Bats in Cornwall

Much of our current knowledge of bats is relatively recent, and for many years all bats were just ‘bats’. In the Cornish language askel grohen (literally leather wings) covers all the bat species. Now more than 1000 different bat species are known to science, although only 17 have been identified as breeding residents in the UK. Thirteen of these species have been recorded in Cornwall, of which twelve are known to breed in the county. In addition, there are occasional vagrants such as the European free-tailed bat found, exhausted and grounded, by a dog-walker in Helston in 2003 and in 1985 a Kuhl’s pipistrelle was found, grounded, at St Blazey.

 

Although bats make up a quarter of all the UK’s resident mammal species, their small size, nocturnal life-style, and elusive habits have meant they have been relatively little studied until recently. Indeed, new bat species are still being identified: grey and brown long-eared bats were only identified as separate species in the 1960s, ten years later it was the turn of the whiskered and Brandt’s bats to be divided, and in the 1990s it became apparent that the common pipistrelle was in fact two discrete species. To add to the confusion, the alcathoe bat has recently been identified as a UK resident. This species is very similar to the whiskered and Brandt’s bat and so it may yet be added to the Cornish list. In addition to the 13 species covered in the atlas there are also unconfirmed reports of both Leisler’s bat and the grey long-eared bat.

© Neil Reeves

© David Chapman

© David Chapman

It is generally accepted that bat numbers in the UK and across Europe have fallen dramatically over the last century. The factors that impact bat populations are common to all species at some level. Environmental change as a result of changing farming practices, and development, has led to a loss of feeding and roosting sites. Unimproved grassland, natural woodland, and ponds all provide feeding opportunities and these have made way for larger fields, housing and roads. Old trees, where most bats would originally have spent their summer months, are often felled for timber or fuel or tidied away for safety reasons. Old buildings may be demolished or repaired, removing roost sites. The treatment of roof timbers with organochlorine chemicals such as lindane to control woodworm infestation wiped out many colonies of bats. It was found that the chemicals rapidly killed bats even if they were not present during the actual spraying. Lindane is now banned in Europe and disturbance of bats by roof treatments is subject to control under UK legislation. In Cornwall, old mine buildings often provide useful roost sites but many of these have been lost. In rural areas barns and agricultural outbuildings are often converted to housing with the loss of breeding roosts. Bats are dependent on undisturbed hibernation sites and relatively little is known about where many species spend the winter. In Cornwall, capping of mines in the 1970s did not take into account the needs of the bat roosts and thousands of old shafts were sealed. Bat 87 access is now taken into account in mine capping in the county. The fragmentation of countryside can lead to isolation of bat populations and separation of roost sites from feeding areas, meaning the bats have to travel further and expend more energy. Increased lighting in built-up areas and around roads can disturb bat behaviour, even though sometimes bats are seen pursuing moths around street lights. The constant drive for more efficient agriculture has resulted in larger fields with fewer hedgerows. The hedges not only provide a source of insect food for the bats, but they have also been shown to be important in how the bats move around the landscape. Mechanisation, herbicides, and pesticides all support apparent agricultural efficiency; but in doing so reduce the number and variety of insects available for bats to eat. In the last 40years moth numbers have fallen by nearly half, and many species have become extinct in the UK.

The realisation that bats were under threat from so many sides has resulted in extensive protection for bats and their habitats from European and national governments. Specifically, article 12(1) of the Habitats Directive 1992 EEC states that Member States shall take the requisite measures to establish a system of strict protection for the animal species in Annex IV of the Directive, which includes all of the UK’s bats. This extends to prohibition of:

 

  • All forms of deliberate capture or killing of the species in the wild.

  • Deliberate disturbance of these species, particularly during the periods of breeding, rearing, hibernation or migration.

  • Deterioration or destruction of breeding sites or resting places.

 

Under the Conservation of Habitats and Species Regulations, 2010 (as amended) it is an offence to:

 

  • Deliberately capture, injure, or kill a bat.

  • Deliberately disturb an animal. This includes disturbance likely to impair ability to survive, breed, or rear young, hibernate, or migrate, or disturbance that would significantly affect local distribution or abundance of the species.

  • Damage or destroy a roost.

  • Possess, control, transport, sell, exchange or offer for sale or exchange any live or dead bat or any part of a bat.

 

Under the Wildlife and Countryside Act 1981 (as amended) it is an offence to intentionally or recklessly:

 

  • Disturb a bat whilst it is in a roost

  • Obstruct access to a roost.

 

In particular circumstances licenses may be issued by the licensing authority (Natural England) for development or survey work which might otherwise be in contravention of the above legislation. The issue of these derogation licences is subject to the following three conditions:

 

  • The activity to be licensed must be for imperative reasons of overriding public interest or for public health and safety.

  • There must be no satisfactory alternative.

  • Favourable conservation status of the species must be maintained.

 

Up to date information on the legal protection of bats in England can be obtained from Natural England.

© David Chapman

Bat Watching:

 

Monitoring and surveying of bats is carried out for reasons other than planning control. The Bat Conservation Trust organises a National Bat Monitoring Programme which calls on numerous volunteers to survey maternity roosts, hibernation roosts, and habitats across the country. Since it began in 1996, essential data has been collected to record changes in bat species and populations. The programme is beginning to show changes in bat numbers and it is reassuring to see in the 2011 report that all the monitored species were stable or increasing, albeit from a very low level. Surveys of roosts or hibernation sites are the preserve of trained and licensed bat workers but it is still possible to search for, and study, bats without a licence, providing the animals are not disturbed in any way (but note that disturbance includes photography of roosting bats). Bats usually emerge at dusk from their summer roosts. When they are using buildings or trees they may leave tell-tale traces such as droppings or grease stains where they leave. Watching these exits against the evening sky may reveal bats entering or leaving, especially early risers such as the noctule and pipistrelle. Sometimes bats will use a feeding roost to eat captured insects and these may be revealed by discarded moth wings and droppings. It is also possible to watch bats as they hunt over suitable habitat – good sites to watch are unimproved grassland, especially near ponds and rivers, and woodland glades or edges. When the light fails the only way to monitor bats is to listen out for their calls – those of us lucky enough, and young enough, to have good hearing may be able to hear some bat calls but for most of us a bat detector is needed.