Butterfly effect: Why Britain is suddenly all of a flutter

Three sodden summers brought many butterflies to the brink of extinction. But now Britain's most endangered species are making a comeback thanks to 2010's Indian summer and conservation efforts.

Research from the Butterfly Conservation charity suggests the Adonis blue, wood white and the marsh fritillary have increased in numbers. The findings mark a success for conservation efforts such as the Great British Butterfly Hunt, The Independent's campaign, which drew the support of Sir David Attenborough.

Butterfly experts are cautiously optimistic that if Britain has a similar summer this year, some of the most threatened species could make a significant recovery after populations plummeted in recent years because of bad weather, habitat loss and intensive farming. Continuous or heavy rain makes its hard for butterflies to survive because the temperature is usually too low for them to fly.

The wood white is Britain's smallest butterfly and its numbers have fallen by 96 per cent since the Seventies. But last year suggested increases of 600 per cent, with the most sightings in Herefordshire, Buckinghamshire and across Ireland. The marsh fritillary, which has also been in decline, increased by 134 per cent and the Adonis blue by 74 per cent.

Dr Tom Brereton, head of monitoring at Butterfly Conservation, attributed the increase in "specialist" species to conservation. "There have been a lot of good efforts but the last few years haven't had the weather to go with it. It shows these projects are working, given time," he said. But despite the welcome signs of butterfly resurgence, conservationists warned there was still the problem of a longer-term fall in numbers – with three-quarters of the 58 species declining in recent decades, and nearly half seriously threatened. One of the UK's rarest butterflies, the Lulworth skipper, which is confined to the Dorset coast, had its worst year since 1976. Meadow browns, one of the country's most common species, also had its worst year on record, while Essex skippers and wall butterflies also fared poorly.

Five species of British butterfly have become extinct, including the large blue. Dr Marc Botham, butterfly ecologist at the Centre for Ecology and Hydrology, said: "Butterflies are highly sensitive to how our countryside is changing."

Adonis blue

The blue butterfly, is one of the most characteristic species of southern chalk downland, where it flies low over short-grazed turf. Males are blue, females brown with a row of red spots with blue edges on hindwing. Figures up 74%.

Duke of Burgundy

A small attractive insect, whose wings are a lattice of marmalade-orange and black. The insect was originally a coppiced woodland butterfly and lost much of its habitat with the decline in traditional woodland management and the growth of conifer plantations. Feeds on cowslips and primroses. Figures up 18%.

Black hairstreak

One of the most elusive butterflies, found only in thickets of blackthorn in a small part of the East Midlands of England. The adults spend nearly all their time in the canopies of trees or dense scrub, where they feed on honeydew secreted by aphids. Figures up 195%.

Wood white

A delicate species, that lives in woodland rides and has suffered from the decline in traditional woodland management. In Britain it has declined by more than 60 per cent over 30 years, but in the past decade has staged a comeback, with a recent increase of about 10 per cent. It has responded well to habitat management in Herefordshire, Shropshire and Warwickshire. Figures up 600%.