Morphological Description

Life History

Distribution

Habitat

Roost Sites and Roosting Patterns

Emergence and Flight Pattern

Foraging Behaviour

Echolocation Calls

Status and Protection

• Dorsal fur is medium to dark grey, possibly with a slight brownish tinge. Ventral fur is very pale grey.
• Fur is long.
• Ears are approximately three quarters of the length of the head and body and are longer than 30mm.
• Can be distinguished from the brown long-eared bat by the width of the tragus. The tragus of the grey long-eared bat is greater than 5mm at its widest point.
• Can also be distinguished from the brown long-eared bat by the length of the thumb. The thumb of the grey long-eared bat is less than 6.5mm.
• Average weight (as given by Greenaway & Hutson, 1990) 7-14 g.

The diagram below gives important average body measurements for grey long-eared bats (Greenaway & Hutson, 1990).

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Life History

• Mating occurs from September to October.
• A single young is born in June or July (Swift, 1991b).
• Maximum age recorded in Europe is 14.5 years (Schober & Grimmberger, 1989).

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Distribution

Mainly found in the south and south east of England.

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Habitat

•  Relatively little is known about the habitat of the grey long-eared bat but it is probably similar to that of the brown long-eared bat.

•  Warm valleys and small, open woodland. Often associated with villages and towns.

•  The photograph on the left shows a typical habitat of grey long-eared bats.

Roost Sites and Patterns

• Summer roosts: Nurseries are found from March (Swift, 1991b). Roost in buildings in attics singly or in small groups in crevices or timbers. May roost with lesser horseshoe bats.
• Winter roosts: Hibernate from October in warm regions of caves and similar environments (Greenaway & Hutson, 1990). May prefer exposed positions to underground sites and the lack of suitable warm sites may be the reason for the limited distribution of grey long-eared eared bats in Britain (Swift, 1991b; Greenaway & Hutson, 1990). Usually found singly hanging freely from the wall but may also roost in crevices. May roost with brown long-eared bats.

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Emergence and Flight Pattern

•  Emerges in the dark and forages sporadically throughout the night.

•  Flight is low, 2-5m above ground level (Swift, 1991b).

•  Flight is agile and skilful.

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Foraging Behaviour

• Forages close to the roost in open spaces and occasionally around street lights. May sometimes glean insects from foliage but more often catches prey in free flight.
• The diet of grey long-eared bats mainly consists of Lepidoptera, including many tympanate species. Diptera, predominantly woodland species, are also taken (Vaughan, 1997).
• May use feeding perches.

Marked in blue on the diagram above is a typical foraging path of grey long-eared bats (based on Russ, 1999).

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Echolocation Calls

To listen to the call of the grey long-eared bat click here (recorded in Tuscany, Italy, by Dr Danilo Russo).

Size of sound file: 22.8 KB

Average values for a grey long-eared bat echolocation call, as given by Vaughan et al. (1997), are listed below:

Interpulse interval: 104.2ms

Call duration: 1.7ms

Minimum frequency: 29.8kHz

Maximum frequency: 62.5kHz

The spectrogram on the left shows clear frequency modulation, with the call beginning at high frequency and ending at a lower frequency.

The power spectrum on the left shows that the maximum power of the call is at a frequency of approximately 50 kHz.

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Status and Protection

• The British pre-breeding population was estimated at 1000 in 1995 (all in England ) (Harris et al., 1995).
• Very rare in England.
• Grey long-eared bats are at low risk of extinction worldwide (IUCN status, 2001).
• Nursery roosts and habitats should be protected.
• May be threatened by timber treatments and pesticide use.

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