Wednesday, September 16, 2009

A Man-eating Bird?

Haast's Eagle attacking New Zealand moas / Artwork: John Megahan

A recent examination of fossils from the extinct Haast's Eagle (Harpagornis moorei) found that this massive raptor could hunt large animals rather than just scavenging.
It was at first thought to be a scavenger because its bill was similar to a vulture's with hoods over its nostrils to stop flesh blocking its air passages as it rooted around inside carcasses.

But a re-examination of skeletons using modern technology, including CAT scans, by researchers at Canterbury Museum in Christchurch and the University of New South Wales in Australia showed it had a strong enough pelvis to support a killing blow as it dived at speeds of up to 80kph.

With a wingspan of up to three metres and weighing 18kg, the female was twice as big as the largest living eagle, the Steller's sea eagle.

And the bird's talons were as big as a tiger's claws.
That sounds scary. But did it actually eat humans? The answer is maybe. Haast's Eagle most likely evolved to prey on moas, as depicted in the artist's conception above. Large flightless moas inhabited New Zealand prior to the arrival of humans and became extinct soon afterward. If a Haast's Eagle could kill a moa, most likely it had the ability to kill humans as well. That would seem to confirm an ancient Maori legend about a large raptor that could eat humans. However, I find it doubtful that Haast's Eagles ate humans very frequently as it failed to outlast its main source of prey. Even if the eagles killed some humans, they did not kill enough to maintain the species.

As an aside, the image at the top of the article comes from an article in PLoS Biology (summary) several years ago that explored the genetic relationships among the Haast's Eagle and other raptors. This giant raptor is most closely related to Australia's Little Eagle (Aquila morphnoides), a species slightly smaller than a Red-tailed Hawk (Buteo jamaicensis). (Take a look at this image comparing the feet of a Haast's Eagle and a Little Eagle.) The Haast's Eagle is more distantly related to other members of the Aquila genus, including North America's Golden Eagle (Aquila chrysaetos). This puts Haast's Eagle among the true eagles rather than the fish eagles.

Thanks to Chris Clarke for the links.