Bats
Research on the size of bat populations in the UK is still a fairly recent development but it is thought that numbers of common pipistrelles declined by around a half between roughly 1970 and 1990. Other bat species are likely to have followed a similar trend. Following an increase in legal protection in the 1980s and 1990s, numbers of some bat species have started to creep up again.
All British bats feed only on insects and the occasional spider. Most species feed around trees or hedgerows with some species requiring mature woodland, but others make do with scatterings of trees in parks or gardens. When bats are flying to their feeding areas they usually follow natural features in the landscape such as hedgerows, tree lines or watercourses. Therefore it is important for them that this network is retained.
Pipistrelle bats seem to prefer modern houses and will move roost quite frequently but most other bat species have traditional roosts in old buildings, bridges or trees that they use year after year. Protecting traditional roosts is vitally important for the survival of local populations of bats hence bat roosts as well as bats themselves are protected by law.
Eight of the 16 species of bat that breed in Britain are found in the Tees Valley. Listed very approximately from what are likely to be the commonest to the rarest in the Tees Valley these are: Common pipistrelle, Daubenton’s, brown long eared, noctule, Natterer’s, soprano pipistrelle, whiskered, Brandt’s. The Common pipistrelle probably makes up at least 90% of the total number of bats in the Tees Valley and other than Daubenton’s the other bats are likely to be quite rare locally.
