Ranges and forays of Bighorn Sheep (Ovis Canadensis) in the Thompson region of British Columbia

The movements of animals provide insight into their spatial distribution, landscape use, gene flow, and potential for diseases transmission, and thus are an important measure in the study of the species’ ecology and the development of conservation plans and management practices. Species exhibiting gregarious social-structures generally conduct their movements as part of a herd, but also as individual, and so can increase their likelihood of contact with other herds or species, including domestic individuals. This study provides an analysis of movements of Bighorn Sheep (Ovis canadensis) in the Thompson Region of British Columbia relative to proximity of domestic sheep (Ovis aries). I used GPS location data of 40 rams from four different herds monitored during 2015-2018 toevaluate home range and core areas of each ram group while providing the comparison of four home range estimation methods. Each of the bands exhibited non-migratory behaviour. The animals used the same geographic area through the year, rather than migrating across the landscape. Further, while their seasonal ranges overlapped significantly, the ranges were considerably larger during the relatively short rutting season than in other seasons. These observations match those reported in previous studies where reintroduced Bighorn Sheep herds occupied relatively small areas and often exhibited no or short migration movements. The results of this study confirm connectivity between my focal herds and an area occupied by a herd not included in this study. Collared rams from the focal herds displayed short foray movement of less than 6 km, which contrasts with that reported elsewhere. These short forays suggest a lower level of risk of contact with domestic animals existing outside of the herd home ranges. However, it should be emphasized that despite this lower risk, the likelihood of a transmission event cannot be completely discounted. Also, significant amount of private land overlaps or lays adjacent to the home ranges of the study herds, indicating that expanded future use of these lands for livestock range and/or an increase in Bighorn Sheep populations will increase the likelihood of contact between domestic and wild sheep. Thus the risk of contact with domestic sheep is high. Overall, my findings are relevant for establishing operational rules for land use practices and activities seeking to reduce impacts on bighorn herds.