THE SECRET LIVES OF BATS

17/08/2007 00:00:00 The National Trust reveals more unusual stories about bats

May 2007. Bats are one of the most enigmatic creatures found in the UK and probably one of the most misunderstood. Of the 17 species resident and breeding in the UK and Ireland, you can find all on National Trust land. At Holnicote Estate in Devon, you can find no less than 15 of them. The smallest bat found in the UK is the common pipistrelle, which weighs in at under 5 grams (a 2p piece), yet can eat 3000 flies in a single night. The largest is the noctule, which has a 35 cm wingspan and can fly up to 30mph to catch moths and beetles to eat.

Dr. David Bullock, Head of Nature Conservation, says, ‘We have a special responsibility for bats at the National Trust. Almost all of our properties play some part in the lives of these wonderful creatures. Historic buildings and ancient woodland provide important roost and hibernation sites. Farmland, parks and water are vital for feeding. Even air raid shelters, grottos and icehouses have become homes to bats.

‘Bats are seen as an indication of how healthy the environment is and in recent years they have been declining across Europe. Increased development, loss of habitat and pollution has all had a part to play. On top of this, changes to the way we construct houses mean huge roof voids are a thing of the past and only found in older buildings. These are the kind of spaces that bats love and need. At the National Trust we have many large roof voids making us the perfect landlord for bats. Tracking the elusive Barbastelle
A new project will start this summer at Ickworth in Suffolk tracking the eight species of bat resident in the house and grounds. Of particular interest is the Barbastelle, a rare bat that spends its life in woodland making it hard to track. There are only a handful of breeding sites known for this bat and the National Trust hope the project will add Ickworth to the current list. Central to the success of the project is fitting Barbastelle bats with tiny radio transmitters. This means that the Trust can track the bats at anytime of day and night.

Another new project for this summer is a huge bat survey in Norfolk. With help from the public the Trust wants to build up a sound picture of the night sky. People can go out in their cars, open the windows and using a bat detector start recording sounds of the night. Again the focus of the project will be the Barbastelle whose only known breeding colony in the county is near Cromer.

Long haul flying
At Wimpole in Cambridgeshire a recent radio tracking exercise uncovered some very interesting commuting habits. One female Barbastelle travelled miles to the edge of Cambridge to feast on her favourite food of micro moths. Then she would return to the roost to suckle her pup before heading off for a second time to Cambridge to fill herself up before daybreak.

Wimpole has everything a bat needs; mature trees, vast areas of parkland, woodland, lakes, farmland and old buildings. The cellars underneath the hall are an important roost site and even the void under the grand staircase up to the entrance of this stately Georgian mansion has been colonised by bats. Living side by side
At Brockhampton in Herefordshire the bats really do make themselves at home. Each night staff cover up the precious furniture with special bat proof covers. These have proved so successful that new covers have been made to protect the paintings, guns and other wall-mounted treasures at risk from having bats live in close proximity.

Chastleton House in Oxfordshire was once home to a roost of horseshoe bats. One former resident remembers the bats leaving their roost in the roof, flying down the stairs and exiting the house on the ground floor. The house and estate is still an important place for bats, however, they have found an alternative exit and no longer use the stairs as their thoroughfare.

At Avebury in Wiltshire there is a colony of Natterer’s bats living in the Manor Barn. There is a large umbrella strategically covering the reception area to protect unsuspecting visitors and staff from unwelcome bat droppings.

Bat Creche
During the summer months the attics of Brockhampton in Wales are turned into a maternity roost. Mothers move in to rear that year’s young and create a temporary bat nursery. At Mottisfont in Hampshire, the woods are home to one of only a handful of known Barbastelle maternity roosts.

Bats uncovered
At the same time each year a swarm of Serotine bats turn up at Calke Abbey in Derbyshire to feast on Cockchafers. As quickly as they arrive, they disappear again and staff have never found their roost.

In the stable block at Dunster Castle in Somerset visitors can get a rare look at the secret life of bats through a CCTV camera installed in their roost. Last year the camera even captured the rare sight of a lesser horseshoe bat giving birth. A helping hand
Sometimes the Trust needs be a bit more pioneering when working with bats. Special bat-shaped plaques indicate crevices in stonework where bats roost so that overzealous builders do not repoint them. At Greys Court in Oxfordshire scaffolding netting was blocking off the resident bats route to their roosts. The answer was to cut large holes in the netting, giving the bats their usual access. And at Upton House in Warwickshire special bat tiles were installed in the roof to the new shop when a roost was found.

Unusual homes
Bats like to roost where it is warm. However, they do not always pick ideal locations for their homes. At High Wray Basecamp in Cumbria the resident bats had taken to roosting next to the stove and were in danger of being cooked. A local enthusiast built a bat box to provide a more comfortable and less risky roost. So popular was this new box that last summer it contained a breeding roost of 199 Soprano Pipistrelles.

You can also find bats in cellars, sewers, bomb shelters, icehouses and temples on National Trust land.

Bat walks
Throughout the summer there are bat walks happening up and down the country at National Trust properties. For further details visit the events pages of the website at www.nationaltrust.org.uk/events.