Kiwi DNA link spurs rethink of flightless birds

Before you go, we thought you'd like these...

Kiwi DNA link spurs rethink of flightless birds
A kiwi chick hatches at Auckland Zoo in Auckland, Wednesday, Sept. 12, 2012, during its spring breeding season. The chick, a flightless bird that will grow to about the size of a domestic fowl, is the fifth born this season and has been named Nick 1. (AP Photo/New Zealand Herald, Greg Bowker) AUSTRALIA OUT, NEW ZEALAND OUT
In this undated photo released by Canterbury Museum, a skeleton of adult brown kiwi, or Apteryx australis, is displayed next to an egg of a huge elephant bird, or Aepyornis maximus. A report published Friday in the journal Science indicates the kiwi’s closest relative is an enormous, long-extinct bird from Madagascar called the elephant bird. (AP Photo/Canterbury Museum, Kyle Davis and Paul Scofield) EDITORIAL USE ONLY
A keeper holds in his hands two Kiwi chicks at the zoo on June 19, 2012 in Berlin. Female chick Tea hatched three weeks ago, her still nameless brother is two weeks old. AFP PHOTO / JOHANNES EISELE (Photo credit should read JOHANNES EISELE/AFP/GettyImages)
NEW ZEALAND - CIRCA 2003: Little Spotted Kiwi or Little Gray Kiwi (Apteryx owenii), Apterygidae, Fiordland, South Island, New Zealand. (Photo by DeAgostini/Getty Images)
NEW ZEALAND - CIRCA 2003: Little Spotted Kiwi or Little Gray Kiwi (Apteryx owenii), Apterygidae, Fiordland, South Island, New Zealand. (Photo by DeAgostini/Getty Images)
NEW ZEALAND - CIRCA 2003: Southern Brown Kiwi, Tokoeka or Common Kiwi (Apteryx australis), Apterygidae, Canterbury Region, South island, New Zealand. (Photo by DeAgostini/Getty Images)
WELLINGTON, NEW ZEALAND - JULY 04: The Spotted Kiwi at the Karori Sanctuary, Wellington, Tuesday. Twenty of the spotted Kiwi, one of the rarest species of the bird were released into the sanctuary. (Photo by Robert Patterson/Getty Images)
WELLINGTON, NEW ZEALAND - JULY 04: Prime Minister Helen Clark with one of the Spotted Kiwi at the Karori Sanctuary, Wellington, Tuesday. Twenty spotted Kiwi, one of the rarest species of the bird were released into the sanctuary. (Photo by Robert Patterson/Getty Images)
ROTORUA, NEW ZEALAND: A highly endangered North Island Brown Kiwi chick 'Puta-nui,' Maori for 'born big' as he weighed 405 grams at birth, is weighed for the Department of Conservation's 'Operation Nest Egg' at Rainbow Springs in Rotorua 29 November 1999, which successfully breeds the flightless nocturnal birds in captivity. Kiwis (Apteryx australis), unique to New Zealand, are currently declining at an annual rate of six percent and may be extinct by 2020 without the captive breeding program. (ELECTRONIC IMAGE) AFP PHOTO/Torsten BLACKWOOD (Photo credit should read TORSTEN BLACKWOOD/AFP/Getty Images)
ROTORUA, NEW ZEALAND: Highly endangered North Island Brown Kiwi chicks 'Taz' (L) and 'Jake' (R) are checked by Department of Conservation biologist Diedre Vercoe for 'Operation Nest Egg' at Rainbow Springs in Rotorua 29 November 1999 which successfully breeds the flightless nocturnal birds in captivity. Kiwis (Apteryx australis), unique to New Zealand, are currently declining at an annual rate of six percent and may be extinct by 2020 without the captive breeding program. (ELECTRONIC IMAGE) AFP PHOTO/Torsten BLACKWOOD (Photo credit should read TORSTEN BLACKWOOD/AFP/Getty Images)
A Large Statue Of The Kiwi, New Zealands National Bird, Can Be Found In Queenstown. (Photo By: MyLoupe/UIG Via Getty Images)
Little Spotted Kiwi North Island New Zealand. (Photo By: MyLoupe/UIG Via Getty Images)
Kiwi bird at San Diego Zoo. (Photo by Loomis Dean//Time Life Pictures/Getty Images)
circa 1910: A close-up study of a young Kiwi bird. (Photo by Hulton Archive/Getty Images)
A man wearing glasses holding the Percy Kiwi Bird while its long beak is sucking up a live worm. (Photo by Fred Lyon//Time Life Pictures/Getty Images)
Kein Kiwi.
Milford Sound. Un Kea ci smonta la macchina
Kiwi bird at San Diego Zoo. (Photo by Loomis Dean//Time Life Pictures/Getty Images)
of
SEE ALL
BACK TO SLIDE
SHOW CAPTION +
HIDE CAPTION

By NICK PERRY
Associated Press

WELLINGTON, New Zealand (AP) -- Research linking New Zealand's diminutive kiwi with a giant extinct bird from Africa is prompting scientists to rethink how flightless birds evolved.

A report published Friday in the journal Science says DNA testing indicates the chicken-size kiwi's closest relative is the elephant bird from Madagascar, which grew up to 3 meters (10 feet) high and weighed up to 250 kilograms (550 pounds) before becoming extinct about 1,000 years ago.

The authors say the results contradict earlier theories that the kiwi and other flightless birds, including the ostrich and emu, evolved as the world's continents drifted apart about 130 million years ago.

Instead, they say, it's more likely their chicken-size, flight-capable ancestors enjoyed a window of evolutionary ascendancy about 60 million years ago, after dinosaurs died out and before mammals grew big.

Those birds, the authors say, likely flew between the continents, with some staying and becoming the large, flightless species we know today.

Alan Cooper, a professor at the University of Adelaide in Australia and a co-author of the paper, said the DNA results came as a huge surprise given the differences in size and location between the kiwi and elephant bird.

"This has been an evolutionary mystery for 150 years. Most things have been suggested but never this," he said. "The birds are about as different as you can get in terms of geography, morphology and ecology."

Cooper, a New Zealander by birth, is hoping the paper will also bring him a measure of redemption.

That's because two decades ago, Cooper and other scientists discovered genetic links between the kiwi and two Australian flightless birds, the cassowary and the emu. That led to New Zealanders believing their iconic bird might have come from Australia, a traditional rival.

"There was a huge outpouring of angst," Cooper said. "New Zealanders weren't too impressed."

The nation's identity is so entwined with the bird that New Zealanders call themselves kiwis and have also given the name to their currency and the kiwifruit.

But it turns out that if the emu was a cousin to the kiwi, the elephant bird was a sibling. Cooper said it has taken until now for DNA techniques to advance enough to get a usable result from the ancient bones of the Madagascan bird.

Cooper said the bird took its name from Arabic legends that suggested it was so fearsome it could grab an elephant with its talons.

There's little basis for the legend given the bird was a flightless herbivore. In fact, it was likely humans that hunted it into oblivion, Cooper said.

Trevor Worthy, a research fellow at Australia's Flinders University and a paper co-author, said it's likely the kiwi stayed small and took to eating insects at night because it didn't want to compete for habitat and food with another New Zealand flightless bird, the moa, which is also now extinct. He said it's strange the kiwi and elephant bird are such close relatives.

"One got big, one stayed little," he said.

Massey University professor David Penny, who wasn't involved in the research but who peer reviewed it for Science, said the results are very interesting and help complete the puzzle of flightless birds.

Read Full Story

People are Reading

The Latest from our Partners
1 - 3 of 15