>....that gave the beginnings of flight?
>
>January 16, 2003
>Scientist Offers New Hints to the Evolution of Flight
>By JAMES GORMAN
>
>The behavior of chukhar partridge chicks, which can run straight up the side
>of a hay bale or a tree while flapping their wings, may offer a new window
>on the origin of flight in birds.
>
>Feathered dinosaurs may have done something similar, Dr. Kenneth P. Dial of
>the University of Montana suggests in today's issue of Science. He suggests
>that they too flapped their wings to help them climb, which brought them off
>the ground and closer to discovering the aerial possibilities of their
>wings. Even incompletely feathered proto-wings, Dr. Dial says, would have
>been useful in running up steep inclines.
>
>One of Dr. Dial's findings, which has surprised other scientists who study
>the evolution of flight, is that the chicks he studied did not use their
>wings to raise them up, off the ground. The wing beats served the same
>purpose as spoilers on race cars. The force generated by flapping pressed
>the chicks into the surface on which they were running for better traction.
>As Dr. Dial said of his finding, "It's not intuitive."
>
>He came upon the behavior by accident. His teenage son, Terry, was helping
>him study the development of flight in chukhar chicks. While Dr. Dial was
>away on a trip, his son was keeping track of the young birds as their
>feathers grew and they gradually launched themselves on longer flights, both
>horizontally and vertically.
>
>The vertical flights used hay bales as an obstacle. When Dr. Dial returned
>from a trip, he said, his son told him the chicks were not staying with the
>program. "They're cheating," Dr. Dial recalled his son telling him, "They're
>not flying anymore. They're running up."
>
>Dr. Dial had to see for himself, then he had to videotape the behavior, and
>then he had to do a series of experiments varying the incline and the
>surface the birds were running up, and clipping the feathers at different
>lengths.
>
>He found that the chicks were using a flight stroke, but changing the angle
>to press their feet against the running surface. More feathers meant more
>effective use of the wings, but partly feathered wings provided a
>significant benefit.
>
>Dr. Dial concluded that proto-birds with somewhat similar wings may have
>done the same thing, and that the climbing ability they gained would have
>given them an evolutionary edge, even if the wings were not yet useful for
>full flight.
>
>Once the proto-birds were up a bush, or wall or tree, they would be in a
>position to discover what wings could do in the air. This evolutionary path
>to flight, he says, is different than previous models in which proto-birds
>first launched either from the trees or the ground, called the arboreal and
>cursorial models. "It's both and neither," Dr. Dial said.
>
>The findings have intrigued other scientists. "First and foremost," said Dr.
>Kevin Padian of the University of California at Berkeley, "It's telling us
>something we never knew." Dr. Padian, who studies the evolution of flight,
>said: "Nobody knew that they ran up trees like this. Nobody knew that wings
>could generate this kind of force. It's a terrific study for those reasons
>alone."
>
>Dr. Padian said that Dr. Dial's demonstration of this new use of wings adds
>to earlier research that had determined that the dinosaur ancestors of birds
>had both feathers and the right limb structure to make a flight stroke. He
>said that even without flying ability, wings and feathers offered
>evolutionary benefit, in terms of isolation and catching prey. Those
>dinosaurs, he said, could have used a forward predatory grab very similar to
>a flight stroke. The new use of wings he said, offers an additional survival
>benefit for a proto-wing.
>
>Dr. Alan Gishlick, a paleontologist who also studies the evolution of
>flight, said, the research "for the first time gives us a modern analog for
>terrestrial origin of flight."
>
>Dr. Gishlick, who is at the National Center for Science Education in
>Oakland, Calif., a non-profit group that defends the teaching of evolution
>in public schools, said that the fossils of dinosaurs he has studied showed
>they had the bone and muscle structure for this use of wings. "Dinosaurs
>like velociraptor could have done this," Dr. Gishlick said.
>
>He was not suggesting that velociraptor flew, since it seems to have been a
>highly successful predator on the ground. A more likely candidate to want to
>escape gravity, said Dr. Gishlick, was microraptor, a tiny, feathered
>dinosaur the size of a pigeon that was certainly chased enough to make it
>want to run up into the sky.
>
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>
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