One of Europe’s most threatened butterflies has returned to its old haunts in Tyrone and Fermanagh, experts have revealed.
Ireland was considered one of the last bastions for the marsh fritillary in Europe after it became extinct in a number of countries, yet it had vanished from all but eight sites in Northern Ireland.
But new colonies have now been discovered in traditional farming country across the west of Northern Ireland, according to Butterfly Conservation, which is seeking the help of farmers in protecting the elusive insect.
Several large colonies were found in the past few years in both Fermanagh and Tyrone in grassland rich in the butterfly’s food plant, devil’s bit scabious, known locally as blue button.
Such pastures have vanished across large parts of Britain and Ireland due to agricultural changes and heavy grazing but are still to be found in Fermanagh and Tyrone and some other parts of the province.
Butterfly Conservation's Paul Kirkland said the experts had become very concerned about the marsh fritillary’s decline in Northern Ireland until a few years ago.
“There had been a massive decline in the Seventies and Eighties. Before that, they hadn’t been properly counted but there would have been dozens and dozens of colonies across Northern Ireland,” he said.
“Until a few years ago we were under the impression that we had lost virtually all of these colonies. We had about eight small, isolated colonies in the east of Northern Ireland that we knew about around counties Down and Antrim.
“Then there was an exciting development when we started finding colonies in the west, in Fermanagh and Tyrone. Some of them were found by DARD agricultural officers and some have come about as wildfarm proposals were made and marsh fritillaries were found on the sites.
“We've got a new focus on the area — we’re keen to get more people recording and raise the profile of the marsh fritillary.”
The butterflies are on the wing in May and June but it may be easier to find them now that their eggs have hatched into caterpillars.
“The caterpillars live together in a silk web where they stay together in late summer and autumn and through to early spring,” Mr Kirkland said.
“You have a silken web full of 100 or so caterpillars which are really conspicuous so it’s a really good way to look for things and do surveys.
“The fritillaries prefer low-level land with traditional cattle grazing but they can survive on other forms of managements. Fermanagh and west Tyrone are ideal with all those lovely flower-rich pastures so there is the potential for finding more colonies.”
Senior regional officer Catherine Bertrand said grant aid was available through agri-environment schemes to help farmers manage wildflower-rich meadows in a traditional, non-intensive way.
“By doing so, this butterfly and other species that depend on these meadows will remain here for future generations,” she said.
The group will launch its new advisory leaflet for farmers at the Fermanagh Show on August 4. The leaflet has been produced in conjunction with DARD and the Environment Agency.