A BIRD expert from The University of Sheffield has spent 40 years studying seabirds on an island off the UK in one of the longest running investigations of its kind.
Professor Tim Birkhead, aged 62, of the university’s Department of Animal and Plant Sciences, first visited Skomer Island off the cost of west Wales as a 22-year-old in 1972.
Since then he has returned every summer, gaining invaluable information about guillemots.
He is currently on the island again, marking his 40th season studying the guillemots, conducting an annual census and ringing the birds to see how old they are when they start to breed and how long they live.
Prof Birkhead said: “It has been an invaluable investigation. For example, it is clear climate change has had a huge effect on the guillemots as they now breed two weeks earlier than they did in the 1970s.
“We also know a huge amount more about guillemot biology than we did 40 years ago, and we can use changes in guillemot numbers to tell us what is happening in the seas surrounding the island.
“Long-term studies like this are few and far between but remain vital for understanding changes taking place in the environment. It’s been a constant challenge both to secure funding and to carry out the work itself as the birds breed on the sea battered cliffs of a remote island.”
Technological advances throughout the four decades have enabled Prof Birkhead to gain even more information about the birds.
“Using new tracking technologies, like GPS and geolocators, we now have a very complete picture of where guillemots go to forage,” he said.
“During the breeding season they forage within about 60km of Skomer in the south Irish Sea, but in winter they travel huge distances, moving between the Bay of Biscay and the far north of Scotland.”
In 1972 when Prof Birkhead began his studies the guillemot population breeding on Skomer was just 2,000 individuals. Yet pictures of the island 30 years earlier showed there were around 100,000 guillemots then.
In 2011 numbers were up to 20,000 individuals.