Greater
horseshoe bat:
Rhinolophus ferrumequinum
The horseshoe bats can be distinguished from other British bats by the presence of a complex horseshoe shaped noseleaf which is related to their particular type of echolocation system. When roosting they hang free with the wings more or less enfolding their body. The greater horseshoe bat is one of our largest species - the size of a small pear.
Greater horseshoe bat facts
| Description | |||
| Head and body length |
57 - 71mm | ||
| Forearm length | 54 - 61mm | ||
| Wingspan |
350 - 400mm | ||
| Weight |
17 - 34g | ||
| Colour |
Adults buff-brown; juveniles greyish | ||
| Life cycle | |||
| Mating period | Late September to October | ||
|
Maternity colonies |
Late spring. Young: usually one born mid-July, weaned within 7 weeks | ||
|
Colony size |
50 - 200 (rarely 600) | ||
| Longevity |
Up to 30 years | ||
| Habitat and food | |||
|
Summer roosts |
Mainly buildings | ||
| Winter roosts | Caves, disused mines, cellars, tunnels | ||
|
Feeding habitat |
Deciduous woodland, scrub, permanent pasture | ||
|
Typical food | |||
| Cockchafer beetles | Dung beetles | Large moths | Caddis flies |
Greater horseshoe bats emerge from their roosts within half an hour of sunset. Between May and August they usually return to their roost after about an hour and remain there until their second feed around dawn. However, from late August they may remain away all night.
Insects are taken in flight or occasionally from the ground. Greater horseshoe bats often behave like flycatchers, "watching" from a regular perch and flying out to take passing insects. Large prey is taken to a regular feeding perch; insect remains beneath such perches in trees, porches or cave entrances are most evident in spring or autumn. Greater horseshoe bats feed mainly by low-flying hunting.
Breeding
Mating occurs during the autumn, but can take place in late winter or even spring. Maternity colonies begin to gather in May and reach peak numbers in mid-June to July when most breeding females return. Males up to 14 years old return with breeding females in June, but most leave when the young are born in mid-July.
Birth often occurs at dusk. The female hangs from her feet and the single baby emerges into the overlapped wings. Shortly afterwards the young is left in the roost, while the mother flies off to feed. The young can open their eyes at nine days of age. At first the young feed on their mothers milk, but after about five weeks can fly and start to catch insects. They are fully weaned at seven weeks when the adults usually leave the colony but juveniles and some immature bats may stay until October or even later.
Female greater horseshoe bats are not usually sexually mature until their third year and one female did not breed until its tenth year. They may not breed every year. Males are usually sexually mature by their second or third year.
Summer roosts
Greater horseshoe bats were originally cave dwellers, but few now use caves in summer - most breeding females use buildings, choosing sites with large entrance holes with access to open roof spaces warmed by the sun. Such sites are usually in larger, older houses, churches and barns. A range of other sites is used in spring, and males hold territory at mating roosts in autumn.
The bats from clusters inside maternity roosts to keep warm, but will spread out if the roost gets too hot. Maternity colonies can be noisy with continuous chattering, chirping and scolding calls. Males also use caves and tunnels in the summer and even the breeding females appear to need a nearby cave or tunnel to retreat to when bad weather affects their food supply.
Winter roosts
The greater horseshoe bat uses caves, disused mines, cellars and tunnels as hibernation sites. These sites can be up to 50km (30 miles) from the breeding roost. They may hibernate from late September to mid-May, depending on the weather and food availability. They awake from hibernation at frequent intervals and, in their search for suitable temperatures, movements of 30km (17 miles) between sites are often recorded. They will feed in winter during mild weather.
Hibernation sites are much warmer than those of many other bats, with temperatures varying from about 11°C in October top about 7°C in February, although this varies with age, sex and body condition. They will sometimes form clusters in winter sites, although adult females are more solitary.
Generally, female greater horseshoe bats are found deep within the hibernaculum and move little throughout the winter. Females are usually much fatter and can afford to find a much warmer place to hibernate. The males however, often keep nearer to the entrance and frequently move site. Immature greater horseshoe bats are highly gregarious at all times and can form groups with adult males of up to 300 in winter.
Ultra-sound
Greater horseshoe bats have an almost constant frequency call of about 82kHz. On a bat detector a series of continuous warbles can be heard.
Status and distribution
The greater horseshoe bat has shown a marked decline, particularly in western and northern Europe. It is rare in Britain and now confined to south- west England and South Wales. It is estimated that the number of greater horseshoe bats has declined by over 90% in the last 100 years.
Conservation
The decline of the greater horseshoe bat may be due to factors such as disturbance of roosts and intensive agricultural practices including loss of permanent pasture. They are particularly sensitive to disturbance at their nursery and winter roosts. These sites need to be specifically protected and entrance holes left unobstructed.
The conservation of their feeding habitats and food sources is also important. The use of pesticides has led to a decrease in availability of larger beetles, particularly cockchafers, and moths over large areas of the countryside.
If you have any questions about any of these pages then:-
Please feel free to e-mail me on info@gardenwildlife.co.uk
Or please talk to others in my wildlife Discussion Forum or Chat Room
