The Barbastelle (Barbastella barbastellus) is a very elusive bat with very few records from Britain each year. It is recorded from a wide area of southern Britain though it is very unpredictable in its occurrence and only 4 breeding colonies are known in the UK. It is also found in most of western Europe (excluding Scotland, Ireland and most of Scandinavia).

It is a medium-sized species with blackish fur on the back and the tips of the hairs may be pale cream or yellow, giving a frosted appearance. The underfur is grey-brown, often with pale tips. The ears are black, short and broad and joined across the forehead and with its rather squat face this gives it a very distinctive "pug-like" appearance.

Barbastelle bats are vulnerable to the decline of woodland, which results in the loss of suitable feeding habitats and hollow trees for roosting. They are susceptible to pesticides, especially those used as remedial timber treatment chemicals. Disturbance and vandalism of their hibernating sites, caves and tunnels, is an additional threat.

flight & ultrasound

Barbastelle bats emerge in early dusk and hunt low over water and at tree top height along woodland edges and gardens. They fly fast and skilfully, although are rarely heard because their echolocation calls are very weak. Their main echolocation calls range between 40 - 45 kHz with a peak at 43 kHz.

breeding

In summer females segregate and form small maternity colonies; males usually remain solitary or in small groups. The females are sexually mature in their second year. Barbastelle bats are very sensitive to disturbance.

summer roosts

Roosts are mostly in hollow trees and buildings. Other recorded roost sites include under tree bark and amongst exposed tree roots.

winter roosts

In winter they occasionally appear close to the entrances of caves during prolonged cold spells. As they are a cold-resistant species, this suggests that they are not dependent on such underground sites but make use of them in periods of particularly cold weather. Winter groups are commonly of mixed-sex.