Grand Teton National Park biologists have detailed a new long-distance mule deer migration route that spans two states and traverses the Teton Range. The route was the latest of four long-distance migrations that park biologists have documented since 2013 in an effort to better understand mule deer, the routes they use to access winter ranges, and conservation risks along those routes.
Park biologists captured a female mule deer near Colter Bay last fall and fitted her with a GPS radio collar. Beginning in early November, the deer made her way around the north end of Jackson Lake and then west over the Tetons to winter range along the Teton River in Idaho. Her route crossed the Snake River near Steamboat Mountain then climbed the east flank of the northern Teton Range. She passed to the north of Mount Berry at an elevation of 8,900 feet and crossed the Teton crest near "Peak 8,456" before descending the west slope of the range. The data revealed that she traveled roughly 45 miles and more than 2,000 vertical feet over 4 days to get to winter range.
Prior to the study, park biologists were aware that deer wintering in at least three different areas in eastern Idaho make long-distance migrations to the Tetons thanks to research conducted by the Idaho Fish and Game Department. However, the exact migration routes those deer use were unknown. This study provided detailed information on one of those routes, which crosses multiple jurisdictions, for the first time.
Biologists were able to glean the data for this study quickly thanks to GPS radio collars which upload data via satellite uplink. The collars have revealed important wildlife connections between the park and public and private lands outside of park boundaries.
Earlier work in this study documented mule deer migrations from Grand Teton to three other distant wintering areas. The three migration routes used to access winter ranges on the east side of the Continental Divide include one through southeastern Yellowstone National Park to the North Fork of the Shoshone River, another through high mountain passes in the Teton and Washakie Wilderness areas and across the Absaroka Divide to the South Fork of the Shoshone River, and a third along the Gros Ventre River drainage and across the continental divide to winter ranges near Dubois.
Funding for this project was provided by the Grand Teton National Park Foundation, including a leadership grant from the Knobloch Family Foundation in 2015. This ongoing study is part of a long-term migration initiative started by the park in the 1990s. Other migrations studied include those of bison, elk, pronghorn, red-tailed hawks, osprey, and rough-legged hawks. Collaborators in this work include the Wildlife Conservation Society, Craighead Beringia South, Teton Raptor Center, National Elk Refuge, and Wyoming Game and Fish Department.