Western harvest mice build small, round nests of woven grass low in dense vegetation, a habit that ties them to the grassy edges and wetland margins around Malheur National Wildlife Refuge rather than the open sagebrush flats nearby. At barely a few grams, they’re among the smallest rodents likely to turn up in a trap in Oregon’s high desert.
Most of the state’s 140 records come from GBIF specimen data rather than photographs, just 3 from iNaturalist, a fair reflection of how easily a mouse this small and secretive goes unnoticed. Records cluster in March, June, and July, too few to describe a strong seasonal signal. NatureServe ranks the species S4, apparently secure, in Oregon.
Full species profile
