https://cpw.cvlcollections.org/files/original/d34521ae5cabf71fdd6f00adbe536189.pdf faa1478492ed7f4342e90d4a808f378b PDF Text Text PINYON JAY BREEDING COLONY SUMMARY INVESTIGATION Southwest Colorado 2020 Photo by Aaron Yappert Prepared by: Amy Seglund, Liza Rossi, Jon Runge, Michelle Flenner, and Kevin Aagaard. Colorado Parks and Wildlife. January 2021. �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Summary of Findings: Pinyon jays (Gymnorhinus cyanocephalus) are thought to be declining range-wide (Boone et al. 2018). Very little is known about their breeding status and habitat use in Colorado. In 2020, Colorado Parks and Wildlife examined six breeding colonies in Montrose and Delta counties to assess colony size and structure, hatching and fledging success, potential threats to reproductive output, and colony site fidelity. Six additional colonies located in western Colorado in 2019 were surveyed a single time during the breeding season to determine site fidelity. At the six intensively studied colonies, 74 new nests and 188 old nests from previous years were located; the mean number of nests per colony (including both old and new nests) was 76. Colony size ranged from 34 to 224 ha. Distances between new nests within a colony ranged from a minimum distance of 12 m to a maximum distance of 2347 m. Incorporating a cluster analysis to evaluate colony structure, we found two colonies that had six unique clusters of nests, one had four, two had three, and one had two clusters with the mean number of nests per cluster being 33. Using the nest success module in Program MARK to analyze hatching and fledging success for pinyon jays, we found 57 nests had sufficient information to determine hatching success and 43 for fledging success. The chance of a pinyon jay nest surviving from beginning of incubation to hatch was 56% (95%CI: 40-70%), and surviving through to a 15 day fledging period (hatch to fledging) was 46% (95%CI: 31-60%). We found nests placed lower in trees and with a greater number of jays counted at a colony improved hatching success. For fledging success, nests in pinyon pine trees demonstrated higher fledging success than those located in juniper, but regardless of tree species, fledging success decreased with tree height. Nests located in larger clusters saw reduced fledging success. Predation appeared to be the number one cause of nest failure. Of the additional six colonies visited to assess site fidelity; four were found to be active with new nests and/or fledglings detected, one colony was found to have pinyon jays present but no new nests were located, and the final colony had no pinyon jays detected during the survey. 2 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Acknowledgements: This project would not have been possible without the incredible field crew that completed the survey work and helped develop the study design. The crew included Aaron Yappert, Amy Sullivan, Marissa Markus, and Lee Sutcliffe. This crew worked tirelessly to locate pinyon jays, to gain an understanding of breeding behaviors, and to find nests. We would also like to acknowledge Shawn Conner from BIO-Logic, Inc. who was instrumental in finding both the Shavano Valley and Beaton Creek colonies to include in our survey effort. Shawn also provided much needed expertize in understanding pinyon jay behavior and identification of nests. Finally, funding for this project was provided by the Bureau of Land Management. 3 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Introduction: Throughout Colorado, pinyon jays (Gymnorhinus cyanocephalus) are a relatively common resident of pinyon-juniper woodlands (Pinus edulis, Juniperus osteosperma, J. monosperma, J. scopulorum). These woodlands occur in arid regions at elevations between 1,370 and 2,290 m (4,500 to 7,500 feet) and account for about 21% of the forested landscape in Colorado (https://csfs.colostate.edu/coloradoforests/forest-types/pinon-juniper-woodlands/). Pinyon-juniper woodlands generally transition from grasslands or shrublands at lower elevations, to juniper becoming more abundant with pinyon pine dominating at higher elevations (Daubenmire 1943, Gottfried et al. 1995, Gori and Bate 2007). Though pinyon pine nuts are a rich food resource, the heavy cone crops produced by pinyon pines occur on average, only one to three years out of ten making this food resource unpredictable (Gori and Bate 2007). The aptly named pinyon jay has evolved a mutualistic relationship with the pinyon pine to deal with the unreliability of these mast crops (Ligon 1978, Johnson and Balda 2020). These specialized jays seek out and harvest the nutritionally packed pine nuts, collecting up to 50 nuts in their expandable esophagus, and transporting the wingless seeds miles before caching them for later retrieval (Ligon 1978). The ability of pinyon jays to nest early is primarily due to this caching behavior, in addition to their construction of thick insulated nests to protect young from freezing conditions. Though jays have an exemplary ability to relocate cached nuts, those few buried nuts not later retrieved for food result in seeds germinating. This caching behavior thus plays an important role in regenerating and expanding pinyon pine forests, as well as enabling pinyon jays to have the longest and earliest breeding seasons of any passerine (Johnson and Balda 2020). Pinyon jays breed collectively as a group in loose colony sites that are used over multiple years (Marzluff and Balda 1992). Breeding colony areas encompass a variety of vegetation types and topographies (Johnson et al. 2016). Sites often have patches of trees for nesting interspersed with sagebrush (Artemisia spp.) and grasslands to increase access to insect prey for young nestlings. Cache sites within colonies are characterized by bare ground that are south or southwest facing making these the first areas to be devoid of snow (Ligon 1978). Pinyon jays have been found to have high site fidelity even though colony boundaries and number of nests within colonies fluctuate from year to year (Marzluff and Balda 1992, Petersen et al. 2014, Johnson et al. 2017). Existing research on pinyon jay nesting is limited in scope with studies mainly occurring in Arizona and New Mexico (Marzluff 1988, Marzluff and Balda 1992, Peterson et al. 2014, Johnson et al. 2015, Johnson et al. 2019). These studies may or may not reflect how pinyon 4 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 jays are behaving or using landscapes in Colorado for breeding. For example, the Arizona studies were conducted predominantly in a ponderosa pine (Pinus ponderosa) forest using a town flock that appeared to rely heavily on local bird feeders. Current literature suggests that there have been dramatic declines in the numbers of pinyon jays across the species range since 1967, with these declines thought to be more pronounced than for any other broadly distributed landbird in the interior west (Boone et al. 2018). The reasons for these measured declines are unclear but could be associated with habitat alterations across the range, degradation of pinyon-juniper woodlands, climate change, extensive pine beetle kill, fire suppression, and increases in nest predator populations such as common ravens (Corvus corax), and American crows (C. brachyrhynchos). Despite these reports of range-wide declines, extremely limited information exists in Colorado regarding pinyon jay ecology and population dynamics. Pinyon jays are listed as a Tier 2 Species of Greatest Conservation Need in the Colorado State Wildlife Action Plan (CPW 2015), a Species of Conservation Concern by the U.S. Fish and Wildlife Service, and are included on the Partners in Flight “D” Yellow Watch List which identified species experiencing steep population declines and who will require full life-cycle conservation to reverse declines (Wiggins 2005, Rosenberg et al. 2016). In 2019, Colorado Parks and Wildlife (CPW) initiated a cooperative project with Utah Division of Wildlife Resources and the U.S. Fish and Wildlife Service to locate pinyon jay colonies in the Great Basin and Colorado Plateau. These initial baseline surveys were designed to develop a protocol to find colonies and determine colony distribution. Since these surveys began, 18 active colonies (defined as detecting a female incubating, eggs or nestlings in a nest) have been found in the state of Colorado. Colonies have been located in a variety of topographies and elevations, but all colony sites have been situated in pinyonjuniper woodlands. No colonies have yet been located in ponderosa or other pine habitats. Breeding in Colorado during these surveys has been found to begin mid-February, depending on elevation. In addition to identifying active breeding pinyon jay colony locations, CPW also deemed it necessary to evaluate colony spatial extent and structure, gauge variability in colony flock size and associated nest density, identify threats to reproductive success, and determine colony site fidelity. To get at these informational needs, we began a 2020 intensive colony survey effort at six known colony locations. The goals and objectives for this effort are listed below. The project will continue in 2021 and this report is a summary preview of the 2020 results and plans for the 2021 field effort. 5 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Goals:    Develop methodology to monitor pinyon jay colonies through time to assess trends in breeding population status. Identify potential threats that may negatively impact colonies to guide improved management for the species. Develop Best Management Practices for proposed vegetation treatments in pinyon-juniper habitats where pinyon jays occur. Objectives:      Assess nesting phenology and individual variation in timing of incubation and fledging to inform survey/monitoring protocols and habitat treatment implementation. Map extent and structure of known colonies. Determine active nest density within identified colony boundaries and assess how it relates to flock size. Determine feasibility of evaluating nest and fledging success, and identify potential impacts to reproductive output. Evaluate annual site fidelity and movement of colonies. Methods: Study Areas Eight pinyon jay colonies were identified in Colorado during the 2019 grid surveys (CPW and BIO-Logic, Inc. ongoing effort). Two of these colonies were used to investigate the above outlined objectives. Four additional colonies near the city of Montrose detected by local biologists were also investigated for this survey effort for a total of six colonies intensively evaluated (Figure 1). The remaining six colonies located in 2019 not used for the intensive monitoring effort, were revisited once during the breeding season to inform breeding colony site fidelity (Figure 2). Survey efforts followed closely the protocol for monitoring pinyon jays in New Mexico developed by Peterson et al. (2015). 6 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 The colonies intensively evaluated in Delta and Montrose counties (Figure 1; photos Appendix A) were:       Beaton Creek Dave Wood Duckett Draw Smith Mountain Shavano Valley Transfer Road Intensive Colony Surveys Surveys at colonies were initiated in mid-February with a minimum of two observers collecting data. Surveys were initiated at locations where new nests had been documented in 2019. However, the area that observers could search and follow pinyon jays was not limited to a defined search area. Observers were able to follow and observe jays wherever they traveled in order to identify colony spatial extent and movement. Observers arrived 30 minutes before sunrise to setup an observation point above the colony (e.g., ridgeline or other highpoint) or at an observation point in or near the colony where birds could be observed. During the early breeding season when courtship behavior was being documented, observers were very quiet and limited movement when working in and around the colony to avoid disrupting or modifying behavior of the birds. The objectives of the early season surveys were to document breeding behaviors, obtain an estimate of bird numbers and breeding pairs within the colony area, assess potential nesting colony extent or movement of a colony area from previous years, and evaluate phenology of annual nesting. Observed breeding behaviors were noted as well as the time they occurred, a description of what was observed, and the number of birds involved. To ensure all observers were aware of the progression and location of breeding at each colony, locations of where breeding behaviors occurred were projected onto the Avenza Maps application and uploaded each day to share among all field staff. Observations at a breeding colony lasted until 11:00 am or until activity at the colony subsided. 7 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Breeding behaviors (Johnson and Balda 2020) recorded were:          Silent Food Transfer (FT) Courtship Begging (CB) Silent sitting (SS) Swagger Walk (SW) Stick Manipulation (SM) Rattle calls (R) Pairs flying together or in a small family group (PF) Mobbing of intruder by birds (M) Carrying nest material such as sticks or lining material (CNM) Once breeding behavior activity declined in frequency and birds were predominantly incubating, surveyors quietly walked through colonies to locate nests. All nests located, both new as well as old nests from previous years, were marked using a Garmin GPS unit. At each nest found, observers collected a UTM coordinate at the nest tree, recorded the tree species the nest was located in, the nest and tree height, distance of the nest from the trunk of the tree, and distance from the observer to the tree when the nest was first spotted. Each new nest located was subsequently visited every four days to evaluate hatching and fledging success. 8 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Figure 1. Location of six pinyon jay breeding colonies intensively evaluated in 2020 in Montrose and Delta counties in western Colorado. 9 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Female pinyon jays incubate eggs almost continually for 17 days and brood nestlings, depending on brood size, for 8-10 days (Johnson and Balda 2020). Birds normally fledge at 21-22 days, but can survive if they leave the nest as early as 15 days (Marzluff and Balda 1992). If a female was incubating, observers could normally see her head above the nest from an observation point away from the nest (Appendix B). If the female was on the nest it was noted and observers immediately left the area. Nests were only approached and examined when a female was away from the nest and no pinyon jays were in the immediate vicinity. If when visiting a nest, potential predators were in the area, observers waited for the predators to leave before continuing their survey effort. Mirrors attached to telescoping poles were used to inspect contents of a nest to count eggs or nestlings, and to estimate the age of nestlings (Marzluff and Balda 1992, Johnson and Balda 2020). All potential predators detected while surveying a colony were recorded. Nest fate was quantified as follows: 1) Nest construction was initiated but never completed, 2) Female initiated incubation but eggs did not hatch, 3) Female initiated incubation and the eggs hatched but nestlings did not fledge, 4) Female initiated incubation, eggs hatched, and nestlings fledged (survived to > 15 days), or 5) unknown due to inability to see into a nest or not enough nest checks to ascertain fate. Causes of nest failure were thought to be due to predation if a female was documented to be incubating, but upon a follow-up nest check, the female was off the nest and all eggs were absent or eggs were broken, nestlings were missing, or a nestling carcass was found near a nest. If a nest had appeared to fail, the nest structure/condition was noted and the immediate area was searched for any evidence of potential predation (e.g., shell fragments, a hole in the nest, the nest has been torn apart, dead nestlings nearby, etc.). Predator identity was inferred based on findings by Marzluff (1988): 1) common raven or American crow if all eggs and nestlings were removed and nest was intact, 2) jay spp. if the eggs were still in the nest but had holes pecked in them or were broken, 3) rock squirrel (Otospermophilus variegatus) if eggs and young were removed and nest lining was disturbed, and 4) great horned owl (Bubo virginianus) if nest and eggs were crushed or young were found dismembered around the nest (Appendix C). If a nest was found with a complete clutch of eggs and the female was not seen incubating for a minimum of two nest visits, the nest was considered abandoned. 10 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Statistical Analysis Cluster analysis All nests located during surveys were transformed and projected to longitude and latitude coordinates (datum = WGS84). Some data had to be corrected to account for the boundary of UTM Zones 12 and 13 bisecting the study area. We conducted all analyses in R (R Core Team 2020) version 4.0.2. We conducted cluster analysis using the Mclust function from the package “mclust” (Scrucca et al. 2016) to identify the optimal number of clusters per colony (maximum of 20 clusters). This function uses Gaussian finite mixture models fitted via an Expectation-Maximization algorithm to identify the optimum number of clusters in a set of data. We forwarded the optimum cluster number into the function NbClust from the package “NbClust” (Charrad et al. 2014). This function offers a suite of distance metrics, cluster analysis method, and index to use to calculate the most parsimonious clustering scheme for a dataset, given a range of possible clusters. We used the Euclidean distance metric given the small spatial extent of the study area and colonies. We also used the centroid method and the kl (short for Krzanowski and Lai) index. We categorized any nest that was found to group with fewer than five other nests as not belonging to a cluster (i.e., a cluster had to consist of at least 5 nests). We calculated the minimum convex polygon (100% isocline) surrounding a cluster of nests using the function mcp from the “adehabitatHR” package (Calenge 2006). Nest Success We used the nest success module in Program MARK to analyze hatching and fledging success for pinyon jays at colonies. We attempted to fit models for nest building success as well but had insufficient data to do so. We used Akaike’s Information Criterion (AICc) to fit and rank models. We derived model weights (wi) for each model according to the procedure outlined in Burnham and Anderson (2001). Hatching success For the hatching success analysis we investigated whether the following variables influenced success: tree species (juniper or pinyon pine; treesp ), a measure of nest placement (one of: tree height; TreeHt, nest height; NestHt or distance of nest from trunk; trunkdist), a measure of pinyon jay abundance in a colony (one of: pinyon jay count within colonies during surveys; PIJAcnt, nest cluster size; clustsize; mean distance 11 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 among nests, nestdist), distance to nearest human development (dist2dev) and both linear (day) and quadratic (day^2) trends through the study period. Due to low sample sizes, we constrained the number of variables that we included in one model. However, because the sampling occurred in a pilot year, we wanted to investigate a variety of variables. As a way to balance these two objectives, we allowed no model to have more than six parameters. To accomplish this, we needed to find the best variable to represent nest placement and pinyon jay density. We ran all possible models with six or less variables, with no variables in the same variable group (e.g., nest placement, pinyon jay abundance) occurring in the same model, and summed the model weights for each of the competing variables. We found that NestHt best represented nest placement and PIJAcnt best represented pinyon jay abundance. We modeled only additive effects. For the quadratic effect we used day^2 along with day; we did not consider models that contained day^2 only because they are unrealistic for these data. This approach resulted in a total of 43 models fit for the final analysis. Fledging success For the fledging success analysis, we used an identical approach as the hatching success. The main difference was that preliminary modeling indicated that TreeHt not NestHt best represented nest placement and clustsize not PIJAnt best represented pinyon jay abundance. Colony Site Fidelity Surveys All of the colonies located in 2019 were assessed for site fidelity; two through the intensive nest surveys, and six during a single breeding survey. To investigate site fidelity at known breeding colonies, six of the eight colonies located during grid surveys in 2019 (Figure 2) were re-surveyed with a single survey for 2-3 days during the breeding season in 2020 (April-May). Surveys to determine occupancy of breeding pinyon jays included documenting number of pinyon jays at a colony, behaviors observed, and location of old and new nests. Both morning and evening surveys were conducted. 12 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Figure 2. Location of six additional pinyon jay colonies surveyed in 2020 to assess site fidelity within Colorado. 13 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Results: Intensive Colony Surveys A total of 74 new nests and a total of 188 old nests were located within the six colonies (Table 1; Figures 3-8). New nests included those that were being constructed though they may not have been subsequently used, nests with an incubating female, and nests with eggs or nestlings. The earliest date we found birds partaking in nest construction was 14 February with the first nest with a female incubating located on 28 February 2020. The last nest to fledge young was on 22 May 2020. We had sufficient data to estimate hatching success for 57 nests and fledging success for 43 nests (Table 2). We found the chance of a nest surviving from beginning of incubation to hatch was 56% (95%CI: 40-70%), and for surviving through to a 15 day fledging period (hatch to fledging) was 46% (95%CI: 31-60%; Mayfield 1975). Most nests that did not hatch or fledge were due to predation. Several predators were identified including common raven, great horned owl, and rock squirrel. Five nests were found with eggs that looked to be undisturbed over several nest visits, and thus were considered abandoned. The Transfer Road colony had the highest number of abandoned nests. Two of these nests were initially documented to have a female incubating, however subsequent visits found no female present and eggs still in the nest. We also found one nest at Transfer Road and one at the Smith Mountain colony where a nest was located with a full clutch of eggs, but no female was ever detected incubating. At the Duckett Draw colony, we found a female that initiated incubation, but the nest was found abandoned prior to hatching. The Transfer Road colony had the highest number of instances (three observations) where pairs initiated nest building but never completed the nests. Only at the Shavano Valley colony did we also find one nest in the building stage that was not completed. The Smith Mountain colony had the highest number of nests that fledged young (9 nests fledged young, Table 2). This colony had the fewest number of old nests detected as compared to new nests found (Table 1). Conversely, larger more established colonies (based on number of old nests located) like Shavano Valley, Transfer Road, and Duckett Draw each had lower number of nests that successfully fledged (Table 1 and 2). 14 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Table 1. Number of old and new nests found at the six intensively surveyed colonies and for the six colonies visited to assess site fidelity. # New Colony Nests # Old Nests Beaton Creek* 6 37 Dave Wood* 6 15 Del Norte 4 15 Duckett Draw* 19 84 Glade Park 0 5 Gypsum 1 14 Meeker 3 13 Rangely 0 7 Saguache 2 1 Sawmill Mesa 0 6 Shavano Valley* 19 63 Smith Mountain* 15 9 Transfer Road* 13 81 Total 88 350 *Colonies intensively surveyed 15 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Figure 3. Beaton Creek pinyon jay colony showing new and old nests located in 2020. 16 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Figure 4. Dave Wood pinyon jay colony showing new and old nests located in 2020 17 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Figure 5. Duckett Draw pinyon jay colony showing new and old nests located in 2020. 18 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Figure 6. Shavano Valley pinyon jay colony showing new and old nests located in 2020. 19 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Figure 7. Smith Mountain pinyon jay colony showing new and old nests located in 2020. 20 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Figure 8. Transfer Road pinyon jay colony showing new and old nests located in 2020. 21 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Table 2. Nests located at six pinyon jay colonies in western Colorado where nest fate could be determined in 2020. Female Incubating Nests that Successfully Nests with Nestlings that Colony Nest did not Hatch Hatched Successfully Fledged Beaton Creek 0 2 0 Dave Wood 2 3 0 Duckett Draw 4 9 6 Shavano Valley 4 11 6 Smith Mountain 2 11 9 Transfer Road 5 4 3 Mapped colony spatial extent using both old and new nest locations to define the outer perimeter, varied from 34 to 224 ha across the six intensively surveyed colonies. Distances between active nests within a colony ranged from a minimum distance of 12 m to a maximum distance of 2347 m (Table 3). Table 3. Mapped colony area (old and new nests) and minimum and maximum distance between new nests located during surveys in western Colorado in 2020. Minimum Nest Distance Maximum Nest Distance Colony (m) (m) Colony Area (ha) Beaton Creek 106.80 958.00 43.75 Dave Wood 55.17 915.10 34.88 Duckett Draw 12.21 2347.41 224.60 Shavano Valley 41.98 1808.42 177.06 Smith Mountain 71.03 890.29 38.56 Transfer Road 98.12 2059.37 132.73 The number of pinyon jays counted at colonies ranged from a low of one to a high of 860 (Table 4). Duckett Draw had the highest pinyon jay count, but this did not translate into the colony having a significantly greater number of new nests as compared to the other five colonies. Number of jays counted at colonies declined as the breeding season subsided. We did not find that fledglings remained in the breeding colony for an extended period after fledging. 22 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Table 4. Low and high number of pinyon jays (PIJA) counted during surveys, the dates the counts were taken, mean and median count of pinyon jays at colonies during survey in 2020 in western Colorado. Low PIJA High PIJA Colony Date Count Date Count Median Mean 26 Beaton Creek 4/23/2020 5 4/18/2020 40 25.33 8 Dave Wood 4/21/2020 2 4/3/2020 60 13.9 Duckett Draw 4/29/2020 10 3/4/2020 860 65 139.06 Shavano Valley 5/1/2020 3 3/25/2020 50 26.5 22.68 Smith Mountain 5/3/2020 1 4/20/2020 50 25 18.25 Transfer Road 4/26/2020 10 3/27/2020 110 35 40.34 Cluster Analysis Of the six colonies intensively surveyed (Beaton Creek, Dave Wood, Duckett Draw, Shavano Valley, Smith Mountain, and Transfer Road), two had six clusters (Dave Wood and Duckett Draw), one had four clusters (Smith Mountain), two had three clusters (Beaton Creek and Shavano Valley), and one had two clusters (Transfer Road). The mean number of nests per colony was 76 (Dave Wood had the fewest number of nests — 20, whereas Duckett Draw had the greatest — 100), and the mean number of nests per cluster was 33 (with a range of five nests in one cluster in Smith Mountain, and 59 in Transfer Road). For nests within a cluster, the mean distance between the nearest n – 1 (where n is the number of nests in a colony) neighbors around a focal nest was 718.4 m (with a range of 439.8 m in Beaton Creek to 943.1 m in Duckett Draw). In contrast, this value was 1683.3 m for nests not in a cluster. Therefore, nests in clusters were more than twice as close to neighboring nests than nests not in a cluster. 23 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Figures 12-16. Results from cluster analysis using old and new nests at six pinyon jay colonies in western Colorado in 2020. The different colored nests identify them to a cluster. 24 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 25 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 26 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 27 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 28 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 29 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Nest Success Hatching success Our analysis for hatching success resulted in one model within 1.00 AICc units and six models within 2.00 AICc units of the low-AICc model and 29 models having a lower AICc than the null model (Table 4). The low-AICc model contained a quadratic effect for time (days + days^2) and NestHt. On the logit scale the effect for Days was positive (0.114, 95%CI -0.052 – 0.280) and the effect for Days^2 was negative (-0.003, 95%CI -0.006 - 0.000) resulting in a slight increase then decrease in daily incubation success through the nesting season (Figure 9). The effect of NestHt was negative meaning the higher the nest occurred in a tree, the less chance of successful incubation (-0.181, 95%CI -0.339 - -0.023, Figure 10, Appendix D). The next best hatching success model was 0.21 AICc units higher and included a term for PIJAcnt, with hatching success greater with increasing numbers of pinyon jays counted (0.001, 95%CI -0.001 – 0.004). Estimates for other parameters were similar to the low-AICc model. Fledging success Models for fledging success showed more model selection uncertainty. Six models were within 1.00 AICc units and 13 models were within 2.00 AICc units of the low-AICc model; 28 models had a lower AICc then the null model (Table 5). The low-AICc model included parameters for TreeSp and TreeHt. Nests in pinyon pine trees demonstrated higher fledging success than those located in juniper (logit estimate 0.839, 95%CI 0.250 – 1.928). Regardless of tree species, fledging success decreased with increasing TreeHt (95%CI -0.127, -0.232 0.023, Figure 3). The next best model was 0.12 AICc units higher than the low-AICc model. This model also suggested that nests located in pinyon pine trees had higher fledging success than those in juniper trees (0.914, 95%CI 0.178 – 2.005). Fledging success decreased with increasing TreeHt (-0.115, 95%CI -0.231 – 0.000), and also decreased with increasing Clustsize (-0.022, 95%CI -0.044 – 0.000). It also initially decreased through the season then increased (Days: -0.285, 95%CI -0.639 – 0.070; Days^2: 0.004, 95%CI -0.001 – 0.010). 30 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Table 5. Models fit for incubation success. ∆AICc is the difference between the referenced model and the low-AICc model, k is the number of parameters in the model, w is the model weight. Model Days+Days^2+NestHt Days+Days^2+NestHt+PIJAcnt Days+Days^2+PIJAcnt Days+NestHt Days+Days^2+NestHt+PIJAcnt+Dist2Dev Days+NestHt+PIJAcnt TreeSp+Days+Days^2+NestHt Days+Days^2+NestHt+Dist2Dev Days+Days^2 Days+PIJAcnt PIJAcnt Days+Days^2+PIJAcnt+Dist2Dev NestHt+PIJAcnt Days+NestHt+PIJAcnt+Dist2Dev TreeSp+Days+Days^2+PIJAcnt Days+NestHt+Dist2Dev TreeSp+Days+NestHt Days TreeSp+Days+NestHt+PIJAcnt TreeSp+Days+Days^2 Days+Days^2+Dist2Dev Days+PIJAcnt+Dist2Dev NestHt TreeSp+Days+PIJAcnt PIJAcnt+Dist2Dev TreeSp+PIJAcnt TreeSp+NestHt+PIJAcnt NestHt+PIJAcnt+Dist2Dev TreeSp+Days+NestHt+PIJAcnt+Dist2Dev Null TreeSp+Days+NestHt+Dist2Dev TreeSp+Days Days+Dist2Dev TreeSp+Days+Days^2+Dist2Dev NestHt+Dist2Dev TreeSp+Days+PIJAcnt+Dist2Dev TreeSp+NestHt Dist2Dev TreeSp+PIJAcnt+Dist2Dev TreeSp+NestHt+PIJAcnt+Dist2Dev TreeSp TreeSp+Days+Dist2Dev TreeSp+NestHt+Dist2Dev TreeSp+Dist2Dev AICc 93.04 93.24 94.62 94.74 94.83 94.88 94.98 95.05 95.37 96.03 96.17 96.19 96.23 96.44 96.50 96.74 96.74 96.79 96.92 97.36 97.40 97.69 97.80 98.06 98.16 98.20 98.23 98.24 98.48 98.50 98.72 98.75 98.81 99.40 99.45 99.72 99.82 100.11 100.19 100.26 100.45 100.78 101.48 102.10 ∆AICc 0.00 0.21 1.58 1.71 1.79 1.85 1.95 2.02 2.33 3.00 3.14 3.15 3.19 3.40 3.46 3.70 3.71 3.75 3.88 4.33 4.36 4.66 4.77 5.03 5.12 5.16 5.20 5.20 5.44 5.46 5.68 5.71 5.78 6.36 6.41 6.68 6.78 7.08 7.15 7.23 7.42 7.74 8.44 9.07 k w 4 5 4 3 6 4 5 5 3 3 2 5 3 5 5 4 4 2 5 4 4 4 2 4 3 3 4 4 6 1 5 3 3 5 3 5 3 2 4 5 2 4 4 3 0.13 0.12 0.06 0.05 0.05 0.05 0.05 0.05 0.04 0.03 0.03 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 31 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Table 6. Models fit for fledging success. ∆AICc is the difference between the referenced model and the lowAICc model, k is the number of parameters in the model, w is the model weight. Model TreeSp+TreeHt TreeSp+Days+Days^2+TreeHt+ClustSize TreeSp+TreeHt+ClustSize TreeHt TreeHt+ClustSize TreeHt+Dist2Dev TreeSp+TreeHt+Dist2Dev Days+Days^2+TreeHt+ClustSize TreeSp+Days+Days^2+TreeHt TreeSp+TreeHt+ClustSize+Dist2Dev Dist2Dev TreeHt+ClustSize+Dist2Dev Days+Days^2+ClustSize TreeSp+Days+TreeHt TreeSp+Days+Days^2+ClustSize TreeSp+Days+TreeHt+ClustSize Days+Days^2+ClustSize+Dist2Dev ClustSize+Dist2Dev Days+Days^2+TreeHt+Dist2Dev ClustSize Days+TreeHt Days+Days^2+TreeHt Days+TreeHt+ClustSize Days+TreeHt+Dist2Dev Days+Days^2+Dist2Dev TreeSp+Days+DistTrunk+TreeHt+ClustSize TreeSp+Days+TreeHt+Dist2Dev TreeSp+Dist2Dev Null TreeSp+ClustSize TreeSp+ClustSize+Dist2Dev Days+TreeHt+ClustSize+Dist2Dev Days+Dist2Dev TreeSp TreeSp+Days+Days^2+Dist2Dev Days+Days^2 Days+ClustSize Days+ClustSize+Dist2Dev TreeSp+Days+Days^2 Days TreeSp+Days+Dist2Dev TreeSp+Days+ClustSize TreeSp+Days TreeSp+Days+ClustSize+Dist2Dev AICc 112.81 112.94 113.24 113.36 113.64 113.70 113.77 113.94 114.46 114.48 114.56 114.62 114.67 114.76 114.84 114.99 115.08 115.23 115.23 115.29 115.34 115.42 115.48 115.61 115.65 115.67 115.68 115.71 115.82 116.02 116.12 116.42 116.48 116.54 116.62 116.99 117.24 117.24 117.27 117.44 117.58 117.97 118.13 118.13 ∆AICc 0.00 0.13 0.43 0.55 0.84 0.90 0.97 1.14 1.65 1.67 1.75 1.81 1.86 1.95 2.03 2.18 2.27 2.42 2.42 2.48 2.53 2.61 2.67 2.80 2.84 2.87 2.87 2.90 3.02 3.21 3.31 3.61 3.67 3.73 3.81 4.18 4.43 4.43 4.46 4.63 4.77 5.16 5.32 5.32 k w 3 6 4 2 3 3 4 5 5 5 2 4 4 4 5 5 5 3 5 2 3 4 4 4 4 6 5 3 1 3 4 5 3 2 5 3 3 4 4 2 4 4 3 5 0.07 0.06 0.06 0.05 0.05 0.04 0.04 0.04 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00 0.00 32 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Figure 9. Daily incubation success by date at average nest height of 2.03 m. 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 Figure 10. Daily incubation success by nest height on 4/10/2020. 1 0.95 0.9 0.85 0.8 0.75 0.7 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Nest Ht (ft) 33 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Figure 11. Fledging success for a 15-day fledgling period for pinyon pine and juniper trees, varying by tree height. 1 0.9 Prob. of Fledging 0.8 0.7 0.6 0.5 Pinyon 0.4 Juniper 0.3 0.2 0.1 0 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Tree Ht (ft) Colony Site Fidelity Surveys The eight colonies found during the 2019 grid surveys were revisited to assess site fidelity. Two of the colonies, Smith Mountain and Transfer Road, were assessed during the intensive colony surveys. At the remaining six sites we found three of the colonies (Gypsum, Meeker, and Saguache) had new nests and pinyon jays present (Table 1). At the Glade Park colony, observers saw adults feeding recently fledged young but no new nests were located. At the Rangely colony, birds were observed but no new nests were located and at the Sawmill Mesa colony, no pinyon jay activity was detected. 34 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Discussion: Pinyon jays are a highly mobile species that wander widely in fall and winter, taking advantage of a diversity of habitat types across a range of elevations. Annual home range size is variable and has been estimated to fluctuate from 1600 to 6400 ha (Johnson and Balda 2020). The annual area used by pinyon jays is likely dependent on the individual flock size as well as habitat quality and pinyon pine mast crop availability (Johnson and Balda 2020). The size of a flock, age composition, and home range size are found to be most consistent from year to year when birds associate into breeding colonies (Marzluff and Balda 1992). Owing to the complexities of researching such a wide-ranging, nomadic species, we targeted our survey efforts during the single biological period when bird numbers and movements are most fixed. By examining birds during the breeding season, we hoped to better understand colony size and structure, flock size and nest density, identify important factors that may impact nesting and fledging success, and assess site fidelity. Due to the precipitous population declines thought to be occurring across the species’ range, it was important for CPW to begin to establish baseline data for pinyon jays in Colorado with the long-term goal of developing a protocol to monitor their population status through time and to address conservation actions needed to help stop the population decline. During this study we mapped both old and new nests located at colonies to calculate individual colony size and assess colony structure based on clustering of nests in a colony area. The six colonies varied in area covered ranging from 34-224 ha. Distances among new nests found within colony boundaries were irregular with the nearest neighbor nests being a mere 12 m apart to nests being placed over 2300 m apart. Marzluff and Blada (1992) found over a 14-year period from 1973-1987, that colonies covered an area of around 100 ha with the average colony containing 11 nests (2-32 nests), arranged anywhere from 10-600 m apart. In New Mexico, colony breeding area has been measured to range from 2.67-60.32 ha (Johnson and Balda 2020). The size discrepancies measured in different studies may be attributed to how colony area estimates were derived, whether old nests as well as new nests were included in estimates, and how colony boundaries are defined (e.g. once a specified distance between nests is reached, does the area become defined as a new colony?). We did find that in colonies there are definite clustering of nests and that the numbers of clusters and number of nests in a cluster is variable. This clustering could identify hot spots for nesting and it may useful in future habitat assessments to help decipher nesting preference in a colony. Importantly, identifying these clusters may impact how colonies are defined. To assist with consistency and management recommendations across the range, is imperative for researchers and managers working on pinyon jays to understand and define a colony boundary using the same framework. 35 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 From our work, we would advocate that it is imperative to include not only new nests, but also old nest locations in colony area estimates to account for how colony boundaries may ebb and flow across the landscape over time. This time lapse mapping is necessary to inform managers about potential impacts of habitat treatments and to identify the entirety of conservation areas. We also think that understanding the structure of colonies by identifying clusters of nests should be considered in order to agree on a clear definition of what a pinyon jay colony is. Not unlike studies completed in Arizona in the 1980’s (Marzluff and Balda 1988 and 1992), pinyon jay hatching and fledging success in Colorado was very much dependent on escaping predation. Marzluff (1988) estimated for 282 nests over a six-year period that a mere 27% of pinyon jay nests produced fledged young with close to 50% of those not fledging young being predated. The remaining 23% of the nests they measured failed due to weather events (snow and wind) or were abandoned. We found the chance of a pair to fledge young was 46% with most nests failing due to predation and the remaining being abandoned. The Smith Mountain colony had the greatest number of nests that successfully produced fledglings with nine nests that successfully fledged. This colony is located in a roadless area descending into the Black Canyon of the Gunnison River landscape. It is isolated from human disturbance as it occurs > 4 km from residential areas and lacks any recreational access by vehicles or hikers. In addition, it appeared to be a newer colony with very few old nests located. The original Smith Mountain colony detected during grid surveys in 2019, was approximately 2.4 km from the nesting area discovered in 2020. The recent occupation of this colony in an unused woodland may have resulted in lower predation rates, as predators would be naïve to the new potential food resource. All of the other colonies we assessed were located adjacent to residential communities and agricultural lands. A reduced reproductive output at colonies located near urban interfaces could potentially be attributed to an increase in prolific urban predators such as common ravens and great horned owls. In addition, human activity may interrupt nesting. Human disturbances noted at colony sites were target shooting, dumping of trash and animal carcasses, and recreational pressure from hikers, off road vehicles, and dog walkers. We found that hatching success was higher for nests placed lower in trees (Appendix D). This is probably because lower nests are covered by denser foliage providing greater concealment from predators. Higher nests may be more easily located by aerial predators as well as being more easily accessible once discovered. Similarly, fledging success was higher in shorter trees. These short stature trees are generally younger in age class and may have higher branch and twig density for greater concealment from predators. Johnson et al. (2015) found that pinyon jays avoided nesting in large, old pinyon and juniper 36 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 trees as these trees had more open growth patterns providing less cover and protection for a nest. Pinyonjuniper woodland vegetation treatments often select these smaller trees for removal especially when they are encroaching into sagebrush landscapes. With the ability to identify potential nesting trees within pinyon jay colonies, managers can better identify the impacts habitat treatments may have on nesting pinyon jays. Colonial nesting in birds has been thought to have evolved for two main reasons: 1) to efficiently exploit food resources and/or 2) as a means to avoid high rates of predation (Kopachena 1991). Our results for hatching success tended to support the idea of antipredator protection as hatching success increased with pinyon jay abundance. This may have been due to increased mobbing behavior and vigilance while a female remained on her nest to incubate. However, as nestlings grow and the female pinyon jay begins to leave the nest unattended, raucous jays may inadvertently alert predators to a colony area putting nestlings in jeopardy when no female is on the nest. Our data provided evidence of this with nests in larger, tight knit clusters having reduced fledging success. Clustered nests may have had more pinyon jay activity as adults and helpers provisioned young, attracting potential predators. The resulting impact of a nest being detected in a cluster, was that other nests in the cluster may also be more easily discovered and subsequently predated. Marzluff and Balda (1992) found that large colonies with greater clumping of nests, experienced higher predation than small, colonies with more dispersed nests. In addition, they found that nests in close proximity to a neighboring nest that was preyed upon commonly suffered the same fate, and nests in the center of the colony versus the edge had higher predation rates. Pinyon jays likely attain both costs and benefits for nesting in colonies with regards to predation. Therefore, the colonial nature of pinyon jays may have evolved not to necessarily to reduce predation, but as a selective strategy to work cooperatively to store a reliable food cache that the colony can access for breeding, and to nest near areas where insects can be readily collected. Pinyon jays did appear to have high site fidelity to the colonies we revisited; however, at two of the colonies we assessed for site fidelity, we were not able to find any new nests or presence of fledglings. Colonies are known to move, and we may not have been able to accurately evaluate movement with our limited efforts in 2020. Peterson et al. (2014) stated that a search radius around a colony of 500 m is a reasonable distance to find a colony that has moved. However, our Smith Mountain colony shifted in location by approximately 2.4 km from the original location found in 2019; we were never able to locate birds actively nesting in the original colony area. In addition, in the colonies we intensively evaluated, we found new nests positioned > 2000 m apart. Thus in Colorado, limiting a search radius to 500 m beyond 37 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 known nests may not be sufficient to adequately assess pinyon jay colony use. In the future to improve our ability to assess colony site fidelity, we will not constrain our search area and we will incorporate multiple day surveys with a minimum of three sampling efforts within the breeding season window. This intensive survey effort at breeding pinyon jay colonies was the first ever completed in Colorado. The information garnered was particularly important in assessing potential colony extent and structure, importance of nest tree stature, site fidelity and identifying potential threats to hatching and fledging success. This project is ongoing with additional surveys to be completed in 2021, and a final report including management recommendations finalized by April 2022. Plans for 2021 Surveys: 1. A crew will do intensive nest monitoring (mid-February to mid-May) replicating the 2020 surveys at six colonies: Duckett Draw, Shavano Valley, Smith Mountain, Beaton Creek, Dave wood and Transfer Road. 2. We will revisit colonies located during grid surveys conducted in 2019 and 2020. We will survey 13 of these colonies across a variety of habitat types and elevations. Each colony will be visited three times during the breeding season (mid-February to mid-May). During each visit two surveyors will evaluate the colony over three days incorporating both morning and evening surveys. Protocols will follow the intensive survey efforts to accurately map old and new nests, define colony extent, record behaviors, evaluate nest trees and placement of nests in trees, estimate number of pinyon jays in a colony, count potential predators and assess potential threats. Information gained from this effort will aid in our understanding of variability in pinyon jay colonies across Colorado. 38 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Literature Cited: Boone, J.D. E. Ammon, and K.Johnson. Long-term declines in the pinyon jay and management implications for piñon-juniper woodlands. s, in Trends and traditions: Avifaunal change in western North America (W. D. Shuford, R. E. Gill Jr., and C. M. Handel, eds.), pp. 190–197. Studies of Western Birds 3. Western Field Ornithologists, Camarillo, CA; doi 10.21199/SWB3.10. Burnham, K.P. and D.R. Anderson. 2001. Kullback-Leibler information as a basis for strong inference in ecological studies. Wildlife Research. 28 (2): 11-119. Calenge, C. 2006. The package “adehabitat” for the R software: a tool for the analysis of space and habitat use by animals. Ecological Modelling. 197 (3-4): 516-519. Charrad, M. N. Ghazzali, V. Boiteau, and A. Niknafs. 2014. NbClust: an R package for determining the relevant number of clusters in a data set. Journal of Statistical Software. 61(06): 1-36. Colorado Parks and Wildlife. 2015. State Wildlife Action Plan: Prepared for the citizens of Colorado and Its Visitors by Colorado Parks and Wildlife. Denver, CO. cpw.state.co.us. Daubenmire, R. F. 1943. Vegetational zonation in the Rocky Mountains. Botanical Review 9(6):325-393. Gori, D., and J. Bate. 2007. Historical range of variation and state and transition modeling of historical and current landscape conditions for montane grassland for the southwestern U.S. Prepared for the USDA Forest Service, Southwestern Region by The Nature Conservancy, Tuscon, AZ. 21pp. http://azconservation.org/projects/ southwest_forest_assessment. Gottfried, G. J., T. J. Swetnam, C. D. Allen, J. L. Betancourt, and A. L. Chung-MacCoubrey. 1995. Pinyonjuniper woodlands. Pages 95-132 in D. M. Finch and J. A. Tainter, editors. Ecology, diversity, and sustainability of the middle Rio Grande basin. General Technical Report RM-268. USDA Forest Service, Fort Collins, Colorado, USA. Johnson, K., L. Wickersham, J. Smith, N. Petersen, and J. Wickersham (2015). Nest-scale habitat use by Pinyon Jay and Gray Vireo in the BLM Farmington resource area 2013–2014. Natural Heritage New Mexico Report 15-GTR-386. University of New Mexico, Albuquerque, NM, USA. https://nhnm.unm.edu/sites/default/files/nonsensitive/publications//FINAL%202014%20BLM% 20P-J%20%20report.pdf. 39 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Johnson, K., T. B. Neville, J. W. Smith, and M. W. Horner. 2016. Home range- and colony-scale habitat models for Pinyon Jays in piñon-juniper woodlands of New Mexico, USA. Avian Conservation and Ecology 11(2):6.http://dx.doi.org/10.5751/ACE-00890-110206. Johnson, K., and G. Sadoti (2019). Model transferability and implications for woodland management: a case study of Pinyon Jay nesting habitat. Avian Conservation and Ecology 14. https://doi.org/10.5751/ace-01467-140217. Johnson, K. and R. P. Balda (2020). Pinyon Jay (Gymnorhinus cyanocephalus), version 2.0. In Birds of the World (P. G. Rodewald and B. K. Keeney, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.pinjay.02. Kopachena, J.G. 1991. Food dispersion, predation, and the relative advantage of colonial nesting. Colonial Waterbirds. 14(1): 7-12. K. V. Rosenberg, J. A. Kennedy, R. Dettmers, R. P. Ford, D. Reynolds, J.D. Alexander, C. J. Beardmore, P. J. Blancher, R. E. Bogart, G. S. Butcher, A. F. Camfield, A. Couturier, D. W. Demarest, W. E. Easton, J.J. Giocomo, R.H. Keller, A. E. Mini, A. O. Panjabi, D. N. Pashley, T. D. Rich, J. M. Ruth, H. Stabins, J. Stanton, T. Will. 2016. Partners in Flight Landbird Conservation Plan: 2016 Revision for Canada and Continental United States. Partners in Flight Science Committee. 119 pp. Ligon, J.D. 1978. Reproductive interdependence of pinyon jay and pinyon pines. Ecological Monographs. 48.111-126. Marzluff, J. M. (1988). Do Pinyon Jays alter nest placement based on prior experience? Animal Behaviour 36:1–10. Marzluff, J. M., and R. P. Balda (1992). The Pinyon Jay: Behavioral Ecology of a Colonial and Cooperative Corvid. T. & A. D. Poyser, London, United Kingdom. Mayfield, H.F. 1975. Suggestions for calculating nest success. The Wilson Bulletin. 87 (4): 456-466. Petersen, N., Johnson, K., and J. Smith. 2014. Pinyon Jay Monitoring Program for New Mexico. Natural Heritage New Mexico Publication GTR-14-382. Biology Department, University of New Mexico, Albuquerque, NM. Scrucca, L., M. Flop, B. Murphy, and A.E. Raftery. 2016. Mclust 5: clustering, classification and density estimation using Gaussian Finite Mixture Models. R J. 2016 Aug; 8(1): 289–317. Wiggins, D.A. (2005, September 5). Pinyon Jay (Gymnorhinus cyanocephalus): a technical conservation assessment. [Online]. USDA Forest Service, Rocky Mountain Region. Available: http://www.fs.fed.us/r2/projects/scp/assessments/pinyonjay.pdf. 40 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Appendix A. Photos of Colonies (All colony photos were taken by Amy Sullivan) Beaton Creek Colony in foreground adjacent to urban interface. 41 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Dave Wood Colony 42 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Duckett Draw Colony 43 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Shavano Valley Colony 44 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Smith Mountain Colony 45 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Transfer Road Colony 46 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Appendix B. Examples of females on nests (Photos taken by Shawn Conner and Aaron Yappert). 47 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 48 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Appendix C. Examples of predation seen at nests. Torn apart nest; likely rock squirrel predation 49 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 Eggs broken and pecked; likely jay spps. predation Dismemebered nestling; likely great horned owl predation Appendix D. Examples of pinyon jay nest trees. 50 ��Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 52 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 53 �Pinyon Jay Breeding Colony Summary Assessment Colorado Parks and Wildlife 2021 54 � Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Reports Text A resource consisting primarily of words for reading. Examples include books, letters, dissertations, poems, newspapers, articles, archives of mailing lists. Note that facsimiles or images of texts are still of the genre Text. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Pinyon jay breeding colony summary investigation Southwest Colorado 2020 Description An account of the resource Pinyon jays (<em>Gymnorhinus cyanocephalus</em>) are thought to be declining range-wide (Boone et al. 2018). Very little is known about their breeding status and habitat use in Colorado. In 2020, Colorado Parks and Wildlife examined six breeding colonies in Montrose and Delta counties to assess colony size and structure, hatching and fledging success, potential threats to reproductive output, and colony site fidelity. Six additional colonies located in western Colorado in 2019 were surveyed a single time during the breeding season to determine site fidelity. Creator An entity primarily responsible for making the resource Seglund, Amy Rossi, Liza Runge, Jon Flenner, Michelle Aagaard, Kevin Subject The topic of the resource Pinyon jays <em>Gymnorhinus cyanocephalus</em> Breeding status Habitat Southwest Colorado Extent The size or duration of the resource. 54 pages Date Created Date of creation of the resource. 2021 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