Texas Tech Curator Discovers Secret of Flight for World’s Largest Bird

Study shows largest bird ever glided through skies; takeoffs difficult.

At the size of a Cessna 152 light aircraft, the world’s largest bird couldn’t take off entirely by flapping its wings. It just wasn’t strong enough.

But when it came to flying, Argentavis maginicens glided lazily on updrafts and thermals as it searched for prey and soared over the Andes Mountains just as modern condors would do 6 million years later, said Sankar Chatterjee, Horn professor of museum sciences and curator of paleontology at the Museum of Texas Tech University. Once airborne, the bird could take 200-mile trips across the sky with ease.

Chatterjee published his findings in the journal Proceedings of the National Academy of Sciences. He and other researchers used software originally written for helicopters to analyze the aerodynamics of the largest bird known to have taken flight.

Like today's condors, Argentavis was a lazy glider that relied either on updrafts in the rocky Andes or thermals on the grassy pampas to provide lift, Chatterjee said.

"Think about a super-sized bald eagle with a 21-foot wingspan," Chatterjee said. "It would darken the sky. It’s almost like a tale from the ‘Arabian Nights.’ It was a very aggressive bird that flew over the pampas of Argentina to sweep down from the sky and seize large prey with a formidable beak."

Chatterjee said he and other scientists estimated the flight parameters of fossilized Argentavis bones and put that data into two computer algorithms commonly used in flight simulation. Based on the power that would have been available from its pectoral muscles, the authors concluded that Argentavis would have been incapable of flight powered entirely by wing flapping, but could soar efficiently.

"The hardest part would be taking off from the ground," he said. "It needs so much force for a 140-pound giant bird to fly, and that that would be a limiting factor. But we came up with two possibilities. Perhaps it jumped off an Andean cliff, then glided lazily about the sky.

But then there’s a problem when it tried to take off on the plains. Well, like a hang glider pilot, it could run down a slope and take off. Once it found a thermal, it would circle and climb vertically within the rising column of air."
Chatterjee grabbed headlines in January after releasing an article on Microraptor Gui – a 125-million-year-old feathered dinosaur from China with two sets of wings that it used to fly like a biplane.
"The Aerodynamics of Argentavis, the World’s Largest Flying Bird From the Miocene of Argentina," was authored by Sankar Chatterjee, R. Jack Templin and Kenneth E. Campbell Jr. For a copy of this or for a picture of the bird, please contact John Davis at (806) 742-2136 or e-mail john.w.davis@ttu.edu.

CONTACT: Sankar Chatterjee, Department of Geosciences, Museum of Texas Tech University, 806-742-1986, sankar.chatterjee@ttu.edu.