Pipistrelle bats gather together in colonies throughout the year. During the summer they congregate in large colonies, roosting in trees (under bark or in hollows), buildings such as churches, and rock crevices.
Favourite summer roosting places are small, warm spaces behind tiles or weather-boarding on a south-facing wall. The pipistrelle is so tiny that it can squeeze through gaps only 15mm wide.
The bats sleep lightly during the day and usually begin streaming out from their roost 15 - 30 minutes before sunset to hunt for insects. In midsummer they regularly appear during the daytime. Each bat spends 2 - 5 hours per day away from its colony, using temporary roosts in between short feeding flights.
Pipistrelle bats hibernate during the winter, from about mid-October. The colony gradually stops feeding and finds a suitable hibernation site, such as a church roof or bell tower, a quiet place in a large house, a hollow tree or rock crevice. Each bat hangs or wedges itself head down, gripping the surface with its feet. During warmer spells, the pipistrelle will wake up and fly out to look for food. Winter colonies sometimes number 1000 bats - one cave in Romania is a refuge for an estimated 100,000 pipistrelles!
Read More: Protecting the Pipistrelle