Responses of Myotis lucifugus (Chiroptera: Vespertilionidae) to calls of conspecifics and to other sounds

We played a variety of sounds to Myotis lucifugus occupying a New Hampshire barn in August 1975 using a recording and playback system which reproduced sounds from 15 to over 100 kHz. The M. lucifugus responded to 'distress' calls of conspecifics but not to other noises, specifically feeding sounds of Myotis spp., continuous 45 kHz sound, and 'distress' cries of Eptesicusfuscus. Responses to the 'distress' cries of conspecifics included general increases in levels of activity and low-frequency vocalizations (audible to us), and swooping flights near the ultrasonic loudspeaker from which the sounds eminated. When a dead M. lucifugus was suspended above the speaker and the 'distress' calls of this species were presented, bats circled close to the carcass; they did not respond in this way when other sounds were presented or during controls when the carcass was present.