Pileated Woodpecker

A male Pileated Woodpecker

The population of this species has increased in recent decades, as former farmland has grown into mature forest habitat across much of the continent.

Adaptations for climbing and probing

A Pileated Woodpecker using its tongue to extract ants from a tree

In most situations, the woodpecker’s bill is an excavating tool. It is the tongue that functions as the means of procuring and manipulating food.

The long tongue has a barbed and sticky tip, and tiny muscles that allow the bird to bend the tip of the tongue in any direction, so it can follow twisting tunnels, trap prey against the walls, and pry insects and larvae out of their hiding places deep inside a tree.

A long and flexible neck allows the head and bill to swing in wide arcs and generate enough force for excavating holes in the wood, and also allows the head and bill to maneuver so that the tongue can probe crevices.

Sharp, curved claws and very strong legs and feet cling to bark.

The stiff tail is used as a prop, holding the body away from the trunk.

Two toes forward and two back form a wider grasp, gripping the bark from many different angles.

The extendable tongue of woodpeckers depends on some remarkable adaptations. The tongue is connected to the hyoid bones (shown in blue), which are flattened and flexible so they can curl around the skull, but they are still rigid enough to extend the tongue (imagine a plastic strap). These bones slide freely inside a sheath that wraps around the back and top of the skull all the way to the forehead. Two muscles (shown in red) work in concert to move the tongue in and out. Both muscles have one end attached to the skull near the back of the jaw, and the other end attached to the hyoid bones—one at the back end of the bones, the other in the middle. Other species with long tongues, such as hummingbirds (see this page) use a similar system.

With muscle A contracted and B relaxed, the tongue is pulled into the bill.

When muscle B contracts and A relaxes, the hyoid bones are pulled forward and the tongue extends out of the bill.