European settlement led to extirpation of native Audubon's bighorn sheep (formerly Ovis canadensis auduboni) from North Dakota during the early 20th century. The North Dakota Game and Fish Department subsequently introduced California bighorn sheep (formerly O. c. californiana) that were indigenous to the Williams Lake region of British Columbia, Canada, and Rocky Mountain bighorn sheep (O. c. canadensis) that were indigenous to the Sun River region of Montana. Although California bighorn sheep are no longer recognized as a distinct subspecies, they are smaller and adapted to a milder climate than either the native bighorn sheep of North Dakota or introduced bighorn sheep from Montana. Because reintroductions still play a key role in the management of bighorn sheep and because local adaptation may have substantial demographic consequences, we evaluated causes of variation in recruitment of bighorn sheep reintroduced in North Dakota. During 2006–2011, Montana stock recruited 0.54 juveniles/adult female (n = 113), whereas British Columbia stock recruited 0.24 juveniles/adult female (n = 562). Our most plausible mixed‐effects logistic regression model (53% of model weight) attributed variation in recruitment to differences between source populations (odds ratio = 4.5; 90% CI = 1.5, 15.3). Greater recruitment of Montana stock (fitted mean = 0.56 juveniles/adult female; 90% CI = 0.41, 0.70) contributed to a net gain in abundance (r = 0.15), whereas abundance of British Columbia stock declined (fitted mean = 0.24 juveniles/adult female; 90% CI = 0.09, 0.41; r = − 0.04). Translocations have been the primary tool used to augment and restore populations of wild sheep but often have failed to achieve objectives. Our results show that ecotypic differences among source stocks may have long‐term implications for recruitment and demographic performance of reintroduced populations. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Selection of bighorn sheep (Ovis canadensis) for translocation historically has been motivated by preservation of subspecific purity rather than by adaptation of source stocks to similar environments. Our objective was to estimate cause-specific, annual, and age-specific mortality of introduced bighorn sheep that originated at low elevations in southern British Columbia, Canada (BC ecotype), or in the Missouri River Breaks region of central Montana, USA (MT ecotype). In North Dakota, USA, mortality was similar and typically low for adult female bighorn sheep from Montana (0.09 AE 0.029 [SE]) and British Columbia (0.08 AE 0.017) during 2000-2016. Median life expectancy was 11 years for females that reached adulthood (2 yrs old); however, mortality accelerated with age and reached 86% by age 16. Mortalities resulted primarily from low rates of predation, disease, accidents, and unknown natural causes (<0.04 [upper 90% CI]). Similar survival rates of female bighorn sheep from British Columbia and Montana, coupled with greater recruitment of bighorn sheep from Montana, resulted in a greater projected rate of increase for the MT ecotype (l ¼ 1.21) than for the BC ecotype (1.02), and a more youthful age structure. These results support translocation of bighorn sheep from areas that are environmentally similar to areas that will be stocked. Potential benefits include more rapid population growth, greater resilience to and more rapid recovery from densityindependent losses, an increased possibility that rapidly growing populations will expand into adjacent habitat, increased hunter opportunity, increased connectivity among herds, and a more complete restoration of ecosystem processes. Ó 2017 The Wildlife Society.

Long‐term effects of anthropogenic disturbance to wildlife, and whether such effects have population‐level consequences, often are difficult to determine. In 1996, a recreational hiking trail (Maah Daah Hey Trail [Trail]) was constructed by the U.S. Forest Service through 4 geographic areas, each occupied by a distinct sub‐population of bighorn sheep (Ovis canadensis), in western North Dakota, USA. From 2001 to 2012, we monitored distribution, recruitment rates, and abundance of female bighorn sheep in the sub‐populations to investigate responses to activities associated with the Trail, and whether demographic consequences occurred. Female bighorn sheep at Sully Creek were displaced from, and eventually abandoned, lambing habitat subjected to intensive recreational use that was erratic and unpredictable. Consequently, females inhabiting Sully Creek had lower fidelity to lambing areas than did other sub‐populations, all of which realized 100% fidelity. Further, females inhabiting Sully Creek achieved lower recruitment of young, exhibited a substantial downward trend in recruitment rate, and a decline in abundance of females compared with the other sub‐populations also exposed to the Trail, but where perturbation was less severe and human activities were consistent, predictable, and spatial separation existed between recreationists and lambing habitat. Metapopulations of bighorn sheep occurring in fragmented habitat having minimal vertical relief may be especially susceptible to sources of disturbance, which should be a consideration when recreational facilities are developed. © 2014 The Wildlife Society.

Estimates of body condition or body composition are useful metrics, and consistency among results determined by independent investigators enhances their utility. If concordant, albeit subjective, assessments of body condition can be achieved by personnel possessing differing levels of expertise, there are important implications for generating useful information that otherwise may not be obtained by investigators facing logistic or economic constraints, or difficult field conditions. We used a serendipitous opportunity to explore level of agreement among personnel with disparate levels of anatomical knowledge and familiarity with palpation to index body condition of 55 bighorn sheep (Ovis canadensis). Our preliminary results—albeit affected by sample size—suggested the investigators interpreted and applied scoring criteria similarly, despite their differing backgrounds. Given the potential to gain meaningful information on body condition that otherwise may not be attainable, we encourage further evaluation of concordance among independent investigators whenever body condition of bighorn sheep can be rated independently by >1 individual and, further, that the information be shared widely.