Abnormal Coloration in Bighorn Sheep (Ovis canadensis)

Despite no mention of abnormal coloration in bighorn sheep (Ovis canadensis) in two earlier reviews addressing that subject, leucism, piebaldism, and melanism do occur in that species. Presented herein is a compilation of observations of abnormally colored bighorn sheep (Ovis canadensis) assembled with information obtained from personal observations and the use of on-line literature search services, other on-line searches, private interviews, and a questionnaire. The majority of abnormally colored bighorn sheep have been described as white or albinistic . Review of images provided by respondents, however, verified that the majority of such reports were of leucistic individuals. White or leucistic bighorn sheep have been described from 23 specific geographic areas distributed among one Canadian province, one state in Mexico, and seven of the western United States; reports of piebaldism or of melanism are much less frequent

Feral Horses, Feral Asses, and Professional Politicians: Broodings From a Beleaguered Biologist

As a member of National Wild Horse and Burro Advisory Board, I gained insight into several aspects of feral equid management that previously had been somewhat cryptic. Foremost in my experience, though, was the dedication and professionalism of the board members with whom I served. During my tenure, the professional approach to management and the frustration faced by employees within the Horse and Burro Program became increasingly apparent. Further came the realization that the effectiveness of the board and program can be improved substantially, if (1) the board is provided the opportunity to rebut or counter incorrect or misleading information received during public testimony, and those statements are shared with elected officials; (2) any member of the Board whose term expires can remain involved in board activities until that board member is reappointed or replaced; and (3) congressional representatives place the well-being of public rangelands ahead of personal ambitions and political expediency. In the absence of corrective actions, the public rangelands will continue to deteriorate, and the concomitant impacts to native species and feral equids will remain unabated, if not exacerbated

Variation in diet of desert bighorn sheep (Ovis canadensis nelsoni): Tradeoffs associated with parturition

Selection of forage and habitats is driven by nutritional needs of individuals. Some species may sacrifice nutritional quality of forage for the mother in favor of safety of offspring (risk-averse strategy), immediately following parturition. We studied diet quality and forage selection by bighorn sheep before and following parturition to determine how nutritional demands associated with rearing offspring influenced forage acquisition. We used desert bighorn sheep, Ovis canadensis nelsoni, to investigate that potential tradeoff. We captured and radio-collared female bighorn sheep from 2016 to 2018. We used vaginal implant transmitters (VIT)s in pregnant females to identify parturition and to capture and radio-collar neonates to monitor survival of young. We collected fecal samples throughout the breeding season and throughout the year to understand diet quality and composition throughout those temporal periods. We determined diet quality and composition for pre-parturient females, females provisioning offspring, females that lost offspring, and non-pregnant individuals using fecal nitrogen and DNA metabarcoding analyses. Additionally, we compared the diet quality and composition of offspring and adult females during the spring, as well as summer and winter months. Our results indicated differences in diet quality between individuals provisioning offspring and those whose offspring had died. Females that were provisioning dependent young had lower quality diets than those that lost their offspring. Diet composition among those groups was also markedly different; females that had lost an offspring had a more diverse diet than did females with dependent young. Diet quality differed among seasons, wherein offspring and adult females had higher quality diets during the spring months, with decreasing quality as the year progressed. Diet diversity was similar across seasons, although spring months tended to be most diverse. Our results support tradeoffs associated with risk-averse strategies made by adult females associated with parturition. Nutritional quality of forage was linked to provisioning status, indicating that females were trading diet quality for safety of offspring, but those females whose offspring had died selected high quality forages. Those results help explain habitat selection observed in mountain ungulates around parturition and provide further insight into the evolutionary processes and adaptive significance exhibited by those specialized artiodactyls

Hunting and mountain sheep: Do current harvest practices affect horn growth?

The influence of human harvest on evolution of secondary sexual characteristics has implications for sustainable management of wildlife populations. The phenotypic consequences of selectively removing males with large horns or antlers from ungulate populations have been a topic of heightened concern in recent years. Harvest can affect size of horn-like structures in two ways: (a) shifting age structure toward younger age classes, which can reduce the mean size of horn-like structures, or (b) selecting against genes that produce large, fast-growing males. We evaluated effects of age, climatic and forage conditions, and metrics of harvest on horn size and growth of mountain sheep (Ovis canadensis ssp.) in 72 hunt areas across North America from 1981 to 2016. In 50% of hunt areas, changes in mean horn size during the study period were related to changes in age structure of harvested sheep. Environmental conditions explained directional changes in horn growth in 28% of hunt areas, 7% of which did not exhibit change before accounting for effects of the environment. After accounting for age and environment, horn size of mountain sheep was stable or increasing in the majority (similar to 78%) of hunt areas. Age-specific horn size declined in 44% of hunt areas where harvest was regulated solely by morphological criteria, which supports the notion that harvest practices that are simultaneously selective and intensive might lead to changes in horn growth. Nevertheless, phenotypic consequences are not a foregone conclusion in the face of selective harvest; over half of the hunt areas with highly selective and intensive harvest did not exhibit age-specific declines in horn size. Our results demonstrate that while harvest regimes are an important consideration, horn growth of harvested male mountain sheep has remained largely stable, indicating that changes in horn growth patterns are an unlikely consequence of harvest across most of North America.Utah Division of Wildlife Resources; National Wild Sheep Foundation (WSF); Wyoming Wild Sheep Foundation; Alberta Wild Sheep Foundation; California Wild Sheep Foundation; Arizona Desert Bighorn Sheep Society; Wyoming Governor's Big Game License Coalition; Iowa Foundation for North American Wild Sheep; Utah Foundation for North American Wild Sheep; Pope and Young ClubOpen access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Indexing body condition of bighorn sheep: potential for concordance among independent investigators?

Abstract 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

The Bighorn Habitat Assessment Tool: A Method to Quantify Conservation Value on Landscapes Impacted by Mining

We present a methodology to assess the conservation value of mitigation lands for desert bighorn sheep (Ovis canadensis nelsoni) within landscapes impacted by historic and ongoing industrial uses. The Bighorn Habitat Assessment Tool (BHAT) was developed to support the adaptive management of the Cushenbury population of bighorn sheep located on the north slope of the San Bernardino Mountains in southern California, USA. We use a novel formulation of conservation value integrating the results of resource selection function analysis and reclamation credits, reflecting the degree to which degraded habitat is enhanced to benefit wild sheep. Our method seeks to balance conservation objectives simultaneously with the economic development of a working mine landscape. Specifically, the BHAT can be used to (a) establish a habitat reserve providing maximum benefit to the unique requirements of bighorn sheep; (b) incentivize voluntary action by industry to ensure mining activities are compatible with conservation; (c) allow for the evaluation of multiple mine planning and resource management alternatives; and (d) ensure that future compensatory mitigation actions for mining activity are grounded in the best available science. Our methodology is transferrable to the management of other wild sheep populations occupying mine-influenced landscapes for which sufficient data are available to complete resource selection analyses