Extinct giant raptor once ruled New Zealand's skies

WELLINGTON (Reuters Life!) - Long before humans fully colonized New Zealand some 750 years ago, a giant, and now extinct, eagle ruled the skies, swooping down on its prey of flightless birds, according to a new study.

Scientists have known about the existence of Haast's eagle for over a century based on excavated bones, but the behavior of these giant birds was not entirely clear.

Because of their large size -- these eagles weighed up to 40 lbs (18 kg) -- some scientists believe they were scavengers rather than predators.

But the new study showed that not only was Haast's eagle a fearsome predator that probably swooped on its prey from a high mountain perch, it also it evolved over a relatively short period of time from a much smaller-bodied ancestor.

Researchers Paul Scofield of the Canterbury Museum in New Zealand and Ken Ashwell of the University of New South Wales used computerized CT and CAT scans to reconstruct the size of the brain, eyes, ears and spinal cord of this ancient eagle.

These data were compared to values from modern predatory and scavenging birds to determine the habits of the extinct eagle.

"This work is a great example of how rapidly evolving medical techniques and equipment can be used to solve ancient mysteries," said Ashwell, co-author of the study.

It is also an example of how the oral traditions of ancient peoples and scientific research can sometimes reach the same conclusion, added lead author Scofield.

"This science supports Maori [native New Zealander] mythology of the legendary pouakai or hokioi, a huge bird that could swoop down on people in the mountains and was capable of killing a small child," he said.

Haast's eagle became extinct a mere 500 years ago, probably due to habitat destruction and the extinction of its prey species by early Polynesian settlers.

The study was published in the Journal of Vertebrate Paleontology.

(Writing by Miral Fahmy; Editing by David Fox)