Bats in Ireland
Ireland, being cut off from Europe far earlier in its history than Britain, has fewer species of animals and this includes the bats. Currently, ten bat species are officially recorded from the island but two recent detector records, one from the east coast and one from the west, may indicate the presence of two others; barbastelle (Barbastella barbastellus) and noctule (Nyctalus noctula). However, these have yet to be verified, in the hand, by the local bat workers.
The country, through destruction of its forests over the centuries, has lost much wildlife, including its woodpeckers. In the past, these birds would have created roosting opportunities for bats, including noctules, which may also have been present at the time.
Today, Ireland’s largest bat is Leisler’s (Nyctalus leisleri), which is also the third most common species, despite its rarity in Britain. The fact that it is so common could probably be attributed to lack of competition from noctules and its adaptation to living in buildings.
Both Common (Pipistrellus pipistrellus) and soprano (P. pygmaeus) pipistrelles are common throughout the country and Nathusius’s pipistrelle (P. nathusii) has recently been discovered breeding in Antrim with further records from Armagh, Cork, Derry, Down, Fermanagh, Kerry, Laois and Wicklow. In time, the species may also be recorded from other counties as bat detectors and bat workers become more widespread.
The estimated population of lesser horseshoe bats (Rhinolophus hipposideros) in Ireland is thought to be 12,000. This would make it the highest national population of any European country. This species is only found along the western seaboard and is under threat from habitat destruction and loss of appropriate roost sites. However, The Vincent Wildlife Trust has leased or purchased several lesser horseshoe bat roosts to stabilise, repair and vandal-proof the buildings. These reserves are then monitored to ensure the bats are using them successfully. Currently, the Trust holds 23% of the known Irish population of this species in its reserves.
The Heritage Council has also purchased one lesser horseshoe bat roost in county Clare to safeguard it for future generations. This is the largest summer roost of the species known to date in the country.
The remaining, known, Irish species; Daubenton’s (Myotis daubentonii), Natterer’s (M. nattereri), whiskered (M. mystacinus), Brandt’s (M. brandtii) and brown long-eared bats (Plecotus auritus) are also currently being surveyed by Bat Conservation Ireland and distribution maps are being compiled from all records.
Knowledge of the Irish bat species has suffered from lack of interest from the public. This has meant that some species have been overlooked or mis-identified over the years. Now, with the growth of interest in bats, groups are being formed to study bats in their local area. There are currently five bat groups on the island; Cork, Clare, Dublin, Galway and Northern Ireland and others are being formed. These give support to roost owners, liaise with timber treatment companies and building firms, promote bats through talks and care for injured or grounded animals. It is hoped that the bat group network can be widened, in the near future, to other counties, especially in the midlands.
As the interest in bats, and bat groups, increases, it is to be hoped that a clearer picture will emerge of the conservation issues and threats facing Irish bats and also that vagrant or ‘new’ species can be identified. This will be increasingly important because of species such as barbastelle (categorised on Annex II, of the Habitats Directive) as it has implications for designation of Special Areas of Conservation.
There are many threats facing our bat species; loss of roost sites and habitat destruction being the primary ones. Bats are forced out of buildings when old properties are renovated or when excluded from dwellings through fear or indifference. The destruction of hedgerows and tree lines has a direct impact on local bat populations due to loss of sheltered feeding areas or commuting routes.
The use of pesticides and insecticides on the land is reducing the available food and bats are ingesting large quantities of these poisons through their prey. A tiny pipistrelle can eat up to 3,500 midges per night. In heavily treated areas this can amount to 3,500 doses of poison. Chemicals used in eradicating lice in cattle survive in the cow's dung where they prevent insects' eggs from hatching. Consequently, there are now less dung beetles and flies for the bats to eat.
Bats also suffer from timber treatments within attic spaces. These poisons are sprayed on the wood to prevent furniture beetle or fungi and, as a bat's wing is a large area of skin laced with blood vessels, any poisons that it contacts on the timber are absorbed directly into the bloodstream. The treatments on the market are now less toxic then in the past but care still needs to be taken when applying then in or near bat roosts. Preferably, treatment should be put off until the winter months when most bats will not be present.
These animals are also very intelligent, long-lived creatures. Although many die in their first year and the average lifespan in the wild is four years, some will live up to 40 years and beyond. This is important, as some bat species have to be four years old before they are sexually mature and able to reproduce. All the Irish species give birth to only one offspring. Usually in early June but the birth is dependent on ambient temperatures and the development of the young can be slowed so that birth occurs at the optimum time of greatest insect abundance. All bats feed their babies on breast milk and the young bat grows rapidly and is weaned within six or seven weeks.
The juvenile then has to attempt to fly, catch insects, find roosts and put enough fat on its body to live through its first winter. Mortality is often high especially for those born late as they have less time to accumulate the required fat reserves to get them through their first hibernation period.
It is usually the young and weak that fall foul of the family cat in July or August. Many are deposited, either dead or alive, on the kitchen floor. When this happens, the little bat should be examined for injuries and, if none are apparent, it should be retained in a secure container and released outside at dusk. If it is injured, it should be taken to a veterinary surgeon for treatment. Bats are completely harmless; none of the Irish species have any known diseases and they are very clean animals as they groom constantly. Their droppings, which can accumulate in some situations, are totally innocuous.
It should also be remembered that bats neither gnaw wood nor chew electric cabling. As they are not related to rats or mice (they are not rodents) they have no front teeth. They simply hang from or squeeze into any available crevice in the roof of a building. Unlike birds, they do not bring in nesting material. They are seasonal visitors to our homes for the summer months but may be resident in a building for many seasons without the owner even knowing as most will be in the eaves and not in the attic proper. Should one have bats actually living in the attic space it is a worthwhile idea to cover the water tank to prevent accidental drowning.
All bat species, in the Republic, are protected under the Wildlife Act 1976 and Amendment 2000. In Northern Ireland, the Wildlife (Northern Ireland) Order 1985 serves the same purpose. This legislation makes it an offence to injure or kill bats or destroy their roosts. To enforce the Wildlife Act, Conservation Rangers are employed by the National Parks and Wildlife Service in the Republic and, in Northern Ireland a Wildlife Liaison Officer has been appointed by the Police Service to oversee the 1985 legislation.