http://news.independent.co.uk/uk/environment/story.jsp?story=477921
Britain's birds are living longer, healthier lives
By Severin Carrell
04 January 2004
Many of Britain's birds are living for more than 30 years - far longer
than was previously thought, ornithologists have discovered.
Some birds caught last year have been alive for a third longer than
expected for their species. And others, still alive, may have hatched
before the system of putting rings on birds' legs began in 1909.
Experts think the spate of record-breaking last year is largely due to
better rings, but climate change could also be stretching birds' life
spans.
An oystercatcher, one of Britain's most familiar waders, has been found
aged 35, older than the seven supporters of the British Trust for
Ornithology who caught it in Lincolnshire last summer.
A whooper swan, a winter visitor from Iceland, was caught near
Caerlaverock in south-west Scotland aged 22 years and six months -
smashing the whooper longevity record by seven years.
And a Leach's petrel has been found in the Western Isles almost 30
years after it was first ringed, making it almost eight years older
than the oldest petrel previously found. It will have flown at least
330,000 miles on its migration from southern Africa in those years -
not counting the miles it flies while fishing each day.
The new records were uncovered during the trust's annual ringing
survey, when 1,730 ornithologists and volunteers trapped nearly 800,000
birds to record the data carried on their leg rings.
Several records for individual species were broken this year. In
Scotland, a buzzard, Britain's most common hawk, was found to have
lived for 24 years and three months, a modest increase in the previous
record of 22 years and six months.
A bar-tailed godwit was found aged 30 years and three months - a
four-year jump on the last figure. Cuckoos, the trust found, could live
for at least seven years - another four-year increase on the earlier
record. Skylarks can survive to nine years old, and house martins to
seven years.
The findings have confirmed the suspicion that many common birds live
longer than we realise. Experts believe that seabirds such as the
gannet could live to be 100. Some Manx shearwaters ringed in 1953 are
still alive.
The new records were mainly down to the more durable rings attached to
birds' legs, which are less likely to fall off, said Graham Appleton, a
press officer at the trust. Ringing is also better organised, so ringed
birds are more likely to be found and any worn-out rings replaced.
The work is crucial, he said, to understanding why birds such as the
house sparrow and starling are in such steep decline. "We've now got
much better estimates of the survival rates of birds, and that's
important because we need to know how long the average bird survives to
know whether their numbers are going up or down," he said.
However, Britain's milder climate in recent years will also improve a
bird's chances of survival, the trust suspects. Warmer winters and
longer summers will lower the chances that migratory birds, such as
whooper swan, petrel and oystercatcher, are killed by storms or the
cold.
Birding-Aus is on the Web at
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