Barbastelle bat  (Barbastella barbastellus)

The 2000 IUCN Red List classifies this species as Vulnerable (VU-A2c). European populations are listed under Annex II of The Bonn Convention (1), Annex II of the Bern Convention, and Annexes II and IV of the EC Habitats and Species Directive. In the UK it is protected under Schedule 5 of the Wildlife and Countryside Act 1981, and Schedule 2 of the Conservation Regulations 1994 (3).

This rare medium-sized bat has a short nose, small eyes and wide ears with a triangular shaped tragus. It has long silky fur, dark brown to black in colour with whitish tips giving the bat a frosted appearance (2). The wings are broad with grey-brown or black-brown membranes, and the tail membrane is extremely large (2). The scientific name Barbastella derives from the Latin for 'star beard' (4) (5); and refers to the delicate beard of frosted white hairs radiating out from the lower lip (6).

The barbastelle bat is widespread but rare throughout Europe (2) from England east to the Caucasus Mountains (2). In the UK it is restricted to southern England and Wales (7). Only one maternity roost and under 30 hibernation sites are known (3).

Mainly a broadleaved woodland species, this bat roosts in old buildings and trees in summer and hibernates in hollow trees, in tunnels (8) or underground. In some areas woodlands close to water may be important (3).

Barbastelle bats emerge at early dusk. They hunt low over water or at tree-top level with fast agile flight (2). They hunt small insects such as flies and moths on the wing (2) but can also glean spiders and insects from plants (3). They only take delicate small prey items, as the mouth has a narrow gape and the teeth are relatively weak (2). In their second year, females become sexually mature, and mating occurs in autumn. The females gather in maternity roosts or nurseries and give birth to one, or rarely two offspring. During this time, males form small groups and live away from the nurseries (2).

The UK population is estimated to number around 5000 individuals, the overall trend in numbers is not known (3). The threats to the barbastelle bat are not fully understood (3), however it is very sensitive to disturbance (2). Factors such as the loss and fragmentation of the preferred ancient broadleaved woodland habitat and loss of roost sites will be likely to have strong negative effects on the population. Furthermore, insect prey availability may have been greatly reduced by fertiliser use and intensive grazing leading to a loss of habitat complexity and associated diversity (3).

The barbastelle bat is a priority species under English Nature's Species Recovery Programme and has a Species Action Plan that aims to enhance the current population by improving the age structure of woodlands to maximise roosting and foraging sites. Some of the hibernation sites occur in SSSIs or have been protected by grilling. The National Bat Monitoring Programme aims to determine base-line data on this species, and in Norfolk, Surrey and Devon, ongoing research aims to find roosts and determine more detailed habitat requirements of the barbastelle bat (3).

For more on British bats see the Bat Conservation Trust:
http://www.bats.org.uk/

The Vincent Wildlife Trust:
http://www.vwt.org.uk/index.php

Information authenticated by the Bat Conservation Trust:
http://www.bats.org.uk/

• Hibernation: a winter survival strategy characteristic of some mammals in which an animal's metabolic rate slows down and a state of deep sleep is attained. Whilst hibernating, animals survive on stored reserves of fat that they have accumulated in summer. In insects, the correct term for hibernation is 'diapause', a temporary pause in development and growth. Any stage of the lifecycle (eggs, larvae, pupae or adults) may enter diapause, which is typically associated with winter.
• Tragus: a soft cartilaginous projection extending in front of the external opening of the ear. In bats it is thought to aid in the location of prey by generating many echoes, but the precise way in which this works is unknown.

1. UNEP-WCMC (April 2002): http://quin.unep-wcmc.org/
2. Schober, W. & Grimmberger, E. A (1989) Guide to Bats of Britain and Europe. The Hamlyn Publishing Group, London.
3. UK Biodiversity. Species Action Plan (April 2002): http://www.ukbap.org.uk
4. Ian Turner. Pers. Comm.
5. Latin Dictionary and Grammar check (April 2002): http://www.nd.edu/~archives/latgramm.htm
6. Pers Obv.
7. Bat Conservation Trust (April 2002): http://www.bats.org.uk
8. Bat Conservation Trust (2002) Pers. Comm.