Woodpeckers and Relatives: Piciformes

Woodpeckers and their relatives make up the order Piciformes, which includes six families of birds that nest in cavities (hollow areas within a rock or tree): jacamars (Galbulidae); puffbirds (Bucconidae); barbets (Capitonidae); honeyguides (Indicatoridae); woodpeckers, wrynecks, and piculets, (Picidae); and toucans (Ramphastidae).

Although the six families look very different, most piciform birds share a common adaptation that helps them live in trees. This special feature is zygodactylous (zye-guh-DACK-tuhl-us; "yoke-toed" or "X-shaped") feet, which have two toes in front and two toes behind. With this arrangement, the birds can easily grab onto bark while hopping along branches and running up and down tree trunks. Along with this special feature, woodpeckers and their relatives also have similar jaw muscles and tongues, and do not have down feathers (except the jacamars). The tongue is capable of sticking out of its bill up to 4 inches (10 centimeters) in the green woodpecker, allowing it to take insects from deep cracks and crevices.

Piciforms are small- to medium-sized birds. They also share similar skeletal features, especially with the bones of the vertebrae (spinal column), sternum (breastbone), and ribs. Many members have heavy, sturdy bills, but the general size and shape of the bills varies widely. Jacamars have longish pointed bills; puffbirds have large, broad, often hooked bills; barbets have largish, generally heavy, sometimes notched bills; woodpeckers have strong, tapering, often chisel-tipped bills; honeyguides have relatively short bills that can be either stubby or pointed; and toucans have huge, colorful bills. The colorful plumage (feathers) found on most of the birds is very different among all of the piciform birds. However, they almost always contain combinations of black and white with accents of red and yellow.

Males and females usually look alike, but with some small differences in the color of nape (back part of neck) patches and the presence or absence of feathers around the bill, or what is called their "moustaches." One exception is Neotropical barbets, which show a great difference between males and females with regard to plumage color and pattern. Woodpeckers (one of three groups in the family Picidae) are unique within the family, order, and, in fact, among all birds in that they have strong, extra-stiff tail feathers that are used to brace themselves against tree trunks while climbing vertically or hammering with their beaks. Barbets also use their tail as a brace, but only while digging nest cavities. Woodpeckers and relatives are 3 to 22 inches (8 to 56 grams) long and weigh between 0.3 and 20 ounces (8 and 569 grams).