Scientists believe modern birds are descended from dinosaurs, and examples of feathered dinos have been found dated to 120 million years ago.
In an effort to determine the flight abilities of the animals, researchers built models of these early birds and launched them into the air.
The result: They glide nicely.
The ancient bird, Microcaptor gui, had feathers on both its arms and legs. Fossils were found in China and a joint team from the University of Kansas and Northeastern University in China has been studying it in hopes of learning how bird flight began.
Since modern birds don't have flight feathers on their legs the researchers weren't sure how to position Microraptor's legs.
They report in Tuesday's edition of Proceedings of the National Academy of Science that they constructed a model of the animal with its hind legs in three different potential positions.
"The controversy was that these animals couldn't spread their hind-wings to glide," said David Burnham of the University of Kansas. "But we've been able to articulate the bones in their hip socket to show that they could fly."
Successful flight tests were conducted at KU.