Swallow numbers falling 'drastically'

Migrating swallows, which are threatened by changes in climate and environment, are returning to our countryside in drastically declining numbers, a study has revealed.

Every spring, hundreds of thousands of swallows make the arduous 6000km journey from South Africa to the British Isles, where they once found ample food and nesting space to rear their young.

About one million swallows were expected to return to our shores this year, but a survey by the Thetford-based British Trust for Ornithology (BTO) reveals that only about a quarter of that number have arrived so far.

Ornithologists at the BTO believe that bad weather could have affected the migration, but they are also concerned that changing conditions in Britain could be putting the birds off.

BTO spokesman Graham Appleton said: "About a quarter of a million swallows have got back so far and we think that weather could have caused them problems en route – it appears that they have had some difficulties.

"But there are other problems.

"This region used to be a key breeding area for swallows but changes in farming mean now there are less large insects for them to eat.

"If I was driving 20 years ago, I'd get loads of insects and flies splattering on the windscreen but, for various reasons, you see that much less now. There are not so many cattle and that means less insects.

"There are also far fewer nesting spaces, particularly in the east.

"Swallows like open access areas inside buildings such as barns or garages.

"But many barns have been converted into desirable residences and others are now sealed for farm hygiene reasons so there are fewer places for them to nest when they do return."

He said eastern England had already seen a 20pc drop in swallow population in recent years and warned that these figures could be a sign of serious decline.

"Swallows are very susceptible to changes in the climate. They travel across the Sahara every year and if it continues to get wider that could have a big effect on the numbers that survive migration," he said.

"More stormy weather is also predicted during spring and autumn and that will have a major effect on all migratory birds.

"These figures could bounce back if the swallows had a particularly good breeding season, but we don't know for sure what will happen. That is why we're interested in studying them and finding out more."

The new figures have been produced by hundreds of volunteers logging swallow sightings as part of the BTO's Migration Watch survey.

"We are running surveys this summer and next to work out whether swallows are breeding more successfully in some parts of the country than they are in others," explained Mr Appleton.

"We want people to tell us how many young swallows are reared successfully across the country."

He said people could help to encourage successful swallow populations by ensuring they had places for them to nest such as open porches, garages and sheds.