This season is on course to be the best summer for butterflies since 2006, according to conservationists.

This will come as welcome news to wildlife experts in Suffolk, who fear that some species of butterfly could soon be wiped out from from the county’s countryside, due to changing grassland and meadow habitats.

Suffolk is currently in the throes of the Big Butterfly Count – a nationwide survey aimed at helping to assess the health of Britain’s environment.

The 2013 count, which ends this Saturday, is the world’s biggest survey of butterflies. Almost 27,000 people took part last year, counting 223,000 individual butterflies and day-flying moths across the UK.

Liam Creedon, spokesman for Butterfly Conservation, the organisation behind the survey, said: “Last year after a terrible spring, we suffered the wettest summer for more than 100 years. As well as the rain, temperatures and sunshine levels were well below average. Butterflies need warm weather to feed, fly around and find mates. If it’s wet like it was last summer, then this has a significant knock-on effect on butterfly numbers.”

As a result, many common species were much less abundant last summer, with almost three quarters of species showing year on year declines.

The number of Common Blues decreased by half for the second year running, brimstone numbers were down 53% and numbers of speckled wood and red admiral, both of which had done well in the summer of 2011, fell back sharply, with numbers dropping by 65% and 72% respectively on the previous year.

But Mr Creedon said the recent long spell of warm weather has had a positive impact on butterly numbers. He added: “The tortoiseshell was once a very common butterfly, but numbers have gone off a cliff in recent years and this has given us great cause for concern.

“Numbers have picked up right across the board this year according to figures that have come in so far, and that’s extremely encouraging.”

Suffolk conservation volunteer George Millins added: “I recorded 13 Common Blues in one location in Sudbury last week, which is a significant improvement. Anyone wanting to encourage butterflies can take simple measures like growing nectar plants including lavender, apple mint and buddleia in their gardens.”