After an absence of 133 years, the rare white-letter hairstreak butterfly has once again been found living in Scotland. The endangered butterfly species has been discovered living in a field just 100 yards from the English border. It’s the first time since 1884 the white-letter hairstreak has been spotted in Scotland.
A single white-letter hairstreak was seen and photographed earlier this month by Iain Crowe of the UK’s Butterfly Conservation. Crowe described the butterfly as “ragged and worn.” Nevertheless, the species was back in Scotland after more than a century-long absence.
“It is not every day that something as special as this is found when out and about on a regular butterfly foray,” says Crowe.
Scientists suspect that climate change may be the reason why the white-letter hairstreak has migrated north into Scotland. While typically bad for the earth, warmer temperatures via climate change have once again made Scotland a viable habitat for the rare butterfly species.
“Climate change is a double-edged sword but it’s an exciting time to be in the Scottish borders,” explains Paul Kirkland of Butterfly Conservation Scotland. “It’s not just butterflies but moths and dragonflies are moving north quite quickly.”
White-letter hairstreak caterpillars subsist off of British elm trees. But an outbreak of Dutch elm disease first document in the 1970s was disastrous for the population of white-letter hairstreak butterflies in the UK.
It’s estimated that 96% of the species was wiped out by the epidemic over the last 40 years. But now there are signs that it’s making a comeback.
The next question is whether the butterfly Crowe spotted was a one-time occurrence or evidence that the white-letter hairstreak has set up a breeding colony within Scotland.
Kirkland warns that Dutch elm disease remains prevalent in Scotland, so butterfly enthusiasts may not want to get their hopes up. However, he adds that there may be enough Wych elm in Scotland to help the white-letter hairstreak “prosper and spread.”
Regardless of the reasons why its back or its future prospects, just knowing that at least one white-letter hairstreak made its way into Scotland for the first time in 133 years is exciting news for lepidopterists throughout the UK.