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Home / Bats in Nottinghamshire / Barbastelle


Description and identification

The barbastelle is Britain’s most distinctive bat species. It has a pug-like face with near upwards-facing nostrils and broad, angular ears that almost encompass the eyes. The ears are joined in the middle at the base, have a characteristically-shaped tragus, and usually also have a small lobe on the outer edge. The barbastelle has almost black skin and fur, often with creamy white tips, which can give the bat a frosted appearance.

The echolocation calls of barbastelle are quieter than most other British bat species. They use two distinct call types: lower frequency calls which are FM (see glossary for definitions of calls) and have a peak frequency (of maximum energy) at about 32-33 kHz; and higher frequency calls which are qCF/FM and have a peak frequency at about 42 kHz. Lower calls are emitted from the mouth and are usually louder than the higher frequency calls, which are emitted from the nostrils.

The lower call at 32-33 kHz is usually diagnostic of barbastelle. When heard on a heterodyne bat detector, barbastelle echolocation calls are often likened to the sound of castanets.

Status and distribution

The barbastelle is one of the UK’s rarest mammals. It is currently only found in central and southern England and Wales where, despite some recent discoveries, there remain very few known breeding colonies for this species. Population declines and scarcity across most of its wider European range also mean the barbastelle and its habitats are afforded legal protection above most other European bat species.

The barbastelle was first recorded in Nottinghamshire in 2011 on an NBG transect near the River Trent. Recordings confirmed the presence of at least one foraging bat. Later that summer, a small number of other recordings were also sent to the bat group from a site approximately 8km away. In 2013 recordings were then also verified from a site to the west of the county on the border with Derbyshire.

The East Midlands is currently at the northern extent of the barbastelle’s UK range and it is the bat species of highest conservation concern in this region. The Nottinghamshire Barbastelle Project (NBP) was therefore initiated in 2015 to understand more about the distribution and conservation status of this species in and around the county.

Barbastelles have been recorded in 10 hectads in Nottinghamshire.

Roosts

Barbastelle typically prefer to roost in naturally damaged and decaying trees in old growth (ancient) unmanaged broadleaved woodland, often with a high proportion of oak Quercus spp. and standing deadwood, and sometimes with a holly Ilex aquifolium understorey. In summer, breeding female barbastelles move regularly between multiple tree roosts, often roosting behind lifting bark and other cracks and crevices. Most roosts located during radio-tracking surveys carried out on the NBP in 2016 and 2017 were found behind lifting bark on old oak trees, including Nottinghamshire’s first maternity roost for this species.

At other times of the year, barbastelles will roost in trees, old buildings, caves and rock fissures, although usually in low numbers. There are also a handful of UK records of barbastelle occupying atypical roosts within buildings, such as behind hanging tiles and bargeboards. Nottinghamshire’s first roost record for this species comprised one such roost (see below) used by a radio-tracked female barbastelle in the spring of 2016. In August of the same year a single bat was also found in a Nottinghamshire building undergoing restoration.

This species will hibernate in disused railway tunnels, caves, mines and bunkers where it is often found in the coldest areas.Barbastelles will occupy bat boxes which replicate their usual crevice-type tree-roosting sites in suitable surrounding woodland. A bat box scheme such as this in central Nottinghamshire has been used by one or two barbastelle bats regularly since 2016.

Food and foraging

Barbastelles predominantly feed on moths, although lacewings, caddis flies, small beetles and true flies are also eaten.

Barbastelles typically forage in and over riparian habitat and meadows (including those on floodplains), in broadleaved woodland and along mature hedgerows, field margins and tree lines. However, the species has also been recorded foraging along rides in conifer plantations, over a willow holt and a sewage farm on the NBP.

Barbastelles use of foraging areas varies within and between seasons (including in winter), probably in response to prey availability but also possibly influenced by their reproductive status. They prefer to commute between roosts and foraging habitats via naturally covered and dark, linear woodland rides and landscape features but they will cross open countryside under cover of darkness. Barbastelles have been recorded commuting over 20km to favoured foraging patches although the radius of their Core Sustenance Zone (CSZ) is usually between 5 and 7km.

Sample echolocation calls

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Listen: Time expansion (10x) recording of a Barbastelle from a woodland path (Michael Walker)

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Listen: Time expansion (10x) recording of a Barbastelle from a hedgelined road in the village (Michael Walker)

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Listen: Time expansion (10x) recording of a Barbastelle from a woodland path (Michael Walker)