Natterer's bat  (Myotis nattereri)

European populations are listed under Appendix II of The Bonn Convention (1), Appendix II of the Bern Convention (3), and Annex IV of the EC Habitats Directive (4). In the UK it is protected under Schedules 5 and 6 of the Wildlife and Countryside Act 1981 (5), and Schedule 2 of the Conservation Regulations 1994 (6).

This medium sized bat has a grey-brown back and whitish fur to the underside, a pinkish face and quite large ears that are pink at the base and browner at the tips (7), with a long narrow tragus (2). A characteristic feature of this species is the row of stiff hairs along the edge of the tail membrane (7).

Widespread in much of Europe, Natterer's bat is found throughout most of the British Isles north to the Great Glen Fault in Scotland, but is scarce throughout most of this range (2).

Found in woodland and pasture, Natterer's bat roosts in old stone buildings in the summer (7). They hibernate in winter and mainly use underground sites such as caves and mines for this purpose (2). They feed in open woodland, along hedgerows and waterside vegetation and in parkland (2).

Prey items include moths, flies and spiders. The species has great manoeuvrability at low speeds and tends to fly at heights below 5 meters (2). It seems to use a combination of hunting styles, including gleaning by landing and taking prey in flight from or close to surfaces (8). Mating tends to occur in late summer and autumn, when large swarms form at underground sites. Mixed-sex maternity colonies form between May and September (9); up to 25% of the bats in a nursery roost may be male (9). Towards the end of June a single young is produced which is fed on milk for around six weeks after birth, and left in a 'creche' as the mother goes out to hunt. Young bats may fly three weeks after birth and will be weaned and independent after six (2).

The reasons for the decline of this species include the loss and degradation of suitable habitat resulting from a number of factors including inappropriate management and pesticide use, which may decrease prey availability. Many bats are particularly susceptible to disturbance; destruction and/ or disturbance of summer and winter roosts is likely to have contributed to the decline (9).

The Natterer's bat has not been given priority status under the UK Biodiversity Action Plan. There has therefore been little co-ordinated monitoring and conservation work targeted at this species, but the National Bat Monitoring Programme does count Natterer's colonies (4). Suggested measures that should be taken include population monitoring and mapping, with careful monitoring of barn conversions (2), research into the detailed habitat requirements of this species in order to inform management, promotion of woodland restoration and creation providing connectivity between sites, and protection of important swarming and hibernation sites (9).Under the Wildlife and Countryside Act, 1981 it is an offence to intentionally kill, injure or take a bat, or to damage, destroy or obstruct access to roosts (5).

To find out more about the conservation of this and other British bats see:

• The Bat Conservation Trust: Species Information Sheet - Natterer’s Bat:
  http://www.bats.org.uk/publications_detail.php/215/species_information_sheet_natterers_bat
• The Bat Conservation Trust:
  http://www.bats.org.uk
• The Vincent Wildlife Trust:
  http://www.vwt.org.uk/index.php

Information authenticated by the Bat Conservation Trust:
http://www.bats.org.uk

• Colonies: groups of organisms living together, individuals in the group are not physiologically connected and may not be related, such as a colony of birds. Another meaning refers to organisms, such as bryozoans, which are composed of numerous genetically identical modules (also referred to as zooids or 'individuals'), which are produced by budding and remain physiologically connected.
• Hibernation: a winter survival strategy characteristic of some mammals in which an animal's metabolic rate slows down and a state of deep sleep is attained. Whilst hibernating, animals survive on stored reserves of fat that they have accumulated in summer. In insects, the correct term for hibernation is 'diapause', a temporary pause in development and growth. Any stage of the lifecycle (eggs, larvae, pupae or adults) may enter diapause, which is typically associated with winter.
• Tragus: a soft cartilaginous projection extending in front of the external opening of the ear. In bats it is thought to aid in the location of prey by generating many echoes, but the precise way in which this works is unknown.

1. UNEP-WCMC (January, 2002)
   http://quin.unep-wcmc.org/
2. The Bat Conservation Trust: Species Information Sheet - Natterer’s Bat (January, 2002)
   http://www.bats.org.uk/publications_detail.php/215/species_information_sheet_natterers_bat
3. Council of Europe: Bern Convention (January, 2002)
   http://conventions.coe.int/Treaty/EN/Treaties/Html/104.htm
4. Bat Conservation Trust. (2002) Pers. comm.
5. Naturenet (January, 2002)
   http://www.naturenet.net/law/index.html
6. Conservation Regulations 1994 (January, 2002)
   http://www.hmso.gov.uk/si/si1994/Uksi_19942716_en_1.htm
7. Wardhaugh, A.A. (1995) Bats of the British Isles.Shire Natural History, Aylesbury.
8. Altringham, J.D. (1996) Bats: Biology and Behaviour.Oxford University Press, Oxford.
9. Altringham, J.D. (2002) Pers. comm.