PALEONEWS:Study Says Early Humans Caused a Quick Extinction of a Bird Species

[Betty Cunningham <bettyc@flyinggoat.com>]

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Study Says Early Humans Caused a Quick Extinction of a Bird Species

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. 

-- 
Flying Goat Graphics
http://www.flyinggoat.com
(Society of Vertebrate Paleontology member)
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