Do bats breed like mice?
No. Each adult female bat has only one (occasionally two) young in a given year and as pipistrelle maternity roosts are comprised almost entirely of adult females, even if all their young survived to adulthood, a colony could only increase by a theoretical maximum of around 50% per annum (half of the young born are males and these will roost separately in future years). In practice, the actual increase in the colony size is less than this, as not every female in the roost is likely to be pregnant and not all the youngsters will survive.
