Image
© Richard Crossen Guillemot colony.
Britain's sea birds are under threat, experts have warned, after an "unprecedented" 40,000 were found to have died in this year's storms.

Three times the average number of guillemots were killed on Skomer Island, Wales, one of the country's most important havens for seabirds, as they struggled to find enough to eat in turbulent seas.

Professor Tim Birkhead, of the University of Sheffield's Department of Animal and Plant Sciences, said that a "run of storms" and "high mortality" would mean seabird populations will start to decrease.

The warning comes after a spell of extreme weather from mid-December to early January that caused a succession of major winter storms, bringing widespread chaos to the UK.

The unpredictable weather continued earlier this month as Hurricane Bertha brought further rain and storms, with nearly the entire average rainfall for August falling in just the first half of the month.

The total number of birds found washed up along the coast between Portugal and Western Scotland due to the poor winter weather was around 40,000. Approximately half were puffins and the other half were guillemots.

Professor Birkenhead, speaking on BBC Radio 4's The Living World, said: "[The deaths] come about when the weather is bad, and either the fish flocks break up or the sea becomes turbulent and the birds can't see the fish so they can't get enough to eat.

"When you look at these dead birds on the beaches, they've got no breast muscle. They've starved to death.

"My fear is that this very unpredictable weather, with more and more storms, is going to get worse and worse and these birds can only withstand the occasional bad year. If we had a run of storms and high mortality, these populations would start to decrease."

Andre Farrar, of the RSPB, said the storms had compounded the problem of a declining seabird population due to a change in sea temperatures. Many British seabirds are now trying to move north to follow the colder waters.

"Every year there are storms and every year seabirds die at sea," he said. "But usually the numbers are recovered in the following breeding season.

"But the compounding factor at the moment is we're seeing some long-term changes to our breeding seabird populations, because their food supply is affected by sea temperatures which are in turn affected by climate change.

"So when you start to overlay storm impacts on these longer term declines, you start to get into more worrying situations."

He said it was too early to say how many birds had died as a result of Hurricane Bertha, but the storms would likely have killed significant numbers . "It's been an unprecedented year in terms of the weather we've had the numbers of birds found dead," he said.

In the early decades of the 20th Century there were 100,000 guillemots on Skomer but numbers plummeted to just 2,000 in the 1970s, most likely due to oil pollution in the sea. Numbers have slowly been recovering in recent years until the onset of storms.