Birds living longer and flying further

It appears that birds really are living longer and travelling further than scientists had previously thought.

An international study by leading ornithologists has forced the radical revision of the life expectancy of several species, after birds - some wearing tags fitted more than 30 years ago - were discovered living well beyond previously recorded ages.

Staff at the British Trust for Ornithology have been exchanging details with colleagues and birdwatchers around the world to compile their latest report into the habits of a variety of species, all of which have been fitted with ring tags to help trace their movements.

As a result, years have been added to the assumed life expectancy of several species and a much greater understanding has been reached as to how far many birds travel.

One barnacle goose at Caerlaverock reserve on the Solway Firth, near Dumfries, south-west Scotland, was found to still be wearing a ring fitted to its leg 27 years earlier, making it at least two and a half years older than the previous highest age recorded for that species.

Taking into account annual spring and autumn migrations between the Solway and its breeding grounds on the Svalbard Islands, midway between northern Norway and the North Pole, scientists calculate that the bird has covered at least 240,000km during its life.

Scientists also discovered a tufted duck which was shot in Russia's Salavatskiy district 22 years after being ringed when just a few months old in Lincolnshire, 3500km away.

The previous record for the species was 17 years, nine months and 24 days.

The new records are the result of an international effort to tag and trace an ever greater volume of birds.

In 2004 volunteers caught and ringed more than in any other year since tagging started in Britain in 1909.

BTO volunteers put rings on 881,920 adults and nestlings in 2004, beating the previous record of 859,252, which was set in 1995.

In addition to recording the longevity of birds such as a 36-year-old oystercatcher, ringed in Norfolk in 1968, and a razorbill, ringed in 1962 at Gwynedd, scientists also investigated which bird species travelled the furthest.

Among the most travelled birds was a storm petrel which travelled 9,489km in its winter migrations after being ringed in Yell Sound, Shetland, on July 19, 1982 and caught at sea off Namibia's coast on February 24, 2004.

In addition they found a common tern, ringed on Seal Sands, Teesmouth in 2003, and found in Lambert's Bay, South Africa, in June 2004, had flown 9817km.

Although smaller woodland birds are shorter-lived their longevity also appears to be extending after a starling was found dead in Novgorod, Russia, more than 17 years after being ringed as a youngster in Suffolk - 16 months more than the previous record.

"Producing the Ringing Report is always exciting - but to break so many records in one year is tremendous," said Jacquie Clark, who heads the BTO Ringing Scheme.

"Unlike humans, birds don't spend a long time going through middle and old age. After maturing, they remain in good shape for most of the rest of their lives."

Ms Clark said that it was only once birds fell belowbelow par physically that they tended not to last long, losing the essential bit of speed necessary to escape predators.

Long migrations also increasingly sapped energy, while cold winters had more serious consequences.

"While in peak form they keep going," said Ms Clark. "In the case of seabirds, we've already reported a Manx shearwater that's in its 50s and the 42-year-old razorbill, both still returning to their Welsh colonies to nest.

"Oystercatchers, one of our largest waders, are another example. The longest known time between one being ringed and found has just passed 36 years - the bird in question could now be into its 40s."

Ms Clark said that the ringing of birds was providing a wealth of new information on how bird migration patterns are changing even though, on average, less than one out of every 50 birds ringed is subsequently reported to the BTO.

I should also like to thank the thousands of people each year who contact the BTO to tell us about ringed birds they find," said Ms Clark.

- INDEPENDENT