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 grey-brown with red-brown tips. Ventral fur may be very pale and ranges from dingy white to yellow-grey.
• Fur is thick, long and dishevelled.
• Juveniles up to 12 months are dark grey and look very similar to whiskered bats.
• Brandt's and whiskered bats are extremely similar and therefore easily confused. The teeth can be used to distinguish the two species. On the lower jaw of Brandt's bats the third premolar (P3) is greater than half the size of the second premolar (P2). On the upper jaw the protocone of P4 is large and taller than P3 (see diagram on left).
• Adult male Brandt's bats have a club-shaped penis while the whiskered bat has a thinner parallel-sided penis.
• Average weight (as given by Greenaway & Hutson, 1990) 4.5-9.5 g.

The diagram below gives important average body measurements for Brandt's bats (Greenaway & Hutson, 1990).

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Life History

• Mate in autumn, including hibernation period.
• In Europe a single young is born between mid-June and mid-July (Schober & Grimmberger, 1989).
• Maximum age recorded in Europe is 19 years 8 months (Schober & Grimmberger, 1989).

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Distribution

There is some uncertainty over the distribution of Brandt's bats because they are not easily distinguished from whiskered bats. Currently Brandt's bats are thought to be widespread throughout England and Wales and especially common in north and west England.

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Habitat

•  Woodland and hedgerows, often near bodies of water.

•  The photograph on the left shows a typical habitat of Brandt's bats.

Roost Sites and Patterns

• Summer roosts: In Europe nursery roosts are found from May and usually contain 20-60 females (Schober & Grimmberger, 1989). Mainly roost in buildings (preferentially old buildings), possibly also in trees.
• Winter roosts: Found in crevices in colder regions of caves (often near the entrance) from October to February/March. Brandt's bats are either solitary or found in small groups over winter. May from larger aggregations with other species.
• Occasionally found in bat boxes.
• It is often very difficult to distinguish Whiskered and Brandt's bats, a problem which is exacerbated by the fact that both species often share roosts. Both whiskered and Brandt's bats have been found to show little or no difference in humidity and temperature requirements during hibernation, and the flight morphology of both species is remarkably similar (Jones, 1991).

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Emergence and Flight Pattern

• Emerges in the early evening.
• Flight is rapid and agile. Fast turns can be made in the open.

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Foraging Behaviour

Marked in blue on the diagram above is a typical foraging path of Brandt's bats (based on Russ, 1999).

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Echolocation Calls

To listen to the call of the Brandt's bat click here

Size of sound file: 18.4 KB

Average values for a Brandt's bat echolocation call, as given by Vaughan et al. (1997), are listed below:

Interpulse interval: 86.2 ms

Call duration: 4.7 ms

Minimum frequency: 41.0kHz

Maximum frequency: 64.4kHz

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 45 kHz.

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Status and Protection

•  The pre-breeding population was estimated at 30,000 in 1995 (22,500 in England , 500 in Scotland , 7000 in Wales ) (Harris et al., 1995).

•  Brandt's bats are at low risk of extinction worldwide (IUCN status, 2001).

•  Bat boxes should be put up in suitable habitats to conserve existing populations.

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