Grey long-eared bat (Plecotus austriacus)

Also known as: Gray big-eared bat
  
French: Oreillard Gris
Spanish: Orejudo Gris
KingdomAnimalia
PhylumChordata
ClassMammalia
OrderChiroptera
FamilyVespertilionidae
GenusPlecotus (1)
SizeEar length: 31 - 41 mm (2)
Wingspan: 225 - 300 mm (2)
Head-body length: 41 - 58 mm (2)
Tail length: 37 - 55 mm (2)
Forearm length: 37 - 45 mm (2)
Weight7 - 14 g (2)

The grey long-eared bat is classified as Least Concern (LC) on the IUCN Red List (1). In Great Britain, all bats are fully protected under Schedule 5 of the Wildlife and Countryside Act (1981) as amended, and by the Conservation Regulations (1994) (3). An agreement on the Conservation of Bats in Europe (EUROBATS) under the auspices of the Bonn Convention, also known as the Convention on Migratory species (CMS) is in force, and all European bats are listed under Appendix II of the CMS (4).

The grey long-eared bat (Plecotus austriacus) is one of Britain's rarest mammals. It is very similar in appearance to the brown long-eared bat (Plecotus auritus), and was only rediscovered in Central Europe in 1960 (5). As the common names of both species suggests, these bats have strikingly large ears (2). The grey long-eared bat has long grey fur; the belly is paler (2). The eyes are fairly large, the nose and upper lip are greyish to black, and the ears and wing membranes are blackish in colour (2).

In Europe, the grey long-eared bat is widespread and fairly abundant in the south, is less common than the brown long-eared bat in central areas, and rare in the northwest (6). In Britain this species is very rare (6), and is known only from the southwest and the coasts of southern England, it also occurs in the Channel Islands and on the Isle of Wight (6). Although probably always rare, several British populations have become extinct in the last 30 years (6).

The grey long-eared bat has a strong preference for warm lowland areas, tending to inhabit cultivated areas and valleys below 400 metres (6). Summer roosts are in buildings, and hibernation occurs in caves, mine tunnels and cellars (2).

Bats are the only true flying mammals. In Britain they are insectivorous (eat insects), and contrary to popular misconception they are not blind; many can actually see very well (7). All British bats use echolocation to orient themselves at night; they emit bursts of sound that are of such high frequencies they are beyond the human range of hearing and are therefore called 'ultrasound' (6). They then listen to and interpret the echoes bounced back from objects, including prey, around them, allowing them to build up a 'sound-picture' of their surroundings (6). Grey long-eared bats are nocturnal, emerging from their roosts only after nightfall (2). They are extremely skilful fliers, and hunt for flying insects such as moths, small beetles and flies (2) (8). Like the brown long-eared bat, the grey long-eared bat may take prey items to a perch to be eaten (2). Little is known of mating behaviour and reproduction in this bat. The mating season occurs in autumn, during which time males are territorial (6). Fertilisation is delayed until the following spring (6). Summer maternity roosts are small, containing 10 to 30 females, and a single young is produced in mid to late June (2). Hibernation takes place between September and April (7). The grey long-eared bat can live to a maximum of 14.5 years (2), but average ages of five years for males, and nine for females are more realistic (6).

Like all bats, the grey long-eared bat is vulnerable to a number of threats, and is at particular risk from harsh winters in Britain (6). Habitat change and loss, affecting the availability of insect prey and causing the fragmentation of feeding habitat is a serious problem for many bats, furthermore pesticide use has devastating effects, by causing severe declines in insect prey abundance, and contaminating food with potentially fatal toxins (4). Insecticides applied to timbers inside buildings where roosts occur are a particular danger, the initial treatment can wipe out whole colonies (spraying timber where bats are roosting is now illegal), but the effects of these chemicals can be lethal to bats for up to 20 years (4).

In Britain, bats benefit from a very comprehensive level of legal protection (4). Under the Wildlife and Countryside Act of 1981 it is illegal to intentionally kill, injure, take or sell a bat, posses a live bat or part of a bat, to intentionally, or in England and Wales, recklessly damage obstruct or destroy access to bat roosts. Under the Conservation Regulations it is an offence to damage or destroy breeding sites or resting places. Fines of up to £5,000 per bat affected and six months imprisonment are in place for these offences (3). Several species of bat also benefit by the public putting bat boxes up.

For more on British bats, their conservation and how to help: 

Authenticated (2002) by Amy Dunkley, The Bat Conservation Trust, London.
http://www.bats.org.uk

  1. IUCN Red List (March, 2011)
    http://www.iucnredlist.org
  2. Schober, W. and Grimmberger, E. (1987) A Guide to Bats of Britain and Europe. Hamlyn Publishing Group Limited, London.
  3. Bats and the Law - a quick guide. Bat Conservation Trust (August, 2002)
    http://www.bats.org.uk/
  4. Morris, P. (1993) A Red Data Book for British Mammals. Mammal Society, Bristol.
  5. Dunkley, A. (2004) Pers. comm.
  6. Macdonald, D.W. and Tattersall, F.T. (2001) Britain's Mammals: The Challenge for Conservation. The Wildlife Conservation Research Unit, Oxford University, Oxford. Available at:
    http://www.wildcru.org
  7. Altringham, J.D. (1996) Bats: Biology and Behaviour. Oxford University Press, Oxford.
  8. People’s Trust for Endangered Species. Grey long-eared bat fact sheet (March, 2008)
    http://www.ptes.org/index.php?page=142