As a wide as a small plane: fossil bird with 6.4 metre wingspan unearthed

Fossilised bones uncovered in the US state of South Carolina belonged to the largest flying bird in history, with a wingspan of 6.4 metres, equal to that of a very small plane, a new study says.

The wingspan of Pelagornis sandersi was twice as wide as that of biggest modern-day flying bird, the royal albatross, said the research published in the Proceedings of the National Academy of Sciences on Monday.

Coupled with its long beak and sharp bony teeth, the enormous wings probably helped the bird hunt food as it glided over water about 28 million years ago.

However, it might have needed some help getting airborne, given its wings were too long to flap easily from the ground.

Scientists believe it may have made a running start downhill, or used air gusts - much like a hang glider - to make its way aloft.

Once in the air, study author Dan Ksepka, of the National Evolutionary Synthesis Centre in Durham, North Carolina, said the bird could probably soar for several kilometres without ever flapping its wings. "That's important in the ocean, where food is patchy," Ksepka said.