Oregon’s 137 records for the southern red-backed vole come overwhelmingly from the dry side of the state. Umatilla County leads with 55, Wallowa follows with 32, and Grant and Wheeler add 25 and 13, all in the Blue Mountains country of the northeast. The Umatilla National Forest (18 records) and the Eagle Cap Wilderness (16) are the busiest named sites. The famously wet Coast Range and Willamette Valley, by contrast, show a bare handful: Lincoln and Tillamook counties with 1 each.
Not just a wet-side animal
That east-heavy map runs against expectation for a vole of cool, mossy forest floor, and it’s the most useful thing the Oregon records say. The Blue Mountains hold deep conifer shade and running water at elevation, and this species uses them readily. How much of the coastal silence is real and how much is simply less trapping effort is exactly what occurrence counts can’t answer; they record where people looked, not where the vole is thickest.
An autumn crest, and a steady grade
Reports peak in October with 35 records, on the heels of a strong June and July at 25 and 30. Spring and fall are the classic small-mammal trapping windows, and the calendar reflects them. NatureServe ranks the species S4 in Oregon, apparently secure, and it holds no separate state listing, a settled standing for a forest vole with confirmed ground from the Wallowas to the Ochocos.
Full species profile
