There are 17 species of bat in the UK, several of which can be found across London. Bats have been sighted in all the London boroughs and the pipistrelle is common in the inner London boroughs.
Appearance and behaviour All British bats are relatively small - the pipistrelle is just five centimetres long, with a wing span of 20 centimetres and a weight of four grams. One of the largest and most widespread is the noctule, which can reach a length of eight centimetres, and is often mistaken for a swift as it flies high soon after sunset. All European bats feed on insects, from tiny gnats to large beetles. During winter there are few active insects so bats cope with this seasonal lack of food by hibernating.
Conservation issues Bat numbers are in decline. This 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. For these reasons all bats are protected by law under the Wildlife & Countryside Act 1981 (as amended). 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.
Wild facts Some bats have swapped traditional roosting sites for small crevices in buildings - behind weather boarding or between roofing felt and tiles. It's estimated that in one night a pipistrelle can eat up to 3,500 insects. Bat droppings make very good organic fertiliser (if you can collect enough!). There are many myths about bats. The saying "as blind as a bat" is wrong as bats can see perfectly well, although not in colour. Bats don't get tangled in long hair when flying as they have excellent 'night vision' using echo-location - emitting a high frequency sound which usually can't be heard by people. Out of almost 1000 species of bat around the world only three drink blood from large animals and they all live in South or Central America.
Where to see them If you want to see bats then go for a stroll at dusk around your local park or nature reserve. Also look out for them near trees (particularly brown long-eared bats) or water, or maybe under a street light, picking off all the insects attracted to it.
In your patch Find out about bats spotted in your area with the fantastic WIMBY tool, run by GiGL – Greenspace Information for Greater London.
Spotted Have you seen any bats in London? Let us know! Register with GiGL and tell us about the species you’ve spotted in the capital.
Bat project Sydenham Hill Wood is the home of the Woodland Bat Roost Project, funded by the SITA Trust with additional help and money from Southwark and Lewisham Councils. This project aims to improve the wood for bats, where at least five species of bat have been spotted. If you'd like to find out more about the bat project and how you can help, contact Chantal Brown - cbrown@wildlondon.org.uk