Oregon Mule Deer Crescent Migration Corridors

More than 87 percent of Crescent mule deer tracked for >100 days displayed clear migratory behavior, making this herd one of the more migratory herds in Oregon. Most mule deer winter close to Oregon Route 31 and the northwest border of the High Desert region in areas containing Artemisia tridentata (big sagebrush), Artemisia tridentata ssp. vaseyana (mountain big sagebrush), Artemisia arbuscula (low sagebrush), and western juniper. Other mule deer winter to the north, near Crooked River and U.S. Highway 20, in areas with additional western juniper in place of low sagebrush. Both groups migrate to summer ranges featuring big sagebrush, mountain big sagebrush, and mixed-conifer species, including Pinus contorta (lodgepole pine) and Pinus ponderosa (ponderosa pine), near the Paulina Mountains, U.S. Highway 97, and the Maury Mountains. A separate group wintering near Wagontire Mountain in patches of mixed sagebrush, western juniper, and early shrub-tree habitat migrates northeast to stands of ponderosa pine and mixed-conifer forest near Donnelly Butte in spring. Mule deer cross U.S. Highway 97, Oregon Route 31, and U.S. Highway 20 during migration, with some summer ranges spanning U.S. Highway 97. In summer, Crescent mule deer often migrate to higher elevations less affected by drought. From 2010 to 2022, ODOT recorded annual averages of 209 DVCs and 55 DVCs for 88-mi (142-km) and 73-mi (117-km) stretches of U.S. Highway 97 and Oregon Route 31, respectively (ODOT, 2023). These estimates account for multiple deer species. In 2012, ODOT constructed two wildlife undercrossings with guiding fences on U.S. Highway 97 near Lava Butte, reducing DVCs within the fenced area by 85 percent the first year after installation and 100 percent the second year (Bliss-Ketchum and Parker, 2015). Eight years later, ODOT finished two additional undercrossings near Gilchrist, Oregon, and one more near South Century Drive outside of Sunriver, Oregon in 2022. The Crescent mule deer herd inhabits sections of the Paulina and Fort Rock Wildlife Management Units (WMUs), which were included in the Oregon Department of Fish and Wildlife (ODFW) Mule Deer Initiative five-year plans in 2010 and 2015, respectively (ODFW, 2015, 2020). Since then, the ODFW, in collaboration with the Bureau of Land Management (BLM), and the Natural Resources Conservation Service (NRCS) Sage Grouse Initiative (SGI), removed 1,966 acres (796 ha) of western juniper, reseeded 525 acres (212 ha) with native shrubs and grasses, and constructed 812 water development projects along with other habitat improvement efforts. Water development projects included drilling wells, developing springs, piping water, repairing guzzlers, and managing riparian areas to help mitigate the severe to exceptional droughts that affect many Crescent mule deer on their winter ranges. These mapping layers show the location of the migration corridors for mule deer (Odocoileus hemionus) in the Crescent population in Oregon. They were developed from 212 migration sequences collected from a sample size of 95 animals comprising GPS locations collected every 3-13 hours.

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