Cooperative Fish and Wildlife Research Units Program: Wyoming
Education, Research and Technical Assistance for Managing Our Natural Resources

Although migration is the most profitable foraging strategy in numerous systems, many migratory populations contain individuals that do not migrate – a phenomenon known as partial migration. Three different migratory strategies have been observed in a mule deer herd wintering in Wyoming's Red Desert. These include long-distance migrants that travel 150 miles to the Hoback Basin for the summer (the longest recorded mule deer migration, named the Red Desert to Hoback migration), medium-distance migrants that migrate nearly 70 miles to the southern Wind River Range for the summer, and short-distance migrants that either migrate less than 30 miles north for the summer or live year-round in the Red Desert. Although these different types of migration have been observed for several years, little is known about the costs or benefits associated with each migratory strategy and how varying environmental conditions (i.e., annual precipitation, mean temperature) or landscape changes (i.e., fire, fencing) may affect each strategy or how a diversity of migratory tactics benefits the productivity of the overall herd. The primary objective of our research is to compare the costs and benefits of each migratory strategy (long, medium, short-distance migration). This study is being conducted as a collaborative project among the Wyoming Unit, the Wyoming Game and Fish Department and Bureau of Land Management. Evaluating different migratory tactics in the Sublette Mule Deer Herd is an important step in understanding factors maintaining variability in migration behavior and will aid in future conservation and management efforts.