© Gregg Thompson
  • Male.
  • Female (left with male to right). Note: brown head and barred back.

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Williamson's Sapsucker

Sphyrapicus thyroideus
Most birds in this group are adapted for climbing and perching in trees and range widely in size. The feet of most species have two toes pointing forward and two pointing back, a special adaptation for trunk-climbing known as a zygodactyl arrangement. The order includes families as diverse as the puffbirds and the toucans, but only the woodpecker family is found in Washington:
Woodpeckers have many adaptations that allow them to perch upright against tree trunks and feed on insects under the bark or within the wood of the tree itself. Further specialization has produced many aberrant forms with different behavior and feeding habits. Most use their strong claws and stiff tail feathers to brace themselves against tree trunks as they climb. The specially adapted skulls of woodpeckers allow them to pound hard on tree trunks to excavate nesting and roosting cavities, to find food, and to communicate and attract mates. A special arrangement of bones and elastic tissues allows woodpeckers to extend their long tongues and extract insect prey from the holes they chisel with their strong, sharp beaks. The principal food of most woodpeckers is insects, especially the larvae of wood-boring beetles. A few woodpeckers feed on ants, nuts, or flying insects. Many also take a small amount of fruit. Most woodpeckers have rounded wings and an undulating flight pattern. The plumage of most is some combination of black and white, though brown is not uncommon. Many, especially males, have small patches of red or yellow on their heads. Although they may appear to damage trees, woodpeckers are generally good for tree health because they feed so heavily on wood-boring beetles. Most woodpecker species are monogamous, and many form long-term pair bonds. The nests are usually lined with nothing but the woodchips created by excavating the nest cavity, which is excavated by both members of the pair. Both sexes incubate the eggs, with males generally taking the night shift. Both sexes also feed and tend the young.
Uncommon summer resident east.
  • Species of Concern

General Description

The largest of Washington's sapsuckers, Williamson's Sapsuckers are striking birds. Males and females look very different from each other, and until 1873 they were mistakenly believed to be of different species. The upperparts of males are solid black. They have a large white rump patch and a large, showy white patch on each wing. Males have yellow bellies, bright red throats and black breasts. Their heads bear a white moustache line and white eye-line. The backs and wings of females are finely barred with light and dark brown. Like males, females have yellow bellies, black breast-bands, and white rumps, but their wings have no white wing-patches. Females' heads are brown, without conspicuous stripes. Juvenile plumage is mostly barred and mottled brown, without conspicuous markings.


Williamson's Sapsuckers breed in dry, open, conifer forests in mountainous regions, especially along rivers and in areas with western larch. They appear to be most successful in conifer forests with many different species of trees. During their migration they use a wide variety of habitats, and in winter they often use broadleaved forests, especially along rivers and streams.


Sapsuckers get their name from their foraging strategy of drilling holes in tree trunks, and then coming back to those holes later to feed on the running sap and the insects attracted to that sap. Unlike most woodpeckers, they forage in healthy trees and can actually kill a tree if they drill too many sap-holes around its trunk, although this is quite uncommon. Williamson's Sapsuckers also chip bark from trees to get to insects boring beneath. Their flight is deeply undulating. Although they are typically described as quiet and inconspicuous, they make loud, cat-like mewing calls, which may reveal their presence. They frequently sunbathe, facing away from the sun with their wings extended, tails spread, crown feathers raised, and heads held back.


Williamson's Sapsuckers are omnivores and feed on sap, insects, and fruits. During the nesting season they eat mostly ants, and they feed ants to their young.


Williamson's Sapsuckers form monogamous pairs, a bird often pairing with its mate from a previous year. They typically nest in larch or aspens with dead heartwood but a solid outer layer. The male excavates a new nest cavity every year. The nest is lined with woodchips from the excavation but no other lining. Both sexes typically incubate the 4 to 6 eggs for 12 to 14 days, and both brood the young for the first week after they hatch. Both feed the young, which leave the nest after 31 to 32 days and may disperse soon after they leave. Williamson's Sapsucker pairs usually raise a single brood each year.

Migration Status

In areas where sap freezes, Williamson's Sapsuckers are complete migrants, traveling in flocks to the American Southwest and Mexico for the winter. Females tend to migrate farther south than males.

Conservation Status

Williamson's Sapsuckers are considered a keystone species, because many other species use the sap wells they drill. Forest management tends to limit the availability of nest sites, as these birds prefer trees with soft, decayed centers for nesting, trees that are often removed from managed forests. Audubon~Washington lists them as a species-at-risk. The Breeding Bird Survey reports strong declines in the Pacific Northwest in recent years, but its data are difficult to interpret because few survey routes go through the breeding range of the Williamson's Sapsucker. Formerly they were encountered only very infrequently in Washington, but a more thorough understanding of their breeding requirements has made them easier to find.

When and Where to Find in Washington

From April through September, Williamson's Sapsuckers are uncommon breeders east of the Cascade crest. They are to be found most commonly in the Okanogan and Methow Valleys at elevations of 3,000 feet and above, especially in larch forests. Stampede Pass and Colockum Pass (Kittitas County) are other good locations. They are fairly common in the Okanogan Highlands and the eastern side of the Blue Mountains.

Abundance Code DefinitionsAbundance

C=Common; F=Fairly Common; U=Uncommon; R=Rare; I=Irregular
Pacific Northwest Coast
Puget Trough
North Cascades
West Cascades
Okanogan RUUUUU
Canadian Rockies RRRR
Blue Mountains RFFFFFFU
Columbia Plateau

Washington Range Map

North American Range Map

North America map legend

Federal Endangered Species ListAudubon/American Bird Conservancy Watch ListState Endangered Species ListAudubon Washington Vulnerable Birds List
Early Warning

View full list of Washington State's Species of Special Concern