A RARE bat has been found on the RSPB's reserve at Radipole Lake in Weymouth.

The Nathusius's Pipistrelle, one of the smallest and rarest bats nationwide, was discovered during a survey undertaken by volunteers from the Dorset Bat Group.

The group, supported by the Bat Conservation Trust, has been working with the RSPB to look at how bats are using the site, particularly a number of newly-restored ditches.

The survey has also shown that the ditches are very popular with at least five or six other species of bats.

Radipole and Lodmoor reserves manager Nick Tomlinson said: "This is a really exciting find. Our bat walks are very popular and we usually manage to see quite a few different species, but we have never managed to find one of these little bats. This is a new record for the reserve and only the third sighting in Dorset so it is really great news.

"The ditches this bat is using were restored last winter, the first such work to be undertaken on the reserve for more than 20 years and the first step in a larger plan to improve the reserve for wildlife.

"The RSPB is working very hard to improve biodiversity across all its sites. That means we are making sure that our nature reserves are rich in all kinds of wildlife, not just birds, but plants and insects and, of course, bats, as well as other mammals.

"A good, healthy population of birds is a clear indicator that things are going well, but that is only part of the story.

"To have the very best everything has to thrive and that is what we are aiming for."

Further survey work since the original finding has shown that the Nathusius' is, along with several other species, using the site regularly.

Nick said: "The Nathusius's Pipistrelle has a strong association with water, so the fact that it has chosen to use ditches that did not exist until this year might be seen as a seal of approval for the work, especially as there seems to be bat activity over the ditches almost all night.

"We are very pleased and it will be really interesting to see what else the bat group finds as the survey progresses."