All of Wyoming’s mapped plains harvest mouse reports come from the state’s eastern tier: Goshen, Weston, and Campbell counties, with a few more scattered along the Nebraska and South Dakota lines. That’s the low, warm, grassy side of Wyoming, and the rest of the state may simply be too high and cold for a mouse of the central plains. Or the east is just where the traps have been. With twelve total reports, both can be true at once.
The dates spread from spring through fall, with small bumps in May, June, and September. Nothing in a sample this size supports firm conclusions, but the absence of winter reports fits a small mouse that stays deep in grass and nest when the plains freeze.
NatureServe considers the mouse apparently secure in Wyoming, ranked S4, and the IUCN lists it as Least Concern. Thunder Basin’s big grasslands and the stream corridors along the state line hold its kind of habitat in broad blocks. The record is sparse, but nothing in it suggests trouble; it mostly suggests that few people have gone looking for a mouse this small.
Full species profile
