Woodpeckers

Woodpeckers have a number of adaptations that permit the vigorous hammering of wood without damaging the bird. Their skull is thick-walled and the brain is cushioned by absorbent tissue, which helps withstand the physical shocks of their head blows. The tongue of the woodpecker is long, barbed, and sticky to help extract insects from crevices, and the organ is supported by an extended hyoid bone and its muscles. The bill of woodpeckers is stout and pointed, and it grows continuously because of the wear to which it is subjected. As an adaptation for gripping vertical bark surfaces, woodpeckers have feet in which two toes point forward and two backward. The stiff, downward-propping tail feathers of woodpeckers also provide mechanical support while they are pecking.

Most woodpeckers live in forests, eating arthropods in or on trees, but a few species occur in more open habitats, where they often forage on the ground for arthropods. Some species are at least partly herbivorous, seasonally eating soft fruits and nuts. Many species of woodpeckers are migratory, while others are resident throughout the year in or near their territories. All of the true woodpeckers nest in cavities that they excavate in the soft, rotted interior of living or dead trees. However, some birds in the family use natural cavities or are secondary users of the abandoned excavations of other birds.