Fossil of fearsome eagle from 25 million years ago found in stunning condition

In an "exquisite" discovery, scientists excavate a nearly complete skeleton of a mighty bird that used sneak tactics to ambush its prey.

Monisha Ravisetti Former Science Writer
Monisha Ravisetti was a science writer at CNET. She covered climate change, space rockets, mathematical puzzles, dinosaur bones, black holes, supernovas, and sometimes, the drama of philosophical thought experiments. Previously, she was a science reporter with a startup publication called The Academic Times, and before that, was an immunology researcher at Weill Cornell Medical Center in New York. She graduated from New York University in 2018 with a B.A. in philosophy, physics and chemistry. When she's not at her desk, she's trying (and failing) to raise her online chess rating. Her favorite movies are Dunkirk and Marcel the Shell with Shoes On.
Monisha Ravisetti
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Archaehierax sylvestris, ancient Australian eagle illustration

An illustration of Archaehierax sylvestris, an ancient eagle recently unearthed in Australia.

Jacob Blokland

Near a barren, dried-up lake in Southern Australia, scientists have uncovered the remains of an ancient eagle. The majestic bird is believed to have terrorized the turf 25 million years ago, when the land teemed with lush forests and, from the eagle's point of view, helpless prey. The discovery consists of a whopping 63 well-kept fossils comprising almost the entirety of the eagle's skeleton.

Flinders University paleontologist Trevor Worthy, co-author of a study on the find published Monday in the journal Historical Biology, calls the excavation "exquisite."

"It's rare to find even one bone from a fossil eagle," said Ellen Mather, first author on the study and doctoral candidate in paleontology at Australia's Flinders University. "To have most of the skeleton is pretty exciting," Mather said, "especially considering how old it is."

Eagles are at the apex of the food chain, with some preying on squirrels, prairie dogs and rabbits and using the sky as their safe haven. "They are always fewer in number -- and so are infrequently preserved as fossils," Worthy said.

Found near Australia's now-deserted Lake Pinpa, these plentiful fossils are not only a rare find, they also belong to one of the oldest, mightiest eaglelike raptors in the world. 

"This species was slightly smaller and leaner than the wedge-tailed eagle, but it's the largest eagle known from this time period in Australia," Mather said. The wedge-tail, or "wedgies" as they're known in Australia, are a broad-winged bird of prey of a similar size to America's bald eagle (The wedgie, though, would win in a fight).

Dubbed Archaehierax sylvestris, this prehistoric winged alpha of birds was unlike any eagle family we know of and had a relatively short wingspan. But it used that feature to its advantage.

Once upon a time, it expertly dodged trees and branches while stalking its victims, and it's thought to have attacked animals by ambush, armed with a colossal foot span of nearly six inches. High up in the trees, say the researchers, the feathered hunter attacked koalas, possums and other vulnerable animals.  

"The largest marsupial predators at the time were about the size of a small dog or large cat, so Archaehierax was certainly ruling the roost," Mather said. "It was one of the top terrestrial predators of the late Oligocene, swooping upon birds and mammals that lived at the time."

The discovery is another in a recent line of remarkable fossil finds. Others include the remains of a prehistoric flying reptile discovered during a police raid, and an ancient sea monster that resembles a massive "swimming head."