Loss of migration patterns and access to seasonal ranges are threats facing ungulate populations throughout the world. Historically, bighorn sheep in the Teton Range near Jackson Hole, Wyoming undertook an annual migration from high elevation summer range to low elevation winter range. However, the combined effects of human settlement, livestock grazing, and other factors led to the disruption and loss of migration around 50 years ago. The herd currently resides year-round at high elevation (8,000 to 12,000 feet) in Grand Teton National Park and on the Bridger-Teton and Caribou-Targhee National Forests. It is Wyoming's smallest and most isolated native herd – a remnant population of approximately 100-150 sheep. However, the population's hold on the future is tenuous owing to its small size, genetic isolation from surrounding herds, marginal winter habitat, and potential disturbance from winter backcountry recreation.
Growing recognition of the status of the herd and the need for interagency cooperation in management led to the formation of the Teton Range Bighorn Sheep Working Group in 1990 and the development of a strategic plan. The strategic plan recognized that the existing information regarding the status and threats to this herd was inadequate. Thus, the primary goal of our project is to conduct research that is closely aligned with the knowledge gaps and management needs outlined in the strategic plan.
The specific objectives are to 1) evaluate the summer and winter habitat selection strategies of the herd, 2) assess whether and how bighorn sheep avoid winter habitats due to backcountry recreation, 3) evaluate bighorn sheep use of retired domestic sheep allotments, 4) determine lamb survival through summer for a sample of bighorn ewes, and 5) evaluate summer diet selection and time-budgets. Results from this study will inform future management decisions regarding refinement or addition of seasonal closures, habitat enhancements, justification for or against a future transplant, and expansion of human development. We also hope to shed light on how these bighorn sheep have adapted behaviorally to wintering on high elevation range, as such information would better our understanding of how loss of migration influences ungulate populations.