Go batty over bats

Fascinating creatures

Bats are fascinating creatures. They are the only mammal capable of controlled flight, and they ‘see’ in the dark using echolocation – a highly sophisticated form of sonar that allows them to fly at speed, avoid obstacles and catch insects in mid-air. However, contrary to popular belief, they are not blind.

Many species of bats often roost in buildings, particularly in loft spaces or under eaves. However, they make use of existing spaces and cause no damage to the property. Bats and their roosts are protected by law, and must not be disturbed or harmed.

Kate Barlow, the Bat Conservation Trust’s National Bat Monitoring Programme Development Manager says: “Bats are unique - they are the only true flying mammal - but sadly they face many threats from loss of habitat, destruction of roosts and changing land use.“

A decline in numbers

Bats have been declining in numbers since the 1950s for various reasons, all related to human activity. An increase in light pollution has had serious implications for bats, which, being nocturnal, are adapted to low light conditions. A lack of plant diversity in our gardens and farmlands is bad news for insects, which are the food source for all UK bat species. Buildings now tend to be better sealed, with fewer roosting spaces, while hollow trees, another place bats make their homes, tend to be cleared away much faster.

However, steps are being taken to deal with some of the threats to the bat population. From the 1950s until the 1970s, a huge problem was the treatment of timber with chemicals designed to prevent woodworm, but lethal to bats. These chemicals have now been banned. In addition, water quality is now improving – declining water quality had meant fewer insects for bats to feed on. And canals are also playing their part in helping bats.

Bats and canals

One of the key problems facing bats is habitat fragmentation. Modern agriculture has meant a loss of hedgerows, woods and parkland. Areas of bat habitat that used to be connected are now cut off from each other and, to travel between them, bats must pass through areas that offer little in the way of food. This means that canals are very important, providing essential green corridors that are rich in insect life, allowing bats to travel around the country more easily. Mark Robinson, British Waterways National Ecology Manager, says: “For bats, canals are a cross between Tesco and the M1.”

Kate Barlow says: “Waterways are vital for bats. Rivers and canals connect habitats and bats use them as safe flight lines to commute along. Waterways also provide bats with rich hunting grounds thanks to the many insects found there. The Daubenton’s bat is even known as the water bat as it can be seen at dusk skimming insects from the surface of the water with its hairy feet!

"Each year, the National Bat Monitoring Programme runs a Waterways Survey, which helps us find out about the health of bat populations and the landscape. In August, volunteers armed with bat detectors can be seen recording Daubenton’s bats flying along a stretch of water.”

The work that British Waterways does to help maintain the canals as diverse wildlife habitats is very important for bats. For example, favouring soft bank protection where practical provides a breeding ground for aquatic insects, an important food source for bats.

Creating roosting spaces

British Waterways also takes more direct steps to help bats, by protecting their roosting sites in its heritage structures. Many tunnels, aqueducts, bridges and culverts have had bat bricks (bricks with holes for bats) added to them, or roosting chambers built in during renovation. While renovating the Pontcysyllte Aqueduct, British Waterways worked closely with the Countryside Council for Wales to ensure that the structure’s many bat roosts remained unaltered.

The restoration project at Osberton Turnover Bridge also involved the creation of bat roosting spaces. In the case of Osberton Turnover Bridge, bats had been roosting in holes in the bridge, which it was not possible to retain during maintenance. To compensate, a new roosting chamber and bat bricks were included in the renovated structure.

To record your sightings of bats and other waterways wildlife, take part in British Waterways Wildlife Survey 2011. Now also available via your mobile at www.waterscape.com/ws.

Last updated: 26/04/2011