Missouri sits near the eastern edge of the western harvest mouse’s range, and the state’s 87 records sketch where its grassland habitat survives. St. Charles and St. Louis counties lead the list, a cluster along the Missouri and Mississippi river corridors, with a second scattering through the Ozarks in Douglas, Ozark, and Newton counties. Refuges like Mingo and Swan Lake, along with the tall grass at Big Oak Tree State Park, are the kinds of open, weedy ground it uses.
Reports run heaviest from November through January, with another rise in March. That cool-season bulge likely reflects trapping schedules in managed grasslands more than anything the mice are doing; harvest mice stay active all winter beneath the surface litter.
NatureServe considers the species apparently secure in Missouri, an S4 rank. The spread across seventeen counties supports that: this isn’t a one-site story but a thin, wide presence wherever rank grass and marsh edges persist.
Full species profile
