Ne Focus on Bats (4889)

Natural England works for people, places and nature to conserve and enhance biodiversity, landscapes and wildlife in rural, urban, coastal and marine areas. We conserve and enhance the natural environment for its intrinsic value, the wellbeing and enjoyment of people, and the economic prosperity it brings. Focus on bats: www.naturalengland.org.uk discovering their lifestyle © Natural England 2007 and habitats Printed on Evolution Satin, 75% recycled post-consumer waste paper, elemental chlorine free ISBN 978-1-84754-019-5 Catalogue code NE23 Written by Tony Mitchell-Jones. Designed and printed by statusdesign.co.uk Front cover image: Brown long-eared bat in flight. Stephen Dalton/NHPA. www.naturalengland.org.uk Focus on bats This leaflet is designed to answer many common questions people have about bats. If, after reading it, you’d like to learn more about bats and their conservation, get in touch with your local bat group or the Bat Conservation Trust (see Contacts, page 22). In England, all bats and their roosts are protected by law. If you wish to do anything that might disturb bats or affect their roosts you should seek advice from Natural England first. See Bats and the law, page 21. What’s special about bats? east Asia, which is little bigger than a Bats are the only true flying mammals. large bumblebee. In Britain, there are Like us, they are warm-blooded, give only 17 bat species, all of which are birth and suckle their young. They are small and eat insects. also long-lived, intelligent and have a complex social life. Although they’re In many parts of the world, including often called flying mice, they’re not Britain, bats have declined drastically closely related to mice but form a in recent years. Although we don’t special group of their own called the have much historical information Chiroptera (from the Greek words on their numbers, it’s clear that our ‘chiro’ meaning ‘hand, and ‘ptera’ bats are under threat and many meaning ‘wing’). Worldwide, there are species are now much less common over 1,000 bat species, ranging from than they were. One species, the the tropical flying foxes, with a wing- greater mouse-eared bat, is more span of almost two metres (six feet), or less extinct in Britain and several down to the hog-nosed bat of south- others are very rare. Group of young brown long-eared bats. Melvin Grey/NHPA Brown long-eared bat. F. Greenaway Brown long-eared bat. F. 2 3 Bat biology flying, bats produce a stream of high-pitched calls. By listening to the Wings echoes of these calls, they can Bats’ wings are made out of a soft, produce a highly accurate ‘sound elastic membrane of skin stretched picture’ of their surroundings. over their arms and legs. Bats have Most of these echo-location calls are the same types of bones in their arms too high pitched for us to hear, but as humans, but their hand bones are relatively inexpensive electronic bat much longer. As their arms and legs detectors are now available that can help to support the wings, bats find pick them up and turn them into it easiest to hang upside down when sounds audible to the human ear. they’re roosting. Some species wrap their wings around themselves like a Feeding cloak when they’re asleep. Worldwide, bats eat many things. Some are vegetarian, eating only Sonar fruit or even nectar; while others hunt Although bats are far from blind, fish, frogs, mice, or even other bats. their eyes aren’t much use when However, in countries with cool hunting insects in the dark. To help climates, such as Britain, bats eat them hunt, bats have developed a only insects, which they catch in highly sophisticated echo-location flight or pick off water, the ground or system that allows them to catch tiny foliage. Some bats specialise in insects and avoid obstacles, even in catching large insects such as beetles complete darkness. When they’re or moths, but others eat very small insects, such as gnats, midges and Greater horseshoe bat, one of our largest species. Stephen Dalton/NHPA mosquitoes, catching thousands of them every night. Bats gather to feed wherever there are lots of insects, so the best places to find them include areas of traditional pasture, woodland, marshes, ponds and slow-moving rivers. Hibernation There aren’t many insects around during the winter, so insectivorous animals like bats have to change their ways in the colder months. Birds Bechstein’s bat. F. Greenaway bat. F. Bechstein’s change their diet or migrate south to 4 5 about. Even on very cold nights, bats may be seen on the wing as they move to more sheltered roosts. Flying in winter uses up energy which the bats can’t easily replace. Hibernating bats should not, therefore, be disturbed as this might affect their chances of surviving into the spring. Bats have much better control over their body temperature than other hibernating animals, such as hedgehogs or dormice. Even during the summer they can conserve energy by letting their body temperature drop when they’re in their roosts. In this way, bats can sleep through periods of bad weather Whiskered bat and Natterer’s bat in hibernation. when other small animals might The bats are so cold that condensation forms on starve to death. their fur. Tony Mitchell-Jones/Natural England warmer climates, but our bats have Breeding perfected a different technique – Our bats have a unique and they hibernate. During the autumn, fascinating way of fitting their Pipistrelle bat in flight. Hugh Clark/FLPA bats put on weight and then, as the breeding cycle in with hibernation. How do bats live? weather gets colder, they let their They mate during the autumn or Lifespan body temperature drop to close to winter, but the female stores the Compared with other small Most bats form social colonies for at that of their surroundings. They also sperm alive in her body and becomes mammals such as shrews and mice, least part of the year. Female bats slow their heart rate to only a few pregnant the following spring. bats are amazingly long-lived. They gather together in maternity colonies beats per minute. This helps their fat Pregnancy lasts for six to nine weeks can live for over 25 years in the wild – for a few weeks during the summer to reserves last as long as possible. In and can vary in length depending on a remarkable feat for an animal give birth and rear their babies (a this state, bats can’t wake up quickly the weather. Usually, only one baby is weighing less than 10 grams! Part of female bat will usually only give birth to move out of danger, so they born each year. This is looked after the reason for this long life-span to a single baby each year). Once the choose undisturbed places to carefully and suckled for between might be the fact that they can babies are independent, the colony hibernate in. four and five weeks until it is old conserve energy by hibernating. breaks up and the bats generally enough to fly out and hunt for itself. They also breed slowly, producing move to other roosts. Bats from a Surprisingly, bats don’t sleep right Bats don’t bring food back to the one baby a year, or every other year. wide area may gather together to through the winter but may wake up roost to feed their young, so the baby In contrast, a wild mouse will live form these colonies, so any disaster and go out to feed and drink on mild lives only on its mother’s milk until it less than two years, producing up at a summer breeding site can wipe evenings when some insects are is old enough to fly. to 100 young in that time. out all the local females. 6 7 During the winter, bats aren’t often • Hollow or damaged trees. Bats in buildings the largest colony ever found seen, but clusters of hibernating bats Bats roost in cracks, cavities or contained well over 1,000. Bats are occasionally found in hollow under loose bark throughout With the clearing of Britain’s choose their roosts quite carefully. walls when buildings are being the year. woodland, bats have had to adapt to During the summer, they look for demolished, and sometimes turn living in buildings. Many species sites which are warmed by the sun, up in buildings such as churches. Each species has its own preferred now rely heavily on buildings for so they are most often found on the Underground places such as caves, types of roost. Some are almost roosting, so their conservation south or west sides of buildings. mines and cellars can house always found in buildings, others depends very much on our tolerance Most species prefer to roost in quite important numbers of bats during rely on buildings during the summer and goodwill. Bats are usually small spaces and they’re not usually the winter and a few special sites and caves or mines during the temporary seasonal visitors to found in open, draughty areas. are used by several hundred bats winter, whilst others prefer trees. houses, a little like house martins. for hibernation. Bats are creatures of habit and tend They normally form maternity Pipistrelles, our smallest and most to return to the same sites at the colonies during May or June and common species, are almost Where do bats live? same time year after year. For this then leave during July or August always found roosting in the eaves reason, roosts are legally protected once the young bats are of houses, or under hanging tiles or During the summer, bats fly out to even if bats don’t seem to be living independent.

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