Long-haul flier: Bird that travels to moon and back three times

IT IS an epic journey that sees a 100-gram bird make the equivalent of three return trips to the Moon during its lifetime.

New research has confirmed that the Arctic tern flies about 50,000 miles each year, migrating all the way from one pole to the other.

It is thought to be the longest annual migration of any living creature.

The bird, which has a wingspan of about 30 inches, breeds in Greenland during the summer, and spends its winter holidays in Antarctica.

About 47,000 pairs of Arctic terns nest in Scotland during the summer – more than 80 per cent of the UK population.

During its 30-year life, the bird will fly a total of about 1.5 million miles.

Scientists fitted Arctic terns with tiny "geolocators", and were able to track the journeys of the birds for the first time.

They discovered that the birds did not fly without a break from Greenland to the Weddel Sea on the Antarctic shores.

Instead, they had a rest for almost a month at a previously unknown stop-over point in the Newfoundland Basin, possibly to stock up on food.

The birds, also known as sea swallows, then split into two groups just south of the Cape Verde Islands.

About half crossed the Atlantic to follow the Brazilian coast south, while the remainder tracked the west coast of Africa.

The report authors, writing in the journal Proceedings of the National Academy of Sciences, said: "As Arctic terns can live for more than 30 years, the total distance travelled in a lifetime may exceed 2.4 million km, equivalent to approximately three return journeys to the Moon."

Carsten Egevang, the lead author, from the Greenland Institute of Natural Resources, described the birds' migration as "phenomenal".

He said: "These birds travel breathtaking distances and travel thousands of miles every year.

"They are the ultimate biological machines built for long-distance travel … they are very graceful in the air and spend thousands of hours flying and drifting on the wind."

He added: "This is a mind-boggling achievement for a bird of just over 100 grams."

In recent years, colonies of Arctic terns have experienced catastrophic failures in the breeding season.

James Reynolds, spokesman for RSPB Scotland, said: "Arctic terns are possibly the ultimate migrant bird species, clocking up astonishing distances every year, and this research now reveals just how incredible that migratory journey is."

Mr Reynolds said the failure in recent years was believed to be due to a collapse in numbers of sand eels, their favourite food.