Western harvest mice are tiny, secretive rodents that build grass nests low in dense vegetation, and that lifestyle explains why every one of Montana’s 72 records comes from GBIF trapping data rather than an iNaturalist photo. It’s simply not an animal people run into by chance.
The monthly counts jump around in an odd way: 15 records in March, none in April or May, then a scattered run through summer that peaks at 19 in September. That kind of on-off pattern usually points to when small-mammal trapping surveys happened to run rather than any real seasonal shift in the mouse’s own activity. Red Rock Lakes National Wildlife Refuge, Flathead Lake, and the Missouri River corridor all offer the grassy, wetland-edge cover this species favors. NatureServe ranks it S5, secure, in Montana, so the modest record count reflects how hard the species is to detect, not any real concern about its numbers.
Full species profile
