A woodland specialist, Bechstein’s bat are elusive rarely heard on bat detectors and difficult to find in trees – what a nightmare!

Bechstein's bat in woodpecker hole

Anatomy

Bechstein’s bat is a medium in size, weighing between 7 and 10 grams, with huge ears that make it relatively easy to identify. The tragus (structure in the centre of the ear) is about half the length of the ear. It has reddish-brown fur on its back, and a bright beige or grey underside. Learn how to identify Bechstein’s by watching this video.

The face glands of this species produce individually recognisable secretions, from which the members of a colony are able to recognise each other.

Ecology

Feeding

Like all UK bats, Bechstein’s bat is insectivorous. The mainly eat woodlice, moths, beetles, crane-flies, lacewings and spiders. They frequently feed on the ground, allowing them to catch harvestmen, earwigs, caterpillars, bush crickets, bugs, ground-beetles, centipedes, aphids and caddis flies.

Their huge ears give them fantastic hearing, meaning they are therefore able to locate their prey by the practically silent scuffling sounds the insects make as they move. They take regular breaks while hunting, and can be seen hanging in trees to have a rest.

Bechstein’s bats have a particularly quiet echolocation, making them hard to detect

Bechstein’s bats are very agile and can hunt very close to vegetation, often plucking their prey directly from it. They can hunt anywhere between tree canopy and the forest floor.

Reproduction

The nursery groups get together in late April and remain together until late July. They can contain up to 80 females, although groups of 10-50 are more common. Males are solitary during the summer.

Bechstein’s bat live in trees during the summer but spend the winter underground. From August, adult Bechstein’s bats leave the woodland for underground sites (e.g. caves, mines, tunnels). Gathering at these underground sites allows them to mate with animals from different colonies; maintaining a diverse gene pool and avoiding inbreeding. As bats mature, females remain within their colony, whereas males will disperse.

Young bats are able to fly and forage for themselves at just six weeks old

Location and habitat

Bechstein’s bats are only found in the south of England and south east Wales in the UK, but are widespread throughout central and eastern Europe. They are usually found in deciduous and mixed woodlands, both in lowland and mountainous regions. They are frequently found in woodpecker holes, so a constant supply of deadwood is required.

Predators

Bechstein’s bats need to watch out for various woodland predators such as stoats, owls and woodpeckers.

Want to learn more about how to survey trees for Bechstein’s bats? Watch this presentation to learn more.