When the weather gets warmer, usually in early summer, pregnant female bats gather together in warm, safe places to have their babies. These roosts are called maternity roosts. Some groups of bats return to the same site every year.
A bat’s pregnancy lasts between six and nine weeks. The length of the pregnancy depends on the species and can be influenced by weather, climate and availability of food. Bats usually give birth to a single baby (called a pup) each year. They keep their babies close and nurture them carefully. The young bats are suckled by their mothers for four to five weeks until they are old enough to fly. They then begin to venture out from the roost to forage for food.
Bats are very sensitive during the maternity season and may abandon their young if they are disturbed. As warm, dry indoor spaces like lofts are often ideal for maternity colonies, it’s very important to check for bats before carrying out any building or remedial work.