
The future didn’t seem bright for the white-letter hairstreak, a rare butterfly native to the UK. With its population plummeting by 96 percent since the 1970s due to habitat destruction, this butterfly had not been seen in Scotland since 1884. So, it was a shock when lepidopterists saw a white-letter hairstreak feeding in a field in Berwickshire, Scotland, earlier in August, as reported by The Guardian.
Iain Cowe, the man who spotted the butterfly, managed to snap a photograph of it. “It’s not every day you find something as unique as this while out on a routine butterfly outing,” Cowe said in a statement from the UK’s Butterfly Conservation. “It was an old, worn butterfly feeding on ragwort at the edge of a cultivated field.”
The white-letter hairstreak is a small brown butterfly featuring a white “W”-shaped mark on its wings and a small orange spot on its hindwings. It’s a hard butterfly to spot since it usually stays hidden, feeding and mating high up in the trees.
The white-letter hairstreak favors the elm tree as its natural habitat, but the spread of Dutch elm disease, first recognized in the 1970s, led to the destruction of millions of elms across Britain. As a result, this threatened butterfly species had to find new places to live and sources of food. Over time, it has gradually moved north, and experts are optimistic that Scotland could provide a suitable environment for the butterfly. Although Dutch elm disease is present in Scotland, the country is home to many disease-resistant Wych elms.
If a breeding population of white-letter hairstreaks is established, Scotland’s butterfly species count will rise to 34. “We don’t have many butterfly species in Scotland, so adding another is very welcome,” said Paul Kirkland, director of Butterfly Conservation Scotland, in a statement.
Before 1884, the only verified sighting of a white-letter hairstreak in Scotland occurred in 1859. However, the butterfly’s recent reappearance in the country is a result of climate change: The UK’s butterflies are migrating north, and the presence of the white-letter hairstreak is “almost certainly due to the warming climate,” according to Kirkland.
