Woodpeckers on the wing, such as the pileated, red-headed and northern flicker, reveal patches on the wings, tail or rump that can help you identify them. Males often show more red on the head than females, but for some species, like the red-headed woodpecker, it is impossible to distinguish between the sexes. Their specialized zygodactyl feet, with two toes pointing forward and two back, help them get a firm grip on vertical surfaces. They use stiff tail feathers to brace themselves as they scoot up and down trees. When woodpeckers drum, they're doing more than just making noise.
Woodpeckers can hear when an insect is hiding beneath bark or in a hollow part of the tree.
Then they use their heavy, chisel-shaped bill to peck beneath the tree bark, but it takes more than a sharp bill to do the job. Powerful neck muscles drive the blows, and their thick but spongy skull is designed to spread and absorb the shock of repeated pounding and to protect the brain. Woodpeckers have long tongues supported by bones that wrap over the top of the skull and attach in their nostrils. The bristle tip at the end of their tongue helps them fish out insects hiding in the deep cracks of trees. Trees and forests stay healthier because of woodpeckers' eating habits.