An Essex Skipper, recently found in Ireland (source)
Wildlife and Fauna
The number of butterfly species found in Ireland has grown in recent years. Some species appear to be colonising the country from Britain, some may have been here all along but they are so similar to other species that their presence went undetected. An example of this category is Réal's wood white, a species found here and in France, but not in Britain. To tell a Réal's wood white from an ordinary wood white you have to examine it with a powerful hand lens or a microscope, and this wasn't done in Ireland until the year 2000. The comma is expanding its range in Britain and has started turning up in Ireland. If it breeds and spreads it will be an example of a colonising species. Two small butterflies, the Essex skipper and the small skipper, may be colonisers or they may have been here all the time in small numbers without being recognised.
If we exclude the extreme rarities that get blown over here from time to time but include these new species the total comes to thirty-five. Some of these species migrate to Ireland in the summer from continental Europe. The red admiral and the painted lady are regular visitors, the rarer clouded yellow only makes it in some years. Other species, like the small white, are partially migratory, with large numbers arriving across the Irish Sea from Wales in some years.
Butterflies in Ireland, and across Europe, have suffered from habitat loss in recent decades and numbers have declined. The main reason is that changing farming practices have reduced the number of wild flowers that butterflies need for nectar and, even more crucially, the particular food plants of their caterpillars. The unimproved grassland along canal banks can provide a significant refuge for many species if it is sensitively managed.