Illinois has logged only 47 gray bat reports, and NatureServe ranks the species S1, critically imperiled, in the state, a far more precarious standing than its global Vulnerable listing. That gap makes sense for a bat that depends on a small number of specific caves for roosting; disturb or lose the right cave, and a state’s whole record trail can thin out fast.
Nearly all of those reports, 42 of the 47, fall in July, when gray bats are most likely to be caught foraging over rivers and reservoirs at night rather than hidden deep in a roost. That lopsided pattern says more about when surveys tend to catch bats in flight than about the species vanishing for the rest of the year. Given how few records exist and how tightly this bat is tied to intact cave habitat, any single Illinois report is genuinely notable.
