Bat (Natterer's) - Breeding

During the summer, female Natterer's bats gather together to form nursery colonies in hollow trees or the roofs of houses. After a pregnancy of fifty to sixty days, the female has only one baby (or very rarely twins), born in June or July. The young bat pup can fly by the time it is four weeks old. Young Natterer's bats do not have the white underparts of the adult - they are greyish-brown all over during their first year.