Identification – Our only flying mammal, there are 16 species of bat in Britain and all are nocturnal. They are found in a wide range of habitats but favour woodland, river corridors and water bodies, and their roosts can be in almost any type of building, no matter how old or new. All species of bat have legal protection preventing any form of disturbance to their roosting sites, whether they are occupied or not, and it is illegal to harm or kill a bat.

General Ecology – Their annual life cycle involves winter hibernation in special roosts, and summer breeding, for which different roosts are used. For  detailed information about bats, see the Bat Conservation Trust website, and the Essex Bat Group website (which includes some videos of bats).

Surveying for Bats – The least intrusive survey method is to use a bat detector, which translates their ultrasonic calls to frequencies that can be heard by the human ear. Many models of bat detector are available, but an inexpensive model is made by Magenta Electronics. Surveys cannot be carried out in the hibernation season. All other survey methods can only be carried out under license from Natural England and have to be conducted by a qualified person.

Essex Biodiversity Project work - In the winter of 2005, the Essex Biodiversity Project provided financial support and technical expertise to the River Colne Countryside Project in their initiative to build bat hibernacula. (Hibernacula are suitable places in which bats can hibernate during the winter.)

We converted two World War 2 pill boxes into hibernacula in the River Colne valley. This involved adding metal doors to prevent any intrusion by people or other animals and to help keep the temperature constant and the installation of special 'bat bricks', designed with bat-friendly holes.

We have organised the building and distribution of bat boxes to appropriate sites around the county. We have also provided guidance to the landowners on the siting of the boxes.

Further information

See the Essex Bat Group webite