Butterfly tour of Britain documents species at risk

Once they were a common sight in the wild meadows and hedgerows of Britain but as the modern world continues to encroach on the countryside, many species of butterfly have become almost extinct.

It is six years since the Millennium Atlas of Butterflies in Britain and Ireland concluded that widespread habitat loss and changes in land use had pushed many of them to the brink.

In an attempt to get a snapshot of the plight of the butterflies, Mark Stratton, a writer, spent five months and travelled more than 8,500 miles to record each one of the country's 59 indigenous species in their natural habitats.

From the Glanville fritillary clinging to survival in a dozen colonies on the southern slopes of the Isle of Wight to the chequered skippers on the slopes of Ben Nevis in the company of golden eagles, the conservationist completed what he hopes will not be the last tour of Britain's endangered butterfly sites.

"It was quite an assignment and took a lot longer than I thought it would," said Mr Stratton, a former countryside ranger who embarked on the trip for an article for BBC Wildlife magazine.

Between the beginning of April and the end of August last year he travelled from one end of the country to the other, crawling on his hands and knees through coarse tussocks of mat grass, clambering up mountain sides, wading through dense woodland and strolling over meadows in his search for Britain's increasingly elusive butterflies.

"On the face of it there are 59 native species of British butterflies, which doesn't sound a lot compared with 400 in places like Portugal, but it was a lot tougher project than I imagined it would be."

The numbers of the Glanville, which is thought to have been brought to Britain by French PoWs from the Napoleonic wars in grass-stuffed mattresses, have remained stable thanks to abundance of their larval food plant, ribwort plantain, on the chalk cliffs of the Isle of Wight.

However, the same cannot be said for many other species such as the brown fritillary, whose numbers have declined by about 80 per cent in the past 25 years.

"There is no room for complacency; we can't take their survival for granted," Mr Stratton said, adding that his own observations, together with discussions he had with Dr Martin Warren, the chief executive of Butterfly Conservation, convinced him that Britain's butterflies were faring worse than thought.

Recent research suggests seven out of every 10 species are declining, while 15 of Britain's rarer butterflies are in real danger. Even common species, such as the wall brown and grayling, are disappearing.

"There has been a decline in all species as they are continually pushed back as their habitats are encroached upon by creeping urbanisation and agricultural intensification," Mr Stratton said. "Butterflies ... have been pushed into isolated little pockets of perfect habitat that suits their requirements.

"If action isn't taken it is going to become even harder to find these butterflies. As it is, the vast majority of people will never see them, unless they are willing to go to these out-of-the-way areas and look for them."

Six that face extinction

ADONIS BLUE

Now a rare species in the UK, it is confined to just a few hot areas in southern UK where the grass is very short (often cropped by rabbits) and Horseshoe Vetch grows.

MARSH FRITILLARY

Britain's most heavily protected native species was found in a Wiltshire field. Its favourite habitat tends to be marshy ground or sunny hillsides.

GREEN HAIRSTREAK

Although not scarce, the species has been declining in many areas where it used to be a common sight. It often survives at low population levels at individual warm, sheltered areas of grassland and scrub.

SILVER-WASHED FRITILLARY

A Species of Conservation Concern in Britain because of changes in woodland management in recent years, this once common species used to be widespread across England and Wales but is now found only in southern and south-western England.

CHEQUERED SKIPPER

The mysterious chequered skipper - nobody is sure why it retreated from England during the 20th century to western Scotland - is sur-viving well among the bog myrtle slopes around Ben Nevis and in remote uncut damp grassland where its food plant, purple moor-grass grows, particularly on the edges of open broad-leaved woodland.

SWALLOWTAIL

The UK's largest butterfly, the swallowtail, is widespread in mainland Europe but is restricted to the Norfolk Broads in Britain.