Biggest Flying Seabird Had 21-Foot Wingspan, Scientists Say

Gliding like a massive albatross, the 25-million-year-old bird may have soared just above the ocean waves for long distances.

The largest seabird ever found (skeletal reconstruction, top) dwarfs a California condor (left) and royal albatross (right).

Soaring above the world's oceans some 25 million years ago, the largest seabird ever to fly boasted a 21-foot (6.4-meter) wingspan, paleontologists reported Monday.

The ancient bird, dubbed Pelagornis sandersi, belonged to a family of now-extinct "toothed" birds.

The discovery also shows that, for some ancient flying birds, bigger may have been better. (Related: "Largest Flying Bird Could Barely Get Off Ground, Fossils Show.")

Described for the first time in the Proceedings of the National Academy of Sciences, the fossil bones of the big bird were uncovered just outside an airport in Charleston, South Carolina, in 1983.

"A giant bird lands at an airport 25 million years too soon—it's kind of amusing," says study author Daniel Ksepka of North Carolina State University in Raleigh. "Maybe he should have just waited and landed on the new runway."

Birds of a Feather

The wingspan of Pelagornis sandersi dwarfs that of today's biggest flier, the royal albatross, whose span measures a "mere" 11.5 feet (3.5 meters). And it rivals that of the largest flying bird on record: Argentavis magnificensa South American condor with a 23-foot (7-meter) wingspan that glided among the mountaintops of the Andes six million years ago.

"Pelagornis was certainly much lighter and a better 'flier'" than the vanished giant condor, says paleontologist Antoine Louchart of France's Institute of Functional Genomics in Lyon, who was not involved with the study.

The most interesting finding in the new study, says Louchart, is that the ancient seabird may have soared just above the ocean waves for long distances, rather than ascending air currents to maintain high altitudes, as some large birds do today.

A model of Pelagornis sandersi's flight suggests that larger wings actually meant less drag from wingtip turbulence once the flier was aloft. The challenge for this seabird would have come during takeoff.

At 48 pounds (21.8 kilograms), Pelagornis sandersi was not as heavy as a flightless ostrich—which can weigh 320 pounds (145 kilograms)—but it was still likely too heavy (and had feet too tiny) to run on the water and take off like a goose or other waterfowl. (Related: "Giant Prehistoric Bird Crushed Seeds, Not Little Horses.")

"I think they just waited on the beach for a strong wind to carry them aloft," Ksepka says.

Ancient Oceans

More than 33 feet (10 meters) of ocean water covered the part of coastal South Carolina where the Pelagornis sandersi bones came to rest 25 million years ago. The bird's name honors Charleston Museum curator Albert Sanders, who uncovered the skull, wing, and leg bones of the ancient seabird ahead of runway construction three decades ago.

Ksepka says Sanders, an expert on ancient whales, "showed the bones to me in a drawer," where they awaited analysis for decades.

The so-called teeth of the bird were actually bony projections from its beak—good for spearing prey, which may have included other birds or other birds' prey.

Such "toothed" birds thrived from 55 million to 3 million years ago, before becoming extinct for reasons unknown.

"I would have loved to see one of them flying today," Ksepka says.

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