This Turkey Tuesday is about primaries – the stiff, rigid feathers on the wing that allow flight. Like many birds, wild turkeys use their primary feathers to generate thrust when they need to fly, but there’s more to these showy, barred feathers than meets the eye. First, turkeys have 10 primaries on each wing, and the barring (black and white) is a way to age birds – juvenile birds (< 1 year old) will lack barring at the ends of the outermost feathers. Second, primaries are attached to the manus (the bird’s “hand”) and can be individually adjusted like fingers, offering the bird agility when in flight. Third, toms use their primaries to draw attention while they’re strutting, those feathers dragging the ground is a sound distinctive to their courtship displays. Lastly, the amount of barring (white versus black) differs across the subspecies. Easterns have slightly more black than white barring, whereas Osceolas have little white barring which results in their wings looking almost black – this is consistent with Gloger’s rule that postulates that animals in warm, humid regions with dense vegetation should be darker colored. On the other hand, as you head west you see turkeys with more white barring – Rio Grandes have barring that’s pretty equal between white and black, whereas Merriam’s and Gould’s have more white than black, causing their wings to appear brighter, with almost a pale shine to them. The take home is, even something as simple as a turkey’s wing feather speaks volumes about their age, behavior, adaptability, and geographic location.
Photo by Stephen Spurlock.