Pipistrelle Bats Pipistrellus spp.

Bats are the world's only true flying mammals and one of the most diverse mammal groups on Earth. There are 16 recognised species of bats breeding in the UK. The Pipistrelles are Britain's smallest bats. They have a head and body length of about 4 cm and a wingspan of 20 cm. They weigh only 5g, which is less than a two pence piece. Pipistrelles can vary in colour but are usually medium to dark brown on the back and a little paler underneath. There are two distinct forms of Pipistrelle bats, the Common Pipistrelle (Pipistrellus pipistrellus) and the Soprano Pipistrelle (Pipistrellus pygmaeus).

Pipistrelles are associated with most habitats, particularly woodland edge, hedgerows and gardens, they are often seen around water. Pipistrelles are the most common bats in towns and suburbs. Pipistrelles catch their food in flight and usually eat while on the wing. They mainly eat flies such as Midges and Caddis flies. They will also take Mosquitoes, Gnats, Mayflies, Lacewings and occasionally small Moths.

During the summer, female Pipistrelles group together to form large 'maternity colonies' to have their young. They will use buildings, trees and bat boxes. They spend the day in roosts, then come out at dusk to feed. Pipistrelles generally choose undisturbed, cool places with an even temperature in which to hibernate throughout the winter.

Current Status

Pipistrelles are found throughout the UK. They are also abundant and widespread in the rest of Europe. Although they are the most common British species, Pipistrelles are thought to have undergone a significant decline in numbers. Estimates suggest a population decline of approximately 70% between 1978 and 1993. Pipistrelles were therefore included on the UK Biodiversity Steering Group 'Short List of Globally Threatened/Declining Species'. There are problems with estimating population trends due to the recent discovery that what was thought to be one species is actually two, the Common Pipistrelle and the Soprano Pipistrelle.

The Common Pipistrelle is widely distributed throughout the area surrounding Hull, and there are several recorded roost sites within the city. There are no records for the Soprano Pipistrelle in Hull, it is thought to be a more rural species, whereas the Common Pipistrelle is better adapted for the urban environment.

Current Factors Affecting Pipistrelles

• The increased use of insecticides has reduced the amount of insect prey available to Pipistrelles during their active season.
  
  
• Loss and fragmentation of insect-rich feeding habitats and flyways, for example woodlands, woodland edge, field margins, wet pasture and other suitable habitat types, may also be a factor in their decline.
  
  
• Disturbance and destruction of roosts, for example the loss of access to actual or potential sites through building alterations and loss of maternity roosts through the use of toxic chemical timber treatments.
  
  
• Widespread misunderstanding of legislation protecting bats, leading to loss or damage of many roosts when consultation procedures have not been carried out.
  
  
• Loss of winter roosts such as hollow trees and exclusion from buildings by unsympathetic roost owners.

Current Action

Legal Status

Pipistrelles are listed on Appendix III of the Bern Convention, Appendix IV of the EC Habitats Directive and Appendix II of the Bonn Convention. Bats and their roosts are also fully protected under Schedule 2 of the Conservation (Natural Habitats etc) Regulations, 1994. The Wildlife and Countryside Act (1981) gives very full protection to bats because of their special requirements for roosting. It is illegal intentionally to kill, injure or handle any bat. It is also illegal intentionally to damage, destroy, or obstruct access to any place that a bat uses for shelter or protection, or to disturb a bat while it is occupying such a place. Pipistrelles return to the same places year after year and so roosts are protected even if there aren't bats there all the time. English Nature must be informed before anything is done that would affect Pipistrelles or their roosts.

Management, Research and Guidance

The UK Biodiversity Steering Group has produced a Species Action Plan for Pipistrelles. The target of the plan is to maintain and enhance the existing population and range of these bats. The plan also aims to restore populations to pre-1970 numbers. The Bat Conservation Trust (BCT) is the national lead organisation for the Pipistrelles and other priority species of bat. They have produced an action plan for the conservation of all bat species in the UK and have a national network of local groups.

The Joint Nature Conservation Committee (JNCC) recently commissioned a National Bat Habitat Survey, which provided information on habitat preference and distribution.

The National Bat Colony Survey has monitored many Pipistrelle roosts since 1978 on the basis of annual summer roost counts. The National Bat Monitoring Programme (NBMP) was started in 1995, with the overall goal of developing an effective monitoring strategy for resident species of bat in the UK. Only one roost site within Hull has been monitored for the NBMP, data from this site suggests that the colony is relatively small (less than 50 bats) but stable.

A large amount of research is under way to investigate reproductive physiology, mating strategies, field activity, and morphology and ecology of the two Pipistrelle species by investigation of echolocation calls and genetic material.

English Nature provides advice to householders, builders and the general public in any cases where bats or roosts in a house may be harmed or endangered. English Nature also controls licensing for handling or disturbing bats for research, education and nature conservation purposes only. The Department for Environment, Food and Rural Affairs (DEFRA) controls licensing for impacts upon bats in connection with development and other operations, unless it is in a house.

The East Yorkshire Bat Group (EYBG) carries out surveys of where bats roost, feed and hibernate. They care for sick or injured bats, erect bat boxes to give safe additional roosts and offer advice and information to householders sharing their homes with bats. The group also gives talks and lead bat walks where you can see and hear wild bats.

Action Plan Aims

1. To determine the number and distribution of Pipistrelle roosts in Hull.
   
   
2. To encourage favourable management of land near known roost sites.
   
   
3. To ensure land and property owners are aware of the presence of Pipistrelles.
   
   
4. To raise the awareness of property and landowners of the endangered and protected status of pipistrelle bats and their roosts.
   
   
5. To provide advice on conservation management of roosts and foraging habitats.
   
   
6. To raise public awareness of the status of Pipistrelle bats through education, public events and providing information.

What We Are Going to Do

What We Can All Do

• By gardening in a wildlife-friendly way you will encourage a variety of animal visitors and hopefully bats will be among them. By growing night-scented flowers you can attract moths and other night-flying insects that are of particular importance for bats.
  
  
• Put up a bat box, they are similar to tree holes and are an extra option for bats searching for a roost site.
  
  
• If you have a Pipistrelle maternity colony roosting in your house consider carrying out colony monitoring for the National Bat Monitoring Programme. This survey is appropriate for volunteers with little or no previous experience.
  
  
• If you find a grounded or injured bat contact either your nearest Veterinary practice, the RSPCA or the East Yorkshire Bat Group Helpline.
  
  
• Let the Biodiversity Partnership know if you are lucky enough to have bats roosting in your house.
   

Links With Other Action Plans

Management of The Built Environment will be very important for Pipistrelles. Other habitats including Grassland, Trees, Scrub and Hedgerows, Fresh Water Habitats, Gardens and Allotments and Parks, Golf Courses and Cemeteries will also be important because they provide feeding habitat for Pipistrelles.

References

Corbet, G.B., Harris, S. (1991) The Handbook of British Mammals. (3rd edition). Blackwell, Oxford.

English Nature (1993) Bats in Roofs: A Guide for Surveyors. English Nature, Peterborough.

Entwistle, A.C., Harris, S., Hutson, A.M., Racey, P.A., Walsh, A., Gibson, S.D., Hepburn, I., Johnston, J. (2001) Habitat Management for Bats. JNCC, Peterborough.

Harris, S., Morris, P., Wray, S. Yalden, D. (1995) A Review of British Mammals: Population Estimates and Conservation Status of British Mammals other than Cetaceans. Joint Nature Conservation Committee, Peterborough.

Mitchell-Jones, T. (2000) Focus on Bats. English Nature, Peterborough.

Bat Conservation Trust (2002) Garden for bats. (Retrieved March 2002 from http://www.bats.org.uk)