Swallows have arrived in Britain. But don't even think about summer

More than 2,000 years ago, Aristotle observed: "One swallow does not make spring, nor does one fine day." Nevertheless, one could be forgiven for thinking the season was upon us.

Unprecedented numbers of swallows have been spotted across southern England - more than six weeks ahead of their normal arrival time.

It is thought the current erratic weather patterns are responsible for the early appearances, which were recorded in areas including Somerset and the Isles of Scilly. Ironically, the sightings coincided with temperatures falling nationally as cold winds swept in from the Arctic.

Graham Madge of the Royal Society for the Protection of Birds saidthe birds' arrival was brought on by mild air from the south-west a few days earlier.

Mr Madge said yesterday: "Normally it's April before most people see their first swallow or house martin. Even sightings in late March are unusual and normally house martins migrating from tropical Africa do not appear even in southern Spain until late February. These birds must have been in the vanguard of the early spring movement.

"Early migrants inevitably gamble with their lives and this is particularly so with swallows and house martins. Because of the current cold weather, these birds are clearly going to struggle to survive."

He added that the appearance heralded more change, saying: "We have long been warned that weather extremes would be a feature of ... climate change. It certainly seems to be turning out that way"