| Albatross astonishes scientists by producing chick at age of 62|
|She is described as awesome. And wonderful. And maybe a little weird. She is the world's oldest-known living wild bird at age 62, and she gave birth to a healthy chick that hatched on 3 February. It's pretty amazing that Wisdom, named by scientists who stuck a tag on her ankle years ago, has lived this long. The average Laysan albatross dies at less than half her age.|
Scientists thought that, like other birds, albatross females became infertile late in life and carried on without producing chicks. But Wisdom, who hatched the chick at the Midway Atoll National Wildlife Refuge in the Pacific Ocean, defies comparison. Her feat could prompt scientists to abandon some early theories about the birds.
Wisdom has raised chicks five times since 2006, and as many as 35 in her lifetime. Just as astonishing, she has likely flown up to 4.8m km since she was first tagged at the Midway Atoll at the end of the Hawaiian Island chain in 1956, according to scientists who have tracked her at the US Geological Survey. That's "four to six trips from the Earth to the moon and back again with plenty of miles to spare," the USGS said in an enthusiastic announcement last week.
"It blows us away that this is a 62-year-old bird and she keeps laying eggs and raising chicks," said Bruce Peterjohn, chief of the bird banding laboratory at the USGS Patuxent Wildlife Research Centre in Laurel. "We know that birds will eventually stop reproducing when they're too old," he said. "The assumption about albatrosses is it will happen to them, too. But we don't know where that line is. That, in and of itself, is pretty amazing."
Wisdom's advanced-age delivery not only could help scientists understand more about the albatross, but also more about the health of the oceans.
"These birds are emblematic of the health of the ocean and the health of that ecosystem," Peterjohn said. "It has to be healthy for them to live long."
But the USGS and other organisations that study albatrosses must first untangle some shortcomings in the research. Scientists say past methods of data collection have been a little shaky.
Thousands of Laysan and other species of albatross have been banded since 1956, when scientists started studying them at the atoll to determine why so many were striking Navy aircraft, killing the birds and damaging the machines.
The tracking bands generally fall off after 20 years, sometimes before being replaced. Wisdom went through six, which were replaced before she lost them. As far as Peterjohn and other scientists know, "half the birds could be 60 years old," he said. "These birds could be much older than we think."
Nineteen of 21 albatross species are threatened with extinction, which might be linked directly to humans. Long-line fishing has depleted their numbers. Fishermen throw bait in the ocean to lure fish, but they also lure albatrosses that get hooked and drown when they squat on the water to eat.
The birds also swallow marine debris; an estimated 4,500kg of plastic is unknowingly fed to albatross chicks each year by their parents, the USGS said. This might not kill the chicks quickly, but it restricts food intake, leading to dehydration. Also, the birds are threatened by invasive species, such as rats and wild cats, that prey on eggs, chicks and nesting adults.
Albatrosses aren't the world's largest birds, or the oldest — parrots in captivity have lived to 80, Peterjohn said. But they are stunning, easily the largest sea bird, with wingspans as wide as 2.4 metres – "like a seagull on steroids," Peterjohn said – dwarfing the average grey gulls that roam beaches stealing french fries.
But they are the oldest-known birds in the wild. Wisdom edged out the second-oldest-known albatross to give birth, a 61-year-old named Grandma, of the Northern Royal species, Peterjohn said. But Grandma hasn't been seen at her nesting ground at Taiaroa Head, New Zealand, in three years and is presumed dead.
Albatrosses mate for life, suggesting that Wisdom probably had to find a new, younger mate maybe twice down the line. They work at a relationship: "They dance together," said Chandler Robbins, a retired senior scientist at USGS. The birds face each other – eye to eye, beak to beak – and do a two-step, up and down, stretching their wings and craning their necks.
Robbins is part of the twist in Wisdom's story that makes it even more remarkable. He was in his 40s when he clasped that first aluminium band around Wisdom's ankle in 1956. Still working at age 81, he returned to the atoll in 2001 and, amid the thousands of albatrosses that nest there, picked up a bird with a tag that traced all the way back to one with a signature he recognised: his own. That's when scientists got excited and gave Wisdom her name, estimating her age at 49. But she could be several years older.
The tangled record-keeping that frustrates scientists has kept Robbins going at age 94. "I'm trying to straighten out the record," he said. "It takes a lot."