A full version of this article appears in the magazine.

 

Bechstein's bats are one of the UK’s rarest native mammals. Present in low numbers from Kent to Cornwall and as far north as Shropshire, they are absent from Scotland and Northern Ireland and have seldom been recorded in Wales.

 

Evidence from the fossil record suggests this woodland specialist was probably more common 2,000 years ago, before Britain's woodlands were cleared for agriculture. Although a few individuals are found in underground sites during hibernation, most roost in trees all year round. Their favoured roost sites are old woodpeckers' holes. These are used as maternity roosts and also by solitary males.

 

The elusive bat

Bechstein's bats are medium-sized with long, broad ears that help when feeding on ‘noisy’ arthropods including moths, crickets, harvestmen, earwigs, ground beetles and spiders; the bats often pick these insects off vegetation. They emerge from roosting sites approximately 25-30 minutes after sunset, and set off in pursuit of their prey. They fly relatively low when hunting, selectively picking prey from the ground or within the canopy.

 

The mating season, as with all bat species within the UK, occurs between autumn and spring; nursery roosts are occupied from the end of April, and births occur towards the end of June. One young is usually produced, which is able to fly by mid August.

 

This is an extremely elusive species, rarely found outside the cover of a woodland canopy or hedgerow. They emit very quiet echolocation calls, making them difficult to detect. Their ability to recognise fine detail makes them good at evading capture from licensed surveyors using nets.

 

Conservation conundrum

So how does one, faced with the rarity of this species and the difficulties associated with finding out about it, address the threats which it may be facing, and may be threatening its last pieces of habitat?

 

Technology has come to the rescue. Recent developments in bio-acoustics led David Hill and Frank Greenaway from the University of Sussex to conduct field experiments using a bat call synthesizer. The synthesizer, or Autobat, is an acoustic lure which replicates social calls from Bechstein’s bats. It has proved successful, greatly increasing our knowledge of the distribution of Bechstein’s bats in southern England.

 

This work has shown that conducting rapid systematic surveys for Bechstein’s bat is feasible. So what about Wales? Are there individuals, populations even, of this rare native mammal that we may not be aware of? Well, probably yes, and thanks to a successful funding application, we are now in a position to investigate this possibility.

 

The Bechstein’s Bat Survey Project

Groundwork began in September 2007. The first task was to identify suitable woodland sites to survey and approach landowners for access permission.

 

The second, hands-on part of the project will of course be the most interesting part for our eager volunteers. BCT is recruiting volunteers with bat handling expertise, to undertake the survey work during this phase. They will then be trained, beginning the survey in April 2008, initially focussing on Carmarthenshire and Glamorgan and using the Autobat.

 

We hope to be able to report our early findings later this year. This should reveal where our Bechstein’s bats are and allow us to provide targeted habitat management advice for land managers.

 

This is truly an exciting time to be involved with bat conservation and I do feel privileged to play some part. Rarely do we get an opportunity to be up close and personal with such a rare and threatened species as the Bechstein’s bat.

 

Richard Dodd is Welsh Bat Officer at the Bat Conservation Trust, the only UK organisation solely devoted to the conservation of bats and their habitats.