As an alternative, Ostrom suggested that perhaps wings first evolved as catching devices.(animatronic dinosaur) Today, small birds and bats use strokes of their wings to sweep prey into their mouth. Arcbaeopteryx wasn’t a strong flier—its major feathers weren’t fused to its arm and wrist the way they are in modern flying birds. So maybe Arcbaeopteryx had been a land-running predator that used its feathered, Deino-nycbus-type arms to coerce prey.
I accepted this hypothesis in an article about the renaissance of dinosaurs I published in Scientific American in 1975. (dinosaur equipment)But accumulating evidence has forced me back to the orthodox view of Arcbaeopteryx as a climbing and gliding flier. The aerodynamic shape of its flight feathers is the first consideration. Flying birds today have asymmetrical feathers—the leading edge is narrower and stronger than the trailing edge. This is a necessity for powered flight because air pressure is greater along each feather’s front edge. Recently, an ornothologist from North Carolina took the obvious step of carefully examining Arcbaeopteryx’s feathers—the first time anyone had done so since the initial discovery in 1861. There was no doubt, the wing’s main feathers were asymmetrical.
Therefore Arcbaeopteryx very probably did indulge in powered flight, even though it must have been a noisy, slow, and inelegant performer in the air. Furthermore, even though Arcbaeopteryx’s foot didn’t have as precise a grip as the most specialized modern perching birds do, it did have as much grasping power as many modern birds that climb adequately.(dinosaur factory) And Arcbaeopteryx wouldn’t have had to rely on its hind feet alone for effective climbing because its wings also had hooklike claws. Arcbaeopteryx certainly could have clambered through the ancient Bavarian vegetation as efficiently as any hoat zin chick. (dinosaur costume)Finally, if Archaeopteryx were a ground jogger, its hind claws would have been blunt like those of a modern ground bird. In fact, the Archaeopteryx’s feet ended in needle-sharp claws. And if it had run about on such pointed hind claws, it would have worn down their horny outer sheath. Yet the fossils display hardly any wear even on the delicate points of the claws.