Prey Location by 12 Australian Long-Eared Bats, Nyctophilus-Gouldi and N-Geoffroyi

Abstract

The sensory abilities of two species of long-eared bats were studied in captivity. Prey location trials demonstrated that Nyctophilus spp. may employ a diverse array of sensory cues, including use of prey sounds, vision and echolocation. Insects were readily captured from substrates, confirming the hypothesis that Nyctophilus can feed by gleaning, but flying insects were taken with equal ease, showing that these bats are flexible not only in their sensory behaviour but also in their mode of prey capture. Echolocation was not used for orientation except when in an unfamiliar environment, and even then was 'switched off' on approaching fluttering prey. Nyctophilus used prey sounds to capture flying insects as well as those on substrates, a feeding technique not previously reported for gleaners. Visual cues were used to capture insects from the air, but not from substrates. This mode of feeding is an effective replacement for echolocation, including the 'feeding buzz', and thereby circumvents the evasive responses of sonar-sensitive insects.