Devon Mammal Group

Barbastelle Bat

Barbastelle Bat

Common Names

Barbastelle Bat; Western Barbastelle; 'Barbie'

Scientific name and classification

Family: Vespertilionidae
Genus: Barbastella
Species: Barbastellus

Barbastelle Bats are named for the hairs, frosted white, which stick out from their lower lip and body. Barbastella is derived from the Latin, meaning 'star-beard'.

Conservation/protected status

Our Barbastelle bat is one of the UK's rarest mammals and is found largely in the South-West and Wales, making conservation in Devon all the more important for this species.

In 2000, the IUCN red list of threatened species classified the Barbastelle as 'vulnerable'. In the most recent edition, the Barbastelle is unfortunately 'near threatened', which means the population trend is decreasing.

The barbastelle is protected or listed under:

  • Annex II of The Bonn Convention
  • Annex II of the Bern Convention
  • Annexes II and IV of the EC Habitats and Species Directive

In the UK...

  • Schedule 5 of the Wildlife and Countryside Act 1981
  • Schedule 2 of the Conservation Regulations 1994

The Barbastelle has a Species Action Plan in both the Dartmoor and Teignbridge Biodiversity Action Plans (BAPs).

Current and local status

 

Barbastelle sightings in Devon

Barbastelle sightings in Devon

Two new maternity roosts have been found in South Devon's broadleaved woodland, on the edge of Dartmoor National Park. This is a tremendous find as previously there was only one such roost known here. There are roosting sites and maternity sites found in the Bovey, Dart and Teign valley systems. Also possibly use Chudleigh caves and woods SSSI, part of South Hams SAC. The bats forage all down these systems across the floodplains and woodland, and have been tracked as far South as the coast.

Distribution maps

(Image: Bristol University Biology dept)

(Image: Bristol University Biology dept)

(Image: Bristol University Biology dept)

(Image: Bristol University Biology dept)

Barbastelles are rare creatures, with populations being found largely in the South-west, Wales and some in Norfolk.

General Description

The Barbastelle is a medium sized bat of about 4-6cm (1.4–2.6'') along the body. The tail membrane is large, being approximately the same length and the wings are broad when open with a dark grey/brown or brown/black membrane.

(Image:Bristol University Biology dept)

They have silky, dark brown/black fur. Many of the hair strands have white tips, especially on the lower lip, making the whole bat look slightly frosted.

Seen from the front, the Barbastelle has a pug-like appearance, with short, wide ears meeting in the middle of the head (complete with triangular tragus), a short nose and small eyes.

Surveying the Barbastelle

Only people who are trained and hold licences are allowed to handle bats in the UK. Barbies have been most recently researched here in Devon by a PhD student from Bristol University, who has been surveying their behaviour and roosting sites using harp traps, mist nets and acoustic lures.

Harp traps use flexible, vertically strung ropes, into which the bats fly before falling into a special net.
Mist nets are large nets made of thin, flexible artificial materials perfect for catching bats without causing harm. These are strung up between trees or other structures.
Acoustic lures are sound bites used to attract the bats to a certain area where they are to be caught. The bat's social call is usually synthesised and played out (with mixed success at attracting Barbastelles!)

Once caught, barbastelles are tagged with tiny radio transmitters, complete with aerials, so their progress on flight can be tracked and recorded. The transmitters weigh only about 0.35g and fall off after roughly ten days, so don't impede flight.

Habitat

Barbastelles commonly occupy wooded river valleys with water present (such as the one in the picture below). This habitat provides space to roost and forage. They use mature trees, caves and sometimes underground tunnels or buildings as roosts and both water bodies and woodland as areas over which to forage.

Barbastelle habitat

Example of habitat (Image: Bristol University Biology Department)

Roosting and maternity sites are protected under law to help us keep them safe, so people cannot disturb them there. Finding a Barbastelle roosting is extremely difficult anyway, since they tuck away into small crevices. However, you may be lucky enough to spot a Barbastelle at dusk while they feed, silhouetted against the water of these rivers.

Life history traits

The oldest Barbastelle ever known was 23 years old! Females become sexually mature at two years old. They mate during the autumn, often in hibernaculum, hibernate during the winter months (October to March) and then settle down for the warmer months into summer roosts where the young are born in June. Mothers give birth to one young bat, which they wean for six weeks before they learn to hunt and fend for themselves.

Behaviour

During the day bats rest. Barbastelles emerge at dusk to forage for insects and small moths and beetles. They avoid larger prey as their teeth are fairly soft. Like all bats they are skilful hunters, using echolocation to find and track their prey in the dark. They are active sporadically through the night, flying low over bodies of water and grassland and high over nearby woodland.

Foraging areas (Image: Bristol University Biology Department)

Foraging areas (Image: Bristol University Biology Department)

Current research

PhD research (Bristol University) is being carried out in Devon to further determine dietary and roosting ecology. The research is designed to identify the preferences of Barbastelles and inform conservation management. There is little data available on Barbastelles, relative to other bat species, but in the UK several projects are being formed to rectify this situation. More information can be found on these at the UK Biodiversity Action Plan website, or by using the following link:

http://www.ukbap-reporting.org.uk/uploaded/national_plans/2cc5391d84f9461eaccee4b136434edb.doc.

Links

The Devon Bat Group: http://www.dbg.me.uk/

The Bat Conservation Trust: http://www.bats.org.uk/pages/uk_bats.html

Barbastelle Species Action Plan under UK Bioodiversity Action Plan: http://www.ukbap.org.uk/UKPlans.aspx?ID=133