Why Yellow Birds Mysteriously Turn Red
No one could figure out why a North American woodpecker's feathers were changing color—until now.
For the yellow-shafted northern flicker, “you are what you eat” has proven freakishly true.
These eastern North American woodpeckers get their name from a thin vein of yellow that runs through the center of their dark feathers.
In the past few decades, ornithologists have noticed some the birds' yellow feathers have mysteriously turned red. (See National Geographic's backyard bird identifier.)
At first researchers thought the birds were somehow interbreeding with the red-shafted northern flicker, which is lives in the West. Yet some of the oddly red birds were thousands of miles away from their western cousins.
The answer, it turned out, had to do with their diets: The birds were eating red berries that turn their feathers crimson, according to new