WASHINGTON (AP) -- 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.

They found on the two pristine South Pacific islands huge numbers of Moas, flightless birds that ranged up to 440 pounds. The animals had never seen people and, thus, had no sense of how dangerous humans could be. They were easy prey to the snares and clubs of hungry hunters.

A new study suggests the result was a quick extinction for all 11 species of the Moa, along with the disappearance of many other New Zealand plants and animals.

In a study appearing Friday in Science, two New Zealand researchers suggest that humans may have killed off all of the Moa, perhaps in only about 60 years.

"There has been a debate as to whether humans can exterminate anything by hunting," said Richard N. Holdaway of Palaecol Research in Christchurch, New Zealand. "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 damage took only decades.

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 geologic 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. He said the Moa could have disappeared in just 60 years.

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 co-factors, 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, hundreds of animals and plants were gone forever, said Holdaway. Error: Unable to read footer file.