Foraging ecology of Leisler's bat (Nyctalus leisleri) at two sites in southern Britain

Abstract

Leisler's bat Nyctalus leisleri was studied at sites around Bristol and Kent in southern Britain. Its diet was studied by faecal analysis, and habitat use was monitored by radio-telemetry and time-expanding bat-detectors. The diet, which varied between the two sites and also with the season, consisted primarily of small Nematoceran Diptera plus smaller numbers of Coleoptera and Lepidoptera. Foraging ranges were relatively large – bats flew a mean maximum distance of 4.2 km from the roost. Minimum area convex polygons enclosed an average of 7.4 km², but were up to 18.4 km². Bats significantly preferred foraging in areas of woodland and along scrub-lined roads in Kent, but over pasture around Bristol. Urban and arable areas were avoided at both sites. Bat-detector transects showed a significant preference for bats to forage along woodland margins.