One Laysan albatross is brazenly defying the norms for her species. Wisdom, the world's oldest known wild bird, has returned to home port and laid an egg - at the magnificent age of 67 years old.

It's a feat that gets more impressive every year she does it - because the lifespan of Laysan albatrosses is around 50 years.

"It's just unprecedented that we have a bird that we know of that's 67 years old and still reproducing," Kate Toniolo, of the marine national monument Wisdom calls home, told National Geographic.

"It makes you wonder - could there be a bird two nests away from Wisdom that's even older?"

Wisdom was first given an identification tag in 1956, by ornithologist Chandler Robbins, who estimated her age to be around 6 years at that time. However, the age of birds is difficult to estimate unless they are very young, since they don't go grey.

We know that she had to have been at least five years of age in 1956, based on her adult plumage, but she could have been older -  so it's possible that Wisdom is even older than 67 now.

Wisdom wasn't seen again until 2002 - when Robbins found her again, and re-tagged her. She's been making regular appearances ever since.

Every year, Wisdom returns along with millions of other albatrosses to their nesting grounds at Papahānaumokuākea Marine National Monument on Midway Atoll. She's easy to spot - she always returns to the same nest site, and she has successfully hatched a chick every year since 2006.

This year, US Fish and Wildlife Services spotted Wisdom and her mate, Akeakamai, in November, and confirmed in December that the birds were nesting an egg, taking turns caring for it while the other searches for food.

Akeakamai sitting egg wisdomAkeakamai minding the egg while Wisdom forages. (Jodie Spross/USFWS Volunteer)

Eggs take about 60-64 days to hatch, so the little one will probably make its way into the world by mid-February. It will then take around five months to fledge, or grow its adult feathers.

Albatrosses don't experience menopause (there are only two animals that do, humans and orcas), so it's perfectly normal for Wisdom to continue producing offspring, advanced age notwithstanding.

Laysan albatrosses also form life-long monogamous bonds with their mates, going into a year or two of mourning when one of the pair dies. Wisdom has outlived at least one mate that the US Fish and Wildlife Service knows of.

She's not the longest-lived bird. That honour goes either to the cockatoo Cookie, who died at his home in Chicago Zoo at the ripe old age of 83; or a blue macaw named Charlie, reportedly born in 1899 (although that report has never been verified).

But she may have the most air time under her wings - 3.2 to 4.8 million kilometres (2 to 3 million miles), according to an estimate by the US Geological Survey. And in her lifetime, she has hatched around 39 chicks.

Laysan Albatross numbers declined in the 1990s and early 2000s, but have since started to recover. However, they're still listed as Near Threatened on the IUCN Red List from human interference - plastic ingestion, lead poisoning, human disturbances and conflicts with aircraft.

So every chick counts.

"An albatross egg is important to the overall albatross population," said Bob Peyton, US Fish and Wildlife Service Project Leader for Midway Atoll Refuge and Memorial.

"If you consider that albatross don't always lay an egg each year and when they do they only raise one chick at a time - each egg is tremendously important in maintaining the survival of a colony."