New York, Dec 13 (IANS): At around 66-year-old, the world's oldest known seabird is expecting, again.

The Laysan albatross called Wisdom is incubating an egg at the same nesting the seabird and her mate use each year, Xinhua news agency quoted Amy Olliffe, an official with the Midway Atoll National Wildlife Refuge in the Hawaiian archipelago, as saying on Monday.

The refuge's oldest resident is also the world's oldest known breeding bird in the wild, Olliffe said.

Wisdom, spotted by biologists earlier this month, has successfully raised and fledged at least nine chicks since 2006. She has travelled an estimated three million miles in her lifetime.

Laysan albatross do not lay eggs every year and when they do they raise only one chick at a time, the contribution of even one bird to the population makes a difference, biologists said.

Midway Atoll is home to the world's largest colony of albatross. Nearly 70 per cent of the world's Laysan Albatross and almost 40 per cent of Black-footed Albatross as well as endangered Short-tailed Albatross all rely on the Refuge.

Albatross start to arrive to return from sea to breed in late October and by the end of November nearly every available nesting space on the atoll is claimed by a breeding pair.

There are 20 different birds species that rely on Midway Atoll, in addition to the over one million albatross. In total, over three million individual birds call the refuge home.