Oregon Mule Deer Juniper-Silvies Migration Corridors

The Juniper-Silvies mule deer herd uses three main winter ranges. Many of the southern winter ranges near Oregon Route 205 have been affected by wildfire at least once in the last 40 years, resulting in a mosaic of native and nonnative grassland, sagebrush, and western juniper. In 2012, the 160,800-acre (65,073-ha) Miller Homestead fire burned the entire southern section of this winter range (BLM, 2023a). When migrating, these mule deer often travel between Mud Lake and Harney Lake, shallow alkaline lakes that dry completely during droughts. Northwestern winter ranges on the Glass Buttes and Juniper Ridge are covered by western juniper and early shrub-tree habitat, as well as a variety of sagebrush species. The habitats of winter ranges close to U.S. Highway 395, Dry Mountain, and Street Flat are similar but contain higher proportions of ponderosa pine, grassland, and mixed-conifer forest instead of early shrub-tree habitat. Including the eastern portion of these winter ranges, about 55,420 acres (22,428 ha) burned in the 2007 Egley Complex fire (BLM, 2023a). Post-fire, shrub recovery varied by elevation and aspect across the area. Juniper-Silvies mule deer collectively migrate to summer ranges near Silver Creek, King Mountain, Emigrant Creek, and Bald Butte. In comparison to winter ranges, summer ranges contain more ponderosa pine, western juniper, and mixed-conifer forest and scattered sections of mixed sagebrush.  Large portions of summer range burned during the 73,258-acre (29,646-ha) Pine Springs Basin fire in 1990 and the 55,421-acre (22,428-ha) Egley Complex and 52,890-acre (21,404-ha) Bear Canyon fires in 2007 (BLM, 2023a). Ceanothus spp. (California lilac) and regenerating conifers dominate the burned areas of this summer range. 
The Juniper-Silvies mule deer herd encounters several challenges, including nonnative annual grass invasion, western juniper encroachment, post-fire habitat succession, extreme drought, interactions with feral horses, and highway mortality. Wildfires burned more than 76,800 acres (31,000 ha) of winter range in the past 40 years, converting large areas to invasive annual grasses. Sixteen years post-fire, burned habitat on summer range has neared the end of peak productivity, and conifer succession and senescence are beginning to affect shrubs. The Palomino Butte and Warm Springs Herd Management Areas (HMAs) also overlap multiple mule deer winter ranges and contain approximately 212 and 272 feral horses, respectively, both above their respective maximum appropriate management levels (AMLs) of 64 and 202 horses (BLM, 2023b). U.S. Highway 20 also contributes to significant annual mortalities: an average 41.8 DVCs (all local deer species) were recorded each year from 2010 to 2022 for a 36-mi (58-km) section of road near Burns, Oregon (ODOT, 2023).
These mapping layers show the location of the migration corridors for mule deer (Odocoileus hemionus) in the Juniper-Silvies population in Oregon. They were developed from 48 migration sequences collected from a sample size of 17 animals comprising GPS locations collected every 5-13 hours.

Tags: animal-behavior, biota, burns, migration-organisms, migratory-species, oregon, united-states, usgs-67917772d34ea6a4002bfad2
Organization: Department of the Interior