RELATIVE ACTIVITY AND OCCURRENCE OF BATS IN SOUTHWESTERN ONTARIO AS DETERMINED BY MONITORING WITH BAT DETECTORS

Activity and occurrence of bats was studied in southwestern Ontario us ing bat detectors on 10 ni hts between 10 June and 10 July 1991. Four species, Big Brown Bar, Eptesicus fuscus, Red Bat, Lasiurus borealis, Hoary Bat, L. cinereus, and small brown bats, Myotis spp. were detecte d during the survey. Lasiurus cinereus was the most commonly encounter ed species and bat activity was markedly different from that depicted by mist net captures or museum records.