The other day I received an email from a person who swears he saw three giant eagles as big as men on a roadway a few years ago. He went on to describe them – yellow eyes, yellow legs, rusty-rainbow colors on the shoulder, large beak like a big toucan- a good description of Great Blue Herons. That’s what I told him but he insists that these were new species of giant eagles unknown to science (because he couldn’t find them in any books). He says they have been found all over the U.S. but are rare and only seen during migration. I said it is very unlikely- nay, impossible- that giant eagles exist without birders knowing about them. Then he sends me an article from some supernatural-oriented magazine which reports a sighting of a giant eagle which flew off with a 50-pound deer in its talons. The article describes the bird and again it fits that of a Great Blue Heron plus some very exaggerated details.
Great Blue Herons are certainly unusual looking, often described as prehistoric in appearance. Once I was called by a TV station to look at the video they shot of a bird as big as a small plane that was reported to be hunting children – a Great Blue Heron.
This gentleman kept emailing me, convinced that giant eagles exist because “I know what I saw,” as if that was evidence. (I received the same comment from a person who said he saw an Ivory-billed Woodpecker in Oregon.) The giant eagle proponent told me of other sightings and that I should “ask around” of birdwatchers and other ornithologists if they have seen these birds. I kept trying to make the point that it’s evidence, not anecdotes, that is needed to prove the existence of these creatures – photos, bones, feathers, DNA, not stories. If 100 people swore to me that they have seen giant eagles, it would be meaningless. One hundred anecdotes do not make one piece of evidence. And of course, all the stories are from people who know little about birds.
Occam’s Razor, basic logic, says that that the simplest of competing ideas should always be preferred to the more complex, and that the answer should be one that has the fewest assumptions. The simplest explanation here is that the observer saw a large existing known species of bird but no unknown giant eagles.
Fifteen new species of birds have been discovered in the 2020’s so far, but many been in difficult to access areas such as the high Andes and tropical forests in the islands of Indonesia. Others just came about as a reevaluation of museum specimens – in other words, we knew about the birds, but a reanalysis of their DNA revealed they were previously undiscovered species. If you look at the whole list of new bird species discovered since 1900, you’ll find that they typically were small birds in isolated habitats.
There did exist a large eagle, Haast’s Eagle, in New Zealand, at one time, but it was hunted to extinction in the 1400’s by the Maori’s. But to call it a giant at 33 lbs is a bit of an exaggeration. And then there’s the myth of the Thunderbird, another giant bird unknown to science.
A new species of giant eagle in the U.S. would certainly be a spectacular find, but I’m not holding my breath.