Aspects of the conservation biology of the noctule bat (Nyctalus noctula)
The present study primarily examined habitat selection in the noctule bat by comparing used resources with samples of available resources. The distribution of individual bats of different reproductive status was also investigated, in relation to resources, to enable the prediction of future events under different habitat management scenarios. Individual bats were also radio tracked to determine foraging and roosting habitat preferences in a cultural landscape. Noctules consistently preferred to forage over broadleaved woodland and pasture rather than arable land and moorland. A comparison of habitat use and foraging activity demonstrated that non-lactating bats used less preferred habitats significantly more than lactating bats. However, there was little difference in the timing of foraging activity or in the distances travelled to foraging grounds between the two groups. Roosting requirements were identified using data from three separate study sites and intraspecific roosting behaviour was investigated at the radio tracking site. Noctules consistently selected old woodpecker holes that were larger, further from the ground and in more open situations. Lactating bats changed roosts less frequently and generally occupied one specific roost, which was larger than the other roosts used by the same colony. The echolocation calls used by noctules are particularly suited to monitoring using bat detectors. Formal evidence that noctule calls could be accurately identified from field recordings was obtained by comparing the calls from tracked bats with calls recorded from Leisler's bats.