Bats

Six species
The pipistrelle, the noctule, Daubenton's bat, Natterer's bat, the brown long-eared bat and the serotine bat are all found in Greater London. All European bats feed on insects and during winter when there are few active insects so bats cope by hibernating. 

Pressures
The decline in bat populations is linked to a loss of roost sites, chemical treatment of roof timers which are toxic to bats, pesticide use depleting their food source, and a dramatic loss of feeding sites. It is illegal to harm bats or disturb their roost sites. If you find an injured bat, or think that you have a roost in your house, call the Bat Helpline on 0845 1300 228. 

Bat detector
Bats use echolocation to find their way around and hunt in the dark. They emit a high frequency sound which usually can't be heard by people. Echolocation works similarly to sonar. Bats make calls as they fly, and listen to the returning echoes to build up a map of their surroundings. The bat can tell how far something is by how long it takes the sounds to return to them. These calls can be heard by using a device called a bat detector. Individual bat species echolocate within specific frequency ranges that suit their environment and prey types. This means that we can identify many bats simply by listening to their calls with bat detectors. 

Where
They can be found in grassland, farm land and near waterways and ponds. Bats are also becoming more reliant on urban habitats, where they roost in buildings and forage in nearby wooded parks and gardens. Different species prefer different habitat types and some bats will journey further out to seek the habitat they prefer. Tree habitats are important and support nearly all species of bat. They use trees for roosting sites where they can give birth to their young in a protected and sheltered environment and in winter they can safely hibernate in deep crevices. Tree habitats with their associated shrubbery attract a wide variety of insects which bats prey on and they also utilise trees and hedgerows as navigational landmarks for their nocturnal flight path. The edges of woodland and hedgerows are linear features which create a corridor for bats to commute from one area of countryside to another such as from their roost site to new foraging grounds. Waterways and ponds not only provide bats with the water they need to rehydrate but also attract midges and other flying insects which congregate in their thousands and provide a ready feast for bats. 

When
Bats are active at night and you are most likely to see them at dusk on warm summer evenings. They hibernate in the winter time so if you do find a hibernating bat do not disturb it.