Mule deer (Odocoileus hemionus hemionus) populations have experienced widespread declines in much of western North America and alteration or loss of habitat could be contributing to these declines. Consequently, understanding habitat features that are important to mule deer is necessary for effective management of the species and their habitat. From 2005–2012 we radio‐marked 452 mule deer with global positioning system collars across 9 distinct winter ranges to evaluate winter habitat use along the east slope of the Cascade Range in south‐central Oregon, USA. Using data from 357 mule deer across 9 analysis areas, we developed regional habitat use models for mule deer on winter range at 3 spatio‐temporal scales: herd range based on 100% minimum convex polygons around deer locations, home range based on 90% kernel density estimates of deer locations, and foraging range based on locations obtained within 2 hours of sunrise or sunset within the boundaries of the home range scale. We assessed habitat use of mule deer using a generalized linear model with a negative‐binomial link function. We validated our models with locations from an independent dataset of 95 deer that wintered within 8 of our analysis areas. Model validation indicated that regional models for all spatio‐temporal scales predicted probability of use moderately to very well. At all spatio‐temporal scales, predicted use by mule deer was greater in areas with forest canopy cover. These findings call into question large‐scale removal of western juniper (Juniperus occidentalis) in Oregon and other portions of western United States to enhance habitat for sagebrush‐dependent wildlife species. Across all spatio‐temporal scales, we documented increased probability of use of areas farther from roads open to motorized vehicle use by mule deer, highlighting the importance of limiting motorized vehicle use and access on mule deer winter range. We also documented increased use of areas with lower snow depth and on moderate slopes by mule deer. Our models can be used in land management planning to spatially predict mule deer distribution and probability of use under alternative management scenarios that affect forest canopy cover or motorized vehicle use on roads while accounting for other physical features of the landscape. Additionally, our models can be used to develop juniper removal projects to mitigate effects on mule deer winter range habitat while benefiting other wildlife. © 2018 The Wildlife Society.

Understanding the relative effects of the many factors that may influence recruitment of ungulates is fundamental to managing their populations. Over the last 4 decades, average recruitment in some populations of elk (Cervus elaphus) in Oregon, USA declined from >50 to <20 juveniles per 100 females, and several competing hypotheses address these declines. We developed a priori models and constructed covariates spanning 1977–2005 from hunter‐killed elk, elk population estimates, cougar harvest, and weather statistics to evaluate abiotic, bottom‐up, and top‐down factors that may explain annual variation and long‐term trends of pregnancy, juveniles‐at‐heel in late autumn, and recruitment of juvenile elk in spring. In models of pregnancy status, August precipitation, age, and cougar index had positive effects, whereas previous year (t − 1) winter severity or winter precipitation(t−1) and elk density had negative effects. In models of juvenile‐at‐heel in late autumn, August precipitation, August precipitation(t−1), cougar index × elk density(t−1), and age had positive effects, whereas cougar index, elk density(t−1), and winter precipitation(t−1) had negative effects. Juvenile recruitment was best explained by positive effects of August precipitation(t−1), lactation rate, and cougar index × elk density(t−1) and negative effects of cougar index and elk density(t−1). Winter severity, precipitation, and temperature were not significant in explaining variation in elk recruitment. Annual variation in pregnancy, juvenile‐at‐heel, and recruitment was most influenced by August precipitation, whereas long‐term trends in recruitment were most influenced by cougar densities with relatively weak effects of elk density. These results provide insight into causes of year‐to‐year and long‐term trends of elk recruitment and provide a basis for more rigorous evaluation of factors affecting recruitment of elk. © 2012 The Wildlife Society.

Highways are hazardous to migratory ungulates world‐wide, causing direct and indirect impacts to ungulate survival. Moreover, significant financial costs are incurred in damage from wildlife–vehicle collisions and in building and maintaining wildlife passage structures. Information is needed to link ungulate movements to collision occurrence to prioritize needed construction of wildlife crossings on highways. We simultaneously documented mule deer (Odocoileus hemionus) migration corridors and mule deer–vehicle collisions (DVCs) in South‐central Oregon, USA, over 6 years (2005–2011). We calculated Brownian Bridge Movement Models for 359 migrating mule deer equipped with Global Positioning System technology. We modeled DVC counts as functions of probability of use during migration, annual average daily traffic (AADT), and habitat characteristics. Probability of use during migration was the strongest predictor of where DVCs occurred (r = 0.93). Predicted DVCs also increased with AADT but peaked at approximately 8,000 and then decreased. Where AADT was above approximately 8,000, fewer deer attempted to cross the highway and DVCs decreased because, over time, deer either abandoned the migration route or were killed trying to cross this busy highway. Our results suggest that managers should focus on migration corridors or high‐density DVC locations to identify where fencing and under/overpasses could be most effective for maintaining migratory corridors when confronting increasing traffic and development that bisect seasonal ranges of mule deer. © 2015 The Wildlife Society.

Understanding bottom‐up, top‐down, and abiotic factors along with interactions that may influence additive or compensatory effects of predation on ungulate population growth has become increasingly important as carnivore assemblages, land management policies, and climate variability change across western North America. Recruitment and population trends of elk (Cervus canadensis) have been downward in the last 4 decades across the northern Rocky Mountains and Pacific Northwest, USA. In Oregon, changes in vegetation composition and land use practices occurred, cougar (Puma concolor) populations recovered from near‐extirpation, and black bear (Ursus americanus) populations increased. Our goal was to provide managers with insight into the influence of annual climatic variation, and bottom‐up and top‐down factors affecting recruitment of elk in Oregon. We conducted our research in southwestern (SW; Toketee and Steamboat) and northeastern (NE; Wenaha and Sled Springs) Oregon, which had similar predator assemblages but differed in patterns of juvenile recruitment, climate, cougar densities, and vegetative characteristics. We obtained monthly temperature and precipitation measures from Parameter‐elevation Regressions on Independent Slopes Model (PRISM) and estimates of normalized difference vegetation index (NDVI) for each study area to assess effects of climate and vegetation growth on elk vital rates. To evaluate the nutritional status of elk in each study area, we captured, aged, and radio‐collared adult female elk in SW (n = 69) in 2002–2005 and NE (n = 113) in 2001–2007. We repeatedly captured these elk in autumn (n = 232) and spring (n = 404) and measured ingesta‐free body fat (IFBF), mass, and pregnancy and lactation status. We fitted pregnant elk with vaginal implant transmitters (VITs) in spring and captured their neonates in SW (n = 46) and NE (n = 100). We placed expandable radio‐collars on these plus an additional 110 neonates in SW and 360 neonates in NE captured by hand or net‐gunning via helicopter and estimated their age at capture, birth mass from mass at capture, and sex. We monitored their fates and documented causes of mortality until 1 year of age. We estimated density of cougars by population reconstruction of captured (n = 96) and unmarked cougars killed (n = 27) and of black bears from DNA analysis of hair collected from snares. We found evidence in lactating females of nutritional limitations on all 4 study areas where IFBFautumn was below 12%, a threshold above which there are few nutritional limitations (9.8% [SE = 0.64%, n = 17] at Toketee, 7.9% [SE = 0.78%, n = 17] at Steamboat, 7.3% [SE = 0.33%, n = 46] at Sled Springs, and 8.9% [SE = 0.51%, n = 23] at Wenaha). In spring, of females known to have been lactating the previous autumn, 48% (SE = 3.3%, n = 56) had IFBFspring <2%, a level indicating severe nutritional limitations, compared to 20% (SE = 1.7%, n = 91) of those not lactating the previous autumn. These low levels of IFBFspring of lactating females likely resulted from a carry...

Studies of habitat selection and use by wildlife, especially large herbivores, are foundational for understanding their ecology and management, especially if predictors of use represent habitat requirements that can be related to demography or fitness. Many ungulate species serve societal needs as game animals or subsistence foods, and also can affect native vegetation and agricultural crops because of their large body size, diet choices, and widespread distributions. Understanding nutritional resources and habitat use of large herbivores like elk (Cervus canadensis) can benefit their management across different land ownerships and management regimes. Distributions of elk in much of the western United States have shifted from public to private lands, leading to reduced hunting and viewing opportunities on the former and increased crop damage and other undesired effects on the latter. These shifts may be caused by increasing human disturbance (e.g., roads and traffic) and declines of early-seral vegetation, which provides abundant forage for elk and other wildlife on public lands. Managers can benefit from tools that predict how nutritional resources, other environmental characteristics, elk productivity and performance, and elk distributions respond to management actions. We present a large-scale effort to develop regional elk nutrition and habitat-use models for summer ranges spanning 11 million ha in western Oregon and Washington, USA (hereafter Westside). We chose summer because nutritional limitations on elk condition (e.g., body fat levels) and reproduction in this season are evident across much of the western United States. Our overarching hypothesis was that elk habitat use during summer is driven by a suite of interacting covariates related to energy balance: acquisition (e.g., nutritional resources, juxtaposition of cover and foraging areas), and loss (e.g., proximity to open roads, topography). We predicted that female elk consistently select areas of higher summer nutrition, resulting in better animal performance in more nutritionally rich landscapes. We also predicted that factors of human disturbance, vegetation, and topography would affect elk use of landscapes and available nutrition during summer, and specifically predicted that elk would avoid open roads and areas far from cover-forage edges because of their preference for foraging sites with secure patches of cover nearby. Our work had 2 primary objectives: 1) to develop and evaluate a nutrition model that estimates regional nutritional conditions for elk on summer ranges, using predictors that reflect elk nutritional ecology; and 2) to develop a summer habitat-use model that integrates Deceased. Rowland et al. Elk Nutrition and Habitat-Use Models 1the nutrition model predictions with other covariates to estimate relative probability of use by elk, accounting for ecological processes that drive use. To meet our objectives, we used 25 previously collected data sets on elk nutrition, performance, and distributions from 12 study areas. We demonstra...