Mystery of tumbling puffin population

Michael McCarthy, The Independent 26 Jul 08;

Numbers of puffins at England's largest colony, on the Farne Islands off the Northumberland coast, have mysteriously tumbled by a third in the past five years.

Breeding pairs of the small seabirds have decreased on the National Trust-owned islands from 55,674 in 2003 to 36,500 this year.

Results of the count, which was carried out by the team of nine National Trust wardens across eight of the islands, came as a shock. All eight islands showed a decrease in population, with four showing a dramatic decrease of up to 50 per cent.

"The results from this survey have completely surprised us, as we were predicting another rise in the numbers of breeding pairs," said the head warden, David Steel. "Stocks of sand eels, the staple food of puffins in the summer, are in good supply around the islands and there is a lack of ground predators, creating a good environment for puffins to breed."

He added: "Extensive monitoring work shows that good numbers of young puffins are successfully fledging each year but it would appear they're just not coming back to the islands the following years. Presumably fewer birds are surviving over winter than are needed to maintain current numbers."

Staple Island and Brownsman Island, where the majority of puffins can be found, have seen the numbers of breeding pairs fall by more than 30 per cent since the last survey was carried out in 2003.

Possible factors behind the decline are not yet properly understood but according to the trust, "this dramatic drop in numbers would suggest there is something happening at sea during the winter, for example, an intensification of storms as a result of our changing climate which could affect the ability of puffins to find food."

John Walton, the trust's property manager for the Farne Islands and the Northumberland coast, said that in almost 30 years of working with the Farne puffins this was the first downturn in the population he had witnessed. "With such a dramatic fall in numbers of breeding puffins on the islands, we need to do some further work to find out why things are changing, and whether this is a long term trend," he said. "We'll being carrying out sample surveys next year on some of the islands to build up a more detailed picture of what is happening."

Records for the number of breeding pairs of puffins found on the Farne Islands date back to the 1930s, but the first detailed count took place in 1969 when there were 6,800 pairs. The islands hold the largest colony of puffins in England, and constitute the fourth largest colony in the UK.

Puffins nest underground in burrows, and during the survey, which began in May, the wardens put their arms down holes to make sure the nests were occupied.

The islands are home to many seabirds as well as a population of grey seals.

Unexpected fall in puffin numbers
Mark Kinver, BBC News 25 Jul 08;

England's biggest colony of puffins has seen the birds' numbers fall by a third in just five years, a survey shows.

Experts had expected to see a slight increase in the population on the Farne Islands, owned by the National Trust.

The Trust says the size of the decline is unprecedented, adding that it will carry out another survey in 2008 in order to monitor the situation.

One theory is that many of the birds are dying from starvation during the eight months they spend at sea.

"We were expecting a slight increase because since the last survey in 2003, we had a number of good years for puffins," explained David Steel, the Trust's head warden on the islands.

"There were plenty of chicks fledging from the nests, so we were not only getting enough to maintain the population, but increase it.

"But something is going badly wrong somewhere."

Winter losses

The three-month survey, carried out on eight of the islands, recorded 36,500 breeding pairs. The previous survey, which was conducted in 2003, counted 55,674 pairs.

Mr Steel told BBC News that there was no visible explanation for the decline on the islands.

"There was no evidence that they were having difficulties.

"The birds had been bringing in good quantities of food, and there was not a predator problem on the islands."

One suggestion for the downturn is the survival rate over the winter months, when the puffins spend eight months at sea.

"The dramatic decline on the Farnes leaves no doubt that the North Sea has lost a substantial number of its puffins," explained Professor Mike Harris, emeritus fellow at the Centre for Ecology and Hydrology.

"With poor survival of adult birds a likely factor in the decline, we urgently need to know more about puffins during the eight months of the year that they spend in the open sea."

The results reflect the findings of an earlier survey on the Isle of May, in the Firth of Forth - the UK's largest puffin colony. Published in June, it also showed a decline of about 30%.

David Steel said this year's results had left his team feeling anxious about the puffin population on the Farne Islands.

"This colony is the fourth largest in Britain, so to see it experience such a decline is a worry."

In order to monitor the situation, Mr Steel said the Trust would carry out another survey next year.

"We are going to target the islands that saw the biggest decreases," he explained.

Puffins nest in burrows, so their numbers are assessed by counting the number of occupied burrows, after the birds have cleaned out their nests and before vegetation begins to grow over.

Mr Steel explained: "We can then compare them with this year's results because we actually have 20 square metres on each island mapped, so we can go back to a particular spot and see what the impact is next year.

"Hopefully, we can now judge it on an annual basis and keep a much closer eye on things."