BERLIN, Oct. 1 (UPI) — A giant bird living in a Berlin zoo may have settled a scientific debate over the existence of a huge, dark species of sea eagle, researchers say.
For more than 100 years scientists argued over whether there were two species of Steller’s sea eagle, one with distinctive white feathers and one dark variety, or if the dark eagles were just a rare color variation, the BBC reported.
But a dark, captive Steller’s sea eagle born to white-feathered parents, and the only living bird of its kind, may have put the debate to rest.
The Steller’s eagle is the heaviest of all eagles, and it usually has brown and white plumage, sporting white feathers along the wings, legs and tail.
A different, dark form of the bird was first described as a separate species in 1887, with brown feathers all over except for a white tail.
But there have been few authenticated sightings, the last in 1968, leading many to presume if there were a darker species it was extinct.
But a young eagle at the Tierpark Zoo in Berlin, when it molted into its adult plumage, proved to be a rare dark specimen.
“It’s really a surprise if you suddenly have a bird which was considered extinct and not observed for about half a century, neither in the wild nor in captivity,” Tierpark’s Curator of Birds Martin Kaiser said.
The eagle molted into its adult plumage this year with only a white tail, making it the only known living bird of its kind.
However, Kaiser said, the fact that both its parents are the white-feathered variety means the dark eagle is a color variation, not a separate species.
“This is the evidence that it is a color phase only. … [For the female to] be a subspecies the parents must be also dark colored,” he said.
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