholz (Picea engelmanni) (3%; Photo 17). 109 Page �CPW 2018 White-tailed Ptarmigan Table 9. One hundred and fifteen white-tailed ptarmigan nests and 54 broods were monitored in Colorado at four study sites (Mesa Seco, Independence Pass, Mt. Yale, and Ophir) from 2013-2017. Successful nests were those that at a minimum hatched one egg and a chick left the nest. Successful broods were broods that survived to 49 days. Year Nests Successful Nests Successful Broods 2013 Adult = 7 Subadult = 7 Adult = 4 Subadult = 6 Adult = 3 Subadult = 1 2014 Adult = 13 Subadult = 7 Adult = 10 Subadult = 3 Adult = 9 Subadult = 2 2015 Adult = 15 Subadult = 10 Adult = 8 Subadult = 6 Adult = 4 Subadult = 3 2016 Adult = 27 Subadult = 14 Adult = 14 Subadult = 6 Adult = 10 Subadult = 5 2017 Adult = 15 Adult = 8 Adult = 3 110 Page �CPW 2018 White-tailed Ptarmigan Figure 21. Daily nest survival of white-tailed ptarmigan in Colorado across four survey sites from 20132017. 111 Page �CPW 2018 White-tailed Ptarmigan Figure 22. Probability of a White-tailed ptarmigan nest surviving a 29 day period. White-tailed ptarmigan lay approximately 1 egg/day, with an average clutch size of 5.45 eggs, incubate between 23 and 26 days, and thus, spend a minimum of 29 days on a nest. Daily nest survival was modeled as a random intercept model for each year by plot combination around a mean (mu) survival probability and were allowed to increase with the age of the nest. Overall nest survival was derived as the product of daily nest survival among time of hatch and day 1, and every interval through the survival between age 28 and 29. Yellow boxplots represents sites in the North population and red represents those sites surveyed in the South population. 112 Page �CPW 2018 White-tailed Ptarmigan White-tailed ptarmigan nest sites found in Colorado 2013-2017 Photo11. Female on a nest located in thick alpine avens next to a boulder Photo 12. Female nesting next to boulders 113 Page �CPW 2018 White-tailed Ptarmigan Photo 13. Female nesting amongst boulders Photo 14. Female nesting under common juniper 114 Page �CPW 2018 White-tailed Ptarmigan Photo 15. Female nesting in willows Photo 16. Female nesting in open within low stature vegetation 115 Page �CPW 2018 White-tailed Ptarmigan Photo 17. Female nesting below treeline 116 Page �CPW 2018 White-tailed Ptarmigan Chick survival Of the 65 nests that hatched, we followed 54 broods (217 chicks) until the chicks reached at least 25 days of age. Detection probability for chick counts was estimated to be 0.690 (SE=0.020). Mean daily chick survival increased ( = 0.069, SE=0.016) from 0.910 (SE=0.020) when the chick was 1 day old to 0.999 (SE=0.001) when the chick was 49 days old (Figure 23). The probability of a chick surviving the entire 49 day pre-fledging period was highest in the North population during 2015 (0.781, SE=0.101), and was lowest in the South population in 2013 (0.047, SE=0.034). Average annual fecundity (female chicks per female at hatch) for all our survey sites and years was 0.995 (CIs = 0.69-1.32; Figure 24). We observed variation among sites and years regarding reproductive output mostly due to impacts of predation. 117 Page �CPW 2018 White-tailed Ptarmigan Figure 23. Daily pre-fledging chick survival of white-tailed ptarmigan at four study sites in Colorado from 2013-2017. 118 Page �CPW 2018 White-tailed Ptarmigan Figure 24. Site level estimates of the number of female chicks hatched for every hen of reproductive age at four study sites (two in the North population and two in the South population) in Colorado from 20132017. To be included in estimate chicks had to survive from time of hatch to 49 days. 119 Page �CPW 2018 White-tailed Ptarmigan Discussion Breeding propensity Braun and Rogers (1971) found that the initiation of incubation was dependent on spring conditions (snow free areas) and varied from 5 June to 20 June exemplifying the potential plasticity in breeding timing for white-tailed ptarmigan. Giesen et al. (1980) found the median hatch date over a 12-year period at Rocky Mountain National Park was 15 July (6 July-23 July). Our surveys found a similar peak hatch date of 18 July which is in contrast to recent research that found hatch dates to have progressed as much as 15 days earlier (Wang et al. 2002, Wann et al. 2016). Though June temperatures have warmed substantially based on SNOTEL data (Figure 1), abundant snow fall during our study resulted in white-tailed ptarmigan delaying nesting until snow-free ground was available. High snow years have been found to delay reproduction and result in lower renesting rates, likely impacting productivity (Clarke and Johnson 1992, Martin and Wiebe 2004). Thus, if current predictions of an increase in winter precipitation due to climate change are accurate (Lukas et al. 2014), timing of nesting may not be altered even with increases in spring temperatures. Adaptively, white-tailed ptarmigan can alter breeding to respond to variation in snow depth at breeding sites. If early hatching does occur due to warmer spring temperatures, this could lengthen the reproductive period allowing for additional renest opportunities for females with failed nests. As we observed at the Ophir site which had the highest snow levels and delayed melt, no renesting attempts were documented and productivity was lower there than at the other sites surveyed. Giesen and Braun (1979b) estimated that renesting occurred in eight of 12 years on their study area in Rocky Mountain National Park, and accounted for 11.5% of annual productivity. We found that timing of nesting was similar to what has been reported in the past and our estimate of 14% renesting attempts is similar to other research with adult females renesting at a higher rate than 120 Page �CPW 2018 White-tailed Ptarmigan subadults. This mirrors what other investigators have found with older females having an increased prevalence to renest (Wiebe and Martin 1998a, Sandercock et al. 2005a). The average clutch size documented at our four sites across Colorado was similar to extensive studies in Colorado from 1966-1977 at study sites along the Front Range, Independence Pass in the Collegiate Mountains, at Mesa Seco in the San Juan Mountains (Giesen et al. 1980), and at Mt. Evans where nest surveys were completed in the late 1980s to 1993 (Martin et al. 2015). These surveys found an overall average clutch size of 5.9 (range 2-9) for all age classes. Lower average clutch size (4.9, range 5-7) has been documented at sites in the Mineral Belt in the San Juan Mountains (Larison 2001). Studies in Colorado have documented clutch sizes as large as eight to nine eggs, whereas we never documented more than seven eggs in a nest. This may account for the larger average clutch size from earlier studies. These earlier studies occurred over longer time periods and followed more nests (358 nests), which may account for the rare detection of a few clutches as large as eight or nine eggs. For other subspecies of white-tailed ptarmigan, less detailed information is available on clutch size, but in Montana average clutch size was found to be 4.8 (range 3-6) for nine nests (Choate 1963), on the British Columbia mainland 5.8 (range 3-8) for 12 nests (Campbell et al. 1990), and for Vancouver Island an average of 6.0 eggs (range 5–7, n = 9 nests; Martin and Forbes 2001, Martin et al. 2015). White-tailed ptarmigan in the Yukon Territory, Canada have the largest average clutch size reported with 7.1 (Wilson and Martin 2011). Embryo viability for whitetailed ptarmigan has been found to range from 88–97% (Wilson and Martin 2011, Giesen et al. 1980); therefore the viability measured to be 95% in our research was similar to other findings. Nest Survival Braun and Rogers (1971) reported nesting success over a 4-year period (1966-1969) at five different areas (Rocky Mountain National Park, Mesa Seco, Mt. Evans, Crown Point, and Independence Pass) to vary from 25-75%. In Sierra Nevada, California surveys conducted from 1982-1987 found nest success to have high variation (25-61%; Clarke and Johnson 1992). More 121 Page �CPW 2018 White-tailed Ptarmigan recent estimates in Colorado over a 3-year period (2013-2016) at three study sites (Mt. Evans, Rocky Mountain National Park, and Mesa Seco) had 56% of the nests surveyed successfully hatch. Thus the percent of nests that successfully hatched (57%) during our surveys are well within the expected range for the species. In addition, our nest survival until hatch of 0.393 was found to be higher than the estimate of 0.24 measured in Colorado at Mt. Evans from 1987-1996 (Wilson and Martin 2011), and for measures by Sandercock (2005a and b) who found the probability for nest success varied from a low of 0.292 to a high of 0.333 at four study sites in the vicinity of Mt. Evans over 10 years. Nest failures at our sites were attributed predominantly to mammalian predation based on the removal of eggs from the nest. Many other studies have also attributed the preponderance of whitetailed ptarmigan nest failure to mammals (Giesen 1980, Braun and Rogers 1971, Wiebe and Martin 1997). However, cameras used to monitor nest predators of Greater sage-grouse (Centrocercus urophasianus) found that identifying either mammalian or avian nest predators based on egg removal, the presence of egg shells, or other sign was not possible (Coates et al. 2008). Wiebe and Martin (1997) found that based on data loggers placed in nests to evaluate recess periods and abandonment; that most predation of white-tailed ptarmigan nests occurred at night indicating a high rate of mammalian predation as owls are rare predators in the alpine. Future studies could incorporate the use of cameras at nest sites to determine the predator species having the greatest impact on nest survival to inform future management purposes and to better understand annual variation in predation. The yellow-bellied marmot has not been discussed by other researchers as being a nest predator and we found no evidence for them raiding nests however; ground squirrels and rodents have been cited as nest predators of Greater sage-grouse (Braun et al. 1977, Ritchie et al. 1994, Johnson and Braun 1999). Thus further work could investigate the potential of marmots as nest predators as this species can be very abundant in the alpine and their population density and 122 Page �CPW 2018 White-tailed Ptarmigan behavior may change in relation to climate change. Inouye et al. (2000) has documented that with warmer springs marmots are emerging earlier from hibernation. The level of predation risk we encountered was similar to other studies that have found greater than 60% loss of nests to predators (Giesen 1980, Wiebe and Martin 1998b, Sandercock 2005a, and b, Wilson and Martin 2011). We found that females generally survived the depredation event with only a few sustaining an injury (e.g., we found a female limping with a toe missing after locating a predated nest). This is similar to other studies that found 9% of females died on nests due to predation (Wiebe and Martin 1997, 1998b). Weather can also impact nest success. High snow years have been found to reduce nest success whereas phenologically early years improved nest success (Braun and Rogers 1971, Clarke and Johnson 1992, Martin and Wiebe 2004 and 2006, Wilson and Martin 2010). For rock ptarmigan reproductive success was found to be positively associated with early appearance of snow‐free ground, and date of snowmelt accounted for most annual variation in reproductive success (Novoa et al. 2008). Choate (1963) found that extreme storms can cause nests to fail. We could not account for any of our nest failures to storms and the earliest and driest spring had low nest success due to high predation rates. Wiebe and Martin (1998b) examined 331 nests over nine years and found that after nests placed near boulders, willow (33%) was the second most common substrate followed by sedge (17%), and conifer (5%). Thus our nesting locations are similar to what other researchers have documented. Nests placed next to boulders and rocks have been found to be the preferred substrate as rocks are thought to provide better protection from wind and precipitation than the sparse vegetative cover in the alpine (Giesen et al. 1980, Wiebe and Martin 1998b). In addition, nests placed near boulders have been found to heat up quicker in the morning and remain cooler during the hottest part of the day resulting in these nests providing the best thermal environment for incubation (Wiebe and Martin 1997, 1998b). 123 Page �CPW 2018 White-tailed Ptarmigan Chick Survival Brood size can vary year-to-year and chick survival is thought to be impacted predominantly by predation (Martin et al. 2000). Martin et al. (1993) found that on average 32% of hens will lose their entire broods prior to fledging. The low survival of chicks in the South population in 2013 was most likely driven by high predation rates by long-tailed weasels at the Mesa Seco site. The density of weasels on the study site appeared high based on the number of observations of the animals recorded during each visit. In 2012, the American pika (Ochotona princeps) population appeared to be extremely abundant at Mesa Seco, but in 2013 it had declined. The increase in the numbers of long-tailed weasels in 2013 may have been a result of an increase in prey availability (pika) and with the decline in numbers of this prey species, weasels may have opportunistically selected for white-tailed ptarmigan eggs and chicks. After 2013, the sighting of weasels declined sharply and pika populations appeared to level off. These observations point to a community level dynamic that can vary depending on site conditions, predator numbers and composition, and alternate prey availability. Post-hatch weather may be an important abiotic factor related to reproductive success (Wann 2012). Ptarmigan chicks are precocial and leave the nests hours after hatching to feed themselves; yet the chicks are unable to thermoregulate and must return to the hen to brood. The brooding times are longer and feeding times shorter with drops in ambient temperature. Willow ptarmigan chicks have been found to tolerate extreme drops in temperature and hostile weather events as long as the duration is limited (Jörgensen and Blix 1985). Rock ptarmigan chicks in the eastern French Pyrenees and Japanese rock ptarmigan (L.m. japonica) have been found to be negatively impacted by rainfall especially during the first several weeks of life with their inability to regulate their body temperatures (Novoa et al. 2008, Kobayashi and Nakamura 2013). Most spring storms in the alpine in Colorado are limited to an afternoon occurrence with white-tailed ptarmigan being well adapted to these weather conditions. However, if storm duration changes and becomes 124 Page �CPW 2018 White-tailed Ptarmigan extended or more extreme due to climate change, young chicks may be at risk due to the need for increased brooding and a reduction in insect availability as a result of cold, wet weather. We did find dead chicks periodically on the alpine tundra during surveys that may have been unable to feed sufficiently due to colder weather or storms resulting in extended brood times and reduced foraging. However, we also had females move broods long distances within several days of hatch (one hen moved her chicks across Hwy 82 immediately after hatching and over several days, moved them >1 km from their original nest site) at which time chicks could become separated from their hen and unable to fend for themselves. Average annual productivity has been found to be 3.92 chicks hatched/female in Yukon, and 1.77 chicks hatched/female in Colorado (Wilson and Martin 2011). The annual fecundity was measured to be 1.04 from 1987-1994 at Mt. Evans (Wiebe and Martin 1998a) and Sandercock et al. (2005b) defining annual fecundity as the number of female fledglings per hen, found that over 10years (1987-1997) at four sites in Colorado that it was 0.4 + 0.08. Braun and Rogers (1971) stated that white-tailed ptarmigan must experience productivity of 40% or higher to maintain populations. Therefore, collective research in addition to our current assessment corroborate the finding that white-tailed ptarmigan have low reproductive output coupled with high demographic stochasiticity highlighting the importance of needed connectivity among alpine sites for immigration and the preservation of high female survival (Martin et al. 2000, Sandercock et al. 2005b, Hoffman 2006, Martin 2014, Wann 2017). Though the fecundity rates we measured may be below what is thought to maintain population viability for some years and sites; the extensive alpine habitat in Colorado allows for connectivity among populations. Thus in poor reproductive years at a site, due to high predation or unfavorable weather conditions, recruitment from outside sources for demographic rescue most likely occurs as is demonstrated with the high genetic diversity measured in Colorado (Langin et al. 2018). 125 Page �CPW 2018 White-tailed Ptarmigan Chapter 5 Resource Selection Introduction Understanding resource selection by a species across their range provides an opportunity to assess population health, develop conservation strategies, and evaluate potential impacts of stressors (Morris et al. 2016). The use of wildlife telemetry and the availability of various options of spatial data and advanced mapping software have led to expanded opportunities to assess species distribution and model resource use. Species distribution models can aid managers in predicting changes in distribution of an organism on the landscape caused by environmental changes (Jackson et al. 2015). Using radio telemetry data, we attempted to identify predictor variables that could be modeled to assess spatial distribution and resource use patterns of white-tailed ptarmigan in Colorado. If variables could be identified, we could incorporate them into climate change emission scenarios to identify critical areas and develop potential management strategies to mitigate environmental change impacts. Methods To evaluate habitat use of white-tailed ptarmigan throughout Colorado, we first used landscape layers relating to elevation, temperature, precipitation, topographic ruggedness (or, terrain roughness), land-cover/land-use type (mixed tundra, meadow tundra, prostrate shrub tundra, bare ground tundra, exposed rock, shrub dominated wetland/riparian, graminoid/forb dominated wetland, and mesic/upland shrub; all taken from CO-GAP), and with observed location data from radio-collared white-tailed ptarmigan. The origins of these layers overlap with the time stamp observed data were collected (i.e., within five years). Additionally, the resolution of these layers 126 Page �CPW 2018 White-tailed Ptarmigan captures the scale of habitat use demonstrated by white-tailed ptarmigan across two seasons: summer (mid-May to November) and winter (November to mid-May). There are no CO-GAP forecasts that allowed us to account for climate and land use/land cover change, a critical element of the analysis. Therefore, we used land use/land cover data from the USGS (agriculture, barren ground, deciduous forest, disturbed private land, disturbed publicprotected land, evergreen forest, grassland, hay-pasture, herbaceous wetland, ice-snow, mining, mixed forest, shrubland, and woody wetland; Zhu 2011, Zhu and Reed 2012). Additionally, we used climate change forecasts from the PRISM Climate Group (2004) relating to two emissions scenarios in three time periods and two seasons in both populations of white-tailed ptarmigan (Table 10). The landscape layers were used as covariate predictors in a generalized linear mixed logistic regression model (GLMM), with the used and available habitat serving as the response variable. That is, “Use” habitat was defined as the telemetry locations recorded for individual ptarmigan from 2013-2017. Available-habitat was defined as all locations within the defined PRM for the white-tailed ptarmigan. We selected one covariate layer each relating to a land use/land cover category (distance to barren ground), a topography category (elevation), and a weather category (seasonal mean precipitation) to use in a simulation to identify the minimum number of randomly selected available locations for which the coefficient values for the covariate layers would remain stable. In all season/population contexts the coefficient values remained stable when the ratio of available- 127 Page �CPW 2018 White-tailed Ptarmigan to-use-locations was less than or equal to 5:1. We therefore randomly selected five times as many available-locations as use-locations to ensure stability. To define which variables to include in the model for each emission scenario/year/season/population context we performed correlation analyses to identify redundant covariates. We then applied univariate regressions to identify which of a pair of correlated covariates served as a better predictor of use-habitat, and multivariate regressions to identify the top model in each emission scenario/year/season/population context. This process served to reduce our candidate covariate list in each case to improve computational efficiency. Results We used 3379 locations of white-tailed ptarmigan in our analysis. There were 2950 locations in the summer and 429 locations in the winter. Elevation associated with the observed locations ranged from 2914 to 4140 m, and 50% of all locations occurred between 3723 and 3850 m (Table 11). Values for these quantiles for all other considered covariate predictors are included in Table 12. For the contemporary (CO-GAP) data, in both populations and across both season, the posterior credible interval estimates for all covariates included 0, and thus we cannot say any particular covariate served as a significant predictor of white-tailed ptarmigan occurrence (Table 12). Similarly, for the forecasted (USGS EROS) data, in both populations and across both season, the posterior credible interval estimates for all covariates included 0 (Table 13). 128 Page �CPW 2018 White-tailed Ptarmigan Table 10. Climate change emissions scenarios, the time period for which they were forecast, and the seasons and populations considered in this analysis. Emissions Scenario Time period Season Population Representative Concentration Pathway (RCP) 4.5 (low) – radiative forcing at 4.5 watts per square-meter. Representative Concentration Pathway (RCP) 8.5 (high) – radiative forcing at 4.5 watts per square-meter. 2020s, 2050s, 2080s Summer, Winter North, South 129 Page �CPW 2018 White-tailed Ptarmigan Table 11. Elevation associated with locations of radio-collared white-tailed ptarmigan in Colorado during the defined summer season (mid-May to November) and in winter (November to mid-May). We recorded 3379 locations of white-tailed ptarmigan from 2013-2017; 2950 locations in the summer and 429 locations in the winter. Elevation (ft) 9500 - 10000 10000 - 10500 10500 - 11000 11000 - 11500 11500 - 12000 12000 - 12500 12500 - 13000 13000 - 13500 13500 - 14000 Elevation (m) 2895 - 3048 3048 - 3200 3200 - 3353 3353 - 3505 3505 - 3658 3658 - 3810 3810 - 3962 3962 - 4115 4115 - 4267 Summer Winter 0.0% 0.0% 0.1% 0.2% 5.0% 45.0% 45.0% 5.0% 0.1% 0.3% 1.0% 2.0% 6.0% 36.0% 45.0% 8.0% 0.9% 0.0% 130 Page �CPW 2018 White-tailed Ptarmigan Table 12. Quantiles (0.025th, 0.25th, 0.5th, 0.75th, and 0.975th) associated with each covariate layer for the locations at which white-tailed ptarmigan were reported. Precipitation values are in centimeters, temperature values are in degrees Celsius, and Topographic Ruggedness Index is a unitless index of terrain ruggedness. All other values are in meters (land cover class values are for distance to nearest raster cell of that type) or percent cover (percent of raster cell composed of that land cover class). Covariate 2.50% 25% 50% 75% 97.50% 0.00 3523.07 11010.39 14553.36 28869.10 3533.86 3594.01 3647.39 3679.74 3870.49 19035.24 21908.54 81110.95 86927.79 110845.74 33219.45 40135.76 66800.05 110588.16 129827.20 2774.77 8324.74 8325.91 22513.62 31345.03 14157.00 16422.42 45326.71 61672.24 94137.85 Mixed Tundra Distance 4414.52 7046.60 16329.30 19428.06 32444.00 Mixed Tundra % Cover 0.00 3.00 32.00 92.00 100.00 2774.94 5549.86 7046.60 18778.84 29143.38 Bare Ground Tundra Distance Elevation Exposed Rock Distance Graminoid-forb dominated Wetlandriparian Distance Meadow Tundra Distance Mesic Upland Shrub Distance Prostrate Shrub Tundra Distance Prostrate Shrub Tundra % Cover 0.00 0.00 0.00 0.00 71.00 Shrub Wetland-riparian Distance 34522.28 38030.45 101801.88 113548.23 115589.22 Summer Mean Precipitation 51.31 55.01 62.85 67.16 91.83 Summer Mean Temperature 4.53 4.76 6.00 6.52 7.09 300.55 378.70 420.57 460.43 522.93 Topographic Ruggedness Index 131 Page �CPW 2018 White-tailed Ptarmigan Table 13. Species-level model results and covariate 95% credible intervals (with mean posterior covariate estimate, and 2.5% and 97.5% credible intervals, CI) for models using Colorado Gap Analysis Project data. Population Season Deviance Predicted Error Covariate Mean 2.5% CI 97.5% CI North Summer 4092.173 0.138 bare_ground_tundra_dist 0.992 -113.957 126.511 North Summer 4092.173 0.138 exposed_rock_dist 2.425 -119.421 126.057 North Summer 4092.173 0.138 mesic_upland_shrub_dist -0.401 -120.589 125.227 North Summer 4092.173 0.138 mixed_tundra_pctcvr 2.758 -119.407 126.717 North Summer 4092.173 0.138 prostrate_shrub_tundra_dist -1.311 -128.535 121.060 North Summer 4092.173 0.138 summer_precipitation -0.526 -123.240 125.992 North Summer 4092.173 0.138 int -5.760 -136.706 117.826 North Summer 4092.173 0.138 gramforb_wetrip_dist 3.557 -126.505 134.908 North Summer 4092.173 0.138 mixed_tundra_dist 3.595 -119.835 130.539 North Summer 4092.173 0.138 shrub_wetrip_dist 0.151 -118.779 118.060 North Winter 912.495 0.218 bare_ground_tundra_dist -2.562 -126.293 120.685 North Winter 912.495 0.218 elevation -1.757 -122.870 112.337 North Winter 912.495 0.218 prostrate_shrub_tundra_pctcvr 0.741 -124.756 133.041 North Winter 912.495 0.218 int -2.496 -126.224 118.623 North Winter 912.495 0.218 gramforb_wetrip_dist 1.880 -127.297 131.256 North Winter 912.495 0.218 shrub_wetrip_dist -1.693 -128.660 120.422 South Summer 3593.469 0.113 bare_ground_tundra_dist -0.909 -129.667 125.434 South Summer 3593.469 0.113 elevation 3.751 -119.711 136.703 South Summer 3593.469 0.113 exposed_rock_dist 0.972 -122.033 123.348 South Summer 3593.469 0.113 mesic_upland_shrub_dist 2.040 -117.951 127.116 South Summer 3593.469 0.113 mixed_tundra_pctcvr -3.556 -121.251 111.555 South Summer 3593.469 0.113 prostrate_shrub_tundra_dist -2.285 -132.691 127.729 South Summer 3593.469 0.113 prostrate_shrub_tundra_pctcvr 0.557 -116.857 131.030 South Summer 3593.469 0.113 summer_precipitation -0.791 -131.027 127.600 South Summer 3593.469 0.113 int -4.875 -135.484 112.008 South Winter 895.665 0.217 bare_ground_tundra_dist -1.220 -122.192 118.547 South Winter 895.665 0.217 elevation 1.224 -127.916 138.715 South Winter 895.665 0.217 mixed_tundra_pctcvr 0.155 -119.826 131.044 South Winter 895.665 0.217 prostrate_shrub_tundra_dist -1.465 -134.309 131.032 South Winter 895.665 0.217 int -2.222 -137.389 124.393 South Winter 895.665 0.217 tri 0.271 -120.974 128.244 South Winter 895.665 0.217 winter_precipitation -0.113 -121.688 123.762 132 Page �CPW 2018 White-tailed Ptarmigan Discussion The resolution at which we attempted to assess white-tailed ptarmigan distribution and resource use was insufficient to identify predictor variables of occurrence. Therefore, we could not develop a model to forecast impacts to white-tailed ptarmigan resource use based on future climate change emission scenarios. The USGS EROS layer is at a 250 m spatial scale and the PRISM layers for climate projections are projected at 800 m whereas, white-tailed ptarmigan are interacting with the landscape at a much finer scale with rare "long" (peak-to-peak) dispersal events. In addition, the PRM sufficiently described likely white-tailed ptarmigan habitat; trying to further predict the relative probability of suitable habitat within that restricted range was unsuccessful given the resolution of the input data relative to that area within that range. We would require much finer resolution data to distinguish suitable microhabitat areas within the PRM. However, the results confirmed that our PRM was an excellent predictor of suitable habitat for the species at the landscape scale, emphasizing the importance of protecting the entirety of Colorado’s alpine to maintain viable populations of white-tailed ptarmigan. Within the PRM, white-tailed ptarmigan use a variety of habitats during different seasons. In the breeding period they rely on mesic vegetation for brood rearing and cover for nests. In the fall they congregate on steeper, drier slopes further from the lower elevation breeding areas. In winter, willow for forage is important as well as snow quality and quantity for roosting. Determining habitat needs and modeling spatial distribution on a scale of “use” can be difficult for a 350 g avian species that relies on microrefugia where microclimate, plant species composition, and terrain structure differ. Future surveys designed to adequately assess resource use will need to use a finer digital representation than what is currently available, or design field collection studies to examine microsites to help define variables that differentiate use versus available habitat. This assessment may become more complicated as climate change progresses and white-tailed ptarmigan use of habitats is altered as they adapt to new environmental conditions. Every year depending on 133 Page �CPW 2018 White-tailed Ptarmigan weather, we found white-tailed ptarmigan using novel areas. For instance, during one abnormally warm fall with delayed snowfall, we found white-tailed ptarmigan moving down in elevation to find relief from the heat under willow carrs. We also observed brood areas change depending on moisture, snow melt, and predator activity. However, there were also common use areas where surveyors could normally find white-tailed ptarmigan occupation every year. Deciphering the fine scale choices the bird makes is not an easy task, but without this information, alterations in the alpine due to climate change and resultant impact on the bird cannot be determined. One concern as to the potential negative impact of climate change on white-tailed ptarmigan is predicted tree encroachment into the alpine. This encroachment would undoubtedly reduce habitat suitability for the species, increase fragmentation, and potentially limit connectivity. Localized modeling by the USFS in Colorado (Rondeau et al. 2016) has predicted trees will move upslope into the alpine. This encroachment will cause habitats to become unsuitable for breeding and fall residency and may also allow competitive species such as dusky grouse and predators to become more prolific in the white-tailed ptarmigan range. However, with the high incidence of Spruce (Ips typographus) and mountain pine beetle (Dendroctonus ponderosae) kill and increases in annual wildfires in Colorado, tree encroachment into the alpine may not happen at the rate or extent that has been modeled. The layers available at the scales required for this study are insufficient to model the increase in stochastic events and extreme weather. If stochastic events impact reproductive output on a frequent basis, recovery from these events is limited and long-term population projections may decline. Another problematic area of climate change predictions is determining how the summer thunderstorm regime will be altered. These afternoon storms are very common in July and August and are responsible for reduced afternoon temperatures. If storms decline in frequency and temperatures in July and August increase, the white-tailed ptarmigan may be negatively impacted due to changes in forage, reduction in mesic sites, and loss of persistent snow fields. Benson and 134 Page �CPW 2018 White-tailed Ptarmigan Cummins (2011) found that white-tailed ptarmigan at Glacier National Park have changed their distribution by moving upslope a distance of 335 m, altered their use of habitats, and experienced a local population decline as a consequence of increases in temperature and a reduction in persistent snowfields. Without the continued monsoonal patterns in the alpine, we may see similar patterns in Colorado. 135 Page �CPW 2018 White-tailed Ptarmigan Management Implications The CPW status assessment for the white-tailed ptarmigan included statewide surveys that investigated demographic parameters, reproductive success, and resource selection to evaluate the subspecies potential to maintain viable populations into the future. Overall population trends for the state, North and South populations appeared stable with predicted extinction probabilities extremely low. Mining and sheep grazing continue today in the alpine, though at reduced levels as compared to the past. These impacts have been occurring in the state since the late 1880s, thus it appears that white-tailed ptarmigan have survived and adapted to these disturbances, though we have no preabundance or demographic information prior to these activities being established on the landscape. These two disturbances may have low level fitness costs as detected by Larison (2001) and from our observations of domestic sheep disrupting and separating broods from hens. Domestic sheep grazing can alter the alpine vegetation community and these impacts may become exacerbated with climate change. The USFS and BLM should ensure that sheep grazing is included in an adaptive management approach to protect alpine habitats from further degradation as a consequence of warmer springs, earlier snow melt, and potentially overall higher spring and summer temperatures. Hunting of white-tailed ptarmigan in Colorado predominantly occurs in areas that are easily accessible by vehicles and ATVs and are in close proximity to large human population centers. One such area is Mt. Evans where Wann (2017) documented negative implications of harvest with extinction probabilities amplified and population growth rates reduced. Hunting in these localized areas should be monitored and managed by CPW to avoid negative impacts. Currently little information is available to assess hunting pressure, though statewide impacts to the white-tailed ptarmigan population are likely negligible. 136 Page �CPW 2018 White-tailed Ptarmigan Recreation in the alpine has increased dramatically over the seven years that this study was undertaken (A. Seglund, personal observation). Recreation can impact white-tailed ptarmigan by pushing them out of preferred areas, altering their behavior, adding additional stress during critical times of the year such as breeding and winter roosting, and attracting generalist predators. To help reduce this impact, requirements should be posted at popular trailheads for pet owners to keep dogs close and under voice command, for skiers and snowmobilers to avoid important willow foraging areas, to continue to educate the pack-it-in-pack-it-out mentality to reduce garbage that may attract predators, and limit and manage the type of recreation occurring so that it is compatible to the resource being used. Alpine habitats are fragile and therefore, federal agencies should consider limiting certain types of recreation activities in the alpine tundra and monitoring site visitation to make sure areas are not being overused and damaged. White-tailed ptarmigan are not well adapted to high ambient temperatures with white-tailed ptarmigan having the lowest evaporative efficiency measured in birds (Johnson 1968). To deal with summer heat, birds behaviorally adapt by selecting cool microsites, bathing in snowfields, and fluttering their gular skin. White-tailed ptarmigan summer habitat is extensive in Colorado with abundant microsites (small change in aspect or elevation can alter amount of moisture accumulation, temperature, wind velocity, and vegetation) for the birds to exploit to avoid overheating. Though temperatures are increasing in the alpine, Colorado has maintained a buffer from extreme temperatures in summer due to typical afternoon thunderstorm moisture. Rarely do temperatures rise above 68°F from June-August (Snow Telemetry (SNOTEL) - Natural Resource Conservation Service (NRCS) National Water and Climate Center data) and when they do, it is for a limited duration until the afternoon thunderstorms commence and the high elevation habitats cool. Because alpine temperatures in Colorado rarely reach high levels, birds appear less dependent on persistent snow as compared to sites in Montana where they have been found to follow the retreating snowfields (Benson and Cummins 2011). Birds have rarely been detected panting on our 137 Page �CPW 2018 White-tailed Ptarmigan study sites, though they have been observed bathing in snowfields and taking cover in the shade of willows during a warm fall when snow was not available. If the current afternoon thunderstorm trend is altered and summer daily temperatures warm with no respite, persistent snow could become a needed resource for white-tailed ptarmigan in Colorado as they search for cooler areas. Afternoon thunderstorms, in addition to tempering summer temperature, are also very important for maintaining verdant vegetation that would desiccate and become less productive without the almost daily moisture. This could also reduce insect availability impacting young chicks that need this protein immediately after hatching. Persistent snowfields may grow to be important to maintain mesic areas if afternoon thunderstorm patterns are reduced. White-tailed ptarmigan winter habitat appears to be a more limited resource owing to access and extent of willow carrs across the landscape. Wann (2017) attributed population declines of white-tailed ptarmigan at Rocky Mountain National Park in part to degradation of these areas by over browsing by elk. Colorado is home to a large number of elk and also to moose (Alces alces) that depend on willow for forage. Over most of the areas we examined, willow is extensive and in good condition. However, if grazing by wild ungulates and sheep is not properly managed, issues could arise especially with the added stress of climate change. With changes in precipitation patterns and earlier snowmelt, willow carrs could be in jeopardy of inadequate moisture and drying out of stands occurring. Maintenance of hiking trails and ATV roads that become deeply incised are needed to properly disperse rain and snowmelt runoff to avoid the dewatering and drying out of meadows, wetlands, and willow carrs to preserve winter habitat for white-tailed ptarmigan. Though it appears that this alpine endemic species is resilient and populations and distribution across the state are stable, continued monitoring of the species is warranted. Occupancy surveys should be conducted every three years to assess changes in distribution. Feather samples from birds should be collected during these surveys to evaluate any changes in the genetic makeup of populations that may be an indication of inbreeding or genetic drift. Augmentation of isolated areas 138 Page �CPW 2018 White-tailed Ptarmigan such as the Flat Tops may be necessary to maintain local populations at a level to sustain viability through time. Evaluation of changes in vegetation should be part of the monitoring program to help assess impacts to the species that may be occurring due to a reduction in food quality. CPW is currently developing a long-term alpine monitoring program that will allow periodic evaluation of the white-tailed ptarmigan incorporating these methods. The alpine ecosystem is not a homogenous landscape, but one with abundant microclimates that the white-tailed ptarmigan can exploit to potentially buffer some environmental change. Colorado provides the species with abundant suitable habitat and hence even with localized anthropogenic disturbances; white-tailed ptarmigan currently have the ability to avoid high use areas. As managers continue to monitor and assess the species, they need to be aware of the synergistic threats of environmental and human impacts that could push white-tailed ptarmigan into limited spaces and increase stressors that could reduce population viability. Agencies must work together to limit disturbances in the alpine and mitigate those that currently exist. Environments are changing with many unknown consequences on the horizon, thus it is imperative for CPW to continue to monitor and work with agencies to manage this iconic alpine species for future generations to enjoy. 139 Page �CPW 2018 White-tailed Ptarmigan Conclusions 1. There is adequate gene flow to maintain high genetic diversity with currently no indications of severe effects of small population sizes or deleterious effects of inbreeding. 2. The statewide and the South population appear stable with high predicted persistence into the future. The North population had higher estimated extinction into future, but currently appears to be stable. When potential immigration parameters were included in the PVA, extinction projections resulted in a 0% estimated extinction probability for all populations even with the inclusion of weak immigration. 3. Reproductive output showed annual variability and was impacted predominantly by predation and to a lesser extent weather. 4. White-tailed ptarmigan are widely distributed across the state in all suitable habitats defined within the PRM. Identification of predictor variables of occurrence that could be used to model future environmental changes could not be identified. 5. Long-term management of the species may be warranted at localized sites and in the face of environmental change. a. The increase in recreation in the alpine will need to be managed to avoid deleterious impacts to localized population areas of white-tailed ptarmigan. b. Hunting pressure should be monitored at sites that are easy accessible to avoid localized negative impacts. c. Sheep grazing needs to be managed to avoid overuse of habitats especially in drought years and in light of changing environmental conditions. 6. 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For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Southern White-tailed Ptarmigan (Lagopus leucura altipetens) Population Assessment and Conservation Considerations in Colorado Description An account of the resource Status of the southern white-tailed ptarmigan (Lagopus leucura altipetens) in Colorado was assessed from 2013-2017 using a number of metrics to determine trends in abundance, survival, site fidelity, reproductive success, resource selection, and genetic structure. The species inhabits naturally fragmented alpine habitats that have been, and are currently impacted by anthropogenic threats that predominantly include climate change, sheep grazing, hunting, mining, and recreation. Fine-scale genetic structure was apparent between the San Juan Mountains (South population), and those in the central and northern mountain ranges (North population). Though some isolated pockets of white-tailed ptarmigan reside in the state (i.e., Flat Tops and Sangre de Cristo), there is adequate gene flow across Colorado to maintain high genetic diversity with currently no indications of severe effects of small population sizes. Creator An entity primarily responsible for making the resource Seglund, Amy Street, Phillip A. Aagaard, Kevin Runge, Jon Flenner, Michelle Subject The topic of the resource Southern white-tailed ptarmigan <em>Lagopus leucura altipetens</em> Colorado Population assessment Conservation Extent The size or duration of the resource. 152 pages Date Created Date of creation of the resource. 2018 Rights Information about rights held in and over the resource <a href="http://rightsstatements.org/vocab/NoC-NC/1.0/">No Copyright - Non-Commercial Use Only</a> Type The nature or genre of the resource Text Format The file format, physical medium, or dimensions of the resource application/pdf Language A language of the resource English Publisher An entity responsible for making the resource available Colorado Parks and Wildlife