Iowa’s grasshopper mouse reports hug the state’s western edge. Fremont and Monona counties, both in the Loess Hills above the Missouri River, supply the bulk of the records, with a second pocket in Dickinson County’s prairie-lake country to the north. The named sites tell the same story: the Riverton Wildlife Management Area and Cayler Prairie State Preserve, two of the state’s best remaining pieces of native grassland, account for a large share of the total. For a stout little predator that hunts grasshoppers, beetles, and even other mice across open dry ground, that’s exactly the right country.
Records peak in July and August, then flare again in October. That second bump likely tracks fall trapping effort as much as mouse activity, since counts of reports reflect where and when people looked. The most recent Iowa record dates to late October 2023, so the file is at least current.
NatureServe ranks the mouse S3, vulnerable in Iowa, though it remains secure globally. A grassland hunter in tallgrass country is only as secure as the prairie beneath it, and most of Iowa’s native sod was plowed generations ago.
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