Britain’s butterflies were on the wing earlier than ever before this spring following a warm April, a wildlife charity has said.
Some of the country’s rarest butterflies are among those which have been breaking records with the dates they emerged this year, according to Butterfly Conservation.
The endangered Lulworth Skipper was seen seven weeks before the time it normally emerges, while the Black Hairstreak, one of Britain’s rarest butterflies, was on the wing more than a week earlier than it has ever been recorded.
The chocolate-coloured Black Hairstreak, found at just a handful of sites in the East Midlands, usually emerges in late June, but was first recorded on May 24 this year.
And the widespread Small Copper butterfly, which typically emerges in the first week of May, was first seen on March 9.
Butterfly Conservation said Britain’s butterflies appeared to have been emerging increasingly early in the year over recent decades, and the charity has been doing more detailed monitoring of the insects’ appearances in the last 10 years.
The conservation experts believe the long-term trend is being driven by climate change, and has been accelerated this year by an exceptionally warm and sunny April.
Tom Brereton, head of monitoring at Butterfly Conservation, said that in addition to the first butterflies being spotted earlier in recent years, numbers were also peaking earlier as the whole life cycle shifted forward in the year.
Butterfly Conservation’s chief executive officer Martin Warren said: “2011 is breaking a lot of records for the earliest sightings of many butterflies.
“This is almost certainly to do with the very hot dry spring.
“Many of the butterflies we’ve already seen will be having second broods – which means there could be a profusion of butterflies in July and August.”
He added that Butterfly Conservation was hoping to get as many people as possible involved in its annual national Big Butterfly Count next month, which would help scientists determine exactly what is happening to Britain’s butterflies.