July stands out in Illinois big brown bat reports, with sightings roughly doubling compared to spring and holding at that level into August. Summer is when this bat is most actively hunting and roosting close to people, in barns, attics, and rock crevices, so warm-month records likely track both its own activity and how often someone notices a bat overhead.
Shawnee National Forest, Starved Rock State Park, and the Upper Mississippi River refuge lands make up the state’s main reporting areas, a spread that covers rocky bluffs, mature forest, and river corridor within one state’s records. With 249 records since 2000, big brown bats rank among Illinois’ better-documented bats.
It’s native to Illinois, and NatureServe rates it secure both statewide and globally, a simpler status than some of the state’s more vulnerable bats carry.
Full species profile
