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| Wild Turkey Flight |
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Wild turkeys do have the ability to achieve flight from a standing start, unlike many other large birds
that must run a short distance. Most ground-dwelling game birds (wild turkeys, ruffed grouse, ring-necked
pheasants, bobwhile quail) do not have the capability of long, sustained flight. Instead they are designed to
accelerate quickly putting distance between the bird and a potential predator.
Unlike waterfowl, the breast muscle of these game birds is light in color and does not have an extensive
network of blood vessels that would be necessary for long duration flight. What these game birds do have in
common is a very high wing surface area per volume relationship. The square inches of wing surface in relation
to the volume of the body is very high. That is a design for fast acceleration. Indeed wild turkeys can
accelerate from 0 to 50 in just just seconds. Their top speed is between 50 and 60 miles per hour.
Sixty miles per hour translates to about 88 feet per second. The speed of sound is 1116 feet per second
at sea level at 59 degrees Fahrenheit (761.2 mph). So... the speed achievable by a wild turkey is a far
cry from Mach I and the ability to create a sonic boom. Aircraft have to exceed the speed of sound in order
to break the sound barrier and cause a sonic boom.
Now, the propulsion system of aircraft is vastly different from that of wild turkeys. Instead of the engine
producing thrust, the wild turkey's wings produce the
thrust necessary to accelerate. The primary and secondary wing feathers of wild turkeys are extremely stiff
(designed to bend very little and provide a great deal of "lift"). The wingbeats are very fast (a camera with
a shutter speed of 1/250th of a second barely stops the motion). The pressure created by those wingbeats causes
the feathers to flex producing noise. On the upswing of the wing, there may be some negative pressure created
and noise may be generated not only by the flexing of the heavy wing feathers but by air rushing in to fill the
void as the wings are pulled upward. The take off when a turkey is startled is pretty noisey, but it's definitely
not a sonic boom.
Bob Eriksen, CWB
NWTF Regional Biologist (PA,NJ,MD,DE)
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