Giant eagle filled the role of a predator on Kiwi island 750 years ago

In a new study, scientists have determined that the role of a predator, before humans colonized New Zealand about 750 years ago, was filled by a giant, extinct raptor known as Haast's eagle.

Although the bones of Haast's eagle have been known for well over a century, the behavior of these giants has been a point of debate.

Owing to their large size - these eagles weighed up to 40 lbs., larger than any modern eagle - some scientists believe they were scavengers rather than predators.

The new study, by Paul Scofield of the Canterbury Museum in New Zealand and Ken Ashwell of the University of New South Wales, used computed axial tomography (CAT/CT) 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.

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

"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.

"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," said Paul Scofield, lead author of the study.

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.