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Flap-Running Considered the Link Between Dinosaurs and Flight

on July 2, 2011

Why fly when you can flap-run up the evolutionary tree?

If you were a bird, wouldn’t you rather fly up a steep hill than run? Well, some birds don’t. A study published in the Journal of Experimental Biology reveals the advantage of Wing Assisted Incline Running (WAIR)1 and suggests this behavior explains how dinosaurs evolved the ability to fly.

In an effort to explain why pigeons habitually choose to flap-run uphill despite good flight capabilities, Dr. Brandon Jackson and colleagues implanted electrodes in the flight muscles of a group of pigeons. They measured muscle activity as the birds flew or flap-ran up various inclines.

Once the incline reached 65 degrees, the electrodes revealed that the energy expenditure for flap-running was only about ten percent of the energy required to ascend in flight. “The birds seemed to be using hardly any power to flap their wings as they ran up the slopes,” said Jackson.

WAIR is a crucial step in the flight training of baby birds. “Flap running . . . lets young birds that cannot yet fly - because of small muscles, small wings, weak feathers, etc - get off the ground and away from some predators,” Dr. Jackson said.

“And if baby birds can perform these behaviours, benefit from them, and transition gradually to flight in their life-time,” he added, “we think it's probable that dinosaurs with (similarly small wings) could have performed these behaviours, benefited from them, and transitioned towards flight over evolutionary time.”

“Very small wings powered by small muscles had aerodynamic function and survival benefits when they were flapped,” he concluded. “No more major steps were required after that, just gradual but beneficial steps. And we can actually observe [those steps] in developing birds today.”

Thus, because birds can conserve energy using WAIR and because baby birds train for flight this way, evolutionists believe WAIR to be “the extant biomechanical analogs for incremental adaptive stages in the evolutionary origin of flight.”2

An aerodynamic wing design, feathers, lightweight bones, and a respiratory system unique to the demands of bird flight are in no way acquired by running around and flapping.

The anatomical changes required for bird flight, however, go way beyond getting a good upper body work-out. An aerodynamic wing design, feathers, lightweight bones, and a respiratory system unique to the demands of bird flight are in no way acquired by running around and flapping. Furthermore, the author blithely refers to “very small wings” as if there were any evidence that dinosaurs had them. Without the wings, the show is over before it gets off the ground.

The study does a great job of revealing the design advantage of certain behaviors available to adult birds, fledglings, and even flightless birds. WAIR enables them to climb with less effort, exercise flight muscles before learning to fly, and negotiate obstacles. God created birds on the fifth day of creation week, and He designed them well. But these results do not show how flight evolved or how a reptilian creature could obtain the genetic information to become a bird.

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  1. Jackson, B. E., B. W. Tobalske, and K. P. Dial. “The Broad Range of Contractile Behaviour of the Avian Pectoralis: Functional and Evolutionary Implications,” Journal of Experimental Biology, April 5, 2011,
  2. Ibid.


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