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Press release

  • 15 February 2008

New technique allows first nationwide survey for rare woodland bat

David Hill had developed the Sussex Autobat, which is being used to survey the rare Bechsteins Bat.

David Hill had developed the Sussex Autobat, which is being used to survey the rare Bechstein's Bat.

The rare Bechsteins Bat.

One of the UK's rarest mammals - Bechstein's bat - will be surveyed and monitored under a new three-year project using technology developed by the University of Sussex.

Bechstein's Bat Project, launched this month (February) by The Bat Conservation Trust (BCT), aims to map the national distribution of this rare and elusive bat. The project will use an ultrasound synthesizer, called the 'Sussex Autobat', which simulates social calls to lure these tree-dwelling bats into a harmless harp trap.

The method was developed by leading bat experts Dr David Hill, lecturer in ecology and conservation at the University of Sussex, with Frank Greenaway, a freelance bat consultant. They have already used it to map the distribution of the species across the whole of Sussex. It uses a model of ideal habitat to predict which woods female breeding roosts are likely to occur in and then these woods are surveyed using the Autobat.

Dr Hill said: "A rough estimate has put the British population of Bechstein's bat at just 1,500 - compared with estimates of around 1.3 million for the Common Pipistrelle. But the truth is, for Bechstein's, we just don't know how many there are. They are extremely difficult to observe in their foraging and roosting habitats, which are usually in dense woodland, and they can be very hard to capture. With our technique they can be captured much more frequently and safely."

Under the new project, BCT is aiming to undertake the first survey for Bechstein's bats across their entire UK range in England and Wales. The surveys will be done by volunteers from local bat groups who will be trained in using these new methods.

Helen Miller, Bechstein's Bat Project Officer at BCT, said: "The project will give us detailed data for the Bechstein's bat for the first time, which will make an enormous difference by informing our conservation work for this species. It will also leave a legacy of trained, enthusiastic volunteers who can help keep track of the Bechstein's bat in the long term to help ensure their survival."

A third of the UK's mammal species are bats, however, populations of all 17 of our native species have declined dramatically since 1900. Development, modern agriculture, pesticides and public misconceptions have all contributed to their decline. Seven species of bats, including the Bechstein's bat, have been identified by the Government as priority species under its Biodiversity Action Plans scheme, which aims to halt biodiversity loss by 2010.

Amy Coyte, chief executive of BCT, said "This project will directly inform the government's UK Biodiversity Action Plans for the Bechstein's bat, substantially improving knowledge of the bat's habitat requirements and enabling landowners to manage woodlands for this rare species."

"The more knowledge we have about Bechstein's bats, the better we will be able to conserve them and ensure they are around for future generations to enjoy."

Notes for editors

Bechstein's Bat Facts

  • The most recent population estimates are of around 1500 individuals with overall population trends unknown in the UK.
  • The first confirmed breeding colonies were found in Sussex and Dorset in 1998.
  • It feeds on invertebrates including spiders and resting day-flying insects which are picked from branches and leaves.
  • Remains in cave deposits suggest that around 3,000 years ago Bechstein's bat was much more common in the UK. Widespread deforestation probably caused their decline.
  • Head and Body length: 4.3cm-5.3cm, wingspan 25cm-30cm
  • Found mainly in Southern England


University of Sussex Press Office:  Jacqui Bealing and Maggie Clune, 01273 678888,



Bat Conservation Trust contact: Jaime Eastham 0207 501 3635



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