MARCH 24, 02:47 EST
Study: Birds Hunted to Extinction
By PAUL RECER
AP Science Writer
WASHINGTON (AP) — A huge, flightless bird called the Moa was extinct within
just a few decades after humans first arrived at the animals' New Zealand
homeland, suggesting that whole species can be wiped out more quickly than
once believed.
That's the conclusion of a new study appearing today in the journal Science.
Researchers said that the first humans arrived in New Zealand about the year
1250, bringing with them sharp stone points, wood and bone clubs, controlled
fire and a natural hunger for meat.
The Moas, some of which grew to 440 pounds, had no sense of how dangerous
humans could be and quickly fell prey to the snares and clubs of hungry
hunters, said Richard N. Holdaway of Palaecol Research in Christchurch, New
Zealand.
``There has been a debate as to whether humans can exterminate anything by
hunting,'' said Holdaway. ``Our study shows that not only can people hunt
things to extinction, but they can do it very quickly.''
Moa previously had been thought to have disappeared over about 1,000 years,
but the study by Holdaway and Christopher Jacomb of Canterbury Museum in
Christchurch indicates that the extinction occurred in 60 to 160 years.
Holdaway said the Moa were primed for extinction. The 11 species ranged from
birds that stood 6 1/2 feet tall and weighed hundreds of pounds to
turkey-sized fowl. They were the only known feathered birds without wings.
Their fatal characteristic may have been a lack of fear of humans.
``They would have been very easy to kill,'' said Holdaway. One expert
suggests obtaining a Moa for dinner would have been ``like plucking fruit''
for the stone-age hunters.
A study of the bones and other debris scattered about ancient human camp
sites in New Zealand shows that Moa was ``a major source of food for these
people, providing 30 to 40 percent of their caloric intake,'' said Holdaway.
But that only lasted for a few decades, he said. Eventually, Moa bones became
rarer and then disappeared altogether from the archeological record. Holdaway
believes New Zealand settlers hunted them to death.
``In effect, there was the removal of a complete ecosystem within 160 years
or less,'' said Holdaway.
The conclusion by Holdaway and Jacomb is considered controversial among
experts because of its speed and because some doubt that hunting alone is
ever sufficient to wipe out whole species.
``There are extinctions that have followed hard on the heels of human
arrivals, but as to it being caused by hunting alone, that doesn't seem
plausible,'' said Ross D.E. MacPhee, a zoologist at the American Museum of
Natural History. ``There must have been cofactors, such as disease.''
MacPhee said that vast numbers of extinctions occurred after humans arrived
in the Americas. Animals such as the mammoth, the camel, the horse and the
sabertooth tiger all disappeared after humans arrived about 11,000 years ago.
But he said the extinctions took about 400 years, not the short period that
Holdaway is proposing for the Moa in New Zealand.
Holdaway said that one reason for the rapid loss of the Moa was that the bird
lived for a long period of time and reproduced infrequently. When humans
started killing the adults and eating the Moa eggs, he said, the population
crashed quickly.
``We think this shows that when you push things too hard, you get to a point
where it suddenly falls down,'' he said. ``You may not even notice what is
happening until it is too late.''
Holdaway said the first New Zealand settlers, Polynesians who are the
ancestors of the present-day Maori, arrived about 1250. They brought with
them not only weapons, but also egg-eating rats that contributed to the
widespread New Zealand extinctions.
Within only a few decades, the Moa were gone, along with many ground birds,
frogs and snakes. History's largest eagle, a 35-pound bird called Haast's
eagle, was gone.
The settlers used fire as a weapon and tool, burning into extinction an
entire forest that was then replaced by grassland. An estimated 40 percent of
the woody plants became extinct, said Holdaway, and this destroyed habitats.
By the time Europeans arrived in New Zealand, in the 18th century, said
Holdaway, hundreds of animals and plants were gone forever.
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