Mystery of albatross unravelled

The wandering albatross does not wander aimlessly, as Coleridge's The Rime of the Ancient Mariner suggests, but commutes determinedly between its breeding ground and a patch of open ocean thousands of miles away.

An experiment that tracked a group of albatrosses has shown that each bird returned to a home patch of ocean where it took a "sabbatical" year off from the trauma of raising a family.

The study also found that male and female albatrosses scrupulously avoid wandering into members of the opposite sex out of the breeding season by making sure that they fly many hundreds of kilometres apart.

The mystery of where the wandering albatross goes in its long and soulful journey over open sea has inspired sailors and writers alike, epitomised by Samuel Taylor Coleridge's poem.

Now the mystery has been solved by Henri Weimerskirch and Rory Wilson of the French National Scientific Research Centre in Beauvoir, using a tracking device attached to the legs of nine albatrosses.

It accurately measured the time of sunset and sunrise over many months, data which the scientists could use to determine the precise movement of the birds.

They found that each albatross, which has a wingspan of 1.8m and can glide for months on end, has a preferred feeding site over open ocean south of South Africa when it is not breeding on the Crozet islands, east of New Zealand.

The scientists say in a paper published in the journal Nature: "After spending a year covering an estimated 150,000km foraging around colonies to hatch and raise their single chick, wandering albatrosses take a year off ... but even with this new freedom, the birds confine their movements to a preferred sector."

Albatrosses can spend up to half their lives gliding over open ocean when they are not raising a chick. After breeding, pairs split up to go their separate ways.

"In each pair, the male spent the winter just north of the pack ice in Antarctic waters, whereas the female stayed south of Madagascar," the scientists say.

Knowing where albatrosses go in winter will help to throw light on what risks they face from the fishing industry, which unwittingly kills thousands of albatrosses which are trapped and drowned in baited long lines.

"Any plan to remedy this shocking loss will depend on establishing the extent of overlap in the areas used by both albatrosses and fisheries," the scientists say.

"Birds spending their sabbatical year in sectors where long-line fishers occur are at risk of being killed. [This] means that only those wintering in zones without fisheries will survive in the long term."