Disaster looms for seabirds after poor breeding season

SOME colonies of seabirds in the Northern Isles have had their worst breeding season on record, it has emerged.

On the Shetland island of Mousa, the 700 Arctic terns which arrived on the colony at the start of the breeding season failed to produce a single chick, according to a report by RSPB Scotland.

And a similar poor breeding season was also recorded on the RSPB's North Hill reserve on Orkney, where only 356 Arctic tern pairs returned to a site that once held more than 6,000 birds in the early 1990s. It was the worst breeding season at the reserve since records began in 1996.

The wildlife charity has also disclosed that only two kitti-wakes returned to the North Hill reserve to breed, without a single chick being fledged. And a survey of great skuas on Orkney has also shown that nearly a quarter of the pairs present at the beginning of the decade have disappeared - a decline that represents 3 per cent of the global population of the species

Rory Crawford, seabird policy officer for RSPB Scotland, said many seabird colonies in the Northern Isles had suffered badly in what had been a year of mixed fortunes for populations around Britain's coastline.

He said the changes appeared to be linked to the effects of global warming and a 70 per cent decline in the total mass of zooplankton reported in the north-east Atlantic since the 1960s. The fall in zooplankton has led to a corresponding decline in the number of sand eels, the staple diet of several seabird species.

Mr Crawford said: "The seas are getting warmer faster, it seems. Normally in the spring there is a big bloom of plankton, but the evidence suggests that is happening earlier in the year, when the chicks are not being fledged."

He added: "Arctic terns can live for over 30 years and their strategy is that they can have few bad years in which to raise their young. But Arctic terns on Orkney have had several bad years in a row, with very poor numbers of young being raised, and that is going to have an impact on the overall population.

"Kittiwakes are vulnerable as well, because like Arctic terns, they feed in the upper reaches of the sea and are very reliant on sand eels, whereas birds like guillemots and puffins and gannets can dive deeper and switch prey and go for things like sprats."

According to RSPB research, gannets in particular have enjoyed a good breeding season across Britain, with a colony at Bempton Cliffs in Yorkshire expanding to more than 8,000 pairs.