Barbastelle bat in Dendles Wood (DNPA)
New light is shed on the whereabouts and habits of the elusive barbastelle bat on Dartmoor, thanks to pioneering research.
Barbastelles are classified as vulnerable, in the species at risk list
The use of insecticides has limited the supply of their favourite foods - small insects
Their habitat tends to be wooded river valleys and mountain regions
Their vital statistics are: Body length 4.5-5.8cm, Wingspan 26-29cm, Weight 6-13g
The maximum recorded age for a barbastelle bat is 23 years.
The barbastelle bat is one of Britain's rarest, most elusive mammals, and catching a glimpse of them needs a certain amount of ingenuity.
So when a research project into their whereabouts and habits on Dartmoor was launched, some clever trickery was used to track the night-time creatures.
University PhD student Matt Zeale spent over 120 nights, from late May to September 2007, trapping and tracking the little bats in Dartmoor's wooded river valleys.
And he used new technology to locate them - in the form of acoustic lures which playback the bats' calls and attract them into nets.
That enables the research team to keep tabs on the bats during their nightly forays.
During his research, Matt discovered a thriving new breeding colony of barbastelle bats on Woodland Trust land in the Bovey Valley.
Dendles Wood is home to barbastelles (DNPA)
He also confirmed the presence of two barbastelle breeding colonies in the Dart Valley and in Dendles Wood National Nature Reserve in the south of the Dartmoor National Park.
The research has shown that Dartmoor barbastelles seem to travel up to 4km to their feeding grounds, where they prey on moths over mature hedges.
However, on occasions, the Bovey Valley bats have been tracked up to 20km towards Teignmouth.
The Dendles Wood bats foraged well beyond Ivybridge towards Plympton. Elsewhere, the bats are known to travel long distances to their preferred foraging grounds to feed over wetlands as well as hedgerows.
Another interesting finding is that the Dartmoor bats seem to strictly divide their feeding areas between individual bats, which may explain why they are so thin on the ground.
Dartmoor National Park Authority ecologist, Miriam Glendell, said: "The research will continue next year and it is hoped that once we know the areas used by all the colonies, practical conservation action can follow to secure the bat's future within the river valleys.
"As a top predator, barbastelles are at the head of the food chain and depend on a well connected healthy landscape. So conservation measures to benefit the barbastelle could potentially benefit a whole range of other species and habitats."
Until recently, it has been difficult to research the bats because they roost under peeling bark, and in holes in damaged and dead trees. Their choice of 'home' places them at risk, because it is these sort of areas which tend to be 'tidied' up.
There are only about 16 known breeding colonies in England and Wales, with a total population of 5,000. However, the exact status and distribution is unknown so the research on Dartmoor provides important information into the species' ecology and distribution.
The £25,000 research project on Dartmoor is a partnership between the park authority, the Woodland Trust and the National Trust, with funding from the SITA Trust.
last updated: 21/02/2008 at 15:55