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Home / Whiskered bat

Myotis mystacinus

Description and identification

The whiskered bat is one of three small Myotis species in the UK. It is very similar to the two other small Myotis, the Alcathoe bat and the Brandt’s bat; the latter of which is found in Nottinghamshire, whilst to date the former has only been found in North Yorkshire, Sussex, Surrey and Kent. It is only really possible to tell apart these three bats (the ‘WAB’ bats) when holding them in the hand, and it comes down to differences in their coat, teeth and male genitalia. Often a DNA sample needs to be taken to confirm their identity. Whiskered bats have a dark face and ears, with a long tragus. They look shaggy and have dark brown back hair with variably grey sides and a paler tummy.

The echolocation calls of the whiskered bat are short (3-6ms) typically ranging from around 85 kHz down to 32 kHz. A lot of experience is required to separate the whiskered from other Myotis species based on sonograms alone and even then, identification is unlikely to be certain.

Status and distribution

The whiskered bat is found across England, Wales and southern Scotland, where it is widespread but rare. It is widespread in Ireland but is even rarer there.

There are several known whiskered bat roosts in Nottinghamshire including several maternity roosts in buildings. A small number of tree roosts have also been found in the county.

Roosts

Whiskered bat forms maternity colonies of 20-60 females, where they raise their young in cavities in buildings, such as behind timber cladding. They will roost in trees, favouring crevices behind flaking bark29, although until very recently, they had not been recorded roosting in bat boxes in Nottinghamshire. Owing to the difficulty in distinguishing whiskered bat from Brandt’s bat, we still do not know for certain which of these two species has been found roosting in an NBG bat box scheme, set up in Colwick Park.

Solitary roosts of male and non-breeding female bats use a wide range of roosting locations both in trees and on buildings. They have been found beneath ridge tiles and behind bargeboards and in a wide range of tree crevices.

In winter whiskered bats are generally recorded hibernating in humid caves, disused railway tunnels and churches but in Nottinghamshire their winter refuges remain largely undiscovered.

 Food and foraging

Whiskered bats show a preference for hunting along woodland edges, orchards and in parkland where they exploit mainly flying insects such as mosquitoes, midges, craneflies, small moths and lacewings. Analysis of their diet shows that whiskered bats also feed on day-flying insects, indicating that they are able to ‘glean’ or pick insects from vegetation.