Swedish Bird 'Terns' up in Derby

Arctic Tern: Unusual Peregrine prey at an inland site (photo: Steve Round).

The remains of an Arctic Tern that had been ringed in Sweden were found on the roof of Derby Cathedral last week. They were found during a routine clean-up of the roof by Head Verger Tony Grantham and Derbyshire Wildlife Trust's Nick Brown. Along with other prey remains, the tern had been caught by the pair of Peregrine Falcons which nested on the tower directly above the roof.

Nick Brown, Derbyshire Wildlife Trust's Education Manager, said: "Finding a wild bird with a ring on its leg is an extremely rare event but to find that the ring was a Swedish one was even more exciting! The inscription read 4392757 Riksmuseum Stockholm."

Nick thinks that the tern was probably caught about the end of April or early May when a large group of Arctic Terns passed through the Trent Valley.

Nick said: "I contacted the Swedish bird ringing office who told me that this ring was put on the leg of an Arctic Tern chick on an island off southwest Sweden in June 2002. That makes the bird almost five years old. During this time, it will have migrated back and forth to and from the Antarctic five times, a journey of almost 100,000 miles - an extraordinary mileage! According to the British Trust for Ornithology, this is only the ninth record of a ringed Arctic Tern from Sweden in the UK since 1909."

Arctic Terns nest on the coast of northern England, Wales and Scotland as well as the Scandinavian coast. They normally migrate through the English Channel en route for Scandinavia, but if there are strong easterly winds, the birds can get pushed north and cross the UK mainland, passing over or stopping briefly at reservoirs and gravel pits.

Tony Grantham said: "Cleaning the drains and gullies on the roof has suddenly become a much more interesting job for us at the cathedral. The emerging story of the wide range of prey the Peregrines have been catching is fascinating."

Peregrine Falcon: Studies of remains at Derby Cathedral have revealed a number of unusual species as prey items (photo: Sean Gray).

So far the remains of 41 species of bird have been found at the cathedral since recording started in spring 2005. The list includes five species of duck, eleven waders, Quail, Water Rail, Little Grebe, Swift and Waxwing as well as more common species such as Starling, Blackbird and Magpie.

Nationally, over 100 species have been recorded. Peregrines take a wide spectrum of prey and by doing so do not seriously impinge on any one species. They also catch birds during the night, especially at times of migration.

Nick Brown said: "Floodlighting is used around the cathedral. This seems to draw night-migrating birds towards the city where they are easy prey for the falcons. Woodcock are commonly taken, especially in autumn when this species is moving south from Scandinavia and eastern Europe to spend the winter in the UK, France and Spain. Since Woodcock, and other birds such as Water Rails, Quail and Jack Snipe only fly at night, we can be sure that the falcons have developed a night-hunting technique which has also been reported from New York, Warsaw and other cities throughout the world which now have Peregrines nesting in them."

Read more on this story on the Derby Cathedral Peregrine Project - 2007 blog.