Oregon Mule Deer Warner Winter Ranges

The Warner mule deer herd uses varying life history strategies corresponding with multiple migratory and nonmigratory tactics. Mule deer wintering near Warner Valley and Oregon Route 140 migrate west in spring to Bald Hills and higher elevations in the Warner Mountains, and nonmigratory deer reside along U.S. Highway 395. One GPS-collared mule deer migrated south from a winter range in Oregon to a summer range northwest of Mosquito Valley in northern Nevada. Habitats in this area vary widely. Winter and annual ranges largely consist of mountain big sagebrush, antelope bitterbrush, A. tridentata wyomingensis (Wyoming sagebrush), low sagebrush, western juniper, and early shrub-tree habitats with patches of nonnative annual grasses. Summer ranges contain mixed-conifer forest or high desert sage-steppe habitats usually including western juniper, ponderosa pine, and quaking aspen with open sections of mixed sagebrush, wetlands, and early shrub-tree habitat. An individual mule deer wintering near Crump Lake in low sagebrush and Wyoming sagebrush-dominated habitats migrated north to a summer range on Hart Mountain characterized by mountain big sagebrush, antelope bitterbrush, and quaking aspen. Other mule deer winter to the north, near Lake Abert, where low sagebrush and Wyoming sagebrush compete with nonnative grasses. These mule deer migrate south to the Warner Mountains in spring, overlapping other Warner mule deer on their summer ranges. One mule deer migrated almost 54 mi (86 km)—the longest migration within the herd— along the ridge of the Warner Mountains, passing through these summer ranges to reach Turpin Ridge. The Warner mule deer herd faces several threats, including annual grass invasion and western juniper encroachment, as well as changing climate regimes that reduce forage quality and water availability. Predation, diseases such as epizootic hemorrhagic disease, and highways also contribute to mortality. Each year from 2010 to 2022, ODOT recorded on average 78.7 DVCs for a 30-mi (49-km) stretch of U.S. Highway 395, and an additional 10.7 DVCs for a 32-mi (51-km) section of Oregon Route 140 (ODOT, 2023). In 2010, the Mule Deer Initiative included the Warner WMU and since then, ODFW, BLM, and NRCS SGI have removed 49,940 acres (20,210 ha) of western juniper, treated 13,568 acres (5,491 ha) to eliminate invasive plants, and conducted prescribed burns on 13,002 acres (5,262 ha), along with other habitat improvement efforts (ODFW, 2015, 2020). The organizations also improved 7,018 acres (2,840 ha) of aspen stands by removing conifers, constructing fences to prevent livestock grazing, and using controlled burns to remove conifer slash. These mapping layers show the location of the winter ranges for mule deer (Odocoileus hemionus) in the Warner population in Oregon. They were developed from 85 winter sequences collected from a sample size of 32 animals comprising GPS locations collected every 5-13 hours.

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  "geospatial"
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