An albatross in her 60s has produced a new chick at a wildlife refuge on a tiny atoll in the north Pacific ocean, US government wildlife officials announced on Wednesday.

According to her banding records, she is the oldest known US wild bird ever documented – and she is evidently still fertile.

Wildlife officials spotted the bird – named Wisdom – a few weeks ago with a chick.

"To know that she can still successfully raise young at age 60-plus, that is beyond words," Bruce Peterjohn, the chief of the North American bird banding programme as the US geological survey wildlife refuge in Laurel Maryland said in a statement.

John Klavitter, the biologist who spotted Wisdom, said she had also nested in 2006, 2008, 2009 and 2010.

Wisdom produced her first known offspring in 1956 – which was when she was originally tagged by biologists from the USGS. They put her age at the time at a conservative eight or nine; albatross can mate as early as age five.

Since then, Wisdom has long ago outlived the average life span for an albatross. She has also worn out five sets of aluminium bands.

In that extended lifespan, government biologists estimated she had probably logged about 3m miles of flight – or the equivalent of six round trips to the moon.

And she has probably produced more than 30 to 35 mini-Wisdoms, officials said.

Albatross lay only one egg a year, and it takes about a year to raise a chick. After that, they typically take a year off.

Adult albatrosses mate for life, but it is not known whether Wisdom is still with her original partner, or if she has outlived him.