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Background: Information on reproduction of harvested species such as mule deer (Odocoileus hemionus) is vital for conservation and management. Furthermore, parturition in ungulates may be detected using patterns of movement logged by GPS transmitters. Several movement-based methods have been developed to detect parturition in ungulates including the Peterson method, behavioral change point analysis (BCPA), rolling minimum convex polygons (rMCP), individual-based method (IBM), and population-based method (PBM). Our objectives were to (1) test the accuracy and the precision of each previously described method and (2) develop an improved method optimized for mule deer that incorporated aspects of the other methods. Methods: We determined parturition timing and status for female mule deer fitted with GPS collars and implanted with vaginal implant transmitters (VITs). We used movement patterns before and after parturition to set movement thresholds for each movement-based method. Following model training, we used location and birth date data from an external dataset to test the effectiveness of each movement-based method. Additionally, we developed a novel method for detecting parturition called the analysis of parturition indicators (API). We used two regression analyses to determine the accuracy and precision of estimates generated by each method. Results: The six methods we employed varied in accuracy, with the API, rMCP, and BCPA being most accurate. Precision also varied among methods, with the API, rMCP, and PBM generating the most precise estimates of parturition dates. The API and the rMCP performed similarly and better overall than any of the other existing methods. Conclusions: We found that movement-based methods could be used to accurately and precisely detect parturition in mule deer. Further, we determined that the API and rMCP methods had the greatest overall success at detecting parturition in mule deer. The relative success of the API and rMCP may be attributed to the fact that both methods use home range size to detect parturition and are validated using known parturition dates of collared deer. We present the API as an efficient method of estimating birth status and timing of parturition of mule deer fitted with GPS transmitters, as well as affirm the effectiveness of a previously developed method, rMCP. [ABSTRACT FROM AUTHOR]

Ungulates often alter behavior and space use in response to interspecific competition. Despite observable changes in behavior caused by competitive interactions, research describing the effects of competition on survival or growth is lacking. We used spatial modeling to determine if habitat use by female mule deer (Odocoileus hemionus) was affected by other ungulate species prior to, during, and after parturition. We conducted our study in the Book Cliffs region of eastern Utah, USA, during 2019 and 2020. We used resource selection function (RSF) analysis to model space use of 4 ungulate species that potentially competed with mule deer: bison (Bos bison), cattle, elk (Cervus canadensis), and feral horses. We incorporated RSF models for competing species into a random forest analysis to determine if space use by mule deer was influenced by these other ungulate species. We used survival and growth data from neonate mule deer to directly assess potential negative effects of other ungulates. Habitat use by elk was an important variable in predicting use locations of mule deer during birthing and rearing. The relationship was positive, suggesting interference competition was not occurring. Survival of neonate mule deer increased as the probability of use by elk increased (hazard ratio = 0.185 ± 0.497 [SE]). Further, probability of use by elk in rearing habitat had no influence on growth of neonate mule deer from birth to 6 months of age, suggesting that exploitative competition was not occurring. [ABSTRACT FROM AUTHOR]

The capture of neonate ungulates allows for the collection of valuable ecological data, including estimates of litter size. However, varied methods used to capture neonate ungulates can result in sampling biases. Our objective was to determine if opportunistic captures of neonate ungulates (i.e., locating neonates by visually scanning for adult females displaying postpartum behaviors) bias relative estimates of litter size and investigate potential causes if a bias does exist. We analyzed data from 161 litters of mule deer (Odocoileus hemionus) sampled using three different capture methods during 2019–2021 in Utah, USA. Estimates of litter size derived from opportunistic captures were smaller than estimates derived from movement-based captures or captures completed with the aid of vaginal implant transmitters (VITs). Age at capture was inversely related to estimates of litter size and likely influenced the detection bias associated with opportunistic captures. Neonates captured opportunistically were not older than neonates captured using movement-based methods, but were older than neonates captured with the aid of VITs. Distance between neonates from the same litter did not influence estimates of litter size. Researchers should be aware of the biases associated with different capture methods and use caution when interpreting data among multiple capture methods. Estimates of litter size derived from opportunistic captures should not be compared to estimates of litter size derived from alternative capture methods without accounting for the detection bias we observed. [ABSTRACT FROM AUTHOR]

Ecological context—the biotic and abiotic environment, along with its influence on population mixing dynamics and individual susceptibility—is thought to have major bearing on epidemic outcomes. However, direct comparisons of wildlife disease events in contrasting ecological contexts are often confounded by concurrent differences in host genetics, exposure histories, or pathogen strains. Here, we compare disease dynamics of a Mycoplasma ovipneumoniae spillover event that affected bighorn sheep populations in two contrasting ecological contexts. One event occurred on the herd's home range near the Rio Grande Gorge in New Mexico, while the other occurred in a captive facility at Hardware Ranch in Utah. While data collection regimens varied, general patterns of antibody signal strength and symptom emergence were conserved between the two sites. Symptoms appeared in the captive setting an average of 12.9 days postexposure, average time to seroconversion was 24.9 days, and clinical signs peaked at approximately 36 days postinfection. These patterns were consistent with serological testing and subsequent declines in symptom intensity in the free‐ranging herd. At the captive site, older animals exhibited more severe declines in body condition and loin thickness, higher symptom burdens, and slower antibody response to the pathogen than younger animals. Younger animals were more likely than older animals to clear infection by the time of sampling at both sites. The patterns presented here suggest that environment may not be a major determinant of epidemiological outcomes in the bighorn sheep—M. ovipneumoniae system, elevating the possibility that host‐ or pathogen‐factors may be responsible for observed variation. [ABSTRACT FROM AUTHOR]

Hunting pressure alters the spatial ecology of many ungulate species. During hunting periods, game species often select areas that have reduced hunter accessibility by increasing use of forest cover, remaining farther from roads, or moving to private land as a means of refuge. Our objectives were to determine if elk (Cervus canadensis) in central Utah, USA, shifted distribution towards areas of refuge (private land) in response to hunting and whether allocating hunting permits to refuge areas could reduce selection of refugia by elk. We captured 445 elk between January 2015 and March 2017 on the Wasatch Front in central Utah and fitted each individual with a global positioning system collar. We used logistic regression models and Bayesian change point analyses to determine differences in daily use of public land in response to the addition of private‐land hunting. We detected shifts in elk distribution at the beginning of the archery hunting season and during the rifle season, suggesting elk selected for private land as refuge from hunters. At the conclusion of the hunting season, we detected a shift back to public land. The addition of private‐land hunting increased use of public land by elk during the rifle season (from 29% in 2015 to 41% in 2016). Our results show that the distribution of elk across a matrix of public and private land can be influenced by manipulating hunting pressure. Hunter access, the ability of hunters to access target game species, can be a concern in areas with private‐land refuges. This can be particularly problematic when management strategies rely on hunter harvest to maintain population objectives; however, this problem can be mitigated by the introduction of hunting on private lands, if landowners provide hunter access. [ABSTRACT FROM AUTHOR]

Background: Conservation and management of migratory animals has gained attention in recent years, but the majority of research has focused on stereotypical 'migrant' and 'resident' behaviors, often failing to incorporate any atypical behaviors or characterize migratory behaviors beyond distance and timing of the migration. With migration threatened by anthropogenic development and climate change, it is crucial that we understand the full range of migratory behaviors. Our objective was to demonstrate and characterize the variation in migration strategies, including typical and atypical migratory behaviors for mule deer (Odocoileus hemionus) in Utah, USA. Methods: Because calculation of common metrics such as distance, timing, and use of stopovers during migration did not adequately describe the variation we observed in migratory behavior for this species—particularly when animals visited multiple (> 3) ranges for extended lengths of time—we developed additional methods and categories to describe observed variation in migratory behavior. We first categorized trajectories based on the number of discrete, separate ranges and range shifts between them. Then, we further characterized the variation in migration strategies by examining the timing, duration, and distance traveled within each of the categories. We also examined if and how frequently individual deer switched among categories from year to year. Results: We classified 1218 movement trajectories from 722 adult female mule deer, and found that 54.4% were dual-range migrants, who made one round-trip to one distinct range. Multi-range migrants (23.6%) made one round-trip during which they stayed at multiple discrete ranges. Commuters (1.0%) traveled to the same range multiple times, and poly migrants (1.5%) made multiple round-trips to different ranges. Gradual movers (2.5%) did not show a discrete range shift but moved gradually between ranges, whereas residents (12.6%) never left their home ranges, and dispersers (4.4%) left but never returned. Of the deer that we monitored for multiple years, 51.2% switched among categories. Conclusion: We conclude that the substantial number of atypical migratory strategies, as well as the number of deer that switched categories, underlines the importance of studying these less-stereotyped behaviors that may be exhibited by large proportions of populations. Acknowledging and investigating the full complexity and diversity in migratory strategies might uncover unknowns with respect to underlying factors and drivers of migration, and can help shape effective conservation strategies. [ABSTRACT FROM AUTHOR]

The size of animal populations fluctuates with number of births, rate of immigration, rate of emigration, and number of deaths. For many ungulate populations, adult female survival is the most important factor influencing population growth. Therefore, increased understanding of survival and causes of mortality for adult females is fundamental for conservation and management. The objectives of our study were to quantify survival rates of female elk (Cervus canadensis) and determine cause‐specific mortality. We predicted that hunter harvest would be the leading cause of mortality. Further, we predicted that hunters would harvest animals that were in prime age (2–9 yr) and in better condition than elk predated by mountain lions (Puma concolor). From 2015 to 2017, we captured 376 female elk in central Utah, USA. We assessed body size and condition of captured elk, fitted each animal with a global positioning system‐collar, and determined cause of death when we received mortality signals. We estimated survival using Kaplan‐Meier estimates and Cox proportional hazard models within an Akaike's Information Criterion model selection framework to identify covariates that influenced survival. We analyzed differences in size and condition measurements between harvested elk and predated elk using analysis of variance tests. Our best model indicated consistent survival across years; mean survival was 78.3 ± 3.5% (SE) including hunter harvest and 95.5 ± 1.7% without hunter harvest. In decreasing order of importance, elk mortality occurred from hunter harvest (21.2%), mountain lion predation (3.7%), depredation removal (0.5%), automobile collision (0.3%), disease (0.3%), complications during calving (0.3%), and those characterized as undetermined (1.3%). Neck circumference and body length were negatively associated with survival, suggesting that larger animals in good condition had lower survival as a result of hunter harvest. Individuals that died because of cougar predation were smaller and had less loin muscle than the average animal. Hunters removed large, healthy, prime‐aged females, individuals that likely have a greater effect on population growth than elk lost to other predators. If the proportion of larger, healthy females in the population begins to decline, hunting practices may require adjustment because hunters may be removing individuals with the greatest reproductive value. © 2021 The Wildlife Society. Results of our study highlight differential selection of elk by human hunters compared to mountain lions. Predated elk were smaller and in worse condition than those lost to hunters, who primarily selected large, healthy females. [ABSTRACT FROM AUTHOR]

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Pressure from hunting can alter the behavior and habitat selection of game species. During hunting periods, cervids such as elk (Cervus canadensis) typically select for areas further from roads and closer to tree cover, while altering the timing of their daily activities to avoid hunters. Our objective was to determine the habitat characteristics most influential in predicting harvest risk of elk. We captured 373 female elk between January 2015 and March 2017 in the Uinta-Wasatch-Cache National Forest and surrounding area of central Utah, USA. We determined habitat selection during the hunting season using a resource selection function (RSF) for 255 adult cow elk. Additionally, we used a generalized linear mixed model to evaluate risk of harvest based on habitat use within home ranges (3rd order selection) as well as the location of the home range on the landscape to evaluate vulnerability on a broader scale. Female elk selected for areas that reduced hunter access (rugged terrain, within tree cover, on private land). Age, elevation and distance to roads within a home range were most influential in predicting harvest risk (top model accounted for 36.2% of AIC weight). Elevation and distance to trees were most influential in predicting risk when evaluating the location of the home range (top model accounted for 42.1% of AIC weight). Vulnerability to harvest was associated with proximity to roads. Additionally, survival in our landscape decreased with age of femaleelk. [ABSTRACT FROM AUTHOR]

Capture techniques to deploy radio‐collars often risk mortality and injury to the animal. Capture‐induced mortality can affect population sizes but also introduces bias in survival estimates based on data from captured animals. In recent years, a large‐scale research and monitoring project in Utah, USA, has involved capturing and radio‐collaring hundreds of mule deer (Odocoileus hemionus), a species of great interest in large parts of North America. Our objective was to investigate how the survival rates of these mule deer were affected by capture and handling. During winters of 2014–2018, an experienced capture crew net‐gunned and fitted 1,805 animals with global positioning system (GPS)‐collars. We estimated survival rates during the first 6 weeks after capture using Cox proportional hazard regression, and compared the survival rates of animals that were captured in a particular year to those of animals that were not captured but fitted with a GPS‐collar in a previous year. We used a model selection framework to evaluate how long survival rates of captured animals were different from those of animals that were not captured. Our results indicated that weekly survival rates of captured animals were 0.985 ± 0.003 (SE), 0.988 ± 0.002, and 0.990 ± 0.001 in weeks 1, 2 and 3, respectively. Weekly survival rates of captured deer during weeks 4–6 were 0.993 ± 0.001, the same as those of deer that were not captured at the same time. Furthermore, post‐capture survival rates were positively influenced by body size and negatively influenced by age. We conclude that the mortality resulting from helicopter capture was low but recommend comparing newly captured and previously captured individuals to examine what proportion of observed mortality is likely capture‐related. © 2020 The Wildlife Society. Captured deer had higher mortality rates than non‐captured deer for 3 weeks following capture and survival rates of captured deer were negatively affected by age and positively affected by body mass. We recommend either spreading capture efforts over multiple years, so that it is possible to make comparisons between newly captured and previously captured individuals and examine what proportion of observed mortality is likely capture‐related, or excluding the initial 3 weeks after capture from analysis entirely. [ABSTRACT FROM AUTHOR]

Climatic changes are affecting the distribution and viability of species worldwide, and the effects may be greatest for heat-sensitive organisms in populations situated near the species' equatorial range limit. We studied the population dynamics of a cold-adapted large herbivore, moose (Alces alces shirasi), in a population located at the extreme southern range limit of the species in Utah, USA, using a longterm dataset of aerial counts conducted between 1958 and 2013. We used a modeling approach that acknowledges the uncertainty in the number of moose counted. To determine how climate influenced this population, we tested four models corresponding to different hypotheses suggested by previous studies of moose population dynamics: (1) High summer rainfall increases population growth, (2) severe winters reduce population growth, (3) high summer and winter temperatures cause heat stress which reduces population growth, and (4) snow conditions favorable to winter ticks reduce population growth. We then ranked these models against two additional hypotheses that tested the combined effects of the bestperforming models. The best-supported model included summer rainfall and the number of days with snow cover in late winter, which described the conditions influencing winter tick numbers, a common parasite of moose in the region. Reproductive female ticks drop off their hosts at the end of winter to lay eggs, and fewer ticks survive in years with abundant snow cover. Positive effects of snow and rainfall indicated that moose population growth was higher following summers with more rainfall and late winters with more days of snow cover, the latter because those conditions likely reduced winter tick numbers. In accordance with global patterns in which altered precipitation regimes are influencing the dynamics of many species, the top-performing model suggested that both summer and winter precipitation acted together to explain the most variation in moose population growth. Our analysis demonstrates the multiple pathways by which climate and population density can affect the dynamics of temperate species living at their equatorial range limits, including potential parasite-mediated effects. [ABSTRACT FROM AUTHOR]

Land managers regularly use temporal nest protections to reduce the likelihood of raptor nest disturbance or abandonment, but guidelines are not consistent across management boundaries. We assessed alternative nest use (i.e., egg-laying) and nest spacing at 28 Golden Eagle ( Aquila chrysaetos) territories that were monitored ≥25 yr between 1976 and 2013 (all except seven territories were monitored annually without interruption). Territories contained 1-8 nests ( x¯ = 2.9), and average spacing between alternative nests was 0.5 km. Inspection of 21 territories monitored for 26-38 yr without interruption suggested eagles used individual nests an average of every 3.3 yr, laid eggs in any nest within territories an average of every 1.8 yr, and switched nests between 43.3% of consecutive nesting attempts (i.e., egg-laying in discrete breeding seasons). Protecting individual nests for 7 yr, or protecting all nests within a territory for 4 yr after the last documented use of any nest when alternative nests were considered would have protected >90% of all consecutive nesting attempts. These temporal protections are longer than individual nest protections commonly applied by land management agencies (e.g., 3 yr since last use), but shorter than those suggested by Golden Eagle data collected in southwestern Idaho in an area with more alternative nests per territory. We recommend that land managers take a territory approach to Golden Eagle nesting protection, including consideration of local alternative nest-use patterns when possible. Management decisions should be based on the last use of any nest within a territory, including all potential eagle nests within a biologically meaningful distance of one another (e.g., based on local alternative nest spacing) when nest-monitoring data are limited; longer protections should be applied when knowledge of alternative nests is likely incomplete. [ABSTRACT FROM AUTHOR]

During the first half of the 20th century a moose (Alces alces) population gradually established itself on the North Slope of Utah's Uinta Mountains from founders in the Greater Yellow-stone Ecosystem. Formal management of the species commenced with an aerial survey conducted in 1957, and the first legal hunt in 1958. From this small initial population moose have expanded into other areas of northern Utah and, augmented by transplants, the statewide population has increased to an estimated 3,200 animals as of 2009. In the northern portion of the state moose appear to prosper in riparian willow (Salix sp.) habitats as well as upland shrub-dominated and forested habitats. However, there are indications that these herds are at or approaching carrying capacity. Management programs have included regular aerial surveys, harvest regulation, transplants, and dealing with "nuisance" animals along the urban-wildland interface. Since 1958 a total of 6,119 moose (bulls and cows) have been legally harvested, averaging 288 animals annually in 2004-2008. Since 1973 a total of 345 moose have been translocated within Utah and an additional 115 animals moved to Colorado. These transplants have resulted in disparate success with starter populations generally failing to achieve viability in central and southern Utah. Poaching, predation by cougars (Puma concolor), and to a lesser extent disease have contributed to losses in southern target populations. The limited success of these efforts raises questions regarding the viability of populations in areas with high summer temperatures as well as the specter of climate variation on the persistence of southern populations, generally. Several research projects have been conducted on moose in Utah. Early studies on the Uinta North Slope focused on the nutritional quality of key browse species and the determination of carrying capacity, and subsequent investigations included the effects of experimental manipulation of bull-cow ratios on calf recruitment, and telemetry-based survival studies of transplanted herds. The future of moose in Utah is discussed in light of potential limiting factors including climate change. [ABSTRACT FROM AUTHOR]