Wing Angle May Be Key to Bird Flight Origins

Brian Handwerk
for National Geographic News
January 23, 2008

Young birds must master the right wing angles to become good fliers, according to new research that may shed light on the origins of flight itself.

Kenneth Dial of the University of Montana and colleagues have previously documented how birds can run up vertical trees, boulders, or cliffs by angling their wings to create wind force that holds them to the surface.

Even young birds use their small developing wings to perform these incredible feats. Babies master 60-degree slopes the day they hatch, and they tackle steeper challenges during the vulnerable period before they reach level flight.

"It has profound implications that an [undeveloped wing] has a function shortly after hatching for many birds," Dial explained.

Now his team has discovered that the secret of this behavior, and flight itself, begins with learning the optimal wing-to-ground angle needed to generate force.

It appears that both young and adult birds use the same angle for many types of locomotion leading up to level flight.

Tremendous Importance

The research, published in the current issue of the journal Nature, is an important addition to studies of living bird behavior, experts say.

"Birds use [undeveloped wings] to improve their locomotive performance and escape predators," Dial said. "Even if you take out the evolutionary implications, the ecological implications of that are enormous."

Kevin Padian, an expert on the origins of flight at the University of California, Berkeley, said the work is of tremendous importance for flight theory.

"This is really a good insight," said Padian, who was unaffiliated with the research.

"Essentially it says to me that [birds] are always going 'up and forward' in some sense, whether flying or running up trees, and so the angle of attack of the wings is sensibly the same, or nearly so."

Continued on Next Page >>




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