Another Life: Don’t be put off by silly myths. Bats are keystone mammals

A clear night in June never quite manages the final fade to black, and a trip to the loo at 4am found the sky above the ridge a lovely deep denim blue. Against this cerulean glow our bats were still out hunting, scribbling dizzy circles between the trees and the woodshed. By day our nesting swallows sift this airspace of midges, but for now it was the pipistrelles, snatching perhaps 3,000 each – so the books say – before retiring to doze somewhere above my workroom ceiling.

I can still guess at pipistrelles with the odds on my side, but the number of Ireland's bat species goes up and up. When the zoologist James Fairley produced his first Irish Beast Book, in 1975, there were still seven known kinds of Irish bat: the common pipistrelle; whiskered bat; long-eared bat; Leisler's, Daubenton's and Natterer's bats; and the lesser horseshoe. These had been known from dead or captured bats, plus different insects in their droppings, since the end of the 19th century.

By the late 1990s came the little pocket yokes for detecting the distinctive echolocation pulses of different bat species. Some pipistrelles were pulsing to a higher pitch, and the new “soprano” pipistrelle was further confirmed by its different DNA.

Later, in the north, a super bat detector picked up Nathasius’s pipistrelle, a migratory European species well known but never before found in Ireland. In 2003 Brandt’s bat, a woodland species long sought here, was found by a wildlife ranger at Glendalough, Co Wicklow, sadly stuck to a newly painted fence. And in February this year came the first greater horseshoe bat, a warmth-loving species with a wingspan of some 30cm – a single male, roosting in an old farm building in Co Wexford.

So 11 bats now instead of seven, counting in the rare and odd. “From about 1920 until 1980,” wrote Prof Fairley later, “is largely a void in the study of Ireland’s bats.”

Busy study that sprang up thereafter owed much to his enthusiastic tutelage at NUI Galway. He inspired women students in particular, among them Dr Kate McAney, who, as Irish field officer for the Vincent Wildlife Trust, has protected the roosts of Europe's surviving lesser horseshoe bats in their precious refuges in Connacht. (The face in my drawing shows the distinctive nose flap.) Others in Dr Fairley's chiropterological clan went on to enrich further bat research and conservation.

University College Dublin, in its turn, has produced another mad-keen batwoman (as she suffers being called) in Prof Emma Teeling, founder and director of the Centre for Irish Bat Research, an initiative between UCD and Queen's University Belfast, and conservation is high among its aims. One of her PhD students at UCD, Una Nealon, is studying the impact of wind farms on bats in Ireland.

Bat casualties totalling thousands have been reported from wind farms in the US and Canada, caused less often by direct impact than through barotrauma, a fatal overexpansion of the lungs from a sudden change in air pressure at the spinning turbine blades. Other deaths have been mounting in Europe and a few, mainly of pipistrelles, in Scotland.

The highest risk is run by bats migrating seasonally over continental distances, as in America and eastern Europe. In Ireland the only known migrant is Nathusius' pipistrelle, which flies between Scandinavia, Scotland and Northern Ireland. And while more of American bat species seem to be killed as turbines get taller, most of Ireland's bats are normally low flyers, just a few metres off the ground. (Leisler's bat appears an exception, between dives after cowpat dung flies.)

Measured bat activity
Nealon's research, funded by the Sustainable Energy Authority, has measured bat activity at Irish wind farms, where common and soprano pipistrelles were by far the busiest bats; she has yet to start recording and analysing casualties.

Meanwhile, Bat Conservation Ireland, umbrella NGO for the many local bat groups, has been working with the Centre for Irish Bat Research, local authorities and wind-farm developers to make bat protection an issue in planning turbine sites.

A score of Irish county councils, from Donegal to Waterford, helped to fund a survey to map the core habitats of different species. Bat Conservation Ireland then offered guidelines, framed “in consultation with industry stakeholders”, on surveying proposed wind-farm sites to prevent dire impacts on the bats and their roosts, feeding areas and flight paths.

Such potential deaths and declines may seem slight or problematic compared with existing impacts. Pesticides, chemical treatment of roof timbers and the loss of old but sheltering buildings have all done their harm. But, however belatedly, Ireland has been educated on the interest and value of a keystone little mammal, long proscribed from public favour by silly myths and fears. If a little more expert care can keep bats flying free and safely in the night sky, let’s do it.