Record-breaking sightings of vast flocks of little auks in Britain have prompted new concerns over the impact of climate change on the migration patterns of bird species.
The record for the size of flock has been broken twice in four days, according to the National Trust, with 18,000 of the tiny black-and-white seabirds recorded around the Farne Islands off Northumberland last week – 7,000 more than the previous record set off Flamborough Head, East Yorkshire, in 1995.
But even this vast gathering was dwarfed by the flock spotted there on Sunday when 29,000 little auks were seen.
Thousands of the birds were recorded battling last week's gales from watchpointss along the north-east coast but little auks have been seen as far south as East Sussex and Kent, hundreds of miles south of their normal territories.
The "mass displacement" of the flocks may show the unpredictable effects that climate change will have on wildlife with, in this case, a traditionally cold weather bird moving in to warmer climes, most likely in search of food. But they may simply have been blown off course by the gales that caused last week's tidal surge off East Anglia.
However, as other species of seabird such as guillemot and terns begin to show catastrophic reductions in their number of young, it is feared that subtle changes to the ecology of the world's oceans could be behind the mass sightings.
"People are really surprised by these sightings though they are becoming more common and we don't know why. No one really understands much about their breeding habits because they breed so far to the north," said Mark Grantham of the British Trust for Ornithology. "But all our other seabird species are suffering really badly and that is because of subtle changes in acidification and rising temperatures in the North Sea."
Little auks, relatives of the puffin, are one of the smallest seabirds, around the size of a starling, and feed on small crustaceans, fry and plankton rather than fish. Changes at the bottom of the food chain can have profound effects on larger species.
The growing presence of little auks in the UK has brought them into conflict with other birds. Flocks spotted over the weekend, some of which had not fed for four days, were badly weakened as they fought the northerly winds to head back up the east coast. Birdwatchers reported that many of those that dropped to the sea to rest were seized and swallowed whole by gulls.
Meanwhile, it is feared that the recent storms may have washed away hundreds of grey seal pups from one of Britain's most important colonies. Waves battered the Farne Islands last week, and scientists are assessing the impact on the pups. Television viewers were alerted to their plight after it was featured on the BBC's Autumnwatch on Tuesday.Reuse content