Deer mice are one of Massachusetts’ most-recorded rodents on paper, but only 8 of the state’s 1,031 records come from iNaturalist photos; nearly all the rest trace back to GBIF’s trapping and specimen data. That split makes sense for a small, strictly nocturnal mouse that spends its life under leaf litter and brush, rarely crossing paths with a camera. Nearly all of the records, 970, come from Worcester County, with Franklin County a distant second at 54.
Records climb through summer to a sharp August peak, more than a hundred times the near-zero winter months, a pattern that tracks field survey season far more than the mouse’s own activity, since deer mice are active year-round under snow and leaf cover alike.
Full species profile
