Oregon’s grasshopper mouse belongs to the dry side. Nearly all mapped reports come from east of the Cascades, led by Harney, Malheur, and Morrow counties in the high desert and along the Columbia Plateau. That’s sagebrush and rimrock country, the open arid ground this predatory mouse prefers, and it matches the habitat around Malheur National Wildlife Refuge and the John Day fossil beds. A single report from the Siuslaw National Forest on the coast looks like an outlier, not a pattern.
The yearly curve is sharp. Records build through spring and crest hard in July, a month that accounts for nearly half the annual total. Some of that is biology, because the mice breed and hunt most actively on warm nights, and some is effort, because summer is when biologists and road cruisers work the desert. Records measure looking as well as living.
NatureServe considers the species apparently secure in Oregon, ranked S4, and the broad east-side spread of reports fits a mouse living comfortably in big, intact sagebrush steppe.
Full species profile
