Timing of births in ungulates is influenced by ecological factors, and differences in seasonality of births have evolutionary implications for these mammals. Birthing habitat is one of the most important home-range attributes for ungulates, and disturbances during this time can decrease survival of young and population growth. We calculated timing of births and quantified habitat selected by nursery groups (i.e., females with young) of desert bighorn sheep (Ovis canadensis nelsoni) to produce and project a geographic information system (GIS) model of lambing period habitat (i.e., birthing locations and areas used up to 6 weeks post-parturition) in southeastern Utah, United States. We then applied that model to identify suitable lambing period habitat in an adjacent area for a population of Rocky Mountain bighorn sheep (O. c. canadensis). We monitored 19 global positioning system (GPS) collared females from 2012 to 2013 to delineate the birthing season. We used GPS locations during that time and logistic regression within a model-selection framework to differentiate between lambing period habitat and random locations based on habitat and anthropogenic covariates. We used model coefficients to produce and project a GIS model of lambing period habitat. Across both years, 89% of 45 births occurred in May (range = April 27–June 9). We quantified covariate values at 750 lambing period and 750 random locations during that time in the San Rafael study area. The top model included elevation, slope, terrain ruggedness, aspect, existing vegetation type, and distance to trails and roads. Those variables predicted lambing period habitat for desert bighorn sheep (rho = 0.99, P = 0.02). We then overlaid that model on 1,130 GPS locations from 17 female Rocky Mountain bighorns in the Green River study area. In both areas, a mean of 71% of locations were in the top two (of five) probability categories (San Rafael high = 37%, medium high = 31%; Green River high = 50%, medium high = 23%). Females in lambing period habitat preferred steep, north-facing slopes, rugged terrain, low elevation, and avoided roads. Our GIS model projected areas of lambing period habitat for adjacent desert and Rocky Mountain bighorns and provided land managers with a map of habitat in areas where resource extraction and recreation are increasing. Identifying timing of parturition, and high-probability lambing period habitat, will help managers mitigate temporal and spatial conflicts between bighorn sheep and anthropogenic activities. Similar data regarding timing of births and a GIS model can be applied to conserve habitat for other ungulates also.

Monitoring dispersal, habitat use, and social mixing of released ungulates is crucial for successful translocation and species conservation. We monitored 127 female bighorn sheep (Ovis canadensis) released in three populations from 2000 to 2009 to investigate if augmented bighorns expanded and shifted seasonal ranges, used different habitat compared with resident females, and if animals mixed socially. Augmented bighorns in all populations expanded range use compared with residents by shifting utilization distributions. Size of utilization distributions, however, were smaller for augmented females compared with residents in all areas except one. Overlap of seasonal utilization distributions between augmented and resident bighorns and use of slope and elevation differed across populations. In two populations, differences in size and overlap of seasonal utilization distributions and use of slope and elevation supported the hypothesis that habitat use of bighorns in their source area influenced their habitat use after release. Mixing between resident and augmented adult females occurred on average during only 21% of sightings and was similar across populations. Our results clarify how augmented bighorns mix with resident animals and how habitat use is modified following augmentations. Such information is needed to improve bighorn sheep augmentations and can be applied to augmentations of other ungulates.

ABSTRACT Infectious disease contributed to historical declines and extirpations of bighorn sheep ( Ovis canadensis ) in North America and continues to impede population restoration and management. Reports of pneumonia outbreaks in free‐ranging bighorn sheep following contact with domestic sheep have been validated by the results of 13 captive commingling experiments. However, ecological and etiological complexities still hinder our understanding and control of respiratory disease in wild sheep. In this paper, we review the literature and summarize recent data to present an overview of the biology and management of pneumonia in bighorn sheep. Many factors contribute to this population‐limiting disease, but a bacterium ( Mycoplasma ovipneumoniae ) host‐specific to Caprinae and commonly carried by healthy domestic sheep and goats, appears to be a primary agent necessary for initiating epizootics. All‐age epizootics are usually associated with significant population declines, but mortality rates vary widely and factors influencing disease severity are not well understood. Once introduced, M. ovipneumoniae can persist in bighorn sheep populations for decades. Carrier females may transmit the pathogen to their susceptible lambs, triggering fatal pneumonia outbreaks in nursery groups, which limit recruitment and slow or prevent population recovery. The demographic costs of disease persistence can be equal to or greater than the impacts of the initial epizootic. Strain typing suggests that spillover of M. ovipneumoniae into bighorn sheep populations from domestic small ruminants is ongoing and that consequences of spillover are amplified by movements of infected bighorn sheep across populations. Therefore, current disease management strategies focus on reducing risk of spillover from reservoir populations of domestic sheep and goats and on limiting transmission among bighorn sheep. A variety of techniques are employed to prevent contacts that could lead to transmission, including limiting the numbers and distribution of both wild and domestic species. No vaccine or antibiotic treatment has controlled infection in domestic or wild sheep and to date, management actions have been unsuccessful at reducing morbidity, mortality, or disease spread once a bighorn sheep population has been exposed. More effective strategies are needed to prevent pathogen introduction, induce disease fadeout in persistently infected populations, and promote population resilience across the diverse landscapes bighorn sheep inhabit. A comprehensive examination of disease dynamics across populations could help elucidate how disease sometimes fades out naturally and whether population resilience can be increased in the face of infection. Cross‐jurisdictional adaptive management experiments and transdisciplinary collaboration, including partnerships with members of the domestic sheep and goat community, are needed to speed progress toward sustainable solutions to protect and restore bighorn sheep populations. © 2017 The Wildlife Society.

Female polar bears construct maternal dens in snowdrifts in autumn. Forward-looking infrared (FUR) has been used to locate dens to prevent disruption of denning by human activities, but the results have been mixed. To identify limitations and optimal conditions for locating dens, we took handheld FUR images of three artificial dens under varied conditions. We tested variables hypothesized to influence detectability with linear models using the zero-inflated negative binomial distribution. Solar radiation, wind speed, and den wall thickness reduced the likelihood of detecting dens. The negative effect of wind speed on detectability increased with increasing distance. To maximize the efficacy of ground-based FUR, den surveys should be conducted when solar radiation is less than 16 watts per square meter (night) and when wind speed is less than 10 kilometers per hour. Adherence to these guidelines will maximize the protection that FUR can afford to denning bears.

Post-Den Emergence Behavior and Den Detection of Polar Bears (Ursus maritimus) in Northern Alaska and the Southern Beaufort Sea Rusty W. Robinson Department of Plant and Wildlife Sciences, BYU Master of Science Pregnant polar bears (Ursus maritimus) construct maternal dens out of snow in the autumn where they give birth to and raise altricial young. In recent years, there has been a decrease in polar sea ice extent and thickness, which has led to changes in denning behavior. One such change in the southern Beaufort Sea (SBS) is that polar bears are selecting maternal den sites on land, rather than on unstable sea ice. This change, coupled with expanding petroleum exploration along Alaska’s North Slope, heightens the likelihood of bear-human interactions at maternal den sites. The purpose of this research was to 1) describe polar bears’ post-den emergence behavior, establishing a benchmark for comparison to identify behavioral changes associated with climate change and disturbance, and 2) explore factors influencing the efficacy of a currently used den detection method, forward-looking infrared (FLIR). Maternal den sites were observed along Alaska’s North Slope from March to April of 2009 and 2010. The mean length of stay at den sites post-emergence was 11.3 ± 7.5 d. The mean date of den emergence was 14 March; abandonment 26 March. Adult females were generally inactive (58.4% out-of-den time) with standing being the most prevalent activity (49.9%). Cubs were generally active (76.7%), playing more than any other activity (45.3%). Bears spent the majority of their time in the den (97.3% for adult females and 99% for cubs) with short bouts of intermittent activity (x! = 7 min 42 s). We documented the death of one member of a triplet polar bear litter at its den site. All three cubs showed low activity levels relative to other cubs observed, and one died within one week of den emergence. Necropsy confirmed that the dead cub had a low body weight and was malnourished. Capture later confirmed that the two surviving cubs were also undersized. Triplet litters are often smaller and suffer higher mortality rates than singletons and twins. This cub was not only a triplet but also born following 2 y of record minimum sea ice extent, both of which may have played a role in this cub’s death. Concurrent with the den emergence portion of this work, we conducted a separate study to identify limitations and optimal conditions for locating dens using FLIR. We took handheld FLIR images of three artificial dens under varied conditions. We tested variables hypothesized to influence detectability with linear models using a zero-inflated negative binomial distribution. Solar radiation, wind speed, and den wall thickness reduced the likelihood of detecting dens. The negative effect of wind speed on detectability increased with increasing distance. To maximize the efficacy of hand-held FLIR, den surveys should be conducted when solar radiation is <16 w/m (night) and when wind speed is <10 km/h (6 mph). Adherence to these guidelines will maximize the protection FLIR can afford to denning bears.

In March 2009, we documented the death of one member of a triplet polar bear (Ursus maritimus) litter at its den site in the southern Beaufort Sea (SBS) of Alaska. We used a self-contained video camera unit to document activity between den emergence and departure. All three cubs showed low activity levels relative to other cubs observed, and one died within one week of den emergence. Necropsy confirmed that the dead cub had a low body weight and was malnourished. Capture later confirmed that the two surviving cubs were also undersized. Polar bear cub survival is influenced by many factors including litter size and sea ice conditions. Triplet litters are often smaller and suffer higher mortality rates than singletons and twins. This cub was not only a triplet but also born following 2 years of record minimum sea ice extent, both of which may have played a role in this cub's demise.