Malheur County accounts for nearly fifty of Oregon’s sixty-seven canyon mouse records, one of the most lopsided county splits in the state’s mammal file. The reason is geological as much as biological. The canyon mouse lives in rock: lava flows, rimrock, talus, and boulder fields, and southeastern Oregon holds the state’s great warehouse of exactly that. Harney County, with the Steens Mountain fault block, takes most of what remains.
The calendar has an odd double shape. May and July carry the most reports, but February and March show a surprising early bump. Winter records for a rock-dwelling mouse usually mean someone moved a stone or checked a crevice and found the animal at home, since these mice don’t hibernate and stay active under snow-covered talus. The warm-season peaks are the trapping seasons, when survey crews work the desert.
The species is ranked apparently secure in Oregon, and within its niche that’s believable: rimrock isn’t going anywhere. What’s missing is resolution outside the far southeast. Crook and Lake counties contribute a handful of reports, and the canyon-and-basalt country along the Deschutes has the right bones. Until someone traps it, the mouse’s Oregon range stays a desert story with a question mark at its western edge.
Full species profile
