NatureServe ranks the Indiana bat S1, Critically Imperiled, in Illinois, about as serious as a state rank gets, and the species is also protected nationally as federally endangered. Illinois records cluster around Shawnee National Forest, Midewin National Tallgrass Prairie, and refuge lands along the upper Mississippi, places with the limestone caves, bluffs, and river-corridor forest this bat needs for its two very different seasonal homes.
The state’s record is thin, just 26 reports since 2000, and the most recent confirmed sighting on file dates back to 2014. That gap says more about how hard this small, cave-roosting bat is to detect than about whether it’s still present; Indiana bats winter in a handful of hard-to-reach caves and spend summer scattered under loose bark, well out of casual view.
What records exist peak sharply in April, when bats leave hibernation and move toward summer roosts. Nationally, white-nose syndrome, a fungal disease that disrupts hibernation, has devastated winter colonies of this species, turning a slow breeder, one pup a year at most, into one of the country’s most urgent bat conservation concerns.
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