Hot summer helps butterfly numbers

Small tortoiseshell
Image caption Small tortoiseshells made a welcome resurgence

UK butterfly numbers have benefitted from the long spells of warm weather this summer, according to a nationwide survey.

The annual Big Butterfly Count attracted a record 46,000 participants who spotted a total of 830,000 insects.

The small white was at the top of the list of sightings, followed by the large white and the peacock.

Conservationists described the results as a relief following the washout summer of 2012.

The survey, organised by charity Butterfly Conservation, invited the public to count how many of 21 common species they can see in a 15 minute period and ran from 20 July to 11 August.

The sustained warm weather over the summer provided "perfect" conditions for a boom in butterflies and day-flying moths according to experts.

"Put simply, butterflies are cold-blooded creatures that rely on the warmth of the sun in order to be active," said Butterfly Conservation's survey manager Richard Fox.

"The hot summer this year meant that some butterfly species, which were in their early life cycle stages when the heatwave began were able to capitalise on it giving rise to high numbers of adults during the count in late July and early August."

Flying in the face of recent worrying declines, sightings of small tortoiseshells and peacocks rose by a staggering 388% and 3,500% respectively on 2012 figures.

The warm weather also saw an abundance of migrants from the Continent including the clouded yellow, painted lady and silver Y moth.

Experts in the flying insects were treated to a rare visitor when the long-tailed blue flew over to the south coast of England, from Devon to Suffolk, during August.

Fifteen of the species in the Big Butterfly Count showed increased numbers, 12 of which were up by more than 50%.

Only four species had decreased sightings: the ringlet, marbled white, meadow brown and six-spot burnet moth.

Mr Fox commented that the life cycles of these butterflies could offer an explanation for their low numbers.

"Each of those four species have a single generation each year, so the meadow brown, ringlet and marbled white butterflies and six-spot burnet moths that were counted this summer were the direct offspring of the ones that were counted last summer," he said.

"Although the numbers of these 'parents' were high last year, their breeding success may have been poor because of the bad weather."

Although conservationists are positive about the survey results this year they warn that "the weather will not solve the problem for us".

"UK butterflies are in long-term decline. Long-term studies going back to the 1970s show that three quarters of UK butterfly species have declined in range and many have also decreased in abundance," said Mr Fox.

"The only way that we will be able to halt and reverse the long-term declines of these beautiful creatures is by redressing the damage that has been done to wildlife habitats across the UK landscape."

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