Collins New Naturalist Library. L. Matthews Harrison

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      Fig. 1. Side and front views of the head of a horseshoe bat to show the details of the nose-leaf.

       Family Rhinolophidae

      Two species of this family are members of the British fauna, the greater and lesser horseshoe bats, Rhinolophus ferrumequinum and R. hipposideros. They are characterised by the possession of ‘nose leaves’, thin fleshy outgrowths arising round the nostrils but overlapping the fur of the face with their free outer parts. Their structure is complex and better described by a drawing than by words; the part over the muzzle and round the nostrils is crescentic in shape, hence the English, Latin, and latinised Greek names of these bats.

      The nose leaf is part of the special echolocation system. The greater horseshoe bat has a wingspan of 34 to 39 centimetres and is thus one of our larger bats. Its natural roosts are in caves, but it also uses mines and the cellars and roof spaces of buildings. In the British Isles it is found only in southwest England and south Wales. The lesser horseshoe bat is one of our smaller species, with a wingspan of only 22 to 25 centimetres. It roosts in similar places to those used by the larger species, and has a larger range, being found in southwest England, all of Wales and extending into Yorkshire, and far to the west in western Ireland.

       Family Vespertilionidae

      All the other British bats belong to this family – fifteen species in seven genera. They are mostly small to medium-sized bats but the serotine and noctule equal the greater horseshoe in wingspan, and one, the rare mouse-eared bat exceeds it by up to six centimetres.

      Of the fifteen species, six are common throughout much of the British Isles, though only one, the pipistrelle, is found everywhere except in Shetland; they are the whiskered, Natterer’s, Daubenton’s, noctule, pipistrelle, and long-eared bats. Five species are rare, or occasional vagrants – Bechstein’s, the mouse-eared, parti-coloured, Nathusius’ pipistrelle, and the grey long-eared bats. The remaining four species are intermediate, having a limited distribution within the bounds of which they may not be scarce. They are Brandt’s, the serotine, Leisler’s and the barbastelle bats.

      Six species of the genus Myotis are British. The whiskered bat, M. mystacinus, is a small dark grey bat that roosts in trees and buildings and often hibernates in caves. It is found throughout England, Wales and Ireland, but is less common in southern Scotland and absent from the north. Brandt’s bat, M. brandti, so closely resembles the whiskered bat that it has only recently been recognised as a separate species, differing slightly in details of the ear and teeth; it is known from many parts of England and Wales but its overall distribution has yet to be ascertained. Natterer’s bat, M. nattereri, is larger, with a wingspan of up to 30 cm, and the fur brown above and light or white below. It can be distinguished from all others by the fringe of stiff short hairs along the edge of the bare skin joining the legs and tail – the interfemoral part of the patagium or double layer of skin that makes a bat in effect an aerofoil. It roosts in trees, buildings and caves throughout the British Isles as far north as central Scotland. Bechstein’s bat, M. bechsteini, very similar to Natterer’s bat but having longer ears and lacking the fringe of hairs on the interfemoral patagium, is a rare woodland bat that has occasionally been found in southern England, mostly in Dorset. The mouse-eared bat, M. myotis, our largest species with wingspan up to 45 centimetres, was known only as a rare vagrant until 1956 when a small colony was found in a cave in Dorset; another was found in Sussex fifteen years later. Daubenton’s bat, M. daubentoni, is medium in size, dark brown above and pale grey below. The ear is comparatively short, and the feet large. It is often seen catching insects flying low over water, but is by no means confined to this way of feeding and frequently hunts in other places. It roosts in hollow trees and buildings, and often hibernates in caves. It is found throughout the British Isles except the northern parts of Scotland and the Hebrides.

      Of the genus Vespertilio only the parti-coloured bat, V. murinus, has been found in the British Isles, as a very rare vagrant from the continent. It is a medium-sized bat; the dark brown hairs of the back have white or buff tips which give a grizzled or speckled appearance. Similarly, the genus Eptesicus has only one British species, the serotine bat, E. serotinus, which is, however, a regular though localised member of the fauna. It is a large species with a wingspan of up to 38 centimetres, and has dark brown fur, paler below. It is mainly a woodland species but often roosts in buildings; in England it is found only in the southern and eastern counties as far north as the Wash.

      Two species of the genus Nyctalus, the noctule N. noctula, and Leisler’s bat N. leisleri, are widespread though not universal in the British Isles; both have comparatively narrow pointed wings. The large noctule with a wingspan of up to 39 centimetres has dark yellowish or reddish brown fur. It is a woodland bat, roosting in holes in trees, and often flies well before dark, hunting high above the trees. It occurs throughout England and Wales, rarely in southern Scotland and is absent from Ireland. The smaller but similar Leisler’s bat on the other hand is found throughout Ireland but has a more restricted distribution in central and southern England. It, too, is a woodland bat, differing from the noctule not only in its smaller size but also in the colour of the fur on the back, which is reddish brown at the surface but dark brown at the bases of the hairs.

      The pipistrelle, Pipistrellus pipistrellus, a small bat with a wingspan not over 25 centimetres, is our commonest species, being found throughout the British Isles with the exception of Shetland. It varies greatly in colour, ranging from rufous through shades of brown to almost black. It roosts commonly in buildings, in which its colonies may number several hundred animals. The closely similar Nathusius’ pipistrelle, P. nathusii, is slightly larger, but is known only as a vagrant, a single specimen having been found in Dorset in 1959.

      The barbastelle, Barbastellus barbastellus, the only British member of its genus, is a medium-sized bat with black fur, the lighter tips of the hairs giving a frosted appearance. The ears are short but wide and joined at their bases above the face, thus differing from all other British species except the long-eared bat. Barbastelles roost in hollow trees and buildings, and sometimes hibernate in caves. The species is rather thinly distributed over England and Wales as far north as Cheshire and Yorkshire, and is generally regarded as uncommon.

      The long-eared bat, Plecotus auritus, is a small species recognised by its enormously long narrow ears which are nearly as long as the head-and-body. When asleep it tucks the ears under the wings leaving the tragus, the lobe representing the ear-cover, of each side sticking up like a pair of spikey horns. It roosts in trees and buildings and frequently hibernates in caves; when feeding it often hovers to pick insects off the leaves of trees. It is widely distributed throughout the British Isles except in northern Scotland СКАЧАТЬ