Roosting behaviour and phenology of the Lesser horseshoe bat (Rhinolophus hipposideros) in a breeding colony in Sintra, Portugal

Almost all bats are exclusively nocturnal. However, the activity patterns throughout the night can differ between species and also within the same species from place to place. Rhinolophus hipposideros (Bechstein, 1800) has suffered a severe decline in many countries along its distribution area, including Portugal. In this study we aimed to describe the roosting behaviour during spring, summer and autumn of one of the largest maternity colonies of R. hipposideros known in Portugal. We analysed roost occupancy, activity patterns inside the roost, birth periods, and post-natal behaviour. We also tested the influence of ambient factors on the patterns of roost use. All information was obtained through the analyses of video recorded using cameras placed inside the roost, while climatic data were gathered using a meteorological station. We found that this roost has higher occupation during August and that in October it is only occupied during the night. Females gave birth from late May to early June, and in August juveniles became independent and undistinguishable from the adults. This colony presented a bimodal pattern of activity throughout the months of the study, which seems to be related with sunset and sunrise. Our results indicate that individuals of this colony prefer higher temperatures, but low humidity and wind speed to leave the roost.