Illinois has 180 records of the western little brown myotis, more than most bats covered here but still only enough for the rare bucket, since small-mammal reporting across the state stays thin overall. Sightings concentrate around Cache River State Natural Area, Chautauqua National Wildlife Refuge, and the Upper Mississippi River refuge lands, the wetland corridors this bat relies on for hunting low over slow water.
May, June, and July are tied for the most records in Illinois, an even split that fades quickly once fall arrives. That pattern reflects how often people go looking and how easy the bats are to detect, not a summer boom in the population. The more striking number is the conservation rank itself: NatureServe still lists the species S5, Secure, in Illinois, even though white-nose syndrome has pushed this same bat to globally Endangered by wiping out huge hibernating colonies farther east. Illinois hasn’t reported that kind of collapse, at least not yet in this record set.
Full species profile
