Britain's oldest known bird reaches age of 50 after flying five million miles

Ornithologists believe they have discovered the oldest wild bird in Britain: a small black-and-white Manx shearwater that has survived storms, rats and annual flights to South America to reach the age of 50.

Records at the national bird-ringing scheme indicate it has outlived other wild birds by almost a decade and flown more than five million miles.

The seabird, whose scientific name is Puffinus puffinus, was discovered in a colony of several thousand others on Bardsey, an island off the Lleyn peninsula in north Wales.

Although Manx shearwaters, which spend much of their time flying over the sea, are renowned for their longevity, the age of the Bardsey bird has amazed experts.

Chris Mead, a leading ornithologist, said: "Most wild birds live short lives before falling prey to a car or the family cat. But some seabirds can live for a very long time – and this is one amazing case in point."

Mr Mead, a consultant to the British Trust for Ornithology, added: "For such a small animal the length of its life is amazing. The oldest bird on record was a sulphur-crested cockatoo in London Zoo, which reached more than 80. Clearly it benefited from a sheltered life – but these old birds have had to battle against storm and tempest all their life."

The Bardsey bird, whose sex is not known, is also a prolific traveller, the ornithologists say. It has clocked up 500,000 miles, the equivalent of a return trip to the Moon, during winter migration to Brazil, Argentina and Uruguay. Taking feeding flights into account, it has probably covered a total of five million miles.

"I don't know which impresses me most, its extraordinary longevity or the fantastic distance it has travelled," Mr Mead said.

The bird has been ringed four times: in 1957, 1961, 1977, and earlier this month. It was estimated to be about five years old when it was ringed for the first time.

The Manx shearwater is one of the tube-nosed group of birds, including the albatross and fulmar, which tend to outlive other wild varieties because of a gland in their sinuses designed to purge salt water. The previous oldest known wild bird in Britain was also a Manx shearwater, recorded in 1996 in Northern Ireland aged 41.

Britain has 90 per cent of the world's population of Manx shearwaters with about 235,000 pairs, mostly in Scotland and Wales. The population is growing slowly thanks to improved adult survival. But they remain vulnerable to rats, because they nest in burrows. The infestation of islands by vermin has in the past caused local extinction of the breed.