Wisconsin Norway Rat records along the Lake Michigan shore and near Horicon or Kettle Moraine should be read through nearby ports, towns, farms, campgrounds, and waste infrastructure, not as a preference for natural shoreline or refuge habitat. Small peaks in March and July–August may reflect building encounters, control activity, and observer opportunity rather than a biological statewide cycle.
The 42 iNaturalist reports are submissions, not a measure of Norway Rat abundance. People rarely document this widespread commensal unless it is unusually visible, and repeated records around accessible urban sites can dominate a map that substantially underrecords farms and buildings.
Full species profile
