Louisiana’s eastern harvest mouse record runs against the usual script. Reports don’t peak in summer; they pile up in February, with a second rise in December. For a mouse that’s active year-round, a winter-heavy calendar points straight at the observers: cool-season trapping surveys, when the grass lies flat and other fieldwork brings biologists out.
The 89 records spread across 11 parishes in a loose diagonal, from Caddo in the northwest through East Baton Rouge to Washington Parish on the Mississippi line. That’s a wide net for a mouse most people never see. Eastern harvest mice live in dense grass, weaving ball nests above the ground, and they turn up in a survey trap far more often than in front of someone’s eyes.
NatureServe hasn’t been able to rank the species in Louisiana, grading it Unrankable, which usually means too little information rather than any clear trend. The records so far suggest a mouse more widespread in the state than the gaps imply, but records measure where people looked. Filling in the parishes between the dots is exactly the work that would turn unrankable into a real answer.
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