Variation in Diet of the Gray Bat (Myotis grisescens)

During spring and summer 1991, a total of 1,476 fresh fecal pellets of gray bats, Myotis grisescens, was collected at Blowing Wind Cave, Jackson Co., Alabama. Fourteen orders of Insecta, unidentified Insecta, an unknown organism (possibly Insecta), two orders of Arachnida, and hair from gray bats were recovered; in decreasing order, the most common taxa were Lepidoptera, Diptera, and Coleoptera. Food categories exhibited significant variation among sampling sessions, nights within sampling sessions, and hours within sampling sessions. When quantity of each food category in fecal pellets was compared with quantity of potential prey available for consumption, there was no statistically significant correlation. There was significant variation in diet over time, but bats did not select prey in proportion to availability.