Migration Routes of Mule Deer in the Red Desert Population in Wyoming

Mule deer within the Red Desert population, part of the larger Sublette herd, make the longest ungulate migration ever recorded in the lower 48 states (fig. 33). Here, mule deer travel an average one-way distance of 150 mi (241 km) from the Red Desert in the south to the Gros Ventre Range and Teton Range in the north. This migration originates in the desert sagebrush basins of the Red Desert area of southwest Wyoming where deer winter. In spring, an estimated 500 deer travel 50 mi (84 km) north across the desert to the west side of the Wind River Range. From there they merge with 4,000 to 5,000 other deer that winter in the foothills of the Wind River Range and then travel a narrow corridor along the base of the Wind River Range for 60 mi (97 km) before crossing the upper Green River Basin. Deer must navigate several bottlenecks, one as narrow as 50 m (164 ft) wide, at the outlets of Fremont, Willow, and Boulder Lakes. In the final leg of the journey, they travel another 30–50 mi (48–80 km) to individual summer ranges in the Gros Ventre Range. These data provide the location of migration routes for mule deer (Odocoileus hemionus) in the Red Desert herd in Wyoming. They were developed from Brownian bridge movement models using 392 migration sequences collected from a sample size of 148 animals comprising GPS locations collected every 2-8 hours.