Barbastelle

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, using a two-part call, as described in the paper "Echolocation by the Barbastelle bat" (pdf 202Kb). The 43 kHz call is generally weak and often inaudible or absent. However, the main call is much louder and is lower in frequency, with a peak frequency around 32kHz. It is said to resemble a sort of "wood-block" sound.

  Barbastelle call on a Heterodyne bat detector

  Barbastelle call on a Time Expansion bat detector

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.

Description
Head and Body Length	45 - 58 mm
Forearm Length	36 - 44 mm
Wingspan	260 - 290 mm
Weight	6 - 13 g
Colour	Fur is blackish on the back and the tips of the hairs may be pale cream or yellow, giving a frosted appearance. Squat face gives a very distinctive 'pug-like' appearance.
Life Cycle
Mating Period	Autumn and winter.
Maternity Colonies	Young: 1 born mid-June.
Colony Size	10 - 20 females, rarely up to 100.
Longevity	23 years.
UK Status	Rare.
Habitat and Food
Summer Roosts	Hollow trees and buildings.
Winter Roosts	Caves, tunnels, trees.
Feeding Habitat	Wooded river valleys, over water and woodland edges.
Food	Lepidoptera, diptera, small beetles. They have small, weak teeth and are unable to bite through the shells of large beetles.

futher reading

Detailed species notes on the Barbastelle by Jens Rydell & Wieslaw Bogdanowicz (American Society of Mammalogists, 1997) (pdf, 988Kb)