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Desert Diary
Biology/Half Wing


What good is half a wing? That's a question that has stymied scientists for years—how was the transition accomplished from the featherless forelimbs of bird ancestors to wings? Traits have to be continuously useful, since evolution can't anticipate future needs. Finding dinosaur fossils with feathers
not for flight, but presumably for display, solved one question. Two major attempts addressed the next step for flight: from the ground up, where it's envisioned that flapping the feathered forelimbs increased speed and probability of escape, and from the trees down, where any increase in surface area would allow gliding and decrease damage from a fall.

Now, a new finding throws light on the problem. Working with Chukars, a bird related to quail and introduced into our region, it's been found that even the underdeveloped wings of young birds allow efficient running up a steep slope. The wings are used to press the feet firmly to the surface, allowing birds to run up even a perpendicular surface. Finally we're able to see what good half a wing is.
pen and ink

Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.


Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.