WOODPECKERS BIOLOGY

Rex E. Marsh Fig.1. Red-headed woodpecker, Melanerpes erythrocephalus (left); downy woodpecker, Picoides pubescens (right).

Specialist in Vertebrate Ecology (retired) Department of Wildlife, Fisheries, and Conservation Biology University of California Davis, California 95616

Fig. 1. Red-headed woodpecker, Melanerpes erythrocephalus (left); downy woodpecker, Picoides pubescens (right).

ADDITIONAL INFORMATION

Woodpeckers

Identification

Woodpeckers belong to the order Piciformes and the family Picidae, which also includes flickers and sapsuckers. Twenty-one species inhabit the United States. Woodpeckers have short legs with two sharp-clawed, backward-pointed toes and stiff tail feathers, which serve as a supportive prop. These physical traits enable them to cling easily to the trunks and branches of trees, wood siding, or utility poles while pecking. They have stout, sharply pointed beaks for pecking into wood and a specially developed long tongue that can be extended a considerable distance. The tongue is used to dislodge larvae or ants from their burrows in wood or bark.

Woodpeckers are 7 to 15 inches (18 to 38 cm) in length, and usually have brightly contrasting coloration. Most males have some red on the head, and many species have black and white marks. Identification of species by their markings is quite easy. In most species, flight is usually undulating, with wings folded against the body after each burst of flaps.

Range

Woodpeckers are found throughout the United States. The three most widely distributed species are the hairy woodpecker (Picoides villosus), the downy woodpecker (P. pubescens, Fig. 1), and the yellow-bellied sapsucker (Sphyrapicus varius). Different species are responsible for damage in different regions.

Habitat

Because they are dependent on trees for shelter and food, woodpeckers are found mostly in or on the edge of wooded areas. They nest in cavities chiseled into tree trunks, branches, or structures, or use natural or preexisting cavities. Many species nest in human-made structures, and have thus extended their habitat to include wooden fence posts, utility poles, and buildings. Because of this, woodpeckers may be found in localities where trees are scarce in the immediate vicinity.

Food Habits

Most woodpeckers feed on tree-living or wood-boring insects; however, some feed on a variety of other insects. Some flickers obtain the majority of their food by feeding on insects from the ground, especially ants. Others feed primarily on vegetable matter, such as native berries, fruit, nuts, and certain seeds. In some areas, the diet includes cultivated fruit and nuts. The sapsuckers, as the name suggests, feed extensively on tree sap as well as insects.

General Biology, Reproduction, and Behavior

Woodpeckers are an interesting and familiar group of birds. Their ability to peck into trees in search of food or excavate nest cavities is well known. They prefer snags or partially dead trees for nesting sites, and readily peck holes in trees and wood structures in search of insects beneath the surface. One common misconception is that they peck holes in buildings only in search of insects. While they do obtain insects by this means, many species will drill holes in sound dry wood of buildings, utility poles, and fence posts where few or no insects exist. The acorn woodpecker (Melanerpes formicivorus) drills holes in wood simply to store acorns. When sapsuckers drill their numerous rows of 1/4-inch (0.6-cm) holes in healthy trees they are primarily after sap and the insects entrapped by the sap.

Woodpeckers have characteristic calls, but they also use a rhythmic pecking sequence to make their presence known. Referred to as “drumming,” it establishes their territories and apparently attracts or signals mates. Drumming is generally done on resonant dead tree trunks or limbs; however, buildings and utility poles may also be used.

Woodpeckers breed in the spring, commonly laying in the range of 3 to 5 or 4 to 6 eggs. The incubation period is generally short, lasting from 11 to 14 days. It may be longer for larger species. Most species are born naked; some are born downy. All are tended by both parents. Having 2 broods per year is fairly common and some species may have 3 broods. Apparently, both sexes sleep in cavities throughout the year.

Some species, such as the northern flicker (Colaptes auratus) and the redheaded woodpecker (Melanerpes erythrocephalus, Fig. 1), are migratory, but most live year-round in the same area. Most species live in small social groups; a few, such as the Lewis’ woodpecker (Melanerpes lewis), may, in certain seasons, occasionally be seen in flocks of several hundred.

Editors

Scott E. Hygnstrom; Robert M. Timm; Gary E. Larson

Prevention and Control of Wildlife Damage Logo 1994

PREVENTION AND CONTROL OF WILDLIFE DAMAGE — 1994

Cooperative Extension Division Institute of Agriculture and Natural Resources University of Nebraska -Lincoln

United States Department of Agriculture Animal and Plant Health Inspection Service Animal Damage Control

Great Plains Agricultural Council Wildlife Committee

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