Oldest known seabird lays an egg at 66

PIC: The world's oldest known banded bird in the wild is with her mate. (AFP)

The world's oldest known seabird is expecting, officials at the Midway Atoll National Wildlife Refuge have said.

The Laysan albatross known as Wisdom -- a bird thought to be at least 66 years old -- is incubating an egg once again, putting her on track to become the oldest breeding wild bird in the world.

Charlie Pelizza, the US Fish and Wildlife Service project leader at the refuge in the middle of the North Pacific Ocean,  said in a statement that Wisdom has been returning there for six decades.

"The staff was abuzz with the news that Wisdom was back and incubating," he said.

The bird was first banded in 1956. Since 2006 she has fledged at least nine chicks, and traveled some three million miles over the course of her life.

Her mate, Akeakamai, was seen near their nest site on November 23.

The Midway Atoll National Wildlife Reserve is home to the world's largest albatross colony.

Park staff had thought Wisdom might take a year off from breeding, as many albatrosses must take time to molt and replenish their plumage.

The birds spend almost 90 percent of their lives flying, traveling thousands of miles every year looking for food.

There's an estimated 3 million breeding birds year-round at the Midway Atoll refuge.