Woodpeckers are found worldwide in areas with trees and a temperate climate. They range in size from 3.5 inches to 2 feet. The largest North America species is the pileated woodpecker, which is 16.5 inches long with a wingspan of 29 inches. Most species have a dominant plumage pattern of black or brown and white, with additional splashes of red or yellow. Woodpeckers are scansorial, much like the ancient bird Archaeopteryx. To facilitate tree climbing, they have sharply curved claws and strong zygodactyl feet. Most birds have four toes, with one toe (hallux) directed backward and the others forward (anisodactyl foot). This type of foot is ideal for perching, but in woodpeckers the fourth toe is directed backward along with the hallux to produce a foot with two toes forward and two toes rearward, more suited to tree climbing and clinging. A few woodpecker species have lost one of the rear toes and are referred to as three-toed woodpeckers. Rectrices act as props for the woodpecker when climbing, resulting in a hitching motion as the bird moves. These stiff tail feathers are critical for climbing activities, and during molting, the center two feathers are preserved until the rest of the tail feathers are replaced, whereas in other birds the center feathers are the first to be lost. Stout, chisel-like bills are used to peel bark and excavate wood in search of insects or larvae to eat. Bills are also employed to carve out roosting and nesting cavities in trees and for drumming. Both the skull and bill are designed to absorb the shock of repeated pounding on wood. The sturdy feet and claws together with the rectrices form a triangular brace for the hard pounding by the bill. Woodpecker tongues are very long and wrap around the skull to anchor at the base of the bill. Extension of the tongue to retrieve food is accomplished by a complex system featuring long hyoid (tongue-base) bones. Some woodpecker tongues have barbs to help extract insects and larvae from chiseled holes, while sapsucker tongues are shorter, with fine, hairlike processes to aid in capturing sap and associated insects. Nostrils of woodpeckers are protected from the “sawdust” that excavating bills create by bristles or by being reduced to narrow slits. Wings are tapered, with a low aspect ratio (ratio of length to width). This wing configuration is designed for rapid takeoff and swift evasive flight maneuvers to capture prey, such as flying insects, or to escape predators. The eyes are positioned on the side of the head, giving the bird a wide field of vision to help spot predators. This ocular arrangement produces a predominantly monocular vision in which the environment is seen by only one eye. Binocular vision, providing depth perception important for flying and landing, is present in a relatively narrow field of vision straight ahead.
Thanks for description - Animal life club