In search of missing butterflies

BUTTERFLIES need your help.

There are worries about their plight, not only in Ireland but throughout Europe; the numbers of grassland species in some parts of the EU are now half what they were in 1990.

A similar loss has occurred here, but no figures are available. Now a project is underway to find out how our butterflies are faring; Dr Eugenie Regan, speaking on RTÉ’s Mooney Show recently, appealed for volunteers to help out.

Butterflies are almost unique among insects in that everybody loves them. These animal equivalents of flowers evolved alongside the plants which they help to pollinate. In Irish folklore, they were the souls of dead people and it was unlucky to harm one. The red admiral butterfly, however, was thought to be the devil and was persecuted.

The first attempts to monitor butterfly populations began in Britain in 1976. It’s impossible to count butterflies accurately over a large area, censusing is not an option, so a “transect” methodology has been developed.

Volunteers walk a chosen route once a week between April and September, recording every butterfly species seen and the numbers of each. Transect counts can’t tell researchers how many butterflies we have but, if the same routes are walked repeatedly year after year, changes occurring in butterfly numbers soon show up. A decline in the population of a particular species, for example, would become evident. Schemes are up and running in 14 countries with 2,500 transects being made annually in Europe. Volunteers walk about 40,000km in a season, which is more than a circuit of the globe, according to the Dutch entomologist, Chris van Swaay.

Ireland joined the project in 2006 when six transects were covered. This had increased to 39 by last year, with a total of 16,279 butterflies counted. It’s proposed to double the number of transects this summer, but there is a shortage of observers, particularly in rural areas.

The centres of population do rather better; Dublin has 11 volunteers and there are six each in Cork and Waterford. Donegal has three, but 13 counties have no participants at all.

Twenty-eight species were recorded along transects in 2008, the commonest being the speckled wood butterfly with just under 3,000 seen. Meadow browns and green-veined whites were also fairly abundant. No species occurred at all 39 locations. The Raven nature reserve in Wexford, with 20 species, had the largest number recorded.

It’s up to each volunteer to chose the site he or she will cover. Most people opt for a route between one and a half and two kilometres long, requiring an hour at most to walk. Ideally, a location should include different habitats and the transects should be made between 11 o’clock in the morning and four in the afternoon.

Learning to identify butterflies is easy; we have 35 breeding species but only about 20 of them occur widely in the countryside. Three new species, common in Britain, turned up recently and a half dozen exotic migrants from abroad visit us occasionally, but none of these is likely to be encountered.

In any case, identification charts and notes are supplied to volunteers and some excellent field guide books are available.

Pat McCusker’s The Butterflies of the Killarney National Park, published by the Wildlife Service, gives an brief account, with illustrations, of the 23 species recorded there to date.

Not all Irish butterflies are featured, but the commoner ones are and this booklet is useful anywhere in the country. Michael Chinery’s Pocket Guide to the Insects of Britain and Western Europe covers most of the butterflies you are likely to see, while Tolman and Lewington’s Butterflies of Britain and Europe, also published by Collins, is comprehensive.

Discovering Irish Butterflies by JM Harding gives an excellent account of the ecology of each species and detailed instructions on how to attract butterflies to your garden.

Photographs give an indication of what each species looks like but this book is not a field guide. A chapter on places to visit details some of the best butterfly-watching locations in the country.

It’s not too late to participate this year, so contact the Irish Butterfly Monitoring Scheme; [e-mail]. The project is sponsored by the Heritage Council under the auspices of the National Biodiversity Data Centre.