Notes on the Ecology of Myotis keenii (Chiroptera, Vespertilionidae) in Eastern Missouri

Data collected on over 2000 individuals supplemenent the information available on the ecology of Myotis keenii in eastern Missouri. Observations on chemical-light tagged bats suggested that foraging areas were among trees in hillside and ridge forest. Banding data (47 returns from 945 banded) indicated a strong fidelity for a specific hibernaculum. Myotis keenii hibernates from October to March. Males and females have a prehibernation fat deposition period lasting from August to October. Females are significantly heavier than males most of the year. Copulation occurs prior to entering hibernation. Females disperse from caves after hibernation to noncave maternity sites where partuition occurs in late May or early June. Most males also leave hibernacula in spring and summer. An unusually large male group movement and use of one cave during June were documented 2 years in succession.