Ancient DNA Helps Solve The Legend Of Giant Eagles

McMaster University anthropologist Michael Bunce has shed new light on the evolution of the extinct Haast’s eagle, the giant bird that once ruled the skies over New Zealand.

Weighing between 20 and 30 pounds, the enormous Haast's Eagle dominated its environment. It was 30 to 40 per cent heavier than the largest living bird of prey around today, the Harpy Eagle of Central and South America.

Working in New Zealand, Bunce extracted DNA from fossil eagle bones dating back about 2000 years.

He says, "When we began the project it was to prove the relationship of the extinct Haast's Eagle with the large Australian Wedge-tailed Eagle. But the DNA results were so radical that, at first, we questioned their authenticity."

The results showed that the New Zealand giant was in fact related to one of the world's smallest eagles – the Little Eagle from Australia and New Guinea, which typically weighs under two pounds.

"Even more striking was how closely related genetically the two species were. We estimate that their common ancestor lived less than a million years ago. It means that an eagle arrived in New Zealand and increased in weight by 10 to15 times over this period, which is very fast in evolutionary terms. Such rapid size change is unprecedented in birds and animals," adds Bunce.

Before human settlement 700 years ago, New Zealand had virtually no terrestrial mammals. Apart from bats, the only inhabitants were approximately 250 species of birds. At the top of the food chain was the Haast's Eagle, the only eagle known to have been the top predator in a major terrestrial ecosystem. The eagles hunted moa, the herbivorous, flightless birds of New Zealand, which can weigh more than 400 pounds. Scientists believe the eagle died out within two centuries of human settlement of New Zealand.

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