I determined foods eaten by bats at Prairie Creek, Vigo County, Indiana, to test the null hypothesis that insectivorous bats eat primarily whatever is available. If bats eat what is available, then all bats taken at the same time and place should eat the same foods. I collected fecal samples from 486 bats of 8 species from 1993 through 1997 in a 650-ha deciduous forest in the Wabash River flood plain. Eptesicus fuscus and Nycticeius humeralis fed heavily on coleopterans, followed by hemipterans in E. fuscus and homopterans in N. humeralis. Lasiurus borealis fed most heavily on lepidopterans, followed by coleopterans and homopterans. Pipistrellus subflavus fed approximately equally on homopterans, coleopterans, and dipterans. The main foods were similar for Myotis sodalis, M. lucifugus, and M. septentrionalis: dipterans 1st, followed by lepidopterans, trichopterans, and then coleopterans in M. lucifugus and by coleopterans and then lepidopterans in the other 2 species. It is clear that bats at Prairie Creek selected from among the available foods. Myotis septentrionalis, a gleaner, did not eat foods appreciably different from other bats in the same genus.