Species Biodiversity Action Plans (Summaries)

Species Biodiversity Action Plan -Pipistrelle bat

Common name: Pipistrelle bat
Scientific name: Pipistrellus pipistrellus

Description

The pipistrelle is Britains smallest bat (forearm: 30-35 mm; head and body: 40 mm; wingspan: 200 mm; weight: 4-8 g), with fur that varies from red-brown to dark brown, and that is usually lighter on the animals under-side.

Its ears are short and bluntly rounded, with a tragus that is longer than it is broad and also bluntly rounded. There is also a post-calcarial lobe present.

Species_bat.jpg (5410 bytes)
Picture from Wardhaugh, 1995.

In fact it has recently been recognised that there are two distinct species of pipistrelle bats. The 'bandit pipistrelle' has a black face and dark brown fur, whilst the 'brown pipistrelle' has a brown face and more chestnut brown fur; the two also differ in the frequency at which they echo-locate.

The pipistrelles are active from march to October/November, and will also feed on winter nights if the temperature exceeds 8 oC. Their diet consists of small insects (up to 3000 in a night) eaten in flight, and as a result they have a distinctive, fast, jerky flight pattern as they pursue their prey.

During the summer months they prefer to roost in buildings (even relatively new buildings), particularly in confined spaces around the edge of buildings (behind barge boards, loose tiles etc), since they require an entrance that may be as small as half an inch wide. In winter however, they are much less frequently sited, since they will roost in small groups in crevices in buildings or in trees, and are therefore difficult to find; only rarely will they roost in caves or tunnels. If however, extreme cold forces them to change roost, they can appear in houses, or in very exposed locations (such as clinging to a wall).

Mating generally occurs in the autumn or occasionally in the spring, at established mating roosts. maternity roosts consisting almost exclusively of females are then formed and occupied between May and August/September, with one (or occasionally two young being born sometime between early June and mid-July.

Legal Protection

  • Pipistrelles appear in Appendix III of the Berne Convention (Convention on the Conservation of European Wildlife and Natural Habitats). This requires that they be protected from exploitation (indiscriminate mass killing, trading and any means capable of causing local disappearance or serious disturbance to the species) and managed to keep them out of danger.
  • They are also appear in Appendix II of the Bonn Convention on the Conservation of Migratory Species of Wild Animals, under which signatories are encouraged to draw up agreements to restore/maintain species' conservation status through management and other appropriate measures.
  • Pipistrelles are also protected under Annex IV of the European Communities Council Directive on the Conservation of Natural Habitats and Wild Fauna and Flora. This covers species of community interest that are in need of strict protection. Damage or destruction of breeding sites or resting places is prohibited, and all life stages are protected against deliberate capture, killing or disturbance in the wild; and keeping, transport, sale/exchange and offering for sale/exchange of specimens.
  • Under domestic legislation, pipistrelles are covered by the Wildlife and Countryside Act 1981 (as amended). Under Schedule 5 the deliberate killing, injuring, taking, possessing, disturbing and selling (including parts and derivatives) as well as damaging, destroying or obstructing any structure or place of refuge etc are prohibited. Under Schedule 6, certain methods of killing or taking animals are specifically prohibited, and even humane trapping for research requires a licence.

Current Status

Although the pipistrelle is still the most abundant and widespread bat species in the UK (being present throughout with the exception of Shetland, Orkney and some of the Western Isles), the population is thought to have undergone a marked decline in numbers over the last 100 years. Indeed estimates from the National Bat Colony Survey suggest that numbers may have reduced by 70% between 1978 and 1993. The current population is thought to be around 2,000,000 individuals, although accurate figures are difficult to obtain, particularly since there are now two separate species to consider.

Threats and Issues

  • Reduction in insect prey abundance, due to high intensity farming practice and inappropriate riparian management.
  • Loss of insect-rich feeding habitats and flyways, due to loss of wetlands, hedgerows and other suitable prey habitats.
  • Loss of winter roosting sites in buildings and old trees.
  • Disturbance and destruction of roosts, including the loss of maternity roosts due to the use of toxic timber treatment chemicals.

Objectives (as pertinent to agriculture)

The national species action plan specifies the following two objectives:

  • To maintain existing populations and range of pipistrelles.
  • To restore populations to pre-1970 numbers.

Conservation Advice

  • The less toxic chemicals now available should be used to preserve timbers in buildings, due to the extent to which pipistrelles rely on buildings for roosting sites.
  • Great care should be taken when renovating buildings to ensure that roosts are not adversely effected (destroyed or access blocked).
  • Dead and dying trees should be left wherever possible.
  • Habitat adjacent to roosts should be sympathetically managed to encourage insect (food) populations. Particular thought should be given to the inclusion of hedgerows and wetlands.

References and Further Information

Bat Conservation Trust. (2000). Pipistrelle: Pipistrellus pipistrellus & P. pygmaeus.[Internet], London, Bat Conservation Trust. Available from: http://www.bats.org.uk/batinfo/pipis.htm. [Accessed 20 January 2001].

Betts, C.J. (1998). Checklist of Protected British Species. Christopher Betts Environmental Biology, Worcester, UK.

Mitchell-Jones, A.J. (1994). The Bats of Britain and Ireland . The Vincent Wildlife Trust, London.

Stebbings, R.E. (1988). Conservation of European Bats. Christopher Helm, London.

Stebbings, R.E. and Griffith, F. (1986). Distribution and Status of Bats in Europe. Institute of Terrestrial Ecology, Huntingdon, UK.

UK Steering Group. (1995). Biodiversity: The UK Steering Group Report, Volume 2: Action Plans. HMSO, London.

Wardhaugh, A.A. (1995). Bats of the British Isles. Shire Natural History, Princes Risborough, UK.

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